Piston pump having housing with a pump housing and a pump assembly drive housing formed therein

Information

  • Patent Grant
  • 6599107
  • Patent Number
    6,599,107
  • Date Filed
    Thursday, May 30, 2002
    22 years ago
  • Date Issued
    Tuesday, July 29, 2003
    21 years ago
Abstract
A fluid pump for pumping a volume of fluid under pressure from a fluid source to a fluid dispenser includes an electric motor. A pump drive assembly is operably coupled to the motor for reducing an output of the motor. A pump assembly is operably coupled to the pump drive assembly and is fluidly communicable with the source of fluid, the pump assembly being actuated by the pump drive assembly, the actuation causing the pump assembly to pump the fluid. A single main housing, the main housing in part the pump drive assembly and having a pump housing defined therein, the pump housing being integral, unitary therewith for housing the pump assembly. A method of making a fluid pump for pumping a volume of fluid under pressure from a fluid source to a fluid dispenser.
Description




TECHNICAL FIELD




The present invention relates to a pump. More particularly, the present invention relates to a liquid pump useful for pumping liquid paints, stains, and the like.




BACKGROUND OF THE INVENTION




There is a need for inexpensive yet reliable and effective pumps for pumping fluids, including paint, stains, and the like to a dispenser of such fluids. Such pumps are primarily intended for use in a household environment, as distinct from a commercial environment. Accordingly, the emphasis is on cost containment, while having the requisite durability for the environment of the intended use. The pump's pressure should be readily adjustable for use with very high flow rates and high pressures and for use with relatively low flow rates and low pressures. An example of high flow rates and high pressures would be the use of a spray gun dispenser with relatively high viscosity paint. Dispensing a relatively low viscosity stain through a spray gun typically requires significantly lower pressures, but the flow rate is high. A further type of dispensation is by means of a roller that is supplied with paint from the pump. Such means of dispensation require a relatively low fluid volume at relatively low fluid pressure for delivery of the viscous paint. There is a need in the industry for a pump that has adjustable pressure settings to accommodate all the exemplary types of dispensation listed above and other types of dispensation as well.




There is a further need in the industry to enhance the reparability of such pumps. A potential problem area with such pumps is the pump assembly. If there is difficulty with the pump assembly, it is desirable that the pump assembly be readily removable from the housing in which it is disposed for repair or replacement. In existing pumps, the pump assembly is not readily removable.




There is a further need to simplify as much as possible the construction of the pump. A reduction in the number of component parts is one path to such simplification. One area in which such simplification is desirable is in the area of the pressure switch assembly. In the past, such assemblies were complex and required rather lengthy plumbing between the pump assembly and the position on the side of the motor housing where the pressure switch assembly was mounted. Another area of needed simplification is that, in the existing pumps, the main gear housing and the pump assembly housing are formed as two separate components. A desired simplification of the structure of the pump would be to combine the main gear housing and the pump housing into a single component. A further area of needed simplification is in the number of cast components as distinct from more costly screw machined parts.




SUMMARY OF THE INVENTION




The present invention substantially meets the aforementioned needs of the industry. Simplification of the piston pump of the present invention is evident in a single main housing that incorporates a housing for both the pump assembly and the pump drive assembly. Additionally, the pump housing is machinable from a single direction to simplify production. A further benefit of this is that it allows the pump assembly installed in the pump housing to be fully serviceable from that same direction.




Additionally, the pressure switch assembly of the present invention is greatly simplified in construction with respect to the pressure switch assemblies of the prior art. And, the pressure switch assembly of the present invention allows for greatly varying flow pressure of the liquid pumped by the piston pump of the present invention, unlike pressure switch assemblies of the prior art. The pressure switch assembly advantageously has a certain compliance built in to accommodate an over pressure condition without damage to any pressure switch assembly components.




Another area of simplicity in the design of the piston pump of the present invention is in the design of the pump assembly. The pump assembly is elongate in design and is readily extractable from the pump housing bore for repair as necessary. Further, a number of key components are now cast, where previous components performing the same function were screw machined, a significantly more costly operation.




The present invention is a fluid pump for pumping a volume of fluid under pressure from a fluid source to a fluid dispenser includes an electric motor. A pump drive assembly is operably coupled to the motor for reducing an output of the motor. A pump assembly is operably coupled to the pump drive assembly and is fluidly communicable with the source of fluid, the pump assembly being actuated by the pump drive assembly, the actuation causing the pump assembly to pump the fluid. A main housing, the main housing containing in part the pump drive assembly and having a pump housing defined therein, the pump housing being integral, unitary therewith for housing the pump assembly. The present invention is further method of making a fluid pump for pumping a volume of fluid under pressure from a fluid source to a fluid dispenser.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a perspective left side view of the piston pump of the present invention;





FIG. 1



a


is a perspective right side view of the piston pump of the present invention;





FIG. 2

is a left side sectional view of the piston pump;





FIG. 3

is a front sectional view of the pump assembly of the piston pump; and





FIG. 4

is a sectional perspective view of the pressure switch of the piston pump.











DETAILED DESCRIPTION OF THE DRAWINGS




The piston pump of the present invention is shown generally at


10


in the figures. Referring to

FIG. 2

, the piston pump


10


has four major components: pump drive assembly


12


, pump assembly


14


, pressure switch assembly


16


, and electric motor


18


.




The pump drive assembly


12


of the piston pump


10


has two major subcomponents: main housing


20


and gear housing


22


.




The main housing


20


is preferably a single casting that functions to house, in part, the gear train of the piston pump


10


and also functions as the pump housing of the piston pump


10


. The main housing


20


has a plurality of threaded bores


24


defined therein. The main housing


20


further includes an eccentric gear bearing housing


26


and a spaced apart reduction gear bearing housing


28


. The main housing


20


defines an interior cavity in cooperation with the gear housing


22


, the interior cavity functioning as the gear box


30


.




The main housing


20


further includes the pump housing


32


. The pump housing


32


is comprised of a pump housing bore


34


. Referring to

FIG. 4

, the main housing


20


additionally includes a pressure switch bore


36


defined therein.




The gear housing


22


has a plurality of screw bores


38


, as depicted in FIG.


2


. When the main housing


20


and gear housing


22


are assembled, the threaded bores


24


of the main housing


20


and the screw bores


38


of the gear housing


22


are in registry. Suitable threaded fasteners (not shown) may be inserted through the screw bores


38


and threaded into the threaded bores


24


to secure the main housing


20


to the gear housing


22


. The gear housing


22


includes an eccentric gear bearing housing


40


and a shaft bearing housing


42


. A shaft bore


44


is formed coaxial with the shaft bearing housing


42


. A reduction gear bearing housing


46


is also defined in the gear housing


22


.




The electric motor


18


of the piston pump


10


has an output shaft


48


that is supported in a bearing


47


disposed in the shaft bearing housing


42


. The output shaft


48


terminates in a spline


50


that projects through the shaft bore


44


defined in the gear housing


22


.




The pump drive assembly


12


of the piston pump


10


includes three major subcomponents: reduction gear


52


, drive gear assembly


54


, and yoke assembly


56


.




The reduction gear


52


has opposed ends


57




a


,


57




b


. The ends


57




a


,


57




b


are respectively rotatably borne in an end bearing


58


disposed in the reduction gear bearing housing


46


and in an end bearing


58


disposed in the reduction gear bearing housing


28


of the main housing


20


. The reduction gear


52


has a first gear


60


and a second gear


62


. The first gear


60


has a substantially greater diameter than the second gear


62


and has a significantly greater number of teeth. Accordingly, while the rotational speed of the first gear


60


and the second gear


62


are the same, the speed taken tangential to the second gear


62


is substantially reduced with respect to the speed taken tangential to the first gear


60


. The first gear


60


is rotationally engaged with the spline


50


of the electric motor


18


. The second gear


62


is rotationally engaged with the drive gear assembly


54


.




The drive gear assembly


54


has a first end shaft


64


that is rotationally borne by a needle bearing


66


disposed in the eccentric bearing housing


40


defined in the gear housing


22


. A thrust bearing


68


is disposed concentric with the first end shaft


64


between a face of the drive gear assembly


54


and a face of the gear housing


22


. The second end shaft


69


of the drive gear assembly


54


is rotationally borne in a bearing


70


disposed within the eccentric gear bearing housing


26


defined in the main housing


20


. The relatively large gear


72


of the drive gear assembly


54


is meshed with the relatively small second gear


62


of the reduction gear


52


. The reduction gear


52


and the drive gear assembly


54


cooperate to reduce the output of the electric motor


18


at a preferred ratio of approximately 34:1. Accordingly, the electric motor


18


operating at approximately 12,000 rpm is reduced to approximately 260 rpm at the drive gear assembly


54


and 260 strokes per minute at the pump assembly


14


. The output of the drive gear assembly


54


is eccentric output shaft


74


. The center line


73


of the eccentric output shaft


74


is offset from the center of rotation


75


of the drive gear assembly


54


, such that rotation imparted to the drive gear assembly


54


via the gear


72


produces an orbital rotation of the eccentric output shaft


74


. Accordingly, the eccentric output shaft


74


has both rotational motion and orbital motion (see also FIG.


3


).




The orbital motion of the eccentric output shaft


74


is imparted to the yoke assembly


56


. The rotational motion of the eccentric output shaft


74


is not imparted to the yoke assembly


56


since the eccentric output shaft


74


rotates with respect to the yoke assembly


56


.




As depicted in

FIGS. 2 and 3

, the yoke assembly


56


has a yoke


79


with a bearing housing


76


defined therein. A bearing


77


is disposed within the bearing housing


76


. The bearing


77


rotationally supports the eccentric output shaft


74


. During operation, the eccentric output shaft


74


rotates with respect to the bearing


77


. The bearing


77


is fixed within the bearing housing


76


.




A pair of spaced apart yoke arms


78


depend from the yoke assembly


56


. The yoke arms


78


define a yoke aperture


80


between the two yoke arms


78


. A pair of opposed pin bores


81


are defined in the yoke arms


78


. The outside pin bore


81


carries fully through the yoke arm


78


. A dowel pin


82


is disposed in the pin bores


81


. The dowel pin


82


operably couples the piston assembly


84


to the yoke assembly


56


. In a preferred embodiment, the yoke of the yoke assembly


56


is formed of a zinc alloy casting. Preferably, the lubricity of the zinc alloy is sufficient to carry the steel dowel pin directly without the need for dowel pin bushings. Such lubricity is sufficient to provide for negligible wear at the rotational intersection of the dowel pin


82


with the pin bores


81


.




The second component of the piston pump


10


is the pump assembly


14


, depicted in

FIGS. 2 and 3

. It is significant to note that the pump assembly


14


is disposed in the pump housing


32


formed integrally with the main housing


20


. In a preferred embodiment, the main housing


20


is cast of aluminum containing material. Accordingly, the pump housing bore


34


of the main housing


20


is also formed of aluminum. In the past, the pump housing of a prior art pump has always been made separate from the main housing


20


. Typically, the pump housing has been made of steel that has been screw machined and is then affixed in the main housing, typically by a threaded engagement or being pressed in. By forming the pump housing


32


integral with the main housing


20


considerable cost savings are achieved. Further, casting the entire main housing


20


, including the pump housing


32


, out of aluminum has resulted in further cost savings for the piston pump


10


of the present invention.




The pump assembly


14


of the piston pump


10


has three primary subcomponents: piston assembly


84


(see FIGS.


2


and


3


), prime assembly


86


(see FIG.


3


), and outlet


88


(see FIG.


3


).




The piston assembly


84


is an elongate rod preferably made of steel. In a preferred embodiment, the steel piston


90


is slidably, translatably disposed within the aluminum pump housing bore


34


of the pump housing


32


. In order to prevent galling of the pump housing bore


34


, there is a small circumferential space defined between the exterior surface of the piston


90


and the interior surface of the pump housing bore


34


. This slight space makes it possible to translate the steel piston


90


within the aluminum pump housing bore


34


without inducing appreciable wear of the pump housing bore


34


.




A transverse pin bore


92


is defined in the piston


90


proximate the upper margin of the piston


90


. The dowel pin


82


is disposed in the pin bore


92


in order to couple the piston


90


of the yoke assembly


56


. As the yoke assembly


56


rotates through its orbital motion, the piston


90


rocks back and forth about the dowel pin


82


in order to maintain the desired concentric alignment of the piston


90


with respect to the pump housing bore


34


.




An upper fluid chamber


94


is defined in part internal to the piston


90


and in part external to the piston


90


. Accordingly, the fluid chamber


94


is defined by the volume of the fluid chamber


94




a


plus the volume of the fluid chamber


94




b


. The fluid chamber


94




a


is defined by a longitudinal bore defined within the lower portion of the piston


90


. The fluid chamber


94




b


is defined between the exterior surface of the piston


90


and the interior surface of the pump housing bore


34


. The fluid chambers


94




a


,


94




b


are fluidly coupled by a fluid passage


95


defined in the piston


90


transverse to the longitudinal axis of the fluid chamber


94




a.






Referring to

FIG. 3

, a prime passage


98


is fluidly coupled to the fluid chamber


94


. An outlet passage


100


is also fluidly connected to the fluid chamber


94


. In a preferred embodiment, a pressure switch passage


96


intersects the outlet passage


100


. As will be seen, the pressure switch passage


96


could intersect either the prime passage


98


or the outlet passage


100


and still provide an adequate pressure reading to the pressure switch assembly


16


, discussed in detail below.




An upper ball


102


(see

FIGS. 2 and 3

) or outlet valve defines the lower margin of the volume of the fluid chamber


94


. The upper ball


102


is retained within an upper ball cage


104


. The upper ball cage


104


has a plurality of cage bores


105


defined therein such that, when the upper ball


102


is pressed upward against the upper ball cage


104


, fluid is free to pass around the upper ball


102


and through the cage bores


105


into the fluid chamber


94


. An upper seat


106


is disposed beneath the upper ball


102


. The upper seat


106


is generally ring shaped having a bore


108


defined centrally thereto. The upper seat


106


is retained in position in engagement with the upper ball cage


104


by a retainer


110


. The retainer


110


is preferably threaded into the piston


90


. Retainer


110


has a centrally defined axial retainer bore


112


.




The piston


90


is translatably disposed within an upper seal bushing


114


. The upper seal bushing


114


is retained within the pump housing bore


34


by a retaining clip


115


. A circumferential upper seal


116


is disposed at the lower margin of the upper seal bushing


114


.




A cylinder fitting


118


is disposed in the lower portion of the pump housing bore


34


for supporting the piston


90


in the manner of a bushing. An O-ring


120


is preferably disposed in a groove defined in a cylinder fitting


118


proximate the upper margin of the cylinder fitting


118


. The cylinder fitting


118


further holds a lower seal


122


in sealing engagement with the piston


90


. The cylinder fitting


118


is held in threaded engagement with the pump housing bore


34


by threads


124


.




A lower fluid chamber


125


is defined within the cylinder fitting


118


. The pump assembly


14


is a double acting pump. The volume of the fluid chamber


94


is approximately one-half the volume of the lower fluid chamber


125


. Fluid is discharged from the fluid chamber


94


on both the downstroke of the piston


90


and on the upstroke of the piston


90


. The lower fluid chamber


125


is filled only on the upstroke of the piston


90


. Accordingly, there is no discernable lapse in fluid discharge from the pump assembly


14


, even though the chamber


125


is filled only on the upstroke of the piston


90


.




The lower margin of the lower fluid chamber


125


is defined by the lower ball


128


or the inlet valve. The lower ball


128


is retained within a lower ball cage


130


. A plurality of ball cage bores


132


are defined in the lower ball cage


130


, such that when the lower ball


128


is pressed upward against the lower ball cage


130


, fluid is free to pass upward around the lower ball


128


through the ball cage bores


132


into the lower fluid chamber


125


. A seat


134


is disposed beneath the ball cage


130


. The seat


134


is generally ring shaped having a centrally defined bore


136


. In a preferred embodiment, the lower ball cage


130


may be cast integrally, unitary with the cylinder fitting


118


to eliminate the need for retaining components necessary for a ball cage that is formed separate from the cylinder fitting


118


. This design contributes to the simplification of the piston pump


10


. An inlet fitting


142


having a centrally defined inlet passage


144


may be threaded into the cylinder fitting


118


.




In a preferred embodiment, both the upper seal bushing


114


and the cylinder fitting


118


are formed of a zinc alloy. By making the upper sealing bushing


114


and the cylinder fitting


118


of the zinc alloy, the two components can be cast. This is a significant departure from prior practice in which components performing the function of the upper seal bushing


114


and the cylinder fitting


118


were made of screw machined bronze. As compared to a cast zinc fitting, screw machined fittings are significantly more expensive.




A further advantage of the design of the piston pump


10


of the present invention is that the entire fluid section comprising the pump assembly


14


is what may be termed a “bottom up” design. By this is meant that the pump housing bore


34


, by having ever decreasing bore diameters from the bottom to the top as depicted in

FIGS. 2 and 3

, may be machined in its entirety from the bottom up. Further, servicing of the pump assembly


14


is greatly enhanced by this design. Merely withdrawing the dowel pin


82


and removing the retaining clip


115


allows the entire pump assembly


14


to be withdrawn from the bottom of the piston pump


10


for servicing of the pump assembly


14


. The same feature that provides for the enhanced servicing of the pump assembly


14


also provides for ease of assembly of the pump assembly


14


into the main housing


20


. A fully assembled pump assembly


14


may be simply inserted from the bottom upward into the pump housing bore


34


and then coupled to the yoke assembly


56


by means of the dowel pin


82


and secured within the pump housing bore


34


by means of the retaining clip


115


. In the past, some assembly of the components performing the function of the pump assembly


14


was done from above and some done from below, greatly increasing the complexity of assembly and maintenance of the piston pump


10


.




The second component of the pump assembly


14


of the piston pump


10


is the prime assembly


86


. The prime assembly


86


is best depicted in FIG.


3


. The prime assembly


86


includes a ball/stem assembly


150


. The ball/stem assembly


150


is translatably disposed within a prime bore


152


defined in the main housing


20


. In a preferred embodiment, the prime bore


152


is oriented transverse to and offset from the longitudinal axis of the pump housing bore


34


. An O-ring


154


resides in a groove defined in the exterior surface of the ball/stem assembly


150


to create a substantially fluid tight seal between the ball/stem assembly


150


and the prime bore


152


.




A ball


156


is disposed at a proximal end of the ball/stem assembly


150


. The ball


156


engages a seat


160


. The seat


160


is generally ring shaped having a central passage


162


defined therein. The central passage


162


is in fluid communication with the prime passage


98


. A spring


166


is disposed concentric with the ball/stem assembly


150


. The spring


166


acts to bias the ball/stem assembly


150


in a leftward direction as depicted in FIG.


3


. Such bias acts to seat the ball


156


on the seat assembly


158


. The spring


166


bears on a shoulder of the ball/stem assembly


150


and a lock washer


168


. A nut


170


holds the lock washer


168


in place. A cam


172


is interposed between the nut


170


and the knob


174


. Finally, a nut


176


on the distal end of the ball/stem assembly


150


holds the knob


174


in place. The knob


174


is manually rotatable between a “spray” position and a “prime” position. See FIG.


1


.




The final component of the pump assembly is the outlet


88


, as depicted in FIG.


3


. The outlet


88


includes a spray hose fitting


180


. The spray hose fitting


180


is meant to interface between a hose coupled to a dispenser, such as a spray gun, and the piston pump


10


of the present invention. The spray hose fitting


180


is fluidly coupled to the outlet


88


.




The pressure switch assembly


16


of the piston pump


10


of the present invention has three major subcomponents: pressure sensor assembly


182


, micro switch assembly


184


, and set screw assembly


186


.




The pressure sensor assembly


182


is in fluid communication with the pressure switch passage


96


(depicted in

FIGS. 3 and 4

) and thereby is in fluid communication with the fluid chamber


94


. Referring to

FIG. 4

for the rest of this description, the pressure sensor assembly


182


is disposed in the pressure switch bore


32


defined in the main housing


20


. A spring retainer housing


189


is threadedly engaged in the bore


188


. The spring retainer housing


189


has an end wall


190


. The end wall


190


has a plunger aperture


191


centrally defined therein. The spring retainer housing


189


bears on a bushing


192


. The bushing


192


has a bushing bore


194


defined therein. Bushing


192


is a circular groove defined in an end margin thereof with an O-ring


196


disposed in the groove to define a substantially fluid tight seal between the pressure sensor assembly


182


and the main housing


20


. A plunger


198


is translatably disposed along a longitudinal axis of the spring retainer housing


189


. The proximal end


200


of the plunger


198


is carried within the bore


194


defined in the bushing


192


. In such disposition, the proximal end


200


is exposed to the fluid pressure in the pressure switch passage


96


.




The plunger


198


has a shoulder


202


that abuts a second end margin bushing


192


when no pressure is being sensed by the pressure sensor assembly


182


. The distal end


204


of the plunger


198


projects through the plunger aperture


194


defined in the end wall


190


.




A spring


206


is disposed within the spring retainer housing


189


concentric with the plunger


198


. A first end of the spring


206


bears on the end wall


190


and a second end of the spring


206


bears on the shoulder


202


. The bias of the spring


206


acts to urge the plunger


198


in a rightward (closed) direction, as depicted in FIG.


4


.




The micro switch assembly


184


includes a substantially planar switch body


208


having a generally circular connector


210


. The connector


210


is disposed circumferential to a portion of the spring retainer housing


189


and is fixedly coupled thereto by a set screw


212


.




A pivot arm


214


projects outwardly from the switch body


208


(toward the viewer of FIG.


4


). The micro switch


209


is rotatably disposed on the pivot arm


214


. The pivot arm


214


has a small coil spring


216


disposed thereon. The spring


216


has a first end


218


engaged in a groove defined in the switch body


208


. A second end


220


of the spring


216


engages an edge margin of the housing


222


of the micro switch


209


.




A generally cylindrical actuator connector


221


is formed integral with the switch body


208


generally opposite to the connector


210


. The actuator connector


221


has a threaded bore


219


defined therethrough.




As indicated above, the micro switch


209


has a switch housing


222


. The switch housing


222


has a pivot bore


224


defined therethrough. The micro switch


209


is pivotally borne on the pivot arm


214


by the pivot bore


224


. The bias exerted by the spring


216


tends to rotate the micro switch


184


in a clockwise direction about the pivot arm


214


.




The switch housing


222


has a deflectable metallic paddle


226


disposed on a side margin of the switch housing


222


facing the plunger


198


. The distal end of the paddle


226


rests on a small switch


228


projecting from the side margin of the switch housing


222


. The micro switch


209


is connected by suitable wire connectors (not shown) to the motor


18


.




The set screw assembly


186


of the pressure switch assembly


16


includes a spindle body


230


. The spindle body


230


has a longitudinal bore


232


defined therein. The spindle body


230


further includes a threaded exterior margin


233


that is threaded into the threaded bore


219


of the actuator connector


221


. A dowel pin


234


and a spring


236


are disposed in tandem within the longitudinal bore


232


. The spring


236


acts on a first end of the dowel pin


234


urging a second end of the dowel pin


234


into engagement with the switch housing


222


of the micro switch


184


. The bias of the spring


236


acts to urge the switch housing


222


to pivot in a counterclockwise direction about the pivot arm


214


. Accordingly, the spring


206


and the spring


236


act opposing one another. A set screw


238


is threadedly engaged with an end of the longitudinal bore


232


to retain the spring


236


within the longitudinal bore


232


. An e-clip


240


disposed in a circumferential groove on the dowel pin


234


acts to limit the leftward travel of the dowel pin


234


in the longitudinal bore


232


.




A pressure switch knob


242


is fixedly coupled to the spindle body


230


. In an embodiment, a portion of knob


242


projects through an aperture defined in the pump shroud


244


, as depicted in

FIG. 1



a


, to facilitate manual actuation thereof.




In operation, an operator of the piston pump


10


connects a suction hose to the inlet fitting


142


. A return line is coupled to the return fitting


164


. Typically, the suction line and the return line are routed together such that the open ends of the suction line and the return line are immersed in the fluid in a fluid container. A high pressure hose is connected to the spray hose fitting


180


. A fluid dispenser is typically coupled to a second end of the high pressure hose. As previously indicated there are a number of different types of fluid dispensers. Each of such dispensers offers a certain amount of resistance to the flow of fluid from the spray hose fitting


180


to through the high pressure hose and out the dispenser.




The motor


18


is then activated by on/off switch


246


(

FIG. 1

) and, by means of the pump drive assembly


12


, the pump assembly


14


commences reciprocal (up/down) motion at a preferred rate of about 260 cycles per minute. The operator selects the prime position on the prime assembly


86


by rotation of the knob


174


(

FIG. 1



a


). Rotation of the knob


174


to the prime position causes the knob


174


to ride up on the cam


172


. This motion causes the ball/stem assembly


150


to move to the right, as depicted in

FIG. 3

, thereby unseating the ball


156


. This opens a path of low flow resistance from the pump assembly


114


through the prime passage


98


and out the return fitting


164


. The resistance to flow in this pathway is substantially less than the resistance to flow through the high pressure hose. Accordingly, substantially all of the fluid initially pumped by the pump assembly


14


is returned through the prime assembly


86


to the fluid container via the return fitting


164


.




When the operator discerns that fluid is flowing through the return fitting


164


(typically the return hose is clear plastic and the fluid flow can be visually determined), the operator can be assured that the piston pump


10


is primed. The operator then turns the knob


174


to the spray position. The knob


174


backs off the cam


172


, allowing the ball/stem assembly


150


to translate to the left and seating on the seat


160


. The bias of the spring


166


holds the ball


156


in sealing engagement with the seat


160


, thereby closing off the prime passage


98


. At this point, fluid pressure begins to build in the high pressure hose.




As the pressure builds, the pressure acts on the proximal end


200


of the plunger


198


of the pressure switch assembly


16


. The plunger


198


translates leftward, as depicted in

FIG. 4

, against the bias of spring


206


. At a selected pressure, the distal end


204


of the plunger


198


contacts the paddle


226


of the micro switch


184


. Further pressure on the paddle


226


causes the switch


228


to translate leftward, generating a signal that is sent to the motor


18


to turn the motor


18


off to limit fluid pressure to the desired pressure.




Activation of the fluid dispenser at the end of the high pressure hose causes the discharge of fluid and causes the fluid pressure in the piston pump


10


to drop. In a preferred embodiment, when the pressure has dropped approximately 400 pounds per square inch, the plunger


198


will have translated to the right sufficiently to release pressure on the paddle


226


and on the switch


228


, thereby causing the switch


228


to translate rightward. Such translation sends a further signal to the motor


18


activating the motor


18


to again increase the fluid pressure by operating the pump assembly


14


.




The fluid pressure at which the switch


228


is activated may be adjusted by rotating the pressure switch knob


242


. Rotation of the pressure switch knob


242


either clockwise or counterclockwise causes the spindle body to translate within the actuator connector


221


. Such rotation causes the dowel pin


234


to translate either rightward or leftward as desired, thereby rotating the micro switch


184


as indicated by the arrow A. Translation of the dowel pin


234


to the right, as depicted in

FIG. 4

, places the paddle


226


in closer proximity to the distal end


204


of the plunger


198


. Such disposition will result in the switch


228


being actuated by the plunger


198


at a lower fluid pressure. In a preferred embodiment, rotation of the pressure switch knob


242


of the set screw assembly


186


permits selection of the shutoff pressure as desired between about 0 psi and 3000 psi and more preferably between about 400 psi and 2750 psi.




In the event of an over pressure condition, in which the plunger


198


presses hard enough on the paddle


226


to potentially crush the micro switch


184


, the micro switch


184


may be rotated clockwise without moving the spindle body


230


. There is a certain amount of compliance built into the set screw assembly


186


owing to the tandem arrangement of the dowel pin


234


and the spring


236


. The dowel pin


234


may be translated leftward further compressing the spring


236


responsive to excessive pressure exerted by the plunger


198


. If the dowel pin


234


were not capable of such translation against the spring


236


, an over pressure condition would potentially cause the plunger


198


to crush the micro switch


184


. After relief of the over pressure condition, the plunger


198


translates rightward and the compressed spring


236


acts on the dowel pin


234


to urge the micro switch


184


into counterclockwise rotation to its original disposition prior to the over pressure condition.




Several embodiments of the invention are described herein. These embodiments are illustrative of the invention only and should not be construed as embracing all the embodiments of the present invention or as limiting the scope of the invention.



Claims
  • 1. A fluid pump for pumping a volume of fluid under pressure from a fluid source to a fluid dispenser comprising:an electric motor; a pump drive assembly being operably coupled to the motor for being driven thereby; a pump assembly, operably coupled to the pump drive assembly and being fluidly communicable with the source of fluid, the pump assembly being actuated by the pump drive assembly; a single main housing, the main housing receiving in part the pump drive assembly therein and having a pump housing defined therein and formed integrally with the main housing for housing the pump assembly.
  • 2. The fluid pump of claim 1 wherein a fluid housing is formed in the main housing.
  • 3. The fluid pump of claim 2 wherein the main housing is cast from a metal material containing aluminum.
  • 4. The fluid pump of claim 2 wherein the pump housing includes a pump housing bore, the pump housing bore defining in part a cylinder, a pump assembly piston being translatably disposable in the cylinder, the piston being formed of a ferric material.
  • 5. The fluid pump claim 4 wherein the piston is substantially translatably borne in at least one bushing and is spaced apart from the cylinder to prevent galling of the cylinder during translation of the piston relative to the cylinder.
  • 6. The fluid pump of claim 5 having at least a first bushing disposed in the pump housing bore, the bushing bearing the translational motion of the piston, and a second fluid housing adapted to operate with the fluid housing to provide a double action pump.
  • 7. The fluid pump of claim 2, further comprising a second fluid housing adapted to operate with the fluid housing to provide a double action pump.
  • 8. The fluid pump of claim 5 wherein a ball cage for a ball valve is cast integral and unitary with the bushing.
  • 9. The fluid pump of claim 4 wherein the pump housing bore has a first end and a second end, the pump housing bore being fully machined from the pump housing bore first end.
  • 10. The fluid pump of claim 9 wherein the pump assembly being disposed in the pump housing bore is adapted to be serviced from the pump housing bore first end.
  • 11. A method of making a fluid pump for pumping a volume of fluid under pressure from a fluid source to a fluid dispenser, the fluid pump having an electric motor, a pump drive assembly being operably coupled to the motor for being actuated thereby, a pump assembly, operably coupled to the pump drive assembly and being fluidly communicable with the source of fluid, the pump assembly being actuatable by the pump drive assembly, comprising:forming a single main housing; defining a pump assembly housing therein for housing at least in part the pump assembly; and defining a pump housing, the pump housing being formed integrally with the main housing for housing the pump assembly.
  • 12. A fluid pump for pumping a volume of fluid under pressure from a fluid source to a fluid dispenser comprising:motor drive means for imparting actuating power; pump drive means being operably coupled to the motor drive means for being actuated thereby; pump means, operably coupled to the pump drive means and being fluidly communicable with the source of fluid, the pump means being actuatable by the pump drive means; and single main housing means, the main housing means housing at least in part the pump drive means and having a pump housing means defined therein and formed integrally with main housing means.
  • 13. The fluid pump of claim 12 wherein a fluid housing means is formed integrally with the main housing means.
  • 14. The fluid pump of claim 12 wherein the fluid housing means is formed from a cast metallic material containing an aluminum material.
  • 15. The fluid pump of claim 14 wherein the pump housing means includes a pump housing bore, the pump housing bore defining in part a cylinder, a pump assembly piston being translatably disposable in the cylinder, the piston being formed of a ferric material.
  • 16. The fluid pump of claim 15 wherein the piston is spaced apart from the cylinder to prevent galling of the cylinder during translation of the piston relative to the cylinder.
  • 17. The fluid pump of claim 16 having at least a first bushing disposed in the pump housing bore, the bushing bearing the translation motion of the piston, and a second fluid housing means adapted to operate with the fluid housing means to provide a double action pump.
  • 18. The fluid pump of claim 12, further comprising a second fluid housing means adapted to operate with the fluid housing means to provide a double action pump.
  • 19. The fluid pump of claim 15 wherein a ball cage for a ball valve is cast integral and unitary with a bushing in the pump housing bore.
  • 20. The fluid pump of claim 19 wherein the pump housing bore has a first end and a second end, the pump housing bore being fully machined from the pump housing bore first end.
  • 21. The fluid pump of claim 20 wherein the pump means is adapted to be serviced from the pump housing bore first end.
  • 22. A main housing for use with a fluid pump, the fluid pump having an electric motor, a pump drive assembly being operably coupled to the motor for reducing an output of the motor, a pump assembly being operably coupled to the pump drive assembly and being fluidly communicable with a source of fluid, the pump assembly being actuated by the pump drive assembly, the actuation causing the pump assembly to pump the fluid, comprising:a pump housing being formed integrally with the main housing, the pump housing for housing the pump assembly; and a pump drive assembly housing being formed integrally with the main housing, the pump drive assembly housing for housing at least in part the pump drive assembly, wherein the main housing is a single member housing.
  • 23. The main housing of claim 22, wherein the main housing is cast from a metal material.
  • 24. The main housing of claim 23, wherein the main housing is cast from an aluminum material.
  • 25. The main housing of claim 24 wherein the pump housing includes a pump housing bore, the pump housing bore defining in part a cylinder, the cylinder for receiving a pump assembly piston translatably disposable in the cylinder, the piston being formed of a ferric material.
  • 26. The main housing of claim 25 wherein the cylinder is overbore with respect to the piston to prevent galling of the cylinder during translation of the piston relative to the cylinder.
  • 27. The main housing of claim 26 having at least a first bushing disposed in the pump housing bore, the bushing bearing the translation motion of the piston.
  • 28. The main housing of claim 27 wherein the bushing is die cast of a metal including zinc.
  • 29. The main housing of claim 25 wherein a ball cage for a ball valve is cast integral and unitary with a bushing in the pump housing bore.
  • 30. The main housing of claim 25 wherein the pump housing bore has a first end and a second end, the pump housing bore being fully machined from the pump housing bore first end.
  • 31. The main housing of claim 25 wherein a pump assembly disposed in the pump housing bore is adapted to be serviced from the pump housing bore first end.
  • 32. A fluid pump for pumping a volume of fluid under pressure from a fluid source to a fluid dispenser comprising:an electric motor having a driving output; a pump drive assembly being operably coupled to the motor driving output; pump assembly being operably coupled to the pump drive assembly and being fluidly communicable with the source of fluid, the pump assembly being actuatable by the pump drive assembly; a single main housing, the main housing for housing in part the pump drive assembly and including a pump housing defined therein and formed integrally with the main housing for housing the pump assembly.
  • 33. The fluid pump of claim 32, wherein a fluid housing is formed integrally with the main housing.
  • 34. The fluid pump of claim 32 wherein the electric motor is supportively, operably coupled to the main housing.
  • 35. The fluid pump of claim 32, wherein the pump housing is adapted to be machined from a single direction.
  • 36. A pump main housing for use with a fluid pump, the fluid pump for pumping a volume of fluid under pressure from a fluid source to a fluid dispenser, the pump main housing comprising:a first housing defined therein for housing at least in part a pump drive assembly and including a second housing defined therein, the second housing being a pump housing, the pump housing being formed integrally with the first housing of the pump main housing for housing a pump assembly, wherein the first housing is a single housing.
  • 37. The pump main housing of claim 36, further including a fluid housing being formed integrally therewith.
  • 38. The pump main housing of claim 36 further including support means for operable supportive coupling to an electric motor.
  • 39. The pump main housing of claim 36 wherein the pump housing is adapted to be machined from a single direction.
  • 40. The pump main housing of claim 36 wherein the pump housing is adapted to be machined to facilitate ready extraction of the pump assembly in a single direction.
  • 41. The pump main housing of claim 36, wherein the pump main housing is die cast from a metallic material.
  • 42. The pump main housing of claim 41 wherein the, wherein the pump main housing cast is from a metallic material including the metal aluminum.
  • 43. The pump main housing of claim 37 wherein the fluid housing includes a fluid passageway being fluidly communicable with a fluid pressure sensor.
  • 44. The pump main housing of claim 37 wherein the fluid housing includes a fluid passageway being fluidly communicable with a fluid pressure controller.
RELATED APPLICATIONS

This application is a continuation of application Ser. No. 09/599,678 filed Jun. 22, 2000 (now U.S. Pat. No. 6,435,846), which claims the benefit of U.S. Provisional Application No. 60/161,144 filed Oct. 22, 1999.

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Number Name Date Kind
3307483 Von Plato Mar 1967 A
3614352 Wiese Oct 1971 A
4009971 Krohn Mar 1977 A
4620669 Polk Nov 1986 A
4732548 Iida et al. Mar 1988 A
4755638 Geberth Jul 1988 A
4768932 Geberth Sep 1988 A
4836755 Nitsche Jun 1989 A
4992633 Cyphers Feb 1991 A
5059099 Cyphers Oct 1991 A
5067654 Paige Nov 1991 A
5074467 Geberth Dec 1991 A
5084964 Cyphers Feb 1992 A
5201023 Motzko Apr 1993 A
5228842 Guebeli Jul 1993 A
5282722 Beatty Feb 1994 A
5292232 Krohn Mar 1994 A
5316445 Snetting May 1994 A
5346037 Flaig Sep 1994 A
5435697 Guebeli Jul 1995 A
5472318 Frank Dec 1995 A
5671656 Cyphers Sep 1997 A
5725364 Mirazita Mar 1998 A
5769321 Cyphers Jun 1998 A
5848566 Walsh Dec 1998 A
5934883 Osterloff Aug 1999 A
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Foreign Referenced Citations (1)
Number Date Country
0756902 Feb 1997 EP
Provisional Applications (1)
Number Date Country
60/161144 Oct 1999 US
Continuations (1)
Number Date Country
Parent 09/599678 Jun 2000 US
Child 10/161078 US