Background Art In general, a fabric manufactured by using a shuttleless loom is woven by repeating steps of shedding warp threads utilizing ascending and descending motions of a heald and inserting woof threads between the shed warp threads and simultaneously battening the woof threads using a body until a fabric is completed.

During shedding, a catch cord yarn disposed at an opposite side of a woof thread supply portion picks and holds an end portion of the inserted woof thread. A leading end portion of the woof thread held by the catch cord yarn is cut by a cutting machine and then disposed of.

The catch cord yarn can be shed by using various means.

When the structure of a fabric is simple so that a small number of healds is used, the catch cord yarn can be shed by using two healds. However, when the structure of a fabric is complicated so that a large number of healds is used, an additional device for shedding the catch cord yarn is needed.

When an additional two heald for shedding of a catch cord is used to manufacture a simple fabric, even through a small number of healds is used, since an additional moving mechanism needs to be coupled to a Dobby machine for the shedding of a catch cord, In this case, many parts of the Dobby machine are rapidly worn, and moreover, expensive parts are needed for two harnesses (heald frames) and a driving portion needs to be used for four catch cord yarns. All these increase a manufacturing cost and power consumption.

Due to the above problems, even when a fabric having a relatively simple structure is to be woven, a fabricating means having an additional catch cord yarn

moving mechanism to shed only the catch cord yarn is widely used.

FIG. 1 shows an example of a conventional catch cord yarn moving mechanism.

The catch cord yarn moving mechanism shown in FIG. 1 has the following structure.

A bracket 13 is fixed to a frame (not shown) of a loom and a fixed piece 14 is provided at the center of the bracket 13. A first fixed shaft 11 is fixed on the fixed piece 14 and an eccentric cam 12 and a drive gear 10 are rotatably installed on the first fixed shaft 11.

A second fixed shaft 16 is installed in the upper portion of the bracket 13. An upper lever 18, to which an upper separator gear 17 is assembled, is coupled to the second fixed shaft 16 by using a bolt 19. A contact roller 20 is installed at the upper center end of the upper lever 18 and contacts an outer circumferential surface of the eccentric cam 12.

As shown in FIG. 2, a fixed pipe body 23 is installed at a position confronting the second fixed shaft 16 of the bracket 13. A rotary pipe body 33 is inserted in the fixed pipe body 23. One side of a lower lever 22 is fixedly coupled to an outer surface of the rotary pipe body 33. An end portion of the lower lever 22 is connected to an end portion of the upper lever 18 through a connection arm 21. A spring 25 connects the central portion of the upper lever 18 and a fixing pin 26 at the lower end of the bracket 13 so that the contact roller 20 elastically contacts the outer circumferential surface of the eccentric cam 12.

A rotation shaft 24 is installed inside the rotary pipe body 33, as shown in FIG. 2.

A lower separator gear 27 is mounted on in the rotation shaft 24 to be engaged with the upper separator gear 17 and then fixed by using a bolt 28.

Shed levers 30 and 31 are fixed to end portions of the rotary pipe body 33 and the rotation shaft 24, respectively. A thread hole 29 is formed in the shed levers 30 and 31 and a catch cord yarn (not shown) is inserted therein.

An operation of the mechanism for shedding a catch cord yarn using the catch cord yarn shed motion device is described below.

When the loom is operated, the drive gear 10 and the eccentric cam 12 are rotated by a crank shaft (not shown). The contact roller 20 operates as the eccentric cam 12 rotates so that the upper lever 18 fixedly coupled to the second fixed shaft 16 is moved up and down. Then, as the upper lover 18 moves up and down, the lower lever

22 connected to the connection portion 21 is moved up and down around the rotary pipe body 33.

As the upper lever 18 rotationally moves up and down around the first fixed shaft 16, the upper separator gear 17 coupled to the first fixed shaft 16 rotates.

Simultaneously, the lower separator gear 27 engaged with the upper separator gear 17 rotates and thus the rotation shaft 24 rotates. The rotary pipe body 33 inserted in the fixed pipe body 23 and the rotation shaft 24 rotate in different directions by the rotational up/down movement of the lower lever 22. Thus, the shed levers 30 and 31 coupled to the end portions of the rotary pipe body 33 and the rotation shaft 24 are moved up and down in different directions so that the catch cord yarn is shed.

However, the catch cord yarn moving mechanism having the above structure has the following problems.

Since the motion of the contact roller 20 is transferred to the shed levers 30 and 31 not directly but through many intermediary parts, an accurate shed motion transfer of the catch cord yarn is not possible.

The motion transfer is especially aggravated after a long time use of the mechanism when clearances between the intermediary parts, in particular, between the upper and lower separator gears 17 and 27 and connection portions of the shed levers 30 and 31, become larger. Accordingly, the amount of shed motion of the catch cord yarn by the shed levers 30 and 31, that is, the width of the shed, decreases so that it is difficult for the catch cord yarn to hold the inserted woof thread.

In the catch cord yarn shed motion device having the above structure, clearance is severely generated in a portion where the upper and lower separator gears 17 and 27 are engaged with each other and a connection portion of each lever.

That is, since the coupling of the upper and lower separator gears 17 and 27 is essential for the operation of the mechanism, shedding of the catch cord yarn is not properly performed.

Also, since the upper lever 18 is elastically supported by the spring 25 in one direction, the connection arm 21 connected thereto and a connection portion of the upper and lower separator gears 17 and 27 and the lower lever 22 are elastically supported in the same direction, the clearances are further enlarged so that many problems occur in the shed motion transfer of the catch cord yarn. Furthermore, since the shafts of the two shed levers are placed coaxially and constitute a dual shaft, even

when the two shafts wear slightly, the clearances between them is amplified by each other's motion so that the amount of shed motion is remarkably decreased.

Also, the structure of the shed motion device is complicated so that manufacturing of the same is difficult. Additionally, the use of the dual shaft makes an oil injection operation difficult, which limits lubrication of the dual shaft, thereby increasing noise and wear thereof. Also, since oil needs to be frequently injected, maintenance of the shed motion device is difficult.

Disclosure of the Invention To solve the above problems, the present invention provides a catch cord yarn shed motion device which has a simplified structure to decrease the effect of clearances between parts on the shed motion, and reduces a manufacturing cost.

Also, the present invention provides a catch cord yarn shed motion device which accurately transfers a motion of an eccentric cam to a catch cord yarn, smoothly makes a shed, makes holding of a woof thread easy, and enables a high speed motion appropriate to a high speed rotation loom.

According to an aspect of the present invention, a shed motion device of a catch cord yarn for a shuttleless loom, the shed motion device comprising a bracket, a cam assembly rotatably installed on the bracket and having a drive gear rotated by a crank shaft of the loom and an eccentric cam rotated by the drive gear, first and second rotation shafts rotatably installed on the bracket, first and second shed levers having end portions fixed to the first and second rotation shafts, respectively, first and second operation levers fixed to the first and second rotation shafts, respectively, a contact roller provided at one end of the first operation lever and contacting an outer circumferential surface of the eccentric cam, a guide roller installed on the bracket to be separated a predetermined distance from the first and second operation levers, an operation belt having both ends respectively connected to ends of the first and second operation levers and circulating around the guide roller, and rotating the second operation lever around the second rotation shaft in an opposite direction to a direction in which the first operation lever rotates, as the first operation lever pivots, and an elastic member provided between any two of the first operation lever, the second operation lever, and the bracket, to return the first and second operation levers.

The elastic member has one end coupled to the bracket and other end coupled

to the first or second operation lever.

The elastic member has one end coupled to the first operation lever and other end coupled to the second operation lever.

The contact portions of the first and second operation levers contacting the operation belt are formed to respectively have predetermined curvatures around the first and second rotation shafts.

Brief Description of the Drawings FIG. 1 is a side view of a conventional catch cord yarn shed motion device; FIG. 2 is a sectional view of a portion of a rotation shaft and a rotation shaft pipe of FIG. 1; FIG. 3 is a perspective view of a catch cord yarn shed motion device according to a preferred embodiment of the present invention; FIG. 4 is a side view of the catch cord yarn shed motion device of FIG. 3; FIG. 5 is a side view illustrating the major portion of the catch cord yarn shed motion device of FIG. 3, wherein a return spring is omitted, in which a contact roller contacts a lower portion of an eccentric cam so that shed levers are in an open position; FIG. 6 is a side view illustrating the major portion of the catch cord yarn shed motion device of FIG. 3, wherein a return spring is omitted, in which a contact roller contacts a middle portion of an eccentric cam so that shed levers are in a closed position; FIG. 7 is a side view illustrating the major portion of the catch cord yarn shed motion device of FIG. 3, in which a contact roller contacts a high portion of an eccentric cam so that a shed lever is open, wherein a return spring is omitted; FIG. 8 is a perspective view illustrating the major portion of the catch cord yarn shed motion device of FIG. 3; FIG. 9 is a side view of a catch cord yarn shed motion device according to another preferred embodiment of the present invention; FIG. 10 is a side view of a catch cord yarn shed motion device according to yet another preferred embodiment of the present invention; and FIG. 11 is a view illustrating a second operational lever according to an embodiment of the present invention.

Best Mode for Carrying out the Invention Hereinafter, a preferred embodiment of the present invention is described in detail with reference to the accompanying drawings.

A catch cord yarn shed motion device 100 according to a preferred embodiment of the present invention is typically installed in a shuttleless loom in a position opposite to a woof thread supply portion, and holds an end portion of a woof thread which is inserted through a shed made by opening and closing a catch cord yarn disposed at one side of a warp thread.

First, as shown in FIG. 3, the catch cord yarn shed motion device 100 according to a preferred embodiment of the present invention includes a bracket 200, a cam assembly 240 rotatably installed on the bracket 200, first and second rotation shafts 250 and 251 installed on the bracket 200 at a predetermined distance from each other, first and second shed levers 255 and 256 fixed to the first and second rotation shafts 250 and 251, respectively, first and second operation levers 252 and 253 fixed to the first and second rotation shafts 250 and 251, respectively, a contact roller 260 provided at one end of the first operation lever 252, a guide roller 212 installed on the bracket 200 to be separated a predetermined distance from the first and second operation levers 252 and 253, and an operation belt 259 circulating around the guide roller 212, both ends of the operation belt 259 being respectively connected to end portions of the first and second operation levers 252 and 253. The operation belt 259 makes the second operation lever 253 pivot around the second rotation shaft 251 in a direction opposite to the direction in which the first operation lever 253 pivots.

The bracket 200 includes a main bracket 201 installed on a frame (not shown) of a loom, a connection bracket 210 coupled to a lower portion of the main bracket 201 using a bolt 211, and a pair of auxiliary brackets 220 coupled to one side of the connection bracket 210 using the bolt 221.

A fixed piece 202 is provided in an upper portion of the main bracket 201. A fixed shaft 203 is installed in the fixed piece 202, as shown in FIG. 2. A fixing bolt 204 is coupled to the fixed piece 202 so that the fixed shaft 203 is fixed to the fixed piece 202.

A cam assembly 240 is rotatably installed at one end of the fixed shaft 203.

The cam assembly 240 includes an eccentric cam 230 and a drive gear 241 coupled to

each other. The eccentric cam 230 is eccentrically rotated by the drive gear 241.

The drive gear 241 is rotated by a crack shaft (not shown) of the loom. Here, a rotation ratio of the drive gear 241 to the crack shaft may be 1: 2. A slot 231 is formed in the eccentric cam 230 so that a positional angle of the eccentric cam 230 can be arbitrarily adjusted as necessary.

A fixed arm 205 is fixed to the fixed piece 202 of the main bracket 201. A first hook rod 206 protrudes from one side of the fixed arm 205, to which one end of a return spring 262, i. e. , an elastic member, is connected.

The guide roller 212 is rotatably installed on an inner surface of the connection bracket 210, which will be described later.

The first and second rotation shafts 250 and 251 are rotatably installed at the auxiliary brackets 220 assembled to one side of the connection bracket 210. The first and second operation levers 252 and 253 are fixed to one side of each of the first and second rotation shafts 250 and 251. The first and second shed levers 255 and 256 having thread holes 254 are fixed to the other side of each of the first and second rotation shafts 250 and 251. As the first and second operation levers 252 and 253 pivot, the first and second rotation shafts 250 and 251 are rotated so that the first and second shed levers 255 and 256 move up and down to cross each other.

Both ends of the operation belt 259 are respectively fixed to the ends of the first and second operation levers 252 and 253. The operation belt 259, as shown in FIG. 5, is provided to circulate around the guide roller 212 installed inside the connection bracket 210. A general belt material can be used for the operation belt 259.

The contact roller 260 in addition to the operation belt 259 is installed at one end of the first operation lever 252. The contact roller 260 contacts and rolls over an outer circumferential surface of the eccentric cam 230. The contact roller 260 rotatably installed at one end of the first operation lever 252 transfers a motion of the eccentric cam 230 to the first operation lever 252.

When the motion of the eccentric cam 230 is transferred to the first operation lever 252 via the contact roller 260, the first operation lever 252 pivots clockwise or counterclockwise around the first rotation shaft 250. The second operation lever 253 connected to the first operation lever 252 by the operation belt 259 pivots around the second rotation shaft 251 counterclockwise or clockwise in the opposite direction of the first operation lever.

As the first and second operation levers 252 and 253 pivot, the first and second rotation shafts 250 and 251 respectively fixed to the first and second operation levers 252 and 253 rotate. According to the present invention, since the first and second rotation shafts 250 and 251 are supported to contact only a portion of the auxiliary bracket 220, even if the first and second rotation shafts 250 and 251 and the portion of the auxiliary bracket 220 supporting the rotation shafts wear considerably, the amount of shed of the first and second shed levers 255 and 256 can be always constant.

In the present invention, the first and second operation levers 252 and 253 are returned by an additional elastic member. The elastic member can be connected between any two members among the bracket 200, the first operation lever 252, and the second operation lever 253.

According to the preferred embodiment shown in FIGS. 3 through 8, the elastic member is connected between the bracket 200 and the second operation lever 253.

That is, one end of a return spring 262, which is an elastic member, is fixed to the first hook rod 206 of the fixed arm 205 installed on the fixed piece 202 of the main bracket 201. A second hook rod 261 is formed on the second operation lever 253 so that the other end of the return spring 262 is fixed to the second hook rod 261. Then, the end portion of the second operation lever 253 is always pulled upward and accordingly, the second operation lever 253 and the first operation lever 252 can be returned to the original state. In addition to the elastic member, a rubber member or other elastic member can be used as an elastic member to provide a return force to the operation levers.

The elastic member can be installed in various manners. As shown in FIG. 9, the second hook rod 261 is installed at the side portion of the connection bracket 210 while the first hook rod 206 is installed at the end portion of the first operation lever 252.

The return spring 262 can be connected between the connection bracket 210 and the first operation lever 252. As shown in FIG. 10, the first hook rod 206 and the second hook rod 261 are installed on the first operation lever 252 and the second operation lever 253, respectively, and the return spring 262 can be connected between the first and second operation levers 252 and 253.

In the operation of the catch cord yarn shed motion device having the above structure, when the drive gear 241 is rotated and the contact roller 260 contacts the outer circumferential surface of the eccentric cam 230, as shown in FIG. 5, the first

shed lever 255 and the second shed lever 256 are disposed up and down to be wide open.

In this state, as the eccentric cam 230 continuously rotates, the contact roller 260 is separated from the fixed shaft 202 by an eccentricity ratio. Accordingly, the first operation lever 252 pivots counterclockwise, as shown in FIG. 6. As the first operation lever 252 pivots, the first rotation shaft 250 rotates counterclockwise and the first shed lever 255 pivots counterclockwise so that the end portion of the first shed lever 255 is moved downward.

When the first operation lever 252 pivots, the second operation lever 253 connected to the first operation lever 252 by the operation belt 259 pivots clockwise in the opposite direction to the first operation lever 252 and simultaneously the second rotation shaft 251 rotates clockwise. As the second rotation shaft 251 rotates, the second shed lever 256 pivots around the second rotation shaft 251 so that the end portion of the second shed lever 256 is moved upward. As a result, the first and second shed levers 255 and 256 are closed such that the thread holes 254 overlap each other to close the catch cord yarn.

When the eccentric cam 230 continuously rotates in this state, as shown in FIG.

7, a maximum radial portion of the eccentric cam 230 contacts the contact roller 260.

In this state, since the first operation lever 252 pivots counterclockwise around the first rotation shaft 250 at its maximum, the first rotation shaft 250 remains in a maximum rotated state, thereby firmly maintaining closure of the shed levers 255 and 256.

When the first operation lever 252 pivots at its maximum, the operation belt 259 is pulled upward as well. Accordingly, the second operation lever 253 connected to an end portion of the operation belt 259 via the guide roller 212 pivots clockwise around the second rotation shaft 251. Thus, the interval between the first and second operation lever 252 and 253 increases so that the return spring 262 connected thereto is extended.

Simultaneously, the first and second shed levers 255 and 256 fixed to the first and second rotation shafts 250 and 251 are open, as shown in FIG. 7, to shed the catch cord yarn.

In the above state, a woof thread is inserted through the catch cord yarn and the completely inserted woof thread is held therein when the catch cord yarn is closed.

These motions are repeated so that a fabric is woven.

When the insertion of the woof thread in the catch cord yarn open by the first and second shed levers 255 and 256 as shown in FIG. 7 is completed, the drive gear 241 and the eccentric cam 230 continue to rotate. The contact roller 260 escapes from the maximum radial portion of the eccentric cam 230 and contacts a lower portion thereof. In this state, as the first and second operation levers 252 and 253 which are open by the return spring 262 are returned to the original state, the first and second shed levers 255 and 256 are closed so that the woof thread inserted between the catch cord yarn is completely held. When the eccentric cam 230 rotates in this state, the first and second shed levers 255 and 256 are open and accordingly the catch cord yarn is open. The operation of inserting and holding the woof thread is repeated so that the fabric is woven.

In the opening/closing operation of the first and second shed levers 255 and 256 for the catch cord yarn shed motion according to the present invention, since the contact roller 260 installed at the first operation lever 252 elastically contacts the eccentric cam 230, and the first operation lever 252 is directly fixed to the first rotation shaft 250 which is fixed to the first shed lever 255, the motion of the contact roller 260 by the rotation of the eccentric cam 230 is directly transferred via the first rotation shaft 250 without any loss in the amount of motion. Also, since the second shed lever 256 is fixed to the second rotation shaft 251, and the second operation lever 253 is installed at the other end of the second rotation shaft 251 while the second operation lever 253 is connected by the operation belt 259 circulating around the guide roller 212, the eccentric motion of the eccentric cam 230 can be accurately transferred.

In particular, to make the first and second shed levers 255 and 256 move the same distance and prevent the operation belt 259 from vibrating during a high speed operation, as shown in FIG. 11, contact portions 257 and 258 of the operation belt 259 disposed at the end portions of the first and second operation levers 252 and 253 are formed to have a predetermined curvature R around the first and second rotation shafts 250 and 251, respectively. Although only the second operation lever 253 is shown in the drawing, the first operation lever 252 has the same shape as the second operation lever 253.

Therefore, since the distance between the first and second shed levers 255 and 256 can be maintained within a predetermined range by the eccentric cam 230, an operation of the shed motion device is not affected by a gradual increase of clearances

between parts, thereby preventing the amount of shedding of the catch cord yarn from decreasing, and accordingly, holding the woof thread can be smoothly performed.

As described above, the present invention has the following advantages.

First, since clearance between the parts moving during a shedding operation can be maintained within a predetermined range, an accurate amount of shedding can be obtained.

Second, a high speed operation is possible owing to a smooth motion.

Third, wear and vibrations of the shed motion device can be minimized by controlling the clearances between the parts.

Fourth, since the motion of the eccentric cam is directly transferred to the first and second shed levers, the motion of the eccentric cam is accurately transferred so that accurate shedding of the catch cord yarn is possible.

Fifth, since a high speed rotation is easily possible, productivity in weaving a fabric can be improved.

Sixth, since the structure of a shed motion device is simple and fabric weaving can be made rapidly and easily, a production cost can be reduced.

Seventh, maintenance of the shed motion device is easy.

Eighth, since the contact portions disposed at the end portions of the first and second operation levers are formed to have a predetermined curvature, vibration of the operation belt can be reduced so that a quiet operation and high speed operation are possible.

Industrial Applicability The present invention concerns a shed motion device for shedding a catch cord varn and can be used for a loom for weaving a fabric.