Belt grinding machine tool with device for controlling the position of the abrasive belt

Abstract

A belt grinding machine tool with an operating head comprising an endless abrasive belt wound and stretched between at least two spaced rollers arranged parallel one another, of which a first is a driving roller and a second is a tensioning roller being supported to be adjustable in a direction which is substantially perpendicular to its axis of rotation. A device is provided for controlling the position of the abrasive belt which consists of at least a position sensor for sensing the position of the abrasive belt and at least an actuator for adjusting the position of the tensioning roller, in dependence of the position of the abrasive belt being sensed by the position sensor. The position sensor is a fork shaped optical sensor, or an optical sensor having an operatively equivalent shape, and the actuator is an electric drive.

1 . A belt grinding machine tool with an operating head comprising an endless abrasive belt wound and stretched between at least two spaced rollers arranged parallel one another, of which a first is a driving roller and a second is a tensioning roller, said tensioning roller being supported to be adjustable in a direction which is substantially perpendicular to its axis of rotation, a device for controlling the position of said abrasive belt consisting of at least a position sensor for sensing the position of the abrasive belt and at least an actuator for adjusting the position of the tensioning roller, in dependence of the position of the abrasive belt being sensed by said position sensor, wherein the position sensor is a fork shaped optical sensor, or an optical sensor having an operatively equivalent shape, and said actuator is an electric drive. 
     
     
         2 . A belt grinding machine tool according to  claim 1 , wherein said electric drive comprises a drive shaft and an angular position transducer for determining amount of rotation of said drive shaft. 
     
     
         3 . A belt grinding machine tool according to  claim 2 , wherein a gear reducing unit is operatively connected to said drive shaft of the electric drive. 
     
     
         4 . A belt grinding machine tool according to  claim 1 , wherein said position sensor and said electric drive are operatively connected together through a closed loop control circuit which determines the amount of shifting movement to be imparted to the said tensioning roller as a function of the position of the abrasive belt sensed by said position sensor. 
     
     
         5 . A belt grinding machine tool according to  claim 4 , wherein the position of said abrasive belt is controlled by said closed loop control circuit in continuous manner, in dependence of the position of said abrasive belt sensed by said position sensor. 
     
     
         6 . A belt grinding machine tool according to  claim 1 , wherein said operating head is intended for operation either with or without water, oil or water/oil emulsion coolant.