| 摘要 |
An improved counterbalance hinge assembly has a bias spring and uniquely shaped cam for counterbalancing inherently nonlinear forces represented by pivoting loads such as fold up wall type beds, desks, and the like. A cable attached to the spring wraps progressively around the cam surface as the bed or other load is pulled out from the wall, thereby compressing the spring. The effective radius of the cam at a given point is designed in conjunction with the peripheral extent of the cam surface up to that point, to give the desired counterbalancing force as a function of the angular position of the load. In the preferred embodiment, the effective radius is thus smaller with the bed in its horizontal position than with the bed in its vertical position. Additionally, a small offset angle may be provided in the counterbalancing mechanism near the vertical position, to aid in moving the load to and from its stored position. |
