Lubrication system for large screw jack - has grease pump which is actuated every time jack reaches lowest position

摘要

The large screw jacks used in garages for raising vehicles need frequency lubrication of the lifting screw. This can be achieved by mounting a grease pump directly on the horizontal beam which supports the vehicle. The pump consists of a cylinder (10) filled with grease which is under pressure from a spring loaded piston (12). A block (9) mounted below the cylinder has a plunger (16) retained by a leaf spring (18). When the jack reaches its lowest point the plunger (16) strikes a boss (19) which forces grease out of the passage-way (17) through the non-return valve (20) and pipe (11) into the nut (8) and onto the thread of the screw (7). When the jack is raised the leaf spring withdraws the plunger ready for the next working stroke.