US Patent 7506475 Multi-coil spring window counterbalance assembly

Disclosed is a multi-coil spring assembly that is mounted in the weight pocket of a vertically operating window. The multi-coil spring assembly allows the user to attach a desired number of multi-coil springs having chosen constant forces to the counterbalance connector to provide the desired amount of counterbalance force to the sash of a vertically operating window. The multi-coil spring assembly may be rotated into an interior portion of the window to permit straightforward attachment to the counterbalance connector and then retracted into the weight pocket in a recessed position for normal window operation.