US3183577A - Apparatus for assembling an electron tube cage - Google Patents

Description

P. R. SMITH May 18, 1965 APPARATUS FOR ASSEMBLING AN ELECTRON TUBE CAGE Filed July 1, 1960 4 Sheets-Sheet l INVENTOR. 5340.4 KW/n/ B 0 TTU/F/VE) =1 @II IIII P. R. SMITH May 18, 1965 APPARATUS FOR ASSEMBLING AN ELECTRON TUBE CAGE Filed July 1. 1960 4 Sheets-Sheet 2 INVENTIOR. ff la; KIM/7H Armewzr P. R. SMITH May 18, 1965 APPARATUS FOR ASSEMBLI'NG AN ELECTRON TUBE CAGE Filed July 1, 1960 4 Sheets-Sheet 3 nvmvron. PAUL KIM/TH BY wfl m Arron/z) May 18, 1965 P. R. SMITH 3,133,577

APPARATUS FOR ASSEMBLING AN ELECTRON TUBE CAGE Filed July 1, 1960 4 Sheets-Sheet 4- INV EN TOR.

1 PAUL A. .fM/rH ygiir United States Patent 3,183,577 APPARATUS FOR ASSENELING AN ELECTRON TUBE CAGE Paul Russell Smith, Whippany, N..l., assignor to Radio Corporation of America, a corporation of Delaware Filed July 1, 1960, Ser. No. 40,421 1 Claim. (Cl. 29-2519) This invention relates to the art of assembling electron tube elements, and particularly concerns an improved apparatus for and method of assembly electron tube elements in an electron cage.

In one method of assembling vacuum tube elements between an upper and lower insulating wafer, usually of mica, there is used a jig comprising a depressed portion formed to fit the lower wafer and having a central upstanding mandrel. In assembling elements on the jig, the lower wafer is threaded over the mandrel and moved into the depressed portion of the jig, a cathode is threaded over the mandrel concentrically therewith, and one or more grids and an anode are positioned vertically with the lower end portions of the grid support wires, or grid side rods, and ears on the anode extending through openings in the aforementioned lower wafer. In preparation for the next step of mounting the upper mica, it becomes necessary to position the grids so that the upper ends of the side rods thereof will extend through appropriate openings or holes in the upper wafer when the upper wafer is later applied. Such positioning of the grid side rods is normally done by locating tools engaging said side rods and by moving the positioning or locating tools to a locating position. The locating tools usually comprise slide plates having complementary teeth which engage the upper end portions of the grid support wires and the upper ears on the anode, as the locating tools move towards each other, thereby to push laterally the grid support wires and the anode ears into their final positions. If the grid support wires are laterally too far out of proper position for the grid locating tools to engage the grid support wires, the teeth on the grid locating tools cannot properly locate the support wires, and, in fact, by contact of a support wire with the wrong side of a locating tooth, a grid support wire may be crushed or bent, or pushed in the wrong direction.

It is an object of this invention to provide an improved method of and apparatus for assembling electron tube parts to form an electrode cage.

Another object is to provide a means for prepositioning the grid support wires before a locating tool comes into contact therewith, to insure that the grid support wires are positioned in a region where the locating tool may finally position the grid wires.

It is a further object to provide means for removing a prepositioning means from the field of operation of a locating tool when the pre-positioning means has performed its function.

The foregoing objects are accomplished by a novel apparatus for and method of assembling one or more elements or electrodes in an electrode cage, particularly the grid electrodes in a mount assembly.

'Thus, the electrode or element to be processed by the apparatus and method has transversely spaced end portions of different lengths. The apparatus includes a prepositi-oning slide having notches with diverging edges in the forward end thereof and which is adapted to engage the longer of the end portions referred to. The prepositioning slide or plate is movable toward the electrode in a direction more or less perpendicular to the length thereof, and in such a manner that the edges of a notch in the pre-positioning plate contacts the longer electrode end portion in a plane beyond or higher than the end of the shorter electrode end portion. As the longer electrode end portion moves along the edges of the notch, the entire electrode is moved in a direction generally perpendicular to the direction of motion of the pro-positioning plate, to a location where a locating tool takes over the final positioning of the grids. I

When the pre-positioning slide or plate has performed its function, and lies in the higher plane aforementioned, it obstructs further steps in the assembly of the tube cage. Means are therefore provided for moving the pre-positioning slide out of the way to permit the upper wafer to be applied to the tube cage.

This invention may be best understood in connection with the drawings forming a part of this application, and in which:

FIG. 1 shows a partially assembled vacuum tube cage in perspective mounted on a jig and illustrates an electrode structure to be assembled by apparatus made according to the invention;

FIG. 2 is a side elevation partly in section of a cage assembling machine and shows the positioning and prepositioning means according to the invention;

FIG. 3 is a sectional view along line 3-3 of FIG. 2;

FIG. 4 is a plan view of an electrode pre-positioning means in relation to an electrode positioning means;

FIG. 5 is a section, partly broken away, along line 55 of FIG. 4.

FIG. 6 shows an end elevation of the device of FIG. 4; and,

FIG. 7 shows the shape of the edges of the positioning and pre-positioning means and their positions relative to a work piece such as an electrode having end portions which are too far out of final position to be positioned properly by the locating or positioning tool alone.

A general discussion of this invention follows with reference particularly to FIG. 1.

In assembling an electron tube cage comprising an upper and a lower insulating wafer between which a complement of electrodes is supported, several operations are employed. The lower wafer 10 is first mounted in jig 12 and the electrodes comprising the cage are mounted on the lower wafer 10, the cathode sleeve 14 being placed over a mandrel (not shown) forming part of the jig 12. In the example being described, the electrodes in addition to the cathode 14 comprise an anode 20, a control grid 16 and a screen grid 18. The control grid 16, the screen grid 18 and the anode 20 are substantially concentrically arranged about the cathode sleeve 14 with their lower end portions or ears (not shown) extending through holes in the said lower wafer 10. The upper wafer 22 is then applied over the upper end portions of the grid support wires 28, 42, 30 and 44 and the upper cars 21, 21 of the anode 20. The holes in the wafer 22 are very accurately placed to assure proper spacing of the electrodes in the completed tube. To make it possible to mount the upper wafer over the tube electrode ends and ears, the electrodes must be properly spaced so that their end portions and ears may be disposed in registry with the holes in the wafer. Absence of such registry would make it impossible to apply the upper wafer and push it to its final or home position. In a method of positioning vacuum tube electrodes preparatory to mounting the upper wafer thereon, a pair of locating tools 24 and 2.6 (see FIG. 7) are caused to slide towards each other in a plane such that the cooperating teeth or notches on the inner or adjacent edges of the locating tools 24 and 26 position and hold the upper ends of the grid support wires and the anode ears in registry with the holes in the upper wafer. The upper wafer is then pushed down until the said upper ends or ears enter the holes in the wafer. The positioning tools then move away from the grid support wires and the upper wafer is pushed home to form acage assembly. The

home position of the upper wafer is in a plane below the plane in which the locating tools move. Again, the locating tools are moved towards each other, but just far enough so that the inner edge portions thereof overlie the upper wafer, and the upper wafer applying means is withdrawn, the locating tools now acting as a stripper.

If, in the above-mentioned method, the grids are placed in a jig too far out of a proper position, the end portions of the support wires thereof may contact the teeth on the locating tools in such manner as to push the wires further out of the proper position or even to crush or bend them. For example, considering FIG. 7'with' the pie-positioning slide 36 omitted, it will be noted that grid support wire end portion 30 is disposed to a side of the tooth 32 such that it will be pushed away from its proper position by the tooth 32 when the grid locating tool 26 moves to the left. Similarly, grid support wire end portion 28 is improperly positioned with respect to the tip of the tooth 34 and would be crushed or bent thereby as the tools 26 and 24 move towards each other.

To bring those electrodes which are too far out of position to be properly positioned by the positioning slides 24 and 26 into the region where the positioning slides 24 and 26 can properly position them, there is provided according. to this invention a pre-positioning tool 36, which has relatively large notches 38 and 40 in the forward end thereof is provided. The pre-positioning tool 36 is slidable towards the grid support wire end portions 28 and 30 in such manner that the edges of the said notches 38 and 40 contact the grid support wire end portions 28 and 30 and move them 'in a proper direction so that the locating or positioning tools can take over and perform the final positioning.

Since the grid elements are relatively small in diameter, the two support wires thereof are closely spaced. If separate notches were provided in the forward edge of the pre-positioning tool 36for each grid support wire, the pro-positioning tool notches would become as numerous as, andtherefore a s'small as, the notches in the forward edges of the locating tools 24 and 26. In that case the pre-positioning tool would have the drawback of the locating tool as discussed above. There is therefore provided, according to this invention, only one notch in the forward edge of the pre-positioning slide 36 for each grid.

For cooperation with this pre-positioning slide 36,

Y grids are provided having a particular structure designed for cooperation therewith. A grid having this particular structure is provided with one support wire longer than all other support wires for that grid. Thus, the grids cornprise a longer grid support wire 28 and 30 (see FIG. 1) and a shorter grid support wire 42 and 44, respectively.

In order to permit the pre-positioning slide 36 to engage only the longer gridsupport wires 28 and '30, the pre-positioning slide is movable in-aplane above the upper ends of the shorter grid support wires 42,44 and below the upper ends of the longer grid support wires 28, 30 as positionedon the jig 12.

In order to permit the pre-positioning tool to have notches 38 and 40 as far apart as possible and still engage the longer grid support wires 28 and 30, the grids are oriented in such positions that the longer grid wires '28 and 30 of the grids 18 and 16, respectively, are spaced a maximum distance apart. That is to say, with short and long grid support wires in a common plane, the short grid wires 42 and 44 and the long grid wires 28 and 30 are disposed in alternate array.

With the tube electrodes in proper positions for the application of the upper wafer 22, the upper wafer 22 is pushed down over the upper end portions of. the electrodes.

Since the pre-positioning slide moves in a plane above the ends of tlie'shorter support-wires and above the anode ears, it obstructs the complete mounting of the upper wafer. To avoid this obstruction, according to the invention, the pre-positioning slide is moved out of the area where the upper wafer is supplied as soon as the slide has 4 performed its function. The pre-positioning slide is therefore movable with respect to the locating tools and means are provided to move the pre -positioning slide out of the area where it will interferewith the fitting of the upper wafer to the anode ears and to all the grid sup port wires, as will be further explained below.

The general environment in which my invention finds utility will be explained in connection with FIG. 2. In this figure, a table 46 having legs 48 and 50 isprovided. An endless chain 54 shown in section runs between guides 56 and Lower guide 56" is fastenedtothe table 46 in any known manner While upper guide 58 is fastened to the table at a position spaced from the lower guide, by bracket '60.- Flanges 62 and 64 on the chain 54 bear against the guides at either side thereof and a pin 66 holds the flanges 62 and 64 as well as the bracket '68 in place on chain 54, The bracket 68supports jig 12 in a vertical position and horizontally displaced from chain 54. The jig 12 runs between jig guide: 70 and jig 'holder 72., The

jig guide 70 is fixed on the table 46 in .a known manner.

The jig holder 72 is spring pressed by means of spring 84 towards jig 12 and the jig holder 72 slides on rods 86 mounted in support means 82 which, in turn, is fastened to the table 46. The jig 12 carries the partially assembled tube cage comprising the lower wafer '10 and the electrode elements including anode 20 shown in FIG. 1. In FIG. 2, only the long grid support Wire 28, which extends beyond the ears 21 on the anode andbeyond the shorter grid support wires, is shown, i

Support 78, mounted on table46, slidably supports slide block 101.2 Support 80, mounted on jig'holder sup port 82, slidably supports slide block 102". The slide blocks 101 'andx102 are at the opposite sides of jig 12. Locating tools 24""and 26' and wafer guides 74 and 76, are mounted respectively on slide blocks 101 and 102 and are directedrtowards each other. The support 78 also supports the pre-positioningtool or means 36 and the operating mechanism therefore, 1 as will be more fully explained below. Also, supported from table 46 is a wafer-supplying andpush-down means generallyindicated at 88. This wafer supplying means comprises a vertical shaft 90 mounted for rotaryand axial movements in bearing 92 which is fixed on table 46 in a'known manner. A horizontal tube 94 is fixed at the top of the vertical shaft .90 as by a fitting 97 and a pick-up head 98 is fixed to the end of the horizontal-tube 94. A vacuumIduct 96 is supplied for having holes 103,103 (FIGURE 3) in the lower face 100 of the pickup head 98. The vacuum causes upper wafer 22'to be held against the said lower face 100. A guide is'supplied for guiding the vertical movement of tube 94, in a suitably angularly oriented position, to pick-up further wafers 22 in reservoir 112 as will be further explained below.

FIG. 3 shows a section of the wafer pick-up head 98 of FIG. 2. In FIG. 3, the indentations or holes 101 provide the necessary clearance for receiving the upper ends of the electrodes comprising the electron tube cage. The duct 96 of FIG. 2 connects with'the holes 103, 103 of the wafer pick-up head of FIG. 3 as, stated above.

Cut-away portions 99, 99 of the wafer pick-up head.

provide clearance for wafer guides 74 and 76 of FIG. 2 and for pre-positioning slide 36 and also forlocating tools 24 and 26. The necessity for these clearances will be evident as this description proceeds.

Means are also provided, as shown in FIG. 2, to move the positioning tools and the pre-positioning slides and the wafer guides as required in the performance of their function. The sliding block 102-"slides in. dove-tail groovesin the upper end of the right-hand support 80. (This is also shown in FIG. 4.) The cam 104, which is mounted for rotation ona pivot fixed to leg 50 of the supporttable, contacts rotary cam follower' 106; on the to slide 102 by pivot pin 120-. The lower end of lever 108, which extends below pivot 116 is fastened to a link 122 by pin 124. The spring 117, which is stretched between table leg 50 and link 122, holds the cam follower 106 against cam 104. The other end of link 122 is pivoted on lever 128 by pin 126. The lever 12% is pivoted at 136 on support 136' fastened to table legs 48 and 50. The upper end of lever 128 is fastened at 132 to link 130, which, in turn, is pivoted at 134 to sliding block 101. The lengths of the levers 108 and 128 and the positions of the pivots thereon are so proportioned that, upon rotation of cam 104, the sliding blocks 101 and 122 and the parts mounted thereon, move towards and away from each other in a similar manner as will be explained below.

Further mechanism comprising the rare-positioning slide 36 is mounted on slide 101. Further mechanism comprising means for moving the slide 36 is mounted partially on slide 101 and partially on support 78. This pre-positioning slide 36 and means for operating it may be best understood by reference to FIGS. 4, 5, and 6. However, its relation to the cam operating means may best be seen in FIG. 2. In this last-named figure, a further earn 140 is mounted to rotate in unison with cam 104 as diagramatically indicated at 141. Cam follower 145 fits in cam groove 140 of cam 138. This cam follower 145 is fastened to the lower end of shaft 142. The shaft 142 is splined in bearing 150 and is thus prevented from rotation with respect to the bearing 150. An arm 144 is fixed at one end thereof to the upper end of shaft 142. The arm 144 has an L-shaped pusher 146 fastened to the other end thereof. As cam 138 rotates, pusher 146 moves up and down in accordance with the shape of the cam track. The operation of pusher 146 will be understood from reference to FIGS. 4, 5 and 6.

As shown in FIGS. 4, 5 and 6, the upper ends of supports 78 and 89 are each made with a dove-tail groove. The right-hand sliding block 102 carries at the lefthand end thereof, a right-hand positioning tool 26 and a right-hand wafer guide 76. The sliding block 102 is fitted into dove-tail slot 152 by a suitable spacer 156. As noted above, right-hand slide 102 is pivoted on link 113 by pin 120. The locating or positioning tool 26 and the wafer guide 76 move with slide 102 and the positioning tool is below and extends to the left of wafer guide 76, as shown in FIGS. 2 and 6.

The left-hand locating or positioning tool 24 and the left-hand wafer guide 74 are mounted on and move with the left-hand sliding block 101. This block slides in a dove-tail groove 154 in left-hand support 78 and is held in place by its spacer 158. As has been noted above, the link 130 is pivoted to the sliding block 101 at 134. Up to this point, the right-hand and the left- hand sliding blocks 101 and 102, respectively, are similar to each other. However, the pro-positioning tool 36 is mounted for movement on left-hand block 101 only and means are provided for moving the pre-positioning tool 36 with respect thereto, as will now be described.

A support piece 160 is fastened to left-hand support '78, a portion of said support piece extending over the slide block 101. A lever 162 is pivoted on said support piece 160 by means of a pin 164. The lever 162 is bifurcated and a link 176 is pivoted between the lower legs of said lever 162 by means of pins 174. The other end of link 176 is pivoted to up-standing ears 178 which are integrally fastened to the left-hand end of the pre-positioning slide 36. The pre-positioning slide 36 sildes through a slot 168 in wafer guide 74. The other end of lever 162 is urged to the left by means of a spring 170. This spring 170 is stretched between anchor post 166 and the said upper end of said lever 162. The anchor post 166 is fixed to the left-hand slide 101. A lever roller 172 is provided in a bifurcation of the lever 162 at the right of the lever pivot 164. The pushing means 146 is positioned so that it cooperates with said roller 172 to move the lever 162 about the pivot 164 against the force of spring 170 when the shaft 142 is moved downward. Pre-positioning tool 36 extends to the right of the positioning and locating tool 24 and further to the right of the mica guide 74 when the action of spring 170 is not opposed. Lever 162 will be moved clockwise when pusher 146 is moved down and thereby pre-positioning tool 36 will be moved to the left. Locating tools 24 and 26 are in the same plane and pre-positioning tool 36 is in a plane parallel to and above the said plane. The right and left-hand wafer guides 74 and 76 are in a plane immediately above the pre-positioning tool 36.

Attention is now directed to FIG. 7, which shows the shapes of the inwardly directed ends of the positioning tools 24 and 26 and the shape of the forward end of the pre-positioning slide 36. The positioning tools 24 and 26 have identical ends. The sides of the teeth thereon cooperate with the ears on the anode and with the ends of the grid support wires to hold them in place for positioning of the upper wafer. The forward end of the pre-positioning means 36 has funnel-shaped notches 38 and 40 thereon for cooperation with the abovementioned long grid wires as explained above.

The operation of the upper wafer installing device, in accordance with this invention, is as follows: The jig 12 is moved by chain 54 to the upper wafer supplying station shown in FIG. 2. This jig has already mounted thereon the lower Wafer 10, the cathode 14, the two grids having the long support wire 28 and 30 and the short support wire 42 and 44, and the anode 20 having ears 21, 21 as shown in FIG. 1. At the moment that the jig is presented to the said upper wafer supplying station, the two sliding blocks 101 and 102, as well as all the parts mounted thereon, are at their maximum distance apart and the pusher 146 is in its highest position, the cams 104 and 138 being counter-clockwise from the position in which they are shown in FIG. 2. When the jig is properly positioned between the jig guide 70 and the jig holder 72, the cams 104 and 138 rotate clockwise to the position shown in FIG. 2. Thereby, the pre-positioning slide 36, which leads the locating slide or tool 24, and which is in a higher plane than the locating tool 24, contacts and moves the longer grid support wires 28 and 30 in a direction generally perpendicular to the direction of motion of the prepositioning slide 36, as may be better understood in connection with FIG. 7. The longer grid support wires, in moving, move their respective grids and their respective shorter grid support wires to a more accurate final position. The ears on the anode and the shorter grid wires do not extend to the plane of the grid pre-positioning tool 36 and they are not contacted by this tool. The sliding blocks 101 and 102 continue inwardly until the positioning tools 24 and 26 are in contact end-to-end as shown in FIG. 2. In this position of the positioning tools 24 and 26, all of the tube elements are finally located by means of the pre-positioning and positioning tools, and the wafer guides 74 and 76 are then apart by a distance substantially equal to the width of wafer. As soon as the locating tools 24 and 26 contact the ears on the anodes and the support wires of the grids, the pre-positioning tool has accomplished its function and must be gotten out of the way to permit the upper wafer pick-up 98 head to supply and position the upper wafer 22. This is accomplished by cam means 133 which draws shaft 142 down by means of cam follower 145, and keeps it down until the end of the cycle. The pusher 146 thereby pushes down on roller 172, shown in FIGS. 4 and 6, and moves pre-positioning slide 36 to the left and out of the way for the rest of the cycle. Then the wafer pick-up head 98 comes down and with the cooperation of the wafer guides 74 and 76, which, if necessary, shift the wafer slightly, positions the upper Wafer 22 over the anode ears and the tube element support wires. At this point, the cams 104 and 138 have moved 180 clockwise to dispose cam track at its head 98.

lowestpoint and cam 104 at its highest point. point in thecycle, the slides 101 and 102 are at'their maximum distanceaparttaking with them the wafer; guides 74 and 7.6 and the locating .to'olsj24 and 26. The wafer pick-up head 98 goes down against the anode 29, and

below the plane of the tools 24 and 26. The cams 3AM and 138 continue to rotate. Shaft 142 is kept'in its lowest position but the positioning tools 24 and 26 are moved inwardly-towards each other in the .next 45 of rotation ofcam 104 by an amount suflicient so that the end portions thereof ioverlie the second'wafer, which, as has been pointed out, is against the top of the anode .20 and below the plane of Slides 24 and 26. Air at atmospheric pressure isrestored tothe air duct 96, and the=waferfeeding head-98 is moved upwards by shaft 90, and the positioning tools 24 and Meeting as stripping means to positively strip the upper wafer from'the Wafer feed head 98. This stripping action prevents the tube cage from being pulled out of the jig 12 by the upward movement of the pick-up The cams 140 and 104 continue to turn clockwise until they are displaced 270 clockwise from the point in which they are shown in FIG. 2, at which'time the slide blocks 101 and .162 are at their maximum distance apart and the shaft 142 is in its upper-most position. At this point the cycle is completed. In the mean time, the wafer supply means 98 turns 90 about shaft 90 and moves downwardly to contact Waters 22 in a Wafer reservoir, not shown. Vacuum is applied 11096 to hold one wafer 22 in the wafer feed head 98, and the wafer supply head 98 rises and turns back to the position shown in FIG. 2.' The means for moving it and for supplying reduced air pressure to it'is not described in detail here. is shown and described in Patent 2,842,832 to Chase et a1., assigned to the assignee of this application. This 3 . holder 72, 84 and 86.

At 'this.

Such a meansv What is claimed is."

Apparatus for orienting electrodes having supporting elements whose lengths are difierentfrom each other comprising: I V

means for supporting the supporting elements of said electrodes in substantially parallel relation with each other, afirstplate having a formed edge for engaging and guiding the longest support elements only of said electrodes to a preliminary position, 7

means for moving said-first plate into engagement with said longest supporting elements,

second and third plate elements on opposite sides of said supporting elements and having formed edges to guide all of said supporting elements to a final position, and

means for moving said second and third plate elements towards one another and into engagement with all of said supporting elements at "a positionbetween said electrode supporting means and said first plate,

said first plate being spaced from said second and third plate elements a distance suchthat r-said first plate element engages said longest supporting elements beyond the ends of the others of said supporting ele- .ments.

References Cited by the Examiner UNITED STATES PATENTS 5/60 Rangabe 2925.13

RICHARD H. EANES, 111., Primary Exaniinef.

THOMAS E. BEALL, LEON PEAR, Examiners.

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