Modular coaxial switch

C. W. CONCELMAN modular coaxial switch

March 5, 1968

Filed Aug. 13, 1955

3,372,349

Sheets-Sheet 1

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INVENTOR

CARL W CONCELMAN

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ATTORNEYS.

March 5, 1968

3,372,349

C. W. CONCELMAN modular coaxial switch

Filed Aug. 13, 1955

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ATTORNEYS

March 5, 1968

3,372,349

C. W. CONCELMAN

MODULAR COAXIAL SWITCH

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ATTORNEYS.

3,372,349

C. W. CONCELMAN

MODULAR COAXIAL SWITCH

March 5, 1968

Filed Aug. 13, 1965

Sheets-Sheet 4

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FIG 9

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FIG.ID

FIGI I a

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FIGIIc

FIGII b

INVENTOR CARL W. CONCELMAN

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ATTORNEYS.

3,372,349

Patented Mar. 5, 1968

United States Patent Office

3,372,349 r , ^M0„^DULAR COAXIAL SWITCH

Carl W. Concelman, Danbury, Conn., assignor to Amphenol Corporation, Broadview, IB., a corporation of Delaware ^r

Filed Aug. 13, 1965, Ser. No. 479,458

Claims. (CI. 333—7) , ^Tbls “^vention relates generally to electrical switches roi high frequency circuits, and more particularly to radio frequency coaxial switches of a modular design wherein the electrical and mechanical characteristics of the switches may be selectively established through the use of a plurality of interchangeable modules.

. High frequency coaxial cable switches are well-known in the art for selectively switching radio frequency energy trom an input coaxial connection to either one of two output coaxial connections. In order to meet electrical requirements for various applications, several basic types of radio frequency switches have been developed. For instance, it is sometimes desirable to short-circuit the unused transmission line connection to the switch housing in order to electrically isolate it from the adjacent switch wh^T¹⁸’ ^eS?^ecia!^{ly at very hig}h radio frequencies here the wavelengths of the energy involved are of the order of magnitude of physical dimensions of the switch components. However, for other switching applications, it nprfpH^een^^OU_f^{nd advant}ageous to terminate the disconcuff A&lt;tdV° ^f^®^qu?^ncy transmission line in an open circuit. Additionally, m such applications as video switchin® superior electrical performance has been obtained by ter? Xnnni^{eaCh C}°^nl?^{ection in} its characteristic impedance hen not connected to another transmission line. It is also often desirable to present a dummy load for transmitter ^adjUStmOTts hy terminating a transmission line to chassis potential through a resistor of a predeter“ddffte^^a8f^nitUr^e· °?^{er sw}.^itchinS applications require the able tn ^a-^f°^Urth .^coaxial connection in order to be lines Tn the ^{SWltCh dl}®^{erent pairs} of transmission lines. In the prior art, each of the preceding different ‘ ^b- ^^{ired a} separltiS

Further, radio frequency coaxial switches of the same reZiredSnt^h⁶⁰· 7 ^{electrical charact}eristics often require different physical arrangements of the external 45 fetors which receive the coaxial transmission lies Some applications, of coaxial switches physically require whilXher⁰ n^S ‘° ® °^Π °^{e Side} °^{f tbe sw}“^{ch b}°dy, while other uses make it desirable to mount the inpu fr^HJh⁸¹⁰²¹/¹! ?^{Π the opposite si}de of the switch body 50 h°m ^the output imes. Heretofore, switch bodies of difRrent mechanical configurations were required to obtain ^cord^ κχ,ΐχιs ar “

A more specific object of the invention is to provide a new improved electrical switch of simple and inexpensive construction for selectively connecting a first high frequency signal transmission line to either of two other such ⁶⁰lected manner™¹”^{311118 Unconnected} line in a prese. A further object of this invention is the provision of an improved high frequency transmission line switch which includes a switch body so constructed as to permit the ⁶⁵association of line connector components therewith in a variety of arrangements.

The instant invention contemplates a modular construction including a switch body and a minimum number of parts which may be readily interchanged to produce a large number of different switches, thus eliminating the requirement for a separate mechanical design for each «tterent type of switch required. A better understanding ^{its many adva}“tages will be gained trom the following detailed description of certain embodi^{ln the} accompanying drawings, in which:

FIGURE 1 is a perspective view of an assembled switch housing and switch actuator mechanism;

Kj^{ure 2} is an exploded view of the switch housing, ^t02?^tb®^r a shorting termination module;

IGURE 3 is a transverse cross sectional view through a center portion of the assembled switch housing including a shorting termination module· ⁸ /Sta” °' » “·«>' ₍h,F?^Gy^{RE 5 a} longitudinal cross sectional view through a central portion of the assembled switch housmg, together with the switch actuator;

FIGURE 6 is a perspective view of a non-shorting tertheⁿ_s^awitch^m°^{dU 6 WhlCh may be USed in} conjunction with me ovviicn, tion mMute;⁷ * * ^VfeW °^{f a resistor} ‘™^aFIGURE 8 is a perspective view of a transfer terminaFTCTn?^Up ^^{bich may be used with the sw}itch;

tion lineT^MOU^^ ^sec module; figure 7, of a resistor termination

FIGURE 10 is a cross sectional view of a transfer ter30 URE 8°-ⁿa“d ^{Uken aI}°^{nS SeCti}°^{n Iine 10—10 of FIG}' for^nnecte fitri ~^{C Vari}°^{US possible} orientations

FICTtpr ΐ m ^8S °^{n the asse}mb!ed switch.

a \^{1 lustra}tes a switch housing 10 comprising

A ^C°wTr ^{Plate 12} connected to a main body block 14 3o A switch actuator 15 is mounted on a side of the switch o^OUrective^0IeT'‘^dt^lnCl1^{UdeS 3 h}°^{Using 16}’ ^and terminals 17 to receive electrical actuating signals from a control plate^C%^{nOt Sh0Wn}’ Permanently attached to connected 40 Fnn^{4 12} T ^connector fittings 18 and 20, including female inner conductors 22 and 24, which receive coaxill trans mission lines. Shown attached to connector PlTte 12 bv’ suitable fastening means is a termination module 26 to Plat u^eand^ntlydTj,^bel^{in greater} detaiL Connector y J the phte. ·»»·Λ aperlures 34 and 3S are oonneX are connected to Id ^Y ?^nsuIatinS inserts 46 and 48, ing blades or reeds SO^aM 51 ^Sj^PP°^rt ^eIongated switchlocated on the side of plate 12, receives suiteffie fastening ^{means duf}m^g attachment of switch actuator 15 ^§ to n /° ^and₁,^{:>1 3Γ}® °^{f a design which} has been found SnfrT^{1 SWitCh C}°^ntaCt characteristics? The mpered and angled configuration of the free ends of the switching b.ades is of particular interest, as it enables the blades to be used with any one of a plurality of termination modules having differing mechanical shapes and electrical characteristics. The blades are constructed of a flexible metallic material such as beryllium copper

3,372,349 tion module 99 is shown in position to be attached to connector plate 12. The rectangular base portion ICO will fit into and substantially fill receiving slot 40 of connector plate 12 and bores 102 will communicate with holes 54 to receive suitable fastening means, such as screw 104 and lock washer 106. One skilled in the art will understand that screw 104 will not only fasten the termination module in receiving slot 40, but will also provide mechanical strength to the connection between connector plate 12 and the main body block 14 by being tightened in the threads of bore 64.

Integrally formed with the base portion 100 of the shorting termination module are two vertically extending contact portions 108 and 110. When module 99 is attached to connector plate 12, the two vertically extending contact portions fit through aperture 36, and extend into channel 56 to embrace the two free end portions of the switching blades 50 and 51. As clearly shown in FIGURE 3, in normal application of the. switch, blade 50 will contact the respective contact portion 108 of the shorting termination module, thereby shorting the unconnected transmission line to chassis potential. The remaining switching blade 51 will be in contact with the contact sleeve 98 of the connector module. When the switch is actuated in a manner subsequently to be described, the normally shorted switching blade 50 will be placed in contact with contact sleeve 98, while the reremaining blade 51 will be shorted against its respective contact portion 110 of the shorting termination module.

The vertically extending contact portions 108 and 110 of the shorting termination modules may be made of conductive material such as brass, and finished with a plating such as gold. The contact portions are shaped as longitudinal sections of a cylinder which has the approximate 35 diameter of apertures 36 and 60. When the contact portions extend into channel 56, the flat inside surfaces of the contact portions fit flush with the side walls of the channel 56 in order to present a channel of constant width between the enlarged end portions 58 and 59.

It will be understood that termination module 99 is interchangeable in position with connector module 75, and that the internal dimensions of channel 56 will remain constant in either position of the termination module. This will allow the mechanical configuration of the 5 present switch to be changed without disturbing the basic electrical characteristics of the switch.

The switch actuator 15 enclosed by housing 16 is shown in detail in FIGURES 4 and 5, wherein a wound wire, coil 112, supported by support block 114, is conductively connected to terminals 17 by the leads 116. Preferably, the wire coil 112 is covered with an insulating layer of tape. A metallic core 118 extends longitudinally through the center of the wire coil 112 and is supported by core support 120, which is made of insulating material. Rockably mounted with respect to coil 112 and core 118 is a clappei 122, which is made of a material that responds to magnetic forces and which includes an elongated clapper arm 124 with an L-shaped slot 126 provided therein. As best seen from FIGURE 5, a spring 128 is disposed in spring receiving hole 74 in the main body block 14 to normally bias clapper arm 124 against stop arm 129.

A base plate 130 is secured to switch 10 by stud 132 which fits through bore 134 of support block 114, aperture 136 in the base plate, and tapped hole 70 in body 65 block 14. Switch actuator 15 is further connected to switch 10 by suitable fastening means 138 engageably fitting in threaded bores 55 and 68, shown in FIGURE 2, while also fitting through bore 140 in support 120 and slotted portion 142 in base plate 130. Spring 128 extends through 70 hole 143 in base plate 130, and switch actuating pins 144 and 146 extend into channel 56, slidably. fitting through apertures 147 and through holes 72 provided in the side of main body block 14. Actuating pins 144 and 146 are made of a non-conducting material, such as a 75 polymer of trifluorochloroethylene or tetrafluorocthylene, ³ and coated with a material such as gold to assure good contact characteristics.

Main body block 14 has a channel 56 with enlarged end portions 58 and 59 in order to receive the movable switching blades 50 and 51 when block 14 is attached to connector plate 12. Channel 56 and the enlarged end portions extend only approximately halfway into main body block 14 in order to provide a switching chamoer defined by conductive walls when the switch is assembled. An aperture 60 extends through channel 56 and j communicates with the base of a receiving slot 62, which has the same dimensions as slot 40 and extends transversely across a central portion of the upper face of the main body block 14. The walls of both the aperture and the receiving slot 62 may be chamfered to permit ease of entry for a termination module. Four threaded bores 64 are provided in body block 14 and are spaced to communicate with holes 54 in connector plate 12. to receive suitable fastening means during the. connection of a termination module. In addition, roll pm holes 66 are aligned with pin holes 52 during assembly of the switch in order to receive fastening pins 28. On the side of main body block 14, threaded bores 68 and 70 are provided for the attachment of switch actuator 15, while actuating pin holes 72 and spring receiving hole 74 are included to receive elements of the switch actuator, as will be subsequently described.

It is well-known that the characteristic impedance of a circular sectioned coaxial transmission line is a function of the ratio between the inner diameter of the outer conductor and the outer diameter of the inner conductor and of the interposed dielectric. Similarly, the impedance of the assembled switch is dependent upon the dimensions and geometrical configuration of channel 56 and switching blades 50 and 51 with air as the dielectric. Thus, if the cross sectional dimensions of the channel are selected in conjunction with a proper design of blades 50 and 51, the assembled switch will present a desired characteristic impedance to a connected transmission line. As connector fittings 18 and 26 provide an approximate impedance match between the transmission lines attached thereto, a relatively low voltage standing wave ratio will then result from the switch.

Further considering FIGURE 2, a connector module 75 has a rectangular base portion 76 of .a modular construction to fit in mating relationship with and subsUintially fill receiving slot 62, or in the alternative, slot 40. A fastening screw 78 and lock washer 80 are used with each bore 82 to releasably connect the base portion 56 in either receiving slot. Although a female N-type connector fitting 84 is illustrated in the drawing as extending from base portion 76, it will be understood by one skilled m the art that any other standard connector fitting design, such as a TNC or a BNC connector fitting, may be utilized. In this way, the switch 10 may be adapted to be used with any standard radio frequency coaxial cable connector plug.

The construction of the connector module 75, together with its relationship to the assembled switch, may be best understood by reference to FIGURE 3 wherein module 75 is secured within receiving slot 62 of body block 14. An insulator 86, made from an insulating material, such as polytetrafluoroethylene, is secured within the metallic connector fitting 84 by means of inturned flanges 88 In addition, a female contact 90 is securely held m place within insulator 86 by means of knurled portion 92, and a metallic bushing 94 is secured within connector fitting 84 by means of a flanged portion 96. Press-fitted upon the inwardly extending end of contact pin 90 is a contact sleeve 98, which may be fabricated from material containing gold and silverplated in order to provide a terminal with satisfactory characteristics for use between switching reeds 50 and 51 within channel 56 of the switch.

Referring again to FIGURE 2, a shorting termina40

3,372.349 5 and are of a diameter larger than the width of the L-shaped slot 126 provided in clapper arm 124. Thus it may be understood by one skilled in the art that when an energizing current is supplied to wire coil 112 through terminals 17, armature 118 becomes energized and magnetically attracts clapper 122. As the clapper rocks about its axis, clapper arm 124 overcomes the bias of spring 128 to force switch actuating pins 144 and 146 to displace switching blades 50 and 51 from their normal positions. Of course, when coil 112 is de-energized, the clapper 122 and clapper arm 124 return to the position shown in FIGURE 5, thus allowing the flexible switching blades to return to their normal positions.

In order to utilize the switch in an environment which requires the unconnected transmission lines to be terminated in an open circuit, a non-shorting termination module 148, shown in FIGURE 6, may be connected to the switch. The non-shorting termination module is constructed in a manner similar to that of the shorting termination module 99, with the exception that a liner of insulating material 149, such as glass cloth thermo-setting electrical tape, is fastened to the inside flat portions of the vertically extending contact portions 150 and 152. Thus, when one of the switching blades is not connected to the contact sleeve 98, the blade will be insulated from the switch housing to present an effective open circuit to the unconnected coaxial transmission line. As the base portion 154 is of the same modular construction as the base portion 100 of the shorting termination module, it will be apparent that the non-shorting termination module 148 may also be reversed in position with the connector ' module 75.

As previously discussed, in the case of video switching and in adjustment for transmitters or receivers, it is often desirable to terminate the unconnected transmission line through a predetermined impedance to chassis ground. ' This may be accomplished by utilizing a resistor termination module 156..The construction of such a module 156 is shown in .detail in FIGURES 7 and 9, wherein a square base portion 158, of the same modular construction as those base portions previously discussed, is provided with a circular lip 169 which defines a cylindrical cavity in the base portion 158. Press fitted into the cylindrical cavity is an insulator insert 162, made from a material such as polytetrafluoroethylene, and which includes two narallel grooves 164 and 166. Disposed within each such groove is a resistor 168 of a. predetermined impedance. A U-shaped contact 170, including two contact portions, is held by stud 172, which is in turn attached to insulatorinsert 162 within a suitable aperture. One terminal of each of the resistors 168 is soldered to contact 170 while ⁵⁰the remaining pair of resistor terminals is connected to the conductive circular lip 160. Hence, it may be seen that the resistors 168 are connected in parallel between the U-shaped contact 170 and base portion 158 in order to obtain a required power rating for the switch within ⁵⁵the space limitations of the modular construction of the switch.. For.instance, two one-fourth watt resistors might be utilized in order to obtain a one-half watt rating for the switch.

Assuming that a connector module 75 has been inserted 60 and attached to receiving slot 62 of the main body block 14, contact sleeve 98 will be centrally disposed between switching blades 50 and 51, as shown in FIGURE 5. It will thus be understood that when resistor termination module 156 is connected in receiving slot 40, the arms of 65 contact 170 will embrace the free end portions of the switching blades 50 and 51. In either position of the switch, a switching blade will be in contact with a respective arm of U-shaped contact 170, thereby terminating t¹-- -------- ., . . · ; 2___ through parallel resistors 168. Any of a plurality ofvalues for resistors 168 may be utilized in accordance with the requirements of a particular switching environment. Further, the modular construction of resistor termination termination module and the connector module 75, and in case of a defective resistor, module 156 may easily be removed and replaced with a new module.

Instances sometimes arise wherein four radio frequency coaxial transmission lines must be selctively switched in order to connect two pairs of transmission lines in each position of the switch. This may be accomplished in the instant invention by utilization of a transfer termination module 174. As best shown in FIGURES 8 and 10, termination module 174 includes a rectangular base portion 176 of the same modular construction as the termination modules previously discussed. Integrally connected to base portion 176 is a rearwardly extending connector fitting 178, shown in these drawings as a conventional N-type connector, although it will be obvious that other conventional types of connector fittings may be utilized. An insulating insert 180, preferably made of insulating material such as polytetrafluoroethylene, is fitted into an open · ing provided within the base portion 176 and is locked in place by flanges 182. Formed integrally with base portion 176 is a circular conductive extension 184 which extends outwardly to provide a secure mechanical fit into either aperture 36 or 60 of switch 10. Because of a knurled portion 186, an elongated female contact pin 188 fits tightly within insert 180, and a U-shaped outer contact ISO, which is similar in structure to contact 170 utilized in combination with the resistor termination module, is securely fastened within a slot provided in insert 180 by means of a fastening stud 192. Therefore, an electrical path for radio frequency energy is provided from female contact pin 188 to the outer U-shaped contact 190. In a manner similar to the resistor termination module previously discussed, the U-shaped outer contact 190 embraces the switching blades 50 and 51 in such a manner that blade 50 is normally in contact with its respective outer contact portion, thereby normally connecting one pair of transmission lines, while the remaining switching blade is disposed against contact sleeve 98 to electrically connect a second pair of transmission lines. Thus, when actuated by actuator means 15, the blades will be disposed to connect two different pairs of transmission lines.

Transfer termination module 174 is designed in a manner similar to the previous modules discussed, in that it is interchangeable with connector module 75 in order to provide the advantage of flexible mechanical design of the switch.

As shown in FIGURE 11, the mechanical configuration of switch 10 may be established through the proper selection and orientation of a termination module. FIGURES 11A and 1 IB illustrate the reversibility of connector module 75 and termination modules of the present invention, while FIGURE 11C shows the utilization of a transfer termination module 174.

It will then be apparent from the foregoing description that a switch constructed in accordance with the present invention has the advantage of being simple and inexpensive to manufacture, while additionally providing for greater flexibility in design. For example, the basic switch may be utilized to provide a plurality of different mechanical connector arrangements as shown in FIGURE 11. Additionally, a plurality of switches with differing electrical characteristics may be provided by utilizing the basic switch with a selected one of the described termination modules. This novel design, which makes interchangeability of parts feasible and provides for ease of assembly of the switch in accordance with any selected electrical characteristic, presents a distinct manufacturing advantage. Also, the reduction of the number of basic parts of the -------- -· -, -------j _g switch results in a more rugged, yet less expensive, radio the unconnected transmission line to chassis ground 70 frequency coaxial switch.

... _t .. --- - - It will be apparent to those skilled in the art that various other modifications within the spirit and scope of invention are possible. Therefore, the invention should not be deemed to be limited by what has been shown and de40 module 156 makes it feasible to reverse the places of the 75 scribed herein by way of example.

3,372,349 the remaining ones of said apertures being disposed on opposite sides of said slot, first and second connector fittings extending through said remaining ones of said apertures and being secured to said connector plate, each ot said connector fittings having an outer end portion adapted for coupling to a transmission line and an inner end including a conductor being insulated from said plate, first and second switching blades connected respectively to said conductors of said connector fittings and extending longitudinally along said elongated connector plate in spaced relation to the inner surface of said connector plate, the free end portions of said switching blades remote from said conductors being disposed near the central portion of said inner surface of said connector plate, a main body block connected to said connector plate and having an inner and an outer face, said block having a channel with enlarged end portions in said inner face for receiving said switching blades and further having a slot extending transversely across a central portion of said outer face which communicates with said channel by means of an aperture through said block, a connector module including a base portion adapted to be received in and to substantially fill either of said slots, said connector module having an outer end portion adapted for coupling to the transmission line and an inner end portion including a contact which is disposed between the free end portions of said switching blades, a termination module including a base portion which fits into and substantially fills the remaining slot and further including two vertically extending contact portions which embrace the free end portions of said switching blades, and means for detachably connecting said connector module and said terminal module in said slots.

4. An electrical switch for high frequency circuits comprising an elongated connector plate having a slot extending transversely across the central portion of its outer surface and having three apertures therethrough, one of said apertures communicating with the base of said slot and the remaining ones of said apertures being disposed on opposite sides of said slot, first and second connector fittings extending through said remaining ones of said apertures and being secured to said connector plate, each of said connector fittings having an outer end portion adapted for coupling to a transmission line and an inner end including a conductor being insulated from said plate, first and second switching blades connected respectively to said conductors of said connector fittings and extending longitudinally along said elongated connector plate in spaced relation to the inner surface of said connector plate,, the free end portions of said switching blades ⁵⁰ remote from said conductor being disposed near the central portion of said inner surface of said connector plate, a main body block connected to said connector plate and having opposed inner and outer faces and opposed lateral faces, said block being provided with a channel for receiving said switching blades in said inner face and with a slot extending transversely across a central portion of said outer face, said block further being provided with a first aperture extending through said block to communicate with said channel and said slot and with a pair ot second apertures extending through said block from one of said lateral faces to said channel, a connector module including a base portion adapted to be received in and substantially fill either of said slots, said connector module having an outer end portion adapted for coupling to a transmission line and an inner end portion including a contact element which is disposed between the free end portions of said switching blades, a termination moduie including a base portion which fits into and substantially fills the remaining slot and further including two vertically extending contact portions which embrace the free end portions of said switching blades, means for detachably connecting said connector modules and said terminal modules in said slots, and actuator means connected to said one of the lateral faces of said block and including