Conicity angle measurement for lateral faces of piston - involves plate giving horizontal surface and reference plane

摘要

The instrument measures the angle of conicity for high performance pistons. By making radial cuts in the piston, the lateral faces converge toward one another and to the axis of the conical segment. The instrument consists of a plate (12) giving a horizontal surface and reference plane (14). A support (20) mounted on the plate carries a measuring wedge (22) pivoting on an axis (24). The lower edge of the wedge is at a predetermined angle. A dial (30) is mounted on the support, and is connected to a vertical needle (32) which is in contact with the upper surface of the wedge. A conical segment of piston (36) with truncated lateral faces (38, 40) is slid along the reference plane until the face (38) is in contact with the lower surface of the wedge, giving a reading on the dial. The angle formed between the face (40) and the reference plane is similarly measured, and hence the angle of conicity is determined.