US2441938A - Shielded socket for radio tubes - Google Patents

Description

y 8, 19 8 R. B. MCGEE 2,441,938

SHIELDED SOCKET FOR RADIO TUBES Filed March 26, 1947 J LZQ, 2.

Patented May 18, 1948 UNITED STAT-ES PATENT OFFICE SHIELDED SOCKET FOR RADIO TUBES Robert B. McGee, Imperial Beach, Calif.

Application March 26, 1947, Serial No. 737,242

This invention relates to sockets for radio vacuum tubes, and more particularly, has reference to a socket of this type in which a built-in shield structure is embodied, constituting means for eifectively isolating the input and output circuits passing through the socket.

By way of background, conventionally formed vacuum tube sockets have not hitherto been formed with shields, for the purpose stated above. In fact, until fairly recent developments have pointed to the need for such a shield, there has been no necessity for constructing sockets with circuit-isolating means as indicated.

With the advent of present-day high amplification circuits, and with the resultant steadily increasing use of high amplification tubes, there is arising the problem of feedback of energy between the input and output circuits of the tubes, occurring in the tube sockets, pointing to the necessity of completely shielding the circuits one from the other in the sockets so as to eliminate this reaction.

Some steps have already been taken in this direction, but no provision has been made for complete elimination of feedback between the input and output circuits within the tube socket. It is accordingly the primary object of the invention to provide a tube socket in which is embodied means for efliciently and completely isolating the input and output circuits. by closing all paths of feedback between these circuits. Additionally, the structure designed for this purpose provides isolation of the circuits from external fields of reaction extending around the filaments and other element leads.

In order to carr out the stated objects of the invention, I provide a tube socket in which is incorporated a built-in cross sectional shield structure, and in which, additionally, are provided a cylindrical shield structure providing further isolation from the fields extending around the filaments, and a sleeve shield structure adapted to shield the grid and plate pins of the tube, and the leads extending therefrom out of the socket.

With the foregoing and other objects in view which will appear as the description proceeds, the invention consists of certain novel details of construction and combinations of parts, hereinafter more fully described and pointed out in the claims, it being understood that changes may be made in the construction and arrangement of parts without departing from the spirit of the invention as claimed.

Referring to the drawings:

Figure 1 is a perspective view, showing a tube,

2 Claims. (Cl. 174-35) a portion of a chassis shield plate, and a tube socket constructed in accordance with the invention, these parts being shown detached one from the other.

Figure 2 is a longitudinal vertical sectional view through a tube socket constructed in accordance with the invention, the socket being mounted on a chassis shield plate.

Figure 3 is a view taken substantially on line 3-3 of Figure 2.

Referring to the drawing in detail, the letter of reference T designates generally a vacuum tube of conventional construction, constituting no part of the invention, said tube being provided with a centrally disposed locating prong 5 and contact or base pins 6, which in the tube illustrated, are disposed in a circle around the locating prong. It is pointed out, in this connection, that the tube socket which is the subject of the application does not require the use of tubes of the particular type illustrated in Figure l, the tube socket being adapted for the of various types of tubes, as desired, as will be apparent from the description.

The letter of reference C designates a chassis shield plate, having the opening '5, through which contact is established between the tube T and the tub-e socket.

I provide in my improved tube socket an outer shield 8. This is formed in two opposed and identically constructed sections. Each section is pro vided with an outer wall 9. The side edges of each outer wall 9 are bent outwardly to provide opposed side flanges iii. Between its side flanges Ill, each of the outer walls 9 is bent rearwardly, so that when the two sections forming the outer shield 8 are placed together, the over-all structure of the tube socket, when viewed in horizontal section, as shown in Figure 3, is substantially elliptical.

The respective sections forming the outer shield 8 are additionally formed with flat-surfaced opposed inner walls ll, that extend from top to bottom of the tube socket. The upper edges of the opposed inner walls are formed, intermediate their ends, with substantially semicircular recessed portions I2, between which are received the locating prong 5.

As shown clearly by Figures 2 and 3, the inner walls I! are slightly spaced from each other, by means of insulating washers I3. These are interposed between the side flanges H1, and receive screws l4, that fixedly secure together the two sections comprising the outer shield 8.

Each of the sections comprising the outer shield 8 is additionally provided with a bottom aeenoee cover I5. The bottom covers I 5 are formed with opposed depending flanges 55 that are spaced from each other by washers ll, there being provided screws I 8 whereby the respective bottom covers l5 may be connected together.

Each of the bottom covers 55 may additionally be securely locked in position by means of latching or looking elements 18 whereby the covers may be secured to the outer walls 9.

Each of the sections forming the outer shield 8 is formed with a top piece !9 that is preferably of integral formation with the outer Wall 9, the top piece having an opening in which is received a fastening means 2b, by means of which the tube socket may be secured detachably to the chassis shield plate C. The inner edges of the respective top pieces 59 are extended upwardly to form opposed semi-circular collars or flanges 25. These are extended upwardly through the open ing 7 of the chassis shield plate 0, and are insulated therefrom by means of an annular insulating washer 22 that is interposed between the collars 2i and the wall of the opening I.

The opposed collars 25, after the two sections forming the outer shield 3 are secured together, form a large circular opening that is split diametrically into halves by the spaced apart upper edges of the inner walls El. In each of the semicircular halves of this opening there is mounted, by any suitable means, a socket element 23, which is formed of insulating material, and which is provided with suitable openings 24 for receiving the contact pins 8 of the tube T. The socket elements are each formed with curved edge that abuts against the collar 2!, and with a straight edge that abuts against the inner wall ll, the straight edge being rearwardly curved alon part of its length to receive the recessed portion l2 of each inner wall I l Thus it is seen that the input and output circuits of the tube and tube socket are eiiiciently separated and isolated completely, by reason of the provision of a socket formed in the manner described above. in this way, there is no danger of the possibility of a feedback of energy occurring between these two circuits, inasmuch as the paths thereof are completely closed ofi by the construction described.

However, there is also the possibility, in tubes of the type described, of the circuits being interferred with by reacting to external interfering fields.

In order to prevent this, I provide a shield structure Within each of the sections comprising the outer shield 8, this being in the nature of an inner shield. While the outer shield 8 is con-- structed in separate sections for the purpose of isolating the input circuit from the output circuit, the inner shield which is placed within each section is for the specific purpose of isolating each of the said circuits from reacting to the presence of external interfering fields at the socket itself. This is quite common to circuits where high mutual conductance tubes are used.

My inner shield comprises a curved member 25, which is transversely curved in semi-circular form, and which has its side edges secured to the inner walls I l of each section. The curved members 25, as clearly seen from Figure 2, constitute an extension of the collars 2| and result in the formation of a cylindrical enclosure extending from the top to the bottom of the socket, said cylindrical enclosure being divided as hereinbefore. described.

I further provide in. my device shielding pipes or sleeves 26, which are extended laterally through the outer walls 9 and curved members 25, being then extended upwardly to pass through the socket elements 23, and terminating at the upper surface thereof. The shielding pipes 26, as clearly shown in Figures 2 and 3, fully surround the openings 2:; of the socket 23 from the upper to the lower surfaces thereof, providing interier once-resistant shields for the contact pins 6, and additionally providing an interference-resistant shield for each of the elements leading from the contact pins 5.

By reason of the construction which I have described, I have provided a tube socket with built-in shield, that is fully effective in high amplification circuits particularly, in isolating the respective input and output circuits from one another, so as to prevent completely any energy leakage between these circuits within the socket. Further, I have provided means whereby each of the respective circuits, in passing through the tube socket, is isolated from reaction from, or interference by, other elements. In addition, the use of the shielding pipes 25 further eliminates any pickup of stray energy from other paths of introduction, such as the other elements on the particular side of the socket in which said pipes are respectively mounted. Thus, the pipes close off effectively the last paths of stray pickup both from the other elements themselves, and from the leads extending to said elements.

It is pointed out that the use of separated inner walls H, on each of the sections comprising the outer shield 8, eliminates re-radiation occurring at high frequencies.

Completing the construction of a tube socket in accordance with the invention, there are secured to the side flanges Ill soldering lugs 21 whereby the shield may be wired to ground connections,

What is claimed is:

l. A radio tube socket, including an outer shield, the outer shield comprising separate sections insulated from each other, a socket element, carried by each section, formed with openings for receiving the contact pins of a radio tube, and shielding pipes extending through the socket elements around the openings therein, said shielding pipes being extended through the walls of the outer shield.

2. A radio tube socket, including an outer shield, the outer shield comprising separate sections insulated from each other, an inner shield member dividing each section into separate chambers, a socket element carried by each section, said socket elements being formed with openings for receiving the contact pins of a radio tube, and shielding pipes extending through the socket elements and around the openings formed therein, said pipes being extended downwardly from said openings and through the walls of the outer shield.

ROBERT B. MCGEE.

REFERENCES CITED The following references are of record in the hire of tiis patent:

UNITED STATES PATENTS Number Name Date 1,973,248 Evans Sept. 11, 1934 FOREIGN PATENTS Number Country Date 262,226 Great Britain Dec. 9, 1926

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