Patent Publication Number: US-4926148-A

Title: Auxiliary switch retainer for circuit breakers and actuator member

Description:
The present invention relates to a conventional circuit breaker to which is added an auxiliary switch holder wherein an auxiliary switch may be inserted or replaced in the field. The invention also relates to retainer means for releasably holding the auxiliary switch in the holder and various actuator elements positioned within the casing between the breaker mechanism and the auxiliary switch actuating means. 
     In the prior art, auxiliary switches have sometimes been used in connection with circuit breakers to be simultaneously actuated on or off as the breaker contacts are closed and released to the other condition as the breaker contacts are opened. Auxiliary switches have not been convenient to employ in the prior art. The present invention provides means integral with the breaker and permitting actuation through the breaker mechanism whereby such an auxiliary switch can be easily added in the field and conveniently removed or replaced at will. 
     In accordance with the present invention, a switch receptacle is molded as part of the circuit breaker casing. Preferably the receptacle is molded to receive snugly a specific form of commercially available auxiliary switch element at the end of the breaker opposite its switch handle so as to be accessible behind the panel in which the circuit breaker is mounted and where electrical connections are made. The receptacle is preferably a molded extension of the casing, in most cases of two mating half shells, which half shells are a conventional means of constructing the breaker casing. The switch is preferably provided with at least one hole, and usually a pair of holes aligned with holes in the receptacle which allow a switch retainer to be put through the aligned holes to hold the switch in place, and advantageously the retainer will be U-shaped as will be described. A switch actuating means, usually a pushbutton, is normally spring loaded outwardly from an edge of the switch closest to the breaker mechanism and a suitable actuator member can be employed between a moving portion of the breaker mechanism and the actuating means. The actuator member preferably is normally urged away from the actuating position by the switch spring. It is urged into actuating position by contact with the breaker mechanism as the breaker contacts are closed against the action of the switch spring. 
     More specifically, the present invention concerns a housing for a circuit breaker structure containing a circuit breaker mechanism mechanically actuated by a handle at one edge of the housing and having electrical terminals for electrical connections at the opposite edge thereof. The housing is of generally rectangular from having broad enclosing faces and at least four narrow edge walls. Access to the breaker mechanism is provided through an opening in an edge wall opposed to that accommodating the actuator handle adjacent terminals for connecting the breaker to an electrical circuit. An auxiliary switch receptacle is connected to the housing along the edge wall providing access to the mechanism. The edge wall with the opening allows communication therethrough between the breaker mechanism and the actuating means of the switch. Means extending through aligned holes in the auxiliary switch and the receptacle is provided for retaining the switch in the receptacle. An actuator member extends through the opening between the switch actuating means and a portion of the breaker mechanism and moves in response to breaker contact opening and closing. The actuator member is retained in place laterally by a portion of the housing designed for that purpose. 
     The invention also concerns a preferred construction retainer means for holding the switch in the receptacle and various types of actuator members, as will appear hereafter. 
    
    
     For a better understanding of the present invention, reference is made to the accompanying drawings, in which: 
     FIG. 1 is a somewhat schematic showing of the general layout of relevant parts of a circuit breaker with one side shell removed and employing an auxiliary switch receptacle in accordance with the present invention with an auxiliary switch in place and an actuator member in place to actuate the switch; 
     FIG. 2 is a perspective view showing the switch receptacle end of shells comprising the breaker housing in an exploded perspective view also showing the auxiliary switch and retainer; 
     FIG. 3 is a partial plan view of the opposite shell of the switch housing from that shown in FIG. 1; 
     FIG. 4a is a plan view of the actuator member in its position between the breaker mechanism and the switch actuating means when the breaker contacts are opened; 
     FIG. 4b is a similar view showing the position of the actuator member between the same elements after the switch breaker contacts have been closed; 
     FIG. 5 is a side view of the switch retainer; 
     FIG. 6 is a view showing two stages of insertion of the switch retainer of FIG. 5 through holes in the sidewalls of the receptacle and holes in the auxiliary switch; 
     FIG. 7 is a partial view similar to FIG. 1 showing a different kind of breaker mechanism and a different actuator member in open breaker contact position; 
     FIG. 8 is a similar view showing the actuator member of FIG. 7 with the breaker in closed contact position; 
     FIG. 9 is a perspective view of a preferred slide actuator member for use in the embodiment of FIGS. 7 and 8; 
     FIG. 10a is a plan view from above of the actuator member of FIG. 9; and 
     FIG. 10b is a side elevation view of the actuator member of FIG. 9. 
    
    
     Referring to FIG. 1, there is shown a partial view of some of the interior linkage structure of a circuit breaker, generally designated 10 with one half shell of the casing removed and only the right half shell 12 shown in outline. The type of circuit breaker and housing employed are similar to those shown in U.S. Pat. Nos. 3,955,162 and 4,267,539, for example. The breaker mechanism, generally designated 14, includes a frame 16 mounted on the housing and various linkages rotatably supported thereon. An actuatable member 18 is moved by actuator 20 attached to manual breaker switch handle 22 extending through an opening into the breaker casing 12, wherein it is rotatably supported relative to the housing. At the other end of the housing is the movable contact support 24 carrying the movable breaker contact 26 pivotally supported to rotate about pin 28 on the frame 16. Movable contact support 24 is joined to the actuator linkage mechanism by a pin 30 which allows the contact support 24 to be moved down so that the movable breaker contact 26 closes against the fixed breaker contact 32. Fixed contact 32 is supported on the housing shell 12 and connected to external terminal 34. Movable contact 26 through a conductive circuit (not shown) is connected to external terminal 36. These external terminals are the means by which the breaker is connected into the protected circuit. Ordinarily a breaker will be secured to a panel so that its manual breaker switch handle 22 is accessible but the rest of the breaker, including its electrical connections, is safely behind the panel. 
     In accordance with the present invention, the molded casing supports the switch receptacle 38. In a preferred embodiment as shown, the right shell 12 is molded integrally with one half of auxiliary receptacle 38 of the same resinous material. Similarly the other half of the receptacle 38&#39; is molded integrally with the left shell 12&#39;. As seen in FIG. 2, the two mate to form the completed receptacle when the breaker housing shells are assembled. As seen in FIG. 2, the extension 38 is provided with a recess 40, 40&#39; preferably conforming to the shape and size of an auxiliary switch 42. 
     In passing, it should be noted that the switch receptacle need not be molded but may be attached to either or both shells in some other manner and the receptacle need not be conforming provided it is capable of holding the switch stationary with respect to the breaker. The switches themselves may vary and the receptacle is designed for a specific switch which may have any number of terminals, but is shown here as having three, protruding away from the receptacle in position for convenient circuit connection. 
     This particular switch is provided with a spring-loaded switch actuating means in the form of a plunger 44. The spring urges the plunger into the extended position shown in FIGS. 1 and 4a, representing one condition of the auxiliary switch. When depressed inwardly against the loading of its internal spring, the plunger produces the other condition of the switch 42. Between the plunger 44 and the breaker contact arm 24, and more specifically a protrusion 24a thereof, is an auxiliary switch actuator member 46. The auxiliary switch actuator member is designed to be moved into the switch actuating means, plunger 44, to change switch condition. In this embodiment the spring of the plunger will return the plunger and actuator member to its rest position of FIG. 4a when the movement of the breaker mechanism permits. 
     As seen in FIG. 2, in the left shell, and specifically in the switch receptacle extension 38&#39; thereof, there is a recess 48&#39; which is designed to receive auxiliary switch retainer 50, or more specifically the top 52 thereof. Top 52 may be made to conform to the casing 38 when fully inserted. Auxiliary switch retainer 50 has two resilient prong members 54a and 54b, respectively, preferably provided with cam members 56a and 56b and terminated in shoulder latch means 58a and 58b as lateral extensions at the ends of prongs 54a and 54b. Parallel holes 60a and 60b receive the prongs 54a and 54b, respectively. When the auxiliary switch is in position in the receptacle, a pair of aligned holes 62a and 62b permit passage of the prongs which then pass in turn through to holes 64a and 64b in the extension 38 of right shell 12. The cams 56a and 56b engage the sidewalls of the holes 62a and 62b and urge the bottom portion of the prongs toward one another so that as they pass out the bottom of holes 64a and 64b, the latch shoulders 54a and 54b will engage the outside of the right shell. In most cases rather than the actual shell surface, each hole 64a and 64b is enlarged to provide a latch opposing shoulder or ledge below the shell surface to permit engagement should the latch means 58a and 58b move into position. FIG. 5 shows another more detailed view of the auxiliary switch retainer. FIG. 6 is a somewhat diagrammatic view showing the retainer pronts 54a and 54b about to complete passage through the holes (in phantom) and in latched position (solid lines). It will be observed that the holes have to be larger than the prong in order to accommodate passage of the latch means 58a and 58b and in order to allow the cams 56a nd 56b to function even though the prong member 54a and 54b are resilient. The cams may be omitted in some embodiment but are desirable to positively urge the latching. In FIG. 6 the recessed shoulder 66a and 66b, which cooperate with the latch portions 58a and 58b of the prong, can be seen. It will be understood that the retainer 50 need not have a conforming part 52. However, while simple pins or screws would hold the switch in position, the retainer provides a simple, easily inserted and easily removed device which may be left in place even when not in use to hold the switch. The latch means are preferably not straight shoulders but curved so as to allow camming away from the retaining shoulders as force is applied to member 52 to withdraw the retainer. The resilience of the retainer 50 will allow necessary flexing and materials for the prongs at least should be selected with the need for flexing in mind. 
     The auxiliary switch actuator member 46 is seen in greater detail in FIGS. 4a and 4b, which illustrate a preferred shape of the compressible embodiment. The actuator member 46 seen in these Figs. is preferably made of a highly resilient, rubber-like material such as Santoprene 251-92 which may be described as thermoplastic rubber. The actuator may take various forms but the form shown is preferred. In this form it consists of a sole 68, a deformable bumper 70, an interconnecting web 72 and a reinforcing longitudinal rib 74 at right angles to web 72 and effectively extending through it. Extending from both sides of the reinforcing web 74 and along the top of the base 68 are guide pin members 76, 76&#39;, 78, 78&#39;. The bumper 70 may assume various shapes. Its sole support to the rest of the structure is the connecting web 72 and the gaps between the bumper 70 and the rib 74 may be calculated to accomplish various functions. On the end of the bumper which is primarily in contact with the actuator portion 24a of the contact arm 24, the structure is intended to flex, and adequate space is allowed for it to flex very substantially, effectively compressing the actuator before contacting the rib 74. On the opposite end, however, the gap between the bumper and rib 74 may be small since the movement is designed to be away from the spacing and by keeping the space small when pressure is released, the deformable actuator may rebound into a part of the rib 74 which will tend to damp its movement. The pins 76 and 78 ride in grooves 80 and 82 in the opening of right shell 12 toward the recess 40. As seen in FIG. 3, similar grooves 80&#39;, 82&#39; in the left shell 12&#39; engage pins 76&#39;, 78&#39;. The pins are engaged in the respective grooves which guide them to the left as viewed in FIGS. 1 and 2. Thus as seen in FIG. 4b, as pressure is applied by actuator member 24a to bumper 70, the actuator as a whole is pushed toward the switch 42. The pins 76, 76&#39; and 78, 78&#39; guided by the slot 80, 80&#39; and 82, 82&#39; simultaneously guide the actuator as a whole to the left. Being composed of a resilient material, the bumper also deflects when the whole actuator deflects and compresses to some extent. Thus instead of moving directly into the plunger, part of the movement is diverted laterally and part of it is absorbed as compression in the actuator member which allows the switch to be adequately depressed through plunger 44 without being damaged. It will be clear to those skilled in the art that other forms of actuator could be provided, provided it is suitably confined by the housing structure or otherwise guided and retained from one position to another. 
     The embodiment of FIGS. 7 through lOb applies to another type of breaker shown in U.S. Pat. No. 4,618,745, for example. In this embodiment, corresponding parts are given corresponding numbers of those of the embodiment of FIGS. 1-6 with prefix 1 in the hundreds digit. In FIG. 7 the breaker contacts 126 and 132 are open. In FIGS. 7 and 8 the actuator 90 is no longer the compressible device 46 of FIGS. 1 to 6. Instead it is a rigid slide member 90 depicted in FIGS. 9, 10a and 10b, extending from within the switch receptacle through a hole in the housing to bear against an outside wall of housing 112. Providing a broad flat surface slide portion 92 may serve both as switch actuator guided slide and as a breaker condition indicator even when an auxiliary switch is not used. Slide member 92 passes through a confining slot 143 in the sidewall of receptacle 138 and slides along edge 112, 112&#39;. When extended as in FIG. 7, the slide 92 covers a contrasting colored patch 145, which may be red, for example, and indicate that the breaker contacts are open. When in the position of FIG. 7, the red patch 145 is not seen but when the slide is in the position of FIG. 8, with the breaker contacts closed, the red patch 145 is clearly visible. A service man from the rear of the breaker would know from the visible red patch that the switch contacts were closed. The outer surface of the end of the slide may be a different color, such as green, to indicate breaker contacts open. Within switch receptacle 138 is a transition member 94 connected to slide 92. Member 94 which provides a stop 95 against a wall 141 of the receptacle 138, limiting movement of the slide 90. Extending through a narrow confining slot between the housing shells and the switch retainer cavity is a narrow L-shaped connector 96. The slot is made confining to help guide the structure laterally. Once within the casing, this narrow transition member flattens parallel to the inside of casing wall 112 and broadens into a slide structure 98 following the edge wall. Attached to either edge of the side structure 98 are a pair of similar hook members 100a and 100b whose curved ends 102a and 102b are designed to engage wings 128 above the movable contact 126 as the contact arm 124 moves the contact into the closed contact position of FIG. 8 and then pull the slide 90 along with it (to the right in FIGS. 7 and 8). This action moves the slide 92 away from patch 145 indicating the contacts are closed. 
     When the contacts open, the switch contact itself pushes the slide as seen in FIG. 7 contacting the bridging member 99 between the arms 100a and 100b before it moves up to the higher dashed line position. The contacts are now open and the red patch 145 is covered. 
     While the above-described embodiments constitute currently preferred embodiments of the invention, variation on structure, shape and configuration will occur to those skilled in the art. All such modifications and variations within the scope of the claims are intended to be within the scope and spirit of the present invention.