Control circuit for grinding machine

A control circuit for operating a grinding machine, comprising:

• a power-on switch;
• one or more sensors selected from the group consisting of a feed arm sensor, a hydraulic pressure sensor, a wheel guard sensor, and a coolant sensor, each said sensor providing a sensor signal that indicates a condition of the grinding machine;
• a WHEEL START switch;
• and
• a logic circuit configured to receive a signal from the WHEEL START switch and a sensor signal from said one or more sensors;
• and
• an output for connection to a grind wheel motor;
• wherein the logic circuit is configured to respond to actuation of the WHEEL START switch by initiating a WHEEL START logic operation that comprises initiation operation of the grind wheel motor after receiving a predetermined sensor signal from at least one of said one or more sensors.

A grinding machine, comprising:

• a control circuit;
• a grind wheel and a grind wheel motor that is responsive to the control circuit for operating the grind wheel;
• a movable feed arm for engaging a workpiece, the feed arm being movable between an advanced position for engaging a workpiece with the grind wheel and a retracted position for disengaging a workpiece from the grind wheel;
• and
• a feed arm sensor for the feed arm, capable of generating a signal to indicate whether the feed arm is in the retracted position;
• wherein the control circuit is responsive to the feed arm sensor, such that when the grinding machine is started, the control circuit does not initiate operation of the grind wheel motor or the regulating wheel motor unless the feed arm sensor indicates that the feed arm is in the retracted position.

A centerless grinding machine comprising:

• a control circuit;
• working components including a grind wheel and a grind wheel motor that is responsive to the control circuit for operating the grind wheel, a movable feed arm, a regulating wheel on the feed arm, a regulating wheel motor that is responsive to the control circuit, for operating the regulating wheel;
• wherein the feed arm is movable between an advanced position, in which the regulating wheel can engage a workpiece and cause such workpiece to engage the grind wheel, and a retracted position in which the regulating wheel permits said workpiece to disengage from the grind wheel;
• a feed arm sensor for the feed arm, capable of generating a signal to indicate whether the feed arm is in the retracted position;
• wherein the control circuit is responsive to the feed arm sensor, such that when the grinding machine is started, the control circuit does not initiate operation of the grind wheel motor or the regulating wheel motor unless the feed arm sensor indicates that the feed arm is in the retracted position.

A method of operating a grinding machine, comprising:

• receiving an actuation signal from a WHEEL START switch;
• receiving a first signal from a first sensor that indicates a condition on the grinding machine;
• comparing the first signal to a predetermined value;
• and
• initiating the grind wheel motor if the first signal satisfies the predetermined value.