Device for shutting a jettisoning circuit of an aircraft

A device for shutting an aircraft jettisoning circuit includes a coupling endpiece. The endpiece carries a sealing gasket and means suitable for modifying a dimension of the gasket.

FIELD OF THE INVENTION

The invention relates to devices for shutting aircraft jettisoning circuits.

BACKGROUND OF THE INVENTION

Certain airplanes are provided with a system that serves, when circumstances make this necessary, to dump quickly the fuel contained in the tanks. Such a system is referred to as a jettisoning system. The terms “fuel dumping” and “fuel jettisoning” are in widespread use.

In order to ensure that the jettisoning circuit is operating properly, it is necessary to subject it to leak testing. Testing then consists in putting both the circuit and the tank under pressure by means of an air-helium mixture, e.g. at a nominal pressure of 350 hectopascals (hPa).

It is therefore desirable to have a device that enables the jettisoning circuit to be shut by being fitted to the outlet from the circuit, that enables the pressure that exists inside the circuit to be viewed, and that also enables the circuit to be vented after leak testing has been terminated.

Such a device should be capable of being used on airplane assembly lines and also in workshops that handle airplanes having tanks and fuel circuits that have already received kerosene. That is why such tooling needs to comply with regulatory requirements, in particular with standards relating to non-electric tooling suitable for use in an explosive zone. Thus, the device must make it possible to shut the jettisoning circuit while ensuring that it is properly sealed so as to avoid any risk of fuel being accidentally discharged.

In addition, the device must not damage the metal portions of the airplane. In this respect, a problem that arises when making such a device stems from the outlet configuration of the jettisoning circuit on certain airplanes. This outlet forms a sleeve having an outlet in which it is necessary to insert the device in order to establish sealing between the inside of the sleeve and the device. Nevertheless, the sleeve presents fastening rivets that project into the inside of the sleeve so as to define a passage of a size that is smaller than the size of the zone located beyond the rivets and with which the device is to establish sealing. It is therefore necessary to have a device that can go past the rivets without damaging them, and then establish satisfactory sealing in the following zone.

OBJECT AND SUMMARY OF THE INVENTION

An object of the invention is to provide a jettisoning circuit test device that makes it possible to establish sealing in such an outlet configuration of the circuit.

To this end, the invention provides an aircraft jettisoning circuit shutter device, the device comprising a coupling endpiece, the endpiece carrying a sealing gasket and means for modifying a dimension of the gasket.

Thus, the endpiece may be given, at will, a retraced configuration or an extended configuration in which the dimension of the gasket is greater than in the retracted configuration. It is thus possible to pass the endpiece, while it is in the retracted configuration, through the narrow outlet zone of the circuit, and then to give it an expanded configuration so as to establish sealing with the outlet of the circuit beyond said zone.

Advantageously, the modification means are suitable for modifying a dimension of a segment of the gasket, such as an edge, without modifying a dimension of some other segment of the gasket, such as an edge.

This simplifies making the device insofar as it is generally easier to deform a single segment of the gasket than it is to deform the entire gasket. Furthermore, this arrangement makes it possible to flatten the gasket over only a segment of its length, so that it is not flattened over its entire length as a general rule. In particular, in the shutting position, the gasket generally presents an outside diameter that is not constant along the length of the gasket and it presents a shape that is not cylindrical. Consequently, the device is easier to fit into ducts of diameters that are very different from one another. Furthermore, this adaptability makes it possible to begin by giving the endpiece a total diameter that is much less than that of the duct in which it is to penetrate, in particular so as to avoid damaging certain zones of the duct, e.g. rivets or other elements projecting into the duct in a radial direction.

Preferably, the modification means occupy a main duct of the gasket.

Thus, these means are particularly compact and do not significantly increase the dimensions of the device.

Advantageously, the modification means are mounted to move relative to the gasket.

Advantageously, the modification means present a face forming a ramp for the gasket.

Thus, the diameter of the gasket is modified by sliding over the ramp-forming face.

Preferably, the face presents a curved profile with a center of curvature situated outside the gasket.

Thus, the greater the increase in the diameter of the gasket, the faster it deforms.

Preferably, the modification means are adjustable.

Advantageously, the device includes a member, such as a capstan, for controlling the modification means.

Preferably, the device is suitable for putting the duct and the endpiece into gas-flow communication through the gasket.

The device includes in particular a flexible pneumatic hose and a rotary coupling, the hose and the coupling being suitable for establishing said communication.

Advantageously, the device has a cylinder and means independent of the endpiece for fastening the cylinder to the circuit.

Thus, the function of fastening the shutter device to the jettisoning circuit is not performed, at least for the most part, by the endpiece, but rather by the fastener means. It is thus possible to dedicate the endpiece to the function of providing sealing.

The invention also provides a method of shutting an aircraft jettisoning circuit by means of a device that comprises a coupling endpiece carrying a sealing gasket and means for modifying a dimension of the gasket.

MORE DETAILED DESCRIPTION

There can be seen in particular inFIG. 6, tooling2comprising a pneumatic line4and a shutter device6of the invention.

The pneumatic line4comprises the following elements connected in series one after another and in gas-flow communication with one another: a flexible pneumatic hose8; a metal valve10; a T-coupling12; and finally a rotary coupling14. On its third branch, the T-coupling carries a pressure gauge16provided with a protective collar18. The shutter device6is fastened to the free end of the rotary coupling.

There follows a description of the shutter device given in particular with reference toFIG. 7. The device comprises a cylinder20of generally cylindrical shape about an axis22. At its proximal axial end, it includes a yoke24of annular shape, extending generally in a plane perpendicular to the axis22. The yoke carries two arms26located in geometrically opposite positions on either side of the axis22, these arms being shown in respective top and bottom portions of the figures. Each of the arms26is hinged to the yoke24about a pin28of axis perpendicular to the axis22and not intersecting it. The arms26may thus have a closed configuration in which they are close to the cylinder20and extend parallel to the axis22, as shown inFIGS. 1,3,6, and7, and an open configuration in which they are inclined relative to the axis22and spaced apart from the cylinder20, as shown inFIG. 4. Guides or spacers30, there being two of them in this example, are interposed in the radial direction between the cylinder20and the arms26. The two guides30are identical to each other and they follow one another along the axis22.

The device6includes a rod32of axis22connected via its proximal axial end to the rotary coupling14. This rod is mounted to be movable in rotation relative to the cylinder20about the axis22. It is prevented from moving in translation relative to the cylinder20. At its distal axial end, the rod32presents a threaded male portion having a stopper or actuator34fastened thereon by means of a threaded female portion. In the present example, the main portion of the rod is formed by a part36and the thread of the rod is carried by an end part38fitted to the main portion36, being rigidly fastened thereto.

The stopper34presents circular symmetry about the axis22. It comprises a base40that presents the threaded female portion for connection with the rod. It includes an actuator portion or cam42that presents in particular an outside face44of diameter that increases going from its proximal end towards its distal end. This face presents a profile that is convex in a plane that is radial relative to the axis22, this profile having a center of curvature that extends outside the actuator portion42. In other words, the face44extends between the center of curvature and the axis22. The face44thus has the shape of a trumpet bell.

In the present example, the actuator portion42is fastened to the base40by means of screws, there being three screws in this example, that extend parallel to the axis22and that are regularly distributed about said axis. The orifices associated with the screws pass right through the base40. The stopper includes a protective collar45for protecting the free end of the actuator portion, and likewise screwed thereto in analogous manner.

The cylinder20includes a sealing gasket31of circular symmetry about the axis22, in the form of a cylinder with a hollow center. The gasket31is rigidly fastened via its proximal axial end to the distal end of the cylinder20, while its distal axial end is left free. By way of example, the gasket31is made of ethylene propylene diene monomer (EPDM) having a hardness of 70 on the Shore scale. The actuator portion42of the stopper occupies the central space in the gasket31.

The device includes adjustable control means for moving the actuator portion42relative to the gasket. In the present example, these means comprise a capstan47having two radial arms48carrying respective ball-shaped handles50. The capstan is rigidly fastened to the proximal axial end of the rod32. Means are provided for preventing the stopper34from turning relative to the cylinder, which means comprise, for example, a key46fastened rigidly to the cylinder and extending in a direction that is radial relative to the axis22, being movable in a groove47of the stopper, extending parallel to the axis22. Because of the helical connection between the rod32and the stopper34, turning the capstan about the axis22relative to the cylinder causes the stopper to slide along the axis22relative to the gasket31.

The gasket31bears via its inside face against the outside face44of the stopper.

When the stopper occupies its farthest-forward position relative to the cylinder, i.e. its position farthest to the right inFIG. 7, only the free end portion of the gasket31bears against the face44on the proximal zone thereof, which zone is cylindrical or practically cylindrical in shape. The gasket31is thus in a retracted configuration close to its original cylindrical shape. The outside diameter d of the distal edge of the gasket is small, as shown inFIGS. 1,3, and4.

In contrast, when the stopper34occupies its position closest to the cylinder, i.e. farthest to the left inFIG. 7, the major fraction of the gasket bears against the face44. More precisely, in the present example, the distal end zone of the gasket31presents an outside diameter d that is greater than in the retracted configuration, as shown inFIGS. 6 and 7. Furthermore, since only the distal portion of the gasket31is deformed, the diameter d is greater than the outside diameter of the proximal end zone of the gasket since it bears against the distal end zone of the face44.

The rod32presents a distal cavity62in communication with an open cavity64of the stopper. The rod also presents a proximal cavity66in communication with the rotary coupling14. The two cavities62and66of the rod are in mutual communication via radial orifices and via the center of the cylinder.

The gasket31and the stopper34form a coupling endpiece43.

FIG. 5shows an outlet duct from a jettisoning circuit of an aircraft such as an airplane. Such an outlet duct is situated close to the trailing edge of a wing, for example. As shown here, the duct presents from left to right: an outlet zone50, a fastening zone52, and a bearing zone54, which zones follow one another in this order. The fastening zone includes rivets that extend inside the duct, projecting from its inside face. In this zone, there must therefore be no contact between the endpiece43and the duct48. Specifically, the zones50and54are cylindrical in shape, while the zone52has a flared shape. The inside diameter of the zone54is less than that of the zone50.

The tooling2is used as follows.

Initially, the pneumatic line4is not fastened to the device6. The endpiece43is in its retracted configuration. Thus, the stopper34is in its position farthest away from the cylinder. The stopper34is in its extended position. The arms26are in the open position.

The endpiece43is inserted in the duct48so as to pass through the zones50and52until it reaches the zone54. As shown inFIG. 7, the zone50then extends radially between the spacers30together with the cylinder and the arms26.

Once the endpiece43, and in particular the front edge of the gasket31, is facing the portion54of the duct, the arms26are moved towards the axis22and they are prevented from moving when in the closed position. In the present example, the arms carry at their free ends respective half-collars60suitable for being fastened to each other by means of bolt fasteners, each comprising in particular a respective screw portion63and a knob61acting as a nut and having the screw passing therethrough.

In the present example, each half-collar60presents an inside face65presenting a back-draft coming to bear against a corresponding draft face of the zone50. Co-operation between these two faces prevents the device from being withdrawn by sliding along the axis22. The free end of the duct48is in axial abutment against the yoke24. The device6is thus rigidly fastened to the duct48.

Thereafter the handles50of the capstan46are operated to turn the capstan and thus to cause the stopper34to slide towards the cylinder. This movement causes the gasket31to slide over the ramp face44, thereby deforming the gasket by increasing the diameter d of its distal end edge. The gasket ends up by bearing radially via said edge against the inside face of the zone54of the duct, thereby providing sealing between the stopper and the duct.

The pneumatic line4is then connected to the device6and it is possible to perform the necessary testing, in particular by using the pressure gauge16, which makes it possible visually to inspect the pressure inside the jettisoning circuit.

Because the capstan forms adjustable control means for varying the diameter of the gasket31, the endpiece can be fitted to ducts48of different diameters.

It should be observed that the fastening of the tooling6by means of arms takes place without the arms coming into contact with the two rings of the zone52carrying rivets.

As can be seen, the device can be fitted in releasable and removable manner to the outlet of the jettisoning circuit in order to shut it temporarily and observe the pressure therein during leak testing. It provides an easy connection with the jettisoning circuit, while avoiding any contact with the portions carrying the rivets. It allows for venting once testing has been performed.

Naturally, numerous modifications could be applied to the invention without going beyond the ambit thereof.

The gasket31could be of an annular shape that is not circular, such that the modifiable dimension need not necessarily be a diameter. The device of the invention is usable with other types of jettisoning circuit, in particular those without rivets.