Technical Field
[0001] The present invention relates to a multi-thread chain stitch sewing machine typically
represented by a horizontal tube type multi-thread chain stitch sewing machine, which
forms multi-thread chain stitch seams with a needle thread and a looper thread, and
is provided with a seam ravel preventing apparatus for preventing a ravel from occurring
in a certain portion at the end of sewing of multi-thread chain stitch seams.
Background Art
[0002] The horizontal tube type multi-thread chain stitch sewing machine includes one or
more needles moving up and down while holding a needle thread, and a looper which
moves forward and backward while holding a looper thread in a direction substantially
orthogonal to a vertical movement path of the needle. In this sewing machine, a needle
thread loop formed below a needle plate by the needle is caught by the forward movement
of the looper, and the needle thread is interloped by the looper thread held by the
looper, thereby forming the multi-thread chain stitch seams.
[0003] General multi-thread chain stitch seams formed by the multi-thread chain stitch sewing
machine have suffered from the following problem. That is, as shown in Fig. 20, when
an end portion of a looper thread 10 cut at the end of sewing is pulled in a direction
indicated by the arrow in Fig. 20, the looper thread 10 slips out of the last needle
thread loops 20a and 20b respectively formed by needle threads 20 and 20. The slipping-out
is likely to propagate toward a sewing start point, thus causing ravel throughout
the entirety of the seams.
[0004] This ravel occurs similarly in multi-thread chain stitch seams formed with a needle
thread or two or more needle threads and a looper thread.
[0005] For the purpose of preventing the ravel peculiar to the seams formed by the multi-thread
chain stitch sewing machine, the present applicant has already developed and filed
the patent application related to the following multi-thread chain stich sewing machine
with a ravel preventing apparatus (hereinafter referred to as the technique described
in an already-filed patent application of the present applicant).
[0006] The ravel preventing apparatus for the multi-thread chain stitch sewing machine of
the technique described in the already-filed patent application (A two-needle sewing
machine is described here.) is configured by including (i) needles 2 and 2 (refer
to Figs. 11 to 17) moving up and down while holding the needle threads 20 and 20,
with respect to needle drop positions A and A set with a distance laterally interposed
therebetween at a substantially middle portion of a needle plate P as shown in Figs.
21 to 23; (ii) a looper 1 (refer to Figs. 11 to 17) which can perform forward and
backward movements while holding a looper thread 10 in an arrangement direction of
the needle drop positions A and A, and catches needle thread loops 20a and 20b formed
below the needle plate P during the forward movement; (iii) a thread hanging hook
3 which can perform approach and departure movement with respect to the looper 1,
and swings around a vertically extending support shaft 30 between a standby position
away from the looper 1 as shown in Fig. 21, and a thread hooking position adjacent
to the looper 1 as shown in Fig. 23, in a plane substantially parallel to the needle
plate P, and a thread handling air cylinder (hereinafter including one called thread
handling cylinder) 32 as a hook actuator for drivingly swinging the thread hanging
hook 3 to the standby position and the thread hooking position; (iv) a swing lever
9 which is disposed at a position farther away from the needle plate P than the thread
hanging hook 3, and swings around a vertically extending support shaft 90 in the plane
substantially parallel to the needle plate P so that the needle thread loops 20a and
20b caught at the thread hooking position by the thread hanging hook 3 are held at
a hold position between the thread hooking position and the standby position, and
a stopper lever 4; (v) a stopper air cylinder (hereinafter including one referred
to as a stopper cylinder) 42 as a stopper actuator for drivingly swinging the stopper
lever 4 from an engaging position at which the stopper lever 4 engages with a part
of the swing lever 9, to a retracted position away from the engaging position; (vi)
a connecting rod 35 for interlockingly connecting the thread hanging hook 3 and the
swing lever 9; and (vii) a control section 8 (refer to Fig. 8) which performs selective
action control of the thread handling cylinder 32 and the stopper cylinder 42 after
terminating the normal sewing, and allows the needle thread loop 20b, one of those
caught at the thread hooking position by the thread hanging hook 3, to be held at
the hold position so that a sewing action for at least one stich is performed while
maintaining the hold state.
[0007] Structural members and structural portions in the ravel preventing apparatus of the
multi-thread chain stitch sewing machine of the technique described in the already-filed
patent application by the present applicant, which are identical to or corresponding
to a ravel preventing apparatus as an embodiment of the present invention described
later, are identified by the same reference numerals as in the embodiment of the present
invention, and their respective detailed descriptions are omitted here.
[0008] In the already-filed patent application by the present applicant, after terminating
the normal sewing, the foregoing sewing action for a stitch is performed by controlling
the actions of the thread hanging hook 3, the stopper lever 4, and the swing lever
9 via the control section. Thereby, as shown in Fig. 18, the looper thread 10 passes
through the final needle thread loop 20a on the right side (the left side in Fig.
18) that is formed finally in the multi-thread chain stitch seams M on a rear surface
of a fabric, and is turned back in front of the needle thread 20, which slips out
toward the rear surface of the fabric when sewing one stitch for preventing ravel,
and is then cut at a certain position after passing through the right final needle
thread loop 20a. On the other hand, the needle thread 20 on the left side (the right
side in Fig. 18), which slips out toward the rear surface of a fabric when sewing
the one stitch, passes through a final needle thread loop 20b finally formed at the
end of the normal sewing on the rear surface of the fabric, and allows the final needle
thread loop 20b to be selflooped, thereby forming chain stitch seams. Consequently,
the looper thread 10 enters into a state of being pressed between the left needle
thread 20 and the left final needle thread loop 20b, as shown in Fig. 18.
[0009] Although Fig. 18 shows a state in which the left final needle thread loop 20b and
the needle thread 20 are loose in order to clarify entanglement between the two, the
actual left final needle thread loop 20b is strongly tightened after the needle thread
20 passes therethrough, thereby entering into a state similar to that of the right
final needle thread loop 20a, as shown in Fig. 19. The looper thread 10 is strongly
pressed between the needle thread 20 and the left final needle thread loop 20b, and
is restricted in a state of being hung over the left final needle thread loop 20 and
the left needle thread loop 20c formed immediately before. This restriction is maintained
even when the looper thread 10 is subject to a force exerted from any direction, as
shown in Fig. 19, thereby surely preventing occurrence of ravel peculiar to the multi-thread
chain stitch seams M.
[0010] Thus, the multi-thread chain stitch sewing machine with the seam ravel preventing
apparatus according to the technique described in the already-filed patent application
by the present applicant is capable of effectively preventing the occurrence of ravel
peculiar to the multi-thread chain stitch seams. However, the following problem that
needs improvement remains unsolved in the multi-thread chain stitch sewing machine
with the seam ravel preventing apparatus.
[0011] That is, in the technique described in the already-filed patent application by the
present applicant, as shown in Figs. 21 to 23, the thread hanging hook 3, the stopper
lever 4, the swing lever 9, the thread handling cylinder 32, the stopper cylinder
42, which are the structural elements of the seam ravel preventing apparatus, are
supported to a laterally long and large needle plate base 11 which has the needle
plate P attached thereto, and is fastened to an upper surface of a sewing machine
bed. Specifically, the support shaft 30 for the swing of the thread hanging hook 3
is supported at a position in the vicinity of the rear side of the needle plate P
on the left side of the needle plate base 11. On the other hand, the stopper lever
4, the swing lever 9, the thread handling cylinder 32, and the stopper cylinder 42
are respectively supported at positions away from the needle plate P on the right
side of the needle plate base 11. Also, the connecting rod 35 is connected between
a front end portion of the swing lever 9 and a front end portion of an extended part
3c extended so as to be folded forward from the support shaft 30 for swinging the
thread hanging hook 3. Reference numeral 6 in Figs. 21 to 23 denotes a looper thread
holder fastened together with the thread hanging hook 3 via fixing screws 60 and 60.
[0012] Thus, in the multi-thread chain stitch sewing machine of the technique described
in the already-filed patent application by the present applicant, all the structural
elements of the seam ravel preventing apparatus are supported by the laterally long
and large needle plate base 11. Therefore, if after the needle plate base 11 with
the components of the ravel preventing apparatus installed and supported thereon is
attached to the upper surface of the sewing machine bed, it becomes necessary to adjust,
for example, stitch performation by correcting the positions and the loci of actions
of members performing sewing action which are stored below the needle plate base 11
and inside the sewing machine bed, such as the looper and the members for actuating
the looper, or it becomes necessary to perform maintenance, such as replacement of
various kinds of components incorporated into the sewing machine bed, an operating
space that is wide enough to perform the adjustment and the maintenance cannot be
ensured only by removing the needle plate P. Hence, to ensure the wide operating space,
it becomes necessary to perform an operation requiring labor in which predetermined
adjustment and maintenance are carried out after the entirety of the long large needle
plate base 11 is temporarily removed from the sewing machine bed, and thereafter the
entirety of the long and large needle plate base 11 is reattached to the sewing machine
bed.
[0013] Particularly, air tubes 33 and 43 for supplying operating air to the thread handling
cylinder 32 and the stopper cylinder 42 are respectively connected to these two cylinders.
Therefore, it becomes necessary to perform extremely bothersome and time-consuming
operation in which when removing and attaching the needle plate base 11, these two
air tubes 33 and 43 are pulled out from inside the sewing machine bed so that both
do not obstruct the removal and attachment operations, and after these operations,
both air tubes are pushingly returned to the inside of the sewing machine bed. However,
unless the bothersome and time-consuming adjustment and maintenance operations are
carried out, there is a probability that the stitch performation is deteriorated,
and a predetermined ravel preventing function cannot be reproduced. This necessitates
the extremely bothersome and time and labor consuming operations. This problem also
still remains unsolved.
Citation List
Patent Literatures
Summary of Invention
Technical Problem
[0015] The present invention has been made in view of the foregoing circumstances, and an
object thereof is to provide a multi-thread chain stitch sewing machine with a seam
ravel preventing apparatus, with which the occurrence of ravel peculiar to the multi-thread
chain stich seams can effectively be prevented, and the maintenance, such as the adjustment
of stitch performation by the position correction of the members for performing sewing
action, and the replacement of various kinds of components stored inside the sewing
machine bed can extremely easily and simply be carried out without having much trouble
and requiring labor and time, thereby allowing the stitch performation and predetermined
ravel preventing function to be constantly surely reproduced.
Solution to Problem
[0016] In order to achieve the above object, the multi-thread chain stitch sewing machine
with the seam ravel preventing apparatus according to the present invention includes
a needle moving up and down while holding a needle thread; a looper which is movable
forward and backward while holding a looper thread in a direction substantially orthogonal
to a vertical movement path of the needle, and catches a needle thread loop formed
below a needle plate by the needle during a forward movement; and a needle plate base
having the needle plate attached thereto and being attached to an upper surface of
a sewing machine bed. The multi-thread chain stitch sewing machine forms multi-thread
chain stitch seams on a fabric by allowing the looper to catch the needle thread loop
formed below the needle plate by the needle, and then by interlooping the needle thread
with the looper thread held by the looper. The multi-thread chain stitch sewing machine
with the seam ravel preventing apparatus includes (A) a needle thread holding mechanism
having (i) a thread hanging hook which is approachable and departable with respect
to the looper, and swings around a vertically extending support shaft in a plane substantially
parallel to the needle plate between a standby position away from the looper and a
thread hooking position close to the looper, and (ii) a hook actuator for drivingly
swinging the thread hanging hook to the standby position and the thread hooking position;
(B) a stopper mechanism having (iii) a stopper member which is disposed at a position
farther away from the needle plate than the thread hanging hook of the needle thread
holding mechanism, and permits temporary suspension and unsuspension of a swing of
the thread hanging hook from the hooking position to the standby position so that
the needle thread loop caught by the thread hanging hook at the thread hooking position
is held at a hold position between the thread hooking position and the standby position,
and (iv) a stopper actuator for performing the suspension and the unsuspension of
the stopper member; (C) a connecting member for interlockingly connecting the thread
hanging hook of the needle thread holding mechanism and the stopper member of the
stopper mechanism; and (D) a control section which controls the needle thread holding
mechanism and the stopper mechanism in association with a vertical movement of the
needle, forward and backward movements of the looper, and feed of the fabric, so that
the looper is moved forward after a normal sewing is terminated, the thread hanging
hook of the needle thread holding mechanism is brought near the looper, the needle
thread loop caught at the thread hooking position is moved to the hold position, a
resulting state is maintained until the needle descends through the needle thread
loop caught by the looper, and thereafter, a sewing action for at least one stitch
is performed.
[0017] The needle plate base is divided into two sections: a left needle plate base for
attaching a needle plate thereto and supporting a swinging support shaft of a thread
hanging hook; and a right needle plate base for fixedly supporting the stopper member
and the hook actuator and the stopper actuator. The right needle plate base is fastened
to the sewing machine bed. The left needle plate base is fastenably and unfastenably
fastened to an upper surface of the sewing machine bed via screw members.
Advantageous Effects of Invention
[0018] In the multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
having the foregoing characteristic features, after normal sewing is terminated, the
looper is moved forward, and the thread hanging hook of the needle thread holding
mechanism is brought near the looper, and the needle thread loop caught by the looper
is moved to the hold position and, in this state, the sewing action for at least one
stitch is performed. Accordingly, the preceding needle thread loop is self-looped
with the needle thread held by the descending needle, and the looper thread is held
down by the self-looped portion, thereby preventing slippage of the looper thread.
That is, a seam ravel can surely be prevented in its developmental stage.
[0019] Further in the present invention, the needle plate base attached to the sewing machine
bed is divided into the two sections: the right needle plate base for attaching the
needle plate thereto and swingably supporting the thread hanging hook of the needle
thread holding mechanism; and the right needle plate base for fixedly supporting the
stopper member of the stopper mechanism, the hook actuator, and the stopper actuator.
Hence, as compared with handling of the single long and large needle plate as in the
case of the technique described in the already-filed patent application by the present
applicant, the attachment (installation) of the entirety of the ravel preventing apparatus
with respect to the sewing machine bed can be easily carried out with less effort
because the left and right needle plate bases can be individually attached to the
sewing machine bed, and the ravel preventing apparatus can be incorporated into the
sewing machine bed.
[0020] Furthermore, if after the seam ravel preventing apparatus is incorporated into the
sewing machine bed, it becomes necessary to adjust stitch performation by correcting
the position and motion loci of components for carrying out the sewing action which
are stored below the needle plate base and inside the sewing machine bed, such as
the looper and the members for actuating the looper, or it becomes necessary to perform
maintenance, such as mending and replacement, on various types of components stored
below the needle plate base and inside the sewing machine bed, it is unnecessary to
remove the right needle plate base for fixedly supporting the hook actuator and the
stopper actuator to which an air tube or an electric power supply line is connected,
and a sufficiently wide operating space can be ensured by unfastening and removing
only the left needle plate base from the sewing machine bed.
[0021] Hence, the adjustment of sewing performation, and the maintenance such as the mending
and replacement on the various types of components stored inside the sewing machine
bed can be performed extremely easily, simply, and efficiently only by handling the
small and lightweight left needle plate base to which neither the air tube nor the
electric power supply line clings. This produces the effect that satisfactory sewing
performation and the predetermined ravel prevention function can constantly be exhibited
with superior reproducibility, thereby succeeding in solving the problem remained
unsolved in the already-filed patent application by the present applicant.
[0022] In the multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to the present invention, the stopper mechanism is preferably made up of
a stopper member which is directly connected to the hook actuator and moves linearly
reciprocally; a swing lever engageable with and disengageable from a part of the stopper
member; a spring for swingingly energizes the swing lever in a direction in which
the thread hanging hook is positioned at the standby position; and the stopper actuator
for disengaging the swing lever from the part of the stopper member against an energizing
force of the spring.
[0023] In this case, the action of the stopper member in a return direction (the action
in a direction in which the thread hanging hook is positioned at the standby position)
is performed by the energizing force of the spring. Therefore, the stopper actuator
for actuating the swing lever that engages with or disengages from the part of the
stopper member may be one capable of pushingly driving the stopper member. Hence,
the use of an air cylinder as the stopper actuator allows for employment of a single
acting type air cylinder, thereby achieving downsizing and cost reduction of the stopper
actuator.
[0024] In the multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to the present invention, the swing lever in the stopper mechanism is preferably
attached to a movable base attached laterally position-adjustably to the right needle
plate base.
[0025] In this case, by the lateral position adjustment of the movable base with respect
to the right needle plate base, the timing that the looper comes out of the needle
thread loop held by the thread hanging hook can easily and appropriately be adjusted
attached to ensure self-looping for seam ravel prevention.
[0026] In the multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to the present invention, the hook actuator of the needle thread holding
mechanism and the stopper actuator of the stopper mechanism are preferably fixedly
supported on a lower surface of the right needle plate base in a vertical two-stage
fashion.
[0027] In this case, the two actuators are fixedly supported on the right needle plate base
in the vertical two-stage fashion, and therefore the planar space occupied by these
two actuators can be reduced to permit compactness, thereby allowing them to be nicely
stored inside the sewing machine bed, compared with the case where the two actuators
are disposed at the positions separated from each other (side-by-side arrangement)
as in the case of the technique described in the already-filed patent application
by the present applicant.
[0028] In the multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to the present invention, the thread hanging hook of the needle thread holding
mechanism is preferably provided with a looper thread holder which holds the looper
thread extending from the looper to the fabric at a more forward position than the
drop position of the needle by swinging together with the thread hanging hook of the
needle thread holding mechanism around the support shaft in the plane substantially
parallel to the needle plate between the thread hooking position, the hold position,
and the standby position.
[0029] In this case, the looper thread is held at a position ahead of the drop position
of the needle by the looper thread holder that cooperates with the thread hanging
hook. This simple structure allows the looper thread to be surely positioned together
with the needle thread. Accordingly, the self-looping can be surely performed to more
surely prevent the seam ravel.
[0030] In the multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to the present invention, the looper thread holder is preferably attached
position adjustably to the thread hanging hook.
[0031] In this case, a relative position between the needle thread and the looper thread
can be appropriately set, and the self-looping can be performed more surely to further
enhance the seam ravel prevention effect.
[0032] In the multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to the present invention, the hook actuator of the needle thread holding
mechanism and the stopper actuator of the stopper mechanism are preferably both air
cylinders.
[0033] In this case, the thread hanging hook in the needle thread holding mechanism and
the swing lever in the stopper mechanism can be operated with superior response on
the basis of a control signal from the control section, thereby achieving the reliable
and efficient seam ravel prevention effect after the normal sewing.
[0034] As these actuators, electromagnetic solenoids or the like may be used.
[0035] In the multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to the present invention, a pin is preferably protruded upward from a connection
end portion of the connecting member, and a connection end portion of the thread hanging
hook is preferably provided with a connecting hole that is insertable into the pin
from above the pin, and is drawable in an upward direction.
[0036] In this case, when the left needle plate base is removed from the sewing machine
bed in an upward direction by unfastening it from the upper surface of the sewing
machine bed in order to perform the maintenance, such as mending and replacement,
on the various types of components stored inside the sewing machine bed, the connection
between the thread hanging hook and the connecting member can be released only by
raising the left needle plate base, without requiring any troublesome operation, such
as unfastening and removing a screw that connects the connecting member and the thread
hanging hook, or pulling-out of a connecting pin. Additionally, after the adjustment
and maintenance, the thread hanging hook and the connecting member can be returned
to the predetermined connected state only by fixedly fastening the left needle plate
base to the sewing machine bed from above. This further saves time and trouble during
the adjustment and maintenance.
[0037] In the multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to the present invention, the left needle plate base or the sewing machine
bed are preferably provided with protruding knock pins which are capable of positioning
the left needle plate base to the sewing machine bed at a plurality of positions away
from a plurality of fixedly connecting portions and connection release portions by
means of the screw members, and the sewing machine bed or the left needle plate base
is preferably provided with pin holes engageable with the knock pins.
[0038] In this case, when the left needle plate base is attached to and detached from the
sewing machine bed, the left needle plate base can be surely positioned at a predetermined
position in the sewing machine bed by the engagement between the plurality of knock
pins and pin holes. Therefore, even when the left needle plate base is repetitively
attached to and detached from the sewing machine bed every time the adjustment and
maintenance are carried out, the left needle plate base can be attached to the sewing
machine bed by constantly ensuring predetermined position and posture. Consequently,
besides the normal sewing, the seam ravel prevention function can also be constantly
performed appropriately surely.
[0039] The seam ravel preventing apparatus of the present invention is suitably applicable
to a horizontal tube type multi-thread chain stitch sewing machine.
Brief Description of Drawings
[0040]
Fig. 1 is a perspective view showing a general appearance of a horizontal tube type
multi-thread chain stitch sewing machine with a seam ravel preventing apparatus according
to an embodiment of the present invention;
Fig. 2 is a perspective view showing the structure of the main parts of the seam ravel
preventing apparatus in the horizontal tube type multi-thread chain stitch sewing
machine;
Fig. 3 is a perspective view showing a state in which a part of the structure of the
main parts of the seam ravel preventing apparatus is removed;
Fig. 4 is a plan view showing the structure of the main parts of the seam ravel preventing
apparatus;
Fig. 5 is a bottom plan view of the main parts for explaining the structure of a stopper
mechanism and a first action thereof in the seam ravel preventing apparatus;
Fig. 6 is a bottom plan view for explaining the structure of the stopper mechanism
and a second action thereof;
Fig. 7 is a bottom plan view for explaining the structure of the stopper mechanism
and a third action thereof;
Fig. 8 is a bottom plan view for explaining the structure of the stopper mechanism
and a fourth action thereof;
Fig. 9 is a block diagram showing the configuration of a control system of the horizontal
tube type multi-thread chain stitch sewing machine including the seam ravel preventing
apparatus;
Fig. 10 is a time chart for explaining operation contents of a control section in
the seam ravel preventing apparatus;
Fig. 11 is an explanatory drawing of a first ravel prevention action by the seam ravel
preventing apparatus;
Fig. 12 is an explanatory drawing of a second ravel prevention action by the seam
ravel preventing apparatus;
Fig. 13 is an explanatory drawing of a third ravel prevention action by the seam ravel
preventing apparatus;
Fig. 14 is an explanatory drawing of a fourth ravel prevention action by the seam
ravel preventing apparatus;
Fig. 15 is an explanatory drawing of a fifth ravel prevention action by the seam ravel
preventing apparatus;
Fig. 16 is an explanatory drawing of a sixth ravel prevention action by the seam ravel
preventing apparatus;
Fig. 17 is an explanatory drawing of a seventh ravel prevention action by the seam
ravel preventing apparatus;
Fig. 18 is a view of a seam structure of twin-needle multi-thread chain stitch obtained
by the present invention, viewed from the rear surface of a fabric;
Fig. 19 is an explanatory drawing of ravel prevention effect of the seam structure
shown in Fig. 18;
Fig. 20 is a view of a general seam structure in a portion at the end of sewing, viewed
from the rear surface of the fabric;
Fig. 21 is a plan view roughly showing the structure of the main parts of the seam
ravel preventing apparatus of the technique described in the already-filed patent
application by the present applicant;
Fig. 22 is a bottom plan view roughly showing the structure of the main parts of the
seam ravel preventing apparatus of the technique described in the already-filed patent
application by the present applicant; and
Fig. 23 is a plan view for explaining action states of the main parts of the seam
ravel preventing apparatus of the technique described in the already-filed patent
application by the present applicant.
Description of Embodiments
[0041] An embodiment of the present invention is described below with reference to the accompanying
drawings.
[0042] Fig. 1 is the perspective view showing the general appearance of the horizontal tube
type multi-thread chain stitch sewing machine according to the embodiment of the present
invention. Figs. 2 and 3 are the perspective views showing the structure of the main
parts of the seam ravel preventing apparatus included in the horizontal tube type
multi-thread chain stitch sewing machine according to the present invention. Fig.
4 is the plan view showing the structure of the main parts of the seam ravel preventing
apparatus. The following description is made using terms "left," "right," "forward,"
and "backward" indicated by arrows in Figs. 2 to 4. That is, the term "forward" denotes
the side near a sewing operator. The term "backward" denotes the side away from the
sewing operator. The terms "left" and "right" denote the left and right, viewed from
the front near the sewing operator.
[0043] In the present embodiment, structural members and structural portions, which are
identical to or corresponding to the technique of the already-filed patent application
by the present applicant described with reference to Figs. 21 to 23, are described
using the same reference numerals.
[0044] As shown in Fig. 1, in the horizontal tube type multi-thread chain stitch sewing
machine according to the present embodiment of the present invention, a sewing machine
arm C and a sewing machine bed B are extended substantially horizontally toward the
left from an upper position and a lower position of a body section D, respectively.
As shown in Fig. 4, the horizontal tube type multi-thread chain stitch sewing machine
includes a looper 1, two needles 2 and 2 (refer to Figs. 11 to 17), a needle plate
base 11 secured to an upper surface of the sewing machine bed B, a seam ravel preventing
apparatus H incorporated into the needle plate base 11, and a needle plate P secured
onto the needle plate base 11. The needles 2 and 2 move up and down via actions of
a needle bar driving mechanism. Alphabetic characters A and A in Figs. 2 and 4 denote
needle drop positions (descent positions) of the needles 2 and 2, respectively. The
needle drop positions A and A are set with a distance laterally interposed therebetween
at a substantially middle portion of the needle plate P.
[0045] The looper 1 moves forward and backward (left forward motion and right backward motion)
via the actions of the looper driving mechanism. A solid line in Fig. 4 indicates
a state in which the looper 1 has moved to a left forward position, and a broken line
in Fig. 4 indicates a state in which the looper 1 has moved to a right backward position.
As shown by the solid line in Fig. 4, a front end portion of the looper 1 at the left
forward position extends leftward across the needle drop positions A and A. As shown
by the broken line in Fig. 4, the front end portion of the looper 1 at the right backward
position is located rightward away from the needle drop positions A and A.
[0046] The horizontal multi-thread chain stitch sewing machine sews a fabric (not shown)
set on the needle plate P by the up and down movements of the needles 2 and 2, and
the left forward and right backward movements of the looper 1. The fabric is pressed
against the needle plate P by a presser foot (not shown), and is fed in a direction
of arrow Y in Fig. 4 by the action of a feed mechanism installed inside a sewing machine
bed B. The feed mechanism includes a feed dog that repeats the following movements
in which the feed dog moves in a backward direction while protruding from the needle
plate P, and moves in a forward direction while sinking under the needle plate P.
The fabric is intermittently fed in a direction of arrow Y by the feed dog.
[0047] The foregoing needle bar driving mechanism, looper driving mechanism, and feed mechanism
are well known mechanisms which operate mutually synchronously by power transmission
from a sewing machine spindle (not shown). The needles 2 and 2 respectively hold needle
threads 20 and 20 (refer to Figs. 11 to 17), and pass through the fabric and reach
below the needle plate P during discontinuation of the fabric feeding, and thereafter,
these needles move up and pass through the fabric in an upward direction. The looper
1 holds a looper thread 10 (refer to Figs. 11 to 17), and moves toward the left at
the same moment that the needles 2 and 2 start moving up, thereby catching loops 20a
and 20b of the needle threads 20 and 20 which are formed below the needle plate P.
The fabric is fed when the needles 2 and 2 move up. The needle 2 and 2 move down while
passing through the fed fabric, and catch the looper thread 10 held by the looper
1 retracted toward the right. The multi-thread chain stitch sewing machine forms multi-thread
chain stitch seams on the fabric by repeating the forgoing actions.
[0048] The seam ravel preventing apparatus H included in the foregoing horizontal tube type
multi-thread chain stitch sewing machine includes a needle thread holding mechanism,
a stopper mechanism, a connecting rod 35 as a connecting member for interlockingly
connecting a thread hanging hook 3 (described later) of the needle thread holding
mechanism and a stopper member 4 (described later) of the stopper mechanism, and a
control section 8 (described later).
[0049] The needle thread holding mechanism includes the thread hanging hook 3, and a reciprocating
type thread handling cylinder 32 as a hook actuator for drivingly swinging the thread
hanging hook 3 around a vertical extending support shaft 30 between a standby position
away from the looper 1 and a thread hooking position adjacent to the looper 1. The
supporting shaft 30 as the swing center of the thread hanging hook 3 is disposed in
the vicinity of a right back side corner of the needle plate P, and is supported on
the needle plate base 11.
[0050] The thread hanging hook 3 has an arcuately curved shape, and is continuously formed
so as to be folded forward at a front end portion of a support arm 3e extending leftward
from the support shaft 30. A front end portion of the thread hanging hook 3 is faced
onto the needle drop positions A and A from the left back on a lower side of the needle
plate P. An outward protruding hook portion 3b is formed at the front end portion
of the thread hanging hook 3. The support arm 3e has an extended portion 3c extending
forward from the support shaft 30, and one end of the connecting rod 35 is connected
to a front end portion of the extended portion 3c.
[0051] As shown in Fig. 4, a looper thread holder 6 having an arcuately curved shape is
fastened together with a base part of the thread hanging hook 3 via two fixing screws
60 and 60. A front end portion of the looper thread holder 6 extends forward substantially
along the left side of the thread hanging hook 3, and is faced onto the needle drop
positions A and A at a front position of the front end portion of the thread hanging
hook 3. A looper thread receiving portion 6a branched into two is formed at the front
end portion of the looper thread holder 6. The looper thread holder 6 permits position
adjustment with respect to the thread hanging hook 3 by unfastening the fixing screws
60 and 60. The position adjustment ensures holding of the looper thread 10 by the
looper thread receiving portion 6a located at the front end.
[0052] As shown in Figs. 5 to 8, the stopper mechanism is comprised of a stopper member
4 which is fastened to a front end portion (left end portion) of an output rod 31
of the thread handling cylinder 32 via a fixing screw 36, and is linearly reciprocally
drivingly moved in a lateral direction due to expansion and contraction of the thread
handling cylinder 32 by operating air supplied via an air tube 33; a swing lever 9
engageable with and disengageable from a part of the stopper member 4; a spring 91
which allows the swing lever 9 to be engaged with the part of the stopper member 4,
and swingingly energizes in a direction in which the thread hanging hook 3 is located
at the standby position; and a stopper cylinder 42 of single acting type (drivingly
push-out type in the left direction) as a stopper actuator which forcibly disengages
the swing lever 9 from the part of the stopper member 4 against the swing energizing
force of the spring 91.
[0053] The output rod 41 of the stopper cylinder 42 is configured to swing the swing lever
9 counterclockwise against the swing energizing force of the spring 91 as the stopper
cylinder 42 is drivingly pushed out toward the left by the operating air supplied
via the air tube 43.
[0054] The swing lever 9 is supported on the upper surface of a swing lever mount (movable
mount) 92 so as to be swingable around the center of the vertically extending support
shaft 90. The swing lever 9 has at a front end portion thereof an engaging claw 9a
engageable with the part of the stopper member 4. As shown in Fig. 5, the swing lever
9 is contacted with a side part of the stopper member 4 by the energizing force of
the spring 91 during the time the stopper member 4 is drivingly moved toward the left
by the expansion stroke of the thread handling cylinder 32, that is, during the time
the thread hanging hook 3 is moved to the standby position. As shown in Fig. 6, the
swing lever 9 swings clockwise around the support shaft 90 by the energizing force
of the spring 91, and the engaging claw 9a at the front end thereof enters a state
of being engageable with the part of the stopper member 4 while the stopper member
4 is drivingly moved toward the right by the contraction stroke of the thread handling
cylinder 32.
[0055] As shown in Fig. 7, by allowing the contracted thread handling cylinder 32 to resume
somewhat the contraction stroke, the engaging claw 9a at the front end of the swing
lever 9 engages with the part of the stopper member 4, thereby temporarily suspending
the leftward driving movement of the stopper member 4. In the state in which the stopper
member 4 is thus temporarily suspended, the thread hanging hook 3 moves to the hold
position between the standby position and the thread hooking position, and remains
there via the connecting rod 35. At this time, the hook portion 3b at the front end
of the thread hanging hook 3 moves from the thread hooking position shown in Fig.
4 (between the right and left needle drop positions A and A) to left back of the left
needle drop position A, and hooks the left needle thread 20 and holds it at the hold
position. The looper thread holder 6 moves forward to the front of the looper 1, and
the looper thread receiving portion 6a at the front end thereof holds the looper thread
10 at a more forward position than the left needle drop position A.
[0056] Further, as shown in Fig. 8, the swing lever 9 is swung counterclockwise against
the swing energizing force of the spring 91 by allowing the output rod 41 to be drivingly
pushed out toward the left as the stopper cylinder 42 expands. This swing allows the
engaging claw 9a at the front end of the swing lever 9 to be disengaged from the part
of the stopper member 4, thereby releasing the temporary suspension of the stopper
member 4. Consequently, the thread handling cylinder 32 is subjected to a maximum
expansion stroke, and the thread hanging hook 3 and the looper thread holder 6 are
swingingly returned to the standby position via the connecting rod 35.
[0057] As described above, in the present embodiment, the thread hanging hook 3 and the
looper thread holder 6 of the needle thread holding mechanism swing into the standby
position, the thread hooking position, and the hold position by the expansion and
contraction strokes of the thread handling cylinder 32 and the stopper cylinder 42.
[0058] The horizontal tube type multi-thread chain stitch sewing machine in the present
embodiment further includes a thread cutting mechanism 5 for cutting the needle threads
20 and the looper thread 10 after a sewing action is terminated. As shown in Figs.
16 and 17, the thread cutting mechanism 5 includes a thread cutting hook 50, a thread
cutting knife 51, a leaf spring 59 for pressing the thread cutting hook 50 against
a sliding contact part between itself and the thread cutting knife 51, and a thread
cutting actuator 58 (refer to Fig. 9). The thread cutting hook 50 has at a front end
portion thereof a first hook part 51 and a second hook part 53 which are protruding
backward. The thread cutting mechanism 5 is well known, and therefore, description
and illustration of other detailed structures are omitted here.
[0059] Fig. 9 is the block diagram showing the configuration of the control system of the
horizontal tube type multi-thread chain stitch sewing machine including the seam ravel
preventing apparatus H as described above. A pedal depresson signal 21a and a pedal
back signal 21b generated by a pedal switch 21, a needle position signal 22 generated
when the needles 2 and 2 are in the vicinity of a top dead center, a thread cut signal
23, and a needle thread wipe signal 24 are respectively inputted to the control section
8 of the multi-thread chain stitch sewing machine.
[0060] On the other hand, the control section 8 outputs action control signals to the thread
handling cylinder 32, the stopper cylinder 42, and the thread cutting actuator 58,
respectively. The thread hanging hook 3 and the looper thread holder 6 act as previously
described according to the action control signals outputted from the control section
8 to the thread handling cylinder 32 and the stopper cylinder 42, and the thread cutting
actuator 58 of the thread cutting mechanism (not shown) expands and contracts according
to the thread cut signal 23 outputted from the control section 8.
[0061] The control section 8 also outputs action control signals respectively to a sewing
machine motor 80 as a driving source of the sewing machine spindle, a presser foot
cylinder 81 for moving up and down a presser foot for pressing the fabric, an air
wiper 82 for wiping up the needle threads 20 and 20 to be cut as described later,
a feed reducing mechanism 83 for adjusting a fabric feeding rate, and a looper thread
restraining mechanism 84 for restraining the feed of the looper thread 10 to the looper
1.
[0062] The feed reducing mechanism 83 reduces the fabric feed rate by changing a mode of
operation of the feed dog in the feed mechanism. For example, time period during which
the feed dog acts on the fabric on the needle plate P is reduced by inclining an action
passage of the feed dog with respect to the needle plate P so as to reduce time period
during which it protrudes upward from the needle plate P, or a unit feed pitch by
the feed dog is reduced by changing a length of a lever for cyclically operating the
feed dog. The feed reducing mechanism 83 of this type is well known, and therefore
detailed illustration and description thereof are omitted here.
[0063] The looper thread restraining mechanism 84 includes a thread tension disc for squeezing
a midportion of the looper thread 10 to be fed to the looper 1, and an actuator that
operates to increase or decrease strength to squeeze the looper thread by the thread
tension disc. The strength to squeeze the looper thread by the thread tension disc
is enhanced to increase resistance applied to the looper thread 10, thereby restraining
the feed of the looper thread 10. The looper thread restraining mechanism 84 of this
type is well known, and therefore detailed illustration and description thereof are
omitted here.
[0064] At the end of the sewing for forming the multi-thread chain stitch seams, the control
section 8 executes a seam ravel prevention operation in the multi-thread chain stitch
seams by allowing the thread hanging hook 3 and the looper thread holder 6 to act
in association with the sewing machine motor 80, the presser foot cylinder 81, the
air wiper 82, the feed reducing mechanism 83, and the looper thread restraining mechanism
84.
[0065] Fig. 10 is the time chart showing time series operation contents of the control section
8 for the purpose of ravel prevention. The control section 8 is a computer including
a CPU, a ROM, and a RAM. The ravel prevention operation according to the time chart
shown in Fig. 10 is executed by a series of operations of the CPU according to a control
program stored in the ROM.
[0066] Figs. 11 to 17 are the explanatory drawings of the ravel prevention operation by
the ravel preventing apparatus H in the horizontal tube type multi-thread chain stitch
sewing machine of the present invention, and show operation statuses of the thread
hanging hook 3 and the looper thread holder 6, and the thread cutting hook generated
by the operation of the control section 8 according to the time chart of Fig. 10.
[0067] When the sewing operator using the sewing machine terminates normal sewing, the operator
suspends a depressing operation of a pedal for driving the sewing machine, and then
performs the ravel prevention operation. In this case, the operator performs a pedal
back operation of the pedal. The pedal switch 21, attached to the pedal, outputs the
pedal depression signal 21a during the pedal depression operation, and outputs the
pedal back signal 21b in response to the pedal back operation.
[0068] When the normal sewing is terminated, and the pedal for driving the sewing machine
is returned from a depressed state to a neutral state at time S1 in Fig. 10, namely,
when neither the pedal depression signal 21a nor the pedal back signal 21b is outputted
from the pedal switch 21, the control section 8 outputs a suspension command to the
sewing machine motor 80 by referring to the needle position signal given to the input
side. Consequently, the sewing machine is temporarily suspended in a state in which
the needles 2 and 2 are positioned in the vicinity of the top dead points and the
looper 1 has moved toward the left.
[0069] Thereafter, the control section 8 stands by until the pedal is subjected to the pedal
back operation. When the pedal back operation is performed, and the pedal back signal
21b is inputted to the input side at time S2 in Fig. 10, the control section 8 starts
the ravel prevention operation as described below. When the pedal depression signal
21a is inputted again from the pedal switch 21, the control section 8 returns to the
normal sewing action. Therefore, the sewing operator can continue the normal sewing
by performing the pedal depressing operation again.
[0070] In Fig. 10, though the neutral state is maintained during a period of time between
S1 and S2, maintaining the neutral state is not necessarily required. The pedal operation
at the end of the normal sewing may be continuously shifted from the pedal depression
state to the pedal back state. In this case, when passing through the neutral position
in the shift progress, it enters a non-signal state in which neither the pedal depression
signal 21a nor the pedal back signal 21b is outputted. Using the non-signal state
as a trigger, the control section 8 starts the ravel prevention operation after achieving
the state in which the needles 2 and 2 are raised to near the top dead points and
the looper 1 is moved toward the left, as described above.
[0071] Also in the time chart of Fig. 10, though the pedal back operation at time S2 is
continued during execution of the ravel prevention operation described later, it is
unnecessary to continue the pedal back operation until the ravel prevention operation
is terminated, and the ravel prevention operation is continuously executed by the
operation of the control section 8 even after the input of the pedal back signal 21b
is suspended.
[0072] Fig. 11 shows the states of the needles 2 and 2 and the looper 1 at the start of
the ravel prevention operation. The needles 2 and 2 have passed through and are now
located above the fabric on which multi-thread chain stitch seams M are formed by
the two needle threads 20 and 20 and the looper thread 10. The looper 1 has moved
toward the left below the fabric, and is in a state of catching the needle thread
loops 20a and 20a respectively formed by the needles 2 and 2. When the needle threads
20 and 20 and the looper thread 10 are cut in this state, the portion at the end of
sewing as shown in Fig. 20 is formed.
[0073] After starting the ravel prevention operation, the control section 8 firstly provides
an operation command to the thread handling cylinder 32 on the output side. In response
to this command, the thread handling cylinder 32 moves from a state of expansion shown
in Fig. 5 to a state of contraction shown in Fig. 6, and the stopper member 4 is drivingly
moved toward the right. Accordingly, the thread hanging hook 3 and the looper thread
holder 6 move from the standby position to the thread hooking position by swinging
around the support shaft 30 via the stopper member 4 and the connecting rod 35. At
this time, the hook portion 3b at the front end of the thread hanging hook 3 hooks
the needle thread loop 20a on one side (left side), and the swing lever 9 in the stopper
mechanism swings clockwise around the support shaft 90 by the energizing force of
the spring 91, and the engaging claw 9a at the front end thereof enters the state
of being engageable with the part of the stopper member 4.
[0074] Immediately thereafter, the control section 8 provides an operation command to the
thread handling cylinder 32. Under the operation command, the thread handling cylinder
32 expands somewhat from the state shown in Fig. 6 to the state shown in Fig. 7, and
the stopper member 4 is linearly drivingly moved toward the left. During the slight
expansion of the thread handling cylinder 32, the engaging claw 9a at the front end
of the swing lever 9 engages with the part of the stopper member 4, thereby temporarily
suspending a leftward driving movement of the stopper member 4. In the state in which
the leftward driving movement of the stopper member 4 is temporarily suspended, as
shown in Fig. 12, the thread hanging hook 3 moves via the connecting rod 35 to the
hold position between the standby position and thread hooking position, and remains
there and holds the left needle thread loop 20a at the hold position. The looper thread
holder 6 moves toward the front of the looper 1, and the looper thread receiving part
6a at the front end thereof holds the looper thread 10 at a more forward position
than the left needle drop position A.
[0075] After the thread hanging hook 3 and the looper thread holder 6 are thus moved to
and remain at the hold position, the control section 8 provides operation commands
respectively to the sewing machine motor 80, the feed-reducing mechanism 83, and the
looper thread restraining mechanism 84 at time S3 in Fig. 10. These operation commands
are provided by referring to the needle position signal 22 in a period of time during
which the needles 2 and 2 move down and move up again to the positions near the top
dead points. Accordingly, the sewing action for one stich on the fabric is carried
out. The sewing for the one stitch is carried out at a lower feed rate than during
the normal sewing by the action of the feed-reducing mechanism 83. The sewing for
the one stitch is also carried out by the action of the looper thread restricting
mechanism 84 in a state in which the feed of the looper thread 10 to the looper 1
is restrained. This improves tightness of the looper thread 10 at the end of the sewing,
thereby enhancing the ravel prevention effect described later.
[0076] As shown in Fig. 12, the thread hanging hook 3 and the looper thread holder 6 continue
the holding of the needle thread 20 and the looper thread 10 until the fabric feed
is completed, and the needles 2 and 2 pass through the fabric and move down, and the
left needle 2 passes through the needle thread loop 20a held by the thread hanging
hook 3 and catches the needle thread loop 20a. At this time, the looper thread 10
held by the looper thread holder 6 is located across the front of the left needle
2, as shown in Fig. 12. Hence, the left needle 2 does not catch the looper thread
10, and the looper thread 10 is merely caught behind the looper 2 by the right needle
2.
[0077] At the time the left needle 2 catches the needle thread loop 20a, namely, at time
S4 in Fig. 10, the control section 8 allows the stopper cylinder 42 of the stopper
mechanism to expand by providing an operation command to the stopper cylinder 42.
Accordingly, the output rod 41 is drivingly pushed out toward the left. Consequently,
as shown in Fig. 8, the swing lever 9 is swung counterclockwise against the swing
energizing force of the spring 91, and the engaging claw 9a at the front end of the
swing lever 9 is disengaged from the part of the stopper member 4, thus allowing for
a release of the temporary suspension of the stopper member 4. Upon the release of
the temporary suspension of the stopper member 4, the thread handling cylinder 32
is expanded to its maximum at time S4. Consequently, as shown in Fig. 13, the thread
hanging hook 3 and the looper thread holder 6 performs a return movement from the
hold position to the standby position by swinging around the support shaft 30 via
the stopper member 4 and the connecting rod 35, and then releases the holding of the
needle thread loop 20a and the looper thread 10.
[0078] The looper 1 then performs a right retraction action as the needles 2 and 2 move
down, and slips out of the caught needle thread loop 20a. Upon the slipping-out of
the looper 1, as shown in Fig. 14, the right needle 2 enters a state of catching the
looper thread 10 similarly during the normal sewing, whereas the left needle 2 enters
a state of catching the left needle thread loop 20a.
[0079] In this state, the looper 1 converts to a left forward movement, and the needles
2 and 2 convert to an upward movement. As shown in Fig. 15, the looper 1 that performs
the left forward movement catches the left and right needle thread loops 20a and 20b,
and the needles 2 and 2 that move up pass through the fabric in the upward direction.
Accordingly, the needle thread 20 caught by the looper 1 interloops the looper thread
at the position of the right needle 2, whereas the needle thread 20 performs so-called
selflooping, that is, looping the previously formed needle thread loop 20a with the
needle thread 20 at the position of the left needle 2.
[0080] After the sewing action for the one stitch, it is finished in a state in which the
needles 2 and 2 move up to the vicinity of the top dead points, and the looper 1 reaches
the vicinity of the end of the leftward movement. Thereafter, the control section
8 stands by until a thread cut signal 23 is applied thereto. Upon receipt of the thread
cut signal 23 at time S5 in Fig. 10, the control section 8 allows the thread cutting
actuator 58 of the thread cutting mechanism to perform a predetermined operation by
providing an operation command to the thread cutting actuator 58. Accordingly, the
thread hanging hook 50 reaches a forward movement end along the upper part of the
looper 1, as shown in Fig. 16. At this time, the first hook part 52 at the front end
of the thread cutting hook 50 passes through the needle thread loops 20a and 20b held
by the looper 1 to the left side of the looper thread 10 extending from the front
end of the looper 1 to the fabric, and the second hook part 53 is opposed to the left
needle thread 20 from the left side thereof.
[0081] Subsequently, the thread cutting hook 50 located at the forward movement end performs
a right backward movement. At this time, the first hook part 52 catches the looper
thread 10, and the second hook part 53 successively catches the two needle threads
20 and 20. The looper thread 10 and the needle threads 20 and 20 caught in this manner
are then pulled to a retraction end of the thread cutting hook 50, and are cut by
being brought into sliding contact with an edge portion at the front end of the thread
cutting knife 51, as shown in Fig. 17. An end portion of the cut looper thread 10
is held in sandwich fashion between the thread cutting hook 50 and the leaf spring
59 at a position closer to the looper 1 than a cutting position.
[0082] The looper thread restraining mechanism 84 continues to operate and applies a predetermined
tensile force to the looper thread 10 extending from the front end of the looper 1
to the fabric, until the foregoing thread cutting operation is terminated. This ensures
that the first hook part 52 at the front end of the thread cutting hook 50 catches
and cuts the non-loose looper thread 10.
[0083] After the foregoing cutting operation, the control section 8 stands by until a needle
thread wipe signal 24 is inputted thereto. When the needle thread wipe signal 24 is
inputted thereto at time S6 in Fig. 10, the control section 8 allows the air wiper
82 to operate by outputting an operation command to the air wiper 82. The air wiper
82 blows out air and blows up cut end portions of the needle threads 20 and 20 that
are continuous with the needles 2 and 2. Thereafter, the control section 8 allows
the presser foot cylinder 81 to act to raise the presser foot for pressing the fabric
by outputting an operation command to the presser foot cylinder 81 at time S7 in Fig.
10, thereby terminating the sequence of the ravel prevention operation.
[0084] The foregoing sequence of the ravel prevention operation produces the multi-thread
chain stitch seams M by the horizontal tube type multi-thread chain stitch sewing
machine, as shown in Fig. 18. Referring to Fig. 18, the looper thread 10 is passed
through the inside of the right needle thread loop 20a (the left in Fig. 18 in which
the seams M are viewed from the rear surface of the fabric) which is finally formed
in the multi-thread chain stitch seams M on the rear surface of the fabric, and is
turned back in front of the right needle thread 20 that goes through the rear surface
of the fabric during the sewing action for one stitch for the purpose of the ravel
prevention, and is then cut at a certain position after being passed through again
the inside of the right final needle thread loop 20a.
[0085] On the other hand, the left (the right in Fig. 18) needle thread 20 that goes through
the rear surface of the fabric during the sewing action for the one stitch for the
ravel prevention passes through the left needle thread loop 20b finally formed on
the rear surface of the fabric during the normal sewing, and forms a chain stitch
seam by selflooping the left final needle thread loop 20b, as previously described.
Therefore, as shown in Fig. 18, the looper thread 10 enters a state of being pressed
between the left needle thread 20 and the left final needle thread loop 20b.
[0086] In Fig. 18, the left final needle thread loop 20b is illustrated in a loose state
in order to clarify entanglement with the needle thread 20. However, as shown in Fig.
19, the actual left final needle thread loop 20b is strongly tightened after the needle
thread 20 passes therethrough, and enters the same state as the right final needle
thread loop 20a. Then, when the cut end portion of the looper thread 10 is pulled
in the arrowed direction as shown in Fig. 19, the loop of the looper thread 10 passing
through in front of the right needle thread 20 is contracted and pulled into the right
final needle thread loop 20a. As a result, the needle thread 20 enters a state of
being held between the looper thread 10 and the right final needle thread loop 20a,
and the needle thread 20 and the looper thread 10 make a knot as shown in Fig. 19.
This knot also applies resistance to the looper thread 10, and performs the function
of preventing slipping-out of the looper thread 10. Accordingly, in the state as shown
in Fig. 19, the left selflooping portion and the right knot cooperate to surely prevent
the ravel of the multi-thread chain stitch seams M.
[0087] The characteristic features of the multi-thread chain stitch sewing machine with
the seam ravel preventing apparatus having the foregoing structure and ravel prevention
operation as described in detail above, namely, the improved structure employed in
the present invention in order to solve the problem remained unsolved in the already-filed
patent application of the present applicant is described below by focusing on Figs.
2 to 4.
[0088] As shown in Figs. 2 to 4, the needle plate base 11 attached to the upper surface
of the sewing machine bed B is divided into a left needle plate base 11L and a right
needle plate base 11R. The left needle plate base 11L has the needle plate P detachably
attached to the upper surface thereof via a set screw 100, and supports the support
shaft 30 as the center of swing of the thread hanging hook 3 of the needle thread
holding mechanism.
[0089] Screw holes 101 are formed at a plurality of front and rear portions (two portions)
in the vicinity of the left end part in the left needle plate base 11L, specifically,
at portions away from the attachment position of the needle plate P in the vicinity
of the front end (left end) of a sewing machine arm C indicated by a virtual line
in Fig. 4. The left needle plate base 11L is attached to the upper surface of the
sewing machine bed B so as to permit fastening and unfastening (attachment and detachment).
[0090] Further, as shown in Fig. 3, the upper surface of the sewing machine bed B and the
left needle plate base 11L are provided with knock pins 103 and pin holes 104 into
which the knock pins 103 fit, at positions away from two fastening positions via set
screw members 102. The pin holes 104 are inserted into and engaged with the knock
pins 103 from above, thereby positioning the left needle plate base 11L at predetermined
position and posture with respect to the sewing machine bed B. In this state, the
set screw members 102 are screwed into the screw holes 102, thereby allowing the left
needle plate base 11L to be fastened against the upper surface of the sewing machine
bed B.
[0091] Although the present embodiment describes and illustrates one in which the knock
pins 103 protrude upward from the upper surface of the sewing machine bed B, and the
pin holes 104 are formed in the left needle plate base 11L or, alternatively, the
knock pins 103 may protrude downward from the lower surface of the left needle plate
base 11L, and the pin holes 104 may be formed in the upper surface of the sewing machine
bed B.
[0092] On the other hand, the right needle plate base 11R constitutes a cylinder attachment
base for supporting the thread handling cylinder 32 and the stopper cylinder 42 (hereinafter
the right needle plate base 11R is referred to as the cylinder attachment base). The
foregoing stopper mechanism is disposed at a lower part of the cylinder attachment
base 11R. To be specific, as shown in Figs. 5 to 8, the thread handling cylinder 32
is fixedly supported on the lower surface of the cylinder attachment base 11R via
an attachment screw 105. The stopper cylinder 42 is disposed below the thread handling
cylinder 32 in a two-stage fashion, and the stopper cylinder 42 is fixedly supported
on the cylinder attachment base 11R via an attachment screw 106.
[0093] The cylinder attachment base 11R is installed in a fixed state to a side surface
of the sewing machine bed B via a set screw 107. The phrase "fixed state" denotes
the state in which the ravel preventing apparatus H is fixed to a predetermined position
by fastening the set screw member 107 when installing it into the sewing machine bed
B, and is fixed at a predetermined installation position after the installation without
performing any positional adjustment or the like.
[0094] One end (right end) portion of the connecting rod 35 is rotatably connected to the
stopper member 4 in the stopper mechanism by a pin screw 108. In a certain part of
the cylinder attachment base 11R which corresponds to a connecting part between the
one end of the connecting rod 35 and the stopper member 4 by the pin screw 108, a
long groove 109 that is long in a lateral direction is formed so as to allow for a
linear reciprocating movement of the stopper member 4 that linearly reciprocates in
the lateral direction in response to the expansion and contraction of the thread handling
cylinder 32.
[0095] A connection end portion 35a of the other end of the connecting rod 35, which is
connected to an extended part 3c connected to the thread hanging hook 3, is bent downward
in a depth corresponding to a substantial thickness of the extended part 3c. A pin
110 is protruded upward from the connection end portion 35a of the downward bent connecting
rod 35. On the other hand, the extended part 3c is provided with a connecting hole
111 that is insertable into the pin 110 from above the pin 110 and is drawable in
an upward direction. This eliminates the need to perform an operation for fixedly
connecting the connecting rod 35 and the extended part 3c, for example, releasing
an interlocking state between the two by unfastening a set screw or the like, when
the left needle plate base 11L is removed from the sewing machine bed B by unfastening
it from the sewing machine bed B. That is, the connecting hole 111 of the extended
part 3c can be drawn upward from the pin 110, and the interlocking state between the
connecting rod 35 and the extended part 3c (the thread hanging hook 3) can be released
only by raising the left needle plate base 11L. Also, when attaching the left needle
plate base 11L to the sewing machine bed B, only by an operation of shifting the left
needle plate base 11L from above toward the sewing machine bed B, the connecting hole
111 is inserted into the pin 110 from above, thereby allowing the connecting rod 35
and the extended part 3c (thread hanging hook 3) to return to the interlocking state.
The connection end portion 35a of the connecting rod 35 needs not necessarily be bent
downward. That is, the connecting rod 35 may have a flat plate shape.
[0096] A swing lever attachment base (movable base) 92, which supports the swing lever 9
in the stopper mechanism so as to be swingable around the vertically extending support
shaft 90, is attached to the cylinder attachment base 11R so as to permit lateral
position adjustment via a long hole 93 being long in a lateral direction and a set
screw 94. Accordingly, even after the cylinder attachment base 11R is installed in
the fixed state into the sewing machine bed B via the screw member 107, timing the
looper 1 slips out of the needle thread loop 20a held by the thread hanging hook 3
can be optionally adjusted by performing the lateral position adjustment of the swing
lever attachment base 92 with respect to the cylinder attachment base 11R. This ensures
the selflooping for the seam ravel prevention.
[0097] In the horizontal tube type multi-thread chain stitch sewing machine with the seam
ravel preventing apparatus H employing the structure having the foregoing characteristic
features, when the seam ravel preventing apparatus H is installed into the sewing
machine bed B, the left needle plate base 11L and the right cylinder attachment base
11R, which are obtained by dividing the needle plate base 11 into right and left sections,
can be individually attached to the sewing machine bed B. Hence, as compared with
handling of the single long and large needle plate as in the case of the technique
described in the already-filed patent application by the present applicant, the attachment
(installation) operation of the entirety of the ravel preventing apparatus H with
respect to the sewing machine bed B can be easily carried out with less effort.
[0098] Additionally, if after the needle plate base 11 (the left needle plate base 11L and
the right cylinder attachment base 11R) is installed into the sewing machine bed B,
it becomes necessary to adjust stitch performation by correcting the position and
motion loci of the components for performing sewing action which are located below
the needle plate base 11 and are stored inside the sewing machine bed B, such as the
looper 1 and actuating members therefor, or it becomes necessary to perform maintenance,
such as mending and replacement, on various types of components stored below the needle
plate base 11 and inside the sewing machine bed B, it is unnecessary to remove the
cylinder attachment base 11R by which the thread handling cylinder 32 and the stopper
cylinder 43 respectively having the air tubes 33 and 43 attached thereto are strongly
supported during the installation thereof. A sufficiently wide operating space can
be ensured only by unfastening and removing the left needle plate base 11L from the
sewing machine bed B.
[0099] Hence, the adjustment of sewing performation, and the maintenance such as the mending
and replacement on the various types of components stored inside the sewing machine
bed B can be performed extremely easily, simply, and efficiently only by handling
the small and lightweight left needle plate base 11L to which the air tubes 33 and
34 do not cling. Consequently, satisfactory sewing performation and the predetermined
ravel prevention function can constantly be exhibited with superior reproducibility,
thereby solving the problem remained unsolved in the already-filed patent application
by the present applicant.
[0100] The present embodiment employs the structure in which the swing lever 9 in the stopper
mechanism is swingingly energized by the spring 91 in the direction in which the thread
hanging hook 3 in the needle thread holding mechanism is positioned at the standby
position. Therefore, the action of the stopper member 4 in the return direction (the
action in the direction in which the thread hanging hook is positioned at the standby
position) is performed by the energizing force of the spring 9. This allows for employment
of a single-acting type air cylinder as the stopper cylinder 42 for actuating the
swing lever 9 that engages with or disengages from the part of the stopper member
4, thereby achieving downsizing and cost reduction of the stopper cylinder 42.
[0101] The present embodiment also employs the structure in which the thread handling cylinder
32 in the needle thread holding mechanism and the stopper cylinder 42 in the stopper
mechanism are fixedly supported on the lower surface of the cylinder attachment base
11R in the vertical two-stage fashion. Therefore, the planar space occupied by the
two air cylinders 32 and 42 can be reduced to permit compactness of the entirety of
the ravel preventing apparatus H, thereby allowing the ravel preventing apparatus
H to be nicely stored inside the sewing machine bed B, compared with the case where
the two air cylinders 32 and 42 are disposed at the positions separated from each
other (side-by-side arrangement) as in the case of the technique described in the
already-filed patent application by the present applicant.
[0102] The present embodiment further employs the structure for attaching the looper thread
holder 6 to the thread hanging hook 3 in the needle thread holding mechanism. The
looper thread holder 6 holds the looper thread extending from the looper 1 to the
fabric at a more forward position than the drop position of the needle 2 by swinging
together with the thread hanging hook 3 in the plane substantially parallel to the
needle plate P around the vertically extending support shaft 30 between the thread
hooking position, the hold position, and the standby position. This simple structure
can surely position the looper thread 10 together with the needle thread 20. Thereby,
the selflooping can be surely performed to further ensure the seam ravel prevention
effect.
[0103] Particularly, by position-adjustably attaching the looper thread holder 6 with respect
to the thread hanging hook 3, the relative positions of the needle thread 20 and the
looper thread 10 can appropriately be set, and the selflopping can be more surely
performed to further enhance the seam ravel prevention effect.
[0104] The present embodiment further employs the structure in which the pin 110 is protruded
upward from the connecting end portion 35a of the connecting rod 35, and the connecting
hole 111, which is insertable into the pin 110 from above the pin 110 and is upward
drawable, is formed at the connecting end portion (extended part 3c) closer to the
thread hanging hook 3. Therefore, when the left needle plate base 11L is unfastened
from the upper surface of the sewing machine bed B and is removed in an upward direction
from the sewing machine bed B in order to perform the adjustment of stitch performation
and the maintenance, such as the mending and replacement, on the various types of
components stored inside the sewing machine bed B, the thread hanging hook 3 and the
connecting rod 35 can be disengaged from each other only by raising the left needle
plate base 11L, without requiring any troublesome operation, such as unfastening and
removing the screw connecting the connecting rod 35 and the extended part 3c closer
to the thread hanging hook 3, or pulling-out of the connecting pin. Additionally,
after the adjustment and maintenance, the thread hanging hook 3 and the connecting
rod 35 can be returned to the predetermined connected state only by fastening the
left needle plate base 11L to the sewing machine bed B from above. This further saves
the labor in the adjustment and maintenance.
[0105] Although the foregoing embodiment has described the case of using the air cylinders
as the hook actuator and the stopper actuator, electromagnetic solenoids may be used
as these actuators.
[0106] Although the foregoing embodiment has also described the case of forming the multi-thread
chain stitch seams by the two needles 20 and 20 and the single looper thread 10, it
is applicable to one which forms multi-needle double chain stitch seams by using three
or more needle threads, or one which forms one-needle chain stitch seams by using
one needle thread, or a top-cover multi-thread chain stitch sewing machine which performs
top cover sewing on multi-thread chain stitch seams.
[0107] The foregoing embodiment has also described the case of performing the ravel prevention
in which one of the needle thread loops formed by the two needle threads 20 and 20
is caught and held at the hold position, and in this state, the sewing action for
one stitch is performed for selflooping. Alternatively, a plurality of needle thread
loops may be caught and held at the hold position, and the sewing action in the hold
state may be for two switches or more without being limited to one stitch.
[0108] The foregoing embodiment has also described the case where the looper thread holder
6 the thread hanging hook of the needle thread holding mechanism is preferably provided
with a looper thread holder which holds the looper thread extending from the looper
to a fabric at a more forward position than the drop position of the needle by swinging
together with the thread hanging hook around the support shaft in the plane substantially
parallel to the needle plate between the thread hooking position, the hold position,
and the standby position. Alternatively, the looper thread holder 6 and the thread
hanging hook 3 may be disposed separately and be individually operated by a dedicated
actuator different from the thread handling cylinder 32 for actuating the thread hanging
hook 3. Further alternatively, it is not essential to install the looper thread holder
6.
Industrial Applicability
[0109] The needle plate base is divided into the left and right sections, which are configured
to be individually handled as the left needle plate base and the right cylinder attachment
base. Hence, the attachment (installation) of the entirety of the ravel preventing
apparatus to the sewing machine bed, and the adjustment of sewing performation, and
the maintenance such as the mending and replacement on the various types of components
stored inside the sewing machine bed can be performed easily with less labor, thus
permitting a suitable application to the multi-thread chain stitch sewing machine.
Reference Signs List
[0110]
- 1
- looper
- 2
- needles
- 4
- stopper member
- 3
- thread hanging hook
- 6
- looper thread holder
- 8
- control section
- 9
- swing lever
- 10
- looper thread
- 11
- needle plate base
- 11L
- left needle plate base
- 11R
- cylinder attachment base (right needle plate base)
- 20
- needle thread
- 20a, 20b
- needle thread loops
- 30
- vertically extending support shaft
- 32
- thread handling cylinder (hook actuator)
- 35
- connecting rod (connecting member)
- 42
- stopper cylinder (stopper actuator)
- 91
- spring
- 92
- swing lever attachment base (movable base)
- 102
- screw members
- 103
- knock pin
- 104
- pin hole
- 110
- pin
- 111
- connecting hole
- A
- needle drop location
- B
- sewing machine bed
- P
- needle plate
- M
- multi-thread chain stitch seams
1. A multi-thread chain stitch sewing machine with a seam ravel preventing apparatus
wherein the multi-thread chain stitch sewing machine comprises a needle (2) moving
up and down while holding a needle thread (20); a looper (1) which is movable forward
and backward while holding a looper thread (10) in a direction substantially orthogonal
to a vertical movement path of the needle (2), and catches a needle thread loop (20a,
20b) formed below a needle plate (P) by the needle (2) during a forward movement;
and a needle plate base (11) having the needle plate attached thereto and being attached
to an upper surface of a sewing machine bed (B), and wherein the multi-thread chain
stitch sewing machine is configured to form multi-thread chain stitch seams (M) on
a fabric by allowing the looper (1) to catch the needle thread loop (20a, 20b) formed
below the needle plate (P) by the needle (2), and then by interlooping the needle
thread (20) with the looper thread (10) held by the looper (1), the multi-thread chain
stitch sewing machine with the seam ravel preventing apparatus comprising:
a needle thread holding mechanism comprising (i) a thread hanging hook (3) which is
approachable and departable with respect to the looper (1), and swings around a vertically
extending support shaft (30) in a plane substantially parallel to the needle plate
(P) between a standby position away from the looper (1) and a thread hooking position
close to the looper (1), and (ii) a hook actuator (32) for drivingly swinging the
thread hanging hook (3) to the standby position and the thread hooking position;
a stopper mechanism comprising (iii) a stopper member (4) which is disposed at a position
farther away from the needle plate (P) than the thread hanging hook (3) of the needle
thread holding mechanism, and permits temporary suspension and unsuspension of a swing
of the thread hanging hook (3) from the hooking position to the standby position so
that the needle thread loop (20a, 20b) caught by the thread hanging hook (3) at the
thread hooking position is held at a hold position between the thread hooking position
and the standby position, and (iv) a stopper actuator (42) for performing the suspension
and the unsuspension of the stopper member (4);
a connecting member (35) for interlockingly connecting the thread hanging hook (3)
of the needle thread holding mechanism and the stopper member (4) of the stopper mechanism;
and
a control section (8) which controls the needle thread holding mechanism and the stopper
mechanism in association with a vertical movement of the needle (2), forward and backward
movements of the looper (1), and feed of the fabric so that the looper (1) is moved
forward after the normal sewing is terminated and the thread hanging hook (3) of the
needle thread holding mechanism is brought near the looper (1), the needle thread
loop (20a, 20b) caught at the thread hooking position is moved to the hold position,
a resulting state is maintained until the needle (2) descends through the needle thread
loop (20a, 20b) caught by the looper (1), and thereafter, a sewing action for at least
one stitch is performed,
characterized in that the needle plate base (11) is divided into two sections: a left needle plate base
(11L) for attaching a needle plate (P) thereto and supporting the swinging support
shaft (30) of the thread hanging hook (3); and a right needle plate base (11R) for
fixedly supporting the stopper member (4) and the hook actuator (32) and the stopper
actuator (42), and
wherein the right needle plate base (11R) is fastened to the sewing machine bed (B),
and the left needle plate base (11L) is fastenably and unfastenably fastened to an
upper surface of the sewing machine bed (B) via screw members (102).
2. The multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to claim 1, further comprising:
a feed reducing mechanism (83) for feeding the fabric at a lower feed rate than during
a normal sewing under an operation command provided from the control section (8),
in the sewing action for the at least one stitch.
3. The multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to claim 1, further comprising:
a looper thread restraining mechanism (84) for restraining feed of the looper thread
(10) to the looper (1) under an operation command provided from the control section
(8), after the looper thread (10) is positioned ahead of or behind a drop position
of the needle (2).
4. The multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to claim 1, wherein the stopper mechanism comprises:
a stopper member (4) which is directly connected to the hook actuator (32) and moves
linearly reciprocally;
a swing lever (9) engageable with and disengageable from a part of the stopper member
(4);
a spring (91) for swingingly energizes the swing lever (9) in a direction in which
the thread hanging hook (3) is positioned at the standby position; and
the stopper actuator (42) for disengaging the swing lever (9) from the part of the
stopper member (4) against an energizing force of the spring (91).
5. The multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to claim 4, wherein the swing lever (9) in the stopper mechanism is attached
to a movable base (92) attached laterally position-adjustably to the right needle
plate base (11R).
6. The multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to claim 4, wherein the hook actuator (32) of the needle thread holding
mechanism and the stopper actuator (42) of the stopper mechanism are fixedly supported
on a lower surface of the right needle plate base (11R) in a vertical two-stage fashion.
7. The multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to claim 1, further comprising:
a looper thread holder (6) which holds the looper thread (10) extending from the looper
(1) to the fabric at a more forward position than the drop position of the needle
(2) by swinging together with the thread hanging hook (3) of the needle thread holding
mechanism around the support shaft in a plane substantially parallel to the needle
plate (P), between the thread hooking position, the hold position, and the standby
position; and
an actuator for swinging the looper thread holder (6).
8. The multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to claim 1, wherein the looper thread holder (6) is fastened together with
the thread hanging hook (3) of the needle thread holding mechanism so as to swing
integrally with the thread hanging hook (3) around the support shaft in the plane
substantially parallel to the needle plate (P), between the thread hooking position,
the hold position, and the standby position.
9. The multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to claim 8, wherein the looper thread holder (6) is attached position adjustably
to the thread hanging hook (3).
10. The multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to claim 1, wherein the hook actuator (32) of the needle thread holding
mechanism and the stopper actuator (42) of the stopper mechanism are both air cylinders.
11. The multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to claim 1, wherein a pin (110) is protruded upward from a connection end
portion (35a) of the connecting member (35), and a connection end portion of the thread
hanging hook (3) is provided with a connecting hole (111) that is insertable into
the pin (110) from above the pin (110), and is drawable in an upward direction.
12. The multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to claim 1, wherein the left needle plate base (11L) or the sewing machine
bed (B) is provided with protruding knock pins (103) which are capable of positioning
the left needle plate base (11L) to the sewing machine bed (B) at a plurality of positions
away from a plurality of fixedly connecting portions and connection release portions
by means of the screw members (102), and the sewing machine bed (B) or the left needle
plate base (11L) is provided with pin holes (104) engageable with the knock pins (103).
13. The multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to claim 1, wherein a target sewing machine is a horizontal tube type single
needle multi-thread chain stitch sewing machine.
14. The multi-thread chain stitch sewing machine with the seam ravel preventing apparatus
according to claim 1, wherein a target sewing machine is a horizontal tube type multi-needle
multi-thread chain stitch sewing machine.
1. Mehrfaden-Kettenstichnähmaschine mit einer Einrichtung zum Verhindern einer Nahtverwicklung,
wobei die Mehrfaden-Kettenstichnähmaschine eine Nadel (2), die sich auf und ab bewegt,
während sie einen Nadelfaden (20) hält; einen Greifer (1), der vorwärts und rückwärts
beweglich ist, während er einen Greiferfaden (10) in einer Richtung im Wesentlichen
orthogonal zu einem vertikalen Bewegungsweg der Nadel (2) hält und eine Nadelfadenschleife
(20a, 20b) einfängt, die unterhalb einer Nadelplatte (P) durch die Nadel (2) während
einer Vorwärtsbewegung gebildet wird; und eine Nadelplattenbasis (11) umfasst, die
eine Nadelplatte daran angebracht aufweist und die an einer oberen Oberfläche eines
Nähmaschinenbettes (B) angebracht ist, und wobei die Mehrfaden-Kettenstichnähmaschine
konfiguriert ist, um Mehrfaden-Kettenstichnähte (M) auf einem Stoff zu bilden, indem
ermöglicht wird, dass der Greifer (1) die Nadelfadenschleife (20a, 20b) einfängt,
die unterhalb der Nadelplatte (P) durch die Nadel (2) gebildet wird, und danach indem
der Nadelfaden (20) mit dem Greiferfaden (10), der von dem Greifer (1) gehalten wird,
umschlungen wird, wobei die Mehrfaden-Kettenstichnähmaschine mit der Einrichtung zum
Verhindern einer Nahtverwicklung umfasst:
einen Nadelfadenhaltemechanismus, umfassend (i) einen Fadenaufhängehaken (3), der
in Bezug auf den Greifer (1) zugänglich und entfernbar ist und um eine sich vertikal
erstreckende Stützwelle (30) auf einer Ebene im Wesentlichen parallel zur Nadelplatte
(P) zwischen einer Bereitschaftsposition weg von dem Greifer (1) und einer Fadeneinhakposition
nahe des Greifers (1) schwingt, und (ii) ein Hakenbetätiger (32) zum antreibenden
Schwingen des Fadenaufhängehakens (3) in die Bereitschaftsposition und die Fadeneinhakposition;
einen Stopper-Mechanismus, umfassend (iii) ein Stopper-Element (4), das an einer von
der Nadelplatte (P) weiter entfernten Position angeordnet ist als der Fadenaufhängehaken
(3) des Nadelfadenhaltemechanismus und vorübergehendes Aufhängen und Abhängen einer
Schwinge des Fadenaufhängehakens (3) von der Einhakposition in die Bereitschaftsposition
zulässt, so dass die Nadelfadenschleife (20a, 20b), die von dem Fadenaufhängehaken
(3) in der Fadenaufhängeposition eingefangen wird, in einer Halteposition zwischen
der Fadeneinhakposition und der Bereitschaftsposition gehalten wird und (iv) ein Stopper-Betätiger
(42) zum Durchführen der Aufhängung und der Abhängung des Stopper-Elements (4);
ein Verbindungselement (35) zum formschlüssigen Verbinden des Fadenaufhängehakens
(3) des Nadelfadenhaltemechanismus und des Stopper-Elements (4) des Stopper-Mechanismus;
und
einen Steuerabschnitt (8), der den Nadelfadenhaltemechanismus und den Stopper-Mechanismus
in Verbindung mit einer vertikalen Bewegung der Nadel (2), Vorwärts- und Rückwärtsbewegungen
des Greifers (1) und einem Vorschub des Stoffes derart steuert, dass der Greifer (1)
nach Abschluss des normalen Nähens vorwärts bewegt wird und der Fadenaufhängehaken
(3) des Nadelfadenhaltemechanismus in die Nähe des Greifers (1) gebracht wird, wobei
die Nadelfadenschleife (20a, 20b), die in der Fadenaufhängeposition eingefangen ist,
in die Halteposition bewegt wird, ein resultierender Zustand beibehalten wird, bis
die Nadel (2) durch die Nadelfadenschleife (20a, 20b), die von dem Greifer (1) eingefangen
wird, hinunterfährt und danach ein Nähvorgang für mindestens einen Stich durchgeführt
wird,
dadurch gekennzeichnet, dass die Nadelplattenbasis (11) in zwei Abschnitte unterteilt ist: eine linke Nadelplattenbasis
(11L) zum Anbringen einer Nadelplatte (P) daran und zum Stützen der schwingenden Stützwelle
(30) des Fadenaufhängehakens (3); und eine rechte Nadelplattenbasis (11R) zum festen
Abstützen des Stopper-Elements (4) und des Haken-Betätigers (32) und des Stopper-Betätigers
(42), und
wobei die rechte Nadelplattenbasis (11R) an dem Nähmaschinenbett (B) befestigt ist
und die linke Nadelplattenbasis (11L) an einer oberen Oberfläche des Nähmaschinenbettes
(B) über Schraubenelemente (102) befestigbar und lösbar befestigt ist.
2. Mehrfaden-Kettenstichnähmaschine mit der Einrichtung zum Verhindern einer Nahtverwicklung
nach Anspruch 1, weiter umfassend:
einen Vorschubverringerungsmechanismus (83) zum Vorschieben des Stoffes mit einer
geringeren Vorschubgeschwindigkeit als während eines normalen Nähens gemäß eines Bedienbefehls,
der von dem Steuerabschnitt (8) beim Nähvorgang für den mindestens einen Stich bereitgestellt
wird.
3. Mehrfaden-Kettenstichnähmaschine mit der Einrichtung zum Verhindern einer Nahtverwicklung
nach Anspruch 1, weiter umfassend:
einen Greiferfaden-Rückhaltemechanismus (84) zum Zurückhalten eines Vorschubs des
Greiferfadens (10) zum Greifer (1) gemäß eines Bedienbefehls, der von dem Steuerabschnitt
(8) bereitgestellt wird, nachdem der Greiferfaden (10) vor oder hinter einer Fallposition
der Nadel (2) positioniert wurde.
4. Mehrfaden-Kettenstichnähmaschine mit der Einrichtung zum Verhindern einer Nahtverwicklung
nach Anspruch 1, wobei der Stopper-Mechanismus umfasst:
ein Stopper-Element (4), das direkt mit dem Haken-Betätiger (32) verbunden ist und
sich linear hin und her bewegt;
einen Schwinghebel (9), der mit einem Teil des Stopper-Elements (4) in Eingriff und
außer Eingriff gebracht werden kann;
eine Feder (91) zum schwingenden Erregen des Schwinghebels (9) in einer Richtung,
in welcher der Fadenaufhängehaken (3) in der Bereitschaftsposition positioniert ist;
und
den Stopper-Betätiger (42) zum Außereingriffbringen des Schwinghebels (9) von dem
Teil des Stopper-Elements (4) gegen eine Erregungskraft der Feder (91).
5. Mehrfaden-Kettenstichnähmaschine mit der Einrichtung zum Verhindern einer Nahtverwicklung
nach Anspruch 4, wobei der Schwinghebel (9) in dem Stopper-Mechanismus an einer beweglichen
Basis (92) angebracht ist, die seitlich positionsverstellbar an der rechten Nadelplattenbasis
(11R) angebracht ist.
6. Mehrfaden-Kettenstichnähmaschine mit der Einrichtung zum Verhindern einer Nahtverwicklung
nach Anspruch 4, wobei der Haken-Betätiger (32) des Nadelfadenhaltemechanismus und
der Stopper-Betätiger (42) des Stopper-Mechanismus fest auf einer unteren Oberfläche
der rechten Nadelplattenbasis (11R) in vertikaler zweistufiger Weise abgestützt sind.
7. Mehrfaden-Kettenstichnähmaschine mit der Einrichtung zum Verhindern einer Nahtverwicklung
nach Anspruch 1, weiter umfassend:
einen Greiferfadenhalter (6), der den Greiferfaden (10), der sich vom Greifer (1)
zum Stoff erstreckt, in einer weiter vorwärtigen Position als die Fallposition der
Nadel (2) hält, indem er zusammen mit dem Fadenaufhängehaken (3) des Nadelfadenhaltemechanismus
um die Stützwelle auf einer Ebene im Wesentlichen parallel zur Nadelplatte (P) zwischen
der Fadeneinhakposition, der Halteposition und der Bereitschaftsposition schwingt;
und
einen Betätiger zum Schwingen des Greiferfadenhalters (6).
8. Mehrfaden-Kettenstichnähmaschine mit der Einrichtung zum Verhindern einer Nahtverwicklung
nach Anspruch 1, wobei der Greiferfadenhalter (6) zusammen mit dem Fadenaufhängehaken
(3) des Nadelfadenhaltemechanismus derart befestigt ist, um mit dem Fadenaufhängehaken
(3) um die Stützwelle auf einer Ebene im Wesentlichen parallel zu der Nadelplatte
(P) zwischen der Hakenhalteposition, der Halteposition und der Bereitschaftsposition
einteilig zu schwingen.
9. Mehrfaden-Kettenstichnähmaschine mit der Einrichtung zum Verhindern einer Nahtverwicklung
nach Anspruch 8, wobei der Greiferfadenhalter (6) positionsverstellbar an dem Fadenaufhängehaken
(3) angebracht ist.
10. Mehrfaden-Kettenstichnähmaschine mit der Einrichtung zum Verhindern einer Nahtverwicklung
nach Anspruch 1, wobei der Haken-Betätiger (32) des Nadelfadenhaltemechanismus und
der Stopper-Betätiger (42) des Stopper-Mechanismus beide Luftzylinder sind.
11. Mehrfaden-Kettenstichnähmaschine mit der Einrichtung zum Verhindern einer Nahtverwicklung
nach Anspruch 1, wobei ein Stift (110) von einem Verbindungsendabschnitt (35a) des
Verbindungselements (35) nach oben vorragt und ein Verbindungsendabschnitt des Fadenaufhängehakens
(3) mit einem Verbindungsloch (111) bereitgestellt ist, das von oberhalb des Stifts
(110) in den Stift (110) einführbar ist, und in eine Aufwärtsrichtung gezogen werden
kann.
12. Mehrfaden-Kettenstichnähmaschine mit der Einrichtung zum Verhindern einer Nahtverwicklung
nach Anspruch 1, wobei die linke Nadelplattenbasis (11L) oder das Nähmaschinenbett
(B) mit vorstehenden Schlagstiften (103) bereitgestellt ist, welche die linke Nadelplattenbasis
(11L) mit dem Nähmaschinenbett (B) an einer Vielzahl von Positionen weg von einer
Vielzahl von feststehenden Verbindungsabschnitten und Verbindungslöseabschnitten mittels
der Schraubenelemente (102) positionieren können und wobei das Nähmaschinenbett (B)
oder die linke Nadelplattenbasis (11L) mit Stiftlöchern (104) bereitgestellt sind,
die mit den Schlagstiften (103) in Eingriff gebracht werden können.
13. Mehrfaden-Kettenstichnähmaschine mit der Einrichtung zum Verhindern einer Nahtverwicklung
nach Anspruch 1, wobei eine Zielnähmaschine eine horizontale Einnadel-Mehrfaden-Kettenstichnähmaschine
vom Röhrentyp ist.
14. Mehrfaden-Kettenstichnähmaschine mit der Einrichtung zum Verhindern einer Nahtverwicklung
nach Anspruch 1, wobei eine Zielnähmaschine eine horizontale Mehrnadel-Mehrfaden-Kettenstichnähmaschine
vom Röhrentyp ist.
1. Machine à coudre à point de chaînette multifils ayant un appareil de prévention d'effilochure
de couture, dans laquelle la machine à coudre à point de chaînette multifils comprend
une aiguille (2) se déplaçant vers le haut et le bas tout en retenant un fil d'aiguille
(20) ; un boucleur (1) qui est mobile en avant et en arrière tout en retenant un fil
de boucleur (10) dans une direction sensiblement orthogonale à un trajet de déplacement
vertical de l'aiguille (2) et capture une boucle de fil d'aiguille (20a, 20b) formée
en dessous d'une plaque à aiguille (P) par l'aiguille (2) au cours d'un mouvement
en avant ; et une base de plaque à aiguille (11) à laquelle la plaque à aiguille est
fixée et qui est fixée à une surface supérieure d'une base de machine à coudre (B),
et dans laquelle la machine à coudre à point de chaînette multifils est configurée
pour former des coutures à point de chaîne multifils (M) sur un tissu en permettant
au boucleur (1) de capturer la boucle de fil d'aiguille (20a, 20b) formée en dessous
de la plaque à aiguille (P) par l'aiguille (2) et ensuite en entrelaçant le fil d'aiguille
(20) avec le fil de boucleur (10) retenu par le boucleur (1), la machine à coudre
à point de chaînette multifils avec l'appareil de prévention d'effilochure de couture
comprenant :
un mécanisme de suspension de fil d'aiguille comprenant (i) une boucle de suspension
de fil (3) qui peut être rapprochée et éloignée du boucleur (1) et oscille autour
d'un arbre de support s'étendant verticalement (30) dans un plan sensiblement parallèle
à la plaque à aiguille (P) entre une position de réserve écartée du boucleur (1) et
une position d'accrochage de fil proche du boucleur (1) et (ii) un actionneur de crochet
(32) pour faire osciller en service le crochet de suspension de fil (3) dans la position
de réserve et dans la position d'accrochage de fil ;
un mécanisme d'arrêt comprenant (iii) un élément d'arrêt (4) qui est disposé dans
une position encore plus éloignée de la plaque à aiguille (P) que le crochet de suspension
de fil (3) du mécanisme de retenue de fil d'aiguille et permet une suspension et une
dé-suspension temporaires d'un mouvement oscillant du crochet de suspension de fil
(3) de la position d'accrochage à la position de réserve de sorte que la boucle de
fil d'aiguille (20a, 20b) capturée par le crochet de suspension de fil (3) dans la
position d'accrochage de fil soit maintenue dans une position de maintien entre la
position d'accrochage de fil et la position de réserve, et (iv) un actionneur d'arrêt
(42) pour effectuer la suspension et la dé-suspension de l'élément d'arrêt (4) ;
un élément de liaison (35) pour relier de manière verrouillable le crochet de suspension
de fil (3) du mécanisme de retenue de fil d'aiguille et l'élément d'arrêt (4) du mécanisme
d'arrêt ; et
une section de commande (8) qui commande le mécanisme de retenue de fil d'aiguille
et le mécanisme d'arrêt en association avec un mouvement vertical de l'aiguille (2),
des mouvements vers l'avant et l'arrière du boucleur (1) et l'alimentation du tissu
de sorte que le boucleur (1) soit déplacé en avant une fois que la couture normale
est terminée et que la boucle de suspension de fil (3) du mécanisme de retenue de
fil d'aiguille soit amenée près du boucleur (1), que la boucle de fil d'aiguille (20a,
20b) capturée dans la position d'accrochage de fil soit déplacée dans la position
de retenue, qu'un état résultant soit maintenu jusqu'à ce que l'aiguille (2) descende
à travers la boucle de fil d'aiguille (20a, 20b) capturée par le boucleur (1) et qu'ensuite,
une action de couture pour au moins un point soit effectuée,
caractérisée en ce que la base de plaque d'aiguille (11) est divisée en deux sections : une base de plaque
à aiguille de gauche (11L) pour y fixer une plaque à aiguille (P) et supporter l'arbre
de support oscillant (30) du crochet de suspension de fil (3) ; et une base de plaque
à aiguille de droite (11R) pour supporter de manière fixe l'élément d'arrêt (4) et
l'actionneur de crochet (32) et l'actionneur d'arrêt (42), et
dans lequel la base de la plaque à aiguille de droite (11R) est fixée à la base (B)
de la machine à coudre et la base de la plaque à aiguille de gauche (11L) est fixée
de manière solide et indétachable à une surface supérieure de la base (B) de la machine
à coudre via des éléments à vis (102).
2. Machine à coudre à point de chaînette multifils avec l'appareil de prévention d'effilochure
de couture selon la revendication 1, comprenant en outre :
un mécanisme de réduction d'alimentation (83) pour alimenter le tissu à un débit d'alimentation
inférieur à celui d'une couture normale dans le cadre d'une commande opératoire fournie
par la section de commande (8), dans l'action de couture pour le au moins un point.
3. Machine à coudre à point de chaînette multifils avec l'appareil de prévention d'effilochure
de couture selon la revendication 1, comprenant en outre :
un mécanisme de limitation de fil de boucleur (84) pour limiter l'alimentation du
fil de boucleur (10) au boucleur (1) dans le cadre d'une commande opératoire fournie
par la section de commande (8) une fois que le fil de boucleur (10) est positionné
devant ou derrière une position de chute de l'aiguille (2).
4. Machine à coudre à point de chaînette multifils avec l'appareil de prévention d'effilochure
de couture selon la revendication 1, dans laquelle le mécanisme d'arrêt comprend :
un élément d'arrêt (4) qui est directement relié à l'actionneur de crochet (32) et
se déplace en va- et-vient de manière linéaire ;
un levier oscillant (9) qui peut s'engager sur une partie de l'élément d'arrêt (4)
et s'en dégager ;
un ressort (91) pour soumettre à une oscillation le levier oscillant (9) dans une
direction dans laquelle le crochet de suspension de fil (3) est positionné en position
de réserve ; et
l'actionneur d'arrêt (42) faisant en sorte de dégager le levier oscillant (9) de la
partie de l'élément d'arrêt (4) à l'encontre d'une force d'excitation du ressort (91).
5. Machine à coudre à point de chaînette multifils avec l'appareil de prévention d'effilochure
de couture selon la revendication 4, dans laquelle le levier oscillant (9) du mécanisme
d'arrêt est fixé à une base mobile (92) fixée latéralement en position de manière
ajustable à la base de plaque à aiguille de droite (11R).
6. Machine à coudre à point de chaînette multifils avec l'appareil de prévention d'effilochure
de couture selon la revendication 4, dans laquelle l'actionneur de crochet (32) du
mécanisme de retenue de fil d'aiguille et l'actionneur d'arrêt (42) du mécanisme d'arrêt
sont supportés de manière fixe sur une surface inférieure de la base de plaque à aiguille
de droite (11R) en mode vertical à deux étages.
7. Machine à coudre à point de chaînette multifils avec l'appareil de prévention d'effilochure
de couture selon la revendication 1, comprenant en outre :
un support de fil de boucleur (6) qui retient le fil de boucleur (10) s'étendant du
boucleur (1) sur le tissu dans une position plus avancée que la position de chute
de l'aiguille (2) par oscillation conjointe avec le crochet de suspension de fil (3)
du mécanisme de retenue de fil d'aiguille autour de l'arbre de support dans un plan
sensiblement parallèle à la plaque à aiguille (P), entre la position d'accrochage
de fil, la position de retenue et la position de réserve ; et
un actionneur pour faire osciller le support de fil de boucleur (6).
8. Machine à coudre à point de chaînette multifils avec l'appareil de prévention d'effilochure
de couture selon la revendication 1, dans laquelle le support de fil de boucleur (6)
est fixé conjointement avec le crochet de suspension de fil (3) du mécanisme de retenue
de fil d'aiguille de manière à le faire osciller intégralement avec le crochet de
suspension de fil (3) autour de l'arbre de support dans le plan sensiblement parallèle
à la plaque à aiguille (P), entre la position d'accrochage de fil, la position de
retenue et la position de réserve.
9. Machine à coudre à point de chaînette multifils avec l'appareil de prévention d'effilochure
de couture selon la revendication 8, dans laquelle le support de fil de boucleur (6)
est fixé dans une position réglable par rapport au crochet de suspension de fil (3).
10. Machine à coudre à point de chaînette multifils avec l'appareil de prévention d'effilochure
de couture selon la revendication 1, dans laquelle l'actionneur de crochet (32) du
mécanisme de retenue de fil d'aiguille et l'actionneur d'arrêt (42) du mécanisme d'arrêt
sont tous deux des cylindres pneumatiques.
11. Machine à coudre à point de chaînette multifils avec l'appareil de prévention d'effilochure
de couture selon la revendication 1, dans laquelle une goupille (110) fait saillie
vers le haut d'une partie d'extrémité de liaison (35a) de l'élément de liaison (35)
et une partie d'extrémité de liaison du crochet de suspension de fil (3) est dotée
d'un trou de liaison (111) qui peut être enfilé dans la goupille (110) par-dessus
la goupille (110) et peut en être retiré dans une direction ascendante.
12. Machine à coudre à point de chaînette multifils avec l'appareil de prévention d'effilochure
de couture selon la revendication 1, dans laquelle la base de plaque à aiguille de
gauche (11L) ou la base (B) de la machine à coudre est pourvue de goupilles saillantes
(103) qui sont capables de positionner la base de la plaque à aiguille de gauche (11L)
sur la base (B) de la machine à coudre dans une pluralité de positions s'écartant
d'une pluralité de parties de liaison fixe et de parties de libération de liaison
au moyen d'éléments filetés (102) et la base (B) de la machine à coudre ou la base
de la plaque à aiguille de gauche (11L) est dotée de trous de goupilles (104) qui
peuvent s'engager sur les goupilles (103).
13. Machine à coudre à point de chaînette multifils avec l'appareil de prévention d'effilochure
de couture selon la revendication 1, dans laquelle une machine à coudre cible est
une machine à coudre à point de chaînette multifils à aiguille unique du type à tube
horizontal.
14. Machine à coudre à point de chaînette multifils avec l'appareil de prévention d'effilochure
de couture selon la revendication 1, dans laquelle une machine à coudre cible est
une machine à coudre à point de chaînette multifils à aiguilles multiples du type
à tube horizontal.