US2707973A - Control for loom letoff - Google Patents

Description

May 10 1955 A. J. HERARD, JR

CONTROL FOR LooM LETOFF Filed March 9, 1954 "Illl" "IIU'HIIUIIWH"Illllllllllllll' lll Mw. www@ ATTORNEY INVENTOR ARCHIBALD J. HERARD JR.

Unite States Patent C CNTR'OL FR LOOM LETOFF Archibald J. Herardwlr., Worcester, Mass., assignor to Crompton & Knowles Loom Works, Worcester, Mass., a corporation of' Massachusetts Application March 9, 1954, Serial No. 414,971

11 Claims. (Cl. 139-111) This invention relates to controls for loom let-off mechanisms and it is the general object of the invention to provide means employing preferably rotatable friction means to engage some part of the let-oll mechanism to serve as a brake to prevent it from paying olf warp incident to loom stoppage.

A let-olf mechanism in common use employs a train of gearing including an escapement device one part of which oscillates so that another part thereof can turn to permit movement of the gearing and thus allow warp to be paid oif. It has been found that under certain conditions ot' operation stoppage of the loom will cause the oscillating part of the eseapement mechanism to have undesired movements when there is no need for movement resulting in an excessive paying off of warp which reduces its tension below the permissible minimum.

lt has been proposed heretofore to prevent excess motion of the oscillating part of the escapement mechanism by the addition thercinto of a relatively heavy weight which acts during loom operation to dampen vibration of the oscillating part, and it has further been proposed to apply a brake to the weight or some part moving with it when the loom stops.

lt is an important object of the present invention to provide a brake means for the oscillating part of the escapement mechanism utilizing a rotatable friction surface which due to successive engagements with said part will turn to present fresh surfaces thereof to the weight and thus reduce wear of the surface.

lt is a further object of the invention to mount friction rings rotatably on an eccentric which is normally spaced from the weight in non-braking position but is rocked to move the rings against the weight incident to loom stoppage, engagement of the weight with the rings turning the latter on the eccentric.

lt is another object of the invention to use friction such as leather or brake material which is slightly compressible so that upon engagement with the weight it will not only arrest oscillation of the latter but will also due to its compressibility have a slight rolling relation with the weight and turn to present fresh surfaces to the weight.

It is another object of the invention to provide a variation of the foregoing wherein the friction surface is on a rotatable roll mounted to move against the weight upon loom stoppage and be turned on its axis due to engagement with the weight.

ln order that the invention may be clearly understood reference is made to the accompanying drawings which illustrate by way of example two embodiments of the invention and in which:

Fig. 1 is a side elevation of the rear part of a loom having the preferred form of the invention applied thereto,

Fig. 2 is an enlarged horizontal section on line 2 2,

Fig. l,

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Figs. 3 and 4 are vertical sections on lines 3-3 and 4 4, respectively, Fig. 2,

Fig. 5 is a vertical section on line 5 5, Fig. 4,

Fig. 6 is a fragmentary side elevation looking in the direction of arrow 6, Fig. 2,

Fig. 7 is a diagrammatic View similar to Fig. 3, but showing the eccentric moved to braking position,

Fig. 8 is a diagrammatic View of electric circuits which may be utilized to control means which are associated with the eccentric, and

Fig. 9 is a diagrammatic view similar to Fig. 4 showing a modiiied form of the invention.

Referring to Figs. l and 8, the loom frame 1 has a shipper shaft 2 and a shipper handle 3 thereon to control operation of the loom. A rod 8, shown diagrammatically in Fig. 8, extends rearwardly from handle 3 to an electric switch S which may be of any approved construction. As shown in Fig. 8 the shipper handle as shown in full lines in running or driving position with the switch will be closed, but when the loom is stopped the shipper handle will be moved to the dotted line position shown in Fig. 8 with resultant opening of switch S.

Behind tl e loom is an upright 1) which together with the loom frame supports a channel iron 11 having a Vertical web 12 and top and bottom flanges 13 and 14, respectively. Secured to the llange 13 and extending upwardly therefrom is a casing l5 containing a nest of gearing operatively connected to the warp beam B which is journaled at 15 for rotation on a stand 17 secured to the upright 1li. The beam has secured thereto a sprocket wheel 18 meshing with a chain 19 engaging an adjustable idler 20 and then extending upwardly and around a sprocket wheel 21 rotatable on the casing 15. Fixed with respect to the sprocket wheel is a gear 22 which meshes with a pinion 23 rotatable on the casing and fixed with respect to another gear 24 which in turn meshes with a pinion 2S.

The casing 15 supports an escapement means, designated generally at E, including an escapement wheel fixed with respect to and turning with pinion 2S and including also an oscillating member 31 the pallet or double pawl 32 of which cooperates with the wheel 3:6. The oscillating member 31 is pivoted to the casing 15 at 33 and has la part 34 thereof extending downwardly for attachment to a dampening weight 35. The latter is secured to the part 34 by a bolt 3o and is provided primarily to dampen excess vibration of member 31. The pallet 32 and parts 34 and 35 may be considered as the oscillating part ofthe escapement mechanism E.

The loom has 'a stationary warp guide roll 40 and `a whip roll 41 mounted on a lever 42 the upper end of which is pivoted as at 43 to a small support 44 lixed with respect to the casing 15. A connector 45 attached at the lower end of lever 42 extends forwardly and is connected to a lever 46 which in turn is connected to a lever 47 pivotally mounted on a stationary stand 48. The lever 47 is connected to the lower end of an upwardly extending rod 49 having secured thereto a collar 56 to engage a brake member 51. The upper end of the rod 49 is surrounded by a compression spring 52 and passes through a guide stand 53 secured to the top of the casing 15. The brake member 51 has a shoe 55 for engagement with an arcuate brake 'ange 56 on the part 34 and concentric with axis 33. The warp W extends from the beam B over the guide and whip rolls and then forwardly to provide the upper and lower warp sheds Wl and W2, respectively.

In operation, when the warp tension is at or near 'the permissible minimum the whip roll will be in rear position, to the left in Fig. 1, and the rod 49 will be down so that spring 52 can hold the shoe 55 against the brake ange 56 and prevent oscillation of member 31. The escapement wheel is thus held against rotation and the gearing and the chain 19 operatively connected to it are held stationary to prevent angular movement of the warp beam. Consumption of the warp during the weaving increases its tension and the whip roll moves forwardly, the result of which through connector and lever 46 causes upward motion of rod 49 to cause movement of the shoe away from the flange 55. The member 31 will then be free to oscillate to permit the beam to rotate clockwise, Fig. l, to pay of; sufficient warp to reduce the warp tension. During the warp paying oif operation the oscillating part of the escapement mechanism rocks back and forth around the pivot 33 and this rocking will bc arrested when the warp tension again approaches its permissible minimum to allow the shoe 55 to engage the lange 56.

The channel iron 11 has secured thereto a unit U including a carrier 59 provided with two bearings 60 and 61 which are located respectively in front and back positions as viewed in Fig. 1. These bearing members support a shaft 62, to which is secured an elongated eccentric member 63 extending closely adjacent to the path of oscillation of the weight 35. Ordinarily the eccentric will be disposed as shown in Fig. 3 during loom operation.

The means for holding the eccentric in its normal nonarresting position, Fig. 3, during loom operation includes an electromagnetic device shown here as a solenoid held in any approved manner to the forward bearing 60. The solenoid is supported by a holder 71 having a plate 72, see Fig. 2, bolted at 73 to the bearing 60 and includ ing a forward upright arm 74 and a cross bar 75 extending over the solenoid and connected to a depending arm 76. The lower ends of the arms 74 and 76 extend part way under the solenoid as at 77, and the holder 71 fits the solenoid closely enough to hold it in rigid position.

The solenoid has a core which is pivoted at 81 to a link 32 the lower end of which is pivoted at S3 to an arm 84 which is freely rockable on a stud 85 secured to a bearing 60, as by being pinned thereto at 86, see Fig. 6. The hub 87 of arm S4 receives one end 88 of a torsion spring 89 surrounding stud 85 and having the other end 90 thereof extended into a collar 91 held in angularly adjusted position on the stud 85 by set screw 92. The effect of the spring is to tend to turn the arm 84 in a counter-clockwise direction as viewed in Fig. 4, but the spring will ordinarily be overpowered vby the solenoid which is energized during loom operation. A second arm 93 is secured by set screw 94 to the shaft 62 and has a pin 95 thereon extending into a slot 96 in the arm 84. A manually controlled electric switch M is supported by the bearing 60 and has a small handle 97 by which it can be moved temporarily from its normally open position to closed position.

Solenoid 70 and the switches S and M are electrically connected as indicated diagrammatically in Fig. 8. A source of electric power P such as a transformer is connected by wire 99 to one side of the solenoid and the other side of the latter is connected by a wire 100 to a pole 101 of the switch S. The other pole 102 of switch S is attached to but insulated from the rod 8 and is connected to the opposite side of the power source P by wire 103. The normally open switch M is in parallel with the switch S by having its electrode 105 connected to wire 100 and having its other electrode 106 connected to wire 103. The solenoid 70 and spring 89 and the parts associated with them serve as control means for the eccentric 63 and the latter, to be described more fully hereinafter, may be considered to be a support means for parts to be described movable about an axis toward and from the weight 35 and the path in which it swings.

The letoff proper may be similar to letolis shown in several prior patents, one of which No. 2,330,514 to Payne may be mentioned as an example, and the eccentric 63 and parts connected to it may be similar to structure and circuits previously proposed and shown, for instance, in copending application Serial No. 399,452, filed December 2l, 1953, by Laraia and Sepavich. It is thought sui'icient for present purposes to state that the escapement means E operates when the brake 51 is in the non-braking position to permit the beam B to turn and that if under these conditions the loom should be stopped there is likely to result a sufficient vibration to cause undesired oscillation of the member 31 which may result in paying off more warp than is desired.

The present invention relates more particularly to the part of the arresting means which has direct engagement with the weight 35. Two forms are shown herein, the tirst and preferred of which utilizes the eccentric already described. The aim of the preferred form of the invention is to provide a surface for the eccentric which shall be rotatable thereon for the purpose of distributing wear of the surface and also to present new or fresh surfaces to the weight.

Referring particularly to Fig. 5 collars 110 and 111 are secured to the right and left hand ends, respectively, of the eccentric and held in adjusted position along the eccentric by set screws 112. Between the collars are located circular friction members 113 alternating with spacers or washers 114. The members 113 are in the form of rings having external surfaces 115 of circular shape and the collars 110 and 111 are so located that the friction members 113 are rotatable on the eccentric but held against substantial endwise movement on it. The spacers are of less diameter than the members 113 and do not engage the weight 35. The surfaces 11S may be considered collectively as presenting friction surface means rotatable about the eccentric which in turn serves as support means movable toward and from the weight 35. The members 113 are, however, individually rotatable on the eccentric and only those which directly engage the weight will be acted upon to turn. The weight 35 will ordinarily be an unfinished casting and will have a more or less rough surface to be engaged by the members 113. The ring members 113 are made of friction material which may also though not necessarily be compressible, such as leather or brake material.

When the loom is in operation and the shipper handle is in the driving or running position the switch S will be closed as indicated in Fig. 8 and the solenoid '70 will be energized so that the core 80 will be raised to hold arm 84 in its elevated position against the ac tion of spring 89. When in this position arm 34 holds the arm 93 in the position shown in Fig. 4 to maintain the eccentric 63 in the non-arresting position thereof shown in Fig. 3. As soon as the shipper handle is thrown to the off or stopping position, see dotted lines Fig. 8, electrode 102 moves away from electrode 101 and the circuit for the solenoid is open, whereupon the spring 89 turns the arm 84 in a counter-clockwise direction, Fig. 4, to rock arm 93 in a clockwise direction to turn the eccentric around its axis to the arresting position thereof against the weight 35 as shown diagrammatically in Fig. 7. Engagement of the friction members 113 with the weight 35 will be sufficient to arrest any oscillation of the member 31 which might otherwise occur incident to stoppage of the loom, and the escapement means is prevented from operating, thus locking the beam B against turning and maintaining a workable warp tension.

During engagement of the friction ring members 113 with the weight they are moved bodily against the weight by a force derived partly from the weight of the core 80 and partly from the spring 89. From the time the rings first engage the weight 35 until the eccentric comes to its nal position there is a slight rolling motion of the rings on weight causing the rings to turn in a counter-clockwise direction with respect to the eccentric as viewed in Fig. 7. This rotary motion of the rings is not fully undone when the eccentric is moved to its non-arresting position shown in Fig. 3, as by closure of the switch M. Slow creepage of the ring members 113 around the eccentric in a counter-clockwise direction as viewed in Fig. 7 can be demonstrated by placing a mark on the top of one of the rings and then subjecting the eccentric to repeated movements rst to braking or arresting position and then away from braking position to non-arresting position. When the eccentric is subjected to such alternating movements the mark will be observed to move away from the weight 35. This creeping of the rings 113 continually presents new surfaces to the weight 35 so that the entire surface of any ring which engages the Weight will eventually be presented to it so that wear will be distributed entirely around the ring.

If the cause of loom stoppage requires that the letoff be released the operator 'can close the switch M, whereupon the solenoid will be reenergized and the eccentric will be moved from the position shown in Fig. 7 back to the non-arresting position shown in Fig. 4. Release of the handle 97 will result in opening the switch M, whereupon the eccentric will return to arresting position.

The modified form of the invention operates on the same general principle as does the preferred form, but instead of an eccentric a simple roll is used. Referring to Fig. 9, the unit Ua includes a carrier bolted at 126 to channel iron 11 and formed with depending bearing arms 127 and 128 which support a shaft 129 rockable in the bearing arms. cured to shaft 129 have rotatably mounted on their upper ends a roll 132 to which is secured a friction surface 133 for engagement with weight 35. The arms and 131 constitute means movable about an axis toward and from weight 35 and the path in which it swings.

A shelf 135 on arm 127 supports a solenoid 136, similar to solenoid 70, having a core 137 connected by link 138 to arm 130. The latter arm is connected to a tension spring 140 the upper end of which is held to the shelf. Solenoid 136 is controlled electrically as is solenoid 70 and normally is energized to hold roll 132 in non-arresting position away from weight 35 against the action of spring 140, and the latter, upon deenergization of solenoid 136, causes the roll 132 to move to arresting position against the weight. The roll is free to turn on the arms 130 and 131 and rotates around its axis as do the ring members 113.

From the foregoing it will be seen that the invention sets forth means for arresting undesired oscillation of the member 34 by friction means rotatable on a support means to present fresh friction surfaces to the Weight 35. It will also be seen that the collars 110 and 111 used in the preferred form effectively prevent endwise movement of the rings 113 on the eccentric but permit them to rotate. In the modified form the friction surface is on a roll which is free to rotate. In both forms the friction part or parts, as the rings 113 or roll 132, are rotatable on support means, as the eccentric or arms 130 and 131, which are movable toward and from the weight 35 and its path of oscillation, the weight being engaged by parts of the friction surface which move in a path oblique to the weight path at the time of contact with the weight. The oblique path need not be arcuate as shown herein. The friction surfaces are of material which is preferably though not necessarily slightly compressible. The compressibility, when present, is thought to assist in the rolling of the rings and roll 132 along the Weight, and that this rolling contributes to the slow rotary creep- Arms 130 and 131 se- (rtl ing of the friction surface with respect to its support. The invention also sets forth units, as U and Ua, readily adaptable to existing looms.

Having now particularly described and ascertained the nature of the invention and in what manner the same is to be performed, what is claimed is:

l. In let-off mechanism for a loom having a warp beam and wherein oscillation of a part of an escapement means enables the beam to turn to pay off warp, support means movable toward and from said part of the escapement means to assume arresting and non-arresting positions with respect to said part, friction means for engagement with said part rotatable on said movable support means, and control means for said movable support means effective to keep the latter in the non-arresting position thereof during loom operation to enable said part to oscillate but effecting movement of the movable support means to the arresting position thereof to move said friction means against said part to prevent oscillation thereof when the loom is stopped, said friction means due to engagement with said part tending to turn on said movable support means to present different parts thereof to said part of the escapement means.

2. The let-off mechanism set forth in claim 1 wherein the support means is an elongated member and the friction means is in the form of a plurality of rings rotatable on the member. y

3. The let-off mechanism set forth in claim l wherein the support means is an elongated member and the friction means are rings rotatable on the member separated from each other by spacers on the elongated member.

4. The let-off mechanism set forth in claim l wherein the support means is an elongated member having collars secured to the ends thereof in adjusted longitudinal position thereon and the friction means are rings rotatable on the member between said collars and held against substantial endwise movement along the member by said collars.

5. The let-olf mechanism set forth in claim 1 wherein the support means is an elongated member having collars secured to the ends thereof in adjusted lengthwise position relative to the member and the friction means are rings rotatable on the member between said collars alternating with spacers of less diameter on the elongated member, the spacers holding the rings in spaced relation along the member and cooperating with the collars to prevent substantial movement of the rings lengthwise of the member.

6. The let-off mechanism set forth in claim 1 wherein the support means just prior to engagement of the friction means with said part causes the surface of the friction means which is to engage said part to move in a direction oblique to said part.

7. In a let-off mechanism set forth in claim 1 wherein the friction means is compressible and is subjected to compression at those parts thereof which engage said part of the escapement means when the support means moves to arresting position.

8. In a let-olf mechanism set forth in claim l wherein the support means comprises arms mounted for movement in unison with respect to said part of the escapement means and the friction means in a roll rotatable on said arms.

9. A unit to control the oscillating part of an escapement means of a warp let-off mechanism, said unit including a carrier, support means mounted for angular movement on said carrier, an electromagnetic device supported on the carrier, means whereby energization of the device effects turning of the support means in one direction with respect to the carrier, other means supported by the carrier tending to turn said support means in the opposite direction, and friction means mounted on the support means for rotation with respect thereto.

10. The unit set forth in claim 9 wherein the support means is an elongated eccentric and the friction means are rings rotatable on the eccentric and said other means References Cited in the file of this patent is effective upon deenergization of the electromagnetic UNITED STATES PATENTS device to rock said eccentric in said opposite direction.

comprises a roll rotatable 0n said arms.

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