Added two cams changing device,can easily switch between one step two points and three steps four points only pulling the changing spanner.At the same time,with automatic compensatory mechanism, can make the cams long life.

• 采用双凸轮切换装置，只须扳动切换扳手就可以实现，在一台机器上进行二点和四点两种线迹的切换，使凸轮的使用寿命延长，更加经久耐用。