| 摘要 |
The invention contemplates an improved grapple or grab-bucket construction of the double-acting hydraulically activated variety, wherein the normal bucket-open position is determined by a stiffly yieldable abutment which yields to permit a short further energy-absorbing bucket-opening displacement in the presence of the mechanical shock encountered upon dropping the open grab bucket onto a relatively hard base to be excavated. The short further shock-induced displacement elevates hydraulic pressure in the actuation system, which elevated pressure is vented by a relief valve in common with the hydraulic actuators of all buckets in the grapple.
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