| 摘要 |
A dual hand lever control for actuating the shipper rod which controls a hydraulic press valve in response to the simultaneous depression of both hand levers. A cross bar, centrally attached to the lower end of the shipper rod, carries a pivotally mounted, bell-crank at each of its opposite ends. Each of these bell cranks is movable with the shipper rod and also is pivotable along a secondary path to permit movement of one of its bell-crank arms into and away from an intermediate position in the path of movement of its cooperating hand lever. A linking bar is pivotally connected at each of its ends to the other bell-crank arm of each bell crank. Actuation of a single control lever exerts a force on its bell crank to pivot the bell crank along its secondary path without moving the shipper rod and, through the linking bar, to withdraw the other bell crank from the path of movement of the hand lever. When both hand levers are operated, these forces are exerted on both bell cranks but are cancelled by the linking bar to permit actuation of the shipper rod.
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