US2498907A

US2498907A - Radio frequency shielded switch

Info

Publication number: US2498907A
Application number: US508353A
Authority: US
Inventors: John B Atwood; Ferdinand J W Schoenborn
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1943-10-30
Filing date: 1943-10-30
Publication date: 1950-02-28
Anticipated expiration: 1967-02-28

Description

Feb. 28, 1950 J. B ATWOOD ET AL 2,498,907

RADIO FREQUENCY SHIELDED SWITCH Filed Oct. 50, 1945 2 Sheets-Sheet 1 INVENTOR JOHN B. ATM/000, FLQZ /VA/VD J M ,SGHOE/VBOB/V ATTO RN EY Feb. 28, 1950 J. B. ATWOOD ET AL RADIO FREQUENCY SHIELDED SWITCH Filed Oct. 50, 1943 uIuALIII IIIIIIIIIIIIIIII' 2 Sheets-Sheet 2 5'7 J8 69 Q 0 r INVENTOR 29 JO///V B. ATWOOD,

FERDINAND J W SCHOE/VBOE/V BY #Z/wm/ ATTORNEY Patented Feb. 28, 1950 UNITED STATES PATENT OFFICE RADIO FREQUENCY SHIELDED SWITCH John B. Atwood andFerdinand J. W. Schocnborn,

Riverhead, N. Y., assignors to RadioCorporation of America, a corporation of Delaware Application October 30, 1943, Serial N 0. 508,353

'2Claims. 1

This invention relates to a new and useful radio frequency shielded switch which is particularly adapted as an antenna switch to remotely transfer connections from the. antenna circuit to either the receiver or transmitter, althoughnot specifically limited thereto,

An object of this invention is to provide a novel switch which is compact and. simple in construction.

Another object of this invention is to provide a single pole double throw switch with very high attenuation from the operating to the non-operating side with quiet circuitoperation.

Still another object of this invention is to provide a switch with easily replaceable terminal fittings.

A feature of this invention is the novel arrangement of a radio frequency closed shielded chamher in which a coaxial line terminates at the central portion. At each end of the chamber there is also terminated a coaxial line which is connected to a receiver and a transmitter circuit. .A switching member is located .within the chamber for alternately connecting one of the end coaxial lines with the coaxial line located at the central portion.

Briefly, the arrangement of the switch of this invention is that of three coaxial line fittings'terminated in a shielded-chamber in which two bars are moved back and forth by low loss plastic rods operated by solenoids. The antenna is connected to the central coaxial line fitting, the transmitter to one of the others, and the'receiver'to the third. The switch of this invention has been used for switching an ultrahigh frequency radio transmitter operating at 1500 megacycles and was found to have very high attenuation from the operating to the non-operating side, the measured value being approximately 100 decibels.

This inventionwill bestbe understood by referring to the accompanying drawings in which:

Fig. 1 is atop view of the antenna switch with its coverremoved,

Fig. 2 is a sectional view, the section being taken on line .22 of Fig. 1,

Fig. 3 is an end elevation of Fig. 1,

Fig. 4'is a circuit diagram of the operating solenoids,

Fig. 5 is a detailed section of a coaxial line con- .necting fitting, and

Fig. 6 is an end elevation of Fig. 5.

Referring now in detail to the accompanying drawings, a metallic plate I forms the base portion of the switch. A metallic bracket 2 is secured to base I by means of screws 3. The upper terminal fittings'2l,-'2 2 and 23.

stud 34 and nut 35.

portionof bracket 2 is slotted with two slots 4 and 5. The central portion of bracket 2 is bent at right 'angles at 6. Thetwo extreme ends of bracket'2 are also bent at 1 and 8 in an opposite direction to that of the bent portion 6. A metallic dust 'cover'9 surrounds the entire switch and is fastened'to bracket2'by means of screws Ill and I l which are'threaded'into the bent portions 6, l and 8, thus securing the cover to the bracket 2. At-the side of bracket 2 there is secured a housing 12 which serves as a radio frequency shielded chamber and iscomposed of side walls [3,14 and end members 15, which are soldered together. A top cover It is secured in place by machine screws H, the interior of the chamber being silver plated for good electrical conductivity. The sidemember has apertures l8, l9

and 20"through which pass three coaxial line terminal fittings 21,22 and 23. These fittings have a square shouldered portion and are secured to'chamber wall 14 byumeans of screws 11A passing'through the'shoulder portion. The terminal fittingsextend beyond the base I and are threaded at2'4 for coupling to a coaxial line outer conductor (not shown). The other side member l3 has located therein two apertures25 and 26 which are located intermediate to the apertures for Two push rods 21 and 28 of low loss plastic material-pass through the apertures '25 and 26. The push rods 21 and 28 aremoved by means-of solenoids 29 and 30 which are located on the-opposite side of support bracket Z'from that of housing l2. The armatures 3| and 32 of solenoids -2-9-and 30 are connected to a'pivoted arm 33 which is supported from the upper portion of-member-2 by means of a pivoted Two fiat spring members 36 and 3'! connect the endsof arm 33 with push rods 21 nd-28 and are coupled bymeans of slotted portions 38 and 39. The portions of push rods 21 and 28 which extend within the housing [2 'are securely fastened to two-metallic bars 40 and 4|, each one of which has located at its extreme end contact tips and 43, 44 and 45, which are composed of a gold'and silver ailoyhaving a very high corrosive resistance and a low contactresistance. To provide better shielding from the operating to-the non-operating side, the bars 40 and 4| are recessed in the wall [3 when in the groundedposition.

The centralcoaxial terminal member 22 has supported thereon a relatively large contact tip 46 which is made wide enough to receive both ends of the bars 40 and M. The inner conductor portion of the terminal members 2| and 23 are each provided with contact tips 41 and 48 which are positioned so as to make connection with the extreme outer ends of metallic bars 40 and 4|. An insulating terminal board 56 is secured to solenoid 29 and has located thereon terminals 51,

58 and 59 which connect to the solenoid windings.

The circuit switching arrangement, as shown in Fig. 4, comprises terminal board 56. A terminal 58 is connected to one end of each of the solenoids 29 and 30 and serves as a common terminal. The other end of solenoid 29 connects to terminal 51, and the other end of solenoid 30 connects to terminal 59.

Figs. 5 and 6 show the construction of the coaxial terminal member 2| to which is fastened an insulating disc 50 located at the extreme end of the tube 2|, the insulating disc 50 being held in place by means of having the end of the tube 2| spun over at 5|. In the central portion of tube 2| there is located a second insulating washer 52 which is retained in place upon the central conductor 53 by means of a shoulder portion 54. The insulating washer 52 is held within tube 2| by means of a split ring 55 which is snapped into a. slot 55A. While only one terminal member 2| is described above, terminal members 22 and 23 are of similar construction. The inner conductor socket connecting member 49A is located within the terminal member 2| and is concentrically spaced by insulating washers 50 and 52. The ends of socket connecting member 49A are slotted with three slots 493 which provide a good gripping electrical contact to a rod or wire of the inner conductor of a concentric line (not shown). The washer 52 has a pin 52A to hold the connecting member 49A in place within the terminal member. The above mentioned terminal construction is such that the members 2|, 22 and 23 may be easily replaced.

In the operation of this switch the antenna is connected to the center coaxial terminal fitting 22, the transmitter is connected to terminal fitting 2|, and the receiver to terminal fitting 23. The switch is operated remotely from a manually operated switch, not shown, which closes an-elec- 4 trical circuit preferably supplied from a direct current source to energize the windings of solenoids 29 and 30. For example, when solenoid 29 is energized, armature 3| will be drawn down and will carry with it the end of pivoted arm 33 which, by means of spring 36, will force the push rod 21 down and will at the same time make an electrical connection between contacts 46 and 41. At the same time the arm 4| is forced up:- ward to rest upon the inside portion of cover l5 to make a ground connection between contacts 6| and 62. When the manually operated remote controlswitch is thrown in the opposite direction, the position of bars 40 and 4| is changed by means of having solenoid 30 energized. In this position the bar 4| makes connection between contacts 46 and 48, and the bar 40 makes a ground connection between contacts 60 and BI, thus providing quiet circuit operation with, freedom of the ordinary circuit noise.

While this invention describes a mechanism for carrying certain switching operations into efiect, it will be apparent to one skilled in the art that the invention is by no means limited to the particular devices shown and described, but' that many modifications may be made without departing from the scope of the invention.

What we claim is:

1. An ultra high frequency switch comprising a metallic casing, three coaxial line terminal members each having an inner conductor extending within said casing, a closed metallic shielded chamber within said metallic casing, said closed metallic shielded chamber having a recessed wall portion, each one of the inner conductors or said coaxial line terminal members 1 terminating in said shielded chamber and having a terminal contact located thereon and electrically connected thereto, said contacts being insulatingly supported in the central portion oi said coaxial line terminal members and connected to the inner conductor thereof, two movable contact bars arranged within said closed metallic shielded chamber to permit one of said bars to connect the center one of said terminal contacts to the outer one of said terminal contacts, and means to electrically connect the unconnected movable bar to the recessed Wall portion of said shielded chamber.

2. An ultra high frequency single-pole doublethrow antenna switch comprising a metallic casing, a base member closing an end of said casing, a bracket member secured to said base member, said bracket having two slotted portions located therein, a closed metallic radio frequency shielded chamber located on one side of said bracket, a pair of solenoids located at the other side of said bracket, three coaxial line terminal contact members passin through said base member and extending into one of the walls of said radio frequency shielded chamber, a pair of push rods passing through another wall of said radio frequency shielded chamber, a pivoted arm coupled to each armature of said solenoid, two flat spring members connecting the insulating rods with said pivoted arm, and extending through the slots in said bracket, whereby the two movable contact bars are arranged to alternately connect the center one of said terminal contact members with the outer one of said terminal contact members when one of said solenoids is energized.

JOHN B. ATWOOD. I FERDINAND J. W. SCHOENBORN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS