Movement No. 130 demonstrates a power shear mechanism for cutting iron plates and similar heavy materials. The shear consists of an upper jaw and a fixed lower jaw. The upper jaw is a lever with a long weighted arm on one side and the cutting blade on the other. When the cam is not in contact, the weight of the long arm pulls that side down, which raises the cutting blade end — holding the jaws open and ready to receive the workpiece. As the cam rotates and its lobe contacts the long arm, it pushes that arm down against the weight, which pivots the upper jaw and drives the cutting blade forcefully downward onto the lower jaw, shearing through the material. When the cam lobe passes, the weight of the long arm automatically returns the blade to the open position. This self-resetting action allows continuous, rhythmic cutting with each revolution of the cam, making it ideal for repetitive plate-cutting operations in metalworking.
130. Shears for cutting iron plates, etc. The jaws are opened by the weight of the long arm of the upper one, and closed by the rotation of the cam.