PURPOSE: To hold horizontal and stable elevation of a driver's cabin by providing a pantograph-shaped displacement enlarging mechanism, operated by a hydraulic cylinder for elevation, and a bending link mechanism which supports the driver's cab so that the cab is prevented from lowering due to the occurrence of oil leak.
CONSTITUTION: An oil pressure from a pump 101 is fed in a line 111 with the aid of a control lever 104 to expand a hydraulic cylinder 21, and simultaneously a control valve 103 is positioned in (d) through the force of a spring and feeds an oil pressure to the contraction side of a cylinder 35 through a line 113 to increase the loads of the cylinders 21 and 35. A valve 103c is shifted to a position (c) through a shattle valve 106 by means of an increased oil pressure and is connected to a line 112 through the free flow of a slow return valve 105, and the cylinder 35, serving to raise the driver's cabin, is actuated in the direction of expansion by means of a displacement enlarging mechanism. Simultaneously, the cylinder 21 is expanded to lift the driver's cabin through a top dead center to an angle, at which a stopper 28 is rendered effective, by means of a bending link mechanism 20. This enables the driver's cab to be secured without production of uneasy feeling of lowering.
NOSAKA HIROSHI
HATA SHOICHI
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