US2095286A - Hoist - Google Patents

Description

H. J. RIACH Oct. 12, `1`937f HOIST Filed Nov. so, 1931 s sheets-sheet 2 i Patented 12,` 19:37 i i i `This invention relatesto a hoist such as is emthezriygidity and strength to the hoisting body and ployedto raise motor truck bodies. 4and the like, Y supporting means which isvery desirable. y `or `for any otherfhoistingvpurposeWhere it is de- `My` unitary l.hoisting mechanism does not res iredHto employasimplified mechanism having quire rollers `or trackskbeneath the body to 'be i 5caypowe'rfu1-1ifting capacity andwigh `@wrm-,L11 numi, hoisted butis connected by'levers lan@ operating 5 ber 4onparts whichpare arranged together solas to erpossiipleed meeDSSOeS t0 give e drei'f'lifting operate in a mannerto give more efficient service.- DreSSllIeiO, the Operating links" S0' as t0 raise the A feature@ the inyeriticn resides in lproviding bodylof themotor truck in anweicient `riianner. `a, pipeless hoisting mechanism so as to obviate all .This heistinglmeehenism may be mede With a unnecessaryaoints which may` cause trouble ci?` Single vlorl-iing` eililide` Ol With twin Working which through yibration wcuidbecome defective i` Cylinders, Oras mamycylinders` as may be de.- and leak orbreak. This is` an important featurev Sired, and by `lflfleans of the peculiar unitaryv con- 1 because hoists ofthis nature `whenused onrmotor `Silleiieli PTOVde e lel'ge reservoir chamber for w trucksv are subjected to heavy dutyand the vibra-V the'Oil 01` fluid used'inythe operation of the "Work-` 151 tions of the truck in `traveling over the road puts iig` `r'iiiidenig' .Furtheri the?? are n0 extern@ 15 a severe `strain oncthe conec'itirig` parts ofthe iiiiii Poiiiiectioiis tothe nipifrtiiigpliiiiip foi' the "hoistsv and, I `have designed thislymechanism` `to` hoitiY s unitand ihe'samemay be Opemted `withl overcomefxthese defects `hyjprovidi'ng a pipeless ahigi Qi'liQWiliisSuiey x .i y y y hoisting mechanismmwhich'gis .compact and de- IiilPiOViCiing a iiQiStiiig mehnisiii formoioi y `i signediinla manner to vgivethe Ibest eiciency'in', iiil'iiii` bodies i0 tiii" the boiies. 'S0 that tiie con 20` .1 operation, i .y A p y i i l teiits'of'iiii@ ,Asa'iiiejmay be dumped Teadiiy it is AA further `feature offmy invention resides ina im impoitaiit iiiiiiiii'e i0 iii'OViFie iaige" iiisioiiaiea' lparticular.constructionwherein I place the opery if it is Possibles as to redi the 911 pressure tuig cylinder Within a; casing orlhousing which without unnecessarily increasing the height or may beltermed `the`1`otitsidef cylinder or casing.

depth f the' hoisting unit;l This I accomplish l y i `with my particular construction ofhoisting mech-V Thns the casing or outer cylinder `providesa reser mism, thereby maintaining a mimmumhh-eight voir aroundrthe working cylinder, glvmg an in-l b t i l @th "h l i f1 ,ld be tto i if th y l creasedcapacitywto, thezreservoir orlowpressnre bedlweer/I tss s rahmeg'nd ,commi C? une; "jcompartment ofthe hoist unit,withoutmaterially` 1 y'i ly 012 inglnc l glsmf i) W. `inceasingthe outer dimensions andovercoming n a' Sng eun nc u ng e pump an comic' 30 the necessity of `having a separater-tanker comtiolfs fromlthepump ,to sie operating Working parti-nent remotely positioned to the *working cyl-i cylinder or cylinders and by means of aparticu inder;v Suchhoisting mechanismsas havevbeen lig; boglglpflisigdilgr:gglfgl` y used heretofcrewhere thegreservoir wasmplaced` L ith h i ti nit `h1 h `t t i' `th Y `remote tothe Working cylinder gave considerable W" my o s msu W c opera es o ra se e 35 trouble and havebeen hard to mount upon the dumpmg bogithout tracks" Tenersi ori "offset l variousmotcrwtrucks` Iused for hoisting purposes, rtlfaig it fvelreyyrrig gnlfccooo :that isgtheih'oisting ofthe bodiesandlthe like. dut'ytowhich M-,tigappne` z i i 40 letseicahf"fh *Features and im f' prima imitan 4 cylinder Weremnot Comct and required pip :Ivillbe fulllyx"4 and clearly set `forth in thespecical inand' ms."-' l connections or long` cast manifolds which have olnth rwings forming jpart this specificaalso givennconsiderable trouble inikeeping the tfon; l l l 1 sameinlopei'ativeciiiiiii'ioii and Oii tiiit- Y "Figure 1 is a plan view of my hoisting `unit and 45 jf'Itwisaffeaturetojprovideahoistingl-rnechanism the supporting "frame which carries thev same. which isloffa unitary natilleelidsb @Ohipectes '00 showing" diagrammatically` :the relative position g'gvice asmlalllrurthmsiting'devce vllimlvhmalily gli ofthe vhoisting nitahd ftraml to the body or l y ce 1n cose `mens ons an "w c w1 Supporting mem erso a, ruc y "3 `o readily underthe body'which isfto .be hoistedby `Figure; 2 is a, side View Ufjmy hoisting meel-1a.` 5o this mechanismpand` in fact, which may not ex" nism, showing a portion of the truck body and ceed in depth dimension the cross holsters which frame to which the unit is attached, alsoshowing eerlyfihehostingbody *With thiSeOmDaet urii- `in dotted linesthe relative hoisting position of `tary hoisting device itis not necessarytocut the part-s.

'Y away l thefcross holsters and thereby I maintain Figure 3 is a section onithe ilne 3?-3 ofFigurerl. 55`

Figure 4 is a section on the line 4-4 of Figure l, in the direction of the arrows.

Figure 5.is a section on the line 5-5 of Figure 1, in the direction of the arrows.

Figure 6 is a similar section to Figure 4, showing a single working cylinder instead of twin cylinders.

Figure 7 is a front end view of the pump portion of my hoisting unit.

Figure 8 is a section on the line 8-8 of Figure '1.

Figure 9 is a section on the line 9-9 of Figure '7.

The operating cylinder A of the unitary hoistying mechanism is supported by the longitudinal channel iron members I8, the ends of which rest on the transversely extending angle iron members I I and are secured thereto by spot welding or bolting the same rigidly together. At one end of the cylinder A the angle iron member I3 supports the same directly above the transverse angle member II, while at the other end of the cylinder A the transversely extending shaft I4 is supported in the bracket members I5 and these brackets are secured to the longitudinal channel irons I0 on either side of the cylinder A. In this manner the cylinder A is rigidly and firmly supported on the angle frame members of the hoisting unit. l

The operating hoisting cylinder A is thus carried by the frame made up of the longitudinally parallelly extending members II) and the transverse parallelly extending members II. This frame is adapted to rest and be secured in a suitable manner to the bed or longitudinal Vframe members I6, only a portion of which is shown, and which form the chassis frame of the motor truck or other device to which the hoisting mechanism is attached. With this frame the hoisting mechanism is firmly and substantially carried upon the members I3 of the truck to form a strong and substantial supporting base portion to hold the hoisting mechanism in place and to distribute the hoist force in a desirable manner to the bed or frame portion ,I6 of the truck which is an important feature, as will be more fully hereinafter set forth, giving advantages to the..

construction of my'hoist and the arrangement of the partsover hoisting mechanisms that have been used heretofore in connection with motor trucks and dumping bodies.

The cylinder A is formed with an outer casing I1 which extends between the end plates I8 and I9 and may be formed of sheet material of the desired gauge with the same detachably secured with the end plate I8 as illustrated and welded, or otherwise securely attached to the end plate I9. Within the cylinder casing I1, I provide a pair of operating cylinders 20 formed of tubing of the desired gauge so as to provide working cylinders which are adapted to receive the operating pistons 2I. 'I'he cylinders 28 are formed with a head portion 22 on one end, which is in the form of a collar member, said collar member 22 holding the cylinders 20 concentric with the piston rod 24. This collar 22 is adapted to extend into the opening 23 formed in the end plate I8 of the cylinder A and is secured thereto by a fluid tight joint so as to close the end of the master hoist cylinder A and to form an end portion for the cylinder 20. Each of the cylinders 20 are constructed in this manner.

The piston 2I isY provided with an operating rod 24 which is secured to the piston in a. suitable manner and extends through the end 22 to the operating yoke 25 which is keyed or otherwise secured to the outer end of the shaft 24 to connect the shaft rigidly to the operating yoke 25. The inner ends of the cylinders 20 are secured to the plate I9 by welding or otherwise attaching the inner ends of the lcylinders 20 to the plate so as to form a uid tight joint between the wall of the cylinder 28 and the end plate I9.

The operating pistons 2I of the working cylinders 20 are formed with a packing groove 21 in which a series of leather or flexible washer packing rings 28 are positioned and held against disengagement bymeans of the plate 29 on the end of the piston 2|. The plate 24 is held in place by screws (not shown) or by any other suitable means. 'I'his provides a very effective packing having a very durable nature and also providing an emcient packing means for the operating piston 2I. A relief valve 30 is carried by the piston 2I and is held normally closed by the spring 3I, while the outer end of the valve rod 32 extends beyond the spring so that when'the piston 2I reaches a point adjacent the end 22, the end 32 will strike against the cylinder end 22 and open the valve 30 to relieve pressure from beneath the piston 2I and providing circulation through the piston 2I, through the ports 30' into the reservoir 33.

'I'he master hoisting cylinder A is formed with one or more working cylinders such as 20, within the casing I1 and the compartment or space formed around the Working cylinder or cylinders 20, such as 33, provides a reservoir chamber for oil or other fluid which is adapted to be used in the master hoisting cylinder in its operation. A drain plug 34 is provided in the lower side of the casing I1 to permit the draining of the iiuid from the reservoir chamberv 33. The master hoisting cylinder-may be formed with small adjacent or twin cylinders 28 as illustrated in the section of Figure 4, where the cylinders 28 are placed parallel with each other so that the master cylinder A may be comparatively fiat in its height or the depth of the same from the top to the "bottom, or a master cylinder A may be formed with the working cylinder concentric with the casing I1' as illustrated in the section in Figure 6. In this last construction one working cylinder 28' is positioned inside of the casing I1 of the master cylinder. The operations and function of this master cylinder A is the same excepting there is only one operating cylinder such as 20 instead of two or more such cylinders.

My `hoisting mechanism is provided with a manifold block 35 which is secured to the end plate VI9 of the master cylinder A through which the shaft I4 extends and which is adapted to provide the manifold connection with the bearing block 36 and the-gear pump 31. This manifold block 35 supports the operating or control valve 33 for the master cylinder A, the valve being positioned Within the casing portion 39 which is bolted to the manifold 35. The block 36 forms a bearing for one endof the shafts 40 and 4I which support the Working gears 42 of the gear pump 31. Thisblock 36 may be-made of bronze or other suitable metal to form a suitable bearing for the ends of the gears 42 and shafts 4U and 4I. A cover 43 formed of bronze or other suitable metal adapted to provide a good and substantial bearing rifamfold as yas 4illustrauaa in a, and nuts 45 holdingtl're cover.f43 firmly in" place aoeae'se the against the body of ftiie gearpump 31. A

The shaft 4| extends through Vthecover to i provide a working` e`nd4lf to whichl a universal joint 45 may beconnected and which may be operated by the 'drivingshaft' `so` as" to operatethe gear purnp` 31 when litis desired. I providea packing gland 48ofl Wpulia nature extending around` the working end 4|"of the shaftll" and i thefpacking 49 inthe gland maybbeadjusted by `means of the threaded plunger bolt 50;Y This providesiasuitable means offorminga packing providing hydraulic" pressure for operating` the i aroun'dithe workingendof'thejshaft 4| so as to permit fthe"f'gear pump 31fto t operate 'eiliciently without `leaking aroundfthe outer end of the shaft.` i 4| or to take up'ordina'ry wearing of'the'shaft i i endbeering to provide a' better. .efficiency vfor the gear' pump for alongerperiod of time. i

The gears `42Ua1re heid between the block 36 .and the cover 43 4so thatthese parts, namely," the block 3|ifan`dthefcover` l43, form bearings `for the side 'walls of the" gears 42.5". Thisprovidesa workingltightjoint'sothatthe gears`42 maybe operated as thegear pump 31 to provide theldesired mud pressure to Vme pastorie 12|y @fthe eyimae'rs zo. With "a gearj pump of this nature', considerable pressure `maybe built up by using a iiuid` such as oil or other` sultable fluid `means which provides a lubricant for the pump as well asfthejmeans of pistons 2|.` The structure of the pump "31is of a simplena'ture and the partsthereof may beread- 35, ilyreplaced Las well as the bearing parts `38 `and 43.

This-provides a pump `means `for my hoisting `device wherein the parts mayueasilybe replaced as they become worn out, or for `any other reason,

a feature which is highly desirable ina device of i this character. Hoists for dump bodies for motor trucks, are subjected to considerable use 'and it `will be apparent that in asimple construction of r the manifold'i35, together withy the quickly land readily replaceable!parts` 36, y31" and"43`, that I provide a very desirablestructure wherein all of the partsare of a simple yet practical naturel i ,Thedriving shaft41sfor the pump31 maybe connected to any suitable source of power, such as a powertake-oil mounted on the truck transmission (not shown). or may be driven by any other suitable means tooperate thegear pump 31 to draw oil from the reservoir chamber33 through the passageway lwhichisformed in the end plateV |-9,\then through the passageway 52 formed infthe manifold 35 and through the passageway 53 lnannteuwin the bearing mock as to the pump 31. Asthepump 31"operates,it will force oil awayfrom the `saine through the passageway54 formed in the block 36 againstthe Vspring ball check'55 which is supported inthe manifold 35` and is adapted to operate against avalve seat formed Vin the block 3,6. y

In the operation ofthe gear pump 31 `to operate t l the pistons 2|, thevalve38yisturnedinto closed position. The fluid pressure lcoming from` the pump will, open the check valve 55 and permit the fluid to: pass through the passageway 56 and w i through `the openings 51 directly against `the pistons \2| inthe'gcylinders 20, operating `the pistons tomove thepiston rods 24 outwardly and thereby operating theyoke 25. The valve138is "illustratedin \Figure13 .in Vopen position. When it is desired tooperate the pistons as just 'de-: scribed, this valve is first turned into closedposition so asto shut offtheby-pass passageway 53 lformed in thecasing. which also closes the bypass passageway 59 which connects with thepassageway 58 through the valve 38.` The passageway 59 is formed inthemanifold` and connects with: the passageway 60 in the plate lleading into thereservoir chamber 33. a i Thepassageways 5| and'll are formed in the plate I9 between the cylinders `20` andthe passageway 5| Aprovides an outlet totheintakeend of the pump 31. Thepassageway 30 provides Aan inletpassageway for the fluid` or oil when the piston 2 isoperatedv toward the end` plate.. I9. After the `pistons 2| havebeenmoved toapoint adjacentthe vend 22 and it isfdesired to return tbemto the position illustrated in Figure-3. the valve 33 is placed in "the position i illustrated in Figure 3 and thereupon" pressure on theyoke25 will pusiif the piston 2| toward the end.' |9,"forc "ingthe oil Vunder thejpiston in the cylinder 20 out of thepassageways 51 through the passageway 56 around the' check 55 into the passageway 53 through the valve 38 and throughthe passagei way 59`and through the; opening 6|lrback into the reservoir vchamber 33t. -f i. i u

Withthis master hydraulic hoisting unit Aa very i desirable constructionis `provided 1,wherein awmaximum reservoir is formed about thecylinders 20` and by the increased piston area permits alower working pressureH to beemployed to'operate the hydraulic hoisting unit.` There are no outer connecting pipes, allof thepassageways are contained'within the unit andthey `are so directly connected and closelyassembled as to provide a more eilicient hoisting device. 'Ihis compact hoisting unit" provides a primary feature of importance and advantage in my: yhoisting device.

I provide a filler plug 59f leading into the passageway 59 whichprovide's an easy means-for filling the oil intothe hoist in servicing the cylindex-A and the pump 31. The location of the plug 59' "prevents filling the hoistcylinder A with toomuch 01h-allowing for displacementfof oil bythe pistonrods`24: i i

My hoisting`unit,` owing-to its compact nature and the fact that it may be mounted to lie hori- "zontally with itsframe made of the members IIJ and on theframe portion such` as I6 ofv a motor truck, is particularly adapted for hoisting dump bodies such as are used ontrucks. The 'drawings illustrate diagrammatically only a portionof the motor truck, such as the'frameporlongitudinal holsters 62. The longitudinal bolsters 621aresupportedvby the bracket65 which is pivotally,` mounted at 66 on the frame members I6 and Arear transverse angle iron "I I." This pivotally supports the bolsters 62 which carry the dump 63 through the cross holstersI B4. Thus thembody 5321s `pivotally"'mounted to the .frame |`5fof the l'notortruck.

The' pivotal mounting `at '66 its virtually4 adjacent one endof the master hoisting cylinder A and on either 'side of ,the same. The compact nature of my hoisting device with its comparatively flat master hoisting cylinder A permits the same .tot in close quarters beneath the d ump body 53 and without lnterferefncewith any of the parts 'of Vthe truck, such as thecross members of the frame, or rear axle. This is an important feature as will be more fully set forth.

The shaft I4 carries a pair of drop forged arms v61 and these arms are free to pivot on the shaft I4. The arms 61 are of a peculiar shape and are pivotally connected at 68 to operating links 69. The links 69 are connected on one end to the shaft-10 which is supported on its ends by brackets 1l. These brackets are connected to the channel members 12 which extend above the longitudinal frame members I0 and which are adapted to be secured to the cross bolsters 64,0! the body 63. w'Ihe arms 61 are formed with a shoulder portion 13 against which the short link 14 rests when the parts of the hoisting mechanism are in the position illustrated in Figure 2. One end of the link 14 is pivoted at 15 to the arm 61 and the other end is pivotally connected at 16 to a long link bar'11. Each arm 61 has connected to it `the `links 14 and 11 and the link bars 11 extend on each side of the master cylinder A and are pivotally connected at 18 to each side of the yoke 25. Thus, when the master cylinder is operated by closing the valve 38 and the gear pump 31 operates to build up a hydraulic pressure under the pistons 2|, the piston rods 24 will force the yoke 25 outwardly away from the master cylinder A, thereby causing the link bars 11 to draw upon the links 14, lifting the arms 61 and elevating the links 69 so as to elevate the body.63 into dumping position as illustrated .in dotted outline in Figure 2. The operating cylinders Zllof the master cylinders provide a. powerful lifting force to the yoke 25 and the load in the body 63 is elevated so as to permit the same to be readilydumped from the body when it is desired.

My hoisting device operates directly against the approximate center of the body where the lifting force is most desired, and the lifting strain is distributed through the hoist supporting frame. The hoist supporting frame may be readily mounted on any motor truck chassis. The master hoisting cylinder being of a comparatively flat and compact nature, the same as a unit with the hoisting parts, fits neatly beneath the body to be hoisted. .This permits my hoist to be positioned where the frame of the truck is best adapted to receive the load and lifting strain, and by means of the supporting frame for the hoisting mechanism the lifting load is distributed over a greater area. on the frame of the chassis instead of being concentrated at a single point whichwould require wide saddles to prevent bending strain at a single point on the frame, as has been experienced heretofore. The master hoisting cylinder may be made as illustrated in Figure 6,` where the casing and the operating cylinder are concentric for larger apparatus and where only one working cylinder is desiredA with sufficient space beneath the dumping body to receive the larger'diameter of the master cylinder. The operation of the master cylinder Af illustrated in Figure 6 would be the same as that shown in the twin cylinder structure illustrated in Figure 4 and the pump 31 would operate in the same manner to build up the hydraulicpressure in this piston as in the master cylinder illustrated in Figure 4.

The master cylinder illustrated in Figure 4 with the twin working cylinders 20 is preferred for providing hoisting mechanism to operate truck bodies where minimum space is available or desired between the bottom of the body and the frame. With my hoisting structure the working cylinders are held stationary and the large reservoir about the same permits a good supply of hydraulic fluid, whiler the unitary construction of the parts without any outer pipe connections provides a hoisting mechanism which is adapted to give continued or uninterrupted service for a long period of time and without appreciable wear even though under heavy loads and hard use.

The pump connecting manifold with the other parts like the bearing block 36 and the pump body itself with the gears therein and the cover 43 are all easily assembled and therefore they may be readily replaced. 'I'he main wear comes on these parts under heavy strain and it is an easy matter to replace them, therefore I have provided a structure of ahoistingmechanism which I have found to be of a very desirable nature. I

In my hoisting mechanism, the master cylinder A is held in operative position by the angle member I3 andthe shaft I4 while the members I0 and II constitute a frame which supports the same between the side members I6 of the chassis of the motor truck. The fact that the hoisting cylinder A is of a compact nature, owing to the peculiar `construction of providing the working cylinders within the reservoir casing, permits the whole hoisting yunit to be assembled in a very compact form. The yoke 25 may be a drop forging of a simple nature as well as the arms 61, thereby providing very strong members for these working parts which carry the strain in the operation of the hoisting cylinder A, the piston rods 24 working directly against the yoke 25, while a pull is directed against the links 11 and 14, to pull the arm 61 upward around the shaft I4 in a manner to elevate or push upwardly on the link 69, thereby directing an upward force against the under cross holsters of the body 63 to elevate the same very readily. Any suitable driving means may be connected to operate the gear pump 31 and whenv the shaft 41 is operated by the transmission or other moving parts of the truck which carries the hoisting mechanism, a direct drive may be provided, and owing to the fact that the pump and connecting parts with the master cylinder A remain stationary at all times considerable wear is obviated over former types of hoisting mechanisms for dump bodies of motor trucks.

A feature resides in the direct connecting of the parts on the inner end of the master cylinder which permits a more direct passageway for the flow of the liquid in providing the hydraulic hoist and the free and ready escapement for the liquid such as oil out of the by-pass passageways 30 in the outwardmovement of the pistons 2 I, together with the large and closely connected reservoir for the surplus liquid or oil used in the operation of the hoist. These are features which distinguish my hoist from those used heretofore and I have found that my hoist has considerable advantage over these prior structures.

In accordance with the patent statutes, I have described the principles of operation of my hoist and I have endeavored to set forth the best embodiment thereof, however, the illustrations areonly suggestive of a means and apparatus for showing the principles and operation of my hoisting unit, and I desire to have it understood that the same may be adapted to other uses and the principles carried out by other variations within the scope of the following claims.

I claim:

1. A hoisting unit having a compact nature inl l o o 2,095,286" "fcluding, a pair` of workfcylindersfa casing`e`x` tendingraboutfsaid work cylinders adaptedto` Vprovidea reservoir thereabout, passageyvay'sydi o rectly connecting saidworkocylinders' with'r said reservoir, operating pistons and rods within said o `l`work cylinders,by-pass` valves carried by said" pistons to permit the relief of hydraulic pressure through said pistons at the limit of strokekinone` ,o direction, a manifold secured. to one fend ofisaid Leasing, a gear -pump directly connected tosaid o manifold on one end ofsaid casing of said work o,

ingoylindexs.` and reservoir,` passageways in said i manifold connecting said gear pump with said" reservoir and workingcylinders, and avalve for controlling the 1, operationof *saidj gear lpump `to operate said pistons withinsaid Working cylinders; o *f2.*A master'hoisting unit for hydraulic hoists including, a casing, spaced'parallel working 'cyl-e i indermeans within saifd casing; pistonsfwithin said cylinder means, parallelpiston -rods extend@` gear pump to `operate Asaid pistons `hydraulic pressure from said 'gear pump.`v

3. `A hoisting unit including. a comparatlyely,V Hat lmaster operating cylinder, working f cylinders forming apart of said master cylinder, a reservoir'in theremainingportion of `said cylinder,

pistons and rods loperable Within said workingV a cylinders, an operatingyoke connected to said said manifold at oneend of said xnastergcylinder, and valve means for lcontrolling the operation of the pistons within'said Work cylinders during' the operation of said gear pump by by-passing the .operating fluid through saidk manifold in said hydraulic master cylinder and gearpump past "saidpump andnfrom oneside of the pistons in,` Said workcylinders back tothe otherfside and o into thereservoir ofsaid master cylinder.` #3jV ing` from said pistons to a point `outsideof saidV g cylinder, arese'ryoir chamber; `formedby said cas#- ging betweensaid` casing andsaid work ,cylinder means, apump manifold connectedto,oneuend' of said master cylinder, `abearing-block adjacent f one l end i of said manifold; a gear pump block` having operating lgears vsecured-to `saidV bearing o bloclg `a 4coverfor tlieother side ol.` saidgear@ pump, passageways through said manifold and bearing` block connecting s aidzfgear pump with" o said Workcylinder` means andsaidfrsleryoir inH l said master cylindergand yalvegmeans; inV Said.` manifold block `to direct theoperationv of said,

4. VA master hoisting unitfor'h'ydraulic hoists l including, a casing, a plurality of parallel `spaced l p `working cylinders in said casing; pistons `within o :said cylindersparallel piston rodsextending from Y said pistons `to a pointoutside of saidcylinder, a "reservoir Within `said casing between said work cylinders, a manifold connected to one end of Saidrnaster cylinder, aahydraulic pump `in said manifold; passageways connecting said pump; and `saidvrorking cylinders, andvmeans to direct the foperation of said gear puxnpto operatesaid pis`` tons by hydraulic pressure from said gear pump.y

- HENRY J. RIACH `piston rods outside of one end of fsaid master cyl-k lnder, a manifold secured vat one `end of` said Vmaster cylinder, and a gear pump unit secured to" l

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