US2275490A - Vacuum tube - Google Patents

Description

March 10, 1942. I A w BARBER 2,275,490

VACUUM TUBE ,Filed Nov. 20, 1959 INVENTOR Patented Mar. 10, 1942 UNITE D STATES FAT E N T O FF! CE 2,275,490 1 VACUUM TUBE. Alfred W. Barber, Flushing, N. Y. ap lication November 20, 1939,. Serial No. 305,222

4 Claims.

The present invention concerns vacuum tube construction and in particular a base and terminal construction which eliminates the use of conventional sockets.

One object of my present invention is to provide a vacuum tube requiring no socket.

Another object is to provide a vacuum tube suited to direct soldering of circuit connectionsto the tube prongs.

Still another object is to provide a simple rigid mounting for the tube.

And still another object is to provide a simple shielding integral with the tube.

These and other objects will be evident from the detailed description of the drawing.

Thermionic vacuum tubes of the type used in radio receivers and sound amplifier in thepast have been provided with prongs attached to leads from the tube elements which are adapted to insertion in a socket to which circuit leads are soldered. I have found it possible to eliminate the socket and at the same time improve the performance of the tube by providing tube prong terminations suitable for direct soldering to the circuit elements. Doing away with the intermediate unsoldered socket contact lowers circuit resistance and inductance and provides a more permanent connection. The base of the tube is formed of a thick piece of glass which provides a, firm support for the tube. in conjunctionwith a simple clamping ring. Shielding is provided by spraying the outside of the tube with metal which contacts the chassis when the tube is clamped in place.

In the drawing:

Fig. 1 shows a cross-section thru a vacuum tube and mounting according to the present invention.

Fig. 2 shows an end-view-of the tube of Fig. 1.

Fig. 3 shows an alternative mounting form.

Fig. 4 shows the base of a tube according to the present invention showing certain circuit elements connected to the tube prongs.

In Fig. 1 is shown a cross-section thru a vacuum tube and mounting according to a preferred form of my present invention. The foundation base plate I for the tube is formed from a circular piece of thick glass in which the tube prongs III are embedded. The lower part of foundation I is formed into a smaller diameter section 5 adapted to fit a circular hole 2 in chassis or subpanel 6. Just below section 5 is an indented section 3 adapted to receive a spring ring 4 for clamping and drawing the tube against chassis 6.

The tube envelope 1 has a uniform diameter approximately equal to the diameter of the upper part of foundation I to which it is welded in the process of manufacture. The outer surface of the tube envelope 1 is covered with sprayed metal to form an electrostatic shield. Shield 8 is extended along foundation I so that it will form a large area contact with chassis 6 when the tube is locked in place. Tube prongs III are formed of single pieces of metal extending thru foundation I. The tube elements I4 are mounted on the inner ends of prongs III by means of stiff spot- Welded leads I3. The outer ends of prongs III are flattened into solder lugs II and maybe pierced at I2 to facilitate connection to circuit elements. The tube may be exhausted thru a central hole I5 in foundation I and sealed off in tubulation I6.

The thickness of foundation I gives it considerable thermal capacity which aids in dissipation of heat generated in soldering wires to lugs I I. However, it is preferable to make foundation I of hard glass to prevent cracking. Prongs are preferably made of metal having a temperature coefficient substantially the same as the glass used for base plate I. The flattened ends II of prongs I0 may be tinned to provide for easy soldering.

In Fig. 2 is shown an end-view of the base of the tube shown in Fig. 1. It shows more clearly the clamping ring 4 at least partly surrounding the narrow portion 5 of base I. It also shows exhaust tubulation I6 and prongs Ill-I I.

In Fig. 3 is shown a modified base I adapted to another method of mounting on subpanel 6. Base I has flanges I1 extending on two sides which are clamped by means of clamps I8 held to subpanel 6 by bolts or rivets I9.

In Fig. 4 is shown the base of a tube according to the present invention showing the mode of connection to various circuit components. Base I is shown clamped by means of spring ring 4 to subpanel 6. The tube prongs II of Figs. 1, 2 and. 3 have been numbered 20, 25, 2B, 30 and 33 in order to distinguish them. A grid control potentiometer 35 having an input lead 36, a grounded lead 31 and a tap point lead 34 feeds grid prong 33 thru lead 34 which is soldered directly to the flattened end of prong 33. Cathode prong 30 is grounded at 32 to subpanel 6 by means of lead 3|. Heater leads 26 and 21 are soldered to prongs 25 and 28. Plate prong 20 is soldered to leads 23 and 2I connecting a load resistor 24 and output coupling condenser 22 respectively.

A rubber Washer 38 may be placed between the flange of base I for shock-proofing as shown in Fig. 3 and the shield coat 8 may be connected to the cathode pin grounded.

One important advantage of the present invention is that the tubes mounted as described above may be turned in any direction to facilitate wiring and shorten leads.

While one form, with a few modifications, of the present invention has been shown and deor to a pin which may be scribed, many modifications may be made within containing embedded therein a plurality of tube terminals and forming an integral part of the tube envelope, a flange on said base for support ing a glass envelope, a channel in said base at least partly encircling said base below said flange, and a circular spring fitting said channel for mounting said tube on a subpanel.

3. In a thermionic device, a thermionic vacuum tube embodying a glass base containing a plurality of tube terminals flattened at their outer ends embedded therein; a tube envelope welded on said glass base, a metal coating covering said envelope and at least a part of said base for shielding said tube, a clamp for holding at least a portion of said coating against a metal subpanel to ground said shield, and a plurality of circuit elements connected directly to said terminals.

4. In a thermionic vacuum tube, a glass base containing embedded therein a plurality of tube terminals and forming an integral part of the tube envelope, a shoulder in said base for supporting said tube against a flat surface and projecting a portion of said base thru an opening in said surface, and means for drawing said shoulder toward said surface to mount said tube over said opening.

ALFRED W. BARBER.

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