BACKGROUND OF THE INVENTION
[0001] The present invention relates to a synchronous yarn feeding device for a textile
machine.
[0002] As is known in the art, yarn is delivered by means of a yarn feeding drum and a driving
belt. Fig. 11 illustrates a typical conventional yarn feeding device. The drum 1 having
a plurality of round bars 3 formed with a cage-shaped periphery is rotatably mounted
on a yarn guide frame 5. A belt 2 presses the yarn 9 onto the smooth outer periphery
of the drum, thereby continuing the yarn feeding operation by frictional force. On
frame 5 a pair of porcelain eyes 8 are mounted for guiding the incoming yarn and the
outgoing yarn, respectively. Eyes 8 guide the incoming yarn F or outgoing yarn under
pressure of belt 2 so that the yarn can be fed on or off the drum.
[0003] A drawback of pair art yarn feeding apparatus is that instability and inaccuracies
may be introduced into the yarn feeding operation. As the amount of yarn fed on the
drum is increased, the contact surface between the belt and the drum is decreased
and the contact surface becomes irregular. Therefore, the driving belt 2 will have
a different effect on the speed of the turning drum for each drum that it is in contact
with. Moreover, these differences are not easily perceived by the operator, and thus
connot be corrected by adjusting any conventional means. The quality of weaved cloth
is therefore degraded. Yarn breakage is increased and the profitability of production
is decreased.
SUMMARY OF THE INVENTION
[0004] Therefore, an object of the present invention is to provide a synchronous yarn feeding
device, which enables the rotation speed of each yarn feeding drum, the yarn feeding
speed and the driving speed of belt to be synchronized, thereby making uniform the
feeding speed and tension of each of the yarn strands pressed on each of respective
yarn feeding drums by the same belt.
[0005] A further object of the present invention is to provide a synchronous yarn feeding
drum with an elastic body whereby the elasticity of said elastic body yields a relatively
larger contacting surface for the yarn and a less slippery surface so that the yarn
feeding operation will be more stable and accurate.
[0006] Othere objects and advantages of the present invention will become evident from the
following description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007]
Fig. 1 is a front view of the first embodiment according to the present invention;
Fig. 2 is an illustrative diagram showing the use of the device of Fig. 1;
Fig. 3 is a front view of the second embodiment according to the present invention;
Fig. 4 shows a front view and a cut-away view of the third embodiment according to
the present invention;
Fig. 5 is a perspective view of the fourth embodiment according to the present invention;
Fig. 6 is a representative cross-sectional view of the embodiments of the present
invention;
Fig. 7 is a front view of the fifth embodiment according to the present invention;
Fig. 8 is a front view of the sixth embodiment according to the present invention;
Fig. 9 is an exploded view of the embodiment in Fig. 8;
Fig. 10 is a cut-away view taken along line 10 - 10 of Fig. 8;
Fig. 11 shows a front view of a yarn feeding device of the prior art.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0008] For the purpose of easy cross reference between the description of each of the preferred
embodiments of the invention, the same reference labels are used to designate similar
components of the various embodiments of the present invention.
[0009] The basic components of the synchronous yarn feeding device of the present invention
comprise a yarn feeding drum, a driving belt, a yarn guiding frame, an incoming yarn
guide eye and an outgoing yarn guide eye. For the purpose of simplicity, the yarn
guiding frame and outgoing yarn guide eye are omitted in the drawings and description.
[0010] While the preferred embodiments of the present invention include projections or protrusions
on the drum and corresponding holes or slots on the belt, alternate positioning/driving
means can be provided on the drum or belt. For example, studs could be provided on
the belt and holes provided in the drum. The important concept is that a first portion
on the outer periphery of the drum is synchronously driven by the endless driving
belt with the aid of the positioning/driving means on both the drum and belt. In this
manner, the yarn feeding drum of the present invention functions as a conventional
driving pulley to drive the drum in addition to performing the function of feeding
yarn. The drum of the present invention is directly and synchronously driven by the
endless driving belt so that the yarn wound on the drum and further pressed thereon
by the driving belt will be fed in synchronism with the driving speed of the driving
belt with the aid of the driving/positioning means on the drum and belt.
[0011] Referring to Figs. 1 and 2, a first embodiment of the present invention is illustrated.
A yarn feeding drum 10 is rotatably mounted on a frame (not shown), and includes a
plurality of round bars 14, an upper cover 12, a lower cover 15 and a linking shaft
11. Drum 10 is provided with a solid cylinder 100 arranged within the round bars 14.
A plurality of positioning /driving means in the form of protrusions or studs 13 is
located on a first portion of the outer periphery of cylinder 100 near the upper cover
12. Each of the protrusion 13 is interposed between every two round bars 14 on a first
portion 101 of cylinder 100 located at the upper part of the yarn feeding drum 10.
The drum 10 is driven by belt 20 that includes a first portion of the upper part of
belt 20 with a corresponding positioning/driving means in the form of holes 21. Each
of the protrusions or studs 13 is sequentially engaged by holes 21. Yarn feeding drum
10 is thereby driven synchronously with driving belt 20.
[0012] As shown in Fig. 2, in the yarn feeding operation, yarn 30 is guided through a guiding
eye 40 to a second portion 102 of the yarn feeding drum 10 and is pressed onto drum
portion 102 by a second porton 22 of the driving belt 20. Yarn feeding drum 10 is
driven synchronously with belt 20 as previously described. Yarn 30, pressed between
second portions 22 and 102, is thereby driven forward synchronously with the belt
20, thus achieving the goal of precise yarn feeding. When the yarn is not being fed
or is being unwound, the yarn guiding eye 40 is displaced downward, as shown in the
dashed lines 40 of Fig. 2. Yarn 30 will not be pressed by the second portion 22 of
driving belt 20 in this position, and the yarn will slide along a third portion 103
of the yarn feeding drum 10, as shown in dashed line 30 in Fig. 2.
[0013] An alternative embodiment of the yarn feeding drum 10 is illustrated in Fig. 3. As
shown, the outer periphery of the drum, rather than including a plurality of round
bars, is made solid, as indicated at 100A. A plurality of studs 13 is arranged along
a first portion thereof.
[0014] Fig. 4 illustrates a third embodiment of the present invention, wherein the outer
periphery of the yarn feeding drum 10 has a sawtooth configuration indicated at 100B.
A plurality of protrusions or studs 13 is disposed on the periphery of the drum 10
and achieve the same goal as the protrusions or studs described above.
[0015] A fourth embodiment of the present invention is illustrated in Fig. 5. A plurality
of projections 13A is formed on a first portion of the drum 10. A first portion of
a belt 20 is formed with a plurality of repsective cutout slots 21A, whereby the slots
21A engage the projections 13A of the drum with the yarn 30 being pressed between
a second portion 22 of the belt 20 and a second portion 102 of the drum to enable
precise feeding of yarn.
[0016] Fig. 6 illustrates the cooperation between the positioning/driving means on both
the drum and the belt. A first portion 101 of the drum is provided with a plurality
of equally spaced protrusions 13. The protrusions are sequentially engaged by respective
holes or slots in driving belt 20, thus enabling the drum 10 to rotate synchronously
with belt 20. Yarn 30 is pressed upon the outer periphery of the drum 10 by driving
belt 20 and thus fed synchronously with the drum 10 and belt 20 to provide a precisely
fed supply of yarn.
[0017] A fifth embodiment of the present invention is shown in Fig. 7. A driving belt 20
is provided with a plurality of projections 21B. The plurality of projections 21B
is equally spaced by distance 210. The driving belt 20 is thereby configured to cooperate
with a cage-shaped drum 10 whereby each of the projections 21B fits into a corresponding
space between each two of the round bars in the drum 10. Thus, rotation of drum 10
and delivery of the yarn are synchronous with movement of driving belt 20.
[0018] Figs. 8 to 10 illustrate a sixth embodiment of the present invention. In order to
provide a relatively larger and slip resistant contact surface on drum 10 for the
yarn, a resilient body 50 is disposed to cover the second portion 102 of the drum.
In the embodiment shown in Figs. 8 to 10, the second portion 102 of the outer periphery
of the drum 10 is provided with a resilient body 50 such that the resilient body,
while being contacted by driving belt 20, will become flatter and thinner, thus providing
a relatively large contact surface with driving belt 20. Thus, the contact surface
between yarn 30 and the outer periphery of the drum 10 will be larger and more slip
resistant. The resilient body 50 can be formed with a plurality of protruding portions
51 interposed with a plurality of concave portions 52, as shown in Figs. 9 and 10.
[0019] The resilient body 50 is shown with the drum 10 of the second embodiment shown in
Fig. 3. Other embodiments of drum 10 may also be arranged with the same resilient
body 50, if desired.
[0020] Fig. 10 illustrates the yarn feeding arrangement in which the apparatus of the embodiment
of Figs. 8 and 9 are employed. Slipping or movement of the yarn 30 is inhibited by
the contact of yarn 30 with the protruding portions 51 of body 50. Contact with portions
51 increases the stability and precision of the yarn feeding operation that is synchronous
with the rotation of drum 10.
[0021] Fig. 9 illustrates a detailed construction of the sixth embodiment of the present
invention. A plurality of protrusions 13 is provided on upper disk 12 below which
are disposed a plurality of grooves 18 on body 111. A bearing 114 is inserted into
a central opening (not shown) in upper cover 12. A resilient body 50 fits around the
outer periphery of body 111. A plurality of protruding walls 57 located within the
inner surface of resilient body 50 fits into grooves 18 of body 111. A plurality of
protruding poles 16 on a lower disk 15 fits into respective holes (not shown) on the
upper disk 12, thereby fixing the upper and lower disks together. The upper surface
of a third portion 103 of disk 12 engages resilient body 50. Resilient body 50 is
thereby bound between the upper and lower disks 12 and 15. An easily manufactured
and firmly constructed synchronous yarn feeding drum is thereby provided.
[0022] In summary, the present invention provides a synchronous yarn feeding device with
a drum comprising a positioning/driving means including, for example, a plurality
of equally-spaced protrusions, and a belt comprising a positioning/driving means including,
for example, a plurality of respective holes. The yarn is pressed upon a second portion
of the drum and is fed in synchrnoization with the rotation of the yarn feeding drum
and the driving belt. The productivity of textile machines and the quality of product
are both greatly enhanced.
[0023] It is to be understood that the embodiments shown in the drawings and described herein
are examples of the teachings of the present invention. Other variations may be made
by those skilled in the art without departing from the spirit and scope of the present
invention.
1. A yarn feeding device for use in a textile machine, said textile machine including
a machine body and a frame fixed on said body, said yarn feeding device comprising:
a drum rotatably mounted on siad frame;
a yarn guiding means movably mounted beside said drum on said frame;
a driving belt; wherein
said drum including an outer periphery with a first protion having a first rigid projecting
engaging means for engaging a corresponding portion of said driving belt, a second
drum portion for receiving a portion of yarn being fed onto said drum, and a third
drum portion for receiving a portion of yarn being unfed from said drum when said
yarn guiding means is operativly moved torward said third portion of said drum; and
said driving belt including a first belt portion having a second engaging means for
cooperative engagement with said drum first portion and said first engaging means,
and a second belt portion for pressing a portion of yarn against said drum second
portion as a portion of yarn is fed onto said drum, whereby said yarn is fed onto
said drum in synchronism with the rotation of said drum and said driving belt, wherein
said first and second engagement means cooperate to maintain the position of said
belt second portion relative to said drum second portion while said yarn is being
fed onto said drum.
2. A yarn feeding device according to claim 1, wherein said first engaging means comprises
a plurality of protruding surfaces and said second engaging means comprises a plurality
of engaging concave surfaces for complementary engagement with said protruding surfaces
of said first engaging means.
3. A yarn feeding device according to claim 1, wherein said first engaging means comprises
a plurality of studs and said second engaging means comprises a plurality of holes
for complementary engagement with said studs.
4. A yarn feeding device according to claim 1, wherein said second portion of said
drum outer periphery comprises a plurality of protrusions interposed with a plurality
of grooves aligned with said driving belt to receive a portion of yarn and to feed
said yarn from said belt.
5. A yarn feeding device according to claim 1, wherein said second portion of said
drum outer periphery comprises a substantial round surface.
6. A yarn feeding device according to claim 1, wherein said second portion of said
drum outer periphery comprises a rough surface whereby slippage of said yarn on said
surface is inhibited.
7. A yarn feeding device according to claim 1, wherein said second portion of said
drum outer periphery comprises an elastic body.
8. A yarn feeding device according to claim 1, wherein said second portion of said
drum outer periphery comprises a body having a plurality of convex and concave portions.
9. A yarn feeding device according to claim 1, wherein said outer periphery of said
drum comprises a plurality of round bars and said first engaging means comprises a
plurality of protrusions interposed between said round bars and projecting out of
said drum outer periphery.
10. A yarn feeding device according to claim 3, wherein a front portion of each of
said studs is tapered.
11. A yarn feeding device according to claim 3, wherein said holes are provided at
one longitudinal side of said driving belt with respect to the driving direction of
said driving belt.
12. A yarn feeding device according to claim 3, wherein said studs are provided on
an upper side of said drum outer periphery.
13. A yarn feeding device according to claim 1, wherein said first engaging means
and said second engaging means are cooperatively locked each other in an axial direction
with respect to the drum so as to provide substantially even surface to surface contact
between the inner surface of the belt and the outer surface of the drum during a yarn
feeding operation.