Patent Publication Number: US-4321443-A

Title: Lighted toggle lever switch having articulated conductors

Description:
BACKGROUND OF THE INVENTION 
     Lighted toggle lever switches have been known heretofore. For example, J. J. Keranen U.S. Pat. No. 3,614,362, dated Oct. 19, 1971, shows such a switch having a lamp bulb within the hollow toggle lever, molded plastic ball-and-socket structure for pivoting the toggle lever in the bushing, and a pair of lateral helical compression springs extending from recesses in the toggle lever ball on its pivotal axis and contacting terminals extending up within opposite sides of the bushing. Also, E. T. Piber U.S. Pat. No. 4,055,739, dated Oct. 25, 1977, shows such a switch having a light emitting diode within the hollow toggle lever, molded plastic ball-and-socket structure for pivoting the toggle lever in the bushing, and right-angle bends on the two LED terminals so as to be biased outwardly into contact with the upper ends of a respective pair of inwardly-biased terminals mounted in the bushing. In both of these patents, current is conducted from stationary terminals in the switch housing, or bushing, to the movable light indicator within the pivotal toggle lever. 
     While these prior switch structures have been useful for their intended purposes, this invention relates to improvements thereover. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide a metal bushing type electric switch with improved means for conducting electric current from stationary terminals in its housing to a movable light indicator within its pivoted operating lever. 
     A more specific object of the invention is to provide a lighted toggle lever switch with improved pivotal lever structure accommodating articulated electrical connector means. 
     Another specific object of the invention is to provide a lighted pivotal actuator switch with improved means conducting current from stationary terminals to an indicator in the movable actuator without impeding actuation of the latter. 
     Another specific object of the invention is to provide a toggle switch with bushing structure that is especially adapted for accommodating articulated connectors for an indicator light within the lever handle. 
     Another specific object of the invention is to provide a lighted toggle lever switch with improved lever pivoting bushing structure that is economical to manufacture and easy to assemble. 
     Other objects and advantages of the invention will hereinafter appear. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partly lateral cross-sectional and partly elevational view of a lighted toggle lever switch showing the bushing insulator structure and articulated conductors; 
     FIG. 2 is a horizontal cross-sectional view taken through the bushing substantially along line 2--2 of FIG. 1 to show the upper end configurations of the lamp terminals; 
     FIG. 3 is a top view of one of the two like bushing insulator halves used in the switch of FIGS. 1 and 2 and showing the integral trunnion and the mounting holes thereon; 
     FIG. 4 is an elevational view of the bushing insulator half of FIG. 3 showing its joining surface configuration, the integral trunnion, bushing bore and channel for accommodating one of the lamp terminals; and 
     FIG. 5 is a bottom view of the bushing insulator half of FIGS. 3 and 4 showing the horizontal portion of the channel for accommodating one of the lamp terminals. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1 and 2, there is shown a lighted toggle lever switch having articulated conductors and constructed in accordance with the invention. As shown therein, this switch is provided with a housing comprising a molded insulating base 2 and a metal cover 4 having a relatively large hole at its center to which an externally-threaded bushing 6 is attached, such bushing being made of metal such as brass or the like. 
     While base 2 is shown only schematically, this base and the switch contacts therein are known in the art and reference may be had to A. W. Krieger U.S. Pat. No. 1,998,962, dated Apr. 23, 1935, for an illustration and description thereof. A base of this type may house single-throw bridging contacts that close when the toggle lever is actuated in one direction and re-open when the toggle lever is swung back in the other direction as shown in the above Krieger patent but other types are possible. A base of this type also has a pair of vertical holes through which rivets or bolts extend to mount the cover thereto as hereinafter more fully described. 
     Cover 4 is a generally rectangular metal plate having a round hole at its center with the edge of the plate around this hole being slightly formed upwardly to provide enough space for the lower end of bushing 6 to be flared thereunder when the bushing is secured to the plate and with the flared end of this bushing being substantially flush with the lower surface plane of the plate. Thus, the rim of the hole in this cover will be pinched between the lower flared end and the thicker-wall, threaded portion of this bushing rigidly to secure the bushing to the cover plate. 
     Bushing 6 is externally threaded so that it can be pushed through a round hole in a mounting panel and a nut turned thereon to mount the switch to the panel. Such hole in the panel would have a key in one side thereof that enters a keyway 6a shown in FIG. 1 to keep the switch from turning when in use. 
     The switch is actuated by a pivotal operating member such as a toggle lever 8. As shown in FIG. 1, this toggle lever is pivotally supported within the bushing at substantially its mid-portion, has an external handle portion at one end that is grasped by the user to actuate the switch, and has an innr contact-operating portion at its other end that moves the contacts between open and closed positions as the handle portion is manipulatedin the usual manner for a switch of the toggle lever type. 
     This toggle lever comprises a main lever 10 and a lens or cap 12 secured to its external end. This main lever is provided with pivot means comprising an enlarged, generally spherical or convex mid-portion 10a that is in close association with a contiguous concave bore within the bushing as shown in FIG. 2 to close the bushing as well as possible against entry of dirt or the like. This main lever pivot means also comprises a lateral hole 10b through this enlarged portion of the lever for accommodating pivoting trunnions 14a and 16a of a pair of bushing liner or insulator halves 14 and 16 as shown in FIG. 1. As shown therein, these trunnions extend into opposite ends of this lateral hole 10b in the main lever to pivot the lever for limited pivotal movement in the bushing. 
     This main lever is also provided with means for supporting an indicator lamp 18 in its external handle portion. This means comprises a hollow section extending from lateral hole 10b all the way through the external portion of main lever 10. This hollow section comprises a hole 10c of uniform cross-section extending up from lateral hole 10b for retaining concentric connectors 20 and 22 which hole then flares out to a larger diameter 10d for retaining the base of lamp 18 as well as the upper end 20a of inner connector 20 and the enlarged diameter upper end 22a of outer concentric connector 22. The extreme upper end portion of such larger diameter hole is provided with internal threads 10e for retaining the externally-threaded lower end 12a of lens 12 that covers the lamp bulb. While main lever 10 is a plastic molded member made of nylon or the like, cap 12 is a plastic molded member of polystyrene or the like that may be transparent or translucent to transmit the light from the lamp bulb as an indication of switch operation or the like. On the other hand, this lens cap 12 may be colored such as red or green, for example, while still conducting sufficient light to give an indication. 
     Inner connector 20 is a helical spring of uniform diameter that contacts at its upper end the center contact of the base of lamp bulb 18 and contacts at its lower end the internal end of terminal 24. This inner helical spring is compressed between terminal 24 and the lamp bulb sufficiently to provide the necessary contact pressure for a good electrical connection. This inner helical spring is surrounded by an insulator tube 26 having a notch 26a at its lower end to provide access for the narrow tip of terminal 24 while providing insulation the rest of the way around to prevent contact with either terminal 28 or helical spring 22. 
     As shown in FIG. 1, outer helical spring connector 22 surrounds insulator tube 26 within the hole or bore 10c. The upper enlarged-diameter end of this spring 22 contacts the concentric outer contact of the lamp bulb while the lower end of this spring contacts terminal 28. This spring 22 also is in sufficient compression to provide the necessary contact pressure for a good electrical connection. Terminals 24 and 28 may be made of brass or the like for good electrical conductivity. 
     As shown in FIG. 2, terminal 24 has a narrow tip 24a that is bent up so that it extends up into the lower end of inner helical spring connector 20 as shown in FIG. 1 and makes contact therewith. As shown in FIG. 2, terminal 28 has a partial-circular tip 28a so as to surround tip 24a about two-thirds of the way around and in spaced relation thereto, thus providing a contacting seat for outer helical spring connector 22. This partial-circular terminal tip 28a has an inner diameter large enough to allow the lower end of insulator tube 26 to extend freely therethrough so that notch 26a rests on terminal 24. Connector springs 20 and 22 are made of metal such as phosphor bronze or the like so as to provide good electrical conduction and maintain contact bias between the two terminals and the lamp bulb. Insulator tube 26 may be made of electrical grade fibre or the like to afford effective electrical insulation between the parts. 
     This switch is also provided with means for performing a number of desirable functions or results, among which are: providing mounting means for lamp terminals 24 and 28 while concurrently insulating these terminals from the metal cover and bushing, supporting these terminals in such a way as to adapt the toggle lever for retaining articulated connectors between these terminals and the indicator lamp, and providing pivoting means for the toggle lever such that the articulated connectors will not impede pivotal actuation of the toggle lever while concurrently keeping the bushing closed to prevent entry of dirt into the switch housing. These are accomplished by two like molded parts hereinafter described. 
     This lamp terminal retaining and toggle lever pivoting means comprises a pair of like bushing insulator halves 14 and 16, one of which, 14, is shown in FIGS. 3-5. This insulator half is a plastic molded member of nylon or the like and comprises a generally flat cover plate portion 14b having two half-circle tabs 14c and 14d near the opposite ends of the longitudinal joining edge thereof with a half-bushing liner 14e extending up therebetween. As shown in FIG. 4, tabs 14c and 14d are in the planes of the lower one-half and the upper one-half of the thickness of plate portion 14b, respectively, so as to provide inter-fitting engagement when insulator halves 14 and 16 are put together and inserted into the metal bushing of the switch. These tabs 14c and 14d are also perforated in line with the joining edge of plate portion 14b to provide rivet holes 14f and 14g superimposed under and over the respective holes of insulator half 16 when the two insulator halves are brought together. The remainder of the abutting surfaces of the insulator halves are flat or complementary to one another to make a tight joint when the parts are assembled. As aforementioned, insulator half 14 is provided with a short trunnion 14a that enters one end of the lateral hole in the enlarged spherical portion of the toggle lever for pivotally supporting the latter. As shown in FIG. 4, insulator half 14 is also provided with a vertical channel 14h within its bushing liner 14e which joins at its lower end a horizontal channel 14j extending to the outer edge of plate portion 14b for accommodating terminal 24. As shown in FIGS. 4 and 5, vertical channel 14h has narrow vertical lips 14k at opposite sides behind which vertical portion 24 of the terminal is slid upwardly to confine the terminal therein and prevent it from tipping toward the other terminal when spring 20 is placed in compression by assembly of the lamp bulb and cap. To fit this channel, the external portion of terminal 24 as well as the adjoining horizontal portion 24b and the next adjoining vertical portion 24c are of equal width to fit channels 14h and 14j. Also, chanel 14h extends up to the center of trunnion 14a for non-impeding toggle lever actuation purposes. The next adjoining horizontal portion 24d of the terminal is narrower so that it can emerge between lips 14k as shown in FIG. 2 and extend into the center of the lateral hole in the toggle lever. The horizontal portion 24d then narrows again into tip 24a before it turns up into the center of connector spring 20 as shown in FIG. 2. Insulator half 14 is further provided with two tabs 14m and 14n shown in FIGS. 4 and 5 extending down from opposite sides of horizontal channel 14j that are heat-formed toward one another below horizontal portion 24b of the terminal as shown in FIG. 1. To facilitate this forming operation, grooves 14p and 14q, shown in FIG. 5, are provided in the bottom of cover plate portion 14b around the outside of tabs 14m and 14n so that these tabs can readily be formed below terminal 24 flush with or above the lower surface of cover plate portion 14b. In this manner, insulator half 14 locks terminal 24 in place so that it does not slip out of place when the remainder of the switch is assembled. 
     As partly shown in FIG. 1, the side lugs 30 of a generally U-shaped bridging contactor are pivotally supported in notches at the center-top of opposite side walls of the base. Since the lamp terminals overlie these notches, a secondary function of the formed-over tabs 14m and 14n is to insulate the lamp terminals from the bridging contactor. 
     From the foregoing, it will be apparent that the switch can be assembled by first inserting the lamp terminals up into the channels in the insulator halves and forming the tabs over to lock them in place. The trunnions of the insulator halves are next inserted into the opposite ends of the lateral hole in the main toggle lever as the insulator halves are straddled around the toggle lever. With the joining surfaces of these insulator halves held together and the lever therebetween, this subassembly is then inserted up into the metal bushing-cover subassembly such that the cover plate portions of the insulator halves abut the metal plate and the rivet holes in both are superimposed. This subassembly is then placed over the switch base having the contacts preassembled therein and the cover is riveted to the base. The outer helical spring connector is next dropped down into the hole in the lever, followed by the insulator tube and the inner helical spring connector, making sure that the notch on the insulator tube falls over the tip of the inner terminal. The lamp bulb is then placed into the cap, these two being so dimensioned that the lamp bulb is self-retaining therein by friction or the like. Finally, the lamp cap is threaded into the external end of the lever to complete the assembly. 
     In operation, when the toggle lever is actuated in either direction as indicated by the arrows in FIG. 2, connector springs 20 and 22 will flex near their lower ends while remaining seated on and in good electrical contact with tips 24a and 28a of the lamp terminals due to these connector springs being in compression between the lamp bulb and the lamp terminals. However, this compression is not so much as to close the spring turns but to leave them open. Thus, these connector springs impose negligible resistance to the free movement of the toggle lever as it pivots on the trunnions of the straddling insulator halves held in the bushing while maintaining a good electrical connection to the lamp bulb. 
     From the foregoing, it will be apparent that the invention provides a metal bushing type lighted toggle lever switch that is simple in construction and uses a minimum number of parts and is easy to assemble. For example, this construction eliminates the need for an insulating plate between the base and the cover as well as the toggle lever pivot pin used in prior switches such as that shown in the aforementioned Krieger patent. Moreover, this construction also solves the problem of mounting, insulating, and articulating the connectors between the switch housing and the lamp bulb in the tip of the toggle lever in a metal bushing switch. 
     While the apparatus hereinbefore described is effectively adapted to fulfill the objects stated, it is to be understood that the invention is not intended to be confined to the particular preferred embodiment of lighted toggle lever switch having articulated conductors disclosed, inasmuch as it is susceptible of various modifications without departing from the scope of the appended claims.