Control ports in door closers - are produced by spark erosion or laser machining

摘要

Door closers have a powerful damping mechanism consisting of a piston moving in a cylinder against the pressure of oil escaping through a control port. The ports open into the cylinder chamber and are in the path of the piston. Conventional methods of drilling the holes for the ports leave burrs and sharp edges that are damaging to seals and O-rings. The passages (30,31) through which the oil is throttled are produced by an erosive method such as spark erosion, laser machining, electtrochemical machining etc. USE/ADVANTAGE - Low-cost method of producing small burr free holes.