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US 5,054,162 AGranted
Constant force compensation for power spring weight balance
AssigneeSchlegel Corporation
InventorTracy G. Rogers
Life of this patent
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AssigneeSchlegel Corporation
InventorTracy G. Rogers
Estimating the term…
An apparatus for offsetting a constant force over a range of movement, includes a power spring or clock spring, defined by a length of resilient material wound in a spiral, the opposite ends of which are attached relative to one of the force and a fixed point, and to a pulley. The pulley is substantially coaxial with the spring and has a rounded outer contour defining a progressively varying slope proceeding axially along the pulley. A flexible cord wraps around the pulley and leads to the other of the force and the fixed point. The opposite (inner and outer) ends of the spring can be mounted such that the inner end of the spring is fixed relative to the fixed point and the outer end of the spring is attached to the pulley. The constant force can be the weight of a window sash, movable vertically in a frame. The rounded outer contour of the pulley defines a curve corresponding to an increase in torque of the spring with displacement, due to decrease in radius of the spring and decrease in active length of the spring with binding of inner wraps of the spiral.
A counterbalance apparatus for offsetting a constant force between two points of reference, over a range of movement, the points of reference respectively defining a point of attachment to the force and a fixed point, the apparatus comprising:
A counterbalance apparatus for offsetting the weight of a body movable vertically relative to a fixed point, the body and the fixed point defining two points of reference, the counterbalance, comprising:
A sash apparatus, comprising:
Dependencies are inferred from the claim text.