Automatic lubricant dispenser

An automatic lubricant dispenser comprising:

• a lower housing part formed with an outlet;
• a piston displaceable along an axis in the lower part, forming therein a compartment, and having a collar;
• a spindle extending along the axis in the collar, threaded into the piston, and having an upper end above the piston provided at the axis with a nut bearing axially on the collar;
• a body of fluent lubricant filling the compartment and forming with the spindle, piston, and lower housing part a lower subassembly;
• an upper housing part securable to the lower part via a screwthread and forming an upper subassembly;
• an insert mainly in the upper housing part and forming a battery compartment;
• a motor unit fixed to the insert and having an output shaft projecting downward therefrom at the axis and provided at the axis with a socket complementary to and axially engageable with the nut, the nut and socket releasably axially interfitting in each other to rotationally couple the motor output shaft to the spindle when the upper housing part holding the insert is mounted on the lower housing part;
• a slide bearing between the socket and the insert;
• a battery in the battery compartment;
• a circuit board fixed to the insert and connected between the battery and the motor unit;
• and
• an on-off switch mounted on the circuit board and actuatable to energize the motor unit from the battery, the insert, motor unit, battery, circuit board, and switch together forming a core subassembly normally held between the upper and lower subassemblies.