US2580137A - Electrode holder for arc lamps - Google Patents

Description

1951 E. R. SUTTLE 2,580,137

ELECTRODE HOLDER F OR ARC LAMPS Filed June 15, 1950 25 v v SQ 26 3O PING/.9 w ej FIG. IO FIG. I l

FIG. l2

- 26 EUGENE R. SUTTLE INVENTOR. 36 BY A TTORNEV Patented Dec. 25, 1951 UNl'PED PATENT OFFICE nnno rn'omnnonnnneroa ARO'LAMPS Eugene (Su'ttle, Wichita, ,Kans..

ap lauded-nine 1:5, 1950, S'rial- No;168C302 This invention? relates-:egenerally to" arc'--lamps, and more particularly to auxiliary eleetrode holders-for such -'lampshol'ders which will make possible the substantially :'complete usenof'iipar It is the chief object of this invention to :provide arc lamp users with an auxiliary extension electrode holder which makes it possible for an arc'lampto' burnboth positive and-negative electiazllyfburned .electro'deswvhich. itfhascipreviousl'y trodes until they are-only'l inch long,- thus 'efbseen necessary tovdi's'card;

As is; well :known 'to those familiarrwithl-this art; the tworcarbonelectrodes r in econventio'nal arcvlamps :are mounted in axial. alignment for movement toward each other as the burning itips disintegrate. To accomplishthis, two opposing carriages are'slidablyilmounted on a -track-or on guidabars sandathe outer end of-eachrel'ectrode is held in auclamp-Jwhichis racpart bfwe'achmar riages The. innerend -'of. -each: electrodev isisupia ported bya'stationary guide, the two glides-serving to. keep the -burning ends of the ael'ectrodes aligned. The guides are located a short distance from the arc,:-and-v as the tips ofr -the electrodes disintegrate; *themoving carriages slide -the -elec-' trodes'th-roughor along these guides Some'of theseguidesare V-shaped, some U-shaped and some; areuof (other cross-sectional shapes-ridependingon the choice of the manufacturer. of.- the lamp. h

Considering the. amount of each electrode whic'h..is. necessarily held in=v itsi'clamp; .the amount of each electrode which lies in its guide, and therequired spacingof the arc'tromaeacli guide, no electrode can-be: burned-shorter than about 2% ,incheswithiarc lamps presently available. With a negative electrode having an original lengthof -9 inches thisLmeans that only apeproximately 72% of it is usable -inthe.:lamp.

When such are lamps are used'incommercial motion picture projecting machines; the.:e1ectrode' burning .rateiand the time required to project atleastone double reel. of. film .are two .addi tionalfactors .whichk. enter. intotheeprob'lem. Since a. standard negative .electrode burns at the rate of about 2 inches inidminutes, .and since the operator .must rhavea continuous-rzarc for abdut minutes torunone reel-of filmit is evident that the operator vmust ha-veanegative electrode in his lamp at least 4 /2" long when. he starts projecting ashort feature or newsreel or he will be unable .to run the rollof film continuously. Negative electrodes-Jess than 4% inches long are therefore discarded by projector operators. Disposing of a. 4 inch usedelectrode whichwasonly. 9 incheslong when new" means a ldssof approximately. 45%, and .a-iconsequent increased cost fornegative electrodes c-periyear A similar condition exists. with relationto the slower burningpositive electrodes;

fec-ting a-very material reductionz'in: the "total cost of electrodes.-

It is an additional important --ob ect of the invention to provide an auxiliary electrode holder which will not cause mis al-ignment of either ,ele'ctrode' as the holder passes into 'andacross the electrodegui'depand which willfreely pass through most; if not all, present electrode guides without changing the vertical or horizontal position. of theelectrode which it carries, vand without the necessity of modifying thecross sectional shape of the guide:

The invention,- together with other objects attending its production, will be more clearly understoodwhen thefollowingdescription is read inwconnection with the accompanying drawings, in which Fig-1 is a side schematic viewof the working parts of a standard are projection lamp with the carbon electrodes shown in broken'lines;

Fig. 2 is aninverted perspective view 'of apreferredform of electrode holder. embodying this invention;

Figs.-3 and 4 are top andbottom views respectively :of the holder;

- Fig. 5 is a right side view-ofthe holder mounted in a conventionalclamp'of an arc lamp assembly, theclamp being shown. fragmentarily;

Fig. dais a left side view of .the holder, th broken-lines indicating the relative position oc-'- 'cupied-by ana electrode when clamped in the holder; 7

Fig. 7 is anend viewof the holder taken looking directly into the electrode clamping end;

Fig; 8 is a lateral section takenvalong the line -88 of 5;

Fig. 9 is -a='sectional viewtaken along the line 9-4! of Fig.- 3,'andillustrates thecomplemental shape of the buttend of a conventional electrode and-theele'ctrode holdingsocket in th'eholder;

and,

Figs. 10, 11, and 12 iare end views of the holder operatively associated with three types of standard or conventional electrode guides; and

Fig; l3'is :anend view of a difierent type of holder embodying the "invention, operatively associated with a standard guide.

The standard lamp assemblyshown in Fig. 1 includes an independentlysupported Itrack I5,'a traveling/negative electrode carriage l 6 anegative electrode clamp I! which is a part of and travels with the carriage l6, and a stationary negative electrode guide l8 which serves to support and position the burning end of the electrode during lamp operation. The assembly also includes a traveling positive electrode carriage IS, a positive electrode clamp 20 which is a part of and travels with the carriage l9, and a stationary but adjustable positive electrode guide 2| mounted on a-supporting standard 22.

The two carriages l6 and l 9 are suitably power driven, and are automatically moved slowly toward each other during operation of the lamp to compensate for the slow disintegration of the two electrodes at the arcing point. The electrodes 23 and 24 slide through the guides l8 and 2| respectively, as the carriages move toward each other. The speed of movement of the carriages is coordinated, each moving at a rate equivalent to the burning rate of its respective electrode. The guides l8 and 2| are ordinarily set from 2 /2 to 3 inches apart, and the arcing takes place approximately midway between them during operation of the lamp. This spacing prevents are heat from melting or otherwise damaging the guides, and necessitating their replacement. When either of the electrode clamps I! or approaches its respective electrode guide l8 or 2|, the operator replaces the electrode at the first opportunity, to prevent interruption of his projection of a subsequent roll of film. The, partially burned electrode is discarded.

After an electrode has been partially burned and replaced, the discarded portion may be placed in the holder of this invention and burned.

The embodiment of the invention illustrated in the drawing includes an elongated shank 25, which is preferably the same cross sectional size and shape as the electrode, and can thus be easily received and secured in the clamps l! or 20. It also includes an integral electrode clamping head, designated as a whole by the numeral 26.

The head 26 is divided longitudinally by a saw cut into two cooperating electrode clamping jaws 21 and 28, both of which are integral with the shank 25, but are movable slightly toward each other due to the inherent resilience of the steel of which the holder is made. An elongated socket 29, of substantially the same cross sectional size and shape as the electrode to be held, is cut longitudinally into the free end of the head 26, part of the socket being formed in each of the jaws 21 and 28. The axis of the socket should coincide with the longitudinal axis of the shank 25. As shown in Fig. 9 the inner or blind end of the socket is shaped to receive the butt end of the electrode so that the corresponding surfaces of both the electrode and holder are substantially continuous.

The outer side surface of the jaw 2'! lies in a plane which is tangent to the cylindrical surface of the shank 25. The surface 3| of the jaw 28 also lies in a plane which is tangent to the surface of the shank 25, and the two surfaces 30 and 3| lie in planes which preferably intersect each other at an inclined angle of 60, the reason for which will be herein explained.

The two jaws 21 and 28 are provided with aligned transverse holes to receive a clamping screw 32, as clearly shown in Fig. 8. The bored hole in the jaw 28 is slightly larger in diameter than the screw 32 and is smooth walled to permit the screw to turn freely therein. The hole in jaw 21 is threaded. Thus, when the screw is tightened, the two jaws 21 and 28 are drawn toward each other, and exert a clamping force on that end of the electrode which is seated in the socket 29.

Figs. 10 to 12 inclusive illustrate the reason for forming the holder head 26 in the cross sectional shape described, with particular reference to the angle between the surfaces or faces 30 and 3!. The purpose is to permit the holder to pass through electrode guides of varying cross sectional shapes without causing the electrode to mis-align either laterally or vertically with respect to the other electrode.

Fig. 10 shows the described holder passing through a guide 33 whose inside or electrode contacting surfaces diverge at an angle of 60. It will be seen that if the shank 25 of this holder is properly oriented at the time it is inserted in either of the clamps I! or 20, the surfaces 30 and 3| will contact and slide along the diverging inside surfaces of the guide 33 as the holder and its partially burned electrode are moved longitudinally by'the carriage, and that the contact of the holder surfaces with the guide surfaces will not in any way affect the straight line travel of the electrode 23 clamped in the holder. This is true because the surfaces 30 and 3| of the holder are tangent to the surface of the electrode 23 as well as to the shank 25, and diverge at the same angle as the inside surfaces of this particular guide.

Fig. 11 illustrates the holder and its electrode 23 passing through what is commonly known as a type guide 34. With this type guide the holder shank is oriented in the clamp I! so that the surface 30 aligns with one inside surface of the guide. The partially burned electrode, the holder head 26, and the shank 25 may then pass through the guide without altering the straight line travel of the electrode,.and without disturbing its alignment with its cooperating electrode.

Fig. 12 shows a guide 35 having a still difierent cross sectional configuration. When the holder is used with this type of guide, the holder shank 25 is oriented in the electrode clamp 2!; to position the surface 30 in the same plane as the horizontal surface 36 of the guide. Thus as the lamp carriage moves the holder and its electrode 24 slowly toward the arcing point, the head 25 of the holder glides smoothly over the supporting surface of the guide without in any way disturbing the alignment of the burning electrodes.

Fig. 13 illustrates a slightly different embodiment of the invention associated with a 90 guide. It is identical in construction to the holder described, except for the cross sectional shape of the jaws 38 and 31, and the relative location of the electrode clamping socket in the head, both difierences being clearly shown in this drawing figure. This type of holder works well in any 90 guide, but will not work in a 60 guide 33, or

in a horizontal guide 35.

Having described the invention with sufficient clarity to enable those familiar with this art to construct and use it, I claim:

A holder for a conventional cylindrical electrode of an arc lamp comprising: a cylindrical shank of the same diameter as the electrode to be held; an enlarged integral head projecting longitudinally from one end of the shank and laterally to one side thereof only, the opposite side surfaces of the head adjacent the shank lying in intersecting planes tangent to the surface of the shank, the included angle of intersection of the two planes being between 28 and 139; a cylindrical electrode receiving socket in said head 5 of the same-diameter as said shank and extending to the end of the shank, the socket axis being aligned with the shank axis, and a portion of the socket between the lines of tangency of the opposite side surfaces of the head being open throughout the length of the socket; an axial slot in the head dividing it into two electrode clamping jaws; and means for forcibly moving said jaws toward each other to clamp an electrode in said socket, whereby an electrode seated in said socket abutting the adjacent end of the shank has a socket exposed side surface forming a substantial continuation of the adjacent shank surface.

EUGENE R. SUTTLE.

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

UNITED STATES PATENTS Number Name, Date 2,133,407 Stone Oct. 18, 1938 2,183,846 Robb Dec. 19, 1939 2,207,664 Granville, Sr July 9, 1940 10 2,215,401 McCroskey Sept. 17, 1940

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