US3737049A - Step volume control - Google Patents

Abstract

A step volume control affording control over the rate at which fluid under pressure is supplied to a pressure fluid-operated instrumentality. Fluid is supplied under pressure in multiple flow paths, with the flow rate in such paths having a predetermined proportionate relationship. The fluid in such flow paths is directed into a common inlet port of a main control valve. The control valve is connected to the pressure fluidoperated instrumentality, and with the valve open, fluid flowing into the inlet port is directed to the instrumentality. Selectively operated means is provided for diverting pressure fluid flowing in at least one of said flow paths, whereby such fluid bypasses the main control valve to be recirculated directly back to the source of pressure fluid. The control valve, and selectively operated means, may be remotely electrically controlled.

Description

United States Patent 1 Farmer [45] June 5, 1973 54 STEP VOLUME CONTROL Primary ExaminerRichard E. Aegerter 7 Assistant ExaminerMerle F. Maffei [75] Inventor. Stanley E. Farmer, Gresham, Oreg. Att0mey KOliSch, Hartwell & Dickinson [73] Assignee: Cascade Corporation, Portland,

Oreg. [57] ABSTRACT [22] Filed: Mar. 19, 1971 -A step volume control affording control over the rate Appl. No.: 126,230

US. Cl. ..2l2/35 R, 212/59, 60/97 E [51] Int. Cl ..B66c 23/54 [58] Field of Search ..2l2/35, 58, 59, 35 HC; 60/97 E [56] References Cited UNITED STATES PATENTS 2,501,483 3/1950 Taylor .;.2l2/35 l-lC 2,755,943 7/1956 Payne et al. .21 2/35 2,985,142 5/1961 Aiken ..2l2/59 3,039,266 6/1962 Schenkelberger ..60/97 E at which fluid under pressure is supplied to a pressure fluid-operated instrumentality. Fluid is supplied under pressure in multiple flow paths, with the flow rate in such paths having a predetermined proportionate relationship. The fluid in such flow paths is directed into a common inlet port of a main control valve. The control valve is connected to the pressure fluid-operated instrumentality, and with the valve open, fluid flowing into the inlet port is directed to the instrumentality. Selectively operated means is provided for diverting pressure fluid flowing in at least one of said flow paths, whereby such fluid bypasses the main control valve to be recirculated directly back to the source of pressure fluid. The control valve, and selectively operated means, may be remotely electrically controlled.

5 Claims, 4 Drawing Figures STEP VOLUME CONTROL This invention relates to the control of the flow of fluid under pressure to a fluid pressure operated instrumentality, such as a hydraulic ram or motor. More particularly, the invention concerns a step volume control, whereby the volume rate at which pressure fluid is delivered to the instrumentality may be adjusted in steps, thus to control the actuation speed of such instrumentality.

The invention has particular utility, andis described herein, in conjunction with the control of a pressure fluid-operated instrumentality where it is desired to control the actuation of such instrumentality from a remote point or station.

By way of example, in controlling movements of a load handler such as a'crane or load-handling boom, it is frequently desirablethat an operator be able to control such movements from a location remote from the boom itself, as for example a location directly adjacent the point where the load being handled is to be deposited. The remote control of a pressure fluid-operated instrumentality, through a portable valve which actually forms part of the conduit system connecting the source to the instrumentality, is not practicable in the usual instance. This type of control necessitates the provision of elongated,,flexible hoses to enable the control valve to be moved from one location to another. Such hoses are expensive and are prone to damage, and present problems in reeling in and paying out the hoses, particularly in cold weather when the hoses tend to stiffen. Another manner of remotely controlling the operation of a fluid motor comprises introducing electrically operated valves. However, the usual electrical control system is a binary type system, and as a result with an electrical approach the operator usually loses an ability to control the speed of operation. Further explaining, when an operator handles directly the valve which controls the supply of pressure fluid, he may feather the valve to slow down or increase the speed of the motor to which the fluid is being delivered, but with a binary type electrical control system this type of operation is not permitted. y

In general terms, an object of this invention is to provide a control system for a pressure fluid-operated instrumentality such as a motor, which affords control over the speed of actuation of such motor through the expedient of supplying pressure fluid to the instrumentality in multiple paths, and diverting, when desired, pressure fluid flowing in one path, whereby such bypasses the instrumentality and is returned to the source of fluid under pressure.

Another object of this invention to provide a remote control for the volume of pressure fluid being supplied a pressure fluid-operated instrumentality, where control is by stepping up or stepping down the volume of pressure fluid delivered to the instrumentality.

One embodiment of the invention contemplates the provision of a step volume control for controlling the actuation of a pressure fluid-operated instrumentality, where such instrumentality is bidirectional (as exemplified by a reversible motor or a double-acting ram), and

the step volume control includes a primary control valve and a flow divider in series with each other, Interposed between the instrumentality and a source of pressure fluid. The flow divider feeds multiple conduits, and these conduits combine to supply fluid to a common port in the control valve. Selectively operated means is provided in at least one of the conduits handling the fluid flowing from the divider, which is adjustable to divert pressure fluid from flowing through such conduit into the control valve, and to return such fluid to the source of pressure fluid.

These and other objects and advantages are attained by the invention, which is described hereinbelow in conjunction with the accompanying drawings, wherein:

FIG. 1 illustrates, in very simplified form, a mobile load handler, such as a vehicle with boom, of the type that might have incorporated therewith the remote step volume control contemplated by the invention;

FIG. 2 is a schematic view of a hydraulic circuit incorporating the principals of the invention;

FIG. 3 is another schematic view, illustrating a modification of the invention; and

FIG. 4 illustrates schematically yet another modification of the invention.

Referring now to the drawings, and first of all more particularly to FIG. 1, here there is illustrated a mobile load handler, such as a mobile crane 10, whose operation might advantageously be controlled using the step volume control of the invention. The crane includes a boom 12 supported on the frame of the crane for up and down swinging movement, whereby the tip of the boom may be raised and lowered. Producing up and down movement of the boom is a fluid-operated motor, more specifically, a double-actingpiston cylinder or ram, 14.

Ram 14 may be extended, or contracted, by controlling theadmission of pressure fluid such as hydraulic fluid to opposite ends of the ram. As is conventional with such a mobile load handler, included on the frame of the vehicle is the usual pump and reservoir or sump system for the hydraulic fluid, which functions as a source of fluid under pressure in the unit. Up and down movement of the boom, and the speed with which such boom is raised or lowered, is controlled by controlling the supply of pressure fluid to the ram. The rapidity of movement in the boom is determined by the rapidity at which the ram is actuated, the latter being a function of the rate at which fluid under pressure is delivered to the ram.

Referring now to FIG. 2, here there is illustrated schematically a hydraulic circuit such as might be utilized in the supply of pressure fluid to ram 14. In the drawing, the usual source of fluid under pressure has been given the general reference numeral 16, such including a pump shown at 17 and a reservoir or sump 18 to which the suction side of the pump is connected.

As contemplated herein, a control valve and a flow divider are provided, and conduit means connects these in series and with these elements disposed between the source of fluid under pressure and the ram 14. Further contemplated is selectively operated means associated with one of multiple fluid flow paths produced by the flow divider, for diverting the pressure fluid flowing in such path whereby such bypasses ram 14 and is returned to sump 18 without actuating the ram. It should be obvious that with the selectively operated means adjusted to produce such a by pass of fluid, the volume rate of fluid under pressure delivered to the ram is a fraction of what it is when there is no by pass of the ram. In the embodiment of the invention shown in FIG. 2, the control valve has been given the general reference numeral 20, the flow divider the reference numeral 22, and the conduit means connecting these in series the general reference numeral 24.

More specifically, flow divider 22 is conventional, in that such includes an input port 22a which receives fluid under pressure delivered thereto. The flow divider divides this fluid into two flow paths, one including the output port 22b, and the other the output port 22c. The volume rate of flow through one port has a fixed proportionate relationship to the volume rate of flow through the other port. The input port is shown connected to the pump by conduit 30.

A conduit is shown for each flow path produced by flow divider 22. Thus, conduit 32 is shown connected to output port 22b, and conduit 34 is shown connected to output port 220. These two conduits are shown connected to a common conduit 36, the latter connecting with control valve 20, more specifically, input port a of the control valve.

Considering control valve 20, in addition to port 20a, the valve includes ports 20b and 200 which are connected through conduits 38 and 40 to opposite ends of ram 14. Cooperating with port 20a in providing for the supply and exhaust of fluid under pressure to and from the valve is another port 20d.

The valve is adjustable, through energizing of electric solenoid 42, to produce flow through the valve as indicated by the arrows in the right hand part of the rectangle which represents the valve, i.e., in parallel flow paths through the valve. With energizing of solenoid 44, the flow through the valve is as illustrated at the left of the diagram representing the valve, or in crossed flow paths. Energizing of solenoid 42 therefore pro duces extension of the ram 14, whereas energizing of solenoid 44 results in contraction of such ram. With the valve in the neutral position shown, fluid introduced to the valve through conduit 36 is returned by conduit 46 to the source of fluid under pressure.

By including the solenoids described, valve 20 is remotely electrically controllable. Conductors 48, 50 are shown for the solenoids. These in a remote control system are connected with remotely located, operator controlled switches.

Referring again to FIG. 2, connecting with conduit 34 is a conduit 58 leading to port 600 of an electrically operated shutoff valve 60. The valve is ganged to a solenoid 62. The valve has two adjusted positions, with flow being through the valve to port 60b, as represented by the arrow at the top of the rectangle representing the valve, with the valve in one position. FLow through the valve is closed off with the valve in another adjusted position, as illustrated by the bottom portion of the rectangle representing the valve. Connecting port 60b with sump 18 of the source is a conduit 64.

In conduit 34 and located toward port 20a of the control valve from where conduit 58 connects with conduit 34, is a check valve 66. With shutoff valve 60 closed to prevent flow through conduit 64, the check valve opens with fluid under pressure in conduit 34, to enable fluid flowing out of port 22c and into conduit 34 to join with fluid flowing in conduit 32. With shutoff valve 60 open to permit flow through the valve, the check valve closes to prevent fluid flowing in conduit 32 from flowing back into conduit 34 toward the flow divider.

Solenoid 62, which is energized and deenergized to actuate valve 60, is electrically connected to a switch device, not shown, which may be remotely located. Ordinarily, such switch together with the switches controlling solenoids 42, 44 would comprise a bank of switches adapted to be actuated by an operator of the boom located at a remote location.

The operation of the construction as so far described will now be explained. For the purpose of illustration, it will be assumed that the rated capacity of pump 17 is 15 gallons per minute, and it will further be assumed that flow divider 22 is effective to produce a flow rate of 4 gallons per minute in conduit 32 and eleven gallons per minute in conduit 34.

To obtain a relatively slow speed of actuation in ram 14, valve 60 is opened whereby the flow through conduit 34 is diverted by the valve to be returned to the source of fluid under pressure, more particularly, sump 18. The flow through conduit 32, i.e., 4 gallons per minute, is directed to the control valve. This flow produces extension or contraction of ram 14, depending upon the particular adjustment that has been made in control valve 20. Note that slow operation is possible both with contraction and with extension of the ram.

To obtain fast actuation, valve 60 is closed. With this adjustment of the valve, all of the fluid pumped by the pump is directed to control valve 20. Depending upon the particular adjustment that has been made in the control valve, motor 14 is contracted or extended at a substantially faster rate of speed.

The construction disclosed is relatively simple, and because of its simplicity, is readily incorporated with a mobile power-operated instrumentality such as the hydraulic motors commonly found in a mobile crane. The construction also is modifiable without appreciable change therein to enable three or more regulated speeds, rather than the two permitted by the embodiment shown in FIG. 2.

Referring to FIG. 3, shown in the figure is conduit 30, which is the same as conduit 30 illustrated in FIG. 2. Conduit 36 is also shown, which is the conduit feeding fluid under pressure to the control valve. interposed between these two conduits are a pair of flow dividers, shown at and 72.

Connecting with one of the output ports of flow divider 70 is a conduit 74 which extends directly to a connection with conduit 36. The other output port of the flow divider 70 is connected to the input port of flow divider 72.

One of the output ports of flow divider 72 is connected by conduit 76 to conduit 36, conduit 76 including a check valve 78. Between the check valve and the output port of the flow divider is a conduit 80 leading to a solenoid-operated shutoff valve 82 which is like shutoff valve 60 shown in FIG. 2. The exhaust port of this valve leads to the sump in the source of fluid pres sure through conduit 84.

The other output port of flow divider 72 is connected to a conduit connecting with conduit 36 and including a check valve 92. Connecting with this conduit 90 between the check valve and the flow divider is a conduit 94 leading to a shutoff valve 96, which shutoff valve has an output port connected to the sump through a conduit 98.

With the construction described, and assuming that the flow dividers and associated structure are substituted for the flow divider 22 and associated structure shown at FIG. 2, to obtain the slowest possible speed of actuation in ram 14, valve 82 and 96 are both open, so only that pressure fluid flowing in conduit 74 is introduced to the main control valve. To obtain a somewhat faster speed, one of the shutoff valves 82, 96 is closed, partially to shutoff the diversion of pressure fluid from control valve 22. An even faster greater speed of actuation of the main ram results with closing of both the shutoff valves.

Again, as in the modification of the invention shown in FIG. 2, the valves 82, 96 are remotely,-electrically controlled, enabling the control of ram speedfrom a remote location by an operator controlling switch devices connected to the solenoids by flexible electrical conductor connections.

In the modification of the invention shown in FIG. 2, pump 17 and flow divider 22 together constitute mechanism drawing fluid from reservoir 18 operable to produce a flow of pressure fluid in multiple flow paths. In FIG. 4 another modification of the invention is shown, where such mechanism comprises multiple pumps drawing fluid from reservoir 18.

In FIG. 4, two pumps are provided for producing a flow of pressure fluid in conduits 32, 34, as exemplified by pumps 102, 104. These are in tandem, i. e., are driven by a common shaft. The pumps draw fluid from reservoir or sump 18 through conduits 106, 108. Conduit 36 leads to the inlet part of a control valve as in FIG. 2. Fluid is diverted from the control valve, by opening shutoff valve 60, also as explained in FIG. 2.

With pump 102 having a rated capacity of, for example, 4 gallons per minute, and pump 104 a rated capacity of l 1 gallons per minute, a proportioned rate of flow is produced in conduits 32, 34 which is the same as that produced by flow divider 22 in FIG. 2. A relatively fast speed of actuation is obtained in a ram supplied with fluid from conduit 36 by closing valve 60, and a slower speed is obtained by opening the valve.

It should be apparent from the above that the step volume control of the invention provides a very practical and satisfactory answer to the problem of controlling a pressure fluid-operated instrumentality. The control does not include expensive and complicated servomechanisms, nor does it necessitate the inclusion of flexible hose connections, introducing the problems generally discussed above.

While preferred embodiments of the invention have been described herein, it is obvious that changes and variations are possible without departing from the invention.

It is claimed and desired to secure by Letters Patent:

1. In combination with a mobile load handler including a boom, a double-acting hydraulic ram for adjusting the position of the boom, and a source of fluid under pressure having a point of delivery through which fluid under pressure is supplied and a point of return through which fluid is returned to the source,

a flow divider,

conduit means connecting the point of delivery of said source and said flow divider whereby fluid under pressure is delivered thereinto, said flow divider being constructed to divide the fluid under pressure delivered therein into multiple flow paths conduit means connecting the flow divider and said supply port of said control valve whereby fluid in all of said flow paths is channeled into said supply port of said control valve, conduit means connect ing said exhaust ,port and said point of return of said source, and

means including a remotely electrically controlled valve for directing the pressure fluid flowing in one of said flow paths whereby such bypasses said firstmentioned control valve to be returned to said point of return of said source.

2. In combination with a mobile load handlerincluding a power-operated instrumentality for changing the position of a load, a bidirectional fluid-powered motor means for powering said instrumentality having a pair of ports which replace one another as supply ports with a change in the direction of motor operation, and a reservoir for the pressure fluid for operating said motor,

a remotely electrically controlled control valve having supply and exhaust ports and connections with said motor means, said valve being adjustable to direct fluid entering said supply port selectively to) either of said ports of said motor means with a re-j turn for pressure fluid being provided for the other of said ports of said motor means, mechanism drawing fluid from said reservoir operable to produce a flow of pressure fluid in multiple paths,

conduit means connecting said mechanism and said control valve whereby fluid flowing in all of said multiple paths is channeled into said supply port of said control valve, and

means including a remotely electrically controlled diverting valve adjustable to a bypass position and operable in this position to divert pressure fluid flowing in said mechanism in one of said paths whereby the same bypasses said control valve to be returned to said reservoir.

3. The combination of claim 2, wherein said mechanism drawing fluid from the reservoir comprises multiple pumps, each producing a flow of pressure fluid in a path.

4. The combination of claim 3, wherein said pumps are driven in tandem.

5. The combination of claim 2, wherein the mechanism drawing fluid from the reservoir comprises a pump having its discharge connected to a flow divider which flow divider produces a flow of pressure fluid in multiple paths.

* k k t

Claims (5)

1. In combination with a mobile load handler including a boom, a double-acting hydraulic ram for adjusting the position of the boom, and a source of fluid under pressure having a point of delivery through which fluid under pressure is supplied and a point of return through which fluid is returned to the source, a flow divider, conduit means connecting the point of delivery of said source and said flow divider whereby fluid under pressure is delivered thereinto, said flow divider being constructed to divide the fluid under pressure delivered therein into multiple flow paths havaing a predetermined proportionate relationship of volumetric flow, a remotely electrically controlled control valve having supply and exhaust ports and connections with each end of said ram, said valve being adjustable to direct fluid entering said supply port selectively to each end of the ram with a return being provided through the valve for said exhaust port, conduit means connecting the flow divider and said supply port of said control valve whereby fluid in all of said flow paths is channeled into said supply port of said control valve, conduit means connecting said exhaust port and said point of return of said source, and means including a remotely electrically controlled valve for directing the pressure fluid flowing in one of said flow paths whereby such bypasses said first-mentioned control valve to be returned to said point of return of said source.

2. In combination with a mobile load handler including a power-operated instrumentality for changing the position of a load, a bidirectional fluid-powered motor means for powering said instrumentality having a pair of ports which replace one another as supply ports with a change in the direction of motor operation, and a reservoir for the pressure fluid for operating said motor, a remotely electrically controlled control valve having supply and exhaust ports and connections with said motor means, said valve being adjustable to direct fluid entering said supply port selectively to either of said ports of said motor means with a return for pressure fluid being provided for the other of said ports of said motor means, mechanism drawing fluid from said reservoir operable to produce a flow of pressure fluid iN multiple paths, conduit means connecting said mechanism and said control valve whereby fluid flowing in all of said multiple paths is channeled into said supply port of said control valve, and means including a remotely electrically controlled diverting valve adjustable to a bypass position and operable in this position to divert pressure fluid flowing in said mechanism in one of said paths whereby the same bypasses said control valve to be returned to said reservoir.

3. The combination of claim 2, wherein said mechanism drawing fluid from the reservoir comprises multiple pumps, each producing a flow of pressure fluid in a path.

4. The combination of claim 3, wherein said pumps are driven in tandem.

5. The combination of claim 2, wherein the mechanism drawing fluid from the reservoir comprises a pump having its discharge connected to a flow divider which flow divider produces a flow of pressure fluid in multiple paths.

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