A lift attachment system for providing adjustment such as lifting and lower to various attachments being towed by a vehicle. The system generally includes a base frame which is removably connected to a vehicle, such as at its rear frame. A support frame is pivotally connected to the base frame. An actuator is connected between the support frame and the base frame such that the support frame may pivotally adjust with respect to the base frame. The support frame includes a width-adjustable attachment mount which is adapted to removably receive one of a plurality of different attachments. By removably connecting the attachment to the support frame, the attachment may be pivotally adjusted (such as lifted or lowered) via activation of the actuator. By connecting the base frame to a vehicle, one may adjust an attachment while in use on a vehicle to improve efficiency and prevent constant manual adjustments.

A work machine according to the present invention includes a manual operating tool configured to operate a hydraulic actuator; an operation amount detector configured to detect an operation amount of the manual operating tool; a hydraulic pump configured to generate a hydraulic pressure to be supplied to the hydraulic actuator; an electric pump motor configured to change an output characteristic of the hydraulic pump in response to a rotary force to be given to the hydraulic pump; a motor load detector configured to detect a motor load of the pump motor; and a pump motor controller configured to determine a necessary output characteristic based on the operation amount and the motor load and control the pump motor based on the output characteristic.

A work machine according to the present invention includes a manual operating tool configured to operate a hydraulic actuator; an operation amount detector configured to detect an operation amount of the manual operating tool; a hydraulic pump configured to generate a hydraulic pressure to be supplied to the hydraulic actuator; an electric pump motor configured to change an output characteristic of the hydraulic pump in response to a rotary force to be given to the hydraulic pump; a motor load detector configured to detect a motor load of the pump motor; and a pump motor controller configured to determine a necessary output characteristic based on the operation amount and the motor load and control the pump motor based on the output characteristic.

A mechanical system attaches to a tractor and, upon activation of a hydraulic ram, rotates implement-engaging implement lift hooks to rotate an attached agricultural implement upwards towards 90 degrees for inspection and maintenance. The system can be secured in its raised and rotated position via a locking pin. The implement is returned to its original position through removal of the locking pin, reversal of the hydraulic ram and disconnection of the implement lift hooks.

A mechanical system attaches to a tractor and, upon activation of a hydraulic ram, rotates implement-engaging implement lift hooks to rotate an attached agricultural implement upwards towards 90 degrees for inspection and maintenance. The system can be secured in its raised and rotated position via a locking pin. The implement is returned to its original position through removal of the locking pin, reversal of the hydraulic ram and disconnection of the implement lift hooks.

Provided is, as an operating mechanism for adjusting a biasing spring from outside a valve block, a mechanism that achieves stable flow rate adjustment while avoiding a structure that generates backlash. The operating mechanism includes: a spool 40a configured to adjust a flow rate of an oil passage disposed in a valve block 30; a solenoid 5 configured to move the spool 40a; a biasing spring 50 biasing the spool 40a in such a direction as to return the spool 40a to an initial position thereof, at least one initial pressure adjustment mechanism 6 configured to adjust a biasing force of the biasing spring 50. The at least one initial pressure adjustment mechanism 6 includes: a spring bearing member 51; an operating body 60 including an operation input portion 61 operable from outside the valve block 30 and an operation output portion 62 located inside the valve block 30 and in contact with the spring bearing member 51, and the at least one initial pressure adjustment mechanism 6 is configured to adjust the biasing force in response to the operation input portion 61 being operated to move the spring bearing member 51 in first directions in which the spool moves.

Provided is, as an operating mechanism for adjusting a biasing spring from outside a valve block, a mechanism that achieves stable flow rate adjustment while avoiding a structure that generates backlash. The operating mechanism includes: a spool 40a configured to adjust a flow rate of an oil passage disposed in a valve block 30; a solenoid 5 configured to move the spool 40a; a biasing spring 50 biasing the spool 40a in such a direction as to return the spool 40a to an initial position thereof, at least one initial pressure adjustment mechanism 6 configured to adjust a biasing force of the biasing spring 50. The at least one initial pressure adjustment mechanism 6 includes: a spring bearing member 51; an operating body 60 including an operation input portion 61 operable from outside the valve block 30 and an operation output portion 62 located inside the valve block 30 and in contact with the spring bearing member 51, and the at least one initial pressure adjustment mechanism 6 is configured to adjust the biasing force in response to the operation input portion 61 being operated to move the spring bearing member 51 in first directions in which the spool moves.