Patent ID: 9663986
Date: 2017-05-30
CPC Classifications: E06B

Claim:
1. A spring counterbalance apparatus comprising: a shade system with a shade system torque profile, the shade system having a drive shaft; a first spring system connected with the drive shaft wherein the first spring system is a standard wound spring system having a spring storage spool and a spring drive spool; a second spring system connected with the drive shaft wherein the second spring system is a reverse wound spring system having a spring storage spool and a spring drive spool; wherein the shade is movable between an open position and a closed position; wherein in combination the first spring system and the second spring system produce a dynamic counterbalance torque profile because as the shade is lowered an increasing amount of the shade hangs from the head rail; wherein the dynamic counterbalance torque profile is slightly higher than the shade system torque profile; wherein in combination the standard wound spring of the first spring system and the reverse wound spring of the second spring system produce a dynamic counterbalance torque profile as the shade moves between the open position and the closed position; wherein when the shade moves between the open position and the closed position the dynamic counterbalance torque profile produced by the standard wound spring of the first spring system and the reverse wound spring of the second spring system closely approximate the dynamic weight profile of the shade thereby facilitating manual movement as well as motorized movement; wherein an axis of rotation of the spring drive spool of the first spring system and an axis of rotation of the spring drive spool of the second spring system are aligned; and wherein an axis of rotation of the spring storage spool of the first spring system and an axis of rotation of the spring storage spool of the second spring system are aligned.