Pneumatic damper - with overload safety device used in pressure casting appts

摘要

Danger of the piston of a damper being pushed through the bottom of its cylinder owing to escape of the damping medium is avoided by having a conically shaped spigot in the centre of the underside of the piston, the spigot working in a slightly larger orifice in the cylinder end wall. As the piston approaches its bottom point, the wider part of the spigot comes within the orifice, thereby restricting flow of hydraulic medium to the underside of the piston, creating a partial vacuum which rapidly halts further movement.