GB2151814A

GB2151814A - Remote control device

Info

Publication number: GB2151814A
Application number: GB08431370A
Authority: GB
Inventors: Maurice Tardy
Original assignee: Bennes Marrel SA
Current assignee: Bennes Marrel SA
Priority date: 1983-12-21
Filing date: 1984-12-12
Publication date: 1985-07-24
Also published as: DE3446027A1; FR2557218B1; FR2557218A1; IT1178694B; GB8431370D0; IT8423878A1; SE8406488D0; SE459199B; GB2151814B; JPS60249703A; IT8423878A0; SE8406488L

Abstract

The invention concerns a device for the control of several hydraulic circuits. An oscillating lever (1) operates several control pistons (3) in a control stage (5). Each of these operates one of the pistons (21) of a power stage (6), connected by hydraulic chambers (26) to the operating apparatus. Each control piston (3) forms a hydraulic regulator with transitional surfaces in the shape o fa truncated cone (16, 17) which moves the power stage via an aperture (18, Figure 2, not shown) and axial channel (19) to admit pressure to chamber (20). Applications: multiple hydraulic controls, mainly for civil engineering machines. <IMAGE>

Description

SPECIFICATION A remotely controlled hydraulic emitter with output amplifiers The present invention relates to a remotely controlied hydraulic emitter provided with output am plifying devices.

It is known that in a remotely controlled hydraulic circuit the user operates a lever or a key which causes the desired changes in a hydraulic circuit operating some receiving apparatus. This apparatus is most frequently constituted by hydraulic jacks or motors which may be at a greater or lesser distance from the control position.

The majority of devices known hitherto have various disadvantages, among which are: - the hydraulic output sent to the using apparatus is relatively low, so that the installation has too great a response time; -the control output causes a large calorie input, which leads to excessive heating; - even if it is large, the controlling output is not sufficient to reduce the response time of the installation as much as might be desired; - upon using the regulator, the output affects the characteristic curve of the regulator.

The present invention is intended to avoid these disadvantages, which is of particular value in a hydraulic circuit used to control civil engineering equipment or heavy vehicles.

A remotely controlled hydraulic emitter according to the invention is characterised in that it inciudes at least two stages, namely: - a control stage in which sliding pistons operate according to the known principle of a hydraulic regulator; - a power or amplification stage, in which are used sliding distributor pistons connected to the operating equipment of which they control the variation of the hydraulic power and operative output.

According to another characteristic of the invention, each piston of the controlling regulation stage takes the form of a cylindrical slide valve of which the reduced central portion has the general shape of a diabolo, that is to say the small central section is connected by transitional zones in the shape of truncated cones to the two cylindrical ends of the slide valve.

According to another characteristic of the invention, the central zone of reduced section of a piston has an aperture which communicates with a longitudinal channel located inside this piston and opening at the one of its ends which is directed towards a corresponding piston in the power or amplifying stage.

The attached drawings, given by way of nonlimiting example, will allow the characteristics of the invention to be better understood.

Figure lisa diagrammatic sectional viewofthe assembly of a control position equipped, according to the invention, with two superposed hydraulic stages.

Figures 2 to 4 are longitudinal sections showing the operation of a piston of the control or regulating stage.

Figures 5to 7 are longitudinal section' showing the operation of a piston of the output Dower or amplifying stage.

Figure 8 is a diagram illustrating the operating principle of the regulating stage.

Figure 9 shows the characteristic curve which results from it for the control stage.

There is shown in the drawings a control box of the kinu which is used, for example, on civil engineering machines. At its top this box has an oscillating control lever 1, the base of which is equipped with a thrust plate 2. During movements of the lever 1, the plate 2 comes to depress to a greater or lesser extent one or two movable CO ntrol pistons 3 against their return springs 4.

According to the invention the control pistons 3 slide inside a block which constitutes a control stage 5, whilst below the latter there is located a power stage 6.

The control stage 5 comprises some sliding pistons 3, each one of which operates according to the known principle eta hydraulic regulator. In other words. each piston 3 comprises a reduced section 7 located between two cylindrical portions 8 and 9. It slides in the direction indicated by the double arrow 10 so as to move across three grooves in the stator, namely; - a central control groove 11; - a pressure feed groove 12 connected to the hydraulic feed generator 13; - a return groove 14 connected to the return circuit 15 of the hydraulic installation.

According to the invention, two transitional zones in the shape of a truncated cone 16 and 17 are located between the reduced section 7 and the cylindrical portions 8 and 9 respectively, which ensures a steadily progressive action to the operation ofthe hydraulic regulator.

In addition, the reduced section 7 communicates through an aperture 18 with an axial passage 19 in the piston 3. This axial channel 19 opens into the corresponding part of the power stage 6, namely, more precisely, with the chamber 20 operating the head of a power piston 21. Each power piston 21 slides in the stator of the power stage 6 which comprises: - a groove 22 connected to the hydraulic return circuit 23; - a power feed groove 24 connected to the hydraulic power generator 25; - an end chamber 26 connected directly to the operating circuit, that is to say to the receiving apparatus (motors or jacks) of the installation.

Each power piston 21 slides in cylindrical bearing surfaces which form seals and between which there is a reduced section 27. The latter communicates through an aperture 28 with an axial channel 29 which opens into the operating chamber 26.

The operation is as follows: Each of the control pistons forms with the various bores which separate the grooves 11, 12, 14 chokes which are variable in relation to the displacement of the piston 3. When, by means of the oscillating lever 1,the operator moves a piston 3 against the action of its return spring 4, he puts the corresponding pressure groove 12 into connection with the control groove 11 and the return groove 14.The connection between the feed grooves 12 and control grooves 11 is made through a choke of ?Nit-h the annular section is defined in relation to the position of the transitional cone 16. Si,nilariy, the connection between the return grieve 14 and the control groove 11 is made through a choke cf which the annular section depends on the position of the conical transitionai zone 17.

Thus, there is formed the equivalent or an entry jet 30, of a variable section, between the groove 12 and the chamber 20, and the equivalent of an outlet jet 31, likewise of variable section, between the chamber 20 and the return groove 14. There is thus created a hydraulic regulator of which the diagram- matic representation is given in Figure 8.

Therefore from a supply source 12, 13 of constant pressure there is obtained a control pressure 20 which lies between zero and the nominai value of the feed scarce 12. The variation of this control pressure Pc in relation to the displacement of the control piston 3 (or the angle (x of the lever 1) is shown in Figure 9.

It will be seen that it is possible to obtain for the graph of the Figure 9 any form of curve desired by defining the constructional dimensions and the shapes of the generating curves of the conical portions 16.17.

When the control stage 5 sends the control pressure into the chamber 20 of an operating piston 21, the latter moves and establishes the connection between the pressure groove 24 and the operating chamber 26. This connection is maintained so long as the control pressure Pc in the control chamber 20 is greater than the operating pressure P0 in the operating chamber 26. This connection is maintained so long as P0 (chamber 26) remains greater than Pc (chamber 20).

If P0 tends to be greater than Pc, the piston 21 moves and cuts off the connection between the chambers 24 and 26. If this pressure P0 continues to rise, the piston 21 moves again and establishes the connection between the operating chamber and the return groove 22 until equilibrium between the two pressures P0 and Pc is reestablished.

When the control (stage 5) is released, the piston 3 regains its position of rest and the control pressure in the chamber 20 is removed. Thus the operating piston 21 corresponding regains its rest position (Figure 7), in which the operating pressure in the chamber 26 is removed by being put into communication with the return groove 22.

The device which has just been described gives the following main advantages: - the small output necessary to control the amplifying stage does not disturb the control curve. In addition, it allows considerable reduction in the controlling output of the regulator, therefore in the input of calories; -the amplifying or power stage not being limited in output by chokes, as in the regulator, it allows the passage of a large output, therefore a reduction in the time of response.

Claims

1. A remotely controlled hydraulic emitter comprising at least two stages wherein the first stage is a control stage and the second stage is a power or amplifying stage characterised in that the control stage controls the operation of the power or amplifying stage.

2. A hydraulic emitter according to Claim 1, characterised in that it comprises at least two stages, namely: - a control stage (5), in which sliding pistons (3) operate according to the known principle of a hydraulic regulator, and of which each one has the shape of a cylindrical slide value (8,9), of which the reduced central part has the general shape of a diabolo, that is to say that the small central section (7) is connected by transitional zones (16,17) in the shape of a truncated cone to the two cylindrical ends (8,9) of the slide valve (3); - a power or amplifying stage (6), in which sliding distributing pistons (21) are connected to operating apparatus to which the ensure the variable hydraulic power and operating outputs.

3. A hydraulic emitter according to claim 2, characterised in that the reduced central zone (7) of a piston (3) has an aperture (18) which communicates with a longitudinal channel (19) provided inside this piston (3) so as to open at one of its ends into a control chamber (20) directed towards a corresponding piston (21) of the power or amplifying stage (6).

4. A hydraulic emitter according to claim 3, characterised in that each control piston (3) of the control stage (5) is located in line with an operating piston (21) in the power stage 16), so that the power stage (6) takes the form of a block applied against the block of the control stage (5), at the opposite side to the control lever (1 ! of the assembly.

5. A hydraulic emitter constructed, arranged and adapted to operate substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.