US2026938A

US2026938A - Lift

Info

Publication number: US2026938A
Application number: US672827A
Authority: US
Inventors: Charles W Eiserer
Original assignee: Rotary Lift Corp
Current assignee: Rotary Lift Corp
Priority date: 1933-05-25
Filing date: 1933-05-25
Publication date: 1936-01-07
Anticipated expiration: 1953-01-07

Description

Jan. 7, 1936.I c. w. EISERER LIFT 6 Sheets-Sheen`- l Filed May 25, 1935 www Jan. 7, 1936. c. W, EISERER 2,026,938

LIFT

Fied May 25, 1955 e sheets-sheet 2 j j I6 '0 ff' i .5

9 60 L77 J- 2 Q6 55 75 17 @den/Q21 zrZe-s/sefer Jah. 7, 1936. c. w. Exel-:RER `2,026,938

55 f kJ9 za* 27 19 66 6 1 l Yf JAF 6 1| @-5 T A32 30 23 .35 .El *i v V" 1 N r w 7- 17 'Jawat-2f.'

@fij

Jan. 7, i936.' `CQWHSERER 2,026,923@

LIFT

Fi\ledV Maly 25, 1933 6 SleetS-V-Shee 4 Z50 Y v VIIIIVI ml, w i. Cfzegjgagef Jan. 7, i936. C. Wl EISERER 2,026,938

LFT

Filed May 25, 1953 6 Sheets-Sheet 5 u l l 15A 22 l r L91 d u 30 225g M a ZOO 99 aadezazf fg )ma JM y, ,my S.

. Jan. 7, 1936. ci. w. ElsERl-:R 2,025,933

LIFT

Filed May 25, 1933 6 Sheets-Sheet 6 Patented Jeunk 7*,"1936 4 j v v i A "UNIT-Ensures.: PATENT-orner f y g 2,626,938 r 7 Charles W. Eiserer, Chicago, `lli., assigner 'Rotary Lift Company, Memphis, Tenn., a corporationjofTennessee` t Application-May 25.51933, sedano. 612.321 Y somma (omni---lrlrfV v Y invention relates to lifts, particularly vauto-V Referring first to` Fig'. 1, the lmultiple lift` in-` mobile servicing lifts of the tluidoperated type 4stallation-chosenilory illustration comprises four such as are employed in iilling stations and ga-w liIts,A,`B, C and D, all of which arearranged to ragesbodily to elevate anautomobil'e torender lreceive pressure-fluid forelevation from a com- '.5 the'chassisand underbody readily accessible'for mon, source of power supply. 'Each lift may be'of 5 inspection, cleaning and repair. any'approved type such,l for example, as thatset Oneoi the objects of rny'invention is to provide forth in `Peter J, Lunati Patent 1,552,326'granted animproved arrangement for the selective oper-v September 1, 1925.4 Each liftor station is pro-` ationzofaplurality of lifts from a single -source of videdwith van individual control A', B', C' and D" l mud pressure, f 1 1 respectively by meansorwhichx the application `1o Another object is to provide aplurality of lifts and release of pressure is` 'independently ,coriwitn/individual-controi for a common. source of trollednnd the common source ofpower can be operatingzpower.; n z' l started to create thepressure required.4 `Another object is to provide a plurality of `liits L The common source .of power or power plant 15. and a common source of operatinglpower withV includesa pressure-tluidreservoir lli-the prelI controls which are individual to a lift and in com-- ferred uid being oil---yaL pump I I for withdrawing lmon with 'the power source. i viluidl f roxnthey rasercolin-and,k raming Vil-m the `Another obiectisto provideeach of a' plurality lifts, a pump dri g'l-lnotor yl2 and, a motor of lifts withacontrol station'which individually starter I3. v u

2- gverns the application of 'pressure -to the asso-vv 1The reservoir. may be ofany suitable construe- 20 ciatedliftand initiates the operation of a prese tion. preferably. `with a capacity great* enough sure producing plant which is common to all of to supply liquid to permit, if desired, simultathe lifts. v neous elevation of all oi the lifts associated f Another object is to'provide a controlvalve and therewith. The pressure iiuid pump may be of 25 gwitehparticularlly .adapted for each lift cfa mule any appropriate type having a liquid and pres- 2 5 tiplelift installation. v sure capacity great enough to meet the condi-A other emette-fend advantages wm hereinafter tiens existent at the particular installation. a ,ppe'ar)` f e, rotary type of pump directly connected toits in the tiraurlings;l f driving motor is4 shown. It has an inlet il con- 39 Fig.f1 shows, in a partially diagrammatic mannected to reservoir Ilijand an outlet connected 30' ner, an installation of four lifts, all deriving power to a pressure 'supply pipeV l5. The motor may from asingle'source and arranged for individual be of any desired type, preferably electrically controly' f f operated,- andof the size, voltage-and electrical Fig. 211s an enlarged side elevation of one form characteristics required. The motor starter likeof individual combined control valveand switch; wise Amay be of anyv appropriate type, preferably 3 5 Fig. 3 is a front elevationand partial section o f it is of the automatic type, several varieties of this ,clbmedwalve' and switch with the upper which vare in common use and well known, wherepart of the control handle broken away: by, when a lcontrol circuit vthereto isV closed ,or

, Flggd is a -vertlcal section on the line of opened, uthe power circuit to the motor is vclosed Fig. 2; v or ,opened and current limiting resistance or 49 FigQ isa section on the line 5-5 of Fig. 4; other` regulatory and protective equipment is cui; Flg`.`6is asection on the line B-B of Fig. 5; 011i 0r cui? inprpelly t0 start and stop the motor Fig. 7 is an enlarged end elevation and partial and prevent excessive current nowlng thereto. sectionof a modified formf-probably the prefer- In general the control equipment yor control n. l we and switch; station at each lift comprises a combined valve abogs-:iggllugev' 01ml .n -and master switch, a .preferred embodiment of l Y -whichwillbehereinafter explained. operable by Fig-9is adem vtiixwogln'f the stop arrange a manually actuated control handle i6. Each ment fol-.the opera g an e. l f `controlv handle is movable to three positions,-

FIS-101s a-Vertical'secon' y g l `a neutral or mid-position in which the circuit 50' 1 Fig. 1l is a section on theline lI-II ofFlg.10; to the motor Starter is4 open and communication 212.12m a diagrammatic illustra-tion 0f *modbetween the .pump and the associated lift is iiied type of multiple lift installation; and e closed. an"up'. or, as `viewedin Figs. 1, 3 and 4, Fig. 13 is anenlarsed Swtion On the'llne ll-l an extreme `right hand position, in which the circuit to the motor starter is closed and communi- 55 of Fig. 12. y

cation between the pump and associated lift is open with the result that the lift is elevated, and a down" or, as viewed in Figs. 1, 3 and 4, an extreme left hand position, in which the circuit to the motor starter remains open and communication is established through a return pipe I1 between the associated lift vand the pressure fluid reservoir, with the result that theweight of the lift plunger and its load can force the pressure fluid back into the reservoir and the lift can descend.

Referring now to Figs. 2 to 6, the construction and operation of one form of individual lift control will be explained. The controls atrall lifts may be alike. Y

The control comprises a multiple valve and an electric switch which are selectively operated by the actuation of the control handle tothe three positions heretofore mentioned. It includes a casing I9 which has an inlet 26 connected to supply pipe I6, an outlet 2| connected by a pipe 22 to the associated lift and a return 23 connected to return pipe I1. Inlet 2|! leads into an inlet chamber 24, the outlet of which is a port 26 controlled by a pressure-application or "up valve 26. Port 25 connects inlet chamber 24 with an intermediate chamber 21,jthe -outlet of which is a check-port 29 controlled by an automatic check valve 29.'

The stem 30 of check valve 29 is slidably seated in a socket formed in a boss 3| oi a threaded plug 32 which nts and tightly closes a threaded opening throughone outside wall of`casing I9. The check valvecan be placed within the casing and, should occasion require, removed therefrom through the opening which is closed by-plug l32.

A helical spring 33 normally biases check valve 29 to closed position, interrupting' communication between intermediate chamber 21 and a combined inlet-outlet chamber 34. Chamber 34 includes the outlet 2|' and has a return port 35 which connects it to a return chamber 36. Return chamber 36 communicates with the return pipe I1 through return connection 23. A pressure release or "down valve 31 controls port 35 and consequently the communication between chambers 34 and 36. Y

Normally valves 24 andy 31 stand closed, but each may be operated by the manipulation of the control handle independently of the other. Up valve 2 6 has a stem which has a sliding nt in a bearing 4I provided by the valve casing and projects through and beyond the casing so as to be operable from the outside. A packing gland 42, which screws upon a threaded boss 43 projecting from the casing and surrounding valve stem 40, serves to compress a packing 44 about the valve stem to prevent leakage. A` biasing spring 46 surrounds valve stem 40 and is retained between gland 42 and a stop washer 46. Washer 46 is heldin place upon the valve stem by a 'cotter pin 41 which passes through the stem. Consequently spring 4I) urges the up" valve 26 to closed position.

A bracket 46, extending upwardly from the valve casing, has the control handle I6 pivotally attached thereto by a pin 49 and the handle has a cam 66 formed integrally therewith or rigidly attached thereto in a position to act upon valve stem 43. 'I'hus when the control handle is moved to up" position (i. e., toward the right as viewed in Figs. 1, 3 and 4) cam 69 forces stern 40 inwardly to unseat valve 26 and open the port between chambers 24 and 21. Pressure-fluid supplied by the pump can then ilow through inlet 20 and chamber 24 into chamber 21 where it acts upon check valve 29 to open the same. 'I'he fluid thereupon flows on into chamber 34 and out through outlet 2I and pipe 22 to the lift, causing the plunger of the lift to rise. The check valve g automatically prevents the ow of pressure-fluid in the reverse direction.

Release valve 31 has a stem 66 which is likewise slidably mounted in the casing with a ilt made fluid tight by a packing 66 and a gland 10 51. It has a biasing spring 59 arranged to urge the release valve to closed position. A cam 69 which is pivotally attached to bracket 43 by a pin 60 has one end in position to engage the upper end of stem 65 and its other end 6| in posi- 1g tion to be engaged by a cam surface 62 of cam 60. Thus when the control handle is moved to down position (i. e., toward the left as viewed in Figs. 1, 3 and 4) cam 69 is rotated counterclockwise, its cam surface 62 rotates cam 69 in 20 ay counterclockwise direction and stem 6I is forced inwardly, against the force of spring 63, to open release valve 31 and establish communi-v cation between chambers 34 and 36. Under this condition up valve 26 is closed and, because gg pressure from the pump `.is thereby interrupted, check valve 29 is also closed and the pressure iluld can ilow back from the lift through pipe 22 and chamber 34 through port 35 into chamber 36 and from thence through outlet, 23 and 30 pipe I1 back to the reservoir. The weight of the lift plunger and its load forces the fluid back through this path to the reservoir andthe lift can descend. v y' Y In the mid-position of control handle I6 all 35 three of ,the valves-26,129 and 31are closed and whatever pressure uid has been appliedto the lift is retained in status quo. As a result the lift remains in whateverposition it had attained when the control handle was moved to mid or o neutral position. A spring 63 held by a stud 64 which projects from .one of the brackets 46 and which bears at one end against the bracket and at the other end against control handle I6 assists in returning the control handle to' mid position 45 whenever it is released by the operator.

A motor starter control switch. is mounted in an auxiliary switch housing 66 whichis attached to the valve casing bysuitable means, such as screws 61; y Switch 66, which may be of 50 any of the well known appropriate types is provided with a push button 68. When the push button is depressed the switch is closed andA when the push button is released the switch automatically opens. Cam 59 has an arm 69 which can 55' engage a lever 19 when'the cam is moved in a clockwise direction; i. e., when the control handle is moved to up" position.

Lever 10 is attachedto a shaft 1I which is journaled in switch housing 66 and carries at its 60 inner end within the housing a switch operating lever 12. Lever 12 may be adjustably fixed to shaft 1I by a set screw 13. When the control handle is moved to "up position to open valve 26 and establish communication between the 65 common power plant and theassociated lift, cam arm 69, engages lever 10 and rocks the same and shaft 1I and switch operating lever 12 to depress the push button 63 and effect the closure of the switch. All of the switches of all of the lift con- 70 trol stations are connected in parallel to motor starter I3 so that upon the closure of any switch the motor starter is brought into action .to start the motor. Likewise the opening of any switch tends to act upon the motor starter to open the :5

circuit to the lmotor but; since all of thecontrol switches areln parallel, the motor starter will tiple lifty installation is as follows :4 To start the elevation of any of theslifts A; Bl C kand D, the Vcontrol handle fof the control station'adjacent that lift is moved to its fup" position. This operation of the control handle starts themOtor of the power station and also' opens control'valve 26.

the lift hasv been elevated te thel desiredY height the control handle is moved to mid-position whereupon the circuit to the motor is interrupted and valve 2Gjis closed.y Due to th automatic eiosure erthe cheek veive 2.9 the 1in wiii remain inv its elevated position until the control-handle oi. its control station'is movedto the down po 'sition. When the handle is moved to the "down" position releasevalve 31 isopened permitting the weight oi the `lift and its load to torce the pressure-fluid back to 'the reservoir allowing the liftftomdescejnd. e A y l Whenever the' source of power is started from any lift or controlstation it continues to `operate Y untilthe requirement for power by `all'of the liftsis satisfied'. Thus', the actuation to elevating or '"up position `of the control Vassociatedwith any particular lift starts the common powerl plant to supply the pressure-fluid required for elevation and also establishes communication between the liftfand the power plant so that the pressureffluid can act upon the lift to elevate the seme. -When the' uit has been eieva'tedte the` desired extent the control associated therewith is restored to normal or neutral position whereupon the communicationbetween .the lift and power plant is` closed, lstopping7 the ilow of-pressureiluld therebetween, vand at the j same `time stopf ping 'the lcommon power plant unless the eleva- A tionoi such otherlift associated therewith has `isis lift being permitted tocome down;

is stlll'required.

been started and, in consequence, pressure-fluid yShouldv such a conditionobtain thepower plant remains in operationr until' the controls of all v lifts associated therewith Vare restored toneutral Of normal `inoperative v.mid-position. Each Vlift maybe lowered from elevated position-independentlyl or, all others by manipulating the control handle 4to the down 'positionwherupon the pressure-fluidis permitted'to return fromfthe lift to the common power plant resulting inthe Figsf'l to 11 showv afslightly modiiled control,

which, because of the-smaller'number of 'parts and more vcomplete housing Vvof the operating mechanism, has someuadvantages over the `one just'described. Y

` This combined valve and motor controlswitchV includes'avalvecasing 15 to which are attached a switch housing 16 andan operating-camL-hous- 11. Valve casing 15 has an inlet 18 for connectionto supply pipe'l5, an outlet-19 for connection by `'means of pipe 22 tothe associated lift and a return 80 for connection to return pipe |1. Inlet 18`leads-into an inlet chamber `85 which has* an'outlet through port 86 controlled by-a pressure application or up"valve 81. *Port 80 connects inlet chamber as' with en intermediate chamber88, theoutlet oi which is a check port "'09 controlled by an automaticcheck valve' 90.

This check valve is provided with two guide stems 9| and 92 projecting from `opposite faces thereof. Stem `9| has a sliding llt inta socket provided by a boss' 93 formed in one wall offvalve casing 15.

The other stem 92 slidably ts in a-socket formed in aiboss 94 of a screw plug95 which l c threads tightly into an opening in the wall of casing 15 in alignment with port 89. A 'spring 96 normally biases check valve 90 to closed position, interrupting communication between inter-v mediate chamber 88 anda-combined inlet-outlet lo chamber 91; Chamber 91 includes the outlet 19 and has a return port 98 which connects it to a return chamber 99. Return chambers communicates with return pipe |1 through return connection 80. A pressure release or down valve l0 |00 "controls port 98. f Normally valves 81 and |00 stand closed, but each may be operatedindependently of the other by Ithe mai'ilpulation.` of the control'handle |6f. Up valve 81 has a stem |05 -fixed thereto or 20 made integral therewith which has a sliding ilt in a 'bearing plug |06. -This plug is kexternally, threaded to fit an vinternally threaded boss |01 which 4forms a rini about an opening in one .wall of casing 15. The bore through plug |06'is en- 25 vlarged at its buter end toform a chamber for slidably retained ina bearing providedv by a plug 85..

lllfand is biased toanormally closed position by a spring-H5. 'i

A `The outer ends of `valve stems |05 andl |3project into cam 'housing`1'|. This cam' housing is formed by asomewhat oval shaped flange |20, 40 which projectsupwardly above the topl wall ol valve casing V15, and a correspondinglyfshaped Idome like coverv |2| whichflts over flange |20. The' valve casing is provided with lugs '|22 having threaded openings therethroughv and cover 4:5v 2| has similar lugs |23 which have unthreaded openings vregistering with the threaded openings in lugs |22. VHeaded screws |24I which Apass throughthe'unthreaded openings of covery lugs |28 and into thethread'ed openingsofvalve cas- 50 inglugs |22 securelyattach the cover of: the cam housingin place'.` The cover |2| has a bearing boss |25 formed therein atvone end and oiset jfrom the lplane common tothe axes 'o1' stems |05 and |3. The opposite endof cover |2| has an 55 Y [opening |26 therethrough in axial alignment withsquaredto fit a correspondingsquare opening in the hub of handle I0',V and its tipthreaded for a nut |30, which serves toretainthe handle in place thereon.l

' y Shaft |28 is provided with two oppositely di- Wrected curve faced cams |35 and |30 which are 70 located to actV upon valve stems |05 and |3respectively. 'I'hus whencontrol handle I0' is `moved to up position (l. e., counterclockwise as viewed in Fig. '1) cam I35depresses stem |05 to open the "upfvalve 81 and'when it is movedto 75 the opposite or down podtion cam |88 depresses stem ||8 to open "down" valve |08. When returned -to mid or neutral position from either its up" or down position, the corresponding cam |88or |86 releases its depressed valve stem and the up or down" valve is closed by its biasins spring.

Thewallotcoveri maybeextendedinasegment shaped stop |81 (see particularly Fig. 9) againstthe ends o! which a pin .|88 projecting from sleeve |21 will strike at vthe full up and down positions of control handle i8'. Set screw |29 and pin |88, which also may be a set screw, serve to .retain the cam shaft in proper pnsition. The diagonal position o! the cam shaft relative to the axial plane of the two valve stems-a condition most clearly shown in Pig.

-insures that the two oppositely directed camsv |38 and |86 can act upon the valve stems with substantially axial thrust. f I

Shaft |28, also carriesy a -cam |40 which is formed thereon in a position to engage the pushrod |4| and thereby actuate a motor control switch-|42. Switch |42, which may be oi any approved push-button type, is mounted in a switch housing |48. This switch housing is `in the iorm of a box, preferably cast in one'piece except i'or the iront which is closed by a suitable gasket and a screw attached cover plate |44.v The rear wall of the switch box is formed with four lugs or posts |48, upon which the switch is mounted by means oi screws |46, and a rearwardly projecting cylindrical boss 41. Boss |41 projects through a hole in cam housing cover |20 and has a bore therethrough for slidably holding push rod |4|.` The inner end oi push rod |4| is in aposition to engage and operate the push button |48 of switch |42, the button beingnormally held in its outer or switch-open position by a spring |49. When control handle I6' is moved to up posi? tion it not only efiects' the openingoi up valve 81as heretofore described, but also it causes cam |40 tov force push-rod |4| outwardly against push button |48 and thereby close the contacts of switch |42 to ystart the motor. ,The return of the control handle to mid or neutral position perl mits the switch to open to stop the motorA and also, as previously described, permits the up` valve to close. The switch box |43 is attached to the side of the valve casing by screws |80.

Brieiiy reviewed, the operation oi this control is as follows: Movement of` control handle I6' from mid to up position closes switchk |42to start the motor and opens "up" valve 81 toA open communication between the fiuidpressure pump andthe associated liit. Pressure fluid flows from the pump through supply pipe I8 to inlet chamber 88 and from thence through port'86, which is now open, into intermediate chamber V88. 'I'he pressure against checkl valve 90 opens the same so that thepressure fluid ilows through port 89 'into outlet chamber 91 and from thence through pipe 22 tothe associated lift, causing the same to rise. Whenever control handle I6 is returned to mid-position switch |42 is opened and valve 81V is closed, stopping. the motor (unless some other litt is requiring power) and shutting oi! the supply oi! pressure fluid. Check valve 90 then prevents the return of pressure fluid by way of the supply pipe and consequently thelitt remains in its elevated position. When it is desired to lower -the liit handle I6' is moved to down"` position whereupon release valve is opened, permitting the pressure uid toviiow back from the liit through

chambers

91 and 98 and return pipe i1.

annesse The circuit connections between the switches of the several control stations and the motor starter is such that whenever the control handle o! any control is returned from up to mid-position the motor of the power supply unit does not stop ii s the'control handle of any other station is then in up" position. In` other words, just as in the case ci the previously described installation, any control station can start the motor but, when once started, the motor does not stop ii any liit requires power, although the supply oipressure tiuid may be interrupted at any time at any litt.

With either of the controls heretofore described the control handle automatically returns to mid vor neutral'position whenreleased while out of l5 that position.

Fig. 12 shows a typical arrangement for controlling a plurality o! liits from a single control station. Three lifts 1", G and H are shown, the same being individually controlled i'roma single 20 control station I and receiving pressure-fluid from a common power plant J. Preferably the control station and power plant are locatedr close enough together to enable an operator to manipulate both at the same time. The power piant'per se forms 25 no part oi the present invention but, although any appropriate construction may be employed, I prefer to use the type set' forth in my copending application Serial No. 672,826,`filed May 25, 1933. In general the power plant should include a pressure-duid reservoir, a motor drivenpump for withdrawing fluid from. the reservoir and iorcing the same through a common supply pipe |88 to control station I and suitable means for controlling the starting and stopping oi the pump motor.

The control station comprises a multiple port valve ISB-the details oi which are shown most clearly in'-Flig. 13, which by means of a control handle |81 may be operated selectively to con- 40 nect any one of the three liits to supply pipe |88. This control valve has tour external connections |59, |89, and |6| leading through ports |62, |68, |64 and |68 respectively to a central cylindrica l distributing chamber |66. ConnectionA |88 is 45 connected to supply pipe |88 while connections |59|68'a nd |6| are connected by pipes |61', |68 and |69 respectively to lifts F, G and H. A distributing head |10 is rotatably iitted in chamber |66 and is provided with a central passage |1| 50 A relatively large port |12 and three smaller ports, |18,- |14 and |18 aiiord communication between central passage |1| vand the exterior of valve |10. These ports enable the distributingl valve-head to interconnect port |62 with anyone 55l of. the ports |68, |64 or |68 Adepending upon the position to which control handle |81 is moved.

in the mid-position as shown in Fig. 13 port |62 communicates through port |12, chamber |1| and port |14 to port |64 and trom thence C0 through pipe |68 to lift G. In this condition the supply pipe |88 and consequently the source of iiuid pressure is connected to lift G. When the pump is in operation pressure iluid is supplied to iiit G to elevatev the same; 'when the pump is 05 stopped the lweight of the lift plunger and itsr load can force the pressure fluid back into the reservoir, permitting the lift to descend. In the other positions of the control handle the power plant may be similarly connected to either liit F or liftH, as desired,

Oi course, it will be understood that, with the same or a slightly modiiied type of control valve, the number oi liits controllable from the single central control station may be decreased and ,7v

that, by providingmore ports in the distributing head thereof a greater number of lifts can be lontrolled. f

Having thus illustrated and described the nature and typical embodiments lof my invention,

what I claim and desire to secure by United States Letters Patentl is as follows:

1. 'In combination, a plurality of fiuidoperated lifts, a source of fluid pressure common to all of the lifts,` and an independent controlr for each lift, each control including valves and a switch, the switches being adapted and arranged to start the operation of the common source of fluid pressure and the valves to establish and interrupt the flow of pressure fluid between the source of pressure and the associated lift and in cooperation with all of the switches of all other controls to stop the operation of the common source of fluid pressure.

2. In combination, a plurality of uid operated lifts, a fluid pressure pump common to all of the lifts, a motor for operating the pump, fluid connections between the pump and all of the lifts, and a control associated with each lift, each control including valves in the uid connections and a switchcontrolling the motor-and being adapted and arranged to start the'motor and open `and close the fluid connection between the pump and its associated lift and in cooperation with all of the switches of all other controls to stop the motor.v

3. In combination a plurality of iiuid operated lifts, a fluid pressure pump lcommon to all of the lifts, a motor for driving the pump, fluid supply connections between the pump and allv of the lifts,fiuid return connections between the pump and all of the lifts, and a control individual to each lift, each control including a switch and being capable of opening and closing communication between its lift and the fluid supply and return connections and of starting the motor and in cooperation with all of the switches of other controls of stopping the motor.

4. In a lift installation comprising a, plurality of uid operated lifts and a common motor operated fluid pressure pump, the combination of an independent control for each lifteach control comprising a valve for establishing and interrupting communication between its lift and the pump, a switch for starting the motor, and a control handle which simultaneously actuates the valve and switch. A

5. A multiple lift installation Acomprising a plurality of -hydraulic lifts; la fluid pressure pump common to all of the lifts; a motor for driving the pump: and an independent control station associated vwith each lift. each con-trol station including a combined pressure-application, check and pressure-release valves, a switch for controlling the operation of the motor, and a single handle for controlling the pressure-application and pressure-release valves and the switch.

6. In a multiple lift installation the combination with a plurality of hydraulic lifts, and a common source of fluid pressure including a pump and motor for driving the same of a plurality of independent lift controls, one for each lift and each comprising a pressure-application control valve, a check valve and a pressure-release valve mounted in a common valve casing, a motor control switch mounted on the valve casing, a manually actuated control handle mounted on the valve casing, and operative connections between the control handle and the pressure-application and pressure-release valves and the motor control switch. i v

7. The ycombination with a control unit comprising a'valve casing having an inlet port, acombined inlet and outlet port, and an outletport; fa 5 valve. controlling the inlet port; avalve controlling the outlet port, each of said valves having" an actuating stem slidably mounted in and projecting through the casing; `a manually actuated control handle pivotally mounted on the casing and 10 operable to two extreme positions and a mid-position; operative connections between the control handle and both of the valve stems whereby the handle opens the inlet valve when moved to one extreme position, opens the outlet valve when l5 moved to the other extreme position and effects closure of both valves when in mid-position; an

automatic check valve between the inlet port and the combined inlet and outlet port to permit fluid to flow from the inlet port to the combined inlet 20 and outlet port and prevent now of uid in the reverse direction; and a switch operable by the vhandle when moved to the position opening the inlet valve of a pressure fluid actuated lift havingv fluid connections with the outlet and comport; a valve controlling the inlet port; a valve controlling the outlet port, each valve having an actuating stem slidably mounted in and projecting through the casing; a manually actuatedy control handle pivotally mounted on the casing; a shaft operable by the handle; a switch mounted on the casing; and three cams operable by the 40 shaft, two of said cams being operable upon the valve stems and one being operable upon the switch, the two cams operable upon the valve stems being oppositely 'related to the shaft so that movement of the handle in opposite directions from -a mid-position operates one or the other of said valves and the cam operable upon the switch being sorelated to the other two cams that the switch is open when the handle is in mid-position and is closed when the handle is moved to open the inlet valve of a pressure fluid actuated lift having fluid connections with the outlet and combined ports of the control unit; a uid pump connected to the inlet port of the control unit; a pump motor; and circuit connections whereby the circuit to the motor is opened and Y closed when the switch opens and-closes.

casing; three cams operable by the shaft, two of said cams being operable upon the valve stems and one being operable upon the switch, the two cams operable upon the valve stems being oppositely related to the shaft so that movement of the handle in opposite directions from a mid-position operates one or the other of said valves and the cam operable upon the switch being so related to the other two cams that the switch is 'Mw tion and Il fluid whuted'lltt :im mid-pod is mand w open the theoutletgndeomblned ccheckvdveloteda fluid pxnmpreonne und outlet control unit: a.