초록 ▼

The precise and smooth control of the hydraulic fluid supplied to a hydraulic system, such as the lifting cylinders of a turret stockpicker, under varying operating conditions includes an optical encoder on the operator\s control handle connected to an electronic control of a hydraulic pump motor, w

The precise and smooth control of the hydraulic fluid supplied to a hydraulic system, such as the lifting cylinders of a turret stockpicker, under varying operating conditions includes an optical encoder on the operator\s control handle connected to an electronic control of a hydraulic pump motor, which s initially operated at a predetermined minimum speed, and a hydraulic valve which provides the initial control of hydraulic fluid under the control of an operator\s handle. Because the pump is initially at a low speed, greater efficiency of the system is realized, an important feature in a battery operated vehicle. As the operator moves the handle from the off or neutral towards the fully open position, the hydraulic valve will open and reach its fully open position as the handle passes approximately the one-third on position. Pump motor speed is maintained at a minimum speed until the hydraulic valve is almost opened, and then the pump motor speed will be increased at a predetermined rate until its maximum speed has been obtained with the handle being almost fully on. The last few degrees of movement of the handle will not cause any further increase in hydraulic pressure or motor pump speed, but it will by-pass an SCR pump motor control circuit, thus further increasing efficiency.

대표청구항 ▼

In an apparatus for supplying a controlled hydraulic pressure and flow to a utilization device, said apparatus includes a control handle moveable through a predetermined distance, a hydraulic pump, an electric motor for driving said pump to supply hydraulic fluid under pressure, and a hydraulic valv

In an apparatus for supplying a controlled hydraulic pressure and flow to a utilization device, said apparatus includes a control handle moveable through a predetermined distance, a hydraulic pump, an electric motor for driving said pump to supply hydraulic fluid under pressure, and a hydraulic valve responsive to the position of said control handle for controlling the flow of hydraulic fluid to the utilization device, the improvement comprising means for sensing the position of said control handle, means responsive to said sensing means for controlling the speed of said pump motor, said controlling means including means for establishing and maintaining a minimum pump motor speed, and circuit means for controlling said pump motor speed as said control handle is operated in an intermediate position. A method for controlling the application of hydraulic pressure and flow from a motor driven pump through a hydraulic control valve to a utilization device in response to the position of a control handle, said method including the steps of establishing and maintaining a minimum pump motor speed, controlling said hydraulic control valve through which hydraulic pressure and flow is supplied to the utilization device by means of said handle wherein, as said handle is moved from an off to an intermediate position, said valve will progress from a fully closed position to a fully open position, and controlling said pump motor speed further to control hydraulic flow in response to movement of said handle from an intermediate position, prior to said valve becoming fully open, to an on position.