Patent ID: 6378446
Filing Date: 2002-04-30
Classification: A47B

Abstract:
In a counterbalance apparatus, the improvement which comprises:(a) a first tubular member defining a longitudinal axis and having a first end and a second end with at least one wall between the ends which forms the tubular member having an inner cavity, wherein a first cam surface is provided on the wall in the inner cavity and is inclined with respect to the longitudinal axis of the first tubular member; (b) a second tubular member slidably mounted in the first tubular member so as to be along the longitudinal axis and having a first end and a second end and at least one wall between the ends forming an inner cavity, wherein a second cam surface is provided on at least one wall in the inner cavity of the second tubular member along the axis and is inclined with respect to the longitudinal axis of the first tubular member, wherein the first and second cam surfaces are oppositely inclined with respect to the longitudinal axis and wherein at least one of the second or first tubular members is movable along the longitudinal axis relative to the other of the tubular members to move the tubular members together; (c) cam follower means mounted on and between the first and second cam surfaces, wherein the cam follower means moves on both cam surfaces simultaneously as the tubular members are moved together; and (d) resilient means having opposed ends and mounted along and around the longitudinal axis of the tubular members so as to bias the tubular members apart and wherein the resilient means is shortened in length between the ends when the tubular members are moved together.