| 摘要 |
In a power shovel having a crowd system for crowding and retracting a dipper and a hoist system for hoisting and lowering such a dipper, a system for limiting the motion of the dipper generally comprising means operatively interconnecting a crowd componment movable between predetermined crowd and retract limits and crowd control lever responsive to a movement of the crowd component between the pedetermined limits of movement thereof for increasingly biasing the crowd control lever steadily away from an operative position thereof, as the crowd component approaches one of the predetermined limits of movement thereof, means operatively interconnecting a hoist control lever and a hoist component movable between predetermined upper and lower limits responsive to a movement of the hoist component between the limits of movement thereof for increasingly biasing the hoist control lever steadily away from an operative position thereof as the hoist component approaches one of the predetermined limits of movement thereof, and means operatively connected to the hoist control lever responsive to predetermined angular displacements of an upper frame of the shovel relative to a lower frame thereof for conditioning the hoist control lever biasing means to advance in time the biasing of the hoist control lever away from the lowering position thereof. |
