Abstract: A coupler connected a hose of a grease gun includes a body having a path defined therethrough. A check valve unit and a sealing unit are located in the body. The check valve includes a spring which biases the sealing unit. A groove is defined in an outer surface of the body. A socket is mounted to the body and multiple pawls are received in the socket. The pawls each have a first end engaged with the groove, and a second end of each pawl is controlled to be connected to a fitting member. The socket has a flange extending from the inner periphery. The second ends of the pawls removably contact the flange. A trigger is pivotably connected to the body and drives the socket which is moved by pivoting the trigger so as to control the pawls to engaged with or release the fitting member.

Abstract: The auto/single functions selecting device of a grease gun includes a switch unit connected to the main body of the grease gun. When the user switches the switch unit to the first position, a single shot is available when pulling the trigger one time. When the user switches the switch unit to the second position, the grease is continuously supplied when keep pulling the trigger. The grease gun provides the function of single shot and the function of auto shot.

Abstract: An air grease gun includes a grip, a barrel, a spout pipe unit and a grease storage tube. A generally Y-shaped air passage is formed in the grip and is bifurcated into a first branch and a second branch at the lower end portion of the grip. A compressed air source is communicated with the first branch. The second branch is communicated with the lower air chamber of the grease storage tube via an air tube. A valve normally closes the upper section of the air passage, which is above the first and second branches. The compressed air flowing from the compressed air source enters the grease storage tube via the first and second branches and via the air tube so as to push a tube piston upward, thereby impelling the grease in the grease storage tube into the barrel. Upon actuation of a trigger, the valve opens the air passage so that the compressed air flows into the barrel through the upper section of the air passage, thereby pneumatically moving the grease in the barrel to the spout outlet of the gun.