Abstract: A hinge mechanism (200) for a portable electronic device (100) is provided. The hinge mechanism includes a first shaft (202) that is capable of rotating about a first axis (206). The hinge mechanism also includes a second shaft (204) that is capable of rotating about a second axis (208), wherein the second axis in substantially parallel to the first axis. A link (210) connects the first shaft and the second shaft, wherein the link enables the first shaft and the second shaft to rotate in opposite directions.

Abstract: A block and tackle balance system (10), contained within a spring cover (12) extending for the full length of a jamb liner (11), includes a guide (30) that directs a cord (25) through an angled course as it passes from the balance (20), through a hole (13) in the spring cover, to a support that moves up and down with a sash (15) outside the spring cover. The passing of the cord through the angled course in the guide produces load-related friction that helps prevent hop and drop of the sash. Guide (30) also preferably supports an end of the balance within the spring cover, and a support (50, 60) on the free end of cord (25) preferably engages sash (15) automatically as the sash assembled between a pair of jamb liners (11).

Abstract: 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.

Abstract: This invention relates to a window sash balance of the coil spring and cord type in which a friction drag element is in frictional contact with multiple lengths of loops of said cord.