US1768698A - Thermionic device - Google Patents

Description

July 1, 1930. 5. J. LANE THERMIONIC DEVICE Filed F'b. 12, 1925 2 Sheets-Sheet 1 //v l/E/V 7-0;?

k 7" TOR N E July 1, 1930.

5. J. .LANE 1,768,698

THERMIONIC DEVICE Filed Feb. 12, 1925 2 Sheets-Sheet 2 4? TORNE 7" Patented July 1, 1930 .PATEN'F OFFICE storm! .1. mm 01? mm, NEW You 'rnmromc nnvrcn Application -flled February 12, 1925. Serial No. 8,722.

My invention relates to thermionic devices for the transmission and reception of radiant energy.

In the present thermionic devices of the audion type, as exemplified in the well known radiotrons of the W. D. & U. V. type, the leads from the plate, grid and filament extend from the interior of the tube for a considerable distance to the contact points on the base in close proximity and substantially parallel to each other. Audions having their leads arranged in this manner may be successfully used for the reception of broadcasting upon comparatively long wave lengths and low frequencies but are wholly unadapted for the reception of waves transmitted at very high frequencies and correspondingly short wave lengths. This is due to the inherent capacity in the tube itself, resulting partially from the arrangement of the tube elements themselves, and partially from the arrangement of the leads which extend from the tube elements to the contact points.

' termed the capacity'jcoupling in the pres-- arrangement of. the contact .fsprings in the present type of socket which comprise comparatively largeareas of metal in close proxlmity.

I find that while the present type of tube is not adapted, nor can it be used in its present form for the reception of signals transmitted upon an extremely short wave length, very successful results are attained by removing the base of any of the present tubes and separating the leads as widely as possible. While the removal of the base and the divergence of the leads produces satisfactory results, such a tube is diificult to mount and connect in a radio receiving apparatus. My invention therefore contemplates not only a new form of base for a thermionic device, in which the leads may be separated as widely as possible and in which they are arranged in non-parallel relation, but also a socket adapted to receive my new form of base and m which conductors will continue to diverge.

It is wellknown that in the present form of tube, the prong leads extending through the base of the tube do not make a very satisfactory contact withthe leads extending from the socket. Therefore, another ob'ect ofmy invention is to provide a combine tube and socket in which the electrical contacts will be very positive, will be made with a wiping motion which will tend to keep the surface of the contacts always clean, and in which contacts through solder will be eliminated.

With these objects in view my invention resides in the new form of base for a thermionic device in which the leads from the tube are widely separated and disposed in nonparallel directions, and in the new form of socket having widely separated and "diverging leads, and in the novel manner in which the electrical conne'ction' is madebetween the leads from the tub in. the sockets In the draw1ng. c, Fig. 1 is" a vertical one species of my tube'and base;

Fig. 2 is an outsideielevation of the eridian sectioniof 'e'ele ents andjt-he species of my tube and b e," c

Fig. 3 is an enlarged fr gmentary section.

of the base of this species illustrating the p manner in which the leads are connected to; 1

the contact points 4 is a plan i -1 a Socket for specles; Fig. 5 is a front elevation of the socket in which a portion thereof is broken away for the purpose of illustrating the interior 'con-I struction thereof;

Fig. 6 is a fragmentary section of this base and socket showing the manner in which they co-operate, with the base partially inserted in the socket;

Fig. 7 is similar to Fig. 6 and illustrates the manner in which the spring contact in the socket is deflected when the base is pushed down into the socket;

Fig. 8 is a verticalmeridian section of the preferred form of my tube and base;

. Fig. 9 is an outside elevation of the preferred form;

Fig. 10 is a plan view of my preferred form of socket;

Fig. 11 is a front elevation of-my preferred form of socket in which a portion thereof is broken away for the purpose of illustrating the interior construction thereof.

Fig. 12 is a fragmentary section of a preferred form of envelope for my tube which extends only a short distance below the glass press which seals the leads.

In the drawing, 1, represents the glass envelope inclosing the tube elements. 2, represents the press through which extends the plate lead, 3, the grid lead, 4, and the filament leads 5 and 6. 7, represents the cup-hke base into which the glass envelope, 1, is inserted and secured by means of cement, 8. This base is preferably of bakelite but may be made of any suitable material having a like high dielectric resistance. The base, 7, about its circumference, is provided with four recesses 9, 90 degrees apart. Inserted in these recesses are the thin metal contact cups or linings 10, to which are soldered the four leads rom the tube elements. The metal linings, 10, are formed of brass strips bent as shown in Fig. 3, to provide a small recess in the center thereof and having a small hole therethrou h in the center of the bottom of the recess t hrou h which the respective leads are inserted anfsecurcd by means of a drop of solder 11 (see Fig. 3). Referring to Fig. 3, it will be noted that the ends of the linings, 10, do not extend to the exterior surface of the base but that a small portion, 12, of the insulating material is left to provide a means of retaining the lining in place. The linings, 10, may, if desired, be molded in place, or, the recesses, 9, may be molded in the base and linings, 10 snap (1 into place after the base is complete Immediately below each of the recesses, 9, and extending to the bottom of the base, 7, is a recess, 13, having its inner face, 14, inclined as shown for a purpose which will be apparent as the description proceeds.

Referring to Figs. 4 and 5, my socket comprises an integral unit of bakelite or other material havlng a like high dielectric strength. The socket is provided with a base, 15, and a hollow cylindrical portion, 16, adapted to receive the base, 7, of the tube. The cylindrical portion, 16, in the form of base shown in Fig. 4, is provided with four recesses, 17, ninety degrees apart, from which project the resilient contacts, 18. These contacts are preferably of bronze or other resilient material of good conductivity, and bent to the configuration shown which is vsuch that they recede from the cylindrical portion, 16, in diverging directions. The contacts, 18, extend from the interior of the cylindrical portion, 16, to the exterior, t rough the openings 19. One of these openings is shown in section in Fig. 5. The contacts, 18, are secured to the base, 15, b means of the screws, 20, and nuts, 21 (see ig. 5). The nuts, 21, are countersunk into the base, 15, so that the tops thereof are substantially flush with the top (if the base, 15. The portions of the screws, 20, which extend above the nuts, 21 receive the knurled nuts, 22, to form binding post for connections. The contacts, 18, may extend beyond the base, 15, as shown, and may have their ends, 23, bent into cylindrical shape for the purpose of making soldered connections here if desired.

When the tube is inserted in the socket as shown in Fig. 6, the spring contacts, 18, enter the recesses, 13, on the base of the tube as shown. It will be noted from an examination of Fig. 6, that the back, 14, of the recess, 13, is substantially tangential to the curve of the spring contact 18. Referring to Fig. 5 it will be noted that there is a slight space, 24, between the bottom of the recess, 17 and the contact, 18, when the contact is in its normal unstressed condition. Referring to Fig. 6 it will be noted that as the base, 17, is inserted in the socket the contact, 18, is forced down against the bottom of the recess, 17. As the tube is pushed down solidly in the socket as shown in Fig. 7, the contact, 18, is deflected upwardly and outwardly, so that finally, when the tube is pushed completely info the socket, the contacts, 18, will snap into the metal lined recesses, 10, of the base, 7, thus providing a positive and eflicient electrical contact. Bearing in mind that one of the important features of my device is to provide a tube and socket having a very small inherent capacity, the contacts, 18, are so shaped that they are disposed in diverging non-parallel relation to each other.

The preferred forms of my tube and socket are shown in Figs. 8, 9, 10, 11 and 12. In my preferred form of base the leads from the tube elements diverge as soon as possible after leaving the glass press, 2, and are carried around the lower edge of the glass envelope in the same manner as shown in Fig. 1. n this preferred form of base instead of providing recesses therein as shown in Fi 1, I provide projections, 25, of substantia ly the same construction as now used in the art but which in present practice extend through the bottom of the base instead of the side. These radial projecting pins are merely hollow tubes of brass or similar material provided with collars, 26, which are coun tersunk in the exterior of the base, and are secured in the base by upsetting the inner ends as shown at 27 The leads from the tube elements are pulled through the tubes, 25, and secured therein by a small drop of solder, 28, at the exterior end.

The cylindrical portion, 16, of the socket shown in Fig. 10 is provided with radial recesses, 28, ninety degrees apart, and adapted to receive the projecting contacts, 25, of the base, 7. The lower parts of the recesses 28, are laterally enlarged as shown at 29, in Fig. 11, for the purpose of receiving the clip, 30, on the contacts, 31. The contacts, 31, are

preferably of bronze or other resilient ma- 7 .terial andcompr-isea flat portion, 32, extending from the interior to the exterior of the socket. and have the clip, 30, formed .on the interior end thereof. The normal internal diameter of the clip, 30, is somewhat less'than the diameter of the pins, 25,- so that when the tube is inserted in the socket the pins, 25, may be snapped into the clips, 30, to form a positive and eflicient electrical contact. The contacts, 31, like the contacts, 18, are recessed into the base, 15, and secured thereto by screws, 20, and nuts, 21. The upwardly projecting portion of the screws, 20, receive the knurled nuts, 22, to form binding posts. The exterior ends of the contacts, 31, may be extended beyond the base, 15, if desired, and bent into cylindrical shape for the purpose of making asoldered connection here.

In order to insure that the tube cannot be inserted into the socket except in the correct position, I provide the usual pin, 33, projecting from the base of the tube and adapted to be received in the recess, 34, in the socket.

Figs. 1. and 8 illustrate the application of my invention to the present form of tube in which the portion of the glass, 35,.is carried for a considerable distance below the press, 2, before it is bent upwardly to form the envelope proper. This results in confim'n the leads in close proximity to each other or a greater distance than is necessary, thereby increasing the capacity coupling of the tube. In my preferred form, illustrated in Fig. 12, the bottom, 36, of the envelope does not extend any appreciable distance below the press, 2, so that the leads may be splayed immediately after leaving the press and thus elfect a considerable reduction in capacity. 7 a

While I have illustrated several ways in which the broad features of my invention may be embodied in a ble device, it is obvious that the wide separation and continued divergence of the leads may be effected by other constructions differing somewhat in detail from those here shown, but which are nevertheless within the scope of my invention as defined by the appended claim.

It is to be understood also, that the terms which I have used in 'describin my invention are terms of description an not limitation, and that while I have illustrated and described a tube having only four widely separated element leads, it is obvious that my invention is particularly ada ted for use in connection with thermionic devices having a greater number of elements spondingly greater number of leads extendin therefrom.

hat I claim is- A thermionic device comprising an envelope containing a plate and grid and having a reentrant portlon therein, a base on said encommercially practicavelope surrounding the reentrant portion and having electrical terminals on the sides thereof, and electrical conductors extending from quencie's.

SIDNEY J. LANE.

and a corre-

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