Spray gun with cartridge housed piston - has piston moving push rod, between which and piston crown is intermediate member with dia. increasing under pressure

摘要

The spray gun forces a substance from a cartridge, using a piston housed in the same. The cylindrical piston wall abuts the inner wall of the cartridge, the piston being movable by a pushrod attached to the bottom of the piston and forming part of the cartridge holder. An intermediate element (5), which under pressure increases its diameter, is fitted between the pushrod (4) and the piston bottom. The edge of the element is in contact with and acts on the wall (3a) of the piston. The element is preferably an elastically deformable disc (7), sandwiched between two rigid plates (6).