Abstract:
A water blast gun support apparatus and methods for enabling the operator to direct the gun by a joystick attached to a pneumatic sinusoidal biasing control unit. Depending upon the direction the joystick is pointed by the operator, a controlled flow of air is delivered to pneumatic motion producing actuators which move the water blast gun to the desired position and maintain this position when the operator moves the joystick to its neutral position. The support apparatus absorbs the thrust of the water so that the operator is relieved from having to physically counter the force of the water.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional application Ser. No. 60/650,839 filed on Feb. 8, 2005, the entire content of which is hereby incorporated by references. 

   FIELD OF THE INVENTION 
   This invention relates generally to portable and stationary support apparatus and methods for water blast guns and, more particularly, water blast gun support apparatus and methods for industrial and commercial cleaning such as cleaning exterior building wall surfaces, water towers, the interior and exterior of storage tanks, heat exchange tubes, ships, automotive paint lines and fixtures, etc. 
   BACKGROUND OF THE INVENTION 
   Water blast cleaning guns are used to clean exterior walls and the like. These guns are typically carried by and manually operated by a person. Operating such a gun is an especially fatiguing occupation since the user must constantly direct the blast while physically countering the force of the water or be is knocked backward by its force. Such fatigue often adversely affects the operator&#39;s ability to concentrate on directing the water blast at the surface that needs to be cleaned. 
   SUMMARY OF THE INVENTION 
   This invention is a portable or stationary support apparatus to which a water blasting gun is attached wherein the operator directs the gun by a joystick coupled to a positioning and control system. This apparatus absorbs the thrust of the water so that the operator of the gun is relieved from having to physically counter this force. This water blast gun apparatus and methods prevent the operator from being knocked backwards and injured by the thrust of the water, substantially reducing operator fatigue, substantially increasing his ability to concentrate on directing the water blast at the surface that needs to be cleaned, and allowing him to much more precisely maintain the water blast on a particular target. 
   In one embodiment, the joystick controls a pneumatic sinusoidal biasing control unit. Depending upon the direction the joystick is pointed by the operator, a controlled flow of air is delivered to pneumatic actuators which move a gun support arm to the desired position and maintain its position there. 
   This apparatus and methods advantageously provide the operator with a full range of motion while giving the operator full-time control as to where the operator points the gun and how much thrust the operator wants to feel. As a result, the operator has the same or better control of the water blast gun than the operator would by manually holding the blast gun plus the substantial advantage of not having to both support the weight of the gun and hose and exert an equal but opposite thrust to that created by the water blasting out of the gun. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of one embodiment of the water blast gun apparatus being used to clean the wall of a building. 
       FIG. 2  is a perspective view of another embodiment of the water blast gun apparatus. 
       FIG. 2A  is a perspective view of an alternate configuration of the water blast gun apparatus. 
       FIG. 3  is a side elevation view of the water blast gun apparatus of  FIG. 2 . 
       FIG. 4  is a top elevation view of the water blast gun apparatus of  FIG. 2 . 
       FIG. 5  is a perspective view of the actuator used to control rotation of the water blast gun in the horizontal plane. 
       FIG. 6  is another perspective view of the actuator apparatus of  FIG. 5  with the upright, overhead and control beams removed. 
       FIG. 7  is a top elevation view of  FIG. 5  illustrating the position of the actuator with the control arm at its midpoint of movement in the horizontal plane. 
       FIG. 8  is a top elevation view of  FIG. 7  with the beams removed. 
       FIG. 9  is a top elevation view of  FIG. 5  illustrating the position of the actuators when the control arm is at its extreme clockwise position. 
       FIG. 10  is a top elevation view of  FIG. 9  with the beams removed. 
       FIG. 11  is a top elevation view of  FIG. 5  illustrating the position of the actuators when the control arm is at its extreme counter-clockwise position. 
       FIG. 12  is a top elevation view of  FIG. 11  with the beams removed. 
       FIG. 13  is a perspective view of the joystick controlled pneumatic biasing control unit with the top cover removed to show the orthogonally positioned pneumatic proportioning valves. 
       FIG. 14  is a side elevation view of  FIG. 13  with the control unit cover replaced. 
       FIG. 15  is a sectional view of  FIG. 14  taken along line  15 - 15 . 
       FIG. 16  is another side elevation view of the joystick controlled pneumatic biasing control unit. 
       FIG. 16A  is the cross-sectional view E-E of  FIG. 16 . 
       FIG. 16B  is the cross-sectional view F-F of  FIG. 16 . 
       FIG. 16C  is the cross-sectional view G-G of  FIG. 16 . 
       FIG. 16D  is the cross-sectional view H-H of  FIG. 16 . 
       FIG. 17  is a simplified drawing of a portion of the joystick controlled pneumatic biasing control unit illustrating the apparatus and function of the rotary bearing. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  illustrates an embodiment of the water blast apparatus, applying a high pressure e.g., 10,000 to 40,000 psi, blast of water  35  against the wall  40  of an exterior building. The water is delivered under high pressure through hose  45  to a water blasting gun  50 . 
   Operator  55  is enabled to both easily control the direction of gun  50  and maintain its position. It will be understood that water guns under high pressures of the order of 10,000 psi and above are extremely difficult to control because the large thrust force produced by the high pressure water must be countered by an equal manual force provided by the operator. Even a very physically strong operator will soon become fatigued operating high thrust water blast guns. A feature of the preferred embodiment is that the water thrust force is absorbed by the apparatus and not the operator  55 . As a result, the operator has real time control as to where he or she points the gun  50  and can have as much or little thrust to counter as the operator wants to feel. 
   A trigger operated flow control valve  60  (shown being operated by the operator&#39;s right hand) is connected between the end of water hose  45  and the barrel  51  of gun  50 . The operator uses valve  60  to turn on and off the flow of water. 
   The operator&#39;s left hand grasps a joystick  75  to position the gun  50 . Joystick  75  controls a pneumatic control system that positions the control arm  100  attached to and supporting gun  50 . This system includes control unit  227 . Air flow hose  230  connects unit  227  to an air compressor  229  supplying air under pressure to unit  227 . Controlled air flows out of unit  227  are sent over plural air hose  228  to motion producing actuators  175  and at  120  as described below to drive the control arm  100 . Other pneumatic control devices, such as pilot-operated regulators and/or valves to allow for larger volumes of air to pressurize the actuators quickly, can be used to provide the operator with more instantaneous response. Such devices are coupled between the joystick and the motion producing actuators driving control arm  100 . These pilot-operated regulators and/or valves can be exchanged for smaller or larger capacity units, as requirements for more or less air flow dictate. 
   Control arm  100  is attached to a portable stand  105  including a horizontal base  110  shown supported on the ground. However, the base  110  may be attached to a trailer, truck, dolly, or other mobility apparatus, or may be fitted with wheels or treads to allow for self-contained mobility, or may be permanently or semi-permanently installed in a factory, process plant, shipyard, or other location as well. Vertical uprights  115   a ,  115   b  are attached at one end to base  110  and to a housing  120 . An overhead beam  125  is mounted at point  124  along its length for controlled rotational motion in the horizontal plane. At one end of beam  125  are counter balance weights  130 ,  131 . The downward extending control arm  100  is pivotally mounted at the opposite end of beam  125 . 
   Motion forward and backward of control arm  100  is produced by pneumatic actuator  175  attached at one end to beam  125  and at the other end to the arm  100 . Within the actuator  175  is a controllable piston (not shown) attached to piston rod  176 . As shown, the end of rod  176  is pivotally attached to control arm  100  at a point below the piston pivot axis of control arm  100 . As piston rod  176  is caused to translate by the controlled piston within actuator  175 , the control arm  100  is caused to move forward and backward and thus change the fore and aft position of the gun  50 , and hold the desired position. 
   A rotary motion producing pneumatic actuator is located within housing  120 . This rotary actuator drives a vertical shaft connected to beam at point  124 . As this rotary actuator is caused to rotate in a clockwise or counterclockwise direction, control arm  100  is caused to move in a circular path to the right or left of the operator  55 . 
   An alternative embodiment of the water blast support apparatus is shown in  FIGS. 2 ,  2 A,  3  and  4 . Control arm  200  is pivotally mounted at its upper end to pivot on axis  307  at the end of overhead beam  225 . An assembly  226  including the barrel  51  of water blast gun  50 , proportioning pneumatic valve control unit  227  and attached joystick  75  is attached at the lower end of control arm  200 . The trigger operated valve  60  turns the volume of high pressure water on and off through barrel  51  from a water hose  45  (see  FIG. 1 ) attached to the proximal end  52  of gun  50 . The hose can be alternately attached to any number of locations to improve the handling of the unit. 
     FIG. 4  is a top elevation view of the water blast gun being held by an operator. In this illustration the linear actuator is oriented in the same direction as the tip of the gun. In the neutral position the operator pushes the joystick forward (+x direction) to signal the linear actuator to apply force to in the +x direction. Pushing the joystick to the right (+y direction) signals the rotary actuator to apply force in the clockwise location. If the operator repositions himself by turning the gun ¼ turn clockwise then the signals to the actuators must be translated. Pushing the joystick forward (now in the +y direction) signals the rotary actuator to apply force in the clockwise direction. Pushing the joystick to the right (−x direction) signals the linear actuator to apply force in the −x direction. The operator can reposition himself from the neutral position by turning the gun clockwise by 30 degrees. To maintain the force balance along the direction of the gun the forward thrust of the joystick must be biased between both the linear and rotary actuator. The signal to the linear actuator is multiplied by the cosine of 30 degrees (0.866) and the signal to the rotary actuator is multiplied by the sine of 30 degrees (0.50). This maintains the balance between the two actuators as the operator repositions the gun relative to the support mechanism. The construction of the valve is such that the biasing control is calculated mechanically. The geometry follows a sinusoidal relationship hence the term “sinusoidal biasing”. The unique design allows the operator to maintain the same motions for forward, back, left and right regardless of the direction of the waterblast gun assembly. The operator is free to rotate around the axis of the control arm  200 . 
   The joystick  75  is connected to the water blast gun  50  by member  400  and  455  (see illustration  13 ). The coordinate system of the joystick  75  can be defined based on the axis of the gun barrel  51 . Motion of the joystick forward along the axis of the barrel is defined as +x′. Motion perpendicular is +/−y′. As the water blast gun  50  rotates about the vertical member  200  the joystick  75  rotates along with the water blast gun  50 . The coordinate system noted by x′, y′ is defined by the position and rotation of the water blast gun  50  and joystick  75  relative to the water blast support apparatus and is moveable. The only time the coordinate systems of the water blast gun  50  and the water blast support apparatus defined as X, Y, are aligned is shown by  FIG. 4 . 
   The water blast gun  50  is free to rotate about the axis of the vertical member  200 . As it rotates the joystick  75  is oriented in the same direction as the axis of the gun barrel  51 . In the neutral position shown in  FIG. 4  the operator  55  pushes the joystick  75  forward in the +x′ direction of the gun barrel  51  to actuate valve  430  and signal the linear motion actuator  275  to apply force in the +X direction of the water blast support apparatus. Pushing the joystick  75  to the right in the +y′ direction actuates valve  420  and signals the rotary actuator assembly  120  to apply force in the clockwise direction. 
   If the operator  55  rotates the water blast gun  50  about the axis of the vertical member  200  one quarter turn clockwise (+90 degrees) the signals to the actuators must be translated. The operator  55  resists the force of the water blast gun  50  by pushing the joystick  75  forward in the +x′ direction relative to the gun barrel  51 . This motion now actuates valve  420  and signals the rotary actuator assembly  120  to apply force in the clockwise direction. Pushing the joystick to the right in the +y′ direction relative to the gun barrel  51  actuates valve  431  and signals the linear motion actuator  275  to apply force in the −X direction relative to the water blast support apparatus. 
   In a third example the operator  55  can reposition the water blast gun  50  clockwise by 30 degrees about the axis of the vertical member  200  from the neutral position of  FIG. 4 . The operator  55  continues to resist the force of the water blast gun  50  by pressing forward on the joystick  75  in the +x′ axis of the gun barrel  51 . To maintain the force balance along the axis of the gun barrel  51  the signals must be biased between both the linear motion actuator  275  and rotary actuator assembly  120 . Based on this example, the displacement of the joystick is multiplied by the cosine of 30 degrees (0.866) to determine the stroke of valve  430  and multiplied by the sine of 30 degrees (0.50) to determine the stroke of valve  420 . This maintains the balance between the two actuators  275  and  120  as the operator  55  repositions the water blast gun  50  relative to the support mechanism. The construction of the valve assembly  226  is such that the biasing control is calculated mechanically. The geometry follows a sinusoidal relationship hence the term “sinusoidal biasing”. This unique design allows the operator  55  to maintain the same motions for forward, back, left and right regardless of the direction of the water blast gun assembly  50 . 
   Portable stand  205  includes a base structure  210 . A modified base  210   a  is shown in  FIG. 2A . Uprights  215   a ,  215   b  are attached at one end to base  210  and at their other end to the bearing support plate  216  (shown in  FIG. 8 ). 
   A generally U-shaped upright beam assembly  300  (best shown in  FIG. 2A ) is rotatably mounted to a controllable rotary actuator located within housing  120 . Overhead beam  225  is rigidly attached to one end of a pivot beam  305 . The opposite end of beam  305  is pivotally mounted to upright beam  300  around an axis defined by axle  306 . A shroud  301  shown in  FIG. 2  may substantially cover enclose pivot beam  305 . 
   Controlled movement of control arm  200  left, right, up and down (and corresponding controlled movement of the water blaster gun  50 ) is provided by a pneumatic actuator system including linear motion producing actuators  275  and  280 . One end of actuator  275  is pivotally attached to beam  225  to pivot on axis  290 . Extending from cylinder  275  is a controlled piston rod  295  whose end is pivotally attached to control arm  200 . Thus, controlled linear movement of rod  295  results in a controlled pivotal movement and/or maintenance of a static position of control arm  200  around pivot axis  307 . 
   The cylinder  310  of the second pneumatic actuator  280  is pivotally mounted to overhead beam  225 . The end of linear drive rod  315  of actuator  310  is attached to upright  300 . Accordingly, controlled linear motion of rod  315  results in motion of the attached beams  200 ,  225  and  305  around axis  306 . Actuator  280  thus provides controlled vertical up and down movement of the gun  50 . 
   Controlled motion of gun  50  in the left and right directions is achieved by controlled rotation of beam  300  by a pair of pneumatic cylinders and bell crank located within housing  120 . The apparatus for controlled rotary motion of control arm  200  is shown in  FIGS. 5-12 . Referring now to  FIGS. 5 and 6 , the housing  120  has been removed to expose the pneumatic linear actuators  350  and  355 . These actuators are located on opposite sides of bell crank  360 . One end of bell crank  360  is attached to shaft  370  rotatably mounted in bearing  365  with respect to base  205 . The opposite end of shaft  370  is attached to bottom plate  375  of upright beam  300  (see  FIGS. 2A and 6 ). The ends of respective piston rods  380 ,  381  of the actuators  350 ,  351  are pivotally connected to the other end of bell crank  360  to translate the back and forth controlled linear motion of the piston rods  380 ,  381  to controlled rotary motion of shaft  365 , and its attached upright beam  300 . Rotary motion of beam  300  results in translation of control arm  200  and gun  50  in left and right directions. Thus, translation of piston rod  380  out of cylinder  350  with corresponding translation of piston rod  381  into cylinder  355  results in clockwise rotation of upright beam  300  and movement of control arm  200  and gun  50  in the right-hand direction in the FIGURES. 
     FIGS. 7-12  illustrate the movement of overhead beam  225  as it is translated to its limits in a clockwise direction and in a counterclockwise direction. As shown in  FIGS. 7 and 8 , piston rods  380  and  381  are extended equal distances from their respective actuators  350 ,  351  and the overhead beam  225  is centered with respect to the base  205 . 
   In  FIGS. 9 and 10 , the piston end  380  is extended out from actuating to its maximum extension and piston rod  381  is withdrawn into its actuator  351  to its minimum extension to rotate beam  225  clockwise 45° from its center position shown in  FIGS. 7 and 8 . 
   In  FIGS. 11 and 12 , the piston rod  380  is withdrawn into its actuator  350  to its minimum extension and piston rod  381  is extended out from actuator  351  to its maximum extension to rotate beam  225  counterclockwise 45° from the center position shown in  FIGS. 7 and 8 . 
   The apparatus and operation of one embodiment of control unit  227  is illustrated in  FIGS. 13-17 . Joystick  75  is attached to the bottom member  401  of a rigid generally rectangular frame  400 . The proximal end  405  of a pneumatic slide actuator member  406  (shown in  FIG. 15 ) is rigidly attached to the top member  402  of frame  400 . Actuator member  406  includes a generally spherical surface  410  supported by a spherical bearing within the unit  227  such that movement of the joystick  75  will produce a similar movement of the actuator member  406 . The embodiment shown of control unit  27  is a pneumatic sinusoidal biasing system wherein movement of actuator member  406  is coupled to pneumatic proportional valves  420 ,  421  and  430 ,  431  located within unit  227  (best shown in  FIG. 13  and in  FIGS. 16A and 16B  (sections E-E and F-F of  FIG. 16 ). This operation is provided in the embodiment shown by the distal end  425  of slide actuator member  406 . End  425  is formed to function as a control rod that engages orthogonally positioned slide actuators  426  and  427 . See, e.g., slide actuator  426  in  FIG. 13  and in  FIG. 16A  and slide actuator  427  in  FIG. 13 . 
   Slide actuator  426  of unit  227  includes end members  435 ,  436  adapted to respectively engage valves  431 ,  430 . Referring to  FIG. 13 , as control rod  425  moves slide actuator  426  in the direction of arrow  432 , the force applied to valve  430  by member  436  is increased and the force applied to valve  431  by member  435  remains zero. This change in the output of air pressure through these orthogonally opposed valves  430 ,  431  is used as the control signal, i.e. controlled air pressure flows out of the slide valves of unit  227  actuate movement and/or maintenance of a static position of the pneumatic actuators  275 ,  280 ,  350 ,  351  to control and position arm  200  and gun  50  in the direction of arrow  432 . As the operator changes the direction of joystick  75 , the pneumatic control unit  227  changes the control signal pressures that are sent to actuators. 
   As shown in  FIGS. 13 and 14 , a gun support bracket  455  is attached to the bottom of the unit  227 . The barrel  51  of gun  50  is rigidly mounted within cylindrical opening  456  of bracket  455 . As shown, for example, in  FIG. 2 , the top cover plate  450  of pneumatic biasing control unit  227  is rigidly attached to the bottom end of control arm  200 . 
   The pneumatic proportioning slide valves  420 ,  421  and  430 ,  431  thus control the air pressure to the respective pneumatic actuators  275 ,  280 ,  350  and  355  described above such that operator movement of the joystick  75  results in controlled movement of the gun  50  to the desired position. When the joystick is returned to a neutral position, the unit  227  maintains the static position of control arm  200 . 
   A series of air flow hoses and other pneumatic control devices couple the pneumatic sinusoidal bias control unit  227  to the actuators  275 ,  280 ,  350 ,  355  which move the control arm  200 . Typically, an input hose delivers air at  100  psi to valve  227 . Four hoses, two of which are connected to valves  420 ,  421  and the other two connected to valves  430 ,  431 , deliver the controlled air provided by the orthogonal slide valves to the pneumatic actuators  275 ,  280 ,  350  and  355 . 
   A feature of the pneumatic sinusoidal biasing control unit  227  is that the operator is free to rotate the gun on its mount; up, down, left, or right, and move the gun manipulator arm in any direction while the pneumatic sinusoidal biasing system is controlling arm  200 .  FIG. 15 ,  FIG. 16C  and  FIG. 17  illustrate the manner in which the joystick and its attached gun are free to rotate with respect to the arm  200 . The pneumatic sinusoidal biasing control unit  227  includes a ball bearing  500 . The outer race of bearing  500  is attached to housing of the pneumatic slide valves  420 ,  421 ,  430  AND  431 . Accordingly, these valves are fixed relative to control arm  200 . Joystick  75 , gun support bracket  455  and actuator member  406  are attached to the inner race of bearing  500  and are thus free to rotate relative to control arm  200 . Thus, at any position of the control arm, the operator is free to swivel the gun barrel right or left in ball bearing  500 , and up or down in the gun mount yoke while directing and controlling its counter thrust and position by pointing the joystick in the desired direction. The operator does not need to constantly readjust his x-y orientation, but the pneumatic sinusoidal biasing control valve does this for him. 
   The gun apparatus and methods described above counter operator fatigue while giving the operator substantial freedom in controlling the gun. Thus, the operator can “drive” the gun  50  left, right, up or down, and/or maintain a static position, without losing the ability to reduce the net thrust the operator feels from the water blast gun. Moreover, at any angle, the biasing mechanism gives the operator an intuitive control interface. 
   The above presents a description of the best mode contemplated for carrying out the water blast gun apparatus and methods in such full, clear, concise and exact terms as to enable any person skilled in the art to which it pertains to make and use this apparatus and practice these methods. While the pneumatic biasing control unit described above advantageously provides a sinusoidal bias control signals, other pneumatic biasing control units including linear bias units could be utilized in embodiments of the inventions. Also, while the embodiments of control system described above have involved a pneumatic control system, it will, however, be apparent that other embodiments are possible that utilize electrical or hydraulic or in combination with pneumatic components. Consequently, this water blast gun support apparatus and methods are not limited to the particular embodiments disclosed. On the contrary, these water blast gun support apparatus and methods cover all modifications and alternative constructions coming within the spirit and scope of this invention.