Patent ID: 8113998

Claim:
A device comprising: a holding assembly operable by a user, said user to operate said holding assembly at one end; counter-force unit comprising two or more zones having each different spring coefficient; substantially vertical supporting means to support said holding assembly and said counter-force unit; and an insert, insertable into a column and attachable to said column at a desired amount of insertion wherein said counter-force unit is adapted to provide adjustable counter-force to downwards movement of said holding assembly; wherein the movement of said one end of said holding assembly downwards in response to an applied force by said user is along a curve path having a radius that changes as said holding assembly moves; wherein the movement of said one end of said holding assembly downwards activates said zones in an orderly manner, a first zone first, wherein said counter-force unit comprises a set of leaf springs attached at the top of said insert, said set of leaf springs comprising at least two leaf springs attached to one another side-by-side so that one spring only partially overlaps its adjacent leaf spring, wherein the amount of partial overlapping of at least one said leaf spring over its adjacent leaf spring is adjustable, and wherein said holding assembly is attached at the upper end of said leaf spring set to allow applying of bending force to said leaf spring set.