US Patent 7407017 Locking mechanism

The present invention relates to a method of securing a shaft at any point along its substantially vertical axis of movement, wherein the method includes a locking device that is moveable with respect to the shaft. The method is characterised by the step of moving the locking device into a position wherein at least one face of the locking device mates against at least one point on the shaft so as to secure the shaft at any point along its substantially vertical axis of movement. In particular this invention relates to a method of securing a drop hammer at any point along its substantially vertical axis by use of a hydraulically controlled cam.