US2829941A

US2829941A - Getter flashing

Info

Publication number: US2829941A
Application number: US585444A
Authority: US
Inventors: Paul R Laubscher
Original assignee: Sylvania Electric Products Inc
Current assignee: GTE Sylvania Inc
Priority date: 1956-05-17
Filing date: 1956-05-17
Publication date: 1958-04-08
Anticipated expiration: 1975-04-08

Description

April 8, 1958 P. R. LAUBSCHER GETTER FLASHING Filed May 17, 1956 TO FLASH UNIT CAP TO WIRE GETTER FLASHI INVENTOR PAUL R. LAUBSCHER ATTORNEY SOLDERING UNLOADING' AND LOADING raised ice GETTER FLASHING Paul R. Laubscher, Lock Haven, Pa, assignor to Sylvania Electric Products line, a corporation of Massachusetts The invention relates to getter flashing of exhausted and tipped otf electron tubes while on a machine which solders the top caps to anode lead wires protruding through domed portions of the tubes.

It is an object of the invention, where getter flashing is accomplished after bombardment and tipping off op erations on a tube, to ensure that easy and proper positioning of the unflashed getter holder opposite the flashing coils be attained.

It is a further object that this be done as a final step in some other necessary operation on the tube so as to avoid additional handling of the tubes or a separate machine.

These and other objects will be understood after consideration of the following detailed specification and accompanying drawings in which Fig. 1 is a diagrammatic view of a capping and getter flashing machine.

Fig. 2 is a broken away perspective view of part of the cap to bulb adhering and getter flashing machine, and

Fig. 3 is a modified form of spindle which may be used to orientate a tube for the proper getter flashing action.

In general, the combined machine comprises an indexible turret It) haxing three

decks

12, 14, and 16 at diflerent horizontal levels. Spindles 13, traversing decks l2 and 14, are spring urged upwardly to hold a capped bulb 2d, of the electron tube to be processed, in proper position with respect to the turret and with its bulb part and cap centered by appropriate elements on the upper deck 16, these elements being opposed to the spindles. Each of the caps 22 prior to assembly over the anode lead-in wire 24 has been internally coated with a resin so that the cap would adhere to the top of the bulb when the resin is suitably baked. In the final stages of the machine, the caps are soldered to the anode lead-in wires. Prior to the final stage, the getter is flashed.

Each of the spindles 18 passes through a bushing 26 fast on lowermost deck 12 and through a second bushing 23 fast on mid deck 14. In the bushing 28 there is a screw 30 passing radially through the bushing, in the nature of a key, and extending into a longitudinal key way or slot 37 in the spindle. Thus the spindle while free for reciprocation in the

bushings

26 and 28 will be held against rotation. To urge the spindle to a raised position, it is provided with a collar 34 suitably secured to the spindle against movement with respect thereto, and a compressed coil spring 36 reacts between the bushing 26 and collar 34. The spring will urge the spindle upwardly until a stop collar 38 fast on the spindle engages the under surface of the deck 12 with no bulb on the spindle, or, with a bulb on the spindle, until the dome of the bulb abuts bulb centering and upward movement limiting pins 49 passing horizontally through a metallic bracket 42 mounted in any suitable manner on the top deck 16, these pins being held in adjusted position by locking screws 44. Before baking on, the cap itself is centered by insertion within a suitable opening 46 in a plate 48 fastened in any convenient manner on the bracket 42. The bracket is suitably channeled, as at 50 and 52 to allow flames of baking-on burners 54 to strike the cap to set the resin. The baking-on mechanism per se forms no part of this invention and therefore no further description thereof appears to be necessary.

For the induction getter flashing operation, it is necessary that the tubes be properly orientated with respect to the spindles, and the spindles with respect to the induction coils. It should be understood that in the manufacture of a type of radio tube, the U-shaped metallic supports 56 for the cross bar 58 containing the gettering material are always mounted in the same position in the tube with the cross bar close to the glass bulb. In the case of the type of tube here shown two such getter supports 56 and cross bars 58 are supported within the tube opposite a somewhat cylindrical surface of the bulb. The loops formed by the U-shaped supports and bars must be positioned opposite the getter flashing coils, here indicated as 60 and as, when the turret indexes around to bring the tubes whose getter is to be flashed opposite the coils. To accomplish this result, the upper end of each spindle is provided with an orientating device in the form of a spindle head 6 having a conical surface with an extruding bump 66 for engagement between a wide gap between lead-in pins on a tube, where the tube type has pins arranged equally spaced from one another except for one pair of pins. If desired, the cone may be centrally recessed to accommodate, loosely, the key utilized with some type of tubes.

As an alternative means for securing registration with tubes having central keys, the form of orientating spindle head 68 shown in Fig. 3 may be employed. This head has a central opening '74) and key slot 72 for snugly receiving the key of the tube.

In operation, the operator will apply resin to within a cap 22 and place the cap over the anode wire 24 of a tube. Next, the operator will place the tube on the spindle head while depressing the head against the action of the spring 36, orientate the tube on the head and make the tube erect, as necessary. On release of the tube, the spring will force the tube upwardly with the cap entering the opening 46 and the bulb being stopped by engagement with the bulb dome engaging and bulb centering pins 4d.

After baking the cap on the bulb, the turret is indexed toward unloading stations Whereat the operator removes the tubes. lust before the unloading stations there is provided a cap-to-wire soldering station where automatic mechanism of which the plate '75 forms a part applies heat, flux and solder to the cap and wire to solder the two together. Since this forms no part of the invention, no further description of this mechanism is given. For simplicity of description it may be assumed that conventional hand soldering is employed to solder the cap to the wire. Just prior to the soldering operation, the getter material in the cross bars is flashed. For this purpose, there is provided at each of two stations close to the soldering station a flash coil, such as B or 62 energized when the turret has reached an indexed position. The coils tit and 62 are series connected through hollowwater cooled conductors '73 as is usual in the art, and are energized whenever a switch 74 is closed. This connection between the switch and the coils are not shown since the manner of obtaining high frequency currents in the coils are Well known in the art and form no part of this invention. The switch is closed by reason of movement of plunger 76 carrying a roller '73 when the roller engages a spindle during indexing of the turret or by reason of some equivalent arrangement. The switch is closed during the stationary period of turret indexing.

The openings in the

coils

60 and 62 are of an area sufficient to induce eddy circuits in the loops formed by the support 56 and bar 58 and of a magnitude to preheat the getter containing cross bar 58 at the station opposed to coil 6%) and, at the next station, opposed-to coil 62, to rupture the cross bar and flash the getter on the col-d walls of the bulb. Since, prior to inductive heating of the getter containing loops, only the caps-had been heated for baking the same onto domes of the bulbs, the glass of the bulb opposite the getter containing loops, due to poor heat conductivity of glass, is substantially at room temperature. As a resultwhen the getter is explosively flashed, the getter material itself is condensed on a large area of the adjoining cold glass. Because the glass is cold, none of the getter is re-evaporated from the glass to condense on other surfaces within the tube, such as insulators or electrodes of the mount. As a result, the getter material is retained on the large glass area to ofier a large surface for residual gas absorption.

Having described the invention, new is:

1. In getter flashing apparatus, a reciprocatory spindle biased to move toward a limitative position, means for restraining said spindle against rotation, means on the upper end of the spindle to engage a formation on the base of an electron tube so as to orient the tube with respect to the spindle, said tube having a getter therewithin to be flashed, means opposed to the spindle to engage a tube mounted on the spindle to limit the movement of the spindle, and means, opposed to the getter Within the electron tube, to flash the same.

2. In getter flashing apparatus, an indexible turret carrying circumferentially arranged spindles, each spindle being reciprocative through said turret and biased to move toward a limitative position, means for restraining each spindle against rotation, means on the upper end of the spindle to engage a formation on the base of an electron tube so as to orient the tube With respect to the spindle, said tube having a getter therewithin to be flashed, means opposed to the spindle to engage a tube mounted on the spindle to limit the movement of the spindle, induction coils, opposed to the getter within the electron tube, to flash the same, and means controlled by contact with a spindle by reason of indexing operation of the turret for controlling the current flow to the induction coils.

3. 1n getter flashing apparatus, a reciprocatory spindle biased to move toward a limitative position, means for restraining said spindle against rotation, means on the upper end of the spindle to engage a formation on the base of an electron tube so as to orient the tube with respect to the spindle, said tube having a getter there- Within to be flashed, a support bracket opposed to the spindle having locating pins extending toward each other to engage the top of a tube mounted on the spindle to what is claimed as l limit the movement of the spindle and to center the tube with respect to the axis of the spindle, and means, op posed to the getter within the electron tube, to flash the same.

4. In getter flashing apparatus, a reciprocatory spindle biased to move toward a limitative position, means for restraining said spindle against rotation, means on the upper end of the spindle to engage a formation on the base of an electron tube so as to orient the tube with respect to the spindle, said tube having a getter therewithin to be flashed and an anode cap thereon, a support bracket opposed to the spindle having a perforated plate within which the cap is centered and also locating pins extending toward each other to engage the top of a tube mounted on the spindle to center the cap and tube and limit the movement of the spindle, and means, opposed to the getter within the electron tube, to flash the same.

5. Ingetter flashing apparatus, a vertically reciprocatable spindle biased to move upward, a stop means on the spindle to limit upward movement thereof, means for restraining said spindle against rotation, means on the upper end of the spindle to engage a formation on the base of an electron tube so as to orient the tube with respect to the spindle, said tube having a getter there- Within to be flashed, stationary means above the spindle to engage a tube mounted on the spindle to limit the upward movement of the spindle prior to limitative movement due to the stop means on the spindle, and means, opposed to the getter within the electron tube, to flash the same.

6. In getter flashing apparatus, an indexible horizontal turret carrying peripheral circumferentially arranged spindles, each spindle being biased to move upward through the turret toward a limitative position, means for restraining each said spindle against rotation, means on the upper end of each spindle to engage a formation on the base of an electron tube so as to orient the tube with respect to the spindle, said tube having a getter therewithin to be'flashed, stationary means on the turret above the spindle'to engage a tube mounted on the spindle to limit the movement of the spindle, and a pair of induction coils, one each at two adjacent indexing stations of the turret and opposed to the getter within the electron tube, to flash the same.

References Cited inthe file of this patent UNlTED STATES PATENTS 1,710,428 Key Apr. 23, 1929 1,832,677 Wildeboer Nov. 17, 1931 1,997,694 Morick et al. Apr. 16, 1935 2,337,056 Mathias et a1 Dec. 21, 1943 2,673,784 Snyder Mar. 30, 1954