US2464254A

US2464254A - Hydraulic jack

Info

Publication number: US2464254A
Application number: US534210A
Authority: US
Inventors: Joseph J Mueller
Original assignee: Auto Specialties Manufacturing Co
Current assignee: Auto Specialties Manufacturing Co
Priority date: 1944-05-05
Filing date: 1944-05-05
Publication date: 1949-03-15
Anticipated expiration: 1966-03-15

Description

March 15, 1949. J. J; MUELLER HYDRAULIC JACK Filed'May 5, 1944 Patented Mar. l5, 1949 HYDRAULIC JACK `oseph J. Mueller, St. Joseph, Mich., assigner to Auto Specialties Manufacturing Company, St. Joseph, Mich., a corporation of Michigan Application May 5, 1944, Serial No. 534,210

(Cl. Sil-62) 1 Claim. 1

This invention relates to hydraulic jacks, and while the invention is capable of broad adaptation to a jack of the general principles herein illustrated, the invention is for purposes of illustration, but not by way of limitation, shown as applied to a jack of the construction set forth in my co-pendng application Serial No. 468,768, filed December l2, 1942, now patent No. 2,412,414, issued December 10, 1946.

Therefore one of the objects of the present invention is to provide a jack which is an improvement on the jack disclosed in my before mentioned application, and wherein a valve seat is formed in the upper end of the central bore of the stationary ram, and a valve rod and valve are mounted in the underside of the top portion of the slidable rain cylinder so that when the cylinder is raised to a predetermined height the valve will cut olf the pressure fluid to the underside of the ram cylinder, whereby to prevent inf jury to the jack if the hydraulic pumping action be continued beyond Such predetermined lifting range.

Yet another object of the invention resides in providing a jack having an upstanding stationary ram and a relatively slidable ram sleeve enveloping the ram, the top surface of the ram sleeve being provided with a threaded plug, the head of which is arranged so that pressure against the underside of the ram sleeve normally tends to seal the plug more tightly, the plug being provided with a central threaded aperture to receive and carry a depending valve rod cooperating with a sleeve provided with a cornplementary valve seat therein formed in the upper portion of the central bore of the stationary ram cylinder, whereby to cut off further uid presure against the underside of the ram sleeve at a predetermined point in its elevation.

These and other objects of the invention will fr be apparent from the following specification, when taken in connection with the accompanying drawing, wherein:

Figure 1 is a perspective View of one form of the invention;

Figure 2 is a sectional view taken on the line 2 2 of Figure 1;

Figure 3 is a sectional View taken on the line 3 3 of Figure 2;

Figure 4 is an enlarged section taken through the oil reservoir, showing the by-pass valve; and

Figure 5 is a section corresponding to Figure 2, but showing the cut-off valve in its uppermost position with respect to the stationary ram cylinder.

Referring now to the drawings in detail, the particular jack with which the invention is illustrated embodies a base 2 which is provided centrally with an upstanding wall 4 providing a central well. The circular inner faces of the upstanding wall 4 are threaded as at 5. Onto this threaded portion screws a stationary ram 8 having a central longitudinally disposed liquid passageway It. An elongated hollow ram cylinder in the form of the sleeve l2, preferably formed of malleable iron, encloses the stationary ram 8. This shiftable rain cylinder l2 is provided with an inwardly extending shoulder Hi at its top and the upper surface of the ram is suitably knurled or fashioned as at l to grip the load to be lifted. The top of the ram cylinder is preferably provided with a screw threaded opening into which is threaded the plug 20. This plug is provided with a head 22 or; its inner end and with a hexagonal recess 24 in its outer or top end. By this arrangement the fluid pressure within the ram cylinder l2 tends to forceA the plug tightly to its seat to prevent leakage. The ram cylinder i2 at its bottom is suitably threaded as at 39 to receive a packing 32 which lies between the bottom of the stationary ram S and the inner smooth surface of the ram cylinder l2. At its outer bottom end the ram cylinder is provided with a foot lift step 34 which forms a second load receiving surface. The bottom of the ram 8 is recessed as at 36 and joins the internal passageway It formed centrally of the ram. It is particularly to be observed that there is a minimum of space between the external smooth wall of the ram and the internal smooth wall of the ram cylinder I2, other than that space demanded in order to permit the ram cylinder l2 to elevate or depress relatively to the stationary ram 8. By means of this construction it will be noted that any oil which leaks into this space between the external vertical face of the ram S and the internal vertical face of the ram cylinder I2, on elevation of the ram cylinder will be permitted to escape upwardly to the space between the top of the stationary ram and the underface of the ram cylinder i2 and will not be forced downwardly past the packing 32. In this manner escape or seepage of the oil to an external surface of the ram cylinder is precluded.

Cast integrally with the upstanding wall li of the base is an oil reservoir 33. This reservoir is preferably cylindrically shaped and is disposed laterally of the central axis or passageway I 0 of the upstanding ram 8. The cylindrical reservoir extends substantially from one side of the base to the other, as indicated in Figures l and 3, and this cylinder is provided with a threaded opening at each end, such as i0 and 02, to receive threaded plugs Ml and 46 whereby to facilitate the casting of the reservoir as well as to permit the filling of the same with suitable liquid, preferably oil. 'The plugs All and I6 are countersunk at their outer ends in a hexagonal manner to permit the removal and insertion of the same.

A plunger pump cylinder is cast integrally with the oil reservoir. As shown in Figures 2 and 3, the walls 48 are internally formed centrally of the reservoir, extending vertically downwardly as indicated in the above mentioned figures. At the top the pump cylinder casting is shouldered as at 50 to receive a threaded packing plug or ring 52 which serves to hold suitable packing 5d in position to prevent leakage outwardly around the pump piston. A pump piston 5t is adapted to be reciprocatingly mounted within this cylinder and to this end the pump piston is provided at its outer end with a cross bore 5B in which a pin i523 is disposed, and the pump piston having at its inneror'opposite end a threaded shank to which is attached a nut 5I which supports a collar 50 being surrounded by leather pump washer d i, as shown in Figure 3. The opposite ends of the pin 60 lie in registering apertures 62 and 5d of ears and 68 of an actuator 'l0 pivoted as at 'I2 to the outer end of the links 'lli which are in turn pivoted by means of the pin l to the ears E52 integrally cast on the top surface of the reservoir 3S. The actuator 'i0 is provided with a socket St in which an operating handle EB may be inserted whereby upon reciprocation of the handie in a vertical plane the `high pressure pump will be actuated in a manner well known in the hydraulic jack art to draw liquid from within the interior of the reser" voir 38 through the cast passageway @l0 past the ball valve 92. This ball valve, as shown, is normally held by means of a spring aten its seat 96. The liquid will be drawn inwardly by an upward movement of the piston 55 into high pressure cylinder chamber 35i and then upon downward movement of the piston. 5S the ball 92 will be pressed against the seat and the liquid will thence be transferred past the larger balltgthence through the transversely extendM ing cast opening E00, thence through channel I02-I04`into the recess 36 of the ram 8, thence up the longitudinal passageway I0 of the ram to cause the upward projection of the ram cylinder I2. The ball valve 08 is normally pressed to its seat by means of the spring 99.

A diagonally disposed passageway Iii@ connects the passageway Id? in the base of the jack with the reservoir and the upper portion of this cross passage I06 is provided with a valve seat E03 which is normally closed by means of a valve formed on the inner end of a valve stern IIi which by means of the threads iii engages cerresponding threads on a sleeve I i4 cast integrally withfthe inner walls Il of the reservoir. Suitable packing Ihi held in position by means of a threaded thimbie prevents leakage past this valvefstem I iii. Rotation of the outer end of the handle I2? of this valve stem opens communica tion between the reservoir and the passagewa I0? .so as permit the passage of liquid directly from the stationary ram f8 back into the resern voir whereby to release the pressure in the space between the ram and ram cylinder to permit the descent orfdownwardiinward movement of the ram cylinder I2 relative to the ram 8 and the base. It will be noted that by this arrangement and by forming the passageway IGS directly Within the inner wall of the oil cylinder, leakage is precluded since the oil in escaping must pass directly into the oil reservoir.

It will be noted that passage |02 is closed at its outer end by a suitable threaded plug |03, and it will be likewise noted that the passage I00 is closed by another threaded 4plug I 2d, and in order to give access to this plug the bottom portion of the casting is hollowed out arcuately as at I26.

The front wall of the reservoir 33 is provided with spaced outstanding ears IZB to which are pivoted the opposite ends of a handle |30 for lifting the jack at its base.

It will be noticed from Figure 3 that the passageway 00 within the oil reservoir is arranged so that the end di of this passageway terminates relatively close to the vertical end wall 93 of the oil reservoir near ll plug 4.: By thisarrangement the jack can be positioned forhorizontal operation on one of its sides, whereby reservoir.;

plug Lil-i is downward, and still draw iiuid through port 9i from the lowermost portion of the reser.

Voir.

In accordance with the improvedfeatures of-v this invention, means is provided inassociation with the ram and ram cylinder,` and preferably the central oil conduit i0, for limiting thevertical lift ol the ram cylinder I2 with respect to the sta.l

tionary ram 8. In the construction illustrated,-

tion of the passageway so as to prevent liquid `being forced into the-space-between the. upper surface of the ram 8 and the undersurface of.. In the presentfinstance` this is accomplished Yby providing they plug.:

the ram cylinder I 2.

20 with a threaded hole 95 to receive, an

elongated valve rod 91 Ahaving, on* its.b0ttom,Y

This valve is adapt-.

end a tapered valve 99. ed to seat against a valveseat IBI formed in -a threaded sleeve 03 which screws into a threaded internal bore it at the'top of the `oil passage I0 of 'the ram t.

is provided with an unthreaded portion vIIl'l having inwardly tapering walls H39 whereby to guide the valve 00 as it moves ydownwardlyv when the sleeve-like ram cylinder I2' descends. Inl the operation of this device, when the ram cylinder I2 i reaches the position shown in Figure 5, thetasageway I0 is thus cut oli no further elevation. of

the ram cylinder is possible so thatany attempt f to continue thevelevation of thefram cylinder will l prove fruitless.

Obviously the invention-.is not limited to the specific details of construction disclosedwhereinmlbut is capable of other modifications-and changes Without departing from the spirit and-scope of the.

appended claim. I

Having thus described my invention', what'l claim as new and desire lto secure byLetters Pats. ent is:

In an hydraulic jack, the" combination of fa.

base, a ram stationarily` projecting- :upwardly` therefrom and Ahaving a 'central-vertical liqui passage, a sleeve-like ram cylinder adalvtedrtoditk rihe bottom of this passage. in which the threaded sleeve IQE lthreadedl-y-engages over the ram, said jack having a liquid reservoir associated with the base, pumping means associated with the base including passages interconnecting the reservoir, the pumping means, and the central passage of the ram for drawing liquid from the reservoir and forcing it under pressure to the central passage of the ram, oy-pass means for relieving the oil in the ram and passing it back to the reservoir, the upper portion of said vertical passage in said ram being provided with an enlargement the upper portion of which is threaded, a hollow sleeve screwing into the threads of said enlargement, the bottom inner wall of said sleeve being formed with tapering Wall portions forming a valve seat, the enlargement below said sleeve being tapered conically inwardly and downwardly, the top of said ram cylinder having a central threaded opening, a plug having an external thread screwing into said opening and having a head larger than said opening and disposed internally of said cylinder to seal said opening under the pressure conditions to which the underside of said head is subjected. said plug head having a central bore and a rodlike element mounted in the central opening of the plug head and extending downwardly through the passage through said sleeve and provided on its lower end with a tapered valve to close upon the valve seat formed by said sleeve, said tapered walls of said enlargement forming a guide to center said valve as it moves downwardly.

JOSEPH J. MUELLER.

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

UNITED STATES PATENTS