US2996014A - Pump - Google Patents

Description

L. E. LEE

Aug. 15, 1961 PUMP 5 Sheets-Sheet 1 Filed OCT.. C50, 1959 mum.

INVENTOR Lul/1er E. Lee

N om

L. E). LEE

PUMP

5 Sheets-Sheet 2 Filed OCT.. 30, 1959 mm. km. mm \mm Gmwwv mv a. R mw@ mn hw .m6 mm wm B\^ mm Q\\\ k m. m mm w o Q E e m mQ L Q MS vS mm. mM/km/ mm mn mn T A@ w mm Imm. n .06m

@v CZMWLU VMS Aug. 15, 1961 L, E, LEE 2,996,014

PUMP

Filed Oct. 50, 1959 5 Sheets-Sheet 5 INVENTOR N Lui/1er E. Lee 2' @M BY M www ATTORNEYS Aug- 15, 1961 9E. LEE 996,014

' PUMP Filed Oct. 3Q, 1959 5 Sheets-Sheet 4 Y INVENTOR ATTORNEYS Aug. 15, 1961 L. E. LEE 2,996,014

PUMP

Filed om. so, 1959 5 sheets-smet 5 INVENTOR Luther E. Lee

97 BY (Q.

ATTORNEYS United States Patent O 2,996,014 PUMP Luther E. Lee, 6625 Eastern Ave., Takoma Park, Md.V Filed Oct. 30, 1959, Ser. No. 850,004

11 Claims. (Cl. 10S-49) (Granted under Title 35, U.S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to a pump and more particularly to a new and improved pump similar to the pump disclosed and claimed in Patent 2,802,424, and is suitable for use with a machine tool such, for example, as a lathe, drill press, milling machine, and deep hole drilling machine for supplying a concentrated directed stream of high velocity pressure uid onto a cutting tool or within the proximate vicinity thereof during a cutting operation. Moreover the pump is admirably suited for pumping high octane gasoline or other highly inflammable fluids in large quantities under low pressure.

Increased production with superior finish and prolonged tool life have long been objectives sought in the machine tool industry. Thus far, however, each of the above factors have been limited by the other factors involved. For example, prolonged tool life normally requires slower operating speeds, and superior iinishes necessitates smaller cuts and therefore reduced production. Thus the attainment of one objective has been achieved only by the loss of another objective. Ordinarily, the actual manual operation time to perform a metal working function is consumed in making a number of adjustments as the Work progresses, returning the cutting bit for another cutting stroke, and regrinding and resetting the bit as it Wears.

It is contemplated by this invention that by the use of a directed relatively high pressure iluid coolant projected from an appropriately located nozzle to an area immediately proximate the cutting edge of the tool bit and the work, appreciably greater tool life and higher rates of metal working will be realized thus contributing to increased production and greater economy.

An object of the present invention is to provide a new and improved high pressure fuel pump suitable for use with a machine tool or the like.

Another object of the invention is to provide a fluid pressure pump for projecting a coolant fluid under high pressure to the area adjacent the cutting edge of a toolbit to prolong tool life at increased working rates.

A further object of the invention is to provide a pumping means actuated by low pressure fluid and operative to supply a iluid at the outlet side thereof at relatively high substantially constant pressure. I

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection With the accompanying drawings wherein:

FIG. 1 is a view in vertical section of a jacket or container suitable for use with the pump of the present infvention, the pump being disposed therein and shown in elevation;

FIG. 2 is a side elevational View of the device of l, with the container removed;

FIG. 3 is a plan view of the device of FIG. 2;V

FIG. 4 is a transverse sectional view taken on the line 4 4 of FIG. 2;

FIG. 5 is a transverse sectional view taken on the line 5 5 of FIG. 1;

2,996,014 Patented Aug. 15, 1961 ICC FIG. 6 is a transverse sectional view taken on the line 6-6 of FIG. l with the container removed;

FIG. 7 is a longitudinal sectional view taken on the line 7 7 of FIG. 3; v

FIG. 8 is a longitudinal sectional view taken on lthe line 8 8 of FIG. 3;

FIG. 9 is a longitudinal sectional view taken on line 9 9 of `FIG. 4;

FIG. 10 is a transverse sectional view taken on the line 10-10 of FIG. l with the container removed; Y

FIG. 11 is an enlarged detailed sectional view of the combination pressure operated piston and ball check valve;

FIG. 12 is an enlarged fragmentary detailed sectional view of one end of the differential pistons of the pump construction;

FIG. 13 is an enlarged fragmentary sectional view of one of the adjustable check valves employed in the pump;

FIG. 14 is a View similar to FIG. 11, illustrating an alternate arrangement of the -valve of FIG. 11; and

FIG. 15 is a diagrammatic illustration of the pum system of the present invention. i

Referring to the drawings, and more particularly t FIG. 1, the numeral 10 generally indicates the pump constructed in accordance with the present invention and adapted to be attached to a conventional engine lathe such, for example, as disclosed in Patent No. 2,854,822, filed January 18, 1955, for Pneumohydraulic-Electric System. Moreover, the pump 10 of the present invention is constructed and arranged to develop a relatively high pressure and to deliver a uid at high pressure through a system of conduits and control valves to a nozzle assembly mounted on the toolholder of the lathe, the aforesaid nozzle assembly being designed so as to direct the high pressure fluid adjacent the cutting surface of a toolbit at a high velocity and a pressure in excess of 900 p.s.i. to provide and maintain a cooling effect along the -vital tool surfaces by removing the generated heat with sucient promptness to prevent `any appreciable heat effects that might injure either the tool or the work. z,

Furthermore, by providing a reciprocating pump re- Sponsive instantaneously to wide fluctuating demandsa high pressure machine tool head may be maintained substantially constant throughout the operations so that lluid operated elements on an associated lathe or other apparatus are supp-lied with suicient and uniform uid pressure under varying loads.

The pump 10 comprises a casing or block 11 having axially displaced cylindrical chambers 12, 13, 14 and 15 formed therein, and in which a pair of differential working piston assemblies are slidably retained andv reciprocated in response to iluid under pressure. The differential working piston assemblies are provided with low pressure intake pistons 16 and 18 and high pressure discharge pistons 17 -and 19 and are arranged so that the pistons will be slidable in a direction parallel to veach other when retained in their corresponding cylindrical chambers. A jacket or container C surrounds the pump casing 10, the walls of the container being in spaced relationship with respect to the casing 11 to provideva tluid reservoir R, FIG. 1. Container C, if desired, may be provided with a sight opening whereupon visual inspection of the fluid level within reservoir R may be made. As is more clearly shown on FIGS. 7 and 15 the low pressure pistons are spaced from and connected to the high pressure pistons by elongated` piston rods 21 and 22. The piston lhead surface area of the workingpistons16, 18 and 17, 19 are constructed and arranged so as to transmit as by hydraulic ram action the summation forces acting upon the relatively large piston Vface areas by a relatively low pressure Iactuating fluid through the elongated piston rods to the relatively small piston head surface areas to act upon a fluid within the elongated small piston chambers.

A cover or plate member 23 is secured to the upper fendof casing 11 as'by bolts 24, the vcover being provided with a pair of mutually spaced bosses 25 and 26, boss Af2.5 being in alignment with the chamber 12 and boss 26 being in alignment with chamber 14,`th`e chambers being -:sealed by a gasket 27 disposed `between the upperend of the casing 11 and the plate 23. As more clearly shown Io'n FIG.:7, each` boss'2f5V and 26 is provided with a centrally'fdisposed'bore-0r'bulfer chamber 28,V sealed by `agasket `29 and 1a closure'member 31 secured"to"the -bos`ses"as by bolts 32. Disposed within each' of the chambers 28 is a buier or piston element 33 having a pistn' `head 34 slidably vdisposed Within chambers 28 y anda/stein or Vshaft 35 slidably `disposed within openings 36 formed in plate 23 and extending into chambers "12Y and 14, respectively. i' is'sshown on'FIG. 4, a slide valve assembly generally indicated by the reference character 37 and comprising a `casing orl housingS is *secured to the block 11, as by bolts 39, the 'slide valve being constructed and arranged fto control low pressureintake and exhaust'to'the various pressure responsive devices used in the pump construcrtionand'which will be hereinafter more fully described. -The end ofthe casing 38 has longitudinally disposed bores orrece'sses formed therein to provide cylindrical chambers 'Y41/'and`42. The central portion of casing 38 isV milled .out rtoprovide a rectangular iluid inlet plenum chamber '43;' Axially movable within the casing 38 lis a valve -stern'V 45, the terminal ends thereof 'carrying' pistons 46 and 47, FIGS. 4 and 5. VThe piston 46 is slidablewithin A'chamber 41, and piston 47. is slidable within chamber 42. fAthrottle or block valve 48 is disposed between a pair of "mutually spaced enlarged cylindrical Yportions 49 l'formed on the stem 45 and engages the stem fby reason of -a "'semicircular groove V51 provided therein, as is vbest shown on FIG'.` 8.

The throttle valve 48 is'provided with arec'ess or -passageway 52, FIGS; 4 and 15, which straddles the uid exhaustport or passageway 53 and uid intake ports or passageways 54 or 55 to exhaust the actuating fluid medium, the uid medium being supplied to' Vchamber 43 -by way of`low pressure line 56 inthreaded engagement with casing"38, vas at 57 and exhausted by way'of pipe 50 jthreaded into VVcasing 38, as at 50'. The throttle valve 48 isV movable in lirst one direction and then in a reverse -drection inresponse to movement of the slide valve 37 -during operation'of the pump. Therefore, the position of the exhaust port 53 will be disposed 'in recess 52 vof the valve 48, with either the lluid vintake port`54 or 55 in communication with the exhaust port'53 during'the axial -shiftingof the valve 48 from'one position to the other `position. 'ReferringV to FIG. 4, the terminal ends of'the -casing 38 adjacent'bor'es`41 and 42fare sealed-'by a plosurefplate 58 and a gasket 59 secured tothe casing, as by'bolts'61. Each plate 58 carries a butler or actuatf'ing'fdevice 62 vprovided with a stem 63s1idably disposed withincentrally disposed bores or' guideways 64 formed y'1`11-'p1ates'58 and sealed by O-rings or the like 65. The stems 63 are provided with heads or buffer elements 66 Ydisposed Within bores 41 and 42 respectively, to manuallyfoperate the slide valve 37, andY to absorb the shock -as'*piston' heads 46 and 47 moveinto engagement' there- `with-during uid operation of the pump.

shown in FIGS. 9 and l5, a pair ofl low pressure iluid control valves generally indicated-by the numerals 167 and' 68 are disposed and arranged on eacheside fof casing 11.` rv'Iihe'valves 67 and 68flare videntical-in 1,x'truct'reand-'includea pair of-rnutuallyspaced inserts' or eves7273`, a'ball Ycheck'74 normallyfbeinginjen- *agementwith afseat'75V formed in'sleeve 72 and'rnovable 4`i1f0"'c'ga'gemenVwith s'eat'76. The'valv'es i'1d""68 further include a piston 77 having a stem 78 adjustably mounted therein and extending through and loosely disposed in a passageway 79 formed in sleeve 73 with the terminal end of the stem in engagement with the ball check 74 to maintain the ball check in engagement with seat 75 and a spring 80 disposed between sleeve 73 and piston'77 to move the piston 77 Vand stem 78'an amount suflicient to allow'the ball check'to engage its seat in sleeve 73. Valve 67 operates in a bore formed in casing 11, which bore is provided with chambers 81, 82 and 83, and valve 68 operates in a similar bore Yformed in thetcasing 11, this bore being provided with 'chambers V84,- 85 and 86. -Chamber83 in valve 67 is in communication with chamber 82 by way of passageway 79 in sleeve 73, and chamber 86 in valve 68 is in communication with chamber 85 by way of passageway 79' in sleeve 73, as Eshown in FIG. 15. It will befunther noted in FIG. l5 -that chamber 83 in valve 67 and chamber 41 in slide valve 37`are'connected by a'passageway or portv 87 and chamber 86 in valve68 and chamber-42m slide valve'37 are convnectedby passageway or port 88. VPassageways or vents -89 connect chamber 821m valve 67 and chamber 85 in valve 68, the aforesaid vents'beingin communication with the'exhaust'port 53'. Fluid communication between vthe lowermost end of valve 67 to chamber 12 is established by a passageway 91, and between chamber 81 at the -upper end thereof and chamber 12 by a passageway'92, A`valve 68 being also provided vn'th identical vpassageways '91;92 to establish -uid communication between the lowermost Cend of valve 68 and chamberv 14 and between chamber 84 attheupper end thereof Vand chamber 14. `Asis best illustrated in FIGS. 5 and 8 a filter assembly Ygenerally indicated by the reference character 93 is mount- 'ed on the 'casing 11, the lfilter assembly comprising an annular flange 94secured-to the casing 11, as by bolts '95'and having-'a plurality of ribs 96 extending outwardly therefrom which support a plate 97 at the terminal end thereof and an annular member 98. Supported by the *aforesaid ange 94, annular member'98 and plate 97 and in spaced relation with respect to the ribs 96-is an oil filter device 99, composed of any material suitable for the purpose such, for example, as iine mesh wire screen. The Yfilter assembly 93 further comprises'uid pressure actuated dasher or agitator 100, FIGS. 4 and 8, having fmedium'within the lter 99 is directed against'the filter #with sufficient force, by reason of the construction and arrangement of the member 105, to remove and maintain the filter free from all foreign matter.

- As-shown inFIGS. 8 and l5, the casing 11 is provided 'lwith a recess or vWell- 109 which is substantially `semifcirc'ular, the well bordering-on fthe filter assembly 93 and fn communication with reservoir R in container C and with a reservoir by way of'passageways 111 and 112 -formed in casing 11, the reservoir 110 being sealed and secured to the lower end of casing 11, as by a gasket 113 land bolts 114. It will be understood that during a pumping cycle fluid flows from the reservoir in container C Athrough filter 99 and into reservoir 110.

Turning now to FIG. l5, passageway 54 communicates with the lower end of chamber 103 in casing 11, with one of the buffer chambers 28 provided in cover-23 by way of "passageway"`` and"with'chamber w14 for the working Apiston 18 by way of passageway 116. Passageway 55 'communicates with the uppermentni of chamberl`103 -in casing 11, and with the other buler Vchamber 28 provided in cover 23 by way of passageway 117, and with chamber 12 for the working piston 16 by way of passageway 118.

A pair of mutually spaced metering valves 119 and 121 are mounted on casing 11, as best shown on FIG. 6, each valve comprises an adjustable stem 122 in threaded engagement with a nipple or sleeve 123 carried by casing 11 and having an annular groove 124 formed thereon which terminates in a conical valve head 125 disposed in a chamber 126 having a valve seat 127 therein for cooperation with the valve head 125. Spring urged ball check valves 128 are disposed within bores 129 formed in the casing 11 adjacent each of .the metering valves 119, the ball checks being normally in engagement with seats 131 and the bores 129 being sealed by plugs or the like 132. Fluid communication is established from passageway 54 to chamber 126 of metering valve 119 by a passageway 133, from chamber 126 to bore 129 by passageway 134, from bore 129 to passageway 92 by a passageway 135, and from chamber 126 to chamber 13 for the working piston 17 by a passageway 136. Fluid communication is established from passageway 55 to chamber 126 of metering valve 121 by a passageway 137, from chamber 126 to bore 129 by a passageway 138, from bore 129 to passageway 91 by a passageway 139, and from chamber 126 of valve 121 to chamber 15 for the working piston 19 by a passageway 141.

Ball checks generally indicated by the numeral 142 are arranged on the lower end of the casing 11, the valves 142 being disposed within the reservoir 110 and in communication with the high pressure working piston cylinders 13 and 15 by uid intakes or suction passages 143. As more clearly shown on FIG. 13 each of the valves 142 comprises a tubular nipple 144 in threaded engagement with casing 11 and having a ball 145 disposed therein and normally maintained in engagement with a seat 146 by a spring 147, one end of the spring being in engagement with the ball 145 and the `other end thereof being in engagement with an apertured plug 148. The desired spring pressure on ball 145 may be obtained by adjusting the plug 148. Furthermore, by the aforesaid intake valve arrangement, it will be understood that the uid medium, such, for example as oil or the like, is admitted into the high pressure working piston cylinders 13 and 15 during the pumping cycle. It will be understood that the oil may be supplied to the reservoir R in container C in any suitable manner such, for example, as by a pipe 150, FIG. l.

A fluid loutlet pipe 149 is threaded into the casing 11 and communicates with a passageway 151 which in turn communicates with a pair of bores 152. Disposed within each bore 152 is a ball check 153 maintained into engagement with a seat 154 by a spring 155, and adapted to be moved out of engagement with the seat 154 during a pumping cycle to permit oil to be exhausted from cylinders or chambers 13 and 15. The bores 152 communicate with passageways 143 by way of passageways 156 and are sealed by plugs 157, FIG. 10. By the aforesaid outlet valve arrangement, it will be understood that the oil or other suitable uid medium is discharged from the high pressure working piston cylinders 13 and 14.

It will be noted on FIGS. 7 and `15 that each of the high pressure pistons 17 and 19 is provided with an annular groove 158 and having an O-ring 159 disposed at each side thereof, the O-ring being composed of any material suitable for the purpose such, for example, as Teflon. Each piston is further provided with a cup-shaped member 161, composed of Teion and having a conical element 162 integrally formed therewith and disposed in a complementary recess 163 formed in the end of the piston, as best shown on FIG. 12. The member 161 is secured to the end of the piston by a bolt 164 in threaded engagement therewith, as at 165 and provided with a head 166 in engagement with a washer 167. Disposed in a conical recess 168 in member 162 is a sealing gasket 169 such, for

. example, as an O-ring, the O-ring 169 being compressed 6 by the washer 167 into sealing engagement with the bolt, washer and conical recess as the bolt is threaded into the piston. It will be understood that by the O-ring arrangement 159 and the Teflon cup-shaped member 161 low pressure fluid is prevented from entering low pressure chambers 12 and 14 during a pumping operation.

It will be noted on FIG. 7 that the chambers 13 and 15 are each provided with a sleeve or insert 171 composed of any material suitable for the purpose such, for example, as brass, steel, bronze or kthe like, the inserts may be rem'oved and larger high pressure pistons may be employed in chambers 13 and 15 in lieu of pistons 17 and 19, if desired.

In the arrangement of FIG. 14 a valve generally indicated by reference character 172 may be employed in lieu' of the aforesaid valve 67-68. This valve comprises a piston assembly 173 movable within chambers 170 and having a stem 174 which carries at one end thereof a piston head 175 provided with a ring 176, composed preferably of Teflon, the other end of the stem carries a sealing head 177 provided with an annular penetrating or sealing element 178. Disposed within one end of the aforesaid chambers is a plug or sleeve 179, having a centrally disposed bore 181 extending therethrough in communication with the passageway 91. A sleeve 182 is press-fitted into the bore 181 and carries a seat 183, composed of any material suitable for the purpose such, for example, as Teflon, the annular element 178 on stem 174 being adapted to penetrate the seat 183 an amount suiciently to provide a sealing connection therebetween in response to a predetermined pressure applied to the piston assembly 173. lIt will be understood that passageways connecting the valve 172 to the various components of the pump will be similar to passageways 87, 89, 91 and 92, as shown in low pressure control valves `67-68.

Referring now to FIG. l5 for a more complete understanding of the operation of the pump, the reservoir R in container C is provided with a quantity of suitable fluid to be pumped during the pumping cycles. When the slide valve 37 is in the position, as shown on FIG. 15, a suitable low pressure fluid medium, such for example, as compressed air is admitted into the plenum chamber 43 in slide valve 37 by way of inlet line 56. When this occurs pressure from chamber v43 is admitted into chamber 103 in the agitator assembly by way of passageway 54, into the buier chamber 28 for working piston 16 through passageway 115, into chamber 14 for Working piston 18 via passageway 116, into chamber 81 of control valve 67 through passageway 92, and into chamber of working piston 16 by way of passageway 133, metering valve 119 and passageway 136. The pressure to chamber 12 is cut-olf when piston 17 reaches the position, as shown in FIG. 15, with the passageway 136 in registration with the groove 158 in piston 17 and sealed-olf by rings 159 disposed on each side of the groove 158. When this occurs the aforea said chambers 103, 28, 14,81 and that portion of chamber 12 below piston 16 are pressurized. However, that portion of chamber 12 above piston 16 has very little, if any, pressure therein at this time since the pressure previously supplied thereto has been exhausted during upward movement of piston 16 to the position shown in FIG. l5.

During this cycle of operation of the pump, the ball check 74 of control valve 67 is maintained in sealing engagement with seat 75 by the piston and stem arrangement since the pressure in chamber 81 `acting on the piston maintains the stem in engagement with the ball check. When the valve 67 is in this position, communication between chamber 41 in the slide valve `37 and chamber 83 in the valve 67 is by way of passageway 87 and communication between chamber 82 in valve 67 and exhaust passageway 53 is by -way of passageway or vent 89. It will be further noted that when the working piston 18 is in the position shown on FIG. l5, pressure is exhausted from chamber 12 by way of passageways 118, 55, chamber 52 in the throttle valve 48, port 53 and pipe 50, from 7 buffer -chamber 28 for working piston 18 -by way'of passageways- V 117, 55,chamber 52 in -throttle valve'48, port 53 andv pipe 50, from chambers 1'4 by way-ofpassageways 92-139,'ball check 128, passageways- 137-55,

chamber 52 in throttle valve 48, port 53, and pipe 50,

from chamber 15 by Way of passageway 141, metering valve 121, passageways 137-55, chamber 52 in throttle valve-48, port 53v and pipe 50, from chamber 103 of the agitator assembly by way of passageway 55, chamber'SZ in throttle valve 52, port 53, and pipe 50, and from charn- -A'ber84 in control valve 68 by way of passageways 92- f'139, ball check128, passageways 137-55, chamber 52 in throttle valve 48, port 53 and pipe 50.

After ethe aforesaid exhaust cycle, 'ball check 74 of -control valve-68 -is forcibly moved into sealing'engage- "ment with seat 76 Vformed in sleeve 73 by the pressure A4from chamber 14 as the piston moves beyond passage- "way 91. When this occurs vent pipe S9 for chamber 85 fissealed-oiand thus the pressure is admitted into chamber 42 of slide valvey casing 38, forcing the slide valve toward the left. During the movement of the slide valve Yto the left, `the ball check 74 of valve 67 is maintained 'in sealing engagement-with seat 74, whereuponthe pressure created by the movement of the slide Valve will be *exhausted by way of passageway-87, chamber 83, bore `73, chamber 82, passageway 89, chamber 52, port 53 and vpipe 50.

When Vthe slide-valve hasy been moved to the left vin the aforesaid manner recess 52 in throttle valve 48 bridges `Vexhaustfport -3 and passageway 54,'and thus a reverse 4cycle of operation of the pump will occur whereupon piston 16 will be moved in -a downward direction and Y piston 18 will be'moved in an upward direction. During this' cycle of operation the agitator 101 within chamber 103 of the lter assemblywill be moved in a downward direction, ball check 74 in control valve 68 will remain in sealing engagement with seat 75 and-ball checkV 128 `4will remain closed and thus this cycle of operation is substanti-ally the same as vwhen the slide valve 37 is in lthepositionshown in FIG. l5. During'thisv cycle of operation,V however, the passageways formerly used for exhaust'lines will now 'become a low pressureline, and the passageways formerly used for a low pressure line will now become an exhaust line. In other words the pressure and exhaust passageways are Ialternately-shifted AVfrom one totheother in response to the movement of slide valve 37V and Vpistons 16-18 from one position to the other.

During upward movement of piston 17, uid from'reservoir 110 is admitted into chamber 13'by way vof check valve 142 and passageway 143 and, concurrently therei with and during downward movement'of piston 19', iluid Vis exhausted from chamber by way of passageway 156,

'check valve 15-3, passageway 151 land pipe 149. Upon upward movement of piston 19, uid from reservoir 110 'is' admitted into chamber 15 by check valve 142 and passageway 143 and concurrently therewith and during movement of piston 17 uideis'exhausted from chamber 13 by'way of passageway `156 `and check valve 153.

Fluid is supplied to reservoir 110 by way of recess 109, y'and passageways 111-112 during the suction strokes Vof piston 17 and 19, the' iiuid being thoroughly cleaned as thev'uid lpasses through screw 99. Furthermore, dur- `ing theY 'pumping operation piston 101 is reciprocated Vwitl'iin-chamber-103 as pressure is alternately admitted n'arid 'exhausted 'therefrom'in'wthe aforesaid manner. In responsetothemovement of piston 101, the agitator disposed within filter screen 99 and having an inclined wall 107 and .openings`106-in the bottom wall thereof agitates I'the fluid suihciently to prevent foreign matter for collec- -r tion )on the screen thereby to assure a continuous flow of cleanfuid' into the reservoir 110.

Obviously many/modiiications and variations of the vrpresent invention Aare possible in the light of the above teachings. Itis therefore to` be understood''that''withinJ A*8 -the' scope of the appended claims theinvention may be practiced otherwise than as yspecifically described.

What is claimed is:

l. A fluid' operated reciprocatingpump comprising: diierential working pistons each Vhaving selectively pro- -portioned surface areas, said pistons being Ymovable vby a low pressure lsupply uid to pump a uidmedium Yto increase the discharge pressure lthereof, uid actuated `means Yoperated by said iiuid in accordance with Ythe position of said pistons, means including a passageway vin communication with said fluid actuated means vand each of said working pistons and functioning as anv inlet in accordance with the position-of said pistons, fluid operatedmeans controlled by said working pistons, said `iluid operated means including an additional lpassageway in'communication with each of said working pistonsand the fluid actuated means and functioning as an exhaust in accordance with the position of said pistons and fluid operated means, port means in communication with said uid operated means and said luid actuated means for venting said uid operated means in accordance with the position of the pistons and the fluid Voperated means, filter means carried by the, pump and disposed within the uid medium, and agitating means 'disposed' within `the lter'means and controlled by said Working pistons for agitating Ythe uid medium an lamount sutlicient to prevent foreign matter from accumulating on the lter means.V

2. A Ypump according to claim 1, including a fluid actuated buffer means Vfor each of said working pistons, a passageway between said uid actuated Ameans and butter means, said passageway `functioning as inlet and exhaust line'in'accordance with the position of said iiuid actuated means and the working pistons.

3. A pump according to claim y1, including manually operable shock absorbing means cooperating with said fluid actuated means.

4. A constant pressure fluid pump comprising; a block having a plurality of laterally spaced and selectively proportioned cylinders therein, fluid actuated reciprocating differential working pistons disposed parallel to -each other, each of said working pistons having a relatively large low pressure uid receiving chamber at one end and a relatively small high Vpressureiiuid pumping surface at the other end thereof, a slide valve in iluid driv- -ing communication with said pistons to controlthese- .quence of piston reciprocation through the supply and exhaust of the piston actuating fluid, a fluid regulating valve in fluidcommunication with said high pressure chamber and said slide valve for admitting said low pressure therein, a control valve in uid communication with said low pressure therein; a control valve in uid communication with said' low pressure chamber and said slide valve. for conveying the driving iluid thereto, an exhaust 'valve in uid communication with said low pressure chamber, the control valve iancl'saidV slide valve for exhaustingV the actuating fluid from said low pressure `chamber, a reservoir'in'said'block `from-which a uid vmedium is to. be pumped `during a'pumping operation, a supply passageway in-uidcommunicationwith said reservoir and' theV highA pressure cylinders, Ya discharge passagewayin fluid communication withy the'high pressure chambers Vand aV dischargeport, and-check .valves 'in said`r` supply anddischarge passagewaysfto maintain the flow ofl theviluidmedium'in a predetermined path. 5. Arconstant :pressure hydraulic pump comprising; a low pressure 'fluid supply line, adjustable -means disposed in said line .for controlling the amount-of saidfuid Vilowing `therefrom, a-housing block with spacedflow pressure cylinders therein, low pressure vpistons slidably retained for movement in said cylinders, 'piston rods'car- 'ried' by and` extending from said pistons, yhigh pressure cylinders proportionally reduced with respectto said low pressure cylinders, highfpressure pistons integrally formed' with'said rods and slidably retained'withinsaid high pressure cylinders, a ,acket forming a reservoir surrounding said housing block, fluid passageways from Said reservoir to the high pressure cylinders, check valves in the fluid passageways to direct iluid ow in a predetermined path, slide valve means selectively operated with and fluid actuated through the movement of the alternately reciprocating pistons in the low pressure cylinders, rst valve means in fluid communication with said low pressure and the slide valve and operated by said uid as said low pressure piston moves a predetermined amount for controlling the operation of said slide valve, and second valve means in fluid communication with said low pressure chamber and said slide Valve for controlling the exhaust of the uid from said low pressure cylinder when said low pressure piston has moved said predetermined amount and said first valve means are operated, a passageway interconnecting said first valve means in communication with said slide valve for venting the rst valve means as said first valve means are operated, and means on said high pressure pistons alternately admitting7 and sealing off the low pressure uid supply line at predetermined intervals during the reciprocation ofthe pistons.

6. A constant pressure Huid pump comprising: a block having a plurality of laterally spaced and selectively proportioned cylinders therein, uid actuated reciprocating differential working pistons disposed parallel to each other, each of said working pistons having a relatively large low pressure fluid receiving chamber at one end and -a relatively small high pressure iluid pumping surface at the other end thereof, a slide valve in uid driving communication with said pistons and alternately moved from one position to another position to control the sequence of piston reciprocation through the supply and exhaust of the piston actuating uid, la fluid regulating valve in duid communication with said high pressure chamber and said slide valve for admitting low pressure fluid therein, a control valve in uid communication with said low pressure chamber and the slide valve for conveying the driving iiuid thereto, an exhaust valve in fluid communication with the low pressure chamber, the control valve and the slide valve for operation by the low pressure fluid to exhaust the uid from the low pressure chamber, a reservoir surrounding said block and containing a quantity of uid therein to be pumped, an inlet passageway in communication with said reservoir and the high pressure chamber, an intake valve in said passageway to maintain the ilow of fluid medium constant from said reservoir into said high pressure cylinder during a pumping operation, `a discharge passageway in communication with said high pressure chamber, a discharge valve in Said discharge passageway to maintain the iiow of iluid medium const-ant from said high pressure cylinder during said pumping operation, and further passageway in uid communication with the control valve and the slide valve for venting the slide valve as the slide valve is alternately driven from said one position to the other position.

7. A pump according to claim 6, including a buifer chamber, a buffer disposed within said buter chamber and cooperating with said working pistons to limit the movement thereof in an upwardly direction during said pumping operation, port means in communication with said buer chamber and said slide valve and controlled thereby to alternately admit and exhaust the actuating fluid from the buier chamber during said movement of the slide valve from said position to the other position.

8. A constant pressure uid pump comprising; a block having a plurality of mutually spaced and selectively proportioned cylinders therein, uid actuated reciprocating differential working pistons disposed parallel to each other, each of said working pistons having a relatively large low pressure uid receiving chamber at one end and a relatively small high pressure uid pumping surface at the other end thereof, means including a slide valve in fluid driving communication with said pistons to control the sequence of piston reciprocation through the supply and exhaust of the piston actuating fluid, adjustable fluid regulating means in fluid communication with said high pressure chamber and said slide valve for controlling the amount of actuating fluid entering said chamber, a control valve in fluid communication with said low pressure chamber for conveying the driving fluid thereto in accordance with the position of said pistons, an exhaust valve in iiuid communication with said low pressure chamber, the control valve and said slide valve for exhausting the actuating fluid from the low pressure chamber in accordance with the position of said piston, a container in said block and having a quantity of uid medium therein and to be pumped therefrom during a pumping operation, a supply passageway in communication with the container and the high pressure cylinders, a discharge passageway in fluid communication with the high pressure chambers and a discharge port, and check valves in said supply and discharge passageways to maintain the flow of the duid medium in a predetermined path during said pumping operation, and a supply reservoir surrounding said block in fluid communication with said container for supplying said fluid medium to the container during said pumping operation.

9. A pump according to claim 8, including filter means carried by said block and disposed within said fluid medium in the jacket, an agitator carried by said block and slidably arranged within a chamber formed in the block, said agitator being disposed within said filter and reciprocated in response to actuating fluid Ifor agitating said uid medium in said reservoir an amount sufficiently to remove foreign matter from said lter, passageways in uid communication with said chamber and the slide valve and controlled by the position of said slide valve for alternately supplying and discharging the actuating fluid from said chamber during reciprocation of said agitator.

l0. A pump according to claim 8 wherein said agitator includes a stem slidably disposed in said block and having a piston formed on one end and a fluid agitat'ing member on the other end thereof, said member having an annular inclined wall and a plurality of openings extending therethrough.

ll. A constant pressure fluid pump assembly comprising; a source of low pressure uid, a reservoir containing a quantity of fluid medium to be pumped, a supply means in fluid communication with said reservoir for supplying the fluid medium to be pumped from said reservoir, discharge means for high pressure uid medium, an exhaust vent including a ball check for venting low pressure fluid, pump means for pumping high pressure fluid medium from said reservoir to the discharge means, valve means in fluid communication with the pump means for alternately connecting the pump means to said source and exhaust vent, means including an additional ball check in iiuid communication with the pump means and the valve means for alternately connecting the pump means to said valve means, filter means in fluid communication with the reservoir for cleaning the fluid medium as the uid medium is pumped from the reservoir by said pump means, and means controlled by said pump means and responsive to said low pressure iluid during the pumping operation for agitating the fluid medium yas the fluid medium is pumped from said reservoir thereby to prevent foreign matter from accumulating on the lter means.

References Cited in the file of this patent UNITED STATES PATENTS 2,422,916 Buchanan June 8, 1948 2,508,298 Saari May 16, 1950 2,579,670 Hjarpe Dec. 25, 1951 2,670,685 Coberly Mar. 2, 1954 2,858,767 Smith Nov. 4, 1958

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