US2111381A - Radio receiver apparatus - Google Patents

Description

March 15, 1938. L. E. BARTON I 2,111,381

RADIO RECE IVER APPARATUS Fil ed April 25, 1936 A Tram/m1.

Patented Mar. 15, 1938 UNITED STATES PATENT @FFECE RADIO RECEEVER APPARATUS Delaware Application April 25,

4 Claims.

My invention relates to radio receiver units such as high frequency amplifiers and particularly to intermediate frequency amplifiers employed in superheterodyne receivers.

An object of my invention is to provide an improved unitary assembly for an amplifier stage or the like.

A further object of my invention is to provide an improved intermediate frequency amplifier unit which may be lined up and tested before being mounted on the receiver chassis.

A further object or" my invention is to provide an improved shielded amplifier stage.

A still further object of my invention is to provide an improved amplifier stage assembly in which the amplifier tube prongs are shielded.

In one preferred embodiment of my invention an intermediate frequency transformer of an amplifier stage is mounted on the under side of a vacuum tube socket. The vacuum tube of this amplifier stage, when inserted in this socket, provided with a suitable shield unless it is a metal tube which does not require shielding. The transformer is provided with a suitable shield. supported from the socket whereby the tube prongs are shielded.

The invention will be more clearly understood from the following description taken in connection with the accompanying drawing in which,

Figure l is a front view, with a portion broken away, of one embodiment of my invention;

Fig. 2 is a side view, partly in section, of the unit shown in Fig. 1; and

Fig. 3 is a circuit diagram showing the electrical connections of the unit shown in Figs. 1 and 2.

Referring to Figs. 1 and 2, my invention is shown applied to an intermediate frequency an plifier unit of a television receiver. The amplifier unit comprises a vacuum tube socket which may be of conventional construction. The tube socket, as shown in Fig. 2, consists of a disc I of insulating material, such as Micarta, having openings therein for the prongs of a tube indicated at 2 and having contact members 3 located underneath these openings for engagement with said prongs.

On the upper side of the socket disc I there are located, in the order named, a washer of insulating material, a threaded shielding cap 6, a mounting plate I, and a shield support 8. The elements I, 4, 6, l and 8 are riveted together at two diametrically opposed points, only one of the rivets being shown in the drawing at 9. These rivets also fasten two coil brackets H to the 1936, Serial No. 76,338

under side of the socket. Obviously, the coil supporting brackets ll may be supported from the shielding cap S instead of from the socket itself. An angle member i2 is riveted to the upper side of the plate '5 to function as a supprising a primary coil 5% and a secondary coil ii, is supported by means of a tube 58 of insu-- lating material suspended from the supporting brackets ii. The transformer coils iii and ii are tuned by condensers l9 and respectively, shown more clearly in Fig. 3. Like parts in Figs. 1, 2 and 3 are indicated by the same reference numerals.

The condensers i9 and 2! are mounted on a disc of insulating material, this disc being supported from the transformer tube it.

In the particular amplifier unit illustrated, trap circuit comprising an inductance coil 2 and a condenser is tuned to the frequency or the intermediate frequency sound carrier accompanying the picture signal.

A transformer shield 26 of aluminum or the like is held in screw-threaded relation with the metal shielding cap d whereby the tuned intermediate frequency transformer, the socket contact members 3 and the tube prongs are well shielded.

As is evident from an inspection of Fig. 3, where the amplifier unit shown in Figs. 1 and 2 is enclosed by the dotted rectangles 2i and 28, each amplifier unit includes two resistor-condenser filter sections in each of the grid and plate circuits. It will be noted that each amplifier unit includes six filter resistors 29 and six filter condensers 3!. These resistors and condensers are mounted on the front side and back side, respectively, of a panel of insulating ma terial riveted to the mounting plate i. Also, a filament by-pass condenser 33 is provided.

Because of the length of the leads, a condenser is mounted adjacent to the socket contact members and connected between the screen grid and cathode contact members 3. It may be noted that in the circuit shown in Fig. 3 the screen grid and suppressor grid of the tube 2 are connected together to increase the mutual conductance of the vacuum tube and thereby improve the gain. A resistor 34 is shunted across the primary l6 for the purpose of broadening the tuning of the transformer.

In Fig. 3 one complete amplifier stage and portions of two other amplifier stages are illustrated. Referring to the complete stage, all of the amplifier elements enclosed by the upper dotted rectangle 28 are shielded by the tube and transformer shields I3 and 26, respectively. The resistors and condensers enclosed by the lower dotted rectangle 21 are mounted on the panel 32.

Attention is called to the fact that the grid lead 36 is the only signal lead above ground potential connecting successive amplifier stages. This lead is brought through an opening in the shielding cap 6 (Fig. 2) for connection to the grid cap M of the succeeding amplifier tube by means of a clip 31.

It should be understood that the connecting lead between amplifier stages may be the plate lead, if desired. In that case each amplifier unit comprises a vacuum tube and the preceding intermediate frequency transformer, instead of a vacuum tube and the succeeding transformer, as illustrated.

My improved unitary vacuum tube and shielded coil assembly is useful for superheterodyne oscillators as well as for amplifiers. When the invention is applied to oscillators, the coils which correspond to the transformer coils illustrated in the drawing are the coupled plate and grid coils of the oscillator.

From the foregoing description it will be apparent that various modifications may be made in my invention without departing from the spirit and scope thereof, and I desire, therefore, that only such limitations shall be placed thereon as are necessitated by the prior art and are set forth in the appended claims.

I claim as my invention:

1. An intermediate frequency amplifier unit comprising a tube socket consisting of a plate of insulating material having openings therein for the prongs of a vacuum tube and having prong contact members underneath said openings, an intermediate frequency transformer supported underneath the said socket and supported to form an integral unit therewith, and tuning condensers for said transformer which are mounted underneath said transformer and inside said shield.

2. A unitary structure comprising a vacuum tube socket having a shield supporting member fastened thereto from which a coil shield may be supported and having a second shield supporting member fastened thereto from which a tube shield may be supported, said socket and shield supports comprising a unitary assembly, a plurality of coupled coils supported from and underneath said assembly, a coil shield surrounding said coils and supported from one of said shield supporting members, and a tube shield supported by the other of said shield supporting members.

3. A unitary structure comprising a vacuum tube socket consisting of a plate of insulating material having openings therein and having tube prong contact members located underneath said openings, a shielding cap, a mounting plate and a shield support mounted on top of said tube socket plate in the order named and fastened thereto to form a unitary assembly. a plurality of coupled coils supported from and underneath said assembly, a tube shield secured to said shield support and a coil shield secured to said shielding cap whereby said tube shield is above said socket and said coil shield is below said socket.

4. An amplifier unit comprising a vacuum tube socket consisting of a plate of insulating material having openings therein and having tube prong contact members located underneath said openings, a shielding cap positioned over said socket and having an opening in the top thereof to permit insertion of the prongs of a tube, said shielding cap having down-turned edges, said socket and said shielding cap being fastened together to comprise a unitary structure, a high frequency transformer supported from said unitary structure, and a shield surrounding said transformer and engaging said shielding cap edges.

LOY E. BARTON.

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