Patent ID: 8517223
Filing Date: 2013-08-27
Classification: F16N

Abstract:
1. A two stage grease gun, comprising: a handle capable of being actuated by a user; a volume piston chamber; a high pressure piston chamber that does not share a common longitudinal axis with the volume piston chamber, wherein the volume piston chamber has a greater volume than the high pressure piston chamber; a high volume/low pressure piston moved by the handle during actuation of the handle by the user, wherein the high volume/low pressure piston is arranged to deliver grease at a high volume and low pressure, wherein the high volume/low pressure piston is disposed in the volume piston chamber; a high pressure/low volume piston moved by the handle during actuation of the handle by the user, wherein the high pressure/low volume piston is arranged to deliver grease at a high pressure and low volume, wherein the high pressure/low volume piston is disposed in the high pressure piston chamber, and wherein the high volume/low pressure piston is free from engagement with the high pressure/low volume piston; and a by-pass check valve configured to actuate based upon a backpressure such that user actuation of the by-pass check valve is not needed, wherein the by-pass check valve effects the amount of grease dispensed by way of the high volume/low pressure piston such that when the backpressure is sufficiently high the by-pass check valve actuates to prevent grease from being dispensed by way of the high volume/low pressure piston and allows grease to be dispensed by way of the high pressure/low volume piston.