Handheld Brush Positioner with Retraction Stop Sensing

Abstract

A tube cleaning apparatus has a handheld brush positioner and a control system for controlling operation of a drive unit, wherein the control system is operable to provide current to a drive motor to cause the drive motor to operate the drive unit to extend or retract a flexible shaft, sleeve and brush; and to receive a stop signal from a stop sensor to terminate retraction thereof.

What is claimed is: 
     
         1 . A tube cleaning apparatus comprising:
 a brush positioner having a guide tube and a forward end;   an elongated flexible shaft;   a flexible sleeve enclosing the flexible shaft;   a brush assembly, for cleaning the interior surfaces of tubes, affixed to a distal end of the elongated flexible shaft;   a reversible drive motor;   a drive unit powered by the drive motor for engaging the sleeve and flexible shaft and extending and retracting the sleeve and flexible shaft, and the brush assembly affixed to the flexible shaft, into an interior surface of a tube to be cleaned;   a mechanical stop sensor provided in the brush positioner to sense that the brush assembly is retracted to a position where it is located in the forward end of the brush positioner with at least some of the brush assembly extending out from the forward end of the brush positioner;   a control system for controlling operation of the drive unit, the control system including a continuously operating pump providing a supply of control air operably connected to a forward control valve and a reverse control valve;   whereby closing the forward control valve causes an increase in air pressure in a forward air switch and activation of a forward electrical switch to provide current to the drive motor to cause the drive motor to operate the drive unit to extend the sleeve, flexible shaft and brush;   whereby closing the reverse control valve causes an increase in air pressure in a reverse air switch and activation of a reverse electrical switch to provide current to the drive motor to cause the drive motor to operate the drive unit to retract the sleeve, flexible shaft and brush;   whereby if the stop sensor senses that the brush assembly is retracted to a position where it is located in the forward end of the brush positioner with at least some of the brush assembly extending out from the forward end of the brush positioner, a vent valve operably connected to the reverse air switch is opened, causing a decrease in air pressure in the reverse air switch and deactivation of the electrical switch providing current to the drive motor and thereby terminate operation of the drive motor and drive unit and stopping retraction of the sleeve, flexible shaft and brush.   
     
     
         2 . The tube cleaning apparatus of  claim 1 , wherein the stop sensor comprises a mechanical linkage which includes a roller contacting the sleeve, flexible shaft, and brush assembly, the linkage pivoting to keep the vent valve closed when a larger diameter component is contacting the roller, the linkage pivoting to bear against and open the vent valve when a smaller diameter component is contacting the roller. 
     
     
         3 . The tube cleaning apparatus of  claim 2 , wherein the linkage pivots to keep the vent valve closed when the flexible shaft and flexible sleeve are contacting the roller. 
     
     
         4 . The tube cleaning apparatus of  claim 3 , wherein the linkage pivots to bear against and open the vent valve when the flexible shaft or the brush assembly are contacting the roller. 
     
     
         5 . The tube cleaning apparatus of  claim 1 , wherein the brush assembly includes a plastic bristle brush, and a connector between the flexible shaft and the bristle brush. 
     
     
         6 . The tube cleaning apparatus of  claim 1 , wherein the vent valve is operably connected to an exhaust port, and manually blocking the exhaust port permits operation of the reverse control valve. 
     
     
         7 . The tube cleaning apparatus of  claim 1 , wherein the brush positioner comprises a handheld unit, and the forward control valve and reverse control valve are actuated by a foot-operated pedal switch. 
     
     
         8 . The tube cleaning apparatus of  claim 1 , wherein the brush positioner comprises a feed gun with a pistol grip, and the forward control valve and reverse control valve are actuated by a finger-operated rocker trigger provided in the pistol grip. 
     
     
         9 . The tube cleaning apparatus of  claim 1 , wherein the brush positioner is a hollow body and contains a drain hose. 
     
     
         10 . A brush positioner for a tube cleaning apparatus, comprising:
 a handheld body having a forward end and a guide tube extending therethrough;   a forward control valve;   a reverse control valve;   a vent valve operably connected to the reverse control valve to vent a line associated with the reverse control valve;   a stop sensor provided in the brush positioner to sense that a brush assembly is retracted to a position where it is located in the forward end of the brush positioner with at least some of the brush assembly extending out from the forward end of the brush positioner and to cause the vent valve to open.   
     
     
         11 . The brush positioner of  claim 10 , wherein the stop sensor comprises a mechanical linkage which includes a frame, and a lower roller, the frame being pivotably mounted to the brush positioner, the frame being pivotable to keep the vent valve and being pivotable to bear against and open the vent valve. 
     
     
         12 . A tube cleaning apparatus comprising:
 a brush positioner having a guide tube and a forward end;   an elongated flexible shaft;   a flexible sleeve enclosing the flexible shaft;   a plastic bristle brush for cleaning the interior surfaces of tubes, and a connector, the connector being mounted to an end of the elongated flexible shaft;   a reversible drive motor;   a drive unit powered by the drive motor for engaging the sleeve and flexible shaft and extending and retracting the sleeve and flexible shaft, and the brush assembly affixed to the flexible shaft, into an interior surface of a tube to be cleaned;   a stop sensor provided in the brush positioner to sense that the flexible shaft or connector are retracted to a position where it is located in the forward end of the brush positioner with at least some of the brush assembly extending out from the forward end of the brush positioner;   a control system for controlling operation of the drive unit, wherein the control system is operable to: activate a forward electrical switch to provide current to the drive motor to cause the drive motor to operate the drive unit to extend the sleeve, flexible shaft and brush; and activate a reverse electrical switch to provide current to the drive motor to cause the drive motor to operate the drive unit to retract the sleeve, flexible shaft and brush; and receive a stop signal from the stop sensor to terminate activation of the reverse electrical switch and thereby terminate operation of the drive motor and drive unit and stopping retraction of the sleeve, flexible shaft and brush.   
     
     
         13 . The tube cleaning apparatus of  claim 12 , wherein the control system includes a continuously operating pump providing a supply of control air operably connected to a forward control valve and a reverse control valve;
 whereby closing the forward control valve causes an increase in air pressure in a forward air switch and activation of the forward electrical switch to provide current to the drive motor to cause the drive motor to operate the drive unit to extend the sleeve, flexible shaft and brush;   whereby closing the reverse control valve causes an increase in air pressure in a reverse air switch and activation of the reverse electrical switch to provide current to the drive motor to cause the drive motor to operate the drive unit to retract the sleeve, flexible shaft and brush;   whereby if the stop sensor senses that the flexible shaft or connector are retracted to a position where the bristle brush is located in the forward end of the brush positioner with at least some of the bristle brush extending out from the forward end of the brush positioner, a vent valve operably connected to the reverse air switch is opened, causing a decrease in air pressure in the reverse air switch and deactivation of the electrical switch providing current to the drive motor and thereby terminate operation of the drive motor and drive unit and stopping retraction of the sleeve, flexible shaft and brush.   
     
     
         14 . The tube cleaning apparatus of  claim 13 , wherein the stop sensor comprises a mechanical linkage which includes frame holding a lower roller contacting the sleeve, flexible shaft, and brush assembly, the linkage pivoting to keep the vent valve closed when the flexible sleeve and flexible shaft are contacting the roller, the linkage pivoting to bear against and open the vent valve when the flexible shaft or connector are contacting the roller. 
     
     
         15 . The tube cleaning apparatus of  claim 14 , wherein the vent valve is operably connected to an exhaust port, and manually blocking the exhaust port permits operation of the closing the reverse control valve. 
     
     
         16 . The tube cleaning apparatus of  claim 12 , wherein the control system includes a low voltage microcontroller providing a forward control activation signal to a forward electrical relay to cause the drive motor to operate the drive unit to extend the sleeve, flexible shaft and brush, and a reverse control activation signal to a reverse electrical relay to cause the drive motor to operate the drive unit to retract the sleeve, flexible shaft and brush; and the microcontroller being connected to the stop sensor whereby if the stop sensor is activated, the microcontroller terminates its signal to the reverse electrical relay and thereby terminates operation of the drive motor and drive unit, stopping retraction of the sleeve, flexible shaft and brush. 
     
     
         17 . The tube cleaning apparatus of  claim 16 , wherein the stop sensor comprises a magnetic or mass or proximity sensor, and a mechanical linkage which includes a frame holding a lower roller contacting the sleeve, flexible shaft, and brush assembly, the linkage pivoting to keep an upper end of the frame separated from the stop sensor when the flexible sleeve and flexible shaft are contacting the roller, the linkage pivoting to locate the upper end of the frame adjacent the stop sensor to activate the stop senor when the flexible shaft or connector are contacting the roller. 
     
     
         18 . The tube cleaning apparatus of  claim 16 , wherein the brush positioner comprises a handheld unit, and the forward control valve and reverse control valve are actuated by a foot-operated pedal switch. 
     
     
         19 . The tube cleaning apparatus of  claim 16 , wherein the brush positioner comprises feed gun with a pistol grip, and the forward control valve and reverse control valve are actuated by a finger-operated rocker trigger provided in the pistol grip. 
     
     
         20 . The tube cleaning apparatus of  claim 16 , wherein the microcontroller has a stop sensor override whereby pushing on both a forward control push button switch and a reverse control push button switch at the same time permits retraction of the flexible shaft past a stop position into a protective casing.