Patent ID: 6957683
Filing Date: 2005-10-25
Classification: E06B,Y10T

Abstract:
1. A cover system, comprising: a base; an extendible cover mounted to the base and having a free end depending from the base; a rail mounted proximate the free end of the extendible cover; pulley means mounted proximate the base for rotation; and lift cord means wound around the pulley means and attached to the rail; a spring drive system, comprising: the extendible cover thereby being supported by the spring drive system via the lift cord means and being oriented such that moving the rail back and forth retracts and extends the extendible cover along a path between open and closed positions, and whereby the associated supported weight of the extendible cover varies along said path; the force of the spring drive, the ratio of the variable ratio cord transmission and the ratio of the gear transmission being selected for counterbalancing the varying supported weight of the extendible cover along said path; and the spring drive system maintaining the extendible cover at rest along said path.