| 摘要 |
Apparatus for counterbalancing a vertically movable element of a machine includes an air cylinder attached to the movable element on the axis of movement and having a small axial opening at its upper end. A piston located in the air cylinder is attached to a fixed machine element by a nonelastic, flexible member such as a thin, nylon-jacketed wire passing through the axial opening in the cylinder. Air under pressure sufficient to counterbalance the weight of the movable element is supplied to the space between the piston and the axial opening in the cylinder. The flexible member makes the counterbalancing assembly relatively insensitive to misalignment and vibration. Air is permitted to leak around the piston to reduce friction and to relieve pressure buildup during downward movement. In another embodiment, the air cylinder is attached to the fixed machine element.
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