INVENTION'S DATA
[0001] The purpose of the present Letters Patent application relates to certain developments
brought in a zigzag and transporting motion for sewing machines which provides essential
characteristics in newness as compared with similar systems known and used to the
same purpose. More specially this invention is aimed to the featuring of a zigzag
motion operated by means of two single engines of the kind known as stepper motors
and accurately synchronized each other in order to obtain the desired results.
[0002] Capabilities of accuracy and control offered by stepper motors have determined the
fast spreading of them and their application to the most diverse engineering fields.
In the concrete field of the sewing machines there are now at the market some models
which feature this kind of engine for the performing of some specific operation.
A SHORT DESCRIPTION OF DEVICE
[0003] Developments which are the object of the present invention have foreseen the use
of two stepper motors by means of which and through adequate media it is provided
in an independent manner the zigzag movement of needle and advance of propelling gear.
Therefor, driving shaft of a first stepper motor gears up a rack which by an end couples
itself with the end of a lever cranked at some points and pivotable in relation of
one of said elbowing points, which at its opposite end also fastens itself in an articulated
manner to the supporting part of the needle's bar. The above supporting piece fits
by its upper end with pivoting capability in relation with its fastening point.
[0004] Second stepper motor gears up its driving axle with a rack which induces a change
in the operation, as from its mean point, of a connecting rod which by its upper side
keeps a permanen contact to an eccentric thanks to action of a tension spring, such
an accentric being driven by the operation of the main motor of the machine while
by its lowest end accounts on a driving shaft for the forward and back motion of the
carrying means of the machine, setting out such an axle by virtue of the oscillating
motion of connecting rod, an arch which larger or smaller amplitude depends on the
said raid positioning and which in turn translates itself into a larger or smaller
displacement of said conveyor means.
[0005] Controlled actuation of both stepper motors named above shall be performed through
electronic media and preferably by means of a microprocessor.
A BRIEF DESCRIPTION OF DEVICE
[0006] Detailed description of the invention subject which follows shall refer notwithstanding
to the enclosed drawings where by way of example and without limiting character therefore
a preferred form of realization is displayed. By these drawings:
Figure 1 shows an elevational view in section, of a sewing machine which features
the developments which are the subject of the invention.
Figure 2 shows a ground-plant view of the sewing machine shown by the Figure 1.
Figure 3 illustrates a face elevation view of a cross section made at the sewing machine
of Figure 1 in the proximity of the position of the stepper motor which drives the
conveyor mechanism of the machine.
[0007] Referring firstly to Figure 1, it can be seen thereat an elevational view of a longitudinal
section made by a sewing machine which features the developments which are the subject
of this invention. By this Figure it can be seen a first stepper motor marked with
numerical reference 1 and a second stepper motor marked with numerical reference
2. Driving shaft 3 of motor 1 operates a reack piece 4 hinged at an end with a middle
piece 5, which owns its opposite end likewise hinged with a lever 6 cranked by different
points along its length. Said lever 6 fastens itself pivotably to machine chassis
by one of its points 7 of elbowing and it has its free end clamped also pivotably,
preferably by means of a screw 9 to a piece 8 of supporting of the bar 10 of the
needle. Rack piece 4 is driven by its reciprocating travel by means of stubs 11 bored
in openings made thereat.
[0008] Second motor 2 has its driving shaft 12 connected to a rack piece 13 through a middle
piece 14 allowing this way shifting of positioning of connecting rod 15. Upper end
of said connecting rod 15 finds itself urged by the traction of a spring 16, then
said connecting rod leans itself permanently against an eccentric 17 linked with
a shaft 18 which gets motion from the main motor 19 of the machine by means of a belt
or another type of transmission.
[0009] Connecting rod 15 is interlocked by its lowest end to an horizontal axle 20 by virtue
of which oscillating movement of said connecting rod transforms itself into a travel
forward and back motion of the carrying device of the machine. Obviously this oscillating
movement of connecting rod 15 takes place around shaft 14' of the middle piece 14.
[0010] Shaft 22, driven by the main motor 19 of machine prefarably by means of a belt must
provide to carrying device 21 in a known manner the lifting and lowering motion.
[0011] At Figura 2 is represented a view of ground-plant of machine as per Figura 1 where
different components are shown of which constitutes the subject of invention and
relative position kept thereamong. Thus it can be seen the connecting rood 15 which
rests by its upper side on eccentric 17 fastened to shaft 18, being able such axle
18 to operate, in a known manner, different organs of the machine; position of stepper
motors 1 and 2 and their associated elements and upper clamping of support piece 8
for the needle bar 10 assured by a short axle 23 in relation of which it can pivot.
[0012] By Figura 3 it can be seen a cross section drawn by the machine in the proximity
of the position of the second stepper motor 2. By said Figure may be perfectly seen,
position, shape and operation of the different elements associated to said motor 2.
This way it can be seen the rack piece 13 geared up the driving axle of the motor
2 and shiftable by it, fastened by the lowest side to the end of a middle piece 14
which opposite end hinges to connecting rod 15. Likewise it may be seen the spring
16 which exerts traction on the upper end of said connecting rod 15 to keep it permanently
resting on the peripheric surface of eccentric 17. On the lower side said connecting
rod 15 is connected to carrying device by means of shaft 20.
[0013] Driving of both motors 1 and 2 shall be independent as above quoted, and shall be
controlled by electronic means. These electronic means can be known or not, and able
to be programmed for the operation in the time of both motors 1 and 2 according to
results which attainment should be desirable.
[0014] According to above, motor 1 shall be used to provide a zigzag motion to machine needle.
Therefor said stepper motor duly controlled by the electronic means shall provide
to rack 4 a reciprocating movement to be transmitted through the middle piece 5 to
the end related to cranked lever 6, which opposite end is hinged joint through screw
9 to support 8 of the needle bar. This way reciprocating motion of rack 4 becomes
the zigzag movement desired for the needle.
[0015] This embodiment has the advantage that by means of a minor number of simple elements
is possible to come to end the zigzag effect of the needle. It is understandable that
a larger or smaller amplitude of the reciprocating motion of rack 4 translates itself
respectively in a larger or smaller width of zigzag; then if duly regulated every
moment the travel of rack 4 it can be obtained a predetermined shape of zigzag.
[0016] Stepper motor 2 is in charge of regulating the shifting limits of travelling device
of the machine. In fact the above travelling device is subject to the combination
of two movements, i.e., one of lifting-lowering and other of forward-back motion.
Lifting-lowering movement is provided in a known manner as above quoted by shaft 22
driven by the main motor of the machine. Forward-back motion is operated by shaft
20 when actuating on such travelling device 21 when driven in turn by the connecting
rod 15.
[0017] The movement of the shaft 20 is bent-shpaed, of larger or smaller amplitude according
to the position adopted by the rack 13. According to Figures 1 and 3, after connecting
machine to network, starts motion of shaft 18 which hauls eccentric 17 communicating
a reciprocicating motion to the upper end of the connecting rod 15 and taking place
pivoting of that in relation of axle 14' by means of which is connected to middle
piece 14. Lowest end of connecting rod draws an arch centered at shaft 14' of pivoting
and which amplitude depends on distance between pivoting shaft 14' and the contact
point between connecting rod 15 and eccentric 17. For the position shown at Figure
3, arch run by the lowest end of the connecting rod 15 (and also by axle 20) shall
have a defined amplitude which translates itself in a concrete shifting of the carrying
device. Notwithstanding, actuating on motor 2 shall change the position of rack 13
and consequently connecting rod shall be shifted altering the distance existing between
shaft 14' of pivoting and the contact point of connecting rod 15 and eccentric 17
resulting in a variation of the amplitud of the arch drawn by the lowest end of connecting
rod 15 and by axle 20 resulting in a larger or smaller travelling of carrying device,
as the case may be.
[0018] Advantage of this embodiment is that only is necessary to use a reduced number of
simple components in order to provide to the carrying device for a forward-back travelling.
It must be understood that when operating properly on the said stepper motor 2 either
by programming or by any other means it is possible to regulate on time the shifting
of carrying device, if desired.
[0019] Effect of combined regulation of both stepper motors 1 and 2 by means of programming
or by any other proper means allows obtaining on fabrics any kind of figure or drawing
desired.
[0020] Invention have been described according to a preferred embodiment of same. It must
be realized notwithstanding that within its essentiality might be introduced multiple
variations of detail likewise protected which could effect its shape, size or manufacturing
materials of assembly or its parts without altering at all the object of the invention.
1.- Developments brought in a zigzag and transport device for sewing machines characterized
by the foreseeing of the embodying of two stepper motors, one of them aimed to performing
of zigzag and width regulation of same, and the other assigned to move and regulate
shifting of carrying device of the machine, in order to which, the said first stepper
motor gears up its driving shaft in a first rack, trained by means of stubs housed
in openings made thereat, which through a middle piece induces reciprocating movement
to the end of a crankinglever which has its opposite end pivotably connected to the
resting piece of the needle bar, while the second stepper motor has its driving shaft
geared up likewise with a second rack connected to an end of its middle piece and
to which opposite end pivotably clamps itself a connecting rod which has its upper
end urged to traction by a spring for permanently resting on an accentric interlocked
to an axle driven by the main motor of the machine while the lowest end of said connecting
rod is provided with an axle which when operating on the carrying device of machine
causes its shifting.
2.- Developments according to claim 1 characterized because the variation of limits
of reciprocating motion of the said first rack induces the variation of the zigzag
width attained by the needle of the machine.
3.- Developments according to claims 1 and 2 characterized because the variation of
positioning of the said second rack shall induce likewise variation in the height
of said connecting rod being consequently modified likewise the width of arch run
by the lowest end of connecting rod and associated shaft and moreover the limits of
shifting of the machine carrying device.