Portable pneumatic percussion tool - has conical spring fitted between valve plate and inlet tube to absorb shocks

摘要

A portable pneumatic percussion tool, which may be used as a riveter or for fettling castings, has a piston (8) sliding in a cylinder (12). Once the inlet valve (18) is opened by the trigger (15) the piston (8) is raised and then forced downwards by compressed air to strike the head of the tool. At the end of its upward stroke the piston impacts the valve plate (10) which seals the upper end of the cylinder (12). The shock of this impact is absorbed by fitting a conical spring (55) between the valve plate (10) and the undersurface (31) of the air inlet tube (26).