WO2015173492A1

WO2015173492A1 - Installation for mooring a lighter-than-air aircraft

Info

Publication number: WO2015173492A1
Application number: PCT/FR2015/051196
Authority: WO
Inventors: Baptiste Regas; Adrien REGAS; Olivier Jozan; Guillaume DESROCQUES
Original assignee: A-Nte (Aero-Nautic Technology & Engineering)
Priority date: 2014-05-13
Filing date: 2015-05-05
Publication date: 2015-11-19
Also published as: FR3021032B1; FR3021032A1

Abstract

The invention relates to an installation (1) for mooring a lighter-than-air aircraft (100), comprising a platform (2) mounted such that it rotates about a vertical axis (Z), a boom (5) extending horizontally from the platform, and a pulley (6) for guiding a cable (4) mooring the lighter-than-air aircraft. The installation (1) also comprises a pulley support (7) which is mobile in relation to the boom, and an elastic body (9) that connects said pulley support to the boom.

Description

Installation for retaining an aerostat

TECHNICAL AREA

The present invention relates to an installation for retaining an aerostat.

STATE OF THE PRIOR ART

More particularly, the invention relates to an installation for retaining an aerostat comprising:

a platform rotatably mounted about a vertical axis, said platform comprising a winch for winding and unrolling a cable to which said aerostat is attached,

a boom that extends horizontally from the platform, and

- A pulley adapted to guide the cable from the winch.

Such an installation holds the aerostat away from the ground and naturally moves in the direction of the wind

Installations of this type are known. Document US 4,421,286 describes such an installation whose boom is telescopic to adapt to aerostats of different sizes.

SUMMARY OF THE INVENTION

The present invention aims to improve the facilities of this type, especially to better adapt to the wind.

For this purpose, an installation of the aforementioned type is characterized in that it further comprises:

a pulley support for supporting the pulley, said pulley support being movable relative to the boom, and

an elastic member which connects said pulley support to the boom, the pulley support and the resilient member being arranged to move the pulley and reduce a transverse moment applied to the platform.

Thanks to these provisions, the tension of the cable after the pulley and towards the aerostat, generated by the force of the wind, naturally moves the pulley support. The moment or transverse torque applied to the platform by the wind (or any other external action on the aerostat or the installation) is then reduced. The size of the boom, the pivot connection between the platform and a support can be reduced. More generally, the size and cost of the installation can be reduced.

In addition, voltage variations and / or cable length can be absorbed. These variations are penalizing for the installation (the pivot connection, the winch), but also for the aerostat.

In addition, the installation is a mechanical system that consumes no energy and is very reliable.

In various embodiments of the installation according to the invention, one may optionally also resort to one and / or the other of the following provisions.

According to one aspect of the invention, the installation further comprises a compensating assembly to compensate for variations in voltage or cable length.

According to one aspect of the invention, the compensation assembly is integrated in the pulley support.

According to one aspect of the invention, the compensation assembly comprises a compensating pulley mounted movably and which is biased by a return spring, and the cable passes successively by the pulleys for storing a length of cable.

According to one aspect of the invention, the compensation assembly comprises at least two movably mounted compensation pulleys each of which is urged by a return spring which moves them away from each other by relative to a median position of said compensating pulleys, and the cable passes successively by the pulleys to store a length of cable.

According to one aspect of the invention, the installation further comprises at least one stop to limit a permissible displacement of the pulley support relative to the boom.

According to one aspect of the invention, the stop is adjustable to modify the permissible displacement of the pulley support.

According to one aspect of the invention, the pulley support is connected to the boom by a sliding connection for sliding along the boom, and the resilient member urges the pulley support towards one end of the boom opposite the the platform.

According to one aspect of the invention, the pulley support is secured to an arm pivotally mounted relative to the boom, and the resilient member urges the arm towards the boom.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the invention will become apparent from the following description of two embodiments, given by way of non-limiting examples, with reference to the accompanying drawings.

On the drawings:

- Figure 1 is a side view of an installation according to a first embodiment of the invention;

- Figure 2 is a top view of the installation of Figure 1;

FIG. 3 is a side view of an installation according to a second embodiment of the invention; and

- Figure 4 is a schematic view of a pulley support comprising a compensation assembly. In the different figures, the same reference numerals designate identical or similar elements.

DETAILED DESCRIPTION OF EMBODIMENTS

In this description, the terms

"Upper" or "upwards" and "lower" or "downwards" are used relative to the vertical direction Z, upwards, perpendicular to the longitudinal direction X and the transverse direction Y.

Figure 1 shows an installation 1 for retaining an aerostat 100.

The balloon 100 is a tethered balloon or an airship that is connected to the facility to hold it in a stationary or near-stationary position and at a predetermined altitude above the ground, or to bring it close to the ground just above the installation. The term aerostat means a balloon comprising an envelope 101 which contains a gas less dense than air, and possibly a nacelle 102 for loading equipment or passengers.

The landing of the aerostat 100 is done by means of at least one cable 4 which connects the aerostat (its nacelle 102) to a support 11 (ground or any other support).

The installation 1 comprises, as is known, a platform 2 rotatably mounted about a vertical axis Z, by a pivot connection 10 between the platform 2 and a support 11,

a boom 5 which extends substantially horizontally from the platform 2 in a longitudinal direction X, and

a pulley 6 adapted to guide the cable 4 and deflect it from said longitudinal direction to direct it towards the aerostat 100.

Indeed, the cable 4 comprises a first strand ₁ between the platform 2 and the pulley 6 of direction substantially identical to that of the boom 5, and a second strand 4 ₂ between the pulley 6 and the balloon 100 direction inclined relative to the longitudinal direction X, this direction at an angle with the longitudinal direction X.

The support 11 is for example the ground or any other intermediate means, such as a rolling or non-rolling vehicle adapted to support the installation and itself possibly anchored to the ground. For example, the vehicle can be a pickup, a truck, a boat, a ship.

The platform 2 comprising a winch 3 for winding and unrolling the cable 4 at the end of which is attached the aerostat 100.

The cable 4 extends from the winch 3 to the pulley 6 situated at a point P distant from the vertical axis Z, and up to the aerostat 100. The point P is at a distance L from this vertical axis Z .

The support 11 and the aerostat 100 may undergo external forces and / or uncontrolled movements (wind, waves, etc.). The combination of these forces and / or movements generate a tension T in the connecting cable between the installation 1 and the aerostat 100. In the remainder of the present description, we consider for simplification explanations only the case of a wind action V.

A wind V applies a force on the envelope 101 of the aerostat which causes a tensile tension T in the cable 4. A change of direction of the wind V in a horizontal plane XY causes a moment or vertical torque Mz on the platform 2 a distance component L and a tangential component Tt of the voltage T. Said tangential component is a component of the voltage T which is tangent to the horizontal circle passing through the point P in said horizontal plane (see FIG. 2, considering the pulley support 7 fixed). Thus, the vertical moment Mz is equal to:

Mz = L.Tt = L. T. cos (a). sin (γ) or

is the angle (elevation angle) that the cable 4 makes with respect to the horizontal plane XY,

γ is the lateral angle made by the cable 4 with respect to the vertical plane XZ, the direction X being the direction of the boom 5,

T is the tension of the cable, and

L is the distance between the vertical axis Z is the pulley 6 (in the horizontal plane XY).

This vertical moment Mz causes rotation of the platform 2 with respect to the ground around the vertical axis Z, until the alignment of the boom 5 in the direction (in a horizontal plane) of the aerostat 100. The boom 5 is thus naturally oriented in the direction of the aerostat.

As soon as the boom is correctly oriented, this vertical moment Mz becomes zero because the lateral angle γ becomes zero (γ = 0).

The tension T also causes a moment or transverse torque My on the platform 2 which tends to tilt around the transverse axis of rotation Y. The pivot connection 10 which supports the platform 2 must be dimensioned to withstand extreme tension T , corresponding to a maximum of admissible wind.

Thus, with the same notations as before, the transverse moment My is equal to:

My = L.Tz = L. T. sin (a). cos (γ),

Tz being the vertical component of the voltage T (projection on the direction of vertical axis Z).

For simplicity, it will be assumed later that the boom 5 is oriented towards the aerostat 100, and therefore: cos (γ) = 1.

Usually, a second cable connects the nose 103 of the aerostat 100 to the installation 1. In this case, the installation 1 also comprises a mast which extends vertically upwards from the platform 2 to guide up to a second point said second cable and moor the nose 103 of the aerostat at the upper end of said mast. The aerostat in the landing position is then retained by the two cables, at two points: at its nose and the nacelle. The height of the mast and the length of the boom are sometimes adjustable to accommodate different sizes of aerostat, as described in US 4,421,286.

The installation 1 of the present invention improves the known installations. As shown in the figures, it further comprises:

a pulley support 7 adapted to support the pulley, said pulley support 7 being movable relative to the boom 5, and

an elastic member 9 which connects said pulley support 7 to the boom 5.

Thanks to these arrangements, the pulley support 7 can move towards the vertical axis Z, but it is returned to an equilibrium position distant from this vertical axis by the elastic member 9.

The pulley support 7 is for example a clevis or U-shaped piece comprising a shaft on which the pulley 6 is rotatably mounted.

The elastic member 9 is for example a spring whose one end is integral with the pulley support 7 and a second end 5a is integral with the boom 5. This elastic member 9 is adapted to exert a restoring force on the pulley support 9 and to give it a position of equilibrium as a function of the tension T experienced by the cable 4. The spring may be of any type, linear or otherwise, with a damping component or without. This spring is for example a helical spring, a leaf spring, a metal spring or elastomer or any other material.

Optionally, the elastic member 9 may comprise in addition to a spring, a damper mounted in parallel with said spring; this damper being a separate element and separated from the spring. The damper can be of any type, linear or non-linear, and for example a hydraulic damper, pneumatic, or other.

Optionally, the elastic member 9 can be constructed with a magnetic or electrical system, controlled or not, the control giving equivalence the stiffness characteristic of the spring and possibly the damping characteristic of the damper. According to a first embodiment of the invention presented in FIGS. 1 and 2, the pulley support 7 is connected to the boom 5 by a sliding connection 8. The pulley support 7 slides on the boom in the horizontal direction X so that the distance L between the vertical axis Z and the point P (axis of rotation of the pulley 6) is modifiable and simply changes as a function of the tension T of the cable 4.

The elastic member 9 connects said pulley support 7 to the boom 5, and for example urges the pulley support 7 towards an end 5a of the boom located opposite the platform 2 (away from the vertical axis Z ).

In such a case, the equilibrium equations of the pulley support 7 (forces and moments) make it possible to determine the transverse momentum My, and we obtain:

My = L ₀ .sin (CC) .T - (l-cos (OC)) .sin (CC) / kT ² where

L ₀ is the equilibrium distance of the pulley 6 on the boom 5, and

k is the stiffness of the elastic member (in N / m).

The first term (L ₀ .sin (CC)) is equivalent to the expression previously obtained, the pulley 6 not being displaceable.

The second term ((1-cos (OC)) sin (OC) / kT ² ) is deduced from the first term. If the stiffness k of the elastic member 9 is very large, this second term becomes negligible.

The transverse moment My can therefore be reduced by this second term, in comparison with an installation without moving pulley.

The transverse moment My, for a voltage value T, can even be canceled for the following optimal stiffness value k ₀ :

k ₀ = (1-cos (a)). T / L ₀

More precisely :

1) If the voltage T is within the following range:

0 <T <kL ₀ / (1-cos (a)),

then the pulley support 7 and the pulley 6 move to have an equilibrium position located between the end of the boom 5a and the vertical axis Z; the higher the tension T, the more these elements will move towards the vertical axis Z, and the transverse moment My will be reduced compared to an installation without the provisions of the invention (pulley 6 mobile).

If the tension T increases in the first half of the interval, the transverse momentum My increases less rapidly than the law L ₀ .sin (CC) .T (first term), because of the second term.

If the voltage T is T ₀ = 2.kL ₀ / (l-cos (CC)), the transverse momentum My is stabilized at a maximum value M ₀ .

Consequently, the transverse moment My is limited, which avoids platform tilting and / or damage to its pivot connection 10 of vertical axis Z.

If the tension T increases in the second half of the interval, the transverse momentum My decreases until it becomes zero.

2) If the voltage T is greater than or equal to the limit voltage T ₀ = 2.kL ₀ / (1-cos (a)), then the pulley support 7 and the pulley 6 are positioned on the vertical axis Z, and the transverse moment My is zero. This prevents a tilting and / or damage to the platform in extreme wind conditions.

Thanks to these arrangements, the pivot connection 10 can be dimensioned in a reduced manner and thus be less expensive.

Consequently, thanks to the elements of the installation 1 according to the invention, the platform 2 undergoes reduced forces (moments). In addition, the variations of these efforts can also be reduced and amortized. Platform 2 thus undergoes less static effort and less dynamic effort.

According to a second embodiment of the invention presented in FIG. 3, the pulley support 7 is integral with an arm 12 that extends from a hinge 13 (pivot connection) located near the platform 2 or on the platform 2. The arm 13 and the pulley support 7 are thus able to pivot around the hinge 11.

The elastic member 9 connects the pulley support 7 or the arm 13 to the boom 5, and urges the arm 12 and the pulley support 7 towards the boom 5 in rotation.

In this embodiment, the rotation of the arm 12 also changes the distance L between the vertical axis Z and the pulley 6.

The equilibrium equations of the pulley support 7 (forces and moments) make it possible to determine the transverse momentum My, and we obtain:

My = L12. T. sin (OC- β)

or

L12 is the length of the arm 12 or distance between the pulley support 7 and the articulation 13, and L ₁₂ = L / cos (β),

is the angle between the cable 4 and the longitudinal direction X, and

β is the angle between the arm 12 and the longitudinal direction X. Thus, when the difference (OC-β) is zero, the cable 4 and the arm 12 are aligned in the same direction, and the transverse moment My is zero.

In addition, the elastic member 9 recalls the arm 12 towards the boom 5, according to the following relationship:

An optimum stiffness value k ₀ for the stiffness of the elastic member can be determined by solving the two equations above.

The installation 1 of this second embodiment has the same effects: The increase of the voltage T reduces the length L and therefore the transverse moment My. The variations of the moment My are also relatively absorbed.

The various embodiments of the invention, it is possible to use stops to limit the displacement of the pulley support 7 between two stop positions (not shown) located along the length of the boom 5.

These abutment positions are optionally adjustable to adapt for example to the size of the aerostat, and therefore to a nominal value of voltage.

Optionally, the elastic member 9 is also adjustable: its stiffness k can be modified to adapt to the size of the balloon and / or external conditions (swell, wind).

The installation 1 may furthermore comprise a compensating assembly to compensate for variations in distance between the installation 1 and the aerostat 100. These variations also cause voltage variations T in the cable 4, which variations may be transient and abrupt. The compensation set thus allows:

or to release (or unwind) a length of cable, to limit the voltage in the second strand 4 ₂ of the cable 4 to a value below a maximum value, that is to say to release the second strand 4 ₂ too tight cable 4,

or to remove (or wind up) a length of cable, to limit the voltage in the second strand 4 ₂ of the cable 4 to a value above a minimum value, that is to say to keep the second strand 4 ₂ of the cable 4 under tension.

FIG. 4 gives an exemplary embodiment of such a compensation assembly integrated in the pulley support 7, said pulley support 7 being still mobile with respect to the boom 5, and connected thereto by an elastic member 9, whereby the transverse moment My applied to the platform 2 can be reduced.

Firstly, this pulley support 7 comprises for example:

an input pulley 6a which takes up the first strand ₁ of the cable, and

- An output pulley 6b which deflects the second strand 4 ₂ of the cable 4 to the aerostat; this output pulley 6b thus having the function of the pulley 6 of the embodiments presented above.

Secondly, the pulley support 7 comprises at least one compensation pulley 6i movably mounted relative to the pulley support 7, said compensating pulley 61 being also biased by a return spring 9i. The cable 4 passes through the pulleys (for example, the output pulley 6, the input pulley, and the compensation pulley).

Advantageously, the pulley support 7 comprises a plurality of compensation pulleys 6i, 6 ₂ (for example two or more than two) which are movably mounted in translation relative to said pulley support 7, each of these compensation pulleys being solicited by a return spring 9 _lr 9 ₂ to positions which distance them two by two from a median position. The whole is then able to store in a given space a longer cable length.

The cable 4 is engaged in the compensation assembly, and successively passes through the input pulley 6a, successively by the compensating pulleys 6i, 6 ₂ , for storing a length of cable, and by the output pulley 6b before to extend to the aerostat 100. The cable 4 thus makes several trips back and forth in the compensation assembly as in a hoist, but which here makes it possible to swallow lengths of cable or to release cable lengths while maintaining a tension thanks to the return springs.

The compensation assembly may comprise as many compensation pulleys as necessary, with identical return springs or with different stiffnesses. In addition, each compensation pulley can be equipped with a stop to adjust its allowable stroke. It is thus possible to size the races of the compensation pulleys and the values of the stiffness of the return springs in order to obtain a predetermined characteristic of lengths swallowed by the cable as a function of a tension. Each of these races and / or stiffness is optionally adjustable to adapt to the size of the balloon and / or external conditions (swell, wind).

The compensation assembly thus makes it possible to absorb variations in cable length and / or voltage variations T in cable 4. It is thus advantageous to integrate this compensation assembly with the pulley support according to the invention for limit the variations of transverse moment My seen by the platform 2 in addition to the reduction of this transversal moment My seen by the platform 2.

Finally, the compensation assembly may optionally be integrated in the platform 2 and move the winch 3 on said platform in the longitudinal direction of the boom 5.

Claims

1. Installation (1) for retaining an aerostat (100) comprising:

a platform (2) rotatably mounted around a vertical axis (Z), said platform comprising a winch (3) for winding and unrolling a cable (4) to which said aerostat is attached,

a boom (5) extending substantially horizontally from the platform, and

a pulley (6) adapted to guide the cable coming from the winch,

said installation being characterized in that it further comprises:

a pulley support (7) for supporting the pulley, said pulley support being movable relative to the boom, and

an elastic member (9) which connects said pulley support to the boom,

the pulley support and the resilient member being arranged to move the pulley and reduce a transverse moment (My) applied to the platform (2).

The plant of claim 1, further comprising a compensation assembly for compensating for voltage or cable length variations.

3. The installation according to claim 2, wherein the compensation assembly is integrated in the pulley support (7).

4. The installation according to claim 2 or claim 3, wherein the compensation assembly comprises a compensating pulley (6i) movably mounted and which is biased by a return spring (9i), and the cable (4). passes successively by the pulleys for store a length of cable.

5. The installation according to claim 2 or claim 3, wherein the compensation assembly comprises at least two compensating pulleys (6i, 6 ₂ ) movably mounted and which are each biased by a return spring (9i, 9). ₂ ) which moves them away from one another relative to a median position of said compensating pulleys, and the cable (4) passes successively by the pulleys to store a length of cable.

6. The installation according to any one of claims 1 to 5, further comprising at least one stop to limit a permissible displacement of the pulley support (7) relative to the boom (5).

7. The installation of claim 6, wherein the stop is adjustable to change the allowable displacement of the pulley support (7).

8. The installation according to any one of claims 1 to 7, wherein the pulley support (7) is connected to the boom by a sliding connection for sliding along the boom, and the elastic member (9). urges the pulley support towards one end of the boom opposite the platform.

9. The installation according to any one of claims 1 to 7, wherein the pulley support (7) is integral with an arm (12) pivotally mounted relative to the boom, and the elastic member (9). apply the arm towards the boom.