Abstract:
A combined prime valve and electrical pressure control apparatus including a prime valve actuator, an electrical pressure control actuator, and a control housing containing the actuators, with each coupled to a single shaft having a cam assembly for selectively actuating the control apparatus to one of a prime mode and a spray mode and the electrical pressure control is operable within a range of pressure settings by movement of the shaft while the control apparatus remains in the spray mode. The actuators are oriented diametrically opposite and offset along an axis of the single shaft with respect to each other, and contact the cam assembly and respectively contact a lever for a prime valve and a pressure switch carrier. A setscrew in the carrier provides adjustment of the pressure at which the switch is actuated.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to the field of paint spray pumps, particularly those which have a need for both a priming mode or function and an adjustable pressure mode or function while spraying after priming. 
         [0002]    Prior art pumps typically had a fixed pressure setting and switched from a priming mode to a spraying mode at the fixed pressure setting. Other prior art pumps had a pressure adjustment mechanism separate from the prime/spray control. The present invention provides an improvement over such arrangements by providing an integrated apparatus that provides both prime/spray mode control and adjustable pressure setting operation for an electrical pressure control in the spray mode. 
       BRIEF SUMMARY OF THE INVENTION 
       [0003]    The present invention may be seen to be a combined prime valve and electrical pressure control apparatus for paint spray pumps including an inlet port and an outlet port and a return port for the paint spray pump, a prime valve, and a pressure control, with the prime valve and pressure control each contained within a single control housing and each coupled to a single shaft for selectively actuating the prime valve to one of a prime mode and a spray mode, wherein the valve in the prime mode fluidly couples the inlet port to the return port and wherein the valve in the spray mode couples the inlet port to the outlet port and wherein the pressure control is operable within a pressure setting range to control the operation and output pressure delivered by the pump using an electrical control adjustable by movement of the shaft while the valve remains in the spray mode. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  is a perspective view of a paint sprayer pump assembly useful in the practice of the present invention. 
           [0005]      FIG. 2  is an enlarged fragmentary side section view of the paint sprayer pump assembly taken along line II-II of  FIG. 1 . 
           [0006]      FIG. 3  is a front elevation view of a combined prime valve and electrical pressure control apparatus of the present invention shown in a priming mode. 
           [0007]      FIG. 4  is a view similar to that of  FIG. 3 , except shown in a spray mode with a low pressure setting. 
           [0008]      FIG. 5  is a view similar to that of  FIG. 3  in the spray mode, except shown at a high pressure setting. 
           [0009]      FIG. 6  is a perspective view of the apparatus of the present invention shown from above and to the right. 
           [0010]      FIG. 7  is a perspective view of the apparatus of the present invention shown from above and to the left. 
           [0011]      FIG. 8  is a plan view of a pressure setting cam useful in the practice of the present invention. 
           [0012]      FIG. 9  is a perspective view of an electric motor and pump assembly useful in the practice of the present invention. 
           [0013]      FIG. 10  is a front elevation view of the motor and pump assembly of  FIG. 9 . 
           [0014]      FIG. 11  is an exploded view of parts from  FIG. 10 . 
           [0015]      FIG. 12  is a front plan view similar to that of  FIG. 8  of the cam assembly of  FIGS. 10 and 11 . 
           [0016]      FIG. 13  is a rear plan view of the cam assembly of  FIG. 12 . 
           [0017]      FIG. 14  is a side elevation view of the cam assembly of  FIG. 12 . 
           [0018]      FIG. 15  is a perspective view from the front of the cam assembly of  FIG. 12 . 
           [0019]      FIG. 16  is a perspective view from the rear of the cam assembly of  FIG. 12 . 
           [0020]      FIG. 17  is a perspective view from the front of a control housing useful in the practice of the present invention. 
           [0021]      FIG. 18  is a perspective view from the rear of the control housing of  FIG. 17 . 
           [0022]      FIG. 19  is a rear elevation view of the control housing of  FIG. 17 . 
           [0023]      FIG. 20  is a side elevation view of the control housing of  FIG. 17 . 
           [0024]      FIG. 21  is a bottom plan view of the control housing of  FIG. 17 . 
           [0025]      FIG. 22  is a front elevation view of the control housing of  FIG. 17 . 
           [0026]      FIG. 23  is a first section view taken along line XXIII-XXIII of  FIG. 22 . 
           [0027]      FIG. 24  is a second section view taken along line XXIV-XXIV of  FIG. 22 . 
           [0028]      FIG. 25  is a side view of a pressure transducer assembly useful in the practice of the present invention. 
           [0029]      FIG. 26  is a section view taken along line XXVI-XXVI of  FIG. 25 . 
           [0030]      FIG. 27  is a perspective view of a lever useful in the practice of the present invention. 
           [0031]      FIG. 28  is a first side elevation view of the lever of  FIG. 27 . 
           [0032]      FIG. 29  is an end elevation view of the lever of  FIG. 27 . 
           [0033]      FIG. 30  is a second side elevation view of the lever of  FIG. 27 . 
           [0034]      FIG. 31  is a section view taken along line XXXI-XXXI of  FIG. 30 . 
           [0035]      FIG. 32  is a first side elevation view of a pressure switch assembly useful in the practice of the present invention. 
           [0036]      FIG. 33  is an end elevation view of the pressure switch assembly of  FIG. 32 . 
           [0037]      FIG. 34  is a second side elevation view of the pressure switch assembly of  FIG. 32 . 
           [0038]      FIG. 35  is a bottom plan view of the pressure switch assembly of  FIG. 32 . 
           [0039]      FIG. 36  is a view similar to that of  FIG. 10 , except with parts shown in a first position during assembly, and with a portion of the lever cutaway to illustrate certain details of the present invention. 
           [0040]      FIG. 37  is a view similar to that of  FIG. 36 , except with parts shown in a second position during assembly. 
           [0041]      FIG. 38  is a view similar to that of  FIG. 37 , except with parts shown in a third position during assembly. 
           [0042]      FIG. 39  is an enlarged view of detail XXXIX of  FIG. 36  except further cut away and with a C-ring omitted and showing parts in an initial position during an installation process for attachment of the lever to the prime valve in the practice present invention. 
           [0043]      FIG. 40  is an enlarged detail view of detail XIL of  FIG. 37  except further cut away and showing parts advanced to a second position from that shown in  FIG. 39 . 
       
    
    
     DETAILED DESCRIPTION 
       [0044]    Referring now to the Figures, and most particularly to  FIGS. 1 and 2 , a paint spray pump assembly  2  useful in the practice of the present invention may be seen. It is to be understood that assembly  2  is designed and intended to be used to supply paint or similar coating material under pressure to a hand-held paint spray gun (not shown) via a hose (not shown) connected to a paint pump outlet  4 . A paint hopper  6  provides paint to the pump  8 . A knob  9  is provided to operate the combined prime valve and pressure control  10  of the present invention. 
         [0045]    Referring now also to  FIG. 3 , a front elevation view of the prime valve and pressure control apparatus  10  of the present invention may be seen. The apparatus has a single control housing  12  for both the prime valve  14  and the pressure control  16 . A first cam  18  is shown in a first position  20  corresponding to a priming mode. In this position, cam  18  pushes a single prime control pin  22  that urges a lever  24  to pull a poppet (not shown) off a seat (not shown) to provide a priming mode for the paint pump  8  to which apparatus  10  is fluidly connected. In position  20 , a second cam  26  is in a first position  28 , corresponding to a low pressure setting. The single prime control pin or prime valve actuator  22  is oriented with and free to move along a prime valve actuator axis  23 . Cam  18  is movable about an axis  53  of a single shaft  54  on which cam  18  is mounted. 
         [0046]    Referring now to  FIG. 4 , first cam  18  is in a second position  30 , corresponding to a spraying mode in which the priming mode is deactivated. It may be noted that a radius  32  of cam  18  at the pin  22  in the second position  30  is less than a radius  34  of cam  18  at pin  22  in the first position  20  ( FIG. 3 ). This allows the poppet of the prime/spray valve to return to contact with its mating seat to shift from a priming mode to a spraying mode. 
         [0047]    Second cam  26  is shown in a second position  36  in  FIG. 4  in which a pressure control pin  38  urges a switch carrier  40  to move to a low pressure position  42 . It is to be understood that the pressure control pin or electrical pressure control actuator  38  is oriented with and movable along an electrical pressure control actuator axis  39 . It is also to be understood that the second position  36  is preferably only slightly elevated above the pressure level of the first position  28  of cam  26 , indicated by the slightly increased radius  44  of cam  26  at pin  38  in this position, compared to the radius  46  of cam  26  at pin  38  when cam  26  is in the first position  28 . Each of the axes  23  and  39  are oriented generally diametrically opposite one another, and perpendicular to axis  53 . As will be seen infra, the axes  23  and  39  are offset along axis  53  from each other, to align with cams  18  and  26 , respectively. 
         [0048]    Referring now to  FIG. 5 , first cam  18  moves to a third position  48  in which cam  18  has a radius  50  substantially equal to radius  32 , keeping the prime/spray valve  14  in the spray mode. In  FIG. 5 , cam  26  has an increased radius  52  aligned with pin  38  as compared to the operating radius  46  of  FIG. 4  for the low pressure spraying mode. The increased radius  52  sets the switch carrier  40  to a third or high pressure position  51  (for both the pressure control  16  and the second cam  26 ). 
         [0049]    It is to be understood that the knob  9  is preferably received over a shaft  54  to operate apparatus or assembly  10 . Shaft  54  is rotatable to a selected one of the first position  20 ,  28 , the second position  30 ,  36  and the third position  48 ,  51 , as desired, by an operator, to achieve a selected one of the priming, low pressure spraying and high pressure spraying modes. 
         [0050]    Referring now to  FIG. 8 , an outline view of the second cam  26  may be seen. In this embodiment, cam  26  may have indentations or detents  56 ,  58  and  60  aligned respectively with the first position  28 , the second position  36  and the third position  51 , to assist the operator in positioning knob  9  to the desired mode of operation, and to retain the apparatus in the selected desired mode at one of the first, second and third positions  28 ,  36 , and  51 , corresponding to the priming mode, low pressure spraying mode, and high pressure spraying mode. 
         [0051]    Referring now to  FIGS. 9-16 , various views of an alternative embodiment of the present invention may be seen. In this embodiment, slight alterations may be seen in the cam assembly containing cams  18 ′ and  26 .′ A pump inlet  72  receives paint from the paint hopper  6 . The pump  8  delivers paint to the outlet  4  during spraying. When the apparatus  10  is in the priming mode, a valve is opened between the pump inlet  72  and the return line  74 , with the valve actuator  76  moving to the left, as shown in  FIG. 3 . 
         [0052]    In  FIG. 10  the prime valve and pressure control apparatus  10  is shown in the first position  20  (the prime mode) corresponding to that shown in  FIG. 3 . 
         [0053]      FIG. 11  shows an exploded view of the apparatus  10 , with a lever  62  on one side of the control housing  12 ′ and a pressure transducer assembly  64  and a pressure switch assembly  66  on the other side of the housing  12 .′ Each of the lever  62  and the pressure switch assembly  66  are retained to a base housing  13  (to which the control housing  12 ′ is attached) by respective pivot pins  68 ,  70 , when parts are assembled. In  FIG. 11 , a “C” ring  78  is shown in the exploded view and also shown rotated 90 degrees in view  80  to illustrate the topology of ring  78 . Ring  78  is used to retain a washer  82  on the valve actuator shaft  76  when received in a groove  84  sized to receive ring  78 , in a manner to be described infra. 
         [0054]    Pressure control pin  38  may have a hat or cap  86 , which may be formed of nylon 6/6, to provide a low friction sliding contact with the pressure switch assembly  66 . Assembly  66  is held against the pressure transducer assembly  64  by a spring  88 . 
         [0055]    Referring now to  FIGS. 12-16 , various views of a cam assembly  90  useful in the practice of the present invention may be seen. Cam assembly  90  includes first cam  18  and second cam  26  mounted for rotation by shaft  54 . A plurality of apertures  92  may be provided in cam assembly  90  for engagement with a projection  94  on knob  9  (as may be seen in  FIG. 2 ). Reception of projection  94  in a particular one of apertures  92  provides positive, repeatable engagement between knob  9  and cam assembly  90 . Cam assembly  90  may be formed by insert molding cams  18  and  26  to shaft  54 . 
         [0056]    Referring now to  FIGS. 17-24 , various views of control housing  12 ′ may be seen. It is to be understood that this embodiment differs from that shown in  FIGS. 3-5  in that the control housing  12  includes fluid ports, while control housing  12 ′ is a separate housing for the cam assembly  90  and does not itself include fluid ports, but rather is connected to a pump housing having the fluid ports and certain operating components contained therein. More particularly, control housing  12  includes the outlet port  4  and the prime/spray valve (connected to valve actuator  76 ) and pressure transducer assembly  64 . The control housing  12 ′ (together with base housing  13 ) may be secured to or form part of a pump housing by a conventional threaded fastener secured through aperture  96 . Control housing  12 ′ straddles the outlet port  4  with a pair of legs  98 . A cam chamber  100  provides a generally cylindrical recess  102  for the cam assembly  90 . A centrally located bore  104  provides a bearing surface for a rear extension  106  of shaft  54 . A first radially extending bore  108  supports the prime control pin  22  and a second radially extending bore  110  supports the pressure control pin  38 . Bores  108  and  110  are preferably axially offset, as may be clearly seen in  FIG. 24 , to align pins  22  and  38  with the first and second cams  18 ,  26 , respectively, when cam assembly  90  is received in the cam chamber  100 . 
         [0057]    Referring now most particularly to  FIGS. 21 and 24 , there is an offset  111  between axes  23  and  39 . Offset  111  is aligned with axis  53  of shaft  54  to provide alignment of pin  22  with cam  18  and alignment of pin  38  with cam  26 . 
         [0058]    Referring now most particularly to  FIGS. 25 and 26 , a side and section view of the pressure transducer assembly  64  may be seen. Assembly  64  includes an outer housing  112  having external threads  114  to secure the assembly in the pump housing. One or more hexagonal bosses  116  are provided with conventional wrench flats  118  to enable installation and removal of the assembly  64 . A piston  120  is received in housing  112  and sealed thereagainst by an O-ring  122 . Piston  120  has a flange  124  against which a compression spring  126  reacts with respect to the housing  112 . A face O-ring  128  seals the outer housing  112  against the pump housing to which it is attached. It is to be understood that an inner face  130  of piston  120  is exposed to the pressure of the paint at the outlet  4  of the pump  8  when the assembly  64  is installed in the pump housing and the pump is operating. In operation, a stem  132  extends out of housing  112  by a distance proportional to the pressure on face  130 . Stem  132  will act on the pressure switch assembly  66  in a manner described infra. 
         [0059]    Turning now to  FIGS. 27-31 , various views of lever  62  may be seen. Lever  61  is pivotably attached to one of the control housing  12  (as shown in  FIG. 6 ) or to the base housing  13  or the pump housing (as shown by  FIG. 11 ). Lever  62  has a clevis  134  formed by a pair of ring like projections  136 , spaced apart from each other and each of which have an aperture  140  to receive the pivot or clevis pin  68  to pivotably secure the lever  62  to a similar apertured ring  138  (see  FIG. 11 ) on the part to which the lever is attached. Lever  62  also has a distal projection  142  to receive the force of the prime control pin  22 . A groove  144  may be formed in projection  142  to matingly receive a correspondingly rounded end on pin  22 . A recess  146  is formed in the body  148  of the lever  62 . An arcuate bearing surface  150  having a radius  152  is formed in the body  148  adjacent the recess  146 . Surface  150  preferably has an elongated slot  154  formed therein to receive the valve actuator stem  76 . When the parts are assembled, surface  150  is in contact with washer  82 . 
         [0060]    Referring now most particularly to  FIGS. 32-35 , various views of the pressure switch assembly  66  may be seen. Assembly  66  includes a conventional switch  160  of the type manufactured under the trademark Microswitch by Honeywell. Switch  160  has an operator  162  covered by a lever  164 , and terminals  166 ,  168  for electrical connection. Switch  160  may be mounted to the switch carrier  40  by a pair of posts  170  with push-on retaining fasteners  172 . Carrier  40  may have a first extension  174  with a bore  176  for pivotably mounting the assembly  66  to the base housing  13  using pivot pin  70  (shown in  FIG. 11 ). Carrier  40  may also have a second extension  178  with a set screw  180  installed therein to serve as a bearing surface for pressure control pin  38 . As may be seen by reference to  FIGS. 7 and 11 , the spring  88 , connected between a screw  186  in switch carrier  40  and a boss  188  on the pressure transducer assembly  64  preferably urges assembly  66  towards the pressure transducer assembly  64  mounted to base housing  13 , while the pressure control pin  38  positions the assembly  66  at a desired distance (corresponding to the desired pressure) from the pressure transducer assembly  64 . 
         [0061]    Referring now to  FIGS. 36-40  certain aspects of a process of assembly of the prime valve and pressure control apparatus of the present invention may be seen. In  FIGS. 36 and 39 , parts are shown in a first position during assembly, with a portion of the lever  24  cutaway. To assemble the prime valve parts, the cam assembly  90  is rotated to an “install” position  190  shown in  FIG. 36 , and the washer  82  is assembled on the valve actuator shaft  76 , as may be seen most clearly in  FIG. 39 , after which the C ring  78  is placed in groove  84  on the shaft  76 , retaining the washer  82  and lever  24  to the valve actuator  76 . Next, the cam assembly  90  is rotated about  240  degrees counterclockwise to a position  192  shown in  FIG. 37 , moving the lever  24  away from base housing  13  and causing the ring  78  to become tight against a wedge-shaped recess  188  in washer  82 , as may be seen most clearly in  FIG. 40 . 
         [0062]    After the assembly process associated with the prime valve is complete (as described above), the pressure control apparatus may be assembled. The pressure control pin  38  is inserted in bore  110  in the housing  12  (or  12 ′), cap  86  is placed on pin  38 , and the pressure switch assembly  66  is pivotably attached to the base housing  13  using pivot pin  70 . Spring  88  is then installed between the pressure switch assembly  66  and the base housing  13 , to urge the switch carrier  40  and switch  160  towards and against the stem  162  of the pressure transducer assembly  64 . It may be noted that once pin  38  is installed, the cam assembly  90  cannot thereafter be rotated from position  192  back to the install position  190 , because of interference between pin  38  and an end-of-travel tab  194  on the second cam  26 . Setscrew  180  maybe adjusted in switch carrier  40  by advancing or retracting setscrew  180  in a threading motion with respect to the carrier  40  to calibrate the set point of switch  160  as activated by stem  162  at a desired maximum pressure setting. The maximum pressure setting position  196  is obtained by rotating the cam assembly  90  to the maximum pressure setting position  196  of cam  26 . The pump  8  is turned on, and the pressure monitored while the setscrew  180  is screwed into or out of the carrier  40  until the desired pressure setting is reached and the pump is turned off by switch  160  at that pressure.