Mechanism for suppressing oscillations of mobile cranes.

摘要

According to the oscillation suppressing mechanism for a mobile type crane of the present invention, when a mode selection switch selects an operation mode and a detected value (H) by a boom position detecting means (71) is smaller than a lower limit value of an appropriate travelling range of (of H1 to H2); a change-over valve (46) for replenishment capable of changing over the position of an auxiliary pressure oil source (61) selectively to a communicating position for communication of the auxiliary pressure oil source (61) with a first oil chamber (51) of a boom raising and lowering hydraulic cylinder (50) and a communication cutting-off position is shifted to the communicating position by a control means to supply a predetermined amount of pressure oil to the first oil (51) chamber of the hydraulic cylinder (50). <IMAGE>