Control circuit for grinding machine

Abstract

A circuit for a grinding machine has inputs for a sensor and a WHEEL START switch and an output to a grind wheel. The circuit initiates the wheel upon receiving a particular sensor signal after the WHEEL START switch is actuated. A grinding machine includes the circuit as well as working components including a grind wheel, a feed arm and a feed arm sensor. The circuit is responsive to the feed arm sensor, such that the control circuit does not initiate the grind wheel unless the feed arm is retracted. The grinding machine may be a centerless grinding machine and the circuit may control the regulating wheel and the grind wheel. A grinding machine can be operated by actuating a WHEEL START switch and receiving a sensor signal that indicates a condition on the grinding machine. The signal is compared to a predetermined value, and if the signal is correct, the grind wheel is initiated.

1 . A logic circuit for a grinding machine, the logic circuit comprising:
 inputs for a signal from a WHEEL START switch and for a sensor signal from each of 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; 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 initiating operation of the grind wheel motor after receiving a predetermined sensor signal from at least one of said one or more sensors.   
     
     
         2 . The circuit of  claim 1 , wherein the logic circuit is configured to generate a FAULT ALERT signal when the predetermined sensor signal is not received from each of said one or more sensors. 
     
     
         3 . The circuit of  claim 1 , wherein the logic circuit is configured to cease operation of the grind wheel motor upon receiving a sensor signal that indicates a stop condition. 
     
     
         4 . 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.   
     
     
         5 . The control circuit of  claim 4 , wherein the logic circuit is configured to generate a fault alert signal when a precondition to operating the grinding machine is not met. 
     
     
         6 . The control circuit of  claim 4 , comprising a feed arm sensor, wherein the precondition is that the feed arm is in the retracted position. 
     
     
         7 . The control circuit of  claim 4 , wherein the logic circuit is configured to cease operation of the grind wheel motor upon receiving a signal that indicates a stop condition. 
     
     
         8 . 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.   
     
     
         9 . 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.   
     
     
         10 . The grinding machine of  claim 9 , further comprising one or more working components including a hydraulic system including a hydraulic pump, and a coolant pump for pumping coolant through the grind wheel, the grinding machine further comprising one or more sensors including a hydraulic pressure sensor, a wheel guard position sensor, a coolant pressure sensor, and a feed arm sensor, and wherein the control circuit is responsive to the one or more sensors. 
     
     
         11 . 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.   
     
     
         12 . The method of  claim 11  wherein the grinding machine comprises a feed arm that is movable between an advance position and a retracted position, and wherein the first sensor is a feed arm sensor that indicates the position of the feed arm, and wherein the precondition is that the feed arm is in a retracted position. 
     
     
         13 . The method of  claim 11  wherein the grinding machine comprises one or more sensors that indicate conditions of the grinding machine, the method comprising monitoring the one or more sensors after initiating the grind wheel motor and stopping the grind wheel motor if a sensor indicates that a stop condition has occurred on the grinding machine. 
     
     
         14 . The method of  claim 11 , further comprising ceasing operation of the grinding machine upon receipt of a sensor signal that indicates that a stop condition has occurred on the grinding machine.