Patent ID: 6863040

Claim:
A rocker arm capable of being rockingly driven by a cam for selectively opening and closing a valve mounted on a cylinder head of an internal combustion engine, which rocker arm comprises: an arm body prepared from a single plate metal by a press work, and having first and second ends opposite to each other, the first end of the arm body having an internally threaded hole defined therein; an adjustment screw which serves as a pivot member or a valve drive member, the adjustment screw being threaded into the internally threaded hole in the first end of the arm body with one end portion of the adjustment screw protruding outwardly from the first end of the rocker arm; and the adjustment screw being fixed relative to the arm body by means of a structure selected from the group consisting of a first structure in which two nuts are threaded onto such one end portion of the adjustment screw in overlapping relation with each other, a second structure in which a flanged nut is threaded onto such one end portion of the adjustment screw, and a third structure in which a nut is threaded onto such one end portion of the adjustment screw with a washer intervening between such nut and the first end of the arm body, wherein the arm body has a generally inverted U-sectioned configuration including a pair of opposite side walls and a connecting wall bridging between the opposite side walls, the internally threaded hole is defined in a first end portion of the connecting wall of the arm body, and respective portions of mutually confronting inner surfaces of the opposite side walls have helical partial threads therein in continuity with an internally helically extending thread of the internally threaded hole, to threadingly receive the adjustment screw.