Single-piece piston with central bore for use in a

Abstract

A single-piece piston for use in a pneumatically-activated pump to meter a predetermined amount of lubricant or other liquid. The piston has a grooved end that includes a head portion and a circumferentially-disposed angled channel for containing a sealing member such as an O-ring. An adjacent stem section includes a longitudinally-disposed channel that is in fluid-flow connection with the angled channel. The piston is disposed within a chamber of the body of the pump. Lateral movement of the piston within the body causes the sealing member to shift and block and unblock the end of the longitudinal channel and an aperture in the angled channel, which allows liquid from a liquid chamber to flow into a central bore in the piston and to a pump chamber adjacent to the head of the piston's grooved end. The piston operates in association with an assembly for regulating the amount of liquid metered by the lubricator, a valve assembly for evacuating the liquid from the pump chamber into and through an outlet fitting, and a mechanism for regulating the flow of air into the outlet fitting to atomize the liquid.