US3081007A - Hydraulic jack - Google Patents

Description

March 12, 1963 H. A. LIGHTBURN HYDRAULIC JACK 2 Sheets-Sheet 1 Filed 001;; 25, 1960 March 12, 1963 Filed Oct. 25, 1960 H. A. LIGHTBURN HYDRAULIC JACK 2 Sheets-Sheet 2 United States Patent Office Claims 4 Claims. (Cl. 222--318) This invention relates to an and more particularly it relate-s to an improved hydraulic jack of the type which may be used on motor vehicles or the like. j

-Hydraulic jacks of many types have been proposed heretofore, but most of the hydraulic jacks in the lower price range have'been completely'sealed so that it becomes diificult or impossible to service them.

The main object of this invention is to provide a hydraulic jack which, though of relatively inexpensive construction, can nevertheless be dismantled for service purposes.

According to this invention the improved hydraulic jack comprises a pump and ram carried in a housing and provided with means to allow actuation of the pump to raise the ram and actuation of a release mechanism to lower the ram, the invention being characterised in that a valve block in the housing carries valves, and by a service plug in the housing which aligns with the valve block and valves to allow the valves to be removed from the valve block and housing for servicing.

A further feature of the invention is the arrangement of the release mechanism in such a manner that the pump and release mechanism can be withdrawn through a gland in the housing which is the gland for the pump. Simil'arly the rarn can be withdrawn through the ram gland.

To enable the invention to be more fully understood an embodiment thereof will now be described with reference to the accompanying drawings in whichi FIG. 1 is a perspecitve view of a hydraulic jack'with portion of the housing broken away to show the internal mechanism, I i Y FIG. 2 is a longitudinal section of the hydraulic jack, and

I FIG. 3 is a fragmentary plan view with the housing and pump plunger sectioned on line 3-3 of FIG. 2.

According to the embodiment illustrated, the hydraulic jack comprises a base 1 to which is welded a housing 2.

A ram cylinder 4 is also welded to the base 1 and is in alignment with an opening 5 in the housing, the ram cylinder 4 comprising alen gth of tubing machined at its open or top end to form a mount to receive a ram gland 6. The gland 6 carries sealing rings 7 and 8 held in position by a oirclet 9.

The ram 10 is internally threaded and carries the threaded stem 11 which has a cap 12 to engage the article to be raised and lowered. The lower end of the ram is of increased diameter to neatly engage theinsideof the ram cylinder 4. u I The lower end of the ram cylinder 4 isin communication for fluid fiow with a pump bymeans of a channel 17 in a member 18 which joins the ram cylinder 4 to the valve block 20, the valve block 20 being welded to the base 1 and also to the member 18 and having the pump cylinder 21 welded to it so that the pump cylinder 21 is substantially parallel to the ram cylinder 4.

The pump plunger 22 is slidable within the pump cylinder 21.

The valve block 20 has a bore 23 through it which varies in its diameter and accommodates two ball valves 24 and 25 respectively, a gauze strainer 27 being pushed into the bore 23 where it communicates with the inside of the housing 2.

improved hydraulic jack 3,081,007 Patented Mar. 12, 1963 The ball valve 24 serves as an inlet valve and engages its seat 28 when the pump piston 22 is moved downwardly on the pumping stroke, any hydraulic fluid in the passage 29 being then forced to push the outlet valve 25 from its seat 30. The outlet valve is free to move in an enlarged portion of the bore 23, but is urged against its seat 30 by a spring 31 which is retained by a screw threaded member 32 screwed into the end of the bore 23. A duct 33 opens downwardly from adjacent the outlet valve 24 to provide communication for the hydraulic fluid from the pump 21-22 to a channel 34 in the valve block which communicates with the channel 17'.

The screw threaded member 32, which has a screwdriver slot in its outer end, serves to confine the two ball valves 24 and 25 in the bore 23 and to provide a seat 35 for the relief ball valve 26. The relief ball valve 26 is held against its seat 35 by means of a pair of springs 38 and 39 acting on a rel e lever 40, the release lever carrying a screw threaded adjusting member 41 which is hollow and engages one end of the spring 38, the other end of which engages an adjustment plug 42 in a service plug 43 which is screwed into a box 44 welded into the lower end of the housing 2.

The release lever 40 has its lower end engaged in a slot 45 in the base 1 of the jack, so that it may rock through a limited angle due to clearance in the width of the slot 45 over the thickness of the metal comprising the lever 40.

The lifting capacity of the jack may be varied by changing either or both the springs 38 and 39. The final adjustment is made by means of the adjustment plug 42 which is locked in its final adjustment by means of the soft metal plug 64. Plug 64 is expanded into place by means of applied pressure such as a squeeze or hammer blow. The plug 64 is also the final oil sealing medium betweenservice plug 43 and the adjustment plug 42.

The lever is restrained side-ways by wings 46 on the release lever which fit on either side of the pump cylinder 21. The lever 40 is bent inwardly towards the pump piston 22', and is retained at its upper end adjacent to the piston 22 by means of the retaining spring 39 which embraces the pump cylinder 21 as well as the release lever 40. This spring 39 is arranged at an angle so as to have a component pulling the release lever 40 down into the slot 45. Guide members 47 are welded to the block 20 to further guide the lever 40.

The pump piston 22 has an operating stem 48 extending upwardly through a pump gland 49 on the housing 2, and a cam 50 is welded to this stem 48 to be in the path of the upper end 51 of the lever 40. The stem 48 has at its top an eye 52 through which an operating lever may be placed to engage the socket 53 in the housing 2.

Rotation of the stem 48 of the piston 22 about its axis causes the cam 50 to push the lever 40 outward to compress the spring 38 and extend the spring 39 which retain it against the relief ball valve 25, thus releasing the relief ball valve 26 from its seat 35 and allowing the hydraulic fluid from the cylinder 4 to discharge back into the housing 2 through the duct 17, 34 and 33. The clearance between the above mentioned cam 50 and release lever 40 in the engaged position can be adjusted by adjusting the screw threaded member 41 at the lower end of the release lever 40, this member being normally locked against rotation by the lock nut 55.

The stem 48 passes through the pump gland 49, this gland 49 consisting of resilient washers 56 held between upper and lower circlets 57 and 58. By removing the upper circlet 57 the washers 56 can be withdrawn from the tubular gland mount 60 in grooves of which the circlets 57 and 58 engage, and when the piston 22 is withdrawn, the opening left through the mount 60 is sufiiciently large to withdraw the lever 40 upwardly through such opening.

' ing from the top of A tool can also be inserted through thegland opening.

to remove or replace the gauze strainer 27.

A filler plug 52 allows the hydraulic fluid to be filled into the housing 2 and serves also as a level indicator to ensure that the fluid level is kept at the correct height. The line 63 indicates the fluid level.

The service plug 43 is screwed into the boss 44 and is co-axial with the bore 23 containing the ball valves 24 and 25 of the valve block 20, the member 41 also being in line with the bore 23 so that the ball valves 24, 2S and 26 and the springs 31 and 38 are all co-axially arranged.

The service plug 43 diameter is sufficient to allow the member 41 and its lock nut to be withdrawn through the opening when the plug is removed, and similarly the member 32 and the'various ball valves 24, 25 and 26 and springs 31 and 38 can all be withdrawn or replaced through the same opening.

The piston 22, lever 40, spring-39 and gauze strainer 27 can be withdrawn throughthe opening left atthe'top of the housing when the gland washers 56 are'removed, while the ram can be withdrawn from its cylinder 4 by' removing the gland 6 after taking out the circlet 9.

It will be appreciated from the above embodiment thatby removal of the pump glands 6 and 49 from their mounts, and the service plug 43, the operating members may be removed or replaced or adjusted as required.

What I claim is:

1. A pressurized liquid supply for a hydraulic jack comprising a pump reservoir, a pumpcylinder in said pump reservoir, a pump plunger in said cylinder projectsaid cylinder, a pump glandin said pump reservoir axially aligned with said pump plunger through which said plunger projects, means to engage a.

lever with said pump reservoir and said pump plunger,

a valve block in said pump reservoir beneath said pump cylinder having a duct communicating with said pump cylinder, valve seatings axially aligned in said valve block and valves including a release valve on said seatings, a removable service plug in said pump reservoir axially aligned with said valve seatings, a release lever having a lower end removably engaged on said pump reservoir between said service plug and said valve block and engaging said release valve, said release lever extending adjacent said pump cylinder and terminating below said pump gland, a cam on said pump plunger adjacent the upper end of said release lever to actuate said release lever when the pump plunger is rotated, and spring means to urge said release lever to hold said release valve on to it seat, said release lever being of such dimensions as to be withdrawable through said pump gland and said valves being of such dimensions as to be withdrawable through said service plug.

2. A pressurized liquid supply for -a hydraulic jack according to claim 1 further characterised in that the said valve block has a stepped bore through it shaped at one end to take a strainer, seatings formed within the block by expansion of the said bore, ball valves on said seatings with a smaller ball valve adjacent the strainer serving as an inlet valve to the pump and a larger ball valve adjacent the smaller ball valve to serve as the outlet valve from the said pump, a member screwed into the end of the bore remote from the strainer to confine a spring between it and the said outlet ball valve to urge the outlet ball valve on to its seat, said member having a diameter such that when removed both the inlet and the outlet ball valves are withdrawablefrom the said block, said relief ball valve engaging a seating on the said member.

3. A pressurized liquid supply for a hydraulic jack a-c cording to claim 1 further characterised in that the said valve block has a stepped bore through it shaped at one end to take a strainer, seatings formed within the block by expansion of said bore, ball valves on said seatings with a smaller ball valve adjacent the strainer serving as an inlet valve to the pump and a larger ball valve adjacent the smaller ball valve to serve as the outet valve from the said pump, a member screwed into the end of the bore remote from the strainer to confine a spring between it and the said outlet ball valve to urge the outlet ball valve on to its seat, said member having a diameter such that when removed both the inlet and the outlet ball valves are'withdrawable axially from the said plug, said relief ball valve engaging a seating on the said member, a screw thread adjusting member on said lever to contact said relief ball and of a diameter to allow the complete valve assembly and spring to be withdrawn from the-said pump reservoir when thesaid member is removed; said service plug being removably held in the said pump reservoir co-axially with the said bore in the valve block, and spring means between the said service plug and the said member carried by the said lever and of larger diameter than the member on the said lever whereby withdrawal of the said service plug gives access to the said valve mechanism for adjustment or replacement.

4. A pressurized liquid supply for a hydraulic jack comprising a pump reservoir, a pump cylinder in said pump reservoir, a pump plunger in said cylinder projecting from the top of said cylinder, a pump gland in said pump reservoir axially aligned with said pump plunger through which said plunger projects, means to engage a lever with said pump reservoir and said pump plunger, a valve block in said pump reservoir beneath said pump cylinder having a duct communicating with said pump cylinder, valve seatings axially aligned in said valve block having difierent diameters, valves on said seatings to control inflow and outflow to said pump cylinder, a spring urgingthe outflow valve on to its seat, an apertured plug screwed into said valve block co-axially with said valve seats, a valve seat in said plug, a release valve on said seat, a removable service plug in said pump reservoir axially aligned with said valve seats, a release lever having one'end removably disposed between said service plug and said valve block and engaging said release valve, said release lever projecting adjacent said pump cylinder and terminating below said pump gland, a cam on said pump plunger adjacent the upper end of said release lever to actuate said release lever when the pump plunger is rotated, and spring means to urge said release lever to hold said release valve on to its seat, said release lever being of such dimensions as to be withdrawable through said pump gland and said valves being of such dimensions as to be withdrawable through said service plug.

References Cited in the file of this patent UNITED STATES PATENTS 2,254,084 Nilson Aug. 26, 1941 2,466,815 Lightburn Apr. 12, 1949 2,618,929 Bidin Nov. 25, 1952 2,627,722 Johnston Feb. 10, 1953 2 ,662,475 McLellan Dec. 15, 1953

Claims (1)

1. A PRESSURIZED LIQUID SUPPLY FOR A HYDRAULIC JACK COMPRISING A PUMP RESERVOIR, A PUMP CYLINDER IN SAID PUMP RESERVOIR, A PUMP PLUNGER IN SAID CYLINDER PROJECTING FROM THE TOP OF SAID CYLINDER, A PUMP GLAND IN SAID PUMP RESERVOIR AXIALLY ALIGNED WITH SAID PUMP PLUNGER THROUGH WHICH SAID PLUNGER PROJECTS, MEANS TO ENGAGE A LEVER WITH SAID PUMP RESERVOIR AND SAID PUMP PLUNGER, A VALVE BLOCK IN SAID PUMP RESERVOIR BENEATH SAID PUMP CYLINDER HAVING A DUCT COMMUNICATING WITH SAID PUMP CYLINDER, VALVE SEATINGS AXIALLY ALIGNED IN SAID VALVE BLOCK AND VALVES INCLUDING A RELEASE VALVE ON SAID SEATINGS, A REMOVABLE SERVICE PLUG IN SAID PUMP RESERVOIR AXIALLY ALIGNED WITH SAID VALVE SEATINGS, A RELEASE LEVER HAVING A LOWER END REMOVABLY ENGAGED ON SAID PUMP RESERVOIR BETWEEN SAID SERVICE PLUG AND SAID VALVE BLOCK AND ENGAGING SAID RELEASE VALVE, SAID RELEASE LEVER EXTENDING ADJACENT SAID PUMP CYLINDER AND TERMINATING BELOW SAID PUMP GLAND, A CAM ON SAID PUMP PLUNGER ADJACENT THE UPPER END OF SAID RELEASE LEVER TO ACTUATE SAID RELEASE LEVER WHEN THE PUMP PLUNGER IS ROTATED, AND SPRING MEANS TO URGE SAID RELEASE LEVER TO HOLD SAID RELEASE VALVE ON TO ITS SEAT, SAID RELEASE LEVER BEING OF SUCH DIMENSIONS AS TO BE WITHDRAWABLE THROUGH SAID PUMP GLAND AND SAID VALVES BEING OF SUCH DIMENSIONS AS TO BE WITHDRAWABLE THROUGH SAID SERVICE PLUG.

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