US874700A - Hydraulic jack. - Google Patents

Description

5N0. 874,700. 7 PATENTEDDEC. 24, 1907.

1T. W. NELSON. I

HYDRAULIC JACK. APPLICATION FILED mm: 14. 1906. RENEWED 001'. 31, 1907.

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his fliiorneys 1105874300. I PATENTED DEC. 24', 1907.

L I -J. w. NELSON.

HYDRAULIC JACK.

APPLICATION IILED JUNE 14, 1906. RENEWED 001'. 31, 1907.

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JAMES W. NELSON, OF NEW YORK, N. Y:

HYDRAULIC JACK.

Specification of Letters Patent.

Patented. Dec. 24, 1902.

Application filed Julie 14, 1906I Serial No. 321.621. Renewed October 31. 1907. Serial No. 400,071-

To all whom it may concern:

Be it known that I, JAMES W. NELsoN, a citizen of the United States, and resident of the city of New York, borough of Brooklyn, county of Kings, and State of New York, have invented. certain new and useful Improvements in Hydraulic Jacks,- of which the following is a specification.

This invention relates to hydraulic jacks,

and particularly todouble or multiple-pump jacks, wherein, through the employment of all of the pumps, power is sacrificed for speed until the ram has been raised to the point where it receives the full weight of the load,-

allel to each other, and has in view, in con nection with such a pump or plunger arrangement, a minimum number of valves, and a valve arrangement whereby, withthe simplest possible mechanism, said valves will be under manual control to render one or all thereof inoperative for the purposes hereinafter set forth. 1

My invention will be more readily under- -stood by reference to the accompanying drawings, forming a part of this specification, and in which Figure 1 is a vertical, sectional, side elevation of a jack embodying my invention. Fig. 2 is a transverse section on an enlarged scale on the line 22 of Fig. 1. Figs. 3, 4, and 5 are vertical sections on the lines 33, 4-4

.and 55, respectively, of Fig. 2.

I have selected for the purpose of illustration a general type of horizontal jack, comprising a heavy metal shell or casing 6 having mounted in one side thereof a ram-cylinder 7 and in the other side a pump-block 8 and the pump mechanism. This-shell or casing 6 may be of any desired configuration, the ram-cylinder 7 being preferably screwed into a suitable screw-threaded aperture and the bottom thereof fitting within a socket, as shown, and the pump-block 8 bein provided with screw-threads at its upper en whereby it may be inserted in a suitable pocket theresnugly .known principles of hydraulics.

for and firmly held in place by means of. the threaded ring 9.

The shell or casing 6, therefore, as will be noted, provides a chamber .10 serving as both, a reservoir for the liquid employed and. for the pump operating mechanism. The latter comprises a shaft 11 extending through chamber, with suitable bearings inthe walls thereof, and provided on the outside of said chamber with a head 12 apertured for the reception of an ordinary pump handle lever (not shown) by means of which said shaft may be rocked. A block 13 is vertically slidable in suitable guides 14 14, mounted within said chamber 10, and is provided with an opening or pocket for the reception of a knuckle 15 fixed upon said shaft 11. It will be a arent that when said shaft is rocked the lil dck 13 will-be vertically reciprocated.

The block 13 carries the downwardly projecting piston or plunger rods 16 and 17 which extend into the corres onding pumpbores 18 and 19 in the pump lock 8. Each of the rods 16 and '17 is provided with a head or iston, 20 and 21, respectively, which fit in each of the pump bores 18, an 19, a tight 'oint being provided'by means of any well known method of packing. These bores are preferably of different d1- ameters, and'the piston-heads 20 and 2-1 of correspondin diameters. In this type of jack this di erence in diameter is not nec-.-

essary, as it is where the pistons are arranged end-to-end, or What may be termed a tandem one piston pro'ectmg' from the end of the other. It is we known the'object of a double-pump is to provldefor greater speed in raising the ram to where it receives the full wei ht of the. ad,

at which point one, prefera ly the larger,

pump is rendered inoperative in order to increase the power through a decrease in thearea of pressure surface under the w I therefore prefer to have-the piston of what may be termed the real pressure pump of corn,- paratively small cross-sectional area, the other of larger area in order to accelerate as muchas possible the speed of the, ingrramprior to its meetingthe load;

he pump bores 18 and 19 do not extend completely through the pump-block, but are permanently closed at the ottoms. Parallel thereto, and extending completely through the block 8, is the bore 22, which,

. Above the valve 28, a duct 30 connects the bore 22 with the chamber 31 below the smaller iston. Above this duct 30, the bore 22 is further contracted to form a seat for the valve 32, the valve 28 being provided with a stem 33 extending upward nearly but not quite to said valve 32. Above said valve 32, a duct 33 connects said bore 22 with the chamber 34 below the other pump piston, and above this duct 33 said bore 22 is again contracted to form a seat for the valve 35; the valve 32 being similarly provided with a stem 36 extendupward nearly but not quite to said ive 35. The valve 33 is similarly provided with a stem 37 extending into the upper and preferably enlarged portion 38 of said bore 22.

The shell or casing 6 is provided with an a erture or opening immediately above t e chamber 10, through which said chamber may be filled and which should be large enough to permit of the removal of the pistons and other parts for repacking, repair 7 or re lacement. Thisopening is preferably close by means of a screw cap 39, through which extends a rod '40 which may be moved up or down through a-limited distance by being screw-threaded. into the said lcap, rotation of said. rod 40 being facilitated by means of a hand-wheel 41 or its e uivalent, secured to said rod on the outsi e of the shell or casing 6. This rod extends downwardly into the enlarged portion 38 of said bore 22 to a point slightly above or just contacting with the stem 37 of the valve 35 when the latter is in its seat.

Under normal conditions, when the block 13 is raised in the manner hereinbefore indicated and therewith the pump pistons 20 and 21, a artial vacuum will be formed in each of t e um chambers 34 and 31. The vacuum in t e chamber 34 will, on account of the greater pressure of the liquid in the reservoir 10, unseat the valve 35 and the liquid will be forced into the said chamber 34. Similarly, the vacuum in the chamber 31 Will effect the unseating of the valve 32 and cause the liquid to fiow into said chamber 31. Upon the downward stroke of said istons, the greater pressure on the under si e of the valve 35 will seat the same and the liquid in both of the chambers 34'and 31 be forced past the valve 28 and through the ductfj26 into the ram chamber 24. In this manner the ram may be rapidly raised to the point where it re ceives thefull weight of the load. At this point, the-wheel 41 may be turned, forcing own the rod 40 until the valve 35 is unseated and held off its seat. Thereafter all liquid which is drawn into the chamber 34, uponthe up-stroke of the piston, will, upon the down-stroke thereof, be forced backinta the reservoir 10, while the'liquid which has been drawn into the chamber 31, the valve 32 still being operative, will be forced as before into the ram chamber and under greater pressure.

After the desired work has been done, and it is desired to release the li uid in the ram chamber in order to lower t e ram or contract the parts for subsequent or following operation, the rod 40 is further depressed, by means of the wheel 41, until first the valve 35 contacts with the stem 36 and unseats the valve 32, and second said valve 32 is sufficiently depressed to engage the stem 33 and unseat the valve 28, thus' opening and holding open the entire passage from the ram chamber 24 to the reservoir 10. The liquid in the ram chamber has thus free and uninterrupted passage from the ram chamber back to reservoir.

It will be apparent that while I have shown and described a jack in which the ram and ram chamber are located laterally of the pum block, the principles df my invention may e applied with equally satisfactory results to a construction of jack wherein the pump-block forms a part of the ram itself. Such construction would eliminate the necessity for a lateral duct such as duct 26, the bore 22 leading directly into the ram chamber below the pum -block, for whichpurpose the plug 23 would be suitably apertured.

It will be furthermore apparent that while I have hereinbefore referred to the device illustrated and described as being of a horizontal ty c, it being, possibly, better adapted for emp oyment in a horizontal direction than jacks in which the ram contains the pump-block and operating mechanism, it is nevertheless true t at this type of jack may be used vertically as well as horizontally and with equally effective results. My invention is therefore not limited to the type of jack nor to the specific construction herein shown and described.

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

1. In a hydraulic jack, a pump-block pro- .vided with a plurality of parallel pump-bores to ram chamber separate from the pumpchambers but communicating therewith, valves in said passage, and means for holding all of said valves off their seats.

3. In a hydraulic jack, a plurality of parallel pump-pistons, a series of check-valves to control the flow from reservoir -to ram chamber and means for positively unseating all of said valves by one operation.

4. In a hydraulic jack, the combination, with two parallel pumps, of a series of valves for controlling flow from reservoir to ram chamber and the first of which'checks back flow from one of said pumps only, and means for positively unseating said first valve, said means being further operable to unseat'all of said valves.

5. In a hydraulic jack, the combination,

with two parallel pumps, of a pump-block having corresponding pump bores and a separate fluid-passage from reservoir. to ram chamber separately communicating with each pump-chamber, an initial inlet valve to said passage, a final outlet valve therefrom, a valve intermediate of said pump-chambers, and means for renderinginoperative said inlet valve only or all of said valves.

6. In a hydraulic jack, the combination, with two parallel and connected pump pistons, of a pump block having corresponding pump bores and valves for said-two pump pistons in a single valve bore.

7. In a hydraulic jack, the combination, with two parallel and connected pump pistons, of a pump block having corresponding pump bores and superposed valves for said two pump pistons contained in a single bore separate from the pump bores but communicating therewith. v

In witness whereof, I have signed my name to the foregoing specification in the presence of two subscribing witnesses.

JAMES W. NELSON.

Witnesses WM. W. RoBEnTs, J. C. CONRA

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