US3311137A - Shuttle-less loom reciprocating mechanism - Google Patents

Description

March 28, 1967 MlANGOLARRA 3,311,137

SHUTTLE-LESS LOOM RECIPROCATING MECHANISM Filed 001;. 23, 1964 3 Sheets-Sheet 2 INVENTOR. fiQ/VC/SCO MANGOLA A United States Patent C) 3,311,137 SHUTTLE-LESS 1.00M RECIPROCATING MECHANISM Francisco Miangolarra, San Isidro, a San Julian 5, Caracas, Venezuela Filed Oct. 23, 1964, Ser. No. 405,934 1 Claim. (Cl. 139-422) This invention relates generally to textile weaving machines, and more particularly to a reciprocating mechanism for a shuttle-less loom which is adapted to introduce filling yarns into the fabric at a high rate of speed.

Weaving is a process by which two systems of yarns are interlaced at right angles to produce a textile fabric. The warp yarns, that is, those running the length of the fabric, are prepared by rewinding yarns from yarn packages, such as cones or cheeses, onto warp beams. These yarns, after being suitably sized to prevent chafing in the loom, are drawn through the eyes of needles, which are fine steel wires suspended from frames on the loom and called harnesses. The harnesses are arranged simultaneously to raise or lower the warp yarns associated therewith.

In the making of plain-weave fabrics, only two harnesses are required. The first, third, fifth, and all other odd-number warp yarns are threaded through the needles of one harness, whereas the second, fourth, sixth, and all even-number warp yarns are threaded through the needles of the second harness. In the weaving process, one harness is raised while the other is depressed, thereby raising half of the warp yarns and lowering the other half to create a tunnel therebetween known as a shed. The filling or weft thread, which in the fabric runs transversely with respect to the warp threads, is ordinarily driven through the shed by means of a shuttle. This is a boatlike device containing the filling yarn, leaving the filling thread in its wake.

After the shuttle is driven through the shed, the weft thread is beaten against the finished fabric by a movable comb-like frame or reed. The position of the harnesses is then reversed, and the shuttle is driven back, again depositing filling yarn. This back-and-forth motion of the shuttle, alternating with the raising and lowering of the harnesses and coordinated With the action of the reed, is repeated continuously and rapidly. Many commercial types of looms are capable of weaving-in 180 filling yarns per minute, or of producing five yards per hour of a fabric having 60 picks (filling yarns) to the inch.

One major drawback in the use of shuttles resides in the fact that the amount of thread that is containable within the shuttle is relatively small, and in fast looms it is used up in a few minutes; hence the loom must be frequently halted to replace the shuttle. Even if the change of shuttle takes only a few seconds, there is a loss of productivity. For example, if the shuttle makes 180 crosses per minute, and a shuttle change takes only a few seconds, for each of these seconds, three crosses are lost.

Attempts have been made to do away with shuttles by inserting the filling yarn by means of reciprocating arms which cooperate with large spools of yarn, to thereby substantially reduce the number of stops required to replenish the yarn supply. The reciprocal movement of such arms is complicated by the fact that in introducing the filling at a high speed, the holder must quickly accelerate to pull the yarn across the fabric and then slow down and stop at a desired positon for a given interval, two such stops being necessary for each weft crossing. Since after the Weft is in place it must be beaten against the fabric, the holder must dwell until this action is completed.

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What is required, therefore, is a reciprocating mechanism which is adapted to dwell for a predetermined period sufiicient to allow the inserted Weft to be beaten into position, then quickly accelerate to pull in the next weft, the arm then slowing down and stopping for a shorter period to permit the pulled-in weft to be transformed before it returns quickly to its initial position.

While these actions can be carried out by cam or lever mechanisms, such mechanisms are relatively complex and inefficient as Well as being noisy in operation, and they are incapable of realizing the high speed possibilities inherent in shuttle-less loom operations.

Accordingly, it is the main object of this invention to provide a loom with reciprocating arms which are capable of operating effectively and reliably at high speed Without noise or vibration.

More specifically, it is an object of this invention to provide a mechanism for reciprocating pull-in and pullout filling yarn arms at high speed and for causing said arms to dwell at the end of the forward stroke for a period which is different from the dwell time at the end of the reverse stroke, thereby coordinating the operation of the reciprocating arms with the other functioning elements of the loom.

A significant advantage of the invention is that it makes it possible to operate looms without shuttles, with a con siderable reduction in the number of stops due to changes of yarn spool, and to provide well above filling traversals per minute in fabrics having a 70 cm. width. In fact, it now has become feasible when using the invention to carry out as many as 400 filling traversals per minute. Thus the loom, in accordance with the invention, requires less attention than conventional looms, and one weaver is able to supervise the operation of a large number of looms.

For a better understanding of the invention, as well as other objects and further features thereof, reference is made to the following detailed description to be read in conjunction with the accompanying drawing, wherein:

FIG. 1 schematically illustrates the reciprocating arms in accordance with the invention, in one position of the arms in the course of a filling yarn cycle;

FIG. 2 shows a second position of the arms in the course of the cycle;

FIG. 3 shows a third and final position of the yarn arms in the course of the cycle;

FIG. 4 is an elevational view of the reciprocating mechanism in accordance with the invention;

FIG. 5 is a top plan view of said mechanism; and

FIG. 6 diagrammatically shows the orbital path of travel of the follower pin and the resultant reciprocal motion of the carriage.

Referring now to FIG. 1, the shuttle-less filling yarn system in accordance with the invention is shown schematically, the system being adapted to interweave weft or filling yarns 10 with warp yarns 11 to produce a fabric web 12. In the interest of simplicity, the other components of the loom including the harnesses for raising and lowering the warp yarns and the reeds or combs for beating in the weft yarns, are not shown, for these loom elements are entirely conventional.

Filling yarns are introduced through, the warp yarn shed by means of two arms 13 and 14, positioned on opposite sides of the fabric web 12, the arms being arranged to move alternately toward and away from each other in the horizontal plane. Filling yarn F is supplied by a large spool S. The operation is such that the filling yarn, the end of which is grasped by the head 16 of the arm 13 at one side of the web, is pulled in by arm 13 across the fabric web to a point Y, midway therein, at which point the filling yarn is transferred to the head 17 of the arm 14, and pulled from point Y to the other side of the web,

the filling yarn then being cut at the input side of the web to complete the weft.

One full cycle of operation is shown in FIGS. 1, 2 and 3. The reciprocating movement of arms 13 and 14 is produced by mechanisms 18 and 19 to be later described in detail. At the beginning of the cycle, as shown in FIG. 1, the end of yarn F is held in the head 16 of arm 13, both arms 13 and 14 being in their fully retracted positions at the sides of the fabric web. Both arms 13 and 14 are then advanced toward each other to meet at the midpoint Y of the web, at which point the end of yarn F, which has been pulled thereto within the shed of warp yarns, is quickly transferred to the head 1'7 of arm 14. This situation, which occurs at the midpoint of the cycle, is shown in FIG. 2. The brief time it takes to effect this transfer is hereinafter referred to as the transfer interval.

Both arms 13 .and 14-then reverse direction and return to their initial retracted position, in the course of which movement, arm 13, whose head 16 is disengaged from yarn F, returns to the input side of the web and arm 14, which now holds the end of yarn F, pulls this yarn to the other side of the web, thereby completing the deposit of the yarn. Then, as shown in FIG. 3, yarn F is cut by blade K to detach the laid-in weft from the yarn F, and the. new end of the yarn F'is grasped by the head 16 in readiness for the next cycle. Before the next cycle commences, the weft W is beaten-in by the comb, in the usual manner, and the warp harnesses are reversed. The time for these actions to take place is hereinafter referred to as the cycle changeover interval.

The cycle changeover interval is necessarily somewhat more prolonged than the transfer interval, hence it is necessary that the reciprocating mechanisms which actuate arms 13 and 14'be capable of rapidly accelerating these arms from their retracted positions shown in FIG. 1, to the midpoint position Y, where the arms are slowed down and reversed during the relatively short transfer interval, the arms then rapidly returning to their retracted positions where they must remain for the longer cycle changeover interval.

To accomplish this purpose effectively, the reciprocating mechanisms in accordance with the invention are constituted, as shown in FIGS. 4 and 5, by a large sprocket wheel 20, a smaller sprocket wheel 21, an endless chain belt 22 intercoupling the two wheels, a carriage 23 horizontally slidable along a trackway, and a follower pin 24 connected to the chain 22 and extending into an elongated vertical slot 25 formed in the carriage. The arrangement is such that as the chain travels the orbital path formed by the sprocket wheels, the pin is caused to move accordingly, the pin at the same time compelling the carriage to undergo a reciprocal motion during which the pin position shifts up and down within the slot 25.

Carriage 23 reciprocates between two pairs of tracks, an upper track constituted by parallel rails 26, and a lower track constituted by parallel rails 27; The ends of the carriage are terminated in shoes 28 and 29 which ride slidably on the rails. The follower pin 24 connected to the chain 22 and extending through slot 25 in the carriage, is linked thereto by means of a slide formed by shoes 30 and 31 which ride vertically up and down the carriage.

The sprocket wheel 21 is supported in suitable hearings on a standard 32, while the sprocket wheel 20 is supported on a standard 33, both standards being attached to a frame. To provide for a symmetrically balanced and mechanically efiicient and quiet operation, a second set'of sprocket wheels 20A and 21A and a chain 22A therebetween, is supported on the other side of carriage 23, the follower pin 24 being connected also to chain 22A.

As best seen in FIG. 5, the larger sprocket wheels 29 and 20A are actually double sprockets, the inner wheel being coupled to the chains 22 and 22A, the outer wheel being coupled by chains 35 and 35A to drive sprocket wheels 34 and 34A. A motor 36 is operatively coupled by a shaft 37 to both drive wheels 34 and 34A to simultaneously drive both systems of sprocket chains. The arm (12 or 13) is mechanically linked to the top shoe 23 of the carriage, hence as the shoe slides back and forth on the rails, the holder is reciprocated accordingly.

Referring now to FIG. 6, one full cycle of operation of the reciprocating mechanism is illustrated diagrammatically. The orbital path taken by the follower pin is shown by path 0, which is the configuration of chain 22 on the two sprocket wheels. The linear horizontal path R taken by the carriage which is linked to the pin, represents the total distance between the extremes of the orbital path. The left-end portion T of the linear path R represents the distance travelled by the carriage while the follower pin passes over the small sprocket wheel, whereas the right-end portion C represents the distance travelled by the carriage while the follower pin passes over the larger sprocket wheel.

The axis X running longitudinally through the center of the orbit, marks the division between the forward stroke of the arm and the return stroke thereof, in that above the axis the carriage moves in the forward direc tion and below the axis the carriage moves in the reverse direction. The distance between the tend portions T and C of the linear path R represents the acceleration period of the arms, this distance S when the pin moves toward the end portion T being the forward stroke, and the same distance S in the reverse direction of the pin toward C being the return stroke.

During the end portions T and C the carriage 23, as the pins travel over the wheels, first moves in one direction and then in the other. The back-and-forth travel of the carriage movement during these periods represents the transfer and changover intervals of the arms, for while the cariage 23 never actually comes to rest during these intervals .but actually slows down and then accelerates, these periods serve effectively as the intervals during which the yarn is transferred, or other actions take place in the loom. The length of these intervals is determined by the diameter of the wheels, hence the interval is briefer with the smaller sprocket wheel. It will be appreciated, therefore, that the length of these intervals can be adjusted by proper selection of the sprocket-wheel diameters.

Thus in operation, the mechanism in accordance with the invention acts in the course of each cycle to advance the arm associated therewith to the midpoint of the fabric web, where the yarn from one arm is transferred to the other, both arms then returning to their retracted positions, at which point the Weft is fully laid-in. The arms remain at this position until the loom is ready for the next fill-in of weft yarn. The inherent mechanical efiiciency of the reciprocating mechanism is such that it becomes possible to carry out these operations at exceptionally high speed.

While there has been shown a preferred embodiment of the invention, it will be obvious that many changes may be made therein, without departing from the essential features thereof, as defined in the annexed claim.

What I claim is:

In a weaving loom, apparatus to introduce weft yarn into a shed formed by warp yarns and comprising a first arm for pulling weft yarn into said shed to a midpoint therein and a second arm to which said weft yarn is transferred at said midpoint for conveyance across the remainmg half of said shed to lay in said weft yarn, and mechanisms for reciprocating said first and second arms, each mechanism including first and second sprocket wheels mounted for rotation at positions spaced from each other and an endless chain intercoupling said wheels, a carriage operatively coupled to said arm and slidable on a horizontal trackway, said carriage having a vertically extending slot therein, and a follower pin attached to said chain and extending into said slot to cause said carriage to reciprocate as said pin travels the orbital path formed by said chain, said mechanism being arranged to operate concurrently to cause said arms alternately to move to- Ward and away from each other with respect to said midpoint, said wheels being of difierent diameter to cause the transfer period during which said arms are at said midpoint to be shorter than the changeover period during which said arms are retracted, and means actuated during the changeover period to sever the end of the laid-in weft yarn thereby to complete a weaving cycle, said loom further including a second set of first and second sprocket wheels and an endless chain intercoupling said wheels, said follower pin being also attached to the endless chain of said second set, said second set being disposed in parallel relationship to the first set of sprocket wheels, said horizontal trackway being disposed between said parallel sets whereby said carriage runs therebetween.

References Cited by the Examiner UNITED STATES PATENTS MERVIN STEIN, Primary Examiner.

DONALD W. PARKER, Examiner.

H. S. JAUDON, Assistant Examiner.

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