| 摘要 |
This disclosure pertains to novel improvements in the structure of fluid operated grapples. A grapple assembly comprises a pair of jaws pivotally interconnected to a swivel head and a pair of fluid operated linear actuators pivotally interconnected to the swivel head and the jaws. The swivel head comprises a spindle portion rotatably mounted in a housing portion by upper and lower thrust bearings, the thrust bearings themselves being operatively mounted in upper and lower bearing chambers. A grapple-closing fluid source is duct-connected through the spindle portion to the lower bearing chamber and a grapple opening fluid source is duct-connected similarly to the upper bearing chamber. The extension ports of the linear actuators are duct-connected to the lower bearing chamber and the retraction ports are duct-connected to the upper bearing chamber. Fluid pressure in the lower bearing chamber imparts an upward thrust on the housing when the grapple jaws are closed or loaded and pressure in the upper bearing chamber provides a downward thrust on the housing when the grapple is open.
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