Abstract:
A sprayer for providing a regulated flow of material to a gun includes apparatus for fixing a substantially-cylindrical stator to a circular port of a pump housing block. Such apparatus includes a pair of clips that are pivotally fixed to the exterior of the pump housing block. The clips are diagonally spaced with respect to the port. Apertures are arranged in the pump housing block to receive crimped portions of the clips to engage apertures within the surface of a collar fixed to an end portion of the stator. By fixing the stator to the pump housing block in a manner that is not subject to rotation, rotation of the rotor with respect to adhesive rubber material within the stator when torque is manually applied to the rotor.

Description:
REFERENCE TO RELATED APPLICATION  
       [0001]    The present application is a continuation-in part of patent application Ser. No. 11/450,812 of inventor Eran Zagorsky titled “Sprayer For Application of Textured Finish to Surfaces” filed Jun. 12, 2006 in the United States Patent and Trademark Office. 
     
     BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to sprayers for use in the application of textured finishes to surfaces. More particularly, this invention pertains to a convenient and user-friendly sprayer unit for jobs of relatively-limited scope. 
         [0004]    2. Description of the Prior Art 
         [0005]    Texture spray equipment for use in small and medium size jobs that offers quick set-up, easy disassembly, compactness, portability and interchangeability of parts for quick, inexpensive repair has been developed over the years to address the inadequacies of bulky drywall material spraying systems for pumping liquids at job locations. Such bulky systems require mounting onto vehicles or trailers for ease of transportation and are characterized by, for example, large storage tanks that render their usage economical only for large jobs. 
         [0006]    Examples of such spray equipment for smaller jobs include the sprayer taught by U.S. Pat. No. 5,967,426 of McLoed covering “Knockdown portable Liquid Drywall Material Spray System and Apparatus” and others. Such systems are typically mounted on a wheelable cart-like frame and interact with a compressor to provide a controllable spray of material for adhering onto a surface. 
         [0007]      FIG. 1  is a schematic view of a generalized texture deposition system  10  of the type discussed above. The sprayer  11  of the sprayer system is indicated in broken outline. A hopper  12  is arranged to receive input material  14  for eventual deposition onto a surface. The material (e.g. drywall)  14  is transferred, generally by means of gravity feed, into a pump  16  of the screw-feed (rotor and stator) type. The pump  16  advances the received material  14  linearly toward a nozzle  18 , in response to the output of an electric motor  20  whose speed and power are selectively controlled by means of a control box  22 . 
         [0008]    A hose  24  is fitted to the nozzle  18  to receive the material  14  at a predetermined flow rate. The material hose  24  feeds the flowing material to a gun  26 . A second input to the gun  26  comprises an air flow generated by a compressor  28  and delivered through an air hose  30 . The relative flow parameters of material  14  through the material hose  24  and air through the air hose  30  to the gun  26  determine the thickness and texture of the resultant material deposited upon a surface. 
         [0009]    While texture deposition systems as described above may be configured for suitability for small and medium sized jobs, such equipment is often not user friendly. Although relatively portable, operation of such wheeled equipment is complicated by such limitations as spillage of material from the hopper  12  and shorting of the circuitry of the control box  22  as a result of weather. Furthermore, the sprayer  11  often requires disassembly of the pump  16  after period of extended non-use as a result of adhesion of the internal rotor to a surrounding layer of rubber within the stator. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention addresses the preceding and other shortcomings of the prior art by providing apparatus for fixing an elongated, substantially-cylindrical stator to a pump housing block of a sprayer. 
         [0011]    Such apparatus includes a collar fixed exterior and adjacent an end of the stator. The collar has at least one indentation arranged about the circumference of the stator. At least one clip that includes a crimped portion is pivotally engaged to the exterior of the pump housing block. 
         [0012]    At least one aperture is provided in the pump housing block. Such aperture is located with respect to a clip so that the crimped portion of the pivotally-mounted clip protrudes within the interior of the pump housing block when the clip is rotated to a closed position to engage an indentation of the collar. 
         [0013]    The foregoing and other features of the invention will become further apparent from the detailed description below. Such description is accompanied by a set of drawing figures. Numerals of the drawing figures, corresponding to those of the written description, point to the features of the invention with like numerals referring to like features throughout. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a schematic view of a sprayer system in accordance with the prior art; 
           [0015]      FIGS. 2   a  through  2   c  are a perspective view, a partially exploded side elevation view and an exploded perspective view of the cover assembly, respectively, of a sprayer in accordance with an embodiment of the invention; 
           [0016]      FIGS. 3   a  through  3   c  are a side sectional view of the pump, a frontal view of the free end of the cartridge shaft and an enlarged exploded perspective view of the relationship of the pump to the stator assembly respectively, of a sprayer in accordance with an embodiment of the invention; 
           [0017]      FIGS. 4   a  and  4   b  are perspective views in juxtaposition of the hopper and the transport frame, respectively, of a sprayer in accordance with an embodiment of the invention; and 
           [0018]      FIG. 5  is a perspective view of a removable control box engaged to the frame of a sprayer in accordance with an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0019]      FIGS. 2   a  through  2   c  are a perspective view, a partially exploded side elevation view and an exploded perspective view of the cover assembly, respectively, of a sprayer in accordance with an embodiment of the invention. Such a sprayer includes numerous user-friendly features that facilitate maintenance, portability and usability. As a result, the device of the invention further advances the ability of a user to complete low volume texturizing jobs in an efficient manner and absent the “overkill” of large-scale systems. 
         [0020]    As seen in  FIG. 2   a,  the sprayer  32  comprises two main functional units, a hopper  34  for receiving material and pump  36  whose operation is powered by an electric motor  38 . (A control box for controlling the operation of the motor  38  cannot be seen in  FIG. 2   a  but is described and illustrated below.) The entire sprayer assembly is mounted on a frame  40  that includes a pair of wheels  42  (only one of which is visible in  FIG. 2   a ) that are aligned and rotatable about a common axis  44 . The tubular frame  40  includes legs  46 ,  48  for stabilizing the sprayer  32  at rest and a handle for facilitating ready transport. As will be seen below, the hopper  34  is designed to facilitate transport of the sprayer  32  despite the presence of material within the hopper  34  while the design of the frame  40  facilitates the cooperative engagement of a removable control box, thereby permitting the sprayer  32  to be left outside during inclement weather that would otherwise subject the control electronics of the sprayer  32  to damage. 
         [0021]    A guard  52  overlies the mechanism whereby the output of the motor  38  drives the pump  36 . Such mechanism will be appreciated by additional reference to  FIGS. 2   b,  a partially-exploded side elevation view of the sprayer  32 , and  2   c,  an exploded perspective view of the guard  52  including associated mechanisms. Referring to  FIGS. 2a through 2   c  now in combination, the motor  38  is fixed to a bracket mount  54  so that the output drive shaft  56  of the motor is arranged to protrude through a v-shaped opening  58  at the bottom of an inner cover  60  that includes a peripheral edge  61 . A planar outer cover  62  is fixed to the inner cover by means of cap screws  64  whereby opposed planar surfaces of the inner and outer covers  60 ,  62  are maintained in parallel spacing defined by the height of the peripheral edge  61  of the inner cover  60 . 
         [0022]    A mentioned earlier, the drive shaft  56  of the motor  38  is aligned to protrude within the region formed between the inner and outer covers  60  and  62  at the v-shaped opening  58 . A small gear is fixed to the end of the drive shaft  56  to engage a timing belt  68  for driving a large gear wheel  70 . The large gear wheel  70  will be seen below to be fixed to an end of a drive train for driving the pump  36 . 
         [0023]    An annular hub  72  is located at the center of the large gear wheel  70  for coupling to a cartridge shaft (not shown) at the end of the drive train of the pump. A upper aperture  74  within the rear cover  60  is aligned with both the center of the annular hub  72  and with an aperture  76  within the front cover  62 . As a result, the end of the cartridge shaft is aligned with the aperture  76  when fixed to the annular hub  72 . Accordingly, the end of the cartridge shaft is thereby accessible, through the aperture  76  of the front cover  62 , without disassembly of the guard  52 . 
         [0024]    Reference is now made to  FIGS. 2   b  and  3   a,  a side sectional view of the pump  36  of a sprayer in accordance with an embodiment of the invention, in combination. As can be seen, the pump  36  includes a pump pump housing block  78  having an upstanding input port  80  for receiving gravity-fed material from the overlying hopper  34 . A cartridge tube  82  and a stator  84  are engaged to opposed ends of the pump housing block  78 . The pump housing block  78  includes an internal elongated passageway  86  within which is located a pump drive train comprising, in combination, aligned elongated elements including a rotor  88 , a connecting rod  90  and a cartridge shaft  92 . The cartridge shaft  92  comprises and elongated member consisting of three adjoining cylindrical elements of successively reduced diameter (when one proceeds outwardly from the interior of the pump housing block  78 ). It is centered for rotation within the internal elongated passageway  86  of the pump housing block  78  by means of an inner bearing  94  and an outer bearing  96 . 
         [0025]    The connecting rod  90  is joined to the cartridge shaft  92  and to the rotor  88  by means of dowel pins  98 ,  100 . The stator  84 , of conventional design, includes a filled rubber interior  101  within which the rotor  88  is aligned for rotation along the central axis of the elongated internal passageway  86  of the pump housing block  78 . Accordingly, the axes of rotation of the elongated rotor  88 , the connecting rod  90  and the cartridge shaft  92  are aligned within the pump housing block  78 . A collar  102  of molded elastomeric material surrounds the end portion of the stator  84  that seats within the pump housing block  78 . The collar  102  is rigidly fixed to the stator  84  by a combination of threading and adhesive, effectively forming a single piece, discussed below. 
         [0026]    The free end  103  of the cartridge shaft  92  is polygonal, preferably hexagonally-shaped as seen in  FIG. 3b , a frontal view of the free end of the cartridge shaft  92 . In the prior art, the rubber of the filled rubber interior  101  of the standard stator  88  is known to adhere to the rotor  88  during periods of non-use. As a consequence, disassembly of the pump  36  has been required to render the sprayer operational. Such disassembly can be tedious and time-consuming. To overcome this difficulty, the free end  103  of the cartridge shaft  92  comprises a polygonal shape in the present invention that may be engaged by an appropriately-shaped socket wrench. Further, the cylinder shaft  92  is positioned in alignment with the aperture  76  within the outer cover  62  of the guard  52 . As result, the free end  103  may be engaged by such a socket wrench without any disassembly. Once so engaged, the user can free the rotor from adhesion to the filled rubber interior  101  of the stator  84  by applying manual (or mechanical) force to the wrench to cause the entire aligned, elongated pump drive assembly comprising the cylinder shaft  92 , the connecting rod  90  and the rotor  88  to rotate the rotor  88  a sufficient amount with respect to the filled rubber interior  101  to break the adhesion force. 
         [0027]    The relationship between the pump housing block  78  and the stator  84  (with collar  102  fixed thereto) is illustrated in the exploded perspective view of  FIG. 3   c.  As shown, the molded collar  102  includes a plurality (four) of partially-circumferential indentations  104 . Such indentations  104  are arranged to accommodate the crimped portions  106  of clamps  108  that are pivotally-mounted to the exterior of the pump housing block  78 . Apertures are  110  provided in the body of the pump housing block  78  to admit the crimped portions  106  of the clamps  108  when rotated to their “closed” positions (the clamp  108  is illustrated in the “open” position in  FIG. 3   c ). 
         [0028]    The stator  84  is fixed to a circular port of the pump housing block  78  by insertion of the end that includes the molded collar  102  with the clamps  108  in the open position illustrated in  FIG. 3   c.  This is followed by rotation of the collar  102  (and stator  84 ) to assure that slots  104  are aligned with the apertures  110  for admitting the crimped portions  106  of the clamps  108 . Thereafter, the pivotally-mounted clamps  108  are rotated to their closed positions whereby the crimped portions  106  protrude through the apertures  110  into aligned peripheral indentations  104  of the collar  102 . Thus, the substantially-cylindrical stator  84 , held and releasable by means of the clamps  108 , is readily insertable and removable with respect to the pump housing block  78  via pure axial movement along its axis of symmetry. By securing the stator  84  to the pump housing block  78  by means of the clamps  108  that seat in indentations  104  that block potential rotation of the stator  84 , rather than threadedly engaging stator  84  and pump housing block  78 , the stator  84  is prevented from rotating in response to rotational forces transmitted from the rotor  88  via the filled rubber interior  101  of the stator  84 . Such forces can be transmitted when, through a long period of non-use of the sprayer, the filled rubber interior  101  is caused to adhere to the surfaces of the rotor  88  and the stator  84 . Should such adhesion of the filled rubber interior  101  cause the stator  84  to rotate with the rotor  88 , material cannot be advanced through the stator  84 , causing the sprayer to cease to function. 
         [0029]      FIGS. 4   a  and  4   b  are perspective views in juxtaposition of the hopper and the transport frame of a sprayer in accordance with an embodiment of the invention. The hopper  34  comprises an integral molded structure of plastic or other synthetic composition that defines a volume within an interior bounded by a front panel  112 , opposed side panels  114  and  116 , and a rear panel  118 . The height of the rear panel  118  exceeds that of the front panel  112 . Accordingly, the edges of side panels  114  and  116  that intersect the rear panel  118  are of greater than those that intersect the front panel  112  as shown. A lid  120  protrudes from the top of the rear panel  118  and adjoins the extended regions of the side panels  114 ,  116  having heights approximately equal to that of the rear panel  118 . 
         [0030]    Viewing the hopper  34  in conjunction with the juxtaposed frame  40 , one can see that the hopper  34  is aligned with respect to the transport frame so that the rear panel  118  lies against upstanding tubular frame members  122 ,  124  that define the back of the frame  40 . Such members  122 ,  124  are positioned to rotate about the axle  44  common to the paired wheels  42 . The permits the user to transport the sprayer by rotating the handle  50  downwardly and pushing the device. The lid  120  that covers the rear portion of the hopper  34  prevents the overflow of material from the hopper  34  during such transport. Thus, unlike other knockdown sprayers, one may relocate the sprayer of the invention without first emptying the hopper of drywall or other material prior to manual transport. This additionally simplifies and facilitates the use of the invention. 
         [0031]    As can be seen in  FIG. 4   b,  a generally u-shaped flange member  126  is fixed to the handle  50  of the frame  40 . Such member  126  is provided for engaging a mounting bracket  128  fixed to a control box  130  as illustrated in  FIG. 5 . The control box  130  provides the switches for adjusting the direction and speed of the electric motor  38  that, in turn, controls operation of the pump  36 . While of standard design, it is significant that the control box  130  of a sprayer in accordance with an embodiment of the invention is fully removable, allowing its ready removal upon decoupling of associated cabling  132  from other elements of the sprayer. This permits one to then lift the control box  130  from the generally u-shaped flange  128  at the rear of the frame  40  for interior storage while the sturdy remainder of the sprayer is left outside. Again, this feature, a control box  130  removably fixed to the frame of the sprayer, further facilitates the use of the invention. 
         [0032]    Thus it is seen that the present invention provides a user friendly sprayer of the knockdown type. By employing a sprayer in accordance with the claimed invention, the user enjoys numerous user-friendly features. Such features avoid any need to disassemble the sprayer pump after periods of prolonged non-use, permit manual transport of the sprayer while drywall or other material is present in the hopper and allow the device to be left outside during inclement weather. 
         [0033]    While the invention has been described with reference to a presently-preferred embodiment, it is not limited thereto. Rather, the invention is limited only insofar as it is defined by the following set of patent claims and includes within its scope all equivalents thereof.