US3153129A - Coaxial switch - Google Patents

Description

COAXIAL. SWITCH 2 Sheets-Sheet l Filed OCT.. 24, 1960 Nw 0 A w av w R o @QW N uw @1,154 S1 am 1 su Oct. 13, 1964 Filed O Gt. 24, 1960 s. LAPIDUs ETAL 3,153,129

coAxIAL swITcH 2 Sheets-Sheet 2 A TTO/VEYS T-type,fembodying features Yof our invention;` i

FIG. 2 is a fragmentary view explanatoryof a detail;v

. FIG. 3 is a section takenapproximately inthe vplane of l the line 3--3 of FIGA;

` 3,155,129` CAXIAL SWITCH K Solomon "Lapidus, Flushing, and Marc Sheldon, New

York, NX., assignors to Bogart Manufacturing Corporation, Brooklyn, NX., a corporation of New York Filed' 0er. 24, 196th, Ser. No. 64,347

18 Claims. (Cl. 200,-153) This invention relates to electrical switches for high frequency power, and more particularly to aj three-port coaxial switch. l i Y lfhe generalobject of the invention is to improve coaxial switches, especially T-type coaxial switches fo handling alarge amount of power. t

A more particular-.object is to provide improved'control mechanism for operating such a switch. A st ill more specilic object is to provide a manually operable handle which turns a halfrevolution .and which is so mounted thatit pointsin the direction of thebranch of the switch lwhich has been connected ormade operable. l

Still another Objectis to provide operating mechanism which is compact, and much of which is housed inside the `coaxial conductors, withoutaffecting their electrical characteristics. Y

The switch is of the T-type and includes a lslidable element which isrmoved axially toward one branch or the opposite branch of the T. One object of the inven- United States Patent O ice Patented (Bet. 13, lgd

. to connect the common inner conductor 24 to one or the FIG .5 the slidable element 22 is in its right position, and

invention resides in the coaxial switch elements and their relation one to another, as are hereinafter more particularly described in the followingspecilicaticn. VThe specication is accompanied by drawings in which:

FIG.` l is a section through a coaxial switch of the FIG. 4 is a section through the slidable element;

FIG. 5 is an incomplete sectionsimilar to FlGfl but showing the switch shifted to the right instead of the left branch;

FIG. 6 .is a partial plan view taken in the plane of the lineS-S of FIG. 4, and drawn to reduced scale; and

' FIG. 7 shows an insulation bead for supporting the in' ner conductor. e

Referring to the drawing, the coaxial switch comprises ,v a T-shaped housing 12 providing the hollow-outer conductor 14 of the stern or common portion, and thehollow outer conductors lo'and 18 of the two aligned branches of the switch. In preferred form these outer conductors Yare cylindrical.

There is a common inner conductor 24 running through l `the outer conductor 14, and terminating at its inner end in a ring 2li which is coaxial of thebranches lo and 18.

Thereis an inner conductor element 22 which is slidable through :the ring 20. Therbranch'lohas a stationary inner conductor 2&5, and the branch 18 has a stationary innerconductor 28.V As usualptheinner-conductors'are preferably cylindrical and coaxial with the outer =con ductors.` "A

'The innerend 3i) of conductor 26 and the innery end .32 of conductor 28;V are located at asp'acing lfrom'the common conductor or" ring 20 approximating thef'length v(it) other-of the-branch inner conductors 26 and 28. In FIG. l the slidable element 22 is in its left position, and connects the common conductor 24 to the branch conductor 26, While the other branch conductor 2 is isolated.r In

connects the common inner conductor 24 to the branch inner conductor 28, while the other branch inner conductor 26 is isolated.

An insulation rod 34 extendsthrough the aligned inner conductors 26 and 2S and the slidable element 22. This rod 34 is secured to the slidable element 22, but itis freely slidable in the stationary inner conductors 26 and 2S. Thus the rod 34 may be used to move the element 22 between its left hand and right hand positions.

For this purpose the switch in the present case is provided with a handle 36 which is operatively connected to the rod 34. More specifically, 'a part of therod has gear teeth to form a rack 3S. A small diameter gear 40 is housed in one of the branch inner conductors, in this case the conductor 2S, and meshes with the rack 38.` An insulation shaft 42 extends from the gear toy a point outside thev housing for rotation by the handle 36.

Referring to FIG. l, handle 36 is connected through a shaft 44 to a gear 46. This meshes with a pinion 4S operatively connected to the outer end of shaft 42. The `step-up gear ratio between gear` 46 and pinion 48 is so selected that the slidable element 22 is moved all the way to one or the other branch conductor by a half turn of the handle 36. Moreover, in preferred form the handle 36 is so mounted that it points in the direction of one branch or the other, an`d specifically to that branch which has been connected or made operative. In FIG. l handle 36 points to the left, and slidable element 22 has beenl moved to the left. In FIG. 4 handle 36 points to the right, andv slidable element 22 has been moved to the right. 1W i. l,

The slidable element 22 is a hollow cylinder. It is made of a 'resilient conductive material, and in the present case it is made of heat `treated beryllium copper, which preferably is vplated with a hard chromium-plate finish. The end portions 50 .and 52 are relatively thin walled and longitudinally slotted to make the same resiliently yieldable. Thefparts 30 and 32 of the stationary inner conductors constitute cylindrical seats which slidably receive the end 50 or S2 respectively. The ring zwslidably receives either end Sii or 52 of the slidable element. When, as in the present case, the midportion is'rigid or non-yieldable, it is preferably somewhat `smaller in diameter'than the end portions 50 and 52, so that it will readily slide through the ring 2i?. However the seats 30 and 32 'and the ring 26 are dimensioned lto receive the slotted parts of the element 22 with a snug lit which provides a good electrical contact.

The rigid or non-slotted center portion of element 22 receives bushings which are internally dimensioned to re- Vceive theA insulation rod 34, and it -is secured thereto by means of ,transverse dowel pinsg56. v h

It will be observed that the ends of the slidable element are beveled to facilitate entering theseats.v Of coursethe terhto Vthe hollow cylindrical ring 20. With the present i arrangement the slidable element always yields in compression, that iis, by contraction, instead of being expanded in one position and contracted in the other, as'

would be the case if the seats were received inside the slidable element.l

The insulation shaft 42 preferably has ats at both ends. The flats 60 at the outer end preferably are perpendicular to the flats 62 at the inner end, and these dats are received slidably between mating flats, and thereby serve to transmit torque to the shaft at thellats 60, and from the shaft to the rack gear 40 at the ats 62. This arrangement has the advantage that the flats function somewhat as universal joints, and thereby accommodate any slight misalignrnent of the shaft.

Considering some features of the switch in greater detail, the handle 36 may be a standard handle available for purchase in the commercial market. That here shown is made by Barkelew Electric Manufacturing Co. of Middletown, Ohio.

The handle has a depressible thumb button 64 which maybe depressed against a compression spring 66. It is connected to a lever 68 pivoted at 70, and the opposite end of which is connected to a lock pin 72. The end of this may be received in either of two diametrically related holes in a cover plate 74, thus anchoring the handle in one end position or the other.

The switch housing 12 as cast, preferably includes an integral platform 76 on which the operating mechanism is mounted. This platform may be square or rectangular in configuration, to provide mounting holes for the switch, shown at 77 in FIG. 6. vIt receives a lower spacer 78 and a mounting plate 80 (FIGS. l and 5) which may be circular in outline. The gear 46 and pinion 48 are received between the platform 76 and the mounting plate 80. The latter supports another and wider spacer 82, and the cover plate 74, which again preferably are circular in outline. The superposed parts 78, 80, 82, and 74 are secured together by appropriate screws, but the section of FIG. 1 happens to pass through locating dowels,

vof the switch.

Referring to FIG. 6, the shaft 44 carries an arm 84. This has independently adjustable stop screws 86 and 88. Screw 86 bears against `a iixed stop .90 when the switch is in the position shown in FIGS l and 6,- and the screw 88 bears against a similar iixed stop 92'when the arm 84 has been turned 180 degrees, or is in the position shown in FIG. 5. One end 94 of arm 84 is reduced in dimension and passes diametrically through a mating hole in shaft 44. It is keyed in position by a pin 916.

It is frequently desired to interlock the switch with other mechanism, and to indicate its position on appropriate pilot lamps or indicators, For this purpose the present switch carries four precision switches or s'o-called rnicroswitches. superposed at 98 and 100. On referring to FIG. 6, it will be'seen that there are another two such switches at 102, the lower switch" being concealed by the upper switch. Each switch has an operating pin engaged by a feeler or tab, as is usual with such switches.

The Varm 84 has a pair of opposed, independently adjustable screws 104 and 106. The head of the screw 106 is large enough to simultaneously engage the tabs of the superposed switches v98 and 100, and similarly the head of screw 104 is large enough to simultaneously en- 'gage the tabs ofthe superposed switches at 102. It will be understood that the number of switches may be varied, dependingv on the needs in any particular case. The wiring from the switchesmay be led to a multiple pin detachable connector, the female-element of which is located in atting or holder 110, which is secured to the upper spacer 82 previously referred to.

j nating in a female socket 166 (FIG. 1).

4 closed cylindrical portion 112. This is a matching stub, and is appropriately dimensioned for that purpose.

Inner conductor 26 is located within outer conductor 16 by insulation discsor so-called beads 114 and 116. These may be made of Teflon. They are received in mating annular channels in the inner conductor, and to permit assembly, the beads are slit as shown at 118, 120 in FIG. 7. The material is flexible enough to permit opening of the split disc to be received over the necked portion of the inner conductor.

^ Similarly, the inner conductor 28 is supported by insulation beads 122 and 124, and the inner conductor 24 is supported byinsulation beads 126 and 128. In the case of conductor 24, it is important to orient the same properly so that the axis of ring 20 will remain'aligned with the branches. For this purpose the outer periphery of bead 128 is keyed to the housing at 130, and-inner conductor 24 is keyed to the bead 128 by means of adiametrical pin 132 (FIG. 1) received in a hole 129 (FIG. 7).

The inner conductor carries metal discs `134 and 136 which are brazed to the inner conductor. They are matching rings to help match the impedance of the common part 14, 24 to thefimpedance of a standard coaxial line.

It also is importantthat the inner conductor 28 be properly oriented with respect to the branch 18, and for this purpose the bead 124 is keyed at 140 to the inner conductor 28, and the periphery of the bead is keyed at 142 to a ange plate 144 secured to flange 146 forming a part of the housing.

The particular switch here shown is for use with coaxial line or plumbing of large dimension, specifically standard 31/s inch coaxial line. The connections are standard E.I.A. tiange connections. The branch 16 has an integral ange 150 which receives a body extension 152 having nanges 154 and 156. This extension is employed because the inner structure 26 terminates in a female socket 158, which is housed within the body.

At the end of the other branch the conductor 28 terminates in a male end 160, or so-called bulletf This has longitudinal slots, as will be seen at 162 in FIG. 6. The bullet is somewhat resilient, but is made of brass instead of beryllium copper like the slide `22, and it is reinforced by an internal helical spring 164 (FIG. 1). No body extension is used, because the b-ullet projects from the body.

The common inner conductor 24 is here shown termi- The body has a nange 168 which receives the tlange170 of a body ex- In FIG. 1 there are two such switches 1 f tension 172 like the body extension 152. Thus the socket 166 is housed within the body. It will be understood that either a male bullet or a female socket may be provided at any of the three ports, as may be needed for any particular installation. Whenever a female socket is provided the body extension is added. In this way one cast body serves for any combination of male and female connections.

Referring to FIG. 4, the slidable element 22 has an unslotted center portion 200 which is somewhat thicker than the remainder of the element. This portion receives a pair of stepped bushings 202 having inner diameter dimensioned to receive the insulation rod 34. The rod is secured in position by diametrical pins at S6. The end portions are slit as far as the middle portion 200, and a zone .at 204 adjacent the thickenedmiddle portion 200 is preferably thinned somewhat, thereby increasing the yieldabil- 1ty of the end or contact .portions of the slidable element.

The diameter ofthe midportion 200 is somewhat less than that of the end portions, and this reduced diameter is Apreferably carried `throughjthe zone 204 on each side of the midportion 200. y j

In the specific case here shown the slidable element 22 has 16 slots` uniformly distributed around its periphery, as shownin FIG. 3. Eachlslotis 0.032 inch wide.

The cylindrical ring 20 is longerjthan the depth of the seats 30 and 32. There is accordingly more surface cony, 30 db minimum.

tact at than at either 30 or 32. To maintain uniform electrical contact, the diameterot seats 3) and 32 is somewhat less than that'ofrthe ring 20, so that there is somewhat greater contact` pressure where the area is less, thu compensating for the reduced contact area. Y

The rod 34 is made of insulation, preferably Teilen. The rack gear 40 may be made of metal, preferably starnless steel. It has an adapter il (FIG. 2) with flats at 62 (FIG. l). 'I he insulation shaft 42 is made of an insulation material of suicient strength. Pinion 48 (FIG. 1) is received on the' small end of a coupler, the larger end. of which has a flattened hole or socketwhich receives the flats 6@ of shaft 42. In the particular switch here shown the gear ratio between gear 156 and pinion 48 is six to one, so that a half revolution of handle -3d turns the insulation shaft 4Z three revolutions. i0 is so selected that these three revolutions move the rack and the slidable elementtZZ all the way from one end v positionV to the opposite end position.

The diameter of rack gear itl is preferably kept smallso This is shown in FG. 2,' in which the rack 33 and its driving gear 4@ are fully housed within the inner conductor 28. These parts have no significant eiectV on the electrical elciency of the coaxial branch made up of inner `conductor 2h and outer conductor lid.

Most of the metal parts of theswitch are made of brass,

l and preferably are silver plated. However, the slidable ,for example, the Marmann quick disconnect flange.

The switchV was designed to operate overa frequency range of from 75.5 to-985 mc. and to handle up to 1G kw.

Vaverage power;v .The VSWR was not to exceed 1.1 maximum; the insertion `loss'not to exceed 0.15 db maximum;

and the isolation between branches 16 and 13 was to be ln actual practise the switch greatly exceeds these requirements, and it operates efficiently over ltheentire `frequency range of the transmission line. The

isolation maybe increased by lengthening the switch. v

The diameter of rack gear thatis `is housed .fully within the inner conductor ZS.

The switch maybe used in a pressurized line.` Forthis will be seen'in the drawing.

v The switch may be scaled down with appropriate modifications for lines of different size, for example 15/5 inch coaxial line.

It is believed that the construction and method of use, as well as the operation and advantages of our improved switch, will be lapparent from the foregoing detailed description. lt will also be apparent that while we have purpose the anges are sealed by the use of O rings, as,

shown and described the invention in a preferred form, vchanges may be made withoutdeparting from the scope of the invention, as sought to be deined in the following "claims In the claims the reference to theslidable element ,being slidable through a ringf is not intended lto exclude` an incomplete ring, or, any suitable passage extending transversely through the inner end of the common inner conductor. n

v1. Acoaxial switchcornprising a T-shaped housing providing the hollow outer conductors of a stem and two aligned branches, 'a commoninner conductor through/the stem terminating at `its inner end in a ring which is coaxial of the branches,` an inner conductor element passing through and slidablein ,said ring on the commonaxis of said branches, a' stationary inner conductor in each branch, with itsl inner end terminating at a spacing from the common inner vconductor approximating the length of the slidable element,` whereby the latter may beused to l connect said `common inner conductor to one orjthe other t to slide said rod longitudinally.A

of the branch inner conductors, means at the end of the' stem for connection to a coaxial conductor aligned with said stem, aligned' means at the ends of the branches for connection to coaxial conductors aligned with one another and with the branches, an insulation rod which is shorter than the combined length of the branches extending through both of said'aligned inner conductors and through'said slidable element, saidrod being secured to said element but being slidable in both of said stationary branch inner conductors, and means mounted on the side of one of the branches operatively connected to said rod the slidable element, whereby the latter may be used to connect said common inner conductor to one or the other of the branch inner conductors, means at the endofnthe stem for connection to a coaxial conductor` aligned with said stem, aligned means at the ends of the branches for connection to coaxial conductors aligned with one anotherV and with the branches, an insulation rod which is shorter than the combined lengthof the branchesfextending through both of said aligned inner conductors and through said slidable element, said `rod being secured to both of said elements but being slidable in said stationary branch inner conductors, a part of said rod having gear teeth to form a rack, a gear in one of the branches and meshing with said rack, and means passing through the sideof the said branchto rotate said gear.

3, A Vcoaxial switch comprising a T-shaped housing providing the hollow outer conductors of a sternV and two valigned branches, a common inner conductor through the stem terminating at its'inner end in a ring which is vcoaxial of the branches, an inner conductor element passing throughV and slidable in said ring, a stationary inner 'conductor in each branch, with its inner end terminating at a spacing from the common inner conductor-approximating the length of the slidable element, whereby the latter may be used to connect said common inner conductor to one or the other of the branch innerV conductors, an insulation rod extending through both ofV said aligned inner conductors and throughvsaid slidable element, said rod being secured to said element butbeing slidable in both of said stationary branch inner conductors, a part of said rod having gear teeth to form a rack,

a small diameter gear hcusedin one of the branch inner providing the hollow outer conductors of a stem and two Y aligned branches, a common inner conductor through the i stem terminating at its inner end in a ring which is coaxial of the branches, an inner conductor element passing through and slidable in said ring, a stationary inner conductor in each branch, with its inner end terminating at `aspacing from the common inner conductor approximating the length of the slidable element, whereby the latter may be used to connect said common inner conductor to one orthe other of thebranch inner'conductors, an in- V sulation rod extendingthrough said aligned inner conductors and slidable element, said` rod being secured to said element but being slidable in said stationary branch inner conductors, apart of saidrrod ,having gear teeth to forni" avrack, a small diameter gear housed in one of the branch inner conductors and meshing with said rack, said inner conductor' being cylindrical and said gear being so small in diameter that it does not project outside the cylindrical surface of said inner conductor, an insulation shaft extending from said gear to a point outsidekthe housing, a handle manually rotatable for about one-half revolution to point in the direction of one branch or the other, a gear turned by said handle, a pinion meshing with said gear and driving the aforesaid insulation shaft, the stepup gear ratio being such that the slidable element is moved all the way to one or the other branch inner conductor by a half turn of the handle and the handle acts as an indicator of the switch position.

A coaxial switch comprising a T-shaped housing providing the hollow outer conductors of a stem and two aligned branches, a common inner conductor through the stem terminating at its inner end in a ring which is coaxial of the branches, a single inner conductor element passing through and slidable in said ring, a stationary inner conductor in each branch, with its inner end terminating at a spacing from the common inner conductor approximating the length of the slidable element, whereby theA latter may be used to connect said common inner conductor to one or the other of the branchinner conductors, a gear rack connected to said slidable element,

,a very small diameter gear meshing with said rack, a

handle manually rotatable for about one-half revolution to point in the direction of one branch or the other, a large diameter gear turned by said handle, a pinion meshing with said gear and driving the aforesaid rack gear, the step-up gear ratio being such that the slidable element is `moved all the way to one or the other branch inner conductor by a half turn of the handle and the handle acts as l an indicator of the switch position.

6. A coaxial switch comprising aT-shaped housing providing the hollow outer conductors of astem and two aligned branches, a common inner conductor through the stem terminating at its inner end in a ring which is coaxial oi the branches, lan inner conductor element passing through and slidable in said ring, a stationary inner conductorin each branch, with its inner end terminating at a spacing from the common inner conductor approximating the length of the slidable element, whereby the latter may be used vto connect said common inner conductor to one or the other of the branch inner conductors, said slidable element being a hollow cylinder made of resilient conductive material, the end portions 'of said cylinder being longitudinally slotted with a large number of relatively long slats to make the same resiliently yieldable, the inner ends of the branch inner conductors terminating in cylindrical seats, said seats and the aforesaid cylindrical ring at the inner end of the common conductor being dimensioned to slidably receive the slottedl end portions of the slidable element with a snug tit for good electrical contact. I

7, A coaxial providing the hollow outer conductors of a stem and two aligned branches, va common inner conductor through the stem terminating at its inner end in a ring which iscoaxial of the branches, an inner conductor element passing through and slidable in said ring, a stationary inner conductor in each branch, with its innerfend terminating fat a spacing from the common inner conductor approximating the length of the slidable element, whereby the portion,v said end portions being longitudinally slotted with a large number of relatively long slots to make the same'resiliently yieldablethe inner ends ofthe branch l inner conductors terminating incylindrical seats, said seats and the aforesaid cylindrical ring at the inner end lof the common conductor being dimensioned lto slidably receive the slotted ends of the slidable element'with a snug t for good electrical contact 'i 8. A coaxial switch comprising a T-shaped housing providing the hollow outer conductors of a stem and two aligned branches, a common inner conductor through the stem terminating at its inner end in a ring which is coaxial of the branches, an inner conductor element passing through and slidable in said ring, a stationary inner conductor in each branch, with its inner end terminating at a spacing from the common inner conductor approximating the length of the slidable element, whereby the latter may be used 'to connect said common inner conductor to one or the other of the branch inner conductors, said slidable element being a hollow cylinder made of heat treated beryllium copper, the end portions of said cylinder being slightly greater in diameter than the mid portion, said end portions being longitudinally slotted with a large number of relatively long slats to make the same resiliently yieldable, the slots being long enough to pass through a part of the reduced diameter mid portion to increase the yieldability of the end portions, the inner ends of the branch inner conductors terminating in hollow cylindrical seats, said seats and the aforesaid cylindrical ring at the inner end of the common conductor being dimensioned to slidably receive the slotted ends of the slidable element with a snug lit for good electrical contact.

9. A coaxial switch comprising a T-shaped housing providing the hollow outer conductors of a stem and two aligned branches, av common inner conductor through the stern terminating at its inner end in a ring which is coaxial of the branches, an inner conductor element passing through and slidable in said ring, a stationary inner conductor in each branch, with its inner end terminating at a spacing from the common inner conductor approximating the length ofthe slidable element, whereby the latter may be used .to connect said common inner conductor to one or the other of the branch inner conductors,

an insulation rod extending through said aligned inner conductors and slidable element, said rod being secured to said element but being slidable in said stationary branch inner conductors, means operatively connected to said rod to slide said rod longitudinally, said slidable element being a hollow cylinder made of resilient conductive t material, the end portions of said cylinder being longituelement with a snug t for good electrical contact.

switchicormprising a T-shaped housing branch, with its inner end terminating at a spacing from the common inner conductor approximating the length of the slidable element, whereby the latter may be used to connect said common inner conductor to one or the other of the branch inner conductors, meanstat the end of the stemfor connection toga coaxial conductor aligned with said stem, aligned means at the ends of the branches for connection to coaxial conductors aligned with one another and with the branches, an insulation rod which is shorter than the combined length of the branches extendslidable in said stationary branch inner-conductors, a part y of said rod having gear teeth to form a rack, a gear housed in one of the branches and meshing with said rack, means passing through the. side of said branch to rotate said gear, said slidable element being a hollow cylinder made of resilient conductive material, the end portions of said cylinder being longitudinally slotted with a large number of relatively long slots to make the same resiliently yieldable, the inner ends of the branch inner conductors terminating in cylindrical seats, said seats and the aforesaid cylindrical ring at the inner end of the cornmon conductor being dimensioned to slidably receive the slotted end portions of the slidable element With a snug t for good electrical contact.

11. A coaxial switch comprising a T-shaped housing providing the hollow outer conductors of a stern and two aligned branches, a common inner conductor through the stern terminating at its inner end in a ring which is coaxial of the branches, an inner conductor element passing through and slidable in said ring, a stationary inner conductor in each branch, with its inner end terminating at a spacing from the common inner conductor approximating the length of the slidable element, whereby the latter may be used to connect said common inner conductor to one or the other of the branch inner conductors, an insulation rod extending through said aligned inner conductors and slidable element, said rod being secured to said element but being slidable in said stationary branch inner conductors, a part of said rod having gear teeth to form a rack, a small diameter gear housed in one of the branchinner conductors and meshing with said rack, said inner conductor being cylindrical and said gear being so small in diameter that it does not project outside the cylindrical surface of said inner conductor, an insulation shaft extending from said gear to a point outside the housing, a rotatable handle, and means gearing said handle to the aforesaid insulation shaft, said slidable element being a hollow cylinder made of resilient conductive material, the end portions of said cylinder being longitudinally slotted to make the same resiliently yieldable, the inner ends of the branch inner conductors terminating in cylindrical seats, said seats and the aforesaid cylindrical ring at the inner end of the common conductor being dimensioned to slidably receive the slotted element with a snug t for good electrical contact.

l2. A coaxial switch comprising a T-shaped housing providing the hollow outer conductors of a stem and two aligned branches, a common inner conductor through the stem terminating at its inner end in a ring which is coaxial of the branches, an inner conductor element passing through and slidable in said ring, a stationary inner conductor in each branch, with its inner end terminating at a spacing from the common inner conductor approximating the length of the slidable element, whereby the latter may be used to connect said common inner conductor to one or the other of the branch inner conductors, an insulation rod extending through said aligned inner conductors and slidable element, said rod being secured to said element but being slidable in said stationary branch inner conductors, a part of said rod having gear teeth to form a rack, a small diameter gear housed in one of the branch inner conductors and meshing with said rack, said inner conductor being cylindrical and said gear being so small in diameter that it does not project outside the cylindrical surface of said inner conductor, an insulation shaft extending from said gear to a point outside the housing, a handle manually rotatable for about one-half revolution to point in the direct-ion of one branch or the other, a gear turned bysaid handle, a pinion meshing with said gear and driving the aforesaid insulation shaft, the step-up gear ratio being such that the slidable element is moved all the Way to one or the other branch inner conductor by a half turn of the handle, said slidable element being a hollow cylinder made of resilient conduc tive material, the end portions of said cylinder being longitudinally slotted to make the same resiliently yieldable, the inner ends of the branch inner conductors terminating in cylindrical seats, said seats and the aforesaid cylindrical ring at the inner end of the common conductor being dimensioned to slidably` receive the slotted element with a snug lit for good electrical contact.

13. A coaxial switch as defined in claim 2 in which the means extending outward from the rack gear is an insulation shaft which has ilats at both ends, the ats at one end being perpendicular to the iiats at the other end, said flats being received between mating flats and thereby serving to transmit driving torque to the shaftand from the shaft to the rack gear, said ats functioning somewhat as universal joints.

14. A coaxial switch as dened in claim 3 in which the insulation shaft extending outward from the rack gear has flats at both ends, the ats at one end being perpendicular to the tlats at the other end, said flats being received between mating flats and thereby serving to transmit driving torque to the shaft and from the shaft to the rack gear, said ats functioning somewhat as universal joints at the ends of said insulation shaft and thereby accommodating any slight misalignment of the shaft.

15. A coaxial switch as delined in claim 4 in which the insulation shaft extending outward from the rack gear has iiats at both ends, the flats at one end being perpendicular to the flats at the other end, said flats being received be tween mating ats and thereby serving to transmit driving torque to the shaft and from the shaft to the rack gear.

16. A coaxial switch as deiined in claim 10 in which the means extending outward from the rack gearVV is an insulation shaft which has Hats at both ends, the flats at one end being perpendicular to the flats at the other end,

said flats being received between mating ats and thereby serving to transmit driving torque to the shaft and from thershaft to the rack gear.

17. A coaxial switch as dened in claim 11 in which the insulation shaft extending outward from the rack gear has ats at both ends, the ats at one end being perpendicular to the llats at the other end, said flats being received between mating flats and thereby serving to transmit driving torque to the shaft and from the shaft to the rack gear, said flats functioning somewhat as universal joints at the ends of said insulation shaft and thereby accommodating any slight misalignment of the shaft.

18. A coaxial switch as deiined in claim 12 in which the insulation shaft extending outward from the rack gear has Hats at both ends, the iiats at one end being perpendicular to the iiats at the other end, said flats being received between mating flats and thereby serving to transmit driving torque to the shaft and from the shaft to the rack gear.

References Cited in the file of this patent UNITED STATES PATENTS 2,637,787 Price May 5, 1953 2,794,087 Jennings et al. May 28, 1957 2,949,586 Holzschuh et al. Aug. 16, 1960

Claims (1)

1. A COAXIAL SWITCH COMPRISING A T-SHAPED HOUSING PROVIDING THE HOLLOW OUTER CONDUCTORS OF A STEM AND TWO ALIGNED BRANCHES, A COMMON INNER CONDUCTOR THROUGH THE STEM TERMINATING AT ITS INNER END IN A RING WHICH IS COAXIAL OF THE BRANCHES, AN INNER CONDUCTOR ELEMENT PASSING THROUGH AND SLIDABLE IN SAID RING ON THE COMMON AXIS OF SAID BRANCHES, A STATIONARY INNER CONDUCTOR IN EACH BRANCH, WITH ITS INNER END TERMINATING AT A SPACING FROM THE COMMON INNER CONDUCTOR APPROXIMATING THE LENGTH OF THE SLIDABLE ELEMENT, WHEREBY THE LATTER MAY BE USED TO CONNECT SAID COMMON INNER CONDUCTOR TO ONE OR THE OTHER OF THE BRANCH INNER CONDUCTORS, MEANS AT THE END OF THE STEM FOR CONNECTION TO A COAXIAL CONDUCTOR ALIGNED WITH SAID STEM, ALIGNED MEANS AT THE ENDS OF THE BRANCHES FOR CONNECTION TO COAXIAL CONDUCTORS ALIGNED WITH ONE ANOTHER AND WITH THE BRANCHES, AN INSULATION ROD WHICH IS SHORTER THAN THE COMBINED LENGTH OF THE BRANCHES EXTENDING THROUGH BOTH OF SAID ALIGNED INNER CONDUCTORS AND THROUGH SAID SLIDABLE ELEMENT, SAID ROD BEING SECURED TO SAID ELEMENT BUT BEING SLIDABLE IN BOTH OF SAID STATIONARY BRANCH INNER CONDUCTORS, AND MEANS MOUNTED ON THE SIDE OF ONE OF THE BRANCHES OPERATIVELY CONNECTED TO SAID ROD TO SLIDE SAID ROD LONGITUDINALLY.

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