US2707977A - Loom stop motion - Google Patents

Description

y 10, 1955 K. E. SANDERSON 2,707,977

LOOM STOP MOTION Filed Feb. 11, 1955 2 Sheets-Sheet 1 19 79/17 I/QI'O LINE 15 zIg z AC. 12 V UNGROUNDED.

@ 5 9 KENNETH i ifi g ow A TTORNEY y 19, 1955 K. E. SANDERSON 7,977

LOOM STOP MOTION 2 Sheets-Sheet 2 Filed Feb. 11, 1955 k KQZ%M% A TTORNEY United States Patent 0 LOOM STOP MOTIDN Kenneth E. Sanderson, Hopedale, Mass., assignor to Draper Corporation, Hopedale, Mass., a corporation of Maine Application February 11, 1953, Serial No. 336,280

10 Claims. (Cl. 139-336) This invention pertains to a stop motion for looms, and more particularly, to an electro-mechanical type stop motion effective upon failure of power to the loom and upon failure of a weaving thread therein.

It is a general object of the invention to devise a stop motion for the purposes stated which shall be simple, effective and certain in its operation.

It is a more specific object of the invention to devise a simple stop motion circuit which shall act as a power failure loom knock-off means and which shall function with a closed circuit at low voltage and with low current consumption.

It is a further object to devise a stop motion circuit in which sparking at the drop wires shall be greatly reduced and further, which shall have a slow or delayed action such that reasonable swaying of the wires will not result in stopping the loom.

It is a further object of the invention to devise a stop motion circuit in which the resistance through which current to the various branches of the circuit is fed also serves as an indicator.

' A further obiect is that of devising a stop motion which, once having given a definite signal for stopping the loom, cannot be aflected by bouncing of the stop motion drop wires so that the signal would be at least temporarily nullified.

Other objects of the invention will become apparent from the following more detailed disclosure.

In the operation of looms for weaving stop motions are provided for signalling a knock-off of the loom upon failure of a weaving thread, either filling or a warp thread. It has further been desired and suggested (U. S. Patent 2,300,098) that provision be made for knocking 01f the loom upon failure of power thereto. While the loom would, of course, stop if power to it failed, it is desired that the knock-off means function so that when power returns, the loom may not start under improper conditions.'

It is desired that these stopping means be combined in a simple, effective circuit. Electric stop motions are also beset by certain objectionable characteristics, notably a tendency to sparking at the drop wires as they complete their circuit and then temporarily lose contact with their electrodes. The vibration of a loom is considerable and causes a swaying and bouncing of the drop wires so that in some instances false indication or signal is given thereby stopping the loom even though no real reason for the stop is present. Again, when a signal has been properly given, the bouncing of the wires may negative it for a brief interval causing the stop motion to make another try before knock-off is effected.

According to the invention these and other diificulties are overcome by use of a circuit which is primarily resistive in nature rather than inductive. The various parts of the circuit incidental to stopping upon definite cause are branched to receive current selectively through a resistance of low value and having a substantial thermal lag. Normally current flows through said resistance 2,707,977 Patented May 10, 1955 "ice and through a closed circuit in that branch effective for stopping upon power failure to energize an electro-magnet for retaining a detent or the like out of the path of a moving actuator. The resistance is of such low value as to pass current required to energize the magnet and when a circuit is completed through the other branch in which a stop motion thread condition detector is maintained, the resistance passes the current which is diverted from the first branch, but since the total resistance is less, heats the feed line resistance which has a substantial thermal lag, thereby causing a delay in the functioning of the circuit as it signals a knock-off to stop the loom. If an incandescent lamp of suitable characteristics is used as a resistance, it may also serve as a visual signal. Such a lamp must have very low resistance when cold and thus serves to pass the small current needed to energize the holding magnet; however, it does not glow without more current. When the current is grounded or the circuit otherwise completed at the stop motion detector, the current tends to rise rapidly, but is held down momentarily as the resistance of the lamp filament increases rapidly upon becoming heated. The action of the circuit is thus rendered sufiiciently sluggish so that the swaying or other unintended contacts made by drop wires has no apparent effect.

When current is passed through the stop motion branch of the circuit, the voltage drops at the electromagnet until it can no longer hold the detent. The latter then moves to position to be picked up by the moving actuator whereupon the loom will be knocked off.

The invention will be described in greater detail by reference to the accompanying figures of drawing, wherem:

Fig. l is an end elevation of a loom to which the in vention has been applied.

Fig. 2 is an electrical diagram showing in simple manner the circuit involved.

Fig. 3 is a vertical section through the moving actuator and detent portion of the mechanism.

Fig. 4 is an elevational view of part of the device shown in Fig. 3.

Fig. 5 is a View, partly in section, showing the detent resetting means.

Now referring to Fig. 1, part of a loom such as that described in full in U. S. Patent 2,604,123 has been illustrated and including a loomside 10, beam bearing 11, driving motor 12, side brackets 13 and 14 and filling inserting means supporting and actuating devices and enclosing casings generally indicated by numeral 15.

The motor 12 is controlled to be stopped and started by lever 16 connected through linkage to a hand lever 17 pivoted at 18 and having a knob 19 by which it is gripped. This lever has a second arm at 20 which is connected at one end 21 of link 22 connected at its other end to hell crank lever 23. This latter lever is pivoted on a fixed stud 24 and its other arm is connected to a second link 25. Link 25, in turn, attaches to a second bell crank 26 the motion of which is conveyed to lever 16 through cross link 27. Movement of the starter lever 17 to the full line position, Fig. 1, sets the loom in motion assuming the power has been turned on for motor 12. Preferably that motor is of the type having an internally carried clutch and brake and the latter is controlled simultaneously with the former. Movement of the linkage to the dotted line position disengages the clutch and applies the brake, that operation being re ferred to as knocking off the loom.

A moving actuator may be employed as a part of any convenient cyclically controlled element on the loom and here is in the form of a projection or tooth 2'8 attached to disk members 29 on cam shaft 30. These carry an eccentric pin 31 which causes pitrnan 32 to actuate the filling inserters in a manner disclosed in the patent above identified.

Now referring to Figs. 3 and 4 as well as Fig. 1, disk members 29 include a central hub 33 keyed by key 34 to shaft 3%), an inner, dished plate 35 in a notch in which tooth 28 is held and a ring 36. These three members are bolted together by bolts 37 and the eccentric pin 31. Shaft 36 is borne in hearings in the loomsides, one such being illustrated at 38.

A detent SS is pivoted at 4% in the forked end of a depending arm 41 angularly bent at its upper end to continue in a horizontally disposed extension 42 pivoted at ,43. The latter is a part of a boss cast or otherwise formed as a part of casing 44 attached to loomside It). A spring 45 between a cupped projection 46 and the top surface of the casing normally maintains the arm 41 as in Fig. 4. A coil spring 47, Figs. 3 and 5, engages a collar 48 on pivot 40 and also the forked end of arm 41, and is under tension so that the detent 39 drops to the position of Fig. 4 except at such times as it is held in elevated position by electro-rnagnet. The detent is fixed on its pivot 46 to move with it.

Downward movement of the detent is stopped by screw 49 threaded through a transverse member 50 in arm 41.

The collar 48 has a pin 51 passing through it and the pivot 46 and in addition to holding the collar in place, the pin extends downwardly to be engaged at times tfy a spring clip 52 carried by a bracket 53 clamped to rod 25 by a set screw or by any other satisfactory means.

This bracket is in the form of a pair of spaced, parallel cylinders connected by a web and, as shown, one said cylinder serves as a means to mount it on the rod 25 while the other is bored to receive a plunger 54 which is spring pressed to a position in which it projects slightly from the bracket. Spring 55 may be compressed to relieve shock and to permit operation with less accurate adjustment of parts.

An electro-magnet 56 having a core 57 and windings 58 is fixed in casing 44 so that the end of the core is positioned to align with the free end of detent 39. An air gap is maintained by a brass plate 59 of .005.0l0" in thickness or by any other suitable means. The magnet is a part of a circuit later to be described, but sufiice it to say at this point that the circuit is closed and the magnet is essentially a holding magnet and will not pick up the detent once it has been released. It is for that purpose that clip 52 having a V-shaped end 60 is used. When the loom is knocked off, the clip moves to the left, Figs. 4 and 5, and gets on the side of pin 51 so that when the loom is started again, the pin will be pushed l to the right and will swing the detent from the position of Fig. 4 to one where the magnet will hold it out of the path of the moving actuator.

One circuit that may be utilized is shown in Fig. 2.

The circuit is essentially a direct current one; although it may be operated on alternating current, that is more difiicult and not as satisfactory. Since alternating current is used for the motor 12, the same source of power is availed of for the stop motion circuit and thus some form of rectification is required. Preferably, a full wave rectifier 61 of selenium type is fed from the 12 v. line and while the output at one side of the rectifier is grounded as at 62, the other is connected by feed line 63 to' binder post 64 to which are also connected two branch circuits.

The first of these branches 65 leads to coil 58 and ground 66.

The second 67 leads to one of the electrodes of a stop motion detector 68 the other electrode of which is grounded at 6?. These electrodes are supplemented by a series of so-called drop wires, not shown, since the same and the action of this type of electrically actuated stop motion detector are well known see U. S. Patent No. 2,200,148. Of course, upon release of a drop wire upon failure of a weaving thread, the detector circuit is grounded.

A resistance R of special characteristics is placed in series in feed line 63 so that current to either branch must pass through it. This resistance preferably takes the form of an incandescent lamp such as a 12-16 v. truck type headlight bulb. The life of these lamps is far beyond anything to which they may be subjected and their resistance is relatively low when their filament is cold. When caused to glow the resistance increases very rapidly and the present circuit takes advantage of these resistance characteristics. Normally a very small current in the order of about /2 amp. at 9 v. is sufficient to energize magnet coil 58 and hold the detent. That current passes lamp or resistance R without heating its filament appreciably.

When a thread fails and circuit through the stop motion detector is completed, current tends to be shorted to ground at that side and to decrease at the magnet side Here the resistance of the magnet coil is considerably greater in value than the resistance of the detector circuit. As a result the magnet ceases to hold and the detent drops into the pathway of the moving actuator. As the latter catches the detent 39 it swings it and arm 41 against spring 45 so the back of the detent or some other correspondingly moving part engages plunger 54 and pushes it and rod 25 to the left, Figs. 1 and 4, thus knocking off the loom.

It is at the thread failure stopping phase that the hot resistance characteristics of resistance R come into play. Since its resistance increases greatly as the filament begins to glow, there is a lag or delay in the completing of the detector circuit and also in deenergizing the coil 58. This can by'the selection of proper parameters within the circuit be fairly widely varied, but it is sufficient for all practical purposes if the lag is of a duration such that swaying of the drop wires and other unintended contacts which might complete the detector circuit are prevented from so doing. However, it is a fact that when once released, the detent may not be recovered by the magnet and thus a signal to stop, once completed, cannot be recalled as has been experienced heretofore when a released drop wire has temporarily been bounced from its electrodes or one of them.

Sparking at the drop wires is reduced first, since the normal 12 v. 3500 milliamp current at the detector is reduced to 9 v. at 850 milliamps. Further, the circuit is purely resistive instead of inductive and therefore the tendency and magnitude of sparking are greatly lessened.

While not so shown here, the lamp may be used as a visual signal since it becomes lighted only when the stop motion and loom knock-off have stopped the loom.

In the case of a power failure, current merely ceases to flow and the coil 58, failing to be energized, releases detent 39. The loom will then coast until the moving actuator catches detent 39 to perform their intended function. Thereafter, power may be returned to the circuit, but the loom must be started manually.

Reverting to Fig. 1, current is brought in to a starter box 70 of conventional type and then is fed to motor 12 by conductor 71, and to rectifier 61 through conductor 72. The rectifier and lamp or resistance are here housed in a box 73 from which branch feed lines 65 and 67 may be seen leading to magnet 56 and to the stop motion detector which is specifically a warp thread detector, but which, of course, might well function upon failure of a filling or any Weaving thread.

In fact, while only a single stop motion detector is herein shown as it is desired to simplify the showing two or more detector systems may become a part of the circuit. Of course, if the lamp is to become a signal as well, it must be placed in an appropriate position, e. g., on the arch or some more elevated, open part of the loom.

To review the operation briefly, assume the loom to be running and that power fails. The loom will, of course, start to coast to a stop and the deenergization of magnet 56 releases detent 39. The detent immediately drops and the loom continues to coast until tooth 28 picks up the detent and swings it and arm 41 so that through plunger 54 and link 25, the knock-off means is actuated.

If the failure of a weaving thread occurs, current normally flowing through resistance R which is not heated by the small current required for the coil 58 is shorted to ground through the stop motion detector 68. Rise in current value due to drop in resistance at branch 67 as compared to that in branch 65 starts to heat the resistance R which responds with added resistance so that a lag in deenergizing magnet 56 prevents unintended stopping. However, if actual thread failure is present the magnet does release the detent and stopping then occurs as before.

To start the loom, shipper lever 17 is moved manually to the full line position and the m will start if all faults have been remedied. The clip end 60 pushes on pin 51 and swings the detent to a position to be held by the magnet. Link moves farther in each direction than pin 51 so the clip is of spring material and V-shaped end 60 snaps by pin 51 at each movement of the link. If the loom is stopped manually the detent is tripped, but, of course, will be reset when the loom is started. If power has failed, movement of the shipper lever cannot reset the detent as the magnet is not energized. Likewise if a drop wire is down or other thread fault still evident, attempted resetting is immediately accompanied by stopping through the mechanism herein described as the detent cannot be held by the magnet so long as the circuit is through the detector rather than the magnet.

While it is conceivable that more than one projection 28 may be used as a moving actuator, that would make it inevitable that the loom would then stop at more than one position. Since it is desirable to stop a loom with the harnesses level and the filling inserting means out of the shed, it is preferred to use only one such element and thus to assure stopping at one definite position only. This does mean that if only one tooth 28 is employed, the loom must be one having a capability of coasting a full revolution at power failure.

By way of example, the incandescent lamp preferably used as a resistance in the feed line has a resistance of 1.2 ohms at 9 v. While a driving motor with integral clutch and brake is shown by way of illustration, that may be supplanted by the older type of drive wherein a motor drives to an external clutch and where an independent brake is used.

While one embodiment of the invention has been disclosed, it is to be understood that the inventive concept may be carried out in a number of ways. This invention is, therefore, not to be limited to the precise details described, but is intended to embrace all variations and modifications thereof falling within the spirit of the invention and the scope of the claims.

I claim:

1. In a loom the combination of an electrically operated power means, a knock-ofif system for said power means, a moving actuator and a detent movable to and from a position to be engaged by said moving actuator, and when so engaged, being further movable for causing said knock-off means to stop the loom, a circuit having two branches and a current feed line to said branches, a holding magnet for said detent in one branch and a stop motion detecting means in the other branch, and a resistance having a thermal lag in said current feed line.

2. In a loom the combination of an electrically operated power means, a knock-off system for said power means, a moving actuator and a detent movable to and from a position to be engaged by said moving actuator, and when so engaged, being further movable for causing said knock-off means to stop the loom, a circuit having two branches and a current feed line to said branches, an electro-magnet in one said branch for retaining said detent out of contact with said moving actuator, a stop motion detecting means in the other said branch effective upon failure of a weaving thread to initiate stopping of the loom, and means in said feed line for passing current to said electro-magnet and for reducing sparking and slowing the action of the stop motion detecting means which comprises a relatively low resistance having a substantial thermal lag.

3. In a loom the combination of an electrically operated power means, a knock-off system for said power means, a moving actuator and a detent movable to and from a position to be engaged by said moving actuator, and when so engaged, being further movable for causing said knock-01f means to stop the loom, a circuit having two branches and a current feed line to said branches, an electro-magnet in one said branch for retaining said detent out of contact with said moving actuator, a stop motion detecting means in the other said branch effective upon failure of a weaving thread to initiate stopping of the loom, and means in said feed line for passing current to said electro-magnet and for reducing sparking and slowing the action of the stop motion detecting means which comprises an incandescent lamp having a low resistance when its filament is relatively cool and a relatively high thermal lag.

4. In a loom the combination of an electrically operated power means, a knock-01f system for said power means, a moving actuator and a detent movable to and from a position to be engaged by said moving actuator, and when so engaged, being further movable for causing said knock-01f means to stop the loom, a circuit having two branches and a current feed line to said branches, an electro-magnet in one said branch for retaining said detent out of contact with said moving actuator, a stop motion detecting means in the other said branch effective upon failure of a weaving thread to initiate stopping of the loom, and means in said feed line for passing current to said electro-magnet and for reducing sparking and slowing the action of the stop motion detecting means which comprises an incandescent lamp having a low resistance when its filament is relatively cool and a relatively high thermal lag and means forming a part of said knock-off means for resetting said detent as the loom is started.

5. In a loom the combination of an electrically operated power means, a knock-off system for said power means, a moving actuator and a detent pivoted to an arm so mounted that when the detent is moved into the path of the moving actuator, it will be swung against a part of the said knock-0E means thereby to cause it to stop the loom, a circuit having two branches and a current feed line to said branches, and means forming a part of said branch circuits and feed line for signalling the stopping of the loom upon power failure to the loom or upon failure of a weaving thread, which includes a magnet in one branch for holding the detent out of the path of the moving actuator, a thread fault detector in the other branch operable to complete a circuit through said branch upon failure of a weaving thread and a resistance in said feed line, said resistance having a value such that it passes a low current to said magnet without becoming heated to a point to increase its resistance substantially and further having a substantial thermal lag so that when current is increased upon shorting the said thread fault detector to ground, the voltage drop at the magnet will be appreciably retarded.

6. In a loom the combination of an electrically operated power means, a knock-off system for said power means, a moving actuator and a detent pivoted to an arm so mounted that when the detent is moved into the path of the moving actuator, it will be swung against a part of the said knock-ofi means thereby to cause it to stop the loom, a circuit having two branches and a current feed line to said branches, and means forming a part of said branch circuits and feed line for signalling the stopping of the loom upon power failure to the loom or upon failure of a weaving thread, which includes a magnet in one branch for holding the detent out of the path of the moving actuator, a thread fault detector in the other branch operable to complete a circuit through said branch upon failure of a weaving thread and a resistance in said feed line, said resistance comprising an incandescent lamp having a low resistance when its filament is relatively cool and a relatively high thermal lag.

7. In a loom the combination of an electrically operated power means, a knock-off system for said power means, a moving actuator and a detent movable to and from a position to be engaged by said moving actuator, and when so engaged, being further movable for causing said knock-off means to stop the loom, a circuit having two branches and a current feed line to said branches, one said branch comprising a closed circuit having a detent holding magnet therein, the other said branch having therein a stop motion detector normally in open circuit, the resistance in said first branch being appreciably greater than that of the second so that when the circuit in the second branch is completed, current is diverted from the first to the second, and a low resistance of high thermal lag in said feed line to retard the change occurring upon such diversion of current.

8. In a loom the combination of an electrically operated power means, a knock-off system for said power means,

a moving actuator and a detent movable to and from a position to be engaged by said moving actuator, and when so engaged, being further movable for causing said knockoff means to stop the loom, a circuit having two branches and a current feed line to said branches, one said branch comprising a closed circuit having a detent holding magnet therein, the other said branch having therein a stop motion detector normally in open circuit, the resistance in said first branch being appreciably greater than that of the second so that when the circuit in the second branch is completed, current is diverted from the first to the second, and a low resistance of high thermal lag in said feed line to retard the change occurring upon such diversion of current and means including a spring clip movable with said knock-oft means for engagement with said detent for resetting it upon starting the loom.

9. In a loom stop motion circuit the combination of a source of direct current, branches one of which comprises a closed circuit and another of which is normally maintained open, an electro-magnet in said closed circuit and a thread fault detecting means in said open circuit, a feed line from said source of current and a resistance in said line and having a relatively high thermal lag.

10. In a loom stop motion circuit the combination of a source of direct current, branches one of which comprises a closed circuit and another of which is normally maintained open, an electro-magnet in said closed circuit and a thread fault detecting means in said open circuit, a feed line from said source of current and a resistance in said line which comprises an incandescent lamp of low resistance when cool and having a high thermal lag.

References Cited in the file of this patent UNITED STATES PATENTS

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