US2038974A - Hydraulic jack - Google Patents

Description

April 28,1936. w N 2,038,974

HYDRAULIC JACK Filed July 28,. 1952 Snogntor m mw attorneys UNITED STATES PATENT OFFICE HYDRAULIC .uicx. Richard W. Werner, Milwaukee, Wis. Application July as, 1932, Serial No. 025,240

' 6 Claims. (Cl. 650-526 My invention relates to an improvement in hydraulic jacks.

Many types of hydraulic jacks have heretofore been provided wherein the essential parts comprise a hydraulically operated ram for direct application against an object tobe lifted, a cylinder in which the ram is mounted. pumping device for forcing fluid into the cylinder, areservoir for fiuidvarious conduits and check valves therein for controlling passage 01' fluid to and from the reservoir and cylinder, and a relief valve for permitting scharge of fluid from the cylinder when pressure upon the 'ram is to be released.

' My improved jack incorporates all or these teatures but avoids serious difliculties which have been heretofore encountered because of con-' apertures in the external walls to be plugged with resultant danger of leakage.

I have avoided danger of leakage in my improved hydraulic jack by installing my pumping device with such relation to the cylinder and reservoir that drilling operations necessary to the forming of the ducts in my jack are performed at such angles and with such relationship to ,the exterior walls of the base of the jack which houses the parts that. no high pressure ducts are directly accessible to the exterior walls of the jack in the completely assembled structure, and low pressure ducts are so disposed as to minimize the possibility of leakage.

The object, therefore, of my invention is to provide a hydraulic jack wherein all portions of the jack subjected to high pressure fluid are isolated in protective relation by zones of low pressure, whereby leakage-from the high pressure zones is only possible into the'low pressure zones or into the reservoir.

other features of novelty will be apparent upon examination of the description of my improved jack as hereinafter set forth.

In the drawing: Fig. l is a vertical section upon line l- -l in Fig. 2.

Fig. 2 is an elevation of a complete jack taken upon the pump side of the complete structure. Fig. 3 is a plan view of the completed structure. Like parts are identified by the samereterence characters throughout, the several views.

As indicated above, my hydraulic jack includes certain features which may be considered conventional in hydraulic jack construction. These features include a ram l provided with the usual leathercups and packing at l I and mounted in a cylinder l2 which is-jacketed by means 01 a cylindrical jacket sleeve Hi to form a jacket reservoir M, in which fluid is stored.

The cylinder and jacket are respectively 5 mounted in threaded engagement with the base 55 in a bore and counterbore as shown at l6 and H respectively. A reservoir cap I8 is in threaded engagement with the cylinder l2 at l9 and is so shaped as to provide a flange at 20 receivable 10 upon the end of the cylindrical jacket l3 to provide a closure for the top of the reservoir H. The cap Q8 is likewise bored and counter-bored to receive the ram Hi and packing?! respectively,

the packing 2! being retainedby a packing nut 22 in threaded engagementwith the cap l8.

In the ram it? and in threaded engagement therewith is an adjustable extension 23 for the ram and provided with a head 24 to receive the load which may be lifted by the jack.

Most hydraulic Jacks are provided with,.a pumping device andl have provided structure for that purpose involving certain novel features which will now be described.

The pump includes a pump cylinder 25 with a 26 plunger 26 to reciprocate therein; The piston 25 is provided with cup and packing leathers 21 somewhat similar'to those at I I upon the ram I0.

- Integral with the cylinder '25 I provide a check valve structure in an extension 28 of the cylinder 80 unit below threaded portion 29 of the cylinder 25. In'this extension various ducts and check valves are incorporated so that when activated by the piston 26 in cylinder 25 fluid 'i'n reservoir I4 is moved into the cylinder I2 below the ram I0 under such pressure as may be induced by the piston 26.

The base l5 of the jack is ported and provided with conduits intercommunicating with the conduits and check valves of the extension 28 as'i'ollows:

A conduit 80 between reservoir It and the extension 28 extends into an annular channel ll which is provided by reason of the undercutting oi the extension 28 and indicated clearly in Fig. 1.

The annular channel forms means for communication between the conduit 30 and a port 32 comprising an opening between the annular channel 3| and an interior chamber 33 in the extension 28. 4

From the chamber 33 conduits 34 and 35 extend in either direction co-axially with the cylinder 25 and comprise respectively passages for fluid to and from cylinder 25 and chamber 33, and a passage -from the chamber 33 through a 55 ball check 33 into a conduit 31 communicates .the reception of needle with conduit 36 for passing fluid into chamber 36 below the ram ID. The ball check 36 as shown in the drawing is in accord withusual practice in the art whereby to close conduitt to prevent passage of fluid upwardly from the conduit 31, but to leave the passages adequately free for passage of fluid from the pump through conduit 35 and into conduit 31. Conduit 38 is plugged at 40 by means of a needle valve 4| comprising a bleed which, when open, may pass fluid through conduit 42 into an annular space 43 at the end of the extension 28. This space 43 is preferably formed by chamferingthe end of the extension 28. A'milled channel 44 communicates between the annular space 43 and annular channel 3| so that fluid released by the needle valve at 40 may pass through conduit 42, annular space 43, milled channel 44, annular channel 3|, into conduit 33 and back into reservoir |4.

Tracing fluid through my hydraulic jack it will be seen that fluid is withdrawn from reservoir l4 through conduit 30, channel 3|, port 32, a ball check 45 into chamber 33 and thence through conduit 34 into cylinder 25, to which it is drawn by the partial withdrawal of the piston 26 from the cylinder 25. Reverse motion of the piston 26 will cause the closure of ball check 45 and the opening of ball check 36 for passage of fluid out of the cylinder 25 through conduit 34 and chamber 33, conduit 35, ball check 36, conduits 31 and 38 and the chamber 39 below ram l0 which, by reason of the pressure induced by the piston 26, will be elevated. Repeated motion of the piston 26 will cause repeated movements upwardly of the ram It as will be clear to those skilled in the art. When the ram is to be lowered under the pressure of the load which it sustains the fluid will be passed from the chamber 39 through the conduit 33 back to the reservoir, as heretofore described. It will be noted that the ball of ball check 45 is positioned by plug 46 in operative relation to the port 32 which it controls.

It will be noted that my cylinder 25 is disposed axially at an angle to the axis of cylinder I2 and that by reason of this axial disposition of the cylinder 25, all of the conduits with the exception of conduit 38 and the co-axial bores formed for valve 4| may be made without breaking any of the exterior walls of the base I5 and it will be noted that as to the bores for reception.of the needle valve 4| and conduit 38, the disposition of the needle valve against its seat at 40 is such that any leakage at the needle valve seat 4|! is passed into conduit .42, which is under fluid pressure induced only by the head of fluid in the reservoir |4. Therefore, plug 46 through which needle valve 4| extends in threaded engagement is only subjected to reservoir pressure of fluid.

High pressure of fluid is only subjected to Joints between cylinder l2 and the base I5; between conduit 36 and conduit 42 controlled by needle valve 4|; at joint 41 between the extension 28 'and base |5;' between chamber 33 and port 32 during the pressure stroke of the piston 26 and between plug 48 in the extension 28 and the annular channel 3|. In all of these places leakage of fluid at these joints or valves may only pass into ports, conduits or chambers which will receive the escaping fluid and return the fiuid to the main reservoir l4.

Attention is likewise called to the lever of the second class embodied in the piston actuating mechanism shown in the drawing and which includes a lever socket member 50 provided with ears 5| to embrace the piston 26, and provided with pivot pins 52 and 53. Pivot pin 52 passes between the ears 5| and through an aperture near the end of the piston 26. Pivot pin 53 extends through the handle socket member 50 and receives upon the ends of such pivot 53 side fulcrum members 54 and 55 respectively. Hollow handle 56 extends into the socket member 50 and is pro vided with slots 51 to receive a pin 58, comprising a part of needle valve 4|.

I have found that this arrangement of parts particularly facilitates the manual control and reception of piston 26 when the jack is disposed under an automobile axle, since the angular disposition of the handle 56 over the end of the piston 26, which in turn is angularly disposed with reference to the base I5 of the jack itself, is conducive to easy manipulation.

I claim: 1

1. The combination with a base bored and counterbored for the reception of a ram cylinder and reservoir cylinder respectively and provided with a laterally disposed bore axially and angularly disposed with reference to the axis of the flrst bore, of a pressure conduit comprising an extension of and co-axial with the laterally disposed bore, a relief conduit extending from the margin of the laterally disposed bore to the base of the first bore and intersecting the pressure conduit, a supply conduit connecting the counterbore and the laterally disposed bore and a pump unit with a chamfered extension receivable in the laterally disposed bore and provided with an undercut side wall portion to register with the supply conduit, the pump unit being also provided with check valves and conduits to receive fluid from the supply conduit through the undercut portion and pass said fluid to the pressure conduit, and a bleed valve in the relief 'conduit to release fluid from the ram and permit its passage past the chamfered pump unit through the undercut portion to the reservoir.

2. The combination with a hydraulic jack provided with a base, a ram cylinder, a ram therein,

and a reservoir, of a conduit comprising a substantially straight hole extending from the exterior of the base into the lower portion of the ram cylinder and provided at a point intermediate the exterior wall of the base and the ram cylinder with an enlargement of the conduit, a shunt conduit extending from the enlargement of the flrstmentioned conduit to the reservoir, a pump to receive fluid through the shunt conduit from the reservoir, a high pressure conduit extending from the pump to the first mentioned conduit and forming agjunction therewith intermediate the shunt conduit and the ram cylinder, and a bleed valve between the first-mentioned conduit and the shunt conduit, so positioned as to block the opening in the exterior wall of the base, said bleed valve extending into said enlargement.

3. A hydraulic jack comprising the combination with a jack base and a cylinder extending vertically therefrom, of a lifting plunger in said cylinder, a reservoir carried by said base, a pump chamber provided with a duct communicating with said cylinder, a bypass duct in said base leading from said pump chamber to said last mentioned duct and provided with a valve seat, a duct close said chamber and provided with valved inintermediate point with a valve seat shoulder,

ternal passages in a terminal portion seated against said chamber about the point of communication therewith of the duct leading from the chamber to the Jack cylinder, one of said passages registering with the last-mentioned duct and the other passage registering with the duct leading from the reservoir, a pump piston operable in said casing and means supported on said base for the actuation of said piston to receive liquid from said reservoir and to expel such liquid under pressure through the duct leading from the chamber to the jack cylinder.

4. In a hydraulic jack, the combination with a base provided with a pump chamber and ducts. of a jack cylinder projecting upright from said base, a reservoir having a portion within said base and directly communicating with said chamber by one of said ducts, another of the ducts of said base comprising a high pressure duct leading from said chamber to saidcylinder and another of the'ducts in said base comprising a bypass having angularly related portions whereof the first leads directly from said high pressure duct to the exterior of the base and is provided with a valve seat shoulder and the sec ond leads from the first externally of said shoulder to said chamber, a valve adjustable in said base axially of the first portion of said bypass duct into and from engagement with the shoulder thereof to close and open the bypass, a pump casing having a terminal portion seated against the end oi said chamber about the point of communication of the high pressure duct therewith 1 and. provided internally with a valved passage controlling communication with said duct, said chamber providing communication outside of said pump casing between said'reservoir duct and the second portion of said bypass duct, a valve controlling the admission ofliquid from said chamber to the pump casing and a pump piston reciprocable in said pump casing to draw liquid from said reservoir through said last mentioned valve and to expel said liquid through the high pressure duct to said cylinder.

5. A hydraulic jack comprising the combination with an upright cylinder and a concentric reservoir, of a base with which said cylinder and reservoir are in liquid" tight connection, a jack plunger operative in said cylinder, a duct in said base leading directly from the bottom of said cylinder in an upward direction to the external surfacepi' said base, and provided at an avalvescrewthreadedintheendofsaidduct for axial adjustment-therein to and from said casing provided with means connecting it in,.

.screw threaded engagement with the outer end of the chamber and provided with a reduced terminal portion ailording clearance from the wall of said chamber for 'thefiow of liquid through said bypass duct from said first mentioned duct to said reservoir, said terminal portion being seated against the bottom of said chamber, and having a passageopening to said bottom and another n: opening into said casing from said chamber, a high pressure duct v commun'icating with said first mentioned passage and said cylinder, check valves in the respective passages of said pump casing and a displacement piston operable in said casing to draw liquid from said reservoir and chamber into said casing and to expel such liquid through said highpressure duct to said cylinder.

provided at an intermediate point with a valve seat shoulder, a bleed valve threaded in said duct for axial adjustment therein to and from said shoulder, a pump chamber formed in said base and opening therefrom along an axis inclined with reference to said cylinder and intermediate said cylinder and said duct, a bypass duct leading from said first mentioned duct externally of said shoulder to said reservoir, a pump plunger operative in said chamber, a high pressure duct extending from'the chamber to i the first-mentioned duct, and a supply duct in communication with the reservoir and leading to the high pressure duct, and check valves at the

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