Tow system for an aircraft and method of towing an aircraft

Abstract

The present application provides a towing system for an aircraft and a method for towing an aircraft. To avoid operator intervention in the direction control device (18) provided for the aircraft towing system (4), the system comprises a first towing cable (10a) comprising a front end (12a) connected to a towing vehicle (2) and a rear end (13a) connected to a first main landing gear (8a), a second towing cable (10b) comprising a front end (12b) connected to the vehicle and a rear end (13b) connected to a second main landing gear (8b), and a direction control device (18) connected to the front landing gear (6) and arranged between the first and second towing cables, the device comprising lateral direction control means having a first lateral end (30a) mounted on the first towing cable (10a) and a second lateral end (30b) mounted on the second towing cable (10b).

Description

Traction systems for aircraft and methods for traction of aircraft Technical Field

[0001] This invention relates to the field of aircraft traction, particularly aircraft traction following anomalies such as runway deviation. In such cases, a specific traction system, also known as a rig, is typically required to detach the aircraft from the mud.

[0002] This invention is applicable to the towing of commercial and military aircraft. Background Technology

[0003] Aircraft traction systems typically include slings that allow traction of the main landing gear. These slings are usually supplemented with devices connected to the nose landing gear and positioned between the slings for controlling the aircraft's orientation. This orientation control device is operated by the operator, who adjusts the orientation of the nose landing gear wheels based on the direction of traction applied to the aircraft by the traction vehicle via the slings.

[0004] By doing so, the operator positioned between the tow lines faces the risk associated with the potential breakage of one of the components involved in the movement of the aircraft—such as cables, hooks, or even ropes.

[0005] Therefore, the existing design needs to be optimized to reduce the potential risks to people in the area between the tensioned cables during the aircraft's traction. Summary of the Invention

[0006] To meet this need, the subject of this invention is primarily a system for towing an aircraft, the system for connecting the aircraft to at least one towing vehicle, the system comprising:

[0007] - A first traction cable, the first traction cable including a front end for connection to the at least one towing vehicle and a rear end for connection to a first main landing gear located on a first side of the aircraft;

[0008] - A second traction cable having the same length as the first traction cable, the second traction cable including a front end for connection to the at least one towing vehicle and a rear end for connection to a second main landing gear located on a second side of the aircraft opposite to the first side; and

[0009] - A device for controlling the direction of the aircraft, which is connected to the nose landing gear of the aircraft and is located between the first tow cable and the second tow cable.

[0010] According to the present invention, the direction control device includes:

[0011] - A central connecting device for connection to the nose landing gear, the central connecting device having a rear end for connection to the nose landing gear;

[0012] – A lateral direction control device, the lateral direction control device being fixed to a central connecting device, and the lateral device having a first lateral end mounted on a first traction cable and a second lateral end mounted on a second traction cable opposite to the first lateral end.

[0013] By connecting the lateral end of the lateral directional control device to the traction cable, an automatic and permanent mechanical link is established between the direction of the nose landing gear and the direction of the traction force applied to the cable. In other words, it is these same traction cables that automatically control the devices used to control the aircraft's direction, eliminating the need for an operator to be present in the area near the cables. Consequently, the associated risks disappear.

[0014] The present invention preferably provides at least one of the following optional features, which may be used alone or in combination.

[0015] The first lateral end and the second lateral end are mounted to slide along their respective cables.

[0016] Each of the first lateral end and the second lateral end has a pulley for receiving the associated cable.

[0017] Each of the first lateral end and the second lateral end is equipped with a guide that allows the associated cable to remain in contact with the pulley.

[0018] The central connecting device includes a longitudinal rod, and the lateral direction control device includes a transverse rod fixed to the longitudinal rod by means of a fixing device, wherein the longitudinal rod and the lateral rod are preferably oriented substantially orthogonally relative to each other.

[0019] The central connecting device includes a safety device configured to break when the lateral force transmitted to the central connecting device by the lateral direction control device exceeds a predetermined maximum value.

[0020] The rear end of the central connecting device includes a connector for connection to the nose landing gear, the connector being configured to prevent the central connecting device from rotating relative to the nose landing gear about its longitudinal axis.

[0021] Each of the first and second traction cables is equipped with a device for measuring the traction force in the cable, preferably a force gauge, and the two devices are independent of each other.

[0022] Each of the first and second traction cables is equipped with a connector at its rear end, the connector being configured to slide along a connecting strip for traveling around the axis of the associated main landing gear on either side of the leg.

[0023] The traction system includes a landing gear wheel protection device arranged around the connecting belt.

[0024] The traction system includes a mechanical coupling device located between at least two independent legs of the same main landing gear.

[0025] Another subject of the present invention is a method for towing an aircraft using such a system, the method comprising the following steps:

[0026] – Connect the first traction cable and the second traction cable to the towing vehicle and to the first main landing gear and the second main landing gear, and connect the direction control device to the front landing gear and to the first traction cable and the second traction cable;

[0027] - The aircraft is towed by the movement of the towing vehicle as follows: during this towing, the direction control device is oriented according to the force applied to the first lateral end and the second lateral end of the lateral direction control device by the first traction cable and the second traction cable.

[0028] Other advantages and features of the invention will become apparent from the following non-limiting detailed description. Attached Figure Description

[0029] This description will be given with reference to the accompanying drawings, in which:

[0030] - Figure 1 shows a schematic side view of an aircraft towing operation using the towing system according to the present invention;

[0031] Figure 2 shows a plan view of the traction system according to a preferred embodiment of the present invention;

[0032] - Figure 2a shows a plan view of a portion of the traction system shown in the previous figure;

[0033] - Figure 3 shows a plan view of another part of the traction system shown in Figure 2;

[0034] - Figure 4 is a cross-sectional view taken along line IV-IV in Figure 3;

[0035] - Figure 5 is a schematic perspective view of the part of the aircraft's nose landing gear to which the traction system is connected;

[0036] - Figure 6 is a perspective view of the part of the traction system that is connected to the front landing gear;

[0037] - Figure 7 is a perspective view of the connecting strap used to ensure the connection between the cable and the main landing gear;

[0038] - Figure 8 is a perspective view similar to Figure 7, in which the connecting belt is equipped with a main landing gear wheel protection device;

[0039] - Figure 9 shows a perspective view of the traction system that allows the independent legs of the same main landing gear to be mechanically connected;

[0040] Figure 10 is a plan view similar to Figure 2, showing the configuration at the beginning of towing the aircraft, where the nose landing gear is tilted to the left; and

[0041] - Figure 11 is a plan view similar to Figure 2 of the configuration of the aircraft being towed during a turn performed by a towing vehicle. Detailed Implementation

[0042] Referring first to Figure 1, the operation of towing the aircraft 1 using the traction system 4 and the towing vehicle 2 according to the invention is shown. The traction system 4 is positioned at the rear of the towing vehicle 2 between the aircraft's different landing gears—that is, the front landing gear 6 designed to control the aircraft's taxiing direction and the two main landing gears 8a, 8b located behind the front landing gear 6.

[0043] The traction system 4 is preferably configured to ensure the recovery of an aircraft, for example, from mud after runway deviation. However, other applications are also possible, such as normal traction operations on hard ground.

[0044] Referring now to Figure 2, which shows the design of a traction system 4 according to a preferred embodiment of the invention, the system 4 is shown during a traction operation of the aircraft 1, for example, after runway deviation.

[0045] System 4 firstly includes a first traction cable 10a in the form of a cable, chain, belt, or any equivalent element. This first traction cable 10a includes a front end 12a for connection to the towing vehicle 2 and a rear end 13a for connection to the main landing gear 8a located on a first side of the aircraft. This first side corresponds to the right side when viewed forward along the aircraft's direction of travel 14 during a haul-out operation from the mud.

[0046] Similarly, a second traction cable 10b is provided, having the same length as the first traction cable 10a and also in the form of a cable, chain, belt, or any equivalent element. This second traction cable 10b includes a front end 12a for connection to the towing vehicle 2 and a rear end 13b for connection to the main landing gear 8b located on the second side of the aircraft. When viewed forward along the aircraft's direction of travel 14, this second side corresponds to the left side, opposite to the first side.

[0047] In this embodiment, the two tow cables 10a and 10b are mounted to the same towing vehicle 2 (or, if appropriate, to two towing vehicles), and preferably the two tow cables 10a and 10b remain independent of each other. In practice, it is not preferable to arrange the two cables 10a and 10b together at their front ends 12a and 12b, nor is it preferable to arrange the two cables 10a and 10b to slide along the same pulley fixed to the towing vehicle 2. This type of configuration can effectively lead to undesirable pivoting of the aircraft around the main landing gear, which is fixed and embedded in the ground.

[0048] Therefore, each front end 12a, 12b is preferably equipped with its own connector—such as a hook—which is mounted on a complementary component mounted on the traction vehicle 2. According to a contemplated alternative, two traction vehicles are provided, each dedicated to traction of one of the two cables 10a, 10b. In this case, the forward movement and direction of the two vehicles must be synchronized.

[0049] To ensure the balance of forces transmitted by the two cables, each of the two cables is equipped with a separate device 16 for measuring the traction force in the relevant cable. These devices 16, preferably in the form of a dynamometer or any other equivalent device, ensure not only that the traction forces transmitted by the two cables are relatively balanced, but also that the forces applied to the two main landing gears 8a, 8b do not exceed limits that could damage the landing gears or cause the cables to break.

[0050] The two cables of system 4 are supplemented with a device for controlling the direction of the aircraft, the device 18 being disposed between the two cables 10a and 10b. The device 18 first includes a central connecting device for connection to the nose landing gear 6, the central connecting device being formed by, for example, a longitudinal rod of a tow bar, the rear end 22 of which is used to connect to the nose landing gear 6.

[0051] At the front end of the longitudinal rod 20, the direction control device 18 includes a lateral direction control device formed by a transverse rod. As shown in FIG2a, the two rods 20, 24 are fixed to each other by a fixing device 26, and the two rods 20, 24 are oriented substantially orthogonally relative to each other. Alternatively, the transverse rod 24 may be a V-shaped structure, wherein the tip of the V is fixed to the longitudinal rod 20. Any other form that is symmetrical about the intermediate vertical longitudinal plane of the device 18 is also conceivable. The angle formed between the longitudinal rod 20 and the lateral direction control device remains fixed. Furthermore, without departing from the scope of the invention, the connection of the lateral direction control device to the longitudinal rod 20 may be made at a point other than its front end.

[0052] Preferably, the direction control device 18 is mounted on a height-adjustable wheel to support the direction control device 18 on the ground. Furthermore, each of the two rods 20, 24 is preferably adjustable in length to accommodate the length of the cable and the angle of the V formed by the cable.

[0053] One of the specific features of the invention is that the direction control device 18 is controlled by cables 10a and 10b. For this purpose, a first lateral end 30a of the transverse bar 24 is mounted on the first traction cable 10a between the front end 12a and the rear end 13a, and similarly, a second lateral end 30b is mounted on the second traction cable 10b between the front end 12b and the rear end 13b, opposite to the first lateral end 30a.

[0054] Therefore, an automatic and permanent mechanical connection is achieved between the direction of the nose landing gear 6 and the direction of the traction force applied to the cables 10a and 10b. In fact, it is the orientation of these same cable automatic control directional control devices 18 that eliminates the need for an operator to appear in the danger zone between the cables.

[0055] As a reference, it should be noted that the lateral ends 30a and 30b can be connected to cables 10a and 10b in different ways, for example, by fixing the lateral ends 30a and 30b to cables 10a and 10b at fixed symmetrical points on the two cables.

[0056] Referring now to Figures 3 and 4, the connection characteristics between the second lateral end 30b and the second traction cable 10b are shown. It should be understood that the same connection is provided between the first lateral end 30a and the first traction cable 10a.

[0057] The lateral end 30b supports a pulley 34 or any other similar device, the groove 36 of which receives the cable 10b. By means of this mounting, the lateral end 30b is thus mounted to slide along the cable 10b. Furthermore, in order to keep the cable 10b in the groove 36 even when the cable is no longer under tension, the lateral end 30b is equipped with a guide 40, the guide 40 being configured such that the cable remains in contact with the pulley 34 and is held between the bottom of the groove 36 and the guide 40. The guide 40 supported by the lateral end 30b is adjustable so that the cable 10b is introduced into the groove 36 during the installation of the device 18 prior to the aircraft's traction.

[0058] Referring now to Figures 5 and 6, the nose landing gear 6 is configured such that it has an elongated connecting member 44 extending along a transverse axis 46 parallel to the axis near the shaft 42. The elongated connecting member 44 is configured to mate with a connecting connector 48 engaged at the rear end 22 of the longitudinal rod 20. This connector 48 has a recess 50 that has a form complementary to that of the member 44 and extends along the same transverse axis 46. Therefore, once connected, the elongated connecting member 44 and the recess 50 inhibit rotation of the device 18 about the longitudinal axis 52 of the rod 20, but allow rotation of the device 18 about the transverse axis 46 of the connection between the device 18 and the nose landing gear 6.

[0059] Still at the rear end 22 of the longitudinal rod 20, this end includes a safety device 56 disposed between the connecting connector 48 and another portion of the rod 20. The safety device 56 is configured to break when the lateral force transmitted from the transverse rod 24 to the longitudinal rod 20 exceeds a predetermined maximum value. The safety device 56 is formed, for example, by standard gauged shear bolts 58 arranged vertically and passing through the connector 48 and the other portion of the rod 20. This particular feature allows for the avoidance of introducing forces that could damage the nose landing gear 6 into the nose landing gear 6, especially at the start of traction—in which case the landing gear takes a direction requiring strong straightening. Without departing from the scope of the invention, the safety device 56 may be located at any other position on the rod 20.

[0060] Referring now to Figures 7 and 8, a portion of the second main landing gear 8b is shown, illustrating a leg 60 supporting a shaft 42. A connecting strap 62 passes around the shaft 42 on either side of the leg 60 by forming a loop 64 through which a hook-shaped connector 66, secured to the rear end 13b of the second traction cable 10b, passes. This connector 66 is designed to slide along the connecting strap 62 to permanently balance the force transmitted by the portion of the strap on one side of the leg 60 with the force transmitted by the portion of the strap on the opposite side of the leg 60.

[0061] Assuming that the angles of these belt sections vary with the traction direction applied by cable 10b, there is a risk that the wheel 70 of landing gear 8b may come into contact with the connecting belt 62. To avoid any risk of damage, these belt sections are surrounded by a wheel protection device 72 shown in Figure 8. This device 72 may be in the form of, for example, a flexible or semi-rigid tube that is capable of rotating about the belt section supporting the tube by being driven by the contacting wheel.

[0062] It is clear that this connecting belt and its wheel protection device can be implemented in the same or similar manner on another main landing gear 8a.

[0063] Finally, it should be noted that, referring to Figure 9, when the main landing gear comprises several independent legs 60, each leg is controlled by a different control system and supports its own axle 42, and mechanical coupling devices are preferably provided between these legs 60. More specifically, mechanical coupling devices 78 are provided for each group of two independent legs 60 that are directly continuous in the same landing gear, in order to better distribute the traction force introduced into the landing gear by the index. In the example shown in Figure 9, which includes three legs, two coupling devices 78 are provided, each coupling device 78 in the form of a band surrounding two directly continuous legs 60.

[0064] In order to use the towing vehicle 2 and the towing system 4—such as the towing system 4 just described—to perform towing of the aircraft, the ends of cables 10a and 10b are first connected, as well as the directional control device 18 is connected to the nose landing gear 6 and the cables.

[0065] Next, the towing step, schematically shown in Figure 2, is achieved by the movement of the towing vehicle 2 in a forward direction 14 corresponding to the flight direction of the aircraft. As previously mentioned, during this step, the direction control device 18 is oriented according to the forces applied to the first lateral ends 30a and 30b of the transverse bar 24 by the first traction cable 10a and the second traction cable 10b. In particular, when the towing vehicle 2 maintains a straight forward direction, the two cables 10a, 10b remain symmetrical and apply lateral forces of similar intensity to the opposite ends 30a, 30b of the transverse bar 24. Therefore, the longitudinal bar 20 remains advantageously parallel to the forward direction of the towing vehicle 2, which allows for optimal orientation of the nose landing gear 6 during towing.

[0066] Figure 10 shows the configuration at the start of traction for the aircraft, which has the following specific feature: the nose landing gear 6 is tilted relative to the direction in which the aircraft should be tractioned. In this example, the nose landing gear 6 is tilted to the left. After the traction system 4 is assembled, the forward movement of the traction vehicle 2 causes the first traction cable 10a to be taut before the second traction cable 10b. This tension on the cable 10a induces a lateral force on the transverse bar 24 that tends to move the transverse bar 24 to the right, thereby gradually straightening the direction of the device 18.

[0067] Figure 11 illustrates another traction configuration observed during a left turn performed by the towing vehicle 2. In this hypothetical scenario, the first traction cable 10a, located on the outer side relative to the turning direction, remains under tension, while the second traction cable 10b on the inner side is slack. Therefore, a lateral force is transmitted to the first lateral end 30a of the transverse bar 24, while no opposing force is generated at the second lateral end 30b. Consequently, the steering control device 18 is forced to pivot to the left, allowing a direction substantially similar to that of the vehicle 2 to be applied to the forward landing gear 6 at any point during the turn.

[0068] The towing operation is preferably performed with the nose landing gear directional system deactivated—allowing the nose landing gear directional system to rotate freely and thus making it easily controllable by the device 18 of the present invention. In practice, during towing operations for pulling from mud, the aircraft may not be powered, resulting in electrical, hydraulic, and other such losses.

[0069] Obviously, those skilled in the art can make various modifications to the invention that has just been described by way of non-limiting example only, and the scope of the invention is defined by the appended claims.

Claims

1. A traction system (4) for an aircraft, the traction system (4) for connecting the aircraft (1) to at least one traction vehicle (2), the traction system comprising: A first traction cable (10a) comprising a front end (12a) for connection to the at least one towing vehicle (2) and a rear end (13a) for connection to a first main landing gear (8a) located on a first side of the aircraft; a second traction cable (10b) having the same length as the first traction cable, comprising a front end (12b) for connection to the at least one towing vehicle (2) and a rear end (13b) for connection to a second main landing gear (8b) located on a second side of the aircraft opposite to the first side; and a direction control device (18) for controlling the direction of the aircraft. For connection to the nose landing gear (6) of the aircraft, and the directional control device (18) is disposed between the first traction cable (10a) and the second traction cable (10b), wherein the directional control device (18) includes: a central connecting device for connection to the nose landing gear (6), the central connecting device having a rear end (22) for connection to the nose landing gear (6); a lateral directional control device fixed to the central connecting device, and the lateral directional control device having a first lateral end (30a) mounted on the first traction cable (10a) and a second lateral end (30b) mounted on the second traction cable (10b) opposite to the first lateral end (30a).

2. The traction system according to claim 1, wherein, The first lateral end (30a) and the second lateral end (30b) are mounted to slide along their respective cables (10a, 10b).

3. The traction system according to claim 2, wherein, Each of the first lateral end (30a) and the second lateral end (30b) has a pulley (34) for receiving the associated cable.

4. The traction system according to claim 3, wherein, Each of the first lateral end (30a) and the second lateral end (30b) is equipped with a guide (40) that enables the associated cable to remain in contact with the pulley (34).

5. The traction system according to any one of claims 1 to 4, wherein, The central connecting device includes a longitudinal rod (20), and the lateral direction control device includes a transverse rod (24) fixed to the longitudinal rod (20) by means of a fixing device (26).

6. The traction system according to claim 5, wherein, The longitudinal bar (20) and the transverse bar (24) are oriented substantially orthogonally to each other.

7. The traction system according to any one of claims 1 to 4, wherein, The central connecting device includes a safety device (56) configured to break when the lateral force transmitted to the central connecting device by the lateral direction control device exceeds a predetermined maximum value.

8. The traction system according to any one of claims 1 to 4, wherein, The rear end (22) of the central connecting device includes a connector (48) for connection to the front landing gear (6), the connector (48) being configured to suppress rotation of the central connecting device about its longitudinal axis (52) relative to the front landing gear (6).

9. The traction system according to any one of claims 1 to 4, wherein, Each of the first traction cable (10a) and the second traction cable (10b) is equipped with a device (16) for measuring the traction force in the respective cable, and the two devices (16) are independent of each other.

10. The traction system according to claim 9, wherein, The device (16) used to measure the traction force in the corresponding cable is a force gauge.

11. The traction system according to any one of claims 1 to 4, wherein, The rear ends (13a, 13b) of each of the first traction cable (10a) and the second traction cable (10b) are equipped with connectors (66) configured to slide along a connecting band (62) for passing around the axis (42) of the associated main landing gear on either side of the leg (60) of the main landing gear.

12. The traction system according to claim 11, wherein, The traction system includes a landing gear wheel protection device (72) which is arranged around the connecting belt (62).

13. The traction system according to any one of claims 1 to 4, wherein, The traction system includes a mechanical coupling device (78) located between at least two independent legs (60) of the same main landing gear.

14. A method for towing an aircraft (1) using a system (4) according to any one of claims 1 to 13, wherein, The method includes the following steps: connecting the first traction cable (10a) and the second traction cable (10b) to the towing vehicle (2) and to the first main landing gear (8a) and the second main landing gear (8b), and connecting the directional control device (18) to the nose landing gear (6) and to the first traction cable (10a) and the second traction cable (10b); traction of the aircraft by the movement of the towing vehicle (2) is performed as follows: during traction, the directional control device (18) is oriented according to the force applied by the first traction cable (10a) and the second traction cable (10b) to the first lateral end (30a) and the second lateral end (30b) of the lateral directional control device.

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