US3182161A - Handle quieting action for a. c. switches - Google Patents

Description

May 4, 1965 P. H. WINTER HANDLE QUIETING ACTION FOR A.C. SWITCHES Filed Oct. 16, 1961 INVENT OR PAUL H. WINTER BY fax. l A'ITORNEE United States Patent M York Filed Oct. 16, 1961, Ser. No. 145,082 6 Claims. (Cl. 200-168) This invention relates to switches and more particularly to alternating current type switches having a socalled tumbler mechanism, and deals primarily with improvements in the contact arrangements therefor and in means for quieting the operation.

It is a general object of the present invention to provide a novel and improved A.C. tumbler switch with quiet action.

More particularly, it is an object of the invention to provide a switch body of cup-like form molded of insulating material with an open top, having a one-piece handle-operator arrangement with integral trunnions journalled in notches in the side walls of the cup and held in position by means of a cover of resilient sheet material secured down to the top edges of the cup and flexed in areas by means of lobes adjacent the trunnions, whereby frictional resistance to movement of the handleoperator unit is continuously provided to slow down its action under the urge of an over-center spring which biases the handle-operator in either direction after it is initially moved from a dead-center position, whereby the switch is quiet in both the opening and closing actions.

Another object of the invention comprises the use of an insulating cup open at the top and having spaced parallel sides each supporting a terminal plate having a contact arm projecting toward and overlapping but spaced from the arm on the other plate, together with a handleoperator mechanism for moving one of the arms into engagement with the other or separating it therefrom under the. action of an over-center spring.

One of the important features of the invention resides in the provision of lobes, of concentric form on the trunnions and adjacent thehandle, which project above the trunnion circumference in the same direction as the handle, whereby when the trunnions are journalled in notches in the side walls of the insulating cup to the depth of their diameter these lobes extend above the top surface of the cup and may be engaged by a resilient cover plate which is pressed down against the top surface of the cup and thus is tensioned against the lobes which thereby provide friction to slow the movement of the handle to thus quiet the action of the switch. This insulating cover plate is required to close the insulating cup, retain the contacts in position and hold the handle trunnions in their notches and thereby has multiple functions. 7

Another feature includes in switch structure, having a handle-operator with trunnions fulcrumed in the edges of an insulating cup, the use of a plastic or vulcanized fiber insulating cover sheet held down peripherally against the edges of the cup and not only serving to close and insulate the cup and contents but also to retain the trunnions in their slots. It has narrow strips severed on the edges only of the handle opening from the remainder of the sheet for bearing on friction lobes on the trunnions to slow the switch action.

Other and further objects and features of the invention will be more apparent to those skilled in the art upon a consideration of the accompanying drawing and following specification wherein is disclosed the single exemplary embodiment of the invention with the understanding that such changes and modifications may be ever it is released thus insuring good contact.

Biddbi Patented May 4, 1965 made therein as fall within the scope of the appended claims without departing from the spirit of the invention.

In said drawings:

FIGURE 1 is a top plan view of the assembled switch, the handle being in the central or dead-center position for convenience in illustration;

FIGURE 2 is a view similar to FIGURE 1 with the mounting strap and cover holding frame unit removed;

FIGURE 3 is a side elevation of a threeway switch constructed in accordance with the present invention;

FIGURE 4 is a top plan view of the cup or housing for the switch with the mounting strap, cover and handleoperator unit removed, illustrating the construction of the contacts and their mounting in a three-way switch; and

FIGURE 5 is a longitudinal vertical section through the switch taken on lines 55 of FIGURE 1 and showing all of the operating features of the invention.

The present-day demand for household and oflice use of quiet switches of the type commonly called tumbler or Wall switches has been materially helped with the advent of full alternating current power systems since alternating current switches can be of the non-snap type and thus need not have an operating part actuated through an over-center spring from a handle independent thereof except throughthis spring connection whereby when the spring is brought to dead-center by the handle the operating part moves with a snap independent of what happens to the handle. Fortunately alternating current switches can be opened and closed slowly without arcing, because of the interruption of the current and, hence, thequenching of any spark or are which may be drawn when the current passes through the zero portion of its cycle. This not only simplifies the requirements for operating structure by eliminating the snap mechanism, but, permits the operator to quiet the switch by slowing the movement of the handle to prevent it or the moving contact banging against any stops which may be present in the construction. The operating mechanism must still, however, have an over-center spring to insure full movement of the mechanism, to on or off position when- However, if the operator releases the handle before its movement is terminated by engagement of the contacts or with a stop, considerable noise may result because of the speed of movement of the handle and associated parts under the action of the over-center spring.

Referring now to the drawings, the switch is for convenience illustrated in the form of a so-called'wall switch,

adapted to be mounted in a switch box and covered with 'a plate substantially flush with the wall surface vthrough which the operating handle 10 projects for manual movement to turn the switch on or off. The

switch is built up about a unitary cup 12 molded of some suitable insulating material, such as a thermo-settingplastic, to a rectangular form having parallel side walls 14 and 15, end walls 16 and 17 and a closed fiat bottom 18, the open top having a plane border or periphery 20 so that it may readily accept the hat cover sheet 21, preferably formed from a resilient insulating material such as vulcanized fiber or the like of similar shape, as seen in FIGURE 2, and having a central, substantially rectangular aperture 22 for the free passage of the handle 10.

As seen in FIGURES 4 and 5 the side wall 14 has secured against it and positioned by means of notches and the like a terminal plate 25 overlying the fiat rectangular base 26 of springy conducting material having an integral arm 27 bent at right angles from the right edge thereof and extending across toward the opposite cup wall 15 and preferably bearing adjacent its remote end contact buttons 28 on both faces thereof, positioned, in the three-way switch illustrated, midway between and separated from contact buttons 29 and 30 mounted on short rigid arms 31 and 32 secured respectively to plates 33 and 34 constituting terminals as seen in FIGURE 3 where they are shown fitted with terminal screws 35. These plates, like plate 25, are appropriately held in position by fitting in grooves in the walls and bottom of the housing and extending up to be engaged by the cover plate 21. Their arms are fitted against lugs 37 integral with the cup bottom, which support and help position the contacts 29 and 30 sufficiently far apart so that neither touches the contacts 28 when the spring 27 carrying the latter is in its central position as shown in FIG- URES 4 and 5. They also assist in holding the plates 33 and 34 in position.

It will be noted in FIGURE 4 that the upper edge of the spring arm 27 is slightly deformed as at 49 the better to fill up the gap 39 between actuating lug 41 extending downwardly from the under surface of the handle operator unit and the second lug 42 depending from one of the wings 43 of the handle rocker unit. These two lugs 41 and 42 straddle the spring intermediate its ends and somewhat closer to the plate end of the spring than the free end. The width of the gap, Without the Spring deformation might allow contact engagement at mid-position of the handle under some conditions.

The handle operator unit is an integral molding of plastic insulating material and includes a pair of opposed trunnions 45 and 46 extending transversely from it and forming the axis of rocking thereof and adapted to have their ends received in notches 47 and 48 in side walls 14 and 15, respectively, which notches are of a depth just about equivalent to the diameter of the trunnions. They have straight side walls to facilitate inserting the rocker from the top.

Portions of the longer edges of the cover plate or sheet 21 overlie the ends of the trunnions and hold them loosely in position in their notches. The lug 41 which acts to move the spring in one direction is formed integral with a large lug 49 having at 50 a tapered tip which opposes, when in the central position, a corresponding nub 51 extending up from and integral with the bottom wall of the cup whereby an interposed helical spring 52 which may be termed an over-center spring will urge the handle operator assembly into either of its maximum positions, where one lug or the other pushes spring 27 and its contact against one of the stationary contacts and holds it there for excellent electrical conductivity.

It will be seen that with the over-center spring, should the handle be moved slightly beyond the center position shown in FIGURE and then released, the handleoperator will be snapped over until the appropriate set of contacts is engaged, and, unless restrained the velocity of movement of the handle would increase rapidly after release so that there would be quite a noise resulting from the sharp engagement of the contacts. This can be prevented if the operator will hold onto the handle and slow it, but usually such handle is merely flipped by a throw of the finger or thumb and quite a noise ensues.

It is therefore the intent of the present invention to provide means to slow up the motion of the handle unit and this is achieved by providing on the upper surface of each trunnion, inwardly from its end and preferably against the handle portion, a concentric lobe 55 which extends in the direction of the handle, or upwardly from the trunnion portion, a sufiicient distance to engage strongly against the undersurface of the insulation cover 21 for the switch cup. In order that this portion of the cover may yield without distorting the whole cover, slots 60 are cut longitudinally in the cover as best seen in FIGURES 1 and 2 leaving the narrow intervening strips 61, between these slots and the widened center portion of handle aperture 22. Thus, when the cover is placed in position, and the metal frame 64 clamped in position over it to hold its periphery tightly against the plane surface 20 surrounding the upper edge of the cup, the strips 61 are bowed upwardly providing a yielding frictional engagement with the lobes on the rocker assembly throughout its whole stroke from one end to the other whereby its rate of movement under the action of its over-center spring is materially slowed down and any noise resulting from engagement of the contacts or of any other stop means substantially reduced in volume.

The frame 64 is of conventional construction except that its side members 65 are narrowed as a result of widening the opening which surrounds the handle, to thus prevent any pressure on the surfaces of the strips 61 which might prevent them from bowing upwardly under the pressure of the lobes. The frame including side members 65 and end members 66 is provided with extensions 67 in order to form a mounting strap should the switch be intended for use in a wall box. Otherwise it may be designed for mounting on the conventional Despard Line strap. The metal frame has integral tongues 68 which were initially parallel to but separated from the extensions 67 and which are bent downwardly at right angles to engage against the end walls of the cup and are then bent toward each other and beneath the extension lugs 69 on these end walls. The ends are shown at 70 curled beneath these lugs to hold the frame tightly in position and the switch completely assembled.

A consideration of FIGURES 3 and 5 will illustrate the manner in which strip 61 on either side of the handle is bowed upwardly under the action of its lobe 55 arranged on each trunnion betwen its outer bearing end 45 and the handle portion 10. As seen in these figures, this strip 61 is substantially deflected and stressed out of the normal plane of the cover plate 21, so that pressure is applied vertically and radially toward the axis of the trunnion not only increasing the friction of the bearing end thereof in the bottom of notches 47, 48, but there is considerable rubbing friction between the arcuate surfaces of the lobes 55 and the undersurfaces of the strips 61. These combined frictions occurring on both sides of the handle are sufficient to retard the motion of the handle operator, yet insufiicient to stop complete movement under the action of the over-center spring 52. This insures completion of each stroke although the handle may be released shortly after passing the deadcenter position but the continued motion from there on is at a reduced speed due to the friction so that any impact between the contacts is lessened in intensity and, hence, the sound resulting therefrom is of minor consequence.

It should be understood that the insulating cover plate 21 performs multiple functions, first as a closure for the cup and to insulate the contents thereof from the frame 64, second, to hold the handle-unit trunnions in their notches, third, to secure the contact spring and the contact terminal plate in the cup grooves, and finally, with no additional parts or materials, provides effective retardation to the handle unit to quiet its operation.

It will be appreciated that while the drawings illustrate an embodiment using two stationary contacts to form what is called in the industry a three-way switch, one of the stationary contacts can be eliminated to form an ordinary single-pole switch. Not previously mentioned is the fact that the terminal plate 25 through which connection is made to the contact plate 26 and, hence, plate 26 supporting spring 27 is exposed through a notch in the wall 14 to receive a terminal screw in the same manner as are the plates 33 and 34 in the respective notches 72 seen in FIGURE 3. In the construction illustrated there is no stop provided for the stroke of the handle operator in either direction, reliance being placed on the engagement of the movable contact with one of the stationary contacts for this purpose thus insuring adequate electrical conductivity since the contacts are continuously held in position against each other by the action of the over-center spring 52. If one stationary contact is omitted some equivalent stopping means, preferably of non-conducting material, must be substituted for it, such as a projection integral with the housing to limit movement in the ofi' position.

What is claimed as new and desired to be secured by Letters Patent is:

1. In anelectric switch, in combination, an insulating housing having an open front, contacts and terminal plates in said housing, side walls on said housing having opposed bearing notches in their forward edges, an oscillatable switch operating lever having a handle portion and laterally disposed oppositely directed trunnions extending therefrom, bearing ends on said trunnions journalled in said notches and substantially tangent to said edges, an overcenter spring between said lever and housing, a lobe on each trunnion between its bearing end and the lever and oriented in the radial direction of said handle, a cover for closing said open front sized to bear on said side Walls and said terminal plates to hold the latter in position and having an elongated central opening therein for handle movement, said cover being of thin resilient insulating material and having a narrow slit on each side of said opening parallel to the adjacent side wall and substantially over its inner surface, said trunnion lobes engaging beneath and flexing the cover strips between the slits and opening to retard lever movement, and a rigid metal frame engaging the peripheral portions of said cover above said walls and said terminal plates to secure it to said housing and insulated by it from said contacts and terminal plates.

2. In an electric switch, in combination, a cup-like housing of insulating material, an operating lever for said switch having a handle and laterally and oppositely disposed trunnions having bearing ends, bearing notches in opposite walls of said cup extending from the outer edges thereof for the full depth of said bearing ends, an overcenter spring egaging the lever and housing to urge the lever to either end of its stroke when it is moved over center, a fiat cover of flexible sheet insulating material engaging said outer edges and holding said ends in the notches, means engaging its periphery and securing said cover to said cup, a rectangular hole in said cover to pass the said handle for movement therein, lobe means on said trunnions intermediate said ends shaped to engage the underside of said cover adjacent said hole to flex it there out of its plane to apply pressure to said trunnions and hence resistance to lever movement to quiet the switch operation, and a slot in said cover sheet spaced from each longitudinal edge of said hole to define with the latter a narrow strip attached by its ends only to the cover and positioned to be engaged by said lobes.

3. In an electric switch in combination, a cup-like housing of insulating material, means resiliently supporting contacts for circuit control in said housing, an oscillatable operating lever for said switch including a handle portion with opposite laterally disposed extensions therefrom having bearing end trunnions, and a spring arm and actuating mechanism for moving said contacts disposed opposite the handle, bearing notches in opposite walls of said cup journalling said bearing end trunnions, a flat cover of flexible, resilient insulating material engaging the rim of the housing and having a hole for handle movement, conductive frame means securing the cover periphery to the cup to close it, a compression spring between said spring arm and the bottom of said cup to move the lever and hold it in its extreme positions to press said contacts together, and means eccentrically positioned on said trunnions and continuously engaging the underside of said cover adjacent said hole to flex portions of the cover out of its fiat condition to exert frictional resistance to movement of the lever to quiet its action by slowing its movement under the action of said spring, said cover portions lying alongside of said hole and being severed from the remainder of the cover except at their ends.

4. In an electric switch in combination, a cup-like housing of insulating material, an oscillatable operating lever for said switch including a handle portion with opposite laterally disposed trunnions projecting therefrom having bearing ends, and a spring arm and actuating mechanism disposed opposite the handle, bearing notches in opposite walls of said cup journalling said bearing ends, a flat cover of flexible resilient insulating material engaging the rim of the housing and having a hole for handle movement, means securing the cover to the cup periphery to close it, an over-center compression spring between said spring arm and the bottom of said cup to move the lever and hold it in either of its extreme positions, said cover engaging and holding the said bearing ends in their notches, lobe means on said trunnion extensions between said handle and bearing ends extending into engagement with the underside of said cover, and slots in said cover parallel to the plane of movement of said handle and lying one between each bearing end and said lobe means on the adjacent trunnion to release the sides of a strip of cover extending alongside of said handle hole whereby it is bowed outwardly by said lobe means engagement to supply friction to retard handle movement under the urge of said spring and thereby quiet switch operation.

5. In an electric switch for alternating current in combination, a cup-like housing of insulating material generally rectangular in plan having end and side walls and a bottom wall, a terminal plate on one side wall, a flat spring cantilevered from said plate toward the opposite wall, a second terminal plate on the opposite wall having a contact area projecting in overlapping relationship to the end portion of said spring for contact thereby on spring flexing, an operating lever for said switch having a handle, an oppositely directed spring post, and, a pair of aligned laterally disposed trunnions each with a bearing end and an arcuate area of greater radius than said bearing end oriented toward said handle and between it and the bearing end, bearing notches for said bearing ends in the upper edges of said side Walls of a depth equal to hearing end diameter, a flat cover of flexible sheet insulating material sized to cover the upper edges of said walls and close the cup and hold said terminal plates therein by engaging their outer edges, an opening in said cover for handle passage and oscillation, a slit in said cover adjacent each of two opposite edges of said opening and extending in the direction of movement of said arcuate areas to define end attached cover strips, a helical expansion spring interposed between said spring post and the cup bottom to provide over-center movement for the lever, a pair of lugs on said lever below said trunnions spaced to straddle said cantilevered spring to urge it into or out of engagement with said contact area under the action of said helical spring, and means holding the said flexible sheet against the cup edges to flex said cover strips over and against said trunnion arcuate areas to retard operating lever movement under the urge of said expansion spring.

6. The combination in an electric switch of an insulating cup of rectangular plan having an open top with a plane border, opposite side walls of said cup, each supporting a terminal plate exposed on the outer side thereof, a short rigid conducting arm extending toward the opposite wall from one of said plates, a resilient conducting arm of greater length extending from the other plate in overlapping but spaced relation to the first arm, a lever having trunnions fulcrumed for limited rocking in notches in said side Walls as deep as their diameter on an axis substantially parallel to said second arm and having a handle extending outward through said open top, the inner end of said lever having spaced lugs straddling said longer arm and adapted to move it positively into and out of contact with the first arm as the handle is rocked, overcenter spring means interposed between the inner end of said lever and the cup bottom to hold the lever iin contact closed or open condition, a cover for said cup formed of resilient sheet material having an opening to pass said handle, open frame means securing said cover against said border, and lobe means rockable with said handle engaging the undersur-face of said sheet in an area within said frame to flex the area outward to offer frictional resistance to handle movement, said area being integral with said cover sheet, extending in the direction of movement of said lobe means and bordering one edge of said opening for the handle, and a slit separating said area from the portion of the cover overlying the adjacent border.

8 References Cited by the Examiner UNITED STATES PATENTS 2,648,731 8/ 5 3 Despard 200-466 2,807,683 9/57 Bettencourt 200-67 2,917,610 12/59 Taylor 200-152 2,927,184 3 60 Hubbell 200-166 3,054,878 9/62 Wiley 72-00-152 FOREIGN PATENTS 91,038 12/37 Sweden.

BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner.

Claims (1)

1. 2. IN AN ELECTRIC SWITCH, IN COMBINATION, A CUP-LIKE HOUSING OF INSULATING MATERIAL, AN OPERATING LEVER FOR SAID SWITCH HAVING A HANDLE AND LATERALLY AND OPPOSITELY DISPOSED TRUNNIONS HAVING BEARING ENDS, BEARING NOTCHES IN OPPOSITE WALLS OF SAID CUP EXTENDING FROM THE OUTER EDGES THEREOF FOR THE FULL DEPTH OF SAID BEARING ENDS, AN OVERCENTER SPRING ENGAGING THE LEVER AND HOUSING TO URGE THE LEVER TO EITHER END OF ITS STROKE WHEN IT IS MOVED OVER CENTER, A FLAT COVER OF FLEXIBLE SHEET INSULATING MATERIAL ENGAGING SAID OUTER EDGES AND HOLDING SAID ENDS IN THE NOTCHES, MEANS ENGAGING ITS PERIPHERY AND SECURING SAID AND HENCE RESISTANCE TO LEVER MOVEMENT TO QUIET THE SWITCH OPERATION, AND A SLOT IN SAID COVER SHEET SPACED FROM EACH LONGITUDINAL EDGE OF SAID HOLE TO DEFINE WITH THE LATTER A NARROW STRIP ATTACHED BY ITS ENDS ONLY TO THE COVER AND POSITIONED TO BE ENGAGED BY SAID LOBES.

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