US3662782A

US3662782A - Distributing devices for fluid under pressure

Info

Publication number: US3662782A
Authority: US
Inventors: Marcel Rene Schott
Original assignee: SNECMA SAS
Current assignee: Safran Aircraft Engines SAS
Priority date: 1970-02-25
Filing date: 1971-02-16
Publication date: 1972-05-16
Anticipated expiration: 1989-05-16
Also published as: DE2106195A1; FR2080173A5; GB1341290A; DE2106195C2

Abstract

Two distributors for liquid are actuated by two lateral rods which are provided at two end points of a cross bar whose middle point is provided on a central rod. Two threshold mechanical systems are provided at the level of the two hinges on the cross bar on the lateral rods. The device is useful for controlling a double-acting jack and especially in systems for actuating the control surfaces of an aircraft.

Description

[ 51 May 16, 1972 DISTRIBUTING DEVICES FOR FLUID UNDER PRESSURE Inventor: Marcel Rene France Soeiete Nationale DEtude Et De Construction De Moteurs D'Avialion, Paris, France Feb. 16, 1971 Schott, Bois-Colombes,

Assignee:

Filed:

Appl. No.:

Foreign Application Priority Data [5 6] References Cited UNITED STATES PATENTS 3,590,690 7/ l 971 Dalbers ..9 H444 Primary Examiner-Henry T.- Klinksiek Attorney-Larson, Taylor & Hinds [57] ABSTRACT Two distributors for liquid are actuated by two lateral rods which are provided at two end points of a cross bar whose middle point is provided on a central rod. Two threshold Feb. 25, 1970 France ..700681 I mechanical Systems are provided at the level f the two hinges on the cross bar on the lateral rods. The device is useful for US. Cl ..137/596, 91/444 controlling a doub|e acfing jack and especially in Systems f Int. Cl. ....Fl5b 13/04, Fl 6k 11/ 1O actuatingvthe comm] surfaces f i ft Field of Search ..244/78, 85; 91/444, 448;

137/595, 596 9 Claims, 5 Drawing Figures 51] 6' Z Q a Jd 0 s FL\2 J Patented May 16, 1972 3,662,782

3 Sheets-Sheet 1 Patented May 16, 1972 3 Sheets-Sheet 2 Patented May 16, 1972 3,662,782

3 Sheets-Sheet Z DISTRIBUTING DEVICES FOR FLUID UNDER PRESSURE The invention relates to distributing devices for fluid under pressure, especially a liquid.

It has already been proposed to produce distributing devices for fluid under pressure which comprise two distributors actuated respectively by two lateral rods parallel between themselves and pivoted at two extreme points of a cross bar of which the middle point is pivoted on a central rod constituting the control member of the distributing device.

Such distributing devices enable the duplication of circuits of fluid under pressure, hence the reduction of the risks of misfunctioning due to blockage or to jamming occurring between the members in relative movement constituting the two distributors.

It is an object of the invention to improve further distributing devices of the type mentioned above, especially to render their operation automatic, i.e.' that the appearance of blocking or jamming causes a change in the relative position of the members in motion of the two distributors, which change remains without effect on the operation of the distributing device, and the disappearance of the blocking or of the jamming causes the reestablishment of the initial relative position of the members in motion of the two distributors.

The invention applies more particularly to distributing devices intended for aircraft hydraulic control systems, and this by reason of the great reliability that such distributing devices must possess.

Taking this application into account, the invention has also the object of providing a distributing device which is simple, reliable, and robust and which retains a small bulk and compact arrangement, this group of properties being particularly advantageous in the field of equipment incorporated in aircraft.

The distributing device according to the invention is characterized by the fact that the two distributors are mounted in series in the circuit of fluid under pressure, and by the fact that at least one mechanical threshold system cooperates with one at least of the three pivots of the cross bar,

mechanical threshold system being arranged so as, on one hand, to block the pivots as long as the forces 'at the level of these pivots do not exceed a critical value corresponding to the normal frictional forces between the members in relative movement of the two abovesaid distributors, the cross bar then occupying an angular position perpendicular to the two lateral rods, and, on the other hand, to free these pivots when the abovesaid forces exceed the abovesaid critical value, the cross bar being then able to occupy different angular positions with respect to the two lateral rods,

this mechanical threshold system comprising elastic return means restoring the crossbar into its angular position perpendicular to the two lateral rods as soon as the forces concerned have again become less than the critical value which had caused the triggering of the mechanical threshold system,

the members in relative movement of the two distributors occupying similar positions in these two distributors when the cross bar occupies its angular position perpendicular to. the two lateral rods.

In a preferred embodimentof the invention, the crossbar comprises detector means adapted to indicate any separation of the cross bar, from one side or the other, from its :angular position perpendicular to the two lateral rods.

If ablocking or a jamming of the members inrelative movement occurs in one of the two distributors when the said members prevent the passage of fluid, manipulation ofithe central rod will cause pivoting of thecross' bar around its pivoting point on the lateral rod of the blocked or jammed distributors, which will have only the effect of triggering the detector means.

On the other hand, if a blocking or jamming of the members in relative movement in one of the two distributors occurs when the said members permit the passage of fluid, the manipulation of the central rod will cause pivoting of the cross bar around its pivoting point on the lateral rod of the blocked or jammed distributor, whichwill have the effect, on one hand, of displacing the members in relative movement of the distributor operating correctly (i.e. not blocked or jammed) and of bringing the said members into their position for which they prevent the passage of fluid, and, on the other hand, of triggering the detector means.

From the safety point of view, the main criterion in the field of aeronautics, any manipulation of an important element of the aircraft (control surfaces, tail plane, etc.) is impossible if one of the two distributors is blocked or jammed, this impossibility and this malfunctioning being immediately indicated by the detector means, and this manoeuvre can be immediately stopped if one of the two distributors is blocked or jammed, this stoppage and this malfunctioning being immediately indicated by the detectormeans.

Other features of the invention, which are preferably used at the same time, will be described below.

The invention will, in any case, be well understood with the aid of the supplementary description which follows as well of the accompanying drawings, which supplement and drawings relate to preferred embodiments of the invention and are not, of course, to be regarded as in any way limiting.

In the drawings:

FIG. 1 is a diagrammatic view showing one embodiment of a distributing device constructed according to the invention and applied to the control of a double acting hydraulic jack;

FIGS. 2, 3 and 4 are sections showing various operating conditions of another embodiment of a distributing device constructed according to the invention;

and lastly,

FIG. 5 is a diagram of a hydraulic control circuit of the tail plane of ,an aircraft, which circuit is equipped with two distributing devices according to that shown in FIGS. 2, 3 and 4.

As shown in FIGS. 1 to 4, the distributing device according to the invention comprises two distributors 1 and 2, preferably and as will be assumed below, identical, these two distributors l and 2 being mounted in series in a high pressure hydraulic circuit 3.

Two lateral rods 4 and 5, parallel between themselves, are provided to actuate respectively these two distributors l and 2 which can be, as has been illustrated, slide valve distributors (in which case the lateral rods are rigidly fixed directly to the slide valve) or rotary valve face distributors (in which case the lateral rods are connected to the faces by a kinematic rack and pinion linkage).

These two lateral rods 4 and 5 are pivoted at the two extreme points of a cross bar 6 of which the middle point is pivoted on a central rod 7 constituting the control member of a distributing device.

At least one threshold mechanical system cooperates with at least one of the three pivots of the cross bar 6 so as,

on one hand, to block the pivots aslong as the forces at the level of these pivots do not exceeda critical value corresponding to the normal frictional forces between the slide valves and the cylinders of the two distributors 1 and 2, the the cross bar 6.then occupying an angular position perpendicular to the two lateral .rods 4 and 5,

and on the other hand, to free these pivots when the abovesaidforces exceed the abovesaid critical value, the cross bar 6 then being able to occupy different angular positions with respect to the two lateral rods4 and 5 (FIGS. 3 and 4).

As regards the one or more mechanical threshold systems, a single mechanical threshold system can be provided at the :level of the pivot of the cross bar 6 on the central rod 7, or two mechanical threshold systems, 8 and 9, .respectively at the level of the .two pivots-of the cross bar 6 on the lateral rods 4 and 5, the latter solution being that adopted for the two embodiments of the invention (illustrated respectively in FIGS. 1 and 2 to 4).

In any case, the one or more mechanical threshold systems comprise elastic return means '10 (FIGS. 2 to-4) restoring the cross bar 6 into its angular position perpendicular to the two lateral rods 4 and 5 as soon as the forces at the level of the corresponding pivots have become less than the critical value which cause the triggering of the one or more mechanical threshold systems.

The slide valves of the two distributors l and 2 occupy similar positions in these two distributors when the cross bar 6 occupies its angular position perpendicular to the two lateral rods 4 and 5 (FIGS. 1 and 2).

Preferably, the cross bar 6 comprises detector means 11 adapted to indicate any departure of the cross bar 6, to one side or the other, from its angular position perpendicular to the two lateral rods 4 and 5.

As regards the two mechanical threshold systems 8, 9 and when the central rod 7 is parallel to the two lateral rods 4 and 5, it is advantageous to constitute them each by an elastic linkage interposed, in the neighborhood of the pivot concerned of the cross bar 6 on the lateral rod 4 or 5, between the cross bar 6 and a rigid arm 12 firmly fixed to the central rod 7 and extending on both sides of the said central rod 7 parallel to the cross bar 6 (FIGS. 2 to 4).

As for the detector means 1 1, they can be constituted by an assembly of electrical contacts arranged at the level of the pivot of the cross bar 6 on the central rod 7 (FIGS. 2 to 4).

A distributing device according to the invention lends itself well to use in a hydraulic servo-control circuit.

As shown in FIG. 1, the receiving control member is a double-acting hydraulic jack whose piston 21 is fixed and the body 22 connected to the element to be moved. The distributing device according to the invention is arranged to occupy three positions, namely, a neutral position for which it prevents the passage of liquid, and two active positions for which it permits the passage of liquid towards one or other of two working chambers of the double-acting jack 20. This distributing device is rigidly fixed to the body 22 of the jack 20 and the central rod 7 is pivoted on a control lever 23 of which one of the ends is pivoted on the body 22 of the jack 20, the operator acting on this lever 23 to trigger the operation of the jack 20, this control lever 23 constituting the servo-return loop and the mixer on which the operator acts.

To simplify the diagram which is the subject of FIG. 1, there has been shown only the supply circuit of the jack 20, without showing its reservoir connection circuit.

In FIGS. 2 to 4, there is shown a distributing device according to the invention intended to supply a hydraulic motor 30 with two directions of rotation. This distributing device is arranged to occupy three positions, namely, a neutral position for which it prevents the passage of liquid, and two active positions for which it permits the passage of liquid towards one or other of two connections to the hydraulic motor 30. The inlet for the high pressure liquid in the .distributing device is denoted by the reference 31, whilst the two outlets of high pressure liquid towards the hydraulic motor 30 are denoted by the

references

32 and 33. In the direction or rotation of the hydraulic motor 30, the outlet 32 or the outlet 33 is placed in communication with the reservoir through a system of internal passages arranged in the distributing device proper which has two outlets towards the reservoir, 34 and 35, adapted each to the two distributors l and 2 and connected in parallel on the reservoir circuit 36.

In FIG. 2, the distributing device is shown in its neutral position. If the central rod 7 is moved upwardly, the hydraulic motor 30 is supplied through the outlet 32, the outlet 33 being linked to the reservoir, while if the central rod 7 is moved downwardly the hydraulic motor 30 is supplied through the outlet 33, the outlet 32 being connected to the reservoir.

In FIGS. 3 and 4, the distributing device is shown in a position corresponding to one of the slide valves blocked or jammed in an active position (slide valve of the distributor l in FIG. 3 and slide valve of the distributor 2 in FIG. 4) and the other slide valve brought into its neutral position (slide valve of the distributor 2 in FIG. 3 and slide valve of the distributor l in FIG. 4).

In FIG. 5, which shows a hydraulic servo control circuit for the operation of the tail plane of a large capacity aircraft equipped with two different hydraulic generators A and B, the

same reference numerals denote the same members as in the preceding Figures but supplemented with an index a or b according as they occur on the hydraulic generator A or B.

In this hydraulic circuit are incorporated two distributing devices according to the invention intended to supply, one, the hydraulic motor 30a, the other, the hydraulic motor 30b.

The motors 30a and 30b drive respectively two of the three elements of an epicyclic gear train 40, of which the third element drives, through a gear train 41, a worm gear 42 in mesh with a nut 43 mechanically linked to the tail plane (not shown). Each of the shafts of the motors 30a and 30b comprises a blocking device 44a, 44b actuated by a hydraulic jack 45a, 45b.

The two servo-loops are constituted by a gear train 46a, 46b driving one of the three elements of an

epicyclic gear train

47a, 47b of which the second element acts on the central rod 7a, 7b of the distributing device concerned and of which the third element is connected to the manual controls of the pilot 48a, 48b, which manual controls are connected by a mechanical link 49.

By means of this hydraulic circuit, it is observed that,

if one of the slide valves of the distributing device of one of the hydraulic generators is blocked or jammed in its neutral position, the operation is effected automatically on the other hydraulic generator, and an alarm warns the pilot,

if one of the slide valves of one or other of the two distributing devices is blocked or jammed in an active position, the operation is rapidly stopped and an alarm warns the pilot.

It will be observed therefore that the distributing device according to the invention has characteristics of simplicity, of reliability, of robustness, which are very advantageous for aeronautic applications.

Moreover, it preserves a small bulk and a compact arrangement.

As is self-evident and as emerges already from the preceding description, the invention is in no way limited to those of its methods of application, nor to those of its methods of production of its various parts, which have been more especially indicated; it encompasses, on the contrary, all variations.

I claim:

1. Distributing device for fluid under pressure, comprising two distributors (which can be identical) actuated respectively by two lateral rods parallel between themselves and pivoted at two end points of a cross bar of which the middle point is pivoted on a central rod constituting the control member of the distributing device, wherein said two distributors are mounted in series in the circuit of pressurized fluid, and wherein at least one threshold mechanical system cooperates with one at least of the three pivots of the cross bar,

said threshold mechanical system being arranged so as to block said pivots as long as the forces at the level of said pivots do not exceed a critical value corresponding to the normal frictional forces between the members in relative movement of the two abovesaid distributors, the cross bar occupying then an angular position perpendicular to the two lateral rods, and to free said pivots when the abovesaid forces exceed the abovesaid critical value, the cross bar being then able to occupy different angular positions with respect to the two lateral rods,

said threshold mechanical system comprising elastic return means restoring the cross bar into its angular position perpendicular to the two lateral rods and as soon as the forces concerned have become less than the critical value which caused tripping of the threshold mechanical system,

the members of the two distributors in relative movement occupying similar positions in said two distributors when the cross bar occupies its angular position perpendicular to the two lateral rods.

2. Distributing device according to claim 1, wherein the cross bar comprises detector means adapted to indicate any departure of the cross bar on one side or the other from its angular position perpendicular to the two lateral rods.

3. Distributing device according to claim 1, comprising a single threshold mechanical system at the level of the pivot of the cross bar on the central rod.

4. Distributing device according to claim 1, comprising two threshold mechanical systems, respectively at the level of the two pivots of the cross bar on the lateral rods.

5. Distributing device according to claim 4, wherein the central rod is parallel to the two lateral rods, and the two threshold mechanical systems are constituted each by an elastic linkage interposed in the vicinity of the pivot concerned of the cross bar on the lateral rod, between the cross bar and a rigid arm firmly fixed to the central rod and extending on both sides of said central rod parallel to the cross bar.

6. Distributing device according to claim 2, wherein the detector means are constituted by an assembly of electrical contacts arranged at the level of the pivot of the cross bar on the central rod.

7. Distributing device according to claim 1, wherein the central rod is connected to a servo-controlled restoring mechanical linkage.

8. Distributing device according to claim 4, wherein the detector means are constituted by an assembly of electrical contacts arranged at the level of the pivot of the cross bar on the central rod.

9. Hydraulic circuit with two different hydraulic generators, comprising two distributing devices according to claim 1, disposed respectively in the two hydraulic generators and arranged so that, it a blockage or jamming occurs in one of the two distributing devices when this distributing device prevents the passage of liquid, manipulation of the central rod of said distributing device causes automatic control of the other distributing device while indicating if necessary the blocking or jamming of one of the two distributing devices.

Claims

1. Distributing device for fluid under pressure, comprising two distributors (which can be identical) actuated respectively by two lateral rods parallel between themselves and pivoted at two end points of a cross bar of which the middle point is pivoted on a centraL rod constituting the control member of the distributing device, wherein said two distributors are mounted in series in the circuit of pressurized fluid, and wherein at least one threshold mechanical system cooperates with one at least of the three pivots of the cross bar, said threshold mechanical system being arranged so as to block said pivots as long as the forces at the level of said pivots do not exceed a critical value corresponding to the normal frictional forces between the members in relative movement of the two abovesaid distributors, the cross bar occupying then an angular position perpendicular to the two lateral rods, and to free said pivots when the abovesaid forces exceed the abovesaid critical value, the cross bar being then able to occupy different angular positions with respect to the two lateral rods, said threshold mechanical system comprising elastic return means restoring the cross bar into its angular position perpendicular to the two lateral rods and as soon as the forces concerned have become less than the critical value which caused tripping of the threshold mechanical system, the members of the two distributors in relative movement occupying similar positions in said two distributors when the cross bar occupies its angular position perpendicular to the two lateral rods.

9. Hydraulic circuit with two different hydraulic generators, comprising two distributing devices according to claim 1, disposed respectively in the two hydraulic generators and arranged so that, if a blockage or jamming occurs in one of the two distributing devices when this distributing device prevents the passage of liquid, manipulation of the central rod of said distributing device causes automatic control of the other distributing device while indicating if necessary the blocking or jamming of one of the two distributing devices.