US2495785A

US2495785A - Lowering valve

Info

Publication number: US2495785A
Application number: US572387A
Authority: US
Inventors: William T Stephens
Original assignee: HYDRAULIC EQUIPMENT Co
Current assignee: HYDRAULIC EQUIPMENT Co
Priority date: 1945-01-11
Filing date: 1945-01-11
Publication date: 1950-01-31
Anticipated expiration: 1967-01-31

Description

Jan. 31', 195o Filed Jan. 11, 1945 Fig-1 FLOW CONT. VBI-V E.

w. r STEPHENS Lomme VALVE 2 Sheets-Sheet 1 RESERVOlR Swan/rm WILLIAM T. STEPHENS Jan. 31, 1950 w, T, STEPHENS 2,495,785

LOWERING VALVE Filed Jan. 11, 1945 2 Sheets-Sheet 2 215C?. Q. .,25. "I5 73 72 'Zl L" :RESERVOIR Fpow coN'L 2 O VALVE 5.. CONT VALVE "'4 PUMP 3mm WILLIAM fr. sTPHNs m f@ Mensys Patented Jan.v 31, 1950 LOWERING VALVE William T. Stephens, Cleveland, Ohio, assignor,

by mesne assignments,

to Hydraulic Equipment Company, Cleveland, Ohio, a corporation of Ohio Application January 1l, 1945, Serial No. 572,387

7 Claims.

This invention relates to flow regulating devices and more particularly to devices for automatically maintaining a relatively constant rate of liquid flow irrespective of pressure. In a specinc embodiment the apparatus is intended for providing relatively uniform lowering of a hydraulic hoist or like devices which rate is independent of the load on the hoist.

It is a general object of the present invention to provide a novel and improved vilow regulator for liquids.

More particularly it is an object of the present invention to provide a'flow regulator to be inserted between a. hydraulic hoist and the control valve for operating the same and which is are rangedto control the return of liquid from the hoist to the valve at a relatively uniform rate independent of the load on the hoist and consequently.the pressure of the returning liquid.

An important feature of the invention comprises the serial arrangement of a xed and a variable flow restricter, the former providing the changes in pressure for theoperation of the latter.

Another important feature of the invention consists in the arrangement of a device of the character described to include a passage extending between a port connected to the hoist and a port connected to the operating valve which passage is equipped with a semi-fixed oriilce type restricter and an automatic adjustable restricter, the latter comprising a plunger operative in the portion of the path and having a head exposed to the pressure between the two restricters for the automatic operation of the plunger.

A further feature of the invention and illustrated in two embodiments thereof comprises the arrangement of a parallel path between said ports including a check valve permitting maximum flow from the control valve to the hoist but preventing return flow except through the controlled path.

Otherand further features and objects of the invention will be more apparent to those skilled in the art upon a consideration of the accom- 'panying drawings and following specification wherein are disclosed exemplary embodiments of the invention with the understanding that such changes, modiiications and combinations thereof may be made as fall within the scope o f the ap- 2 l l pended claims without departing from the spirit of the invention. c

In said drawings: A

' Fig. 1 is a longitudinal section through a ilow regulating device constructed in accordance with one embodiment of this invention;

Fig. 2 is a view similar to Fig. 1 of a second Where hydraulic cylinders are used afor'the l hoisting of loads many occasions require careful control of the lowering operation because oi'ivariable loads occurring on the hoist from time to time. Where the load is always the same the rate can be determined by a xed orifice type of restricter which regulates the rate of liquid lreturn from the underside of the hoist to the reservoir. Where wide ranges occur in the size of the load this system cannot be resorted to and heretofore the operator has endeavored, by the manipulation of the manual control valve, to obtain some form of control, but most of these control valves are not arranged'to provide accurate control because their sensitivity is not suillciently great. This results from a relatively short movement between fully open and fully closed positions.

In accordance with the present invention a ilow regulator is provided, arranged to be inserted bewhich comprises a cylinder having a piston |I` which can be lifted by introducing pressure liquid beneath it an-d loweredby introducing .pressure liquid above it while drawing out the/liquid from beneath. Liquid under pressure is provided by.

pump l2, receiving its supply from reservoir Il, and delivering liquid either to the underside or upper side of the piston under the selective control oi' the manually operated control valve I5.

When liquid under pressure is delivered to one side of the holst the other side discharges its liquid back through the valve Il to the reservoir.

In order to regulate the -rate at which the liquid is discharged from beneath the piston so as to maintain a substantially uniform hoist lowering rate independent or the load connected to the piston rod I thereof, the ilow control device 2l of the present invention is introduced in the pipe line 2| between the lower side o1' the hoist and the control valve. In Fig. 4 the flow control device 29 is identical andso are all ot the other parts except the hoist which is of the so called single acting type. Here the weight on Vthe pis- -ton rod I5 is relied on i'or lowering' the hoist and no fluid is introduced above the piston for the purpose. The manual valve for controlling the operation of the hoist is shown at 22 and is somewhat simpler than that shown in Fig. 3 at |5 for controlling the double acting hoist.

Referring to Fig. 1 for an understanding of the iiow control device, it will be seen to comprise a suitably cast housing 24 having a rst or hoist port 25 adapted for connection to the lower side of the holst cylinder and a second or control valve port 25 forpconnection to the manually operated control valve 4for the hoist. The rst of these ports .opens into a duct 21 which connects by a horizontal connection 28 with -a parallel duct 29. The second port opens into a chamber 3l at the right end of the housing. A further chamber 3| appears at the left end of the housing. Both of these chambers and the parallel ducts are intersected by a hori- `zontal cylindrical bore 32, plugged at the left end by a screw plug 35 having a. stop lug 34 thereon, and plugged at the right end by a screw plug'35 having a spring receiving cup 35 on its inner end.

The bore `32 mounts for reciprocation, through a small range, a restricter plunger 35 normally positioned with its left end against the stop lug I4 under the action of a spring 40 surrounding a projection 4| on the right end of the plunger and supported between it and the cup 35.

A duct 42 projects downwardly from chamber 3| and a corresponding duct projects downwardlyfrom chamber 30 and the two are connected by horizontal duct 44. An enlarged bore 45 coaxial with 44 extends to the right surface of the housing and the inner end supports a non-circular portion 41 of a restricter plug having a long tapered end 50 movable into the duct 44 to regulate the oriiice between it and duct 43. The position of this restricter plug. 50 is manually adjusted by means of a threaded rod 5| engaged in a plug 52 closing the right end of bore 45. This threaded rod has a reduced end received in a socket in the part 41. Suitable lock and cap nuts, as shown, serve to maintain the adjustment of the rod 5| and to prevent leakage.

The plunger 95 has a small bore 55 extending to near its right hand end and a larger or counter-bore 55 extending through its left end and closed by plug 51 whose inner end provides a spring centering pin 58. A check valve plunger 55 has a skirt 50 slidable in counter-bore 55 and receiving the right end of spring 5|, the left end of which is mounted on pin 55. The tapered right end of the valve plunger 59 seats at the junction of the .bore and counter-bore.

The inner end of bore 55 connects by radial aanwas that they are successively eclipsed by the walls of the bore 32 as the plunger is moved towards the right.

to hoist port 25. Duct 21 is enlarged so that the iluid ilows circumferentially around the outside of plunger l5 in moving from 25 to 25.

This passage just described carries the major portion of the liquid for operating the hoist. A second passage, however, carries some of the liquid as follows: port 25, chamber 30, vertical duct 43, oriilce controlled by 50, duct 44, vertical duct 42, chamber 9|, radial passages 55, counter-bore 55. staggered radial passages 58, duct 21 4and port 25.

When the operator manipulates the control valve to lower the hoist, the chamber beneath the piston is connected to the reservoir and iluid then begins to ow into port 25 of the device of Fig. l, enters duct 21 and passages 58 to counter-bore 55, where it immediately closes check valve plunger 59, assisted by its spring. Liquid then flows out through radial ports 55 into chamber 3|, into vertical duct 42, connecting horizontal duct 44, vertical duct 43, chamber 30 and port 25. With no load on the hoist, the adjusting screw 5| is manipulated to initially regulate' the orlce controlled by the conical member 55 to provide the desired rate of lowering for the hoist. This no-load rate then automatically becomes the rate at which the hoist is lowered under any condition of loading because of the action now about to be explained.

It will be noted that the right head of valve plunger 35 is exposed to the low pressure existing in chamber 39 because of its connection its spring 49 to progressively reduce the total ofl the exposed areas of the staggered passages 55 so that the quantity of oil permitted to ilow to chamber 3| is reduced to the quantity which can pass through the orice controlled by the conical member 55 at the rate at which it would ilow under no load conditions of the hoist.

Whatever the load on the hoist the plunger 35 assumes such a position that the ilow of liquid is restricted thereby to the quantity which can ilow through the semi-permanent restricter at 50 at a predetermined velocity. This condition exists because the left end of the valve plunger is exposed in the fluid in the passage between-the fixed restricter and the variabje restricter. When the hoist is first started on its lowering movement there may be some slight oscillation of the plunger 38, but this soon finds its optimum position and regulates the lowering of the hoist at the'rate predetermined by the setting of the semi-fixed restricter 50.

The check valve 56 is for convenience incorporated in the plunger of Fig. 1 where it simplifles to some extent the machining operations. It need not, however, be so located and in Fig. 2 it is illustrated as positioned in a stationary portion of the housing.

In this figure the parts in general are the` same as in Fig. 1 and the operation is the same. The only differences occur in the positioning of the check valve and hence slightly in the ar rangement of the main plunger. In this case the plunger 38' is bored from the right end as at 55' where a closure plug provides a stud for supporting the spring. Radial bores 63' provide for fluid access from chamber 30 and radial bores 65 permit egress into a vertical duct 10 connected by a horizontal duct 28 with vertical duct 21 leading to hoist port 25.

A threaded vertical bore I2 in the top of the housing between the two main ports accommodates a screw plug 13 centrally bored to provide sliding t for a check valve plunger 'I4 and its spring 15. The end of the plunger seats in the duct 10.

The left end of plunger 38' is bored as at 56' and functions as before described.

In this valve the operation in lowering is identical with that described in connection with Fig. l but on raising the path of the liquid via the check valve is as follows: port 26', chamber 30', passages 63', valve plunger bore 55', radial ports 65', duct 10 to lift check valve 14, duct 28' and port Both of the embodiments of the invention are extremely simple in construction and are thoroughly reliable in operation. They materially simplify the work of the operator who does not have to endeavor to manipulate his control valve to regulate the rate of lowering of the hoist. The valve of the present invention can be constructedas an independent unit as illustrated or it may be combined with the control valve in an obvious fashion.

I claim:

1. A fiow regulating device for connection be tween a hydraulic hoist and the control valve therefor and adapted to maintain a substantially uniform lowering rate for the hoist while permitting a variable lift rate, comprising in combination, a housing having a first or hoist port and a second or control valve port, two passages connecting said ports and providing parallel flow paths therebetween, a semi-xed orifice-type restriction in one of said paths, a check valve in the second path open only to flow from the second port to the first, a valve type restricter including a hollow plunger in the first path between the first port and the first mentioned restricter and having a radial orice communicating with the first port and a second radial orifice communicating with the said first restricter, a spring normally maintaining the plunger so that the said passages are fully open, means adapted to provide pressure unbalance on the said plunger to move it against the spring to restrict one of said orifices and hence the first passage when the pressure at the first port increases, said check valve being arranged within the hollow of said plunger and having one end thereof exposed through said plunger to the control valve port and the other end exposed through said plunger to the hoist port. y

2. A flow regulating device for connection between a hydraulic hoist and the control valve therefor and adapted to maintain a substantialls1 uniform lowering rate for the hoist while permitting a variable lift rate, comprising in combination, a housing having a first or hoist port and a second or control valve port, two passages connecting said ports and providing parallel ow paths therebetween, a semi-fixed orifice-type restriction in one of .said paths, a check valve in the second path open only to iiow from the second port to the first, a variable restricter on the first port side of the orifice type restricter, said variable restricter being constructed as a hollow tubular plunger parted and arranged to be pressure moved to automatically restrict the iiow through the first passage to a quantity equal to that which will pass the orifice-type restricter at minimum lowering pressure, both of said passages extending longitudinally through said plunger and a spring to normally maintain the plunger in a position of minimum restriction.

3. A flow regulator for connection between a hydraulic hoist and a control valve therefor adapted to provide uniform lowering speed irrespective of load comprising in combination, a housing having a hoist port and a valve port, a chamber at each end of said housing, one being connected to the valve port, a bore connecting said chambers, a plunger reciprocably mounted in said bore and having one end in each chamber, a duct also connecting said chambers, a flow restricter in said duct, a pocket connected to the hoist port and intersecting said bore, a longitudinal tunnel extending in said plunger, an opening connecting the tunnel to the chamber which is not connected to the valve port, an opening from the tunnel to said pocket, one of said openings being positioned to be progressively eclipsed by the walls of the bore as the plunger is moved toward the chamber connected to the control valve port, and a spring opposing such movement of the plunger.

4. A flow regulator of the type described comprising in combination, a housing having a hoist port and a control valve port, a pair of spaced chambers in the housing, one being connected to the valve port, a bore connecting said chambers, a tubular plunger reciprocably mounted in said bore, having one end in and open to the valve port connected chamber, a duct also connecting said chambers and providing a flow restriction, a pocket connected to said hoist port and intersecting said bore, an opening through the plunger Wall connecting its interior to said pocket, a second opening in the plunger wall connecting its interior to the other chamber, a spring biasing the plunger toward the last mentionedchamber, at least one of said plunger wall openings being positioned to be gradually eclipsed by a wall of the bore as the plunger is moved against said bias to restrict the flow from the pocket to the second chamber and a check valve in said plunger separating the open end thereof from the wall opening leading to the pocket and opening towards the pocket.

5. A iiow regulator of the type described comprising in combination, a housing having spaced 7 chambers and an intermediate pocket, a hoist port i'or said pocket and a control valve port for one of said chambers, a bore connecting said a semi-permanent iiow restrictor, the hollow center of the plunger being permanently in free communication with the ported chamber. the hollow center of the plunger being in communication with the other chamber and with the pocket, a check valve wholly housed in said plunger and separating said last mentioned communication from the nrst whereby the plunger hollow is divided into two parts arranged for ow only from the nrst communication to the last and means to eclipse at least one of the last two communications as the valve plunger is moved against the bias by excess pressure in the unported chamber due to iiow through the plunger from the pocket.

8. A ilow regulator as denned in claim 3 in which the tunnel is open to the chamber connected to the valve port, and a check valve is arranged in the tunnel to permit iiow Yfrom the 25 port connected chamber to the pocket but not vice versa.

7. A ilow regulator of the type described comprising in combination, a housing having spaced chambers and an intermediate pocket, a hoist port for said pocket and a control port for one of said chambers, a bore extending from chamber to chamber and through said pocket, a hollow plunger reciprocabiy mounted in said bore with 8 ends extending into each. chamber, means biasing the plunger toward the unported chamber, a duct connecting said chambers and having an adjustable ilow regulator therein, a check valve separat. ing the plunger hollow into an inlet and a discharge compartment, means placing said inlet compartment always in communication with the ported chamber. means placing the outlet compartment in communication with the remaining chamber and means placing the outlet compartment into communication with said pocket, at least one of said last two means being positioned to be progressively eclipsed by walls of said bore as the plunger is moved against said bias by pressure ,in the unported chamber.

WILLIAM T. STEPHENS.

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

UNITED STATES PATENTS Tucker Apr. 27, 1943