Patent Document

BACKGROUND  
         [0001]    The invention relates to cleaning devices and more particularly devices for cleaning paint spray guns.  
         SUMMARY  
         [0002]    The present invention provides an apparatus for cleaning a spraying end of a paint sprayer. The apparatus includes a solvent vessel having an opening and containing a solvent. The opening is configured to receive the spraying end of the paint sprayer. A rotatable brush is only partially submerged in the solvent such that the spraying end contacts the brush when the spraying end is inserted into the opening. A motor (e.g. a pneumatic motor)is interconnected with and provides rotation to the brush. A signal generator is operable to provide an actuation signal that activates the motor such that the brush rotates and cleans paint from the spraying end of the paint sprayer.  
           [0003]    The brush preferably includes a plurality of flexible bristles and is mounted within the vessel such that a portion of the brush is below the solvent level and a portion of the brush is above the solvent level. Preferably, the motor is configured to rotate the brush in alternating directions each time the spraying end is inserted into the opening. The brush preferably rotates about a substantially horizontal brush axis that is below the solvent level and the spraying end may be inserted into the opening substantially perpendicularly to the brush axis. The spraying end preferably contacts an outer surface of the brush during cleaning.  
           [0004]    The signal generator may include a limit switch that is positioned adjacent the opening. The limit switch may be configured to provide the actuation signal in response to insertion of the spraying end into the opening. The vessel may also include a top wall and the opening may be smaller than the top wall.  
           [0005]    The present invention also provides a method for cleaning a spraying end of a paint spray gun. The method includes providing a solvent vessel defining a chamber that contains a solvent at a solvent level. A rotatable brush is partially submerged in the solvent within the vessel such that a portion of the brush is above the solvent level. The spraying end of the paint spray gun is inserted into the chamber through the opening and the brush is rotated. The spraying end engages the exposed portion of the brush and paint is removed from the spraying end.  
           [0006]    A motor may be operably connected to the brush, and a limit switch may be provided that communicates with the motor. The limit switch preferably operates in response to the insertion of the spraying end into the chamber. In this regard, the limit switch signals the motor to rotate upon insertion of the spraying end into the chamber.  
           [0007]    The present invention also provides a paint spraying system for electronically controlled painting of a product. The system includes an enclosure, a conveying apparatus for conveying the product through the enclosure, and an electronic controller. A manipulator is positioned within the enclosure and operates in response to signals received from the electronic controller. The manipulator is operable to provide movement in a plurality of directions to a paint spraying nozzle that is coupled to the manipulator for movement therewith. A cleaning box is positioned within the enclosure and contains a solvent. The cleaning box includes an opening and houses a rotatable brush. A signal generator communicates with the rotatable brush and the brush rotates in response to an actuation signal provided by the signal generator.  
           [0008]    In response to receiving a cleaning signal from the controller, the manipulator inserts the paint spraying nozzle through the opening and into the cleaning box. The signal generator signals the brush to rotate, and the nozzle contacts the rotating brush such that paint is cleaned from the nozzle. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is a rear left perspective view of a paint spray gun cleaner embodying the present invention.  
         [0010]    [0010]FIG. 2 is a front right perspective view of the paint spray gun cleaner.  
         [0011]    [0011]FIG. 3 is a top view of the paint spray gun cleaner with the lid in an open position.  
         [0012]    [0012]FIG. 4 is a section view taken along line  4 - 4  of FIG. 1.  
         [0013]    [0013]FIG. 5 is a perspective view, with a portion cut away, of an automated paint spraying booth including a paint spray gun cleaner of the present invention. 
     
    
       [0014]    Before one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The use of “consisting of” and variations thereof herein is meant to encompass only the items listed thereafter. The use of letters to identify elements of a method or process is simply for identification and is not meant to indicate that the elements should be performed in a particular order.  
       DETAILED DESCRIPTION  
       [0015]    [0015]FIGS. 1 and 2 illustrate a paint spray gun cleaner  10  of the present invention. The cleaner includes a solvent container  12  supported by a leg  16  that is secured to or supported by the floor of a paint spraying area. A lid  20  is pivotally coupled to the container  12  by hinges  22  and is movable between an open position and a closed position. The lid  20  includes an aperture  24  that provides access to the container  12  when the lid  20  is in the closed position. A latch  26  is also provided to secure the lid  20  in the closed position. A pneumatic motor  28  is secured to an external side wall  30  of the container  12  and is coupled to air lines  32 A,  32 B. A signal generator in the form of a limit switch  36  is mounted to the lid  20  and electrically communicates with an air solenoid  40  through wires  44 . The air solenoid  40  receives compressed air from an air compressor (not shown) and cooperates with the limit switch  36  to regulate the delivery of the compressed air to the pneumatic motor  28  as described further below.  
         [0016]    Referring now also to FIGS. 3 and 4, the pneumatic motor  28  includes a rotatable drive shaft  48  extending through the side wall  30  and into the container  12 . A brush  52  is secured to the end of the drive shaft  48  for rotation therewith about a brush axis  56 . The brush  52  includes a plurality of bristles  60  extending radially from the brush axis  56 . In some embodiments, the bristles  60  are constructed of Nylon®. An appropriate brush  52  for use with the present invention is available from McMaster-Carr Supply Company of Elnhurst, Ill. as Item #4747A62.  
         [0017]    The container  12  is partially filled with a liquid solvent solution  64  to a solvent level  68 . The solvent level  68  is regulated such that a submerged portion  72  of the brush  52  is below the solvent level  68  and submerged in the solvent solution  64 , and an exposed portion  76  of the brush  52  is above the solvent level  68  and not submerged in the solvent solution  64 . The solvent level  68  is preferably maintained above the drive shaft  48  for optimal performance of the spray gun cleaner  10 . A suitable solvent solution  64  for use with the present invention is Poly-Purge® brand solvent solution, which is available from PPG Industries, Inc. of Pittsburgh, Pa.  
         [0018]    The spray gun cleaner  10  is particularly well suited for use in an automated paint spraying line  80  as illustrated in FIG. 5. The spraying line  80  includes an enclosure  84  having a product conveyor  88  passing therethrough. The conveyor  88  is of conventional design and conveys a product  92  from one end of the enclosure  84  to the other. The spraying line  80  also includes an electronically controlled manipulator  96  operating in response to signals received from a controller  100 . The manipulator  96  includes an end effector  104  that has a paint spraying nozzle  108 . The manipulator  96  guides the end effector  104  along a predetermined path to apply paint to the product  92  as the product  92  is conveyed through the enclosure  84 .  
         [0019]    As the paint spraying nozzle  108  sprays paint upon the individual products  92 , paint begins to accumulate on a tip  112  of the nozzle  108 . If an excessive amount of paint accumulates on the tip  112 , the quality of the paint spraying operation will be adversely affected and the aesthetic appearance of the finished product  92  will degrade. To avoid this situation, the controller  100  is programmed to provide a cleaning signal to the manipulator  96  after a predetermined quantity of product  92  has been painted. Upon receiving the cleaning signal, the manipulator  96  guides the end effector  104  toward the spray gun cleaner  10 .  
         [0020]    As best illustrated in FIG. 4, the manipulator  96  inserts the nozzle  108  through the aperture  24  in the lid  20 , and into the container  12 . The nozzle  108  is inserted substantially vertically in the illustrated construction, but may be inserted at an angle in alternate constructions. In any event, it is preferred to insert the nozzle  108  substantially perpendicularly to the brush axis  56 .  
         [0021]    As the tip  112  engages the bristles  60  of the brush  52 , a portion of the end effector  104  contacts a trigger  114  on the limit switch  36 . As the end effector  104  engages the trigger  114 , an actuation signal is provided to the air solenoid  40  via the wires  44 . Upon receipt of the actuation signal, the solenoid  40  opens the first air line  32 A (see FIGS. 2, 3) that communicates with an impeller (not shown) of the pneumatic motor  28  on a first side of the brush axis  56 . Pressurized air flows from the solenoid  40  toward the pneumatic motor  28  and impinges upon and thereby rotates the impeller in a first direction. The impeller is coupled to the drive shaft  48  such that rotation of the impeller imparts rotation to the brush  52 .  
         [0022]    As the brush  52  rotates, solvent solution  64  is applied to the tip  112  of the nozzle  108  by the exposed bristles  60 . The solvent solution  64  thins the paint on the tip  112 , and the bristles  60  loosen and remove the thinned paint from the tip  112 . The bristles  60  then rotate back into the solvent solution  64  where the paint is subsequently rinsed from the bristles  60 . The bristles  60  then rotate out of the solvent solution  64  to once again apply solvent solution  64  to the tip  112  and further clean the nozzle  108 .  
         [0023]    The tip  112  is maintained in contact with the rotating brush  52  for a predetermined amount of time to clean at least a portion of the paint from the tip  112 . After the tip  112  has been sufficiently cleaned, the controller  100  signals the manipulator  96  to remove the nozzle  108  from the container  12 , thereby disengaging the end effector  104  from the trigger  114  of the limit switch  36 . The solenoid  40  then stops the flow of air to the pneumatic motor  28 , thereby halting rotation of the brush  52 . The manipulator  96  then guides the nozzle  108  toward the product  92  to perform additional painting operations.  
         [0024]    Each time the predetermined quantity of product  92  has been painted, the manipulator  96  returns the nozzle  108  to the spray gun cleaner  10 . The solenoid  40  is configured such that each subsequent insertion of the nozzle  108  into the container  12  results in rotation of the brush  52  in alternating directions. Specifically, the solenoid  40  alternately provides compressed air to the pneumatic motor  28  via the first air line  32 A as described above, and the second air line  32 B. The second air line  32 B delivers compressed air to the pneumatic motor  28  such that it impinges upon the impeller on a second, opposite side of the brush axis  56  as the air from the first air line  32 A. As such, delivery of compressed air to the motor  28  through the first air line  32 A rotates the brush  52  in one direction (e.g. counter-clockwise) and delivery of compressed air to the motor  28  through the second air line  32 B rotates the brush  52  in an opposite direction (e.g. clockwise).  
         [0025]    Alternating the direction of rotation of the brush  52  in this manner results in improved cleaning of the tip  112  and longer life of the brush  52 . For example, a first insertion of the tip  112  into the container  12  will generally clean one side of the tip  112  more completely than the other side of the tip  112 . Similarly, the bristles  60  are flexed or bent in one direction as they contact the tip  112 . A second insertion of the tip  112  into the container  12  will generally clean the other side of the tip  112  that was less completely cleaned after the first insertion. Similarly, the bristles  60  will be flexed or bent in an opposite direction during the second insertion, thereby facilitating a more even wearing of the brush  52  and preventing the bristles  60  from becoming permanently bent in one direction.  
         [0026]    Alternatively, an electrically powered motor may be provided in place of the pneumatic motor  28 . The electric motor should be selected to have suitable size and power to impart the required rotation to the brush  60 . Appropriate control circuitry may be provided such that the electrical motor is capable of rotating the brush  60  in alternating directions substantially as described above with respect to the pneumatic motor  28 . Various other types of motors and control devices may be suitable as well, so long as they provide adequate alternating rotation of the brush  60 , substantially as described above.  
         [0027]    Furthermore, various other sensors, devices, and methods for controlling the activation of the motor may be utilized in accordance with the present invention. For example, non-contact type sensors including photocells, proximity sensors and the like may be adapted for use with the spray gun cleaner  10  to detect the insertion of the tip  112  into the container  12 , and provide an appropriate actuation signal to the air solenoid  40 . Alternatively, the controller  100  may be configured to provide an actuation signal to the solenoid  40  which corresponds to the sending of the cleaning signal to the manipulator  96 . In this regard, the actuation signal may be provided simultaneously with the cleaning signal, or may be delayed with respect to the cleaning signal to allow the manipulator  96  to reach the spray gun cleaner  10 . It should be appreciated that any actuation signal, whether provided by various types of limit switches or by the controller  100 , may be used to activate the motor  28 .  
         [0028]    Various features of the invention are set forth in the following claims.

Technology Category: 7