US2553045A - Pump and motor hydraulic system - Google Patents

Description

May 15, 1951 L. F. JAsEPH 2,553,045

PUIIP AND -MOTOR HYDRAULIC SYSTEM Filed Oct. 24, 1942 7 Sheets-Sheet l Index/Zar, y [alare/0 c@ Mge/w72' May 15, 1951 1 F. JAsEPH PUMP AND MOTOR HYDRAULIC SYSTEM 7 Sheets-Sheet 2 Filed Oct. 24, 1942 May 15, 1,951 l.. F. JASEPH PUMP AND MoToR HYDRAULIC SYSTEM 7 Sheets-Sheet 5 Filed Oct. 24, 1942 May 15, 1951 L F, JASEPH 2,553,045.

PUMP AND MOTOR^HYDRAULIC SYSTEM Filed Oct. 24, 1942 7 Sheets-Sheet 4 May 15, 1951 L. F. JAsEPH 2,553,045

I PUMP AND MOTOR HYDRAULIC SYSTEM Filed Oct. 24, 1942 7 Sheets-Sheet 5 L. F. JASEPH PUMP AND MOTOR HYDRAULIC SYSTEM May 15 1951 '7 Sheets-Sheet 6 Filed Oct. 24, 1942 o; O fw lag May 15, 1951 L. F. JAsEPH v 2,553,045

Puur Ama uo'ron HYDRAULIC sys'ma Filed Oct. 24, 1942 '7 Sheets-Sheet '7 27d a I M@ IFT J 1 33 60 Z 23g( i 502 :fd 50,41 gf o Ja@ i' 5/0 2f s l! Zg I, 5 J/.z

2XZ- o f zo@ Q. E ze ffy. 3/6 /f zo@ Z' V, /f 50o l a 26k* 206 4 301 570 /24 203 i Q6 ,/z 36 J0 w 442 3 l *alega 200 E 532/ /o 154 /08 t 550 #a I6 l 12a 28 173/92 a1/2 @X v l5 a//o :[74 u im ya l 50 my /80 ,/za X50 132 .f5/24156 ,/90 /f 5o v/HAMGTZ Patented May 15, 1951 PUMP AND MOTOR HYDRAULIC SYSTEM Lawrence F. Jaseph, Memphis, Tenn., assignor to Rotary Lift Company, Memphis, Tenn., a corporation of Delaware Application October 24, 1942, Serial No. 463,191

29 Claims.

The present invention relates to improvements in hydraulic control andi more particularly to improvements in control valves for hydraulically actuated devices such, for instance, as elevators. The present invention is an improvement over the invention disclosed in mycopending application, Serial No. 377,959, led February 8, 1941 (now Patent No. 2,355,164, granted August 8, 1944).

The present invention relates primarily to a control valve for hydraulic elevators that are raised by pressure obtained directly from a motor driven pumpv and lowered by gravity. The valve enables elevators of this type automatically to be controlled in such a manner as to obtain gradual smooth acceleration and deceleration when the elevatorl is either raised or lowered; to provide a plurality of speeds in both directions, one of which is a slow Speed enabling landings to be made accurately and enabling the elevator to be moved small distances; to provide gradual stopping of theelevator in the event of a power failure; to limit the hydraulic pressure to a safe maximum value; and to permit the pump driving motor to be started and accelerated to full speed with but a very small load.

One of the objects of the invention is to provide a new and improved control valve for a hydraulically actuated device supplied with fluid from a motor driven pump so constructed and arranged as to enable the motor to be started and accelerated to full speed with but a very small load.

Another object of the invention is to provide a new and improved control valve capable of .limiting the pressure obtaining in the system and applied to the actuated device to a safe maximum value.

A further object of the invention is to provide a new and improved control valve wherein a valve member of unitary construction provides both the motor starting and pressure limiting features to which reference has been made.

A further object of the present invention is the provision of a new and improved valve of the character described capable of effecting smooth and gradual acceleration and deceleration of the actuated device and, further, wherein the valve member of unitaryv construction is utilized to provide not only the motor starting and pressure limiting constructions, but also acceleration and deceleration when the actuated device is moved by pressure obtained from the motor driven pump.

Anotherl object of the present invention is the provision of a new and improved control valve of the character described capable of controllingthe ow of fluid from the pump to the actuated. device to effect movement of the device in one direction and from the actuated device to a fluid reservoir to effect movement of the device in the opposite direction.

A further object. of the present invention is the provision of a new and improved valve of the type last mentioned with means for indicating both the volume-and direction of theflow of fluid.

A still further object of the present invention is the provision of anew and improved Valve of this type wherein the indicating means is utilized in controlling the valve so as to produce a constant iiow of uid to the. actuated device.

A further object of the present invention is to provide a control valve of the character described with movement restraining means so controlling the valve that flow of fluid to and' from the actuated device can beV effected at a uniformly changing rate.

Another object of the present invention is the provision of a valve ofthe character described that is controlled by a pilot valve andV wherein the pilot Valve is so controlled that during a period of operation the flow through the valve is at a uniformly changing rate and wherein in case the rate departs from this uniformly changing rate, the pilot valve is controlled to bring back the rate to this uniform value.

A further object of the present invention is to provide a new and improved control valve including a combined pilot operated bypass valve and an overpressurev relief valve of the spring biased type wherein the same structural parts are used to perform both functions without interference, and wherein it is not necessary to relax the relief valve spring when the bypass is opened.

A further object of the present invention is the provision of a new and improved overpressure relief valve.

Other objects and advantages of the present invention will Ibecome apparent from the ensuing description, in the course of which reference is had to the accompanying drawings in which:

Fig. 1 is a diagrammatic illustration showing how the present invention may be applied to one type of elevator system;

Fig. 2 is a diagrammatic illustration of electrical circuits embodied in the system shown in Fig. 1 to illustrate how the present invention may be applied to one type of system;

Fig. 3 is a top plan view of the control valve of the present invention which forms an important part of the system illustrated in Figs. 1 and 2;

Fig. 4 is a side elevational view of the control valve;

Fig. 5 is an enlarged cross-sectional view of the valve, the View being taken along the line 5-5 of Fig. 3 and also along line 5-5 of Fig. 6;

Fig. 6 is a View similar to Fig. 5, the view being taken along the line 6 6 of Fig. 5;

Fig. 7 is an enlarged fragmentary cross-sectional view, the View being taken along the line 'l-'I of Fig. 3;

Fig. 8 is an axial cross-sectional view through a pilot valve forming part of the main control valve illustrated in the preceding figures;

Fig. 9 is a top plan view, with cover removed, of the structure within the control box located at the right of Fig. 3;

Fig. 10 is a side view of the structure within the control box, a portion of the structure being omitted better to illustrate other details of construction; and

Fig. '11 is a diagrammatic view showing in schematic form the operative relation of the several elements of this control system.

Before 'proceeding with a detailed description of the control valve forming the primary feature of the present invention, it may be well briey to describe one type of elevator installation embodying the control valve. In so doing, reference will be had vto Figs. 1 and 2 illustrating the mechanical and electrical features, respectively, of one type of system to which the valve may be applied. This system is of the type controlled by a manually controlled car switch, but it should be understood the system is but one of a number to which the valve of the invention may be applied. The valve may be readily adapted to automatic control systems of the momentary or constant pressure push-button controlled type, and also to systems having automatic leveling, as will become apparent from the following description.

Referring first to Fig. 1, it may be noted that the elevator car l0 is supported at the top of a plunger YI? mounted for vertical reciprocating movement in a cylinder I4. The elevator is raised by supplying fluid, preferably oil, under pressure to the cylinder and the elevator is lowered by gravity by allowing the oil to ow from the cylinder into a reservoir. Y

Oil is supplied to the cylinder under pressure by means of a pump I6 of the constant displace ment type and driven by an electric motor i8. Oil is supplied to the suction side of the pump from a reservoir through a conduit 22 and the discharge side of the pump is connected through a conduit 24 to the control valve 26 of the present invention. The control valve is connected by a conduit 28 to the elevator cylinder M and by a conduit 30 to the reservoir.

The movement of the elevaor in the illustrated system is controlled by a'car switch 32 mounted within the elevator and operable from a neutral or stop position into high and low speed positions for Veither raising or lowering the elevator at high or low speed. The elevator control includes also normally closed upper and lower limit switches 3d and 36 opened at limits of movement by a switch operating member 31 secured to the car. The various switches are connected electrically in the manner shown in Fig. 2, the electrical conductors being enclosed in suitable conduits 38 of which the portion 40, connected t0 the car switch, is flexible. In the instant case, the elevator is shown as being movable between an upper landing 42 and a lower landing 4d. It should be understood, however, that the number of landings will depend upon the particular installations of the elevator. Power is supplied to the motor and to the controls from a suitable source through a manual control switch 46 from which a conduit leads to a'control box 48 including an electromagnetically operated motor switch.

Referring now to Fig. 2, it may be seen that the pump motor i3 is of the three-phase type and that its energization is controlled by a switch 50 operable by a solenoid 52, these being mounted in the control box 48. The motor, as already indicated, is utilized only when it is desired to raise the elevator, as the lowering of the latter is efiected'by gravity.

The control valve 26 of the present invention includes four solenoids that are selectively energized tc effect raising and lowering of the ele vater at high and low speeds. These solenoids are indicated by reference characters 54, 56, 58,

and 68. When it is desired to raise the elevator y 54 or 56 is energized and to accomplish this, the

solenoids are each adapted to' close a switch 62 in series with the solenoid 52 across two of the power lines. "Consequently, when' either of the solenoids is energized, the pump motor I8 is also energized. f

The solenoids are selectively energized byv thel car switch which has beenillustrated but diagrammatically. 'As the car switch handle 64 is moved in aV counte'rclockwise direction to a rst position, the solenoid 54 is energized to effect raising of the elevator at low speed. The sole; noid is energized through a circuit including conductor 66, the upper limit switch 34,"conductor 63, car switch 32, conductor 16, the 'solenoid 511, and conductor '12. If it is desired to raise the elevator at high speed, the car switch handle 64 is moved further in a counterclockvvise direction, thereby deenergizing solenoid 54 and energizing solenoid 56, the latter being energized throughv a circuit corresponding to that for solenoid 54 except that the circuit extends through a conductor 'Hl instead of conductor 10.

To lower the elevator at lowAspeed, the control handle 6d is moved in a clockwise direction. In a rst position the solenoid 5B is energized to effect lowering of the elevator at slow speed. The solenoid is energized through a circuit including the conductor 66, a conductor 'F6 leading to the lower limit switch 36, conductor 78, the car switch, conductor 66 leading to the solenoid, and conductm1 l2. In a further clockwise position, the solenoid Si) is energized through a similar circuit except conductor 82 is substituted for the conductor B6. If desired, fuses 34 may be located in the control circuits for safety purposes.

Before proceeding with a description of the details of the control valve, it might be well briefly to set forth the main details of its conA struction and operation in a system suchasv that described. The valve assembly itself comprises primarily a check vvalve for preventing Yreturn flow of oil' from the elevator cylinder to thedischarge side-ofthe pump, a. bypass valve for bypassing the oil? from the discharge of the pump to the oil reservoir, a lowering valve, a. mechanism for indicating the direction and volume of oil flowing throughthe valve (that is, oil flow to the cylinder from the pump or from the cylinder to the reservoir), a pilot valve controlling the bypass and lowering valves, the four valve control solenoidsf referred to, movement restraining devices, preferably dash pots, and suitable linkage mechanism for connecting the pilot valve to the-solenoids and indicating mechanism.

To raise the elevator, the pump motor lil is energizedfby energization of either one or the other of the solenoids 54-and 5t". The bypass valve is normally openl so that whenever the motor is started, it accelerates and brings the pump up to full speed very quickly and at a very light load sincethe-oil is bypassed at a very low pressure. After a time delay' determined by the setting of the dash pots, the pilot valve moves to a position such that the bypassvalve is gradually closed by an increasing oil pressure so that oil is gradually supplied to the elevator cylinder. continues until the bypass is fully closed.

To stop the elevator when it is moving in an upward direction, the solenoid 54 or 56, whichever-is energized at the time, is deenergized. The

motor, however, continues to operate and the bypass is gradually opened. When the bypass opens to a sufficient extent, the elevator stops` and the motor is deenergized'by the opening of the switch, this being the switch 62..

Ifa slow raising speed is desired at any time, ther solenoid' is energized. It operates to open thev bypass to but a limited extent, whereby all but a definite quantity of the oil is bypassed to the reservoir.

Tolower the elevator at high speed, the solenoid 6B is energized; It operates the pilot valve to a position such that the lowering valve is permitted to open to a desired extent corresponding to the desired speed. The lowering valve is automatically-maintained at this opening. To reduce the lowering speed to.v a goodl leveling rate, the solenoid 6E!" is deenergized` and the solenoid 58 energized.v The main lowering. valve then closes gradually to a position to produce the desired low speed where it remains until the solenoid 58 is deenergized. When this is done, the lowering valve gradually closes and brings the elevator to rest.

It may be noted, therefore, that the control valve may be readily controlled to effect raising or lowering of the elevator at either high` or low speed. It thus lends itself not only to the illustrated manual type of control, but also to other types of manual control and to automatic control whereinthe elevator is operated athigh speed except in landing zones, at. low speedin the landing zones and also automatically leveled, even if it should, for any reason whatever, go past some predetermined stopping point. The valve may be remotely controlled and easily controlled by the manual control and control members, such as switches positioned to be controlled in response to the car position.

Referring now more particularly to Figs. 3 to 5, inclusive, it may be noted that the control valve 26 comprises a casing or body Sill in the form of casting provided with an inlet port 92 to which the pump discharge conduit Ztl is connected, an outlet port 94 (see Fig. 3) to which the conduit Si! leading to the reservoir is connected, and what This action between passageway 98 and chamber Ht.

may be termed. a combined outlet and return port fthrough which oil flows to and from the elevator cylinder lll through conduit 2%. When the elevator is being raised, oil flows from the discharge side of the pump through the port 92 into a passageway 98, past a pivotally mounted gravity biased checkA valve Hill, into a chamber |92, and then past. an oscillatable vane lil, hereinafter to be referred to as a speed vane and the purpose and functioning of which will be described in greater detail, into a chamber |06 and through the port SG and conduit 28 to the cylinder. When the elevator being lowered, oil ows from the cylinder into chamber Ii through the port. 96, andv then past the speed vane HM into chamber H22, and past a then open lowering valve it into a. return chamber I mand thence to the reservoir through port se and conduit .30. During the lowering operation, the check valve li is closed to prevent return ow of oil to the discharge side of the pump.

The main operatingparts of the valve mounted within the valve casing, other than the check valve |06 and speed vane it, are the lowering valve lili!- and a bypass valve H2. This bypass valve l2 is utilized when starting the pump motor, during the raising'o the elevator, and also in providing overpressure relier".

Under normal conditions, i. e., when the elevator is stopped, the various operating parts cccupy the positions in which they are indicated in Figs. iand 6. At this time, the check valve is closed, speed vane is in its central position to which it is resiliently biased, the lowering valve H33 is in' closed position shutting o communication between chambers its and l Iii, and the bypass valve is open providing communication between the passage 93 and the return chamber Referring now more particularly to Figs. E and 6; it may be seen that the bypass valve M2 comprises a cylindrical valve H4 defining p0rtion, the reduced inner end H of which :Tits closely in a port ||8 providing communication It is provided with radial passages |20 which, in the indicated position of the valve, permit full flow of liquid from port l I8 to the return chamber i i@ without necessity of the valve being completely 'withdrawn from its seat. The opposite end of the valve is enlarged'rto-form a piston |22 closely tting in and reciprocable in a cylindrical piston chamber |26 formed in the body t. The piston chamber is sealed by a closure cap l2@ secured to flanges surrounding the piston chamber by any suitable means such as the bolts 28 shown in Fig. 6. Movement of the piston to the left, that is, toward the closure cap, is limited by the cap, againstA which a peripheral shoulder i3@ on the piston is adapted to abut.

The' bypass valve is biased toward its open position by a relatively light spring |32, which holds the piston against the closure cap or against a suitable stop ring (not shown, but which may be provided if it is desired to further limit the movement of the piston i'or purposes of adjustment when required).

The closure cap and left end of the piston deline a' pressure chamber |34, the pressure in which is controlled by a pilot valve, to be described hereinafter, in order to control the movement and position of the bypass valve. rThe pressure chamber communicates with the port ll and passageway 58 through one or more (only one being shown) passages |36 extending 7 through the piston. The pressure chamber also communicates with the pilot valve through a conduit communicating with the chamber through a nipple suitably secured to the closure cap.

The overpressure relief is provided by a second valve defining piston |42 movable within a smaller piston chamber |44 formed in the piston |22. The piston |42 is normally biased outwardly by a relatively heavy spring |46 whereby the piston closes one or morepassages |48 (only one being shown) in the larger piston. When excess pressures obtain in the system, the pressure in chamber |34 is sumcient to move the piston |42 inwardly against the spring to uncover these passages whereby the pressure existing in the chamber |34 is relieved by the ow of oil into the return chamber ||0 and consequent opening of the bypass valve. In the event the excess pressure is not particularly great, the piston |42 uncovers but a small area of the passageway |43, this small area being provided by a tapered portion |50 formed near the outer end of passageway |48. Thus, small movement of the piston |42 will uncover but a small passage for'escape of liquid but a greater movement will open a relatively large area for the escape of the liquid and rapid relief of pressure in the system.

The pressure at which overpressure relief is obtained may be adjusted by varying the coml' pression of the spring |46. This compression is varied by means of an adjusting screw |52 which is held in adjusted position by a lock nut |54. The inner end of the adjusting screw'bears against a cupped washer |56 bearing against the cuter end of the spring. Inward movement of the piston is limited by a shoulder |50 in the piston |22 and outward movement by a snap ring i60 inserted in a groove in the piston |22.

The relief valve of the present invention is particularly advantageous in that the spring |46 is preloade'd so that it will not be compressed materially as a result of pressures obtaining in the system until the pressures reach overpressure values. Even in this case the additional compression of the spring is slight. As a result, the spring is extremely unlikely to be broken as a result of fatigue. While the relief valve has been illustrated as embodied in a particular control valve, it should be understood that it is adapted to be used alone or in conjunction with other types of valves. v

The lowering valve is best illustrated in Fig. 6, to which reference will now be had. It comprises a piston |64 tting closely and reciprocable in a piston chamber |66. The piston carries a hard resilient disk |68 retained in place by a throttling cup |10 secured to the disk by a screw |72. The throttling cup assists in guiding the piston as it is fitted closely in a seat |14 formed in a partition |76 separating the return reservoir |20 from the chamber |02.

The lowering valve is normally closed, it being urged in closing direction by a relatively light spring V58 abutting against the outer face of the piston and against a closure cap |80 secured to anges in the valve body by suitable means such as the bolts |82. A pressure chamber |84 is derlned by the outer side of the piston and the closure capp.l This chamber communicates with chamber |02 through one or more (only one being shown) passages |86 preferably formed in inserts |88 threaded into the piston.

The position of the lowering valve is also controlled by regulating the pressure in Athe lli 8 chamber |04. This pressure regulation is also effected by the pilot valve which is connected to the pressure chamber by a conduit |90 communieating with the pressure chamber through a nipple |92 secured to the closure cap.

The speed indicating vane |04 is movably mounted at the upper end of the valve body, as best illustrated in Figs. 5 and 7. The vane is rectangular in shape and is tted closely but freely to move in a semi-cylindrical opening |94 in the valve body. The described construction provides two generally V-shaped ports, |96 and |98 separated by a partition 200. The va-ne is preferably mounted in a closure cap 202 secured to the valve body as by a plurality of bolts 2044 (see Fig. 3). The vane |04 is secured to a shaft 206 by a pin 208 and shaft 206- is mounted Vfor oscillation in a pair of spaced apart bearings 2|0 mounted in the closure member. Leakage of liquid along the shaft is prevented by-resilient packing 2|2 and endWise movement of the shaft is prevented by thrust collars 2| 4 and 2|6, the latter of which is threaded into the closure'member and provided with a recess to receive a collar Zig formed on the shaft.

The speed vane is biased toits central position (in which it is indicated in Figs. 5 and 7) by a spring 220, shown best in Fig. 9. When the speed vane is displaced in either direction from its centered position, the spring tends to ret-urn it with a positive force by reason of the spring being placed under considerable initial tension,

as will be described shortly.

Inasmuch as the ports |96 and |98 are generally V-shaped, it may be seen that a small rotation of the vane uncovers only a small port area, but greater rotation uncovers a greate portion of the port. I" The various controls, including the solenoids and bypass valve, are mounted in or secured to a control box 222. The control box comprises generally Vertical and horizontal bed plate walls 224 and 225 and a removable cover 228. Itis secured to the valve body by a plurality of screws 230 (see Fig. 4) passing through wall 224.# g-

The previously referred to pilot valve, which is indicated generally by the reference character 232, is mounted underneath the wall 'portion 226'by a plurality of bolts 234. The pilot valve is controlled, as already indicated, byl the selectively energizable solenoids 54, 56, 58, and 60, and also by the speed vane |04, all of which are connected to the pilot valvethrough a linkage mechanism now to be described. i

Each of the solenoids includes a winding semost supports 23B and 240 extend above the llinermost supports and fixedly support a shaft 2 42 upon which is journaled a pair of levers indicated generally by reference Acharacters 244 and 246.

The plungers 243 of the four solenoids are connected to the lever 244, whereby the latteris rotatable in opposite directions depending upon Whether the raising solenoids 54 and 56, or the lowering solenoids 58 and 60 are energized and to different angular 'extents depending upon whether the high speed solenoids 56 and 60, :vor the low speed solenoids 54 and 58 are. energized. The `plungers are adjustably connected tothe lever by identical structures so that it is thought necessary to describe butvone of K these and to 9 indicate the others by .like reference characters. Referring now more particularly to Fig. 9, it may be seen that the lever 244 has oppositely extending arms 250 and 252, each of which terminates in a short reversely extending .portion spaced from lan outwardly extending portion. Transversely extending pins '254 are xedly secured to the outwardly and reversely extending portions of the lever arms at equal distances from the axis of rotation ci the lever. These pins are Yutilized operatively .to connect the lever to the solenoid plungers 248, the latter being h-ingedly connected at their upper ends to connecting links 256 by pins 25S extending through the links and plungers. The connecting links are slotted near their Vupper ends as indicated by the reference character 250 (see Fig. 10) to receive the pins 254 and the upper ends of the `links are tapped to receive adjusting lscrews 262 held in vadjusted posit-ion l Thus, by-adjusti-ng the screws by yjam nuts 264. 252, the lower ends of which bear lagainst the pins '254, the location ofthe plunger relative to the lever may be Varied to control the angular movement of the lever by the solenoids.

lever 244 are so constructed and arranged that 'when either of solenoids 54 or`56 'isenergized the lever is yr-ocked in `a counterclookwi'se v(looking at Fig. 10) direction, the solenoid 56 rotating the lever la greater extent than solenoid 54. When either 0f solenoicls 58 or 60 is energized, the lever is rocked in the opposite or clockwise direction, the solenoid @G rocking the lever to a greater extent than the solenoid 58.

When any of the solenoids is energized, the resulting movement of the lever 244 is vtransmitted to the lever 246 through a resilient connection including a spring 214 and opposed pins 2'16 and 218 xedly secured to upwardly extending bosses formed in levers 244 and 242, as best indicated in Figs. 9 and 1'0. The spring 214 is wound about an extension 286 of the hub of lever `244, and the ends of the spring embrace the two pins in a vmanner similar to that in which the ends of spring 268 encircle the pins 210 and 212. The spring 214 serves also normally to bias the lever 246 to a horizontal position but whenever the lever 244 is rotated by the solenoids, the lever 245 is rotated in the same direction through the resilient connection.

The rotation of the lever 246` is made to be gradual and at a uniform rate by means of two dash pots 282 (only one of which has been shown in Fig. 10 better to illustrate other features), which are provided with air bleed Valves 284 for adjusting the rate of movement. The lever 24e` is connected to the vdash pots by means of its opposed arms 286 and downwardly vextending llinks 288 pinned vat their upper ends to the arms 286 and at their lower ends to the pistons 290 of the dash pots.

The 'lever 246 is operatively connected to the pilot valve l232 vby means of 'an arm 202 hingedly ysecured to a downwardly extending link 294, the `lower end of which is h'i'ngedly connected vto a The i connecting links 260 are held in place on the 10 two-part'floatinglever 236 which inturn is hingedly connected by a pin .298 .to the upper en'd 300 ofthe reciprocable tubular .pilot'valve piston "33|, The arm 2320i the lever 246 is spaced from the arms 286, as best illustrated in Fig. 9, and it 'isfprovided with .an integral cam d'ening'extension '302 operating the Lpreviously .referred `:to .switch 62. The 'switch .62 is of the normally closed type :and operated upon movement .of a ilexible switch actuating member 304 'engaging a switch Abutton .306 and to the upper end of which is secured a roller 308 engageable with .the cam .defining portion A302. The camis-so shaped land arranged relative to the .roller that in its normalyposition or 'when rotated clockwise (as viewed in Fig. l0) pressure is maintained on `y.the roller `and nexible .portion 304 to .maintain ythe switch "32 open. However, a slight counterclock- 'wif-3e 'rotation of the cam 302 removes .the vpressure whereby the flexible member 304 .moves outwardlyand 'permits .the switch to close.

The lever 246 is counterbalanced by fa weight to extending therefrom in a direction opposite to the arm 292.

The .speed vane .|04 is valso connected 'to the V.-iioatiir'g lever .296 by means of which the .pilot 'valve is controlled. This connection extends from the speed vane shaft 206 to the foating lever Ythrough a lever .f3 I2 iixedly secured by 'a 'pin 3`|r3 `to theshaft 206 `and the slotted end 3|4 of -which 'is hingedly .secured Ato the upper end of 'a link 3i6 having its lower end lhingedly secured tothe heating-lever. As already indicated, `the shaft 206 and consequently the lever -3|2 is Abiased to anormal (horizontal) .position in which -it is indicated in Figs. 9 and 1.0 by the spring l22|). The spring is wound aroundthe end of the thrust collar 2 I3 extending into the control box through the bed .plate wall 224, as illustrated Ybest in rFig. 9. The ends of the spring embrace a pin 3.!"8 secured tothe .bed plate walland .thegrooved lend 320 of the lever 3|2.

The pilot valve `1232 and its connection to Lthe Voating lever 296 vare best illustrated in'FigS. 8

and l0 to which reference will now .be had. Re'- `eri'ing more particularly to Fig. 8, Ait may be seen that `tubular piston- 3|l| is connected viby -a threaded joint to the upper portion 300 connected to the floating lever. .The -connection between '.the two parts of the .piston is sealed vby a flexible sealing diaphragm 322 -held -in place at its center by a collar :324 formed integrally with vmember 300. The outer peripheral Iportion of the sealing diaphragm is held between .the body of the pilot valve and the bed plate wall 226 by the previously referred to .securing screws 234. A small passageway 326 provides'communication between the interior `of the valve piston 30| and the diaphragm to balance the pressures .acting on the piston. The pilot valve controls the pressures .existing within the pressure chambers |34 and |84 .of .the vbypass'and lowering valves, respectively, bycontrolling the flow of oil from these chambers to the return passage "|I0. Under normal conditions, the bypass Valve pressure chamber is connected to the return chamber Vbut the Apressure chamber of the lowering valve is cut oi from communication with the return chamber. The bypass pressure chamber is connected to the pilot valve through the previously referred to conduit |38 and a suitable coupling 32B leading to an annular port 330 formed inthe body of -th'e pilot valve. Under normal conditions, the lower end of the pilot valve piston 30| is a position to open this port whereby the pressure chamber communicates with the return chamber through the conduit |38, the port 333, an outlet port 332 formed at the lower end of the pilot valve body, and a conduit 334 leading to the return chamber through a coupling member 33t, as illustrated in Fig. 4. Under normal conditions, the flow cf liquid from the lowering valve lpressure chamber |84 is cut off by the pilot valve, thev lower end of which closes a port 338 con- Vnected to the pressure chamber through the conduit i90. When the elevator is being raised, the closing of the port 330 is controlled by the piston 30| which, in turn is controlled conjointly by one or the other of solenoids 54 or 56 and the speed vane, and when the elevator is being lowered the opening or" port 333 is similarly controlled by the piston under the conjoint control o one or the other of solenoids B or 6B and the speed vane.

Before considering the operation of the'system when raising and lowering the elevator, it may .be well first to set forth the normal positions of the various parts of the system. Thus when the felevator car switch 32 is in its neutral position, wherein it is indicated in Fig, 2, the various pilot valve operating valve solenoids 54, 56, 58, and Sii are alldeenergized. The switch 62 is, therefore, :open and the motor switch controlling solenoid 52 is'deenergized so that the pump motor and lpump are out of operation. Under these conditions, the check valve |90 is closed and the speed yvane is at its normal position, as indicated in Fig; 5. The lowering valve |08 is closed by reason or the force exerted thereon by its biasing Aspring |18 and by the pressure existing in chamber |84, the ow of liquid from which is preyvented by the normally closed pilot valve port 338. The bypass valve is open by reason of the force exerted thereon by the relatively light spring |32 and because the pressure chamber |34 is under no pressure since the liquid therefrom isz-permitted to flow to the return chamber H0 through the conduit |33 and the normally open 4port 330 ci the pilot valve. The levers 244, 246, vand 3|2 of thecontrol apparatus are also in their normal positions, that is, the horizontal positions in which they are indicated in Figs. 9 and 10. Incase it is desired to raise the elevator at high'sp'eed, the handle 64 of the car switch is moved counterclockwise to energize the solenoid 55' through'a` circuit that has been previously 'described and which, it may be remembered, extends through' the upper limit switch 34. The 'solenoid winding immediately moves downward- Llyits plunger 248 and associated link 25B with the result thelever 244 is rotated counterclockwise '(as viewed in Fig. 10) through an angle determined by the adjustment of adjusting screw 262. rlhe lever 244 tensions thesprings'268 and 214, the former of which thus exerts a biasing force Itending to return the lever 244 to its normal position, and the latter of which exerts a turning force on the lever 246 tending to turn the latter .in the same direction as the lever 244, that is, in -a counterclockwise direction. The spring 23e turns the lever 24S at a uniform rate which is determined by the adjustment of valves 254 of vthe dash pots 282, which, it may be remembered, are operatively connected to the lever 24S through links 288.

As soon as lever 245 rotates, the switch 62 is closed as the cam member 332 permits the resilient switch actuating member 394 to move outwardly to remove the pressure from the switch operating button 306. When switch 62 closes, a circuit is completed for the motor switch operating solenoid 52, with the result that the pump motor circuit is closed and the pump is started, As soon as the pump starts, oil flows from the discharge side of the pump into the valve passagewayv 98 through conduit 24. The oil at this time, however, is bypassed tothe reservoir inasmuch as the bypass valve is open, the oil flowing from passageway 92 to the reservoir through the port H8, the passageways |23, the return chamber ll, and conduit 22. As a result, the motor and pump accelerate quickly and at but a very light load to full speed.

The pressure in chamber 98 is gradually built up by the closure of the bypass valve. There is an initial slight loss of pressure between port H8 and return chamber il when oil flows through passageway |33 in the bypass valve piston |22 into the pressure chamber |34. This liquid is initially iree to flow to the return chamber Elli through the conduit |38 and the normally open port 33t of the pilot valve.

It has already been indicated that the lever 246 gradually rotates in a counterclockwise direction. As it does so, the lever arm 292 gradually depresses the left end (as viewed in Figs. 9 and 10) of the pilot valve controlling floating lever 296. As this end Vis depressed, the pilot valve piston 36| is moved downwardly, gradually to cut off the ow of oil from the pressure chamber |34. Consequently, the pressure in this chamber is increased to equal that in the passage way 32 and portll. The effective area of the left side of the piston |22 (the area open to the pressure chamber) is greater than that of the right side of the piston (the area open to pressure in passageway S2), so that when the pressures in the latter and in the pressure chamber are equal, the entire piston assembly moves to the right compressing the relatively light spring |32 and further restricting the flow 'of oil past the bypass valve into the return chamber H0. The pressure in the passageway 98 thus increases and the bypass valve ||2 is moved in closing direction until the pressure in passageway 98 eX- ceeds that in chamber |62, which pressure is created by the hydrostatic head of oil in the elevator system and the weight of the elevator car and associated parts. When this occurs, the check valve |00 opens and a portion of the oil flows past the vane |4, rotating it in a counterclockwise direction, and the'elevator is started in upward direction at a slow rate. v

The speed vane |04 consequently rotates the lever 3|2 in a counterclockwise direction, and the latter lifts the righthand end of the floating lever 293 through the connecting link 3|6. This upward movement of the floating lever tends to counteract the effect of movement oi lever 24B by the spring 214, that is, it has a tendency to prevent closure of the port 330 by the movable pilot valve piston 30|.

If the speed of the elevator is increased to too great a rate, the speed vane will be displaced so far that the righthand end of the iloating lever will be lifted enough to reopen the port 33t, thereby bleeding away all the liquid entering the bypass Valve pressure chamber |34 and causing the bypass valve partially to reopen.

As the bypass valve is progressively closed un- Y der the conjoint control of the levers 246 and 3I2, liquid flows past the vane |94 so that the latter is no longer capable of movement, and finally the lever 246 moves the pilot valve piston 30| down "-13 completely to close port 3130 of the bypass valve. 'Thus theelevator :moves upwardly at its maXimum speed and the `various parts of the system remain Ain this position during the upward travel Vof :the elevator at its high speed.

If during the period 'when the bypass valve is being closed the speed of the elevator is less than it should be, the speed vane returns towards its normal position, that is, it moves in clockwise direction. This movement depresses the rightend of the o'ating lever so that both the lever -2lit and the'speed vane lever 3|2 tend to move the pilot valve member downwardly to close the vport 330. This has a tendency to increase the flow of liquid to the elevator and to increase the speed of the latter to the desired value.

`lil/"hen the elevator approaches the landingat ywhich it is desired to stop, either the upper limit .switch .34 .or thecar switch is operated to .interrupt the circuit to .the solenoid When the :solenoid is .deenergized its plunger is released and Ithe springs vZt andf214 return the levers 245i and `2:16 to their normal horizontal positions, the Vspring .268 I.acting on lever 244 and the latter in iturn acting .onlever 246 through spring 2'14. The lmovement of lever 246, however, is at a gradual .and uniform lrate by reason of the control action of 'the dash lpots '282.

As the lever 245 rotates in a clockwise direction, yit-fraises the left end of the floating lever, thereby partly opening port 330 to reduce the pressure in the pressure chamber 13:1 of the bypass valve so that the bypass valve commences to open. As foil begins to flow through the bypass valve, the `flow past the speed vane lllll is reduced 'and it is .urged in-a clockwise direction by spring 22E. This movement .lowers the right end of the .oating lever with the result that the pilot valve piston .30| is moved in a-direction to close the port 33B. Thepilotvalve is .thus constrained to take an intermediate position so that the bypass valve opens .at a uniform rate, thereby to decelerate the ele- -vater at a uniform rate.

When the elevator stops, the check valve Hit I.closes rb y gravity to prevent reverse flow. The bypass valve, however, continues to open until it strikes the closure cap I'ZE, or a stop ring which ,may `be inserted between'the closure cap and the valvebody to limit its movement for the purpose of preventing the bypass from opening so 'far that insufficient pressure diierence will exist between passageway 92 and return chamber Il@ -to initiate lclosing movement of the piston valve when :liquid fis :prevented from iiowing from the pres- -sure chamber |34.

'The lever `21H5 vcontinues to rotate in a clockw'isedirection untilit reaches its normal position, .at whichtime the switch B2 'is opened `'to deenergize the motor controlling solenoid '52 and the v-pi'lot valve Vpiston 3| is returned to its norrnal position to open port 338, the port 338 remaining `closed.

For eX-treme accuracy in effecting landings or to `raise the elevator a short distance only, -it is desirable yto raise vthe elevator at a low speed. This canbe accomplished by energizing the solenoid 54, the vassociated adjusting screw 262 of which is adjusted-so that full stroke of the associated plunger 248 will rotate the lever 244 through a lesser angle than that through which the lever is rotated lupon energiza'tion of solenoid "-56. Iff the elevator be assumed to sta-rt from rest, the operation is the same as that described above 'with exception that 4lever 24S is rotated a 'lesser angle 'corresponding to the Alesser angle of lif) the pressure chamber |3fl and thereby reducing the pressure behind the piston |22.

The flow -oi liquid to the elevator is thus maintained ata reduced volume, the balance of the oil pumped being returned tc the reservoir through the bypass valve.

If vfor a-ny reasonthe resistance encountered by the elevator should increase, as for instance by a decreased hydrostatic head acting on the bottom oi the plunger as it rises, the ilow through the bypass valve will increase and that to the elevator will decrease accordingly. Should this occur, the speed vane drops partially to its center position, moving the pilot valve piston 3i!! to close the port 339 suiciently vte reestablish the desired rate or now to -the elevator.

When it is desired to reduce the speed of the elevator from full speed tolow speed, the solenoid 56 isdeenergized and solenoid 54 energized. YThis reduces the angular displacement of the lever ii with the result that lever 248 moves gradually into alignment with lever 24e. During this movement, the port 33% will be opened somewhat to epen the bypass valve the desired amount. When the speed or the elevator i-s reduced to the value for which the controls are adjusted, the pilot valve member 3S! is brought back by the vane `to an intermediate position at which the port 330 lis opened sufliciently to maintain the desired low speed.

When it is desired to stop the elevator during its travel at low speed, itis necessary only to deenergize the solenoid 54, in which event the elevator is stopped in the same manner as described above in connection with stopping the elevator during its travel at high speed.

It should be understood that there is a position or the pilot Valve piston Sill in which the port 33! is partly closed so that the pressure in the bypass pressure chamber i3d bears the same ratio to the pressure in passage 92 .as the area of `the face of the bypass valve piston exposed to pressure in the passage 92 bears to the area of a lefthand side of the piston (neglecting the small force exerted by the right spring |32) In this Aposition of the pilot valve piston, the bypass valve will neither open nor close. Any slight deviation of the pilot valve piston from this position will cause slow motion of the bypass Valve in the opening or closing direction, as the case may be, Iwhilea considerable pilot valve motion will produce a correspondingly rapid motion of the bypass valve.

It should also be understood that for each rate of oil now vpast the speed vane Hifi, to or from the elevator, there is a corresponding angular position of the vane, as it is acted upon only by the now of oil and its motion is resisted by the spring l22%. Since, for stable operation at constant pressure, the position of the pilot valve piston 363i is determined, it may be seen that each angular position of the vane has a corresponding position of the floating lever 296. If the lever is caused to assume any such position and adequate hydraulic liquid supply is provided, a corresponding speed will be maintained.

In other words the low speed operation of the valve is wholly dep-endent on the vane 64. Were that end of the lever 2%, to which the vane is attached, regarded as a stationary pivot, the movement of the other end of the lever would l5 result only in a more or less rapid closing of valve ||4 but in any case a closing to the fully closed position. The actuation of solenoid 54 has the eiect of placing the pilot valve Sil! with resp-ect to port 33e in such a position that the pressure relief through the pilot valve is slightly less than the pressure intake through passage |36. The end of lever 296 associated with solenoid 54, which solenoid produces this pressure diierential, may after actuation of the Solenoid be regarded as a fixed fulcrum. Thereafter as the iluid flow past the vane accelerates, the vane moves to counter the' solenoid placement of the pilot valve 38|. This Yhas the eiect ofv gradually equating the pressures on each side of valve I I4 as the valve moves toward the closed position or creating a situation with respect thereto at some point in the course of valve H4 travel where the pressure relier" is equal to the pressure intake through passage |36. At this point the valve movement lwill necessarily stop because of this lack oi pressure differential, so producing the reduced iiow rate desired.

For the sake of efficiency, the bypass should be entirely closed during full speed travel of the elevator. To insure this closing, the adjusting screw 262 associated with solenoid 56 is so adjusted as to produce rotation of levers 241| and 256 beyond the position corresponding to the full speed of which the pump is capable; this additional rotation of the levers depresses the pilot valve member 38| beyond the position for balancing the bypass valve and consequently the latter is fully closed.

To lower the elevator, it is necessary to energize either solenoid 58 or 6E depending upon whether slow or high speed is desired. The action is similar to that in raising the elevator except that the lowering valve |88 is normally closed as the pilot valve port 333 is normally closed by the piston 33| of the pilot valve. The lowering of the elevator is effected by gravity Iand when either of solenoids 53 or 6i! is energized, the switch 62 remains open by reason of the configuration of the cam 332 formed as a part of lever 21M, this conguration being such that when the levers 245 and 246 are moved clockwise by energization of solenoids 58 or 5d the switch remains open.

Assuming rst that it is desired to lower the elevator at high speed, then the solenoid SG is energized. The plunger 2513 of this solenoid effects movement of lever 2413 in a clockwise direction, ywith the result that the lever 24S is slowly and at a uniform rate moved in the same direction. The solenoid andspeed vane again exert opposing eects on the floating lever 295, the solenoid tending to open the port 338, and the speed vane tending to close the port in the event that lowering speed is too great. The extreme angular travel of the vane is designed to be greater than that produced by the highest desired lowering speed, while the maximum angular travel of lever 2M is restricted to produce a lesser movement of the pilot valve member 30|. Consequently, the speed is governed up to the highest possible setting of the adjusting screws 262. Y

it .should be noted that the lowering speed is limited byithe size of the opening of the lowering valve port l'iand the minimum working pressure of the elevator. The only time that the valve fails to maintain a constant lowering speed is when the above limiting conditions are reached with minimum load and maximum speed adjustment.

Should the pressure within passage 92 or in the system rise to some value above a desired maxiating pressure in vpassageway 98, P that in-they pressure chamber, and I be the force exerted by spring |32. It is apparent when the valve is in equilibrium PA-l-I In other words, the pressure is lower` in the pressure chamber than in passageway 93 by the ratio ofthe area of the valve face to the pistonV face, except for theV relatively small correction for spring |32. When, as during full speed upward travel of the elevator, the pilot Valve entirely cuts off the iiow of liquid from the pressure chamber, otherY means must be provided to preventthe pressure in this chamber from rising above the setting of the overpressure relief spring 46 unless the pressure P is actually above the limit desired to be maintained. To accomplish this purpose, the discharge port |48 is so shaped at its opening into piston chamber' |44 that a very small opening will be uncovered by initial motion of piston |42. This end is attained by providing the tapered groove |58 at the end of passageway Hi8. As the piston moves initially, a small portion of this groove is uncovered and as the piston moves further, the area of the exit passage finally exceeds that of the passage |36. The escape of fluid from pressure chamber |34 thus provided will prevent further rise in pressure in the pressure chamber as long as this rise is due only to entrance of liquid through passageway |36.

However, if the pressure in passageway 98'v exceeds the predetermined pressure P, that in chamber |34 will exceed P with the result that the piston |42 will move further to the right (as viewed in Fig. 5), thus uncovering enough of the port |48 to exhaust oil from the pressure cham-ber faster than it can enter through the passageway |36. As a result, the bypass valve piston |22 will move to the left and open the bypass ports |20 the necessary extent to limit the pressure in chamber 98 to the desired value. l It may be noted that the passages |48 may be relatively large so as to permit very rapid evacuation of liquid from pressure chamber |34 and a very rapid full opening of the bypass valve. This constructionprovides against destructive pressure rise in the event of sudden obstruction of ilow of liquid to the elevator.

When the bypass valve has been opened as a result of excessive pressure, it will move to and remain at a position that will maintain the desired pressure in passageway 98, since it is designed to pass the entire output ofthe pump with which it is used at a pressure much less than the desired pressure at which the relief is had. During bypassing because of overpressure, the relationship between the pressures and areas set forth above holds, and fails to hold only when the bypass valve is bearingagainst one of the stops which limits its travel.

Any external change resulting ina decrease in pressure in the passageway 98 results in a decrease in pressure in chamber |34 with the result that the relief valve piston |42 moves back to cut off the flow of liquid through the passageway Hi8 and with the further resultJ that the bypass valve is closed.

While the above illustrative embodiment of the invention has included a pump and motor as the source of fluid under pressure, it should be noted that it is possible to use other sources and retain advantages accruing from the use of the valves. For instance, the source may well be of any type providing a substantially constant volumetric ow-and certain of the advantages of the invention are retained when the source is of the variable flow type. Likewise, the invention is applicable to systems other than hydraulically actuated elevators. It is also applicable to automatically controlled systems because of the ease with which the valve may be controlled.

What I claim as new and desire to secure by United States Letters Patent is:

1. In a pilot operated valve mechanism comprising a valve casing having an inlet passage communicating with a high pressure region and an exhaust passage communicating with a low pressure region, a main valve between said inlet passage and exhaust passage and an actuating' piston connected thereto, and the casing and the back side of the piston defining a pressure chamber, the combination including, a small passage providing communication between the inlet passage and said pressure chamber, means including a pilot valve providing communication between said pressure chamber and the exhaust passage for relieving the pressure in said chamber, means including a lever operatively connected to said pilot valve to move the latter to relieve the pressure in said chamber to open said valve, means including a second lever resiliently connected to said mst-mentioned lever for moving the latter, and means including movement restraining means operatively connected to said first-mentioned lever for controlling the rate of movement of said pilot valve.

2. In a pilot operated valve mechanism comprising a valve casing having a fluid flow passage leading from an inlet under pressure to an eX- haust at a lower pressure, an interconnected valve and an actuating piston therefor for controlling the now of fluid through said passage, said valve separating said passage into an upstream high pressure side and a d-ownstream low pressure side the casing and the back side of the piston dening a pressure chamber, the combination including, a small passage providing communication between the high pressure side of said valve and said pressure chamber, means including a pilot valve providing communication between said pressure chamber and the low pressure side of said valve for relieving the pressure in said chamber, means for operating said pilot valve to relieve the pressure in said chamber, said means including a oating lever connected between its ends to said pilot valve and a movable lever connected to one end of said floating lever, and means including means forming an inlet passage leading from the high pressure region of said fluid flow passage to a fluid supply, a vane in said inlet passage movable in response to the rate of iluid flow through the last said passage and connected to the other end of said floating lever for controlling the operation of the pilot valve in response to the rate of flow of fluid in said inlet passage.

3. In a pilot operated valve mechanism comprising a valve casing having a fluid relief passage, an interconnected valve andan actuating piston therefor for controlling the flow of fluid through said relief passage, the casing and back side of the piston defining a pressure chamber, the combination including, a small passage providing communication between the iront of the piston and the pressure chamber, means including a pilot valve providing communication between the pressure chamber and a low pressure region for relieving the pressure in said chamber, means for operating said pilot valve to control the relief of pressure in the chamber, means forming a uid flow passage, and means including a member in the iiuid iiow passage responsive to the rate of fluid now therethrough for modifying the pilot valve operating means in response to the rate of iiuicl iiow through said fluid flow passage.

4. A pilot valve mechanism for controlling a iiuid flow regulating valve, including in combination, a movable pilot valve member, a floating lever connected intermediate its ends to said valve member, a rotatable lever operatively connected to one end of said floating lever, means for rotating said lever in opposite directions to move said valve member, and a lever rotatable into different positions and in diierent directions in response to the rate and direction of fluid flow and operatively connected to the other end of said floating lever for controlling the position of the pilot valve member.

5. A pilot valve mechanism for controlling a iluid ow regulating valve, including in combination, a movable pilot valve member, a pair of valve ports associated therewith, said valve member normally closing one and normally opening the other of said ports, a floating lever connected intermediate its ends to said valve member, a rotatable lever operatively connected to one end of said oating lever, means biasing said lever to a normal position corresponding to the normal position of said valve member, means for rotating said lever in opposite directions to move said valve member relative to said ports, a second lever rotatable into different positions and in opposite directions in response to the rate and direction of fluid flow and operatively connected to the other end of said floating lever for controlling the position or" the pilot valve member, and means for biasing said second lever into a predetermined position occupied thereby when no fluid is iiowing.

6. In a pilot operated valve mechanism comprising a valve casing having an inlet passage communicating with a high pressure region and an exhaust passage communicating with a low pressure region, an interconnected valve and an actuating piston therefor, a spring for biasing the valve normally to close communication between said passages, and the casing and the back of the piston defining a pressure chamber, the combination including, a small passage providing communication from a region between the piston and valve in the inlet passage to said pressure chamber, means including a normally closed pilot valve providing communication between said pressure chamber and the low pressure region i`or relieving the pressure in said chamber to eiect opening of the valve, operating means for opening said pilot valve to relieve the pressure in said chamber, movement restraining means associated with said operating means toxefect opening movement of the pilot valve at a" uniform ratey means forming a branch passage leading from said inlet passage, and means controlling said pilot valve in response to the rate of flow of fluid through said branch passage and tending 19 to close said pilot valve in the event the pilot valve is opened too rapidly and the iiow of fluid in the branch passage increases too rapidly.

7. In a pilot operated valve. mechanism comprising a valve casing having an inlet passage communicating with a high pressure region and an outlet passage communicating with a low pressure region, an interconnected normally open valve and an actuating piston therefor, the valve normally providing communication between said passages and the casing and the back of the piston dening a pressure chamber, the combination including, a small passage providing communication from a region between the piston and valve in the inlet passage to said pressure chamber, means including a normally open pilot valve providing communication between said pressure chamber and the low pressure region for relieving the pressure in said chamber, and

movable to increase the pressure in said chamber I to effect closure of the valve, means for moving said pilot valve, restraining means controlling said moving means to effect movement of the pilot valve at a uniform rate, means forming a branch passage leading from said inlet passage,

and means controlling said pilot valve in response to the rate of flow of fluid through said branch passage for preventing too rapid movement of the pilot valve and change in rate of iiuid ow.

8. In a pilot operated valve mechanism cornprising a valve casing having an inletI passage communicating with a high pressure region and an outlet passage communicating with a low pressure region, an interconnected normally open valve and an actuating piston therefor, a spring for biasing the valve normally to provide communication between said passages, and the casing and the back of the piston defining a pressure chamber, the combination including, a small passage providing communication from a region between the piston and valve in the inlet passage to said pressure chamber, means including a normally open pilot valve providing communication between said pressure chamber and the low pressure region for relieving the pressure in said chamber and movable to increase the pressure in said chamber to eiiect closing of the valve, operating means for closing said pilot valve to build up the pressure in said chamber to close said valve and for opening said pilot valve to relieve the pressure in said chamber to open said valve, movement restraining means associated with said operating means to effect closing and opening movements of the pilot valve at a uniform rate, means forming a branch passage leading from said inlet passage, and means controlling said pilot valve in response to the rate of flow of fluid through said branch passage and tending to open said pilot valve in the event the pilot valve is closed too rapidly and the flow of fluid in the branch passage increases too rapidly and tending to close said pilot valve in the event the pilot valve is opened too rapidly and the Iiow of fluid in the branch passage decreases too rapidly.

9. A start-cushioning valve for use with a source of fluid under pressure and a device to be actuated by the fluid, including in combination, a uid inlet passage, a uid bypassage, a valve member between said passages having a portion thereof open to said'uid passage, a spring biasing said valve member to an open position wherein said passages are in communication, and means for gradually closing said valve when uid under pressure is admitted to said Iiuid inlet pas- 2i) sage, lsaid last mentioned means including 'a piston operatively connected to said-valve member and having an area greater than said portion of the valve member, a cylinder in which said piston is movable, the cylinder and back side -'of the piston defining a pressure chamber, anda small passage interconnecting said uid inlet passage and pressure chamber. 10. A hydraulic system, including in combina tion, an electric motor, a positive displacement pump having an outlet and driven by said motor, a conduit connected to the pump outlet, a uid bypassage, a valve member between said conduit and bypassage having a portion thereof open to said conduit, a spring biasing said valve member to an open position wherein said conduit'and bypassage are in communication, means for energizing said motor, and means for gradually closing said valve when said motor is energized whereby said motor is enabled to acceleratelt'o full speed at low pressure, said last-mentioned means including a piston operatively connected to said valve member and having an area greater than said portion of the valve member, a cylinder in which said piston is movable, the cylinder and back side of the piston dening a pressure chamber, a small passage interconnecting said fluid passage and pressure chamber, a normally open pilot valve for controlling the relief of pressure in said chamber, lmovable pilot valve operating means, and means delaying operation of said operating means, said operating means being effective upon initial movement to operate said motor energizing means.

ll. A hydraulic system, including in combination, an electric motor, a positivey displacement pump having an outlet and driven by said motor, a conduit connected to the pump outlet,l a fluid bypassage, a valve member between said conduit and bypassage having a portion thereof open to said conduit, a spring biasing said valve member to an open position wherein said conduit and bypassage are in communication, means for controlling the energization of said motor, and means i'or gradually opening said valve and thereafter deenergizing said motor, said lastrnentioned means including a piston operatively connected to said valve member and having an area greater than said portion of the valve member, a cylinder in which said piston is movable, the cylinder and back side of the piston dening a pressure chamber, a small passage interconnecting said iiuid passage and pressure chamber, a normally open pilot valve for controlling the pressure in said chamber operablev to restrict low of fluid from the pressure chamber when the motor is energized, movable pilot valve operating means for opening said pilot valve, and means delaying operation Vof said operating means, said operating means being effective after movement of said pilot valve to its open position to deenergize said motor.

12. A hydraulic system, including in combination, an electric motor, a positive displacement pump having an outlet and driven by said motor, a conduit connected to the pump outlet,"a fluid bypassage, a valve member between said' conduit and bypassage having a portion thereof open vto said conduit, a spring biasing said valve member to an open position wherein said conduit and bypassage are in communication, means for controlling the energization of said motor; means for gradually closing said valve when said motor is energized wherebysaid motor is enabled to accelerate to full speedat low pressure, said last- 21 mentioned means including a piston operatively connected to said valve member and having an area greater than said portion of the valve member, a cylinder in which said piston is movable, the cylinder and back side of the piston defining a pressure chamber, a small passage interconnecting said fluid passage and pressure chamber, a normally open pilot valve for controlling the relief of pressure in said pressure chamber, movable pilot valve operating means, and means restraining operation of said operating means, said operating means being effective upon initial movement to operate said motor energization controlling means, and means for gradually opening said Valve and then deenergizing said motor, said means including the pilot valve, the pilot valve operating means and the restraining means.

13. A hydraulic system, including in combination, an electric motor, ay positive displacement pump having an outlet and driven by the motor, a pilot operated valve mechanism comprising a valve casing havingan inlet passage connected to said outlet, a combined outlet and return passage, and an exhaust passage, a check valve between the inlet and the outlet and return passages preventing return flow from the latter to the former passage, a valve biased to closed position located between the exhaust and outlet and return passages and having a piston connected thereto, the back side of said piston and the casing defining a pressure chamber, a valve biased to open position between the inlet and exhaust passages and having a piston connected thereto, the back side of said piston and the casing defining a second pressure chamber, a small passage providing communication between the outlet and return and the first pressure chamber, a second small passage providing communication between the inlet passage and the second pressure chamber, means including a pilot valve and a pair of spaced ports controlled thereby for controlling the relief of pressures in said chambers, said pilot valve occupying a normal position wherein said first small passage is closed and the second open, means for selectively moving said pilot valve selectively to open said first small passage and to close the second, thereby to effect selective opening of said normally closed valve and closing of the normally open valve, said means including a fioating lever connected intermediate its ends to said pilot valve, a first rotatable lever connected to one end of said floating lever, a second rotatable lever resiliently connected to the first and biased to a predetermined position, a first pair of solenoids selectively energizable to rotate said second and first leversin one direction to move said pilot valve into different closing positions relative to said second small passage, and a second pair of solenoids selectively e-nergizable to rotate said second and first levers in the opposite direction to move said pilot valve into different opening positions relative to said rst small passage, a pair of dashpots secured to said first lever to cause it to move at a uniform rate, whereby said pilot valve is moved. at a uniform rate, means for controlling said pilot valve in response to the rate of iiuid flow through said combined outlet and return passage, said last-mentioned means including a pivotally movable vane in said passage, resilient means biasing it to a central normal position, and a lever connecting the vane to the other end of said floating lever, and motor controlling switch means operable by said first rotatable lever, said switch means being operable to energize said motor upon initial rotation of said first lever in said opposite direction by energization of either of said rst pair of solenoids and to deenergize said motor upon final return rotation of said lever when said solenoids are deenergized.

14. In apparatus of the class described, the combination including, a fluid flow regulating valve, and means responsive to the rate of fiuid flow for controlling the position of said valve, said last mentioned means including a vane movable in opposite directions in response to the direction of fluid flow and to an extent determined by the fluid velocity and means controlled by said vane for continuously varying the position of said regulating valve thereby to vary continuously the rate of iow through said valve in proportion to the movement of the vane.

15. In apparatus ofthe class described, the combination including, a fluid dow regulating Valve, and means responsive to the rate or fluid ow for controlling the position of said valve, said last mentioned means including a semicylindrical housing having a port in each of the two opposite quadrants of its cylindrical surface, a vane closely fitting and swingably mounted in said housing, and means biasing said vane to a mid position wherein it obstructs the passage between the ports and from which it is movable in response to pressure from either port in proportion to the rate of fluid iiow.

16. Fluid iiow regulating apparatus comprising a normally open by-pass valve adapted to bypass fluid owing in a conduit, means including a piston connected to said valve and to which is applied the pressure difference across the seat of said by-pass valve for gradually closing said by-pass valve, and means responsive to the rate of fluid iow in said. conduit for controlling the movement of said piston and thereby of said by-pass valve in response to the rate of flow of fluid.

i7. Fluid flow regulating apparatus as claimed in claim 16 including electromagnetic deans ccntrolling said by-pass valve closing means for rendering said means operable to close said valve.

18. Fluid now regulating apparatus comprising a normally open by-pass valve adapted to bypass fluid novving in a conduit, means including a piston connected to said by-pass valve and a pilot valve controlling the pressure applied to said piston for controlling theposition of said by-pass valve, and means including a movable vane biased to a position to obstruct flow through the conduit and movable to an extent proportional to the rate of fluid fiow through the conduit for controlling the pilot valve to vary the pressure applied to the piston to effect opening movement of said by-pass valve when flow past the Vane is above a predetermined value to effect closing movement of said by-pass valve when the flow is less than said value.

i9. Fluid flow regulating apparatus comprising a by-pass valve controlling the nov.' of fluid through a conduit, means including a piston connected to said valve and a pilot valve controlling the pressure applied to said piston for controlling the position of said by-pass valve, and means including movable vane biased to a position to obstruct dow through the conduit and movable to an extent proportional to the rate of fiuid now through the conduit for controlling the pilot valve to vary the pressure applied to the piston to eeot closing movement of said valve when the flow past said vane is above a predetermined 23 value and to effect opening movement of said valve when the iiow is less than said value.

20. In combination with a valve mechanism including a valve casing having a fluid new passage and a main valve in said passage dividing said passage into an upstream high pressure side and a downstream low pressure side; a pilot valve mechanism governing the main valve to control the rate of acceleration of fluid flow in the passage comprising a piston connected to said main valve, the back side of the piston and a portion of the casing being formed to define a pressure chamber, a small passage providing communication between the high pressure side of said valve and the pressure chamber to urge closure of the valve, a pressure relief passage providing communication between the pressure chamber and the low pressure side of said valve, a pilot valve in the pressure relief passage, and means operative to effect different degrees of opening of said pilot valve, relieving the pressure in said pressure chamber at different rates, so effecting different rates of movement of said main valve.

21. In combination with a valve mechanism including a valve casing having a fluid flow passage and a main valve in said passage dividing said passage into an upstream high pressure side and a downstream low pressure side; a pilot valve mechanism governing the main valve to control the fiuid flow in the passage comprising a piston connected to said main valve, the back side of the piston and a portion of the casing being form-od to define a pressure chamber, a small passage providing communication between the high pressure side of said valve and the pressure chamber to urge closure of the valve, a pressure relief passage providing communication between the pressure chamber and the low pressure side of said valve, a pilot valve in the pressure relief passage, means including a lever operatively connected to said pilot valve to move the pilot valve to relieve the pressure in said chamber, and means including a second lever resiliently connected to said first lever for moving the latter.

22. The combination claimed in claim 2l wherein movement restraining means are operatively connected to the first mentioned lever for controlling the rate of movement of said pilot valve.

23. In a pilot operated valve mechanism comprising a valve casing having a fluid flow passage, a main valve and an actuating piston for said valve connected thereto for controlling the flow of fluid through said passage, said valve separating said passage into an upstream high pressure side and a downstream low pressure side, the casing and back side of the piston defining a pressure chamber, the combination including a small passage providing communication between the high pressure side of said main valve and said pressure chamber, means including a pilot valve providing communication between said pressure chamber and the low pressure side of said main valve for relieving the pressure in said chamber, a oating lever connected between its ends to said pilot valve for operating said pilot valve to relieve the pressure in said chamber, manually controlled means operative to move one end of said lever, means forming a branch passage leading from said upstream high pressure side and a vane in said branch passage movable in response to the rate of fluid flow through. the branch passage and connected to the other end Of said floating lever for controlling the operation 24 of the pilot valve in response to the rate of flow of fluid in said branch passage.

24. A pilot valve operated mechanism comprising a valve casing having a fluid now passage, a main valve in said passage dividing said passage into an upstream high pressure side and a downstream lou7 pressure side, a piston connected to said valve, the back side of the piston and a portion of the casing being formed to define a pressure chamber, a small passage providing communication between the high pressure side of said valve and the pressure chamber to urge closure of the valve, a pressure relief passage providing communication between the pressure chamber and the low pressure side of said valve, a valve in the pressure relief passage, manually actuated means for operating the pilot valve to control the relief of pressure Yin the pressure chamber, means forming a branch passage leading from said upstream high pressure side, and means actuated by ow of fluid through the branch passage connected to the means for operating the pilot valve to vary the operation of the manually actuated means upon the pilot valve.

25. In combination with a main valve mechanisrn including a fluid flow passage, a valve in said passage, means defining a pressure chamber operatively associated with said valve to control the positioning of said valve and means for admitting fluid under pressure to said pressure chamber, a pilot valve mechanism for controlling the degree of opening of said main valve comprising a pilot valve having a port connected to effect the relief of pressure in the pressure chamber and a movable member to close variably said port, manually controllable means connected to the movable member to cause an initial positioning of the member with respect to the port, means forming a branch passage connected to the rst said passage upstream of said valve, and a vane responsive to the flow of fiuid in said branch passage connected to said movable member in opposition to the manually controllable means to modify the position imposed on sai member by said manually controllable means to alter the rate of pressure relief of said pressure chamber, thereby to check the movement of the main valve.

26. In combination with a main valve mechanism including a fluid flow passage, a valve in said passage, means defining a pressure chamber operatively associated with said valve to control the position of said valve and means for admitting fluid under pressure to said pressure chamber; a pilot valve mechanism for controlling the degree of opening of said main valve comprising a pilot valve having a port connected to effect the relief of pressure in the pressure chamber and a movable member to close variably said port, manually controllable means connected to the movable member to cause an initial positioning of the member with respect to the port to move said main valve, means forming a branch passage connected to said fluid iiow passage upstream of said valve, and means responsive to the now of fiuid in said branch passage connected to said movable member in opposition to the manually controllable means to modify the position imposed by said manually controllable means to alter the rate of pressure relief of said pressure chamber, thereby to check the movement of said main valve.

27. In combination with a main valve mechanism including a fluid flow passage, a valve in said passage, means defining a pressure chamber operatively associated with said valve to control the positioning of said valve and means for admitting fluid under pressure to said pressure chamber; a pilot valve mechanism for controlling the degree of opening of said main valve comprising a pilot valve having a port connected to effect the relief of pressure in the pressure chamber and a movable member to close variably said port, a iioating lever connected intermediate its ends to the movable member, manually controllable means connected to one end of said lever to cause an initial positioning of the member with respect to the port to move said main valve, means forming a branch passage connected to the rst said passage upstream of said valve, and means responsive to the ow of fluid in said branch passage connected to the other end of said lever to counteract said manually imposed positioning of said member to alter the rate of lpressure relief of said pressure chamber, thereby to check the movement of said main valve.

28. A pilot valve operated mechanism for providing a constant iluid flow rate in a conduit comprising a valve casing having a fluid loW passage adapted for insertion in said conduit, a main valve in said passage dividing said passage into an upstream high pressure side and a downstream lovv pressure side, a piston connected to said valve, means movably containing the piston, and, with the piston, forming a pressure chamber, a small passage providing communication between the high pressure side of said valve and the pressure chamber to urge the valve counter to the direction of urging of the pressure in said passage, a pressure relief passage providing communication between the pressure chamber and the 10W pressure side of said valve, a pilot valve in the pressure relief passage having a port for the relief of pressure in the pressure chamber and a movable member to eiect a continuously variable closure of said port, manually controllable means for moving said movable member to a iiXed position with respect to said port to adjust the opposing forces on said main valve to produce movement thereof, means forming a branch passage connected to the first said pas# sage upstream of said valve, and means responsive to the flow rate in said branch passage connected to said movable member in opposition to said manually controllable means to modify the positioning of said movable member to balance the forces on each side of said valve.

29. A pilot valve mechanism for controlling a fluid pressure component for a fluid flow regulating main valve mechanism, said main valve mechanism including a fluid flow passage and a main valve in said passage movable in response to the difference in forces exerted in opposite directions thereon, one of said forces including a fluid pressure component comprising a pilot valve having a port therein adapted for fluid connection, and a movable member adapted to close variably said port, manually controllable means connected to the movable member to cause an initial positioning of the member with respect to the port to produce an unbalance of said forces to move the main valve, means forming a branch passage connected to the rst said passage upstream of said valve, and means connected to said movable member responsive to the W of fluid in said branch passage in opposition to the manually controllable means to modify the position imposed on said member by said manually controllable means to rebalance said forces to check the movement of the main valve.

LAWRENCE F. JASEPH.

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

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