Floor Grinding Machine and Method of Operating Floor Grinding Machine

Abstract

This document provides a method of operating a floor grinding machine 100. The method comprises providing a grinding machine 100 comprising a frame 101, a motor 102 and at least one grinding element 1, causing the motor to drive the grinding element so as to rotate at a rotational speed, while in contact with a floor surface to grind, polish or mill the floor surface, determining an actual value of a motor operating parameter, determining a nominal value of the motor operating parameter, comparing the actual value of the motor operating parameter with the nominal value of the motor operating parameter, if a difference between the actual value of the motor operating parameter and the nominal value of the motor operating parameter exceeds a predetermined difference threshold, determining at least one grinding parameter to be adjusted, and causing the at least one grinding parameter to be adjusted.

What is claimed is: 
     
         1 . A floor grinding machine for grinding or polishing floor surfaces comprising:
 a machine frame;   a motor, supported by the machine frame;   a grinding head, supported by the machine frame and operably coupled to the motor, the grinding head being rotatably drivable by the motor;   a user interface configured to provide information to the user and to receive user inputs; and   a control circuit operably coupled to the user interface and configured to control the motor based on a received sensor signal, the control circuit being further configured to:   compare an actual value of a motor operating parameter with a nominal value of the motor operating parameter for a rotational speed of the grinding head, and   responsive to a difference between the actual value of the motor operating parameter and the nominal value of the motor operating parameter exceeding a predetermined difference threshold, providing an instruction on the user interface for the user to adjust a grinding parameter on the grinding head.   
     
     
         2 . The floor grinding machine of  claim 1 , wherein the user interface comprises a display, and
 wherein the instruction is visually presented to the user on the display.   
     
     
         3 . The floor grinding machine of  claim 1 , wherein the user interface comprises a touch screen display,
 wherein the instruction is visually presented to the user on the touch screen display, and   wherein the user provides an input to control the floor grinding machine via the touch screen display responsive to the instruction.   
     
     
         4 . The floor grinding machine of  claim 1 , wherein the actual value of the motor operating parameter is current, torque or power determined by:
 measuring a measured value of the motor operating parameter and deriving the actual value of the motor operating parameter based on the measured value,   determining a rotational speed of the motor,   determining a motor efficiency of the motor at the rotational speed, and   determining the actual value of the motor operating parameter as the measured value adjusted by the motor efficiency.   
     
     
         5 . The floor grinding machine of  claim 4 , wherein, responsive to the difference between the actual value of the motor operating parameter and the nominal value of the motor operating parameter exceeding the predetermined difference threshold, determining a grinding parameter to be adjusted, and providing the instruction for the grinding parameter to be adjusted. 
     
     
         6 . The floor grinding machine of  claim 5 , wherein the control circuit further provides a second instruction for adjusting a second grinding parameter in response to a determination that the second grinding parameter is to be adjusted. 
     
     
         7 . The floor grinding machine of  claim 6 , wherein the second instruction for adjusting the second grinding parameter is provided automatically by the control circuit to adjust the second grinding parameter. 
     
     
         8 . The floor grinding machine of  claim 7 , wherein the control circuit informs the user of the adjustment of the second grinding parameter via the user interface, and
 wherein the control circuit is further configured for receiving a user input acknowledging that the second grinding parameter has been adjusted.   
     
     
         9 . The floor grinding machine of  claim 1 , wherein determining the nominal value of the motor operating parameter comprises determining the nominal value of the motor operating parameter at the rotational speed by calculation or a lookup table based on the rotational speed. 
     
     
         10 . The floor grinding machine of  claim 9 , wherein the lookup table provides a motor efficiency at the rotational speed and the nominal value of the motor operating parameter is adjusted by the motor efficiency. 
     
     
         11 . The floor grinding machine of  claim 1 , wherein the predetermined difference threshold is set to less than 30% of an amount of a difference between a nominal value of power and an actual value of power. 
     
     
         12 . The floor grinding machine of  claim 11 , wherein the control circuit is further configured to adjust the predetermined difference threshold based on a tool type. 
     
     
         13 . The floor grinding machine of  claim 1 , wherein adjusting the grinding parameter comprises:
 determining a torque produced by the motor,   comparing the torque produced with a desired torque range, and   if the torque produced is outside the desired torque range, instructing the user to adjust the grinding pressure via the user interface.   
     
     
         14 . The floor grinding machine of  claim 13 , wherein, responsive to the torque produced being below the desired torque range and the grinding process being a dry grinding process, the control circuit further being configured for:
 increasing a grinding pressure,   activating or increasing an aerosol supply, and   reducing a flow to a dust collector, operatively connected to the grinding machine.   
     
     
         15 . The floor grinding machine of  claim 13 , wherein, responsive to the torque produced being below the desired torque range and the grinding process being a wet grinding process, the control circuit further being configured for:
 increasing a grinding pressure, and   increasing a water feed rate.   
     
     
         16 . The floor grinding machine of  claim 13 , wherein, responsive to a predetermined period elapsing after the instructing the grinding parameter to be adjusted, and a re-determined torque remaining below a predetermined low torque threshold, the control circuit further being configured for:
 adjusting a grinding head rotation speed,   changing a grinding head rotation direction,   adjusting a grinding disc rotation speed, and   changing a grinding disc rotation direction.   
     
     
         17 . The floor grinding machine of  claim 13 , wherein, responsive to the torque produced being above the desired torque range and the grinding process being a dry grinding process, the control circuit further being configured for:
 decreasing a grinding pressure, and   deactivating or decreasing an aerosol supply.   
     
     
         18 . The floor grinding machine of  claim 13 , wherein, responsive to the torque produced being above the desired torque range and the grinding process being a wet grinding process, the control circuit further being configured for:
 decreasing a grinding pressure, and   reducing a water feed rate.   
     
     
         19 . The floor grinding machine of  claim 13 , wherein, responsive to a predetermined period elapsing, a re-measured torque is determined to be below a low torque threshold, or above a high torque threshold, the control circuit further being configured for prompting the user of the floor grinding machine to:
 change tool, or   change grinding process between dry and wet grinding processes.   
     
     
         20 . A floor grinding machine for grinding or polishing floor surfaces comprising:
 a machine frame;   a motor, supported by the machine frame;   a grinding head, supported by the machine frame and operably coupled to the motor, the grinding head being rotatably drivable by the motor;   a user interface configured to receive user inputs; and   a control circuit operably coupled to the user interface and configured to control the motor based on a received sensor signal, the control circuit being further configured to:   compare an actual value of a motor operating parameter with a nominal value of the motor operating parameter for a rotational speed of the grinding head, and   responsive to a difference between the actual value of the motor operating parameter and the nominal value of the motor operating parameter exceeding a predetermined difference threshold, causing a grinding parameter on the grinding head to be adjusted.