Lift control mechanism and method

In combination with a lift comprising a tail gate supported by at least one hydraulic lift cylinder for causing said tail gate to undergo a translational motion upward downward as a whole and by at least one hydraulic tilt cylinder for rotationally opening and closing said tail gate,

• a method of controlling a downward movement of said tail gate in said translational motion, said method comprising the steps of:
• gradually starting said downward movement of said tail gate and gradually accelerating said tail gate in said downward movement;
• determining the position of said tail gate on real time as a one-dimensional position coordinate with respect to a reference position;
• and
• gradually decelerating said tail gate in said downward movement after said position coordinate of said tail gate passes a pre-determined value,
• the step of real-time determination comprising the step of determining the position of said tail gate on the basis of the pressure inside and the duty ratio of a valve connected to said lift cylinder.

In combination with a lift comprising a tail gate supported by at least one hydraulic lift cylinder for causing said tail gate to undergo a translational motion upward and downward as a whole and by at least one hydraulic tilt cylinder for rotationally opening and closing said tail gate,

• a method of controlling an upward movement of said tail gate in said translational motion, said method comprising the steps of:
• gradually starting said upward movement of said tail gate and gradually accelerating said tail gate in said upward movement;
• determining the position of said tail gate on real time as a one-dimensional position coordinate with respect to a reference position;
• gradually decelerating said tail gate in said upward movement when said position coordinate of said tail gate reaches a pre-determined value;
• and
• stopping said downward movement of said tail gate while decelerating,
• the step of real-time determination comprising the step of determining the position of said tail gate on the basis of the pressure inside said lift cylinder and duty ratio of a motor for driving a hydraulic pump to transport a hydraulic liquid into said lift cylinder.

In combination with a lift comprising a tail gate supported by at least one hydraulic lift cylinder for causing said tail gate to undergo a translational motion upward and downward as a whole and by at least one hydraulic tilt cylinder for rotationally opening and closing said tail gate, a method of controlling an upward movement of said tail gate in said translational motion, said method comprising the steps of:

• gradually starting said upward movement of said tail gate and gradually accelerating said tail gate in said upward movement;
• determining a start-decelerating time and a stopping time from the position and speed of said tail gate;
• beginning to gradually decelerate said tail gate in said upward movement when said start-decelerating time is reached;
• and
• stopping while decelerating said tail gate in said upward movement when said stopping time is reached,
• said time-determining step time comprising the step of determining a start-decelerating time and a stopping time on the basis of inside pressure within said lift cylinder and the duty ratio of a motor for driving a hydraulic pump to transport a hydraulic liquid into said lift cylinder.