Measures to secure a patent for improvements in the above have been taken by Wil liam Van Anden, of Poughkeepsie. N. Y. In this invention there are two distinct improvements. The first enables the workman to regulate the force with which the hammer descends upon the anvil, and the second is a su-i perior manner of placing the friction rollers which receive the action of the cams. The hammer shaft is attached to a collar which works loosely around a shaft provided with a spring, whose duty is to force down the hammer, which it does with more or less energy according to its adjustment. When the cam shaft is made to rotate, the hammer shalt is elevated by the action of the cams against the friction rollers, which are placed in a frame capable of vibration, so as to relieve the cams after their highest points have performed their functions. A third cam, acting through the medium of a lever and set-screw, causes a spring to bear against the hammer shaft when the downward motion is to take place.