Hand-held battery-powered grease gun

A hand-held battery-powered dispenser for lubricant or other pumpable material such as lubricating grease, comprising:

• a barrel holding a supply of said material;
• a head at one end of the barrel extending laterally from the barrel having a bore therein constituting a pump cylinder extending laterally with respect to the barrel;
• a plunger slidable in the bore;
• the head having an inlet intersecting the bore in communication with the barrel for the flow of said material from the barrel to the bore and an outlet for the bore spaced from the inlet toward one end of the bore;
• the plunger being slidable in the bore across the inlet toward said one end of the bore through a pumping stroke for pumping said material under pressure out through the outlet, and away from said one end of the bore through a return stroke for priming the bore;
• means forming a handle, the handle being tubular and extending from the head alongside the barrel, the axis of the handle being generally parallel to that of the barrel, the handle being so sized and spaced from the barrel as to enable a user to grasp and hold the dispenser in one hand by the handle with the hand of the user substantially surrounding the handle and with the fingers of the user extending into the space between the handle and the barrel;
• an electric motor in the handle at the end thereof toward the head, said motor having an output shaft, the axis of the shaft extending generally parallel to the axis of the handle;
• a battery means received within the handle at the end thereof away from the head for energizing the motor, a circuit interconnecting the battery means and the motor including a switch operable by a user holding the dispenser in his hand by the handle for starting and stopping the motor;
• drive means in the head operable by the motor for reciprocating the plunger comprising gear means rotatably mounted in the head and means interconnected with the gear means and the plunger for reciprocating the plunger longitudinally within the bore;
• and a flywheel on said shaft for storing energy developed during each return stroke and releasing the stored energy to assist in moving the plunger during each pressure stroke, said shaft extending from the motor into the head and interconnected with the drive means;
• the handle being part of a housing formed to enclose the head and to contain the battery means and the motor, said housing being a two-part housing split in a plane extending generally longitudinally and centrally of the handle and the barrel, with means for removably securing the parts of the housing together, said parts being formed to provide an enclosure for the head with an opening in said enclosure for the barrel, the barrel extending through said opening;
• the two parts of the housing being formed to provide a yoke for the barrel at the end of the handle opposite the enclosure for the head.