US2559547A - Machine for making an electrode assembly - Google Patents

Description

July 3, 1951 P. REED MACHINE FOR MAKING AN ELECTRODE ASSEMBLY 6 Sheets-Sheet 1 Filed Oct. 12, 1949 KOFOZ on NA...

mm wv mm R. w S. on o: 8. m E E n on M R M f Ow G 09 O V O B. N T I|| I- i I L Y m E F u u mm u. m2 G m2 6 a E 8 f 8 N C M 5 o: S R No P v. w B 3 5 8 N 6 k 2 o! aw 5:; V 52; fl EH23 565:6 195 8 L l 33 52% m. 3 31 n 6 Sheets-Sheet 2 INV EN TOR.

llvll PRICE LREED P. L. REED Ii 010? b0 0 MACHINE FOR MAKING AN ELECTRODE ASSEMBLY July 3, 1951 Filed Oct. 12, 1949 ATTORNEYS.

y 1951 P. L. REED MACHINE FOR MAKING AN ELECTRODE ASSEMBLY 6 Sheets-Sheet 3 Filed Oct. 12, 1949 INVENTOR. PRICE L. REED BY AT TORNE S.

July 3, 195] P. I.. REED 2,559,547

MACHINE FOR MAKING AN ELECTRODE ASSEMBLY Filed Oct. 12, 1949 s Sheets-Sheet 4 I uz INVENTOR. PRICE L'. REED ATTORNE S.

y 1951 P. L. REED 2,559,547

MACHINE FOR MAKING AN ELECTRODE ASSEMBLY QA-Jwr AT T0 RN YS.

6 Sheets-Sheet 6 IN V EN TOR.

P. L. REED MACHINE FOR MAKING AN ELECTRODE ASSEMBLY July 3, 1951 Filed Oct. 12, 1949 n m "m "u we a an n u v um I 8 l4 Ne 81 mm 3. 3 No 8. t 8 3 3 3 n "u -v PRICE L. REED BY ATTORNEY Patented July 3, 1951 MACHINE FOR MAKING AN ELECTRODE ASSEMBLY Price L. Reed, Royersford, Pa., assignor to Superior Tube Company, Philadelphia, Pa., a corporation of Pennsylvania Application October 12, 1949, Serial No. 120,911

9 Claims.

This invention relates to the manufacture of cathodes for thermionic tubes and has particular reference to the disc-type of cathode which is used in various cathode ray tubes, television pickup tubes and tubes of the so-called lighthouse construction.

In tubes of the type just mentioned the thermionic emission is obtained from a relatively small, cup-shaped disc coated with alkaline earth oxides. The disc must be rigidly mounted within the tube a few thousandths of an inch from a grid member and in accurate parallel alignment therewith. The disc is supported by a metal tubular member which may be of any conventional form, i. e., seamless or of lock seam, welded, welded and drawn, boxed, orwrap-around ribbon type, and also serves as a means of conducting heat to the 'disc or cup carrying the oxides to heat it to electron-emitting temperature. An insulated tungsten, molybdenum or similar wire is usually placed within the tube to provide sufilcient heat by electrical resistance to make possible attainment of the proper temperature.

In order to support the cathode assembly, ceramic or similar heat-resistant insulators are employed. These insulators, generally in the form of a flat disc, are mounted on the tubular member prior to the attachment of the cup to the tubular member. The attachment of the cup to the tubular member is generally accomplished by inserting the tubular member into the cup which fits as a snug cap over the end of the tube and then welding the cup to the tube.

It is an object of this invention to maintain an accurate dimension longitudinally between the face of the disc and the face of the cup while welding the cup to the tube supporting the disc.

Another object of this invention is to maintain accurate parallel plane alignment between the face of the disc and the end face of the cup while welding the cup to the tube supporting the disc.

In my Patent N 0. 2,476,454, issued July 19, 1949, there is disclosed a machine for making the cathode assembly which welds the cap to the tube one weld at a time and rotates the assembly to successive welding positions under a single welding electrode.

It is a further object of this invention to provide means for automatically making a plurality of welds evenly spaced around the periphery of the cap without moving the assembly until the welding is completed.

These and other objects of the invention will become apparent from the following description, read in conjunction with the accompanying drawings, in which:

2 Figure 1 is a plan view of the apparatus involved;

Figure 2 is an axial section of the welding and gauging means taken on the plane indicated by 22 in Figure 1 above the mounting plate, and an elevation of the apparatus below the mounting plate;

Figure 3 is a side elevation of the apparatus showing the control mechanism lying below the mounting plate;

Figure 4 is a front elevation of the gauging and welding means and the mechanism lying below the mounting plate;

Figure 5 is a front elevation of the welding means, as viewed from between the gauging means and the welding means;

Figure 6 is an enlarged fragmentary side elevation, entirely in section, showing the cathode assembly held by the gauging means in position to be welded with two of the welding electrodes in position for welding;

Figure '7 is a diagram of the electrical circuit involved; and

Figure 8 is a side elevation of the welding and gauging means shown in the lower portion of Figure 1.

Referring to the figures there is shown a driving motor 2 coupled through the shaft 3 to a speed reducer 4 which, in turn, drives the shaft 5 and the one-revolution clutch 6. The one-revolution clutch 6 may be of any conventional type employing a solenoid controlled release electrically energized through the lead wires 8 and I0. When the one-revolution clutch is energized, sprocket wheel l2 which is afiixed to the shaft ll driven by the clutch 6 will rotate for one revolution driving the chain 14. The chain l4 drives the sprocket wheel [6. The sprocket wheel l6, having twice the number of teeth of the sprocket wheel l2, will be .driven one-half a revolution with each revolution of the sprocket wheel l2 or with each operation of the one-revolution clutch 6. Inasmuch as the motor 2, the speed reducer 4 and the one-revolution clutch 6 may take the form of any conventional apparatus of this type, and are not essential parts of the present invention, they will not be described in detail.

The welding apparatus shown generally at I in Figure 2 is supported by the supporting member l8 which is mounted on the mounting plate 20. Passing through a bore in the supporting member 18 is the insulating sleeve 22 which is held in position within the member l8 by the set screws 24.

Mounted on the portion of the insulating sleeve 22 extending outwardly from the left side of supporting member [8, as viewed in Figure 2, is the member 2G which is held in position on the insulating sleeve by means of set screws 28. Rotatably mounted on the member 26 is the member 39 which is retained in proper position by virtue of its bearing on the face 32 of the member 26 and its bearing on the insulating collar 34 which is located between the extended flange portion 36 of the member 3i! and the support I8. Rigidly mounted to the extended flange portion -35 of the member 33 is the sprocket wheel H5 which is driven as the result of operation of the onerevolution clutch t, and causes the member to rotate for one-half a revolution about the stationary member 26 with each operation of the one-revolution clutch.

Mounted within the extended rim portion SI of the rotatable member 30 are a pair of cam members 33 which are adapted to rotate with the member 3!! and depress the electrode mounting assemblies as will be hereinafter described. Mounted on the external surface of the rotatable rim iii are four buttons or projections 35.

Slidably mounted within the radially disposed slots 23?, within the stationary member 26, are the electrode mounting blocks 38. Each of the blocks 33 is slidably retained within the slots 3'! by the two retaining plates 39 which are afiixed to the stationary member 26 by screws 4|. The electrode mounting blocks are urged in radially outward positions by the spring 23 acting between the extended portion 25 of the block 38 and the inner end of the radially extending slots 2| in the stationary member 25.

The machine, as described herein, contains four electrodes and four electrode mounting assemblies. It will be obvious, however, that any number of pairs of electrodes and electrode mounting assemblies may be used within the limitations imposed by the space limitations and the pro portionate sizes of the parts involved. The following description of the electrode, and electrode mounting assemblies, is directed to one assembly only, it being understood that all of the assemblies are alike.

Mounted on the electrode supporting block 38 by means of the screws 49 is the electrode mounting yoke 42. The mounting yoke 42 is insulated from the support block 33 by means of a sheet of insulating material 44 lying between the yoke 42 and the block 313 and the insulating sleeves 46 surrounding each of the mounting screws M Contained within bores passing through the extended ends of the mounting yoke 42 is the electrode sleeve 43 to which is affixed a collar 50. Mounted over the electrode sleeve 43 is a spring 52. The inner end of the spring bears against a collar 59 and the outer end bears against the inside of the outer extended portion of the yoke 42. Mounted within the electrode sleeve 48 is the electrode holder 54, in the inner end of which is inserted the electrode tip 56.

Clamped to the inner ends of the electrode holders are the conductor lead mounting blocks 59, Connected to the blocks 5% and [ii are the flexible lead wires 64 and 65, joining the blocks as and El to the welding cable 66, and connected to the blocks 62 and 63 are the flexible lead wires 6i and 68 joining the blocks 62 and B3 to the welding cable 69. The welding cables 66 and 69 are connected to a conventional type welding current timer H! which receives power from power lines I53 and I55.

Each of the conductor lead mounting blocks 69, 6!, 62 and 63 serves the additional purpose, when clamped against its associated electrode sleeve by the action of its associated clamping as viewed in Figure 2.

screw 59, of compressing the sleeve against its associated electrode holder 54, thus firmly retaining the electrode holder 54 in its preestablished position within the sleeve 48. The outer end of the electrode holder is threaded and a nut 58 is provided to facilitate the setting of the position of the electrode holder within the electrode sleeve. For example, the electrode holder 54 is placed within the electrode sleeve 48 in a posttion inwardly further than will be required. Then the clamping screw 59 is partially tightened and the mounting block will hold the electrode holder in position within the sleeve, and then, by tightening the nut 58, the electrode holder may be drawn outwardly through the sleeve to exactly the desired position, after which the clamping screw 59 is tightened completely.

Mounted within the insulating sleeve 22 in the support member I8 is the sleeve member H which is held in position in the sleeve 22 by set screws '52. The member ll contains a central bore 13 which is threaded at its right hand end The partially threaded sleeve member 14 is inserted into the bore '13 and may be adjustably positioned within the member H by means of the screw threads and locked into position by the lock nut '75. ber 14 contains a partially threaded central bore within which is mounted the partially threaded rod 16 which may be adjustably positioned by means of the screw threads and locked in that position within the member '14 by the lock nut '13. The rod 16 has a portion of reduced diameter 19 extending for approximately half its length from the left hand end, as viewed in Figure 2.

Mounted within the enlarged central bore 11 at the left hand of the sleeve member H, as viewed in Figure 6, is the solid cylindrical member 80. The member is held in position on rod 16 by means of the set screw 82. The member 80 is positioned to bear against the spacer member 84 which, in turn, bears against the end of the sleeve member 14. Mounted in each of three bores 36 uniformly spaced within the member 80 is a plunger member 88 which is urged outwardly by the spring member 96 acting between the plunger rod collar 92 and the plug member 94 in the member 80.

It will be observed that the position of the member 80 may be longitudinally adjusted by turning the sleeve member 14 within the member H, and that the relation between the left hand end of the rod member 16 and the left hand end of the member 80 may also be adjusted by positioning the rod member 16 within the sleeve member 14.

Also mounted on the base plate 20 is the member 96, containing the gib slot 97, within which is slidably mounted the gib member 98, supporting the member 99 on which is mounted the gauge plate I00 and the micrometer assembly, generally indicated at IUI.

The gauge plate IUD, which is fixedly mounted to the member 99, has on its upper portion four projections I02 separated by the central bore I03. The end faces I94 of these projections are accurately machined faces lying on a common plane perpendicular to the surface of the bed plate 20 and normal to the longitudinal axes of the rod 16. The micrometer assembly includes the fixed member I 05, mounted on the member 99, and containing the threaded central bore I06 within which is mounted the adjustable micrometer stem [01. Attached to the micrometer stem i0! is the conventional micrometer rotatable outer member I08 carrying the usual micrometer scale The sleeve mem' markings. Thus, by adjusting the micrometer, the longitudinal distance between the end III of the micrometer shaft and the end faces I04 of the gauge plate extension can be accurately adjusted.

Also attached to the base plate 20 is the bracket I42, mounting the limit switch I44 and the limit switch actuating lever I46. Mounted on the lever I46 is the projection I48 which is positioned so as to be depressed by the projections 35 on the rotatable member 30 when the member 30 is rotated. Upon depression, the lever I46 actuates the limit switch I44 closing the circuit therethrough and initiating the operation of the welding timer I and causing welding current to flow, as will be hereinafter described.

Mounted below the base plate 20 is the mechanism for actuating the micrometer and the gauge plate mounting gib 98. This mechanism includes the member II2 which is adapted to be extended downwardly and provided with a foot pedal, or other suitable means not shown, which may be actuated by an operator. The member II 2 has the flattened upper end portion II3 which is pivotally mounted by means of the pin II4 to a supporting bracket H5. The supporting bracket II 5 is attached to the underside of the base plate 20. Aifixed to the flattened portion II3 of the member H2 is the pin II 6 which is engaged by the slot H7 in one end of the lever member H8. The lever member H8 is pivotally mounted on the mounting bracket I I 5 by means of pin I I9.

The other end of the lever member IIB has an extended portion I which contains the bore I2I through which is passed rod member I22. The rod member I22 is held in engagement with the lever member extension I20 by means of the rod collar I23 and the spring I24. The tension of the spring I24 may be adjusted by setting the locking pair of lock nuts I26 in any desired position on the threaded end of the rod I22.

Mounted on the other end of the rod I22 is the tongue I28. The tongue I28 is coupled to the clevis I30 by a pin I32. The clevis I30 is mounted on the rod member I34 which is rigidly afllxed to the sliding gib 98.

Also mounted on the underside of the mounting plate 20 is the bracket member I36. Aflixed to the bracket member I36 is the block I37. The stop screw I38 passes through a threaded bore in the block I31 and is locked in position by the lock nut I39. Also mounted on the bracket I 36 is the limit switch I40. Both the stop screw I38 and the limit switch I 40 are adapted to be engaged by the lever member I I8 upon operation of the mechanism, as will be hereinafter described.

When it is desired to assemble a cathode assembly by welding a cap to a tube and disc assembly, the operator will place a cathode cap I50 over the proper end of a tube I52 of a cathode tube and disc assembly and place this assembly over the end of the rod member I6, as shown in Figure 2. The tube and disc and cap assembly are more clearly shown in Figure 6 which is drawn to show the relative positions of the various parts involved in gauging and welding the cap to the tube at the time the welds are made.

After having placed the unwelded electrode assembly into position over the end of the rod member I6, the operator will actuate the member H2, extending below the base plate 20, moving it to the position 2', as shown in construction lines in Figure 3. This motion of the member II2 results in moving lever member I I8 into the position also shown in construction lines and numbered H8 whereat motion is arrested by the stop screw I38 and its end portion I20 actuates the limit switch I 40. When the lever member II 8' is in this depressed position, the lever end portion I20 will bear against the spring I24 which in turn bears against the lock nuts I26 drawing the rod I 22 to the right, as viewed in Figure 3, to the position I22 causing the rod member I34 to assume the position I34 and causing the end I I I of the micrometer stem and gauge faces I04 to move to the right and engage the tube disc and cap assembly, as shown in Figure 6, with a force as determined by the degree of compression of spring I24.

With the parts in this position, the end III of the micrometer shaft will bear against the oathode assembly cap I50, holding it firmly against the end face of the rod I6. The nd faces I04 of the gauge plate extensions bear against the face of the disc I54 causing it to depress the spring loaded members 88 back into the plug 80, with the result that the action of the springs 00 holds the disc I54 firmly against the gauge plate faces I04. Thus the relation between the left hand face of the disc I54, as viewed in Figure 6, and the left hand or outer surface of the cap I50 is firmly established by the gauging means as to both parallel plane alignment and longitudinal dimensional relation.

There is provided a suitable electric current timing means I5I which may be any one of a number of conventional timers and which receives power from the power lines I 53 and I 55 and is initiated by the closure of microswitch I40 to pass current through leads 8 and I0 to the solenoid control coil 9 of the one-revolution clutch 6. The timer I5I is adjusted to energize the coil 9 for a sufiicient period to permit the one-revolution clutch to commence its operation and to deenergize the coil for a sufficient time before the completion of one revolution of the clutch in order to prevent a second operation of the clutch from occurring.

When the operator has actuated the member II 2 and the lever II 8 to engage the cathode assembly parts within the welding and gauging means, as hereinbefore described and as shown in Figure 6, further motion of the members H2 and H8 will not move the gauge and micrometer assembly but will merely compress the spring I24 as shown at I24 as the lever II8 moves to its extrem position where it actuates the limit switch I40 and its motion is arrested by the end of the stop screw I38.

Closing the contact of the limit switch I40 initiates the timing means I5I actuating the onerevolution clutch. Upon operation of the onerevolution clutch, the member 30 carrying the cam members 33 will be rotated for half a revolution, as previously described. As the rotating cam members 33 engage the outer ends of an oppositely disposed pair of welding electrode mounting blocks 38 the mounting blocks are cammed inwardly b the bevelled portion I60 of the leading edges of the cams 33 as the cams rotate in a clockwise direction, as viewed in Figure 5. The continued rotation of the member 30 and the cams 33 will cause the inner cam faces I62 to pass over the ends of the electrode mounting block 38 holding the electrode mounting block in radially inward position during the period of dwell of the cam faces I 62; and further rotation will allow the mounting block 38 to move outwardly over the bevelled trailing edges IBI of the cam in response to the urging by the spring member 23.

When a cam moves a mounting. block inwardly the yoke member 42 which is carried by the mounting block will bear against the upper portion of the spring 52'. The other end of the spring, bearing against the member 58, will carry the electrode sleeve and the electrode holder in wardly into contact with. the cathode cap, as shown in Figure 6. After travel of the electrode and electrode sleeve has been arrested: by contact of the electrode tip with the cathode cap, further motion of the block 38 and the yoke member 42' will serve only to compres the spring 52. This spring compression provides an electrode tip force and an electrode having yieldable contact with the cathode cap;

Referring to Figure 5, when the rotatable member 3I' is rotated clockwise to a position where the cam members 33 have depressed the vertically lying electrode mounting blocks 38, the button 35, shown at the bottom of the member 3I in Figure 5, will have rotated to a position where it will actuate the microswitch Me. Upon actuating limit switch M4, welding timer l9 will be operated and welding current passed through welding cable 66, jumper lead 64 to the block 60 and thence through the electrode sleeve 48, electrode holder 54 and electrode tip 55 through the oathode cap I50, the cathode tube I52, the rod IE, which is made of a conductive material such as brass, through the opposite side of the cathode sleeve I52 and the opposite side of the cathode cap I50 into the electrode tip 56, electrode holder 54, sleeve A8, block 62, jumper E8 and the welding cable 69 back to the welding timer. At the points of contact of the two electrodes 56 to the cathode cap I50, resistance welds will be form-ed between the cap I50 and the tube I52 in. a conventional manner. The period of dwell or the length of the inner face I52 of the cam 33 may be selected to provide a sufficiently long time duration of contact for the electrodes upon the oathode cap to provide a suitable welding condition. With the apparatus as described and the member 30 making a half a revolution with each operation, it will be obvious that the two pairs of welding electrodes are each depressed once with each operation of the one-revolution clutch. Thus, two pairs, or a total of four welds, will be made on the cathode assembly with each operation of the welding apparatus.

After the one-revolution clutch has completed its cycle and the welding timer has interrupted the flow of welding current, the operator may return the member II2 to its normal position whereupon, by the action of rod I22, the gib 98 carries the micrometer and gauge assembly back away from the cathode assembly to a position as shown in Figure 2. The operator may then remove the welded assembly from the machine and place into the machine a new assembly for weldmg.

In my copending application, Serial No. 75,577, filed February 10, 1949, there is disclosed a method and apparatus for mounting the disc I54 on the tube I52 by forming beads in the tube on each side of the disc.

In the copending application of Thomas H. Briggs, Jr., Serial No. 75,845, filed February 11, 1949, now U. S. Patent 2,551,871, granted May 8, 1951, there is disclosed a method and apparatus for striking the beads, closing the beads and causing them to bear flatly against the disc, as shown in the present application.

It is extremely difiicult to maintain the extreme degree of accuracy of dimension required between the face of: the cap member I50 andthe face of the disc I 54 by relying on. providing the proper length of tubing I52 extending beyond the face of the disc. This problem is further complicated by the inconsistencies occurring in the bend radius attained in the manufacture of adrawn cap such as member I55. The present invention provides a means fOr assembling the cap to the tube with the high degree of accuracy required since neither the length of the tube nor the dimensions of the cap determine the final central spacing of the face of the insulating disc from the face of the cap.

A particularly desirable feature of the present invention is that, when the cap and tube and disc assembly have been positioned in the gauging means and are accurately held in proper alignment, the welding operation is completed before the cap and tube and disc assembly are released by the gauging means. Thus, once the parts have been properly positioned, all of the welding is completed before the parts are released. Thus, there is assured accurate alignment between the parts.

What is claimed is:

1. A welding apparatus adapted to be associated with a welding current timer and comprising at least one pair of radially disposed 0pposed welding electrodes, individual means re"- taining each of said electrodes, means radially slidably mounting each of said electrode retainin means, means rotatable about the circumference of said mounting means for intermittently depressing said retaining means inwardly within said mounting means, said electrodes moving inwardly in response to the action of said depressing means on said retaining means and engaging opposite sides of parts to be Welded together, and means for initiating 'a welding current timer to pass welding current through said electrodes and the parts when said electrodes are in engagement therewith.

2. A weldin apparatus adapted to be associated with a welding current timer and comprising at least one pair of radially disposed opposed welding electrodes, individual means yieldably retaining each of said electrodes, means radially slidably mounting each of said electrode retaining means, means rotatable about the circumference of said mounting means for intermittently depressing said retaining means inwardly within said mounting means, intermittently rotating means actuating said rotatable depressing means, said electrodes moving inwardly in response to the action of said depressing meanson said retaining means and yieldably engaging opposite sides of parts to be welded together, and

means for initiating a welding current timer to pass welding current through said electrodes and the parts when said electrodes are in engagement therewith.

3. A welding apparatus adapted to be associated with a welding current timer and comprising at least one pair of radially disposed opposed welding electrodes, individual means yieldably retaining each of said electrodes, means radially slidably mounting each of said electrode retaining means, means rotatable about the circumference of said mounting means for intermittently depressing said retaining means inwardly within said mounting means, intermittently rotating means actuating said rotatable depressing means. said electrodes moving inwardly in response to the action of said depressing means on said retaining means and yieldably engaging opposite sides of parts to be welded together, and means responsive to the position of said intermittently rotating means for initiating a welding current timer to pass welding current through said electrodes and the parts when said electrodes are in engagement therewith.

4. A welding apparatus adapted to be associated with a welding current timer and comprising a plurality of pairs of radially disposed pposed welding electrodes, individual means retaining each of said electrodes, means radially slidably mounting each of said electrode mounting means, means rotatable about the circumference of said mounting means for intermittently depressing successive opposed pairs of said retaining means inwardly within said mounting means, successive pairs of said electrodes moving inwardly in response to the action of said depressing means on said retaining means and engaging opposite sides of parts to be welded together, and means for successively initiating a welding current timer to pass welding current through each pair of electrodes and the parts to be Welded when said electrodes are in engagement therewith.

5. A welding apparatus adapted to be associated with a welding current timer and comprising a plurality of pairs of radially disposed opposed welding electrodes, individual means retaining each of said electrodes, means radially slidably mounting each of said electrode mounting means, means rotatable about the circumference of said mounting means for intermittently depressing successive opposed pairs of said retaining means inwardly within said mounting means, intermittently rotating means actuating said rotatable depressing means, successive pairs of said electrodes moving inwardly in response to the action of said depressing means on said retaining means and engaging opposite sides of parts to be welded together, and means for successively initiating a welding current timer to pass welding current through each pair of electrodes and the parts to be welded when said electrodes are in engagement therewith.

6. A welding apparatus adapted to be associated with a welding current timer and comprising a plurality of pairs of radially disposed opposed welding electrodes, individual means retaining each of said electrodes, means radially slidably mounting each of said electrode mounting means, means rotatable about the circumference of said mounting means for intermittently depressing successive opposed pairs of said retaining means inwardly within said mounting means, intermittently rotating'means actuating said rotatable depressing means, successive pairs of said electrodes moving inwardly in response to the action of said depressing means on said retaining means and engaging opposite sides of parts to be welded together, and means responsive to the position of said intermittently rotating means for successively initiating a welding current timer to pass weldin current through each pair of electrodes and the parts to be welded when said electrodes are in engagement therewith.

'7. A welding apparatus adapted to be associated with a welding current timer and comprising at least one pair of radially disposed opposed welding electrodes, individual means yieldably retaining each of said electrodes, means radially slidably mounting each of said electrode retaining means, means rotatable about the circumference of said mounting means including cams for intermittently depressing said retaining means inwardly within said mounting means, intermittently rotating means actuating said rotatable depressing means, said electrodes moving inwardly in response to the action of said depressing means on said retaining means and yieldably engaging opposite sides of parts to be welded together, and means for initiating a welding current timer to pass welding current through said electrodes and the parts when said electrodes are in engagement therewith.

8. A welding apparatus adapted to be associated with a welding current timer and comprising at least one pair of radially disposed opposed welding electrodes, individual means yieldably retainin each of said electrodes, fixed means radially slidabl mounting each of said electrode retaining means, means slidably mounting each of said electrode retaining means, means rotatable about the circumference of said mounting means for intermittently depressing said retaining means inwardly within said mounting means, intermittently rotating means including a one-revolution clutch actuating said depressing means, means controllable by an operator to initiate the operation of the onerevolution clutch, said electrodes moving inwardly in response to the action of said depressing means on said retaining means and yieldably engagin opposite sides of parts to be welded together, and means responsive to the position of said depressing means for initiating a welding current timer to pass welding current through said electrodes and the parts when said electrodes are in engagement therewith.

9. A welding apparatus adapted to be associated with a welding current timer and comprising a plurality of pairs of radially disposed opposed welding electrodes, individual means retaining each of said electrodes, means radially slidably mounting each of said electrode mounting means, means rotatable about the circumference of said mounting means including cams retaining means inwardly within said mounting means, intermittently rotatin means actuating said rotatable depressing means, successive pairs of said electrodes moving inwardly in response to the action of said depressing means on said retaining means and engaging opposite sides of parts to be welded together, and means for successively initiating a. welding current timer to pass welding current through each pair of electrodes and the parts to be welded when said electrodes are in engagement therewith.

PRICE L. REED.

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

UNITED STATES PATENTS Number Name Date 1,061,378 Heany May 13, 1913 1,122,665 Thomson Dec. 29, 1914 1,554,385 Still Sept. 22, 1925 2,079,042 Saives May 4, 1937 2,183,219 Hollesen Dec. 12, 1939 2,372,413 Weightman Mar. 27, 1945 2,476,454 Reed July 19, 1949

Images