US2903531A - Alternating current switch - Google Patents

Description

Sept. 8, 1959 P. H. WINTER ALTERNATING CURRENT SWITCH Filed April 29, 1957 I//// BY 2 Sheets-Sheet 1 INVENTOR HQI/L JY, M1175@ ATTOREYS Sept. 8, 1959 P. H. WINTER 2,903,531

ALTERNATING CURRENT SWITCH Filed April 29, 1957 2 sheets-sheet 2 INVENTOR R21/L C M11/TEE Y rg@ ATTORNEYS Il v ALTERNATING CURRENT SWITCH Paul H. Winter, Syracuse, NX., assigner to Pass Si Seymour, Inc., Syracuse, N.Y., a corporation of New York Application April 29, 1957, Serial No. '655,787

Claims. (Cl. 200-67) This invention relates to electric switches for illumination, light duty appliances and kindred uses, adapted for flush mounting behind a cover or wall plate and being of the self-quenching type operable without snap action on alternating current.

It is a general object of the present invention to provide a novel and improved alternating current switch of the type described, in which both the opening and closing of the circuit or circuits is positive and wholly under the control of the operator, yet without the noisy operation of the common form of snap switc More particularly, it is an object of the invention to provide in an alternating current switch a at, conducting spring extending generally longitudinally of the switch housing, anchored at one end therein, arranged to have the free end thereof cooperate with one or selectively with two contacts rigidly mounted near the opppsite end of the housing and under the positive control, in each direction of movement, of a tumbler arranged for oscillation arcuately in planes parallel to the general plane of the spring and which acts by engagement of both sides of au intermediate, deected section of the spring.

An important object of the invention resides in providing a unique arrangement for mounting each combination spring end-support and terminal plate and each fixed contact support and terminal plate in the end walls of the switch housing, whereby a plurality of such switches may be mounted closely side by side without interferring with access to the terminals.

Another important object of the invention resides in the arrangement of the tumbler with an over-center spring and two spaced surfaces adapted to alternately engage a single resilient bumper block secured to the housing to limit and silence the operation of the tumbler in each direction of throw.

A still further important object of the invention resides in the cooperating arrangement of the intermediate deflected area of each contact-carrying spring `and the actuating lugs therefor depending from the tumbler, whereby each lug engages one side of the Adeflected area of the spring and alone controls its movement and maintains its contact engagement in one dirction Without hindrance from the other.

Other and further features and objects of the invention will be more apparent to those skilled in the Yart upon a consideration of the accompanying drawing and following specification wherein are disclosed several exemplary embodiments of the invention, with the understanding that such changes and modifications may be made therein `as fall within the scope of the appended claims without departing from the spirit of the invention.

In said drawings:

Figure l is a longitudinal, vertical section through a switch constructed in accordance with the present invention taken on line 1--1 of Figure 2 looking in the direction of the arrows;

l- Figure 2 is a horizontal section through the switch tak- Patented Sept. 8, 1959 ice en on line 2-2 of Figure l looking in the direction of the arrows;

Figure 3 is a transverse central section taken on line 3--3 of Figure 2;

Figure 4 is a bottom plan view of the switch operator shown in the central or neutral position, the contact-carrying springs being sketched in position to illustrate their cooperative position relative to the expanding and compressing elements on the operator;

Figure 5 is an end elevation of the switch operator removed from the housing;

Figure 6 is a fragmentary central longitudinal section through the switch operator, on an enlarged scale, showing its cooperation with the resilient, double-function bumper block;

Figure 7 is a perspective view of the rubber bumper block;

Figure 8 is a fragmentary plan view of the switch housing arranged for single pole, double throw operation; and

Figure 9 is a View similar to Figure 8 showing a single Y pole, single throw construction.

One of the advantages of switches designed for use with alternating current only, is that they can satisfactorily break reasonably large currents, even when supplied to inductive circuits, without destructive arcing due to the self-quenching effect of the current passing through zero and hence they can be of the non-snap variety, materially simplifying their construction and reducing the noise of operation. All of these advantages are valuable in small switches used for household lighting circuits and the like, but have been ditlicult to achieve in switches of various small sizes because of operating problems and restriction in the length of the spring on which the contacts are mounted. Furthermore, no satisfactory means has been provided for insuring positive operation of the spring and its contact both on the make and the break, particularly in connection with double acting switches and such switches handling both sides of a two line circuit where the operator is the usual ilip lever and the body is very shallow.

In A.C. switches of the common snap-switch contiguration and size adapted for use three in a single gang box, developments have been largely along the line in which the springs extend vertically upwardly from the bottom of the switch housing and are thus seriously limited in length, or in which, while extending longitudinally of the housing, have their planes parallel to the housing bottom, offering diiculty in operation except where a simple cam is used capable of controlling the motion of the spring in one direction only. Positive control is highly desirable in both directions for obvious reasons, and in the construction proposed in this application, difculties heretofore experienced are overcome by arranging the springs not only longitudinally of the housing but with their planes parallel to each other and to the side walls of the housing, thereby achieving more nearly maximum length and enabling them to cooperate conveniently with the customary switch operator of the tumbler type found most acceptable for household use, while at the same time making for a shallow body.

The resulting switch is capable of being made up in a number of forms from a simple single-pole make-andbreak type through the single pole three-way, double-pole reversing or so-called four-way, double-pole single-throw and others by simple rearrangement or omission of stationary contacts and contact-carrying springs.

Referring now to the drawings for a better understanding of the invention, and rst to Figures l and 2, showing the most complex form of the invention, the switch is assembled in a housing 12 generally rectangular in plan and elevation and having a flat closed bottom 14, substantially at end walls 15 and 16, and au open top 174 D which is adapted to be closed by a cover 18 secured thereto in any desired manner, as by the mounting strap, not shown. Since switches of this invention are capable of being ganged as many as three to a normal single gang boxv andarrangedl side by side, the side walls offthe housing are iiat as shown at 17 so as to admit of-clse assembly.

As seen kin both`Figures 1 and 2, the housing is-iittedV at each end with a pair of terminal platesnumbered respectively 2t), 21, 22 and 23 which are introduced through the open top of theV housing before the terminal screws 24 are attached thereto and rest against the upper faceA of the bottom wall 14 and-are positioned by slotsY such as 25 in the side walls-and abutments as 26 behind` which the inner edges are engaged, separated and insulated. Appropiiately rivetedror otherwise secured near theV upper ends of the plates-Ztiand 21 are the-right-angled ends 27 and 2S of'contact springs wand-30, respectively. TheseY springs extend generally longitudinally of the housing,

and in the so-called four-way switch illustrated in Figures 1 and 2, are each fitted at their remote ends near' the opposite end wall witha pair of contact buttons .30 and 3l for- spring 29, and 32 and 33 for spring 30. These face in opposite directions and are in transverse alignment on the springs. They are adapted to selectively engage between pairs of stationary contacts 31%, 3S', 36, 37, respec tively, under the action of an operator, whichbrings-bothV springs to the position illustrated` in FigureZ, where contacts 31 and 35 and 32 and 36 engage each other, or to a spread position, where contact 31) engages contact 34,

and contact 33 engages contact 37. Stationary contacts'- 35 and 37 are both mechanically mounted on and electrically connected to terminal plate 23, while stationary contacts 34 and 3:6 are similarly connected to and supported from terminal plate 22.

Under theA circumstances just described, the switch is a true four-way switch, for in the position illustrated, the terminal plate 29 is connected through to terminal plateA 23 while Z1 is connected to 22. When the spring contacts areV spread, terminal plate 2,6 is connected to terminal plate 22 and 21 to 23.

The method of securing the stationary contacts to their respective plates forms a lessV important feature of the invention and need be described only generally. Thus it will be seen that the outside stationary contacts 34 and 37 are respectively mounted on right-angled extensions 4t) and t1 integral with plates 22 and 23 and the inner ends of these extensions are supported between upstanding studs 42 and 43 respectively, molded as integral portions of the housing, and the respective outer walls thereof along the reinforcing ribs shown.

The terminal plates 2@ and 21 likewise haveright-angled extensions 46 and 47 respectively which engage along the side walls of the housing and stabilize the terminal plates and their springs Z9 and 30. These springs are shown also as having portions adjacent the right-angled ends 27 and 28 abutting against the end walls of column 26. Thus both the contact sets mounted on the springs and those carried by the terminal plates 22 and 23 are supported from rigid fixed anchorages and the stationary contacts themselves are held against movement under the impact of the contacts on the ends of the springs to insure against rebound. In this respect, it may be noted that the crossed connecting plates 50 and 51 respectively connecting terminal plate 23 to stationary contact 35 and terminal plate 22 to stationary contact 36 may be sufciently ilexed during assembly to insure rigidity of the stationary contacts by having their ends 52 and 54 stressed against posts 55 and 56 to insure a rigid mounting.

The pairs of posts 42, 55 and 43, 56, respectively, are

seen in Figure 3 to border the shallow notches 58 and 60v in which springs 219 and 30 respectively move laterally on being flexed from one contact position to another. The at bottom walls of these notches, clearly visible in Figure 3J prevent any tendency for sagging 011A the. Part Qi the contact springs under the action of the spring operator later to be-described. Likewise, the anchor ends of the springs 29 and 30 are supported on the top surfaces of the respective lugs 6d and 61, Figure 2, the latter of which is also seen in Figure 1.

The side walls 17 of the housing have their inner faces centrally notched at the upper edge thereof as seen at 63 and 64 to form half bearingsfor the trunnions 65 and 66 integraliwith the switch operator as seen in Figures 1, 4, 5 and 6, as well as in section Figure V3. The cover plate 13 has complementary notches 67 and 68 so that when assembled as shown in Figure 3, the trunnions are adequately restrained but permit oscillatory motion of the handle 70A from the position shown in Figure l to a corresponding position to the left thereof in the normal manner of the usual toggle switch handle. An appropriate cut-out 71 in the cover 18 permits the respective wings 72 and 73, as well as the handle, to pass in and out of the housing to present to the operatorindicia 74- on the upper face of one wing or the other, dependent on the position of the handle. Such indicia may, in the single pole switch, be either On"7 or Off.

Extending downwardly from the under side of the tumbler assembly and in alignment with the handle is the stud-like element Sd having its lower end reduced in diameter rounded as shown at Sl to lit in the upper end of the open coil helical spring S2, the lower end of which engages over a similar stud-like member 83 extending upwardly from the bottom wall 14 of the housing. v With the spring normally compressed between members 81 and @3, Yit will be seen that there are only two positions of stability for the handle, one shown in Figure l and the second in a corresponding positionY to the left, and these are achieved by means for stopping the handle in these two selected terminal positions. in the present instance, such stop means comprises a single block of resilient material such as natural' or synthetic rubber, such block being shown at 84 in Figure 7 in perspective and comprises a cylindrical portion S5 having an enlarged disk-like head 86 and a radialY wing 87 having flaring sides S3 where it leads off from the cylindrical portion S5 and parallel sides, as well asA a flat end S9 and a hat top 9h. As best seen in Fig,- ure 2, the cylindrical portion 85 fits in a correspondingly shaped bore in the in ner extension of post 26 and the flaring portion also is received in an appropriate channel therein, the head 86 stopping against theV top wall of the post in the manner illustrated ini-Figure l. This head 36 cooperates with the undersurface 91 of the Wing 73 as seen in Figure l, stopping motion to the right as illustrated. When the switch handle is moved to the opposite position, such as illustrated in Figure 6,v a rib 52;V on the side ofk the depending, spring-engaging stem 3 9 presents al corner 93 which engages the Yend face 8S ofthe widened unencased portion of the'rubber bumper and limits movement of the handle to ther left. rlvhrus, one single rubber bumper element, comprisesa unitary molded construction as seen in Figure 7, acts to stop movement or" the handle in either direction and Ybecause of its resilience silences the action resulting from the over-center spring so that with careful useuthe switch cannot be heard. Because there is no snap action, nothing but the handle needs be stopped, for the spring only determines the handle position and does not operate to move a contact-carrying cradle independently of the handle as inthe conventional snap-switch.

For the purpose of simultaneously moving the two springs 2,9L and 309, either to the inner engaged position illustrated in Figure 2, or the opposite position when they are spread to engage the outer stationary contacts 34 and 37, the undersurface of the tumbler element is given a peculiar configuration. Viewing it in Figure 4, with the handle element assumed to be vertical and the springs in the neutral position, there will be seen a large trianmllar 1ug95 spaced just to the left of the center stud 80, having its base lying normal to the axis of oscillation of the handle element and its point extending to the left. To the right of the stud 80 and spaced apart transversely substantially less than the width of the base of triangle 9S are the parallel wings 96 extending to the outer end of wing portion 73. They stop as far to the right of stud 80 as the base of the triangle 9S is to the left and these end edges are numbered 97 and merge with rounded fillets with the inner faces of the wing parts 96. Also shown in this view are the springs in their most relaxed position, where it will be clear that they simultaneously engage both the tips 100 of the triangularlug and the rounded edges of wings 96. This is, however, not a continuous condition from one end of the handle throw to the other but a transition state to insure that movement induced by spring 82 cannot cause the operating lugs to slap against the spring arms and create a noise. In the center position shown, the principal engagement of the springs is being transferred from one set of lugs to the other but no noise results. The peculiar shape of the springs and lugs is eiective to insure constant contact of each spring and one or the other of its lugs at all times.

Viewing the springs in Figure 4, it will be seen that the right-hand portions thereof are straight and parallel to the iniiection points 98 and that they are spaced closer together than the inner faces of the wings 96 to clear them. At 9S begin the straight portions 99 which ilare as seenin Figure 4 to maintain contact with the fillets at the corners of the wings 96 and to lightly engage the tips 100 of the triangle 95 when the handle is in the central position. These straight inclined sections 99 extend to a position somewhat to the left of the triangle tips 100 and there merge with the parallel end sections 101 of the springs which carry the dual contact buttons previously referred to, through the agency of outwardly aring bights 102 which serve to avoid contact with tips 100 when the springs are in the position shown in Figure 2.

It will be seen from Figure l that when the handle 7i? is moved to the right to move the illeted noses of the wings 96 along the inclined sections 99, whereby to draw the spring ends 101 together to engage the inner stationary contacts, the triangular lug 95 moves to the left but has no contact with the spring parts 99. When reaching a nal position adjacent the loops or bights 192 the clearance is greater which insure the springs clearing the outer corners 100 of the triangle just as they are being brought into contact with the inner contact buttons. This action is fairly well illustrated in Figure 2 where the inner corners of wings 96 are shown in close engagement with the now partially straightened portions 99 of the springs, holding the contact buttons 31 and 32 in close engagement with stationary buttons 3S and 36 respectively.

ln a somewhat like manner, when the switch handle 70 is thrown to the left, the wings 96 are moved along the springs well to theright in Figure 4 so as not to interfere with their spreading under the action of movement of the tips 100 of the triangular operating lobe 95 which engage the inner faces of the sloping portions 99 and force the springs apart until their contact buttons 30 and 33 engage the outer stationary contact buttons 34 and 37 respectively. The switch handle being held in either of its maximum positions by its spring 80 acting with maximum effectiveness insures the tight engagement of either set of contacts on the springs with the corresponding stationary ones. By the use of two sets of operators, the springs are positively engaged and disengaged in both directions and there is no opportunity for failure to operate by sticking of the contacts due to welding resulting from heavy current. This results from the fact that either operator for the springs must rst 6 separate the engaged contacts before closing the other set.

The switch illustrated in Figures 1 to 7 inclusive is the most complex of those which can be fitted into the disclosed housing.

In the construction illustrated fragmentarily in Figure 8, by omitting the spring numbered 30 in Figure 2 and the stationary contacts with which it engages, a single pole socalled three-way switch is provided whereby one of the oppositely facing contacts on the spring may engage either one of stationary contacts 34 or 35 carried respectively by terminal plates 22 and 23 mounted exactly as those illustrated in Figure 2.

For further simplicity, a single pole switch is illustrated in Figure 9 and in this view the contact button 35 and its supporting plate 23' have also been omitted. Either a blank plate may fill the position intended to be occupied by plate 23 or the housing may be molded without the opening permitting access to this position.

Normally the same handle and actuators would be used for all styles of switches but when using a single spring these can be simpler, it only being necessary that the operating edges of lugs 96 and 100 have an overlapping relationship laterally to act on the inclined section of the spring for fast make and break.

On the other hand, as will be obvious, the inner stationary contacts 35 and 36, of Figure 2, and their supporting arms 50 and 51 may be omitted, thus providing a double pole single throw switch, useful and required in many situations.

Other possible combinations are obvious and need not be detailed here. Any of the types of switches arranged in the housing shown represents the minimum in number of parts to achieve the results desired. The construction can readily be modified for large scale production of single pole switches to reduce the size of some of the moulded parts.

I claim as my invention and desire to protect by United States Letters Patent the following:

1. An A.C. switch for use behind a wall plate and having in combination; an insulating housing having closed sides and bottom, ends mounting terminal plates, and a removable cover; a at spring extending substantially the length of the housing in a plane normal to said bottom and having one end secured to a terminal plate, a stationary contact carried by a terminal plate at the opposite end of the housing and extending to cooperate with the free end of said spring, the ends of said spring lying in substantially parallel but laterally offset planes and being connected by an intermediate section inclined to said planes; an operating and handle unit for said spring having trunnions pivoted transversely of said housing between the central upper edges thereof and the cover, said handle extending through an opening in said cover, a stud coaxial to said handle and oppositely extended and a stud in the center of said bottom; an over-center spring compressed between said studs to hold said unit in either of its stroke-end positions; a pair of projections from said operating unit spaced apart along and adapted to straddle said intermediate section of the hat spring in all ranges of movement of the handle, the spring engaging projections being laterally offset transverse to their planes of movement so as to have an overlapping relationship whereby they act on said inclined section of the spring to provide fast contact make and break, and said projections being of such shape as to provide continuous projection engagement of the hat spring to inhibit unrestrained movement of the operating unit under the action of said over-center spring.

2. The A.C. switch of claim l in which said spring is normally set to assume a position intermediate said On and Oif positions when the handle is centered.

3. The switch as dened in claim l wherein a second ilat spring is arranged adjacent the first, is mounted on an electrically separate terminal plate and cooperates with an electrically separate stationary contact mounted on a separate terminal plate, said projections from the operating unit being arranged to separately straddle both springs to move them simultaneously and positively in opposite directions to both make or both break contact, and said intermediate sections of the two springs are oppositely inclined whereby a single projection may act to spread them simultaneously.

4. The switch as defined in claim 3 in which each flat spring is arranged to engage a tixed contact in each of its two extreme positions and means extending integrally from the contact carrying terminal plates connecting each contact which is adapted to be engaged by a spring when the springs are spread to the one adapted to be engaged by the other spring when the springs are moved toward each other and in which the adjacent facing stationary contacts for alternate engagement by one spring are separated by an abutment integral with the housing.

5. The switch as defined in claim 4 in which the remote fixed contacts are engaged against the outer walls of the housing while connected to and supported by said end wall terminal plates.

6. The switch as defined in claim 1 in which the junction between the contact end of the spring and said intermediate section is a bight with its concave face directed toward the said projection on the operating unit which is closer to the free end of the spring and said projection having a narrow wedge-like operating surface adapted to be cleared by said bight when the projection is at the end of its stroke toward the contact on the end of the spring whereby the more remote projection is fully in control of the spring.

7. The switch as dened in claim 1 in which said flat spring extends through a notch in an interior wall of the housing and ycooperates with the bottom thereof to prevent displacement by the action of the abutments travelling in arcuate paths along the spring faces.

8. In an A.C. switch of the type described, in combination, an insulating housing adapted to be mounted beneath a wall plate and having closed sides and bottom, a pair of hat springs extending longitudinally in said housing with their planes normal to said bottom, spaced mounting and terminal plates for one end of each spring in one end wall of said housing at least one contact for 'engagement by the free end of each spring near the opposite end of said housing, spaced mounting and terminal plates for said contacts in the opposite end wall, an operator fulcrumed in said housing for movement in a plane roughly parallel to said springs, having a handle extending out of said housing and means projecting into the housing to straddle each spring separately, each spring having a contact element at the free end and an intermediate portion inclined to offset the ends thereof laterally with the contacting ends of the two spring more widely separated than their mounting ends, said means projecting into the housing to straddle the springs separately being spaced apart on the operator and arranged to successively engage said inclined intermediate portion of each spring at longitudinally spaced positions thereon, one on one face and the other on the opposite face, whereby the contact end of each spring is continuously controlled and positively and selectively urged in either e: direction to engage or disengage a `stationary Contact, said projecting means including a lug between the springs having laterally spaced operating edges and two lugs outside of said springs, said lugs being nearer the mounting ends and having operating edges closer together than those on the rst lug.

9. An A.C. switch of the type described having in combination; a stationary contact, an elongated flat spring anchored at one end and having a contact at the other end thereof for cooperation with the stationary contact, an operator for said spring pivoted on an axis normal to the general plane of the spring and having a handle adapted for arcuate movement in said plane and a pair of lugs opposite the handle from said axis, said lugs straddling said spring, being spaced apart along its length and each having a surface for contact with the corresponding face of said spring vfor moving the same laterally, said spring having a substantially straight section adjacent the anchor and a second contiguous straight section, the planes of the two sections being inclined to each other with an included angle of the order of degrees, the junction of said sections being so located and the said contacting surfaces on the lugs so spaced that each of the latter is successively in contact with the corresponding spring face throughout approximately one half of its stroke, the lug edge closer to the spring anchor being positioned on the included angle side of the spring and said lugs having an overlapping relationship laterally of their paths of movement.

10. In an AC. switch of the type described, in combination, `an insulating housing having closed sides and bottom, a terminal plate for and partially closing each end of the housing, a at spring extending longitudinally in the housing from one of said plates with its plane normai to said bottom, an intermediate portion of said spring being inclined to offset the end parts thereof, a contact carried by the other plate and positioned to be engaged by the free end of said spring, an operator carried by said housing for limited stroke movement in the direction of the spring length, means on said operator projecting into the housing to continuously engage at least one of the opposite faces of said spring at and adjacent said inclined portion and at longitudinally spaced positions on the spring to positively and selectively urge and hold the spring in a direction to engage or to disengage the stationary contact in accordance with the direction of movement of said operator, the means on said operator having acting edges laterally disposed and longitudinally spaced along the spring, said edges being offset oppositely to the spring ends.

References Cited in the file of this patent UNlTED STATES PATENTS 1,938,721 Rhodes Dec. l2, 1933 2,411,086 Farmer et al. V Nov. 12, 1946 2,553,188 McWilliams lune 26, 1951 2,648,731 Despard Aug. l1, 1953 2,669,613 Despard Feb. 16, 1954 2,763,739 Forstrom Sept. 1S, 1956 2,807,683 Bettencourt Sept. 24, 1957

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