Abstract: A ladder unit for climbing up and down a construction machine, capable of stabilizing a ladder in a position of descent thereof and that of storage thereof, facilitating an operator's actions to climb up and down the construction machine, and preventing the ladder from projecting toward circumferential parts and being thereby broken. Mechanisms for locking the ladder in the position of descent thereof are provided. The ladder locking force of these locking mechanisms is rendered releasable from the ladder in a position on the construction machine. Mechanisms for locking the ladder in its storage position are also provided.

Abstract: The present invention is a control device for a variable displacement hydraulic pump by which the absorption horsepower of the hydraulic pump increases with excellent responsiveness and ON/OFF operations of a cut-off control of the maximum pressure can be selected. To this end, a hydraulic pump (2), a slow return valve (25) and a switching valve (24) placed parallel to each other in a flow path connecting a servo piston (4) and a servo valve (5); a solenoid valve (26), for controlling the pilot pressure of the switching valve (24); and an ON/OFF operation selectable selector (30), connected to a control device (10), are included; and the controlling device (10) outputs a command signal to the solenoid valve (26) when the selector (30) is switched ON to lower the operation speed of the swash plate angle of the hydraulic pump (2).