US3104451A - Assembly apparatus - Google Patents

Description

Sept. 24, 1.963 I G. A. FLODBERG ETAL 4, 5

ASSEMBLY APPARATUS Filed Sept. 8, 1960 2 Sheets-Sheet l VACUUM SOURCE INVENTORS' ROBERT D. CO/iW/N GERH RD A. FL ODBERG BY Q). mm

I A 7'7'0R/VEY p 1.963 G. A. FLODBERG ETAL 3,104,451

ASSEMBLY APPARATUS Filed Sept. 8. 1960 2 Sheets-Sheet 2 INVENTORS ROBERT D. CORWl/V GERHARD A. FLODBE/PG A TTORNEY United States Patent 3,104,451 ASSEMBLY APPARATUS Gerhard A. Flodberg, Concord, and Robert D. Corwin, Framingham, Mass, assignors to Raythe'on Company, Lexington, Mass, a corporation of Delaware Filed Sept. 3, 1960, Ser. No. 54,605 1 Claim. (Cl. 2925.l9)

, The present invention relates generally to the art of fabricating electron discharge tubes, and more particularly to an apparatus for the assembly of multi-electrode vacuum tube structures.

Multi-electrode structures are, at the present state of the art, assembled manually on a fixture. The individual components are placed by hand or with tweezers onto the fixture where they are manually assembled. One disadvantage of the conventional method is that possibility of damage to the electrodes is great, as each electrode must be handled continuously during the assembly operation. Another disadvantage of the conventional method is that great dexterity is required of the operator in order to assemble an acceptable electrode structure. Also, a relatively long training time is required for the operator to reach the level of proficiency necessary to assemble satisfactory electrode structures.

Machines that are presently known to the art for automatic electrode assembly are relatively complex and space consuming. These machines require the constant attention of a trained operator'since, due-to their complexity, they require frequent adjustment, and therefore do not satisfactorily perform their function.

. The present invention provides a relatively simple and compact apparatus for the assembly, either automatically or semi-automatically, of multi-electrode structures. The simplicity of the invention assures long periods of trouble free operation with a minimum of adjustment. Also, the production output of the present invention will far exceed the production rates of current methods.

Little training time is needed since a minimum of operator skill is required to operate the present machine. In the present embodiment of the invention, the operator has merely to place the cathode sleeve over a guide pin, and inspect the completed structure. All other steps in the assembly operation areautomatically performed. A cathode is manually placed on the machine so as to allow the operator to inspect the emissive coating before the cathode is assembled. Another embodiment of this invention could provide an automatic means for feeding the cathode to the machine.

The invention comprises a plurality of fixtures, each fixture including a plurality of electrode holders, the fixtures being attached to a rotatable table which can be moved intermittently. Above each fixture is situated a feeder for supplying each of the several components that make up the electrode structure. Mechanical means are provided for actuating the electrode holders in synchronous relation to the intermittent movement of the table. The intermittent movement of the table causes the fixtures to be successively positioned beneath the several feeders which supply their respective components to the fixture.

The electrode holders comprise a means for holding the bottom mica spacer aligned to receive a plate electrode, a pair of jaws to grasp a plate electrode, and a guide pin to engage a cathode sleeve and accurately position the sleeve within the plate barrel. Means are also provided to supply a top mica spacer and to seatthe electrodes in the mica spacers. Additional means are provided to eject't'ne completed structure. 1

The detailed operation of the invention can be best described With the aid of the drawing wherein:

FIG. 1 is a perspective view of the overall invention,

with some parts shown in section, and some parts exploded for the sake of clarity;

FIG. 2 is a perspective view of the holder means shown generally in FIG. 1; and

FIG. 3 is a perspective view of a portion of the holder in the closed position, with an electrode structure in position.

A circular table 1 is fixed-1y attached to shaft 2, said shaft being rotatably attached to base plate 4. Fixedly attached to the lower extremity of shaft 2 is Geneva wheel 5, and gear 6 which is in mesh with pinions 7 and 8, said pinions being affixed, respectively, to shaits 9 and 10, which are fixedly attached to mica-loading heads 11 and :12. Geneva driver .13 is fixedly attached to shaft 14, said shaft being driven by right-angle drive 15, which is, in turn, driven by shaft 3-1.

Fixedly attached to shaft 31 are drive sprocket 21, and cams 18, 19, and 20 by which synchronization of the movement of the machine are accomplished, the shaft 31 being driven by motor 28 cooperating with sprocket 21 and chain 29.

. Table 1 is indexed by means of Geneva driver 13 and Geneva wheel 5'. As table 1 rotates, mica-loading heads 11 and 12 are rotated .by the cooperation of pinions 7 and 8 with gear 6. Mica-loading heads 1d and 12 are also vertically slidable by means of arms 22 and 23 as will be subsequently explained.

Table .1 is locked, during an indexed stop position, by the engagement of pin 16 with hole 93 in the table, pin 16 being slid-ably operable by the cooperation of hell crank 17 and cam 18, said cam being designed such that pin 16 is retracted from hole 33 each time table 1 is about to rotate. V

Mica-ioading heads 11 and 12 are synchronized with the indexing movement of table 1 by means of carns 19 and 2d, and pinions 7 and 8. The heads are both slid able, by means of arms 22 and 23, and rotatable, by means of pinions 7 and 8. Slidable motion is given to shafts 9 and 10 by the cooperation of dams 19 and 20 with followers 72 and 73 on arms 22 and 23, and rotatable motion is achieved by means of pinions 7 and 8 cooperating with gear 6. Pivots 24 and 25, and sockets 26 and 27 allow both slidable and rotatable movement. The springs 35 and '36, respectively, insure positive vertical movement of shaft-s 9 and 10.

Head 11 comprises two operating areas 32 and 3 3.

A vacuum system is incorporated in head 11 such that there is a vacuum on the operating area 32 above mica magazine 34, while the vacuumis cut off on the operating'area 33 above the nest '46; Thus, operating area 32 picks up by, vacuum a mica spacer from magazine 35%, and operating area 33, having the vacuum cut off, deposits a spacer on nest 46. Head 112 functions identically.

The cams are constructed such that the mica loading heads are lowered during the indexed stop position of table 1, and raised when the table rotates. As table 1 indexes, mica loading heads 11 and 12 are rotated by means of pinions 7 and 8 meshing with gear 6. In the lowered positiomone operating area picks up a mica spacer cfrom the mica magazine and the other operating area drops a mica spacer onto the holder, as previously discussed.

The electrode holding means is shown in more detail in FIG. 2. Base plate 40 is fixedly attached to table, 1. Stop posts 41 and 42 are fixedly attached to base plate 40 so as to engage jaws 43 and 44 when they are lowered. Fixedly attached to the center of base plate 40 is cath ode guide pin 45 which extends through nest 45. Bushlugs 47 and 48 accommodate cylindrical posts 49 and 50 which slidably pass through said bushings and fixedly connect to nestdo. The lower extremities of posts 49 and 59 are fixedly connected to plate 51 to which is rotatably connected cam follower 52.

Jaws 4-3 and 44 are pivotally connected to the upper extremities of posts 49 and 50 by pins 53 and 54. Springs 55 and 56, respectively, urge jaws 43 and 44 into an upward position out of cooperation, adjustable pins 5'7 and 58 on posts 41 and 42 acting respectively as a lower stop for jaws 4 3 and 44, while adjustable screws 59 and 69, which lElIC set respectively in frames 61 and 62, act as an upper stop for said jaws.

It is seen that the holder unit 9% consisting of posts 49 and 50, support 51, nest 46, and jaws 43 and 44 is vertically slidable through bushings 47 and 48. To insure positive vertical slidability, spring 94 is connected between nest 4d and table 1, urging the slidable unit downward against the action of cam 63.

Cam follower 52 rides upon cam 63, said cam having two dwell positions and one peak position, the height of said cam determining the vertical position of the slidable uni-t. During the upper dwell position, jaws 43 and 44 are open and the holder is in a position to receive -a bottom mica spacer 80. As the follower 52 moves to the lower dwell position, posts 49 and 50 move downward causing jaws 43 and 44 to engage pins 57 and 58 thereby causing said jaws to close. With the holder in the lower position, cathodeguide pin 45 is caused to extend above jaws 43 and 44 and is in position to accept cathode 82. Cam follower 52 cooperates with the peak area of cam 63 to drive the holder further upward whereby post 92 engages ejector tab 69 thus uns'eatin-g the completed electrode assembly.

The ejector 64, attached pivotally to plate 46, comprises forks 65 and 66 which lay in slots 67 and 68 of plate 46, and tab 69 which engages post 92 causing said tab 69 to move downward, consequently causing forks 65 and 66 to move out of slots 67 and 68, thereby unseating the completed electrode assembly. The completed structure can then be transferred, by a burst of air or other suitable means, from the holder to a con veyor by which the structure is delivered to the operator for inspection and packing. Alternatively, the completed structure could be ejected to a storage means in which the structures would await inspection at a later time.

Above each electrode holder is suitable means for feeding individual components to the holder in synchronization with the movement of the indexable table. The feeders can be any of the types well known to the art. In the present embodiment, vacuum mica loading'heads 11 and 12 transfer the mica spacers from magazines 34 and 35 to nest 46. The plate electrode 83 is fed to the holder by means of a chute 71, and the cathode 82 is manually placed over guide pin 45, although automatic feed of thecathode could be provided. It is to be understood that the scope of the invention is not to be limited by the aforementioned feeder means, as a variety of alternative means would be obvious to those skilled in the art.

During the first indexed position of table 1, in the assembly sequence, mica loading head 11 places a bottom mica spacer onto plate 46 in such position to allow the plate electrode tabs 84 and to be inserted into said spacer. While table 1 is in the second indexed position, a plate electrode 83 is fed by chute 71 to a position between the jaws 43 that the lower tabs 84 and 85 of plate electrode 83 are aligned with mica spacer 80. When table 1 is in-the third indexed position, cathode 82 is manually placed over guide pin 45 which is extending beyond the top of plate electrode 83. In the fourth indexed position, top mica spacer 81 is placed by mica loading head 12 over pin 45 disposed such that tabs 86' and 87 can be inserted in mica spacer 31; and in this same position the electrodes are seated in the mica spacer by the downward movement of mica loading head'll. In the present embodiment, the fifth position is not used but is provided in the event that an additional electrode is to be added.

As the table indexes into the sixth and last position of the assembly sequence, holder 40 raises in responseto the contours of cam 63 causing pin 45 to recede and also causing jaws 43 and 44 to open due to the disengagement of posts 41 and 4-2 with said jaws, the jaws 43 and 44 acting to the respective urging of springs 55 and 56. The completed electrode assembly 91 is unseated by means of ejector 64 which engages post 92 causing the ejectorto pivot so as to unseat the completed electrode assembly.

Further means, such as an air jet, may be provided whereby the electrode assembly is propelled to an adjacent receptacle. g

In the present embodiment of the invention, 6 fixtures are provided on the rotatable table, although a greater or lesser number may, of course, be used depending number of electrodes to be assembled. a

While what is believed to be a preferred embodiment of the invention has been described, various modifications will occur to those skilled in the art, and can be on the made without departing firom the spirit and scope of the' present invention.

What is claimed is:

An electrode assembly apparatus comprising a rotatably indexable structure carrying a plurality of electrode holding fixtures, means for indexing said structure at spaced stations, said fixtures each comprising a base, a platform movable toward and away from the base in synchronism with indexing of the structure at selected stations, said fixtures each comprising a base, support means on said platform for receiving a mica spacer, a guide pin slidable in the base and extending through the platform and so port means for receiving an electrodethereover, a pair of jaws mounted on the fixture and pivot-ally connected with the platform for movement toward and away from the guide pin and into and out of overlying relation with the platform, means for positioning a top'mica spacer on electrode parts located in the fixtures, and means for ejecting assembled electrodes from the fixtures comprising an ejector positioned within said support means, and a post fixed to the base, the ejector being pivotal adjacent its end nearest the post and having a portion adaptedto engage the post when the platform is raisedfor unseating an electrode assembly from the support means.

References Cited in the file of this patent UNITED STATES PATENTS and 44 and in such disposition Bates 'Nov. 29, 1960f

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