US3225663A

US3225663A - Hydraulic control systems including double action receiver apparatus

Info

Publication number: US3225663A
Application number: US357666A
Authority: US
Inventors: Pelisson Claude Georges Julien
Original assignee: Hispano Suiza SA
Current assignee: Safran Transmission Systems SAS; Societe dExplotation des Materiels Hispano Suiza
Priority date: 1963-04-09
Filing date: 1964-04-06
Publication date: 1965-12-28
Anticipated expiration: 1982-12-28
Also published as: FR1361466A

Description

D 8, 1965 c. G. D. J. PELISSON 3,225,663

HYDRAULIC CONTROL SYSTEMS INCLUDING DOUBLE ACTION RECEIVER APPARATUS Filed April 6, 1964 4 Sheets-Sheet 1 D 8, 1965 c G. D. J. PELISSON 3,225,563

HYDRAULIC CUNTROL SYSTEMS INCLUDING DOUBLE ACTION RECEIVER APPARATUS Filed April 6, 1964 4 Sheets-Sheet 2' ATTORNEY Dec. 28, 1965 c. e. D. J. [PELISSON 3,225,663

HYDRAULIC CONTROL SYSTEMS INCLUDING DOUBLE ACTION RECEIVER APPARATUS Filed April 6, 1964 4 Sheets-Sheet 3 m T m V W ATTORNEY De 8, 1965 c. G. D. .1. PELISSON 3,225,663

HYDRAULIC CONTROL SYSTEMS INCLUDING DOUBLE ACTION RECEIVER APPARATUS 4 Sheets-Sheet 4 Filed April 6, 1964 //\/VENTOR ATTORNEY United States Patent f 3,225,663 HYDRAULIC CONTROL SYSTEMS INCLUDING DOUBLE ACTION RECEIVER APPARATUS Claude Georges Daniel Julien Pelisson, Sartrouville, France, assignor to Societe dExploitation des Materiels Hispano-Suiza, Seine, France, a society of France Filed Apr. 6, 1964, Ser. No. 357,666 Claims priority, application France, Apr. 9, 1963, 930,942, Patent 1,361,466 3 Claims. (Cl. 91305) The present invention relates to hydraulic control systerns for double acting receiver apparatus, that is to say receiver apparatus the movable elements of which have a reciprocating movement between two end positions determined by abutments, the displacements of said movable elements being produced hydraulically in both directions. The invention is more especially concerned with systems of this kind for simultaneously actuating several receiver apparatus mounted in parallel.

The chief object of the present invention is to provide a system of this kind which is better adapted to meet the requirements of practice.

Such systems include at least one double acting receiver apparatus operated by means of a reversing distributing valve adapted, according to the position it occupies, to send the power liquid into one or the other of the two chambers of said receiver apparatus, the chamber that is not fed with liquid being connected with an outflow conduit, said reversing distributing valve being hydraulically operated by two detector devices connected respectively with the working chambers of the double acting receiver apparatus and being responsive, against the action of a return spring, to the increase of pressure produced in the corresponding working chamber of said receiver when the liquid fed to said last mentioned chamber has brought the movable element of the receiver apparatus into one of its abutment end positions, this increase of pressure causing the reversing distributing valve to switch from one position to the other. The invention consists in providing each of said detector apparatus with a supplementary working chamber where the pressure is in opposition with that in the main working chamber of said detector and cooperates with said return spring, the supplementary working chamber of each of said detector devices being connected with the conduit for leading power liquid to the main chamber of the other detector apparatus, whereas the supplementary chamber of said other detector apparatus is connected with the conduit controlling the main chamber of the first mentioned detector apparatus, Whereby the operation of the system is independent of possible variations of the discharge pressure.

A preferred embodiment of the present invention will be hereinafter described with reference to the appended drawings, given merely by Way of example, and in which:

FIG. 1 diagrammatically shows a hydraulic control system according to the present invention;

FIGS. 2, 3 and 4 show the same system for diflerent relative positions of its elements corresponding to four successive steps of its operation.

In the following description, it will be supposed that the system serves to actuate, alternately in one direction and in the opposed one, the movable elements of double acting receiver apparatus. In the embodiment illustrated by the drawings the receiver apparatus are hydraulic jacks 1. Said jacks 1 are mounted in parallel between two feed conduits L and L Each of said jacks comprises two working chambers C and C communicating respectively with conduits L and L respectively, said chambers being separated from each other by a piston 2. Piston 2 forms, together with a rod 3 rigid therewith, the movable element of the jack.

3,225,653 Patented Dec. 28, 1965 Use is made of a hydraulic circuit 4 to which liquid under pressure is supplied from a pump 5, for-instance of the adjustable flow rate type.

Upstream of conduits L and L I provide a reversing distributing valve 6 which, according to the position occupied by its slide valve 6a, acts as follows:

Either it feeds liquid to the working chambers C of jacks 1 through conduit L and places the working chambers C of said jacks in communication, through conduit L with an outflow conduit 7 through which the liquid is returned to a tank, not shown, this operation corresponding to the positions shown by FIGS. 1 and 2;

Or it feeds liquid under pressure to working chambers C through conduit L and places working chambers C into communication with outflow conduit 7 through conduit L (case of FIGS. 3 and 4).

The reversing distributing valve is hydraulically controlled by two detector devices D and D respectively in communication with working chambers C and C through conduits 8 comunicating with the portions of conduits L and L upstream of jacks 1. Said detector devices D and D are operative by the pressure rises produced in working chambers C and C when the pistons 2 of jacks 1 have reached the ends of their strokes. Reversing distributing valve 6 is arranged in such manner that the action of said pressure rises in the main chamber 8a or 8b, of the detector device D or D respectively, that is concerned causes slide valve 6a to shift from the end position it occupied precedingly into its other end position.

With such an arrangement, when the pistons 2 of jacks I reach the ends of their strokes, they automatically produce, due to the pressure rises occurring in working chambers C or C the reversing of distributing valve 6 and therefore place said working chambers in communication with outflow conduit 7 whereas the other chambers (C or C are fed with liquid under pressure which will then produce displacement in the opposed direction of said pistons. At the end of this displacement there will be produced a new pressure rise in the active working chambers, producing a further reversing of valve 6 and so on.

It is pointed out that the rise of pressure that causes the reversing of movement, which rise of pressure is communicated along the whole of the conduit L or L that is concerned, can take place only if all of the jacks 1 have reached the ends of their strokes. Thus the last jack 2 to come to the end of its stroke will start the reversing of the movements of all the jacks.

In other words, I obtain, with a system of this type, complete strokes of all the receiver apparatus arranged in parallel. This would not be the case if the reversing of the distributing valve was produced mechanically for instance by the end of the stroke of any of the jacks of the system. In this case the fastest jack would be the only one to have a complete stroke, all the other jacks having their movements reversed before having reached the ends of their strokes.

In the embodiment illustrated by the drawings, each of the detector devices consists of a hydraulic valve capable, under the action of a rise of the pressure existing in the corresponding working chamber C or C of actuating a pilot valve device 9 including a slide valve 9a, said pilot valve controlling the reversing distributing valve 6. Preferably, the hydraulic control of pilot valve 9 and that of distributing valve 6 are performed by means of the liquid delivered by pump 5 in the hydraulic circuit 4 of the system.

For this purpose, said hydraulic circuit 4 feeds liquid:

(a) On the one hand to the distributing chamber 6b of reversing distributing valve 6, which chamber, according to the position of slide valve 6a, may be placed in communication with either of the conduits L and L through which hydraulic jacks 1 are operated;

(b) On the other hand to the chamber 917 of pilot valve 9, which chamber, according to the position of slide valve 9a, may be placed in communication either with one or with the other of two

variable volume chambers

10a and 10b provided at the respective ends of reversing valve device 6, said chambers corresponding to movements of slide valve 6a in one direction and the other, respectively.

Hydraulic circuit 4 further acts, through a branch conduit 40, on the chambers 11 of detector devices D and D Said chambers 11 may be brought into communication, through conduits 4b, respectively, with two

variable volume chambers

12a and 12b provided at the ends of pilot valve device 9 and intended to control the displacements of the slide valve 9 of said device respectively in one direction and in the opposed one.

It suflices, in order to obtain the desired operation under normal condition, to subject the slide valve 11a or 11b of detector device D or D to the action of a spring 13 adapted to permit, under the effect of the pressure rise created at the end of the strokes of pistons 2 in the corresponding conduit 8 and in the chamber 8a communicating therewith, the shifting of said slide valve from its neutral position (shown for detector device D in FIG. 2) to its active position (shown for detector device D in the same figure).

Of course, the

respective valves

8, 9, D and D must be provided with the discharge conduits necessary to their operation, the provision of such discharge conduits being conventional in the art so that it is unnecessary to describe the discharge conduits illustrated by the drawings and through which the above mentioned valves are connected with the general outflow conduit 7.

In FIG. 1 the respective elements of the system are in positions for which the working chamber C of jack 1 is fed with liquid from circuit 4, the piston 2 of said jack 1 being shown in an intermediate position as it moves toward the left. Working chamber C is thus connected, through L with the general outflow conduit 7. Furthermore, as no pressure rise has still occurred, both of the detector valves D and D are in position of rest.

FIG. 2 shows the elements of the system at the time where, piston 2 having reached the end of its leftward stroke, there is produced in working chamber C a pressure rise which causes the slide valve of detector device D to move into its active position against the resilient action of the corresponding spring 13. In said FIG. 2 it is supposed that pilot valve 9 and reversing valve 6 have not yet reacted to the coming of the slide valve of detector device D into active position.

FIG. 3 shows this effect, that is to say the shifting of slide valve 9a into the other end position thereof and the consequent shifting of the slide valve 6a of distributing valve 6 resulting therefrom. Finally FIG. 4 shows the consequence of the reversing movement of distributing valve 6, that is to say the movement toward the right of the piston 2 of jack 1. This piston is shown, in FIG. 4 in an intermediate position, that is to say in a position where there is not yet a pressure rise in chamber C and where both of the detector valves D and D are conseqently in position of rest.

It will be understood that an increase of the outlet pressure with respect to its normal value causes an increase of the pressure existing in one of the working chambers C or C (according to the direction of displacement of piston 2), this increase being due to the fact that the work required from piston 2 has become greater (in view of the fact of the increase of the value of the outlet pressure).

Increase of the pressure existing in C or C being transmitted through conduits 8 to corresponding detector device D or D may therefore tend to move said detector device from its neutral position to bring it into its active position.

Since the force of spring 13 is adjusted to correspond to the normal value of the outlet pressure, an increase of this pressure may therefore cause a premature reversal of the displacement of piston 2.

In order to avoid this drawback and according to the present invention, each of the detector valves D and D comprises a supplementary chamber or compartment 14 in opposition with the main chamber or compartment 8a, 8b of said detector device. The supplementary chamber 14 of detector device D is connected through a conduit 14a with the feed conduit L communicating with the main chamber of detector device D whereas the supplementary chamber 14 of detector device D is connected through a conduit 14b with the conduit L controlling the main chamber of detector device D It should be pointed out that, although said chambers 14 are of larger cross section than the cylindrical casings detector devices D and D the active cross section of each of the slide valves 11a and 11b subjected to the action of the liquid under pressure in said chambers is equal to that of the slide valve subjected to the pressure of the liquid in each of the chambers 8a and 8!) respectively.

The operation of such a system is uninfluenced by possible variations of the pressure existing in the main outflow conduit 7.

In a general manner, while I have in the above description disclosed what I deem to be a practical and efficient embodiment of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the appended claims.

What I claim is:

1. A system for controlling the reciprocating displacements of a piston in a cylinder divided by said piston into two working chambers which system comprises, in combination, a high pressure liquid inflow conduit, an outflow conduit, a reversing distributing valve mechanism including a casing having two different portions thereof in communication with said inflow and outflow conduits respectively and a valve member movable in said casing, two connecting conduits extending between two different portions of said casing and said working chambers, respectively, said valve member being switchable in said casing from one to the other of two positions, in one of which it places in communication one of said connecting conduits with said inflow conduit and the other of said connecting conduits with said outflow conduit, and in the other of which it reverses said communications, two detector devices each comprising a casing, a slide valve in said last mentioned casing adapted to divide it into several compartments two of which, a first one and a second one, are of variable volume, spring means between each of said detector device casings and the corresponding slide valve for resiliently opposing increase of the volume of said first compartment, conduit means for connecting said first chambers with said connecting conduits respectively, means operatively connected with said detector devices, with said high pressure inlet conduit and with said reversing distributing valve mechanism for switching said reversing distributing valve mechanism from one of said positions to the other in response to a rise of pressure in one of said connecting conduits, and conduit means for connecting the second compartment of each one of said detector devices with the connecting conduit corresponding to the other of said detector devices.

2. A system which comprises, in combination, a plurality of cylinders, a plurality of pistons fitting slidably in said cylinders respectively and dividing each of said cylinders into two working chambers, a first one and a second one, a high pressure liquid inflow conduit, an outflow conduit, a reversing distributing valve mechanism including a casing having two different portions thereof in communication with said inflow and outflow conduits respectively and a valve member movable in said casing, two connecting conduits extending from two different portions of said casing, respectively, said cylinders being inserted in parallel between said two connecting conduits, all the first chambers of said cylinders being in communication with one of said two connecting conduits and all the second chambers of said cylinders being in communication with the other of said two connecting conduits, respectively, said valve member being switchable in said casing from one to the other of two positions, in one of which it places in communication one of said connecting conduits with said inflow conduit and the other of said connecting conduits with said outflow conduit, and in the other of which it reverses said communications, two detector devices each comprising a casing, a slide valve in said last mentioned casing adapted to divide it into several compartments two of which, a first one and a second one, are of variable volume, spring means between each of said detector device casings and the corresponding slide valve for resiliently opposing increase of the volume of said first compartment, conduit means for connecting said first compartments with said connecting conduits respectively, means operatively connected with said detector devices, with said high pressure inlet conduit and with said reversing distributing valve mechanism for switching said reversing distributing valve mechanism from one of said positions to the other in response to a rise of pressure in one of said connecting conduits, and conduit means for connecting the second compartment of each one of said detector devices with the connecting conduit corresponding to the other of said detector devices.

3. A system according to claim 1 wherein the casing of each of said detector devices is a cylinder, the slide valve in said cylinder being of the same cross section in the portions thereof that limit said first compartment and said second compartment.

References Cited by the Examiner UNITED STATES PATENTS 1,952,690 3/1934 Strom 91308 2,698,517 6/1955 Witt 91--308 2,944,530 7/ 1960 Severinsen 91-305 FRED E. ENGELTHALER, Primary Examiner.

SAMUEL LEVINE, Examiner.