US2622224A - Arc lamp - Google Patents

Description

Dec. 16, 1952 Filed Dec.

A. J. HATCH Fl G.-

ARC LAMP J. HATCH INVENTOR ARTHUR ATTORNEY Dec. 16, 1952 A HATCH 2,622,224

ARC LAMP Filed Dec. 17 1949 5 Sheets-Sheet 2 zol 204 A FIGrZ 202 ARTHUR J. HATCH INVENTOR ATTORNEY A. J. HATCH ARC LAMP Filed Dec. 1'7. 1949 FI G. 3

5 Sheets-$heet 3 J. HATCH ARTHUR INVENTOR ATTORNEY Patented Dec. 16, 1952 ARC LAMP Arthur J. Hatch, Toledo, Ohio, assignor to The Strong Electric Corporation, Toledo, Ohio, a corporation of Delaware Application December 17, 1949, Serial No. 133,577

14 Claims. 1

My invention relates to are lamps, and the principal object of my invention is to provide mechanism constructed and arranged to automatically maintain a substantially constant combined rate of feed of the lamp electrodes, thereby to automatically maintain the quality of the arc, and also to automatically maintain the arc substantially at a predetermined location.

In the drawings accompanying this specification and forming a part of this application I have shown for purposes of illustration what I now consider to be the best modes of carrying my invention into practice, and in these drawlugs:

any mechanism suitable for the purpose, in each of the present embodiments I have indicated it as comprising an electric switch 2| including a bi-metallic arm 22 and a cooperating stationary contact 23, a housing 24 enclosing the switch 2| and provided with an opening 25, and a lens 26 constructed and arranged, upon recession of the crater I4, to direct light from the crater l4 through the opening 25 onto the bi-metallic arm 22 and thereby cause the arm 22 to move into contact with the cooperating stationary contact 23 and close the switch 2 I.

Similarly, in each of the embodiments of Figures 1 through 4 I have shown the positive elec- Figure 1 is a partially diagrammatic View iltrede ll carried y a al a p 21 f in lustrating one such embodiment of my invenpar f a p iv electrode arri r 3 the n tion; tive electrode I2 carried by a metal clamp 28 Figure 2 is a partially diagrammatic view illusforming part of a negative electrode carrier 32, trating a second such embodiment; and the positive and negative electrode carriers Figure 3 is a partially diagrammatic view il- 31 32 supp and r p abl y m ans lustrating a third such embodiment; of a pair of carrying and actuating shafts 33 and Figure 4 is a partially diagrammatic i iu 34 each comprising a screw-threaded section 35 trating a fourth such embodiment; and 36 engaging pe v y in a c0 resp0 Figure 5 is a partially diagrammatic view illus- Screw-threaded Opening 38 in O latera trating a fifth such embodiment, portion of the positive or negative electrode car- As will be understood by those skilled in the art, my invention finds application particularly in respect of arc lamps of the types wherein the lamp comprises one or more reflectors or lenses or the like, constituting with the arc an optical system designed to produce a desired light formation, and wherein therefore it is necessary that the arc shall be maintained at a predetermined location, to properly coact with the remainder of the optical system.

However, commonly such lamps are designed for operation on direct current, and to produce a great preponderance of the light at a crater in the end of the positive electrode, and to utilize particularly the light emitted from this crater, and under these circumstances, maintaining the arc substantially at a predetermined location is essentially a matter of maintaining the tip or crater of the positive electrode substantially at a predetermined location.

Accordingly, although my invention is not limited thereto, I have illustrated it in respect of a lamp of the above described characteristics, and as functioning to automatically maintain the tip or crater of the positive electrode substantially at a predetermined location.

Therefore in each of the present embodiments I have indicated a positive electrode II, a negative electrode I2. a reflector I3 positioned to receive the light from the crater I4 in the end of rier 3| or 32, and a smooth section 39 or 40 extending through a closely fitting opening 4| or 42 respectively in the other lateral portion of the negative electrode holder 32 and an integral boss 43, and in the other lateral portion of the positive electrode holder 3| and an integral boss 44.

Accordingly, rotation of the one shaft 33 will reciprocate the positive electrode holder 3| along the other shaft 34, thereby to advance or retract the positive electrode II, and rotation of the other shaft 34 will reciprocate the negative electrode holder 32 along the one shaft 33, thereby to advance or retract the negative electrode I2, and the respective bosses 44 or 43 will operate to prevent cooking or binding of the electrode holder 3| or 32 and to insure direct reciprocation of the respective electrode II or I2.

With the foregoing, in the embodiment of Figure 1 the positive electrode II is connected by a main positive conductor IIII extending from the positive electrode clamp 21 to a positive connection terminal I02, the negative electrode I2 is connected by a main negative conductor I33 extending from the negative electrode clamp 28 to a negative connection terminal I34, and suitable rotation of the shafts 33 and 34, and thus suitable reciprocation of the positive and negative electrodes II and I2, are effected by means of a pair of shunt-connected direct-current motors III) and I20.

As herein shown the motor IIO comprises a fixed frame III field coils II 2 mounted on pole pieces II3 carried by the frame III, an armature H4 and commutator H5 carried by a shaft H6 rotatable in bearings II? supported by the frame III, and brushes H3 and H3 mounted on the frame III and coacting with the commutator H5, and the motor I23 comprises a frame I2I carried by the shaft N6 of the motor lid, field coils I22 mounted on pole pieces I23 carried by the frame I2I, an armature I2 1 and commutator I25 carried by a shaft I23 rotatable in bearings I2? supported by the frame I2I, and brushes I23 and I29 mounted on the frame IZI and coasting with the commutator I25.

In the present embodiment the motor I22 is additionally supported by a fixed bracket I33 comprising an upstanding portion I3I carrying a bearing I32 receiving the outer end of the shaft I25 of the motor I23, and connection is made to the motor I23 by means of three slip rings mounted on the exterior of the motor frame I2I and engaged by contact brushes supported on the bracket I33, namely, a first ring I33 connected to one terminal of the field coils I22 and engaged by a first contact brush I33, a second ring I35 connected to the commutator brush I23 and engaged by a second contact brush I36, and a third ring I37 connected to the other terminal of the field coils I22 and the other commutator brush I29 and engaged by a third contact brush I38.

Further, in the present embodiment the shaft I I6 of the motor III) is connected to the negative electrode actuating shaft 32 by a suitable drive indicated by the reference numeral I23 and shown as including a suitable speed reducing mechanism MI, the shaft I 23 of the motor I20 is connected to the positive electrode actuating shaft 33 by a suitable drive indicated by the reference numeral I42 and shown as including a suitable speed reducing mechanism I43, the armatures H4 and I24 of the motors III] and I 23 are connected directly to the main positive and negative conductors IilI and'I I13, the field J coils II3 of the motor II I) are connected to the main positive and negative conductors IKJI and I03 in' series with an adjusting rheostat I44 and a control resistor I45, the field coils I23 of the motor I23 are connected to the main positive and negative conductors NH and I33 in series with an adjusting rheostat I43, and the electric switch 2I of the control means I5 is connected in shunt across the control resistor I23.

As herein shown the above electrical connections are accomplished by a conductor I58 extending from the main positive conductor IllI to the commutator brush III! of the motor Ht, to one terminal of the field coils H3 of the motor III), and to the contact brush I38 of the motor I20 and thereby to the brush I23 and one terminal of the field coils I23 of the motor I23, a conductor I5I extending from the main negative conductor I I33 to the other commutator brush II8 of the motor IIB, to one terminal of the adjusting rheostat I43 of the motor I20, and to the contact brush I33 of the motor I20 and thus to the commutator brush I28 of the motor I23, a conductor I52 extending from the other terminal of the adjusting rheostat I26 to the contact brush I34 of the motor I23 and thus to the other terminal of the field coils I23 of the motor I20, a conductor I53 extending from the other terminal of the field coils II3 of the motor III! to one terminal of the adjusting rheostat I44 of the motor Hit, a conductor I54 extending from the other terminal of the adjusting rheostat I44 to one terminal of the control resistance I45, a conductor I55 extending from the other terminal of the control resistance I45 to the main 4 negative conductor I33, a conductor I56 extending from the conductor I54 to the stationary contact 23 of the switch 2I, and a conductor I5? extending from the bi-metallic arm 22 of the switch 2| to the main negative conductor With the described arrangement, the frame of the motor IIQ being fixed, the shaft IIS of the motor IIEI will rotate at the speed of the motor I I0. However, the frame of the motor I23 being mounted on the shaft I I3 of the motor I I0, under the conditions that the motors I I3 are connected to rotate in opposite directions and the speed of the motor I2IJ is always greater than the speed of the motor III the speed of the shaft I26 of the motor I20 will be numerically the speed of the motor I26 less the speed of the shaft I I6 of the motor H3. On the other hand, the sum of the speeds of the shafts I I6 and I23, being therefore the speed of the shaft I16 plus the speed of the motor I23 less the speed of the shaft H 6, will always be numerically the speed of the motorIZfi.

Thus under the condition that the speed of the actor I28 is always greater than the speed of the motor I I0, and inasmuch as the rates offeed of the positive and negative electrodes II and I2 are a fixed proportion respectively of the speed of the shaft I23 of the motor I20 and of the speed of the shaft IIB of the motor IIO, thereforethe sum of the rates of feed of the positive and negative electrodes II and I2 will always be numerically the fixed proportion of the speed of the motor I20, and on the other hand, the rate of feed of either electrodes will always be numerically the sum of the rates of feed of the twoelectrodes less the rate of feed of the other electrode.

Under these circumstances, with the described arrangement the adjusting rheostat I43 of the motor I20 is set to produce a speed of the motor I23 providing a combined rate of feed of the positive and negative electrodes II and I2'numerically equal to the sum of the burning rates of the two electrodes at the current at which the lamp is desired to be operated, and thus the two electrodes will automatically be fed at that rate, and therefore the quality of the arc will automatically be properly maintained.

However, to maintain the crater I4 of the positive electrode II at'the proper location, the adjusting rheostat I44 of the motor H3 is set to produce a speed of the motor III) and its shaft IIG such that the rate of feed of the negative electrode I2 is slightly greater than the actual burning rate, and therefore the rate of feed of the positive electrode I I is slightly less than its actual burning rate.

Thus the crater Id of the'positive electrode II will begin to recede, but before it has proceeded sufficiently to depart from position to coact fully with the remainder of the optical system, light from the crater I4 will become directed bythe lens 26 through the opening 25 in the switch housing 24, onto the bi-metallic arm 22 of the switch 2 I, and will cause the arm 22 to come into engagement with the cooperating stationary contact 23, thereby closing the switch 2I and shunting the control resistor I45,- and consequently decreasing the speed of the motor IIO", decreasing the rate of feed of the negative electrode I2, and increasing the rate of feed of the positive electrode I I.

The control resistance I45 being of suitable value, the altered rate of feed of the positive electrode II will be slightly greater than its actual rate of burning, and thus the crater [4 will become restored to its previous position, whereupon the lens 26 will no longer direct light from the crater l4 through the opening 24, the arm 22 will withdraw from the cooperating stationary contact. 23 and convert the switch 2| to open condition, and thus the shunt will be removed from the control resistor I45, and the mechanism will be restored to its previous condition.

Thus the described embodiment functions automatically both to maintain proper total feed of the electrodes and also to maintain the are at the proper location, and thus to automatically maintain both proper quality of the arc and optical relation.

In the embodiment of Figure 2 the positive electrode is connected by a main positive conductor 20| extending from the positive electrode clamp 21 to a positive connection terminal 202, and the negative electrode |2 is connected by a main negative conductor 203 extending from the negative electrode clamp 28 to a negative connection terminal 204, and suitable rotation of the shafts 33 and 34, and thus suitable reciprocation of the positive and negative electrodes II and I2, are effected by main and auxiliary shuntconected direct- current motors 205 and 206 having their armatures 201 and 208 connected directly across the main positive and negative conductors 20| and 203 and their fields 209 and H0 connected across the conductors 20| and 203 in series respectively with a main motor adjusting rheostat 2| I and with an auxiliary motor adjusting rheostat 2|2 and a control resistance 2|3 arranged to be shunted by the switch 2|.

As herein shown the above electrical connections are accomplished by a conductor 220 extending from the main positive conductor 20| to one terminal of the control resistance 2| 3, one terminal of the auxiliary motor armature 208, one terminal of the main motor adjusting rheostat 2| and one terminal of the main motor armature 201, a conductor 22| extending from the other terminal of the main motor adjusting rheostat 2|| to one terminal of the main motor field 209, a conductor 222 extending from the other terminal of the main motor armature 201 and the other terminal of the main motor field 209, to the main negative conductor 203, a conductor 223 extending from the other terminal of the control resistance 2|3 to one terminal of the auxiliary motor adjusting rheostat 2|2, a conductor 224 extending from the other terminal of the auxiliary motor control rheostat 2|2 to one terminal of the auxiliary motor field 2 0, a conductor 225 extending from the other terminal of the auxiliary motor armature 208 and the other terminal of the auxiliary motor field 2|0, to the main negative conductor 203, a conductor 226 extending from one terminal of the control resistance 2|3 to the bi-metallic arm 22 of the switch 2|, and a conductor 221 extending from the other terminal of the control resistance 2|3 to the cooperating stationary contact 23 of the switch 2|.

For the purpose of operating the shafts 33 and 34 the present embodiment comprises a pair of discs 230 and 240 each provided on one face with an integral hub 23| or 24| receiving the adjacent end of the respective shaft 33 or 34, each secured to the respective shaft 33 or 34 by a pin 232 or 242 traversing the hub 23| or 24| and the shaft 33 or 34, each provided in its other face with a central bearing recess 233 or 243 rotatably supporting one end of a relevant drive shaft 234 01'244, and each carrying a pair of studs 235 or 245 rotatably mounting pinions 236 or 246 engaging a cooperating sun gear 231 or 241 fixed to the respective drive shaft 234 or 244, and further a pair of arms 238 and 248 each freelyrotatable on the respective drive shaft 234 or 244 and each carrying a double ring gear 239 or 249 engaging interiorly with the respective pinions 236 or 246 and exteriorly with a common interconnecting gear260.

For the same purpose the present embodiment comprises further a shaft 26| operated by the main motor 205 and provided with a pair of worms 262 and 263 coacting respectively with worm gears 264 and 265 carried by the drive shafts 234 and 244, a shaft 266 driven by the auxiliary motor 206 and provided with a worm 261 cooperatively engaging a worm gear 268 fixed to a jack shaft 269, and a worm 210 carried by the jack shaft 269 and cooperatively engaging a worm wheel 21| fixed to a shaft 212 on which is mounted the interconnecting gear 260 engaged by the external teeth of the ring gears 239 and 240.

With the above arrangement, the'pitch and direction of the worms and threads, and the number of teeth in the gear and pinions, are selected so that upon operation of the main motor 205 at a proper speed and in the proper direction, regardless of the auxiliary motor 206, the electrodes and I2 will be fed at a combined rate numeri-- cally equal to the combined rate at which they" are consumed at the current at which the lampis desired to operate, and on the other hand, that; upon operation of the auxiliary motor 206 with the main motor 205 stationary, the positive elec-' trode I would be retracted, and the negative elec trode l2 would be advanced, and both at the samerate, thus effecting no change in the spacing of. the electrodes, but resulting in shifting the location of the arc.

Accordingly, in the present embodiment, each of the motors 205 and 206 being connected to 1'0- tate in the proper direction, first the main motor adjusting rheostat 2 is set to effect operation of the main motor 205 at the speed to feed the electrodes 1 and I2 at the combined rate numerically equal to the combined rate at which they are consumed at the current at which the lamp is desired to operate, and then the auxiliary motor adjusting rheostat 2|2 is set to effect operation of the auxiliary motor 206 at a speed slightly greater than the speed at which the ratio of the rate of feed of the positive electrode H to the rate of feed of the negative electrode |2 would be exactly equal to the ratio at which the respective electrodes are consumed.

Thus the crater M of the positive electrode I! will begin to recede, but before it has proceeded materially, light from the crater M will become directed by the lens 26 through the opening 25 in the switch housing 24, onto the bi-metallic arm 22 of the switch 2|, and will cause the arm 22 to come into engagement with the cooperating stationary contact 23, thereby closing the switch 2| and shunting the control resistor 2 3, resulting in decreasing the speed of the auxiliary motor 206, thus increasing the rate of feed of the positive electrode H and equally decreasing the rate of feed of the negative electrode I2.

The control resistance 2|3 being of proper value, thereupon the rate of feed of the positi-veelectrode will be slightly greater, and the rate of feed of the negative electrode |2 equally less, than the rates at which the respective elecwhen trodes' are being consumed, and thi'is" the crater I f'will become restored to 7 its previous position, whereupon the lens'26will no l nger direct light fromthe crater I4 through'the" opening 24,"the

arr'ri"'22' W'ill' wifihdraw from the, Cooperating S133? canary contact" 23, theshil nt will be, removed frorn'the controlrsistor 2I3, an'dithe meena:

mati'cally"maintain both "proper quality of the arc and proper optical relation, 7 v In the embodiment of Figure 3 the positive electrode I I is connected by a main positive conductor 30 i extending iro'm the positive electrode clamp 21 to a positive connection terminal 302,

the negative electrode I2 is connected by a main negative conductor 303 extending from the negative electrode clamp 28 to, a negative connection terminal 354, and suitable rotation or the shafts 33 and 34 and thus suitable reciprocationof the positive and-negative electrodes II and I2, are effected by first and second shunt-connected direct- current motors 305 and 306 having their armatures 307 and 308 connected directly across the main positive and negative conductors 30I and 303 and their fields 309 and 3H] connected acrossthe mainconductors 30I and'303 in series respectively with a first motor adjusting rheostat -H! and a control'resistance 3I3 arranged to be shunted by the switch 2|, and with a second motor adjusting rheostat 3I2.

As herein shown the above electrical connections are accomplished'by a conductor 320 extending fromthe'main positive conductor 30I to one'terminal of the' first motor armature 301 and one terminal of the control resistance 3I3, a conductor 32I extending from the other terminal of the control resistance 3I3 to one terminal of t'hefirst motor adjusting 'rheostat, 3H, a conductor322 'exte'nding from the other terminal of-the first 'motor'adjusting 'rheos'tat 3| I" to one terminalof the first motor field 309,'a conductor" 323 extending from the other 'termihalbf the one terminal of the second'motor adjusting rheostat 3I-2, a conductor 325 extending from the other terminal of the second motor adjusting rheostat 3I2 to one terminal of the second motor field 3I0, a conductor 326 extending from the other terminal of the second motor'armature 300 and the other terminal of the second motor field 3I0, to the main negative conductor 303;

a conductor 32'! extending from the conductor 320 to the cooperating stationary contact 23 of the switch 2|, and a conductor 32'8 extending Iromthe bi-metallic arm 22 of the switch" 2| to the conductor 32I.

For the purpose'of operating the negative eleck trade shaft 34 the present embodiment comprises a shaft 330 operated by the first motor 305- and provided with a worm 33I engaged with a worm wheel 332 carried by a jack shaft 333, an'd a worm 334 carried by the jack shaft 333 and engaged with a worm wheel 335 carried'by a sleeve 33'6'secured to the shaft 34 in any suitable manner," as by a pin 33'! traversing the sleeve "336'and the shaft 34.

with the sun gear 341' and with the internalteetli of a duplex 'ring gear 35f carried by a journaled on the sleeve 340, a'nda gear 353 rnesh ing with the external teeth of the rin'g'gear 35I,

provided with a hub 354, and secured to the shaft.

33b means of a pi'n 355 traversing the hub35l andl.the shaft 34. I 1

v With the above arrangement the. number of,

teeth in thevarious' gears and'pinions' interconmeeting the sleeves 336 and 346, [is selected so thatjupon rotation of the sleeve 335 in the die I rection to advance the negative electrode I2, but withthe sleeve 346 stationary, the positive electrode II would be retracted at the same rate at which the negative electrode I2 is advanced.

Accordingly, in the present embodiment, each of the motors 305 and 303 being connectedto rotate inthe proper direction, first the first motor adjusting'rheostat M I. is set to effect operation of the first motor 335 at a speed slightly greater that the speed necessary to feed the negative electrode I2 at the rate at which it will be .consurned at the current at which the lamp is desired to operate, and thenthe second motor adjusting rheostat, 3I2 is set to efi'ectoperation of the second motor 303 at the speed proper to feed the positive electrode I! at such rate thatth combined rates of feed of the two electrodes II and [2 will be numerically equal to thecornbined rates'at which the electrodes II and I2 will be consumed at the designated current.

Thusjthe two electrodes will automatically be terial extent, light from 'thecrater I 4 will become 1 cirectcd by the lens 23 through the opening 25' in thefswitch housing 24, 'onto the lei-metallic arm 22 "of the switch it, and will cause. the arm 22 to come into engagement with the cooperating stationary contact 23, thereby closing the switch 2i and shunting the control resistor 3L3, re-

sultingin decreasing the speedof the first motor A 305 and thereby decreasing the rate of feed o'f the negative electrode I2 and correspondingly. in,

creasing the rate of feed of the positive electrode I I. I I

The control resistance 3i3 being of proper. value, thereupon the rate of feed of thepositive I electrode I I will be slightly greater, and the rate of feed of the negative electrode I2, equally less, than the respective rates at which they are to be consumed, and thus the crater I I will become restored to its previous -position, whereupon the lens 2-6 will no longer direct light from the crater I4 through the openin -24, the arm 22 will withdraw from the stationary contact 23,, the, shunt will beremoved from the. control resistance, 313, and the mechanism will be restored to its previous condition.

Accordingly the embodiment of Figure 3' also operates automatically to maintain both proper total feed of the electrodes and properjlocation of the arc, and therefore to automatically maintain both proper quality of the :arc and proper optical relation. I

In the embodiment of Figure 4the positive electrode 11 is connected by ar-main positive conductor 401 extending from the positive electrode clamp 2'1 to a positive connection terminal 4112, the negative electrode '12 is connected by aimain negative conductor 403 extending from the negative electrode clamp 28 to a negative connection terminal 404, rotation of the shaft 33, and thus reciprocation of the positive electrode .11., are effected by a shunt-connected direct-currentmotor 410 comprising a rotaryarmature 411 and a stationary field 412 and having its armature 411 connected to the shaft 33 by a transmission indicated at 413 and shown as including a suitable speed reduction mechanism 414, and :rotati-on'of the shaft 34, and thus reciprocation of .the negative electrode 12, are effected by a shunt-connected direct-current motor 420 comprising a rotary armature 421 and a stationary field 422 and having its armature 421 connected .to the shaft 34 by a transmission indicated at 423 and shown as including a suitable speed reduction mechanism 424.

In this embodiment each of the motor armatures 411 and 421 is connected directly between the main positive and negative conductors 401 and 403, each of the motor fields 412 and 422 is connected between the main conductors 401 and 403 in series with a suitable fixed resistor 415 or 425 and a control rheostat415 or 426, and each of the rheostats 416 or 426 comprises a main winding 41! or 421, a compensating winding, 418 or 428 connected to the circuit at the same end at which the respective main winding 41''! or 42'! is connected, and a bridge 419 or 429 effecting electrical connection between the two windings of the respective rheostat 415 or 426 and adjustable longitudinally of the windings thus to adjust the portions of the windings included in. circuit.

As herein shown the above electrical connecti-ons are accomplished by a conductor 4311 extending from the main positive conductor 401 to one terminal of the first motor armature 4| I, one terminal of the first motor field 4 I 2, one terminal of the second motor armature 421, and one terminal of the second motor field 422, a conductor 431 extending from the other terminal of the first motor'field 412 to the one end .of the first rheostat main winding 411, a' conductor 432- extending from the corresponding end of the first rheostat compensating winding 418 to'one terminalof the first fixed resistor 415, a conductor 433 extending from the other terminal of the second motor field 422 to the one end of the second'rheo- .stat main winding 421, a conductor 434 extending from the corresponding end of the second rheostat compensating winding 428 to one terrninal of the second fixed resistor 425, and a conductor 435 extending from the other terminal of the first motor armature 41 1, the other terminal of the first fixed resistor 415, the other terminal of the second motor armature 421, and the other terminal of the second fixed resistor 425, to the main negative conductor 403.

However, the present embodiment comprises also an electromagnetic switch 440- including an actuating coil 441 responsive to the condition of {the control switch 21 and to that purpose connected between the main positive and negative conductors 401 and 403 in series with the switch 21, and a switch arm 442 responsive to the condition of the coil 441, arranged to be in engagement with a normal contact 443 when the coil 441 is not energized and to be brought into engagement with an alternate contact 444 when the coil 441 is energized, and connected in the one position to shunt the first fixed resistor 415 and the in-circuit portion of the first rheostat compensating winding 418, and in the other position to shunt the second fixed resistor 425 and the in-circuit portion of the second rheostat compensating winding 428.

As herein shown the foregoing connections are accomplished by a conductor 450 extending from the branch positive conductor 43!] to one terminal of the coil 441, a conductor 451 extending from the other terminal of the coil 441 to the stationary contact 23 of the control switch 21, a conductor 452 extending from the bi-metallic arm 22 of the switch 21 to the main negative conductor 443, a conductor 453 extending from the first rheostat bridge 419 to the normal contact 443, a conductor 454 extending from the second rheostat bridge 429 to the alternate contact 444, and a conductor 455 extending from the switch arm 442 to the branch negative conductor 435.

With the described arrangement the first rheostat 416 is set so that with the switch 442 in the position shown, the first motor 414 will operate at a speed which taken in conjunction with the ratio of the first speed reducing mechanism 414, will feed the positive electrode 1 1 at a rate slightly less than the rate at which that electrode will be consumed at the current at which the lamp is desired to operate, and then the second rheostat 426 is set so that with the switch 442 in the position shown, the second motor 420 will operate at that speed which taken in conjunction with the ratio or" the second speed reducing mechanism 424, will feed the negative electrode 12 at a rate such that the combined rates of feed of the two electrodes 11 and 12 will be numerically equal to the combined rates at which the two electrodes 11 and i2 will be consumed at the indicated current.

Thus the two electrodes will automatically .be maintained at the correct spacing, and the qual ity of the arc will be maintained, but the arc will begin to shift in the direction of advance of the negative electrode, and the crater 14 will begin to recede from the proper position relative to the remainder of the optical system.

However, before this has proceeded to any material extent, the light from the crater 14 will become directed by the lens 25 through the opening 25 in the switch housing 24, onto the bi-metallic arm 22 of the switch 21, and will cause the arm 22 to come into engagement with the cooperating contact 23, thereby closing the switch'21. and completing the circuit through the coil 441 of the electro-magnetic switch 440, thus shifting: the

switch arm 442 from its position in engagement.

with the normal contact 443 to the position in engagement with the alternate contact 444,'re-.', moving the shunt from the first fixed resistor 4| 5 and the in-circuit portion of the first rheostat compensating winding 418 and imposin a shunt on the second fixed resistor 425 andthe in-circuit portion of the second rheostat compensating winding428. I 4

As will be understood, this will result in decreasing the current in the field 412 of the first motor 411) and increasing the current in the field 422 of the second motor 523, thus increasing the speed of the first motor 5! and consequently the rate of feed of the positive electrode II, and decreasing the speed of the second motor 420 and consequently the rate of feed of the negative electrode !2.

Under these circumstances, the fixed resistances M and 425 and compensating resistances M8 and 42B are selected so that in any position of the resistor bridges M3 and 425, the change in speed of the first motor Mil will be sufficient to cause the positive electrode to be fed at a rate greater than the rate at which it is being con sumed, thus gradually to restore it to its desired position, and also that the concurrent reduction in the rate of feed of the negative electrode !2 will be numerically equal to the increase in the rate of feed of the positive electrode ll, thereby to continue to maintain the proper gap between the electrodes I! and !2 and thus the proper quality of the are.

As will also be understood, when the crater !4 has become restored to its desired position, the lens'26 will no longer direct light from the crater I4 through the opening 25, the arm 22 will withdraw from the stationary contact 23, the coil 44! of the electro-magnetic switch Mil will no longer be energized, and the mechanism will be restored to its previous condition.

Accordingly the embodiment of Figure 4 also operates to automatically maintain both proper quality of the arc and proper position of the crater !4 of the positive electrode H, and thus to automatically maintain both proper quality of the arc and proper position.

In the embodiment of Figure 5 the positive and negative electrodes I and 12 are carried by metal clamps 50! and 502 forming parts of positive and negative electrode carriers 503 and 504 reciprocably mounted on a pair of supporting rods 505 extending through openings 500 in the carriers 503 and 504, are connected by main positive and negative conductors 50'! and 508 extending from the respective clamps 5e! and 502 to a positive connection terminal 559 and a negative connection terminal 5!0, and are fed by mechanism comprising a shaft 5!! rotatably mounted on the positive electrode carrier 503, a shaft 5l2 rotatably mounted on the negative electrode carrier 504, large worm gears 5!3 and 5M fixed to the shafts 5!! and 512, a duplicate small worm gears 5!5 and 516 connected to the shafts 5!! and 5!2 through suitable friction clutches not shown, a main shaft 520 comprising a screwthreaded section 52! cooperatively engaging the positive carrier gear 5!3 and a reversely screwthreaded section 522 cooperatively engaging the negative carrier gear 5M, and an auxiliary shaft 530 comprising duplicate screw-threaded sections 53! and 532 cooperatively engaging the duplicate ears 5!5 and 5!6.

Under these circumstances the shafts 520 and 530 are intended to rotate in the directions i11- dioated by the arrows appearing on the respective shafts, and rotation of the shaft 525 in the indicated direction will rotate the gears 5!3 and 5!4 in the directions indicated by the arrows appearing on the respective gears, and in the present embodiment such rotation of the shaft 520 is accomplished by a Worm gear 523 carried by the shaft 520 and operated by a coacting worm 524 fixed to a jack shaft 525, and a worm gear 520 carried by the jack shaft 525 and operated by a coacting worm 52'! provided on the shaft 528 of the armature 54! of a main shunt-connected direct-current motor 540, and similarly rotation of the auxiliary shaft 535 is accomplished bya worm gear 533 carried by the shaft 530 and operated by a ooacting worm 534 fixed to a jack shaft 535, and a worm gear 536 carried by the jack shaft 535 and operated by a coacting worm 53! provided on the shaft 538 of the armature 55.! of an auxiliary shunt-connected direct-current motor 550.

According to the present embodiment the main motor 540 has its armature 54! connected across the main positive and negative conductors 50'. and 508 and its field 542 connected across these conductors 50,! and 508 in series with a main motor adjusting rheostat 543, the auxiliary motor 550 has its armature 55! connected across the main conductors 50! and 508 and its field 552 connected across these conductors 531 and 503 in series with an auxiliary motor adjusting rheostat x553 anda control resistor 554, and the switch 2| is connected to shunt the control resistor 554.

As herein shown the above connections are acoomplishedsby a conductor 545 extending from themain positive conductor 50? to one terminal of the main motor armature 54! and one terminal of the main motor field 542, a conductor 54-5 extending from the other terminal of the main motor field 542 to one terminal of the main motor adjusting rheostat 543, a conductor 54'! extending from the other terminal of the main motor armature 54! and the other terminal of the main motor adjusting rheostat 543, to the main negative conductor 508, a conductor 555 extending from the, main positive conductor 55'. to one terminal of the auxiliary motor armature 55! and one terminal of the control resistor 554, a conductor 556 extending from the other terminal of the auxiliary motor armature 55! to the main negative conductor 508, a conductor 55"! extending from the other terminal of the control resistor 554 toone terminal of the auxiliary motor adjusting rheostat 553, a conductor 550 extending from the other terminal of the auxiliary motor adjusting rheostat 553 to one terminal of the auxiliary motor field 552, a conductor 55% extending from the other terminal of the auxiliary motor field 552 to the main negative conductor 508, and conductors 560 and 55! extending from the terminals of the control resistor 554 to the bi-metallic arm 22 and stationary contact 23 of the switch 2!.

With the foregoing the pitch of the positive carrier thread 52! and the pitch of the negative carrier thread 522 are such that the ratio to the pitch of the negative carrier thread 522 is somewhat greater than the highest ratio of the rates at which the respective electrodes and !2 will be consumed at any current at which the lamp is constructed to be operated.

Under this condition, if the shafts 520 and 530 are rotated in the indicated directions and at exactly the speeds proportional to the respective gears 52!5!3 and 53!5!5, obviously each of the shafts 520 and 530 would operate to rotate the positive carrier shaft 5!! at the same speed and in the same direction, and merely the positive carrier shaft 5!! would rotate, and the positive carrier 503 would remain stationary. However, in such event the negative carrier 554 would be very rapidly advanced.

On the other hand, if the shaft 530 is rotated at a lesser speed than the above proportionate speed, the positive carrier 503 will be correspondingly advanced, and the rate of advance of the negative carrier 504 will be equally decreased, and thus the speed of rotation of the auxiliary shaft 530 determines the distribution between the electrodes H and I2 of the total feed determined by the speed of rotation of the main shaft 52! Accordingly, the main motor adjusting rheostat 543 is set to eifect rotation of the main motor 540 at that speed at which the combined rates of feed of the positive and negative electrodes H and 12 are numerically equal to the combined rates at which the electrodes H and 12 will be consumed at the current at which the lamp is desired to operate, and then the auxiliary motor rheostat 553 is set to effect rotation of the auxiliary motor 550 at a speed at which the rate of feed of the positive electrode II is slightly less, and the rate of feed of the negative electrode I2 is slightly greater, than the rates at which the respective electrodes II and [2 will be consumed at the indicated current.

Thus the two electrodes H and IE will automatically be maintained at the predetermined spacing, and the quality of the arc will be maintained, but the arc will begin to shift in the direction of advance of the negative electrode, and the crater M will begin to recede from the proper position to coact fully with the remainder of the optical system.

However, before this has proceeded to any material extent, light from the crater M will become directed by the lens 26 through the opening in the switch housing 24. onto the bi-metallic arm 22 of the switch 2 I, and will cause the arm 22 to come into engagement with the cooperating stationary contact 23, thereby closing the switch 2| and shunting the control resistor 554, resulting in decreasing the speed of the auxiliary motor 550 and thereby decreasing the rate of feed of the negative electrode l2 and correspondingly increasing the rate of feed of the positive electrode ll.

The control resistance being of proper value, thereupon the rate of feed of the positive electrode II will be slightly greater, and the rate of feed of the negative electrode l2 equally less, than the respective rates at which they are being consumed, and thus the crater It will become restored to position, whereupon the lens 26 will no longer direct light from the crater Hi through the opening 24, the arm 22 will withdraw from the stationary contact 23, the shunt will be removed from the control resistance 554, and the mechanism will be restored to its previous condition.

Accordingly the embodiment of Figure 5 also operates automatically to maintain both proper total feed or the electrodes and proper location of the arc, and therefore to automatically maintain both proper quality of the arc and proper optical relation.

Therefore each of the described embodiments accomplishes at least the principal object of my invention; On the other hand, each of the described embodiments can be variously changed and modified, also other embodiments maybe substituted, all without departing from the purpose and scope of my invention, and thus my invention is not to be regarded as limited to the present disclosure, but the present disclosure is illustrative only, and I claim as my invention:

1. An arc lamp comprising two electrodes constructed and arranged to function as terminals of an arc, electrically energizable means constructed and arranged to automatically and continuously feed said electrodes at a substantially constant combined rate, and capable of change of the ratio between the respective rates of feed while maintaining the combined rate substantially constant, and means constructed and arranged to control the electrically energizable electrode feeding means to automatically change said electrode feed rate ratio in response to change in position of the arc.

2. An arc lamp comprising two electrodes constructed and arranged to function as terminals: of an arc, electrically energized means con structed and arranged to continuously and auto-- matically feed said electrodes at a substantially constant combined rate, adjustable to change said rate, and capable of change of the ratio between the respective rates of feed of said electrodes while maintaining the combined rate substantially constant, and thermo-responsive means constructed and arranged to control the electrically energized means to automatically change said electrode feed ratio in response to change in position of the arc.

3. An arc lamp comprising two electrodes constructed and arranged to function as terminals of an are, means constructed and arranged to continuously and automatically feed said electrodes at a substantially constant combined rate substantially equal to the rate at which said electrodes will be consumed at the current at which the lamp is desired to be operated, thereby to automatically maintain the quality of the arc, and capable of change of the ratio between the respective rate of feed while maintaining the combined. rate substantially constant, and thermo-responsive means constructed and arranged to control the electrode feedin means to automatically change said ratio in response to change in position. of the arc.

a. An arc lamp comprising two electrodes constructed and arranged to function as terminals of an arc, electrically energized means constructed and arranged to continuously and automatically feed said electrodes at a substantially constant combined rate substantially equal to the rate at which said electrodes will be consumed at the current at which the lamp is desired to be operated, thereby to automatically maintain the quality of the arc, and to normally feed said electrodes at differential rates of a rate ratio different from the rate ratio at which said electrodes will be consumed at such current, and capable of change of said ratio while maintaining the combined rate substantially constant, and thermo-responsive means constructed and arranged to control the electrically energized means to automatically change said electrode feed ratio in response to a relative change in position of the arc and to a ratio different from the ratio at which said electrodesv will be consumed at such current but departing in the inverse direction.

I 5. An arc lamp comprising two electrodes constructed and arranged to function as terminals of an arc, electricallyenergized means constructed and arrangedto continuously and automatically feed said electrodes at a substantially constant combined rate, adjustable to'set said rate to be substantially equal to the rate at which said electrodes will be consumed at the current at which the lamp is desired to be operated, thereby to automatically maintain the quality of the arc, means for changing the ratio between the respective rates of feed of the individual electrodes while maintaining the combined rate substantially constant, and means constructed and arranged to control the electrically energized means to automatically change said electrode feed ratio in response to change in position of the are.

'6. An arc lamp comprising two electrodes con structed and arranged to function as terminals of an are, means including a pair of electrically energized motors constructed and arranged to continuously and automatically feed said electrodes at a sub-stantially constant combined rat-e, adjustable to change said rate, and capable of change of the ratio between the respective rates of feed while maintaining the combined rate substantially constant, and circuit controlling means for said motors constructed and arranged to automatically change said electrode feed ratio in response to change in position of the arc and .thereby to automatically maintain the are substantially at a given position.

7. An arc lamp comprising two electrodes constructed and arranged to function as terminals of an arc, means constructed arranged to continuously and automatically feed said electrodes at a substantially constant combined rate substantially equal to the rate at which said electrodes will be consumed at the current at which the lamp is desired to be operated, thereby to automatically maintain the quality of the are, and capable of change of the ratio between the respective rates of feed While maintaining the combined rate substantially constant, and means constructed and arranged to control said electrode feeding means to automatically change said electrode feed rate ratio in response to change in position of the arc and thereby to automatically maintain the are substantially at a given position.

8. An are lamp comprising two electrodes constructed and arranged to function as terminals of an arc, means constructed and arranged to continuously and automatically feed said electrodes at-a substantially constant combined rate, and thermo-responsive means constructed and arranged to control said electrode feeding means to automatically maintain the are substantially at a given position.

9. An arc lamp comprising two electrodes constructed and arranged to function as terminals of an are, means including a pair of electrically energized motors constructed and arranged to continuously and automatically feed said elec trodes at a substantially constant combined rate r;

substantially equal to the combined rate at which said electrodes will be consumed at the current at which said lamp is desired to be operated, thereby to automatically maintain the quality of the arc, and means intercalated in a circuit of one 1 of said motors constructed and arranged to automatically maintain the are substantially at a given relative position.

10. An arc lamp comprising two electrodes constructed and arranged to function as terminals of an are, means constructed and arranged to continuously and automatically feed said electrodes at a substantially constant combined rate, and adjustable to set said rate to be substantially equal to the combined rate at which said electrodes will be consumed at the current at which said lamp is desired to be operated, thereby to automatically maintain the quality of the arc, and means responsive to a change in relative position of the are constructed and arranged to control said electrode feeding means to automatically return the arc to its normal position.

11. An arc lamp to operate on direct current, comprising a positive electrode and a negative electrode constructed and arranged to form the terminals of an arc, means constructed and arranged to continuously and automatically feed said electrodes at a substantially constant combined rate, and capable of change of the ratio between the respective rates of feed While maintaining the combined rate substantially constant, and thermo-responsive means constructed and arranged to automatically change said electrode feed rate ratio in response to change in position of the tip of said positive electrode.

12. An arc lamp to operate on direct current, comprising a positive electrode and a negative electrode constructed and arranged to form the terminals of an are, electrically energized means constructed and arranged to continuously and automatically feed said electrodes at a substantially constant combined rate, and capable of change of the ratio between the respective rates of feed while maintaining the combined rate substantially constant, and means associated with said electrically energized means constructed and arranged to automatically change said ratio responsive to change in the relative position of the tip of said positive electrode and thereby to automatically maintain the tip of said positive electrode substantially at a given location.

13. An arc lamp comprising a positive electrode and a negative electrode constructed and arranged to form the terminals of an are; means individual to each electrode for continuously feeding said electrodes at a substantially constant combined rate; means for varying the feed. rate of the individual electrode feeding means without affecting the combined rate of feed of the electrodes, and thermo-responsive means dependent for operation upon the relative position of the are for controlling the feed rate of the individual electrode feeding means.

14. An arc lamp including two electrodes constructed and arranged to function as terminals of an are; means individual to each electrode for continuously feeding the electrodes to are forming position; said feeding means coacting to feed said electrodes at a substantially constant combined rate; means for automatically changing the feed rate ratio of said individual electrode feeding means without affecting the constant combined rate, and thermo-responsive means controlled by the relative position of the arc for changing the feed rate ratio of the electrode feeding means.

ARTHUR J. HATCH.

REFERENCES CITED The following references are of record in the file of this patent:

. UNITED STATES PATENTS Number Name Date 1,132,776 Hobbs Mar. 23, 1915 1,313,666 Beck Aug. 19, 1919 2,117,886 Jacobi et al. May 17, 1938 2,160,490 Strong May 30, 1939 2,162,524 Brace et a1 June 13, 1939 2,184,765 Farley et a1 Dec. 26, 1939 2,469,664 Murch May 10, 1949

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