US2981295A - Stopping mechanism for loom - Google Patents

Description

A ril 25, 1961 F. w. PAUL ETAL 2, 8

STOPPING MECHANISM FOR LOOM Filed April 24, 1958 1 I i I i i u 1 INVENTORS 1 1 I, 12 g s FREDERICK W.PAUL

{ jr 5 VIOTORESEPAVICH If i zmwm ATTGRNEY STOPPING MECHANISM FOR LOOM Filed Apr. 24, 1953, Ser. No. 730,588

8 Claims. (Cl. 139--336) and Victor F. Sepavich, to Crompton & Knowles Mass, a corporation of Massa- This invention relates to improvements in stopping means for looms and it is the general object of the invention to simplify manual stopping in a manner to insure stopping at a selected point in the loom cycle.

Experienced weavers are able to stop a loom correctly but inexperienced weavers have difiiculty in stopping the loom at the correct time, especially if the loom is running at high speed. Stopping should not occur until after picking of the shuttle has been completed and stopping, or at least disconnection of the driving means, should occur either when the energy of the lay is at a minimum, as at back center, or at some other desired point in the cycle. With a rapidly-running loom an inexperienced person has difficulty in avoiding too early or too late stopping.

It is an important object of the present invention to provide control means whereby loom stopping can be initiated whenever the Weaver observes a condition which requires stopping, but wherein actual stopping will not take place until the correct time in the loom cycle. In

terry towel looms which do not ordinarily have a warp stop motion for the pile warp the weaver may notice a slack or broken thread which requires loom stoppage, and in box looms the thread from an idle shuttle to the selvage may become broken and the weaver, seeing these conditions, may desire to stop the loom to repair the broken thread. These are mentioned as only two of several conditions under which stopping is eifected by rates Patent the weaver instead of by automatically acting stopping devices.

It is a further object of the invention to provide the loom with electrodynamic clutch and brake means and control these means through parallel circuits one of which includes a pushbutton which the weaver can depress from normal to abnormal position at any time in the loom cycle and the other of which includes a loom operated timer switch set to elfect stoppage at the desired point in the loom cycle. With such an arrangement the weaver can depress the stopping button and open one of the branches of the parallel circuit but the loom will continue to run until the other branch is opened by the loom operated switch. Actual stopping is thus not determined by the time of pushing the button by the weaver but rather by the concurrent opening of the manually operated switch and the loom operated timer switch.

Under certain conditions it may be desirable to stop the loom when there is a minimum of energy in the lay, that is, when the lay is at or near its back center position. At this time only the rotating parts of the loom have energy. If stopping is effected when the lay is on back center the loom brake is required to absorb energy of the rotating parts only and while there may be some running of the loom after the brake is applied the lay will be running at a comparatively low speed as it starts forward from its momentary condition of rest at back center. Under other conditions it may be desirable before braking to allow the shuttle to get at least part-way into the shuttle box toward which it has been picked to prevent the forward momentum of the shuttle derived from the lay from causing the shuttle to box incorrectly or fly out of the shed. I

It is a further object of the invention to enable the weaver by pressing a button in a low voltage circuit to apply a momentary high voltage to the brake coil and at the same time apply a high voltage reverse current to the clutch coil in order to effect rapid declutching. In this way a quick release of the clutch is effected and a high braking force is momentarily available to stop the loom without danger to the weaver of a high voltage shock.

The high and low voltage currents are applied simul-' taneously to brake and, upon dissipation of the high voltage the low voltage continues to impress upon the brake without interruption or time delay to prevent movement of the going parts of the loom afterthey had been stopped.

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

Fig. 1 is a front elevation of a loom showing the invention applied thereto, a

Fig. 2 is a diagrammatic plan view looking in the direction of arrow 2, Fig. 1,

Fig. 3 is an enlarged view of the rotary switch containing box shown in Fig. 2 showing the rotary switches,

Fig. 4 is a section on line 4-4, Fig. 3, and

Fig. 5 is a diagrammatic view of the electric circuit used with the invention.

In the following description the electric features and circuits will 'first be described and this will be followed by sufiicient description of the loom to show how the electrical features can be applied thereto.

The driving clutch C and the loom brake B are both of the electromagnetic type and operate normally under low voltage direct current. In order to effect rapid release of the clutch and quick application of the braking force higher voltage direct current is made momentarily available in addition to the low voltage current, but only thev low voltage part of the circuit is controlled by the previously mentioned manually operated switch.

Referring to Fig. 5, the loom has a transformer T having two secondary windings 1 and 2 which provide low and high voltage respectively. The winding 1 is connected to a full wave rectifier 3 which supplies low voltage direct current to wires 4 and 5. The winding 2, which may provide a voltage for instance 10 times that of winding 1 is connected to condenser or capacitor feed wires 6 and 7.

Wire 7 is connected to a fuse 8 and then to a resistance 9 which is in parallel with a relay R4. The resistance is connected also to capacitors or electric condensers 10 and 11 which are connected together by wire 12. Wire 13 from condenser 10 leads to a one-way rectifier 14 which is connected to wire 6, while condenser 11 is con nected by Wire 15 to another but opposite one-way rectifier 16 also connected to wire 6. Bleeder resistances 17 and 18 are provided for the condensers 10 and 11 respectively to permit slow dissipation of their charges.

When the main switch for the loom is closed current will flow first through one and then the other of the condensers depending upon the polarity of the alternations and during flow of current into the condensers there will be a sufficient voltage drop across the resistance 9 to energize the relay R4. When the main switchof the motor is closed switches S1 and S4 connected to wire 4 will be open but immediately upon energization of relay R4 switch S4 will be closed as indicated by dotted line a.

Closure of switch S4 completes a circuit from wire 20 open switch 23 as indicated by dotted line n and shunt switch SS3 as indicated by dotted line b, thereby energizing relay R1 which as indicated by dotted line c closes normally open switch S1. When the capacitors 10 and 11 become charged the voltage across relay R4 will drop and relay R4 will become deenergized, and switch S4 will open. By this time switch S1 will be closed to connect wires 4 and 20 in a holding circuit for relay R1.

Energization of relay R1 causes it to open normally closed capacitor control switch S2 as indicated by dotted line d. Shunt switch SS3 provides a by-pass for rotary switch RS3 and manual switch MS and other switches not shown and will remain closed as long as relay R3 is energized. Relay R1 will then be supplied through normally closed switch MS, or through switch SS3. Energization of relay R1 causes closure of switch CS1 as indicated by dotted line e. Normally closed switch BS2 will keep the brake energized to hold the loom at rest. The loom is now ready to start. The operator then presses the starting switch S which establishes a circuit between wires 4 and 5 through wires 20 and 25 and relay R2. Closure on relay R2 effects closure of the holding switch SA in wire 26 which will maintain relay R2 energized by current passing through switch S1. At this time switch S4 is likely to be open, but the circuit for relay R2 is completed through switch S1 which is held closed-by relay R1. Energization of relay R2 acts as indicated by dotted line m to open normally closed switch 21, thus opening one of the paths for current to relay R3.

Up to this time switch BS2 has been in its normally closed position but energization of relay R2 opens switch BS2 through a connection indicated by line so that the brake is disconnected from the low voltage direct current source. Energization of relay R2 by way of a connection indicated by dotted line g closes switch CS2. Closure of the switches CS1 and CS2 connects wires 4 and 5 through the clutch C. The loom will now be running and when the lay reaches top center timer rotary switch RS1 will open momentarily, thus breaking the circuit for relay R3 which drops out and switch SS3 will open. Current for relay R1 can fiow through switch MS or rotary switch RS3.

It is to be understood that the loom will be equipped with other types of electric switches than those already described such for instance as for filling stop motion, warp stop with the usual signal light, and electric protection. Operation of any of these stop motions will bring about deenergization of relays R1 and R2 to stop the 100m at positions of the lay usually favorable for the type of stop. If, however, the weaver should notice some conditionin the loom which is not provided for by an automatically acting stop motion, such as a broken warp thread in a terry loom or a broken thread from an idle shuttle, the switch MS will be depressed at any time so that one of the parallel branches between wire 20 and relay R1 will be open. Then shortly thereafter the loom controlled rotary switch RS3 will open and since this condition will interrupt flow of current from wire 20 to relay R1 the latter will become deenergized, resulting in opening of switch S1 and opening of switch CS1 and closure of the normally closed switch S2.

Since switch S4 is already open relay R2 becomes deenergized which results in opening the switch CS2 and closure of switch BS2. Closure of the latter switch permits low voltage direct current to flow through the brake and opening of switches CS1 and CS2 disconnects the clutch from the low voltage direct current line. Closure of normally closed switch S2 due to deenergization of relay R1 permits discharge of the capacitor or condensers and 11 through brake B and clutch C in the following circuit: capacitor 11, wires 15, 30 and 31 through the brake in the same direction as the flow of low voltage current, wire 32 through the clutch in a direction of reverse of the flow of low voltage current, wires 33 and 34, switch 52, wire .1 apacitor 10 and wire 12 back to capacitor 11. The momentary flow of high voltage current through the clutch quickly demagnetizes it, and flow of similar current through the brake causes the latter to exert a high braking force on the loom.

It will be noted that the switch MS which the weaver closes is on the low voltage side of the circuit and that the high voltage which is discharged by the condensers incident to stopping of the loom is not able to reach the switch MS and for this reason a weaver runs no risk of electric shock when the condensers discharge. During operation of the loom, relay R1 is energized and provides a fail-safe circuit, i.e., failure of the relay and deenergization thereof for any reason whatsoever will effect stoppage of the loom as above described.

Fig. 1 shows a type of loom to which the invention can be applied but it is to be understood that the invention is not limited in its use to that type of loom. As shown in Fig. 1 the loom has a frame 40 supporting atop or crankshaft 41 which makes a rotation each beat of the loom, a bottom shaft 42 which makes a rotation every second heat of the loom, and a rocker shaft 43 supporting swords 44 which carries the lay beam 45. The latter swings backwardly and forwardly between back and front centers each beat of the loom in usual manner and in the present instance is provided with a gang of shuttle boxes G having in the present instance upper and lower cells 46 and 47 which can be shifted with respect to the lay so that either of these boxes can be in active position for actuation of a shuttle by picker stick 48. The opposite end of the lay is provided with a single shuttle box 49 from which the shuttles are picked by stick 50.

The loom is provided with a driving motor M provided with a pinion 51 which meshes with a gear 52 which runs freely on crankshaft 41. Secured to this gear 52 as at 53, see Fig. 2, is the electromagnetic clutch C already described which is close to a magnetic plate 54 secured to the top shaft 41. The brake B already described is held against rotation on the loom by a support 55. The brake runs close to the disc 54 but will ordinarily be deenergized when the loom is running so that it will offer no resistance to turning of the top shaft. A gear 56 is secured to the top shaft in usual manner and meshes with a gear 57 of twice the size secured to the bottom shaft 42.

The electrical equipment already described is largely housed in three boxes which are mounted on the righthand side of the loom as viewed in Fig. l. The manual and stopping switches are housed in a box 60 fixed to the breastbeam 61 of the loom frame and the timer switches RS1 and RS3 are located in a second box 62. The latter box supports a small shaft 63 which is connected by equal gearing 64 to the top shaft 41 so that the switches within the box 62 are rotated once for each beat of the loom.

These switches are shown in detail in Fig. 4 and since they are alike except for their electric connections only one of them will be described in detail, namely, switch RS3. This switch includes a circular plate 70 secured as by keying to shaft 63 and connected adjustably as by screws 71 to a cam disc 72 having a short high area 73 and a much longer low area 74. A contactor arm 75 pivoted at 76 to the box but insulated therefrom has a follower 77 which engages the cam and also is arranged to engage an electric contact 78 fixed with respect to and insulated from box 62. As the shaft 63 rotates the follower 77 will be on the low dwell 74 a greater part of the cycle of the loom operation and close contact between arm 75 and contact 78, these parts constituting the previously described'rotary timer switch RS3 and maintaining the latter normally closed except for a brief interval represented by the short high dwell 73. Since it may be desired to change the time of manual stopping of the loom the disc 70 is provided with arcuate slots 80 for the screws 71 to permit the cam to be adjusted angularly wit-hrespect to the shaft.

Th remainder of the electrical mechanism may be located in the third box 85 which is supported on the upper part of the loom structure as shown in Fig. 1.

From the foregoing it will be seen that the invention sets forth simple means by which an inexperienced weaver can open switch MS and initiate loom stoppage at any time and effect stoppage at the correct point in the loom cycle by holding it open until switch RS3 is opened by operation of the cam 72. It will further be seen that the high voltage electric discharge from the condensers 1i) and 11 does not in any way reach the low voltage part of the circuit in which the switch MS is located and for this reason there is no risk of electric shock to the weaver. It will also be seen that provision is made for adjusting the time of opening of switch RS3 so that the loom can be stopped either when the lay is in back center position and momentarily has no energy stored therein, or can be stopped at a later time, as already mentioned.

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:

1. In a loom provided with electromagnetic driving clutch means and electromagnetic brake means, two electric switches one or the other of which must be closed for continued loom operation, electric circuit means including both switches and said clutch and brake means eifective when the loom is runing to cause a low voltage direct current to flow in one direction through the clutch means and cause deenergization of the brake means but effective when both switches are open to disconnect the low voltage from the clutch means and impress thereon a reverse high voltage direct current to dissipate residual magnetism and also energize the brake means with high voltage direct current to stop the loom, one of said switches opening at a given time in each cycle of the loom and the other switch being normally closed, said other switch being openable by the weaver at any time in a cycle of the loom and if maintained open through said given time causing both switches to be open to effect loom stoppage.

2. The loom set forth in claim 1 wherein the other switch is in a low voltage part of the circuit means.

3. In a loom provided with electromagnetic brake means, two electric switches one or the other of which must be closed for continued loom operation, electric circuit means including both switches in parallel and said brake means effective when the loom is running to cause deenergization of the brake means but eliective when both switches are open to energize the brake means by impressing thereon a momentarily acting high voltage direct current superposed with a low voltage direct current to stop the loom quickly and effective upon discharge of said high current to continue without interruption or time delay to impress a low voltage direct current on the brake means to prevent movement of the loom after stoppage thereof, one of said switches opening at a given time in each cycle of the loom without impressing high voltage on the brake means provided the other switch is closed, said other switch being openable by the weaver at any time in a cycle of the loom and if maintained open through said given time causing both switches to be open to impress the high and the low voltages simultaneously on the brake means.

4. The loom set forth in claim 3 wherein said other switch can be opened manually without impressing either high or low voltage on the brake means, provided said one switch is not open.

5. The loom set forth in claim 3 wherein the high voltage source is capacitor means.

6. The loom set forth in claim 3 wherein the capacitor is kept charged during operation of the loom.

7. In a loom provided with electromagnetic brake means, two sources of direct current electric power, one of low voltage and the other of a momentarily acting higher voltage, two electric switches in parallel, electric circuit means connecting said brake means and switches, one of said switches opening at a given time in each cycle of the loom and the other switch being normally closed but manually openable at any time in any cycle of the loom, said other switch if opened prior to said given time in any cycle and maintained open until said given time in the cycle enabling said one switch when opening at said given time to cause the higher voltage source to act momentarily together with the lower voltage source to operate the brake means to promptly stop the loom, and other means enabling the low voltage source upon discharge of said high voltage source to continue without interruption to operate the brake to maintain the loom against movement.

8. In a loom, electric brake means for stopping the loom, electric circuit means for the brake, two switches in parallel in said circuit means, one or the other of which must be closed to prevent stopping of the loom by the brake means, one of said switches being controlled by loom operation and closed the greater part of each cycle of the loom but opening briefly at a given time in each cycle, and the other switch being normally closed but manually openable at any time in the cycle, said other switch it held open from any time in a cycle prior to said given time of the cycle through the following given time of the cycle creating a condition wherein both switches are open, whereupon the circuit means impresses a momentary high direct current voltage simultaneously with a low direct current voltage on the brake means to stop the loom promptly followed by dissipation of said high voltage and uninterrupted continual application of said low voltage to said brake means to keep the latter energized to prevent movement of the loom, the time of impressing the low voltage and the high voltage being determined by concurrent opening of said other and said one switch and not by the time of manual opening of the other switch.

References Cited in the file of this patent UNITED STATES PATENTS 2,600,667 Mason June 17, 1952 2,638,941 Hindle May 19, 1953 2,638,942 Hindle May 19, 1953 2,753,894 Lovshin et a1 July 10, 1956 2,781,794 Bordewieck et al. Feb. 19, 1957

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