US2452482A - Hydraulic jack - Google Patents

Description

Oct- 26, 1948. J. J. MUELLER 2,452,482

HYDRAULIC JACK INVENTOR.

Jza .JZ/Q2@ MMM/M Oct. 26, 1948. I J. J. Mur-:LLER 2,452,482

' HYDRAULIC JACK Filed May 15, 1944 2 Sheets-Sheet 2 e 74 l `W @0 .56

j@ j 10 ad y Patented Qct. 26, 1948 HYDRAULIC JACK Joseph J. Mueller, St. Joseph, Mich., assigner to Auto Specialties Manufacturing Company, St. Joseph, Mich., a corporation of Michigan Application May 13, 1944, Serial No. 535,436

12 Claims.

This invention relates to hydraulically'operated pushing and pulling devices, and more particularly to hydraulic jacks for lifting relatively heavy loads.

Among the objects of the present invention are to provide an hydraulic jack that is composed of a minimum number of parts, each of simple construction, the parts being designed to be capable of economical and ready manufacture and easily assemblable into an operable hydraulically operated jack structure.

Further objects of the invention are to provide an hydraulic jack including `a base suitably formed to provide a ram cylinder and a surrounding reservoir and provided with but one additional bore extending to the exterior of the base for the purpose of receiving a combined high pressure pump cylinder and release valve, the jack including mechanism for reciprocating the piston of the pump in the pump cylinder and for longitudinally sliding, without turning, the high pressure pump cylinder for the purpose of closing the release valve upon its seat, the closing mechanism being constructed and arranged so that upon release movement thereof the high pressure pump cylinder will be released for shiftable movement in a reverse direction, whereby the pressure in the ram cylinder will eiect an unseating movement of the release valve to relieve the liquid from the ram cylinder back into the reservoir; to provide a simple and economical manner of forming a combined high pressure pump cylinder with its reciprocable piston, together with a valve cage unit and release valve operable as a unit and shiftable without turning, parallel to its own longitudinal axis and wherein the piston is capable of easy pivotal connection to the piston reciprocating mechanism, and wherein the cylinder is capable of easy connection to mechanism pivoted on the base for sliding the cylinder, the Valve cage and therelease valve relatively to a valve seat formed in the base for controlling the relief of the ram cylinder; to provide these and other objects of invention, as will be apparent from the following specication when taken in connection with the accompanying drawings, wherein:

Figure l is a front elevation of one form of my improved jack;

Figure 2 is a side elevation thereof;

Figure 3 is a plan view thereof;

Figure 4 is a section on the line l-d of Figure 2;

Figure 5 is a perspective View of the high pressure pump cylinder piston, ball valve cage unit,

2 and release valve, with the connection to the shifting vmechanism therefor;

Figure 6 is a detail fragmentary sectional view showing the Valve cage and release 'valve 'shifted te 'closed position on its seat; and A Figure '1 is a section taken on the 'line i--l of Figure 6.

Referring new to the drawings in detail., the jack preferably comprises fa 'base 2 'herein shown as formed with a well '4 having up'sta'r'rd'i'ng, i'nternally threaded Walls 'G cohceiit'rically sui"- roundingr the Well 'and 'adapted to recive the lower, externally threaded ends of the lc ylind'er 8. In addition, the ba'se 2 is providedwth 'a concentri'cally surrounding sh'uld'ered and countersunk portionl ID which recfvs A'ad'l'li tional sleeve l2 "fc'rming the liquid rese'ryclr r4 between it and the cylinder 8. The j'linetin between the shoulder it and the lower portion of the sleeve I2 is' a press t 'which is in addition wel-deu 'so as to iorm a very secure union. I

A headr I6 'O'irnS a Welded press fit jllctioh r"i8 with the outer 'Sleeve I2 "and irl addition the inner Wall of this head is threaded as at 2li to receive the threaded external walls 'of 'the ram cylinder 8. The 'inner annular surface 2v2 of 'the head is coredout or cut 'out as "at y22 to provide an nil 'chamber and the usual type or vplanung and the usual threaded washer 2E` is thre'fdedly connected to the top of the head IG t'o hold the packing in position fso 'that' the ram '28 may reciprocate through the packing withl'it'leaka'lge of oil thereby. `The upper fend of the ram "is pro-v vided with the load S'libprt 30A, and the 16u/'erelid of the ram is provided with the usual sealing ring 32 formed of leather yer other flexible material 'and held inpla'c'e by '-r'neans of the usual fastening member 34, as `i's 'well known in the art.

The base is 'prv'ided with one additional bring or 'opening which 'extends to 'the eiterior of the base, and this comprises 'the bore 3'5 which 'receives 'the high pressure pump cylinder, the piston reciprocable therein, the unitary ball valve cage and release valve. yNo `other ccnduit 'formed in the base eXten'ds to the eXteri'I" of the base, thereby keeping leakage 'to a min-imum Ihe basal ycasting is provided 'with a conduit 3'8 which connects with 'the 'well d.. passage 38 is formed in the base l2 'at such an angulfarity that its projection passes above the upper surfaces 'oi the base so that when the ram cylinder 8 and reservoir cylinder wall l2 are removed from the base, the 'conduit 38 may be bored fbir'l the upper face ci the base. The 'outer end of this conduit connects with another short conduit 48, the center inder, when the release valve is raised from its'Y seat. It will thus be seen that the bore 44 and the valve seat 43 all connect with the bottom of the bore36. y .Y

The basal casting at one side of the cylinder` l2 is provided with an upstanding projection 46 about the bore 36, and this projection-45 is provided with an opening 50 to receive a pivotal pin 52 as hereinafter described. v

The high pressure pump cylinder is formed in a novel manner. It is formed of a short length of steel tubing, preferablyformed by cutting a long steel tube into requisite lengths to correspond with the length of the high pressure pump cylinder desired. The steel'tubing is given a high finish interiorly, preferably before it is cut into lengths, so that no further interior finish need be imparted to the high pressure pump cylinder, which'will reciprocatingly receive the high pressure pump piston without further finishing operation. Thus the high pressure pump cylinder 54 is formed in an appropriate length of steel tubing, as shown in Figure 5. It is round in cross section'and receives, with a tight lit at its upper end, an annular ringl or head 56 which ring is closed at both ends, one of the ends receiving a threaded nut 58 to press a packing 6| Within the annulus, tightly against the piston 62 which is adapted to-reciprocate throughv the sleeve-like cylinder 54 and head 56. The head is preferably provided with two outstanding diametrically opposed studs 68, and this headis adapted to make a tight wedgingor welded fit with `the upper end of theouter'surface. oi" the sleeve 54 while reciprocatingly receiving the piston 62 therethrough. The outer end ofthe piston is provided with a slot' 64 to receive in the usual-manner theconnecting pin 66 connected bya yoke 68 to thek handle which receives the reciprocable handle bar 12. rThe inner end of this handle socket A'lll is pivoted as at 14 to 1an outstanding ear 'I6 formed on the sleeve I2. AThe inner end of the handle bar 12 is notchedas at 78 to engage the valve shifting mechanism,'as hereinafter set forth.y

The lower partof the piston is provided with the usual sealing washer 88, 'as is well known in the art, the same being held in position by means of the screw 82.

s Theextreme lower end 'of the high pressure pump cylinder 54 makes a tightt with a countersunk shoulder 86 formed ona unitary ball valve cage, the details of which are 'shown more clearly in Figure 6; This ball valve cage comprises a ported member or ported means having internal valves governing passages which are adapted to connect the passage 44 leading to the reservoir with the piston chamber within the cylinder 54 so that when the piston moves outwardly, liquid will be drawn through the port 44 into the port 88, thence into port 90,' past ball valve 92, into the piston chamber 94. Upon reverse movement of .the piston, liquid will be forced through the port 96 past the ball valve 98, through port |88, through port |83, into port 40, thence through passage 38 to the ram cylinder. The balls are held close to their seat by means of inserted wires |82.

The lower end of the ball valve cage is preferably provided as a separate hard metal cap or valve member |0| having a central port |03 therethrough and provided with abruptly shaped conical walls |84 of such angularity as to seat upon the annular shouldered valve seat 43 with a minimum annular contact, whereby a tighter seating of the valve upon the valve seat is provided, and thus closing any direct connection between the ports 38, 48 and dll while permittingliquid to flow through the ball valve cage, through the reservoir to the pump cylinder chamber, to the ram cylinder. This member |ll| to this end isprovided with a countersunk shoulder the upper portion of which iits within a recess countersunk within the end of the ball valve cage and the i'lt is such that the upper face H5 of this release valve |8| is suiiiciently close to ball 98 to hold it upon its seat. In addition, the ballvalve cage at the opening at which the ball valve 92 operates, is peened in as shown at |87 to hold the ball in position relative to its seat. Means is provided for manually shifting the combined structure'shown in Figure 5 which cornprises the high pressure pump cylinder which rigidly carries the ball valve cage 87 and the release valve I 04 therewith, to force the release valve |04 to its seat 43. This means comprises mechanism which, without turning or permitting the turning of the high pressure pump cylinder, shifts this high pressure pump cylinder, ball valve cage, and release valve in a direction parallel to the longitudinal axis of this structure so as positively to draw the release valve to its seat. Inaddition the structure is arranged so that upon a release movement, the liquid pressure which has been built up in the ram cylinder during the raising of the ram, will automatically force -this structure, which includes the release valve, from its seat and thereby relieve the ram cylinder pressure so that liquid will flow from the ram cylinder at well 4 through the ports 38 and 49 through the open release valve, through port 44, back to thereservoir. This means comprises a linkage mechanism which includes a type of bell cranklever |86 pivoted about the iixed pivot 52. kThis lever` includes an arm |88 internally threaded at i8 to receive the screw i i2, the screw having at its inner end a rounded surface ||3 and at its outer end the cross bars H6 by which it may be turned when contacted by the notch I8 in the inner end of thehandle 12. In addition the other end of the bell crank |06 includes the forks ||4,there being two of them which are pivoted as at ||7 and ||8 to a pair of links |2 and |22 which in turn are pivoted to the opposed, diametrical pins 68 outstanding from the head 56. The arrangement is such that when the outer ends |16 of the screw |2 are turned in the correct direction, the bell crank-will shift about its fived pivot wherebyv to draw down upon the links |20` and cause the head 56 to be drawn down whereby to likewsie shift the high pressure pump cylinder 54 downwardly, ,thereby shifting the unitary ball valve cage and release valve formed now integrally with the lower portion of the pump cylinder, downwardly, Ato close the release valve upon its valve seat 43. When the screw |52 is turned in the reverse direction it will release this drawing down action so that the pressure built up in the conduit 38 and ,40 will now force the unitary structure 54, 8l, and |84 outwardly away from the seat t'o relieve the ram Icylinder pressure. It will be noted that this movement of the yhigh pressure pump cylinder is independent of any re'ciprooable action of the v'piston 62 in the pump cylinder and is therefore independent of any re'ciproc'able position of the piston in the pump cylinder. y

By 'the foregoing mechanism I .provide a very simple, economical, rugged jack, which is composed of few parts, easily manufactured, easily and quickly assembled into a 'completely operative 'structure wherein the release valve may be opened or closed from a point readily accessible on the jack and without any involved interrelation with Ithe reciprocable piston, and particularly by means of the present construction [I have reduced to a minimum number of .parts the mechanism for shifting the high pressure pump cylinder relatively to the base of the ack for accomplishing the shifting of the release valve onto its seat and conversely for permitting 'the pressure in the ram cylinder to shift the release valve from its seat automatically, In addition, it will be seen that I have provided a simple means vfor manufacturing a high pressure pump cylirrder from steel tubing, completely finished within so as to receive the high pressure pump piston without further finishing operation, and I have provided means whereby the jack may be readily taken apart to repair any Adefective operation 'ci the ball valves. This repair work is accomplished in a very simple manner by disconnecting the operating mechanism from the high pressure pump piston, removing it and the cylinder from the base, so that the ball valve cage and release valve are exposed. If desired, 'the ball valve cage is readily removed from the lower end of the high pressure pump cylinder for repair or replacement.

Obviously the invention is not limited to the specific details of construction disclosed herein but is capable of other modifications and changes without departing from the spirit and 'scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In an hydraulic jack having a base provided with a bore, said base having thereon a Tram cylinder, a liquid reservoir 'associated with said base, a pump cylinder comprising a sleeve of uniform cross section having a smooth exterior 'slidable in said bore, a ram for the ram cylinder, a piston reciprocable in the pump `f'zylin'd'er sleeve, yconduit means in the base interconnecting the reservoir, the pump cylinder and the ram cylinder, ported and valved means carried by said pump cylinder sleeve for transferring liquid through said conduit means from the re'servoii1 t'o the pump cylinder, and from the pump cylinder 'to the ram cylinder upon -reciprocation of said piston, release valve means including a valve seat formed in the base in association with `certain oi said ports and including a release valve carried by said ported and valved means and shiftable with said cylinder sleeve and ported and valved means, and means connected with said 'cylinder and operative from a point exteriorly of said base, vfor sliding said sleeve in a direction parallel to its longitudinal axis While holding said sleeve from rotation for closing said release valve upon its seat.

2. In an hydraulic jack, a base having a ram cylinder, a liquidreservoir and 'a pump vcylir-ider bore, a ram in the ram cylinder and a pump cylinder slidable in said bore and a reciprocable piston in the pump "cylinder, yconduit means interconnecting the reservoir, the pump cylinder and the ram cylinder, ported and valved means carried by said pump cylinder for transferring liquid through said conduit means from the reservoir tothe pum-p cylinder, and from the pump cylinder to the ram cylinder upon reciprocation of said piston, Arelease valve means including a valve seat formed -in the base in association with certain of said ports and including a release valve carried by said ported and valved means and slidable in said bore with said cylinder, and linkage meanspivoted to said base and to said pump cylinder' and operable from the exterior of said base for sliding said cylinder longitudinally to close said release valve upon its seat.

3. In an hydraulic jack having a base provided with a bore, a ram cylinder, a liquid reservoir associated with said base, a pump cylinder slidable in said bore, a ram in the ram cylinder and a reciprocable piston in the pump cylinder, conduit means interconnecting the reservoir, the pump cylinder and the ram cylinder, ported and valved means carried by said .pump cylinder for transferring liquid through said conduit means from the reservoir to the pump cylinder, and from the pump cylinder to the ram cylinder upon reciprocation of said piston, release valve means including a valve seat formed in the base in association with certain of said ports and including a release valve carried by said ported and valved means and slidable with said pump cylinder, an annular head mounted Von the outer part of said pump cylinder 'and through which said piston is adapted to reciprocate, and linkage means pivotally mounted on 'said base and connected with said head and operable exteriorly of said base for sliding said pump cylinder parallel to its longitudinal axis for closing said release valve upon its seat.

4, In-an yhydraulic jack having a ram cylinder, a liquid reservoir and a pump cylinder in the form of an elongated sleeve, a ram in the ram cylinder and a reciprocable piston in the pum-p cylinder, conduit means interconnecting the reservoir, the pump cylinder and the ram cylinder, ported and valved means carried by said pump cylinder sleeve for transferring liquid through said conduit means from the reservoir to the pump cylinder, and from the pump 'cylinder to the ram cylinder upon reciprocation `of said piston, release valve means including a valve seat formed in the base in association with certain of Isaid ports said by-pass valve means including a valve carried by said ported and valved means and shiitable with said pump cylinder sleeve, and an annular head exteriorly mounted 'on the opposite end vof said sleeve and through which said piston is adapted to reciprocate as Isaid piston recipro'cates in said pump cylinder sleeve, a pis-ton actuator pivotally mounted on said jack and connected to the outer end of said piston, and means mounted on said jack `and connected to said head for shifting said pump lcylinder sleeve in a direction parallel to its longitudinal axis while holding said pump cylinde-r sleeve from rotation for closing said release valve upon itsseat.

5. An lhydraulic Ajack comprising a base having liquid passages therein, means providing a ram cylinder and a liquid reservoir for said base, a ram in said ram "cylinder, said base having a bore formed with an Venlargement at its mouth in the upper part 'of the base, a pump cylinder in the form of an .elongated sleeve mounted in said bore and projecting beyond said base, packing means in the enlargement of said bore eX- teriorly of said sleeve, means connected with the base around said bore enlargement for holding said packing means compressed against said cylindrical pump sleeve while permitting movement ci said cylindrical pump sleeve parallel to its longitudinal axis, a pump piston `reciprocal in said pump cylinder sleeve, said base at the central portion of the bottom of said bore being provided with a valve seat in association with certainv of said liquid passages of said base, a ported valve cage disposed in said bore and located between said valve seat and the end of said pump sleeve, the lower portion of said cage being formed as a release valve to close upon said valve seat, an' annular head connected to the outer end of said pump cylinder sleeve and through which said pump piston is adapted to reciprocate as it reciprocates in said cylindrical pump sleeve, packing means in said head about said piston, means for compressing said packing means between said head and said piston, a piston actuator pivotally mounted on said jack and pivotally connected to the outer end of said piston, and linkage means pivotally connected with said head and pivotally iounted on said jack for shifting said pump cylinder sleeve in a direction parallel to its longitudinal axis while holding it from turning.

6. A high pressure pump cylinder and release valve assembly for hydraulic jacks comprising an elongated metallic cylindrical sleeve of uniform cross section or diameter throughout its length, the inner wall of lsaid sleeve having a polished metal nish, a separate cylindrical cage telescopically fitting into one end of said sleeve, said cage having at least two ports therethrough, one of said ports opening ontofopposite'ends of said cage and the other port opening onto one end of the cage and also onto the circular periphery of said cage, valves in said cage for controlling said ports, said cage having a conically shaped nose attached to its free end, said nose having a port disposed centrally of the conically shaped outer walls of said nose, said port connecting the outer end of said nose with one of said passageways in said cage, the outer walls of said cage and nose lying wholly within the peripheral or outer plane of said cylindrical sleeve, the outer wall of said cylindrical sleeve being smooth from the end carrying said cage for the major portion of the length of said sleeve to provide a sliding surface to slide in a bore in the jack. v

7. An hydraulic jack comprising a relatively low basal casting having a centrally `disposed well and a concentrically surrounding shoulder portion around said well, said shoulder portion being internally threaded, the upper portion of said base concentrically about said threaded portion being provided with a laterally extending wall and an upper shoulder providing a second horizontally extending wall and a third upstanding shoulder, a cylindrical tube externally threaded and engaging the internal threads of said threaded portion surrounding said well to provide a ram cylinder, a ram in said cylinder, a sleeve having its lower end seated upon the horizontal portion just within said last mentioned shoulder and press tted and welded thereto to form a reservoir, a head interconnecting the outer ends of said tube and sleeve to close said reservoir at the top, said head having a passage to permit the projection of said ram therethrough, said base having a bore extending at an angle to the central longitudinal axis of said ram cylinder, the bottom ofv `said bore being formed as a valve seat, said valve seat having a centrally disposed conduit therein formed concentrically with the axis of said bore, said base having formed therein a passage connecting the reservoir with said. bore, a pump cylinder slidable in said bore, a combined ported and valved unit in the bottom of said bore and operably carried by said pump cylinder, the lower portion of said unit being'formed as a release valve to close upon said seat, a piston slidable in said pump cylinder, means for operating said piston, means for sliding said pump cylinder parallel to its longitudinal axis, and a port formed in said base connecting said well with the port formed concentrically at the axis of said valve seat, a geometric projection' or the Walls of said last named port passes above the topmost portions of said basal casting whereby before said cylinder is assembled on said basal casting said last named port can be drilled from the top of said base diametrcally through said well into said port that lies along the central axis of said bore in said base.

8. An hydraulic jack comprising in combination a base, concentric ram and ram cylinder means upstanding from said base, means on said base providing a reservoir, said base having a pump cylinder bore provided at its bottom with a release valve seat, conduits formed in said base interconnecting said pump cylinder bore, said release valve seat, said ram' cylinder, and said reservoir, a high pressure pump cylinder sleeve slidable in said pump cylinder bore and having an outer portion projecting beyond the exterior wall of said base, an actuator rigidly connected to that portion of said pump cylinder sleeve which projects outside of said bore, said pump cylinder sleeve having an inner end yportion the wallsl of which form a release valve to close upon said reiease valve seat, said inner end portion of said pump cylinder sleeve having an internal liquid passage therethrough connecting with the interior of said pump cylinder sleeve, valve means controlling said passage to permit liquid to flow therethrough only from said pump cylinder to said ram cylinder, said' end portion having a second conduit therein connecting the interior of said pump cylinder with said reservoir, valve means allowing liquid to lloiv through said second conduit only from said reservoir to said pump cylinder, a piston reciprocable in said pump cylinder sleeve, an actuator for said piston, and means for imparting rectilinear movement to said actuator to cause it to slide said pump cylinder sleeve in the bore of said base to position said release valve carried by said cylinder onto its seat.r

9. An hydraulic jack comprising in combination a base, concentric ram and ram cylinder means upstanding from the base, means associated with said base providing a reservoir, said base having a pump cylinder bore, said bore adjacent the bottom portion thereof being formed with a release valve seat and a connected passageway connecting with the ram cylinder, said bore likewise having a passageway connecting with the reservoir, a high pressure pump cylinder slidably mounted in said bore and being provided on its lower end with walls forming a release valve that are adapted to seat upon and close oiT the release valve seat, said pump cylinder being formed above said release valve portion with a port one end of which is constantly in communication with the passageway leading to the reservoir s and the other end of whichpassagewayleads to the interior of the pump cylinder, said last mentioned passageway having a valve seat therein and a valve for closing upon said seat in a manner to permit liquid to pass from said reservoir through said passageway to withinl the cylinder, but not reversely, said pump cylinderhaving another liquid passageway therethrough adapted to connect the interiorl or the pump cylinder with the passage in the base leading to the ram cylinder, a valve seat in said last mentioned passageway and a valve ior allowing liquid to pass from said pump cylinder through said passageway to said ram cylinder, but not reversely, a piston reciprocable in said pump cylinder, said pump cylinder projecting outwardly of said bore beyond the exterior walls of said base, an actuator rigidly connected to that part of the pump cylinder projecting beyond said base, and means for moving said actuator to slide said pump cylinder inwardly relatively to said base to seat the release valve upon the valve seat.

10. An hydraulic jack comprising in combination a base, concentric ram and ram cylinder means upstanding from the base, means associated with said base providing a reservoir, said base having a pump cylinder bore, said bore adjacent the bottom portion. thereof being formed with a release valve seat and a connected passageway connecting with the ram cylinder, said bore likewise having a passageway connecting with the reservoir, a high pressure pump cylinder comprising an alongated sleeve having a smooth outer wall, said sleeve being slidably mounted in said pump bore, a piston reciprocable in said sleeve, a collar rigidly connected to the outer end of said sleeve through which said piston reciprocates, a lever pivotally mounted on said base and pivotally connected to said collar, and means for actuating said lever to slide said sleeve inwardly of said bore, the lower end of said sleeve having fitting therein a ball valve cage and the lower end of said ball valve cage having connected thereto a cap having a conical outer wall providing a release valve adapted to seat upon and close said release valve seat, said cap having a central passageway extending therethrough, said ball valve cage having two passageways, one of which connects the passageway of the cap with the interior of the sleeve, a vaive seat in said passageway and a ball seatable thereon and disposed between said valve seat and the cap, the other passageway in said cage having one end connecting with the interior of the sleeve and the other end of said passageway terminating laterally of said sleeve and constantly communicating with the passageway inr the bore that connects with the reservoir, a seat in said last mentioned passageway and a ball seatable thereon., and means to reciprocate said piston.

11. An hydraulic jack comprising in combination a relatively shallow base having a well formed in its upper surface, said base about said well being countersunk and provided with an upstanding circular shoulder concentrically surrounding said countersunk portion, a ram cylinder tting to the walls of said well interiorly of said countersunk portion, and a sleeve concentrically surrounding said ram cylinder and itting to the upstanding circular shoulder, a ring-like cap closing upon the outer ends of said ram cylinder and sleeve to form a liquid-holding reservoir between the countersunk portion, the ring-like cap, the ram cylinder, and the sleeve, a ram in said ram cylinder, said base having a bore formed therein laterally of the reservoir and inclined with respect to the longitudinal axis of the ram cylinder, the

10 bottom of said bore being formed with` a valve seat anda passageway located "c,`,entrall y`'olfA said seat, said base having a pair1- of passageways formed in itsY walls, one of said passageways corinecting--with the passageway formed centrally of the seat in the bottom'of said bore', said lastmentionedv passageway -being-inclined upwardlyand connectingfwith the well, a'geometric projection of the-walls' of said last mentioned passageway passes above the countersunk portion oi the base and above the surrounding upstanding shoulder of the base whereby said passageway may be drilled when the ram cylinder and sleeve are removed, the second of said passagew-ays beingv formed in the base at an angle to said bore and connecting at its lower end with the bottom of said bore in said base and at its upper end with the reservoir, a high pressure pump cylinder slidably mounted in said bore and provided at its lower end wtih a valve cage, the lower portion of said valve cage carrying a conical nose, the walls of which are adapted to seat upon the walls of said valve seat formed in the bottom of said bore, said cage and nose being suitably ported and having valves therein interconnecting the rst and second pasasges with the interior of the pump cylinder sleeve, a piston slidable in said pump cylinder sleeve, means `for reciprocating said piston, and means on the base for slidably adjusting the pump cylinder sleeve with respect to the bore to permit the nose to be moved onto and away from the valve seat in the bore.

12. In' an hydraulic jack having a base provided with a bore, said base having thereon a ram cylinder, a liquid reservoir associated with the base, a pump cylinder comprising a sleeve of substantially uniform cross section throughout its length and having a smooth exterior slidable in said bore of said base, a ram for the ram cylinder, a piston reciprocal in the pump cylinder sleeve, conduit means in the base interconnecting the reservoir, the pump cylinder and the ram cylinder, ported and Valve means carried by the pump cylinderv sleeve for transferring liquid through said conduit means from the reservoir to the pump cylinder and from the pump cylinder to the ram cylinder upon reciprocation of said piston release valve, means including a valve seat formed in the base in association with certain of said ports and including a release valve carried by said ported and valved means and shiftable with said slidable cylinder sleeve and ported valve means, and actuated means connected to the outer end of said pump cylinder sleeve at a point beyond the outer end of the bore in the base when said sleeve is in its innermost slidable position therein for sliding said sleeve in a direction parallel to its longitudinal axis and in a direction toward the Valve seat and the baseto close the release valve upon its seat, said actuated means including mechanism whereby on release of said actuated means the pressure below said pump cylinder will freely slide said cylindrical sleeve outwardly to release the pressure therein back into the reservoir through certain of said ports.

JOSEPH J. MUELLER.,

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 849,147 Lewis Apr. 2, 1907 (Other references on following page) Number Number 12 Name Date Lindsay Sept. 1, 1936 Brunder Apr. 22, 1941 Nilsen Aug. 26, 1941 Gest et a1. Nov. 11, 1941 Cole May 12, 1942 Colwell et al May 19, 1942 Kirkland L June 27, 1944

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