US2974206A - Switch assembly - Google Patents

Description

March 7, 1961 Filed Dec. 16, 1958 R. D- MAY SWITCH ASSEMBLY 3 sheets-sheet 1 4 l I A [if J 1 l6 INVENTOR. 54

max/4,60 0 Amy Avon [rs March 7, 1961 R. D. MAY

SWITCH ASSEMBLY 3 Sheets-Sheet 2 Filed Dec. 16, 1958 INVENTOR. /CH4,0 0. A64) R. D. MAY

SWITCH ASSEMBLY March 7 1961 ,3 Sheets-Sheet 5 Filed Dec. 16, 1958 INVENTOR. e/c/mzo 0 m4) United States Patent 8 Claims. (Cl. 200-813) This invention relates to an electrical switch specially adapted for rapid opening and closing and for fluid actuation.

The prime object of the invention pertains to the provision of improvements in an electrical switch structure of the type in which a plurality of switches are rapidly operated in sequence for sequentially operating a plurality of circuits. A primary field of use for switch structures of this type is in electronic computers or data processors, where a series of electrical signals corresponding to predetermined data follow one another closely and are to be fed to selected ones of a plurality of available circuits.

2,974,206 Patented Mar. 7, 1961 In accordance with the present invention a mechanical switch construction is disclosed which is capable of opening and closing the circuit therethrough in a truly minimal period of time, which when closed has a minimal contact resistance and no appreciable contact bounce, and which may be manufactured on a production basis comparatively inexpensively and without requiring a high degree of precision either as to dimensions or as to the specifications of the materials employed. The structure of the present invention embodies improvements in the switch assembly disclosed in my pending application No. 743,055 filed June9, 1958.

To the accomplishment of the foregoing objects and such other objects as may hereinafter appear, the present invention relates to the construction of a quick acting switch assembly and a means cooperating therewith for actuating the switch, as defined in the appended claims In the switch structure of the present invention, a plurality of switch assemblies, miniaturized and assembled closely together, are actuated in sequence by high speed means for sequentially and rapidly operating the switches.

In this type of electrical switch, it is essential to attain to an optimum degree the following operating characteristics:

(1) The making and breaking of the switch contacts must be rapid and precise, since the particular circuit appropriate to a given'signal must be closed precisely. during the short time period that said given signal is present and must be fully open when other signals appropriate for other circuits are present,

(2) Since the signals have a minimal electrical magnitude, the contact resistance of the switches must be correspondingly low in order that excessive attenuation of the signals should not occur, and

(3) Contact bounce when the switch is closed must be obviated, since such contact bounce, even if it does not actually open the circuit, might so modulate the magnitude of the signal as to render it ineffective for the designed purpose. 7

It is the prime object of the present invention to devise a high speed sequential switch embodying these stated characteristics to a high degree.

With conventional switch arrangements the mechanical moving parts, even when miniaturized to an extreme degree, will nevertheless ordinarily have sufficient inertia and momentum so as not to be reliably actuatable in the short priod of time involved and still attain effective circuit closing without contact bounce or excessive contact resistance. It has been proposed that a plurality of switches of the general type here under discussion may be actuated sequentially by the impingement thereon of a moving stream of flowing fiuid such as air, the stream being moved from one switch to the next by means of a movable nozzle to produce sequential switch operation. This has the advantage of reducing the problem of inertia and momentum and of obtaining rapid sequential switch operation without causing any wear as between the actuator and the switches. The switch constructions useable with this type of actuator have been difficult if not impossible to manufacture on a production basis. their reliability leaves much to be desired, and the problem of contact bounce has not been solved satisfactorily.

and as described in the following specification, taken together with the accompanying drawings in which:

Fig. 1 is a perspective view of the sequential switch structure; 1 Fig. 2 is a cross-sectional view thereof drawn to an enlarged scale and taken in cross-section in the plane of the line 22 of Fig. 1;

Fig. 3 is a fragmentary view taken in cross-section in the plane of the line 3-3 of Fig. 2;

Fig. 4 is a fragmentary view taken in cross-sectionin the plane of line 44 of Fig. 2; Fig. 5 is an enlarged view of one of the switch assemblies and its mounting taken in cross-section in the plane of the line 55 of Fig. 4;

Fig. 6 is a view of Fig. 5 as viewed from the plane of the line 66 of Fig. 5, and showing a plurality of the switch assemblies as mounted in the switch structure; and

Fig. 7 is an enlarged view of parts shown in Fig. 5.

Referring now more in detail to the drawings, the

individual switch assemblies of the present invention,

generally designated as A, are shown mounted in operative position in a high speed sequential switch, generally designated as B. The sequential switch comprises a. housing including a ring-like side wall 2 with front and rear end caps 4 and 6 respectively, these parts of the housing being made of a suitable insulating material. The individual switch assemblies A are positioned serially, closely adjacent one another around a predetermined portion of the inner surface of the side wall 2, as best shown in Fig. 3 of the drawings, and a rotor generally designated as 8, is rotatably mounted within the housing, said rotor embodying an actuated part which is adapted to sequentially pass over the switch assemblies A and actuate them one after the other.

The individual switch assemblies A each comprises a base 10 formed of a suitable insulating material and provided with terminal ears 12 at opposite ends for mounting the same in the housing between the side wall 2 and the front and rear end caps 4 and 6, as best shown in Figs. 2 and 5 of the drawings. Conductive terminal posts 14 and 16 are mounted in the base 10 so as to extend downwardly therefrom, and these terminal posts extend through and project from the housing side wall 2 for ready access. The terminal posts 14 and 16 are located at opposite ends of base 10 and are provided with reduced portions 14 and 16*- respectively.

Each of the switch assemblies A includes stationary and movable contacts which are designed and constructed on principles calculated to produce the desired operating characteristics above described. Having reference to Fig. 5, the stationary contact comprises a screw adjustable} member 18 adjustably movable to fixed positions on a support 20 integral with thebase 10 andconductively connected by means of a bridging plate 22 to the terminal post 1 6 at its reduced end 16*. Desirably, the meeting faces of these elements are soldered as at 24-24 to improve the electrical connection. The movable contact of this switch assembly comprises an elongated spring strip 26 fixed at one. end to said base '10, free at its other end for coaction with said stationary contact 18 and fulcrumed on said support 20 at a point closely adjacent the stationary contact 18.

More specifically, this spring strip, narrowed at its main or operating region (see particularly Fig. 6) has a broadened terminal part 28 which is anchored to a support 30 integral with the base 10 by means of a bolt 32 threadedly received by this support 30, the said part 28 being conductively connected to the terminal post 14 at its reduced portion 14*, as best shown in Fig. 5, the meeting faces of these elements being also preferably soldered as at 34 to improve the electrical connection therebetween. The operating portion of. the spring strip 26 is fulcrumed at the point 36 (see particularly Figs. and 7), said fulcrum point dividing the spring strip 26 into an unequal-arm lever with a long actuating arm 516 and a short contact arm 26 said short contact arm being adapted for switch coaction with the stud portion 18 v of the stationary contact 18.

The clearance between the stationary stud contact 18 and the movable contact arm 26 when in open circuit, is of the order of .003 of an inch. By reason of the division of the movable contact into a very long actuating arm 26 and a very short contact arm 26 an inward deflection or flexing of the spring strip 26 in response to an actuating impulse will result in a rapid closing of the switch contact 18 and 26 Conversely, upon return unflexing movement of the spring strip 26 when released from an actuating impulse, the switch contacts will move rapidly to open position, also by virtue of the leverage supplied by the long actuating arm 26*. The switch contacts 18. and 26 will engage with such interface force as to produce a contact resistance of an exceedingly low order. Furthermore, since the engagement between the switch contacts, once engaged, is not materially sensitive to added incremental movements in the deflection or flexing of the actuating part of the movable contact member, contact bounce is substantially minimized or obviated, this characteristic being further improved by the manner in which the fulcrum is constructed as now to be described.

The fulcrum 36 is made to comprise a fulcrum pivot stud 38 integral with the support and arranged to contact one side of said spring strip 26 and a fulcrum spring biased element 40 contacting the other side of said spring strip, as best shown in Fig. 7 of the drawings. This spring biased element 40. preferably comprises the end of a pressure leaf spring 42 centrally seated in a projection 44 integral with the base 10, the other end 46 of leaf spring engaging the far end of the long actuating arm 26 This arrangement accomplishes a number of desirable results. The spring pressure exerted by the end 40 of the leaf spring 42 aids in stabilizing the movable contact by dampening any tendency of the movable contact to vibrate, thereby further minimizing any tendency toward contact bounce. Also the described fulcrum structure permits some longitudinal sliding movement of the contactarm 26 in both the flexing and return movements, of the movable contact and thereby there is a produced desirable wiping and cleaning action of the switch contacts.

A most effective way to provide the force to flex the movable contact of the switch elements is by means of a flowing stream of fluid such as air. To that end the rotor 8 comprises a body 48 (see Fig. 2) fixed to the shaft 50 of the rotor, the shaft being journaled in the front and rear end caps 4 and 6 by means of bearings 52v and 54 respectively. The shaft 50 at one of its ends has, an inwardly extending passage 56, which communicates by means of'a radial passage 58 with a nozzle 60 located so that as the rotor 8 revolves, the nozzle is brought into registration with and passes over the long arms 26 of the movable contacts 26 of the successive switch assemblies A. The stream of air or other fluid escaping from the nozzle 60 impinges upon the long arms of the movable contacts 2 6 as the shaft 50 revolves, thus imparting the deflecting or flexing movement to the movable contacts for operating the switches.

A large number of switch assemblies may be mounted in a single housing B, and the rotor 8 may be rotated at a high speed on the order of many hundred revolutions per minute. The nature of the construction of the switch assemblies A is such that although each will be subjected to the circuit-closing action of the flowing stream of fluid only for a small fraction of a second, each of the switches will reliably and effectively close the circuit therethrough during that short period of time without any appreciable contact bounce and with a minimal intercontact resistance. The circuit will be opened just as promptly when the stream of air has passed the switch, thus ensuring that each switch will open before the next succeeding switch has closed. Accordingly, through the useof the structure here disclosed a high speed sequential switch unit may be produced which will function accurately and reliably and which will not be affected by wear to any appreciable degree.

While but a single embodiment of the present invention has been specifically disclosed, it will. be. apparent that many variations may be made therein all within the scope of'the instant invention as defined in the following claims.

I claim:

1. A switch assembly comprising a support, a stationary contact connected to said support,fa movable contact on said support comprisingan elongated spring strip fixed at one end to said support, free at its other end for coaction with said stationary contact and fulcrumed on said support at a pointclosely adjacent the stationary contact, said fulcrum point dividing the spring strip into an unequal-arm lever with a long actuating arm and a short contact arm, and means associated with said long actuating arm for flexing the same to move and operate the short contact arm.

2. The switch assembly of claim 1 in which said last recited means comprises mechanism for impinging a fluid on said long actuating arm to flex the same,

3. A switch assembly comprising a support, a stationary contact connected to said support, a movable contact on said support comprising an elongated spring strip fixed at one end to said support, free. at its other end for coaction with said stationary contact and fulcrumed on said support at a point closely adjacent the stationary contact, said fulcrum point dividing the spring strip into ,an unequal-arm lever with a long actuating arm and a short contact arm, the fulcrum at said fulcrum point comprising a fulcrum pivot stud contacting one side and a fulcrumspring biased element contacting the other side of said spring strip, and means associated with the long actuating arm of said spring strip for flexing the. same to move and operate the short contact arm thereof.

4. A switch assembly comprising a support, a stationary contact connected to said support, a movable contact on said support comprising an elongated spring strip fixed at one. endto said support, free at its other end. for coaction with said stationary contact and fulcrumed on said support at a point closely adjacent the stationary contact, said fulcrum point dividing the spring strip into an unequal-arm lever with a long actuating arm and a short contact arm, a pressure leaf spring anchored to said support, the fulcrum at said fulcrum point comprising a fulcrum pivot stud contacting one side of said springstrip and an end of said pressure leaf spring contacting the other side of said spring strip, and means associated with said long actuating arm for flexing the same to move and operate the short contact arm.

5'. A sequential switch comprising a housing, a pin rality of switch assemblies serially mounted thereon, each of said switch assemblies comprising a support, a staiionary contact connected to said support, a movable contact on said support comprising an elongated spring strip fixed at one end to said support, free at its other end for coaction with said stationary contact and fulcruined on said support at a point closely adjacent the stationary contact, said fulcrum point dividing the spring strip into an unequal-arm lever with a long actuating arm and a short contact arm, the latter being movable into and out of engagement with said stationary contact, and mechanism for sequentially operating the switch assemblies comprising a rotor mounted in said housing having an actuating part movable over the long actuating arms of said switch assemblies for flexing the same in sequence and for thereby operating the short contact arms of the spring strips of said assemblies in sequence.

6. The sequential switch of claim 5 in which the fulcrum at the fulcrum point of each switch assembly comprises a fulcrum pivot stud contacting one side and a fulcrum spring biased element contacting the other side of the spring strip of the switch assembly.

7. In the sequential switch of claim 5, a pressure leaf spring anchored to the support of each switch assembly, the fulcrum at the fulcrum point of each switch assembly comprising a fulcrum pivot stud contacting one side and an end of said pressure leaf spring contacting the other side of the spring strip of such switch assembly.

8. The sequential switch of claim 5 in which the actuating part on said rotor comprises a nozzle in communication with a source of fluid, said fluid upon operation of the rotor being flowed through the nozzle and being caused to impinge in sequence upon the long arms of said spring strips of the switch assemblies for switch operation.

References Cited in the file of this patent UNITED STATES PATENTS 2,418,068 Cornelius Mar. 25, 1947 2,558,235 Castellano June 26, 1951 2,596,171 Rabinow May 13, 1952 2,649,520 Hartz Aug, 18, 1953 2,773,951 Finlay et a1 Dec. 11, 1956 2,789,173 Kaminky Apr. 16, 1957 2,852,636 Block et al. Sept. 16, 1958 2,855,473 Rabinow Oct. 7, 1958

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