Electrically powered automatic lubricant dispenser

An automatic lubricant dispenser comprising:

• a housing adapted to hold a supply of a fluent lubricant and having one side formed with an outlet adapted to be connected to a machine to be lubricated and an opposite side;
• a piston in the vessel movable forward toward the one side to force the lubricant from the outlet;
• drive means including
• an electrical motor having a rotary output shaft, and
• a force-transmitting coupling between the shaft and the piston, the motor being electrically energizable able to advance the piston forward;
• an electric power source;
• and
• means including an electrical circuit between the source and the motor and including a pair of electrically conductive and mutually engageable contact elements for periodically energizing the motor from the source and thereby advancing the piston an increment and pumping a dose of the lubricant from the outlet, one of the elements being fixed to and rotatable with the shaft and the other fixed to the housing, one of the elements being an arcuate contact strip centered on an axis of the shaft and formed with a gap and the other element being a wiper engaging the strip and falling in the gap out of electrical contact with the strip in a predetermined angular position of the shaft in the housing.