US2466332A - Control for loom electronic systems - Google Patents

Description

April 5, 1949. I v. F. SEPAVICH ET AL 2,466,332 I CONTROL FOR LQQM ELECTRONIC SYSTEMS v Filed July 26, 1946 INVENTORS VICTOR E SEPAV/Gl-l JOHN C. MANOOG ATTORNEY Patented Apr. 5, 1949 UNITED STATES PATENT OFFICE CONTROL FOR-LOOM ELECTRONIC SYSTEMS Victor F. Sepavichand John C. Manoog, Worcester, Mass, assignors to Crompton & Knowles Loom Works, Worcester, Mass., a corporation of Massachusetts Application July 26, 1946, Serial No. 686,293

2 Claims.

This invention relates to improvements in an electronic weft detecting system for looms and his the general object of the invention to provide means by which said system will be instantly available for operation whenever loom operation starts.

Recently there have. been developed weftdetecting'systems using gas filled power-electronic tubes provided with cathodes which must attain; a given degree of" temperature before they by' a shipper handle. During extendedperiods of loom stoppage the shipper handle will be in the off position and themotor will be stopped.

When weaving is to be resumed the motor is first set. into motion by closure of itsswitchso that the motor and gearing moving with it can attain.

full. speed, after which the shipper handle is movedto running position to start-loom opera-. tion. Usually ashort interval of. time lapses between closure of the motor switch. and pulling of the shipper handle to running position. It is another object of our invention to provide electric means-by which. the cathode heat-- ingv transformer will be immediately energized as soon as the loom motor is setin motion and before theshipper handle is moved to-runningposition. During the aforesaid interval the cathode will. have sufiicient time to attain. proper temperature conditiona.v

It is afurther object of the invention to provide an electronic, weft. detecting. system. having a grid controlcircuit including a condenser one side of which is grounded to assist in maintaining normal preventive bias of the grid when the detector is not indicating Weft exhaustion. Upon indication of exhaustion this condenser is dischargedwiththe effect that the potential of the grid is altered to a permissive conditionwhicn will allow current to flow through the tube to initiate a change in loom operation.

It. is. a still further object of. the inventionv to providean. electric weft detector system of the electronic type having alow voltage detecting circuit to. controlthe grid; and a higherveltage circuit including the plate of the electronic-tube and the electromagnetic device which-whenener gized' initiates a change in loom operation. By?

this arrangement all danger of shock to the.

weaver is eliminated in the event that heshoul'd:

touch exposed parts of the weft detector, but the"- plate circuit operates at asufficiently high volt-'- age to insure energization of the electromagnetic device.

With these and other objects in view whi'chwill" appear as the description proceeds, our invention resides inthe combination and arrangement of parts hereinafter described and set forth.

In the accompanying drawing, wherein a convenient embodiment of our invention is set'forth:

The figure is a diagrammatic view illustrating the electric circuits and indicating also the relae tion between the loom motor and shipper mechanism.

Referring to the drawing, the loom has a bob bin B which is periodically presented to an electric weft detector D. The latter may be made in any approved manner but as shown has two ele'c' trodes insulated from each other for engagement with a metallic conducting body, such as a ferrule 85, on the bobbin when the latter is depleted during a detecting interval.

The loom frame has a motor 3! provided with a pinion 32 meshing with a driving gear 33 which is looseon the top shaft 34 of' the loom. The top shaft has fixed thereto a gear 35 meshing with the gear 36 twice its diameter secured to the bottom shaft 31. Referring particularly to the upper right hand part of the figure, the shipper mechanism designated generally at S includes a rod 38 attached by intermediate connectionsnot shown to the shipper handle (not shown) and also to a shipper lever 39 swingable on afixed pivot 40. A .clutch member M rotating withthe top shaft 34 is controlled :by lever 353V and is moved into engagement with clutch member 42 on gear 33whenever lever 39 rocks in a counterclockwise direction as viewed in the figure. In this way the motor is operatively connected to the shaft 34 and to the loom.

When the loom is idle for any extended period the motor 3| is at rest and the shipper. handle is in the off position to place shipper lever 39 in the position. shown in the figure. When weaving is to be resumed motor 3| is first set into operation as will bedescribed, and after enough time has been allowed for the motor and the gear 33 to attain full speed the shipper'handle is pulled on to the running position. As. loom motors are'generally made, except for the so..-i

called stop and start type, they are not able to operate the loom satisfactorily on the first pick if they are connected to the loom when first set in motion.

Referring to the figure, a transformer T has its primary 41 connected to wires 45 and 46 by wires 48 and 49, respectively. A gas filled or power electronic tube 50 has a plate 52, a cathode 53 which is indirectly heated by a filament 54, and has also a control grid 55.

The filament 54 derives low voltage electric power for its operation from a secondary winding 60 of transformer T. Filament 54 is in the following filament circuit: secondary 55, wire 62, filament 54, wires 63 and 64, ground G, up from the ground by wire 65 to junction 66, and thence back to the secondary by wire Bl. Whenever primary is energized by power from wires 45 and 46, therefore, filament 54 will be heated by current derived from secondary winding 60.

The grid control circuit is operated by direct current supplied by a rectifier I connected across secondary 50 by means of wires Ill, 16, I1 and 61. This rectifier is connected to the grid control circuit for the detecting system as follows: negative side of rectifier 15, wire 80, resistance R, wire 8|, the detector D, wire 82, ground G, and by grounded wire 65 and wire 83 back to the positive side of the rectifier. A condenser 84 of relatively small capacity connects wire 8| to the ground, and the grid 55 is connected to wire 8!. When ample weft is present during the weft detecting operation, wires BI and 82 will be electrically disconnected and the grid 55 will be at such a potential relatively to its cathode as to prevent firing of tube 55. When the detector engages a bare ferrule 85, Wires BI and 82 are connected and condenser 84 is discharged, and under these conditions the potential of the grid 55 is altered sufficiently to allow current to pass through tube 50.

The weft detector operating circuit derives its power from a secondary winding 81 of transformer T, and when grid 55 permits current to flow through tube 50 the operating circuit is completed as follows: secondary 81, wires 88, 89 and 90, relay 9!, wire 92, plate 52, through the tube to cathode 53, wire 64 to ground and up from ground and back to secondary 81 by way of wire 65. Current flowing in this circuit causes relay 9| to attract its armature 93, whereupon the secondary 81 energizes solenoid 94 forming part of the electric weft detecting system of the loom. It is not thought necessary to set forth in detail how energization of the relay causes operation of the weft detecting system for the purpose of initiating the weft replenishing operation of the loom, since such controls are well-known and may be as shown for instance in our copending applications Ser. Nos. 606,600, filed July 23, 1945, now Patent No. 2,429,529 and 674,921, filed June 6, 1946, now Patent No. 2,431,429.

All of the circuits traced hereinbefore derive their power from wires 45 and 45, and whenever the latter are energized the transformer winding for the heater filament circuit will heat cathode 53. In order to insure adequate heating of the cathode before loom operation begins we control energization of the wires 45 and 45 by a loom switch LS having two blades I90 and I9] connected at their lower ends to the principal power lines P and P. When switch LS is closed blades I90 and I 9| engage contacts I92 and I93, respectively, from which extend wires I94 and I95 leading directly to the loom driving motor 3I. Wires 45 and 46 are connected to the wires I95 and I94, respectively, at junctions I96 and I91, respectively. Whenever switch LS is closed to start operation of the loom motor 3|, therefore, wires 45 and 46 will be energized and the cathode will start to heat up. By the time the weaver is able to pull the shipper handle on after having started motor 3! the filament and its cathode will have attained operating temperature and the detector system will be instantly available for operation to perform its functions as soon as the loom starts running,

We do not wish to be limited to any particular values or magnitudes for the various electrical devices described, but we have found the following values satisfactory: Rectifier I5 to deliver 6 volts D. 0.; resistance R about 25,000 ohms, condenser 84 about 0.01 microfarads; and the voltage of the filament winding 60 approximately 6 volts.

The power lines P and P will ordinarily be part of a three-phase system such as is customarily employed for textile motors, but we have not shown the third wire since it does not enter into the operation of our invention.

From the foregoing it will be seen that we have provided means which insure efl'icient heating of the cathode of the electronic tube before loom operation can be started when the usual procedure of loom starting is followed. This result we accomplish by energizing the transformer T as soon as the main motor switch LS is closed, this latter occurring before the shipper mechanism is moved to running position. It will further be seen that the detecting system employs a low voltage detecting circuit to control the grid so that there is no danger of shock if the weaver should accidentally touch the exposed part of the weft detector D. Also, the detector circuit is grounded through condenser 84 which when discharged at the time of indication by the detector causes a change in the electric condition of the grid which permits current to flow through the tube 50.

Having thus described our invention it will be seen that changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the invention and we do not wish to be limited to the details herein disclosed, but what we claim is:

1. In a loom having a driving motor and a motor switch open when the motor is idle and closed to cause running of the motor, shipper mechanism operatively connecting the motor to the loom when in running position to cause operation of the loom and disconnecting the loom from the motor when in stopped position, an electromagnetic device which when energized effects a change in loom operation, an electric weft detector having two normally insulated electrodes which are electrically connected upon indication of weft exhaustion, a source of relatively low potential electric power energized when said motor switch is closed, an electronic tube having a plate, a filament energized to heat a cathode by said source whenever said motor switch is closed, and a grid, a detector circuit including said low potential source and detector connected to the grid and normally enabling the latter to prevent flow of current through the tube, a source of relatively high potential electric power, a plate circuit including said high potential source, device and plate tending normally to energize the device by current flowing through the tube but prevented from doing so by the grid, said detecting circuit effective when the electrodes of the detector are electrically connected to change the grid electrically so that electric current can flow through the tube from said high potential source to energize said device, and a grounded common connection between said sources of electric power.

2. In a weft detecting system for a loom having a driving motor and a motor switch open when the motor is idle and closed to cause running of the motor, shipper mechanism operatively connecting the motor to the loom when in running position to cause operation of the loom and disconnecting the loom from the motor when in stopped position, an electromagnetic device which when energized efiects a change in loom operation, an electric weft detector having two normally insulated electrodes which are electrically connected upon indication of weft exhaustion, a source of relatively low voltage electric power energized whenever said motor switch is closed, an electronic tube having a plate, a. filament energized to heat a cathode by said source whenever the motor switch is closed, and a grid, an electric condenser, a detector circuit means deriving power from said low voltage source and including said detector and condenser and connected to the grid and normally enabling the latter to prevent flow of current through the tube when said electrodes are electrically disconnected, a source of relatively high voltage electric power, and plate circuit means including said REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,802,820 Lindsjo Apr. 28, 1931 2,146,611 Young Feb. 7, 1939 2,233,483 Metcalf Mar. 4, 1941 2,346,240 Thomas Apr. 11, 1944 2,400,837 Nesterowicz May 21, 1946 FOREIGN PATENTS Number Country Date 400,132 Great Britain Oct. 19, 1933 587,951 Germany Nov. 10, 1933

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