GB2052642A

GB2052642A - A Machine Provided With a Device for the Passage of Hydraulic Fluid to and From and Remote Control of a Plurality of Hydraulic Receivers Arranged on the Machine

Info

Publication number: GB2052642A
Application number: GB8017978A
Authority: GB
Original assignee: SECOMA
Current assignee: SECOMA
Priority date: 1979-06-25
Filing date: 1980-06-02
Publication date: 1981-01-28
Also published as: CH635886A5; FR2459895B1; AU536808B2; AU5956480A; SE8004263L; FR2459895A1; GB2052642B; DE3022134A1; ZA803366B; JPS5620296A

Abstract

A mining or excavating machine has a plurality of hydraulic receivers, such as hydraulic jacks or hydraulic motors, associated with a respective electrically operated valves 21 each controlling the supply of hydraulic fluid to and the return of the fluid from the corresponding hydraulic receiver. All the valves are connected to a common hydraulic fluid supply pipe 22 and a common return pipe 23. A common conductor 20 connected to all the valves conveys coded signals thereto. Each valve has a decoding circuit so that on receiving a particular signal designating actuation of the hydraulic receiver corresponding to that valve is operated to cause the desired actuation. The instructions for actuation of a particular hydraulic receiver can be converted to code in a remote control box 17 having a coder sending a coded electrical signal output by cable 18 to a receiver- analyser 19 connected to the conductor 20. Or the remote control can utilize a radio link in which a remote control box 24 having a coder emits coded radio signals picked up by a receiver 25 in which the signals are amplified and sent by cable to the receiver-analyser. <IMAGE>

Description

SPECIFICATION A Machine Provided with a Device for the Passage of Hydraulic Fluid To and From and Remote Control of a Plurality of Hydraulic Receivers Arranged on the Machine This invention relates to a machine provided with a device for the passage of hydraulic fluid to and from and remote control of a plurality of hydraulic receivers arranged on the machine.

The hydraulic receivers may be hydraulic actuators or jacks, hydraulic motors or impact mechanisms.

The machines may be for use in mining or for public works; In machines of this kind, for example, boring equipment and hydraulic shovels, the feed to the different hydraulic receivers, which are generally camed by the same articulated arm, is achieved by a set of flexible pipes; For each receiver there are two-flexible hydraulic pipes, one for supply and the other for return of the hydraulic fluid, so arranged that on machines with a large number of receivers, it is necessary to provide a large number of flexible pipes in a cluster.

A diagrammatic example of a known machine is shown in Fig. I of the accompanying drawings, -having a boring slide rod 1 which carries several receivers, such as hydraulic actuators 2,3,4 and a hydraulic motor 5. Each receiver is connected by two flexible oipe-s-;-6, 7 to a :orreSpoirding hydraulic distributor 8, which is placed on a body of the boring equipment. The receivers are generally arranged-in several groups, corresponding to several groups Of distributors 8 whose supply is achieved by means of separate pumps. In the example shown in Fig. 1, two groups of distributors are supplied by two pumps 9 and 10 respectively.A common return pipe 11 connects all the distributors to a reservoir. It is understood that the hydraulic connectionbetween the body of the equipment and the slide rod 1 (a connection which shown diagrammatically by a single line in 12) consists of a cluster of 2n hydraulic flexible pipes, where n represents the total number of receivers (without counting any flexible pipes which may be used for the return of-leakages to the reservoir).

This cluster of flexible pipes constitutes a drawback in the utilisation of the machine,-since the flexible pipes are subject to torsion, to becoming hooked up, to wear, to ruptures, and breakdowns in operation are more frequent the more numerous the flexible pipes.

As additional drawbacks the numerous flexible pipes have considerable weight and occupy -considerable space, as well as being costly; Furthermore, the large volume occupied by the flexible pipes makes access to certain elements of the machine difficult.

In a case which the distributors 8 are not controlled directly manually, it is already known to provide electricqremote control of the distributors by cable. This remote control comprises a remote control box 13 connected bymeans of a multi conductor cable 14 to a terminal box 1 5 which is itself connected by wire 1 6 to electromagnets of the different distributors 8.

An object of the invention is to provide a machine with a device for the passage of hydraulic fluid-to and from and the remote control of a plurality of hydraulic receivers in which a large number of flexible hydraulic pipes is no longer required, so that the drawbacks mentioned above will be eliminated or at least mitigated, whilst being compatible with centralised remote control by electrical means.

According to the invention there is provided a machine provided with a device for the passage of hydraulic fluid to and from and remote control of a plurality of hydraulic receivers arranged on the machine; the device comprising a plurality of electrically operated hydraulic valves provided on the machine, each valve corresponding to a respective said receiver and disposed in the vicinity of the receiver or combined with said receiver, the passage of hydraulic fluid to and from the receivers being through only two hydraulic lines common to said receivers, one said line being the feed and the other said line being the return, both said lines passing through the valves, and all said valves being remotely controlled by means of a common electric cable comprising a single conductor or a multiple conductor which terminates at the different valves.

By virtue of branching the electrically operated valves into two common hydraulic pipes, it is possible, compared-with known machines, to reduce considerably the number of hydraulic connections or flexible pipes since this number is reduced to two whatever the total number of hydraulic receivers. The simplification obtained in this manner can greatly reduce the frequency of operational accidents (hooking up, ruptures, etc.) and reduces the weight and volume of the hydraulic connections, and hence makes possible both a reduction in their cost and better accessibility to elements of the machine which makes machine maintenance easier.

Another advantage is the reduction of the response time of-the hydraulic receivers to a command. The electrically operated valves, since they are arranged in the vicinity of the hydraulic receivers and are branched in the hydraulic feed line which can be permanently under pressure, cause an immediate operation of the corresponding receivers when the valves are actuated. In the known machines there is a delay in the operation of the hydraulic receivers due to the time needed to raise the pressure in the corresponding feed pipes to the working value. In the machine formed according to the invention it is possible to have only a single supply pump suppiying pressurised flu-id to the feed line.

The electrically operatedvalves -branched into the t-wo hydraulic lines can be combined with a remote:confrol:ofthe kind in Fig. 1, that is, with a set of electric wires, sudh as the wires 1 6, which '-terminate at the different electrically operated valves which are hence controlled in an independent manner. In a case in which the machine is used in a normal atmosphere, the electrical connection with the different electrically operated valves can be quite easily achieved by means of a multi-conductor cable, which groups together all the wires, whilst the dimensions on this cable become great if the number of hydraulic receivers to be supplied is high.

In the case of a machine which operates in an explosive atmosphere, which is sometimes the case for mining machinery, the control of the valves using respective independent conductors is not always suitable. The use of a multi-conductor cable remains a possible opinion if a low level of electrical power is used which is compatible with standards relating to intrinsic safety, and in this case operation of the valves may be assisted by hydraulic pressure. On the other hand, if intrinsic safety cannot be guaranteed, the individual conductors must be in separate cables and results in the provision of a cluster of cables.Thus, whilst the cluster of hydraulic flexible pipes which exist in the previously known machines has been eliminated, there would instead be a cluster of electrical cables which would take up space and obviously would be exposed to the same risk of torsion, hooking up, etc., and practically no advantage would be gained from this substitution.

In the known remote control circuit shown in Fig. 1 the multi-conductor cable 14 which connects the remote control box 13 to the terminal box 15, is of considerable size and hence of considerable weight when the number of hydraulic receivers to be controlled is great. In this case, the operator who carries the box has difficulties in moving it.

In order to eliminate these drawbacks, means are provided, in one embodiment of the invention, which are situated at a distance from the hydraulic receivers and are able to convert commands for the different hydraulic receivers into coded signals transmitted on a common single or multiple electrical conductor which terminates in all the electrically operated valves.

Each valve is associated with a signal de-coding circuit, which is able to excite a coil of the valve only on the transmission of a signal which designates the hydraulic receiver which corresponds to that valve.

By using this system of commands for the hydraulic receivers, it is possible to use the machine in an explosive atmosphere in good safety conditions without this involving a complicated set of electric cables. The choice of a coding system can also eliminate the necessity for a multi-conductor cable terminating at the remote control box.

In a first case a remote control box may be provided with a coder connected by a cable to a receiver-signal analyser, whence the common electrical conductor starts which passes through all the electrically operated valves provided in the vicinity of the corresponding hydraulic receivers.

The machine may also be remotely controlled by radio.

In this second case, a box for remote control by radio may be provided having a coder and a radio signal emitter. An associated receiver of radio signals may be provided in a receiver-amplifier of signals connected by a cable to a receiveranalyser of signals from whence starts the common electrical conductor which passes through all the electrically operated valves provided in the vicinity of the corresponding hydraulic receivers.

In both cases; the remote control box includes a code generator which transposes the commands for the different hydraulic receivers into coded signals, which after shaping and amplification by the receiver-analyser of signals, are transmitted by a single or multiple conductor, but always a common one, to each electrically operated hydraulic valve. Of course it is also possible to supply the coils of the different valves with electric power. This can be achieved by one or several separate cables, but preferably a single cable is connected with all the electrical operated valves this cable containing on the one hand electrical conductors for the power supply of the coils of the valves, and, on the other hand, the abovementioned common conductor which transmits the coded signals, this conductor being surrounded by a metal sheathing.When the machine is intended to operate in an explosive atmosphere, the set of conductors of the abovementioned connecting cable can be armoured.

The invention will now be further described, by way of example, with reference to the accompanying drawings in which: Fig. 2 is a diagrammatic representation of a device (and possible modification thereof) for the passage of hydraulic fluid to and from and remote control of hydraulic receivers in a machine formed according to the invention; Fig. 3 shows diagrammatically a fragment of an embodiment of a machine formed according to the invention and having a boring slide rod, said machine including the device in Fig. 2; Figs. 4 and 5 are cross sectional views of cables which may be used in a machine formed according to the invention, and Fig. 6 is a diagrammatic view of an electrically operated valve associated with a said receiver for a machine formed according to the invention.

As shown in Fig. 2, the device includes, for its "remote control", a remote control box 17 connected by a cable 1 8 to a receiver-analyser of signals 19, which is itself connected by another electric cable 20 to a number of electrically operated valves 21. Each electrically operated valve21 is provided on the corresponding hydraulic receiver (not shown).

The remote control box 17 is provided with a coder which transforms commands for the different hydraulic receivers into coded signals which are transmitted by the cable 18 to the receiver-analyser 19. The functions of the receiver-analyser 19 are: the shaping and amplification of the signals before they are sent to the electrically operated valves 21; an operational logical function containing security checks and necessary prohibitions; possible programming of automatic sequences.

Each electrically operated valve 21 includes a circuit for decoding signals transmitted on the cable 20, this circuit operating in such a manner as to excite a coil of the electrically operated valve only on the transmission of a signal which designates the hydraulic receiver associated with that valve.

Two hydraulic pipes 22 and 23, one for supply and the other for return, are connected to all the hydraulic receivers, the electrically operated valves 21 all being branched in the pipes 22 and 23.

In a possible modification, the remote control box 1 7 with the coder, which is connected by a cable 1 8 to the receiver-analyser 19, can be replaced by a radio remote control box 24 which stili has the same function of coding command orders for different receivers. This remote control box 24 combines a radio signal emitter and a coder, and is associated with a radio receiver and amplifier of signals 25 which is connected by a cable 26 to the receiver-analyser of signals 1 9.

Fig. 3 shows how the principle of the device in Fig. 2 is applicable to a boring slide rod 1 which is provided on an articulated arm (not shown) and which, as is already described with reference to Fig. 1, carries various hydraulic receivers, for example the actuators indicated at 2, 3 and 4 and the hydraulic motor 5.

From the hydraulic point of view, an electrically operated valve 21 is mounted directly on each hydraulic receiver 2, 3, 4 and 5, and all these valves are supplied by two common hydraulic pipes 22 and 23 which connect the body of the machine to the slider 1. A single pump 27 supplies the supply pipe 22.

From the electrical point of view, the device of Fig. 3 has a remote control by cable 1 8 starting from the box 17, the receiver-analyser of signals 19 being connected by a single cable 20 to all the electrically operated valves 21 on the hydraulic receivers.

The result of this is that the connection between the body of the machine and the slide rod 1, a connection which is shown diagrammatically at 28, includes in practice only two flexible hydraulic pipes, which correspond to the pipes 22 and 23, and a single cable 20. The number of flexible hydraulic pipes is consequently very greatly reduced in comparison with the known machine in Fig. 1. In addition it will be observed that this reduction of the number of flexible pipes has not caused a considerable increase in the cross section of the flexible pipes 22 and 23, for in practice only one of the hydraulic receivers is supplied with hydraulic fluid at any given time so the amount of hydraulic fluid which is conveyed in unit time by the pipes 22 and 23 is not perceptibly increased over that conveyed by any pair of pipes 6 and 7 in the cluster 12 (Fig. 1).

The cable 20 for connection with the electrically operated valves 21 has a more special structure, as shown in Fig. 4 or 5. This cable includes conductors 29 and 30, which are for the power supply to the coils of the electrically operated valves, and a conductor 31 which transmits the coded signals. In Figs. 4 and 5, the conductor 31 is a single conductor.

In the case of a machine which operates in a normal atmosphere, the cross section of the cable 20 can be that shown in Fig. 4: the supply conductors 29 and 30 are simply embedded in the insulating material of the cable, and only the conductor 31 for transmission of signals is surrounded by a sheath 32 which is necessary to avoid possible interference.

In the case of a machine which operates in an explosive atmosphere, the cross section of the cable 20 is preferably that shown in Fig. 5 in which not only is the transmission conductor 31 surrounded by a metal sheath 32, but also the set of three conductors 29, 30 and 31 is surrounded by armour 33 which is used to guard the cable. It should be noted that for intrinsic safety the provision of the remote control box 1 7 (or 24) is advantageous as in an explosion-proof housing for the receiver-analyser 19 (also possibly for the receiver-ampiifier 25), as well as explosion-proof boxes for the electrical parts of each electrically operated valve 21, with explosion-proof stuffing boxes for the different cable outlets.

Finally Fig. 6 shows one of the electrically operated valves 21 mounted on a hydraulic receiver 2, 3 or 4 which is shown as being an actuator or jack. As already indicated above, the electrically operated valve 21 is inserted in the two hydraulic pipes 22 and 23 and in the electric cable 20. The electrically operated valve in Fig. 6 includes a signal decoder 34 associated with a relay for control of the coil of the valve.

The cross sections of the cable 20, as shown in Figs. 4 and 5, are given purely as examples and can be subject to modification, on the one hand in relation to the standards in force according to the country, and, on the other hand, in relation to the selected coding system. The single conductor 31, the purpose of which is to convey a code provided by a succession of unit signals, can be replaced by a multiple conductor for the sending of a code formed of simultaneous unit signals transmitted in parallel and taken in combination designate the particular hydraulic receiver.

The invention can be applied to machines operating in the following fields: machines used in mining, machines for public works, handling machines with hydraulic receivers a greater or lesser number which can be actuators or jacks, hydraulic motors or impact mechanisms.

The electrically operated valves 21 , which it is assumed are mounted on the corresponding hydraulic receivers in the described examples, can also be combined with the receivers by forming these of appropriate design.

Claims

1. A machine provided with a device for the passage of hydraulic fluid to and from and remote control of a plurality of hydraulic receivers arranged on the machine, the device comprising a plurality of electrically operated hydraulic valves provided on the machine, each valve corresponding to a respective said receiver and disposed in the vicinity of the receiver or combined with said receiver, the passage of hydraulic fluid to and from the receivers being through only two hydraulic lines common to said receivers, one said line being the feed and the other said line being the return, both said lines passing through the valves, and all said valves being remotely controlled by means of a common electric cable comprising a single conductor or a multiple conductor which terminates at the different valves.

2. A machine provided with a device as claimed in claim 1, in which at a distance from the hydraulic receivers, suitable means are provided for converting the commands for the different hydraulic receivers into coded signals, said signals are transmitted on a common electrical conductor which is single or multiple terminating at all the electrically operated valves, each valve is associated with a circuit for decoding signals, and a said circuit is able to excite a coil of the corresponding electrically operated valve only on transmission of a signal which designates the hydraulic receiver corresponding to that valve.

3. A machine provided with a device as claimed in claim 2, in which a remote control box with a coder is connected by a second cable to a receiver-analyser of signals from whence departs the common electrical conductor which passes through all the electrically operated valves.

4. A machine provided with a device as claimed in claim 2, further comprising a radio remote control box with a coder and an emitter of radio signals, an associated radio signal receiveramplifier of signals connected by a second cable to a receiver-analyser of signals from whence departs the common electric conductor which passes through all the electrically operated valves.

5. A machine provided with a device as claimed in any one of claims 2 to 4, in which the first mentioned cable has a single connection to, all the electrically operated valves and said first cable contains additional electrical conductors for supplying power to the coils of the electrically operated valves and the first mentioned conductor which is single or multiple and transmits decoded signals, said first conductor being surrounded by a metal sheathing.

6. A machine provided with a device as claimed in claim 5, the set of first and additional conductors is surrounded by armour.

7. A machine provided with a device as claimed in any one of ciaims 1 to 6, said machine having a boring slide rod on an articulated arm, said slide rod carrying a plurality of said hydraulic receivers, said electrically operated valve being mounted on each receiver or combined with the receiver and the hydraulic connection between a body of the machine and the slide rod consisting only of two flexible pipes comprising the two hydraulic lines.

8. A machine provided with a device for the passage of hydraulic fluid to and from and remote control of a plurality of hydraulic receivers arranged on the machine, substantiålly as hereinbefore described with reference to Figs. 2 to 6 of the accompanying drawings.