US2305420A

US2305420A - Hydraulic let-off

Info

Publication number: US2305420A
Application number: US414729A
Authority: US
Inventors: Jr Archibald J Herard
Original assignee: Crompton and Knowles Corp
Current assignee: Crompton and Knowles Corp
Priority date: 1941-10-13
Filing date: 1941-10-13
Publication date: 1942-12-15
Anticipated expiration: 1959-12-15

Description

De@ l5, 1942- A. J. HERARD, JR 2,305,420

HYDRAULIC LET-OFF Filed oct. 13, 1941 2 sheets-sheet 1 .gli

lNvcN-ron ARCHIBALD CI'. HER/nomi ATTORNEY Dec. 15, 1942.

A. J. HERARD, JR

HYDRAULIC LET-OFF Filed Oct. 15, 1941 2 Sheets-Sheet 2 ATTORNEY Patented Dec. 15, 1,942

Archibald J. Hei-ard, Jr.,

signor to Crompton & Knowles Loom.

Worcester, Mass., as-

Works.

Worcester, Mass., a corporation of Massachusetts Application october 13, 1941seria1No. 414,729?

' V10` Claims. (Cl.

This invention relates to let-olf mechanisms for. looms and it is thegeneralobject of the invention to provide a let-off controlled hydraulically by tension of the warp threads.

In certain types of let-off mechanisms itis customary to employ a whip roll which is moved forwardly by the tension ofv the warp during the weaving operation and while the warp beam is held stationary. When the whip. roll reaches a given forward position mechanism is-operated to release the warp -beam so that-it can be turned by theV warp to reduce tension and permit the whip roll to move rearwardly under the action of a weight or spring; When the whip roll reaches a critical rearward position the warp beam is again locked, and the alternate locking and unlocking of the beam by back and forth motion of the whip roll goes on throughout the weaving operation to supply the warp under proper tension as needed.v

It is an important objectof my present invention to provide a hydraulic system for controlling the warp beamtogether with means for acting on the system by mechanism dependent for'its operation upon a part, such asa whip roll, the position of which is changed by the warp. My invention contemplates` the use of brake shoes operated by a hydraulic unit connected, to ahydraulic cylinder the plunger of which .iscontrolled by the part to holdand release the beam 1 alternately during loom operation. Thesystem normally tends to cause the brake shoes to hold the warp beam stationary, and as thel whip.- roll moves forwardly the pressure within the system is gradually reduced until the brake shoes slacken` enough` to permit the Warp beam to turn. During the consequentslackening of the warp ,threadsthe whip roll moves rearwardly under action ofA the weight and acts .on' the cylinder plunger to return the shoes `to locking position. In the description to follow I haveillustrated a single system appliedto but one end ofthe loom, butl". am not limited, to such an application, as itis obvoius that the mechanism canvbe duplicated at the opposite end.

With these and other objects in view which will appear as the description proceeds, my invention resides in the combination and` arrangement of partsl hereinafter described and set forth.

In the accompanying drawings, wherein a convenient embodiment of my inventionis set forth, Y Fig. 1 is a rear elevation of-one end of a loom having my invention applied thereto,

Fig. 2 is a plan viewv taken in the direction of yarrow-1,21ig. 1 and;` showing the-,hydraulic sys'f tem under control of both ends of the whip roll, l

@ liig.` 9 is a vertical section through the brake operating hydraulic unit shown in elevation in Fig. 6.

i Referring particularly, to Figs. 1, 2 and 3,k I have shown a loomframe I', warp beam Il andv whip roll I2; of the usual construction. A bracket I3 securedto the loom frame extends rearwardly and: has pivoted thereto asn at I4 an upwardly extending yarm I5 on which the adjacent end -of thewhip roll is journaled as at I6. The warp W fromfthe warp beam is led upwardly 4and over thewhp roll and then forwardly to the point of;weaving.

A lever swinging in a vertical plane is pivoted as at 2| on the bracket I3 and has-a horizontal arm to support a weight rod 22` the lower end of which carries weights 23. As vshownparticnlarly in Fig.12 acontrollever 25 swinging in afhorizontal lplane is pivoted, as at A26 'to the bracket and has a lateral arm 21 to engage the front edge ofthe adjacent arm I5. Lever 25 also has a forwardly extending arm ZBYpivoted as atf'29 to a link 30 which in turn is pivoted to a second linkv 3l the right end of which is shown inv Fig. 1 as pivoted at 32 to a part of lever 2i) above the pivot 2I. A rod 33 connected to link 30 in `the' present instance is shown in Fig. 2 as extending across the loom to be connected to a second control: lever .similar to lever 25 to engage an, arm 36 similarv tovarm I5 onwhich y the leftend ofthewhip roll is journaled.`

YIn the mechanism thus far described, andassuming for the momentthat the warp kbeam is stationary, the whip roll I2 will moveforwardly to swing the arms I5 and 36 toward-thefront of the loom and effect alefthand angular motion of

levers

25 and 35 asviewedin Fig. 2. The attendant motion of arm-'28 to the leftlifts lever 2U against the action of the weights 23 which serve to tension the warp threads W. When the warpl beam is free to turn and thus reduce the tension in the warp threads theweights 23 fall and act through lever 20 and links 30 andl 3l to turn lever 25 in a right hand. direction vas viewed inFig, 2 to movethe arm I5 andfwhip 2,184,059 to which reference may be had for a.

further understanding of the structures already set forth.

The warp beam which I employ has secured thereto a shell to have frictional contact with. brake shoes mounted on a xed support which also supports the hydraulic brake shoe controlling unit as shown more particularly in Figs. 6

and 9. Secured to and extending rearwardly from the loom frame is a bracket 40 provided with a bearing 4| through which extends the right lend of the warp beam gudgeon or shaft 42`as seen in Fig. 7. A disk 43 bolted as atv 44 to bracket 40 supports studs 45 connected by a link 46, as indicated in Figs. 6 and '7. As shown in Fig.V 6 theV right and left studs 45 which pass through link 46'have pivoted thereon

brake shoes

41 and 48, respectively, which extend upwardly to a hydraulic brake `operating unit 49. The latter is held as at 58 to the disk 43, see Figs. 6 and 7, and is connected to a hydraulic tube 5|. 'Ihe brake shoes are therefore supported on fixed structure as is also the unit 49 and these parts are held against rotation around shaft 42v as will be apparent in Figs. 3 and 7.

The barrel of the warp beam is fastened to shaft 42 and has secured thereto a head 56 to lwhich is secured a drum 51.v A hub 58keyed to shaft 42 lies to the right of web 59 of the drum, and the hub, web and head are bolted together as at 60 to turn with the warp beam. Rods 6| located in grooves 62 extending longitudinally along the periphery of the barrel 55 are secured to the head 58, and act with shaft 42 to cause the drum to rotate with the barrel 55. The drum is formed with an internal cylindrical surface 63 positioned for engagement with `the external surfaces of the

' shoes

41 and 48. `rI he drum rotates with the barrel to feed n.warp and can either slide along the brake shoes if the latter are spaced from surface 63 as shown in Fig. 6, orbe' held by the shoes if they are forced apart and against surface 63 by the "unit 49. In -the latter instance the beam Awill be locked or -held in stationary position because of the support afforded the brake shoes by the bracket 40.

The unit 49 which issecured to the disk 43 and shown in Fig. A9 comprises a cylinder 65 having an Vinlet port-B6 intermediate the ends thereof on opposite sides of which are located front and back pistons 81 and 68, respectively. Rubber cupsY 69 Contact the inter-nal bores of the cylinder and each piston is provided with a pressure plug 10 for engagement with the

corresponding shoes

41 and 48; The ends of the cylinder may be closed'byrubber boots 1|, and a light compression spring 12 engages the cups 69 to hold them against their respective pistons. The fluid withinthe cylinder is confined between the cups and when subjected to increased pressure tends to move the pistons apart to force the brakeshoes against the cylindrical surface 63 of the drum 51. When pressure wlthin the cylinder 65 falls the pressure exerted by the pistons slackens and in order to insure release of the shoes from the braking surface 63 I employ a tension spring 13 between the

shoes

41 and 48 tending to draw the latter away from surface 83, as shown in Fig. 6.

The pressure of fluid in the member 49 is controlled through tube 5| which leads to a cylinder mounted in the present instance in fixed position and having a plunger the position of which can be changed to vary the fluid pressure within the system. As shown in Figs. 3 and 8 the bracket I3 has secured thereto a small stand 15 on the upper end 18 of which is mounted the pressure unit 11. The latter has a uid reservoir 18 on the upper part thereof communicating by means of aport 19 with a cylinder bore 80. A piston 82 slides in the bore 80 and is movable along the latter by a piston rod 83 the left end of which as seen in Fig. 2 is located for engagement with the arm 28. A by-pass port 85 leads from the reservoir to the bore 88 and a rubber cup 86 is normally located between the intake and by-pass ports, lbeing heldagainstthe piston 82 by a ,compression spring 81. A 'stop 88 limits motion of the piston to the left as viewed in Fig. 8 and serves to locate the cup,86 with respect to the ports.

The right end of spring 81 bears against a disklike structure 98 limited as to right hand motion by the end of the bore and having mounted therein a valve 9| which when open by fluid pressure incident to motion of the piston .82 to the right, Fig. 8, leads to the tting 92 the bore of which communicates with the hydraulic'tube 5|.

The relationship ofthe unit 49, tube 5| 'and cylinder 11 is such that whenv the rod 33 moves 'to the right as viewed in Figs. v2 .and A8 fluid within that part of the bore lying to the right of the by-pass port will be placedunder pressure land this pressure will be communicated through the tube 5| to the pistons 61 and 8.8. When the force acting on rod 33 is released or reduced, the spring 81 moves the piston to the left to effect a reduction of uid pressure withinV the system .and spring 13 draws the pistons 81 and 68 toward each other.

In operation, the weight 23will actas already described Vto hold the arm-28 in a right hand position, Fig. 2, when the whip roll is in its rearmost position, thus causing arm 28 to exert a force on piston rod 83 to the right as viewed in Figs. 2 and 8 to produce a relatively high level of fluid pressure within the system and cause the

brake shoes

61 and 88 to move against the drum 51 and hold the beam stationary. As warp is consumed the whip roll lwill move forwardly, thereby moving the arm 28 to the left or in-a direction away from the piston rod 83, whereupon the spring .81 will act to reduce the fluid pressure within the system until a, level is reached which permits the beam to.turn with respect to the brake shoes.l The tension .spring 13 assists ina vquick releaseof the brake shoes but is notV essential. When Vthe beam is vreleasedthe tension in the warp rotates the beam to feed warp forwardly with a resultant drop in warp tension which permits the weight 23 to move the whip roll rearwardly until arm y28 again moves piston rod 83 to the right to reestablishfbeam holdingpressures within the hydraulic system. l

'Ihe back and Vforth reciprocation of the whip roll goes on throughout the Weaving operation, the whip roll moving forwardly to a given point in its Acycle at which fluid pressure dropsfsuflicientlyrto release thebeam, whereupon the whip roll is returned by the weight to a secondtgiven point in its rearward travel at which holding pressures are again established. The drum surface 63 slides smoothly over the

shoes

41 and 48 to avoid abrupt 'movements of the warp beam and in this way' an even feeding action of the beam is attained.

From the foregoing it will be seen that I have provided a simpleand efficient means for regulating the locking and releasing of the Warp beam by means of a hydraulic system the fluid pressure of which rises and falls constantly during loom operation to lock and release the warp beam alternately. It will further be seen that the piston rod 83 is acted upon by means, such as the whip roll and arm 28, responsive to variations in tension in the warp and that increasing tension in the Warp operatesV through the hydraulic system to unlock thebeam. It will also be seen that the weight 23 serves not only to move the whip roll rearwardly when the warp is slackened but also supplies theforce needed to establish beam holding pressures within the hydraulic system.

The brake unit Q9, tube and pressure unit 11 as shown in Figs. 8 and 9 of themselves form no part of my prsent invention and may be of any approved form.` For a further understanding of these parts reference may be had to printed matter relating to hydraulic brake systems, such for instance as subject #2062 and 2140 shown in the catalogue of November 13, 1938,y of the Ford Motor Company. y

Having thus described my invention it will be seen that changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the invention and I do not wish'to be limited to the details herein disclosed. but what I claim is:

1. In a warp let-off mechanism vfor a loom having a rotatablevwarp beam, brake means for the beam movable.' either to holding position to prevent rotation of the beam or to releasing position to permit rotation of the beam, a hydraulic system connected to the brake means, mechanism acting normally on the systemito cause the latter to move the brake means to beam holding position, and other means to transmit an opposing force to the mechanism derived from the warp asthe tension of the latter increases during the weaving operation while the beam is prevented from rotating and cause the mechanism to effect a reduction of uid pressure within' the system to a level insuihcient to cause the brake means to hold the beam from rotation.

2. In a warp let-off mechanism for a loom having a rotatable warp beam, brake means for the beam, a hydraulic system connected to the brake means to control the amount of braking force exerted by said brake means on the warp beam, controller means for the hydraulic system, means operated by a force derived from the warp as the tension in the latter increases during the weaving operation when the warp beam is prevented from the rotating to cause -the controller means to effect a reduction of uid pressure within the hydraulic system to a level which permits the warp beam to move relatively to the brake means, and other means operative due to slackening of the warp tension incident to rotation of the warp beam to cause the controller means to establish fluid pressure within the system sufficiently high to cause the brake means to prevent rotation of the warp beam.

3. In a warp let-off mechanism for a loom having a rotatable warp beam, means moved from holding to releasing position by a force derived from the warp as the tension thereof increases during weaving, providec'i rotation'of the beam is prevented, brake mechanismv to'control rotation of the beam, a hydraulic system controlling the brake mechanism and vunder control of said means, return mechanism for the means to move the latter from releasing to holding position When tension in the warp is reduced, the means when in holding position maintaining suicient'pressure within said system to cause th'e brake mechanism to prevent rotation of said beam, said means when moving to releasing position reducing? the pressure within the system to a level insufficient to cause the brake mechanism to prevent rotation of the beam, whereupon the warp due to the tensionv thereof causes rotation of the beam to reduce the warp tension and the return mechanism moves the means to holding position to reestablish suiiicient pressure in the system to prevent further rotation of the beam.

4. In a warp let-off mechanism for a loom having a rotatable warp beam, brake means for the beam movable either to beam holding or releasing position, a hydraulic system connected to and controlling the brake means, a whip roll movable forwardly to a given position during the weaving operationv by a force derived from the warp when the warp beam is held against rotation, means tending normally to move the whip roll rearwardly toca second given position, and mechanism `to vary thefluid pressure within the system, said mechanism being caused by a force derived from the whiproll when the latter moves forwardly to said first given position to produce a pressure within the system insufficient to cause the brake means to hold the warp beam, and said mechanism effective when the whip roll moves rearwardly to said second given position to produce sufficient pressure within the system to cause the brake means to hold the warp beam against rotation.

5. In a warp let-off mechanism for a loom having a rotatable warp beam and a whip roll movable forwardly by the Warp during'the weaving operation when the beam is prevented from rotating, the loom having return means to move the whip roll rearwardly due to lessening of the warp tension when the beam rotates to feed warp, brake means for the beam movable toholding position tov prevent rotation of the beam, release means to move the brake means to releasing positionto permit rotation of the beam by the Warp, a member moved by the whip roll from holding to releasing position when the whip roll moves forwardly, said return means to move the member from releasing to holding position when the whip roll moves rearwardly, and ahydraulic system .connectedv to thev bra-ke means and` controlled by the member to have the pres-- sure therein increased to move the brake means to holding position when the'member moves to holding position, and have the pressure therein reduced when the memberkmoves to releasing position, whereupon the release means moves the brake means to releasing position.

6. In a warp let-off mechanism for a loom hav-- ing a rotatable warp beam and a whip roll movable forwardly by the warp during the weaving operation when the beam is prevented from rotating, the loom having return means to move the Whip roll rearwardly due to lessening of the warp tension when the beam rotates to feed warp, brake means for the beam movable to holding position to prevent rotation of the beam, release means to move the brake means to releasing position to permit rotation of the beam by the warp, and a hydraulic system connected to the brake means and controlled by the whip roll and said return means, the whip roll when moving forwardly operative to decrease the pressure within said system to permit the release means to move the brake means to releasing position, and said return means operative when the whip roll moves rearwardly to increase the pressure in said system to overpower said release means and move the brake means to holding position.

7. In a warp let-off mechanism for a loom having 'a rotatable warp beam, a whip roll for the warp movable backwardly and forwardly, means including a weighted lever tending normally to move the whip roll rearwardly, the warp due to increase in tension therein during the Weaving operation moving the whip roll forwardly against the action of the weighted lever when the warp beam is held against rotation, brake means for the warp beam movable to holding and releasing positions with respect to the beam, a hydraulically operated unit for the brake means, a hydraulic cylinder having a plunger in position for operation by said weighted lever, and tubular means connecting the unit and cylinder, said unit, cylinder and tubular means constituting a hydraulic system, the lever when moving in a direction to move'the whip roll rearwardly operating the plunger to increase the fluid pressure within the system and cause the unit to move the brake means to holding position with respect to the beam, and said Weighted lever being moved in a direction away from the plunger by forward motion of the whip roll reducing the fluid pressure within the system, whereupon the beam rotates with respect to the brake means due to tension in the warp and said weighted lever moves the weighted lever rearwardly and causes the plunger to create suficient fluid pressure within the system to move the brake means toA beam holding position. A

8. In a warp let-off mechanism for a loorn hav- Whip roll forwardly during the weaving operation when the warp beam is prevented from rotating, a lever having two arms one of which is operatively related to the whip roll and movable therewith, a Weight connected to the second arm ofthe lever, said weight tending normally to move the first arm in a direction to cause rearward motion of the'whip roll, brake means for the warp beam movable to holding and releasing positions relatively to the beam, vand a hydraulic system between said lever andthe brake means including a unit to control the brake means, said system including a cylinder having a plunger to be moved by the weight acting on the lever in a direction to lincrease the'uidpressure withinthe system-when the first named arm moves in the direction corresponding to rearward motionl of the whip roll to cause the-unit to move the brake means to beam holding position, movement of the first named arm in a direction corresponding tov forward motion of `the whip roll moving the lever in a direction away from the plunger, whereuponl fluid pressure within the system 4is decreased to vpermit turning of the beam relatively to the brake means, the weight being effective through the lever to movethe Whip roll rearwardlyand reestablish sufcient fluid pressure within the system tocause the brake means to prevent 'rotationof the warp beam. n.

9. In a Warp let-off` mechanism for amloom having a rotatable warp beam, brake means for the beam, a'hydraulic system connected vto the brake meansto control the amount of braking force exerted therebyon the warpl beam, a whip roll moved forwardly by the warp during the weavingv operation when the warp beam is prevented from turning,weighted means tendingnormally to move the whip roll rearwardly, V'a controller yfor the system to determine the fluid pressure with-r in said system, controller actuator means by' which the whip roll when moving forwardly causes the controller to reduce the lluid pressure within the system to a point which will permit the warp beam to turn with respect to the brake means, and the weighted means effective' during rearward motion of the whipwroll. to move the. actuator means to cause the 'controller to -in-I crease the'fluid pressure of the system to a point whichv will cause the brake means to preventv rotation of the Warp beam.

l0. In a warp let-off mechanism for a loom having a rotatable warp beam, brake means'for the beam, a hydraulic system connected to the brake means to control the amount of braking force exerted by said brake meansv on the Warp. beam, a controller for the hydraulic system movable in one direction toA decrease and in the 0p'- posite direction'to increase the fluid pressure within said system, controller actuator means vto cause the whip roll when A,moving forwardly. to

move said controller in said 'onedirec'tiorr means to move the Whip roll. rearwardly a'n'dfmoveA the actuator means to cause movement of thecontrolle'r in said opposite direction, the increase in fluid pressure within the system being sufficient crease. in pressure within'the' fluid system reach.- ing a level insufficient to enable th'e brake means to prevent beam rotation when'the whip roll reaches a `given position in its forward motion.