Abstract: A haulage vehicle includes a vessel 3, hoist cylinders 10, a control valve device 16 that controls a supply or discharge of pressurized oil to or from the hoist cylinders 10, a controller 35, and a tilt angle detector 31 that detects a tilt angle of the vessel 3. The controller 35 compares a down assist performing angle, which is a tilt angle preset to determine whether negative pressure control processing needs to be performed for offsetting a force applied in a direction that would cause the hoist cylinders 10 to extend, with the detected tilt angle and, if the detected tilt angle is determined to be equal to or greater than the down assist performing angle, outputs a control valve signal to the control valve device 16 so that the valve is opened to forcibly discharge pressurized oil from the hoist cylinders 10.

Abstract: A haulage vehicle includes a vessel 3, hoist cylinders 10, a control valve device 16 that controls a supply or discharge of pressurized oil to or from the hoist cylinders 10, a controller 35, and a tilt angle detector 31 that detects a tilt angle of the vessel 3. The controller 35 compares a down assist performing angle, which is a tilt angle preset to determine whether negative pressure control processing needs to be performed for offsetting a force applied in a direction that would cause the hoist cylinders 10 to extend, with the detected tilt angle and, if the detected tilt angle is determined to be equal to or greater than the down assist performing angle, outputs a control valve signal to the control valve device 16 so that the valve is opened to forcibly discharge pressurized oil from the hoist cylinders 10.

Abstract: A parking brake control device for a transport vehicle is attached to a vehicle body including a parking brake (17) of a negative control type for maintaining a state in which rotation of wheels is stopped, the parking brake control device including a control unit (32) for controlling movement of a spool (21) for magnetizing or demagnetizing a solenoid valve (25) to release or actuate the parking brake (17). The control unit (32) includes a stop determining section (33) that determines whether the vehicle body stops traveling, an actuation command section (34) that actuates the parking brake (17) when the stop determining section (33) determines that the vehicle body is stopped, and a release command section (35) that releases the parking brake (17) after elapse of a preset setting time after the actuation of the parking brake (17) is started by the actuation command section (34).

Abstract: A body hoisting state display device to be mounted on a dump truck includes: an angle detection unit that detects a rotation angle of the body with respect to the frame; a seating detection unit that detects whether or not the body is seated on the frame; a calculation unit that causes an inclination angle of the body at which the body is rotated with respect to the frame from a seated state of the body to be calculated, based on the rotation angle detected by the angle detection unit, as a ratio to an angle of a rotatable range that is defined between the seated state and a state in which the hydraulic cylinder is stopped at the position short of the position at which the hydraulic cylinder is extended to the maximal extent; and a display control unit that causes the ratio of the inclination angle of the body that is calculated by the calculation unit to be displayed on a display screen.

Abstract: A body hoisting state display device to be mounted on a dump truck includes: an angle detection unit that detects a rotation angle of the body with respect to the frame; a seating detection unit that detects whether or not the body is seated on the frame; a calculation unit that causes an inclination angle of the body at which the body is rotated with respect to the frame from a seated state of the body to be calculated, based on the rotation angle detected by the angle detection unit, as a ratio to an angle of a rotatable range that is defined between the seated state and a state in which the hydraulic cylinder is stopped at the position short of the position at which the hydraulic cylinder is extended to the maximal extent; and a display control unit that causes the ratio of the inclination angle of the body that is calculated by the calculation unit to be displayed on a display screen.

Abstract: A parking brake control device for a transport vehicle is attached to a vehicle body including a parking brake (17) of a negative control type for maintaining a state in which rotation of wheels is stopped, the parking brake control device including a control unit (32) for controlling movement of a spool (21) for magnetizing or demagnetizing a solenoid valve (25) to release or actuate the parking brake (17). The control unit (32) includes a stop determining section (33) that determines whether the vehicle body stops traveling, an actuation command section (34) that actuates the parking brake (17) when the stop determining section (33) determines that the vehicle body is stopped, and a release command section (35) that releases the parking brake (17) after elapse of a preset setting time after the actuation of the parking brake (17) is started by the actuation command section (34).