EP1646791B1 - Reversing control device for distributing high-pressure fluid - Google Patents

Abstract

The distributor, consisting of a housing (2) containing a pressure reducer (3), a pusher (5), a distribution channel, a plunger (25), slide valve (30), and return (40) and regulating (50) springs, has a central bore (45) in the pusher that discharges at its lower end (7), with the enlarged head (26) of the plunger moving inside it. The regulating spring is also located inside the pusher bore, between the plunger head and the base of a sleeve (35), so that movement of the pusher causes an expansion of the spring and a reduction in the regulated pressure in output line (22).

Description

The present invention relates to a device for dispensing pressurized fluid used, for example, to control one or more pressurized fluid user systems from a control member, in particular maneuvered by means of a pedal.

In a preferred but not exclusive application, the invention relates to a device for dispensing pressurized fluid installed on board a public works machine.

• un poussoir qui s'étend entre une tête et un pied, qui est monté coulissant au niveau de l'extrémité supérieure du corps, selon un mouvement de va-et-vient entre une position de repos et une position enfoncée, la tête étant sollicitée par l'organe de commande pour permettre la commande d'au moins un récepteur extérieur au dispositif,
• un canal de distribution ménagé dans le corps et qui est en relation à ses extrémités respectivement avec une chambre de compensation principale destinée à être raccordée à un conduite de fluide basse pression et une chambre de compensation auxiliaire borgne, les deux chambres principale et auxiliaire étant en communication au moins temporairement,
• une conduite d'entrée qui débouche dans le canal de distribution, et qui est raccordée à une source de fluide haute pression,
• une conduite de sortie qui débouche dans le canal de distribution et qui est destinée à être raccordée au récepteur à commander,
• un plongeur qui est mobile en translation à l'intérieur de la chambre de compensation et qui comprend une tête élargie ainsi qu'un pied de liaison,
• un tiroir de distribution étagé qui est solidaire en mouvement du plongeur entre une position de début et une position de fin de course pour assurer la fonction de régulation de pression, le tiroir comprenant une première extrémité solidaire du pied de liaison du plongeur en formant un épaulement et une deuxième extrémité libre opposée à la première extrémité et tournée vers la chambre de compensation auxiliaire,
• une coupelle qui est montée coaxiale au plongeur en étant en appui contre le pied du poussoir,
• un ressort de rappel qui est logé dans la chambre de compensation principale, qui est interposé entre la coupelle et le fond de la chambre de compensation principale et qui sollicite élastiquement la coupelle contre le poussoir, et
• un ressort de régulation.

The pressurized fluid dispensing devices usually encountered (for example in the document US Pat. No. 5,251,660) comprise a body which houses at least one pressure reducer and which supports, next to an upper face, a control member that can be modified. the pressure regulated by the pressure reducer, the pressure reducer comprising:

• a pusher which extends between a head and a foot, which is slidably mounted at the upper end of the body, reciprocating between a resting position and a depressed position, the head being urged by the control member to allow the control of at least one receiver external to the device,
• a distribution channel formed in the body and which is connected at its ends respectively with a main compensation chamber intended to be connected to a low-pressure fluid line and a blind auxiliary compensation chamber, the two main and auxiliary chambers being in communication at least temporarily,
• an inlet pipe which opens into the distribution channel and which is connected to a source of high pressure fluid,
• an outlet pipe which opens into the distribution channel and which is intended to be connected to the receiver to be controlled,
• a plunger which is movable in translation inside the compensation chamber and which comprises an enlarged head and a connecting foot,
• a stepped distribution spool which is integral in motion of the plunger between a start position and a limit position for performing the pressure regulating function, the slide comprising a first end secured to the plunger's connecting foot by forming a shoulder and a second free end opposite the first end and facing the auxiliary compensation chamber,
• a cup which is mounted coaxially with the plunger while bearing against the foot of the pusher,
• a return spring which is housed in the main compensation chamber, which is interposed between the cup and the bottom of the main compensation chamber and which elastically urges the cup against the pusher, and
• a control spring.

Such pressurized fluid dispensing devices generally make it possible to increase the regulated pressure in the outlet pipe when the pusher is controlled towards its depressed position.

However, for some applications, it is necessary on the contrary to obtain a lower regulated pressure as the depression of the pusher.

A known solution is to place the regulation on the opposite side to that desired at the control. In the neutral position, the pusher is then fully pressed and the pressure is maximum. In order to cause the decrease in pressure, it controls the raising of the pusher. This device has the disadvantage of not exerting a positive action on the pusher so that it may become stuck in the depressed position. In addition, it is necessary to implement a second pusher that remembers the control member of the first pusher in the neutral position. The size of the device is then increased and the cost is high.

The present invention therefore aims to provide a pressurized fluid dispenser device which reduces the load in the outlet pipe when the pusher is actuated from its rest position to its depressed position.

For this purpose, the device for dispensing pressurized fluid according to the present invention is essentially characterized in that the pusher comprises a central bore which opens at the level of the foot of said pusher, in that the head of the plunger is mounted to move inside. the bore of the pusher, and in that the regulating spring is housed in the central bore of the pusher being interposed between the enlarged head of the plunger and the bottom of the cup, so that the depression of the pusher causes an expansion of the control spring and a decrease the value of the regulated pressure in the outlet pipe.

Thus, thanks to these provisions, the dispensing device according to the present invention implements a single pusher which allows to control a pressure decrease in the outlet pipe by depression of the pusher.

Preferably, the staged drawer comprises a central groove whose annular section increases in the direction of the free end of the drawer.

Advantageously, the slide comprises a central compensation bore which opens at the free end of the slide and which is connected to a transverse bore which opens into the main clearing chamber for at least temporary communication of said two chambers.

Alternatively, a channel external to the drawer is formed in the body to put in communication at least temporarily the two main and auxiliary chambers.

Preferably, the throat of the slide is in permanent connection with the outlet pipe regardless of the axial position of the slide.

• La figure 1 est une vue en coupe longitudinale d'un dispositif distributeur de fluide selon l'invention, aucune pression de fluide ne traversant le réducteur de pression.
• La figure 2 est une vue en coupe transversale du dispositif de la figure 1, une pression étant appliquée et le poussoir étant dans sa position de repos ou non activée.
• La figure 3 est une vue analogue à celle de la figure 2, le poussoir étant commandé vers sa position enfoncée pour provoquer une diminution de pression dans la conduite de sortie.

Various other characteristics of the invention will emerge from the description given below, by way of nonlimiting example, made with reference to the accompanying drawing which illustrates a preferred embodiment of a device for dispensing fluid under pressure.

• Figure 1 is a longitudinal sectional view of a fluid dispensing device according to the invention, no fluid pressure passing through the pressure reducer.
• Figure 2 is a cross-sectional view of the device of Figure 1, a pressure being applied and the pusher being in its rest position or not activated.
• Figure 3 is a view similar to that of Figure 2, the pusher being controlled to its depressed position to cause a decrease in pressure in the outlet pipe.

The pressure fluid dispensing device according to the invention, as shown in FIGS. 1 to 3, and generally designated by the reference numeral 1, comprises a body 2 in which is mounted at less a pressure reducer 3 and which, facing an upper face 4, supports a control member (not shown) able to modify the pressure regulated by the pressure reducer 3.

This pressure reducer 3 has, in a manner known per se, a pusher 5 which extends between a head 6 and a foot 7, and which is slidably mounted at the upper end 4 of the body 2, in a movement of back and forth between a rest position as shown in Figures 1 and 2, and a depressed position as shown in Figure 3. The head 6 is biased by the control member to allow to control at least one organ receiver external to the device (not shown).

Furthermore, a distribution channel 10 is formed in the body 2 and extends between a first end 11 which opens into a main compensation chamber 15, and a second end 12 which opens into a blind auxiliary compensation chamber 16.

In a manner known per se, the main compensation chamber 15 is intended to be connected to a low-pressure fluid line 20 while the auxiliary compensation chamber 16 is blinded by means of, for example, a plug 18.

Furthermore, an inlet pipe 21 opens laterally into the distribution channel 10 and is intended to be connected to a source of high pressure fluid.

Of course, it should be noted that the fluid flowing in the inlet pipe 21 and the fluid flowing in the main and auxiliary compensation chambers 15 are respectively qualified high and low pressure relative to each other, regardless of any absolute value of pressure.

The pressure reducer 3 further comprises an outlet pipe 22 which opens into the distribution channel 10, and which is intended to be connected to the hydraulic receiver to be controlled. The outlet pipe 22 is connected to the distribution channel 10 between the inlet pipe 21 and the auxiliary compensation chamber 16.

Furthermore, the pressure reducer 3 has a plunger 25 integral in displacement of a dispensing spool 30 between a start position of stroke and an end position to provide the pressure regulating function.

The plunger 25 extends between an enlarged head 26 and a connecting foot 27 at which the distribution spool 30 is connected forming a shoulder 28. The plunger 25 is movable in translation inside the main compensation chamber 15.

The dispensing spool 30 has a first end 31 which is integral with the connecting foot 27 of the plunger 25 and a second free end 32 opposite the first end and which is turned towards the auxiliary compensation chamber 16. The dispensing spool 30 and the plunger 25 may for example form a single piece.

In a manner also known per se, a cup 35 is mounted coaxially with the plunger 25 while being in simple support against the foot 7 of the pusher 5.

In order to urge this cup 35 against the foot 7 of the pusher 5, a return spring 40 is housed in the main compensation chamber 15 to be interposed between the cup 35 and the bottom 17 of this main compensation chamber 15. This spring of reminder is coaxial to the cup and is located outside of it.

According to an essential characteristic of the present invention, the pusher 5 is recessed over most of its length and has a central bore 45 which opens at the foot 7 of this pusher. Alternatively, the pusher 5 may be a non-recessed piece which is extended by a hollow cylindrical body forming a liner. This hollow body is functionally similar to the hollow pusher over part of its length. The foot 7 may then for example be integral with the cup instead of being integral with the pusher, the cup thus extending upwards, in the direction of the pusher.

The enlarged head 26 of the plunger 25 is movably mounted inside the central bore 45 of the pusher 5 and is urged towards the bottom of this bore by a regulating spring 50. This regulating spring 50 is housed inside. the bore 45 of the pusher 5 being mounted concentrically to the plunger 25. It is interposed between the underside of the enlarged head 26 of the plunger 25 and the bottom 37 of the cup 35. The plunger 25 thus extends to the Inside the regulating spring 50. In the aforementioned variant, the enlarged head 26 is movably mounted inside the hollow body which acts as a jacket for this head. The provision of a hollow pusher advantageously allows a saving of space.

Furthermore, the distribution spool 30 has on the one hand, an axial central bore 33 which opens at the free end 32 of this drawer to be connected to the auxiliary compensation chamber 16 and secondly, a transverse bore 34 which opens into the main compensation chamber 15 and which is connected to the axial bore 33. At the free end 32 of the 30, the central bore 33 may be provided with a restriction 42 which opens into the auxiliary chamber 16. The axial bores 33 and 34 transverse allow to put in permanent communication the two main compensation chamber 15 and auxiliary 16.

As a variant, this permanent communication is obtained by replacing the two bores 33 and 34 with a channel 43 external to the drawer, being formed in the body 2 of the device 1. This channel 43 is represented in FIGS. 1 to 3 in dashed lines .

According to another essential characteristic of the present invention, the compensation slide 30 has, in its central part, a groove 37 whose annular section increases in the direction of the free end 32 of the slide 30. This central groove 37 defines on the surface exterior of the spool 30 an upstream annular shoulder 38 and a downstream annular shoulder 39 which extend substantially transversely to the longitudinal axis of the spool. The surface of the upstream shoulder 38 is smaller than the surface of the downstream shoulder 39 so that the increase of the pressure in the inlet pipe 21 causes the slide 30 to move towards the auxiliary compensation chamber 16 .

The central groove 37 is, regardless of the position of the distribution spool 30 inside the distribution channel 10, in permanent connection with the outlet pipe 22.

Thus, when no pressure is sent into the pressure reducer 3, as shown in Figure 1, the return spring 45 pushes up the cup 35 while the control spring 50 which is a spring of compression both to spread the enlarged head 26 relative to the bottom 37 of the cup 35. The drawer 30 is in high abutment against the cup by pressing the shoulder 28 on the bottom of the cup, outside thereof .

When fluid under pressure passes through the inlet pipe 21 (FIG. 2), the slide 30 is in equilibrium under the action of the differential pressure which is exerted in the central groove 37 on the one hand and under the action of the control spring 50 on the other hand.

The drawer 30 is then in an equilibrium position in which it is no longer in abutment against the bottom of the cup, the shoulder 28 of this drawer having been removed from this bottom.

A so-called high pressure is then exerted in the outlet pipe 22. When it is desired to reduce this pressure exiting through the pipe 22, it is sufficient to control the depression of the pusher 5 by pressing on its head 6 (FIG. 3), this movement causes the compression spring 50 to relax.

The slide 30 can then again be in abutment against the bottom of the cup, by its shoulder 28.

The pressurized fluid dispenser according to the present invention thus enables the fluid pressure to be controlled in the outlet line 22 from a high value when the pusher is not depressed to a lower position when this pusher is pressed inside. of the clearing house. The pressure regulation will thus be considered as inverted. The regulating spring gives the spool valve a set point from bottom to top.

The invention is of course not limited to the example described above and various modifications can be made without departing from its scope.

Claims (5)

1. Pressurised-fluid distributing device comprising a body (2) which houses at least one pressure reducer (3) and carries, opposite an upper face (4), a control component suitable for modifying the pressure regulated by the pressure reducer (3), said pressure reducer (3) having:

   - a push-rod (5) which extends between a head (6) and a foot (7), which is mounted so as to slide, at the upper end (4) of the body (2), in a to-and-fro movement between a rest position and a driven-in position, said head (6) being impelled by the control component in order to permit the control of at least one driven part external to the device;

   - a distributing duct (10) which is arranged in the body and is in communication at its ends (11, 12) with, respectively, a main compensating chamber (15) intended for connection to a conduit (20) for low-pressure fluid and a blind auxiliary compensating chamber (16), the two main and auxiliary chambers being in communication, at least temporarily;

   - an inlet conduit (21) which emerges into the distributing duct (10) and which is connected to a source of high-pressure fluid;

   - an outlet conduit (22) which emerges into the distributing duct (10) and is intended for connection to the driven part to be controlled;

   - a plunger (25) which is movable in translation inside the compensating chamber and which comprises an enlarged head (26) and also a linking foot (27);

   - a tiered distributing slide (30) which is integral in motion with the plunger (25) between a start-of-travel position and an end-of-travel position in order to perform the pressure-regulating function, said slide (30) comprising a first end (31) which is integral with the linking foot (27) of the plunger (25), thereby forming a shoulder (28), and a second, free end (32) which is opposed to the first end (31) and faces towards the auxiliary compensating chamber (16) ;

   - an obturator ring (35) which is mounted so as to be coaxial with the plunger (25) while resting against the foot (7) of the push-rod (5);

   - a return spring (40) which is housed in the main compensating chamber (15), is interposed between the obturator ring (35) and the bottom (17) of said main compensating chamber (15), and impels said obturator ring (35) elastically against the push-rod (5); and

   - a regulating spring (50);

   characterised in that the push-rod (5) comprises a central bore (45) which emerges at the foot (7) of the said push-rod (5),
   in that the enlarged head (26) of the plunger (25) is mounted in a movable manner inside the bore (45) in the push-rod (5), and
   in that the regulating spring (50) is housed in the central bore (45) in the push-rod (5) while being interposed between the enlarged head (26) of the plunger (25) and the bottom (36) of the obturator ring (35), in such a way that the driving-in of the push-rod (25) brings about an expansion of the regulating spring (50) and a reduction in the value of the regulated pressure in the outlet conduit (22).
2. Device according to Claim 1, characterised in that the tiered slide (30) comprises a central channel (37) whose annular section increases in the direction of the free end (32) of said slide (30).
3. Device according to Claim 2, characterised in that the slide (30) comprises a central compensating bore (33) which emerges at the free end (32) of said slide and is connected to a transverse bore (34) which emerges into the main compensating chamber (15) for the purpose of bringing the said two chambers into at least temporary communication.
4. Device according to Claim 2, characterised in that a duct (43) external to the slide (30) is arranged in the body (2) in order to bring the two main (15) and auxiliary (16) chambers into communication, at least temporarily.
5. Device according to any of Claims 2 to 4, characterised in that the channel (37) in the slide (30) is permanently linked with the outlet conduit (22), whatever the axial position of said slide (30).

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