| 摘要 |
The invention is a force compensation device for use in a spring balanced sash holder for a jamb liner extruded from a durable resin such as polyvinyl chloride, and having a vertical track for containing the sash. Within the vertical track in the sash plow region and running the entire length of the jamb liner is a vertical slotted channel. The lower half of the slotted channel is used to develop frictional force for compensation of spring balance forces. The invention produces its compensating force by frictionally engaging the surfaces of the slotted channel. It comprises two parts, a carrier and a clapper. The carrier supports the weight of the sash, and is supported by the balance spring. The clapper is attached to the carrier. Both the carrier and clapper have braking elements which frictionally engage the surfaces of the slotted channel of the jamb liner track. The carrier and clapper are fastened together at their lower ends but their upper ends are free to move relative to each other. The braking elements, which are integral parts of the the carrier and clapper upper ends, are urged together by a sideways force which is produced by the end of the balance spring. The end of the spring acts on an inclined surface of the carrier and on a vertical surface of the clapper to produce the sideways force.
|
