Abstract: When a rotary drive source on a body is energized, a drive pulley is rotated, and the rotary drive power from the drive pulley is transmitted to a driven pulley by a drive power transmitting belt. A slotting mechanism integrally coupled to the driven pulley is rotated and inserted into a larger end hole defined in a connecting rod. A cutting plate of the slotting mechanism forms a first slot having a substantially rectangular concave cross section in the inner circumferential surface of the larger end hole and then a second slot having a substantially rectangular concave cross section in the inner circumferential surface of the larger end hole at a position facing the first slot across the axis of the connecting rod. The first and second slots have a symmetrical shape.

Abstract: A preload is applied to a wedge pressed in between a pair of spreaders by a preloading mechanism to press the spreaders against an inner surface of a joint hole defined in a larger end of a connecting rod. While the spreaders are pressed against the inner surface of the joint hole, a movable table with weights placed thereon is caused to drop into impingement against a flange coupled to an end of a shaft. The shaft is pulled downwardly to apply an impact load to the wedge, which is coupled to the shaft, in the direction in which the wedge is pressed in, thereby fracturing the larger end into a cap and a rod.

Abstract: When a rotary drive source on a body is energized, a drive pulley is rotated, and the rotary drive power from the drive pulley is transmitted to a driven pulley by a drive power transmitting belt. A slotting mechanism integrally coupled to the driven pulley is rotated and inserted into a larger end hole defined in a connecting rod. A cutter of the slotting mechanism forms a first slot having a substantially V-shaped cross section in the inner circumferential surface of the larger end hole and then a second slot having a substantially V-shaped cross section in the inner circumferential surface of the larger end hole at a position facing the first slot across the axis of the connecting rod. The first and second slots have a symmetrical shape.