Patent Publication Number: US-6710273-B1

Title: One piece pre-molded environmental seal for toggle switch

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to the sealing of toggle switches, such as panel mounted toggle switches, in order to prevent moisture and other contaminants from passing through the switch. 
     BACKGROUND OF THE INVENTION 
     A toggle switch has a toggle lever that is typically pivoted about a pin in order to control the position of a switch. The pin passes through a bushing and the toggle lever so as to support the toggle lever. Toggle switches are used in a variety of applications and are frequently mounted to panels such that the toggle levers of the toggle switches protrude from one side of the panels and extend through the panels to operate switches on the other side of the panels. A seal is usually provided between the toggle lever and the switch in order to prevent moisture and other contaminants from passing around the toggle lever and into the switch. 
     The current method of sealing a toggle switch is to over mold the toggle switch with a material such that the material fills the area between the bushing and the lever/pin combination. This over molding process is a specialized process that is expensive to implement. The present invention is directed to a less expensive seal. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the present invention, a toggle switch comprises a switch cover, a toggle lever, a seal guard, and a one piece pre-molded seal. The switch cover has an opening. The toggle lever extends through the opening of the switch cover. The seal guard is associated with one of the switch cover and the toggle lever. The one piece pre-molded seal surrounds the toggle lever and provides sealing between the toggle lever and the switch cover, and the one piece pre-molded seal abuts the seal guard. 
     In accordance with another aspect of the present invention, a toggle switch comprises a switch cover, a switch case, a toggle lever, and a one piece pre-molded seal. The switch cover has an opening. The toggle lever extends through the opening of the switch cover. The one piece pre-molded seal has a neck portion and a planar portion, the neck portion surrounds the toggle lever and provides sealing between the toggle lever and the switch cover, and the planar portion provides sealing at an interface between the switch case and the switch cover. 
     In accordance with still another aspect of the present invention, a toggle switch comprises a switch cover having an opening, a switch case, a toggle lever, a pin, and a one piece pre-molded seal. The toggle lever extends through the opening of the switch cover and into the switch case. The pin extends through the switch cover and the toggle lever so as to form a pivot for the toggle lever. The one piece pre-molded seal has first and second portions. The first portion surrounds the toggle lever and the pin to provide sealing between the toggle lever and the switch cover and around the pin, and the second portion is between the switch cover and the switch case. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features and advantages will become more apparent from a detailed consideration of the invention when taken in conjunction with the drawings in which: 
     FIG. 1 is an isometric view of a toggle switch according to one embodiment of the present invention; 
     FIG. 2 is a view showing the separate toggle lever and switch subassemblies of the toggle switch shown in FIG. 1; 
     FIG. 3 shows the toggle lever subassembly of FIG. 2 in greater detail; 
     FIG. 4 is an exploded view of the toggle lever and seal of the toggle lever subassembly of FIG. 2; 
     FIG. 5 is a cross-sectional view of the toggle switch shown in FIG. 1; 
     FIG. 6 shows detail of the switch case and the switch cover of the toggle switch shown in FIG. 1; 
     FIG. 7 is an exploded view of a toggle lever and seal according to another embodiment of the present invention; 
     FIG. 8 shows in greater detail the toggle lever subassembly of the embodiment of FIG. 7; and, 
     FIG. 9 is a side view of the seal shown in FIGS.  7  and  8 . 
    
    
     DETAILED DESCRIPTION 
     A toggle switch  10  according to one embodiment of the present invention is shown in FIGS. 1-6. The toggle switch  10  includes a toggle lever subassembly  12  and a switch subassembly  14  that are joined together in known fashion. The switch subassembly  14  includes a switch case  16  that houses a switch (not shown). 
     A switch cover  18  of the toggle lever subassembly  12  abuts the switch case  16  when the toggle lever subassembly  12  and the switch subassembly  14  are joined together as shown in FIG.  1 . As shown in FIG. 3, the toggle lever subassembly  12  includes the switch cover  18 , a toggle lever  20 , a one piece pre-molded seal  22 , and a pin  24 . 
     The one piece pre-molded seal  22  has a planar portion  25  that is sandwiched between the underside of the switch cover  18  and an upper outwardly facing quadrilateral rim  26  of the switch case  16  when the toggle lever subassembly  12  and the switch subassembly  14  are joined together. The one piece pre-molded seal  22  also has a neck portion  27  extending away from the planar portion  25 . 
     As shown in FIGS. 4 and 5, the neck portion  27  of the one piece pre-molded seal  22  has an opening  28  that receives the toggle lever  20 . The one piece pre-molded seal  22  has an upwardly facing circular inner rim  30  that engages and is captured by a bottom surface of a corresponding downwardly facing circular ledge  32  of the toggle lever  20 . The one piece pre-molded seal  22  also has an upwardly facing circular outer rim  34  that engages and is captured by a bottom surface of a corresponding downwardly facing circular ledge  36  of the switch cover  18 . The one piece pre-molded seal  22  further has a downwardly facing circular inner rim  38  that engages and is captured by a top surface of a corresponding upwardly facing circular ledge  40  of the toggle lever  20 . Finally, the one piece pre-molded seal  22  has a downwardly extending outer cylindrical portion  42  that joins the planar portion  25  and the neck portion  27  of the one piece pre-molded seal  22 . 
     Accordingly, the downwardly facing circular ledge  32  of the toggle lever  20  provides a seal guard that engages and captures the upwardly facing circular inner rim  30  of the one piece pre-molded seal  22 , the downwardly facing circular ledge  36  of the switch cover  18  provides a seal guard that engages and captures the upwardly facing circular outer rim  34  of the one piece pre-molded seal  22 , and the upwardly facing circular ledge  40  of the toggle lever  20  provides a seal guard that engages and captures the downwardly facing circular inner rim  38  of the one piece pre-molded seal  22 . These seal guards enhance the sealing capability of the one piece pre-molded seal  22 . 
     The switch cover  18  and the toggle lever  20  have matching pin receiving holes  44  and  46 , respectively, that receive the pin  24 . The pin  24  acts as a pivot for the toggle lever  20 . Moreover, as shown in FIGS. 3,  4 , and  6 , the planar portion  25  of the one piece pre-molded seal  22  has a ridge  48  that is pressed into a matching recess  50  of the switch cover  18  when the toggle lever subassembly  12  and the switch subassembly  14  are joined together. 
     During assembly, the toggle lever  20  is pushed through the one piece pre-molded seal  22 , and the toggle lever  20  and the one piece pre-molded seal  22  are inserted through the switch cover  18  until the matching pin receiving holes  44  and  46  in the switch cover  18  and the toggle lever  20  align. 
     In this position, the upwardly facing circular inner rim  30  of the one piece pre-molded seal  22  engages the downwardly facing circular ledge  32  of the toggle lever  20 , the upwardly facing circular outer rim  34  of the one piece pre-molded seal  22  engages the downwardly facing circular ledge  36  of the switch cover  18 , and the downwardly facing circular inner rim  38  of the one piece pre-molded seal  22  engages the upwardly facing circular ledge  40  of the toggle lever  20 . 
     The pin  24  is then pushed through the matching pin receiving holes  44  and  46  and the one piece pre-molded seal  22 , and is suitably pressed in or otherwise fastened to the switch cover  18 . Accordingly, the toggle lever subassembly  12  is formed as shown in FIGS. 2 and 5. The toggle lever subassembly  12  is applied to the switch subassembly  14  such that the toggle lever  20  extends into the switch case  16  to engage the switch housed therein as shown in FIG.  5 . The upper outwardly facing quadrilateral rim  26  of the switch case  16  presses the ridge  48  of the planar portion  25  of the one piece pre-molded seal  22  into the matching recess  50  of the switch cover  18  as the toggle lever subassembly  12  and the switch subassembly  14  are joined together such as by the use of rivets, adhesive, or other fasteners. 
     The use of the one piece pre-molded seal  22  results in a less expensive assembly as compared to assemblies that require the seal to be over molded onto the toggle switch as is the current practice. The one piece pre-molded seal  22  not only seals the area around the toggle lever  20  and the pin  24 , but also the interface between the switch case  16  and the switch cover  18  and, thus, prevents the need for separate seals. The one piece pre-molded seal  22  is easy and inexpensive to produce and provides an effective, complete environmental seal without the use of epoxies or other sealants. 
     FIGS. 7 and 8 show an alternative embodiment of a one piece pre-molded seal  60  that can be used in the toggle switch  10 . The one piece pre-molded seal  60  does not have the planar portion  25  of the one piece pre-molded seal  22 . The one piece pre-molded seal  60  has an opening  62  to receive the toggle lever  20 . The one piece pre-molded seal  22  has an upwardly facing circular inner rim  64  that engages and is captured by the downwardly facing circular ledge  32  of the toggle lever  20 . The one piece pre-molded seal  60  also has an upwardly facing circular outer rim  66  that engages and is captured by the downwardly facing circular ledge  36  of the switch cover  18 . The one piece pre-molded seal  60  further has a downwardly facing circular inner rim (not shown, but similar to the downwardly facing circular inner rim  38  of the one piece pre-molded seal  22 ) that engages and is captured by the upwardly facing circular ledge  40  of the toggle lever  20 . 
     Accordingly, the downwardly facing circular ledge  32  of the toggle lever  20  provides a seal guard that engages and captures the upwardly facing circular inner rim  64  of the one piece pre-molded seal  60 . Also, the downwardly facing circular ledge  36  of the switch cover  18  provides a seal guard that engages and captures the upwardly facing circular outer rim  66  of the one piece pre-molded seal  60 . Moreover, the upwardly facing circular ledge  40  of the toggle lever  20  provides another seal guard that engages and captures the downwardly facing circular inner rim of the one piece pre-molded seal  60 . These seal guards enhance the sealing capability of the one piece pre-molded seal  60 . 
     If desired, an adhesive may be applied to the outer perimeter of the one piece pre-molded seal  60  in order to provide additional sealing between the one piece pre-molded seal  60  and the switch cover  18 . 
     The use of the one piece pre-molded seal  60  results in a less expensive assembly as compared to assemblies that require the seal to be over molded onto the toggle switch as is the current practice. The one piece pre-molded seal  60  seals the area around the toggle lever  20  and the pin  24 . The one piece pre-molded seal  60 , however, does not provide a seal at the interface between the switch case  16  and the switch cover  18 . A separate seal must be provided at this interface. The one piece pre-molded seal  60  is easy and inexpensive to produce and provides an effective environmental seal. 
     Certain modifications and/or alternatives of the present invention have been discussed above. Other modifications and/or alternatives will occur to those practicing in the art of the present invention. For example, as described above, the toggle lever  20  extends into the switch case  16  to engage a switch. Alternatively, the switch in the switch case  16  may have a switch operator that extends up into the switch cover  18 , in which case the toggle lever  20  may be coupled to the switch operator in the switch cover  18 . However, in this arrangement, the switch operator may be considered to be part of the toggle lever  20 . 
     Accordingly, the description of the present invention is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details may be varied substantially without departing from the spirit of the invention, and the exclusive use of all modifications which are within the scope of the appended claims is reserved.