Patent ID: 9022177
Filing Date: 2015-05-05
Classification: F16N,Y10T

Abstract:
1. Apparatus for supplying lubricant, comprising: a reservoir for holding lubricant, said reservoir having a reservoir outlet; a pump comprising a cylinder defining a cylinder bore, a cylinder inlet in communication with said reservoir outlet for flow of lubricant from the reservoir into the cylinder bore, and a cylinder outlet supplying lubricant, a piston movable in the cylinder bore; a drive mechanism including a stepper motor for moving the piston in the cylinder bore, said stepper motor having a continuous duty operating range and having a stall range; a controller for controlling the operation of the stepper motor by selectively applying pulse width modulated (PWM) pulses to the stepper motor to control a speed and/or a torque of the stepper motor to move the piston to dispense lubricant; a sensor for sensing a condition of the apparatus and providing a condition signal indicative of the condition; said controller responsive to the condition signal to selectively apply the PWM pulses to the stepper motor to vary the speed and/or the torque of the stepper motor as a function of the condition signal by applying PWM pulses having a power within the continuous duty operating range of the stepper motor; and said controller responsive to the condition signal to selectively apply the PWM pulses to the stepper motor to vary the speed and/or the torque of the stepper motor as a function of the condition signal by applying overdrive PWM pulses for a period of time, said overdrive PWM pulses having an overdrive power greater than the continuous duty operating range of the stepper motor and said overdrive PWM pulses having an overdrive power less than the stall range of the stepper motor.