US 3587148 A
Description (OCR text may contain errors)
United States Patent Inventor Dale V. Henry Basking Ridge, NJ. 787,382
Dec. 27, 1968 June 28, 197 1 RC A Corporation Appl. No. Filed Patented Assignee METHOD OF ASSEMBLY OF ELECTRON TUBES 2 Claims, 7 Drawing Figs.
Primary Examiner-John F. Campbell Assistant Examiner-Richard Bernard Lazarus Attorney-G. H. Bruestle ABSTRACT: A plurality of elongated tubular electron tube electrodes are disposed into nested relationship on a jig with both their leading and trailing ends being disposed relatively randomly with respect to one another. The trailing ends are gathered into a predetermined array and a first spacer plate is mounted thereon to fix the orientation of these ends. The electrodes are then removed from the jig, inverted, and mounted on a jig with the fixed ends closest to the jig and the other ends projecting therefrom. The projecting ends are then gathered and a second spacer plate is mounted thereon to fix their orientation.
METHOD OF ASSEMBLY OF ELECTRON TUBES BACKGROUND OFTl-IE INVENTION This invention relates to the assembly of electron tubes.
In the fabrication of certain types of electron tubes, it is the practice to mount a first electrode spacer plate on a jig, mount a plurality of elongated tubular electrodes on the jig by threading the leading ends of the electrodes through openings through the spacer plate, gather together the opposite or trailing ends of the electrodes between the jaws of combing tools to dispose these ends in preselected relation to one another, and mount a second spacer plate onto these ends.
An advantage of this method of assembly is that by threading the leading ends of the electrodes through the first spacer plate openings, a subassembly is provided in which the electrodes are, at least partially, mutually self-supporting and accurately disposed with respect to one another. Indeed, in some instances, the leading ends extending beyond the spacer plate are clamped rigidly in place by suitable clamping means. See, for example, US. Pat. No. 2,644,998, issued July 14, I953. The purpose of fixing the leading ends is to aid in the subsequent assembly of the second spacer plate.
A problem with this prior art method is that it is difficult and tedious to thread the leading ends of the electrodes through the first spacer plate openings, especially in those instances where the electrodes are numerous, small, and fragile, and the openings are tight fitting. Further, the threading operation often results in damage to the fragile electrodes.
SUMMARY OF THE INVENTION A method of assembling electron tubes comprising disposing a plurality of elongated tubular electrodes into nested relationship on a jig, one set of ends of the electrodes being engaged with a portion of the jig and the opposite set of ends of the electrodes projecting from the jig, the various electrode ends of each set being disposed relatively randomly with respect to one another, gathering together the projecting ends of the electrodes into a predetermined array and mounting a first spacer plate onto the gathered ends to fix the orientation of these ends, disposing the assembly of electrodes on a jig with the unfixed ends of the electrodes projecting therefrom, and gathering the projecting ends of the electrodes and mounting a second spacer plate thereon.
DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of an electron tube cage, partly broken away, assembled in accordance with the present invention;
FIG. 2 is a section along line 2-2 of FIG. I;
FIG. 3 is a front elevation of an apparatus for practicing the present invention;
FIG. 4 is a plan view of the apparatus shown in FIG. 3;
FIG. 5 is a side elevation of the apparatus shown in FIGS. 3 and 4, parts thereof being omitted for clarity, with electrodes of the cage shown in FIGS. 1 and 2 mounted on the apparatus;
FIG. 6 is a front view of the apparatus illustrating the gathering of the electrodes mounted thereon, some of the electrodes being partly broken away; and
FIG. 7 is a side view of the apparatus illustrating the remounting of the electrodes thereon.
DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION With reference to FIGS. I and 2, an electron tube cage 10 is shown. The cage 10 is for use in a ,triode electron tube, such as an RCA 684. Details of the mounting of the cage 10 on a stern, and the enclosing of the cage-stem assembly in an envelope are well known, and are not disclosed herein.
The cage 10 comprises electrodes of known type, e.g., elongated tubular cathode 12, grid 14, and anode l6 electrodes. Opposite ends of the electrodes extend through openings through a pair of spacer plates 18 and 20, of mica, for example, which fix the relative positioning of the electrodes.
In the assembly of the cage l0, ajig 24, and a pair of combing jaws 26 and 28, as shown in FIGS. 3 and 4, are used. The jig 24 comprises a block 30 having an upper surface 32 including an elongated V slot 34 therein, and an upstanding mandrel 36. The combing jaws 26 and 28 have a pair of opposed edges 38, each edge being provided with a series of V grooves 40 for gathering and positioning the ends of the electrodes. Means, not shown, are provided for advancing the jaws 26 and 28 towards one another, into abutting relation, as shown in FIG. 6, and for retracting the jaws, as shown in FIG. 4. Combing jaws of the type shown, and the use of such jaws in the gathering and orienting of electrode ends, are known.
In the practice of the method of the present invention, the grid 14, cathode l2, and anode I6 electrodes are successively dropped, in the order named, onto the mandrel 36 and around one another to provide a nested assembly 45 of electrodes, as shown in FIG. 5. At this time, neither spacer plate I8 nor 20 is mounted on the assembly 45. As shown, the electrodes are maintained in vertical orientation by being disposed about the mandrel 36 and one another. The leading ends 42, 44, and 46 of the cathode llZ, grid l4, and anode I6 electrodes, respectively, fit loosely within the slot 34, and are thus in relatively random disposition with respect to one another. The use of the slot 34, while not essential, is advantageous in that it provides some relative positioning of the electrodes while not adding to the difficulty of loading the electrodes onto the jig 24, the electrode ends being self-centering, in one lateral dimension and the vertical dimension, within the slot 34.
Depending upon the structure of the particular electrode cage being assembled, various other means, such as the use of other or additional mandrels, or recesses in the jig of various configurations for receiving various ones of the electrode ends, can be used to receive and maintain the electrodes in upright relation on the jig.
In the formation of the electrode assembly 45, to the point described, little efiort or skill is required on the part of the operator. This greatly simplifies the assembly operation, in comparison with the prior art method, thus increasing the rate of assembly of the electrode cages while greatly reducing the possibility of damage to the electrodes.
Thereafter, the combing jaws 26 and 28 are advanced towards one another to gather into the jaw grooves 40 the trailing ends 52, 54, and 56 of the cathode 12, grid I4, and anode t6 electrodes, respectively, projecting from the jig to accurately position these electrode ends relative to one another, as shown in FIG. 6. The spacer plate 18 is then mounted on the gathered and accurately positioned electrode ends.
It is to be noted that in spite of the fact that the leading ends 42, 44, and 46 of the electrodes are not held in fixed, accurate relation to one another, as in the prior art method, no difficulty is encountered in gathering the trailing electrode ends 52, 54, and 56, using standard combing tools, or in mounting the spacer plate 18 onto the gathered ends without damage to the electrodes.
The combing jaws 26 and 28 are retracted, and the spacer plate I8 is advanced further along the electrode ends. The electrode assembly 45 is then removed from the jig 24, in verted, and remounted on the jig 24 with the spacer plate 18 resting on the surface 32 of the jig, and the now fixed electrode ends 52, 54, and 56 extending into the slot 34, as shown in FIG. 7.
In the usual instance, the length of the extending ends of the electrodes on opposite sides of the cage 10 are not equal, in which case it is preferably to remount the assembly on a jig similar to the jig 24 herein illustrated, but having a slot 34, or other recesses, of proper depth to receive the electrode ends extending beyond the spacer plate I8.
In one embodiment, not illustrated, the jig is mounted for rotation about a horizontal axis and, upon removal of the partially completed cage assembly 45 from the jig, the jig is rotated The bottom portion of the jig, provided with a suitable slot, or recesses, then serves as the new jig. Because one set of electrode ends are now fixed in place by the spacer plate 18, a mandrel is not required for the remounting of the electrode assembly, thus speeding-up the remounting operatron.
Having remounted the electrode assembly 45 on the jig 24, the combing jaws 26 and 28 are again advanced to gather and orient the ends 42, 44, and 46 of the electrodes, whereupon the spacer plate is mounted onto these ends to provide the completed cage 10.
l. A method ofassembling an electron tube comprising:
disposing a plurality of elongated tubular electrodes in nested relationship on a jig, one set of adjacent ends of said electrodes being engaged with a portion of said jig and the opposite set of adjacent ends of said electrodes projecting from said portion, the various electrode ends of each set being disposed relatively randomly with respect to one another;
gathering together said opposite set of adjacent ends into a predetermined array while leaving the ends of said one set of adjacent ends in random disposition, and mounting a spacer plate onto said opposite set of adjacent ends to fix them in said array; thereafter disengaging said one set of adjacent ends from said jig and disposing the assembly of electrodes on a jig with said one set of ends projecting therefrom; and
thereafter gathering said one set of adjacent ends into preselected array and mounting a spacer plate on said one set ofadjacent ends for fixing them in said array.
2. A method of assembling an electron tube as in claim 1 wherein said step of disposing said electrodes in nested relationship comprises:
guiding a first elongated tubular electrode onto an elongated mandrel extending upwardly from ajig and disposing the leading end of said electrode in loose fit within a recess in said jig; and
successively guiding further elongated tubular electrodes onto said first electrode and disposing the leading ends thereof in loose fit within a recess in said jig.