US1623848A - Arc lamp - Google Patents

Description

2 Sheets-Sheet l E. J. MURPHY ARC LAMP Filed April 6 April 5 1927 His Attorney April 5 1927. 1,623,848

E. J. MURPHY ARC LAMP Filed April e, 1925 2 sheets-sheet 2 EciwLn 4]. murpily hay MJT@ Patented Apr. 5, 19,27. UNITED STATESv PATENT OFFICE.)

EDWIN J. MURPHY, F SCHENECTADY, NEW YORK, ASBIGNOR T0 GENERAL ELETBIC l l COMPANY, A CORPORATION 0F NEW YORK.

Anc uur.

atpueataml ma Aprn e, 1925. serial no. 20,021.

' My invention relates to arc lamps, and in particular to the feeding mechanism for such lamps. Among the objects of my 1nvention are the following: To provide a.

feeding mechanism by means of which an electrode may be fed by two independent mechanisms at two different rates to pro-Y vide a feeding mechanismadapte to feed an electrode by two independent mechm anisms at two different rates, one rate being under electroma netic control so that this feeding rate may e suspended or continued without acceleration; to provide means for feeding an velectrode at two diflb ferent rates, one without acceleration and one intermittent, and electromagnetic means l for controlling the feeding at one rate and electromagnetic means for controlling the feeding. at a different rate; to provide a feedinga mechanism with means for feeding at two differentl rates and with electromagnetic Y means and also with independent mechanical means for controlling one rate of feeding so as to sus end or continue without acceleration this rate of feeding, and to provide other means for increasing the eiciency and serviceability of an arc lamp of they above character.

To the foregoing and other useful ends my invention com rises means hereinafter more fully set fort and `claimed, reference being had to the accompanying drawings in which Figure 1 shows an arc lamp, 1n elevation, comprising my invention; Fig. 3'5 2 is a diagrammatic illustration showing the relation of certain elements of the lamp for the purpose of facilitating an understanding ofv the invention; Fig. 3 shows the cam by means ofl which one of the feeding operations is produced. It also shows a section of the electromagnetically controlled mechanism, and a section of the manuall `controlled mechanism.'b v means of whic the feeding is regulated; E ig. 4 is a bottom view of a section of the device' shown in L Fig. 1, and Fig. 5 is a diagrammatic sketch -showing the relation of the electrodes and of the feed controlling magnets. yReferring more in detail to the drawings, and in particular to Fig. 1, the usual os1- tive electrode 2 passes through the positive head 3, while the usual-negative electrode 4 asses through the negtive head Thls liitter head 5, it will seen, is pivotally '55 mounted to oscillate about the axis 6,*as is well known. The feeding operation of the yproduced through the medium of the shaft 8. 'As is well understood, the object in having the head 5 arranged to osclllate about the axis 6 is to enable the arc to bestruck when the current is turned on. Normally, as is well understood,2 the head 5 is in a. raised position in which position it is intended that the electrodes 2 and 4 should be in contact. When the current is turned on, the head 5 is caused to rotate about the axis 6 so that the electrode 4 leaves the electrode 2 thereby establishing the arc. This operation of the head 5 about the axis 6 is under the control of the rod 9. The normal relative position of the electrodes when the current is turnedo is indicated in Fig. 5`, in which figure the `electrodes 4 and 2 are shown in contact. To turn on the lamp theswitches 10 and 11. areclosed and current will flow through the electrodes 4 and 2 and through the electromagnet 14. The result is that the armature 15 of the magnet is energized, pushing the rod upward to rotate head 5 in place' thereof about the axis 6, thus establishing the arc. Also when the switches 10 and 11 are closed, the motor M l is started,`which motor supplies a. pdwer for operating the feeding mechanism. For example, the motor 'M is provided with a shaft having a worm gear 16 which meshes with the worm wheel 17 thereby rotating the shaft '18 with the result that through the medium of other suitable gears and shafts, the shaft 7 is rotated, thus rotating andfeeding the positive electrode 2. On the shaft 18 there is also provided a cam 19 through the medium of which the negative electrode 4 is fed. Under the control of this cam 19v there is an arm 20 adapted to oscillate about the p in or other suitable bearing 21.A On the forwrd end of the arm 20 there is a pawl.22 adapted to engage with the ratchet wheel 23. A compression spring 24 isprovided for maintainin the dog 22 in engagement with the whee 23. On the opposite end'of the arm 20-there is provided a roller 25. This roller is adapted tobe held agalnst the surface of.r the cam 19 by the spring 26. Therefore, it will be seen thatk if the cam 19 rotates about the axis of the shaft 18 the arm 20 is caused to oscillate with the result direction indicated by the arrow.

It will be observed that -behind the roller 25 there is provided a pin 27. In proximity to this pin and in working relation thereto there-is provided a spring 28. This spring is under the control of any suitable device such as the thumb screw 29. Through the medium of this screw 29 it is 4possible to iiex the spring 28 as indicated in Fig. 3 causing it to serve as a limiting stop for the arm 20. It will be seen, therefore, that when the spring 28 is raised as in Fig. 3 the advance produced in the shaft 8 at the stroke of the dog 22 is shortened inasmuch as the pin 27 permits the arm 2O to approach toward the cam 19 only a limited distance.

In connection with this feeding mechanism for the negative electrode, I provide an electromagnetic device involving the electromagnet 30. This electromagnet, as ,in-

dicated in Fig. 5, is connected across the.

electrodes 2 and 4. The result is that the magnetic intensity of the field of this inagnet depends upon the condition of the arc and upon the Ydistance separating the electrodes 2 and 4. In this connection it will be observed that the cam 19 is provided with a pin 31. In the path of rotation of this pin there is 'a stem 32 mounted on the dog 33 which is found on the armature 34 of the magnet 30. Normally the armature 34 is held away from the pole .piece by the spring 35. With the construction described,

even if the magnet 3() is deenergized, the armature 34 is pressed against the pole piece once in each revolution of the cam 19. However, should the magnet 30 be energized then when the armature '34 is pressed against the pole piece by the action of the pin 31, the armature will be held there against the tension of the spring 35 and therefore the dog 33 will be held out of the path of the cate 36 (see Fig. 4). As long as this magnet continues to hold the armature 34, the cam will continue to operate the arm 20 and the feeding operationvof the negative electrode continues. However, if the electrodes 2 and 4 are brought into such proximity that the voltages across the electrodes is lowered below a certain point, the spring 35 will withdraw the armature 34 from the core with the result that the dog 33 will latch and hold the catch 36, thereby preventing and siispending the feeding operation. It will be un erstood that under-these conditions the pin 31 at each revolution will press the armature 34 against the core in opposition to the tension of the spring 35. But the pin and the high point in the cam 19 and the roller 25 are so adjusted that the pin 31 will release the ar mature 34 before the catch 36 has had time to advance andescape the dog 33. However, at the moment that the magnetic pull of the electromagnet 30 increases to such au extent as to be able to hold the armature 34 then even after the pin 31 leaves the stem 32 the armature 34 will be held and the arm 2O will be left under the control of the cam 19 so that the feeding operation will proceed.

- It sometimes of the negative electrode or possibly the tip end of the positive electrode is broken and that as a result the electrodes 2 and 4 are not i contact when the circuit is initially Aclosed through the lamp. The result is that the electromagnet 14 does not energize and the arc is not struck and cannot be struck until the feeding operation produced by the motor M advances sufficiently to bring thel two electrodes into contact. At this mo ment, of course, the magnet 14 energizeswith the result that the arc' is formed as alreadyI described:

If the only feeding mechanism provided -were that already described under the control of the c m 19 and of the electromagnct /30 the feeding operation would be compara- "tively slow and considerable time might sometimes elapse before the "arc would be started vafter the circuit is closed at the switches 10 and 11. In order to avoid this delay, which in manyv instances is very undesirable, I provide means for rapidly feeding the negative electrode in the eventvthat the magnet 14 is not energized while the switches 10 and 11 are closed.

As already pointed out the striking operation is under the control of the magnet 14 through the medium of the armafure l5 and of the ar1n`9. By Vreferring to Fig. 2, it will be seen that I provide on the shaft 18 a gear 37, which is feathered to slide on the shaft 18, but which cannot rotate without rotating the shaft 18. In operative relation with the gear 37 and on the shaft 8 upon which the ratchet wheel 23 is mounted, is a second lgear 39 which is secured to the shaft 8. By this arrangement, whenever the .gear 39 is rotated the feeding shaft 8 is also rotated. It will be seen that the gear 37 is under the control of the bifurcated arm 40, the prongs )of which are in mesh with a groove on the hub of th'egear 37. This arm 40 is 4so locatedthat the rod 9 passes through a hole in the arm 40. The arm 40, it will be further seen,is pivoted to oscillate about the pin 41. Between the arm 40 and a section 42 o-f the frame of the lamp, I provide a compression spring 43 which tends normally to depress the arm 40 and. also the armature 15 inasmuch as I provide a collar on the underside of the arm 40 secured` to the shaft 9.

With the arrangement described when the magnet 14 is deenergized the gear 37 is depressed bythe spring 43 into engagement with the gear 39. Therefore, if the switches happens that the tipA end l. velectrode 2 or 4 is broken so that the electrodes are not in contact, the motor M will begin to operate but the electromagnet 14 cannot ener ize. The result is that the motor M wi l drive .the shaft '18 and therefore the gears 37 and 39, andconsequently the feed shaft 8, thereby producing a very rapid feed which will immediately bring -the two electrodes into contact. As soon as the circuit is closed between the electrodes, the

`magnet 14 energizes striking the arcand disconnecting the gears 37 and 39 and thus terminates the rapid feed. The rapid feed if desired may be made about lifty or sixty times faster more or less than the regular average feed while the arc is burning. This rate of feed gives the electromagnet 14 `suiicient time to act to disconnect the direct feed and leave the electrodes to the action of the regulator feed.

It will be seen, therefore, that I provide' an arc lamp lwith, a driving motor which rotates the positive electrode and the nega- '.tive electrode, andfwhich provides power for feeding both the positive and the negative electrodes. In'addition I provide means for uickly striking the arc in the event that t e two electrodes are normally in contact at the start. As described the negative elecv 'trode is fed forward by means of a mechanism driven by a ratchet Wheel, the ratchet wheel in the preferred construction shown being connected to the feeding mechanism and being provided with teethengaged'by a pawl, which pawl is continuously-reciprocated by means of a cam, which cam is continuously driven by the driving motor of the lamp. This ratchet is adapted to propel the electrode forward-at aspeed considerably greater than. the speed of consumption..v Y

l This'lamp is made automatic by the provi- -sion of the `electromagnet 30, which is connected across the arc. This magnet is adapted to attract its'armature, whlch armature when held in the attracted position will l .allow the ratchet pawl to engage 'the ratchet wheel and. thus feed the negative electrode. When the volta acrossthe arc falls to the proper value, t e armature of the magnet 30 will` not beheld by the electromagnet and thus the lamp will not feed'. In order that the amount of work performed by the electromagnet 30 may be reduced to a minimum,

lthe .cam 19 is provided which regularly forces the armature against the pole piece and ifthe voltage across the regulatin coil 30 is normal the magnety cannot hol the armature. On the other hand, if the voltage is above normal value Jthe armature will be held and the lamp will roceed to feed.

, In order to regulate t e voltage at which I the lamp should operate the tension of the spring 35 is controlled by means of an ladjustable screw 44, which screw supported by any stationary element which may bea until an opportunity presents itself for restoring the electromagnet control. It will be seen also that by the provision of the gears 37 and 39 the high speed feed takes place regardless of the stepy-step feed under the control of the magnet 30. l.

It will be seen, therefore, that one form of the invention comprises afeed for the negative electrode and means such as the gears 37 and 39 for connecting the feed to the driving element, such as the motor M. The invention in one form also contemplates independent means such as the ratchet and gear mechanism 22 and 23 under the control of the cam 19 for operating the feed at a rate substantially different fromthat obtained through the medium of the gears 37 and 39. It will also be seen that either of the means for driving the feed is under the control of electromagnetic means -in order that either means may/be'thrown into or out of operative condition. One of the electromagnetic means, of course, com rises the electromagnet 14Vand the other e ectromagnet 30.

In Fig. 5 the magnet 30 is shown in series with a resistance 46. This resistance may be varied, the object of the resistance being to allow the minimum amount of current to pass throu h the magnet 30 which will insure its e ective operation.

Referring to Fig. 3 it will be seen that when the spring 28 is in the position in dicated in said figure this spring serves as a restricting element, not only to the memberv M20, but also to the armature 34 and, therefore, to the-dog 33, through the medium of the pin 45, which depends from the dog 33. Therefore, when the spring is in the position shown in Fig. 3, the dog 33 is rendered ineffective with reference to the notch 36 and,

therefore, even though the magnet 3() be deenergized the feeding operation under the control of the cam 19 will continue. It willvbe seen, however, thatthe stroke of the element 20 under the conditions shown in' Fig. 3ds shorter than under the conditions much as in view of the disclosure variations may readily be made without departing from the spirit of my invention or from the scope of the claims contained herein.

What I claim as new and desire to secure by Letters Patent of the United States, is

l. In an arc lamp an electrode feed mechanism, a driving element, means interposed between the driving element and the feed whereby the feed is operated by the drive at a rapid rate until the electrodes are brought into contact, and means comprising the electrodes of the lamp for causing the termination of said rapid feed when the electrodes come into contact, and independent means interposed between the driving element and the feed whereby the feed is operated by the drive at a slow rate, said independent means comprising mechanical' elements to render the feeding operation inermittent. A

2. In an arc lamp an electrode feed mechanism, a driving element, means interposed between the driving element and the feed mechanism whereby the feed may be operated by said driving element, an electromagnetic device, said means under the control of said device whereby the feeding operation may be regulaed, said device comprising an armature through the medium of which said control is exercised sometimes by the magnet holding the armature against'the pole piece and sometimes by the magnet releasing the armature, and means independent of the magnet for periodically forcing the armature against the pole piece, and means for rendering the control of said feed through said armature ineffective, and at the same time maintaining the said interposed means effective whereby the feeding operation may be continued without interruption by said armature.

3. In an arc lamp an electrode feed mechanism, a driving element, means interposed between the driving element and the feed mechanism whereby the feed may be oper-v ated by said driving element, an electromagnetic devi( e, said means under the control of said device whereby the feeding operation may be regulated, said device comprising an armature through the medium of which said control is exercised by the magnet holding the armature against the pole piece or by releasing the armature, and means independent of the magnet for periodically pressing the armature against the po-le piece and withdrawing it therefrom.

4. In an arc iamp an electrode feed mechanism, a driving element, means interposed between the driving element and the feed mechanism whereby the feed may be operated by said driving element, an electromagnetic device, said means under the control of said device whereby the feeding operation may be regulated. said device comprising an armature throughthe medium of which said control is exercised sometimes by the magnet holding the armature against the pole piece and sometimes by releasing the armature, and means independent o-f the magnet for causing the armature to periodically advance against the pole piece.

5. In an are lamp having a pair of electrodes, a feed mechanism for one of the electrodes of the lamp, a driving element for said feed, means for driving said feed from the.

said driving element and independent means for driving said feed from the same driving element, and electromagnetic means adapted to be energized from a source of potential for throwing said independent means into operative condition whereby the feeding operation of the electrode through said independent means may be carried on, said electromagnetic means adapted also, when the voltage at said source drops below a certain point, to become deenergized sufficiently for throwing sai-d independent means out of operative condition, whereby the feeding of tue elecrode through said independent means may be terminated.

6. In`an arc lamp having a pair of electrodes, a feed mechanism for one of the electrodes of the lamp, a driving element for said feed,` means for driving said feed from the said driving element and independent means for driving said feed from the same driving element, an electromagnetic means adapted to be energized from a source of potential for throwing said independent means into operative condition whereby the feeding operation of the electrode through said independent means may be carried on, said electromagnetic means adapted also, when the voltage at said source drops below a (-er'ain point to become deenergized sufficiently for throwing said independent means out -o-f operative condition, whereby the feeding of the electrode through said independent means may be terminated, said electromagnetic means comprising an adjustable element for varying the range of acion of said electromagnetic means responsive to the variation in said voltage.

l In an arc lamp havinga pair of electrodes, a feed mechanism for one of the electrodes of the lamp, a. driving element for said feed, meansfor driving said feed from the said driving element and independent means for driving said feed from the same driving element, an electromagnetic means adapted to be energized from a source of potential for throwing said independent means into operative condition whereby the feeding operation of the electrode through said independent means'may be carried on, said electromagnetic means adapted also when the voltage at said source drops below a certain point, to become deenergized sufficiently for throwing said independent means out of.

operative condition, whereby the feeding of thel electrode through said independent means may be terminated, and means for preventing the electromagnetic means, When deenergized, from throwing said independent means out of operative engagement whereby the feeding operation` of the electrede may persist even though lthe electromagnetic nieans be deenergized.

8. I an arc lamp', a fast feed mechanism, a slm' feed mechanism,` an are drawing mechanism, and an electromagnet connected to be energized when current is. flowing through the .electro-des for throwing outqthe fast feed and for drawing ,the fare.

'9. In an arc lamp, a pair of electrodes for maintaining the arc between them, an electroinagnet connected to be energized when a flow of current is established through the electrodes, a feed mechanism for feeding one of said electrodes fast and another for feeding the san'ieelectrodes slowly, a motor for operating said feeds, an arc drawingzmechanism separate fro'in'the feed for-'separating one of the electrodes from the other to draw' the arc, the fast feed and the arc drawing mechanism being under the control of said electromagnet.

10. In an are lamp, a pair of electrodes for maintaining an arcbetween them, an electroinagnet connected to be energized when current is flowing through the electrodes, a feed mechanism for feeding one of said electrodes fast and another for feeding the same electrode slowly, a motor for operating said feeds, an are drawing mechanism separate from the feed for separating one of the electrodes from the other to draw the arc whereby when the. lamp is connected to a source of current while the electrodes are separate both feeds are broughtinto opera- 11. In an are lamp, an eDectrode feed.

mechanism, a driving element, means interposed between tlie driving element and the feed mechanism 'whereby the feed may be loperated by said driving element, an electromagnetic device, said means under the control of said device whereby the feeding operation may be regulated, said device comprising an-aimature through the medium of which saidv control is exercised,v means independent of the magnet foi'vperiodically forcing theC armature against the pole piece., and means for rendering the control of said feed through said armature ineffective and at the saine time maintaining the said interposed means effective whereby the feeding operaticnfmay be continued without interruption by saidl armature.

12. In an arc lamp, an electrode feed mechanism, a driving element, means interposed between the driving element and the feed mechanism whereby the feedmay be operated by saidV driving element, an electromagnetic device, said means under the control of said device whereby the feeding `operation may be regulated, said device comprising an armature through the medium of which said conti-ol is exercised, means'independent of the magnet for causing the armature to periodically advance against the pole 75 piece. i In witness whereof, I have hereunto set my hand this 4th day of April, 1925.

EDWIN J.'MURPHY.

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