US2948222A - Pump - Google Patents

Description

PUMP

Filed Aug. 4, 1958 2 Sheets-Sheet 1 l l2. o ',/'l' QG QM "g JNVENToR. 95 hv/zam s. Pine gg BY Aug. 9, 1960 w. s. PINE 2,948,222

PUMP

Filed Aug. 4, 1958 2 Sheets-Sheet 2 l INVENTOR.

lil/am .9 Pine United Starr-SA` Patent PUMP t William s. Pine, 163s E. 22nd sf., Los Angeles', Calif. Filed Aug. 4, 195s, ser.No.1ss,o63

1s claims. "(cl. 10a-4o) K This invention relates to a pump and is more particularly concerned with a two stage hydraulic pump.

, An object of the present invention -is to provide a hydrautlic pump for use in connection with hydraulic jacks Iand the like.

`An object of the present invention is to provide a manually operable pump of the character referred to which .is adapted to deliver -a large volume of Huid at low pressure until such time las the pressure reaches a predetermined point, whereupon the pump automatically converts :to deliver tiuid under higher pressure, but at a lesser volume.

Another object of the present invention is to provide a double acting pump'having a cylinder with a manually operable reciprocating piston engaged therein and adapted to deliver a large volume of fluid at low pressure when shifted in one direction and a lesser Vvolume of fluid at high pressure when shifted in the other direction.

It is an object of the present invention to provide a double acting pump of the character referred to including a novel iluid pressure responsive valve means adapted to automatically bleed or relieve the cylinder at the lower pressure side of the piston when the pressure in the apparatus in which the pump is engaged reaches a predeterm-ined amount.

Another object of the present invention is to provide a pump of the character referred yto having valve control means adapted to relieve pressure from lthe pump and the apparatus in which itis engaged and a safety pressure release means .adapted to relieve pressure from the pump and the apparatus when it exceeds a predetermined amount. Y'

It lis an object of -this invention to provide a pump of the character referred to which is easy and economical to manufacture and which is both highly etfectiveanddependable in operation.

. The various objects and features ofv my invention will be fully understood from the following detailed description of a typical preferred form and application of my vinvention throughout which description reference .is made to the accompanying in drawings, in which: v ,Y

Fig. l is a perspective view of ythe pump provided by the present invention.

Fig. 2 is a detached sectional view of my'new pump taken las indicated by line 2 2 on Fig. 1.

" Fig. 3 is a sectional viewv taken as indicated by line 3--3 6 6 on Fig. 5. fThe pump constructionthat I provide is a manually operated fluid pumpand is adapted -forus'e wherever it Yis desired to deliver or move Huid 'under pressure. The

. Patented Aug. 9,1960;

ICS.,

pump is Aparticularly adapted for use in connection with hydraulic jacks and the like.

The pump 'construction provided by the present invention, which construction is illustrated throughout the accompanying drawings, is a piston-type pump and is shown as including, ran elongate, block-like body A having a cylinder bore B therein, a piston C slidably engaged in the bore B, actuating means. D adapted to shift the piston C longitudinallyin the bore, inlet means E conducting fluid into the cylinder bore B, Avalve means F related to the cylinder bore and the inlet mean-s Eand Inormally preventing the iiow of fluid back or out through the inlet means E, Vvalvevmeans G carried bythe piston Cv adapted to conduct iluid from one side or end of the piston to the other, delivery means H adapted to conduct fluid from the bore and to connectnwith, a suitable jack, or the `like (not shown), and valve means I related to the, delivery meansH and preventing theflow ofr iluid back through the means H and into the bore.

The contsruction further includes a novel liuid presv sure actuating release means I related to the valve means F land adapted to open said valve Ymeans F when the pressure in the delivery means H reaches a predetermined amount, pressure release means K adapted to relieve pressure from the pump when it reaches a predetermined amount and manually operable bleed means L adapted to relieve all pressure from the unit and conduct fluid from the delivery means out through the inlet means.

The body A that I provide is an elongate, unitary block with flat top and bottom surfaces 10 and 11, flat, front and rear surfaces 12 and 13 and flat left and right ends 14 and l5.V The bore B is a simple, straight, cylindrical bore and enters the body A at the right end thereof and terminates in the body at a bottom 16; The bore B is closed by means of a suitable head 17 Isecured to the right end of the body. I

The head 17 isprovided with cylindrical Vboss 18 of limited longitudinal extent that slidably enters the outer end of the bore and through which a suitable opening 19 Ventends to slidably receive a rod 20 on the piston C, as

will hereinafter be described.

The bore B is provided with an annular, radially inwardly opening channel 21V in its outer portion, in which a suitable O-ring seal is arranged to seal with the boss 18'.

The opening 19 in the boss and head is provided with .an annular, radially inwardly opening channel 22 in which a suitable seal 23 is arranged to seal with the rod 20.

The piston C is a simple, disc-shaped unit having inner and outer ends 24 and 25 `and a cylindrical side Wall 26. The piston C is slidably engaged in the bore B and Iis provided about its side wall with a radially outwardly opening groove 27 in which a suitable seal 28 is arranged to seal with lthe Wall of the bore.

The piston rod 20 is a simple, elongate, cylindrical member formed integrally with the piston C and projects longitudinally from the outer end 25 of the piston and through the head 17. l'

The piston rod 20 is smaller Vin diametric extent than the bore and cooperates` therewith to establish an annular high pressure chamber X between the outer end 25 of the piston and the head 17 The actuating means D, adapted to shift the piston C longitudinally in the bore B, involves a bracket 30 fixed to the right end of the body A, above the head 17, an elongate, substantially vertically disposed handle 31 having its lower 4end engaged in a slot 32 provided in the outer terminal end ofthe Ypiston rod 20 and Yconnected therewith by a suitable pivot pin 33, a pair of links 34 extending between" the bracket 30 Yand the handle, at a point spaced above-the lower end thereof, and pivot-pins le# and 36 pivotally connecting the links with the bracket and the handle.

With the means D set forth above, it will be apparent that by shifting the handle 31 in the manner indicated by the arrows in the several iigures of the drawings, the piston C can be advantageously shifted in the bore B.

The inlet means E that I provide is shown as involving, an inlet port 37 entering the left end of the body, at a point spaced above the bore B, a cylindrical ow chamber 38 communicating with the inner end o-f the bore B and a vertical passage 39 establishing open communication between the port 3K7 and the chamber 3S.

In practice, a suitable inlet tube 40 is threadedly engaged in the inlet port 37, which tube extends to a reservoir or other suitable fluid supply (not shown),

The valve means F related to the bore B and the inlet means E is a simple check valve adapted to normally check the flow kof iluid from the bore, back through the inlet means.

In the form of the invention illustrated, the valve means F is shown as including, a cylindrical body having inner and outer ends 42 and 43, a cylidrical outer wall 44, a central, longitudinal ilow passage 45 and a socket 46 entering it from its outer end, concentric with the flow passage 45 and terminating within the body to establish an outwardly disposed valve seat 47. A spherical valve member or ball 48 is engaged in the socket 46 and is normally held in sealing engagement on the seat 47 by a compression spring 49 arranged within the socket and retained by a suitable snap ring 50i.

The body of the valve means F is slidably engaged in the body B to establish seated engagement on the bottom 16 of the bore and so that the flow passage 45 establishes open communication with the flow chamber 38. A suitable seal is carried by the valve -body about its outer wall 44 to seal with the bore B.

The piston C and the body of the valve means `F cooperate with the bore B to establish a lower pressure chamber Y.

The valve means G carried by the piston C is adapted to allow for the free flow of fluid from the lower pressure chamber Y occurring at the left of the piston to the high pressure chamber X occurring at the right of the piston and to check or prevent a reverse flow therebetween.

The valve means G is a simple check valve construction and is shown as involving, a socket 51 entering the inner end 24 of the piston and extending into the piston rod Ztl to terminate at a flat bottom 52, a plurality of radially disposed ports 53 in the piston rod, adjacent the 'outer end 25 of the piston and communicating with the socket adjacent the bottom thereof, an annular seat insert54 threadedly engaged in the open end of the socket, a ball 55 engaged in the socket inward of the seat insert and a compression spring 56 between the ball and the bottom of the socket to normally yieldingly maintain the ball in sealing engagement on the insert.

The delivery means H and valve means I that I provide is adapted to conduct and control the ow of fluid from the body B and is shown as including, an elongate discharge passage 57 entering the left end of the body, below the axis of the bore and continuing to the right to terminate adjacent the outer end portion of the bore, a socket 58 entering the bottom of the body to intersect the passage 57 and terminating at an upwardlyl inclined bottom 59, and a discharge port 60 continuing from the bottom of the socket and establishing open communi- 'cation with the bore B.

YIn practice, a suitable tube 61 is threadedly engaged Vin the open end of the passage 57 to conduct iluid delivered by the pump to a suitable jack, or the like (not shown).

With the construction thus far set fort-h, it will be apparent that when the pump is primed and is shifted in i the direction indicated by the arrow W, in Fig. 2 of the drawings, fluid is drawn into the chamber Y through the means E and past the valve means F and iluid in the chamber X is urged out through the means H and past the valve means I. It will be apparent that due to the limited effective cross-sectional area of the right hand end of the piston, the iuid thus discharged is under high i pressure as it leaves the bore.

Upon shifting the piston in the opposite direction, as indicated by the arrow W in AFig. 4 of the drawings, fluid in the chamber Y -is -displaced into the chamber X through the valve means G in the piston. -Due to the greater cross-sectional area of the chamber Y, more iluid is displaced from the chamber Y than 'can be accommodated by the chamber X, with the result that the excess fluid is urged outwardly through the means H andI.

Due to the relatively large effective cross-sectional area of the left hand end of the piston C, the uid discharged in the manner just mentioned is at relatively low pressure.

It will be apparent that upon continued operation of the pump, that is, continued reciprocation of the Vpiston C, fluid will continue to be delivered upon each stroke of the piston and until such time as pressures are generated in the delivery end of the construction which are such that the operator cannot exert suicientforces on the piston in the left direction to displace fluid from the lower pressure chamber Y.

In order to prevent the pump from locking or becoming overloaded so that it cannot be operated as set forth above, l provide the iluid pressure actuated release means I, which means is adapted to put the valve means F out of service when the fluid pressure in the discharge end of the construction reaches a predetermined amount.

The means .I that I provide is shown as including a hydraulic ram unit 65 engaged in a socket 66 entering the left end of the body A and a fluid passage 67 extending between the discharge passage and the socket 66 and conducting fluid from the passage to the unit in the socket.

r-lhe socket 66 is in axial alignment with the bore B in the body and terminates at a flat bottom 68. The dow chamber '38 establishes opening 'communication with the bottom of the socket.

The unit 65 includes a cylinder sleeve 69 having an open inner end and a closed outer end. The sleeve is slidably engaged in the socket. A piston 70 is slidably engaged in the socket and is provided with an elongate stem 71 which projects inwardly from the piston through the flow chamber 38' and into the ow passage 45 of the valve F. p

The sleeve 69 seats against a suitable outwardly disposed shoulder provided in the socket intermediate its ends and is maintained engaged in the socket by means of a suitable snap ring-type retaining means, as clearly illustrated in the drawings.

The sleeve 69 is provided with an annular fluid handling 'groove 72 about its exterior to register with the uid passage 67, and a plurality of ports 73 establishing open communication between the said groove 72 and the interior of the sleeve7 inward of the piston 70 therein.

In practice, the sleeve 69 is provided with a second annular kgroove spaced outwardly of the groove 72 Vand in which a suitable sealing ring 69 is engaged to seal between the sleeve and the wall of the socket.

The unit 65 further includes a suitable flanged stem and spring guide 74 seated on the bottom of the socket to slidably receive the stern 71 and to carry a compression spring 75, which spring is adapted to occur between the ilange on the guide yand the piston 70 and to normatlly yieldingly urge the piston and the stem to the left.

In operation, the Vmeans I is normally in the position illustrated in Fig. 2 Vof the drawings. Y

When the pressure in-the outlet end of the 'construction becomes excessive, the unit 65 ofthe means J is actuated so that the stem is shifted through the flow passage 45 of the means F and engages and urges the ball 48 thereof out of seated engagement, as 'clearly illustrated in Fig. 5 of the drawings.

With the valve means F rendered ineffective, as set forth above, when the piston C is shifted to the left, certain'of the fluid in the chamber Y is displaced to the chamber X through the valve means G and the remainder is bled back through the inlet means E.

With the above relationship of parts and mode of operation, it will be apparent that the pump is automatically converted from a low pressure double acting piston pump into a single action high pressure piston pump.

The pressure release means KV that I provide is a safety means adapted to relieve pressure from the pumpwhen the pressures exceeding a predetermined safety factor are reached.V f

The means K is shown as involving a socket 80 entering the front side 12 of the body A and terminating at an inwardly convergent bottom 81, which bottom establishes a valve seat, a pressure release passage 82 extending between the socket and the vertical passage 39 of the means F, a pressure conducting passage 83 extending from the passage 57 of the means H and establishing openv communication with the socket 80 at the bottom thereof, a valve member 84 in the socket, a suitable plug 85 closing the open end of the socket and a compression spring 86 between the plug and the valve member and adapted to normally yieldingly urge the valve member in seated sealing engagement on the bottom of the socket.

With the above construction it will be apparent that when pressures in the delivery end of the pump reach a predetermined point, Huid is bled from the means H through themeans K and back into the means E, with the result that the pressure in the construction is relieved.

The manually operable bleed means L that I provide,

which means is adapted to relieve all the pressure from the construction, as when it is desired to drain the fluid from the equipment to which the pump is related, is shown as including an elongate, vertically disposed bore 90 entering the top of the body and terminating at a flat bottom, a port 91 extending between the bore 90 and the ow chamber 38, a socket entering the bottom.

of the body A in axial alignment with the bore 90 and establishing a chamber 92, `a plug 93 .closing the-bottom end of the chamber, a port 94 extending between the passage 57 of the means H and the chamber 92, a downwardly convergent or tapered port 95 extending between the bottom of the bore 90 and the chamber 92.', and an elongate, downwardly convergent or tapered needle valve 96 engaged in the port 95. The valve`96 is provided with an upwardly projecting stem 97 threadedly engaged in the upper portion of the bore 90 and projecting from the top of the body A and a handle wheel 98 on the outer end of the stem.

In practice, the valve 96 carries a suitable seal 99 to the accompanying drawings, it will be apparent that I have-provided a novel, highly effective and dependable pump construction and a construction that is both easy and economical to manufacture.

, Having described only a typical preferred form and application of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any modifications or variations Y S that may appear Vto those skilled in the artgan'd fall within the scope ofthe following claims.

YHaving described my invention, I claim:

1. A pump of the character referred to including,V a body having a cylinder bore therein terminating at a bottom, ahead Aclosing the open end of the bore, a porttd piston slidably engaged in the bore and having an elongate rod projecting therefrom and through the head, operating means coupled with the rod and operable to reciproacte the piston in the bore, an inlet duct'V cornmunicating Awith the bottom of the bore, a check valve checking the ow of uid outwardly through the inlet duct, a check valve carried by said ported piston and adaptedto allow for the flow ofuid through the' piston towards the open end of the bore, a delivery duct communicating with the bore adjacent 'the open endA thereof, a check valve related to said delivery duct to check the flow of fluid from said ductinto the bore and a uid pressure actuated means related tol said first mentioned check valve and operable in response vto the uid pressure in the"delivery duct to open said rst mentioned Vcheck valve and render the same ineffective.

2. A pump of the character referred to including,l a body having a' cylinder bore therein terminating at a bottom, a head closing the open end of the'bo're, a ported piston slidably engaged in Ythe bore and having an elongate rod projecting therefrom and through the head, operating means coupled with the rod'and operable to reciprocate the piston in the bore, an inletduct communicating with the bottom of the bore, a check valve checking the flow of fluid outwardly through the inlet duct, a check valve carried by said ported piston and adapted to allow for the ow of fluid through the piston towards the open end Vofthe bore, a delivery duct communicating with the bore adjacent the open end thereof, a check valve related to said delivery duct to check the ow of fluid from saidduct into the bore and a' spring loaded 'fluid pressure actuated means relatedl to said first mentioned check valve nand operable in response to predetermined uid pressure lin the delivery duct to open said vfirst' mentioned check valve and render the same ineffective.

3. A pump of the character referred to including, a body'having a cylinder bore therein terminating at a bottom, a head closing 'the open end of the bore and having an elongate rod projecting therefrom and through the head, operating means coupled with therod and operable to reciprocate the piston in the' bore, an inlet duct communicating with thebottom of the bore, a check valve having a shiftable valve member and check` ing the flow of iluid outwardly through the inlet duct,

a check valve carried by said ported piston and adapted to allow for the ow of fluid through the piston towards the open end of theV bore, a delivery duct communicating with the bore adjacent the open end'thereof,V a check valverelated to said delivery duct to check the flow of fluid from said duct into the bore and a iluid pressure actuating means related to said l'rst mentioned check valve and having a shiftable member engaging said shiftable valve member, saidmeans being operable in response to the uid pressure in the delivery duct to open said rst mentioned check valve and `render the same ineffective. V

4. A pump of the character referred to including, a body having a Ycylinder bore therein terminating at a bottom, a head closing the open end of the bore, a ported piston slidably engaged in the bore and having an elongate rod projecting therefrom and through the head, operating means coupled with the rod and operable to reciprocate the piston in the bore, an inlet duct communicating with the bottom of the bore, a check valve having a shiftable valve member and checking the ow of uid outwardly through the inlet duct, a check valve carried by said ported 'pistonand adapted to allow for the flowof fluid through the piston towards the open end of the bore, a delivery duct communicating with the bore adjacent the open end thereof, 'a check valve related to said delivery duct to check the flow of uid from said duct into tthe bore and a spring loaded fluid pressure actuated means related to said first mentioned check valve and having `a shiftable member engaging said `shiftable valve member, said means being operable in response to predetermined uid pressure in the delivery duct to open said first mentioned check valve and render the same ineffective.

5. A pump of the `character referred to including, a body having a cylinder bore therein terminating at a bottom, a head closing the open end of the bore, a ported piston slidably engaged in the bore and having an elongate rod prijecting therefrom and through the head, operating means Coupled with the rod and operable to reciprocate the piston in the bore, an inlet duct communicating -with the bottom of the bore, a spring loaded ball check valve related to said inlet duct and normally checking the flow of uid from the bore out through the inlet duct, a check valve carried by the ported piston and adapted to allow for the flow ,of uid through the piston towards the open end of the bore, a delivery duct communicating with the bore adjacent the open `end thereof, a check valve related to said delivery duct to check the ow of fluid from said duct into the bore and a spring loaded fluid pressure actuated means related to said ball check valve and having a shiftable element to engage the ball, a duct establishing opening communication between the delivery duct and said actuating means, said actuating means being operable upon the establishment of a predetermined pressure in the delivery duct to urge the ball out of seated engagement and thereby render the ball check valve inoperative.

6. A pump of the character referred to including, a body having a cylinder bore therein terminating at a bottom, a head closing t-he open end of the bore, a ported piston slidably engaged in the bore and having an elongate rod projecting therefrom and through the head, operating means coupled with the rod and operable to reciprocate the piston in the bore, an inlet duct communication with the bottom of the bore, a spring loaded ball check valve in the bottom of the bore and normally checking the ow of uid from the bore and out through the inlet duct, a check valve carried by the ported piston and adapted to allow f or the flow of fluid through the piston towards the open end of the bore, a delivery duct communicating with the bore adjacent the open end thereof, a check valve related to said delivery duct to check the flow of fluid from said duct into the bore and a spring loaded iluid pressure actuated means related to said ball check valve and having a shiftable element to engage the ball, a duct establishing open communication between the delivery duct and said actuating means, said actuating means being operable upon the establishment of a predetermined pressure in the delivery duct to urge the ball out of seated engagement and Athereby render the ball check valve inoperative.

7. A pump of the character referred to including, a body having a cylinder bore therein terminating at a bottom, a head closing the open end of the bore, a ported piston slidably engaged in the bore and `having an `elongate rod projecting therefrom and through the head,

operating means coupled with the bore and operable to reciprocate the piston in the bore, an inlet duct in the body communicating with the bottom of the bore and connected with a supply pipe, a spring loaded ball check valve in the bottom of the bore and normally checking the ow of iluid from the bore out through the inlet duct,

a check valve carried by the ported piston and adapted to allow for the llow of fluid through the piston towards the open end of the bore, a delivery duct in the body communicating with the bore adjacent the open end @thereof and connected with a delivery pipe, a check valve related to said delivery duct to check the flow of fluid from said duct into the bore and a spring loaded fluid pressure actuated meansY carried by the body to occur adjacent the said ball check valve yand having a shiftable element to engage the ball, a duct Vestablishing open communication between the delivery duct and said actuating means, said actuating means being operable upon the establishment of a predetermined pressure in the delivery duct to urge the ball out of seated engagement and thereby render the ball check valve inoperative.

8. A pump of the character referred to including, a body having a ,cylinder bore therein terminating at a bottom, a head closing the open end of the bore, a ported piston slidably engaged in the bore and having anelongate rod projecting therefrom and through the head, manually operated operating means kcoupled with the rod and operable to reciprocate the piston in the bore, an inlet duct in the body communicating with the bottom of the bore and'connected with a supply pipe, a spring loaded ball check valve in the bottom of the bore and normally checking the ilow of fluid fromv the bore out through the inlet duct, a spring loaded check vvalve carried by the ported piston and adapted to allow for the flow of fluid through the piston towards the open end of the bore, a delivery duct in the body communieating with the bore adjacent the open end thereof, and connected with a delivery pipe, a spring loaded check valve in said delivery duct to check the flow of fluid from said duct into the bore and a spring loaded fluid pressure actuated means carried by the body to occur adjacent the said ball check valve and having a shiftable element to engage the ball, a duct inthe body establishing opening communication between the delivery duct and said actuating means, said actuating means being operable upon the establishment of a predetermined pressure in the delivery duct to urge the ball out of seated engagement and thereby render the ball check valve inoperative.'

9. A pump of the character referred to including, a body having a cylinder bore therein terminating at a bottom, ahead closing the open endl of the bore, a ported piston slidably engaged in the bore and having a elongate rod projecting therefrom and through the head, operating means coupled with the rod and operable to reciprocate the piston in the bore, an inlet duct communicating with the bottom of the bore, a check valve checking the llow of fluid outwardly through the inlet duct, a check valve carried by said ported piston and adapted to allow Vfor the flow of fluid through the piston towards the open end of the bore, a delivery duct communicating with the bore adjacent the open end thereof, a check valve related to said delivery duct to check the flo-W of fluid from said duct into the bore, a fluid pressure actuated means related to said first mentioned check valve and operable in response to the fluid pressure in the delivery duct to open said first mentioned check valve and render the same ineffective and pressure release means including a flow passage between'said inlet and delivery ducts and a spring loaded relief valve in said flow passage.

l0. A pump of the character referred to'ncluding, a body having a cylinder bore therein terminating at a bottom, a head closing the open end of the bore, a

ported piston slidably engaged in the bore and having van elongate rod projecting therefrom and through the head, operating means coupled with the ro d and oper- Vable to reciprocate the piston in the bore, an inlet duct piston towards the open end of the bore, a-delivery duct communicating with the bore adjacent the open end thereof, a check valve related to said delivery duct to check the flow of fluid fromV said duct into the bore, a fluid pressure aetuatedmeans related to said rst mentioned check valve and operable in', response to the fluid pressure in thevdelivery duct to open said rst mentioned check valve and render'the same'ineffect'ive and bleed ymeans including a fluid'passagebetween said inlet and delivery ducts Yand a manually operable valve related to said uid passage to control the flow of fluid from the delivery duct intosaid inlet duct. l

1l. A pump of the character referred to including, a body having a cylinder bore therein terminating at a bottom, a head closing the open end of the bore, a ported piston slidably engaged in the bore and having an elongate rod projecting therefrom and through the head, operating means coupled #with the rod and operable to reciprocate the piston in the bore, an inlet duct communicating with the bottom of the bore, a check valve checking the ow of huid outwardly through the inlet duct, a check valve carried by said ported piston and adapted to allow for the ow of iluid through the piston towards the open end of the bore, a delivery duct communicating with the bore -adjacent the open end thereof, a check valve related to said delivery duct to check the iiow of uid from said cut into the bore, a uid pressure actuated the same ineffective, pressure release means including a flow passage -between said inlet and delivery ducts and a spring loaded relief valve in said ow passage and bleed means including a iluid pass-age between said inlet and delivery ducts and a manually operable valve related to said iiuid passage to control the iiow of fluid lfrom the delivery duct into said inlet duct.

l2. A pump of the character referred to including, a body having a cylinder bore therein terminating at a bottom, a head closing the open end of the bore, a ported piston slidably engaged in the bore tand having an elo-ngate rod projecting therefrom and through the head, operating means coupled =with the rod and operable to reciprocate the piston in the bore, an inlet duct communicating with the bottom of the bore, a spring loaded ball check valve related to said inlet duct and normally checking the flow of uid from the bore out through the inlet duct, a check valve carried by the ported piston and adapted to allow for the flow of fluid through the piston toward-s the open end of the bore, a delivery duct communicating with the bore adjacent the open end thereof, a check valve related to said -delivery duct to check the flow of uid from said duct into the bore and a spring loaded uid pressure actuated means related to said ball check valve and having a shiftfable element to engage the ball, a duct establishing opening communication between the ydelivery -duct and said actuating means, said actuating means being operable upon the establishment of a predetermined pressure in the delivery duct to urge the ball out of seated engagement and thereby render the ball check valve inoperative, and pressure release means including a ow passage between said inlet and delivery ducts and a spring loaded relief valve in said how passage.

13. A pump of the character referred to including, a body having a cylinder bore therein terminating at a bottom, a head closing the open end of the bore, a ported piston-slidably engaged in the bore and having an elongate rod projecting therefrom and through the head, operating means coupled with the rod and operable to reciprocate the piston in the bore, an inlet duct communicating with the bottom of the bore, a spring loaded ball check valve related to said inlet duct and normally checking the How of uid from the bore outthrough the inlet duct, a check valve carried by the ported piston and adapted to allow for the ow of fluid through the piston towards the open end of the bore, a delivery duct communicating with the bore adjacent the open end thereof, a check valve related to said delivery duct to check the how of fluid from said duct in the bore and a spring loaded uid pressure actuated means related to said ball check valveandliavinga shiftable lelement toengage the ball, a duct establishing opening communication between the delivery duct and said actuatingmeans, said actuating means being operable upon vthe establishment of a predetermined pressure in the delivery duct to urge the ball out of seated engagement and thereby render the ball check valve inoperative, land bleed means including a iiuid passage between said inlet and delivery ducts and -a manually operable valve related to said iluid passage to control the ilow of uid from the delivery duct into said inlet duct.

14. A pump of the character referred to including, a body having a cylinder bore therein terminating at a bottom, a head closing the open end of the bore, a ported piston slidably engaged in the bore and having an elongate rod projecting therefrom and through the head, operating means coupled with the rod and operable to reciprocate the piston Iin the bore, an inlet duct communicating with the bottom of the bore, a -spring loaded ball check valve related to said inlet duct and normally checking the flo-W of fluid from the bore out through the inlet duct, a check valve carried by the ported piston and adapted to allow for the ilow of uid through the piston towards the open end of the bore, a delivery duct communicating with lthe bore adjacent the open end thereof, a check valve related to said delivery duct to check the flow of fluid from said duct into the bore and a spring loaded fluid pressure actuated means related to said ball check valve and having a shiftable element to engage the ball, a duct establishing opening communication between the delivery duct and said actuating means, said actuating means being operable upon the establishment of a predetermined pressure in the delivery duct to urge the ball out of seated engagement and thereby render the .ball check valve inoperative, pressure release means including a iiow passage between said inlet and delivery ducts and a spring loaded relief valve in said flow passage, and bleed means including a iluid passage between said inlet and delivery ducts and a manually operable valve related .to said fluid passage to control the flow of uid from the delivery duct into said inlet duct.

l5. A pump of the character referred to including, a body having a cylinder bore therein terminating at a bottom, a head closing the open end of the bore, a ported piston slidably engaged in the bore and having an elongate rod projecting therefrom and through the head, manually operated operating means coupled with the rod and operable to reciprocate the piston in the bore, an inlet duct inthe body communicating with the bottom of the bore and'connected with a supply pipe, a spring loaded ball check valve in the bottom of the bore and normally checking the ow of Huid from the bore out through the inlet duct, a spring loaded check valve carried by the ported piston 'and adapted to allow for the flow of Huid through the piston towards the open end of the bore, a delivery duct in the body communicating with the bore adjacent the open end thereof, and connected with a Vdelivery pipe, a spring 1loaded check valve in said delivery duct to check the ow of uid from said duct into the bore and a spring loaded uid pressure actuated means carried by the body to occur adjacent the said ball check valve and having a shit-table element to eng-age the ball, a duct in the body establishing opening communication between the delivery duct and said actuating means, said actuating means being operable upon the establishment of a predetermined pressure in the delivery duct to urge the ball out of seated engagement and thereby render the ball check Valve inoperative, pressure release means including a ow passage between said inlet and delivery ducts and a spring loaded relief valve in said flow passage, and bleed means including a duid passage between said inlet and delivery ducts and a manually operable valve related to said fluid passage to control the flow of uid from the delivery duct into saidinlet duct.

(References on following page) UNITED STATES PATENTS Hanson etal. Aug. 26, 1930 Groves Mar. 27, 1945 Kehle July 23, 1946 Page May 25, 1948 Haumeuson Aug, 24, 1948 Bom Jan. 21, 1958 12 FOREIGN PATENTS 354,726 Italy Dec. 6, 1937 731,643 Germany Feb. 12, 1943 1,075,780 France Apr. 14, 1954 OTHER REFERENCES German application 1,007,715, dated May 9, 1957 (KL 5C-10/O1).

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