US3586796A - Electrical switch with improved common terminal housing retaining means for pivoted contact - Google Patents

Abstract

An electrical switch including an open-ended housing having a pair of terminals mounted on the base. A permuting arm is fulcrumed intermediate its ends solely on a traversely extending end on one of the terminals. The end of the terminal projects into the housing so that the permuting arm may be pivoted thereabout and a contact point on one end thereof is positioned into and out of engagement with a contact point on the other terminal. A rockable actuating button having a spring biased rod engages the permuting arm and serves to selectively pivot the permuting arm contact into and out of engagement with the terminal contact.

Description

United States Patent Appl. No.

Filed Patented Assignee ELECTRICAL SWITCH WITH IMPROVED COMMON TERMINAL HOUSING RETAINING MEANS FOR PIVOTED CONTACT 8 Claims, 6 Drawing Figs.

[15. Cl 200/6, Q12 9! Q Int. Cl I:I0 I h19/00, HOlh 21/04 Field olSenreh ..200/6, 67.7, 168 C Primary Examiner-4. R. Scott Attorney-Petherbridge, O'Neill & Lindgren ABSTRACT: An electrical switch including an open-ended housing having a pair of terminals mounted on the base. A permuting arm is fulcrumed intermediate its ends solely on a traversely extending end on one of the terminals. The end of the terminal projects into the housing so that the permuting arm may be pivoted thereabout and a contact point on one end thereof is positioned into and out of engagement with a contact point on the other terminal. A rockable actuating button having a spring biased rod engages the permuting arm and serves to selectively pivot the permuting arm contact into and out of engagement with the terminal contact.

riiiik ELECTRICAL SWITCH WITH IMPROVED COMMON TERMINAL HOUSING RETAINING MEANS FOR PIVOTED CONTACT BACKGROUND OF THE INVENTION The present invention relates to electrical switches and more particularly to a rocker arm type of switch.

Rocker-arm-type switches are commonly found in domestic and industrial appliances such as in television sets, instruments and the like and are used under conditions requiring frequent operation. These switches are characterized by a switch housing supporting a rocker arm button which engages a pivotally mounted permuting arm having a contact point engageable with a terminal contact point to energize or deenergize the circuitry of the appliance. The permuting arm is in continuous contact with one of the terminals of the switch during pivoting movement and selectively engageable with the other of the terminal contact points upon pivoting movements of the rocker arm button.

Heretofore, it has been common practice to provide means on the housing sidewall structure for pivotally supporting the permuting arm and locating the terminal which is in continuous contact with the arm in close proximity with the mounting means. In one such arrangement the housing sidewalls are formed with integral supports having open ended slots which receive pivot arms extending from the opposite sides of the permuting arm. The continuously contacting terminal is formed with open ended slot and located in abutting relationship with respect to one of the sidewall supports to accommodate one of the pivot arms and to make contact therewith. This arrangement achieves only a small area of surface contact so that during switch operation there is the possibility of arc-through or arc-over. Should these conditions occur during the frequent operation of the switch, it is obvious that the ohmic resistance would be increased and the reliability of the contacts would be adversely affected.

Moreover in the arrangement described above, close manufacturing tolerances must be held between the housing pivot arm supports and the slotted terminal end. Should these tolerances not be held, the pivoting action of the permuting arm may be affected so that proper engagement at the contact point is not achieved or the required continuous contact at the pivot is not maintained.

SUMMARY OF THE INVENTION By the present invention it is proposed to provide a new and improved switch of the foregoing type which is constructed and arranged to impart a positive contact at the switch contacts during switch operation to minimize arc-through or arcover as occurred heretofore.

It is another object to provide a switch constructed and arranged to achieve a sliding motion at the contact points during switching between the on and off" positions to maintain the contact points clean.

A further object is to provide a switch in which the permuting arm is pivotally supported so as to be in sliding continuous contact with a terminal about which the arm pivots.

A still further object is to provide a switch which is constructed and arranged so as to be capable of assembly by mass production on automatic machinery with a minimum of labor involving critical finger dexterity.

The foregoing objects are accomplished by a switch assembly having a housing and at least two terminals of which one terminal has an end extending into the housing transversely thereof and provides the sole fulcrum support on which a permuting arm pivots. A rocker arm assembly having means biasing the permuting arm into engagement with the transversely extending terminal is rockably supported on the housing and serves to pivot the permuting arm into and out of engagement with a contact point on the other terminal.

2 BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a front elevational view, partially in cross section, showing a switch assembly embodying the principles of the present invention and showing the panel in which the switch assembly is mounted in phantom.

FIG. 2 is an end view of the switch assembly.

FIG. 3 is a cross-sectional view taken generally along the lines 3-3 of FIG. 1.

FIG. 4 is a cross-sectional view taken generally along the lines 4-4 of FIG. 1.

FIG. 5 is a cross-sectional view taken generally along the lines 5-5 of FIG. 4.

FIG. 6 is a fragmentary view of a modification of the switch housing.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the Figures there is shown a panel 10 having an opening 11 in which there is mounted a switch assembly 12 embodying the structure of the present invention.

The switch assembly I2 comprises generally a rectangular housing 14, a first terminal 16, and a second terminal 17. Pivotally supported on the upper free or fulcrum end 18 of the first terminal 16 is a permuting arm [9 to one end of which there is fixed a contact point 21 which is engageable with a contact point 22 fixed to the second terminal 17. A rocker arm assembly 23 is rockably mounted on the housing I4 and includes a spring-biased rod 24 in engagement with the permuting arm 19 to pivot the latter between an on position as shown in full lines in FIG. 1 and an off position shown in phantom. While the switch is shown as an on-off switch, it is also capable by minor modifications to the structure shown of being converted to a double-pole double-throw switch as more fully to be explained hereinafter.-

The housing 14 is of rectangular cross section including a base 25, sidewalls 26-26 and end walls 27-27 and define an open ended chamber or cavity 28. The end walls 27-27 adjacent the base 25 are each formed with transversely extending mounting grooves 29. The mounting grooves 29-29 are adapted to receive spring fingers 31 fastened to the underside of the panel 10 and projecting into the opening II as shown in FIG. 1. In this manner the switch assembly 12 is releasably mounted on the panel 10. The housing I4 may be made from a suitable insulating material such as plastic or the like and formed by molding or the like.

The interior of the end walls 27-27 are formed to provide shoulders 32-32 which limit the rocking movement of the rocker arm assembly 23. Formed along the interior of each of the sidewalls is a trapezoidal shaped boss 33 having a recess 34 defined by inclined sidewalls 36-36 and a base 35.

Spaced lengthwise of base 25 are transversely extending slots 34, 38, and 39. As shown, slots 38 and 39 receive the first terminal 16 and second terminal 17, respectively, so that the switch serves as an on-off switch. To convert or modify the switch to a double-pole double-throw switch it is only necessary to insert a third terminal (not shown) into slot 37 and to remove a dummy boss 41 formed on the interior of the base 25 so that the left end of the permuting arm 19 may engage a contact point on the third terminal.

The terminals 16 and 17 are each made from electrically conductive material and may be formed by blanking or stamping from flat sheet stock. Terminal 16 includes a punched-out and bent horizontal lug 42 adjacent the upper end. The lug 42 rests on the upper surface of the base 25. Terminal [7 is bent at a right angle at the upper end 39 and provides a bent support for the contact point 22. The terminals 16 and 17 are formed with outwardly extending prongs 44 and 46 respectively which are punched out from the terminals. The prongs 44 and 46 are somewhat laterally flexible so as to be flexed into the plane of the terminals when inserted through the openings 38 and 39 and to be resiliently movable out of the plane of the terminals when clear of the openings so that the upper free edges engage the underside of the base 25. The prongs 44 and 46 and the lug 42 and bent ends 44 are vertically spaced to clamp the base therebetween thereby to fix the terminals 16 and 17 on the base 25.

As shown, the upper fulcrum end 18 of the terminal 16 is disposed above the level of the contact point 22 and above the base 35 of the recess 34 to provide an elongate transversely extending fulcrum about which the permuting arm 19 pivots. It is to be noted that the fulcrum end 18 provides sharp edges which are engageable with the underside of the permuting arm 19 during pivoting between the "on" and "off" positions. As more fully to be explained, the permuting arm is somewhat linearly movable during pivoting so that the sharp edges tend to abrade the underside of the arm 19 during the pivoting movement to maintain a low ohmic contact at the fulcrum.

Projecting from the opposite sides of the permuting arm 19 adjacent the fulcrum 18 are rectangular projections 46-46 which are accommodated within the sidewall recess 34 and serve to locate the arm 19 so that the contact points 21 and 22 engage. It is to be noted the ends of the projections 46-46 are spaced from the inclined recess sides 36 so that the arm 19 may slide lengthwise a limited amount.

The contact point 21 on the permuting arm 19 as well as the contact 22 on terminal 17 may each be formed from silver cadmium and riveted to the respective members.

The rocker arm assembly 23 includes a rocker arm button 47 made from Cycolac, a thermoplastic resin. The button 47 is substantially wing shaped and of generally hollow construction. Extending transversely from and integral with the sides of the button 47 are trunnions 49-49 which are journaled in opening 51-51 formed in the housing sidewalls 26-26. In this manner the rocker arm button 47 is rockably mounted between an "on" position shown in FIG. 1 wherein the left lower end abuts against the left shoulder 32 and an off" position clockwise therefrom, wherein the right lower end engages the right shoulder or ledge 32.

The rod 24 is made from a plastic such as nylon or the like and terminates in a spherical end 52 engaging the upper surface of the permuting arm 19. The rod 24 is slidably supported in a bore 53 formed in a boss 54 integral with the button 47. The bore 53 is disposed normal to the axis of rotation of the button 47. A compression spring 56 is disposed in the bore 53 and engages the inner end of the rod 24 to bias the latter outwardly and into firm engagement with the permuting arm 19.

To operate the switch, finger pressure is applied on one of the wings of the actuating button 47 to rock the latter about the trunnions 49. Assuming that the switch 12 is in the on" position as shown, with the permuting arm 19 fulcrumed on the fulcrum end 18 of the terminal 16 and the contact point 21 in engagement with contact point 22 of the terminal 17, the permuting arm 19 provides a bridge so that the circuit with which the switch 12 is associated is energized. In this position the spherical end 52 of the spring biased rod 24 engages the permuting arm 19 to the right of the fulcrum end and applies a force maintaining a firm electrical contact at the fulcrum end 18 and at the contact points 21 and 22. It is to be noted that the permuting arm 19 is inclined downwardly to the right so that the right edges of the projections 46-46 formed thereon are disposed in close proximity to the right sidewalls 36 of the boss recesses 34.

To turn the switch to the off position, the button 47 is rocked clockwise about the trunnions 49. During the clockwise movement, the spherical end 52 of rod 24 is initially pushed inwardly into the bore 53 against the force of the compression spring 56 until the rod 24 is located to the left of the fulcrum l8. Thereafter as the rod 24 rocks further to the left side, the spring 56 forces the rod 24 outwardly of the bore 53 to apply a downward force on the permuting arm 19 to rock the latter counterclockwise about the fulcrum end 18 to the off position shown in phantom. In this position the permuting arm contact point 21 is spaced from the contact point 22 so that the circuit is deenergized.

During the movement to the off" position the springbiased rod 24 applies a force on the permuting arm 19 along the length thereof so that the latter yields or bends slightly. This bending causes a wiping action at the contact points 21 and 22 during the switching action so that the points are maintained clean.

Moreover, as the permuting arm 19 pivots about the fulcrum end, there is also a slight lengthwise sliding movement as limited by the recess sidewalls 36. The sliding movement occurs on the edges of the fulcrum end 18 so that the underside of the permuting arm is subject to abrasion. In this manner low ohmic contact is maintained at the fulcrum end 18 at all times.

It should also be apparent that the parts of the switch are all of simple construction and require a minimum of handling or reforming to assemble. This permits the major portion of the assembly operations to be performed on automated equipment so that only a minimum of manual assembly operations are required. Obviously this feature increases the" production rate and correspondingly reduces the unit cost of the switch.

Holes may be formed on the housing 14 such as for example, holes 60 on the side of the housing (see FIG. 3), to vent the interior of the housing to exhaust any gases developed by the electrical switching action. Holes 60 also function to ventilate the interior of the housing 14 to provide cooling thereto.

FIG. 6 shows an alternative means for positioning and locking the switch housing 14A to its associated panel 10. The interior of housing 14A, not shown, is similar to housing 14; however, the ends of housing 14A each include an extension tab 61 (only one of which is shown) having a sloped contour which is insertable in the opening of panel 10 and having a surface 62 adapted to engage and lock below the panel, as is known in the art.

While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that changes in form and details may be made therein without departing from the spirit and scope of the invention.

What we claim is:

1. An electrical switch comprising an open-ended housing including a base disposed opposite said open end and opposing sidewalls, each of said sidewalls having a recess disposed therein in horizontal alignment with respect to one another, a first terminal mounted on said base intermediate the ends thereof and having an end projecting into said housing transversely of said sides, a second terminal mounted on said base and spaced lengthwise from said first terminal, a permuting arm supported intermediate the ends thereof solely on said projecting end of said first terminal for pivotal movement thereon between a position in which one end of said arm contacts said second terminal and a position spaced therefrom out of contact therewith, projections extending laterally from said permuting arm positioned for seatment within said recesses on said sidewalls, a rocker arm assembly mounted on said housing projecting through said open end and including means engageable with said permuting arm on opposite sides of said fulcrum support to pivot said permuting arm and thereby selectively position said one end of said permuting arm into and out of engagement with said second terminal, said projections on said permuting arm being slightly smaller in length than the length of said recesses thereby permitting said permuting arm to have slight lengthwise sliding movement as limited by said recesses in said sidewalls, the sliding movement occuring on the edges of said fulcrum and so that the underside of said permuting arm is subject to abrasion thereby to maintain a low ohmic contact at the fulcrum end at all times.

2. The invention as defined in claim 1 wherein said rocker arm assembly include a rocker arm button, and means for Y mounting said rocker arm button for rocking movement about an axis disposed transversely to said sidewalls and lying substantially in the same plane as said projecting end of said first terminal.

3. The invention as defined in claim 2 wherein said means mounting said rocker arm button for rocking movement on said housing includes trunnions formed integral with said rocker arm button, and openings formed in said housing sidewalls in which said trunnions are journaled.

4. The invention as defined in claim 3 wherein said rocker arm button includes a rod supported for movement along an axis normal to the axis of rocking movement of said rocker arm button, said rod having a spherical end engageable with said permutingarm, and spring means engaging said rod for biasing said spherical end into engagement with said permuting arm.

5. The invention as defined in claim 4 wherein said rod is made from a plastic.

6. The invention as defined in claim 4 wherein said housing includes means engageable with the opposite ends of said rocker arm for limiting rocking movement thereof.

7. The invention as defined in claim I wherein said base includes first and second openings accommodating said first and second terminals and wherein each of said terminals includes a bent lug portion disposed normal to the plane of said terminals and engageable with the inner side of said base when said terminals are inserted through said openings from the interior of said housing and an offset prong having a free end spaced from said lug and engageable with the underside of said base to clamp said terminals on said base.

8. The invention as defined in claim 1 wherein said housing includes end walls having grooves formed on the exterior thereof adapted to accommodate spring means for attaching said switch to a panel.

Claims (8)

1. An electrical switch comprising an open-ended housing including a base disposed opposite said open end and opposing sidewalls, each of said sidewalls having a recess disposed therein in horizontal alignment with respect to one another, a first terminal mounted on said base intermediate the ends thereof and having an end projecting into said housing transversely of said sides, a second terminal mounted on said base and spaced lengthwise from said first terminal, a permuting arm supported intermediate the ends thereof solely on said projecting end of said first terminal for pivotal movement thereon between a position in which one end of said arm contacts said second terminal and a position spaced therefrom out of contact therewith, projections extending laterally from said permuting arm positioned for seatment within said recesses on said sidewalls, a rocker arm assembly mounted on said housing projecting through said open end and including means engageable with said permuting arm on opposite sides of said fulcrum support to pivot said permuting arm and thereby selectively position said one end of said permuting arm into and out of engagement with said second terminal, said projections on said permuting arm being slightly smaller in length than the length of said recesses thereby permitting said permuting arm to have slight lengthwise sliding movement as limited by said recesses in said sidewalls, the sliding movement occuring on the edges of said fulcrum and so that the underside of said permuting arm is subject to abrasion thereby to maintain a low ohmic contact at the fulcrum end at all times.

2. The invention as defined in claim 1 wherein said rocker arm assembly include a rocker arm button, and means for mounting said rocker arm button for rocking movement about an axis disposed transversely to said sidewalls and lying substantially in the same plane as said projecting end of said first terminal.

3. The invention as defined in claim 2 wherein said means mounting said rocker arm button for rocking movement on said housing includes trunnions formed integral with said rocker arm button, and openings formed in said housing sidewalls in which said trunnions are journaled.

4. The invention as defined in claim 3 wherein said rocker arm button includes a rod supported for movement along an axis normal to the axis of rocking movement of said rocker arm button, said rod having a spherical end engageable with said permuting arm, and spring means engaging said rod for biasing said spherical end into engagement with said permuting arm.

5. The invention as defined in claim 4 wherein said rod is made from a plastic.

6. The invention as defined in claim 4 wherein said housing includes means engageable with the opposite ends of said rocker arm for limiting rocking movement thereof.

7. The invention as defined in claim 1 wherein said base includes first and second openings accommodating said first and second terminals and wherein each of said terminals includes a bent lug portion disposed normal to the plane of said terminals and engageable with the inner side of said base when said terminals are inserted through said openings from the interior of said housing and an offset prong having a free end spaced from said lug and engageable with the underside of said base to clamp said terminals on said base.

8. The invention as defined in claim 1 wherein said housing includes end walls having grooves formed on the exterior thereof adapted to accommodate spring means for attaching said switch to a panel.

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