Percussion fettling of castings in foundry - where casting is held by jig while compressed air hammer is used to knock runner or riser off casting

摘要

Casting is placed on the narrow top surface of a peg, so that a runner, riser, feeder, or other unwanted part of the casting is not supported. A hammer is then employed to apply a violent shock in a vertical direction on the unsupported runner etc. so it breaks off the casting. The pref. fettling appts. includes a vertical peg with a chamfered top forming a very small rectangular support surface on which the casting is placed. The hammer is driven vertically by a pneumatic cylinder fixed on one end of a swivel arm located on a vertical pillar and actuated by a hydraulic cylinder so the hammer can be located just above the runner or other part to be broken off the casting.