US2575806A - Contact bank for 25-point 10-wiper rotary switches - Google Patents

Description

Nov. 20, 1951 K. w. GRAYBILL ETAL 2,575,306

CONTACT BANK F 25-POINT lO-WIPERROT swnrcn Filed Feb. 16, 1950 2 SHEETSSHEET 1 INVENTORS. KENNETH W. GRAYBILL BY HANS SENGEBUSCH ATTORN EY N 1951 K. w. GRAYBILL ETAL 2,575,806

. CONTACT BANK FOR ZS-POINT lO-WIPER ROTARY SWITCH Filed Feb. 16, 1950 2 SHEETS-SHEET 2 v INVENTORS. KENNETH W. GRAYBILL HANS SENGEBUSCH ATTORNEY Patented Nov. 20, 1951 CONTACT BANK FOR 25-POINT IO-WIPER ROTARY SWITCHES Kenneth W. Graybill, Elmhurst, and Hans Sengebusch, Villa Park, 111., assignors to Automatic Electric Laboratories, Inc., Chicago, 111., a corporation of Delaware Application February 16, 1950, Serial No. 144,521

17 Claims.

This invention relates to switch banks in general and more particularly to switchbanks for one or two motion switches.

An object of this invention is to provide a contact bank for a one or two motion switch which comprises cheaply fabricated parts, easily assembled and yet accurate and efficient in operation.

In keeping with thi object, a feature of the invention is the novel construction of the insulator elements which when assembled into a completed contact bank hold the metallic contacts stationary and prevent all lateral and longitudinal movement thereof.

Another feature of this invention is the provision for slightly bowed contacts further restricting the possibility of longitudinal contact slippage.

A further feature of the invention resides in the degree of compressibility afforded by the insulators.

Still another feature of the invention lies in provision for maintaining close tolerances in both overall dimension and the distances between the various levels of contacts.

These'and other features will be pointed out in the ensuing specification and appended claims, reference being had to the accompanying drawings in which:

Fig. 1 is a plan view of an insulator element of the contact bank.

Fig. 2 is a cross section of the insulator element along line AA in Fig. 1.

Fig. 3 is a cross section of the insulator element along line BB in Fig. 1.

Fig. 4 is a cross section of the insulator element along line CO in Fig. 1.

Fig. 5 is a partial plan view of two contact strips as they would be arranged with relation to the insulator element adjacent a perforation for the compressing means.

Fig. 6 is a partial front view showing a pileup of insulator elements, contact strips, clamping plate and compression means.

Fig. 7 is a cross sectional view of a pileup along line DD in Fig. 5 and evidences a stack of insulator elements, contact strips, clamping plates and compression means and particularly depicts the bowed contact strip.

Contact banks for one or two motion switches have generally been made by clamping together a pileup of insulators with a plurality of metal contact strips spaced apart therebetween. The

insulators were generally flat, solid and substantially incompressible, necessitating very close production tolerances in order to have the distance between rows of contacts and overall dimensions of the bank meet operating requirements. But an even greater trouble factor exists in conventional contact banks, namely slippage of the contacts from their original placed positions, and such slippage is e1ther lateral, longitudinal or both.

The inventors have in thi invention provided. a molded, shaped insulator element. Because of relatively small area raised edges on the insulators, there is a sufficient degree of compressibility to facilitate maintaining close tolerances for both overall dimensions of the contact bank assembly as well as distances between the various levels of contacts therein.

The invention further provides in the form of the insulators means to slightly bow the contact strips upon compression of the bank assembly as well as seats and shoulders for the contact strips to engage so as to eliminate all possibility of slippage, either laterally or longitudinally. A notch in the contact itself to engage an insulator shoulder lends itself even further to this end.

Having generally described our invention, now, with reference to figures and numbered components we shall describe the invention in greater detail.

Referring again to the structure illustrated in Figs. 1-7 inclusive, the contact bank consists of metallic contact strips l, molded insulator elements 2, clamping plate 3 and compression means 4.

The insulator elements 2 are molded so that all edges, upper and lower will be raised. The upper raised edges right and left will themselves alternately have shoulders 5 and depressions 6. The lower raised edges right and left likewise alternately have elongations l and recesses 8. Shoulders '5 will all be immediately above lower recesses 8 and lower elongations i will all be immediately below depressions 6. All shoulders 5, right and left are in line longitudinally and similarly all depressions right and left, lower elongations right and left and recesses right and left. will be longitudinally aligned respectively. Upper depressions S are of a depth equal to the sum of the thickness of a contact strip l plus the depth of a lower elongation l. The upper shoulders 5 are in height equal to the depth of adjacent depressions 6, and likewise, lower elongation I are equal in length to the length of adjoining recesses 8. Longitudinally betweencorresponding pairs of lower elongations I, right and left, is a semi-cylindrical appendage 9 which will be slightly greater in height than one elongation of its aligned pair of lower elongations, substantially equal to the other and equal in width to both. As shown in Fig. '7, the semi-cylindrical appendage 9 cooperates with the depressions 6 and elongations jl to causecontact strip l to-bow beneath the appendage 9. Right depression His-"lower than left depression 6 for the purpose of produc ing nearly all of the displacement caused by the bowing of strip l at the terminal end. of, contact strip I, while the contact end'of the striprernains substantially horizontal. As shown further in Fig. 7, and also in Figs. 2, 3 and 4, right elonga-' tion 1 is longer than left elongation F, for the purpose of fitting into the corresponding depres sions 6 to give a firm interlocking relationship between adjacent supports and maintain the proper bow in the contact strips. Longitudinally between corresponding pairs of upper shoulders right andfileft, are raised rings lilintegral with the insulator element's, and Which are reinforcem ts forperforations or bores l l extending thru s raised rings I8- and the insulator elements. T esebor'es orperforations are for accepting suitablecompression means when a group of such like insulator elements are stacked ina pileup.

' These insulator elementsmay be molded from any plastic or synthetic resin material such as a phenolcondensate product and in a particular The dye alPsha-peof the insulator element will depe upon the type switch to which it is to be adapted; For standard Strowger type switch rotary switch banks, the plan shape may be a semi-circular one as shown in Fig. 1,

with pairs of corresponding components such as upper-depressions fore and aft arranged radially eon: However, the inventors do not wish to lim their invention to a semi-circular bank as it;is equally adaptable to a rectangular type arrangement" with the depressions fore and aft suitablegeometric form.

C lonta'ctfstrips'l are then laid longitudinally equally spaced apart; or' for that matter, to any in 'aligned; pairs of upper edgedepressions 6.

The cfo aetjstrips' may'be'cut' or stamped from "any" suitable conducting material, preferably brass or Rhosphorbronze. The strips as "shown injFig Sli a e anjoVeralI wedgeshape for use in aj' spaced apart" arrangement. Their oful d" justas readily'be rectangular for use in a"parallel' spaced apart arrangement.

This seating in depressions 5, assumes a fixed positi "forfthe contact's'withoutlateral move- Alo'ngorie lateral edge of each 'strip 'l'is cut an obtuse isoscel'es angle l2 whose vertex e" at the center 'point' both laterally; and lon tudinally'of the strip; Thisl'arg'e angular "positioned so that the contact may circumvent the compression means passing mm b'or bodiment in Fig. 5. Notch [2' may be forward or' rearward' of the angular cut previously described as the circumstances warrant. Fig. 5

with the exception that lower appendages fi are 55. compressibility of the" relatively small" area depressions andff protrud 3 shows one embodiment with notch 13 rearward of cut l2. This notch 13 engages a shoulder 5 and thereby prevents longitudinal movement of the contact strip. A further purpose of notch I3 is that when it is cut at a predetermined position, it will. insure; the uniform protruding length of' all contacts in the "bank. Forward ends I4 and rearward ends I5 of contact strips I protrude beyond the bank in well known manner, and. said, ends are not of unfamiliar design i'nthelart.

'Toform now a contact bank or pileup, it is only. necessary topile up a predetermined number 'of insulajtQr elements 2 equipped with contact, strips l as hereinbefore described, one upon another until the desired number of rows is reached; The.v uppermost insulator element It is then added but without contact strips in its.

upper depressions. At, this stage, all lower elongations l neatly dovetail into upper depressions 6; with appendages 9 lightly resting centrally or perforations aligned with those in the insulator elements.

' The bottom of this pileup is then fitted into a bottom insulator element [1, shown in Fig. 7, which for all practical purposes is identical to the insulatorelements 2 described hereinbefore not present, and the lower raised edges maybe ionge'r; In the embodiment shownin Fig; '7, bottom insulator Il is shown to have somewhat longer-lower edges [8.

Beneath the-bottom insulator II- is placed-another clamping member 3"described her'eihbefore.

- Application of compression means 4; willnow complete theflbank. All elongations T dovetail tightly into depressions 6, snugly hoIding 'contact strips I while appendages 'Q'being slightly greater in" depth than 'th'e lower elongations' 'l press down centrally on allcontact strips-"eats ing them to flex or bow'slightly. I

In this position the contact bank: is complete.

' Notches" l3 co-ioperatihg wi-th shoulders? along with the bows in 'thecontac't strips"; due tofthe action of the compression means i -and appendag'e's- 9 upon strips" I hold strips-l fixed and' without longitudinal motion while; the se ting; arrangement provided fonthejcontact s'tr'ip's'j I by depression 6 willhold saidstrips free froin lateral mbtiofi. 1 z An additional factor to be notedis thesli'ght raised edges of insulator elements 2; which allow for mai taining. close; tolerances bo thf for 'overall d n ion ii zbont t nki 's, w distances between the varioq levelsfor- Ha i des r b d t ,7 n f io i' 31 What we claimand desi e to" be; protectedby: is 'uance of Letters Patent'of th'e UnitedStatesisi 1. In a switch bank a plulifalityiofnioldeiinsulato'r elements o upon anojth 'ergrais' d-"'ed ges on said insulator elements, "upp. llf raised eidgs t. n e y sal em av. he ldr i i depressions respectively alj ned nf pa rs; lower raisededges right and left having alternately elongations' and 'I recessions respe uy ly; aligned in pairs, 's'aid' elong' atifolns in'irned iately below depressions; contact s ipsJaying ins'ai '"th'erebeyon l n itior'is Fw li i ei li l anexticswer'insuiatcreiemefitandsaiurecessitns on said lower raised edges receiving said shoulders of said next lower supports, and means to com- .press said elements, said shoulders, depressions,

recessions, elongations and raised edges being so constructed as to hold said contact strips firmly in place and said insulators together under the compression of said means.

2. In a switch bank as claimed in claim 1,

semi-cylindrical appendages longitudinally between said lower edge elongations, the depth of said appendages being slightly greater than one of said elongations and substantially equal to the other, said appendages co-operating with said means to bow said contact strips immediately thereunder upon application of said means.

3. In a switch bank as claimed in claim 1, said insulator elements having a plurality of aligned perforations between said contact strips, said perforations to accept said compression means.

4. In a switch bank substantially as claimed in claim 1, said insulator strips comprising a molded synthetic resin.

, 5. In a switch bank substantially as claimed in claim 1, said insulator strips comprising molded polymerized ethylene.

6. In a switch bank, a plurality of contact strips, a plurality of semi-circular insulator ele- ,ments, raised edges on said insulator elements,

each of said insulator elements comprising a plurality of radially equal integral components; every other radial component having its lower edges elongated fore and aft and a semi-cylindrical appendage longitudinally therebetween of slightly greater depth than on of said elongated lower edges and substantially equal to the other, While the upper edges right and left immediately thereabove are depressed, the depth of said depression being the thickness of a contact strip plus the depth of a lower edge elongation; and therebetween every other radial component having shouldered upper edges right and left and recessed lower edges right and left; a contact strip laying in each pair of upper depressions right and left and projecting thereloeyond, in-

sulator elements so equipped with contact strips stacked one above another in a pileup, elongated edges fitting into depressions; and compression means to hold said strips and insulator elements together, said depressions and said compression means co-operating with said semi-cylindrical appendages and raised edges to cause a bow in said contact strips and fixedly hold them in place.

7. In a switch bank as claimed in claim 6, said bowed contact strips comprising equal lengths of metal, one lateral edge thereof having two indentations, one indentation being obtusely angular in shape, the vertex of which is the longitudinal and lateral center point of said contact strip, the other indentation being a rectangular notch rearward of said first indentation, said one indentation functioning to circumvent said compression means, said other notchlike indentation engaging an upper aft raised edge portion co-operating with said compression means to fixedly hold said contact strips in place.

8. In a switch bank, a plurality of bowed contact strips, a plurality of molded semi-circular insulator elements, raised edges on said insulator elements, the upper right and left raised edges of said insulator elements having alternate depressions and shoulders therein, said bowed contact strips laying in corresponding pairs of depressions right and left, and the lower right and left raised edges of said insulator elements alternately elongated and recessed, elongations of lower edges immediately beneath depressions in upper edges, and longitudinally between said lower edge elongations semi-cylindrical appendages slightly greater in depth than one of said lower edge elongations and substantially equal to the other; a predetermined number of such insulator elements with contact strips stacked one upon another in a pileup, lower edge elongations of the next higher fitting into upper edge depressions of the next lower, the uppermost insulator element being deprived of said contact strips, semicircular clamping plates above and below said pileup, and compression means to vertically compress said pileup, said means co-operating with said semi-cylindrical appendages resting centrally on the next lower contact strip, and further co-operating with the dovetailing of said elongations into corresponding depressions so as to cause said contact strips to bow and said elongations and depressions to mesh holding all constituents fixedly in place.

9. In a switch bank, a plurality of insulator supports arranged in layers, a plurality of contact strips in spaced apart relationship between said layers, compression means in said bank to vertically compress said layers, and means integral with said insulator supports for causing said strips to deflect upon application of said compression means to cooperate with said supports to rigidly fix said strips in position in said bank.

10. In a switch bank, a plurality of semicircular insulator supports arranged in layers, a plurality of contact strips in a radial spaced apart relationship between said layers, compression means in said bank to vertically compress said layers, and means integral with said insulator supports for causing said strips to deflect upon application of said-compression means to cooperate with said supports to rigidly fix said strips in position in said bank.

11. In a switch bank, a plurality of insulator supports arranged one upon the other having apertures therein, a plurality of fiat contact strips arranged in a spaced apart relationship between each of said insulator supports and projecting transversely through said supports through said apertures, compression means in said bank for vertically compressing said supports one upon the other to hold said strips in said apertures, and means integral with said support for causing said strips to bow upon application of said compression means.

12. In a switch bank, a plurality of formed insulator supports, having projections and recesses thereon, arranged in a stratified manner, the projections of one of said supports partly engaging corresponding recesses in a support in the next stratum, contact strips passing transversely through said recesses in said supports and extending therebeyond, central projections in said supports transversely aligned with the recesses in the support in said next stratum, and compression means in said bank for vertically compressing said stratified arrangement to cause said central projections to deflect said strip and to cooperate with said partial engagement to fix position of said strip in said bank.

13. In a switch bank, a plurality of contact strips arranged in rows in a spaced apart relationship, insulator supports separating said rows, a plurality of downward projections on opposing sides of said supports transversely aligned, said supports also having a plurality of recesses on spac ous verse alignment with saiddownward projections and located therebetween, said central downward projections having adepth greaterthan one of said downward projectionsand substantially equal to the other, compression means to compress said supports vertically to cause said projections and recesses to firmly gripsaid: strips to prevent lateral movement; thereof, and: to cause said central: downward projections todeflect saidstrips to cooperate with said: projection and recesses to prevent longitudinal movement of saidstrips thereof.

I4. Ina switch bank, a plurality of insulator supports arranged: in layers, a plurality of contacts str-i-ps arranged in a-spaced apart relationship" between said layers, means integral with said supports for preventing lateral movement of said strips insaid support, means integral with said strips for interlockingwith said.- integral support means to prevent longitudinal movement or said strips in said support, compression means tovertically compress said layers, and, other means integral with said supports for causing saidstrips to deflect upon application of said compression means to further prevent longitudinal movement thereofl' 15; In a switchv bank, a plurality of insulator supports arranged in layers, a plurality ofcontact strips arranged in a spaced apart relationship-betweensaid layers, means integral with-said supports for preventing: lateral movement of said stripsbetween said layers; notches in said strips interlocking with said. means for preventinglongitudina-lmovement of said strips between said layers, compressionmeans to compress said layers vertically upon saidv strips, and other means integral. with said supports for bowing said strips uponapplication or said compression means to further prevent longitudinal movement thereof.

1 6'. In a'switch bank, a plurality of insulator supportsarranged inlayers, raised edgeson the uppensurtaces or said supports, depending edges on the lower surfaces of said supports; said edges having alternately-spaced shoulders, the shoulder of the upper edgeofiset' from the shoulderon the lower edge thereof, contact strips between said support layers, said contact strips resting between said raised edge shoulders and; overhanging said supports, said depending edge shoulderofa higher support also resting between said. raised edge shoulders of. the next lower support directly over said contact strips, compression means to vertically compress said. layers to retain said. strips fixed. between said shoulders, at central; depending: projection from said lower'surface, said central depending: projection bowing. said contact strip upon application of said compression means to further retain said: strips? between said shoulders;

17-. In a, switch. bank; a plurality; of insulator supports arranged layers,v raised: edges on; the upper surface of said supports, shoulders on! said raised edges, depending edges on the lower surfaceof said supports-, shoulders on. said depending edges said shoulders on said upper edges transversely aligned in pairs, said shoulders. on saidlower edges also aligned in pairs, said lower edge shoulders vertically" ofiset from said upper edge shoulders so that said; layers. of supports i-ntermesh, a plurality of: contact strips resting between; said upper edge shoulders and enclosed by saidintermeshing of. said layers, rectangular notches. in. said cont-act strips, said. notches engaging said raised edge shoulders to prevent longitudinal movement of; said strip: through said supports, a central depending projection on the lower surface of said: supports of greater length than one ofsaid: depending edge. shoulders and substantiallyequalto. the. other, central dependent projection. laterally offset from said depending edge shoulders, and compression. means for compressingisaid layers vertically, said depending. central: projection flexing said: contact strip. to further prevent longitudinal; movement thereof upon application of: said means.

KENNETH W. GRAYBZ'LL. HANS SENGEBUSCH.

EEFEF ENC S. siren,

The following references are ofrecord in the file of this patent:

UNITED STATES. PA'I'ENTS Number Name Date; 7

1,903,392 Triifany Nov; 14,.191 1 13499;137; Len'aghan Mar: r922 2; 4 5 7,! 703- Merkel Dec. 28, 1948

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