US3517497A - Thread guard with thread brake - Google Patents

Description

June 30, 1970 H. RETTENMU ND 3,517,497

THREAD GUARD WITH THREAD BRAKE Filed June 24, 1968 a 2 Sheets-Sheet 1 Hahs Reffenmund mvzu'ron.

' ATTORNEY June 30, 1970 H. RETTENMUND 3,517,497

THREAD GUARD WITH THREAD BRAKE WWI INVENTO R.

:Kfl ATTORNEY 155 Hans Reffenmuncl 3,517,497 THREAD GUARD WITH THREAD BRAKE Hans Rettenmund, Horn, Thurgau, Switzerland, assignor to Carl Hamel, Spinnund Zwirnereimaschinen AG, Arbon, Switzerland, a corporation of Switzerland Filed June 24, 1968, Ser. No. 739,268 Claims priority, applicfitign 1Gzgrmany, June 27, 1967, 3

Int. (:1. D1h 13/16 US. C]. 57-81 Claims ABSTRACT OF THE DISCLOSURE My present invention relates to textile machinery of the general type described in commonly owned US. Pat. Nos. 2,972,856 and 3,388,544 in the name of Edmund Hamel, i.e. a plant with one or more supply reels from which threads are continuously drawn to a bobbinbuilding mechanism or equivalent take-up means while being monitored by associated thread guards designed to arrest the take-up means in the event of a thread rupture.

In a typical system of this type, at least two threads drawn from respective reels are twisted together into a yarn which is then wound on a bobbin core carried by a spindle; usually, a multiplicity of such spindles are disposed side by side on a common support which may be vertically reciprocated with reference to a set of traveler rings, or vice versa, the travelers on these rings forming part of the guide means required to wind the yarn around the cores. With a bank of closely spaced spindles, the associated supply reels are also mounted with little relative separation; thus, the loose end of a broken thread can become entangled in one of the threads of an adjoining twisting station even though the corresponding spindle is stopped. Apart from entailing the danger of initiating a chain of thread breaks along adjoining stations, such entrainment of a thread from a neighboring supply reel may continue unnoticed for a while and will then result in a yarn of excessive thickness having more than the specified number of constituent threads.

The general object of my present invention is to provide means for positively preventing such entanglement or entrainment of threads after a rupture.

This object is realized, pursuant to my present invention, by the provision of one or more brakes for arresting the supply reel or reels of a twisting station or similar thread-handling equipment upon the sensing of a rupture by an associated thread guard.

Where two or more supply reels feed a common take up spindle, these reels may be jointly arrested by a single brake assembly responsive to the rupture of any of the associated threads; advantageously, the brake assembly includes individual brakeshoes for the several reels. Since, however, the supply reels must not be stopped before the arresting of the spindle drive if over-stressing of as yet unbroken threads is to be avoided, I prefer in such a case to provide means for delaying the operation of the brake assembly beyond the actuation of the spindle drive. The delay may be realized in a variety of ways, e.g. mechanically or electronically; a mechanical delay device according to my invention may include a lost-motion United States Patent 0 "ice assembly connecting an actuating element with a swingable arm carrying the brakeshoe.

The above and other features of my invention will become more fully apparent from the following detailed description, reference being made to the accompanying drawing in which:

FIG. 1 is a somewhat diagrammatical illustration of a bobbin-building mechanism, of the general type disclosed in the aforementioned prior Pat. No. 3,388,- 544, equipped with a multiple-thread monitor controlling a pair of reel brakes according to my invention;

FIG. 2 is a side view of a dual reel brake according to the invention, replacing the individual brakes shown in FIG. 1; and

FIG. 3 is a top view of the brake assembly of FIG. 2, showing additional elements associated therewith.

As shown in FIG. 1, two separate reels 2, 2 deliver a pair of threads 1, 1 to respective feeding units 4, 5 and 4', 5 which individually advance these threads, possibly at different rates, to a twisting station in which the threads are combined into a yarn 8 to be wound into a bobbin 11. Thread 1', after passing around a deflecting bar 7, joins the thread 1 in an eyelet 6 from which the yarn 8 advances to a traveler ring 10 which circles the axis of bobbin 11 on an annular track 9 reciprocating in the direction of the bobbin axis (arrow A) as is well known per se. The bobbin 11 has a core 21 mounted on a spindle 22 which is driven, via a transmission 23, from a motor 24 whose power supply has been diagrammatically indicated as a generator 25 in series with a pair of contacts 16. It will be understood that, in accordance with general practice, a multiplicity of bobbins 11 are built simultaneously on a bank of spindles 22 which are usually so closely spaced that, in the event of a rupture, a loose thread would be come entangled with the yarn of a neighboring bobbin if the affected spindle were not promptly arrested.

In accordance with the disclosure of Pat. No. 3,388,544 there is provided, for each of the threads 1, and 1', an individual thread guard shown to comprise a bell-crank lever 3, 3' pivoted at a respective fixed fulcrum 2 6, 26'. By its own weight, and/ or by the action of a weak spring 27,27, each lever 3, 3 is biased for svn'nging in a counterclockvw'se direction as indicated by arrows B, B. Such a swing, however, is normally prevented by the tension of the associated thread 1 or 1 which passes through a loop on the free end of the nearly horizontal bell-crank arm, thus holding the vertical arm against a respective stop 17, 17'. The vertical arms of levers 3 and 3' are disposed next to respective abutments 15 and 15' on a horizontal bar 14 which is suspended from links 28, 28'; these links are articulated to the bar 14 and have fixed fulcra at 29, 29 whose spacing substantially corresponds to the length of the bar so that a parallelogrammatic linkage is fonmed. Links 2 8, 28' are provided with integral extensions 12, 12' disposed unsymmetrically with reference to fulcra 29, 29 so as to tend to maintain the link 28 in contact with an abutment 30. Extensions 12 and 12' terminate in cams 13, 13' which, upon a counterclockwise swing thereof as indicated by arrows C, C, lift the respective counterrollers 5, 5' of the associated feeding unit from the corresponding driven rollers 4 and 4 to halt the drawing of further lengths of thread 1, 1 from reels 2, 2. Bar '14, in its illustrated normal position in which cams 13 and 13' are withdrawn from rollers 5 and 5', keeps closed the contacts 16 in the energizing circuit of motor 24'; naturally, this energizing circuit may include other switches, not shown, for starting and stopping the motor in the closed state of these contacts.

As long as the threads 1 and 1 are intact, elements 12-14 occupy their illustrated position and the system operates in the normal manner to build the bobbin 11. If, however, thread 1 is ruptured, lever 3 swings in the direction of arrow B and bears upon the abutment to displace the bar 14 to the right, as indicated by arrow D, whereby contacts 26 are opened and motor 24 stops. At the same time the arms 13 and 13 lift up the counterrollers 5 and 5 which, in the embodiment illustrated, normally rest under their own weight on the associated driven rollers 4 and 4. Both feeding units 4, 5 and 4', 5' are thereby deactivated even though rollers 4 and 4' may continue to rotate.

In an analogous manner, a rupture of thread 1 will cause the lever 3 to swing in the direction of arrow B to stop the motor 24 and to lift the two counterrollers 5 and 5'. Whereas, however, lever 3 engages the thread 1 ahead of feeder 4, 5 so as to respond instantly to any break in the thread between the reel 2 and the feeder, lever 3 is in contact with thread 1' at a downstream location from feeder 4, 5, between the latter and deflecting bar 7, whereby a break in thread 1' will become eifective as soon as it clears the rollers 4', 5; at the same time, any rupture in the yarn 8 will slacken the thread 1' so that thread guard 3 will react in the same manner as if this thread itself had been broken.

In accordance with an important feature of my present invention, I provide a set of contacts 31 closable by the bar 16 in its off-normal position, these contacts being part of an operating circuit for a relay 32 which also includes a source of current 33 (here shown as a battery), a capacitor 34 and a choke 35. Reactances 34 and 35 constitute, together with the resistance of relay 32, an aperiodic network which energizes the relay 32 after a predetermined interval designed to allow the spindle 2.2 to come to a halt upon de-energization of motor 24. Relay 32, in attracting its armature, energizes two solenoids 36, 36' connected in parallel; each of these solenoids actuates a respective brake 37, 37 in the form of an arm swingable about a fulcrum 38 or 38' against the force of a restoring spring 39, 39, thereby urging a respective brakeshoe 40, 40 into contact with the periphery of the associated reel 2 or 2'.

In FIG. 1, for the sake of clarity, the reels 2, 2' and their associated brakes 37, 37 have been shown disposed at widely separated locations; in practice, as illustrated in FIGS. 2 and 3, these reels may be closely juxtaposed along with their associated brakes whose construction may be generally similar to that described hereinafter.

In FIGS. 2 and 3 I have shown a pair of reels 116, 116" delivering threads 118 and 118' via eyelets 120 and 120' to a take-up mechanism which may be similar to that illustrated in the aforementioned Pat. No. 2,972,856, comprising a pair of transport rollers (not shown) embraced by the yarn 119 which is formed from the threads 118, 118' beyond upon their convergence at a deflecting roller 121. Reels 116 and 116' have cores 114, 114' journaled on respective pins 112, 112' projecting from a common support 110, the latter forming part of a machine frame not further illustrated. Also mounted on this frame is a bear ing 134 for a shaft 132 disposed rearwardly of the two reels, i.e. on the side remote from the vertices of the cone angles of their frustoconical peripheries. Journaled on shaft 132 for swinging movement about its axis are two brake arms 124 and 124' terminating in respective brakeshoes 126 and 126', the latter having contact surfaces provided with spikes 128 (as shown for the shoe 126 in FIG. 3) for positive engagement with the interstices of the filamentary reel surfaces. A lever with two arms 136, 138 is rigid with shaft 132 and has its arm linked with an extension 130 of arm 124 by a contractile spring 142 tending to maintain this extension in contact with an abutment 140 on arm 136. The free end of arm 138 is coupled to a lever 143 which has a fixed fulcrum 144 and is rigid with an arm 146, the free end of the latter arm being linked via a rod 148 with the free end of a lever 150 having a fixed fulcrum 151. An extension 152 of lever 150 is engaged by the yarn 119; with a spring 153 biasing the lever 143 in a counterclockwise sense as viewed in FIG. 3, the linkage 136, 13-8, 143, 146, 148, 150*, 152 maintains its normal position (illustrated in full lines) only as long as the yarn 119 is intact. If the yarn breaks, this linkage is urged by the spring 153 toward an alternate position (dot-dash lines) in which the spring 142 is stressed to swing the brake arm 124 toward the reel 116; a weight 158, form ing a massive extension of arm 124, imparts sufiicient inertia to this brake arm to retard its swing until the associated spindle drive has come to a halt.

The second brake arm 124' is provided with a similar weight, not shown, and has an extension connected through a spring 142' to an arm 136' rigid with shaft 132. In this mamler the brake shoes 126, 126 move independently into engagement with the respective reel peripheries.

It will be apparent that the swing of brake arms 124, 124' increases progressively with the shrinking of the reels 116, 116' as the threads 118, 118' are unwound therefrom. Since, however, the tendency of these reels to rotate by their own inertia decreases with the reduction of their diameters, the braking action need not be so effective in the latter part of the unwinding operation and, in fact, may not be required at all in the terminal stages thereof.

The arrangement illustrated in FIGS. 2 and 3 may, of course, be expanded to encompass more than two reels and could also be modified along the lines of FIG. 1 with substitution of an electrical actuator for the mechanical brake release shown in FIG. 3. Moreover, each reel brake may be individually actuatable by its own thread guard, with or without joint actuation in the event of simultaneous rupture of both threads in the twisted yarn; for this purpose, the threads 118, 118 may pass next to each other along the path 119 and may be separately monitored by respective feelers 152 before being intertwined at a point further downstream.

These and other variants, readily apparent to persons skilled in the art, are intended to be embraced within the spirit and scope of my invention except as otherwise limited in the appended claims.

I claim:

1. In a plant comprising a support for a rotatable thread-supplying reel, feed means for continuously drawing a thread from said reel and monitoring means positioned for engagement with said thread to sense a rupture thereof, the combination therewith of brake means positioned adjacent said support and coupled with said monitoring means for arresting said reel in response to such rupture, said brake means comprising an arm swingable in a generally axial plane of said reel and provided with a thread-engaging shoe positioned to bear upon the reel periphery.

2. The combination defined in claim 1 wherein said shoe is provided with a point-studded surface engageable with said reel periphery.

3. In a plant comprising a support for a rotatable thread-supplying reel, feed means for continuously drawing a thread from said reel and monitoring means positioned for engagement with said thread to sense a rupture thereof, the combination therewith of brake means positioned adjacent said support and coupled with said monitoring means for arresting said reel in response to such rupture, take-up means for said thread including a rotatable spindle, said feed means including drive means for rotating said spindle, said monitoring means being coupled with said drive means for deactivating same upon the occurrence of a rupture; and delay means interposed between said monitoring means and said brake means for retarding actuation of the latter beyond deactivation of said drive means.

4. The combination defined in claim 3 wherein said delay means comprises an electric delay network.

5. The combination defined in claim 3 wherein said delay means comprises a mechanical lost-motion assembly.

6. The combination defined in claim 5 wherein said lost-motion assembly comprises a swingable arm, an actuating element connected with said monitoring means for displacement thereby, and a resilient linkage between said element and said arm, said brake means including a shoe carried on said arm.

7. The combination defined in claim 6 wherein said element is a lever pivoted on the swing axis of said arm and provided with spacing means normally bearing upon said arm.

8. The combination defined in claim 6 wherein said linkage comprises a spring anchored to an end of said arm remote from said shoe, said arm being provided with a massive extension in the vicinity of said shoe.

9. The combination defined in claim 3, further including a support for a second rotatable thread-supplying reel adjacent the first-mentioned support, said take-up means being operable to wind the threads of both reels jointly around said spindle, said monitoring means being responsive to rupture of either thread, said brake means being eflfective to arrest both said reels simultaneously.

10. The combination defined in claim 4 wherein said brake means comprises an arm swingable in a generally axial plane of said reel and provided with a shoe positioned to bear upon the reel periphery.

References Cited UNITED STATES PATENTS 303,210 8/1884 Boyd 5782 2,599,256 6/1952 Hartley et a1. 5784 2,786,324 3/1957 Keith et al 5780 XR 2,840,979 7/1958 Harmon 5780 XR 2,930,182 3/1960 Lenk 5784 3,251,562 5/1966 Petersen 5781 XR 3,262,180 7/1966 Findlow 5781 XR 3,372,848 3/ 1968 MacDonald et al. 3,388,544 6/1968 Hamel 57--81 DONALD E. WATKINS, Primary Examiner US. Cl. X.R.

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