FR2494805A1 - Hydraulic selector valve for tractor - includes lever-controlled spool directing hydraulic fluid to existing accessories or to auxiliary accessories - Google Patents

Abstract

The selector valVe unit for the hydraulic system of an agricultural tactor, is adapted to fit directly to the tractor auxiliary hydraulic interface and to be fitted directly with one or more directional control valves feeding auxiliary devices. The supply from the tractor hydraulic pump enters the chamber (13) and is directed by way of a spool (14) which is controlled by a lever (5). It s directed to either the exsting hydraulic accessories through a passage (11) or to a chamber (15) from where it passes to the directional control valves and the auxiliary accessories. A return line (16,12) s permanently connected.

Description

 The present invention relates to a hydraulic selector valve and relates more particularly to a valve which allows the control of auxiliary hydraulic members from the hydraulic circuit of a tractor used in agriculture.

 Most tractors used for agricultural work are equipped with a hydraulic circuit in which is incorporated an oil recirculation system comprising a reservoir and an oil pump driven by the tractor engine. In general, the pump can control the operation of different hydraulic working members which can be connected to a rear connection device. Auxiliary hydraulic devices can be coupled to the tractor circuit through an interface to which the oil inlet and outlet pipes can be connected. Each auxiliary device must generally have a directional control valve associated with it, and the piping which connects the tractor interface to each directional control valve is bulky and takes a long time to assemble. external auxiliary supply pump introduces additional complexity into the piping.

 The present invention aims to provide an improvement by which the auxiliary hydraulic devices and an auxiliary pressure supply for these can be easily interconnected with the hydraulic circuit of the tractor.

 To do this, the invention relates to a device with selector valves for the hydraulic circuit of a tractor used in agriculture, this tractor comprising an auxiliary interface which has (a) a supply orifice connected to the hydraulic pump. tractor; (b) a return port for the hydraulic fluid; and (c) an inlet orifice for supplying hydraulic fluid to auxiliary devices, the selector valve device being adapted to be adjusted directly on the interface and comprising orifices which communicate respectively with the orifices (a), (b) and (c), the selector valve device being further adapted to be mounted directly with one or more directional control valves arranged side by side and having a supply port (d) which communicates with a port inlet for the directional control valve (s) and a return port which communicates with a return port for the directional control valve (s); the selector valve device also has an auxiliary pressure supply orifice (f) capable of being connected to an auxiliary hydraulic pump and a manually actuated slide valve which can be placed in at least a first and a second position, this valve with drawer providing, in its first position, a first interconnection which connects the supply orifice (a) to the inlet orifice (c) while in its second position, it cuts the first interconnection and achieves a second interconnection between the supply port (a) and the supply port (d), channels being provided in the selector valve device for connecting the auxiliary pressure supply port (f) to the supply port (d) and to connect the return port (e) to the return port (b).

 Preferably, a non-return valve is arranged at the auxiliary pressure supply orifice (f).

 In a preferred embodiment of the invention, the slide valve has a third position in which the above-mentioned first and second interconnections are made simultaneously.

 In a particularly preferred embodiment, the present invention is specially designed to constitute a selector valve device which adapts the interface formed on the top of the cover of the gear boot of a "Massey Ferguson" tractor (registered trademark) to one or more valves directional control hydraulics arranged side by side, of the type known under the name "standard 80 Series".

The present invention will be better understood in the light of the description given below by way of nonlimiting example with reference to the accompanying drawings in which
- Figure 1 is a side view of a selector valve device according to the invention
- Figure 2 is a front view of the same device
- Figure 3 is a top view of the device of Figures I and 2
- Figure 4 is a sectional view taken along line AA of Figure 3
- Figure 5 is a block diagram of the hydraulic circuit of the selector valve device of Figures I to 4;
- Figure 6 is a sectional view similar to Figure 4 but showing an alternative embodiment of the selector valve device according to the invention;
- Figure 7 is a perspective view of an installation in which is incorporated the device of the invention and which comprises directional control valves controlled remotely; and
- Figure 8 is a perspective view of the installation of Figure 7 also connected to an auxiliary pump of the tractor.

 The device according to the invention, shown in Figures I to 3, is designed to adapt the interface formed on the top of the gearbox cover of a "Massey Ferguson" agricultural tractor (Registered trademark) to the hydraulic valve "Vapormatic Series 80" directional control valve, which is a slide valve able to be placed side by side with other valves and capable of controlling a hydraulic device to which it is coupled. The cover of the tractor gearbox is referenced I and the position of a directional control valve "Series 80" is designated by 2. The assembly is adjusted on the cover of the tractor gearbox and the latter is associated with a conventional lever system (not shown) for the gear change.

 The selector valve device comprises a slide valve body 4 which includes a manually operated lever 5 and an inlet for an auxiliary pressure supply. The "Series 80" directional control valve 2 can be one of the valves of a series. of valves arranged side by side and interposed between the speed control block 7 and an outlet end plate "Series 80" 8. However, in the embodiment shown in the drawings, a single control valve 2 is planned. The assembly is fixed by three studs 9 which are of sufficient length to retain the required number of control valves. An outlet 10 is further provided to be connected to the reservoir of an auxiliary hydraulic fluid circuit if such an auxiliary circuit is used.

 The tractor is equipped with a hydraulic circuit comprising a reservoir for the hydraulic fluid which is oil and a pump driven by the tractor engine. This hydraulic circuit is mainly used to actuate hydraulic equipment connected to the rear connection device of the tractor. Referring to Figure 4, we can see in it the orifice which is connected to the input of the rear connection device. By 12 is designated the return port for the hydraulic circuit of the tractor. The inlet orifice which supplies the pressure coming from the tractor hydraulic pump is not specifically shown but communicates with a chamber 13.

 The control lever 5 is coupled to a drawer 14 which, in the position shown, places the chamber 13 in communication with the orifice 11. When the drawer is in this position, the pump of the tractor is connected to the input of the device rear connection and there is no interconnection between the chamber 13 and the orifices 15 which are the inlet orifices of the "Series 80" directional control valves. When the lever 5 is pushed forward to be placed in the position indicated by Sa in FIG. 1, the drawer is moved towards the quarry and cuts the connection between the chamber 13 and the orifice 11. The chamber 13 is then put in communication with the orifices 15. Thus, the inlet pressure is supplied for the tractor pump to the directional control valves. These directional control valves have fittings for connection to any hydraulic device which is to be controlled as auxiliary equipment to the tractor. It will be observed that, since there is the possibility of mounting several valves 2, a corresponding number of auxiliary devices can be controlled simultaneously from the internal pump of the tractor.

 The return fluid from the auxiliary devices is evacuated through the valves 2 in the return channels 16 which are permanently connected to the return orifice 12.

 A particularly important feature of the assembly described with reference to the drawings is that an auxiliary hydraulic circuit independent of the hydraulic circuit of the tractor can be easily connected to supply or provide additional supply to the auxiliary devices through the control valves 2. This can be obtained by providing the auxiliary intake port 6 and the auxiliary discharge port 10 which are connected respectively to the supply and discharge conduits of the auxiliary pumping system under normal conditions, the return port 10 can be closed, the fluid being discharged to the tractor tank through the channels 16 and the auxiliary pump being designed to suck fluid out of the tractor tank. The orifice 10 is provided to allow the installation of a conduit return if necessary, in the event of excessive limitation of the return current through the valve device.

 FIG. 5 shows the schematic diagram of the hydraulic circuit of the system, in which the supply port of the tractor, designated by 17, is coupled, through the slide 14 either to port 11 of the rear connection device, or to the inlet ports 15 of the directional control valve, depending on the position of the drawer. The auxiliary pressure inlet 6 communicates permanently with the orifices 15 and the outlet orifices 16 of the directional control valve are permanently connected to the return orifice 12 of the hydraulic circuit of the tractor. The two positions of the drawer 14 are positively controlled by a connecting rod loaded by a spring and by a pressure reducing member 18.

 If we now refer to Figure 6, we can see an alternative embodiment of the slide valve. The same reference numerals are used to designate the same elements in FIGS. 6 and 5. The main difference which exists between the two embodiments of the slide valve is that, in that represented in FIG. 6, the slide valve can be placed in three separate positions. In FIG. 6, the slide is shown in its central position in which the pressure admission chamber is placed in communication with the inlet orifice 11 of the rear connection device and, at the same time, with the orifices d input 15 of the directional control valves. In this way, the equipment connected to the rear connection device and all the auxiliary devices connected to the directional control valves can be operated simultaneously.

 In this embodiment, a non-return valve comprising a ball 20 housed in an internal bore 21 is incorporated in the drawer.

The ball cooperates with a seat 22 to prevent a return of the fluid from the inlet 11 to the chamber 13 when the drawer is in the position shown.

 When the drawer is moved to the left from its position shown in FIG. 6, the bore 24 is closed by the part 25 of the drawer and the communication between the chamber 13 and the inlet orifices 15 is therefore cut off . Simultaneously, the part 26 of the drawer emerges from the bore 27 and the interconnection between the chamber 13 and the inlet orifice takes place directly, without passing through the ball valve.

 When the drawer is moved to the right from its position shown in FIG. 6, the part 28 of the drawer penetrates into the bore 27, thereby cutting the connection between the chamber 13 and orifice 11. On the other hand, the communication between the chamber 13 and the orifices 15 is maintained.

 The selector valve includes a body molded in the form of a shell and then machined, this body enclosing a hardened and ground control drawer. At each of its ends, the drawer carries an annular seal.

 FIG. 7 is a perspective view of an installation comprising a selector valve device 4a making a connection between the hydraulic circuit of the tractor and two potential auxiliary devices. In the drawings, the connections end with four quick connectors 30. On the selector valve device, two directional control valves "Series 80" 2a, 2b are mounted. The control valves are manually actuated by means of levers 34, 35, by means of flexible connecting cables, the levers 34, 35 replacing the control levers mounted directly on the control valves and shown in FIG. 1 In FIG. 7, the inlet 6 for admitting the auxiliary pressure is shown closed.

 FIG. 8 shows an installation similar to that of FIG. 7, in which however the supply of auxiliary fluid is supplied, through an intake duct 31, by an auxiliary pump (not shown) coupled to the engine of the tractor. A non-return valve 32 is mounted on the conduit 31 which is connected to the inlet orifice 6. A return conduit 33 is connected to the outlet orifice 10 and closes on the auxiliary pump.

Generally, the main pump which normally delivers the fluid has a flow rate of about 27.3 1 / mon, but thanks to the auxiliary pump connected to the system through the inlet of the selector valve, the fluid supply can be carried out generally under a flow of about 59.1 1 / mon. The available hydraulic power is thus considerably increased.

 Note that the selector valve device which has just been described makes it possible to mount side by side a group of directional control valves directly on the casing of the gearbox of a tractor, without the use external piping. The selector valve constitutes both an isolating valve and an interface. The valve allows the tractor's hydraulic circuit to operate simultaneously on several auxiliary devices.

Claims (3)

 1. Device with selector valves for the hydraulic circuit of a tractor used in agriculture, this tractor comprising an auxiliary interface which has a supply orifice (11) connected to the hydraulic pump of the tractor; a return port (12) for the hydraulic fluid; and an inlet port (13) for supplying hydraulic fluid to auxiliary devices, the selector valve device being adapted to be adjusted directly on the interface and comprising orifices which communicate respectively with the orifices (11, 12 and 13), the selector valve device being further adapted to be mounted directly with one or more directional control valves (2) arranged side-by-side and comprising a supply orifice (15) which communicates with a orifice inlet for the directional control valve (s) (2) and a return port (16) which communicates with a return port for the directional control valve (s) (2), the selector valve device still having an orifice auxiliary pressure supply (6) able to be connected to an auxiliary hydraulic pump and a manually actuated slide valve (4) which can be placed in at least a first and a second position, c ette slide valve (4) providing, in its first position, a first interconnection which connects the supply port (13) to the inlet port (11) while in its second position, it cuts the first interconnection and makes a second interconnection between the supply port (13) and the supply port (15), channels being provided in the selector valve device (2) for connecting the supply port with auxiliary pressure (6) to the supply port (15) and to connect the return port (16) to the return port (12).  2. Device according to claim 1, characterized in that a non-return valve is disposed at the inlet port of the auxiliary pressure (6).  3. Device according to claim 1 or 2, characterized in that the slide valve (4) has a third position in which said first and second interconnections are made simultaneously.