US2436023A - Electric warp stop motion for looms - Google Patents

Description

Feb. 17, 1948. v. F. sPAvlcl-l ETAL 3 9 ELECTRIC WARP STOP MOTION FOR LOOMS Filed May 4, 1946 it In fri' 'n. 1-- ng ,A

I L1 L1 INVENTORS WGTOR F. SEPAVIGH JOHN G. MAM/00G .m ATTORN Y should pass through Patented Feb. 17, 1948 ELECTRIC WARP 831%]? MOTION FOR L Victor F. Sepavich'and John C. Manoog, Worces ter. Masa, assignors to Crompton d: Knowles Loom Works, of Massachusetts Worcester, Mass., a corporation Application May 4, 1916, Serial No. 667,294

- '23 Claims. (Cl. 139-353) and so related that when a drop wire falls .due to breakage of the associated warp the electrodes will be electrically connected or short circuited.

As heretofore made the warp stop mechanism has included a solenoid energized by a relatively large electric current which passes through the fallen drop wire. This arrangement results in heating and burning of the drop wire, and constitutes a fire hazard.

It is an important object of our present invention to provide an electronic circuit which will be controlled by the drop wires and which will be operated by a very small current incapable of causi s heatin or burning of the drop wires.

A loom can ordinarily be stopped by any one of several stopping mechanisms, such as the filling fork, protector, or warp stop motion, and it is not always easy for the weaver to know just which fault of loom operation has caused the stoppage. In order that the warp stop motion may give a signal when it is responsible for loom stoppage we use a lamp or other form of signal which will become illuminated whenever the warp stop mechanism operates. The current for operating the lamp will ordinarily be larger than that which the drop wire, and in order to prevent the lamp current from passing through the drop wire we connect the latter and lamp to the electronic circuit in such a way that a very small current flowing through the drop wire will cause illumination of the lamp.

After the weaver has determined by illumination of the lamp that loom stoppage has been caused by a warp fault, he may have difilculty in determining the location of the broken thread. In a type of electric warp stop motion heretofore developed. and shown in Payne Patent No. 1,852,217 there is employed a form of drop wire having an arch at the top thereof over a vertical slot into which project two ears or projections. When the drop wire falls these projections engage the electrodes of the contact bar to connect them electrically. When ally tilted its arch engages the upper part or the contact bar, after which further tilting will liit the projections and break the contact between the electrodes and the drop wire.

It is another object 01 our invention to utilize this breaking 01 contact between the drop wire and contact bar to alter the potential of the grid of the electronic tube and thus cause a change in the illumination of the lamp. By moving his hands over a bank of drop wires the weaver can readily determine the location 01' the fallen drop wire by noting the change in illumination 0! the lamp.

In the previously mentioned contact bars the electrodes are separated by a strip of insulating material which acts as a dielectric, causing the contact bar to act as an electric condenser. The strip of insulating material also has a high resistance, but this resistance varies with atmospheric conditions, being low when there is considerable moisture in the air and being high when the air is dry. These changes in atmospheric conditions also alter the capacitance oi the contact bars. The circuit for the grid of the electronic tube includes the contact bars and a resistance in series with them. These two resistances provide the normal bias of the grid,

but because of the changing resistance of the di-' electric it is necessary that the resistance in series with the contact bar be high enough to take care of all resistance conditions of the contact bar. When this resistance is high enough to produce a correct voltage at the grid when the contact bars are dry, it is found that the condenser action of the contact bars will permit firing of the tube in damp weather due to variation in the capacitance of the contact bar.

It is a further object of our invention to connect a condenser acrossthe electrodes of the contact bars and make its capacity much higher than that or the bars. In this way the total capacity of the grid circuits undergoes very little change even though considerable variation may exist in the capacitance of the bars themselves. The resistances can then be chosen with respect to resistance of a contact bar and be made of such value that the capacity of the circuit will never cause firing of the electronic tube.

. With these and other objects in view which will appear as the description proceeds, our invention resides in the combination and arrangement of parts hereinafter described and set forth.

the drop wire is manu- In the accompanying drawings, wherein a convenient embodiment of our invention is set forth,

'aasaoce the contact and warp supporting bars Fig. 3 is a diagrammatic view illustrating the manner in which the contact between the drop wire and the contact bar may be interrupted or disturbed for the purpose of determining the location of the broken thread,

Fig. 4 is a diagrammatic view showing the circuits employed in our invention, and

Fig. 5 is a diagrammatic view indicating the resistance and capacitance of four contact bars connected in parallel, indicating also a drop wire in two positions.

Referring particularly to Fig. 1. the loom frame l0 has top and bottom shafts H and I2 and harness frames two of which are indicated at l3. The warp beam H at the back of the loom supplies the warp W which passes upwardly and around a whip roll I! and then forwardly through the warp stop motion designated generally at A. From the warp stop motion the warp leads forwardly or to the leftas viewed in Fig. 1 through the harness frames and then to the fabric I8.

Operation of the loom is controlled by a shipper handle 20 to which is connected a rearwardly extending rod 2| attached as at 22 to an upright lever 23 forming part of a 100m stopping-or knockoff mechanism K. Lever 23 is pivoted as at 24 to the mechanism K and has a link 25 pivoted thereto and connected to the core 26 of a solenoid 21. Arlever 28 is pivoted on the knockoff mechanism and has an arm 29 which rests on a cam 20 secured to the bottom shaft I2. An actuating arm 3| on lever 28 is provided for operation of the link 25.

Under normal running conditions when the solenoid is not energized its core 26 and the link 25 will be in down position below the path of travel of the actuator arm 8| as lever 28 is oscillated due to rotation of cam 30. The shipper handle 20 will be in the forward running posiwhich causes the contact bar to have an electric capacitance.

The bank I has a plurality of drop wires one of which is shown at 46, Fig. 2. Slot 4'! in'the upper end of drop wire 46 receives the contact har Ears or projections 48 on drop wire 48 extend into the slot from the sides thereof, and the upper part of the drop wire has an arch or bridge 49 extending across the top thereof to connect the two sides of the drop wire on opposite sides of the slot.

Ordinarily, the drop wire 48 will be in the raised full line position shown in Fig. 2 with the ears or projections 48 in such position that they cannot electrically connect the electrodes 4| and 42. When the warp thread W breaks the drop wire will fall to the dotted line position shown tion shown in full lines, Fig. 1, and lever 23 will I be in the full line position shown in Fig. 1. Should the solenoid 21 be energized its core and link 25 will rise and upon the next oscillation of lever 28 in a counter-clockwise direction as viewed in Fig. 1 the actuator arm 3| will engage link 25 and move lever 22 to the dotted line position shown in Fig. 1, thereupon moving rod 2| to the left as viewed in Fig. l to rock the shipper handle from the running full line position to the stopped dotted line position.

Warp stop motions will ordinarily comprise several banks of drop wires each having its contact bar, and we have shown herein four banks I, II. III and IV. These banks and their contact bars are alike and a detailed description will be given for bank I only. The contact bar 40 of bank I is formed of an outer and normally grounded electrode 4| which is suitably supported at the sides of the loom. Within the grounded electrode is a second or live electrode 42 insulated from the inclosing electrode 4| by a strip 43 of insulating material. The upper part of the grounded electrode is round as at 44 and extends above electrode 42. Separator bars 45 supportthe warp W and are related to the contact bar 40 as indicated in Fig, 2. Insulation 43 has a high resistance which varies due to atmospheric changes, and is also a dielectric 7s in Fig. 2, whereupon the left hand projection 48 will engage a rib 50 extending longitudinally of the outside electrode 4|. This rib causes a camming of the drop wire to the left, Fig. 2, thereby moving the right hand projection as against the insulated electrode 42. The two electrodes are thus electrically connected and the arch or bridge 48 is located only a short distance above the upper rounded edge 44 of the electrode 4|. Y

The matter thus far described may be made as set forth in theaforesaid patent to Payne and also another of his patents No. 1,873,465.

In carrying our present invention into effect we provide improved means whereby electric connection of the electrodes 4| and 42 will cause operation of an electronic circuit for the purpose of energizing the solenoid 21 andilluminating a signal. The electric circuit'shown in Fig. 4 includes a gas filled electronic tube E having plate P, grid G, shield grid SG, andcathode C which is heated by a filament F. The alternating current power lines L and L are connected, respectively, to binding posts 52 and 53 which in turn are connected to the primary 54 of a transformer T. The transformer has a low voltage winding 55 for the filament F, and has also a higher voltage winding 56. n

The circuit for the filament F of the electronic tube is as follows: ground G, wire 60, secondary winding 55, wire 6|, wire 62, filament F, wire 68, and wires 64 and 65 to ground G2. This cir-' cult remains closed during loom' operation and the filament heats the cathode C. The latter is'connected by wire 66 to wires 63 and. 64 and has a potential bias due to flow of current in the filament circuit.

The circuit for grid G is as follows: ground G, wire 61, full wave rectifier 88, wire 69, re-

sistance R, wire Ill, connection I I thence through v two branches one of which includes wire l2 and condenser 13 to the ground, and the other of I .which includes wire 14, insulated electrode 42. the strip of insulation. acting as a high resistance, and outside electrode 4| to ground G4.

The resistance of the dielectric or strip of insulating material 43 varies considerably due to atmospheric changes, as already mentioned, changing from a high value of several megohms under dry atmospheric conditions to a, much electric. 4 When the dielectric is of low resistance the contactbar has a relatively low electric capacitance, a condition which might result in raising Resistance.

sweeps:

than that of the barn/'5 The resistance R can then be chosen with reference to the resistance of the dielectric and of such value that the combined condenser eifect of the contact bar and the condenser [3 will not cause undesirable firing of the tube E.

The tubeis thus maintained in idle or nonfiring condition so long as the drop wire is raised. When the drop wire 48 falls it electrically connects the electrodes ti and t2, thereby shortcircuiting the resistance of the dielectric t3 and causing an increase in the voltage of the grid G,

whereupon current can flow through thetube E in the following plate or relay circuit: ground G.

' wire 80, secondary winding 58, wire 8i, relay @2 and condenser 83 in parallel with each other, wire M, plate P, through the tube to the cathode 0,

its

and wires 66, 6t and 85 to the ground G2. Cur- I rent in this circuit is alternating and flows only when the plate P is positive. The condenser 83 is for the purpose Of-dlSOh&1gll1g into the relay $2 to continue energization of it whenthe plate P is negative.

When relay 82 is energized it closes two switches S and 8', one for the solenoid and the other for a signal circuit. Closure of switch S completes the following solenoid circuit: ground G3, low voltage (12 volts) winding 85 of the second transformer T, wire 88, shipper handle control nor-- mally closed switch e1. wire 88, solenoid 21, wire 39, switch S and wire 90 to ground 66. This circuit causes energization of the solenoid with resultant operation of the knockoff mechanism K, and when the shipper handle moves from the full to the dotted line position of Fig. 1, switch 8! will be opened, thereby breaking the solenoid circuit to prevent further flow in it of the relatively high current required for the solenoid.

When switch S is closed by the relay, the following signal circuit is closed: ground G, wire til, winding 55 (6 volts), wires 8i and B2, switch 8', lamp 9i and ground G6. This lamp circuit remains closed so' long as the relay 82 remains energized, and this latter condition will continue so long as the tube is kept in firing condition by the fallen drop wire.

As already indicated it is desirable that the weaver be able to locate the fallen drop wire, and he may do this by running his hand over the bank of drop wires and watching the lamp 9i. Whenever illumination of the latter changes he will have reached the fallen drop wire. Referring to Fig. 3, the drop wire is indicated in down or circuit closing position in full lines, in which position one of the ears t8 contacts the insulated electrode t2. As the hand is moved over the bank of drop wires the fallen drop wire is first tilted wire establishes around 6 Lamp ii is thus extinguished and gives a visual indication to the weaver that his hand is over the fallen drop wire.

The foregoing description has been given responding to that shown in full lines in Fig. 3,

and all of the contact bars are electrically connected through the fallen drop wire, since the electrodes 4: are connected in parallel; The drop wire is connected across the resistance and capacitance of all the contact bars, and thereby discharges whatever charge may have accumulated on the bars because of their action as electric condensers. This discharge, however, does not aflect the circuit materially, since these condensers are also in parallel with the relatively high capacity condenser '53 (approximately .01 microfarad). A second warp breakage occurring immediately after the repair of a previous breakage will not result in delayed or improper indication as a result of discharge of charges on the contact bars. In Fig. 5 the dot and dash position of the drop wire corresponds to the similarly indicated position in Fig. 3.

From the foregoing it will be seen that we have provided an electric warp stop motion including electronic circuits which stopping the loom by the use of a very small current such as eliminates heating of the drop wire and tire hazard. It will also be seen that the lamp 9i can have its illumination altered to indicate the location of a fallen drop wire by disturbance of the grid circuit, more specifically by removing the short-circuit which the fallen drop thedielectric M. It will also be seen that the condenser 73 is in parallel with the contact bars and has a much higher capacitance than do the bars, so that variation in the capacitance of the bars due for instance to atmospheric conditions will have practically no eilect on the grid circuit. The grid circuit operates at low voltage direct current rectifier 68 powered by winding 55, and there is no danger of shock when the weaver passes his hand over a bank of drop wires. The tube E requires a higher voltage due to its own internal resistance and that of the relay, but the winding 56 which supplies this higher voltage does not supply the electric power for the grid circuit.

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 to the dotted line position shown in Fig. 3 to cause and we do not wish to be limited to the details herein disclosed, but what we claim is:

1. In an electric warp stop motion for a loom having an electromagnetic device which when energized effects loom stoppage and wherein a fallen drop .wire electrically connects two insulated electrodes of a contact bar, a source of electric power, an electronic tube including a grid,-electric circuit means including the source, tube and electromagneticv device normally main tained inoperative by the grid when the aforesaid electrodes are not electrically connected, and electric means controlled by said drop wire and eilective upon electric connection of electrodes permit an indication for supplied by by said drop wires thereby to efiect a change in the grid and thereby enable said electric circuit mans to energize the electromagnetic device.

2. In an electric warp stop motion for a loom having an electromagnetic device which when energized effects loom stoppage and wherein a fallen drop wire electrically connects two insulated electrodes of a contact bar, a'source of electric power, an electronic tube, electric circuit means including the source, tube and electro' magnetic devices, a grid in the tube normally operative to prevent flow of electric current in said electric circuit means; and electricconnections between said electrodes and grid edective to alter the latter and thereby permit said electric circuit means to energize the electromagnetic device when the aforesaid electrodes are electrically connected by the fallen drop 3. In an electric warp stop motion for a loom having an electromagnetic device which when.

energized effects loom stoppa e and wherein a fallen drop wire electrically connects two inaulated electrodes of a'contact bar, a source of electric power, an electronic tube having agrid, electric circuit means includlng'the source, tube anddevice tending normally to energize said detrically connecting said electrodes to short-cir- 7 prevent passage vice but prevented from doing so by the normal v electric condition of the grid when said electrodes are electrically disconnected, and elcc tricmeans connected to the grid and ren'deredoperative by -electric connectionof said electrodes by the fallen drop wire to alter the electric condition of said grid insuch manner as means to energize said device.

4. In an electric warpstop motion fora loom having an electromagnetic device which when energized effects loom stoppage and wherein a contact bar comprising two electrodes-separated by a high resistance dielectric are electrically connected by a drop wire when the latter falls incident to warp fault, said contact bar due to the electrodes and dielectric havingan electric capacitance, a source of electrlcpower, an electronic-tube including a grid, electric circuit means including the source, tube and electromagnetic device, and grid circuit meansincluding said to enable said circuit cult, the resistance of said dielectric and thereby alter the potential ofv the grid in such manner that electric current can flow through said tube and in said electric circuit means to energize saidiflectromagnetic device.

6. In an electric warp stop motion for a loom having an electromagnetic device which when energized effects loom stoppage and wherein a fallen, drop wire electrically connects two in aulated electrodes of a contact bar, an electronic tube having. a grid, a source of relatively high voltage electric power, electric circuit means including said source, tube and electromagnetic device effective when current can flow through 'said. .tube to energize said device, a second source of relatively low voltage electric power, and grid circuit means including said second source and said electrodes and efiective when the latter are electrically disconnected to enable said grid to of electric current through said tube, electric connection of said electrodes by a fallen drop wire causing said grid circuit means to alterthe electric potential of said grid in such manner as to enable electric current to flow through said tube and electric circuit means to energize said device;

I. In an electric warp stop motion for a loom having an electromagnetic device which when energized effects loom stoppage and having a contact bar comprising two insulated electrodes,

includlngjsaid source and said contact bar concontact bar and a condenser connected in parallel 1 with the electrodes -of said bar and normally eflective to maintainsaid grid at'such electric potential as will prevent electric current 'irom' flowing through said electric circuit means, said drop wire when fallen electrically connecting said electrodes andshort-circuiting said'high resistance dielectric and; causing a change in the electric condition of said grid'enabling said electric circuit means to energize said electromagnetic device.

nectedto the grid and maintaining the latter at a normal bias effective to prevent flow of electric current through the tube when said electrodes are not electrically connected, a source of relatively high voltage electric power, and electric circuit means including the second source, tube and electromagnetic device normally inoperative ltoedergize said device due to the normal bias. of the grid, said electrodes when electrically connected by a fallen drop wire altering said grid circuit in, such manner as to raise the potential of the grid to permit electric current to flow through the tube and enable said electric circuit 'mcanstoenergize, said electromagnetic device.

5. In an electric ivarp stop motion for a loom having an electromagnetic device which when energized effects looni'v toppage and wherein two electrodes ,of a contact bar separated by a high resistance dielectric are connected electrically when a drop wire falls, said contact bar due to the electrodes and dielectric acting as an electric condenser, a source of electric power. an electronic' tube including a grid, an electric condenser, grid circuit means including a resistance and having said electrodes connected electrically inparallel with said condenser, said grid being electrically connected to said grid circuit means between said resistance and said electrodes and normally" preventing flow of electric current through said grid, and electric circuit means including said source, tube and electromagnetic device normally maintained inoperative by the grid II 8. In an electric warp stop motion for a. loom having an. electromagnetic device which when energized effects loom stoppage, the loom having a'conta'ct bar comprising two electrodes separated by a high resistance dielectric, an electronic tube including a grid, a resistance having a lower ohmic value than the ohmic value of said dielectrio, a source of relatively low voltage electric power, grid circuit means including said source, resistance, and dielectric and normally eiIective to maintain the grid at such potential bias as to prevent passage-of electric current through the tube, said electrodes when electrically connected 'by a fallen drop wire altering said grid circuit in such manner that the grid permits flow of electric current through the tube, a source of relatively high voltage electric power, and electric circuitmeans including the second source, tube and electromagneticdevice effective to energize the'latter when the grid is at such potentiai as to permit electric current to flow through said tube.

9 In an electric warp stop motion for a loom energized efl'ects' loom stoppage, the loom havin a contact bar comprising two electrodes connectible electrically by a fallen drop wire and sepa-.

rated electrically by a high resistance dielectric which together with the electrodes causes the contact bar to act as an electric condenser. an electronic tube having a grid, a source 01 rela tively low voltage electric power, a, resistance having an ohmic value less than the ohmic value of said dielectric, a grid circuit including said source, r esistance, electrodes and dielectric connected in series and connected to the grid between said resistance and said electrodes, a, condenser having a higher capacitance than the capacitance of the contact bar connected to said grid .circuit in parallel with said electrodes, said grid circuit normally enabling said grid to prevent fiow of electric current through said tube when said electrodes are not electrically connected by the drop wire, a second source of relatively high voltage electric power, and electric circuit means including said second source, tube and electromagnetic device normally prevented from energizing the latter, said electrodes when electrically connected by the fallen drop wire shortcircuiting the resistance of the dielectric and causing a change in the grid circuit which enables said electric circuit means to energize said electromagnetic device.

10. In an electric warp stop motion for a loom having an electromagnetic device which when energized eiiects loom stoppage, a contact bar having two electrodes separated by a high resistance dielectric, an electronic tube having a grid, a source of electric ing said source, electrodes and dielectric and normally eifective to maintain the grid at such a potential as to prevent passage of electric current through the tube, a second source of electric power, and electric circuit means including said second source. tube and electromagnetic device normally prevented from energizing-said device by said grid but effective to energize said device by current flowing through the tube when the resistance of said dielectric is short-clrcuited by electric connection of the electrodes. 11. In an electric warp stop motion for a loom having an electromagnetic device which when energized efiects loom stoppage and wherein two electrodes of a contact bar separated by a high resistance dielectric are connected electrically when a drop wire falls, electric circuit means including an electronic tube with a grid and said device and tending to energize the latter, and a rid circuit means including said electrodes and dielectric and normally enabling said grid to prevent flow of electric current in said electric circuit means when the electrodes are not electrically connected by a drop wire, the drop wire when fallen electrically connecting said electrodes to short-circuit said dielectric and said grid circuit altering the grid in such manner as to permit flow of electric current in said electric circuit means.

12. In an electric warp stop motion for a loom having a lamp to be illuminated upon occurrence oi a warp fault, a contact bar having two electrodes insulated by a high resistance dielectric, an electronic tube having a grid, a source of relatively low voltage electric power, a grid circuit including said source, electrodes and said dielectric normally enabling the grid to prevent flow of electric current through the tube, an electromagnetic relay,

electric circuit means ener izin said relay when current flows through said tube, a switch closed by said relay when the latter is energized, and a second circuit normally open and including said electrodes when connected electrically to shortcircuit the resistance of said dielectric altering the grid circuit and enabling said electric circuit power, a grid circuit includthe electrodes, a source 'including the tube means to energize said relay to close said switch, whereupon said lamp is illuminated and said grid is maintained in a condition enabling current to pass through said tube so long as said electrodes are electrically connected.

13. In a warp stop a lamp to beilluminated upon occurrence of warp fault, a source of low voltage alternating current, a rectifier energized by said source, an electronic tube having a grid, a contact bar having two electrodes separated by a hlghresistance dielectric, a, grid circuit including said rectifier, electrodes and dielectric normally effective to enable a grid to prevent passage of electric current through the tube, an electromagnetic relay,

rent through the tube so long as said electrodes are electrically connected,

14. In an electric warp stop motion for a loom having a drop wire which when in fallen position due to warp breakage contacts two electrodes of a bar, the loom having an electric lamp to be illuminated upon contact of the drop wire with of electric power, an electronic tube, a relay, electric circuit means includingthe source, tube and relay tending normally to energize the latter, a grid forming part of the tube which when in normal electric condition when said drop wire is out of contact with both electrodes prevents said electric circuit means from energizing said relay, electric means operative upon contact of said drop wire with both electrodes to alter the normal electric condition of said grid and enable said electric circuit means to operate said relay, and electric power means separate from said electric circuit means causing illumination of said lamp when said relay is energized.

15. In an electric warp stop motion for a loom having a drop wire which when in fallen position I due to warp breakage closes contact with a con tact bar, the loom having an electric lamp to be illuminated upon operation of the warp stop motion, an electronic tube, electric circuit means normally tending to cause current to flow through said tube, electric power means separate from said electric circuit means operative when current flows through the tube to cause illumination of the lamp, a grid forming part of the tube and-acting normally to prevent passage of current in said circuit means and through the tube, and electric means operative when said contact is closed at the contact bar to alter the grid to permit electric current to pass through the electric circuit means and said tube.

16. In an electric w rp stop motion for a loom hnvlna a An. mi..- ...e i

source, switch and lamp, said motion for a loom having electric circuit .means including said'electronic-tube and relay aeeems due to warp breakage closes contact with a contact bar, the loom having an electric lamp to be illuminated upon operation of the warp stop motion, an electronic tube, a source of electric power, electric circuit means including said source and tube-tending normally to cause electric current to pass through said tube, means separate from said electric circuit'means causin illumination of said lamp when current passes through the tube, a grid in the tube which when in normal electric condition when said contact is open prevents electric current from passing through said tube. and-electric means operative when the contact is closed at the contact bar by the fallen drop wire to alter the electric condition of said grid to enable said electric circuit means to cause current to pass through said tube.

17. In an electric warp stop motion for a loom having a drop wire which when in fallen position due to warp breakage closes contact with a contact bar, the loom having an electric lamp to be illuminated upon operation of the warp stop motion, an electronic tube, electric circuit means tending normally to cause electric current to flow through said tube, means separate from said electric circuit means opcrative when current flows through the tube to cause illumination of said lamp, a grid in the tube which when in normal electric condition prevents current from flowing through the tube, and electric circuitmeans operative when said contact is closed at the con-, tact bar to,alter the normal electric condition of said grid and enable said electric circuit means to cause electric current to ilow through said tube.

18. In an electric warp stopmotion for a loom having a drop wire which when in fallen position due to warp breakage closes contact with a contact bar, the loom-having an electric lamp to be illuminated upon operation of the warp stop motion, an electronic tube, electric circuit means tending normally to cause current to flow through said tube, electric power means, separate from said electric circuit means so related to said lamp and electric circuit means that when current flows in the latter the lamp is illuminated, a grid in the tube the normal electric condition of which prevents current from flowing through said tube when said contact at the contact bar is open. andelectric means operative upon closure of said contact at the contact bar to alter the electric conditioner the grid and restrain the latter from preventing current from flowing in said circuit means through said tube, thereby enabling current to flow in said circuit means through said tube and causing illumination of the lamp.

19. In an electric warp stop motion for a loom having an electric contact bar comprising two electrodes insulated from each other and a drop wire which when in fallen position electrically connects said electrodes, said drop wire being manually tiltable when in fallen position to break said contact, an electric lamp, an electronic tube,

a source of electric power, electric circuit means tending normally to cause current to flow from said source through said tube, electric power means separate from said electric circuit means so related to the lamp and tube'that whenever current flows through the tube the lamp will be illuminated, a grid in the tube which when in normal electric condition when said contact is open prevents current from passing through the tube, and electric means operative when said contact is closed to alter the normal'electric condi- 1 12 tion of the grid to permit current to flow in said circuit means and through the tube. the normal electric condition of grid being restored to interrupt iiowof current through the tube when said I drop wire is manually tilted to break said contact.

20. In an electric warp stop motion for a loom having an electric contact bar comprising two electrodes insulated from eachother and a drop wire which when in fallen position closes a contact between said electrodes, said drop wire when in fallen position being manually tiltable to inter iupt contact between said electrodes, an electronic tube including a grid normally operative to prevent'flow of current through the tube when said contact is open, electric circuit means tending normally to cause electric current to flow through said tube,, electric means operating when said contact is" closed to alter the electric condition of said .grid to permit current to flow in said circuit means and through the tube, an electric lamp, and electric means separate from said electric circuit means causing illumination of the lamp when current flows through said tube, the normal condition of said grid be ng restored when the drop wire is in fallen position and is tilted to break said contact, thereby altering the illumination of said lamp.

21. In an electric warp stop mot on for a loomhaving an electric contact bar comprising two electrodes insulated from each other and having a drop wire which when in fallen position closes a warp stop contact between said electrodes, said drop wire when in fallen position being manually tiltable to open said warp stop contact. a source of electric power, an electronic tube, a lamp contact, an electromagnetic device which when energized closes said lamp contact. electric circuit means including said source, tube and device tending normally to cause electric current to flow through the tube and energize said device, a grid in the tube normally operative to prevent flow of current in said electric circuit means when said contact is open, electric connections between the contact bar and grid effective to alter said grid in such manner as to enable the electric circuit means to cause current to flow through the tube and energize said device when said contact is closed by the fallen drop wire, an electric lamp, and electric means separate from said electric circuit means to cause illumination of the lamp when said lamp contact is closed by the device, manual tilting of the drop wire when the latter is in fallen position to cause breaking of said warp stop contact resultin in interru tion of the flow of current in said electric circuit means to cause deenergization of said device and opening of said lamp contact.

22. In an electric warp stop motion for a loom having an electric contact bar comprisin two electrodes insulated from each other and having a drop wire which when in fallen position closes a contact between said electrodes. said dro wire when in fallen position being manuall 'tiltable to open said contact, a source of electric power, an electronic tube having a grid, electric circuit means normally tending to cause current to flow throu h said tube. said arid normally preventing current from flowing through the tube when said contact is open. electric means operative upon closure of said contact to alter the grid in such manner as to enable electric current to pass throu h said tube. an electric lamp. and electric means se arate from said electric circuit means 7 causing illumination of said lamp whenever curl3 rent passes through said tube, tilting of said fallen drop wire to break said contact causing the grid to interrupt the flow of current through the tube and prevent illumination 01 said lamp.

23. Control means for the electric warp stop 5 motion 01' a loom having an electromagnetic device which efiects loom stoppage when energized under control of a fallen drop wire electrically connecting two insulated electrodes of a contact bar. electric circuit means including said eiectro- I magnetic device and an electronic tube having a control grid which normally maintains said tube and circuit means inoperativ and electric means whereby upon the electrical connection 0! said insulated electrodes by said drop wire the s unanimous CITED The following references are of record in the 0 file of this patent:

UNITED STATES PATENTS Number Name Date 2,233,483 Metcair Mar. 4. 1941 2,391,591 Payne Dec. 25, 1945 2,410,687 Sepavich Nov. 5. 194B

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