US2946352A - Loom let-off mechanism - Google Patents

Description

July 26, 1960 1. B. M KEOWN 2,94,352

LOOM LET-OFF MECHANISM Filed April 13, 1959 3 Sheets-Sheet 1 3 IRMA B. MEKEowN ATTORNEYS INVENTOR.

July 26, 1960 I. B. M KEOWN 2, 4 5

LOOM LET-OFF MECHANISM Filed April 13, 1959 3 Sheets-Sheet 2 him 5. MEKEOWN BY w, mw+ W ATTORNEYS Juiy 1. s. MCKEOWN 2,946,352

LOOM LET-OFF MECHANISM Filed April 15, 1959 3 Sheets-Sheet 3 INVENTOR: IRMA B M KEowN 2; B finazmmw-m k ATTORNEYS Patented July 26, 1960 1.00M LET-OFF MECHANISM Irma B. McKeown, PA). Box 5091, Charlotte 6, N.C.

Filed Apr. 13, 1959, Ser. No. 806,125

4 Claims. ((11. 139-110) This invention relates generally to improvements in loom let-off mechanisms and more particularly to a letoff mechanism adapted to rotate the Warp beam and let 01f the yarn at a rate which corresponds to the rate at which the woven cloth is taken up.

In the weaving of cloth, it is desirable to feed the warp yarns at the same rate of speed that the cloth is taken up while maintaining the warp yarns under equal tension at all times. There have been many let-off devices employed, all of which were striving, by one means or another, to maintain the warp yarns under equal tension while feeding the yarns at a rate corresponding to the rateof production of the cloth.

Generally, there are two warp let-off systems presently employed. In one system, the warp yarns are let off or unwound from the warp beam in accordance with the amount of friction applied to a brake drum associated with the warp beam. In the other system, the warp beam is rotated in a step-by-step intermittent manner by a mechanism which is controlled by the tension of the warp yarns. In the latter system, the warp beam is intermittently rotated in equal steps by means of a ratchet and pawl arrangement which is drivingly connected to a large gear on one end of the warp beam. In this system, the step-by-step rotation of the warp beam is controlled by movement of a whip roll over which the warp yarns pass and the whip roll is operatively connected with the pawl and ratchet. Thus, each step of rotation of the warp beam is the same length and corresponds to the spacing between the teeth of the ratchet. .With this system, each time the pawl and ratchet mechanism is operated the warp beam lets off a fixed amount of yarn when the tension of the yarns reaches a predetermined amount. This type of let-off does not feed the warp yarn in amounts which correspond to the demands of the weaving operation since the warp beam is rotated equal amounts with each step.

With the foregoing in mind, it is the primary object of this invention to provide an improved let-off mechanism which is responsive to the tension of the warp so that the Warp beam is rotated in intermittent steps and the yarn is unwound or let off varying amounts which are commensurate with the amount of tension on the warp yarn to thereby maintain the warp yarns under a more uni form tension than has heretofore been possible.

It is another object of this invention to provide an improved let-ofi mechanism for intermittently rotating the warp beam of a loom by means of an overriding or oneway clutch mechanism which is interposed between the warp beam driving pinion and the operating components of the loom whereby the warp beam will be rotated in a step-by-step manner to let off the warp yarns varying amounts which correspond to the tension of the warp yarns,

It is another object of this invention to provide an improved let-ofi mechanism for intermittently rotating the warp beam in a step-by-step manner in varying amounts and which mechanism is provided with means for readily 2 engaging and disengaging the let-off mechanism from the warp beam.

It is a more specific object of this invention to provide an improved warp tension controlled let-off mechanism which is of simplified construction, adapted to be readily installed on existing looms and requires very little adjustment prior to and during its operation.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds, when taken in connection with the accompanying drawings, in which Figure 1 is a fragmentary elevation of the lower righthand rear portion of a loom with portions broken away for purposes of clarity and illustrating the improved letoif mechanism of the'present invention associated therewith;

Figure 2 is an enlarged fragmentary vertical sectional view taken substantially along the line 2--2 in Figure 1, with parts broken away, and illustrating the type of oneway clutch used in connection with the improved let-ofi mechanism of the'present invention;

' Figure 3 is a fragmentary end elevation, with parts in I section and parts broken away, illustrating the invention associated with a fragmentary portion of the rear portion of one end frame and being taken substantially along the line 3-3 in Figure 1;

Figure 4 is a fragmentary plan view looking downwardly on Figure 1 and in the direction of the line 4-4;

Figure 5 is a horizontal sectional view taken substantially'along the line 5--5 in Figure 1.

Referring to the drawings, the present invention is shown associated with a conventional loom having a side frame 10 which supports one end of a warp beamil having a plurality of warp yarns W wound thereon. The warp beam 11 is supported on a shaft 13 which is in turn rotatably supported on a bracket 14 suitably secured to the rear portion of the loom frame iii. The warp beam 1-1 is provided with a relatively large gear 15 which is suitably secured to one end of the warp beam and is utilized to drive the warp beam, in a manner to be later described. The loom frame 10 also supports a main cam shaft 20 which is a conventional part of the drive mechanism of the loom and is driven in timed relation to operation of the loom so that the shaft 20 makes one revolution for each two picks of the loom.

The loom is also provided with the usual instrumentalities for forming cloth, not shown, whereby with each pick of the loom the warp yarns are separated by the heddles to form a shed. A filling yarn is inserted in the open shed and as the warpyarns are again joined and the lay is moved forwardly to beat-up position to move the filling yarn into position to form another pick of the woven cloth. The loom is'also provided with a suitable cloth take-up roll, not shown, which maintains the cloth and warp yarns under tension and'takes up the cloth as it is formed. Movement of the take-up roll is controlled in timed relation to operation of the loom and'the take-up roll is rotated to take up the cloth in a step-by-step manner and in equal increments.

The loom is also provided with a whip roll 25 (Figures 1 and 4) having a support shaft 26 extending therefrom and the distal end of which is mounted for rotation in a bearing block 27. The bearing block 27 is removably supported in the rear end of a bracket 30, the front end of which is fixed on one end of a pivot shaft 31. The pivot shaft 31 is mounted for oscillation in the upper end of a bearing support 32, the lower end of which is fixed on the rear end of a support bracket 33 suitably secured at its front end to the loom frame 10. The end ofthe pivot shaft 31, opposite the bearing support 30, has one end of a lever 35 fixed thereto and the opposite end of the lever 35 has the upper end of a tension spring 36 suitably secured thereto. The lower end of the tension spring 36 is connected to an eye bolt 37 which is mounted for vertical adjustment in the horizontal leg of an angle bracket 40. The angle bracket 40 is suitably secured to a pivot bracket 41 which is in turn fixed on the side frame (Figure 3).

The warp yarns W are unwound from the warp beam 11 and pass upwardlyand over the whip roll 25, then forwardly through the usual heddles and loom reed, not shown, to join the cloth being woven. The amount of tension in the warp yarns W determines the vertical position of the whip roll 25 since it is mounted in a floating condition and may oscillate with fluctuations in the warp tension. The amount of upward pressure of the whip roll 25 against the sheet of warp yarns W depends upon the amount of tension in the spring 36 (Figure 3) and the amount of tension in the spring 36 may be varied by adjusting the vertical position of the eye bolt 37.

Thus, when the tension in the warp yarns W is increased, by reason of the cloth being taken up, the whip roll 25 will be moved downwardly slightly against the tension in the spring36. On the other hand, when tension in the warp yarns W is lessened, by reason of the yarns being unwound from the warp beam, in a manner to be later described, the tension spring 36 will cause the whip roll 25 to be raised. It is to be understood that where p the terms greater and lesser tension are used, they do not refer to substantial degrees of variation in the normal tension of the warp yarns but to small degrees of variation in tension which normally occur in the warp yarns when the cloth is taken up and when the yarn is let oif of the warp beam.

The improved let-off mechanism of the present invention operates in response to small variations of tension in the warp yarns which are indicated by variations in the position of the floating whip roll 25. It is with the type of loom heretofore described that the present let-off mechanism is preferably associated, but it is to be understood that it may be applied to other types of looms, if desired. One important feature of the present let-oft mechanism resides in the fact that the amount of yarn let off by rotation of the warp beam is always in exact proportion to the amount of tension applied to the sheet of warp yarns W prior to action of the let-01f mechanism. Thus, when the tension in the warp yarns increases greatly the improved warp let-off mechanism of this invention supplies a greater amount of yarn than it does when the warp tension increases only slightly above the amount desired.

In order to transmit any variations in the position of the whip roll 25 to the let-off mechanism, the whip roll 25 is operatively connected to the let-oif mechanism by a composite link broadly indicated at 45. The link 45 comprises a sleeve 46, the upper end of which is oscillatably connected, as at 47, to the bracket in which one end of the whip roll 25 is-rotatably supported. The composite link 45 also includes a control rod 50 mounted for sliding movement in the sleeve 46 and the upper end of the control rod 50 is threaded to receive a pair of lock nuts 51 which seat against the upper end of the sleeve 46 and limit downward movement of the control rod 50. The lower end of the control rod 50 extends downwardly beyond the lower end of the sleeve 46 and is oscillatably connected to the medial portion of an actuating lever '55. A compression spring 60 surrounds the control rod 50 and its upper end bears against a washer which is seated against the lower end of the sleeve 46 while its lower end bears against a washer which is seated against a pair of lock nuts 61 threadably mounted for longitudinal adjustment along the control rod 50. The spring 60 normally holds the control rod 50 in its lowermost position relative to the sleeve 46 and the lock nuts 51 may be rotated to increase or decrease the effective length of the composite link 45.

. The forward end of the actuating lever -55 is provided with a cam roller 64 which is in vertical alinenient with an actuating cam 65 suitably secured to the main cam shaft 20. The rear end of the actuating lever 55 is fixed to the upper horizontal portion of a clutch housing in which the outer element 71 of an overriding or one-way clutch broadly indicated at 72 is mounted. In this instance, the outer element 71 is formed of a hardened steel sleeve which is clampingly held in a fixed position in the housing 70 by a screw 73 (Figure 2). The oneway clutch 72 also includes an inner element 74 which is provided with a plurality of cam openings 75, each of which is provided with a roller 76. It will be noted in Figure 2 that the bottoms of the openings 75 are cut at an angle and the rollers 76 are urged into engagement with the outer element 71 and the bottoms of the openings 75 by compression springs 77.

When the free or operating end of the actuating lever 55 (Figure 3) is raised, the clutch housing 70 and outer element 71 are rotated in a counterclockwise direction so that the rollers 76 are wedged between the outer and inner elements 71 and 74 and transmit the rotational motion to a let-off shaft 80 to which the inner element 74 is keyed. On the other hand, when the free end of the actuating lever 55 is lowered, the clutch housing 70 and outer element are rotated in a clockwise direction so that the rollers 76 are not wedged between the outer and inner elements 71 and 74. Thus, when counterclockwise rotation is irnparted to the clutch housing 70, the shaft 80 will be rotated in a counterclockwise direction but when clockwise rotation is imparted to the clutch housing 70 the shaft 80 will not rotate.

Referring to Figure l, it will be noted that the medial portion of the shaft 80 is mounted for rotation in an eccentric sleeve 82 which is supported adjacent opposite ends in bearing members 83 and 84. The bearing member 83 is suitably secured to the side frame of the loom 10 (Figure 3) and the bearing member 84 is suitably supported on one upstanding leg of a substantially U-shaped support casting 85 (Figure l). The horizontal portion of the casting 85 is fixed to an outwardly extending portion of the side frame 10 while the other upstanding leg is suitably fixed to the side frame 10.

The eccentric sleeve 82 (Figures 1 and 5) has an enlarged boss or hub formed integral with the central portion thereof and the hub 90 has one end of a lever 91 fixed thereto or formed integrally therewith. The free end of the lever 91 has the lower end of a link 92 oscillatably connected thereto as at 93 (Figure 3) and the upper end of the link 92 is oscillatably connected, as at 94, to the medial portion of a hand lever 96. The lower end of the hand lever 96 is oscillatably mounted as at 97 on the rear end of the bracket 41, heretofore described. When the hand lever 96 is positioned as shown in Figure 3, it abuts against the horizontal leg of the angle bracket 40 to prevent rotation of the hand lever 96 in a clockwise direction.

The outermost end of the shaft 80 has a brake wheel 100 fixed thereto (Figures 1 and S), the outer periphery of which is engaged by a brake strap or band 101. One end of the band 101 is suitably secured to a support 102 fixed in the casting 85 and the other end supports a weight member 103. The wheel 100 and the brake band 101 thus present a braking action to frictionally resist rotation of the shaft 80 in either direction and the amount of frictional resistance depends upon the size of the weight member 103. The innermost end of the shaft 80 has a driving pinion 106 fixed thereto (Figures 1 and 5) which is normally positioned in driving engagement with the gear 15.

In operation, assuming that the warp yarns W are under the desired amount of tension, the actuating lever 55 will be supported by the whip roll 25 and the composite link 45 so that with rotation of the main cam shaft 20 the cam 65 will pass by the cam roller 64 on the forward end of the actuating lever 55 without raising the same. Thus, when the free end of the actuating lever 55 is held in a raised position, shaft 80, pinion 106 and the warp beam 11 will not be rotated. Of course, the tension in the warp yarns W will not remain constant because the cloth is continually being taken up to thereby increase the tension on the warp yarns W. When the cloth is taken up the tension on the warp yarns W will increase and lower the whip roll 25. With downward movement of the whip roll 25, the composite link '45 and the free end of the actuating lever 55 will also be lowered (Figure 3) in proportion to the amount of increase in tension in the warp yarns W.

When the forward end of the lever 55 is lowered, the clutch housing 70 will be rotated in a clockwise direction around the inner clutch element 74 without imparting any rotation to the shaft 80. Then, as the cam shaft 20 rotates the high portion of the cam 65 will engage and raise the cam roller 64 and the free end of the lever 55 to impart counterclockwise rotation to the clutch housing 70 (Figure 2). As counterclockwise rotation is imparted to the housing 70, the rollers 76 will cause this rotation to be imparted to the inner element 74. Thus, the distance the forward end of the actuating lever 55 is lowered will determine the amount of movement imparted to the shaft 80 through the clutch 72 when the cam 65 engages the roller 64 to raise the free end of the lever '55. As counterclockwise rotation is imparted to the shaft 80 (Figure 3), like rotation will be imparted to the pinion 106 to transmit a corresponding amount of clockwise rotation to the gear 15 and the warp beam 11 to let off a corresponding length of warp yarn W. As the warp yarns W are let off, by a step in rotation of the warp beam 11, the tension in the warp yarns W will be decreased thus allowing the tension spring 36 to raise the whip roll 25 slightly thereby raising the free end of the actuating lever 55 an amount which corresponds to the amount the tension in the Warp yarn W is decreased.

The compression spring 60, surrounding the lower end of the control rod 50, allows the free end of the actuating lever 55 to be raised by the cam 65 without causing a corresponding rise of the whip roll 25. When the free end of the lever 55 is raised, the compression spring 60 will be compressed and the control rod 50 will slide upwardly in the sleeve 46. The compression spring 60 also returns the control rod 50 to its lowermost position in the sleeve 46 following each engagement of the cam 65 with the cam roller 64 on the forward end of the lever 55. The lock nuts 51, threadably mounted on the upper end of the control rod 50, provide adjustment means for varying the effective length of the composite link 45 to thereby adjust the position of the cam roller 64 and the actuating lever 55 relative to the position of the whip roll 25. This adjustment enables the operator to adjust the amount of yarn let off with a given variation of tension in the warp yarns W.

At times, such as when a break-out occurs in the warp yarns, it is necessary to slacken the warp yarns and the present let-off mechanism may be easily released from driving engagement with the warp beam 11. In order to release the let-off mechanism, the operator revolves the handle 96 (Figure 3) in a counterclockwise direction ap proximately 180 degrees, thus moving the same out of engagement with the horizontal leg of the angle bracket 40 and lower the connecting link 92 along with the outer end of the lever 91. This movement will revolve the eccentric sleeve 82 and lower the shaft 80 whereby the pinion 106 will move out of engagement with the relatively large gear 15 carried by the warp beam 11. Rotation of the handle 96 will thus completely disengage the warp beam 11 from the let-off mechanism and the warp beam 11 may then be revolved as desired. In order to again engage the let-off mechanism with the gear 15 of the warp beam 11, it is merely necessary that an operator revolve the handle 96 in a clockwise direction so that it again abutsv against the horizontal leg of the angle bracket 40 and the shaft will be raised upwardly so that the pinion 106 again engages the gear 15. I

It is preferred that the let-off mechanism be operated from a cam on the main cam shaft, as illustrated, but it is to be understood that the actuating lever 55 may be operated from other conventional parts of the drive or other operating mechanisms of the loom which operate in timed relationship thereto. The let-off mechanism shown operates on alternate picks of the loom but could be operated on every pick by providing two high cam lobes on the cam 65.

The warp let-off mechanism of the present invention is operated in response to any variation in the tension of the warp yarns to feed or let-oif the warp yarns in va1i able amounts, according to the amount of variation in tension of the warp yarns. In other words, the greater the increase in tension of the warp yarns the greater the amount of yarn which is let off by the mechanism to thus immediately lessen the tension in the warp yarns. Any variation of the tension in the warp yarns is immediately detected and the improved let-off mechanism immediately feeds the correct amount of yarn to correct the tension in the warp so that the desired tension in the warp yarns may be maintained within a very close range.

In the drawings and specification there has been set forth a preferred embodiment of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

I claim:

1. Ina warp beam let-off for a loom having a frame, a Warp beam with warp yarns wound thereon, and a movable whip roll over which said warp yarns pass, said whip roll being movable in response to variations in the tension of said warp yarns; said let-oif comprising a gear carried by one end of said warp beam, a pinion engaging said gear, an eccentric sleeve oscillatably supported on said frame, a shaft rota-tably supported in said eccentric sleeve, said pinion being fixed on one end of said shaft, brake means adjacent the other end of said shaft to frictionally resist rotation of said shaft, a one-way clutch carried by said shaft, an actuating lever connected at one end to said clutch, actuator means operable in timed relation to operation of said loom, said actuator means being at times engageable with the other end of said actuating lever, link means operatively connecting said actuating lever with said movable whip roll whereby the position of said whip roll determines the position of the other end of said actuating lever in relation to said actuator means, and manually operable means for oscillating said eccentric sleeve to move said pinion into and out of driving engagement with said gear.

2. In a let-off for a loom having weaving instrumentalit-ies including a warp beam, warp yarns wound on said warp beam, a whip roll over which said warp yarns pass as they are fed to components of the weaving instrumentalities of said loom, said whip roll being resiliently supported and movable in response to variations of tension in said warp yarns; said let-off comprising a gear on one end of said warp beam, an eccentric sleeve oscillatably supported on said loom, a shaft rotatably supported in said eccentric sleeve, a pinion fixed on one end of said shaft and engageable with said gear, brake means supported on the other end of said shaft for friotionally resisting rotation of said shaft, a one-way clutch device carried by said shaft whereby movement of said clutch device in one direction will cause corresponding movement of said shaft and movement of said clutch device in the other direction will not effect movement of said shaft, an actuating lever connected at one end to said oneway clutch, cam means intermittently engageable with the other end of said actuating lever for imparting movement to said actuating lever in said one direction, a contrQllink operativelyconnecting said whip roll and actuating lever for controlling movement of said actua ling lever insaid other directionto thereby control the degree, of movement imparted to said lever in said one diIeQtion, and manuallyoperablemeans for oscillating said eccentric sleeve to thereby selectively move said inion into and out of driving engagement with said gear.

3. In a structure. according to claim 2 wherein said control link comprises a sleeve operatively connected at one end to said Whip roll, a rod slidably supported in said sleeve, adjustable stop; means at one end of said rod, said stop means being en gag sflble" with said one. endof said sleeve,sand resilient means, carried adjacent the other end; of said rod andengageable. with the other end, of said sleeve. for resiliently urging said step means into engagement with said one end of said sleeve, said other end of said rod being connected, intermediate the ends of said actuating lever.

4. In a structure according to. claim 2 wherein said manually operable means comprises a handle. osciliatably mounted at one end in said frame, a link connected at one end intermediate the ends of said handle, a lever connected at one end to said eccentric sleeve, the other end of said link being connected to'the other'end of said lever, and stop means on said loom engageable with said handle. a

References Cited'in the file of this patent UNITED STATES PATENTS Bergstrom June. 3; 19578

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