Powered mine support frame shifter - shifting rod hinged to beam and base unit, two cylinder shifting action

摘要

Shifter for powered mine supports formed from two successive frames clamped to a common datum beam at the leading end. Each frame is linked to the beam through a shifter rod which is hinged at one end to the base unit of the support frame and at the other to the beam and two shifting cylinders. One cylinder is hinged to the base unit and shifting rod, the second to the beam and shifting rod. The distances between each hinge point of one such cylinder to the hinge points between the rod and base unit preferably equal but in the opposite direction the corresponding distances between the hinge points for the second cylinder completing the shifting unit.