Patent ID: 7467787
Filing Date: 2008-12-23
Classification: F16F

Abstract:
1. A compression spring rod comprising a housing, a rod member, a guide member, a first bushing, and first and second compression springs; said housing having an axis, axially opposite first and second ends, an opening in said first end, and first and second chambers; said rod member positioned substantially coaxial with said housing axis and having an inner end in said housing and an outer end extending axially through said opening in said first end and outwardly of said first end of said housing, said outer end of said rod member including a mounting element; said guide member secured to a portion of said rod member located in said housing, said guide member at least partially separating said first and second chambers in said housing; said first bushing positioned at least closely adjacent to said first end of said housing, said first bushing including a central region opening designed to at least partially support said rod member during axial reciprocation in said housing between fully retracted and fully extended positions; said first and second compression springs each positioned in said second chamber of said housing and extending between said guide member and said second end of said housing, said first and second compression springs substantially coaxial with said housing axis, at least one of said first and second compression springs causing said rod member to move to a substantially fully extended position when no force along said housing axis is applied to said outer end of said rod member, at least one of said first and second compression springs in a partially compressed state when said rod member is in said fully extended position, said first spring having a different free length from said second spring, said first and second compression springs producing a generally linear spring force as said rod member over a majority of a distance said rod member moves when moving from a substantially fully extended position to a substantially fully retracted position.