Motor control device

A motor control device for controlling a motor comprising:

• motor driving means for supplying power to said motor and driving said motor in a first direction in response to a motor drive signal;
• load detecting means for detecting a load of said motor and for developing a load signal in response thereto;
• overload detecting means, responsive to said load signal, for determining whether said motor is in an overload condition by comparing the load signal to a predetermined reference load value indicative of an overload condition, said overload detecting means developing an overload signal when said overload condition is detected and developing a normal condition signal when said overload condition is absent;
• and
• controlling means, responsive to the overload condition signal of said overload detecting means, for inhibiting said motor drive signal for a predetermined time period, and for supplying a control signal to said motor driving means during said predetermined time period for alternately driving said motor between said first direction and in a second direction opposite to said first direction;
• said overload detecting means again determining after said predetermined time period has elapsed whether said motor is in said overload condition and developing said overload condition signal to again initiate inhibition of the motor drive signal from said motor driving means for said predetermined time period if an overload condition continues to exist;
• said motor driving means being responsive to said normal condition signal and resupplying said motor drive signal to said motor driving means upon the elapse of said predetermined time period when said overload condition is absent;
• said overload detecting means, said controlling means, and said motor driving means collectively operating to intermittently and reversibly drive said motor driving means during said overload condition.