US1976561A - Tube base and socket - Google Patents

Description

Oct. 9, 1934. J, RM N 1,976,561

TUBE BASE AND SOCKET Filed Aug. 16, 1933 2 Sheets-Sheet l INVENTOR JUL I05 H/RMA/V/V ATTORNEY Oct. 9, 1934. J, HIRMANN TUBE BASE AND SOCKET Filed Aug. 16, 1933 2 Sheets-Sheet 2 u m MATHHIHH Patented Oct. 9, 1934 1,976,561 TUBE BASE AND SOCKET Julius Hirmann, Hillside, N. J., assignor to Radio Corporation of America, a corporation of Delaware Application August 16,1933, Serial No. 685,347

5 Claims.

My invention relates to vacuum tubes and the like, and more particularly to bases and sockets of the base thus adding to the overall length of the tube. These tubular contact pins are connected to the electrode elements of the tube by leading-in wires threaded into and soldered to the pins. The conventional socket has spring contacts which engage the contact pins of the base. The socket contacts extend radially out- -ward and are fastened-at their ends or intermefiate their ends to the bottom of the socket by rivets or the like. 7 The socket is inherently large and bulky and extends considerably beyond the outline of the base of the tube. An increase in the number of contact pins on the base decreases the spacing between the pins, increases the tendency for voltage breakdown through the base and greatly increases the difliculty of basing the tube particularly the threading of the leading-in wires into the contact pins.

socket has likewise reached a practical limit because of lack of space and because ofltheincrease in the tendency of :voltage breakdown through the socket. Assembly of the socket due to the number of parts required is likewise made more difficult.

Not only has the practical limit been reached in the number of contacts which can be mounted in a conventional way in tubebases and sockets of conventional size, but tube bases and sockets only about one-half the conventional size must .be made with as many or even more contacts than the bases and socket of conventional size. The

- usual number of conventional contact pins cannot be mounted in the conventional way on the smaller base, yet a corresponding reduction in size of the contact pins will result in pins which are too weak for practical use, which do not have enough contact area and which offer great difficulty in the threading of the leading-in wires into the pins. Furthermore, there is a practical limit in the reduction of the diameter of the contact pins and of the leading-in wires, as the wires must be sufficiently large to carry the necessary current and also stiff enough to thread easily into the pins, which must, of course, have a bore somewhat larger than thewire. n V v A reduction in the size of the conventional socket and its contacts will result in contacts which are The number of contacts which can be accommodated by the conventional too weak for practical use, which do not have sufficient contact area and which increase the difficulty of assembling the socket. It would not be practical to materially reduce the size of con-' tacts in the socket and still have these contacts. properly cooperate with base pins which were not materially less than the conventional size.

The conventional contact pin is in efiect riveted into the base by upsetting or spinning the inner end of the pin over theinside of the bottom of the base. The inner end is thus enlarged and in effect increases the diameter of the pin 'so that more rcomis-required for spacing between the pins. As it is not feasible to reduce the diameter of the pins, the space required for fastening the pins to thebase cannot be reduced, nor can smaller socket contacts be used as the conventional socket contact is larger than the base pin.

One object of my invention is to provide a base and socket which can be made smaller than the conventional base and socket and yet have as many or even more contacts of ample area and properly spaced so that the electrical and mechanical properties of the smaller base and socket will meet all requirements.

Another object of my invention is to provide a base so constructed that the attachment of the leading-in wires to the contacts is simpler and easier than soldering to tubular contact pins.

A further object of my invention is to provide a base and socket having mechanically strong contacts which are so arranged that more angular space is made available for the contacts than in the conventional base and socket'and which are madev to occupy less angular space on the base and socket than the contact pins and socket contacts commonly used, yet have as great or even greater contact area than the conventional pin and socket contacts.

Still another object of my invention is to provide "improved base and socket contacts which are simple and inexpensive to make.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims, but the invention itself together with further objects "and advantages thereof, will best be understood by reference to the following description taken in connection with the accompanying drawings in which 10 Figure 1 shows a vacuum tube having a base constructed in accordance with my invention.

Figure 2' is an enlarged'top view of the base shown in Figure 1 with the bulb removed.

Figure 3 is a longitudinal section of the lower 110 llU ' tion with the tube shown in Figure I inserted in the socket.

Figure 8 is a top View of the socket shown in Figure 7 with parts in section-to show detailsof construction.

Figure 9 is a longitudinal cross-section of the empty socket of Figure 7 taken along the line 9-9 of Figure 8. Figure 10 is a perspective view of the top member of the socket of Figure 9.

Figure 11 is a longitudinal cross-section of the socket shown in Figure 7 with a tube base partly inserted, and

Figure 12 is a perspective view of-a contact and locking block made in accordance with my invention.

The vacuum tube annular shown in Figure l of the drawings has an evacuated bulb 15 which encloses the usual cathode and other electrodes, and has cemented to it a cup-shaped base 16, pref erably oimolded insulation. The base shown in Figures 1 to 4 has radial bosses 17 spaced around 35' lengthwise of the base.

its periphery near the bottom and extending These bosses have inclined shoulders 18 at the top and tongues 19 at the bottom to position and support the base contacts. As best shown in'Figure 4'the base has radial grooves 20 which register with'the underside of the bosses l7 and terminate in longitudinal slots 21= opening into the aperture 22 in the bottom of the base,

U-shaped contacts 23 consisting of fiat strips or ribbons, as shown'in Figures 5 and 6, are wrapped around and carried by the bosses 17; The ends oi the contacts are brought together and welded to fasten the contacts in place on the bosses and to form connecting lugs 24 which facilitate and simplify the; connecting of the lead wires 25 to the base contacts 23. When the tube is based these connecting lugs practically adjoin the lead wires 25 which project through the aperture 22 in the-base shell. The lead wires 25 may be inserted in the connecting lugs and then welded to a the lugs, thus making a good electrical connection moreeasily than by soldering and eliminating threading of the lead wires into the contact pins. Since the width of a boss with a contact mounted on it may be less than the diameter of the conventional tubular contact, and since the contacts are spaced around the exterior of the base instead of in a circle'on the bottom of the base near the rim as is-done with tubular contacts, more such contacts can be accommodated on a base of the usual size,,or the size of the base can be materially reduced and still the maximumnumber or" contacts now feasible for the usual size base can be'used. These flat contacts are strong and provide ample contact area.

The contact members 23 may to advantage be made'of nickel which can very easily be'worked and welded. They may be made in various ways, but I prefer to cut them from metal ribbon and formthem as shown in Figure 6, as'it is easier to shape the metal ribbon into such aflat contact than it is to make the usual type of tubular contact. By mounting the contacts on bosses projecting radially from the side of the base the overall length of the based tube is made materially less than that of a similar tube having tubular contacts in the bottom of the base.

It is obvious that the base canbe registered withv the socket in various ways; for example, by a stud or projection onthe base shell to enter a corresponding slot in the socket, by one boss of different size than the other bosses, or preferably by spa cing two of the bosses further apart than the others, as indicated at a in Figure 2.

A socket constructed in accordance with my invention and adapted for use with the tube base above described is shown in Figures 7 to 11 inclusive. It has ametalli-c cup-shapedmember 26 with a central stub 27 in the bottom and a flange like lip 28:. The metal cup 26 is an electrical shield for the'tube base and thus assists in preventing interstage coupling which is highly desirable in modern apparatus using highly "sensitive tubes.

Supported on the flange like lip 23 is an annular'or ring-shaped member 29' riveted to the lip. The annular member 29 overhangs the interior of thecup-shaped member 26 and, has radial undercut'slots or. grooves'30, best shown .in Figure 10. These slots 30, which are enlarged at 31 adja-' cent the opening in the annular member 29, also have transverse depressions or grooves 32 by means of which the socket contacts. 33 are positioned in the slots.

Each socket contactispositioned in one of theundercut slots 30, and hason-its outer end a lug 34and on its inner end a downwardly extending tongue 35 positioned in the enlarged end 31 of the slot The socket. contact is: formed with a hump .36 to fit into a .groove 32. An insulating block 37, with a projection 33forregistering with the groove 32, is clamped between the socket contact 33 and theflange-likelip 28 to lock the socket contact in place No rivets, or bolts or the like are needed to fasten the contacts to the socket. The contact spring need not be punched for a rivet or. bolt, hence the spring contact is stronger and it. may be made more compact than has heretofore been feasible. 7

As bestshown in Figure 8 longitudinal slots 39 on-the insideof the annular member 29' permit a tube base such as shown in Figure 1 'to be in serted in the socket. A. protector disc 40 normally held against the bottom of the annular member 29 by a biasing spring 41 centered on the stub 27. prevents the entrance of foreign objects into the empty socket, .and also prevents accidental touching of the socket contacts. The socket'may .be attached to a sub panel 42 by-means of nuts and bolts 43, as shown in Figure 7.-

Whenthe base is inserted. in the, socket; the bosses are registered with the slots 39, and the tube is pushed down into the socket against the disc 40 until the tops of the bosses clear two down-,

wardly projecting lugsv b and 0 provided on the annular member to insure that the bosses will not accidentally engage and twist the tongues 35 of the contacts while the base is being rotated into place. Another downwardly extending lug .d, which is longer than lugs bF'and c, prevents rotation of the base in a counter clockwise direo-' 1 tion,-as viewed in Figure v8, but permits rotation of the base in a clockwise direction to'bring the contacts "33 on the socketand the contacts 23 on the base into alignmentJ When this position has been reached, pressure is released'from the' tube and thebias'ings'pring-41 forcesthe' base 16'up against the tongues 35 of the contacts 33 as clearly shown in Figure 7 to provide electrical contact between the base and socket, the tongue 35 giving an inward wiping action as the biasing spring pushes the base into place. This locks the tube base in the socket and prevents poor operation of the tube due to loose contacts brought about by shock and jar, thus making this construction highly satisfactory for mobile and portable use.

It will thus be seen that I have provided a base and socket in which the maximum number of contacts which is now feasible to use on the conventional base and socket can be materially increased and still have the base and socket fully meet the electrical and mechanical requirements of such tube bases and sockets. In accordance with my invention I can materially reduce the size of the usual base and socket and still properly accommodate as many contacts as can now be used on the base and socket of usual size. The threading of lead wires in the tubular contact pins has been eliminated thus expediting manufacture and the electrical connection between the contact and leading-in wires has been materially improved. In addition to providing an improved method of attaching the contacts to the socket, the socket electrically shields the tube base and securely retains the tube base in place against the usual vibration and shock encountered in portable and mobile use. The shielding and wide spacing of the contacts which reduces interlead capacity also makes a base and socket embodying my invention most suitable for short wave use.

While I have indicated the preferred embodiments of my invention of which I am now aware and have also indicated only one specific application for which my invention may be employed, it will be apparent that my invention is by no means limited to the exact forms illustrated or the use indicated, but that many variations may be made in the particular structure used and the purpose for which it is employed without departing from the scope of my invention as set forth in the appended claims.

What is claimed as new is,

l. A vacuum tube base including an annular member having spaced radial bosses on the exterior thereof, said bosses having surfaces substantially perpendicular to the periphery of said annular member, and ribbon contacts wrapped around said bosses to lie flat against said perpendicular surfaces for providing contacts on the outside of said base.

2. A vacuum tube base including an annular member having spaced radial bosses on the exterior surface near one end, said bosses having surfaces substantially perpendicular to the periphery of said annular member, and ribbon contacts wrapped around said bosses to lie fiat against the perpendicular surfaces of said bosses for providing contacts on the exterior of said base, and lugs on said contacts adjacent the bottom of said base for leading-in wires.

3. A Vacuum tube base including a cup-shaped member having spaced longitudinal bosses on the periphery and near the bottom and having radial grooves on the outside bottom registering with said bosses for positioning leading-in wires extending through the bottom of the cup-shaped member, said bosses having surfaces substantially perpendicular to the periphery of said cupshaped member, and ribbon contacts wrapped around said bosses to lie fiat against said perpendicular surfaces and lugs on said contacts at the bottom of said base for the leading-in wires.

4. A vacuum tube base including a cup-shaped member having an aperture in the bottom thereof, spaced lon itudinal bosses on the periphery and near the bottom of said cup, said bosses hav-. ing surfaces substantially perpendicular to the periphery of said cup-shaped member, ribbon contacts wrapped around said bosses to lie fiat against said perpendicular faces, the bottom of said cup-shaped member having radial slots registering with said bosses and extending from said aperture to the rim of said cup, and lugs on said contacts registering with said slots for receiving leading-in wires extending through said aperture and positioned within the slots in said base.

5. A vacuum tube base including an annular member having a plurality of spaced longitudinal bosses on its periphery, said bosses having surfaces substantially perpendicular to the periphery

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