US3042768A - Switch assembly - Google Patents

Description

July 3, 1962 R. D. MAY

SWITCH ASSEMBLY 5 Sheets-Sheet 1 INVENTOR. Z/CHAEO 0. MA)

l I Jflvm m u m m an m a a a w p i m J 6 k n H J m l Z July 3, 1962 MAY SWITCH ASSEMBLY 3 Sheets-Sheet 2 Filed June 19, 1958 INVENTOR. 5/0/4217 0. M4)

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SWITCH ASSEMBLY July 3, 1962 3 Sheets-Sheet 3 Filed June 19, 1958 mmvroa. ,E/(JHAED 0. MAY

BY ydwdrww A Tme/V/E Y;

States Units The present invention relates to an electrical switch specially adapted for rap-id opening and closing and for fluid actuation, and to means for actuating it.

There is at the present time a great and increasing demand for electrical switches which can reliably open and close thecircuits in' which they are connected in a very short period of time on the order of a fration of a secondfand for such switches a plurality of which may be assembled in a singleassembly for individual sequential operation. Aprimary field of use for devices of this type is in electronic'computers or data processors, wherea 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. It is essential, in devices of this type, that the particular circuit appropriate to a given signal be closed precisely during the short period of time that said given signal is present, and that the switch be open when other signals appropriate for other circuits are present. 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 should not occur. It is also exceedingly imortant that there be no contact bounce while the switch is closed, since such bounce, even if not actually opening the circuit during the time that the signal is being applied thereto, might so modulate the magnitude of the signal as to render it ineffective for its design purpose.

T o produce a mechanical switch which will satisfy these requirements is no mean task. With conventional switch arrangements the mechanical moving parts, even whenminiaturizcd to an extreme degree, will nevertheless ordinarily have suflicient inertia and momentum so as not to be reliably actuatable in the short period of time involved and still attain eiiective circuit closing without vantage of rapid sequential switch operation without cansing any wear as between the actuator and the switches. The switch constructions useable with this type of actuator have been difilcult if not impossible to manufacture on a production basis, their reliability leaves much to be desired, and the problem of solved satisfactorily.

In accordancewith 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'whenclosed' has a minimal contact resistance and .no appreciable contact bounce, and which may be manufactured on a'produ'ctionbasis comparatively inexpensively and 'without requiring a high degree of precision either'as. to dimensions or as to the specificaticns of 'the'materials employed.

The switch comprises a fixed and a movable contact, the latter normally being slightly spaced from the former in orderto produce an open circuit and being movable into engagement with the former in order to close the circuit through the'switch. The fixed contact may take the form of a-projecting pin. The movable contact extends atleast partly around the fixed contact and includescontact bounce has. not been" P ice 2. a first part located to one side of the fixed contact, that first movable contact part being connected to a second part which extends to the opposite side of the fixed contact and there includes a flexible portion mounted'so as to be permitted to flex when appropriately actuated, as by the impingement thereupon of a. stream of flowing fluid such as air. When this flexible portion ofthe movable contact does flex the eflective length of the movable contact decreases and the first part thereof is pulled toward and into engagement with the fixed contact. When the fluid stream no longer impinges on the movable contact it will return to its initial open-circuit position, being urged to that position by some suitable" biasing means, which may be the inherent resiliency of the flexible portion of the nrovable contact itself. The distance which the first part of the movable contact must traverse between closed and open circuitpositions is quite small, on the order of a few 'thousandths of an inch, so that the opening and closing of the switch'can be accomplished very quickly. The flexing pressure exerted on the fixed contact by the stream of fluid constantly urges the two contacts together, thus minimizing the intercontact resistance.

In the form here specifically disclosed the movable con-' the U and close to the portion which connects the parallel legs of the U. Exceptionally good results have been obtained with a movable contact thus configured, particularly when both oft'helegs of the U are flexible and are simultaneously caused to flex. To accomplish this re sult it is preferred that two individual streams of flowing fluid be provided, each acting upon a different leg of the movable contact ofa given switch at substantially the same time. As here disclosed thisresult is accomplished by providing a pair of nozzles from which separate fliud streams escape; the nozzles being spaced from one another by 'a distance substantially equal to the spacing between the legs of the U, means being provided to ensure that the streams escaping from each nozzle engage the appropriate legs of the movable contact at the same time. This means may comprise a plate located adjacent the movable contact, interposed between the nozzles and the movable contact, and provided with a pair of apertures each registering with one of the legs of the movable contact, the nozzles being positioned to register respectively with the apertures. It has also been found desirable to elongate thenozzles inthe direction of their movement relative to the switch in order to ensure thatthe switch 7 Will remain firmly closed during. the entire period of time when it is desired that that condition exists.

To the accomplishment of the above, and to such other objects as my hereinafter appean the present invention relates to the construction of a quick acting switch assembly and of means cooperating therewith for actuating the switch, as defined in the appended claims andas described in this specification, taken together with the accompanying drawings,-in which:

FIG. 1 is a-top plan-view, partially broken away, of a,

vFIGJS is a cross sectional view taken along the line 5 5 of FIG. 4;

-FIG. 6 is a cross sectional view taken along'the line 6-6 of FIG. 4;"

FIG. 7 is a cross sectional" view taken along the'line 7--7 of FIG. 4;

FIG. 8 is an end elevational view bly of FIG. 4;

FIG. 9 is a top plan view, on an enlarged scale, of the movable contact employed in the switch assembly of FIG. 4;

FIG. 10 is an end elevational view of the movable contact of FIG. 9;

FIG. 11 is a side elevational view thereof;

FIG. 12 is a bottom plan view of one of the nozzles employed in the sequential switch of FIG. 1;

FIG. 13 is a side elevational view thereof;

FIG. 14 is a cross sectional view taken along the line 14--14 of FIG. 13; and

FIG. 15 is a top plan view of the nozzle of FIG. 12.

The individual switch assemblies of the present invention, generally designated A, are shown mounted in operative position in a high speed sequential switch generally designated B. The sequential switch comprises a housing including a ring-like side wall 2. with front and rear end caps 4 and 6 respectively. The individual switch assemblies A are positioned serially adjacent one another around a predetermined portion of the inner surface of the side wall 2, and a rotor generally designated 8 is rotatably mounted within the housing so as to sequentially pass over the switch assemblies A and actuate them one after the other.

As may best be seen from FIGS. 3-11, the individual switch assemblies A comprise a base 10 formed of some suitable insulating material and provided with cars 12 at opposite ends for facilitating their mounting within the sequential switch housing, as will become apparent hereinafter. Conductive terminal posts 14 and 16 are mounted in the base 10 so as to extend downwardly therefrom, the terminal posts 14 and 16 being provided with enlarged heads 14a and 16a. The terminal post 16 is located at one end of the base 10, with its enlarged head 16a resting on a ledge 18. The terminal post 14 is located adjacent the opposite end of the base 10 with its enlarged head 14a received within an appropriately shaped recess 20 in the upper surface of the base 10. The terminal posts 14 and 16 may be retained in place through friction or in any other appropriate manner and, for a reason hereinafter to be explained, it is preferred that the terminal post 14 be adjustably rotatable about its axis upon the application of sufiicient force thereto, but adapted to be retained in rotated position when that force is removed. Mounted in the head 14a of the terminal post 14, and preferably otf-center with respect to its axis, is the fixed contact 22, which may take the form of a pin or rod which extends up from the upper surface 24 of the base 10 for an appreciable distance. The fixed contact 22 may be resilient, although this is not essential.

The movable contact, generally designated 26 an shown in detail on an enlarged scale in FIGS. 9-11, may be formed from a single length of resiliently flexible conductive material. As here specifically disclosed it has a substantially U-shape and comprises a pair of parallel legs 28 and 30 connected at one end by a cross piece 32 defining the base of the U. The contact may be formed from a round wire having a diameter of approximately .012 inch, in which case it has been found desirable to flatten appreciable lengths of the legs 28 and 30 extending therefrom to a width of approximately .029 inch and a thickmess of approximately .004 inchin order to improve the functioning thereof as described below. A portion 28a of the leg 28 may extend beyond the corresponding portion 30a of the leg 30 and is provided with a downturned portion 28b which is adapted to be received in an aperture in the head 16a of the terminal post 16, so that electrical connection with the movable contact 26 may be made via the terminal post 16. In the specific embodiment disclosed the cross piece '32 defines a first part of said movable contact 26, and the legs 28 and 30 define a second part thereof, the portions of said legs 28 and 30 spaced of the switch assemabove the surface 24 defining flexible portions of said second part of said movable contact 26.

The movable contact 26 is mounted on the base A so that the fixed contact 22 is received inside the parts adjacent the cross piece 32 thereof. The cross piece 32 may be narrowed at its central portion 32a (as by being unflattened when compared with the legs 28 and 30), and the fixed contact 22 may be positioned closely adjacent the narrowed portion 3211 but normally spaced therefrom by a small distance, which may be as little as a few thousandths of an inch.

The leg portions 28a and 30a of the movable contact 26, which are remote from the cross piece 32, are secured to the base 10 in any appropriate manner, thereby supporting the movable contact 26 in position. As here disclosed the base 10, adjacent the terminal post 16, is provided with an upwardly extending portion 34 having a pair of upwardly facing surfaces 36 on which the contact portions 28a and 30a are adapted to rest, lugs 38 extending up outside the contact arm portions 28a and 30a. A plate 40 extends over the contact arms 28a and 30a and is secured to the base portion 34 by means of screw 42 which passes down into a tapped aperture 44 in the base 10. The plate 40 is provided with a downwardly extending flange 46 receivable in a recess 48 formed in the upper surface of the base portion 34 and extending inside and between the contact arm portions 28a and 30a. .Thus, as may best be seen from FIGS. 5-8, the plate 40 clamps the contact arm portions 28a and 30a between itself and the base portion 34, the positions of the clamped contact arm portions 38a and 30a being fixed by the lugs 38 and the flange 46. The end 281; of the contact arm portion 28a extends out beyond the base portion 34 so as to be engageable with the terminal post head 16a.

As here specifically disclosed the plate 40 extends over the movable contact 26 so as to cover it substantially completely, and is secured at its other end to the base 10 by means of screw 50 received within tapped aperture 52 in the base 10. It preferably closely overlies the leg portions 28 and 30 of the movable contacts 26 so as to provide a guide or support for the normal position of those legs. It is provided at appropriate points along its length with a pair of apertures 54 and 56, each positioned over a given one of the contact arms 28 and 30 so as to register therewith, the apertures 54 and 56 being staggered longitudinally of the plate 20.

Because the contact arm portions 28a and 30a are supported above the upper surface 24 of the base 10, the flattened and therefore readily flexible arms 28 and 30 are spaced from the upper base surface 24. It therefore is desirable that some means be provided for supporting the cross piece 32 against movement toward the base 10. To this end the plate 40, adjacent the cross piece 32, is provided with an inwardly extending protruding portion 58 on which the cross piece 32 is adapted to rest, that portion 58 being provided with an aperture 60 through which the fixed contact 22 freely extends upwardly to a point inside the parts of the movable contact 26 and closely adjacent the portion 32a of the cross piece 32. If desired, an aperture 62 may be formed in the plate 40 in line with the fixed contact 22 so that the latter may be observed.

Reference has previously been made to the fact that the terminal post 14 may be rotated relative to the base 10 and that the fixed contact 22 is eccentrically mounted on the terminal post 14. The purpose of this arrangement is to permit adjustment of the spacing between the fixed contact 22 and the cross piece 32 of the movable contact 26. The aperture 62 in the plate 40 permits visual inspection of the relative positions of the fixed and movable contacts as the former is adjusted.

With the movable contact 26 in its normal position its cross bar 32 is normally slightly spaced from the fixed contact 22, as has previously been stated. If now the arms 28 and 30 of the movable contact 26 are caused to flex, preferably in a direction toward the base 10 above which they are positioned, the effective length of the movable contact 26 measured in a direction parallel to the plate 40 will decrease, particularly although not necessarily when the cross piece 32 is supportedagainst movement in the direction of flexure of the arms 28 and 30. As a result the cross piece 32 will move to the left as viewed in IGS. 4 and 5 and will therefore come into contact with the fixed contact 22, thereby closing the circuit between the terminal posts 14 and 16. The actual distance which the cross piece 32"must move is quite small, so that there is an infinitesimal time delay involved in closing the switch. Moreover, so long as force is exerted on the contact arms 28 and 30 causing them to flex, the cross piece 32 will beforcibly pulled into engagement with the fixed contact 22, thereby ensuring minimization of intercontact resistance and effectively eliminating contact bounce. When the flexing force is removed the movable contact 26 will resume its normal condition, being biased thereto by its own inherent resiliency or if desired by some external biasing means. The cross piece 32 will move away from the fixed contact 22, and the circuit through'the switch will be opened.

A most elfective way to provide the flexing force is by means of a flowing stream of fluid such as air. To that end, and making reference particularly to FIGS. 1 and 2, the rotor 8 comprises a body 64 mounted on shaft 66, the shaft being journaled in the front and rear end caps 4 and 6 by means of bearings 68 and 70 respectively. The shaft 66 at its left hand end as viewed in FIG. 2 has an inwardly extending passage 72 which communicates, by means of lateral aperture 74 and shaft portion 75 of reduced diameter, with a pair of radially extending passages 76 and 76 in the body 64, nozzles 78' and 78' being located at theends of the passages 76 and 76" respectively. Those nozzles are spaced from one another axially of the shaft 66 by a distance corresponding to the longitudinal spacing between the apertures 54 and 56 in the plate 40' of the switch assembly A and are spaced from one another circumferentially by a distance corresponding to the lateral spacing between the switch apertures 54 and 56. The nozzles 78 and 78 are so located that as the rotor A rotates they are brought into registration with and pass over the-apertures 54' and 56 respectively of the switch assemblies A, which latter are mounted in the housing B by, having their ears 12 clamped between the ring 2 and the end caps 4 and 6, their terminal posts 14 and 16 passing through apertures 79 in the housing side wall 2. The end cap 6 is provided with an aperture 8%) in line with the aperture 72 in the shaft 66, to which a suitable source of fluid under pressure is adapted to be' connected. A rotary seal 82 is positioned in' the end cap'fi'inwardly of the bearing 76 so that the fluid under pressure will pass through the aperture 80 and passage72' into the passages 76 and 76, escaping therefrom via the nozzles 73 and 78'.

The two nozzles 78 and 78 cooperate with the particular form of movable contact 26 here specifically disclosed so that the stream of air or other fluid escaping from the nozzles 78 and 78' will substantially simultaneously impinge upon the movable contact arms 28 and 30 respectively. This occurs because the leading edge of each nozzle will register with the corresponding aperture 54 or 56 at substantially the same instant. As a result both of the arms 23 and 30 of the movable contact 26 will flex downwardly at substantially the same time, thus minimizing any tendency of the movable cont-act 26 to rock. Similarly, the flexing force of the fluid'stream will be removed from the contact arms 28 and 30 at substantially the same instant.

It has been found that best results are obtained when the tips 78a of the nozzles are elongated in the direction of movement of the nozzles relative to the switches. By reason of this elongation the flexing force exerted on the movable contact arms 28 and 30 is maintained at a substantially uniform valueduring substantially the entire time that the nozzles are passing over the switch assem blies.

A large number of switch assemblies may be mounted in a single housing B and the rotor 8 may be rotated at a high speedon 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 forasrnall 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 use of 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 em-bodiment'of the present invention has been here specificallydisclosed, 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 base, a fixed contact operatively connected thereto, and a movable contact operatively connected to said base and comprising a first part located to one side of and normally spaced from said fixed contact in line of a given direction and a second part connected to said first part and extending to the opposite side ofsaid fixed contact, said second part including a flexible portion mounted on said base so as to be permitted to flex in a direction other than said given line of direction, flexure of said portion thereby causing said first part of said movable contact to move in said given directiontoward and to engage said fixed contact.

2. The switch assembly of claim 1, in which said fixed contact is adjustably connected to said base so as to be adjustably positionable in said given direction closer to or farther from said first part of said movable contact.

3. The switch assembly of claim 1, in which said fixed contact iseccentrical ly connected to said base so as to be adjustably positionable in said given direction closer to or farther from said first part of said movable contact.

4. A switch assembly comprising a base, a fixed contact operatively connected thereto, a movable contact comprising a pair of legs and an arm connecting said legs at one end, means operatively fixedly connecting said legs to said base at points remote from said arm, substantial portions of said legs between said connecting means and said arm being supported in a position spaced from said base, said leg portions being resiliently flexible, said legs at said one end thereof and said arm extending around said fixed contact and being normally spaced therefrom in a direction other than the direction between said base and said leg portions, and means for supporting said arm against movement toward said base, whereby flexure of said legs toward said base will draw said arm into engagement with said fixed contact.

5. In the switch assembly of claim 4, a plate extending above said movable contact, and having a pair of apertures therethr-ough each registering with one of said legs.

6. The switch assembly of claim 5, in which said plate is separate from and secured to said base and constitutes at least in part means for fixedly connecting said legs to said base.

7. The switch assembly of claim 5 in which said plate is separate from and secured to said base and constitutes at least in part said means for fixedly connecting said legs to said base, and a portion of said plate underlying said arm and constituting at least in part said arm supporting means.

8. The switch assembly of claim 4, in which said leg portions are thin and fiat and extend widthwise in a plane substantially parallel to said base.

9. The switch assembly of claim 4, in which said legs and arms are thin and flat and extend widthwise in a plane substantially parallel to said base, said arm having a portion of narrower width opposite said fixed contact.

10. A switch assembly comprising a base, a fixed contact operatively connected thereto, a movable contact comprising a pair of legs and an arm connecting said legs at one end thereof, means operatively fixedly connecting said legs to said base at points remote from said arm, substantial portions of said legs between said arm and said points being mounted in a manner to permit fiexure thereof, said leg portions being resiliently flexible, said legs at said one end and said arm extending around said fixed contact and being normally spaced therefrom in a direction other than the direction of flexure of said legs, and means for supporting said arm against movement in the direction of flexure of said legs, whereby flexure of said legs will draw said arm into engagernent with said fixed contact.

11. A switch assembly comprising a base, a fixed contact operatively connected thereto, and a movable contact operatively connected to said base and comprising a first part located to one side of and normally spaced from said fixed contact in a given direction, and a second part connected to said first part and extending to the opposite side of said fixed contact, said second part including a flexible portion mounted on said base so as to be permitted to flex in a direction other than said given direction, flexure of said portion thereby causing said first part of said movable contact to move in said given direction toward and to engage said fixed contact, said movable contact being substantially U-shaped, the legs of said U comprising said second part of said movable contact and being fixedly secured to said base at points therealong remote from the end thereof connecting said legs, said end of said U comprising said first part of said movable contact, said fixed contact being located inside said U.

12. The switch assembly of claim 11, in which said fixed contact is adjustably connected to said base so as to be adjustably positionable in said given direction closer to or farther from said first part of said movable contact. 13. The switch assembly of claim 11, in which said fixed contact is eccentrically connected to said base so as to be adjustably positionable in said given direction closer to or farther from said first part of said movable cont act.

14. In combination with the switch of claim 11, a pair of nozzles spaced from one another corresponding to the spacing between the legs of said U, a source of flowing fluid communicating with said nozzles, and means for positioning said nozzles opposite said legs and for causing said flowing fluid to impinge upon said legs when it is desired to close said switch.

15. In combination with claim 11, a plate positioned over the legs of said U and having a pair of apertures therethrough each registering with one of said legs, and means located over said plate for producing flow of fluid. through each of said apertures when it is desired to close said switch, said flowing fluid, in'passing through said apertures, impinging on said legs and causing them to flex.

16. In combination with the switch of claim 11, a plate positioned over the legs of said U and having a pair of apertures therethrough each registering with one of said legs, a pair of nozzles spaced from one another corresponding to the spacing between said apertures, a source of flowing fluid communicating with said nozzles and means for positioning said nozzles .opposite said apertures and causing said flowing fluid to pass through said apertures and impinge upon said legs, causing them to flex when it is desired to close said switch.

17. A sequential switch comprising a housing, a plurality of the switch assemblies of claim 11 serially mounted therein, and a movable actuator in said housing comprising a pair of nozzles spaced from one another by a distance corresponding to the spacing between the legs of said switches, and a source of flowing fluid com municating with said nozzles, said actuator being movable to bring said nozzles sequentially into registration with the legs of individual switches.

18. The sequential switch of claim 11, in which the tips of said nozzles are elongated in the direction of nozzle movement, said nozzles being moved in a direction substantially perpendicular to the length of said legs.

19. A sequential switch comprising a housing, a plurality of the switch assemblies of claim 11 serially mounted therein, each of said switch assemblies comprising a plate positioned over the legs of said U and having a pair of apertures therethrough each registering with one of said legs, a movable actuator in said housing comprising a pair of nozzles spaced from one another by a distance corresponding to the spacing between said apertures, and a source of flowing fluid communicating with said nozzles, said actuator being movable to bring said nozzles sequentially into registration with the apertures in the plates of individual switches.

20. The sequential switch of claim 19, in which the tips of said nozzles are elongated in the direction of nozzle movement.

References Cited in the file of this patent UNITED STATES PATENTS 1,936,356 'Free Nov. 21, 1933 2,773,951 Finlay et al. Dec. 11, 1956 2,796,475 Finlay June 18, 1957 2,835,761 Crownover May 20, 1958

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