US2550921A - Sliding coaxial switch - Google Patents

Description

y 9 1 s. G. GREENE 2,550,921

SLIDING cQAxIAL swrrcn Filed Aug. 11, 1948 a; E a? 201 Patented May 1, 1951 SLIDING COAXIAL SWITCH Gardiner G. Greene, Newton, Mass., assignor to The Workshop Associates, Incorporated, Newton Highlands, Mass., a corporation of Massachusetts Application August 11, 1948, Serial No. 43,603

8 Claims.

In high frequency communication systems it is often desirable consecutively to establish connection, through a wave guide channel, between selected components of several groups of circuit elements. Such elements are for example those of the antenna, on the one hand and receiver or transmitter of television and frequency modulation systems on the other hand. To eliminate reflected waves, it is a common practice to couple the antenna and receiver by means of a coaxial cable having a characteristic impedance which is substantially the same as that of the connected antenna. The matching of the characteristic impedance of the receiving elements introduces difiiculties when, for example for sales demonstration purposes, several receivers are to be successively connected to the same antenna, or conversely when, to improve signal strength, a receiver is selectively connected to one of a plurality of receiving antennas.

Objects of this invention are to provide a switch" number of lines, which is economical to construct, and which advances the art of switch manufacture generally.

In a broad aspect the invention contemplates a multi-position switch comprising a hollow con- 8' .5 ing a plurality O1" coaxial connectors each having a projectin contact extending within the body used to couple the switch to the respective coaxial lines. A connector is centrically located in one or each of the end plates, the remaining connectors being positioned in the wall of the body. A movable assembly is supported within the body and electrically connected to the projecting contact ol' the end plate connector. This assembly includes an operating means and a movable arm for selectively making contact with the respective projecting contacts of the wall connectors. The configurations of the body and movable assembly are dimensioned relatively to each other so that the characteristic impedance of the switch is of substantially the same magnitude as that of the connected lines.

In one specific aspect the switch according to the invention comprises a holfow body having a cylindrical wall, the ends of which are closed respectively by two end plates and a plurality of connectors for coupling the switch with the re- I spective coaxial lines.

, tive connectors located in the end plates.

ductive body having an opening which is closed .by a plate, a plurality of coaxial lines leading into the body having their outer tubular conductors conductively connected to the body and a coaxial linehaving its outer tubular conductor mounted on the plate, with the ends of the inner conductors extending into the body, an assembly movable within the body having a conductive connecting portion irictionally engaging the inner conductor which is mounted on the plate and a contact portion conductingly joined to the connecting portion and resiliently fitting the end of each one of the inner conductors which extend into the body, and an actuator for switch 7 ing the contact portion between adjacent inner of the above indicated type has a cylindrical wall with its ends closed by end plates and support- A connector is positioned in a tapered aperture centrically located in the inner surface of each of the respective end plates. The remaining connectors are positioned in the body wall in a plane passing through the axis thereof. A cylindrical member is supported coaxially within the body wall. Each end of the member is conically shaped with a hole in the apex thereof for engaging a contact pin projecting into the interior of the body from the respec- A slidable assembly is supported within the body upon the cylindrical member so that a recess in one end of a movable contact arm selectively makes with the respective contact pins projecting within the body from the wall connectors. The other end of the contact arm is fastened to an operatend of the cylindrical wall is closed by an end plate having a tapered aperture wherein is centrically located a connector. An insulating cover plate, having a recess wherein is supported one end of the cylindrical member, closes the opposite end of the wall. The other end of the member is conically shaped with a hole in the apex thereof for engaging the contact pin of the end plate A slidable assembly is supported within the body upon the cylindrical member so that a recess in one end of a movable contact arm selectively makes with the respective contact pins projecting from the wall connectors. The other end of the contact arm is fastened to an operating handle which projects out through a slot located in the body wall diametrically opposite the wall connectors. A spring loop is interposed between the ends of the contact to insure adequate electrical contact pressure. I

In all these embodiments the relative diametersor the wall and the cylindrical member and the relative tapers of the end plate and the end of the cylindrical member are proportioned so that the characteristic impedance of the switch is of substantially the same magnitude as that of the connected coaxial lines.

These and other objects and aspects of the invention will be apparent from the typical embodiment thereof illustrated in the accompanying drawing in which: v h

Fig. 1 is a side elevation view of one embodiment of the invention; I

Fig. 2 is an end elevation 'view of the same embodiment;

3 is a cross sectional view on line 3 -4 of Fig. 2; v

Fig. '4 is a cross sectional view on line 4-4 otFigl; Fig. 5 is an enlargedfragmentary cross sec-- tional view of the slidable assembly;

Fig. Bis a cross sectional view on the line 6'6 hf. Fig.5; and v Fig 7 is a fragmentary cross sectional view "or another embodiment of p the invention;

The body of the switch "shown in Fig. 1 cornprises a cylindrical Wall 12 each end of which is closed by a respective end plate M secured by ihe'screivs l5. Located in a tapered 'aperture centrically positioned in each'of the respective end plates I4 is a flangednipple i1 ofa conventional coaxial connector I8. A checknilt Ill ecures each of the connectors l8 in their i' ective aperture H5. The taper of the side walls f each of the apertures I'fi ispro p'o rtioned 'in a manner to be described in'detail'hereinafte'r.

A plur 'ality of similar connectors 2'! are secured in the wall 1'2 in a plane passing through the wall axis. These connectors "2! are secured by check nuts in a manner analogous to that hywhich the connectors I8 are secured in the end plates 14. Although four connectors 2| are shown infigs. 1 and 3,,it will beund'erstoo d that "o .e of the principal advantages of this type of switch jisjthat by suitably increasing the length hi the wall 12, any. desired "number of connectors 2'1 can besecured therein. 7 p

A plurality of contact pins 22, each of, which is electrically connected to the central conductor "of the respective connector 21, projects within the interior of the switch body. A similar contact pinffifi projects from each of the respective end plate connectors l8 to. support a cylindrical conducting member 26. The pins 23 can be formed as an integral extension of the tapered 'ends 24 of the cylindrical member 26;

A slidable assembly 23 (shown in detail in Figs fl, 5 and '6) is movably supported upon the cylindrical member 26 so that its contact arm 21 selectively makes with the respective pins 22 which project from the wall connectors 21. The

' a'rm g7: comprises two identical strip pieces 29 of berryllium bronze 'or other material having similar characteristics, maintained in juxta posed relationship by means of the rivets 3| and 32. The rivets 32 also pass through the end of the extension 33 of a nonconducting operating handle assembly 34. The portion of each piece 29 between the rivets 32 and 3| is formed in the shape of a semicircle so that surface to surface contact is made with the cylindrical member 26. As is best shown in Fig. 6, the ends of each piece 2-!) abutting the contact pin 22 are in the shape of a double ogee, the recess 36 formed thereby cooperating with the similar recess -of the juxtaposed piece to provide a detent. The portion of each piece 29 located between the og efe shaped end and the rivet 3| is of reduced width and is bent to form a spring loop 35-, thereby insuring both the proper locking action of the detent and providing adequate electrical contact pressure.

The handle extension 33 projects through a slot 31 cut in the cylindrical wall l2 diametrically opposite the wallconnectors 2i. Molded integrally with the extension 33 is a knob 38 curved generally to conform with theouter contour of the wall 12 and having a projection which can begrasp'ed by the fingers-of an operator to move the slidable assembly '28.

To match the characteristic impedance 20 of theconnecting lines the dimensions of the switch must be proportioned so that Zo /L/C where L and C are the distributed inductance and capacitance per unit length respectively;

As the dielectric 'constant of air is unity; the relation of the diameters of the cylindrical member 26'andthe wall 12 are given by the formula zi -138 logi' -D/d. where D is the inner diameter of the outer conductor; and cl is the outerdia-meter oftheinner conductor v The s irfacejtof each of the etaieces 1'4 is tapered'relatively to the taper, of the eerie lated conical e n"d 2" 4 of the"'cylindrical Yn'e'rnhr v. ."6 so that "any point "on one of the tapered surfaces liesfin the circumference of a t rircleii'i a plane normal to the axis "of the ebne f'orm'ed by such surfaceand having adiameter prepaition'ed with respect to the. diameter of ajcircle concentric and coplanar with-the first circle and passing throughthe pointfon the other tapered surface closest to the point on the -first*tapered *s nrface whereby the ratio of diameters when substituted-in the abovc fo'rmula results in the desired characteristic impedance.

It isals'o "within the scope of this invention to provide a switch with a connector IBf'in one end-only. With such an arrangement, theop- 'p osite end of the wall i2 is closed as is shown in Fig, 7 by an insulating cover 'plat'e. 13. In this embodiment the 'end of the cylindrical member 26 engages a recess 2 1 'inthe cover plate 13 so thattlie'inernber 25 is supported coaxially with 'respecttothe inner 'surfacejof the wall '12, The j'constructionbf the remainder of the switch is identical with that of the first "embodiment, the

location of the wall connectors :21 and the'd ebranch leads are selectively to be connected to the' end of a main lead, the and connector [8 of a switch such as shown in Fig. 6 is connected to the end of the main line.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includesall modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. A multiposition switch for selectively connecting a plurality of coaxial lines comprising a hollow body having an end plate and a cylindrical wall with an end closed by the plate, a

- plurality of coaxial connectors for couplin said switch to the respective lines, each of said connectorshaving a projecting contact extending within said body, one of said connectors being centrically located in the end plate, the remaining connectors being positioned in said wall in a plane through the wall axis, a supporting member mounted within said body by the projecting contact of the end plate connector, and a slidable assembly carried by said supporting member and including operating means and a movable contact arm for selectively making with the respective projecting contacts of the wall connectors, the dimension of the wall and the supporting member being proportioned relatively to each other so that the characteristic impedance of the switch is of substantially the same magnitude as that of the connected lines.

2. A multiposition switch for selectively con.- necting a plurality of coaxial lines comprising a hollow body having an end plate with a tapered aperture centrically located in the inner surface thereof and a cylindrical wall with an end closed by the plate, a plurality of coaxial connectors for coupling said switch to the respective lines, each of said connectors having a projecting contact extending within said body, one of said connectors being located in the tapered aperture of the end plate, the remaining connectors being positioned in said wall in a plane through the wall axis, a cylindrical member having a conically shaped end abutting the projecting contact of the end connector, and a slidable assembly supported within said body and including operating mean extending through the body wall, and a movable contact arm positioned circumjacent the cylindrical member for selectively making with the respective projecting contacts of the wall. connectors, the taper of said aperture and said cylindrical member being proportioned relatively to each other so that the characteristic impedance of the switch is of substantially the same magnitude as that of the connected lines.

3. A multiposition switch for selectively connecting a plurality of coaxial lines comprising a hollow body having an end plate and a cylindrical wall with an end closed by the plate, a plurality of coaxial connectors for coupling said switch to the respective lines, each of said connectors having a projecting contact extending within said body, one of said connectors being centrically located in the end plate, the remaining connectors being positioned in said wall in a plane through the wall axis, a cylindrical memb'er having a conically shaped end abuttin the projecting contact of the end connector, and a slidable assembly supported within said body and including operating means extending through the body wall and a movable contact arm for selectively making with the respective projecting con.- tacts of the wall connectors, the end of each projecting contact of the respective wall connectors being spaced from-the cylindrical member so that the characteristic impedance of the switch is of substantially the same magnitude as that of the connected lines.

4. A multiposition switch for selectively connecting a plurality of coaxial lines comprising a hollow body having two end plates, and a cylind ical wall with a longitudinal slot therein, the ends of said wall being closed by the respective plates; a plurality of coaxial connectors for coupling said switch to the respective lines, each of said connectors having a projecting contact pin extending within said body, one of said connectors being centrically located in each of the respective end plates, the remaining connectors being positioned in said wall in a plane passing through both the wall slot and the wall axis; a cylindrical member having conically shaped ends, each with a hole in the apex thereof for engaging the contact pin of the respective end plate connectors; and a slidable assembly supported within said body including an operating handle with'one" end extending through the wall slot, and a movable contact arm fastened to the opposite handle end and slidably engaging said cylindrical member for selectively makin with the respective projecting contacts of the wall connectors.

5.--A multiposition switch for selectively connecting a plurality of coaxial lines comprising a hollow body having an end plate, a cover plate of insulating material having a recess therein and a cylindrical wall having a longitudinal slot therein, the ends of said wall being closed by the respective plates; a plurality of coaxial connectors for coupling said switch to the respective lines, each of said connectors having a projecting contact pin extending within said body, one of said connectors being centrically located in the end plate, the remaining connectors being positioned in said wall in a plane passing through both the wall slot and the wall axis; a cylindrical member with one end engaging the cover plate recess, the other end of the cylindrical member being conically shaped with a hole in the apex thereof for engaging the contact pin of the end plate connector; and a slidable assembly supported within said body including an operating handle with one end extending through the wall slot, and a movable contact arm fastened to the opposite handle end and slidably engaging said cylindrical member for selectively making with the respective projecting contacts of the wall connectors.

6. A multiposition switch for selectively connecting a plurality of coaxial lines comprising a hollow body having a cylindrical wall with a longitudinal slot therein, and an end plate closing one end of said wall, a plurality of coaxial connectors for coupling said switch to the respective lines, each of said connectors having a projecting contact pin extending within said body, one of said connectors being centrically located in the end plate, the remaining connectors being positioned in said wall in a plane passing through both the wall slot and the wall axis, a cylindrical member ccaxially located Within said body, and

7 e' sndabie assembly supported within said body 'upoii said cylindrical member and including an secretin handle withone end extending through the wall slot 'anda movable contact arm for se l'ect-iyely making with the respective projecting contact pins of the wall connectors, one end of said contact arin being fastened to the opposite end or said handle, the other arm end having a recess therein for engaging selectively the -re i sp'ectiveiwail connector c'on'tact pins'as a "detent,

and spring loop interposed between said arm ends to insure adequate contact pressure.

3. A rndltiposition switch for selectively-connecting a plurality of coaxial lines comprising a hollow body having two end plates, each with a 'taperedaper'ture centri'cally located in the inner surface thereof, and a cylindrical wall having a longitndinal slot therein and ends closed by the respective end plates, a plurality of coaxial connectors for coupling said switch to the respective lines, each of said connectors having a projectingcon-tact pin extending within said body, one of said connectors being centrically located in the tapered aperture of each of the respective end plates, the remaining connectors being positioned in said wall in a plane passing through both the wall slot and the wall axis, a cylindrical member having conically shaped ends, each with a hole in the apex thereof for'engaging the contact pin of the-respective end plate connectors, a 'slidable assembly supported within said body by the cylindrical members,said assembly including an ope-rating handle with one end extending through the wallslot, a movable contact arm for selectively making with the respec-'- tive projecting contact pins of the Wall connectors, one end of said contact arms beingfastened to the opposite end of said handle, the other arm end-having a recess therein for engaging the wall coring-rotor contact pins as a detent and a'spring loop interposed between said arm ends'to insure adequate contact pressure.

8;--A mu-ltiposition switch for selectively con- 8 njecting a plurality of coaxial lines comprising a hollow body having an'end plate with a tapered aperture centrically located in the inner surface thereof, an insulating cover plate having a recess therein, and a cylindrical Wall having a longitudinal slot therein and ends closed by the respective plates; aplufality of coaxial connectors for coupling said switch to the respective lines, each of said connectors having a projecting contact pin extending within said body, on'eof said connectors being centrically located in the ta-"- p'ered aperture of the end plate, the remaining connectors being positioned in said wall in a plane passing through both the wall slot and the wall axis; a-cylindrical member with oneend engaging the cover plate recess, the other end of the cyl-im drical member being conically shaped with a hole in the apex-thereof for engaging thecontact pin of the end plate connector;- and a slidab1eassem bly supported within said body by the cylindrical member, said assembly including an operating handle with one end extending through the wall siot, a movable contact arm forselectively making with the rwpective projecting contact pins of the wall connectors, one end of said contact arm-2s being fastened to the opposite end of said handlathe other arm end having a recess therein for engaging the wall connector contact pins as a detent and a spring loop interposed between said arm ends to insure adequate contact pressure.

GARDINER GREENE.

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

"UN ITET STATES PATENTS Number Naine one 1,013,35 Hastings Feb. 20, 1912 1,443,098 Smith Jan. '23, 1923 1,997,158 Thomas Apr. 9, 1935 2,426,136 Dow a. Au 26-, 194'?

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