Patent ID: 6026755
Filing Date: 2000-02-22
Classification: A47B

Abstract:
In a counterbalance apparatus, the improvement which comprises:(a) a first member defining a longitudinal axis and having opposed ends with at least one wall between the ends;(b) a second member slidably mounted along the first member so as to be along the longitudinal axis and having opposed ends with at least one wall between the ends of the second member;(c) a pair of first cam surfaces located on the wall of the first member such that one first cam surface is a mirror image of the other first cam surface on opposed sides of the longitudinal axis;(d) a pair of second cam surfaces located on the wall of the second member such that one second cam surface is a mirror image of the other second cam surface on opposed sides of the longitudinal axis wherein each of the first cam surfaces of the pair of first cam surfaces defines oppositely inclined paths relative to each of the respective second cam surfaces of the pair of second cam surfaces and wherein with the first and second members in an extended position, each of the first cam surfaces of the pair of first cam surfaces is spaced apart from each of the respective second cam surfaces of the pair of second cam surfaces with a space between them in a plane perpendicular to a plane formed by the wall of the first member and wherein each of the respective first and second cam surfaces are located one above the other along the longitudinal axis;(e) a pair of cam followers positioned adjacent and in contact with the pairs of first and second cam surfaces in the space between each of the first and the second cam surfaces and which move in the oppositely inclined paths defined by the first and second cam surfaces; and(f) a resilient member with opposed ends and connected at one end to the pair of cam followers and at the other end to the second member so that the first and second members are biased in the extended position and so that when the resilient member is compressed, the cam followers move along the oppositely inclined paths of the first and second cam surfaces as the first and second members are moved together to provide a counterbalance for a weight on one of the opposed ends of the first and second members.