US2504027A - Multiple-contact switch - Google Patents

Description

April II, 1950 w. c. KUHLMAN MULTIPLE-CONTACT swrrcn Filed Oct. 25, 1946 ATTORNEYS Patented Apr. 1 1.1 950 UNITED STATES PATENT OFFICE MULTIPLE-CONTACT SWITCH William Carl Kuhlman, Cincinnati, hio,'assignor to The Kelley-Koett Manufacturing Company, 'Coving'ton, Ky., a corporation of Ohio Application October 23, 1946, Serial No. 705,156'

Claims. (Cl. 200 11) invention relates to electric switches of the multiple contact type.

One of the principal objects of the invention is to provide an electric switch for use in controlling a plurality of groups of circuits and which is of compact but rigid construction, readily produced from simple and easily manufactured component parts, and safe and positive in operation.

Another object is to provide a multiple-contact switch capable of controllinga plurality of groups of circuits each consisting of a plurality of separate circuits and which is of such construction that the number of groups of circuits and the number of circuits in any group or groups can be readily varied within a considerable range by simple re-arrangement of the switch parts.

A further object is to provide a multiple-contact switch wherein a single rotary switch arm plate can be used for the simultaneous, selective control of a plurality of groups of circuits and which is accordingly of compact construction and will occupy minimum space in use without sacrifice of safety or efiiciency.

It is also an object of the invention to provide a multiple-contact switch of the rotary type of such construction that the rotary switch arm can have floating movement axially between the stationary contact plates without effecting its electrical operation, thus permitting compara tively wide manufacturing tolerances and aifording-maximum ease and effectiveness in operation.

An additional object is to provide a multiplecontact rotary switch for controlling a plurality of groups of circuits which is provided with-simple and positive indexing mechanism constructed for ready adjustment to permit variation in the number of circuits in each group controlled by the switch or in the number of circuits in each such group.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawing and the appended claims.

In the drawing, in which like characters of reference designate like parts throughout- Fig. lie 2. viewin side elevation of a multiplecontact switch-constructed in accordance with the present invention;

:Fig. 2 is an elevational view of the same switch and taken at right angles to Fig. 1;

Fig. 3 is a view of the opposite side of the switch from that shown in Fig. 1 and with parts broken away to illustrate details of internal construction; Fig. 4 is a sectional view taken substantially on the line H of Fig. 1; and

Fig. 5 is a detail view in perspective illustrating one of the contact assemblies carried by the rotary switch arm plate.

In the drawing, which illustrates a preferred embodiment of the present invention, the two stationary contact plates l0 and H are shown as mounted in spaced and parallel relation, and the rotary switch arm plate, which is mounted between the contact plates, is designated generally by the reference character [2. The contact plates 10 and ll are shown as of identical construction and may be readily formed by molding from a suitable non-conducting plastic material such as a phenolic resin of the Bakelite type. Each of these contact plates is generally square in outline and has a large portion of its center removed to provide an annular shape. Legs l5 are formed on one side of each corner of these plates, and on its other side, each of plates l0 and H has a pair of shorter legs or lugs l5 formed at diagonally opposite corners.

While this construction, when the contact plates H] and II are assembled with the lugs 16 innermost and alternating, each lug will engage the adjacent fiat corner of the other contact plate and will thereby maintain the plates themselves in spaced and parallel relation as shown in Figs. 2 and 4. The switch also includes a pair of switch plates 20 and '2 I, shown as formed of metal, these switch plates being generally circular and considerably smaller than the contact plates l0 and II but each having four outwardly extending arms 22 adapted to register with the ends of the legs 15. Bolts and nuts 23 are passed axially through the legs [5 and lugs Hi and thereby hold. the contact plates and switch plates securely together as shown in 4.

A shaft 25 is journaled in switch plates 20 and 2| for rotation about an axis substantially normal to the switch plates and contact plates. As shown in Figs. 2-4, this shaft 25 includes a portion 26 lying between the switch plates which is rectangular in cross-section. A knob 21 or like control member for ready manipulation of the switch is indicated in Fig. 2 as secured to one end of shaft 25. The other end of the shaft carries the rotatable parts of the indexing mechanism, which is indicatedgenerally at 28 and is described in detail hereinafter.

Each of the contact plates in and H carries a multiplicity of contact members 30, shown as bolts and nuts for the ready attachment of wires, circumferentially arranged about the axis of shaft 25 and with their heads on the inner surfaces of the contact plates and each substantially directly,

opposite a contact on the other contact plate, providing opposed pairs of contacts as shown in Figs. 2 and 4. As shown in Fig. 3, the generally circular shape of the switch plates and 2| results in leaving exposed the nut ends of the contact members 30, thus facilitating wiring operations. In the switch shown in the drawing, there are twenty-four of these'co'ntact members 3|] on each of the two contact plates!!! and H.

The rotor 12 is a circular plate of Bakelite or like non-conducting material provided with a central aperture 33 which is square to receive the squared portion 26 of shaft 25, thus providing a simple arrangement for preventing relative rotation of the plate I2 and shaft while at the same time permitting relative axial movement of the rotor plate on the shaft. The rotor plate 12 carries one or more contact assemblies adapted to engage opposing pairs of stationary contactsasshaft 25 rotates and thereby to provide an electrical connection between these pairs of contacts. The drawing showsfour of these contact assemblies symmetrically disposed about the axis of the rotor plate. As shown, the plate I2 has a plurality of radially arranged slots 36 formed in its outer edge in'predetermined angular relation. Each contact assembly includes two arms 31' of resilient metal aligned with one of slots 36 and on opposite surfaces of the plate [2. Two bolts and nuts 38 serve both to secure each pair of arms 31 to the plate I2 and also to provide an electrical connection from one arm to the other. The outer end 40 of each arm 31 has its edges bent inwardly generally parallel of its length to give a somewhat rounded configuration, as best seen in Figs. 2 and 5, and these rounded side pieces of the arms extend into the slots 36.

With this construction as shaft 25 rotates, the contact assemblies will be brought successively into register with the pairs of opposed contacts 30, and since each pair of arms 31 is electrically connected together, these contact assemblies will thus provide a direct connection between the paired contacts 30 with which the arms 31 are in contact. The rounded formation of the ends and of the arms 3'! facilitates easy movement of the arms over the contactmembers, and these arms 31 and the plate [2 are of such thickness that the arms will be compressed axially into slots 36 when in register between a pair of contacts 30, as best seen in Fig. 4. This has the advantage of insuring adequate electrical contact and also of guiding the rotor plate [2 and maintainingit in proper position irrespective of its axial movement on shaft 25. In this way, the tolerances for formation of these parts are made quite wide, and also the assembly of the parts is greatly facilitated.

It will be seen that the number of groups of circuits which can be controlled by this switch, and hence the number of positions of the switch, is determined by the number of contact assemblies 35 carried by the rotor plate l2. With the four of these assemblies shown, each can engage six pairs of contacts 30 in 90 rotation of the rotor plate, but this number of positions of the switch can readily be changed by changing the number of contact assemblies on the rotor plate. For example, if two diagonally opposed contact assemblies are removed, the switch will be changed to a 12-position, 2-circuit switch. It can be changed equally readily to an 8-position, 3-circuit switch, by removing all the contact assemblies except the one shown in' section in Fig.

4 and replacing two of them at the slots 36 shown as empty in the drawing. It will also be seen that the arrangement of leads connected with contacts 30 may be varied as desired in accordance with the desired use of the switch. For example, some of the contacts 30 on one contact plate may be shorted to provide for selective connection of any of a group of the opposite contacts 30 into a single circuit, thus providing for a wide range of application for the switch by relatively simple rearrangement of its parts or of the connections thereto.

The invention provides indexing mechanism 28 adapted to insure accurate register of the contact assemblies 35 with contacts 30 and also to limit the number of pairs of each contacts 30 with which each contact assembly 35 can connect. As best shown in Figs. 1, 2 and 4, a platelike segment 24 is secured to shaft 25, as by means of a collar 46 and set screw, and has a series of notches 55 formed along one edge thereof and spaced angularly by substantially the same amount as adjacent contact members 30. An arm 41 is pivotally secured by a bolt 48 to the switch plate 25 and carries a roller 55 adapted to engage in the notches 45, a spring 51 being secured to the free end of this arm and to the switch plate as shown in Fig. l to urge the arm in the direction of plate 44 to cause this engagement of the roller in notches 45. The roller 50 is shown as comprising a roller bearing for maximum freedom from friction, and arm 4'! is pressed in to provide a dimple or lug 52 adapted to limit frictional contact between the inner surface of arm 41 and the outer surface of the switch plate. The adjacent outer edge of the switch plate is struck up at 53 to provide a stop limiting outward movement of arm 4'].

It will accordingly be seen that as shaft 25 is rotated, the arm 41 and its associated parts will act as a pawl and the roller 50 will engage successively in the different notches 45 in segment 44, and since these notches are spaced a ngularly by the same amount as the contact members 30, as stated, this will provide a simple and effective means for indexing the contact assem blies 35 relative to the contacts 30. The invention also provides stop means limiting the num-' ber of pairs of contacts 30 engaged by each contact assembly 35. It will be noted that there are twelve notches 45 and that those at each end are relatively rounded and deeper at their outer edges 55 than the intermediate notches. Thus although the roller 58'will readily move into and out of the intermediate notches, the outer edge 55 of each of the two end notches extends out a substantial distance from the axis of shaft 25 such that when the roller 50 is engaged in one of these end notches, the arm 47 will not readilyswing out to permit further rotation of the shaft. With this arrangement, if there were only two of the contact assemblies 35, each would have op erative relation with twelve pairs of contacts'3ll, and these two end notches in the plate 44 would serve as stops limiting rotation of shaft 25 to 180 and thereby limiting each contact assembly to engagement with one-half of the contacts Since there are four contact assemblies 35* in the drawing, rotation of rotor 12 through will provide for reaching all of the paired contacts 30 with a contact'assembly 35, and an additional stop member is accordingly provided lim iting rotation of the rotor to approximately 90f. This stop member is shownas an arm 60 seanother cured by a bolt B l to the plate 44 and having its radially inner end 62 cut out arcuately to engage the collar 46 and thereby to hold the arm rigid with relation to plate 44. The outer end of this arm 60 extends out a sufficient distance to engage roller 50 and thereby to serve as astop limiting counterclockwise rotation of shaft 25 as 'viewed in Fig. 1. As shown in Fig. .1, the arm 6.0 is in position such that there are six notches 45 for engagement with roller 50, thus providing that each contact assembly 35 can engage with six of the pairs of contacts 30.

It will also be noted that plate 44 is provided with additional bolt holes 65 so arranged that arm '60 can be readily shifted to vary the number of notches 45 which can be engaged by the roller '50, such variation being for the purpose of changing the number of pairs of contacts 30 with which each contact assembly 35 can be brought into register. For example, in connection with the rearrangement of the parts as described to form an 8-position, 3-circuit switch, the arm 6|! would be shifted sufficiently for bolt iii to engage in the next hole 65, thus leaving eight of notches 45 for engagement with roller 50, and still further variations may be carried out in similar fashion. It will accordingly be seen that this construction provides for arranging the stationary contacts 30 in groups, each of which can be independent of the other groups and operates with its own contact assembly 35 on the rotor, and each of which can thus serve to control a diiferent group of circuits. The number of these groups and the number of contacts in each group is determined by the number of movable contact assemblies, and the notched member 44 and arm 60 provide for limiting rotation of the rotor to the proper fraction of a complete revolution in accordance with the number of paired contacts in each group.

It will accordingly be seen that the present invention provides a multiple-contact switch having a variety of structural and operational advantages. It is made of component parts which are quite simple and inexpensive to produce, and in addition many of these parts are duplicates of each other thus minimizing their production cost. The switch is highly compact and affords special advantages from the standpoint of the saving of space in comparison with multiple-circuit switches which require separate rotors mounted in axially spaced relation along the central shaft. The switch of the invention lends itself particularly satisfactorily to production in a variety of sizes depending upon the number of circuits to be controlled, and also each such switch may be quickly and easily adapted by simple rearrangement of its parts to vary the number of groups of circuits controlled and the number of circuits in each group.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A switch of the character described, comprising, in combination, a pair of plates, means for mounting said plates in substantially parallel spaced relation, a rotor mounted between said plates for rotation about an axis substantially normal to said plates, a multiplicity of electrical contacts carried by each of said plates and cireumierenti-ally arranged in spaced relation about said axis, each contact being substantially di rectly opposite a contact in the other said plate, a plurality of contact assemblies carried by said rotor, each of said contact assemblies being adapted upon rotation of said rotor for selective engagement with opposed pairs of said contacts to provide an electrical connection therebetween. a member mounted for rotation with said rotor and having a multiplicity of notches along the periphery thereof, a pawl pivotaily connected with one of said plates and adapted to engage in said notches in said notched member, a spring positioned to urge said pawl into a position of engagement with said notched member, said pawl cooperating with said notched member to index said rotor for accurate register of each of said contact assemblies with a pair of said contacts, and an arm adjustably secured to said notched member for engagement with said pawl to provide a stop limiting rotation of said rotor in one direction and thereby limiting each of said contact assemblies to engagement with a predetermined number of said pairs of contacts, said adjustable connection of said arm to said notched member providing for variation in the number of pairs of contacts engageable by each of said contact assemblies.

v 2. A switch of the character described comprising, in combination, a pair of plates, means connecting said plates in substantially parallel spaced relation, a rotor positioned between said plates, means mounting said rotor for rotation relative to said plates about an axis substantially normal to said plates, a multiplicity of electrical contacts carried by each of said plates and circumferentially arranged in spaced relation about said axis, each contact being substantially directly opposite a contact in the other said plate, said rotor being a substantially circular plate of insulating material having a radius greater than the radial distance from the axis thereof to each of said contacts to form an insulating shield between each of said pairs of contacts, said rotor having a plurality of symmetrically spaced and radially arranged slots in ,the outer edge thereof, and a contact assembly mounted in each of said slots, each of said contact assemblies being adapted upon rotation of said rotor to engage opposed pairs of said contacts to provide an electrical connection therebetween.

3. A switch of the character described comprising, in combination, a pair of annular contact plates of generally rectangular configuration, each of said contact plates being formed of nonconducting material and each having legs integrally formed on one side thereof at each corner, each of said contact plates having on its other side a pair of lugs integrally formed at diagonally opposite corners, said contact plates being assembled with said lugs innermost and alternately arranged to maintain said plates in spaced and substantially parallel relation, a pair of switch plates secured to said legs of said contact plates by bolts passing axially through said legs, a shaft mounted in said switch plates for rotation about an axis substantially normal to said contact plates, a multiplicity of electrical contacts carried by each of said contact plates and circumferentially arranged in spaced relation about said shaft, each said contact being substantially directly opposite a contact in the other said contact plate, a rotor mounted on said shaft between said contact plates for rotation relative to said.

contact plates, and a contact assembly carried by said rotor and adapted-upon rotation of said shaft for selective engagement with opposed pairs of said contacts to provide an electrical connection therebetween.

4. A switch of the character described comprising, in combination, a. pair of switch plates, 2. pair of annular contact plates positioned between said switch plates and each having a plurality of legs integrally formedon one surface thereof and spacer lugs formed on the other surface thereof, said contact plates'being assembled with said lugs innermost and arranged to maintain said plates in spaced and substantially parallel relation, bolts passing axially through said legs to secure said contact plates and switch plates together, a shaft mounted in said switch plates for rotation about an axis substantially normal to said contact plates, a multiplicity of electrical contacts carried by each of said contact plates and circumferentially arranged in spaced and opposite relation about said shaft, a rotor mounted for rotation with said shaft between said contact plates, a plurality of contact assemblies carried by said rotor and symmetrically arranged thereon, each of said contact assemblies being adapted upon rotation of said rotor for selective engagement with opposed pairs of said contacts to provide an electrical connection therebetween, the number of said contact assemblies being equal to a fraction of the number of contacts in each contact plate, detent means controlling rotational movement'of said rotor,to provide for accurate register between each said contact assembly and successive pairs of said contacts, and means cooperating with said detent means to limit the angular movement of said rotor to a predetermined fraction of a complete revolution substantially equal to the angular distance between adjacent contact assemblies thereon.

5. A switch of .the character described comprising, in combination, a pair of annular contact plates each having a plurality of legs integrally formed on one surface thereof and spacer lugs formed on the other surface thereof, said contact plates being assembled with said lugs innermost and arranged to maintain said plates in spaced and substantially parallel relation, a pair of switch plates, said contact plates being positioned between said switch plates, bolts passing axially through said legs and thereby securing said contact plates and switch plates together, a shaft mounted in said switch plates for rotation about an axis substantially normal to'said contact plates, a multiplicity of electrical contacts carried by each of said contact plates and circumferentially arranged in spaced relation about said shaft, a rotor positioned between said contact plates and mounted on said shaft for slidin movement axially thereof, means holding said shaft and rotor against relative rotation, a plurality of contact assemblies carried by said rotor and symmetrically spaced about the axis thereof, each said contact as-, sembly being adapted upon rotation of said rotor for selective engagement with opposed pairs 'offcontacts to provide an electrical connection therebetween, and said contact assemblies comprising resilient members adapted to be compressed parallel to the axis of said rotor upon engagement between a. pair of said contacts to maintain said rotor in alignment in said switch while permitting limited movement thereof on said shaft. I

WILLIAM CAR-L KUHLMAN.

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

UNITED STATES PATENTS Number Name Date 1,570,304 Hynes Jan. 19, 1926 2,036,731 Todd Apr. 7, 1936 2,067,557 Allison Jan. 12, 1937 2,186,949 Allison Jan. 16, 1940 2,436,750 Gray Feb. 24, 1948 2,447,718 Simpson Aug. 24, 1948 2,453,161 Schleicher Nov. 9, 1948 FOREIGN PATENTS Number Country Date 431,280 Great Britain July 4, 1935

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