| 摘要 |
The present invention provides a spring balance assembly for use with a sash window assembly slidable within a master frame. The spring balance assembly general ly includes a plurality of stacked spring assemblies and pivot brake assembly. The spring assemblies include a coil spring and a support plate that rotatably supports the coil spring. Each coil spring has a free end, an intermediate portion, and a coiled portion, wherei n the free ends are operably connected to the pivot brake assembly. The coil springs are configured to prevent a portion of the spring from excessive bowing and making prolonged contact wit h the wall of the mounting channel to which the balance assembly is affixed. In addition, the coil springs are wound in a manner that significantly reduces the occurrence of severe bowing of the coiled portion and engagement with the channel walls. The spring balance assembly of the present invention reduces contact with the channel walls and thereby reduces any friction and the operating force. |
