Abstract:
An appliance switch has a one-piece housing defining separate cavities for the rocker/actuator and for the switch contact elements. An inner wall of the housing is integrally formed for this purpose, and defines a boss for slidably receiving a plunger that engages the rocker/actuator. The contact elements are identically shaped, each having an L-shape configuration with a resilient leg engageable with the plunger, and with a plunger hole that receives the plunger in the fixed contact element. A cover closes the cavity for the fixed and movable contact elements and also serves to hold them in place.

Description:
This invention relates generally to door operated appliance switches and deals more particularly with a switch adapted to be held closed by the door of a refrigerator or freezer. 
     In the environment for appliance switches of the type used in refrigerators or freezers at least a portion of the switch is necessarily exposed to above average wear and tear in that cleaning solutions or the like are apt to be used to clean the refrigerator or freezer, and such solutions can effect the electrical conductors provided within the switch housing. The present invention seeks to provide a sealed environment for the switch contacts themselves, and to provide for draining off such solutions from that part of the switch into which such solutions are apt to enter. 
     PRIOR ART 
     In U.S. Pat. No. 4,514,603 there is described and claimed a switch in which two compartments are provided for, one being for the switch elememnts and one for the switch actuating elements. The switch housing in this prior art design entails use of a three part housing which must be assembled in order to provide a switch with two isolated compartments or cavities. More particularly, the divider wall between the two compartments is formed in a member which is inserted into the bottom of the housing itself, requiring a third part in the form of a base or cover to close the compartment for the switch elements. 
     The present invention seeks to obviate the need for such a three part housing, and to provide further advantages in the configuration for the fixed and movable contact elements. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention a generally rectangular one-piece switch housing is provided having an upwardly and a downwardly open cavity separated by and internal wall defined integrally with the housing itself. A plunger is slidably received in a boss provided in the internal wall of the housing, and the upper end of the plunger provided in the upwardly open cavity engages the underside of a pivotably mounted rocker in the upper cavity. Fixed and movable switch contact elements of identical configuration are provided in the downwardly open cavity and one of these contact elements is fixed in position by an abutment on the integral housing wall while the other contact element is movable, being engaged by the lower end of the plunger which extends through an opening in the fixed contact element. 
     Each of the two identical switch elements is of a generally L-shape having a cantilevered resilient portion and a terminal blade portion that projects outside of the switch housing. These fixed and movable contact elements are provided one above the other in the switch housing, and a lower cover is provided for closing the cavity in which these switch elements are housed. 
     The rocker is provided pivotably adjacent one end of the upper cavity in the housing so that the free end of rocker is adapted to move through a larger displacement than that of the plunger itself. Two slots are provided in the opposite end of the upper housing cavity. The lower ends of these slots are at the same height as the integral inner wall defined by the housing so as to drain off any excess liquid from the upper cavity. These slots serve to receive tabs provided for this purpose on the rocker itself and have upper ends that define the upper limit position for the rocker. These tabs may engage the inner wall to determine the lower limit position for the rocker. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a vertical sectional view through an appliance switch constructed in accordance with the present invention. 
     FIG. 2 is a sectional view taken generally on the line 2--2 of FIG. 1. 
     FIG. 3 is a perspective view taken from above and to the right illustrating the fixed contact to FIG. 1. 
     FIG. 4 is a perspective view from above and to the right illustrating the movable contact of FIG. 1 (both the fixed and movable contact elments of FIGS. 3 and 4 being identical). 
    
    
     DETAILED DESCRIPTION 
     Turning now to the drawings in greater detail, a switch embodying the present invention is illustrated in vertical section in FIG. 1 with the movable parts in alternative positions, the solid line position indicating the switch in its &#34;on&#34; condition and the phantom line position indicating the switch components in their &#34;off&#34; condition. 
     The switch comprises a generally rectangular housing 10 having upwardly and downwardly open cavities 10k, 10m separated by an internal wall 12 that is defined integrally with the housing 10. 
     The housing 10 includes oppositely arranged end walls one of which is illustrated at 10a and the other being illustrated at 10b in FIG. 1. The side walls 10c and 10d are illustrated in FIG. 2, and these walls 10a, 10b, 10c and 10d cooperate with one another to define a generally rectangular external configurations for the housing. A flange or bezel portion 10e is provided at the upper end of the housing 10 so that the switch can be conveniently mounted in a rectangular opening provided for it in the path of movement of the door of the appliance to be equipped with a switch in accordance with the present invention. Although not shown in the drawings, panel mounting wings may be provided on at least one side or end of the switch housing to facilitate installation of the switch in an appliance door opening. 
     A vertically reciprocable plunger 14 is provided in a boss 12a and more particularly in an opening defined by the boss 12a provided for this purpose in the integrally formed wall 12 of the housing 10. As so arranged the plunger 14 can be moved between the positions shown in solid and phantom lines in FIG. 1. The plunger 14 is formed of an insulating plastic material similar to that used in the housing 10, and may include a flanged portion 14a adapted to engage the underside of the wall 12 of the housing 10 to define the upper limit position for the plunger. 
     A rocker 16 is pivotably provided in the upper cavity 10k defined by the housing 10 and this rocker 16 is movable from a solid line position as shown in FIG. 1 to the phantom line position of FIG. 1 either manually or by reason of shutting the door of an appliance equipped with the switch constructed in accordance with the present invention. The rocker 16 has axle defining portions 16a provided in aligned openings in the side walls 10c, 10d of the switch housing 10. Thus, means is provided for pivotably mounting the rocker 16 and said means is defined in part by the rocker itself and in part by the housing 10 so as to define a pivot axis for the rocker located adjacent the one wall 10a of the housing 10 and more particularly between this wall and the boss 12a which slidably supports the plunger 14. 
     Still with reference to the rocker 16 this component is also fabricated from an insulating plastic material and is substantially hollow defining a downwardly facing surface 16d that abuts the upper end 14b of the plunger 14, and the rocker 16 further defines at least one and preferably two projecting tabs 16b that move in slots 10f defined for them in the housing end wall 10b opposite the one wall 10a referred to previously with reference to the pivot axis of the rocker 16. These tabs 16b are adapted to engage the uppermost end of the slots 10f in order to define an upper limit position for the rocker 16 as best shown in FIG. 1. The down or lower limit position for the rocker 16 illustrated in phantom lines in FIG. 1 is determined by engagement between these same tabs 16b and the top of the integral inner wall 12 of the housing 10 as illustrated generally at 12b in FIG. 1. Alternatively, or to provide a supplementary limit stop for the down position of the rocker 16 a second projecting tab 16c may be provided on the rocker for engaging a detent provided for this purpose in the housing bezel 10e as indicated generally at 10g in FIG. 1. 
     Turning next to the downwardly open cavity 10m which houses the fixed and movable switch contact elements, the contact elements are prefrably fabricated from conductive material such as sheet metal and each contact element may include a precious metal contact abutment surface 18 or 20. The contact abutment surface 18 is best shown in FIG. 4. 
     The fixed contact element 22, that is the upper contact element associated with abutment surface 18, has an opening 22a for loosely receiving the lower end 14c of the plunger 14 and to provide clearance for the plunger so that the tip of the plunger can engage the movable contact 24. Actually, the contact elements 22, 24 are identical to one another and the fixed contact element 22 is held from movement by a depending web or flange 12c provided for this purpose on the integral inner wall 12 of the housing 10. The movable or lower contact element 24 is not so supported and is therefore movable by the plunger from the solid line position shown for it in FIG. 1 to the phantom line position illustrated in that view. Each contact element 22 and 24 is held in place by reason of its blade type terminal leg portions being received in slots defined for them in the housing and more particularly adjacent the walls defining the downwardly open cavity 10m of the housing. FIG. 1 illustrates the slots at 10h and 10j for each of these contact elements 24 and 22 respectively. FIG. 2 illustrates one of these slots 10h and its relationship to the leg portion of the L-shaped contact element 24 received therein. FIGS. 3 and 4 illustrate the upper or fixed contact element 22 but it will be noted that the element 24 referred to previously is identical thereto and these contract components need only to be mounted so that their abutment surfaces 18, 20 contact one another as suggested in FIGS. 1 and 2 in the process of assembling a switch in accordance with the present invention. More particularly, and as best shown in FIGS. 3 and 4 each contact element 22 or 24 comprises a generally L-shaped configuration such that an initially flat sheet of metal can be bent into the configuration shown in order to form a relatively thick blade or terminal leg portion 22b and to provide a relatively resilient cantilevered leg portion 22c upon which is mounted the precious metal abutment contact 18. The location for the opening 22a is such that when this contact element of FIGS. 3 and 4 is provided in position to define a so-called fixed contact element for the switch the plunger 14 will pass through the opening 22a as described previously. On the other hand, when the contact element 22 is to be provided in the configuration illustrated for it in the lower or movable contact element position of FIGS. 1 and 2 the opening 22a will not be required for functional operation of this switch, but applicant has achieved a switch construction such that the same contact element 22 or 24 can be used for either the fixed or the movable contact in a switch embodying the features of the present invention. 
     Finally, the downwardly open cavity 10m for these switch contact elements is closed by a cover or base 26 having upstanding lugs 26a that are received in openings provided for them in the lower edges of the end walls 10a and 10b of the housing 10. One of these posts and preferably two of them 26b and 26c are so oriented and located that they engage the underside of the movable contact element 24 as best shown in FIG. 2 in order that this contact element be supported properly in its slot 10h and not tend to move downwardly in the slot in response to downward movement of the plunger 14 during use or operation of the switch. Post 26b as shown in FIG. 2 is itself adequate to prevent such inadvertent motion of the blade terminal portion of the movable contact element 24.