Powered surgical handpiece with membrane switch

A surgical handpiece, said handpiece comprising:

• a housing, said housing being shaped to define a main cavity and a switch cavity that is separate from the main cavity, wherein the switch cavity extends inwardly from an outer surface of said housing and the main cavity and the switch cavity are separated by an inner wall of said housing;
• a power consuming-energy producing unit located in the main cavity of said housing;
• and
• a switch assembly, said switch assembly including:
• a circuit layer seated in the switch cavity, said circuit layer having an outwardly directed outer surface, at least one pair of spaced-apart conductive contact pads formed on the outer surface;
• an insulating layer formed of insulating material disposed over the outer surface of said circuit layer, said insulating layer being formed to define an opening that subtends said conductive pads of said circuit layer and a channel that extends from the opening;
• a dome formed from rigid flexible, conductive material that is seated in the opening of said insulating layer so as to be in contact with the outer surface of said circuit layer, said dome having a normal state in which said dome is spaced from at least one said contact pad and a flexed state in which said dome electrically connects said contact pads together;
• a cover layer disposed over said insulating layer and said dome so as to encase said dome in the opening of said insulating layer wherein said cover layer extends over the channel formed in said insulating layer and is formed to have a vent hole in communication with the channel;
• a keypad formed of flexible, electrically insulating material that is fitted to an outer surface of said housing so as to extend over the switch cavity, said keypad being formed to have a button that is aligned over said dome;
• and
• a bezel plate formed of rigid material that is disposed over said keypad and that is secured to said housing, said bezel plate being formed with an opening through which said keypad button extends and wherein said keypad is compressed between said housing and said bezel plate so that said keypad forms a seal between said housing and said bezel plate.

A surgical handpiece, said surgical handpiece comprising:

• a housing, said housing having a switch cavity that extends inwardly from an outer surface of said housing and a recess that is located around the switch cavity, wherein the switch cavity and the recess each have a depth and the depth of the recess is less than the depth of the switch cavity;
• a power consuming-energy producing unit disposed in said housing in a space separate from the switch cavity;
• a bezel plate secured to an outer surface of said housing so as to extend over the switch cavity wherein said bezel plate abuts an outer surface of said housing adjacent the recess and said bezel plate is formed with an opening;
• a keypad formed of electrically insulating, flexible material that is located between said housing and said bezel plate, wherein said keypad is shaped to have:
• a lip that extends around an outer perimeter of said key pad, said lip being shaped to seat in the recess of said housing;
• and a button, said button being positioned to extend through the opening in the bezel plate, and said housing, said bezel plate and said keypad are collectively dimensioned so that when said bezel plate abuts said housing, said lip is compressed between said housing and said bezel plate so that said keypad lip forms a seal around the switch cavity;
• a switch plate disposed in the switch cavity of said housing, said switch plate having:
• substrate with an outer surface;
• a pair of spaced apart contact pads formed on the outer surface of said substrate, said contact pads being aligned with said keypad button;
• a dome formed from flexible, conductive material that is disposed over said contact pads, said dome having a normal state in which said dome is spaced apart from at least one said contact pad and a flexed state in which said dome physically abuts and is electrically connected to both said contact pads, wherein said dome is in registration with said keypad button so that, upon depression of said button, said button forces said dome from the normal state to the flexed state;
• and a cover disposed over said substrate and said dome, said cover having a vent port in air communication with an interstitial space between the substrate outer surface and said dome.