US2568050A - Rotary selective switch - Google Patents

Description

Sept. 18, 1951 E. A. BRYAN 2,568,050

ROTARYv SELECTIVE SWITCH Filed Aug. 6, 1947 2 Sheets-Sheet 1 INVENTOR. Ernest Alfred Bryan Sept. 18, 1951 E. A. BRYAN 2,568,050

ROTARY SELECTIVE SWITCH Filed Aug. 6, 1947 2 Sheets-Sheet 2 INVEN TOR. Ernesf Alfred Bryan Attorney Patented Sept. 18, 1951 ROTARY SELECTIVE swi'rcH' Ernest Alfred Bryan, Bexley, Englaiid, as'signor' to Siemens Brothers & Company Limited, Lon= don, England, a British company Application August 6, 1947, Serial No. 766,793

In Great Britain April 5, 1946 Section 1, Public Law 690, August 8,1946 Patent expires April 5, 1966 3 Claims.

number of rows of contacts in a bank the production of such a moulded bank would be satisfactory but when switches containing different numbers of rows of contacts are required such proposals are uneconomical, resulting in either the provision of a larger moulding with more contacts than those required or the provision of anumber of moulds of different sizes. Besides the wasteful bank that may be produced, corresponding wipers would be required, or at least the wiper shaft would need to be such as to accommodate a variable number of wipers.

' Moreover, in the case of a built up bank and assembly of wipers difliculties arise in ensuring the accurate spacing of the several rows of contacts and the co-operating wipers, and the present invention seeks to overcome these difiiculties. According to one feature of the invention a switch bank is built up from a number of moulded units, as many units being assembled together to provide the required number of rows, or levels as -they are sometimes called, of contacts.

Ideally, a unit would comprise a single row of mouldedin contacts but in practice such a unit would suffer disadvantages owing to its thinness and it is preferable to mould two or even three rows of contacts unto a unit. In order that each unit may be accurately adjusted for thickness so that the spacing between adjacent rows of contacts in assembled units is precisely the same, having E regard to manufacturing tolerances, each unit is provided with bosses on at least one of its major surfaces and these bosses may be machined to provide the adjustment necessary. The bosses are preferably situated so that the clamping bolts *pass through them. i

- The unit besides containing the fixed or outlet contacts may include feeder springs for making connection to the wipers to be assembled in contact relationship with the moulded-in fixed contacts. in an arcuate bank the feeder springs may be accommodated at one end of the moulded unit, conveniently in a plane between two levels of fixed contacts in the unit. In another arrangement the moulded-in contacts of a level may be of two kinds, a contact of each kind being adapted to be bridged by a multi-armed wiper in any position in the bank. The contacts of one kindmay be the so -called fixed contacts and the contacts of the other kind may be feeder contacts and. these latter may be formed as strips suitably disposed in the bank.

According to another feature of the invention the wipers are assembled as units, there being as many wipers in a unit as there are rowsof contacts in a bank unit with a spacingcorresponding to that of the contact rows. Each" unit is provided with surfaceswhereby the overall axial length may be adjusted. The wipers form-- ing a unit may be assembled on a metal tube and are spaced apart to correspond with the spacing of'the contact rows of a bank unit and insulated from one another and from the tube,

a number of units being clamped togetherto form a complete wiper assembly whichis mounted on the wiper shaft. By this means the individual wipers may be adjusted for pressure and aligmnent before assembly on the shafts. final setting being given on fitting the wiper shaft to the switch bank.

The wiper assembly and the driving mechanism may be separately assembled so that the wiper shaft may be removed without its being attached to the relatively heavy driving mechanism. f

An arcuate contact bank and wiper assembly embodyingthe invention is illustrated by way 'of example in'the accompanying drawings,* In

'wiper assembly corresponding to the view of the bank units showninFig. 3.

The bank units and their assembly will first be described with reference to Figs. 1, 2 and 3. The bank unit illustrated consists of two levels of contacts 2 moulded into a block I of synthetic resin or other suitable thermo-setting plastic Substance. In some cases it may be convenient to mould more than two levels into a unit. The block I has bosses 3 formed on its two major surfaces, three such bosses on each surface are shown, and these may be machined, if necessary, to determine the exact overall thickness of the unit. The bosses and the portion of the block lying beneath them have holes through them to accommodate the clamping bolts 6. Inthe unit illustrated a level consists of a number of fixed contacts 2 and at each end of the level a strip 4 serving as feeder contacts. The arcuate length of the strips 4 will be equal to that of half the number of contacts 2 so that a pair of electrically connected wiper arms will make contact, one with a feeder strip 4 and the other with a fixed contact 2 in any position in the bank. The

tag ends of the contacts and strips to. which the connecting wires are soldered are designated 5. The several units are assembled on clamping bolts 6 which pass through the bosses 3 and the assembled units are-brought into contact with one another through'the bosses and clamped between end plates 1 by means of nuts 8 on the bolts 6, A bank built up'by this means may consist ofa number of like units or units comprising different numbers oflevels, according to the number of levels required in the switch. A greater measure of standardisation may be had by forming all units alike which leadsto simplification indetermining the overall .dimensions of the, individual units and'requires only one size of mould.

Reference will now be had to Figs. 4, 5 and b which show a wiper unit and the manner of assembly. The wiper unit shown is adapted to be used with two-level bank units having co -planar iinedfcontacts and, feeder strips as illustrated in Fig. land comprisestwo four-armed Wipers of the shown in plan in Fig. 4. 'A wiper consists of a central part Sin which is a central hole for mgunting them on a carrier, with four arms H1 at right, angles to. one another, the arms turning from the central part through a right angle at the elbow ll leaving a slot. l2 between the arm and the central part, Theslfot I2 and the shape and position of the hole I3 assist in giving the arm the desired flexibility, Each arm. has attached to it by; eyelets M a tipmember [5 the. tip of which is suitably shaped for rubbing on the band contacts. There are actually two tipmember's ISsecured one on each side of the end of the arm and the tips of these members are adapted to rub one on @391 side of the contacts, of a level, Two wipers with i la ns as s 6 neach sideoi e at their centre are spaced apart bymember II, the spacing corresponding to the spacing of twolevels in a bank unit, the wipers and spacing-member being passedo-v'er an insulating tube 18' and as.- sembled on a metal carrier. tube |9. f Further members. are positionedon the. outside of the insulated wipers, over the insulating Washers l6 andlsurrounding the tubes l8 and It, the member 20 being formed withrecessesto accommodate the, tube l8. and the ends being recessed toaccomm e'm tal Oi th e 9 hat w ll be isn n ve f ompl ti-ng the. as mbly-j The overall axial length'of the unit may be adjusted, if ne ssa b ma n n be' l aceso y a ui able compressing operation of the two members 20,

4 so that the distance between opposite faces of the members will correspond with the thickness of a bank unit over the bosses 3.

The wipers 9 and their tip members I5 may be of different materials and of diiierent thicknesses whereby a still centre part and more resilient tips may be had. In fitting the tip members to the wiper arms they are first tack welded to position them after which the eyelet holes are punched and the eyelets inserted and riveted over. The alignment and pressures of the tip members may be adjusted apart from the complete assembly on the wiper spindle. In assembling the wipers as a unit, they and the spacing and other insulating members are assembled on the carrier tube l9 and while the unit is held under pressure the ends of the tube are spun over to enter the recesses in the member 20, the metal of the tube lying below the surface of the members 29. The required number of units are assembled on the wiper spindle 2i, the assembly being shown loose in Fig. 6, and after the units have been brought into contact with one another nuts are threaded on the threaded end or ends of the spindle to clamp all the units together. The clamping nuts bear on the members. 28. and not on the carriertubes; IS, the ends of which, as; before mentionedtlie below the surfaces of the members 25;, After assembly on the spindle and the insertion of the spind-le in position relative to the contactbank any final i m ntpf e tipsto agree with the bank-pen,- tacts is readily made by slightly setting theelbows ll upor down. v 3

Iclaim: 1

1. For use in a selecting switch, a wiper as: sembly consisting of a plurality of wipers mounted in spacedrelation, a plurality of, arcuate moulded contact units, each. unit having aseries of con:- tacts for cooperation with one, of said wipers, al spacing bosses on at least o e f; the surfaces of each of said units, and shaft means for clamping said units together in such a manner that h spa ng w n a ja en iand therefore the alignment of said contacts with said wipers isdetermined by the size ofthe bosses on said units.

2-. For use in a selecting switch, a plurality of arcuatemounlded contactunits, each of said'units having a series of contacts, a wiper assembly com;- prising a shaft and aplurality of wipe-rassembly units mounted on said shaft, and spaced for co;- operative relationship with said series of contacts, each one of said wiper assembly units comprising wipers mounted between tubular insulators having circular recesses in the, ends thereof, and a metal tube projecting. axially through said wipers and said tubular insulators, saidmetal tube ha in its ends: n n ai r esses oi; said tubular insulators so that said metal tube. does o p ojec r i ub a ns l or-sereby causing no interference with the spacing between said wiper assembly units and thereforev the cooperation thereof with said series of contacts. 3. For use inaselectingswitch rhaving a plurality ofwiper assembly units mounted; adjacently n a shaft, a pe sem ly ni q pr ine a plurality of wipers mounted between a plurality of annular insulators, the-first and last insulator having circular recessesin the ends thereof, and a, metal tube p jec n axia ly through. sai wipers and said insulators and; having, its ends pun. into a e e ses; of sa d. in ulatorsrther by r gidly ma tain n s id, ss mbly nit t gethe ith u pr ec ing ey nd. th ends of saidaizst and last insulators, the ends of said insulators ERNEST ALFRED BRYAN.

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

UNITED STATES PATENTS Number Name Date Guttman May 1, 1906 Dixon Feb. 9, 1915 Number 6 Name I Date Richard Mar. 24, 1925 Harrison Oct. 15, 1929 Sengebusch Dec. 3, 1929 Erickson Mar. 3, 1931 Schreiber Oct. 18, 1932 Muller Apr. 10, 1934 Erickson Aug. 28, 1934 Wagner Oct. 20, 1936 Drake Oct. 14, 1941 Drake May 4, 1943 Graham Mar. 26, 1946

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