US3502029A - Pumps - Google Patents

Description

March 24, 1970 G. HALLADAY 3,502,029

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March 24, 1970 G. HALLADAY PUMPS 4 Sheeizs-SheeI 5 Filed Aug. 8, 1968 INVENTOR.

Grant Holladay BY QQ@ M ATTORNEYS March 24, 1970 Filed Aug. 8, 1968 G. HALLADAY PUMPS 4 Sheets-Sheet 4 wmf A TTORNEYS United States Patent O 3,502,029 PUMPS Grant Hallarlay, 3780 Vinecrest, Dallas, Tex. 75229 Filed Aug. 8, 1968, Ser. No. 751,299 Int. Cl. Flb 17/00, 2.7/04, 9/04 U.S. Cl. 10S-57 17 Claims ABSTRACT F THE DISCLOSURE A pump apparatus for moving liquids from a container having a base mountable on the container to form a cover therefor on which is mounted a reciprocable piston pump which includes a tubular body extending downwardly of the base and having a check valve at its lower end and a hollow piston extending downwardly through the tubular support and having a check valve adjacent its lower end,` upward movement of the pump causing movement of liquid into the body at its lower end past its check valve, and downward movement of the pump causing displacement of the liquid in the body above its check valve into the hollow piston past its check valve. The piston is biased upwardly and is movable downwardly by a motor mounted on the base and a motion translating means between the motor drive shaft and the piston. The upper end of the vertical passage of the tubular piston is connectable by a conduit means, which includes a flexible section, to an accumulator or surge tank having a piston movable against a biasing force to enlarge the effective capacity of the accumulator, as the pressure of the liquid delivered from the upper end of the hollow piston increases, to a pressure sensitive switch device which arrests operation of the motor when the pressure of the liquid delivered by the pump exceeds a predetermined limit, and a discharge conduit provided with any suitable dispensing device such as a spray gun, a grease gun, nozzle, or the like.

This invention relates to pump apparatus and more particularly to a pump apparatus having a reciprocable piston pump.

An object of this invention is to provide a new and improved pump apparatus of simple easily assembled and disassembled structure.

Another object is to provide a pump apparatus having a reciprocable piston pump which is driven by an electric motor.

Still another object is to provide a pump apparatus which is of relatively low weight and has an electric motor for reciprocating the piston which may be run by low voltage direct current so that the pumping apparatus may be driven by the electric current from a battery portable therewith, or from the battery of a truck or other vehicle.

A further object is to provide a pump apparatus having a base mountable on a container to serve as a cover therefor, and a pump which extends downwardly into the container and has an inlet adjacent the lower end thereof whereby liquids are pumped from the container at a location adjacent the bottom thereof.

A still further object is to provide a pump apparatus wherein the pump has a cylinder mounted therein adjacent its lower end above a check valve which permits only upward movement of liquid into the body, the lower end of a tubular piston of the pump being reciprocable in the cylinder and provided with a check valve which permits only upward movement of liquid through the piston, and seal means for sealing between the piston and the cylinder.

An important object of the invention is to provide a 3,502,029 Patented Mar. 24, 1970 pump apparatus of such structure that the wear of the seal means between the cylinder and pump piston and of the surfaces of the pump piston and pump cylinder are minimized even when the pump apparatus is employed to pump liquids having abrasive particles therein.

Another object is to provide a pump apparatus means wherein the seal means sealing between the piston and the cylinder comprises a pair of seal means which are spaced apart a distance greater than the length of stroke or distance of reciprocal movement of the piston in order so that the upper seal means never engages any surface of the piston which at any time moves below the lower seal means.

Still another object is to provide a pump apparatus wherein the pumped liquid is moved from the upper end of the passage of the hollow piston through a conduit means, which includes a flexible section to accommodate the reciprocatory movement 0f the piston, to a discharge conduit whose remote end any suitable discharge or dispensing device, such as spray gun, grease gun, nozzle, or the like, may be connected.

Another important object is to provide a pump apparatus having an accumulator or surge tank in fluid communication with the discharge passage of the pump through which the pumped fluid ows to a dispensing device which is of simple construction and which is not under pressure or strain when the pump is not in operation and which minimizes variations or changes in the pressure of the liquid being delivered to the dispensing or discharge device.

Another object is to provide a pump apparatus wherein the accumulator includes a housing having a piston slidable longitudinally therein to vary the volume of a chamber which is in communication with the discharge passage of the pump and spring means yieldably resisting movement of the piston in a direction to enlarge the chamber, the spring means not being under stress when the pressure in the discharge passage is at atmospheric pressure.

A further object is to provide a pump apparatus wherein the spring means of the accumulator comprise a plurality of conical spring washers disposed about a piston rod of the piston which are compressed between the piston and an end wall of the housing of the accumulator toward a flattened or planar condition by the pressure of the pumped liquid.

A still further object of the invention is to provide a pump apparatus having a pressure responsive switch means to which the pressure of the pumped liquid in the discharge passage is communicated which opens to deenergize the motor when the pressure in the discharge passage exceeds a predetermined value.

Another object is to provide a pump apparatus wherein the pressure sensitive switch means includes a spring biased piston movable in one direction against the force of a biasing spring by the force of the pressure in the discharge passage.

Still another object is to provide a pump apparatus wherein the force of the spring means biasing the piston of the switch means against movement toward position wherein it opens a switch which may be easily adjusted to vary the pressure of the pumped fluid in the discharge passage.

Still another object is to provide a new and improved pump wherein the upper end of the hollow reciprocable piston has a concave cam surface engaged by the cylindrical surface of a motion translating assembly of smaller radius of curvature than the cam surface to provide smooth and substantially noiseless contact between the cylindrical surface and the cam surface.

Still a further object of the invention is to provide a pump apparatus wherein the motion translating assembly includes a circular disc eccentrically mounted on a drive shaft of an electric motor and a bearing assembly mounted on said eccentric disc whose outer race provides the cylindrical surface which engages the concave cam surface of the hollow piston.

Additional objects and advantages of the invention will be readily apparent from the reading of the following description of a device constructed in accordance with the invention, and reference to the accompanying drawings thereof, wherein:

FIGURE l is a side view of a pump apparatus embodying the invention mounted on a container from which the liquid is to be pumped;

FIGURE 2 is a top view, with some parts broken away `and some shown in section, of the pump apparatus of FIGURE 1;

FIGURE 3 is a fragmentary side view of the pump apparatus;

FIGURE 4 is a vertical, partly sectional view, taken on line 4-4 of FIGURE 1;

FIGURE 5 is a sectional view taken on line 5-5 of FIGURE 1;

FIGURE 6 is a fragmentary sectional view taken on line 6 6 of FIGURE 4;

FIGURE 7 is an enlarged sectional view taken on line 7--7 of FIGURE 4;

FIGURE 8 is a sectional view taken on line 8-8 of FIGURE 2; and,

FIGURE 9 is a perspective view of the eccentric disc of the motion translating assembly.

Referring now to the drawings, the pump apparatus embodying the invention which is mountable on the upper end of a container 21 and which pumps liquids from the container at a location closely adjacent the bottom 22 of the container, includes a base 23 of generally circular configuration, as viewed from above or below, having an annular downwardly facing outer surface 24 which is adapted to rest on the annular bead 25 of the container and a circular dependent flange 26 outwardly of the surface 24. A plurality of screws 27 threaded in circumferentially spaced bores 28 of the dependent flange 25 are screwable inwardly through the bores to positions below the bead to prevent upward displacement of the base from the container.

The base has a vertical enlargement or boss 31 provided with a vertical bore 32 through which extends the reduced top end portion 33 of the tubular body 34 of a pump 35. The top end portion is press tted or otherwise rigidly secured in the boss 31 and its upper end extends upwardly of the lower portion of the semicylindrical surface 37 of an arcuate saddle portion 3S of the base to engage the inner end surface 39 of an electric motor 40 which rests in the saddle portion.

A bushing 44 is press fitted or otherwise suitably secured in the enlarged upper portion 45 of the vertical central bore or passage 46 of the pump body 34 and its downward movement is limited by the engagement of its annular bottom end surface with the annular upwardly facing shoulder 47 of the bore. 'Ille top section 49 of the vertically reciprocable piston 50 of the pump 35 is longitudinally slidable through the bushing 44 and is provided with a top concave cam surface 52 which is of greater radius than the outer cylindrical surface 53 of the outer race 54 of a roller bearing assembly 55 whose inner race 56 is mounted in the usual manner on a circular disc 57 provided with a bore or passage 58 offset from the central axis of the circular disc. The disc is mounted on the intermediate portion 59 of the drive shaft 60 of the motor and held thereon by a nut 61 threaded on the reduced end portion 62 of the shaft. Inward movement of the disc is limited by the annular outwardly facing shoulder 63 of the drive shaft at the inner end of the intermediate portion. A key 64 is disposed in the aligned slot 66 of the dise and the slot `67 in the intermediate portion 4 59 of the drive shaft to prevent rotation of the disc on the shaft.

A nipple 70 is threaded in the lateral bore 70a of the piston top section 49 and its inner end opens to the upper end portion of the downwardly open central longitudinal bore 71 of the top section. The pump body 34, the bushing 44, and the boss 31 are provided with aligned vertical upwardly opening slots 72, 73 and 74 through which the nipple extends radially outwardly from the piston top end section and in which it is vertically movable with the piston.

The piston S0 includes a middle section 75 whose reduced upper end portion 76 extends into the enlarged lower end portion 77 of the bore or passage 71 of the piston top section and whose reduced lower end portion 78 extends into the enlarged upper portion 79 of the bore or passage 80 of the bottom section 81 of the piston. The reduced upper and lower portions 76 and 78 of the middle section may be press fitted in the bores of the top and bottom piston sections or otherwise rigidly secured thereto in seal tight relation.

A thrust ring 82 is disposed about the lower reduced portion 78 of the middle piston section and is held against upward movement thereon by the downwardly facing annular shoulder 82 of the middle piston section which defines the upper end of its reduced end portion 78. Downward movement of the thrust ring on the piston iS limited by its engagement with the annular upwardly facing end surface 83 of the bottom piston section.

The piston is biased upwardly in the body 34 by a coil spring 85 whose upper end portion bears against the bottom surface of the thrust washer and whose bottom portion bears against the annular top end surface 86 of a cylinder 87.

The bottom section of the pump piston is provided with an inwardly beveled annular seat 91 which is engageable by a ball check valve 92 engageable with the seat to close the lower reduced end portion 93 of the passage 80 of the bottom section. The check valve is biased downwardly toward closed position by a spring 94 whose bottom end portion is engageable with the ball valve and whose upper end portion engages the downwardly facing annular end surface 95 of the middle piston section. A pair of O-rings 97 and 98 are disposed in the upper and lower internal annular recesses 99 and 100 of the cylinder and engage the external surface of the bottom piston section to seal between the piston and the cylinder. The O-rings are spaced longitudinally a distance greater than the length of the stroke or distance of reciprocal movement of the piston in order that the upper O-ring not contact any portion ,of the surface of the bottom piston section which at any time moves below the lower piston ring 98 for reasons to be discussed below.

The cylinder 87 is disposed in the enlarged lower end portion 103 of the bore 104 of the body and its upward movement therein is limited by the engagement of its annular top end surface with the downwardly facing annular shoulder 106 of the body. The cylinder is held in its upper position in the bore of the body by an annular seat member 108 threaded in the lower end of the bore of the body 34. A gasket or washer 109 of bronze is interposed between the bottom annular end surface of the cylinder and the annular top surface of the seat member to seal therebetween.

The seat member 4108 is provided with an annular beveled valve seat 110 which is engageable by a ball check valve 111 to close the reduced inlet portion .112 of the longitudinal central bore or passage 114 of the seat member. Upward movement of the ball 111 is limited by a pin 115 which extends through aligned radial apertures 116:1 of the seat member and its passage. The seat member has downwardly facing recesses in which the prongs of a suitable tool are insertable to facilitate connection and removal of the seat member.

It will be apparent that the cylinder and the seat member define a longitudinal chamber 116 whose volume is decreased as the pump piston is moved downwardly, thus causing a portion of the liquid present in the chamber to be displaced upwardly into the piston passage. When the lower end of the pump is immersed in a liquid and the pump piston moves downwardly, the ball check valve 111 is moved downwardly and engages the seat 110 thus closing the inlet portion 112 of the bore. The pressure of the liquid in the pump chamber 116, as the piston moves downwardly and thus decreases the volume of the chamber, causes the check valve 92 to move upwardly against the resistance of the spring 94 and the liquid enters into the lower end of the longitudinal passage of the piston formed by the bores 80, 119, and 71 of its bottom, middle, and top sections. Upon the movement of the piston upwardly, the check valve 92 moves downwardly and engages the seat 91 to close the inlet portion 93 of the passage 80 of the bottom piston section and the atmospheric pressure exerted on the liquid in the container causes the ball 111 to move upwardly and liquid to flow inwardly through the bottom reduced inlet portion 112 of the lbore 114 of the seat member to fill the pump chamber as its volume is thus increased.

A strainer assembly 120 may be secured to the lower end of the pump body 34 and includes a ring 121 releasably secured to the body above its bottom end by means of a set screw 122. An inner cup or screen support member 123 has a cylindrical wall 124 and a bottom wall 125 integral therewith. The walls of the cup member are provided throughout their full areas with spaced apertures 125. A cylindrical wire screen 127 extends about the cylindrical wall and a disc shaped wire screen 128 abuts the bottom wall 125 and has a circular annular upwardly extending flange 130 telescoped over the lower end of a cylindrical screen 127 and secured thereto in any suitable manner, as by welding and the like. The screens and the cup are secured to thering 121 by a resilient split retainer ring 132 which has a bottom vertical ange portion 133 adapted to telescope over the upper end of the cylindrical walls, a horizontal portion 134 which extends inwardly from the top end of the bottom flange, and an inner Vertical annular ange 135 which is adapted to abut the external surface of the ring 121. A clamp band 138 extends about the upper flange 135 of the split ring 1.32 and is provided with the usual screw 140 for moving the opposite ends of the clamp band relative to one another to compress the split ring against the retainer ring. The `iluid moving upwardly through the longitudinal passage of the pump piston during each downward movement of the piston flows outwardly through the nipple 70, elbow 142, a iitting 143 which connects the outer end of the nipple to a ilexible conduit 144, the conduit 144 and a litting `145 which are connected to the other end of the llexible conduit. The fitting 145 has an outer end portion threaded in the outer end of a bore or passage 146 in a vertical upward projection or boss 147 of the base. The passage 146 opens to a horizontal passage 148` of the boss 147 and one end of a flexible conduit 149 is connected to the boss 147 by means of a suitable fitting 150 whose threaded end .portion is received in the outer enlarged threaded portion of the passage 148. The outer or remote end of the flexible conduit 149` may have secured thereto any suitable discharge or dispensing device such as a spray gun, a grease gun, nozzle, or the like.

It will be apparent that the communicating passages of the nipple 70, elbow 142, fitting 143, exible conduit .144, fitting 145, and the passages 146 and 148 form a discharge passage for the liquid owing out of the top end of the piston longitudinal passage and by means of which the pumped liquid is directed to the discharge conduit 149.

Since the pump is a single action, single piston positive displacement pump, the liquid is moved up the longitudinal passage of the pump piston only during the downward movement of the piston in each cycle of its reciprocation and an accumulator or surge tank 160, is therefore, provided in order that the pressure in the discharge passage and in the discharge conduit be maintained at a substantially constant value instead of pulsating with each downward movement of the piston. The accumulator includes a cylinder 161 having an outer end cap or section 162, a middle cylindrical section 163 on whose outer end the section 162 is threaded, and an inner end cap or section 165 which is threaded on the inner end of the cylindrical section. An O-ring 166 seals between the end section 165 and the middle section 163. The inner end section has a central threaded aperture 168 in which is threaded a nipple 169 whose inner end portion is threaded in the enlarged outer end portion of a passage 170 of the lboss 147 which opens to the passage 148. The pressure of the -uid in the passage 148 is therefore communicated to the inner end of the cylinder 161 to exert an outward force on a piston 172 slidable in the cylinder whose rod 173 extends rearwardly and outwardly of the cylinder through an aperture 174 of the outer end section 162. The piston is provided with an external annular recess in which is disposed an O-ring. 176 which seals between the middle section 163 and the piston.

Outward movement of the piston in the cylinder toward the outer end section is resisted by a plurality of Belleville spring washers 178 disposed about the piston rod 173. The spring washers are of conical configuration when not compressed and are compressible into a flat or planar shape. The innermost of the washers bears against the end surface 180 of the piston while the outermost of the spring washers bears against the inner surface of the outer end section 162.

When the pressure in the4 cylinder between the piston and the inner end section 165 of the cylinder is at atmospehric pressure, the spring Washers .178 are not under compression and the accumulator may be disassembled without any danger. The use of the spring washers 178 to resist outward movement of the piston in the cylinder permits great pressures to be maintained in the discharge passage of the pump apparatus, for example, 1,0001 pounds per square inch, since the resilient force of the washers is relatively great as compared to the usual coil springs which may be used instead of the washers. If desired, of course, a suitable seal means could be provided in the outer end section 162 to seal between the piston rod 173 and the end section in order that gas maintained under pressure in the cylinder between the piston and the outer end would bias the piston toward the inner end section of the cylinder. In this case, it would *be necessary to introduce gas under pressure through a suitable inlet valve into the outer end of the cylinder to bias the piston toward the end section 165.

The cylinder 161 is held rigid with the boss 147 by the nipple 169 and its cylinder extends through a positioning aperture in a boss of the base. lt will, therefore, be seen that any suitable means may be used to resist outward movement of the piston in the cylinder and that the piston will move forwardly as the pressure in the discharge passage tends to drop as the piston moves upwardly, and then moves outwardly when the piston moves downwardly in the valve body and the pressure in the discharge passage tends to increase to maintain the pressure in the discharge conduit 149 substantially constant.

The base plate has a downwardly extending boss 200, below its top boss 147, which has a vertical passage 201 whose upper end opens to the passage 148 of the top boss and in whose lower end is threaded a bleed valve 202 which has a handle 203. The bleed valve 202 may be a needle type valve and may have an orice or outlet 205 through which the uid from the discharge passage of the apparatus may be released. The vertical passage 201 intersects a horizontal passage 207 of the lower boss 200 in whose outer enlarged end portion is threaded a fitting 208 which connects one end of a connector conduit 209 to the lower boss.

The lower boss is also provided with a second downwardly opening vertical aperture 210 which extends through the lower boss and the u-pper boss and opens to the passage 148. A safety or pressure release valve 212 is threaded in the enlarged lower portion of the vertical passage 210. The safety valve 212 may be of any suitable type as, for example, a ball check valve biased toward closed position with a predetermined force by a spring and which, when the pressure in the passage 148 exceeds the predetermined value, is moved by such pressure to open position to permit exhaust of liquid through the outlet aperture 214 of such valve. The conduit 209 is connected by means of the threaded end portion of a suitable tting 220 to a lower boss 221 of the base, its threaded end portion being receivable in the outer enlarged threaded portion of a horizontal passage 222 of the boss. The horizontal passage opens to a vertical passage 223 of the boss whose lower end is closed by a plug 224 and in whose upper end is threaded an elbow connector 225. The reduced threaded end portion 226 of the elbow connector is threaded in the outer enlarged portion 227 of the longitudinal passage 228 of the tubular body 230 of a pressure responsive switch assembly 231. It will be apparent that the pressure of the liquid in the discharge passage of the apparatus is thus communicated through the conduit 209 to the pressure switch assembly 231.

The tubular body 230 is rigidly mounted on a bracket 234 whose horizontal leg 235 abuts the surface 236 of the base which defines the lower end of an upwardly opening chamber 237 of the base and is secured thereto by means of bolts or screws 240 which extend through suitable apertures in the leg into suitable threaded upwardly opening bores of the base. The tubular body extends through a suitable aperture in the bracket 234 and is held rigid therewith by a nut 245 threaded on the tubular body.

A piston 247 is disposed in the tubular body and has an external ange 248, disposed in the enlarged portion 249 of the longitudinal passage thereof, which engages the annular shoulder 251 of the tubular body to Vlimit movement of the piston to the left, FIGURE 8. The piston is biased in this direction by a spring 253 which extends about the rod 254 of the piston and one of whose end portions bears against the annular shoulder 255 provided by the piston flange 248 and Whose other end bears against the inner end surface 257 of a cap 258 which is threaded on the tubular body. It will be apparent that the force with which the spring biases the piston toward the left may be adjusted by either screwing the cap further on the tubular body or unscrewing it thereon. The piston, of course, is provided with seals such as O-rings 260 which seal between the piston and the tubular body.

The outer end portion of the piston rod extends outwardly of the cap through the central aperture 262 of the cap to engage the operator button 264 of a normally closed switch 265 to cause the switch to open whenever the piston is moved to the right against the resistance of the spring 253 by the force of the pressure communicated to the left end of the passage 228.

The switch is secured to the base by a bracket 265 and a bolt or screw 266 which extends through a suitable aperture in the leg 267 of the bracket into a threaded bore of the base. The base may be provided with enlargements or lower bosses 269 and 270 at the locations of the bores in which the screws 240 and 267 are received to permit use of relatively long screws.

The chamber 237 of the base is defined by an inner vertical wall 272, end walls 273 and 274, and an arcuate wall 275. A switch 276 is mounted on the end wall 274 through a suitable aperture of the end wall and an electric Gable 275a extends through a bushing 276:1 threaded 8 in a suitable aperture in the arcuate wall so that the conductors 278 and 279 of the cable may extend into the chamber. The cable conductor 278 is connected to the metal electrically conductive base by an eyelet 280 and screw 281.

One side of the electric circuit of the direct current motor 40 whose other side is grounded to the housing of the motor is connectable to the cable conductor 279 by the switch 276, the conductor 284, the switch 265, and the conductor 283. The conductor 283 of the motor extends outwardly from the motor connector housing 287 which extends outwardly of the housing and is receivable in a recess provided at one end of the semi-cylindrical surface 37 of the boss saddle portion 38 by the base portion 288. The side wall 272 of the base has a suitable aperture or slot through which the conductor 283 may extend into the chamber 237.

The motor is rigidly secured to the base in the saddle portion 38 thereof by a semi-cylindrical cover and clamp member 290 which has an upper semi-cylindrical portion 291 of substantially the same curvature as the saddle portion surface 37. The member 290 has legs 293 extending laterally outwardly at one side of the lower edge portion of the semi-cylindrical portion and resting on the top surface of the wall 272 which are secured thereto by bolts 294 which extend through suitable apertures in the legs into threaded bores of the wall 272. The semi-cylindrical portion also has legs 294 and 295 which rest on the upwardly facing surfaces of the upwardly extending base bosses 297 and 147, respectively, and are secured thereto by bolts 299 lwhich extend through suitable apertures of these legs into upwardly opening threaded bores of these bosses.

The cover and clamp member 290 at a one end thereof has downward extensions or side walls 301 and 302 which extend downwardly from the semi-cylindrical portion and an end wall 303 which is provided with a downwardly opening slot 304 through which the nipple 70 and the fitting elbow 142 extend outwardly. The side walls 301 and 302 abut the outer surfaces of the boss 297 and the end wall 273, respectively. The semi-cylindrical portion of the cover and clamp member 290 may be provided with a plurality of heat dissipating ribs 306 to dissipate the heat generated by the electric motor during its operation.

It will be apparent that the motor is easily and quickly secured to the base merely by positioning it in the saddle portion 38 of the base, after its conductor 283 has been moved through the aperture in the end wall 272 into the chamber 237, then placing the member 290 thereover, and rigidly securing the member 290 to the base by means of bolts. The cover member is formed of a somewhat resilient metal so that it may exert a clamping force on the motor. The chamber 237 is closed by a cover plate 307 secured to the walls defining the chamber by bolts 308 which extend through apertures of the cover plate into upwardly opening threaded bores of the walls.

A pressure gauge 310 may be provided to indicate the pressure in the discharge passage of the apparatus. The gauge 310 has a downwardly extending inlet 312 which is threaded in an upwardly opening vertical passage 313 of the upper boss 147 of the base whose lower end communicates with its passage 148.

In use, the passage of the elements of the apparatus connecting the passage 228 of the pressure responsive switch assembly 231 with the passage 148 are preferably filled with a ller liquid such as usual automotive antifreeze liquid. If desired, the orifice of the upper end of the vertical passage 201 adjacent the passage 148 may be restricted to minimize mixing of such iiller fluid with the material being pumped. The base of the pumping apparatus 20 is placed over a container so that the pump 35 extends downwardly thereinto and the screws 27 are screwed inwardly until they are positioned below the bead 24 of the container.

During the downward movement of the pump into the liquid in the container, the check valves 92 and 111 are displaced upwardly from their seats and the liquid fills the chamber 116 and also the passage of the pump piston to the level of the top surface of the liquid in the container. The adjusting cap 258 is then rotated in such direction as to cause the spring 253 to exert a predetermined force on the piston flange 248 so that a switch 265 will not open until a predetermined pressure is reached or attained in the passage 248. The conductors of the cable 275 are then connected across a source of direct current, for example, across the terminals of a twelve volt battery. The flexible discharge conduit 149 has a dispensing device, for example, a spray gun or a grease gun, connected to its remote end. The operator then closes the switch 276 and the motor is connected through and across the conductors 278 and 279 through the now closed switches 265 and 276, the motor housing and the base. The motor is preferably a series type direct current motor which has a high starting torque. The rotation of the drive shaft now causes the motion translating assembly to translate the rotational movement of the shaft into a vertical reciprocable movement of the hollow piston 75. Reciprocation of the piston at a relatively high rate, for example, approximately 1500 cycles per minute which is the speed of rotation of the drive shaft of the electric motor, now causes liquid from the bottom of the container to be pumped through the discharge passage of the apparatus and into the discharge conduit 149. Assuming now that the dispensing device is closed, the pressure in the discharge passage, which includes the passages of the nipple 70, the elbow 142, the fitting 143, liexible conduit 144, tting 145, and the base passages 146 and 148, builds up very rapidly and pressure of this liquid is communicated through the nipple 159 to the inner end of the cylinder of the accumulator 160. The accumulator piston will then move in the cylinder towards the cylinder end section 162. Any air which may be trapped within the cylinder will, of course, be compressed as the pumped liquid flows into the chamber of the cylinder. If the dispensing device connected to the remote end of the discharge conduit 149 is maintained closed, the pressure builds up rapidly in the discharge passage until its force, communicated to the piston 228 of the pressure responsive switch means through the base passages 201 and 207, the fitting 208, the conduit 209, the fitting 220, the base passages 222 and 223, and the elbow 225, overcomes the resistance of the spring 253 and causes the piston 247 to move to the right, FIGURE 8, and opens the switch. When the operator now causes opening of the dispensing device, the liquid from the container ows through the conduit 129 moving any air trapped therein out of the discharge conduit and through the dispensing device. If the pressure in the discharge passage of the apparatus drops below the predetermined value, the piston 247 is again moved to the left by its spring, the switch 265 closes, and the pump operates again to maintain the pressure at the predetermined value set by the adjustment of the cap 258. Due to the high rate or frequency of reciprocation of the pump piston, the pump will move the liquid at a high rate and high pressure from the container even though the length of stroke of the piston rod is relatively short, for example, approximately one-eighth of an inch. The accumulator now functions in the manner described above to :maintain the pressure, and therefore rate of flow of the liquid through the dispensing device substantially constant, the accumulator piston reciprocating slightly during each reciprocation of the piston rod.

Should the pressure for any reason exceed a safe value as, for example, if the switch 265 shorts out and will not open, the relief valve 212 will open thus decreasing the pressure in the discharge passage and also directing the liquid back into the container.

The O-rings 97 and 98 which seal between the piston are spaced apart a distance substantially greater than the distance of reciprocation or length of stroke of the pump piston, for example, approximately three-eighths of an inch apart if the length of stroke is one-eighth of an inch, so that the upper O-ring never contacts any portion of the outer surface of the tubular piston which, when the piston is in its lowermost position during a cycle of its reciprocation, is below the line of sealing engagement of the lower O-ring with the piston. As a result, the upper O-ring 97 never engages any such surface which may be scratched or worn by abrasive particles of the liquid, for example, if the liquid being pumped is a paint having pigment particles therein, since the lower O-ring 98 will in effect wipe off such particles and prevent their upward movement past the O-ring 98. In addition, the air trapped below the upper O-ring 97, due to the fluid tight seal provided thereby between the piston and the cylinder, tends to form an air cushion or space preventing any liquid from moving upwardly to the location of the O-ring 97, To further minimize wear of the seal surface of the piston, the cylinder is preferably made of a relatively soft substance such as bronze While the piston is formed of a hard substance such as stainless steel.

It will be apparent, of course, that the spring 84 exerts as great an upward force on the piston as is required by the pump pressure of the liquid to be attained. Pump pressures of over one thousand pounds per square inch can be easily obtained while maintaining a relatively great rate of flow of the uid through a dispensing device.

While the pump has been shown mounted on a base which forms a cover for a container, it will be apparent that the base may be of any suitable shape as required by the environment of its use. For example, if it is used to pump liquids from upwardly open troughs or channels, it may be of rectangular shape and need not cover the full length of such troughs or channels.

After use, the pump apparatus may be easily cleaned by lowering the lower end of the pump into a container of a solvent of the liquid which has been pumped therethrough and then circulating such solvent by means of the pump through the discharge passage of the apparatus and the discharge conduit, back into such container. The passages of the base may be cleaned out by unscrewing the various fittings, nipples, and plugs threaded therein.

The engagement of the concave cam surface 52 of the piston with the peripheral cylindrical surface 53 prevents rotation of the piston about its longitudinal axis so that the fitting 70 connected to the top piston section will be held in proper orientation relative to the base and will not engage the surfaces of the pump body 34, the bushing 44. and the base boss 31 defining their vertical slots 72, 73 and 74, respectively.

It will be apparent that the provision of the concave surface 52 of greater radius of curvature than the radius of curvature of the peripheral cylindrical surface 53 also provides for smoother, more noise free operation of the motion translating device since it provides arcuate areas of contact therebetween even at points of each cycle of rotation of the motor drive shaft wherein the bearing assembly is in extreme laterally displaced position and minimizes the lateral forces exerted on the piston during the rotation of the eccentric assembly.

The foregoing description of the invention is explanatory only, and changes in the details of the construction illustrated may be made by those skilled in the art, within the scope of the appended claims, without departing from the spirit of the invention.

What is claimed and desired to be secured by Letters Patent is:

1.. A pump apparatus including: a base; a pump mounted on said base, said pump including an elongate body having a longitudinal passage therethrough, said body having a rst end portion secured to said base and a second opposite end portion remote from said base, a piston disposed in said body passage for longitudinal reciprocal movement therein, said piston having a iirst end portion extending7 through said rst end portion of said body and a vsecond opposite end portion remote from said first end portion, said body having means in said bodys second end portion providing a piston chamber, said second end portion of said piston being movable longitudinally in said chamber, said tbody having means providing communication between the exterior of said body and said chamber, check valve means in said body for permitting fluid `flow into said chamber from the exterior of the body and preventing iluid flow from said chamber to the exterior, said piston having a longitudinal passage open to said chamber at said pistons second end portion, check valve means in said piston passage for permitting ow of fluid from said chamber into said piston passage and preventing flow from said piston passage into said chamber, and means biasing said piston longitudinally in one longitudinal axial direction relative to said body; drive means mounted on said base and having a rotatable drive shaft; and motion translating means operatively associated with said iirst end portion of said piston and saidrotatable shaft for periodically moving said piston longitudinally in a second longitudinal axial direction opposite said one direction; and conduit means connected to said piston and providing a discharge passage for uids moved through said piston passage during the reciprocal movement thereof.

2. The pump apparatus of claim 1, wherein said motion translating means includes a concave cam surface on said piston having an axis of curvature perpendicular to the longitudinal axis of said piston and circular means eccentrically mounted on said drive shaft and having a cylindrical peripheral surface whose axis of curvature is parallel to said axis of curvature of said cam surface, said cylindrical surface engaging said cam surface.

3. The pump apparatus of claim 2, wherein said circular means includes a disc eccentrically mounted on said drive shaft and a bearing assembly mounted on said disc and having an outer race providing said cylindrical peripheral surface.

4. The pump apparatus of claim 3, and seal means for sealing between said piston second end portion and said means providing said chamber.

5. The pump apparatus of claim 4, wherein said seal means includes a pair of seal means spaced longitudinally relative to said piston a distance greater than the length of the reciprocal movement of said piston.

`6. The pump apparatus of claim 5, wherein said base is mountable on a container and said pump extends downwardly into a container on which said base is mounted, with the second end portion of said body being positioned adjacent the bottom of said container.

7. The pump apparatus of claim 6, wherein said drive means comprises an electric motor and base has a saddle portion providing a semi-cylindrical recess which said motor is positionable with its drive shaft extending over the top end of said piston; and, clamp means securable to said base and extending over said semi-cylindrical recess for rigidly securing said motor to said base.

v8. The pump of claim 7, and an accumulator mounted on said base including a housing providing a longitudinal passage, a piston movable longitudinally in said passage,

passage means communicating one end of said housing passage to said discharge passage, and means in said housing for resisting movement of said accumulator piston in a direction away from said one end of said housing.

9. The pump apparatus of claim 8, wherein said means for resisting movement of said accumulator piston exerts no force on said housing or said piston when said discharge passage is at atmospheric pressure.

10. The pump apparatus of claim 9, wherein said means for resisting movement of said accumulator piston includes a plurality of conical spring washers in said housing 'between said piston and a second end of said housing opposite its one end, said piston having a rod extending through said washers and an aperture provided in said second housing end.

11. The pump of claim 1, wherein said circular means includes a disc eccentrically mounted on said drive shaft and a bearing assembly mounted on said disc and having an outer race providing said cylindrical peripheral surface.

l2. The pump of claim 11, wherein said seal means includes a pair of seal means spaced longitudinally relative to said piston a distance -greater than the length of the reciprocal movement of said piston.

13. The pump of claim 3, wherein said drive means comprises an electric motor and base has a saddle portion providing a semi-cylindrical recess which said motor is positionable with its drive shaft extending over the top end of said piston; and, clamp means securable to said base and extending over said semi-cylindrical recess for rigidly securing said motor to said ibase.

14. The pump of claim 1, and an accumulator mounted on said base including a housing providing a longitudinal passage, a piston movable longitudinally in said passage, passage means communicating one end of said housing passage to said discharge passage, and means in said housing for resisting movement of said accumulator piston in a direction away from said one end of said housing.

15. The pump of claim 14, wherein said means for resisting movement of said accumulator piston exerts no force on said housing or said piston when said discharge passage is at atmospheric pressure.

16. The pump of claim 15, wherein said means for resisting movement of said accumulator piston includes a plurality of conical spring washers in said housing between said piston and a second end of said housing opposite its one end, said piston having a rod extending through said washers and an aperture provided in said second housing end.

17. The pump of claim 1, wherein said drive means comprises an electric motor and base has a saddle portion providing a semi-cylindrical recess which said motor is positionable with its drive shaft extending over the top end of said piston; and, clamp means securable to said base and extending over said semi-cylindrical recess for rigidly securing said motor to said base.

References Cited UNITED STATES PATENTS ROBERT M. WALKER, Primary Examiner U.S. Cl. X.R.

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