US2235246A

US2235246A - Hoist

Info

Publication number: US2235246A
Application number: US331403A
Authority: US
Inventors: William C Anthony
Original assignee: Anthony Co
Current assignee: Anthony Co
Priority date: 1940-04-24
Filing date: 1940-04-24
Publication date: 1941-03-18
Anticipated expiration: 1958-03-18

Description

HOIST Filed April 24, 1940 4.. Sheets-Sheet 'l r o 0 l., wu J n J r n uw wi. f um n0 f W W L- W. m W Nk--- w70 WN N u mm. W 70j uw. WW MN MW b L --r\------, w Nw \m| a: ww g l u mm bx C wm n \|A|/, QW ,NINN w wm. N NQ March 18, 1941 w. c. ANTHONY HQIST Filed' April 24, 1840 4 Sheets-She'et 2 March 1s, 1941. w C. ANTHONY 2235,24@

Hors'r Filed April 24, 1940 4 sheetsfsnet sy p l L -Nu i l .3. 1 1 1 1 i 5 f a I 1 2--+ ZZA l l 25-T 1 1 l 1 i 71 1 1 I 1 l 1 ;1' i 1 1 1 l 74 I l l l 1 F 73 Lui l i II WIA-- 8 9 32 6 3; 9' 8 .1 MQW/71 f f' @29 3 4 BDA i?, d w 1 @1143 l /fx /l 28 24 2'5 2Q 27 9 54 5J, F59. 5. fri/ 7- f 57| 55 March 18, 1941. w. c. ANTHONY HOIST Filed April 24, 1940 4 Sheets-sheet 4 Patented Mar. 18, 1941 HOIST William c. Anthony, sweater, nl., assigner to Anthony Company, Streator, Ill., a corporation of Illinois Application April 24, 1940, Serial No. 331,403

20 Claims.

This invention relates to a hoisting apparatus and in the particular form here shown is embodied in a hoist of the type gener-ally suitable for hoisting or raising automotive vehicles and '5f similar apparatus so that it may be repaired, inspected and otherwise Worked upon. The mechanism here shown comprises a plurality of hydraulic elevating or raising means and includes automatic means for synchronizing the several hydraulic raising means to make sure that they rise equally s-o that whatever is being raised-an automobile or the like-is constantly and automatically held level. An object of the invention is, therefore, to synchronize a plurality of hoisting means so that whatever is being raised is constantly held level. Another object is to synchronize a plurality of hydraulic hoisting means to effect level raising. Another object is to provide an automatic electrical control for synchronizing and maintaining level a plurality of hoisting means whether they be hydraulic or not.

Other objects will appear from time to time throughout the specification and the claims.

The invention is illustrated more or less diagramm'atically in the accompanying drawings, wherein:

' Figure 1 is a plan view with parts broken away and parts lin section, showing a hydraulic hoist assembly suitable for -raising automobiles;

Figure 2 is a side elevation of the structure shown in Figure 1 with parts omitted in raised position;

Figure 3 -is an end view on an enlarged scale of the device shown in Figures 1 and 2, with parts omitted, in lowered position;

`Figure 4 is a vertical sectional detail with parts in elevation, taken on an enlarged scale 'at line 4 4 of Figure 1;

Figure 5 is a longitudinal sectional detail on an enlarged scale, showing the hydraulic valve of Figure l;

Figure 6 is a schematic wiring diagram showing the electrical connections for the control of the mechanism shown in the other figures;

Figure '7 is a schematic detail illustrating the electrical control for the valves and other parts shown -in Figure 3.

Like parts are designated by like characters throughout the specification and the drawings.

The mechanism of the present invention may be mounted on any support; It need not be xed to that support. It may, however, be secured to a prepared base such asa floor. As shown, a iioor or foundation or supporting surface I carries the mechanism andV upon it are four iixed pistons 2a,

2b, 2c and 2d. Each of the pistons is preferably attached to a base plate 3 which actually contacts the supporting surface upon which the apparatus rests. At their upper ends the pistons 2 may carry piston members 4 which are provided, if 5 desired, with suitable contacting or packing surface members.

Positioned about each of the

pistons

2, 4 is a cylinder 5. Since the assembly as shown is intended primarily for raising an automobile, the 10 pistons and cylinders are arranged in a rectangle which is longer than it is Wide. The two cylinders at each end are, therefore, preferably joined by cradle members 6 which may be depressed or notched as at l, 'I to permit passage of the wheels l5 of the vehicle, and the cradle members 6 may be additionally fastened to the cylinders by

Webs

8, 8, and they are joined together by

longitudinal frame members

9, 9, In the form here shown, these frame members are I beams. These beams 20 serve to tie the mechanism together and, under many conditions, to support the load which is to be raised, and they servev also to support the controlling and hoisting mechanism.

Upon one of the cyl-inders 5, there is mounted 25 a supporting platform or frame Il). This frame carries a large part of the mechanism including the pump, the sump and many of the control devices so tha-t the entire hydraulic drive and its control rises and falls when the apparatus is 30 in use. Upon the frame is mounted a sump II and upon the sump is mounted `a housing I2 within which the electr-ical control devices are housed.

A handle I3V extends outwardly for operation of this control device or switch assembly and means '35 are provided for 'an electrical connection I4 which may be plugged into a plug I5 to connect the system with a source of current. Beneath the frame I0 is mounted the driving motor I I5.l This motor is connected to a pump I'I by a con- 40 nection I8 so that the pump is driven by the motor when energized.

Each of the cylinders 5 is connected by suitable piping Withthe pump so that each is sup-plied with pressure fluid. Thus, a pipe I9 runs from 45 the pump Il. A check Valve 20 may be positioned in the line and a pressure relief valve 2| may also be positioned in the line. The pipe I9 is` continued beyond the pressure relief valve 2l. It

may be provided with a shield 22 which is posi- 50 tioned over it and prevents its being broken when the wheel of a vehicle passes over it. The lower edges of the shield 22, as shown in Figure 2', are on the same level as the bottom of the members 9. Like them, the shield rests upon the ground or 55 iioor, when the hoist is in the lowered position. The pipe I9 may be carried through or under the member 1 and one of the members 9. In that case no shield would be necessary. The pipe I9 is connected to a pipe 23 supported upon one of the frame members 9. This pipe extends to both ends of the frame assembly. At the righthand end oi the frame, as shown in Figures 1 and 2, it extends partly across the cradle member 6 and there communicates with a pipe 24 which at one end as at 25 connects with one cylinder 5 and at the other end as at 25 connects with the other cylinder 5.

Solenoid valves

21, 28 are inserted, respectively, in the pipe sections 2'5, 26, and are operated to control the passage of fluid to and from their respective cylinders. They are provided, respectively, with

solenoids

29 and 39 which are operated in a manner which will be described below. The righthand cradle member 6 shown in Figures 1, 2' and 3 is provided also with a pair of mercury switches 3| and 32. Adjacent its righthand end, as shown in Figures 1 and 2, the pipe 23 is provided with a solenoid valve 33 which is operated by a solenoid 34.

At the lefthand end, as shown in Figures 1 and 2, the arrangement of pipes, valves and solenoid is substantially the same as that described above for the righthand end. There is, thus, a pipe 35 which is joined to the pipe 23 and which, by means of

sections

36 and 31, communicates pressure fluid to the two

cylinders

5, 5 at that, end of the apparatus. Each of the

sections

36 and 31 is, respectively, controlled by

solenoid valves

38, 39, which are, respectively, operated by solenoids 49, 4I. There is also a solenoid valve 42 adjacent the lefthand end of the pipe 23 which is operated by a solenoid 43. There is also positioned on the lefthand cradle 6 of Figures 1 and 2 a pair of

mercury switches

44 and 45.

Positioned upon one of the I beams 9 is a pair of

mercury switches

45 and 41. In each case the respective pairs of mercury switches mentioned are positioned adjacent the center line of the member which supports them; one being positioned slightly to the left of the center line and the other being positioned slightly to the right of that line.

The pressure fluid flows from the sump I I to the pump I1 through a pipe or passage 48 and fluid may be returned to the sump by a pipe 4or passage 49 which is connected to the pressure relief or pop-oi valve 2| so that fluid escaping through this pop-01T valve when the latter is operated will be returned to the sump through the pipe 49.

A

bleeder pipe

59, 5| is provided in the system and is connected at one end to the pipe I9, preferably beyond the check valve and the pop-oil valve. The pipe 5| is connected at one end to the sump. A solenoid valve 52 is inserted in the bleeder pipe 59, 5I and is provided with a solenoid 53 to operate it.

The hydraulic valve shown in Figure 5 is typical of the solenoid valves shown throughout the drawings and a description of the showing of Figure 5 will suflicefor all of them. For the purposes of the description, it will be assumed that the valve of Figure 5 is the valve 52', operated by the solenoid 53 although, preferably, all of the other solenoid operated hydraulic valves are the same. This includes the

valves

21, 28, 33, 38, 39 and 42. The solenoid valve is arranged automatically to be and to remain closed except upon actuation of the solenoid. The inlet passage 54 is connected to the pipe 59. The outlet passage 55 is connected to the pipe 5|, and a passage 56 is arranged to join them. A valve member comprising two relatively thickened

sections

51 and 58 and two

thinner sections

59 and 69 is arranged to reciprocate in suitable guides and in the passage 59; thus, it opens and closes that passage, depending upon its position. At its outer end the sliding valve member is provided with a spring 8| which bears at one end against any suitable portion of the housing 52 and at the other against a plate 62 adjustably held in position by a nut 63. At its opposite end the valve is connected to a link or other suitable member 64 which is arranged within the solenoid 53.

Packings 65 are `arranged at each end of the valve and engage the

sections

51 and 58 to prevent leakage past them from the housing.

Ducts

66 and 61 are provided, respectively, about the

valve sections

51 and 58, and liquid which leaks past these sections is received in the ducts and then flows through

passages

68 and 69 to a passage 19 from which a tube 1I returns the leakage to the sump I I. In the case of the solenoid valves mounted on the framework, they are connected to a return pipe system indicated generally by the numeral 12, `and this return pipe system returns the pressure fluid which may leak from any of the solenoid valves to the sump I, entering that sump as at 13.

While the electrical mechanism may be connected in a variety of ways, that shown in Figures 6 and '7 is one suitable wiring and control arrangement. In general, the control in the raising operation to accomplish and maintain leveling is the opposite for the lowering control and, hence, two circuits are shown. That shown in Figures Gand 'l in full lines is the raising control circuit; and that shown in Figures 6 and 7 in dotted lines is the lowering control circuit. The dotted line showing is adopted because it is believed that the showing can be made clearer in that manner than by showing both circuits in full lines.

The member I3 is the controlling lever. The lever as shown in Figure 6 is in the off or nonoperating position. If moved to the left from the position of Figure 7 toward the point marked X, it is brought into the raising position. If

moved to the right toward the position Y, it isv brought into the lowering position.

14, are power lines through which electrical current enters from any suitable source to the panel 16 upon which the lever or handle I3 is mounted. These power lines in the particular form here shown would normally be contained in the cable I4 which i-s plugged into any suitable socket I5.

The raising circuit will now be described. When the lever I3 is moved to the position X, its contact portion 11, which is provided with the lateral enlargements shown and which are insulated from each other, contacts the buttons 18, 18 and also the buttons or points 19, 19, and thus current is furished to the

wires

89 and 8|. The motor i6 is connected to these wires by

wires

82, 83. The solenoid 39 of the valve 28 is connected to the wire 8| by a wire 84. From the solenoid Si! a wire 85 leads to the mercury switch 3|. A wire 95 leads from that switch and is connected to the main wire 89. A wire v81 connects the mercury switch 32 to the wire 86. A wire 88 leads to the solenoid 29 of the valve 21, and a wire 83 connects that solenoid to the wire 8 I. A wire 99 connects the wire 8| to the solenoid 34 of the valve 33, and a wire 9| connects the solenoid 34 to the mercury switch 46. A wire 92 connects that switch tothe wire 80, and a wire 93 connects the mercury switch 4'I to the wire 92.

.The wire 94`also connects-the switch 4'I to the solenoid 43 of the valve 42. A wire 95 connects the solenoid 43 to the wire 8|. A wire 96 is connected to the wire 8| and at one end of the wire 96 is connected the solenoid 40 of the valve 38. A wire 91 connects the solenoid 40 to the mercury switch 45, and a wire 98 connects that switch to the wire 80. A wire 99 connects the mercury switch 44 to the wire 98. A wire |00 connects the mercury switch 44 to the solenoid 4I of the valve 39. The wire 96 is also connected to that solenoid. The circuit described is the circuit that is energized during the raising operation. The circuit which isused during the lowering operation will now be described. For lowering, the handle I3 is moved to the position Y and in that position Ait connects the contacts IOI and |02 and also connects the contacts |03 and |04, thus furnishing current to the wires |05 and |06.

v Since the motor is not needed in lowering, it is not connected to this circuit. A wire |01 is connected to the solenoid 30 of the valve 28. A wire |08 connects that solenoid to the mercury switch 32. A wire |09 connects the mercury switchto the wire |06. The mercury switch 3| is connected by a wire IIB to the wire |09. A wire III leads from the mercury switch 3| to the solenoid 29 of the valve 2l. A wire I2 connects that solenoid to the wire |05. A wire ||3 connects the solenoid 53 of the valve 52 to the wire |03, and a wire II4 connects the solenoid 53 to the wire l|05. A wire II5 connects the solenoid 34 of the valve 33 to the wire |05 and the wire II6 leads from the solenoid 34 to the mercury switch 4,'I. A wire I|'I connects the switch 4`I to the wire |06. A wire IIB connects the switch 46 to the wire IIT; and a wire ||9 connects the switch 46 to the solenoid 43 of the valve 42. A wire |20 connects the solenoid 43 tothe wire |05 and to the solenoid 40 of the valve 38. A wire I2I connects the solenoid 40 to the switch 44; and a wire |22 connects the solenoid 44 to the wire |06. A wire |23 leads from the wire |22 to the switch 45. A wire |24 leads from the switch 45 to the solenoid 4| of the valve 39; and a wire |25 connects the solenoid 4| to the wire |05.

Although there is shown an operative form of the device, it will be understood that 'many changes in the form, shape and arrangement of parts might be made without departing from the spirit of this invention, and it is wished that the showing be taken as, in a sense, diagrammatic. In particular, many diierent forms of hoisting means might be used. A mechanical hoisting means might be synchronized and caused to operate at level by the same general control apparatus shown or level controlling devices of many sorts might be used. The mercury valves are suitable and, for many purposes., desirable but other forms of level responsive, circuit controlling means might be used, and the invention is not limited to the use of such mercury switches. While it is convenient to have the sump and the pump and associated parts arranged to rise and fall as the mechanism rises and falls, that is not essential and they might be positioned on the floor or some other fixed b'ase and connected to the rising portion of the mechanism by means of flexible conduits, pipes and the like. Also, the several pistons 2a, 2b', 2c and 2d need not settle upon the same base. One might be higher than the other or any two might be higher than any other two. The leveling mechanism is such that the cylinders "need not all be of `the same size. If desired, the cylinders at one end may be larger vthan those at the other or the cylinders of either pair may be of different sizes.

The leveling means may be used to cause synchronizing or level operation of any number of hoi-sting means; two or any larger number can be synchronized by the present invention. For some purposes, the pairs of mercury valves can be combined into a single valve. Thus, a single specially formed tube might be substituted, for example, for the pairs of tubes 3| and 32 and with the requisite contacts such switches would operate satisfactorily. The invention is, therefore, not limited either to a plurality of switches or to any particular design of switch.

The use and operation of this invention are as follows:

With the parts in the down position and the control handle I3 in the neutral position shown in Figure 6, no current is supplied to the motor and the system is dead and the parts will remain static in Whatever position they have been .left. If the carriage is at the bottom, it will remain so. If it is atl the top or anywhere above the bottom position, it will remain there when the control handle is at the neutral position because liquid cannot pass through the various solenoid valves unless the solenoids are energized. Hence, they remain closed andthe liquid is locked in the several cylinders. I

Assuming the parts in the down position and that it is desired to raise the carriage, the control lever is moved toward the position X of Figure 6 and by means of the contacts I'I current is supplied to the

Wires

80 and 8|. This, While the parts are still level, energizes al1 of the solenoids and thus opens all of the valves. The motor is started, it drives the pump and fluid under pressure is supplied to the pipe 23. It flows tothe pipe 24 and toboth of the righthand cylinders 5. Fluid under pressure also flows to the pipe and to both of the lefthand cylinders 5. Where the words righthand and lefthand are used, this language applies to the showing on

rFigures

1, 2 and 6. So long as the carriage rises in a level position, no further control occurs until it is positively stopped by moving the lever I3 or until it stops in the cylinders 5 to contact the pistonv portions 4. Should excessive pressure develop in the system, the pop-oir valve 2| will be opened and uid under pressure will pass through it and into the sump |I. The pop-off valve is preferably arranged with a chattering means so that, when it is open and fluid is passing through it, it will make a noise and the operator will hear it and will do whatever is necessary to the system.

Should the carriage rise unevenly, the following cycle of operations willoccur:

If the righthand end of Figure 2 rises more rapidly than the lefthand end, the mercury in the switch 46 will flow away from contact with the wires 9| and 92, the solenoid 34 will be deenergized, the valve 33 will close and the supply of fluid under pressure to the righthand cylinders will be interrupted and will remain interrupted until the lefthand end has been raised suinciently to re-establish the level. When that occurs, the mercury in the switch 45 will again contact the Wires 9| and 92, the solenoid 34 will be re-energized, the valve 33 will be opened and fluid under pressure will again ow through the pipe 23 to the pipe 24 for supply to the two righthand cylinders.

Should one side of the frame rise more rapidly than the other, the same general cycle will be carried out. Figure 7 illustrates the righthand end of the diagram shown in Figure 6, and a description of the operation of that end will serve for the corresponding operation at both ends. Assuming that the rghthand side of the carriage-that is, the side supported by the piston 2li-rises more rapidly than the lefthand side, then the mercury in the switch 32 will flow away from the

wires

81 and 88, the solenoid 29 will be de-energized, the Valve 21 will be closed and the supply of fluid under pressure through the valve 21 to the piston 2b will be interrupted and that piston will no longer receive iiuid under pressure. Fluid will continue under pressure to the piston 2a until leveling has occurred and then the mercury in the switch 32 will fiow again to the position of Figure 7, contacting the

wires

81 and 88, re-energizing the solenoid 2S, reopening the valve 21 and recommencing the flow of uid under pressure to the piston 2b.

The general operation described can occur at either end of the system causing a break in the switch 3| or 32 or a break in the

switch

44 or 45 and this may occur repeatedly during a raising operation. Similarly, the same operation may occur when one end is raised above the other and will effect'breaking of the svrltches t6 or 41. The provision of two switches at each control point obviously aifects the valves for the two sides or the two ends to control them and through them to control the flow of fluid under pressure to the respective pistons or cylinders.

When the machine is raised to the desired point, the lever I3 is moved to the inactive position, the motor is stopped, all of the solenoids are de-energized, all of the valves close and there is a fluid lock which prevents accidental or undesired lowering of the carriage.

When 4it is desired to lower the carriage, the control handle I3 is moved to the Y position, and by means of the contact 11, current is supplied to the wires |05, |56 and through them to the other wires forming the lowering circuit, which wires are connected to the several mercury switches and to the several solenoids.

The motor is not energized for lowering because gravity is suicient to force the liquid from the cylinders when the control valves for the cylinders are opened. When current is supplied to the wires |05 and IE5, the

solenoid valves

21, 23, 33, 42, 38 and 39 are opened and the solenoid valve 52, which was not opened during raising, is now opened. The reason for opening the valve 52 is to permit the fluid, as it is forced out of the cylinders, to return through the pipe 50, 5I into the sump II. This valve remains open so long as the control handle is in the lowering or Y position.

The same general leveling operation occurs in lowering as that described in raising but there is, in effect, a reversal of this control from righ-t to left. Considering now Figures 2 and 6, should the righthand end lower more rapidly than the lefthand end, the mercury in the switch 41 will flow out of contact with the Wires H6 and I i8 and will de-energize the solenoid 34, causing the valve 33 to close. Hence, the fluid over the righthand pistons 2a and 2b cannot escape from the pipe 24 into the pipe 23 for return to the sump, and that end of the carriage will stop descending until the lefthand end has caught up to it. When level is restored and the mercury in switch 41 returns to Contact with the Wires IIG and H3, the

solenoid 34 is re-energized to open the valve 33 to permit escape through it.

The lateral leveling is generally similar to that described above and will be described in connection with Figure '1. Should the carriage descend unevenly so that lthe righthand side is ahead of the lefthand side, the mercury in switch 3| will ow out of contact with the Wires IIU and III, de-energizing the solenoid 29, closing the valve 21 and stopping the flow of fluid from above piston 2b. Just as soon as level is restored, -the mercury in switch 3| returns, contacts the wires IIB and I I I, re-energizes the solenoid 29, reopens the valve 21 and permits further return of fluid from above the piston 2b.

The same general cycle of leveling can occur at each end to effect lateral leveling and will occur also .to effect longitudinal leveling.

While the means for synchronizing and controlling a plurality of hydraulic hoists has many uses and is not limited to an automobile or Vehicle lift, the particular embodiment here shown is directed to that purpose. Among the reasons for providing such leveling means are the following: The car or other weight which is to be lifted will very rarely be central with respect to all of the cylinders. The weight will ythus be unevenly distributed. 'Ine car or other weight will very rarely have its center of gravity at its geometrical center. The surface upon which lthe lifting means stand may be uneven; in fact, this surface need not be even. The cylinders themselves need not be of the same diameter. Many other reasons why the automatic leveling is desirable will suggest themselves.

I claim:

l. In combination in a hydraulic lift, a plurality of hydraulic lifting assemblies, each including a fixed part and a relatively movable par-t, and means for supplying fluid under pressure to said hydraulic assemblies, including conduits -to each of them, a carriage supported by said movable parts, and means for controlling the movement of said movable parts to maintain the carriage level, said means including a valve for each of said raising assemblies adapted to control the flow of fluid thereto and therefrom through said conduits, an operating means for each of said valves, a plurality of level responsive devices mounted on said carriage, one of said devices for 4 each of said valve operating means, said devices adapted to be operated when said frame moves out of level to cause one of said valves to be closed, -to alter .the iow of pressure fluid to said raising assemblies until the carriage has been restored to level.

2. In combination in a hydraulic lift, a plurality of hydraulic lifting assemblies, each including a fixed part and a relatively movable part, and means for supplying uid under pressure to said hydraulic assemblies, including conduits to each of them, a carriage supported by said movable parts, and means for controlling the movement of said movable par-ts to maintain the carriage level, said means including a valve for each of said raising .assemblies adapted to control the flow of fluid thereto and therefrom through said conduits, an electrical operating means for each of said valves, a plurality of level responsive electrical switches mounted on said carriage, one of said switches 4for each of said valve operating means, said switches adapted to be operated when said carriage moves out of level to cause one of said valves to be closed, to alter the ow of pressure uid to said raising assemblies until the carriage has been restored to level.

3l In combination in a hydraulic lift, a plurality of hydraulic lifting assemblies, each including a xed part and a relatively movable part, and

means for supplying fluid under pressure to said v hydraulic assemblies, including conduits to each of them, a carriage supported by said movable parts, and means for controlling the movement of said movable parts .to maintain lthe carriage level, said means including a valve for each of said raising assemblies adapted to control the flow of fluid -thereto and therefrom through said conduits, an operating means for each of said valves, a plurality of level responsive devices mounted on said carriage, one of said devices for each of said valve operating means, said devices adapted to be operated when said frame moves out of level to cause one of said valves to be closed, to alter the flow of pressure fluid to said raising assemblies until the carriage has been restored to level, said carriage comprising a longitudinal element and a plurality of transverse elements, a plurality of said level responsive devices being mounted on each of said elements.

4. In combination in a hydraulic lift, a plurality of hydraulic lifting assemblies, each including a fixed part and a relatively movable part, and means for supplying fluid under pressure to said hydraulic assemblies, including conduits to each of them, a carriage supported by said movable parts, and means for controlling the movement of said movable parts to maintain the carriage level, said -means including a valve for each of said raising assemblies adapted to control the flow of uid thereto and therefrom through said conduits, an electrical operating means for each of said valves, a plurality of level responsive electrical switches mounted on said carriage, one of said switches for each of said valve operating means, said switches adapted to be operated when said frame moves out of level to cause one of said valves to be closed, to alter the flow of pressure uid to said raising assemblies until the carriage has been restored to level, said carriage comprising a longitudinal element and a plurality of transverse elements, a plurality of said level responsive switches being mounted on each of said elements.

5. In combination in a hydraulic lift, a plurality of hydraulic lifting assemblies, each including a fixed part and a relatively movable part, and means for supplying fluid under pressure to said hydraulic assemblies, including conduits to each of them, a carriage supported by said movable parts, and means for controlling the movement of said movable parts to maintain the carriage level, said means including a valve for each of said raising assemblies adapted to control the flow of fluid thereto and therefrom through said conduits, an operating means for each of said valves, a plurality of level responsive devices mounted on said carriage, one of said devices for each of said valve operating means, said devices adapted to be operated when said frame moves out of level to cause one of said valves to be closed, to alter the flow of pressure fluid to said raising assemblies until the carriage has been restored to level, said carriage including a longitudinal element and a plurality oftransverse elements, and having a pair of oppositely directed level responsive devices on said longitudinal element and a pair of oppositely directed level responsive devices on each of said transverse elements, the devices on said transverse elements being operated in response to transverse tilting of the carriage and thev devices on the longitudinal element being operated in response to longitudinal tilting of `through said conduits, an electrical operating means for each of said valves, :a plurality of level responsive electrical switches mounted on said carriage, one of said switches for each of said valve operating means, said switches adapted to be operated when said frame moves out of level tocauseone of said valves to be closed, to alter the flow of pressure fluid to said raising assemblies until the carriage has been restored to level,

said carriage including a longitudinal element and 4a plurality of transverse elements, and having a pair of oppositely directed level responsive switches on said longitudinal element and a pair of oppositely directed level responsive switches on each of said transverse elements, the switches on said transverse elements being operated in response to transverse tilting of the carriage and the switches on the longitudinal element being operated in response to longitudinal tilting of the frame.

7. In combination in a lifting means, four fixed pistons, a cylinder upon each of said pistons, a carriage supported by said cylinders, means for introducing Huid under pressure to said cylinders to cause them to rise with respect to said pistons, and means for maintaining said carriage level, comprising means for controlling the supply of pressure fluid to said cylinders, said controlling means including a plurality of level responsive devices, a plurality of valves, one for each of said cylinders and adapted to control the supply of iiuid thereto, a connection from each valve to one of said level responsive devices whereby one of said Valves is operated in response to the operation of any of said level responsive devices. l

8. In combination in a lifting means, four fixed pistons,` a cylinder upon each of said pistons, a carriage supported by said'cylinders, means for introducing fluid under pressure to said cylinders to` cause them to rise with respect to said pistons, and means for maintaining said carriage level, comprising means. for controlling the supply of pressure fluid to said cylinders, said controlling means including a pluralityof level responsive devices mounted on said carriage, a yplurality of valves, one for each of said cylinders and adapted to control the supply of iiuid thereto, a connection from each valve to one 'of said level responsive devices whereby one of said valves is operated in response .to the operation of any of said level responsive devices.

9. In combination in a lifting means, four fixed pistons, a cylinder upon each of said pistons, a carriage supported by said cylinders, means for introducing uid under pressure to said cylinders to cause them to rise with respect to said pistons, and means for maintaining said carriage level, comprising means for controlling the supply of Ipressure uid to said cylinders, said controlling means including a plurality of level responsive devices, some of them positioned to be affected by lateral tilting of the carriage, a plurality of valves, one for each of said cylinders and adapted to control the supply of uid thereto, a connection from each valve to one of said level responsive devices whereby one of said valves is operated in response to the operation of any of said level responsive devices.

10. In combination in a lifting means, four xed pistons, a cylinder upon each of said pistons, a carriage supported by said cylinders, means for introducing fluid under pressure to said cylinders to cause them to rise with respect to said pistons, and means for maintaining said carriage level, comprising means for controlling the supply of pressure fluid to said cylinders, said controlling means including a plurality of level responsive devices, some of them positioned to be affected by longitudinal tilting of the carriage, a plurality of valves, one for each of said cylinders and adapted to control the supp-ly of fluid thereto, a connection from each valve to one of said level responsive devices whereby one of said valves is operated in response to the operation of any of said level respo-nsive devices,V

1l. In combination in a `lifting means, four fixed pistons, a cylinder upon each of said pistons, a carriage supported by said cylinders, means for introducing fluid under pressure to said cylinders to cause them to rise with respect to said pistons, and means for maintaining said carriage level, comprising means for controlling the supply of pressure fluid to said cylinders, said controlling means including a plurality of level responsive devices, some of them positioned to be affected by lateral tilting of the carriage, others positioned to be affected by longitudinal-tilting of the carriage, a plurality of valves, one for each of said cylinders and adapted to control the supply of fluid thereto, a connection from each valve to one of said level responsive devices whereby one of said valves is operated in response tothe operation of any of said level responsive devices.

12. In combination in a lifting means, four xed pistons, a cylinder upon each of said pistons, a carriage supported by said cylinders, means for introducing fluid under pressure to said cylinders to cause them to rise with respect to said pistons, and means for maintaining said carriage level, comprising means for controlling the supply of pressure fluid to said cylinders, said controlling means including a plurality of level responsive devices mounted on said carriage, some of them positioned to be affected by lateral tilting of the carriage, others positioned to be affected by longitudinal tilting of the carriage, a plurality of valves, one for each of said cylinders and adapted to control the supply of iluid thereto, a connection from each valve to one of said level responsive, devices whereby one o-f said valves is operated in response to the operation of any of said level responsive devices.

13. In combination in a lifting means, four fixed pistons, a cylinder upon each of said pistons, a carriage supported by said cylinders, means for introducing fluid under pressure to said cylinders to cause them to Arise with respect to said pistons, and means for maintaining said carriage level, comprising means for controlling the supply of pressure fluid to said cylinders, said controlling means including a plurality of level responsive electrical switches, some of them positioned to be affected by lateral tilting of the carriage, others positioned to be affected by longitudinal tilting of the carriage, a plurality of valves,

one for each of said cylinders and adapted to control the supply of fluid thereto, a connection from each valve to one of said level responsive switches whereby one of said valves is operated in response to the operation of any of said level responsive switches.

14. In combination in a lifting means, four xed pistons, a cylinder upon each of said pistons, a carriage supported by said cylinders, means for introducing fluid under pressure to said cylinders to cause them to rise with respect to said pistons, and means for maintaining said carriage level during movement, comprising means for controlling the supply of pressure uid to said cylinders, said controlling means including a plurality of level responsive electrical switches mounted on said carriage, some of them positioned to be affected by lateral tilting of the carriage, others positioned to be affected by longitudinal tilting of the carriage, a plurality of valves, one for each of said cylinders and adapted to control the supply of fluid thereto, a connection from each valve to one of said level responsive switches whereby one of said valves is operated in response to the operation of any of said level responsive switches.

15. In combination in a lift, a plurality of hydraulic lifting means, each of said means including a fixed member and a movable member, a carriage supported by said movable members, and means for supplying pressure uid and for controlling the supply of said pressure fluid to said raising means in response to tilting of said carriage, whereby said carriage is retained substantially level, said means including a source of fluid under pressure, conduits -supplying said fluid to each of said raising means, a valve for eachf of said conduits, a plurality of level responsive means upon said carriage, said level responsive means being connected to each of said valves whereby tilting of the carriage inv any direction affects one of said valves to cut olf supply of fluid to the leading, raising means.

16. In combination in a hydraulic lifting apparatus, a plurality of hydraulic lifting assemblies, each including a fixed part and a relatively movable part, a carriage supported by said movable parts, means for supplying fluid under pressure to said lifting assemblies and for Withdrawing fluid from said assemblies, and means for controlling the withdrawal of fluid from said assemblies to maintain the carriage level, said controlling means including a valve for each of the raising assemblies adapted to control the iiow of fluid therefrom; an operating means for each of said valves, a plurality of level responsive devices mounted on said carriage, one of said devices for each of said valve operating means, said devices adapted to be operated when said frame moves out of level to cause one of said valves to be closed and thereby to alter the flow of fluid from said raising assemblies until the carriage has been restored to level.

17. In combination in a hydraulic lifting apparatus, a plurality of hydraulic lifting assemblies, each including a iiXed part and a relatively movable part, a carriage supported by said movable parts, means for supplying fluid under pressure to said lifting assemblies and for Withdrawing fluid from said assemblies, and means for controlling the withdrawal of fluid from said assemblies to maintain the carriage level, said controlling means including a valve for each of the raising assemblies adapted to control the flow of fluid therefrom; an operating means for each of said valves, a plurality of level responsive devices mounted on said carriage, one of said devices for each of said valve o-perating means, said devices adapted to be operated when said frame moves out of level to cause the valve controlling the hydraulic lifting assembly which has lowered more rapidly than another to be closed and to stop the flow of fluid from said leading assembly until the carriage has been restored to level.

18. In combination in a hydraulic lifting apparatus, a plurality of hydraulic lifting assemblies, each including a xed part and a relatively movable part, a carriage supported by said movable parts, means for supplying fluid under pressure to said lifting assemblies and for withdrawing uid from said assemblies, and means for controlling the withdrawal of fluid from said assemblies to maintain the carriage level, said controlling means including a valve for each of the raising assemblies adapted -to control the flow of fluid therefrom; an operating means for each of said Valves, a plurality of level responsive devices mounted on said carriage, one of said devices for each of said valve operating means, said devices adapted to be operated when said frame moves out of level to cause the valve controlling the hydraulic lifting assembly which has lowered more rapidly than another to be closed and to stop the ow of fluid from said leading assembly until the carriage has been restored to level, and to reopen the Valve when the frame has been restored to level for further discharge of pressure uid from the assembly from which discharge was temporarily checked.

19. In combination in a hydraulic lift, a plurality of hydraulic lifting assemblies,`each including a xed part and a relatively movable part, and means for supplying uid under pressure to said hydraulic assemblies, including conduits to each of them, a carriage supported by said movable parts, and means for controlling the movement of said movable parts to maintain the carriage level, said means including a valve for each of said raising assemblies adapted to control the flo-W of fluid thereto and -therefrom through said conduits, and operating means for each of said valves, a level responsive device mounted on said carriage and provided with operating connections to each of said valve operating means, said device adapted to be operated when said frame moves out of level to cause one of said valves to be closed, to alter the ow of pressure uid to said raising assemblies until the carriage has been restored to level.

20. n combination in a hydraulic lift, a plurality of hydraulic lifting assemblies, each including a fixed part and a relatively movable part, and means for supplying fluid under pressure to said hydraulic assemblies, including conduits to each of them, a carriage supported by said movable parts, and means for controlling the movement of said movable parts to maintain the carriage level, said means including a valve for each of said raising assemblies adapted' to control the flow of fluid thereto and therefrom through said conduits, `an electrical operating means for each of said valves, a level responsive electrical switch mounted on said carriage, said switch having a contact member for each of said valve operating means, and a connection from one of said contact members to the corresponding valve operating means, said switch adapted to be operated When said carriage moves out of level to cause one of said valves to be closed.

WILLIAM C. ANTHONY.