Patent ID: 7556005

Claim:
An automatic tappet clearance adjusting apparatus for adjusting a clearance between a valve and an adjustment screw in an engine, in which the valve that is closed by a spring is opened by being pressed by an adjustment screw on a distal end of a rocker arm, comprising: an adjustment unit for advancing and retracting said adjustment screw from a distal end of said rocker arm to adjust a projection of the adjustment screw; a torque detector for detecting a torque to rotate said adjustment screw; and a control mechanism for controlling said adjustment unit based on a torque value measured by said torque detector, wherein said control mechanism successively detects said torque value applied to retract said adjustment screw to close said valve from a state in which said valve is open, and detects, as a reference point, a point of intersection of a first straight line, which corresponds to a time zone immediately before an inflection point at which a differential value of said torque value changes, with a second straight line which corresponds to a time zone immediately after the inflection point, and then retracts said adjustment screw by a set quantity based on said clearance from said reference point.