WO2005038267A1

WO2005038267A1 - A selecting and directing arrangement

Info

Publication number: WO2005038267A1
Application number: PCT/SE2004/001449
Authority: WO
Inventors: Bengt Olsson
Original assignee: Bengt Olsson
Priority date: 2003-10-17
Filing date: 2004-10-12
Publication date: 2005-04-28
Also published as: SE524901C2; EP1680604A1; SE0302743L; SE0302743D0

Abstract

A selector and direction device for hydraulic components, such as pistons and motors, comprises a selector valve in the form of a double three-port valve (20). A direction valve (10) is connected to the inputs of the selector valve and is also connectable to a source of hydraulic pressure (2), wherein the direction valve determines the direction of flow through the selector valve. The device also comprises an control unit for activation of the selector valve and the direction valve. Activation of the direction valve thereby controls the direction of fluid flow through the component to be controlled and activation of the selector valve controls whether fluid flows to the unit to be controlled. A rational, economic, and flexible system is provided which as far as possible is based on standard valves of a simple and reliable kind which together can be assembled to units of different sizes for the control of an optional number of components.

Description

Selector and direction device

The present invention relates to an arrangement for controlling and regulating hydraulic and pneumatic components, such as heavy-duty piston-cylinder devices and motors. The invention is particularly suited for application within the broad field of mobile hydraulics, including, for instance, contractor-owned machines, forestry machines and agricultural machines.

BACKGROUND OF THE INVENTION

There are found within this field many tool or implement manufacturers that have differing servo-function requirements. Developed machines at times include up to 10 single-acting and double-acting piston-cylinder devices and some motors from which the driver shall be able to choose and control directionally. A standard tractor is often used to tow the tool or implement, wherewith the requisite hydraulic power is obtained from the hydraulic pump of the tractor. For reasons of a practical and power transmission technical nature, such as convenient interconnection or inter-coupling etc., it is often desired to connect only two hoses between tractor and implement, one hose for the pressure fluid and one hose as a return line. The problem of remote control that occurs - there is often a distance of 4-6 between tractor and implement - is solved by constructing on the implement separate valve blocks that include the correct number of functions, these valve blocks being controlled from the tractor, for instance through the medium of mechanical cables or electric cables that activate valve-actuating electromagnets. This known method is relatively awkward and expensive, particularly when large valve systems are required and the implement or tool is produced in only a few examples, requiring complicated valve blocks to be produced in small numbers. SUMMARY OF THE INVENTION

One object of the present invention is to solve the aforesaid problems and to provide a rational, economic and flexible system that is based, as far as possible, on valve units of a simple and reliable kind that can be built together to provide different larger units for the selective control of a number of components.

The characteristic features of an inventive selecting and directing arrangement will be apparent from the characterising clause of the accompanying claim 1.

There is also provided an hydraulic system that includes an hydraulic pump and a selecting and directing arrangement according to the invention.

In one particular preferred embodiment of the invention, the directional valve has the form of a double 3-port valve. The fact that all valves are of one and the same type affords constructional and storage advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail by way of example with reference to the accompanying drawings, in which

Figure 1 is a general view of an inventive selecting and directing arrangement, with first and second valves shown in a rest state; Figure 2 is a view corresponding to figure 1 but with the first and second valves shown in an activated state; and

Figure 3 illustrates the electrical components of a manoeuvring unit for controlling the arrangement illustrated in figures 1 and 2.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The invention will now be described in more detail with reference to a preferred embodiment.

Figure 1 shows three mutually identical double 3-port valves referenced 10, 20 and 30 respectively. Such valves (also called 6/2-valves) are quite common. The valves shown in figure 1 together form a selecting and directing arrangement, indicated generally by reference numeral 1. The reference numerals used to identify the same part of respective valves differ solely by the first digit, such that the component parts of the first valve 10 begin with the digit "1", the component parts of the second valve with the digit "2" and the component parts of the third valve with the digit "3". Solely the first valve 10 will be described in detail in the following text.

The first valve of the illustrated example comprises an upper and a lower housing part 11a, 1 lb, with three ports in each housing part, which include an inlet 12a and two outlets 13a, 14a in the upper housing part and an inlet 12b and two outlets 13b, 14b in the lower housing part. The valve also includes a spring-biassed, electrically manoeuvred control rod 15 which includes sealing plugs 16a, 17a for respective outlets of the upper part, and sealing plugs 16b, 17b for respective outlets of the lower housing part. The control rod is sealed in the walls of said housing parts.

The valve 10 has two states, these being a spring-held rest (shown in fig.l) in which the sealing plugs 16a, 16b carried by the control rod block respective outlets 13a and 13b, and an active state (shown in fig.2) in which the control rod is urged by a magnetic force against the force of the biasing spring, wherewith the seals or plugs 17a, 17b plug respective outlets 14a and 14b. The outlets 13a, 13b are thus open in this latter state of the valve.

The upper inlet 12a of the first valve 10 is coupled to a pressure source, such as to a hydraulic pump 2 of a tractor (not shown), whereas the lower inlet 12b is coupled as a return line to the suction inlet of said pump 2, normally via a tank (not shown). The outlets 13a and 14b of the first valve 10 are coupled to the lower inlet 22b of the second valve 20 via a T-pipe 19. Correspondingly, the outlets 13b and 14b of the first valve are coupled to the upper inlet 22a of the second valve via a T-pipe 18. The outlets 14a and 13b mutually coupled by the pipe 18 are never open simultaneously. This also applies to the outlets 13a and 14b mutually coupled by the pipe 19. This results in the following function.

When the control rod 15 and its sealing plugs 16a, 16b, 17a ,17b are located in the position shown in figure 1, the hydraulic pressure is delivered from the hydraulic pump 2 to the upper inlet 22a of the second valve 20 and the lower inlet 22b is connected with the return line. On the other hand, the reverse function is obtained when the control rod 15 is moved to its lower position, in other words the hydraulic flow is transferred to the lower inlet 22b of the second valve via the first valve, wherewith the upper inlet 22a connects with the return line. In the case of this coupling, the first valve 10 functions as a directional valve which chooses the direction of the hydraulic flow from the hydraulic pump 2. The outlets 24a, 24b of the second valve 20 are coupled to corresponding respective inlets 32a and 32b on the third valve 30, via respective pipes 28 and 29. The second outlets 23a and 23b are coupled to respective hydraulic connections 42a and 42b on a first double-acting piston- cylinder device 40 via pipes 41a, 41b, wherein the piston-cylinder device 40 shall be controlled by means of the selecting and directing arrangement 1. Correspondingly, the outlets 33a and 33b of the third valve 30 are connected via respective pipes 51a and 51b to respective hydraulic connections 52a and 52b on a second double-acting piston-cylinder device 50 to be controlled. With this coupling, the second and third valves 20, 30 function as selection valves with which, upon activation, it is elected to connect a respective selection valve to a respective load 40 or 50.

When the drive source is a non-load-sensing pump so that continuos circulatory pumping is required, a pipe 38 is provided between the outlets 34a and 34b of the third valve 30.

The modus operandi of the arrangement 1 will now be described with reference to figures 1 and 2. Wlien the first valve is in a rest or idle state (shown in fig. 1) the fluid will flow in one direction in through the upper inlet 22a of the second valve and then through subsequent valves. When the first valve is activated (see fig. 2) the fluid will flow in the opposite direction through subsequent valves, i.e. into the lower inlet 22b of the second valve and so on. Thus, control of the first valve results in a directional change with respect to connected loads, such as the piston-cylinder devices 40 and 50.

Figure 1 shows the second valve 20 in a rest state, in which the sealing plugs 26a, 26b close the outlets 23a, 23b to which the first piston-cylinder device 40 is connected. As a result, the first piston-cylinder remains stationary with the second valve in a rest state. On the other hand, when the second valve is activated (see fig. 2) the outlets 23a, 23b are open and fluid is allowed to flow through the second piston-cylinder device 40. Thus, control with respect to the second valve enables the load 40 connected thereto to be engaged and disengaged.

When the first and the second valves 10, 20 are activated simultaneously, the piston rod of the first piston-cylinder device will move upwards (see fig. 1) whereas when the first valve is in its rest state and the second valve is activated, the piston rod of said device will move downwards.

The preferred embodiment includes double 3-port valves which are activated by an electromagnetic force. This enables the electric circuits required to actuate the electromagnet/electromagnets in the sequences desired for different functions and directions to be achieved with the aid of electric cables between tractor and implement and also with the aid of switches provided in the tractor. One smart way of selecting a particular piston-cylinder device from among other devices and controlling said selected device in a directional sense is to provide a pair of press-button switches 43 a, 43b and 53 a, 53b respectively for each piston-cylinder device, as illustrated in figure 3, and operating said device in one direction by pressing the upper switch, and in an opposite direction by pressing the lower switch, and parking the piston rod in a selective position by refraining from pressing any of the switches. The electrical operating unit 60 in figure 3 is thus designed so that when closing one switch of a switch pair intended for manoeuvring a load, both the first valve 10, i.e. the directional valve, and the selection valve relevant at that time are activated. On the other hand, when the other switch of said pair of switches is closed, only the selector valve relevant at that point in time is activated.

The electromagnets symbolised in figure 3 have the same order of sequence as the corresponding valves in figure 1 , as seen from left to right. Shown in broken lines in the electrical system of figure 3 is an extra electromagnet which is additional to the magnets required for the valves shown in figure 1. As will be understood, the electrical system according to the concept of the present invention is also flexible and exchangeable. It will also be understood that the manoeuvring or operating unit shown in figure 3 is highly usable in practice, both in the illustrated or in an expanded construction.

Although the selecting and directing arrangement according to the invention has been described with reference to a preferred embodiment thereof it will understood that this embodiment can be varied or modified within the scope of the accompanying claims without deviating from the concept of the invention. For example, the first valve 10 illustrated as a double 3-port valve may consist of any other general directional valve with which the direction of hydraulic pressure from the hydraulic pump 2 can be controlled. Furthermore, the system illustrated in figure 1 can be further extended or expanded. For example, a fourth and further valve may be connected downstream of the third valve, these additional valves being adapted to control third and additional double-acting piston- cylinder devices.

Although double-acting piston-cylinder devices 40, 50 have been described as those components driven by the inventive arrangement, it will be understood that the inventive arrangement may also drive other types of loads, such as a reversible hydraulic motor.

The system described is adapted for driving a non-load-sensing pump. In the case of load sensing systems that include a self regulating pump or in those cases when continuos circulatory pumping of the fluid can be affected by a separate circuit and supply valve which takes fluid from this upstream flow prior to the first valve, the outlets 34a, 34b may be plugged or some other function may be instigated or the fluid led to a tank via a separate return line.

It is emphasised that double 3-port valves may have different configurations and need not necessarily comprise a physical combination of said housing parts. For instance separate housing parts (often designated 3/2-valves) each including an individual electromagnet with associated control rod for simultaneous activation are also considered to constitute double 3-port valves in accordance with the invention.

The electrical system shown in figure 3 is adapted for the system illustrated in figures 1 and 2. Naturally, this electrical system is also flexible and exchangeable in accordance with the concept of the invention and can readily be supplemented by connecting more valves and loads. Such an extension including the addition of a further valve is shown in broken lines in figure 3. The manoeuvring unit shown in figure 3 is highly usable in practice, either in its illustrated state or in an expanded state.

Practical use is also found in the priority that can be assigned to a given component independently of where its connecting selector valve is placed downstream of the directional valve 10. The selection valve 20 coupled directly to the directional valve has the highest priority and the priority of following selector valves is allotted a lower status the more distant the valves. When the valves 20 and 30 of the illustrated example are activated simultaneously, solely the piston-cylinder device 40 is controlled and thus has priority over the piston-cylinder device 50.

Claims

1. A selecting and directing arrangement pertaining to hydraulic components, such as piston-cylinder devices and motors, comprising

- a selection valve in the form of a double 3-port valve (20) comprising first and second chambers (21a, 21b) having a respective inlet (22a, 22b) and first and second respective outlets (23a, 24a, 23b, 24b), wherein opening and closing of the outlets are controlled pair-wise by means of a control rod (25), and wherein an outlet (23a, 23b) of respective chambers is connectable to a component (40) to be controlled, characterized by a directional valve (10) connected to the inlets of said selection valve and connectable to a source of hydraulic pressure (2), wherein said directional valve determines the direction of flow through the selector valve; and by - a manoeuvring unit (60) for activation of the selection valve and the directional valve, whereby activation of the directional valve controls the direction in which fluid will flow through the component to be controlled, and activation of the selection valve controls whether or not fluid shall flow to the component to be controlled.

2. The arrangement according to claim 1, characterized in that the directional valve (10) includes a double 3-port valve (10).

3. The arrangement according to claim 2, characterized in that the directional valve (10) includes first and second chambers (11a, l ib) that have a respective inlet (12a, 12b) and first and second respective outlets (13a, 14a, 13b, 14b), whereas opening and closing of the outlets are controlled pair- wise by means of a control rod (25), and in that the arrangement further includes: means (18) for connecting one inlet (22a) of the selection valve with the first outlet (14a) of the first chamber of said directional valve, and the second outlet (13b) of the second chamber of said directional valve; and means (19) for connecting the second inlet (22b) of the selection valve with the second outlet (13a) of the first chamber of said directional valve, and the first outlet (14b) of the second chamber of said directional valve.

4. The arrangement according to any one of the preceding claims, characterized by a further selection valve (30) in the form of a double 3-port valve (30) connected to the outlets of the selection valve (20).

5. The arrangement according to any one of the preceding claims, characterized in that the manoeuvring unit (60) is adapted to enable the choice of component and its working direction to be made in one operation.

6. The arrangement according to any one of the preceding claims, characterized in that the manoeuvring unit (60) includes electromagnets (15a, 25a, 35a) and switches (43a, 43b, 53 a, 53b) for constructing electric circuits that drive the electromagnets.

7. The arrangement according to claim 6, characterized in that the manoeuvring unit (60) includes a first pair of electric switches (43a, 43b) which are coupled so that when one switch (43 a) in said pair is closed, both the directional valve (10) and the selection valve (20) are activated, and when the other switch in said pair is closed solely the selection valve is activated.

8. The hydraulic system comprising a hydraulic pump (2), characterized in that the hydraulic pump has connected thereto a selecting and directing arrangement according to claim 1.

9. The hydraulic system according to claim 8, characterized in that the hydraulic pump is a tractor-mounted hydraulic pump (2).