Abstract: A portable grease gun with a dual pressure output capability which can be selectively changed by the user with little effort. The larger diameter plunger is slidable within a plunger retainer. The larger diameter plunger has a bore through them in which a smaller diameter plunger is slidable. The smaller diameter plunger moves when an actuating lever is operated to compress grease in the grease gun. The larger diameter plunger may be adjusted to remain static during operation of the actuating lever or it may be adjusted to move during all or part of the compression stroke of the actuating lever. A high pressure can be generated by movement of the smaller diameter plunger alone, or a high flow volume can be generated by movement of the smaller and larger diameter plungers in unison.

Abstract: A battery powered grease gun has an overpressure relief valve for returning grease to the grease barrel mounted to the grease gun head when a plugged zerk prevents grease from exiting the output port. The grease gun head includes a small relief passageway joined to the output port of the grease gun head which is closed by an adjustable check valve. When the pressure of grease in the output port rises above a preselected pressure, grease will pass through the relief passageway to the grease barrel or, if so equipped, to the grease supply adapter which is mounted to the grease gun head. The grease gun head is additionally provided with a sampling duct which is joined to the output port. The sampling duct couples the output port to another port in which a pressure gauge or a pressure transducer may be installed. The pressure of grease in the output port may be displayed on the pressure gauge or on a display coupled to the transducer.

Abstract: A portable grease gun with a dual pressure output capability which can be selectively changed by the user with little effort. A larger diameter plunger is longitudinally coupled to an extension. The larger diameter plunger and its extension are variable in length by manual rotation of the extension relative to the larger diameter plunger. The larger diameter plunger is slidable within a plunger retainer over a limited range and is not free to rotate within the plunger retainer. The larger diameter plunger and the plunger extension have aligned bores through them in which a smaller diameter plunger is slidable. The smaller diameter plunger moves when an actuating lever is operated to compress grease in the grease gun. The larger diameter plunger may be adjusted to remain static during operation of the actuating lever or it may be adjusted to move during all or part of the compression stroke of the actuating lever.