EP0117806A1 - Fluid distribution device, particularly for a remote control - Google Patents

Abstract

The fluid distributing device, more especially for remote control, comprises a body (2) having bores (3) with parallel axes in which are slidably mounted slide valves (4) associated in pairs and controlled by push-rods (5) actuated by an oscillating cam (6). Each slide valve bore (3) has a groove (8) connected to the pressurized fluid intake, each slide valve being combined with a chamber (9) limited by at least one transverse annular surface (b) of the slide valve and connected to the reservoir by a constriction. It comprises return devices (R) for each push-rod (5) adapted to maintain a first push-rod in abutment against the cam (6) when this latter tends to move away from the push-rod and each slide valve comprises, on its periphery, towards its end (15) remote from the push-rod, a recess (g) whose arrangement and length are such that before the end of the complete movement of the slide valve (4) when it is driven by the first push-rod, the recess establishes a connection between the pressurized fluid intake (8, P) and the chamber (9), the whole being such that there is a rise in pressure of the fluid in this chamber (9) which causes locking of the slide valve (4) and of the first push-rod (5) in the high position.

Description

The invention relates to a fluid dispensing device, in particular for a remote control, of the type which includes a body provided with bores with parallel axes in which are mounted sliding drawers associated two by two, in particular symmetrically with respect to the 'axis of the body, these drawers being controlled by pushers actuated by an oscillating cam or the like to establish the desired communications between an inlet of pressurized fluid, a reservoir of fluid at low pressure, and a starting orifice towards a member of use, each spool bore having a groove connected to the arrival of pressurized fluid, each slide valve being combined with a chamber limited by at least one annular surface of trans _- versale of the drawer and connected to the tank via a throttle.

The invention relates more particularly, but not exclusively, the dispensing devices of this kind used on _s public works vehicles.

It is known to arrange a fluid distributor of the kind in question so that the control can be immobilized in a working position determined in advance for a given function. Such locking allows the user of the fluid distributor device to release the lever acting on the oscillating cam, without the function being interrupted; meanwhile, the u _- ser may do any other operation.

Such a fluid dispensing device is known for example from patent application DE 32 16 659. However, this known device has the disadvantage that, by reason of its arrangement, the pusher which is located opposite the part of the cam which tends to move away is not subjected to an upward force capable of move it in contact with the cam only when the cam has been brought in and kept in an extreme inclination causing the maximum depression of another push rod opposite to the previous one. This abrupt abutment of the first push button named against the cam generates shocks likely to annoy the user and damage the apparatus in the long run.

In addition, such an arrangement makes two opposite pushers slaved to each other since the hydraulic pressure necessary for the upward movement of one is supplied following the downward movement of the other. As a result, the reliability and security of the device are not optimal.

Finally, the arrangement in question requires the machining of numerous connecting channels, which singularly complicates the structure and increases the manufacturing cost.

The object of the invention is essentially to remedy these drawbacks as far as possible and to propose a dispensing device which gives better satisfaction to the various requirements of the practice, and which, in particular, is of a smoother operation, which either more reliable and safer and which is of a simpler and less costly structure to manufacture.

According to the invention, a fluid dispensing device of the kind defined above, is characterized in that it comprises means for returning each pusher suitable for maintaining a first pusher in permanent support against the cam when the latter tends to move away from said pusher during the driving-in movement of a second associated pusher, the drawer corresponding to the first pusher being driven by the latter in its movement, and by the fact that each drawer has, on its periphery, towards its end distant of the pusher, a recess whose arrangement and length are such that before the end of the complete movement of the drawer during its drive by the first pusher, said recess establishes a connection between the inlet of pressurized fluid and the said chamber, the assembly being such that there is a rise in pressure of the fluid in this chamber which ensures the locking of the drawer and of the first pusher in the high position and, consequently, the locking of the other pusher and of the corresponding drawer in position low.

The return means of each pusher may comprise elastic return means, in particular formed by a spring bearing at one end against the body, and at the other end against the pusher, abutment surfaces being provided between the pusher and the drawer to allow the drawer to be driven by the pusher.

The recess provided at the periphery of the drawer can be formed by a peripheral clearance forming an annular groove.

The drawer can be a regulation drawer, the insertion of which is controlled, from the pusher, by means of a setting spring so that the pressure of the fluid, at the outlet orifice, can be adjusted. In this case, advantageously, the starting orifice is provided in the axis of the bore of the regulating slide, which comprises an axial channel opening at one end towards said starting orifice, the aforesaid. chamber being provided in the body of the distributor and being located in the direction of the axis of the bore between the zone of this bore where the axial channel opens and the groove connected to the pressure inlet.

The drawer can be a simple dispensing drawer directly controlled by the pusher; the chamber is then provided, in the distributor body, at the end of the drawer opposite the pusher.

Advantageously, all the fluid pressure inlet, return to the reservoir, and departure orifices can be provided on the same face of the distributor, generally the face opposite to that adjacent to the cam.

The locking is provided in such a way that it is possible for the user to overcome the locking effort in the event of an emergency or safety stop, by acting on the normal control and exerting a reasonable effort.

It is also possible to provide automatic control of the unlocking, for example when a movement is finished, using a limit switch contact.

This unlocking command can be carried out by establishing a connection, in particular by means of an electrovalve, between the chambers corresponding to two associated drawers.

• La figure 1, de ces dessins, est une représentation simplifiée d'un dispositif distributeur conforme à l'invention comportant des tiroirs de régulation.
• La figure 2 représente une variante du distributeur de la figure 1.
• La figure 3 est une représentation schématique partielle d'un distributeur selon l'invention comportant des tiroirs de distribution.
• La figure 4, enfin, est une vue simplifiée de dessous par rapport à la figure l montrant le système de déverrouillage automatique.

The invention will be better understood with the aid of the following description of particular but non-limiting embodiments shown in the accompanying drawings.

• Figure 1 of these drawings is a simplified representation of a dispensing device according to the invention comprising control drawers.
• FIG. 2 represents a variant of the dispenser of FIG. 1.
• Figure 3 is a partial schematic representation of a dispenser according to the invention comprising distribution drawers.
• Figure 4, finally, is a simplified view from below compared to Figure l showing the automatic unlocking system.

Referring to Figure 1, we can see a fluid distributor device 1 formed by a hydraulic manipulator, in particular for remote control. This device comprises a body 2 provided with bores 3 with parallel axes in which are mounted drawers 4 associated two by two, symmetrically with respect to the axis A-A of the body. Generally two or four slots, as well as two or four corresponding drawers are provided in the body 2, diametrically opposite two by two.

Each drawer 4 is controlled by a pusher 5 actuated by an oscillating cam 6 or the like. The cam 6 forms a sort of plate fixed to a control lever 7 articulated around the point O. Each slide 4 is suitable for establishing, by moving in the bore 3, the desired communications between an inlet for pressurized fluid P located in the body 2, a low-pressure fluid reservoir (not shown) connected to the areas designated by T and a starting orifice D, corresponding to each bore 3, towards a user member (not shown) such as a hydraulic cylinder .

Each bore 3 has an annular groove 8 connected to the pressurized fluid inlet P. Each drawer 3 is combined with a chamber 9 limited by at least one annular transverse surface b of the drawers. This chamber 9 is connected to a pipe 10 leading to the reservoir via a throttle e advantageously formed by a nozzle 11 with calibrated nozzle mounted in a pipe 12 connecting the chamber 9 to the pipe 10.

In the embodiment of FIG. 1, each drawer 4 is a regulation drawer whose insertion, in the bore 3 is controlled from the pusher 5 by means of a calibration spring 13.

In the solution represented in FIG. 1, the outlet or departure orifice D associated with the bore 3 is provided in the axis of this bore; the drawer 4 has an axial channel 14 opening at its end 15 facing the orifice D. Radial channels, 16, 17 are provided in appropriate places, in the axial direction, to establish the desired connections during the movement of the drawer 4 .

The end 15, when the drawer 4 is pushed in, comes into contact with a washer 18 in abutment center the conps 2 and pushes this washer against a spring 19 housed in a cylindrical space 20 communicating axially with the orifice starting point D and provided towards said end 15.

The end zone 15 of the drawer 4 has a smaller diameter f than that of the bore 3 (the diameter of the bore 3 is, apart from the operating clearance, that of the major part of the drawer 4 ). The transverse annular surface b is formed by the shoulder marking the transition between the end zone 15 and the rest of the drawer. The chamber 9 is provided in the body of the distributor and is located, in the direction of the axis of the bore, between the zone 21 of this bore where the axial channel 14 opens, and the groove 8 connected to the inlet of pressure P.

The dispensing device 1 comprises return means R of each pusher 5 suitable for maintaining a first pusher against the cam 6 when the latter tends to move away from said pusher during the driving-in movement of a second diametrically opposite pusher. According to the representation of FIG. 1, this means that the first pusher 5 is held in abutment against the cam 6 when the region of the latter, in abutment against the pusher, moves upwards.

These return means R advantageously comprise elastic return means formed by a spring 22 bearing, at one end, against the body 2 and, at its other end, against the pusher 5, in particular by means of a cup 23. Stop surfaces 24, 25 are provided between the pusher 5 and the drawer 4 to allow the drawer to be driven, by the pusher 5 under the action of the spring 23, in an upward movement according to the representation in FIG. 1. More specifically, the abutment surface 24 of the pusher 5 is obtained at using two semi-washers separated according to a diameter, inserted between the cup 23 and the base of the pusher 5. The abutment surface 25 is formed by a transverse shoulder of the head 25a of a plunger 26 secured to the drawer 4. The head 25a is located in a blind bore 27 of the pusher 5, the axial length of this blind bore 27 allowing a movement, upwards relative to the pusher, of the head 25a. The cup 23 and the pusher 5 slide in a bore 28 provided in an upper part 2a, attached, of the distributor body. The bore 28 is closed by a plug 29, screwed into the threaded end of the bore 28, and the internal transverse face 29a of which serves as a limit stop for the pusher 5.

Each drawer 4 has, on its periphery, towards its end 15 remote from the pusher, a cavity advantageously constituted by a peripheral recess forming an annular groove 30 situated between the end zone 15 of the drawer 4, and the rest of the drawer.

The arrangement of this groove 30 along the axis of the drawer 4, and its length are such that before the end of the complete displacement of the drawer 4 during its drive (upwards according to the representation of FIG. 1) by the pusher 5 , said recess or groove 30 establishes a connection between the groove 8 for the arrival of pressurized fluid and the chamber 9. As a result there is an increase in fluid pressure in this chamber, which ensures the hydraulic locking of the drawer 4 and of the pusher 5 in the high position and consequently the locking of the pusher and of the corresponding diametrically opposite drawer in the low position.

The abutment surface 29a of the plug 29 is located so that the pusher 5 can travel long enough for the groove 30 to come into communication with the groove 8.

The permanent flow which is established through the nozzle 11 creates a pressure drop ensuring the maintenance of sufficient pressure in the chamber 9 for hydraulic locking.

This locking is provided in such a way that it is possible for the user to overcome the hydraulic locking effort in the event of an emergency stop or for safety reasons by exerting a reasonable effort on the lever 7.

An automatic unlocking control can be provided for example when a lifting movement controlled by the operating member (not shown) connected to the starting orifice D is completed.

As can be seen in FIG. 4, this unlocking command comprises a set 31 of connecting pipes between the two chambers 9 of the diametrically opposite drawers 4. The passage of the fluid in this pipe assembly 31 is controlled by a solenoid valve 32 whose drawer 33 is housed in a pipe section of the assembly 31. When the communication between the two diametrically opposed chambers 9 is cut by the drawer 33 , the hydraulic locking can take place. When the communication between the two opposite chambers 9 is established by the drawer 33, there is pressure equalization in the chambers and unlocking, in particular because the spring 19 compressed by the pressed drawer 4 can push this drawer 4 and therefore the cam 6 to the neutral position.

The control of the solenoid valve 32 can be ensured by a limit switch contact (not shown) controlling the unlocking at the end of movement, for example of a jack connected to the orifice _D , or on a distributor with hydraulic control controlled by the pressure from the orifice D, by displacement of the slide 33.

The operation of the dispensing device shown in Figure 1 is as follows.

At rest, the control lever 7 is held by the springs 19 in neutral position.

When the lever is tilted in one direction, the corresponding pusher 5 is actuated by the cam 6 including the corresponding calibration spring 16 which pushes the regulation slide 4 downwards.

At the start of the travel of the slide 4, the connection which existed, in neutral position, between the starting orifice D and the exhaust T is removed; as the slide-in stroke of the slide 4 continues, the connection between the pressure inlet groove 8 and the starting orifice D is established by means of the radial channel 17 and the axial channel 14.

Simultaneously, the other pusher 5, diametrically opposite to that which is depressed, is kept in contact against the cam 6 by the effect of the corresponding spring 22. The slide 4 and the plunger 26 progressively rise until the recess g (groove 30) connects the groove 8 with the corresponding chamber 9. The resulting flow of fluid in the chamber 9, through the nozzle 11, creates a pressure drop and an increase in pressure in the chamber 9. This pressure causes the slide 4 and the plunger 26 which will come up abutment against the bottom of the blind bore 27. The corresponding push-button 5 goes up in turn driving the cam 6 and the lever 7.

Hydraulic locking is performed. The user can release the lever 7 without the dispensing function being interrupted.

At the end of the operation, as explained above, the solenoid valve 32 establishes, through its drawer 33, communication between the diametrically opposed chambers 9 and the equalization of the pressures in these chambers 9 cause the lever 7 to be unlocked and returned to position 9 , in particular due to the action of that of the springs 19 which is compressed.

The nozzles 11, which establish a communication with the tank, allow the decompression of the bedrooms 9.

In the event of an emergency stop, and for safety reasons, the user can return to neutral position at any time by acting on lever 7 with reasonable effort.

As can be seen in FIGS. 1 and 4, all the openings for the arrival of pressurized fluid, for return to the reservoir and for departure are advantageously provided on the same face of the distributor 1; according to the representation in FIG. 1, this is the lower face remote from the cam 6.

The layout of the pipes in the body 2 is particularly simple, in particular because of the situation of the starting orifice D in the axial extension of the channel 14.

Generally, the body 2 has a lower part 2b, attached, as visible in FIG. 1. The separation between the part 2b and the body 2 is advantageously carried out at the end surface of the Part 15 of the drawer 4 in the neutral position. Thus, the bore 3 in which the major part of the slide 4 slides, and the bore in which the end portion 15 slides are provided in the same part 2 and their concentricity can be obtained under good conditions, when the making.

FIG. 2 illustrates an alternative embodiment in which the dispensing device is still equipped with regulation drawers. The numerical references used in FIG. 1 are repeated, possibly accompanied by the letter c in FIG. 2, to designate identical elements or playing similar roles. The description of these elements will not be repeated in detail.

The differences in construction between FIG. 2 and FIG. 1 will essentially be noted.

The chambers 9c are provided at the end of the bore 3 in which the drawer 4c slides. The transverse surface b partially limiting the chamber 9c is formed by the frontal annular end surface of drawer 4c. This drawer has an axial channel 14 transforming, in the area facing the chamber 9c, into a cylindrical housing 34 of larger diameter, which opens towards the chamber 9c. A needle 35 is slidably mounted in a sealed manner in this housing 34; this cylindrical needle 35 bears, at one end, against the bottom of the chamber 9c. The two ends of the needle 35 are rounded.

The spring 19 is compressed between the bottom of the chamber 9c and and an annular flange facing outwards from a bush 36 mounted on the end zone of the drawer 4c; the sleeve 36 has an inner rim 37 bearing against the transverse surface b of the drawer 4c.

While in FIG. 1, the departure of the fluid intended for the member of use, for example a jack, was carried out along the axis of the drawer 4, in the embodiment of FIG. 2, this departure takes place at from a radial pipe 38 provided in the coros 2 between the groove 8 and the bearing area of the spring 22. The drawer 4c has, on its periphery, between the radial channels 16 and 17, an annular groove 39 connected to the channel axial 14 and intended to establish communication between the groove 8 for the arrival of pressurized fluid and the outlet pipe 38.

G The recess is formed by a clearance peri- ^p hérique 40 provided at the end of the drawer 4c.

The starting pipe 38 is connected by a bore, not shown, to the underside of the part 2b.

The operation of the dispensing device of FIG. 2 is similar to that of FIG. 1.

When a pusher 5 is pressed, the diametrically opposite pusher follows the cam while rising and driving the corresponding drawer 4c.

When the recess g, formed by the peripheral clearance 40 arrives at the level of the groove 8 for the arrival of pressurized fluid, the chamber 9c receives pressurized fluid, and the pressure drop through the nozzle 11 causes the rise in pressure from this room. The needle 35 then recovers in its housing 34 under the effect of the pressure and abuts against the bottom of this housing. The plunger 4c also rises under the effect of the pressure, and the head 25a abuts against the bottom of the bore 27.

Hydraulic locking is obtained under the same conditions as those mentioned above.

Unlocking can be ensured by placing the chambers 9c in communication under conditions similar to those explained with reference to FIG. 4.

It should be noted that if the springs 22 constitute simple and effective means of returning the pushers 5 to keep them in abutment against the cam 6 when the latter tends to move away from them, one could imagine other types return means, for example a mechanical connection between the cam 6 and the pusher 5.

FIG. 3 shows an alternative embodiment of the dispensing device according to which the drawer 4d is a simple dispensing drawer, the insertion of which is controlled by the direct mechanical thrust of the pusher 5; for this, the head 25d of the plunger linked to the drawer 4d is in abutment against the bottom of the blind bore 27 of the pusher 5. There is, at the end of the drawer 4d, distant from the pusher 5, a chamber 9c such as that shown in Figure 2 and just described. The recess g is always formed by an annular peripheral clearance 40 provided at the end of the drawer 4d, the section of which is full.

This distribution drawer 4d has, in its central zone, a groove with flared walls 41 ensuring the desired communications during the movement of the drawer 4d.

There is, of course, the spring 22 provided between the body 2 and the cup 23 of the pusher 5.

The operation is similar to that described above.

When a pusher 5 is depressed by the cam 6, the diametrically opposite pusher remains in abutment against the cam under the effect of the spring 22, and raises the drawer 4d. For a sufficient stroke of this drawer 4d upwards, the groove 41 comes into communication with the groove 8 for the arrival of pressurized fluid which is thus admitted into the chamber 9c. Hydraulic locking occurs as explained above.

Unlocking can be obtained automatically under the same conditions as those explained with reference to Figures 1 and 4.

Other forms of drawers with differential sections could be envisaged.

It should be noted that the spring 22 ensures permanent contact of the pusher 5 with the cam 6 and helps to avoid impacts between these two parts. The spring 19 maintains the neutral position when the manipulator is unlocked.

Claims (9)

1 - Fluid distributor device, in particular for remote control comprising a body provided with bores with parallel axes in which are mounted sliding drawers associated in pairs, in particular symmetrically with respect to the axis of the body, these drawers being controlled by pushers actuated by an oscillating cam or the like to establish the desired communications between a pressurized fluid inlet, a low pressure fluid reservoir, and a starting orifice towards a user member, each drawer bore having a connected groove on the arrival of pressurized fluid, each drawer being combined with a chamber limited by at least one transverse annular surface of the drawer and connected to the reservoir by a throttle, characterized in that it comprises return means (R) of each pusher (5) capable of maintaining a first pusher in permanent support against the cam (6) when the latter tends to move away from said pusher during of the driving-in movement of a second associated pusher, the drawer (4) corresponding to the first pusher being driven by the latter in its movement, and by the fact that each drawer has, on its periphery, towards its remote end (15) of the pusher, a recess (g) whose arrangement and length are such that before the end of the complete displacement of the drawer (4) during its drive by the first pusher, said recess establishes a connection between the arrival of fluid under pressure (p, ₈ ) and the aforesaid chamber (9), the assembly being such that there is a rise in pressure of the fluid in this chamber (9) which ensures the locking of the drawer (4) and the first pusher ( 5) in the high position and, consequently, the locking of the other pusher and of the corresponding drawer in the low position. 2 - Device according to claim 1caractérisé in that the return means (R) comprise elastic return means, in particular formed by a spring (22) bearing at one end against the body (2), and at the other end against the pusher (5), abutment surfaces (24,25) being provided between the pusher and the drawer to allow the drawer to be driven by the pusher. 3 - Device according to claim 1 or 2, characterized in that the recess (g) provided at the periphery of the drawer (4) is formed by a peripheral clearance forming an annular gorae (30; 40). Device according to any one of the preceding claims, in which the drawer is a regulation drawer, the insertion of which is controlled, from the pusher, by means of a calibration spring so that the pressure of the fluid, at the outlet orifice can be adjusted, characterized in that the starting orifice (D) is provided in the axis of the bore (3) of the regulating slide (4), which has an axial channel ( 14) opening at one end (15) towards said starting orifice (D), the aforesaid chamber (9) being provided in the body (2) of the distributor and being located in the direction of the axis of the bore between the zone (21) of this bore where the axial channel (14) and the groove (8) connected to the pressure inlet (P) open. 5 - Device according to any one of claims 1 to 3 wherein the drawer is a regulation drawer whose penetration is controlled, from the pusher, by means of a calibration spring so that the pressure fluid, at the outlet, can be adjusted, characterized in that the chamber (9c) is provided at the end of the bore (3) in which the drawer (4c) slides, this drawer comprising a axial channel (14) which transforms in the zone facing the chamber (9c) into a cylindrical housing (34) opening towards the chamber and in which a needle (35) is slidably mounted in a sealed manner, this needle (35 ) taking support from one end against the bottom of the chamber (9c), a pipe (38) being provided in the body (2) between a groove (8) connected to the pressure inlet and the bearing area of the calibration spring (22 ) and this pipe (38) serving as the starting pipe. 6 - Device according to any one of claims 1 to 3 in which the drawer is a dispensing drawer characterized in that the chamber (9c) is provided at the end of the drawer (4d) opposite the pusher (5), the insertion of the drawer being controlled by the direct mechanical thrust of the pusher (5), the recess (g) being formed by an annular peripheral clearance (40) ^p revised at the end of the drawer (4d). 7 - Device according to any one of the preceding claims, characterized in that it comprises an automatic locking control comprising a set of connecting pipes between the two chambers (9, 9c) of the drawers diametrically opposite the passage of the fluid in this set of pipes (31) being controlled by a drawer (33) housed in a section of pipe of the set (31). 8 - Device according to claim 7 characterized in that the slide (33) is that of a solenoid valve (32), in particular controlled by a limit switch contact. 9 - Device according to any one of the preceding claims, characterized in that the constriction (e) connecting between each chamber (9c) and the tank is formed by a nozzle (11) mounted in a pipe (12) connecting the chambers with a channeling (10) leading to the reservoir. 10 - Device according to any one of the preceding claims, characterized in that the pressurized fluid inlet, return to the reservoir and outlet orifices are provided on the same face of the distributor, generally the face opposite to that next to the cam (6). 11. Device according to any one of the preceding claims, characterized in that it comprises a spring (19), housed in a space (20) provided towards the end (15) of the drawer (4) facing towards starting orifice (D), to ensure that the drawer is kept in the neutral position when the device is unlocked.

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