US2032309A - Service jack - Google Patents

Description

Feb. 25, 1936. o. H. RECHARD' El AL SERVICE JACK Filed Jan. 26, 1952 2 Sheets-Sheet l I Q I Feb. 25, 1936.

o. H. RECHARD ET AL 2,032,309

SERVICE JACK Filed Jan. 26, 1932 2 Sheets-Sheet 2 A AER Patented Feb. 25, 1936 UNITED STATES SERVICE JACK can u. Rechard mil OlcI-l' r. kulilm, York,

Pa., assignors, by mesne assignments, to American Chain Company, Inc New York, N. Y., a corporation of New York Application January 26, 1932, Serial 170.588,!

. :8 Claims. (Cl. 254-2) This invention relates to improvements in hy-.

draullc iacksuand-the object in general is to providers light, compactjack of relatively great speed, operatingdlexibillty and power but one whl'ch lzc'annot' -be either by overloading orbydrivirig the-lifting lever above, a predetermined=height.-

A specific of the-invention is the provision of- -a sinfle element-whichperforms three functions: flrstrritxautomatically prevents over-. loadlng-ethe iackisecond-,- without putting any strain onany: ot-thc parts, it prevents the lever arm -ri i above; a predetermined height, and third,.it causes: the load to-be lowered when actuated-by a release lever on the jack handle.

Another object-oi the invention is to provide.

a hydraulic jack wherein the ram is so positionedwith relation to the lifting lever that it exerts. maximum-lifting force at the time when i the lever has made.-one half of its upward swing. Other objects 1 of -the= invention will-.be made apparent-by the following-description when taken with the-accompanying drawings in which:

Figurelisaplanfi Figure 2 is a side elevatiomrolnitting the handle.

Figure; 2 is a full side view. Figure 3 is a longitudinal vertical section.

4 is a sectional detail of my improved check valve. I l Figure 51s a side view partly in section showing the'iack at about halfelevated position.

Figure-6 is'a detailof the safety valve operating mechanism.

The main frame, consisting of spaced side S members which may be steel stampings or plates but-are. preferably built up by welding to the front portions of strips II the triangular plates II, is 'supportedat front and rear by wheels I! and i4 onaxles Ii and I6 respectively, extend- 3 ing thru the ends of the strips II. The side plates are-heldin spaced relation at the front by the main body ii; at the rear by the pipe spacer II on axle l5 and at the apex by main pivot bolt 20, on which latter is pivoted 'the- 5 forwardly extending handle II and therearwardly=extcnding lifting lever or arm 12.

This lever arni,- 2!; which for strength vis. channel-shaped structure, is pivoted on the main pivotal axis Ilbynieans of two; lugs 23 which 3 are forward extensions of the depending flanges 24-."These flanges as well as'the web IS-converge toward the -other end into an integral transverse journal 26 which 'carries thebolt 21 for pivoting the saddle or rest plate II- by means of down- 5 wardly and rearwardly extending ears 3|, which are integral extensions of the concave support ing plate of the saddle. As the lifting lever swings about the-pivot 2| the-upper surface of the rest plate II ismaintained in a horizontal position by means of the ll pivoted to the I lowest comers of the-saddle andat their forward ends to the inner side ofathe-triangular plates l I .by studs 33, the constantly horizontal position of -the.-saddle being due to what is known as. the-parallel motion linkage relation of the drags -andetheliftingarm. Near the middle of one drag link 3! is connected one end of a strong spring 34, the other: end being connected to the rear of the lever}! by a depending car 35, this spring tending to return the lifting lever toits l5 lowest position with the rest plate 28 in front oi 'the rear ground wheels I! and somewhat below thelevel of the top of these wheels. In this position the lower edges ofthe flanges 24 rest on the drag links II and the web li'rfiay or may not rest on the lip of the ram cylinder 31. It'will be seen-"in 3 that the cylinder 31 is an integral part ofthe body I! which inall interconnected-by the central bore 44 in'the floor. Thus one single casting contains themare hydraulic 'unit eliminating all pipes and flt- 80 tingsand making the jack substantially" leak ,proof since as will be more fully pointed out.

presently, all possible leakage is drained back into the reservoir it. I

Any oil that maybe forced up around the skirt 35 45 of the ram-f will iiow over the lip of -the skirt into the-cavity 48 aroimd-the connecting rod 41 but as the ram rises all but a small portion of this oil'will flow out the ports ill of the skirt into the groove 5| near the topof the cylinder 31 from which it drains by way of the passage 52 back into the reservoir. The leakage that may occur while the ram is in its-raised position will of course be trapped by the same groove 5| and flow directly thru the'passage 5 2, the'ilow being aided by the tilted position 'of-the cylinder. Should any oil leak by the pump piston 53 itcannot get outside because of the heavypacking ;"aroundthe piston in the cover 55" but due tothe spacing ring 56 such leakage ilowsover the lip of the pump cylinder 42 directly back into the reservoir. The latter is further madeoil tight by positioning a gasket 51 between the and the cover which latter is secured in place by a plurality of bolts 58.

.No leakage occurs around the release rod il because its stroke is too short to carry any oil to the cover 55 which fits it rather snugly and also I being centrally located it would be necessary to tip the jack over before any oil could flow out around the rod. Since the opposite ends of the central bore 44 are made oil tight by means of the plugs 6i and 62 it is apparent that I have provided a. practically leak proof hydraulic unit.

In order to make the cylinder 31 dust proof I secure around its top one end of a fabric sleeve 53 the other end being secured to the connecting rod 41 just below the upper end where it makes con-' 1 may be provided to cover-the pump piston 53 piston 53 by the links 85' pivoted at 86 and 61 and where the jack is to be used in very dusty locations but for most places the benefit derived does not warrant this extra expense.

The jack handle 2| is connected to the pump is limited in upward movement with respect to the body I1 by the spotting link 58 pivoted on pin 18 carried by lugs extending forwardly from the front wall 40 of the reservoir. The link 58 is useful when it is desired to move the jack from place to place about the garage, the link being used to raise the smaller front wheels off the floor by an upward movement of the handle which allows the jack to rest on the rear wheels only so as to be guided and spotted with ease. At the end of the handle is provided a hand grip anda hand lever 12 the latter connected by rod 13 to the bell crank 14 which may be operated to raise the release rod 60 irrespective of the position of the handle.

The rod 60, located directly under the main pivot 20, is part of a combination safetyrelease and control valve device comprising a valve cage 15 screwed into the fioor 43 making a Junction with the passageway 44 and within which cage is carried a ball.valve 16 resiliently held inits seat by theend 11 of the rod 68 around which is the spring 18, compressed between the cover and the adjustable bifurcated member 88, the latter being attached to the release rod in any chosen manner preferably by the threads as shown in Figure 3. On the base of the pump cylinder 42 is provided a vertical, radial fin 8| which is straddled by the fork of the member ll and prevents this spring adjusting member 88 from. turning with the rod 60 but allows it to reciprocate freely therewith; Adjustably secured to the top of the rod between two lock nuts 82 and '83 is a stirrup shaped member 84 thru which extends the curved arm 85 of the above mentioned bell crank lever 14. When actuated by the-hand lever 1-2 the curved surface of the lever 14 engages the cam surface 88 of the stirrup 84 and raises the release rod against the tension of the spring 18 and thus allows the ball valve 16 to rise should there be any pressure below it. The cam surface 88 is wide enough to accommodate also the finger like cam 81 which is an integral forward extension of the web 25 of the lifting arm so that this cam extension 81 turns with the lifting arm about the pivot 20 and when the saddle or rest plate 28 at the endof the lifting arm reaches itsmaximum predetermined height the cam 81 engages the surface 86 and raises the rod 58 slightly. .to release the valve 16 momentarily which allows the excess oil to flow from the passage 44 back into the reservoir.'

Operation.The reservoir 38 is first filled to the proper level with a light grade of oil which is poured in thru an opening in the cover 55 after which the opening is closed by the plug 88 which seals up the reservoir. The jack now is moved to the desired place and by means of the handle 2| is spotted under the load to be lifted, for example 1 an automobile, the axle of which is to be engaged by the saddle 28 as the lifting arm 22 is raised.

On the upward stroke, the handle lifts the plunger 53 which action creates a suction in cylinder 42 drawing ball 98 forwardly against its seat in the rear half of the valve cage 9| and releasing ball 92 from its seat in the cage end of the plug 93 so that it engages the retaining pin 96 which prevents ball 92 from closing the passage 95. A charge of oil from the reservoir 38 is thus delivered thru passage 94 around the ball 92, thru passage 95 and into the pump cylinder 42. On the down stroke of. the handle the plunger 53 forces the oil from the pump cylinder, thus forcing ball v 92 into its seat and also forcing ball 90 out of its seat against the pin 91 which prevents the passage 44 being closed. The oil therefore passes thru passage 44 into ram cylinder 31 where it raises the ram 46 and consequently the lifting arm 22-. Continued up and down movement of the handle will thus force a sufilcient quantity of oil under the ram 45 to raise the arm to its maximum predetermined height at which time the cam extension 81 engages the cam surface 86 of the stirrup and raises the rod 60 from the ball 16 1 which, being forced upward by the oil under pressure in passage 44, allows the oil to flow from underthe ram 46 thru the passage 44 and back into the reservoir 31. This flow into the reservoir continues until the arm 22 lowers a sufficient amount to disengage the cam 81 from the cam surface 86 which allows the rod 60 under the urge of its spring to press the ball 16 back into its seat. Thus continued pumping will inno way injure the jack since the valve 16 is always This limit can be necessary to press the small hand lever 12 against the larger grip which action as explained above turns the bell crank lever 14 about its pivot bringing the arm 'into engagement with the stirrup which raises the rod and releases the valve 16 allowing the oil to flow from under the lifting ram back into the reservoir as long as the small hand lever is engaged by the operator. The

curved arm 85. is made sufliciently long so that it may operate rod 60 in any position of the handle 2|.

The tension of the spring 18 may be adjusted by screwing the rod 60 into or out of the bifurcated member 80 and by this means the maximum load which the pack will raise may be predetermined for if the operator should attempt to raise a greater load the pressure built up under the lifting mm by continued pumping will be equaled in the passage 44 and will raise the ball 16 from its seat against the predetermined tension of the spring 18 and'all the oil that is pumped after the the main pivot to the saddle or rest plate when the latter is halfway between minimum clearance and maximum lift.

What we claim is:

1. In a hydraulic jack having a ram, a single casting comprising a ram cylinder, a pump cylinder and a reservoir, the bottom of the reservoir being integral with the bases of the two cylinders, said casting having a single bore therein for connecting the pump and ram cylinders, and valves in one end of said bore for controlling the flow of fluid between the reservoir, the pump and the ram.

2. In a hydraulic jack having a lifting plate driven by a ram and a pump plunger operated by the jack handle, a ram cylinder, a pump cylinder, a reservoir surrounding the pump cylinder, afloor for said reservoir integral with the bases of said cylinders and having a single straight bore therein interconnecting said pump cylinder, ram cylinder and reservoir, valve means in said bore permitting oil to be drawn into said pump cylinder only from the reservoir, and permitting. oil to be driven from said pump cylinder only into said ram cylinder, and a valved passageway located between the two cylinders establishing communication between said bore and said reservoir whereby the oil may be allowed to flow from said ram cylinder back into said reservoir.- I

3. In a hydraulic jack, a hydraulic unit consisting of a single casting containing a ramcylinder, a pump cylinder spaced from said ram cylinder, a reservoir substantially surrounding said pump cylinder, and a cover for. the reservoir having an apertured recess registering with the bore of the pump cylinder, the recess being on the under side of the cover and cooperating with the top of. the pump cylinder to form an annular packing glandto accmmodate packing for the pump plunger. j i

' 4. In a jack, a wheeled truck, an upright pump,

.and a nearly upright ram carried on said truck,

and a load raising arm pivoted on a transverse pin located between and above the pump and rain, the axis of said ram being tilted toward the transverse pin whereby the raising armis turned above its-- horizontal position when at right .angles to the I axis of'the rain, and whereby the load engaging end of the lifting armma'y be brought to a lower level than would be possible if the ram cylinder were upright, said position being.at,about halfway of its arc of travel.

5. 'In a fluid pressure operated jack, a truck frame, a lifting lever pivoted to said truck frame,

a pump handle pivoted to the frame on the same axis as the lever, a hydraulic unit carried by the frame and including lowering means directly beneath the common axis of lever and handle, pump means on one side of the-lowering means and raising means on the other side of the lowering means. J

' 6. In a hydraulic jack, a pivoted arm adapted to engage and elevate a load, a ram for moving the am about its pivot to elevate the load carried thereby, means for forcing fluid to the ram, release mechanism to permit escape of fluid from behind the ram, said mechanism being 10-- ram 13.- In a jack, .asubstantially leak proof hycated between said means and said ram and below the arm, andmeans rigidly carried by the pivoted arm for engaging the release mechanism when the lifting arm has reached a certain height, in order to prevent further elevation of the load.

7. In a jack, a wheeled frame, a main shaft carried by the frame, a handle pivoted on said main shaft, a load lifting arm also carried by i said shaft, and a hydraulic unit including a pump and a ram carried by the frame,-said pump and ram being in operative engagement with the handle and'with the load supporting arm for elevating the arm upon movement of the handle.

8, The device of claim 7 including lowering mechanism directly beneath the main shaft and means carried by the handle to operate the lowering mechanism at any position of the handle and means carried by the load lifting arm for independently operating said lowering mechanism at a chosen upper limit of the arm.

9. In a hydraulic jack, a body including a resand a ram for elevating s'aid arm, a pressure operated relief 'valve adapted to be opened by fluid pressure, spring-pressed means v between the pump and ram for holding said valve to its seat, said seat-being locatedbetween the pump and the ram, means for adjusting the pressure of the spring on the valve whereby said valve opens at any predetermined pressure, means for temporarily opening the relief valve when the lift- V ing arm has reached a chosen height, a manually operated lever for lifting the relief valve spring, and meansfor adjusting at will the maximum height of the lifting arm.

11. In a non-ieakable hydraulic jack, a frame,

a hydraulic unit carried'by the frame, a load lift- .ing arm, a reservoir, an upright pump cylinder rising from the floor of the reservoir, apump plunger within said cylinder operatively connected with said handle, hydraulic elevating means operatively connected, with said pump and said lifting arm, a cover for said reservoir having "am opening therethru for snugly receiving-said pump plunger, packing surrounding the pump.

and spring means compressed between the top of the pump cylinder and the packing for holdin the packing in place. 12. In a hydraulic jack, a lifting arm of channel-shaped construction having depending flanges extending beyond the web at one end, said extensions being iournaled for receiving a pivoting shaft and being parallel for part of the length of the arm but converging with the web shaft passing thru said ears and journal, a journaled lug on the lower side .and intermediate the ends of said arm for cooperating with a lifting draulic unit consisting of 'a ram cylinder, an

upright pump cylinder and a reservoir in a single tures registering with the bore of the pump cylinderand counter bored on the under side whereby said 'covercooperates with the top of the cylinder to form a packing gland for the pump.

14.v In a Wheeled hydraulic jack, a pump cylinder, a valve operating rod, a ram cylinder, a shaft supported adjacent the upper end of said rod, a lifting arm pivoted on said shaft and extending over said ram cylinder, an operating tongue pivoted to said shaft and extending over said pump cylinder, 2. plunger in the pump cylinder linked to the tongue, a ram in the ram cylinder linked to the lifting arm, an adjustable stir.- rup on said rod and camming means on said arm positioned to engage said stirrup only when the arm is at a certain angular position.

15'. In a jack, a casting for a hydraulic unit comprising a reservoir, an upright pump cylinder rising from the fioor of the reservoir, a forwardly tilted ram cylinder forming the rear wall of the reservoir, the reservoir fioor having a substantially straight bore thereinreaching from outside the front wall to the ram cylinder, a pump bore opening into said bore, the reservoir communicating with said straight bore, a valve in the straight bore and located between the reservoir opening and, the pump bore opening, a second valve in the straight bore and located between the pump bore,and the ram cylinder and a third val've between the ram cylinder and said last named valve, said first and second named valves being held in a cage fitted into said straight bore from outside the reservoir.

16'. In a jack, a pivoted load lifting arm, an arm' raising means lowering mechanism located under the pivot of said arm, said lifting arm being of channel shaped construction having depending flanges extending beyond the web at one end of the arm, said flanges havingalined bores at arm about its pivot said continuation describes an are about said shaft and engages the lowering mechanism to prevent further turning of the arm.

17. In a hydraulic jack, having aram cylinder, a pump cylinder and a reservoir, a-single continuous conduit connecting the reservoir with said ram cylinder, said pump cylinder communicating with said conduit at a point intermediate the ram cylinder and the point of communication of the conduit with the reservoir, a valve in the conduit between said points, and a second valve insaid conduit between said ram cylinder and 'said pump cylinder.

18. The device of claim 17 in which said valves are removable from one end of the conduit.

19. The device of claim 9 in which said passageway is located in the floor of the reservoir reaching from outside the reservoir to the inside of the ram, said passageway being counterbored from the outer end to form an annular shoulder at apoi'nt between the pump and said third valve,

said counter bore being threaded at its outer end, the first mentioned valve cage having a sliding fit in said counter bore and engaging said shoulder and said second mentioned valve cage having a threaded engagement with the counter bore and abutting said first mentioned valve cage to hold the same in place.

20. In a hydraulic jack, a reservoir, an apertured cover for said reservoir, a cylinder fixed within the reservoir and having its free end sub- .stantially abutting the inner surfaces of said cover, a plunger in said cylinder and extending thru and closing the aperture in said cover, the

inner side of said cover being recessed around said aperture whereby to cooperate with said cylinder top to form a packing gland. for said and a lifting lever, said lever being pivoted on' a horizontal axis located above and between said pump and ram: a single casting comprising a ram cylinder, a pump cylinder'and a reservoir, the bottom of the reservoir being integral with the bases of the two cylinders, the pump cylinder being substantially vertical and the top of the ram cylinder being tilted toward the topof the pump cylinder whereby permitting the lifting lever to move to a lower level.

22. In ahydraulic jack, a pump cylinder, a valve operating rod, a ram cylinder, a'shaft supported adjacent the end of said rod, a lifting arm pivoted on said shaft, a pump operating handle pivoted to said shaft, a plunger in the pump cylinder linked to the handle, a ram in the ram cylinder linked to the lifting arm, a cam surface on said valveoperatlng rod, and camming means 'on said lifting arm positioned to engage said sur-" face to operate the valve only when the arm is at a certain angular position.

the pump cylinder, a cover for said reservoir having an aperture in registry with the pump cylinder and an aperture between the first mentioned aperture and the ram cylinder, a valve for admitting fiuid from the ram to the reservoir, a valveoperating rod rising from the fioor of the reservoir and extending thru the second mentioned aperture, a horizontal shaft supported above the rod, a handle pivoted on said shaft and linked to thepump. a lifting lever pivoted on said shaft and linked to the ram and means on the lever for engaging said rod at a predetermined position of the lever as it moves about its 'pivot whereby to release the valve to prevent further movement of the ram and lever.

24. In a hydraulic jack having a pump and a ram; 9, horizontal shaft above said pump and ram, a handle pivoted on the shaft for operating the pump,v a lifting lever pivoted on said shaft, a

valve for controlling the ram, a rod for operating the valve, a cam surface at the top of the rod against said surface to operate the valve as the lever approaches a predetermined limit of travel. 26. The device of claim 24 in which a stirrup shaped member is adiustably connected to the top of said rod, said surface being on said member and in which said arm reciprocates in the opening thru said member.

27. In a jack, a wheeled frame, a main shaft carried by the frame, a handle pivoted on the shaft, a load lifting arm pivoted on the shaft, a hydraulic unit carried by the frame and having a pump and ram located respectively below the handle and arm, a valve below the shaft and between the pump and ram for lowering the ram, mechanism located adjacent the shaft for'operating the valve, means carried by the arm for operatively engaging said mechanism as the arm raises to a predetermined height, and means carried by the handle for engaging said mechanism at any position of the handle.

28. In a hydraulic jack having front and rear Wheels, an axle for two of the wheels, a frame consisting of two side plates supported on the front and rear wheels, a hydraulic unit between said plates and supported at one end on said axle and at the other end on said side frames, a main shaft carried in said side plates and located above said unit, a lifting arm pivoted on the main shaft and extending over said other end and handle on said main shaft and extending over said axle.

' O'I'TIS H. RECHARD.

OSCAR F. KUHLMAN.

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