Bonding washer
A bonding washer for making electrical connection between two metal pieces that are to be mechanically fastened together. The washer, to be interposed between the two metal pieces, is constructed so as to fasten to one of the pieces before the two pieces are joined. Teeth on the washer, positioned at right angles to the plane of the washer, are forced into each of the two metal pieces when the fastener is tightened, making electrical connection between the two metal pieces.
1. A bonding washer for use with a first metal piece, a second metal piece, and a fastener which rigidly holds said first metal piece to said second metal piece comprising:
a) a metal body member,
b) said metal body member having a first set of teeth, of number one or more, said first set of teeth extending at substantially right angles to said metal body member, said first set of teeth also extending at substantially right angles to the plane at which said first set of teeth will contact said first metal piece,
c) said metal body member having a second set of teeth, of number one or more, said second set of teeth extending at substantially right angles to said metal body member, said second set of teeth also extending at substantially right angles to the plane at which said second set of teeth will contact said second metal piece,
whereby when said fastener is tightened, said first set of teeth forcibly embed into said first metal piece, thereby making an airtight electrical contact with said first metal piece, and said second set of teeth forcibly embed into said second metal piece, thereby making an airtight electrical contact with said second metal piece, thereby in turn making electrical connection between said first metal piece and said second metal piece,
wherein each of said first and second sets of teeth has a cross-sectional height greater than its base cross-sectional thickness;
d) said metal body member having a clearance hole for said fastener,
wherein said fastener is inserted through said clearance hole of said bonding washer and thereafter tightened; and
e) said metal body member having a plurality of fingers extending at substantially right angles to the plane of said metal body member, said plurality of fingers located near the edge of said clearance hole,
whereby when said plurality of fingers are pushed into a hole in said first metal piece, said fingers exert a spring force on said hole, allowing said bonding washer to retain its position while said hole of said first metal piece is aligned with a hole in said second metal piece with said bonding washer between said first and second metal pieces, and wherein said fastener is inserted through said first metal piece and said bonding washer and said second metal piece and thereafter tightened.
2. The bonding washer of claim 1 , where the number of fingers is four.
3. A method of forming a bonding washer for use with a first metal piece, a second metal piece, and a fastener which rigidly holds said first metal piece to said second metal piece comprising:
a) providing a metal body member;
b) forming a first set of teeth, of number one or more, in a first region of said metal body member, said first set of teeth formed to extend at substantially right angles to said metal body member, said first set of teeth also formed to extend at substantially right angles to the plane at which said first set of teeth will contact said first metal piece;
c) forming a second set of teeth, of number one or more, in a second region of said metal body member, said second set of teeth formed to extend at substantially right angles to said metal body member, said second set of teeth also formed to extend at substantially right angles to the plane at which said second set of teeth will contact said first metal piece;
d) folding said metal body member to align each of said second set of teeth to directly oppose a corresponding one of said first set of teeth, whereby when said fastener is tightened, said first set of teeth forcibly embed into said first metal piece, thereby making an airtight electrical contact with said first metal piece, and said second set of teeth forcibly embed into said second metal piece, thereby making an airtight electrical contact with said second metal piece, thereby in turn making electrical connection between said first metal piece and said second metal piece; and
e) forming a plurality of fingers in said metal body member, said fingers formed to provide a spring force to retain said bonding washer in position.
4. The method of claim 3 wherein said fingers are formed with a twist to provide said spring force.