US2207104A - Letoff for multibeam looms - Google Patents

Description

y 9, 1940- o. v. PAYNE 2,297,104

LETOFF FOR MULTIBEAM LOOMS Filed 061;. so, 1939 3 Sheets-Sheet 1 iNVE NTOR OscAR V. PAYNE 2 3L amfw In 10 AT To RNEY y 9, 1940- o. v. PAYNE I LETOFF FOR MULTIBEAM LOOMS Filed Oct. 30, 1959 3 Sheets-Sheet 2 INVENTOR OscAR V PAYNE ATTORNEY y 9 1940. o. v. PAYNE 2 207,10

LETOFF FOR MULTIBEAM LOOMS Filed Oct. 30, 1939 3 Sheets-Sheet 3 {Ill lNVENTOR OSCAR \l. PAYN E A-r'roRN Patented July 9, 1940 A nd , 2,207,10 I wrote FOR MULTIBEAM .LooMs ilscar V. Payne, Leicester, Mass, assigns: to

firornpton & Knowles Loom worksyworcester, Mass a corporation of Massachusetts Application Gctober 39,

10 "Claims.

This invention relates to improvements in letoiis for wide looms and it is the general object of the invention to permit a singleletofi mechanism to be used with a plurality of warp beams 5 the warps of which are incorporated into'the same fabric. Y

In wide looms such as those used by the manufacturer of paper felts it has been customary heretofore to wind the warp threads on a single vbeam which extends across the width of the loom which in some instances may be five hundred inches or more in length. It is a difllcult matter to wind beams of this lengthand also to handle them when they are being put into a loom. The handling and winding of the warp for looms of this width would be facilitated if two or more shorter beams could be employed. With plural beams the warp threads derived from the independent beams would all be incorporated into the same woven fabric and any condition causing a greater tension on the warp of one beam than that existing on the warp of another beam would produce a faulty cloth which would not hold its shape because of uneven tensions in the warp threads in it.

It is an important object of my present invention to provide means by which plural warp beams can be regulated so that the tension of their warps will be the same. This result I accomplish as set forth hereinafter by the use of a single letcff mechanism attached by equalizing connections to the beams, the effect of the connections being to cause the stress exerted on the warp threads by the letoff mechanism-to be the same in each of the comparatively short beams.

The form of letoff which I employ cooperates with a movable whip roll which is moved toward the front of the loop as warp is consumed and it is then moved rearwardly by weights or the like which automatically come into action to produce rearward motion of the whip roll when the warp tension reaches a given amount. It is a further object of my present invention to provide each of the comparatively short warp beams with an individual whip roll which is connected by the aforesaid equalizing connections to the letoff mechanism so that a single weight forming part.

1939, Serial No. 301,863 Y that I am not necessarily limited to the type :of letoif shown in these prior disclosures. The lmounting'for the whip rolls of the different beams may also be 'similar tothat shown in mycopending application Serial No. 279,712 but I do *5 not wish necessarily to be limited to the use of the link suspension set forth inthe last named application. Referencemay be had however to these co-pending applications and the patent specified fora more detailed description of their structureiand operation than is deemed necessary for a description of my present invention. In the description-to follow I have set forth two forms ofthe invention the preferred form of which employs a cable and sheave hereinafter described. The equalizing of the forces acting on the whip roll can be effected however by means other than the cable and sheave andin the modifled form oftheinvention I illustrate an alternative method: which-employs a floating lever r20 mounted on :the weighted lever andattached by connectors such as rods to the mechanism which controls and also iscontrolled by the whip rolls. While I havevshcwn these twomeans for effecting --equa-lization of theiorces as mentioned I do M12 Wish necessarily to be limited to themin the practice of my invention. I v With these and other objects in view which will, appear as the description proceeds, y invention resides in the combination and arrangement of partshereinafter described and set forth.

In the accompanying drawings, wherein two forms ,ofmy invention are set forth,

Fig. .1 is a plan view of the rear end of a'loom having the'preferredform of my invention'applied thereto and showing the warp supplied by two aligned beams which supply the threads to be incorporated into the fabric being wovenon the loom,

Figs. 2, 3 and-4 are detailed views taken in thedirection of arrows 2, 3 and 4, respectively, of Fig. 1.

Fig. 5 is an end elevationlookingin the directionof arrow 5 ,.Fig.,l,

Fig. Sis a rear elevation of the structure shown Fig. '7 is a detailed end elevation of the'letofi escapement control for the warp beam at the right end of the loom looking in the direction' of arrow 1 Fig. 6,

Fig.8 isa detail plan view on enlarged scale in the direction of arrow 8, Fig. 5, V

,Fig. 9 .is'a detail elevation in the direction Qifl w; T 531 3 -55 Fig. 10 is a detail plan view in the direction of arrow 10, Fig. 3,

Fig. 11 is an enlarged vertical section on line H-ll, Fig. 5,

Fig. 12 is a diagrammatic perspective view showing the relation between the cable, its sheave, and the several levers connected thereto, and

Fig. 13 is a diagrammatic elevation taken from the rear of the loom and showing the modified form of my invention.

In the detailed description of my invention I will first set forth briefly a type of letofi' mechanism as illustrative of means for moving the whip roll in response to changes in warp tension as shown for Instance in my Patent No. 2,184,- 059 and also a mounting for the whip rolls similar to that shown in another of my co-pending applications Serial No. 279,712.

Referring to the drawings, particularly Figs. 1, 6 and 7 I have shown a loom frame I 0 at the rear of which in the present instance is mounted two separate horizontally aligned warp beams II and I2 located respectively at the right and left hand ends of the loom as viewed from the rear and having a fixed common center bearing U. These beams supply respectively warp threads W and W which lead upwardly over warp rolls l3 and M, respectively, and thence to the forward part of the loom for the production of warp sheds through which the shuttle not shown is picked. Movement of the warp beams in a direction to feed the warp threads W and W, and also the forward and backward motions of the whip rolls toward and from the front of the loom are regulated by a letofi mechanism designated generally at L, see more particularly Figs. 6 and 7. Parts of this mechanism are duplicated at both ends of the loom, the mechanism L being adjacent the beam l I while a similar mechanism L is adjacent the beam l2. Since these mechanisms L and L' are similar to each other I will give a detailed description of but one of them.

The gudgeon I5 of warp beam II has mounted thereon a gear I6 meshing with a pinion I'l fast with a larger gear 18, bothof these parts being secured to and rotating with a shaft 19 supported in a housing 20. Gear l8 meshes with a pinion 2| secured to a shaft 22 and rotating with a gear 23 also secured to shaft 22' and meshing with a pinion 24 secured to an escapement shaft 25 to which is also secured an escapement wheel 26. The latter cooperates with an escapement pawl 27 pivoted at 28 with respect to the housing 20 and having fingers 29 and 30 which move with respect to the escapement wheel in such a way that when the pawl rocks in one direction one of the fingers moves out of engagement with one of the escapement teeth 3| and the other finger enters a notch between two adjacent teeth on the escapement wheel. In this way oscillation of the pawl about its pivot permits rotary motion of the escapement wheel.

The pawl is restrained by a brake lever 32 pivoted as at 33 on the housing 20 and having pivoted at the left end thereof as viewed in Fig. 7 a brake shoe 34 for engagement with an armate brake rim 35 formed on the pawl. When the shoe is in engagement with the rim the pawl is locked against oscillation and the escapement wheel and the gearing connected thereto are held against rotation to hold the beam against rotation. When the shoe moves away from the rim 35, however, the tension of the warp thread tends to rotate the gear H5 in the direction of arrow (1,

Fig. 7, and urges the escapement wheel to rotate and effect oscillation of the pawl.

The mechanism for controlling the brake lever 32 includes a rod 36 passing through the right arm 31 of lever 32 and having a stop collar 38 fixed thereto under the arm 37. A compression spring 39 surrounds the rod 36 and extends upwardly from the lever to a sleeve 40 loosely sur-- rounding the rod and having its upper position determined by an adjusting nut N. The upper end of the rod is pivoted to a bell crank lever 4i pivoted with respect to the loom frame at 2 and having an upwardly extending arm 43 pivotally connected to a rod 44 extending to the left as viewed in Fig. 1 to a pressure lever 45 moving about a fixed pivot 46, see Fig. 1. A11 arm 47 of the lever 45 extends laterally and bears against a lug 48 to be further described and moving with Whip roll l3.

From the matter thus far described it will be apparent that forward motion of the whip roll I3 due to tightening of the warp passing over it will rock lever 45 in a counter-clockwise direction to pull rod 44 to the left and raise rod 36 the effect of which is to move the shoe 34 away from the rim 35 and allow the pawl to oscillate with resultant forward feeding of warp from beam ll. When the beam turns to feed warp forwardly pressure on the whip roll is slackened, and by means of weighted mechanism to be described hereinafter the lever 45 is acted upon to turn in a clockwise direction as viewed in Fig. l to exert a rearward force on lug t8 the effect of which is to move the whip roll l3 rearwardly. During this last named turning of lever 45 rod 36 will descend and ultimately effect engagement between the shoe 34 and the rim 35 to lock the pawl and arrest further rotation of the warp beam for the time being.

The matter thus far described relates to the letoff mechanism and is similar to the structure set forth in my copending application Serial No. 254,441' to which reference may be had for a further description of its structure and operation. It is also to be understood that the leftofi designated'at L at the left end of Fig. 6 is similar to the mechanism set forth in Fig. 7 and operates in a very similar manner through a rod 50 connected at its upper end to a lever 5! moving about a fixed pivot 52 and connected to a rod 53 attached to a lever 54 moving about a fixed pivot 55 and similar to lever 45 in that it exerts rearward force on a lug 56 moving with the left end of whip roll I4. It will therefore be seen that rocking of lever 54 in a left hand direction when beam l4 moves forwardly due to warp tightening will lift rod 50 to letofi" of warp from beam W.

As previously intimated the whip rolls are movable backwardly and forwardly in response to variation in tension of the warp threads passing over them. Horizontal motion of the whip rolls may be provided for by the mountings shown for instance in my co-pending application Serial No. 279,712, and I will describe these mountings with respect to roll [3 with the understanding that whip roll M has the same kind of mounting.

Referring particularly to Fig. l, a bracket 60 is securedto the left end of the roll l3 and carries a vertical pivot pin 6! for a link 62. The latter is pivoted as at 63 to a second link 64 moving about a fixed vertical pivot 65 carried by a stationary support 66 forming part of the loom frame. The pivots 6|, 63 and 65 are relatively large and sufiiciently strong to support the whip roll for movement in a' horizontal direction.

The right end of whip roll [3 is provided with a roller bearing support designated generally at R, see Figs. 1 and 5. This support includes a foot ill having depending rails H which are vertically above other rails 72 carried by a stationary support 13. Between each pair of rails H and i2 is located a roller bearing in the form of a chain C l'iaving rolls 74 between the upper and lower rails and having side links l5 which connect the rolls '14 together and also engage the sides of the rails H and 12 to prevent objectionable lateral motion of whip roll l3 in the direction of a length thereof. The foot Hi carries a previously described lug 48 which cooperates with lever 45 as already described. The motmting for the left end of whip roll I4 is similar to that already described in connection with the right end of whip roll I3, the previously described-lug 55 being carriedby a foot 15 similar to foot '10 resting on structure corresponding to that-already described in connection with foot ill.

The link support for the adjacent ends of the whip rolls l3 and I 4 are associated with levers ii? and 68, respectively, movable about fixed pivots E9 and exerting rearward force on the bracket through an adjusting screw 71.

For a more detailed description of the mounting for the ends of the whip rolls reference may be had to my co-pending application Serial No. 279.712 and it is thought sufiicient for present purposes to state that the whip rolls are mounted to move toward and from the front of the loom and that forward motion of whip roll I 3, for instance, is associated with a counter-clockwise rocking of levers 45 and 61 when the warp threads become tight and that the whip roll is moved rearwardly by pressure exerted by these levers 45 and .67 when they are turned in a clockiwise direction by a weight to be described. Similarly whip roll 14 moves in response to warp tightening to effect rocking of levers 54 and 68 and is likewise movable rearwardly by a rocking of these last named levers in the opposite direction.

As previously stated the warps W and W are destined for incorporation into a single factor and the tensions on these two systems of war, threads should therefore be equalized so that the resultant fabric will be free from internal strains such as would result if one set of warp thTeEds were tighter than the other. In my Patent No. 2,184 059 there is shown a weight which is raised when the whip roll moves forwardly due to tightening the warp threads, this weight being released when the escapement pawl is unlocked and effec- Give to move the whip roll rearwardly. I use a similar weight in the present instance but instead of having an individual weight for each of the two letoff mechanisms L and L which might result in uneven control of the whip rolls l3 and I4 I employ a single weight and connect it to the structure already described in such a way as to equalize the forces exerted on the two whip rolls.

In carrying the preferred form of my invention into effect I provide a lever 86 moving about a fixed pivot 8| and having a horizontal arm 82 which supports a variable weight 83 at different distances from the pivot 8|. A vertical arm 8 of lever 82 carries a sheave 85 turning on a stud St on the arm. Trained around this sheave 85 is a flexible cable 8! the upper section 88 of which controls the whip roll l4 while the lower section 89 thereof controls the whip roll I3.

The left end of the upper section 88 of the at a faster rate than would whip roll corresponding whip roll.

left end of. the .l'oom'as viewed in Fig. 1 and'this section vis also connected to lever 68 by a head 9] :pivoted to the lever 68 and having the cable secured thereto. The left end of the lower section 89 of the cable is connected as at to lever 61 and has also a head 95 similar to head 3! connectedito lever 45 at 91.

In operation, thewarp will be consumed during normal weaving operations in the usual manner. When the beams are locked against rotation'the continuing demand for warp threads will be met byforward motion of the whip rolls. When the whip rolls move forwardly'they act through lug 48, screws 11 and lug 55 to turn the levers 45. 61, 58 and 54, respectively in a counterclockwise direction, see Fig. 1. The left ends of both ca'b'le sections BilandBS will move to the left as will also sheave 85 with resultant lifting of the Weight 83 Levers 45 and 54 will raise rods '36 and 55, respectively, to release the escapement mechanism lock shoes 34 at both ends of the loom, whereupon the beams turn due to the force exerted on them by the warp threads. As the warp is fed from the beams the pressure-exerted on the whip rolls is reduced and the latter are moved rearwardly by a right hand angular motion of levers 45, 61, 68 and 54 induced'by weight 83. This rearward motion of the whip rolls is accompanied by motion of the cable seetions 88 and 89 to the right, Fig. 1, and the lever 84 is therefore temporarily free to rock in a right hand direction as viewed in Fig. 6 under action of the weight 83. The right hand rotation-of levers 45 and 54 results in lowering their respective rods 35 and 50 which ultimately :causes shoes 34 to engage rims 35 to stop further rotation of the beams. This operation occurs repeatedly during the running of the loom.

ilO

whip rollsadvancing when the warp beams are tight to effect unlocking of the escapement. and then moving rearwardly under action of the weight 83 when the beam is unlocked and turns to supply warp.

'If the condition of beam II should be such that a given angular movement thereof would supply more than the same angular movement of beam 12, whip roll l3'would move rearwardly M with the result that the escapement corresponding to beam I! would be locked before locking of the escapem'ent for beam l2. The latter escapement would therefore continue to oscillate after beam ll had been locked, since the locking of each escapement depends upon the position of the When beam 'l! is locked rearward motion of the whip roll 13 ceases and therefore the lower strand or s ct on -89 of the cable becomes temporarily stationary. Under the assumed. condition whip rail #4 will continue to move 'rearwardly and the upper strand 88 of the cable continues to move to the right due to the fact that sheave '85 is freet 1 turn on lever -84 and the latter continues to rock ina right hand direction because of weight 83. Whenbeam l2'is ultimately locked whip rol Hi comes temporarily'to'rest and then-starts forward with whip roll 13 which has already start ed to advance. Cable strands 88 and 89 there-- foremove to the left due to advance motion of the whip rolls and there is a corresponding lifing of weight 83.

If whip roll 14 should move forward at arate faster than that of whip roll I3, the escapement for beam l2 will unlock whilethe escapement of -:-beam H .is stillllocked and whip'rolll 4 willr's'tart to move rearwardly. Under these conditions the upper strand 88 of the cable will move to the right under action of weight 83 while the lower strand will be held against motion to the right and will actually be moving to the left because whip roll I3 is still advancing. Whip roll I4 therefore starts to move rearwardly while whip roll I3 is advancing and the escapement at the left end of the loom will be locked when the whip roll I4 reaches a predetermined rearward position regardless of the motion of whip roll I3.

The corresponding arms of the levers 45, 01, 68 and 54 are substantially equal so that the forces exerted on the whip rolls I3 and I4 by the single weight are substantially the same. I do not deem it essential that all of the levers just mentioned shall be of the same size, but the proportions of the levers should be such that the forces exerted on the whip rolls will be equal.

I am not limited to the use of a cable and a sheave as shown in the preferred form of the invention already described and where it is desired to use rigid connections I may employ the modified structure set forth diagrammatically in Fig. 13. It is to be borne in mind that the whip rolls move back and forth through a comparatively short distance between locking and unlocking positions for the letoff and for this reason I can use a floating lever I pivoted as at IN to a lever I02 which corresponds to lever 80 in the preferred form. As shown in Fig. 13 the upper arm I03 of lever I00 is connected to a rod I04 extending to the left and attached by means of a rod head I05 to a lever I06 corresponding to lever 68. From the rod head I05 a second rod l0! extends to the left to be connected as at I08 to a lever I09 corresponding to lever 54. Levers I06 and I09 have force communicating connections with the whip roll M at I I0 and I I I, respectively, in a manner similar to that of the preferred form.

The lower arm H5 of lever I00 is attached to a rod IIB connected to a rod head II'I pivoted on a lever I I8 corresponding to lever 45 already described, and a rod II9 extending to the left from the rod head I I7 is connected as at I20 to a lever I2l corresponding to lever 61. Levers H8 and IEI have force transmitting connections I22 and I23, respectively, with the whip roll I3.

The operation of the modified form is quite similar to that already described in connection with the preferred form. When the whip rolls move forwardly the levers I06, I 09, H8 and IZI, are rocked in a counter-clockwise direction and therefore exert left hand pulls on the rods attached to them, with the result that the floating lever I00 is moved to the left and the lever I02 is turned in such a direction as to raise a weight I25 corresponding to weight 83. On the other hand, when the whip rolls have reached their forward position and have effected unlocking of their respective letoif mechanisms, the lever I02 turns to the right to exert a force on the rods I04 and H6 and also on rods I01 and H9 directed to the right'and tending to rock the levers connected to the rods in a right hand direction and cause rearward movement of the whip rolls.

Should either whip roll in the modified form move at a rate different from that of the other whip roll, or move in a direction opposite to the motion of the other whip roll, the operation will be substantially the same as that already described for the preferred form, the essential difference being that in the modified form the lever I00 will rock on its pivot IOI whereas in the preferred form the sheave would rotate. As will be apparent from Fig. 13 whip roll I3 may move forwardly to cause left hand motion of arm '5 while whip roll I4 can move rearwardly, which corresponds to a right hand motion of arm I03. The weight I25 acts constantly to keep the connections between lever I02 and the whip rolls tight and in force transmitting relationship.

Fig. 13 has been restricted to the changes necessary to use rigid rods as substitutes for the cable and a lever as a substitute for the sheave in the preferred form, but it is to be understood that the connections to the letofi mechanisms will be the same as in the preferred form, levers I09 and H8 controlling, respectively, the-letoffs for the left and right hand sides of the loom.

A feature to be noted in connection with the modified form of the invention is that levers I06 and I09 need not necessarily be the same as levers H8 and I2I. In fact, the ratio of the arms for the levers of the left hand whip roll I4 can be different from the ratios of the arms for the other whip roll I3, the difierence in ratio being made up by the difference in length of the arms I03 and H5 of the lever I00.

From the foregoing it will be seen that I have provided a simple control for two independently acting letoff mechanisms for two separate beams, whereby each beam and its whip roll can move in response to variations in warp tension of the associated system of Warp threads independently of the mechanism acting on the other system of warp threads. Also, uniformity of tension is insured because both systems are acted on by the same weighted member. The levers which control and in turn are controlled by the whip rolls are so proportioned that the weight 83 exerts equal restraining forces on the whip rolls when the latter advance, and exert equal actuating forces on the rolls when the latter are to be moved rearwardly. It will also be seen that the principles of my invention and the advantages to be derived from it can be achieved as set forth in the modified form of the invention by a floating lever mounted on the weighted member and having rigid connectors extending to the various levers which are moved by and in turn effect movement of the whip rolls.

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 loom having a pair of warp beams each to supply a part of the warp to be incorporated into a single fabric being woven by a loom, the loom having a whip roll for each beam movable independently of the whip roll for the other beam and having a letoif mechanism for each beam capable of locking and unlocking the corresponding beam, and having connections between each whip roll and the corresponding letoff mechanism by which the latter is unlocked to permit rotation of the associated warp beam when the corresponding whip roll is forward and by which the letoff is locked to prevent rotation of the associated warp beam when the corresponding whip roll is rearward, that improvement which comprises a single weighted member for both Whip rolls, and equalizing connections between the weighted member and the two whip rolls to cause the weighted member to exert the same resisting force on each whip roll when the latter tends to move forwardly and causing the weighted memaeomog bar to exert the same force'on each whip roll to move the latter rearwardly.

2. In a loom having a pair of warp beams each to supply a part of the warp to be incorporated into a single fabric-being woven by a loom, the loom having a whip roll for each beam movable independently of the whip roll for the other beam and having a letoff mechanism for each beam capable of locking and unlocking the correspond-,

ing warp beam, and having connections between each whip roll and the corresponding letoff'mechanism. by which the latter is unlocked to permit rotation of the associated warp beam when the corresponding whip roll is forward and by which the letoif is locked to prevent rotation of the associated warp beam when the corresponding whip roll is rearward, that improvement comprising a single weighted member for both whip rolls requiring the application of force thereto to be moved in one direction and tending constantly to move in the opposite direction, a connection from each whip roll to the weighted member by which each whip roll tends to move the weighted member in said one direction when moving forwardly and by which the weighted member exerts a force in the said opposite direction tending to move the whip roll rearwardly, and an equalizer between the connections and the weighted member to cause the latter to exert equal forces on the connection.

3. In a loom having a pair of warp beams each to supply a part of the warp to be incorporated into a single fabric being woven by a loom, the loom having a whip roll for each warp beam movable independently of the whip roll for the other warp beam and having a letoff mechanism for each warp beam capable of locking and unlocking the corresponding beam, and having connections between each whip roll andthe corresponding letoff mechanism by which the latter is unlocked to permit rotation of the associated warp beam when the corresponding whip roll is forward, and by which the letoff is locked to prevent rotation of the associated beam when the corresponding whip roll is rearward, that improvement comprising a single weighted member for both whip rolls requiring the application of force thereto to be raised and tending constantly to move downwardly, connections between the whip rolls and the weighted member by which each whip roll tends to raise the weighted member when moving forwardly and by which the weighted member in tending to move downwardly tends to exert a force acting to move the whip roll rearwardly, and an equalizer in the connections between the whip rolls and the weighted member to cause the latter to exert equal forces on the whip rolls.

4. In a loom having a pair of independently rotatable warp beams and having a movable whip roll for each beam, a letoff mechanism for each beam to be locked to prevent turning of the corresponding beam by movement to a given rearward position by the associated whip roll and to be unlocked to permit turning of the warp beam by forward movement to a predetermined forward position by the whip roll, that improvement which comprises a single weighted member for both letoff mechanisms, and equalizing connections between both whip rolls and the single weightedmember, the weight acting through said connections to exert equal forces on the whip rolls tending to move the latter to said given position and said connections tending to raise the weighted member when either whip roll moves forwardly.

to be unlocked to permit turning of the warp beam by forward movement to a;predetermined forward position ,by the whip roll, that improvement which comprises a single weightedimember for both whip rolls, a pulley moving, with and rotatablegrelatively to the weighted member, a cable the intermediate part between the ends of which. is trained around thepulley, and means to connect one end of the cable to one whip roll and the other end of the .cable to the other whip roll, motion of either whip roll toward the predeterminedforward ,positionbeing resisted by the single weighted member by a force transmitted through the cable, andtheweighted memher acting through the cableto move either whip roll toward the given rearward position.

6. In a loom having ,a pair of independently rotatable warp beams and having a movable whip roll for each beam, a letoif mechanism for each beam to be locked to prevent turning of the corresponding beam by movement to a given rearward position by the associated whip roll and to be unlocked to permit turning of the .warp beam by forward movement to a predetermined forward position by the whip roll, that improvement comprising a lever for each letoff mechanism movable in one direction to lock the corresponding warp beam,v a single weighted member, flexible equalizing connections between the single weighted member and each whip roll to transmit a force from the weighted member to either rollto resist forward movement thereof and transmitting a force from each whip roll when the latter movesforwardly'to the weighted member tending to raise the latter, and a con.- nection between each whip roll and the corresponding lever to move the latter to unlock the letoff connected thereto when the corresponding whip roll moves forwardly to said predetermined position and to move the lever in the opposite direction when the corresponding whip roll moves rearwardly to saidgiven position to lock the letoff mechanism connected thereto.

'7. In a loom having a pair of independently rotatable warp beams and having a movable whip roll for each beam, a letoff mechanism for each beam to be locked to prevent turning of the corresponding beam by movement to a given rearward position by the associated whip roll and to be unlocked to permit turning of the warp beam by forward-movement to a predetermined forward position by the whip roll, that improvement comprising a single movable weighted member for both whip rolls, connections between the whip rolls and the weighted member including elements extending from the weighted member toward each whip roll, and movable with and by the weighted member and the whip rolls, means connecting each whip roll and the element corresponding thereto to cause each whip roll when moving forwardly to exert a force through the associated element on the weighted member tending to lift the same, and each element transmitting a force from the weighted member through the corresponding means tending to cause rearward movement of the associated whip roll, and an equalizer connecting the elements to the weighted member and acting tov cause the latter to exert equal forces on the elements and acting to cause either element to lift the weighted member when moving toward said predetermined forward position.

8. In a loom having two independent warp beams each supplying part of the warp thread which is incorporated into the fabric being woven in the loom, a letoif mechanism for each warp beam, each letoff mechanism capable of locking the beam corresponding thereto against rotation and also capable of releasing the corresponding beam to permit rotation thereof due to tension of the warp thereof, a whip roll for each warp beam, the warp thread of each beam extending over the corresponding whip roll and tending to move the latter forwardly when the associated warp beam is locked against rotation, control connections between each whip roll and the letoff mechanism corresponding thereto to unlock the associated beam when the corresponding whip roll reaches a given forward position, a single weighted member for both whip rolls, a train of mechanism extending from each whip roll toward the weighted member, equalizing connections between said trains of mechanism and the weighted member to cause the latter to exert equal forces on the train, each whip roll when moving forwardly acting through the train corresponding thereto to exert a lifting force on the weighted member through the equalizer, and the weighted member acting through the equalizer and the train of a whip roll which is in said given forward position tending to move the latter rearwardly to tension the warp of the corresponding warp beam during rotation of the latter due to releasing thereof by the associated letofi mechanism.

9. In a loom having two separate warp beams each supplying a part of the warp thread to be incorporated in the fabric being'woven by the loom, a whip roll for each beam, a letofi mechanism for each beam controlled by movement of the corresponding whip roll, the warp thread of a beam extending over the corresponding whip roll and tending to move the latter forwardly, means controlled by each whip roll when in a given rearward position to cause the letoif mechanism corresponding thereto to lock the associated warp beam against rotation, other means to cause each whip roll to unlock the corresponding letoif mechanism to permit the associated warp beam to turn under tension of the warp thread thereof when the whip roll reaches a predetermined forward position, a single weighted mem her for both whip rolls, a train of mechanism ex tending from each whip roll toward the weighted member, an equalizer between the trains of mechanisms and the weighted member to cause the and the weighted member acting through the equalizer and the train of a whip roll which has reached said predetermined forward position effective to move the whip roll toward said given rearward position during rotation of the associated warp beam, each whip roll movable ,toward and from said given rearward and predetermined forward positions independently of the other whip roll and the equalizer being capable of transmitting a lifting force on the weighted member from one of said trains when the corresponding whip roll is moving forwardly and simultaneously transmit a force from the weighted member to the other whip roll tending to move the latter rearwardly.

10. In a loom having a pair of independently rotatable whip rolls each supplying a part of the warp thread to be incorporated into the fabric being woven by the loom, a letoff mechanism for each beam, each letoif mechanism capable of locking the corresponding beam to prevent rotation of the latter and capable of unlocking the corresponding beam to permit rotation of the latter due to tension of the corresponding warp thread, a whip roll for each beam, each whip roll movable forwardly to a predetermined position by tension of the corresponding warp thread when the associated warp beam is locked, means operated by each train when the corresponding whip roll reaches said predetermined position to cause the corresponding letoff to unlock the associated warp beam, a single weighted member, a train of mechanism for each whip roll extending toward the weighted member, an equalizer connecting the trains of mechanism and the weighted member to cause the latter to exert equal forces on the trains, each whip roll when moving to said predetermined position having the forward motion thereof resisted by the weighted member acting through the equalizer and the corresponding train, each train-capable of transmitting a lifting force from the corresponding whip roll to the weighted member through the equalizer when the associated warp beam is locked, and each train transmitting a force from the weighted member through the equalizer to the corresponding whip roll tending to move the latter rearwardly when the associated warp beam is unlocked.

OSCAR V. PAYNE.

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