US2625796A - Multispeed hydraulic power device - Google Patents

Description

Jan. 20, 1953 w. A, TRAUT MULTISPEED HYDRAULIC POWER DEVICE 2 SHEETS-SHEET l Filed Feb. 4, 1950 wen/Z A TToR/VE ys.

Jan. 20, 1953 w. A. TRAUT MULTI-SPEED HYDRAULIC POWER DEVICE .2 SHEETS-SHEET 2 Filed Feb. 4, 1950 INVENTOR. Zl/dzm/MQ-AM wen/M A rro/e/l/Eys.

Patented Jan. 20, 1953 UNITED STATES lF'EEINT :0F-FICE William A. `Trauaiiim Grove, Wis., assignor `to Blackhawk Mfg. Co., Milwaukee, Wis., a corporation of Wisconsin Applicationliehruary Li, 1950, Serial'No. 142,402

(Cl. Gil-52) ilClaim. l1

My present invention relates in general to improvements in the art of hydraulics, and relates more specifically to improvements in the construction and operation of multi-speed hydraulic rams and jacks.

The primary object of the present invention is to provide an improved multi-speed'hydraulic power applying device, whichis simple and compact in co-nstructio-n, and which is also dependable and efficient in operation.

When hydraulic rams and jacks are being operated, it is frequently desirable to be able to cause the power applying piston or plunger to travel rapidly while approaching a load and to thereafter slow down and develop the necessary power as the load is applied. This is especially the case when the movable piston or plunger has relatively .long stroke, and in any event the transfer from high to low speed travel, and vice versa, should be effected positively and automatically. While it has heretofore been proposed to provide apparatus for producing these results, these prior devices have been too complicated and unreliable in operation to warrant general use thereof, and they have also 'been relatively cumbersome and difficult to assemble and dismantle for inspection ,and adjustment purposes.

It is therefore an important object yoi" my present inventionto provide an improved two-speed ram or jack assemblage which will function automatically and effectively to convert the speed of travel of the power applying member thereof, from high to low and vice versa.

Another important object of the invention is to provide a simple and reliable system fortransforming the speed and power of a` ram or jack plunger from one value to'another, with the aid of simplied and automatically functioning control valves.

A further object of this invention is to provide an improved twin-speed hydraulic power unit which is durable and exceedingly compact in construction so that it may be-conveniently manipulated in cramped quarters and utilized for diverse purposes.

Still another object-of my invention is toprovide an improved multi-speed hydraulicpower device which may be readily assembledand dismantled for inspection, ,wherein variousvparts are conveniently accessible for adjustment, and which may be manufactured land sold at moderate cost.

.These and other objects and advantages of the invention will be apparent from the following detailed description.

A clear conception of the various features constituting my present improvement, and of the construction and operation of a ram and a jack assemblage embodying the same, may be had by ,referring to the drawings accompanying and forming a part of this specification whereinlike `reference characters designate the same or similar parts in the various views.

Fig. 1 is a fragmentary central longitudinal section through a typical two-speed long stroke hydraulic ram built in accordance with the invention.

Fig. 2 is a central longitudinal section through the b-ase of the ram shown in Fig. '1, the section having been taken along the line 2-2 of Fig. 4;

Fig. 3 is a central longitudinal section through the ram base, similar to that of Fig. 1, and taken alo-ng the line .3-'3 of Fig. 4;

Fig. 4 is an end view of the ram'base looking toward the flow control valves and ports, and with the high-speed .piston and the lowspeed cylinder v omitted Fig. 5 is a transverse section through the same ram base, takenalong theline 5-5 of Fig. 3;

4Fig. 6 is another transverse section through the ram base, taken-along'the line .6 6 of Fig. 3;

Fig. '7 is a central vertical section through a typical high-lift two-speed hydraulic jack also built in accordance with the invention.

Fig. 8 is a part sectional side elevationoi the jack assemblage shown in Fig. 7, looking toward the pump thereof;

Fig. 9 is a transverse section thro-ugh'the auxilliary base of the high-speedpiston of the jack; and

Fig. l0 is a reduced somewhat diagrammatic top View of the jack shown in Figs. 7, 8 and'9.

In accordance with my present invention, I provide `a base member having a main liquid supply communicable with'a high pressure source and an auxiliary vlioluid supply connecte-d to a low pressure liquid source, the base al-so having a rigid yhollow piston coasting with the bore of a plunger which is confined within a cylinder secured to the base and cooperating with the fixed piston to produce an 4annular space within which the plunger is reciprocable by liquid .flow controlled by means of a unique. series ci valves ali confined within the base, and `while the improvement has been shown and vdescribed as beingadvantageouslyapplicableV to oil actuated rams and jacks of specific types,pit' is not; my desire or intent to `unnecessarily, limitzthe scope or utility 3 'of the improved features by virtue of this restricted disclosure. It is also contemplated that specific descriptive terms used herein be given the broadest possible interpretation consistent with the actual disclosure.

Referring to Figs. 1 to 6 inclusive of the drawings, the improved two-speed hydraulicram shown therein, comprises in general a cylindrical base I4 having therein a high pressure liquid inlet and exhaust port I5 and a low pressure liquid supply port I6, and also having a rigid hollow piston I1 projecting therefrom; a cylinder I8 having one end secured to the base I4 and surrounding the fixed piston I1 to provide an annular elongated space enclosed at its opposite end by an annulaicylinder head I9; an annular plunger reciprocable within the annular space and having a rod 2l passing through the head I9, the plunger and rod assembly being provided with a central bore 22 snugly but slidably embracing the xed piston I1; and a series of automatically functioning valves all-mounted within the base I4 for controlling the ow of liquid to and from a small high speed plunger displacement chamber 23 located between the inner end of the bore 22 and the free end of the piston I1, and to and from a larger low speed plunger displacement chamber 24 disposed between the base I4 and the adjacent end of the plunger 29. Y

The base I4 may be formed cylindrical and of a single-piece of metal, and has a pair of pivotal suspension lugs 26 at one end and internal and external screw threads 21, 28 at its opposite end; and the main supply and exhaust port I5 may be connected by a tube 29 with a suitable source of liquid under pressure such as a pump having the usual manually operable relief valve such as the valve 68 of Fig. 8, for returning liquid to its liquid supply reservoir, While the auxiliary port I6 may be likewise connected by a tube 39 with the liquid reservoir from which the pressure pump obtains its liquid supply. The liquid supply pump may either be hand operated or power driven, and when the latter type of drive is utilized a suitable control valve for regulating the speed of travel of the ram plunger 20 should also be provided in a well known manner. The piston I1 is detachably but rmly secured to the screw threads 21 of the base, while the cylinder I8 is likewise secured to the screw threads 28, and both of these tubular elements may be formed of standard tubing of proper length. The cylinder head I9 may also be detachably secured to the cylinder I8 by means of screw threads 3i, and the plunger rod 2I may likewise be formed of standard tubing welded or secured to the plunger body 20, or these plunger parts may be formed integral with each other. The outer end of the plunger rod 2I may be provided with a re-enforcing fitting 32 welded or otherwise attached to the tubular rod, and suitable O-type packing rings 33 or the like, may be interposed between the piston I1 and the plunger, and between the latter and the cylinder I8 and head I9, as shown in Fig. 1. The exterior of the plunger rod 2I is also slidably embraced by a stop collar 34 for limiting the outward movement of the plunger 20, and a normally plugged bleeder passage 35 may also be provided at the outer end of the hollow rod 2|.

The small or high-speed displacement chamber 23 is in open communication with the main liquid port I5 at all times, through thehollow piston I1 and a central. duct 31 in the base I4;

4 while the 'larger or low-speed displacement chamber 24 is provided with three automatically func tioning ow control valves 38, 39, 4B which may be designated as the suction valve 33, the high pressure supply and unloading valve 39, and the release valve 40 respectively. The suction valve 38 is located in a straight passage 4I connecting the auxiliary liquid supply port I6 with the chamber 24, and is adapted to open automatically whenever the plunger 29 is moving rapidly away from the base I4 so as to permit free ilow of liquid into the chamber 24 from the receiver through the auxiliary port I9. The high pressure valve 39 is located between a straight passage 42 communicating with the liquid supply duct 31 and another rather irregular passage 43 which communicates with the displacement chamber 24, and this valve 39 is urged toward its seat by a compression spring 44 coacting with an adjusting plug 45 and is provided with a surlrace 46 exposed to liquid pressure within the duct 31 and port I5. The release valve 49 is located still another straight passage 41 which con- 'nects the large displacement chamber 24 directly with the main port I5, and this valve is normally 'seated by a compression spring 48, coacting with a. hollow adjusting plug 49 but is adapted to be opened by'liquid pressure from within the chamber 24. A drainrconduit 50 which is normally sealed by the high pressure valve 39 is also provided, and all of the ports, ducts, passages and conduits may be formed in the base by simple l'drilling operations and have their dead ends sealed by screw plugs 5I.

During normal operation of the improved longstroke ram unit shown in Figs. 1 to 6 inclusive, and assuming the plunger 29 to be in retracted position, when liquid such as oil under pressure, is admitted from a pump or other controllable source through the tube-29 to the main port l5 the admitted liquid flows without obstruction through the duct 31 and the hollow fixed piston I1 into the smaller displacement chamber 23. If the plunger 29 isunloaded, the liquid thus admitted to the chamber 23 will cause the plunger 20 and its rod 2| and tting 32 to travel forwardly or away from the base I4 at high speed, and this rapid forward motion of the plunger 20 tends to create a vacuum in the larger displacement chamber. 24 thereby unseating the valve 38 by suction and permitting liquid to ow from the storage reservoir through the tube 3), auxiliary port I6 and passage 4I soas to maintain the chamber 24 lled with liquid.

When the forwardly advancing ram plunger 20 engages an obstruction and becomes loaded, the incoming liquid quickly builds up pressure "within the main port I5, duct 31 and passage 42 suicient to open the pressure actuated valve 39 and to thereby admit high pressure liquid through the passage 43 into the larger liquid lled chamber 24 as well as directly to the smaller chamber 23, thereby subjecting the ram plunger 20 to high pressure liquid throughout its entire area. The plunger 20 will then travel at considerably reduced speed and its forward travel may even be arrested while holding the load, and the suc- Ytionvalve 38 will be closed and will remain seated while the plunger2IJ is subjected to loading so that no liquid can escape from the chamber 24 to the auxiliary port I6 and reservoir through the tube 30.

During the forward travel of the ram plunger 29 the stop collar 34- will ultimately engage the cylinder head I9 to positively arrest the plunger travel, and 'when iit "becomes desirable to 'retract 'the plunger $26,'this may be donejby manipulating vthe Vusualmanually loperable, by-pass or relief -p ressure actuated valvev39, "so that this valve will remain open. But when the pump pressure is by-passed to relieve the pressure in the supplyA pipe 29 thev valve Y'Ill'.l will open to quickly release liquid fromthe large displacement chamber 24 directly to the main port I5 through the passage 42. All liquid, is thusautomatically released and permitted Ito escape. 'from 'the displacement chamber 24 during retraction of the ramplunger 20, thus leaving this chamber free to receive a subsequent charge of Vliquid from theportI5.

The load acting uponthe ram plunger 26 and the .pressure created by the pump 'thus function to automatically ',actuate the valves 38, 39, 40 in accordance with variations in pressure existing within the larger displacementchamber 24. and the opening and closing pressures of the valves 39, 46 may beV quickly and conveniently varied by merely unscrewing the cylinder I9 from the base I4 and by thereafter adjusting the screw plug 45, 49, respectively. While the main port I5 serves to admit and release liquid to and from both displacement chambers 23, 24, the Vauxiliary port I6 only admits liquid to the larger chamber "24 duringhigh speed forward travel of the ram plunger 25, since 'the suction valve 33 closes immediately when this plunger is loaded,so vthat the sole function of the valve 3,3 is to maintain the displacementY chamber 24,v iilled with liquid while high speed operation'is being' effected. The disposition ofjall or lthe valves 33,` 39, 46 and the various liquid conducting passages within vthe base I4 obviously provides an exceedingly 'compact unit in which all concealed parts are readily accessible.

Referring toA Figs. 7 to 10 inclusive ov the drawings, the improved two-speed hydraulic jack shown therein, comprises in general a. cylindrical base member 54 having therein a high pressure liquid inlet and exhaust port 55 and a low pressure liquid supply port 56, and also having a rigid hollow piston 51 projecting upwardly therefrom;

a' cylinder 58 having `its nlower end snugly embracing the member 54 V and surrounding Athe fixed piston 51 to provide a vertically elongated annular space enclosed `at its upper end by an annular cylinder head 59; an annular plunger 69 reciprocable within the annularspace and having a rod 6I passing through the headY 59, the plunger and rod assembly being provided with 'a central bore snugly but slidably embracing the fixed piston 51; a main base 62 secured to vthe lower endof the cylinder 58 andfclamp'ingly engaging the base member 54 to irnily hold the latterY and the piston I51 in xed position; a liquid supply reservoir 63`fsec'ured to the vbase 62 and coacting with the cylinder head 59 to provide a liquid conning chamber surrounding the cylinder 58; a manually operable pump 64 also mounted upon the base62;rfand a plurality of valves for controlling the flow of liquid from the reservoir 63to' and fromv the high speed vpiston displacement chamber' 65 and to and'from the low speed l'-piunger" displacement chamber 65. The base62"of the jack 'may 'be `of relatively usual manually:operablejby-passior release vvalve ,68 for effecting loweringofthejjacli"plunger rod 5I, and the rpressure v supply "pumpl64 has ya manually operabie piston vISi vreciproce-ble krwithin a cylinder 16,'and is 'provided withjan inlet valve 1I for controlling l`the` Withdrawal of liquid through a suction vconduit 12 from the supply reservoir 63 andfwithfa' spring pressed `discharge valve 13 for likewiseicontrolling the delivery of liquid under pressure through another Vconduit 14 to a supply chamber15 located beneath the base member 54, seer Figs. 7 and 8. The cylindrical base member 54 may be firmly but detachably clamped -within the cylinder 58 by attaching the lower Vcylinder rend" to the main base 62 with the aid of vscrew threads as shown, and the cylinder head 59 maybe likewise attached to the upper 'extremity' of the' cylinder 58, while the piston 51 may also be rrigidlyattached to a central projection on the base member 54 either by screw threadsl or otherwise. 'The hollow piston 51, cylinder 58, and reservoir 63 may all be formed of standard tubing, and suitable packings 16, 11, 18 should be provided between the piston 51 and plunger 60, between the plunger and the cylinder 58, and between the plunger rod 6I and the cylinder head 5,9, 'while va bleeder passage and hole 19 should also be providedv in the upper portion of the cylinder wall.

The small or high-speed displacement chamber 65 is in constant open communication with the main liquid supply port 55 and with the chamber 15 through the hollow fixed piston 51; while the larger low-speed displacement chamber 66 is provided with three automatically functioning flow control ValvesY 8|, 82, S3 all of which are shown in Fig. 9 vand may be designated as a suction valve 8|, a high pressure liquid supply and unloading valve 82, and a release valve 83. 'The spring pressed suction valve 6I is located in a series of passages 84 communicating with the port 56 so as to directly connect the liquid supply reservoir 63 with the large displacement chamber 66, and the valve 8| is adapted to open automatically whenever the plunger 60 is `being elevated rapidly so as to permit free flow'of liquid from the vreservoir 63 into the chamber 66 through the passages 84 .and port 56. The high pressure valve 62 is interposed between the supply and exhaust port 55 and a lpassage 85 leading into the large chamber 65, and this valve 82 is urged toward its seat by a spring 66 and is adapted to be opened automatically by high pressure established within the chamber 15 and port 55. The release valve 83 is located in still another passage 81 connecting the larger displacement chamber 66 with the pressure chamber' 15 and this valve 63 is normally seated by a compression spring 88, but is adapted to be opened by liquid pressure created within the chamber 66 by the descending plunger 60 and rod 6|. The valves 8|, 83 are all confined within the member 54 by screw plugs as shown, and the relief valve :66 is adapted to control the 'releaseofv liquid from the chamber 15 to the supply reservoir 63 through a conduit in a well known manner.

During normal operation of the improved high-lift jack shown in Figs. 7 to 10 inclusive, `and assuming the plunger 60 and rod 6l to be in lowered position, when the pump 54 is operated to force liquid under pressure into the chamber 15, pressure liquid will flowV directly from this chamber through the lport 55'and hollow piston 51 without olc'nstruction linto the small high-speed displacement chamber 55, and will thus cause the plunger and rod 6I to lrise rapidly when these elements are unloaded.V This upward travel of the plunger 60 will tend to create a vacuum in the larger low speed displacement chamber 66 and will unseat the valve 8l by suction thus permitting liquid to now freely :from within the reservoir 63 through the passages 56, 84 so as to maintain the chamber 66 lled with liquid during high speed rising of the plunger. .l

When the upward motion of the plunger 65 and ro-d El is obstructed to load the jack, liquid pressure promptly builds up in the passage 55 suicient to open the valve `82 against the action of the spring 86, and'liquid under high pressure is then simultaneously admitted to the small displacement chamberY 65 directly through the hollow piston l and-to the larger displacement cham- -ber 56 through thefpassage 85, thereby subjecting the plunger 60 to high pressure throughout its entire area. The plunger 60 and rod 5I will then travel at considerably lower speed while loaded and this travel may even be arrested when supporting the load, and the high pressure within the larger chamber 6B will close the valve 8i while the high pressure in the chamber I5 will also maintain the automatic release valve 83 in closed position, so that no liquid can escape from the chamber 66 during loading of the jack.

When it becomes desirable to lower the plunger 66 and its rod 6|, it is only necessary to open the relief valve 68, thereby connecting'the pressure chamber 'i5 with the supply reservoir 63 thro-ugh the return conduit 9i). opened only slightly, the downward motion of the plunger 6U will beyslow and the unloading valve 82 will then remain open until the pressure exerted by the spring 86 exceeds the liquid pressu-re tending to open this valve, whereupon the release valve 33 will open and will ultimately allow all of the liquid to return from the displacement chamber 55 to the reservoir 63 at relatively higher speed until the plunger rod 6| has been fully lowered or retracted.

The improved twin-speed jack thus also'functions to automatically actuate the control valves 8l, 32, 83 in accordance with variations in pressure existing in the supply chamber 15, and the opening and closing pressures may be regulated by properly manipulating the pump 70 and the by-pass or relief valve E8 and by varying the pressures exerted by the springs upon the un loading valve, Since the displacement of the pump plunger 69 is relatively large compared to that of the fixed piston 51, it will require only a partial stroke of the pump to advance the plunger 6i) and rod 5| a considerable distance at high speed, thus insuring quick action; and by opening the relief valve B8 to its fullest extent the movable plunger 60 may also be quickly retracted. While the main liquid port 55 serves to supply and release liquid to and from -b-oth -displacement chambers 65, 65, the auxiliary port 56 only admits liquid from the reservoir 63 to the larger displacement chamber 66 during high speed upward Atravel of the rod 6|, since the suction valve 8| closes promptly when the jack is loaded. The automatic valves 8l, 82, 83 are all readily accessible by merely unscrewing ,the cylinder 58 from the main base 62, and while these valves may be disposed directly in the main base 62, their disposition within the small base member 54 provides a compact assemblage which can be readily machined, assembled Vand dismantled. i

If the relief valve 68 is l Fromk the foregoing detailed description it should be apparent-that I have in fact provided a simple, compact and durable multi-speed hydraulic power system which is readily applicable to either rams or jacks, and which is automatic and efcient in operation. In both of the typical structures illustrated, the unit is provided with a main high pressure liquid supply and discharge line and with an auxiliary low pressure liquid supply line which merely maintains the low speed displacement chamber lled with liquid While the high speed displacement chamber is in action to rapidly advance the plunger rod. In both assemblages the high speed plunger displacement chamber is in open communication with the liquid pressure source, and admission and discharge of liquid to and from the low speed ldisplacement chamber are controlled by three automatic valves, while both displacement chambers are simultaneously subjected to high pressure when the plunger is loaded.

It should also be noted that by providing unloading springs i4, 86 of different strength, the improved ram or jack may also be utilized to lift light and heavier loads in succession, so that the invention is not confined to units wherein the plungers are merely subjected to either no load or full load. By coniining all of these automatic valves in a relatively small base member to which the cylinder is detachably secured, a compact unit results While the valves are also readily accessible for inspection and adjustment. The improved devices can also be readily and accurately machined with the aid of simple tools, and the parts may be conveniently assembled or dismantled thus providing structures which may be manufactured and sold at moderate cost for diverse purposes.

It should be understood that it is not desired to limit this invention to the exact details of construction and operation of the typical ram and jack, herein specifically shown and described, for various modifications within the scope of the appended claim may occur to persons skilled in the art.

I claim:

In a two-speed hydraulic jack, a cylindrical base member having separate high and low pressure liquid passages therein and also having a rigid hollow piston projecting therefrom and constantly communicating with said high pressure passage, a tu-bular cylinder secured to and embracing said base member and surrounding said piston to provide an annular space, an annular plunger reciprocable within said space and having a bore slida-bly cooperable with said piston, the free end of said piston coacting with the a-djacent end of said bore to provide a small plunger displacement chamber and the end of said plunger facing said base coacting therewith to Iprovide a larger plunger displacement chamber communicable with both of said passages, a suction pressure actuated valve conned within said base for permitting free iiow of liquid under loW pressure from said low pressure passage to said larger chamber whenever liquid under pressure is being admitted from said high pressure passage to said small chamber to rapidly advance said plunger while the latter is unloaded, an adjustable pressure actuated valve also conned within said base for admitting liquid under high pressure from said high pressure passage to said larger chamber to simultaneously close said suct1on valve and to advance the plunger at slower speed when loaded, and another pressure actuated valve conned within said base for releasing liquid from said larger chamber to said low pressure inlet Whenever said plunger is being retracted.

` WILLIAM A. TRAUT.

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

UNITED STATES PATENTS Number Name Date 67,719 Burr Aug. 13, 1867 Number lo Number Name Date Stevenson May 22, 1923 Smith Sept. 8, 1925 Hottel Jan. 6, 1931 Brandenburg Feb. 16, 1932 Stephens July 28, 1936 Page May 26, 1942 FOREIGN PATENTS Country Date Great Britain Aug. 30, 1928 Switzerland Sept. 2, 1940

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