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.

Claims

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.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 is a front, top, and left side perspective view of an embodiment of a forward end of a handheld brush positioner in accordance with the invention.

[0024] FIG. 2 is a left side elevation view of the forward end of the handheld brush positioner of FIG. 1.

[0025] FIG. 3 is a left side cutaway view of the forward end of the handheld brush positioner of FIG. 1 showing the stop mechanism with retraction enabled.

[0026] FIG. 4 is a left side cutaway view of the forward end of the handheld brush positioner of FIG. 1 showing the stop mechanism with retraction diabled.

[0027] FIG. 5 is a front elevation view of the forward end of the handheld brush positioner of FIG. 1.

[0028] FIG. 6 is a top plan view of the forward end of the handheld brush positioner of FIG. 1.

[0029] FIG. 7 is a rear, top, and left side perspective view of a complete handheld brush positioner in accordance with the invention.

[0030] FIG. 8 is a left side elevation view of the complete handheld brush positioner of FIG. 7.

[0031] FIG. 9 is a left side cutaway view of the complete handheld brush positioner of FIG. 1 showing a fully retracted brush.

[0032] FIG. 10 is the left side cutaway view of FIG. 9 showing an optional a foot-activated pedal switch.

[0033] FIG. 11 is a schematic illustration of the operation of a pneumatic control system of a tube cleaning machine including a handheld brush positioner with retraction stop sensing.

[0034] FIG. 12 is a left side cutaway view of a handheld brush positioner of a tube cleaning machine incorporating a microcontroller control system with retraction stop sensing.

DETAILED DESCRIPTION OF THE INVENTION

[0035] Referring now to FIG. 11, a schematic pneumatic control system 1000 of a tube cleaning machine including a handheld brush positioner with retraction stop sensing is shown. Pressurized air is delivered from a compressor 1002 to a forward control valve 1004 and a reverse control valve 1006. Valves 1004 and 1006 are normally open valves that vent to the atmosphere. The two valves 1004 and 1006 are preferably controlled by a rocker or other manual control that allows only one valve 1004, 1006 to be closed at a time. Closing forward control valve 1004 increases pressure in line 1008 and then in forward air switch 1010. When pressure reaches a certain level, air switch 1008 activates an electrical switch to provide current to drive motor 1012 to cause the drive motor to extend a flexible shaft and brush of a tube cleaning machine. Closing reverse control valve 1006 increases pressure in line 1014 and then in reverse air switch 1016. When pressure reaches a certain level, reverse air switch 1016 activates an electrical switch to provide current to drive motor 1012 to cause the drive motor 1012 to turn in the opposite direction and retract the flexible shaft and brush of a tube cleaning machine. When the flexible shaft and brush is retracted to a desired position in the handheld brush positioner, the retraction is detected by a stop sensor, which then causes vent valve 1018 in the brush positioner to open. The opening of vent valve 1018 releases pressure from line 1014 and reverse air switch 1016, stopping drive motor 1012, and preventing further retraction of the flexible shaft and brush. If it is desired to further withdraw the flexible shaft and brush, the stop signal from the stop sensor can be overridden by blocking the exit of air from valve 1018 at exhaust port 1020. Blocking exhaust port 1020 prevents venting of air pressure, so that closing reverse control valve 1006 will cause an increase in pressure in line 1014 and then in reverse air switch 1016, to activate the electrical switch to provide current to drive motor 1012 to cause the drive motor 1012 to further retract the flexible shaft and brush.

[0036] Referring to FIGS. 1-6, the forward end 10 of a handheld brush positioner 110 is shown. FIGS. 7-9 show the forward end 10 mounted on a rear end 100 with includes a pistol grip 82 to provide the complete brush positioner 110. Brush positioner 110 is a handheld unit desirably controlled by holding the pistol grip 82 and the lower part of the body 70 of forward end 10 as seen in FIGS. 7-8.

[0037] The forward end 10 of brush positioner 110 has at its forward end 12 a brush assembly 13. The brush assembly 13 includes a plastic bristle brush 20 mounted to a connector 22. The brush assembly 13 is mounted to a flexible shaft 24 which is contained in a plastic sleeve 26. The forward end 12 of the brush positioner includes a resilient conical bumper 14 that helps to prevent damage to tubes to be cleaned in the event the operator loses control of or grip on the brush positioner 110. A drain hose 16 is provided in the body of the brush positioner 110 to divert any water and cleaning liquids that may be flushed from the tubes of the equipment being cleaned and which flows backwardly into the body of brush positioner 110. Drain hose 16 may be provided with a nipple 17, and in use nipple 17 can be connected to a longer hose to send wastewater to an appropriate catch basin for wastewater processing. A guide tube 18 extends through the body of the brush positioner 110 which provides a passageway for the flexible shaft and brush assembly. Guide tube 18 may be connected via port 118 to a hose that is connected to the housing of the tube cleaning machine and through which the flexible shaft and brush assembly extend.

[0038] Referring to FIGS. 7-9, a finger-activated pneumatic trigger switch 80 for controlling the pneumatic control system 1000 of a tube cleaning machine of FIG. 11 is shown in the brush positioner 110. Trigger switch 80 is positioned vertically in the feed gun pistol grip 82, and the two ends of the switch provide the operator with control of extension and retraction of the casing, flexible shaft, and brush. The trigger switch 80 is fed two continuous streams of control air; one to a port located behind the upper end of the rocker switch trigger, and one to a port located behind the lower end of the rocker switch trigger. In its default neutral position, the control air is vented out through the two ports and no action is actuated. When the rocker switch trigger is squeezed on its upper end, the inner face of the upper end of the switch bears against and closes an upper vent opening 84, causing an increase in air pressure in the forward air line, which line connects to a forward air switch. The increase in air pressure is a pneumatic signal that is received by the forward air switch. The forward air switch activates the reversible drive motor, causing it to operate the drive rollers to extend the flexible shaft and brush assembly into a tube. When released, the trigger returns to a neutral position, stopping movement of the brush. The operator can then squeeze the rocker switch trigger at its lower end, so that the inner face of the lower end of the switch bears against and closes a lower vent opening 86, causing an increase in air pressure in the reverse air line, which line connects to a reverse air switch. The increase in air pressure is a pneumatic signal that is received by the reverse air switch. The reverse air switch activates the reversible drive motor, causing it to operate the drive rollers to retract the flexible shaft and brush assembly from the tube.

[0039] In an optional alternative embodiment, shown in FIG. 10, the trigger switch 80 is replaced with or can be supplemented with a foot-activated pedal switch 180. A foot-activated pedal switch 180 operates in the same way as described for the trigger switch 80 to operate the extension and retraction of a rotating flexible shaft and brush of a tube cleaning machine. The foot activated pedal switch includes a forward pedal, a neutral position, and a reverse pedal. Pressure from an operator's foot on the forward pedal closes a normally open port 184, increasing air pressure in the forward pedal line and activating a forward air switch, which activates the reversible drive motor, causing it to operate the drive rollers to extend the flexible shaft and brush assembly into a tube. When released, the pedal switch returns to the neutral position, stopping movement of the brush. Pressure from the operator's foot on the reverse pedal closes a normally open port 186, increasing air pressure in the reverse pedal line and activating a reverse air switch, which activates the reversible drive motor, causing it to operate the drive rollers to retract the flexible shaft and brush assembly into a tube.

[0040] In an alternative embodiment of a feed gun 210, shown in FIG. 12, the pneumatic control system 1000 of FIG. 11 is replaced with a low voltage microcontroller 2000, operating, for example, at 5 volts/20 mA. Triggering is controlled by two separate push button switches 280, 282. Instead of a closing a vent opening, the pushing of the forward control push button switch 280 causes the microcontroller to emit a forward control activation signal, which is amplified by a transistor to 12 V, and the amplified signal activates a forward electrical relay 2010 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. Pushing on the reverse control push button control switch 282 causes the microcontroller 2000 to emit a reverse control activation signal, which is amplified by a transistor to 12 V, and the amplified signal activates a reverse electrical relay 2020 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 until stopped by the stop sensor as described below.

[0041] Referring now to FIGS. 3 and 4, a cross-section of forward end 10 is shown. Flexible shaft 24 is contained in the guide tube 18. A forward guide tube 30 is positioned inside the forward end 10 near end 12 and is spaced part from guide tube 18, leaving a space therebetween for a retraction stop sensor as described hereafter.

[0042] Flexible shaft 24 with its plastic sleeve 26 is connected to connector 22 and brush 20 is mounted on connector 22. Flexible shaft 24 and plastic sleeve 26 have a greater diameter than the diameter of the flexible shaft 24 or connector 22. The difference in diameter is sufficient that it can be detected by a stop sensor. The stop sensor is a sensing means which may include a mechanical mechanism as described hereafter or an electronic sensor such as a proximity sensor.

[0043] In one embodiment, the stop sensor is a mechanical linkage 38. Referring now to FIGS. 3 and 9, mechanical linkage 38 includes an L-shaped pivot arm 50 includes a sufficient framework to retain a lower roller 52 at the lower end 53 of pivot arm 50. Roller 52 is positioned perpendicularly to the line of travel of the flexible shaft 24 and plastic sleeve 26. The plastic sleeve 26 rides on the roller 52, causing the upper end 54 of pivot arm 50 to be held away from the brush positioner vent valve 40, such that brush positioner vent valve 40 is closed. The L-shaped pivot arm pivots around pin 55, and has spring tension applied to it by spring 56, so that when lower roller 52 rides on the smaller diameter flexible shaft 24 or the connector 22, the upper end 54 of pivot arm 50 is pulled rearwardly.

[0044] A yoke 60 provides adjustment so that the mechanical linkage 38 will be operable as a stop sensor for a range of differently sized flexible shafts 24 and plastic sleeves 26. Yoke 60 accommodates a range of different diameters of flexible shafts 24 and plastic sleeves 26 by providing a threaded thumbscrew 62 mounted in a nut in the yoke 60, and by having an upper roller 58 placed above and opposite the lower roller 52 to maintain an appropriate spacing between the rollers 52, 58 so that that there is a slight tension thereon. By providing this, the lower roller 52 can appropriately ride on flexible shaft 24 and plastic sleeve 26, and the smaller diameter flexible shaft 24 or the connector 22, to enable the operation of the pivot arm 50 in stopping the retraction of the flexible shaft 24 and plastic sleeve 26 for a range of different diameters. The adjustability provided by yoke 60 permits the upper roller 58 to be moved up and down to account for shaft wear as well as different size shafts. In general, the step down from the flexible plastic sleeve to the core of the flexible shaft is fairly consistent between most flexible shaft sizes, so the yoke 60 allows setting of a neutral position so that the mechanical linkage detects the step down no matter the particular flexible shaft being used.

[0045] In a pneumatic control system shown in FIGS. 3, 4 and 9, the retraction stop sensing provided by mechanical linkage 38 mechanically opens brush positioner vent valve 40 which corresponds to valve 1018 in FIG. 11. Brush positioner vent valve 40 receives air pressure via line 42. Brush positioner valve 40 is normally closed. Brush positioner valve 40 is opened by lateral force and/or a stem or probe applied to one side to allow air to be vented from line 42 to exhaust line 44. For example, brush positioner valve 40 can be a check valve or a linear valve. In mechanical linkage 38, when lower roller 52 rides on the smaller diameter flexible shaft 24 or the connector 22, the upper end 54 of pivot arm 50 is pulled by spring 56 towards vent valve 40 to cause vent valve 40 to open and vent air to exhaust line 44, stopping the retraction of the flexible shaft 24 and plastic sleeve 26. Vent valve 40 is operably connected via exhaust line 44 to an exhaust port 48. Blocking the exhaust port 48 (or in FIGS. 7-9, the exhaust port 148), for example with a thumb or finger, overrides the stop signal by allowing pressurization of the control system air lines, and permits operation of the reverse control valve by trigger switch 80 to cause retraction of the flexible shaft

[0046] In an electronic control system, shown in FIG. 12, the stop sensor 240 is a magnetic or mass or proximity sensor which senses when the upper end 254 of L-shaped pivot arm 250 has been positioned near the stop sensor 240, which happens when the brush assembly is sufficiently retracted that the lower roller 252 rides on the smaller diameter flexible shaft 24 or the connector 22, causing the upper end 254 of pivot arm 250 to be pulled rearwardly by spring 256, and positioning the upper end 254 near the stop sensor 240. When the microcontroller 2000 detects that the stop sensor has sensed the upper end 254 of pivot arm 250, microcontroller 2000 terminates its signal to the reverse electrical relay 2020 and thereby terminates operation of the drive motor and drive unit, stopping retraction of the sleeve, flexible shaft and brush. An override may be programmed into the microcontroller 2000 such that when both the forward and reverse control push button switches are pressed at the same time when the reverse stop is activated, the flexible shaft can be retracted further past the stop position into the protective casing and back to a storage reel.

[0047] Accordingly, the present invention provides an improved tube cleaning apparatus and brush positioner, which provides the user with a consistent retraction of the brush, with a sufficient extending brush that makes it easier for the operator to consistently guide the brush and brush positioner into a correct position to clean the next tube in a series. By using the protruding brush as a guide the operator can visually align and then insert the brush into the tube to be cleaned, thus minimizing errors in the alignment or positioning, and thus providing greater efficiency and a cost savings.

[0048] It is within the scope of the invention to utilize other control systems for the tube cleaning apparatus. For example, the pneumatic air pulses or signals issued from the control handle through air links to the air switches are illustrative embodiments and other specific, analogous means such as electric, mechanical or radio pulses or signals can be used through appropriate links to turn the drive motor on and off and to form part of the arresting gear described.