US2648961A - Multifilament-responsive thread break detector - Google Patents

Description

Aug. 18, 1953 c. B. HAYES ,648,961

MULTIF'ILAMENT RESPONSIVE THREAD BREAK DETECTOR Filed July 31, 1951 2 Sheets-Sheet 1 TEXTILE OPERATION Z6 26 8 X INVENTOR.

CLYDE B. HAYES ATTORNEY Aug. 18, 1953 Fiied July 31, 1951 c. B. HAYES 2,648,961

MULTIFILAMENT RESPONSIVE' THREAD BREAK.DETECTOR 2 Sheets-Sheet 2 (3* r! h &@ sl

"' lllll IHH' "villi "'HHIIIH' INSULATION INVENTOR. CLYDE B. HAYES ATTORNEY Patented Aug. 18, 1953 MULTIFIIJAMENT-RESPONSIVE THREAD BREAK DETECTOR Glyde'B. Hayes,,Wolctt, Conn., assignor of twothirds to Harry Fleisher, Water-town, Conn., Max Doft, Cedarhurst, N. Y.,, and Harley Wilson, Watertown, Conn.

Application July '31, 1951", SerialNo. 239,448

Claims. 1

This invention relates to. a multi-filament-responsive thread break detector for'textile. machines.

By way of example the invention will be described herein with respect to a tricot knitting machine. However, it.is to be understood that this specific form of the invention only is to be considered as illustrative and the invention is nottobe deemed as limited thereby except as and to the extent to which features of such embodiment are pointed out below and are incorporated intheappended claims.

In a machine suchas a tricot machine wherein a very large number (thousands) of threadsisimultaneously are knitted,.warped, reeled or the like, it is time-consuming, expensive, cumbersome and diflicult to have av different stop-motion device associated with each thread. Hence it has been proposed to employ amulti-filamentresponsive stop-motion device which is so constructed as to be sensitive to the breakage of any one of a large number of threads for. example, any one of a largegroup of threads in a tricot machine.

In general these multi-filament-responsive thread break detectors eitherconstitute asingle element which is depressedupon.thetautening of a broken thread, or a pair of electrodeswhichare bridged by a broken thread which had been rendered conductive by impregnation. These two types of thread break detectors are comparatively. slow in operation, cumbersome, complex and not sufficiently delicate for reliable operation in conjunction with very-fine yarns.

It is an object of the present invention toprovide a multi-filament-responsive thread breakdetector which is not subject to the .foregoingdrawbacks.

More specifically it-:is .anobjectof the invention to provide a simple, .positivesacting, efficient, rapid, sensitive, foolproofand durable detector of the character described.

Other objects of. the invention. will-in:par.ti:be obvious and in part will. be pointed; out. herein.- after.

The invention accordingly consists in the: fea tures of construction, combinations of. elements and arrangements of parts which will be exemplified in the devicehereinafterdescribedi and of whichthe scope of application will be: indicated in the appended claims.

Inthe accompanying drawings in which is shown oneof the various possible embodiments =of the invention,

Fig. l is-a front-to-back sectional, and" partly schematic, view of a textile machine employing a multi-filament-responsive thread break detector constructed-in accordance with the presentinvention;

Fig. 2 is a fragmentary side view of said detector;

Fig. 3is-a fragmentary top view of the detector;

Fig. 4 is an enlarged fragmentary sectional view taken substantially along the line 44 of Fig. 3.;

Figs. 5 and 6 are enlarged sectional views taken substantially along the lines 55 and 6-6,,respectively of Fig. 4;

Fig. '7 is an enlarged sectional view takensubstantially along the line 1-1 of Fig. 3; and

Fig. 8 is an enlarged sectional viewtaken sub stantially along the line 88 of Fig. 2.

In general the invention is carried out by providing a detector including an extremely light sensing element which is mounted on a carrier that moves the element along a path of travel beheath and transverse to the path of threads fed to a multi-filament textile operation. Said element is so mountedon the carrier as to be shiftable in a direction opposite to the direction of movement of the carrier whereby when a broken or slack thread falls in front of said element the impediment to forward movement of the element offered by the thread is sufficient to cause the element to be shifted relative to the carrier. Such movement of the element is arranged to energize a circuit which stops the textile operation. Desirably, the. circuit is energized with the aid of circuit elements which are bridged by the sensing element upon shifting-thereof, said. circuit elements further constitutinga means for holding .a broken or slack thread at a suitable level in. the path of travel of the sensing element.

Referring now in detail to the drawingsthe reference numeral illdenotesa conventional textile;machine, such for instance as atricot ma-- chine, which-is constructed to operatesimultaxneously upon alarge number. of threads. Said machine typically includes one or moredriven warp beams 12 from which a. large number of threads. l4 extend. Said threads run beneath a whip roll [6 and over a .tensionbar. [8 to a, mechanism. 2.0which performs the textile. operation, e: g. knitting. Optionally, a sley bar. iliis. lo;- cated. adj acent: the region where. broken or. slack threads-are tobe detected; here shownas between the whip roll-and tension ban.

The machine H] has. associated therewitha multiefilamenteresponsive thread break detector 2.4" whose construction and operation is the subject' of the present invention; Said detector is 3 elongated and is located beneath the path of travel of all the threads M with the longitudinal axis of the detector transverse to and beneath the direction in which the threads generally extend.

The detector includes a long narrow rigid stringer bar 26 which is attached to stationary parts of the machine in such position that the bar is beneath and extends at right angles to all the threads l4, said bar being long enough for its ends to project to both sides of the path covered by all the threads. Mounted on the stringer bar is an endless flexible carrier 28, such for example as a narrow thin steel belt, having an upper and a lower reach. The upper reach is disposed above the upper surface of the stringer bar and the lower reach extends beneath the lower surface of said bar. The belt is supported for movement with its reaches located as aforesaid by an idler flanged pulley 30 at one end of the stringer bar and by a flanged rubber-faced driving wheel 32 at the opposite end of the bar. The pulley 30 is pournalled in adjustable side plates 34 and the wheel 32 in side plates 35.

A gear 38 rotatable with the driving wheel 32 is in mesh with a pinion 40 driven by a suitable prime mover such for example as an electric motor (not shown). The electric motor continuously moves the upper reach of the belt in a direction indicated by the arrow A. Said belt is maintained in proximity to the upper and lower faces of the stringer bar by guides 42 constituting angle-shaped brackets having legs overhanging the longitudinal edges of the belt.

A pair of electrically non-conductive blocks 44 are attached to the stringer bar near one end thereof on opposite sides of the bar. A similar pair of electrically non-conductive blocks 45 are attached in like fashion to the bar near its opposite end. The distance from one pair of blocks to the other exceeds the width 0. (Fig. 2) of the path traversed by all of a group of threads whose breakage is to be sensed by the detector 24, the bar 26 being so located that one pair of blocks 44 is beyond one side of said path and the other pair of blocks 46 is beyond the other side of said path.

The blocks project above the upper surface of the bar and are provided with suitable means, such for example as posts 48, to support a pair of parallel, elongated, slender, electrically conductive rods The rods lie in a common horizontal plane and desirably are spaced symmetrically with respect to the longitudinal axis of the stringer bar. The upper sides of the rods are bare, i. e. uninsulated, so that if an electrically conductive element is laid athwart the rods, current will pass from one rod to the other. The ends of each rod are supported by the posts 48 that are located on the same side of the longitudinal axis of the stringer bar as the rod so that the rods define an open-ended long narrow space (see Fig. 3).

The outer surface of the steel belt carries a set of sensing elements 52. Said elements are uniformly spaced apart along the length of the belt and are aligned paralled to the longitudinal axis of the bar. In the preferred form of the invention the sensin elements are so located on the belt that the centers of said elements travel along a line coincident with the center of the space between the rods 50.

The longitudinal spacing between the sensing elements is determined by the speed of travel of the belt and by the rapidity with which it is desired to have a broken or slack thread sensed. Highly satisfactory results have been secured where the sensing elements are spaced apart longitudinally about six inches and the speed of travel of the belt is ten feet a minute. This arrangement insures the passage of a sensing element beneath any given thread once every three seconds.

Each sensing element comprises a shank 54 having a transversely extendin electrically conductive head 56 at its distal end. Said head may be of any suitable shape and preferably includes upwardly inclined portions extending outwardly from, and to both sides of, the distal end of the shank. In the embodiment of the invention here shown the overall transverse dimension of the head must exceed the space between the rods 50. The distal end of the shank 54 and center of the head 56 are centrally located with respect to the rods 50.

Means is included to mount the proximal end of each shank 54 for rotation about a horizontal axis transverse to the path of travel of the shanks. Said means simply may comprise a laterally offset arm 58 formed at the lower end of the shank and rotatable in a horizontal transverse bore 50 formed in a link 62. It is desirable for the bore to be somewhat larger in diameter than the diameter of the arm and for the length of the bore to be slightly less than the length of the arms in order to permit a limited sidewise shifting and rocking play of the head 56 of the sensing element. The reason for this shortly will be apparent.

In accordance with a critcal feature of the invention said sensing element, i. e. a shank 54 and head 56, is extremely lightso light that even a fine thread lying in the path of travel of the shank will so impede movement of the sensin element that it will swing about its horizontal axis of rotation on the link. To this end the sensing element is fabricated from extremely thin metal wire and has an almost negligible weight. A typical sensing element of the shape shown in the accompanying drawings is about one inch high and has a weight of about onetenth of a grain, e. g. 0.0085 gram. The illustrated diameter of the wire is exaggerated for the purpose of illustration.

Each link 62 is pivotally secured by a horizontal pin 64 to a different block 66 that is rigidly attached, as by welding, to the outer surface of the steel belt 28. The link is considerably heavier than the sensing element 52 so that, regardless of the position of said sensing element, the link will lie flat when it is on the upper reach of the belt and will dangle from the block 68 (see Fig. 2) when it is on the lower reach of the belt.

The link is provided with an upstanding support 68 against which the shank 54 of the sensing element rests when said sensing element is in operative, i. e. unactuated, position, the same being indicated by the reference character I) on the upper reach. The support is so located with respect to the pivotal axis of rotation of the sensing element that in such unactuated position the center of gravity of the sensing element is forward of said axis, forward denoting in the direction of movement of the upper reach of the belt indicated by the arrow A. Thus the sensing element when in unactuated position is in stable equilibrium, being pivotally mounted at its proximal end and having its shank inclined forwardly and resting intermediate the ends thereof on the support 68. The shank is sufliciently long so that acme-oer 5 when" the sensing element is in unactuatedposition its transversely elongated head 56 is above and' out of contact with the rods 50.

If anythread I4 slackens or is broken it will drop on the detector and will lie on and athwart the rods 50 in the path of travel of the sensing elements (see the dotted line position of a broken thread in Fig. 1). Upon reachingsucha loose thread a sensing element because of its extremely lightweight will'be-impeded and thereby caused to swing about its pivot on the link in a. rear warddirection (opposite to the direction indicated by the arrow A). As the sensing element swings rearwardly it will quickly reach a position in which its center of gravity is directly over its pivot. Thereafter the sensing element will fall under the influence of gravity and/or the further. impeding action of the loose thread until the head-58 engages the rods 5i! (position indicat'ed-by dot-and-dash Zines in Fig. 2) thereby forming an electric connection between them. Inorder for the loose thread to exert maximum torque on a sensing element the upper sides of the rods are at a level slightly belowthe distal end'of a shank in actuated position.

The rods are series-connected in an electric sensitive relay circuit (not shown), the energizationof which by bridging the rods with a conductor= will operate a device for de-energizing the motor that drives the machine It.

Although it is within the scope of the invention tohave the sensing elements travel along the return, i. e. idle, reach, in an erect position leaning in the direction of travel but too low to be engaged by a loose thread, in the detector shown herein the sensing elements traverse the idle reach in an inverted position d as shown in Fig. 2.

When the sensing elements pass around the idler pulley 30 and thereby are erected, they will bedisposed in a position e (Figs. 2 and 4) in which their heads 56 would engage the rods 59. It is essential to shift the sensing elements from such a'position e to their unactuated-position b and suitable means is provided for this purpose. Such'means comprises a cam follower 10 on each link (see Figs. 3 and 5), the same constituting a pin extending transversely away from both sides of'the link. Said cam follower cooperates with a cam 72 including a pair of cam elements l4, l6 one located on each side of the stringer bar between the idler pulley 38 and the blocks 46. Each cam element consists of a track cam 18 (Fig. 4) having a central raised lobe 80, a low entrance and a low exit 86.

After traversing the idler pulley 30 an erected sensing element is in position 6 (Figs. 2 and 4) in which its shank 54 is erect but rests on the pin 10 and leansin a rearward direction. The entrances=84 to the cam tracks 18 are at the level of'the cam follower with the sensing element in position e. As the moving belt 28 carries the sensing element between the two cam elements 14, 1B the opposite ends of the follower pin 10 ride into the entrance of the cam tracks. Furthermovement of the carrier belt will lift the cam follower and link, causing the latter to rotate in a counterclockwise direction as viewed in Fig. 4.- with respect to the block 55. It will be observed that since at this time the shank of thesensing elementis resting on the follower, upward movementof the follower causes the sensing element to-rotate with the link about the pivot 64. The lobe '80 is of such height that it will lift the link sufiicienly to oscillate the sensing element to a position f (Fig, 4) in which its centerof gravity 6. is forward of the axis ofpivotal movementof the sensing'element with respect to its associated link. When this position is reached the sensing element will fall into acondition of stable equilibriumin which its shank restsagainst the support 68. Thereafter the cam follower willmove down the descending part of the cam tracks: to restore-the link to its normal'horizontal position b lying flat on the steel belt. The sensing'element now moves betweenthe two rods 50 and is ready to-detect the presence of a broken or slack thread.

To make certain that the cam follower enters the-cam tracks, both cam elements are fashioned with upwardly inclined and rearwardly extending lips 88 which terminate at the upper edges of. the entrances 84 to the cam tracks. If, due to.- the presence of dirt or other foreign material on-the beltbeneath a link, the linkapproaches the cam elements in raised position, as shown for example by position 9 in Fig; 4, the cam follower T0: will engage the undersurfaces of the lipsBB andhe forced into the entrances 84' of the cam tracks. If a cam follower does not ride through the cam tracks a-sensing element might approach theen-itrance-to the rods Eifwhile still in the 6 position and thereby jam and distort against the rods.

To facilitate contact of the head? 56 of the sensing element with both rods Eil'at the. time that the sensing element drops on the rods, the edges of the sensing element which engagesaid rods are sloped down towards the distal end. of the shank 54 as already mentioned. Thiszarrangement enables the head to center itselfbetween the rods and thus ensures engagement with both rods. It is for such purpose that the: pivotal mounting of the sensing element .on the-link. is so constructed as to permit sidewise play thereof.

When a sensingelement drops into engagement with the two rods, the gravitational force which holds the head of the element against the rodsgis extremely light. Hence it is desirable to. ensure that the contact surfacesof the rods are kept clean.

Accordingly a wiper 90' is mountedon the belt in line with the sensing elements. The wiper is secured to ablock 92 that is rigidly connected to the belt, the wiper being attached to said block by a pin 94 which permits rotation" of the wiper about a horizontal axis. Like the-sensingv elements, the pivotal mounting of 'the wiper permits some side play and rocking to ensure centering of thewiper between the rods. The wiper is com,- posed of rubber or a synthetic elastomeric substance and includes a shank 96 with a head98 whose sides slope upwardly and outward from the distal end of the shank. The sides of the head ride on the-upper sides of :the rods 50 and by con-.- stant scraping action keep the contact surfacesof the rods clean.

The width of the wiper head exceeds therspace between the rods 50 but is less thanthespace between the cam tracks 18 so that it is not lifted thereby. When the wiper approaches the blocks 46 itshead is slightly below the level'ofthe rods being supported in such position by a stepxlllil on the block-92. In order to raise the wiper head one of the blocks 46 is formed'with a ramp, 1. e. a cam surface I02, along which the wiper rides and is lifted to the level of'the rods.

It thus will be seen that there is provided a device which achieves all the objects of the invention and is well adapted to meet the conditions of practical use.

As: various possible embodiments might be 7 made of the above invention, and as various changes might be made in the embodiment above set forth, it is to be understood that all matter herein described, or shown in the accompanying drawings, is to be interpreted as illustrative and not in a limiting sense.

Having thus described the invention, there is claimed as new and desired to be secured by Letters Patent:

1. A multi-fllament-responsive thread break detector comprising an extremely light sensing element, a carrier, means to mount said carrier for movement transversely beneath the path of a largenumber of threads, means to mount said element on said carrier for movement with respect to said carrier between an unactuated position and an actuated position and in a direction having a substantial component parallel to the direction of movement of said carrier, a pair of elongated members disposed on opposite sides of the path of travel of said element slightly below the distal end thereof, the unactuated position of said element leading the actuated position thereof and said element normally being disposed in unactuated position whereby when a slack thread falls in the path of travel of said element it will impede motion of said element and cause said element to shift from unactuated to actuated position, and electric circuit closing means rendered effective upon movement of said sensing element to actuated position.

2. A multifilament-responsive thread break detector comprising an extremely light sensing element, a carrier, means to mount said carrier for movement transversely beneath the path of a large number of threads, means to mount said element on said carrier for movement with respect to said carrier between a high unactuated position and a low actuated position and in a direction of movement of said carrier, the unactuated position of said element leading the actuated position thereof and said element normally being disposed in unactuated position whereby when a slack thread falls in the path of travel of said element it will impede motion of said element and cause said element to shift from unactuated to actuated position, and a pair of electrically conductive rods lying on opposite sides of the path of travel of said element and disposed to be engaged by said element when the same is in its low actuated position whereby to constitute electric circuit closing means which is rendered effective upon movement of said sensing element to actuated position.

3. A multi-fllament-responsive thread break detector comprising an endless flexible belt, a pair of horizontally journalled pulleys supporting said belt with an upper reach extending transversely beneath the path of a large number of threads and a lower reach, an aligned set of extremely light sensing elements, means to mount each element on said belt for pivotal movement about a horizontal axis between a high unactuated position and a low actuated position, each said pivotal axis being transverse to the direction of movement of said belt, the unactuated position of each element leading the actuated position thereof and each element normally being disposed in unactuated position on the upper reach whereby when a slack thread falls in the path of travel of any element it will impede motion of said element and cause said element to shift from unactuated to actuated position, and a pair of electrically conductive rods lying on opposite sides of the path of travel of said elements on the tive upon movement of any sensing element to actuated position.

4. A multi-fllament-responsive thread break detector comprising an endless flexible belt, a pair of horizontally journalled pulleys supporting said belt with an upper reach extending transversely beneath the path of a large number of threads and a lower reach, an aligned set of extremely light sensing elements, means to mount each element on said belt for pivotal movement about a horizontal axis between a high unactuated position and a low actuated position, each said pivotal axis being transverse to the direction of movement of said belt, the unactuated position of each element leading the actuated position thereof and each element normally being disposed in unactuated position on the upper reach whereby when a slack thread falls in the path of travel of any element it will impede motion of said element and cause said element to shift from unactuated to actuated position, a pair of electrically conductive rods lying on opposite sides of the path of travel of said elements on the upper reach, said rods being disposed to be contacted by any element when the same falls into actuated position whereby to constitute an electric circuit closing means which is rendered eifective upon movement of any sensing element to actuated position, said elements falling to actuated position as they move around a pulley from the lower to the upper reach, and means to shift each element from actuated to unactuated position between said pulley and the rods.

5. A multi-filament-responsive thread break detector comprising an endless flexible belt, a pair of horizontally journalled pulleys supporting said belt with an upper reach extending transversely beneath the path of a large number of threads and a lower reach, an aligned set of extremely light sensing elements, means to mount each element on said belt for pivotal movement about a horizontal axis between a high unactuated position and a low actuated position, each said pivotal axis being transverse to the direction of movement of said belt, the unactuated position of each element leading the actuated position thereof and each element normally being disposed in unactuated position on the upper reach whereby when a slack thread falls in the path of travel of any element it will impede motion of said element and cause said element to shift from unactuated to actuated position, a pair of electrically conductive rods lying on opposite sides of the path of travel of said elements on the upper reach, said rods being disposed to be contacted by any element when the same falls into actuated position whereby to constitute an electric circuit closing means which is rendered effective upon movement of any sensing element to actuated position, said elements falling to actuated position as they move around a pulley from the lower to the upper reach, and cam and follower means to shift each element from actuated to unactuated position between said pulley and the rods.

6. A multi-filament-responsive thread break detector comprising an endless flexible belt, a pair of horizontally journalled pulleys supporting said belt with an upper reach extending transversely beneath the path of a large number of threads and a lower reach, an aligned set of extremely light sensing elements, means to mount each element on said belt for loose pivotal movement about a horizontal axis between a high unactuated position and a low actuated position, each said pivotal axis being transverse to the direction of movement of said belt, the unactuated position of each element leading the actuated position thereof and each element normally being disposed in unactuated position on the upper reach whereby when a slack thread falls in the path of travel of any element it will impede motion of said element and cause said element to shift from unactuated to actuated position, and a pair of electrically conductive rods lying on opposite sides of the path of travel of said elements on the upper reach, said rods being disposed to be contacted by any element when the same falls into actuated position whereby to constitute an electric circuit closing means which is rendered effective upon movement of any sensing element to actuated position.

7-. A multi-filament-responsive thread break detector comprising an endless flexible belt, a pair of horizontally journalled pulleys supporting said belt to provide an upper reach extending transversely beneath the path of a large number of threads and a lower reach, power means to turn one of said pulleys, an aligned set of extremely light sensing elements, each of said ele ments including a shank having a head at its distal end and means to pivotally secure the proximal end of said shank to said belt for movement about a horizontal axis transverse in the direction of movement of the belt, a set or supports carried by the belt, each support being associated with a difierent sensing element and arranged to have the shank of the element rest thereon when the shank is on the upper reach and is inclined in the direction of the movement of the belt, the center of gravity of each sensing element in such position being forward of its associated horizontal axis, a pair of electrically conductive rods lying on opposite sides of the path of travel of said elements, the transverse dimension or the head of each element exceeding the space between said rods whereby when a slack thread falls across the rods it will impede motion of an element and cause said element to be swung about its axis of povital movement and fall upon said rods, said rods and element constient link, means to pivotally connect each of said links to its associated block for movement rela tive thereto about a horizontal axis transverse to the direction of movement of the belt, a support carried by each link, a transversely extending follower carried by each link, an extremely light sensing element pivotally connected to each link for rotation relative thereto about a horizontal axis transverse to the direction of movement of the belt, each sensing element including a shank and a head, said shank being pivotal between a position in which it rests on the support and a position in which it rests on the cam follower, said shank in its first named position on the upper reach leaning in the direction or" movement of the belt, and in its second-named position leaning in a direction opposite to the movement of the belt, the center of gravity of each sensing element in its first named position on the upper reach being forward of the horizontal pivotal axis of the sensing element, said links and sensing elements dangling from the belt when on the lower reach, said link resting on the belt and said sensing element being in its secondnamed position when the link and sensing ele ment travel around a pulley from the lower to the upper reach of the belt, a cam engageable by the cam follower for swinging each link away from the belt shortly after it travels around said pulley and thereby advancing the center of gravity of the associated sensing element forwardly of the horizontal pivotal axis of said element, said cam including a portion for returning said link to a position resting on the belt with the sensing element in its first-named position, and a pair of electrically conductive rods disposed on opposite sides of the path of travel of said sensing elements on the upper reach of the belt whereby when a slack thread falls on said rods in the path of travel of any element on the upper reach of the belt it will impede movement of said element and cause said element to swing about its horizontal pivotal axis toward the second position and until it engages said rods, said rods and sensing element constituting an electric circuit closing means.

10. A multi-filamcnt-responsive thread break detector as set forth in claim 9 wherein the cam includes a portion engaging the cam follower on a link and forcing the same toward the belt, if the same is in raised position prior to engagement of the cam follower with the lifting portion of the cam.

CLYDE B. HAYES.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,970,264 Welch et a1. Aug. 14, 1934 FOREIGN PATENTS Number Country Date 570,639 Great Britain July 16, 1945

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