US2476454A - Machine for making electrode assemblies - Google Patents

Description

July 19, 1949. p REED 2,476,454

MACHINE FOR MAKING ELECTRODE ASSEMBLIES Filed Feb. 10, 1949 2 Sheets-Sheet 1 INVENTOR. PRICE L REED July 19, 1949. P. L. REED 2,476,454

MACHINE FOR MAKING ELECTRODE ASSEMBLIES Filed Feb. 10, 1949 2 Sheets-Sheet 2 INVENTOR. PRICE L. REED ATTORNE S.

Patented July 19, 1949 MACHINE FOR MAKING ELECTRODE ASSEMBLIES Price L. Reed, Royersford, Pa, assignor to Superior Tube Company, Philadelphia, Pa., a corporation of Pennsylvania Application February 10, 1949, Serial No. 75,578

6 Giaims.

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 pick-up tubes, and tubes of 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 plane alignment therewith. The disc is supported by a metal tubular member which may be of any of the conventional forms, i. e., seamless or of lockseam, welded, welded and drawn, boxed, or wrap-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 inside the tube to provide sufficient 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 a 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 cap 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 cap while welding the cap to the tube supporting the disc.

It is a further object of this invention to maintain accurate parallel plane alignment between the face of the disc and the face of the cap while welding the cap to the tube supporting the disc.

Another object of the invention is to provide means for automatically rotating the disc, tube and cap assembly while making a plurality of successive welds evenly spaced around the periphery of the cap.

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

Figure lis a perspective elevation of the apparatus involved;

Figure 2 is a vertical section of a portion of the apparatus shown in Figure 1, the section being taken through the axis of the cathode assembly; and

Figure 3 is a vertical section taken on the plane indicated by the trace 3-3 in Figure 2.

In Figure 1 there is shown a conventional bench type spot welder comprising a support post IE3 which is mounted on a base plate I2. Moving within the support post is actuating rod 14 which extends downward through the base plate I2 and is coupled with a foot treadle (not shown) below the table on which the base plate rests. The upper end of the actuating rod [4 is pivotally connected to member 55, which is pivoted on pin iii. The other end of member [6 is forked and provided with inwardly directed pins engaging the slidable upper electrode assembly 20 within the slots 22.

When the foot treadle below the table is moved by the operator the actuating rod causes member it to rotate about pin [8 moving the upper electrode assembly 20 downward bringing the electrode 24 into contact with the work in a position hereinafter described in detail.

The upper electrode assembly 20 is a conventional assembly comprising a spring loading mechanism and welding current control timer initiating switch. These assemblies are well known to the art and need not be described here.

Also mounted on the support post I!) and insulated therefrom by insulating bushing 26 is the lower welding arm 30. Mounted in the lower arm 36, as shown in greater detail in Figure 2, is member 32 which is rotatably mounted within the bore 34 and held against axial movement by screws 36 and 33. Formed as part of the member 32 is a ratchet S0. Rotatably mounted on member 32 is the housing 42 to which is affixed operating arm M. Mounted on the face of housing 42 by screws E32 is cover plate 64. Connecting link 43 connects operating arm 44 with the lever 48 which is pivotally mounted on pin i3 and is actuated by ac tuating rod i4 through the pin 50.

Cdntained within operating arm M is pawl 5'2 which is urged inwardly by the action of spring 54 and engages the faces of the ratchet lobes 51, 58 and 59 as will be hereinafter described.

Mounted within the member 32 and equally spaced from each other are three pins such as are shown at 66. Each pin is backed by a spring similar to that shown at 68 and has at its outer end a portion 61 of reduced diameter which engages within one of three holes 69 provided therefor in the ceramic disc member 14. Centrally mounted within the member 32 is the conducting rod is over which is placed the tube member 12 supporting the disc member I4 and the cap member it, these members forming the cathode assembly.

Also mounted on the base plate I2 is member I S on which is slidably mounted member 80 mounting a face plate 82, micrometer support plate 8 5 and micrometer locking bracket 83 in which is threaded micrometer locking screw 85. Threaded into support plate 84 is the internal micrometer member 86 into which is threaded micrometer stem member 81 which mounts the external micrometer member 88.

The upper edge of the face plate 82 must rise sufiiciently high above the center of the disc Hi that for any position of member 32 at least two of the pins will bear on the disc below the upper edge of the plate to provide stability in order that the disc will be held in a fiat position against the plate 82 by the action of spring load pins 66. The plate is notched at BI to provide clearance for the tube 72 and the cap I6.

Also coupled with the operating foot treadle (not shown) below the table is a second actuating rod 98 which is connected to rod I02, through arm $32, shaft 94 and arm 98, which are pivotally supported by mounting bracket IIlEl. Pivcted on a fixed pin N34 is arm Hi6 which is yieldably engaged by rod I02 upon motion of the rod to the left through spring I08 and non-yieldably engaged by rod Hi2 upon motion of the rod to the right through stop I01. The pin I Ill mounted on arm I06 engages the wall II 2 of a bore within the member 89.

When the operating foot treadle is depressed the rod I4 actuates member I6, causin the welding electrode assembly 20 to move downward and the electrode comes into engagement with the cap member It as shown by 26'. Actuating rod it working through member 58 also actuates lever 48, connecting link 46 and actuating member M, moving member Ml in a downward direction. a In Figure 3 the pawl 52 is sliding over the outer face of a ratchet tooth while the actuating lever M and the housing 42 are rotating in a counterclockwise direction, the lowermost extent of travel of which will allow the pawl 52 to spring radially inward into. a position of engagement below the face 59 of a ratchet tooth.

Simultaneously with this action the actuating rod 90 acting on rod I02, member I96 and pin H0. moves the member 8.9, face plate 82, and the micrometer assembly 86-, 81 and 88 to the left as viewed in Figure 2, causing the end face I2 of the micrometer rod 81 to press the cap member IS, against the end face I23 of the member ID with a force, dependent upon the resistance to compression afforded by spring I68. The force with which the spring acts can be adjusted by adjusting the position of nut I89 on the threaded portion I03 of the rod I02. Thus, the plane of the face of the cap. member i5 is fixed by the plane of the end. face I24 of the rod 81.

With the apparatus in the position shown the shoulders of the pins 66 are urged against the disc I4 by the action of Springs 68 thereby holding the disc member I4 fiat against the face of plate 82. It will be apparent that, by turning the external micrometer member 88, the dimension between the end face I24 of rod 81 and face of the plate 82 may be adjusted to any desired value, thereby accurately establishing the dimension between the face of the; disc member i l and the face of the cap member I6. When the micrometer has been adjusted to the desired position locking screw 85 is tightened against the micrometer 4 member 88 preventing subsequent motion thereof.

When the electrode member is in its lowermost position 24 as shown in construction lines in Figure 2, the welding current which may be supplied by a conventional welding current timer (not shown), passes through lead wire II4 into conducting member H6 through flexible jumper H3, conducting member I20, electrode 24, cap I6. tubular member 12, rod Ill, member 34, lower arm 3% and returns to the welding current timer through conductor I22. This flow of current forms a weld between the tube member I2 and the cap member I6 in a manner well known in the spot welding art.

After the weld has been made the operator releases the foot treadle allowing actuating rod id to move downwardly thereby raising the electrode 24 and raising connecting link 46 and operating arm as, thus rotatin the ratchet 49 in a clockwise direction, as viewed in. Figure 3, and thereby rotating the member 34, the pins 56 and the tube, disc and cap assembly through 9l to a position preparatory to making the next weld. When actuating rod I moves downwardly actuating rod st also moves downwardly thereby moving the rod I92 to the right allowing spring I88 to expand partially relieving the pressure applied on the cap member I6 between end faces lie an :23 of the rods 81 while the tube, disc and cap assembly rotate as a result of the operation of the cam G6. I

When the foot treadle is depressed for the next welding operation and the ratchet pawl 52 slides over the next successive ratchet tooth the memher 32 is restrained from rotating by the fricticn resulting from the remaining contact pressure existing between the ends of rods 81 and it and between the disc 74 and theplate. 82.

In my copendin application, Serial No. 75,527, filed Feb. 10, 1949, there is disclosed a method and apparatus for mounting the disc 74" on the, tube l2 by forming beads in the tube, on each side. of the disc.

In the copending application of Thomas. H. Briggs, J12, Serial No. 75,845,, February ll, 1949, there is disclosed a-methodandapparatus for striking the beads, closing the beads. and1causing them to bear flatly against the disc as'shown in the present application.

It is diificult to maintain the extreme, degree of accuracy of dimension required between the face of the cap member leand; the face of the disc member It by relying on providing the proper length of tubing 12 extending. beyond the face of the disc. This problem is further com? plicated by the inconsistencies occurring in the bend radius obtained in the manufacture or a drawn cap such as member It. The present invention provides means for assembling the cap to the tube with the high degr e f accuracy required since neither the length of the tube nor the dimensions of the cap determine-the final central spacing of the face i the insulating disc from the face of the cap.

When the foot treadle is released to an. extreme forward position the actuating rod 90, operating through arm as, shaft 94, arm 98, rod Hi2, stop 5537, member its. and pin HG, causes the member 88 to move to the right to av position entirely clear or the rod it and the electrode 24, thereby providing the necessary clearance required by the operator to insert the assembly for welding The operator having manually pressed cap it over the end of the, tube of a'tube and disc assembly slides the tube over-the rod III and rotates the tube and disc assembly to a position where the ends of the pins 66 drop into the holes 69 in the disc.

As the operator then depresses the foot treadle the member 80 moves to the left carrying with it the face plate 82 and micrometer member 81. When the face plate 82 engages the ceramic disc the disc and tube assembly are carried to the left forcing the pins 55 into member 32 compressing the springs 68. The spring loaded pins 66 hold the disc (in a fiat position) against the plate 82. The disc and tube will be moved to the left over member 10 until the cap 18 is firmly engaged between the ends of member 10 and member 81. When this position has been attained the tube 12 will generally have been withdrawn slightly from the original extreme position, in which it was assembled by the operator, within cap 16 before motion of the plate 82 is arrested as a result of the rods 10 and 81 contacting the opposite faces of disc 16. Thus there is established the parallel relation required between the planes of the faces of cap 16 and disc 14 in accordance with the parallel relation existing between the plate 82 and the end faces of rods 10' and 81 and the longitudinal dimension between these plane faces as determined by the longitudinal dimension between the plate 82 and the end of rod 81 which is accurately adjusted by the micrometer setting. Further motion of the foot treadle will cause the upper electrode to move downwardly and bear upon the cap in the position shown at 24 and initiate a welding current impulse thereby forming a weld between cap 16 and the tube 12 in the location at which the electrode contacts the cap. When the welding current flow is completed the operator will release the foot treadle, raising the electrode from the cap, raising the operating arm 44 and operating the ratchet to cause a 90 revolution of the member 32 of the tube, disc and cap assembly as has been hereinbefore reviewed.

The operator will operate the foot treadle four times producing four welds spaced around the cap and will then release the treadle to an extreme forward position, again moving member 38 to the right to a position providing the clearance required for the removal of the welded assembly and the insertion of an assembly to be welded.

What I claim and desire to protect by Letters Patent is:

1. Apparatus for welding a member to a tube in accurate axial relationship to an element mounted on said tube comprising an elongated support on which said tube and element mounted thereon and said member may be mounted, a welding electrode movable transversely to the axis of said support, gauging means engageable with said element and with said member to fix their axial relationship, and means for bringing said electrode into contact with said member to effect welding thereof to said tube.

2. Apparatus for welding a member to a tube in accurate axial relationship to an element mounted on said tube with planes of said member and element accurately parallel comprising an elongated support on which said tube and element mounted thereon and said member may be mounted, a welding electrode movable transversely to the axis of said support, gauging means engageable with said element and with said member to fix their axial relationship, and means for bringing said electrode into contact with said member to effect welding thereof to said tube.

3. Apparatus for welding a member to a tube in accurate axial relationship to an element mounted on said tube comprising an elongated support on whichsaid tube and element mounted thereon and said member may be mounted, a welding electrode movable transversely to the axis of said support, gauging means engageable with said element and with said member to fix their axial relationship, means for bringing said electrode into contact with said member to effect welding thereof to said tube, and means for rotating said tube and member to successive welding positions with respect to said electrode.

4. Apparatus for welding a member to a tube in accurate axial relationship to an element mounted on said tube comprising an elongated support on which said tube and element mounted thereon and said member may be mounted, a welding electrode movable transversely to the axis of said support, gauging means including a fixed member and an adjustable member, said members having parallel surfaces, one of said surfaces being engageable with said element and the other being engageable with said member to fix their axial relationship, and means for bringing said electrode into contact with said member to effect welding thereof to said tube.

5. Apparatus for welding a member to a tube in accurate axial relationship to an element mounted on said tube with planes of said member and element accurately parallel comprising an elongated support on which said tube and element mounted thereon and said member may be mounted, a welding electrode movable transversely to the axis of said support, gauging means including a fixed member and an adjustable member, said members having parallel surfaces, one of said surfaces being engageable with said element and the other being engageable with said member to fix their axial relationship, and means for bringing said electrode into contact with said member to effect welding thereof to said tube.

6. Apparatus for welding a member to a tube in accurate axial relationship to an element mounted on said tube comprising an elongated support on which said tube and element mounted thereon and said member may be mounted, a welding electrode movable transversely to the axis of said support, gauging means including a fixed member and an adjustable member, said members having parallel surfaces, one of said surfaces being engageable with said element and the other being engageable with said member to fix their axial relationship, means for bringing said electrode into contact with said member to effect welding thereof to said tube, and means for rotating said tube and member to successive welding positions with respect to said electrode.

PRICE L. REED.

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

UNITED STATES PATENTS Number Name Date 1,008,628 Brown Nov. 14, 1911 1,703,588 Meadowcraft Feb. 26, 1929 2,393,719 Stull Jan. 29, 1946 2,451,169 May et a1 Oct. 12, 1948

Images