An eyebolt mounting mechanism

Abstract

This invention relates to a shell (2) with an external fuel tank aerodynamic surface, at least one opening (3) with a gap on the shell (2), at least one reinforcement piece (4) mounted on the inner surface of the shell (2), at least one slot (5) located in the form of a cavity on the reinforcement piece (4) and accessible through the opening (3), at least one lateral wall (601 ) extending along each slot (5) and having a gear track on it, and at least one eyebolt (7), one end of which is compatible with the teeth on the lateral wall (601), thus mounted on the lateral wall (601), and the other end of which is attached to the aircraft.

Description

[0001] AN EYEBOLT MOUNTING MECHANISM

[0002] This invention relates to the installation of external fuel tanks in aircraft.

[0003] By means of the external fuel tanks (drop tanks) that can be mounted under the wing or on the fuselage of the aircraft, the duration of the aircraft's stay in the air is increased. The external fuel tank is attached to the aircraft by connecting the eyebolts in the external fuel tank to the hooks on the ejector release unit under the aircraft wing. There are eyebolt bearings under the place where the eyebolts are located on the inside of the external fuel tank. As the eyebolts are threaded and placed on the eyebolt bearings, the eyebolt bearings become worn and damaged. Eyebolts are standard parts and their material is generally steel. Aircraft structures are produced from aluminium instead of steel due to weight savings. Connecting the teeth of the steel eyebolt, which is a hard material, to the teeth on the external fuel tank made of aluminium, which is a softer material than steel, wears the eyebolt bearings on the external fuel tank, damaging its structural integrity. Special equipment is required to repair or replace the eyebolt bearings used for mounting to the aircraft body in external fuel tanks if they become damaged or unusable. In addition, operations are carried out on the tank structure and the systems within the tank structure, and long labour hours are spent. Since the external fuel tank consists of a single welded structure or is combined with many connectors, wear of the eyebolt bearings causes the entire structure to require maintenance.

[0004] In the United States patent document numbered US6491255B1 in the state of the art, it is mentioned that the mounting handles are threadedly connected to the molar blocks through the openings created in the outer layer and shell. Molar blocks are preferably formed from aluminium due to weight considerations. However, the mounting handles are made of steel material. A threaded insert and a mounting lug sleeve are screwed into the molar blocks and formed from steel to provide a steel-to-steel connection for the mounting lugs. Lightweight composition materials such as fibreglass composites are used to give strength and lightness to the central structure. By means of the eyebolt mounting mechanism developed with this invention, the material that is difficult to wear comes into contact with the eyebolt and the bearing element can be easily assembled / disassembled.

[0005] Another aim of this invention is to provide an eyebolt mounting mechanism that provides sealing for the fuel, does not affect aerodynamic friction, is durable, prevents damage to the structural parts inside the external fuel tank, can be easily maintained without any operation on the systems within the tank structure, and is easily accessible by the operator.

[0006] The eyebolt mounting mechanism defined in the first claim and the claims dependent on this claim, which is realised to achieve the aim of the invention, comprises an external fuel tank designed to be installed on the aircraft. There is a gap-shaped opening on the shell part of the external fuel tank, which is the aerodynamic surface in contact with the air. The reinforcement piece, which has a hollow-shaped slot on it and is mounted on the inside of the shell so that the slot can be accessed through the opening on the shell, allows the external fuel tank to be mounted on the aircraft. The reinforcement piece is connected to the shell from the part where the fuel is located, increasing the strength of that area while hanging the external fuel tank. Inside the slot, there is a lateral wall with a form-compatible surface with the lateral surfaces of the slot. By opening the teeth on the lateral walls, the eyebolt is rotated and attached to the lateral wall. Eyebolts are standard parts, some of which are threaded and some of which are hollow, and are fixed to the lateral wall by being rotated, and by inserting spaces into the hooks on the aircraft, they enable the external fuel tank to be mounted on the aircraft.

[0007] The eyebolt mounting mechanism of the invention comprises a base to which an eyebolt is attached to one side and which forms the base of the lateral wall in the slot so that it remains opposite the eyebolt when the eyebolt is attached. Flanges extending from the lateral walls to the outer surface of the shell surround the opening and prevent the leakage of fuel in the external fuel tank. The possibility of leakage from gaps arising from production tolerances under the flange is prevented by the gasket installed between the flange and the shell. The one-piece bearing element, consisting of flange, base and lateral wall, can be removably attached to the slot and the shell. In one embodiment of the invention, the eyebolt mounting mechanism comprises at least one screw and at least one nut connecting the base to the slot for mounting the bearing element to the slot. There are at least one screw and one nut on the base, but when there are no screws and nuts on the flanges, they can be placed as more than once. Thus, the bearing element can be prevented from rotating within the slot.

[0008] In one embodiment of the invention, the eyebolt mounting mechanism comprises a protrusion-shaped limiter that restricts the eyebolt from moving further within the bearing element by ensuring that there is a height greater than the height of the head of the screw in order to prevent it from hitting the screw while placing the eyebolt into the bearing element.

[0009] In one embodiment of the invention, the eyebolt mounting mechanism comprises a limiter that surrounds the intersection area of the base and the lateral wall, its height on the lateral wall being at least as high as the height of the screw head, and the annular space in the middle of the base being at least as much as the diameter of the screw head.

[0010] In one embodiment of the invention, the eyebolt mounting mechanism comprises a mounting region, which is the region around the opening between the reinforcement piece mounted on the inner surface of the shell where the fuel is located, and the flange mounted on the outer surface where the air flow contacts the shell.

[0011] In one embodiment of the invention, the eyebolt mounting mechanism comprises a bearing element with bevelled edges that are form-compatible with the opening edges, mounted on the outer surface of the mounting region, which is the region on the shell. In order to prevent fuel leakage by placing the bearing element in the mounting region, the part of the opening where the edges of the opening and the floor and lateral walls intersect, in contact with the opening, is produced in accordance with the form of the opening.

[0012] In one embodiment of the invention, the eyebolt mounting mechanism comprises a bevelled bearing element so that the eyebolt can be placed in a form -compliant manner to the inner part of the area where the flange and the lateral wall intersect and that there is no need to perform any work on the eyebolt.

[0013] In one embodiment of the invention, the eyebolt mounting mechanism comprises screws and nuts that enable the flanges, reinforcement piece and mounting region to be mechanically connected to each other, respectively, from outside to inside.

[0014] In one embodiment of the invention, the eyebolt mounting mechanism comprises a nut that is mounted on the reinforcement piece from the inside of the external fuel tank, is a sliding type so that the screw can be inserted from outside the shell and tightened with the nut and is in dome form to ensure sealing. The dome-shaped nut remains fixed by being attached to the reinforcement piece before the external fuel tank is completely closed and welded. The screw is attached from outside the tank after it is welded and clamped. For this reason, a sliding type nut is needed. The bearing elements are replaceable, so if something happens to one of them, a new one can be produced and replaced without the need for extra work. Thus, when the bearing element is replaced, the reinforcement piece remains in the external fuel tank and the connector holes on it remain as before and do not change. However, the connector holes drilled on the new bearing element to be installed may not be the same as the previous one and can be produced with a production tolerance of millimetres. The sliding type nut is attached to the reinforcement piece so that the screw can pass through two different holes. The dome-shaped nut plate provides sealing since it is both a closed structure and has a gasket within itself.

[0015] In an embodiment of the invention, the eyebolt mounting mechanism comprises a bearing element that is produced from the same material as the eyebolt, ensuring their wear is delayed and their strength is higher compared to each other.

[0016] In one embodiment of the invention, the eyebolt mounting mechanism comprises a flange that ensures minimising the friction force caused by air flow by means of its production in form compatible with the shell.

[0017] In one embodiment of the invention, the eyebolt mounting mechanism comprises a bearing element and eyebolt made of high-strength steel. In one embodiment of the invention, the eyebolt mounting mechanism comprises a bearing element that can be removed and installed on the slot and shell independently of each other. In case of mechanical damage to the bearing element, one can be replaced independently of the other. The flanges of the bearing element come under the piston and increase the material thickness there, thus providing additional strength to the reinforcement piece.

[0018] In one embodiment of the invention, the eyebolt mounting mechanism comprises a reinforcement piece that is attached to the shell from the inner part where the fuel is located, in a way that prevents damage to the shell by coming under the pistons in the release unit in the aircraft. The reinforcement piece is mounted to the shell from the inside by connecting it to the beams on the right and left. Mechanical fastening of the reinforcement piece is achieved with the screw-nut connection. The pistons apply high forces to the external fuel tank, separating the external fuel tank from the aircraft. There may be more than one slot on the reinforcement piece for mounting each bearing element. Each of the slots matches each opening on the shell.

[0019] In one embodiment of the invention, the eyebolt mounting mechanism comprises a hollow-shaped channel all around on the lateral wall to prevent damage to the bearing element while mounting the eyebolt to the bearing element. By means of the channel, the bevelled edge of the eyebolt enters the oval (radius) form of the channel and prevents damage to the lateral wall and the eyebolt when it contacts the limiter.

[0020] The eyebolt mounting mechanism realised to achieve the aim of this invention is shown in the attached figures, and of these figures;

[0021] Figure 1 - is the perspective view of the shell, bearing element, eyebolt and reinforcement piece.

[0022] Figure 2 - is the side view of screw, nut, reinforcement piece, shell and bearing element.

[0023] Figure 3 - is the side view of the bearing element. Figure 4 - is the top view of the eyebolt.

[0024] The parts in the figures are numbered one by one and the equivalents of these numbers are given below.

[0025] 1 . Eyebolt mounting mechanism

[0026] 2. Shell

[0027] 201 . Mounting region

[0028] 3. Opening

[0029] 4. Reinforcement piece

[0030] 5. Slot

[0031] 6. Bearing element

[0032] 601 . Lateral wall

[0033] 602. Base

[0034] 603. Flange

[0035] 7. Eyebolt

[0036] 8. Screw

[0037] 9. Nut

[0038] 10. Limiter

[0039] 1 1. Channel

[0040] Eyebolt mounting mechanism (1 ) comprises a shell (2) with an external fuel tank aerodynamic surface, at least one opening (3) with a gap on the shell (2), at least one reinforcement piece (4) mounted on the inner surface of the shell (2), at least one slot (5) located in the form of a cavity on the reinforcement piece (4) and accessible through the opening (3), at least one lateral wall (601 ) extending along each slot (5) and having a gear track on it, and at least one eyebolt (7), one end of which is compatible with the teeth on the lateral wall (601 ), thus mounted on the lateral wall (601 ), and the other end of which is attached to the aircraft.

[0041] Eyebolt mounting mechanism (1 ), which is the subject of the invention, comprises a base (602) opposite the eyebolt (7) and forming the base of the lateral wall (601 ), at least one flange (603) that extends from the lateral wall (601 ) to surround the opening (3) and is mounted on the outer surface of the shell (2), thus allowing almost complete fuel sealing, and the bearing element (6) that is removably attached to the slot (5) and the shell (2) and is formed by the lateral wall (601 ), base (602) and flange (603) being one piece (Figure - 1 , Figure - 2, Figure - 3).

[0042] There is a shell (2) belonging to the external fuel tank to be installed on the aircraft and exposed to air flow, and at least one opening (3), which is a hole on the shell (2). In order to mount the external fuel tank to the aircraft, the reinforcement piece (4) that provides increased mechanical strength is mounted internally on the shell (2). In this way, the shell (2) is prevented from being damaged when the entire fuel tank reinforcement piece (4) is attached to the aircraft. At least one slot (5) in the form of a cavity on the reinforcement piece (4) is located aligned with the opening (3). There is a lateral wall (601 ) that is compatible with the surface inside the slot (5) and extends along the side surfaces. By means of the thread paths opened inside the lateral walls (601 ), the eyebolt (7) can be attached to the lateral wall (601 ). A part of the eyebolt (7) has teeth that are compatible with the lateral walls (601 ), and a hole in one part allows the external fuel tank to be mounted by hooks on the aircraft.

[0043] There is a base (602) with a surface in the middle of the lateral walls (601 ) to form a hollow truncated cylindrical structure within the slot (5). In this way, the base (602) remains opposite the eyebolt (7) when the eyebolt (7) is mounted. By means of the flange (603) extending from the lateral walls (601 ) to surround the opening (3), a gasket can be installed between the shell (2) and the flange (603). By means of the gasket in the same form as the flange (603), fuel leakage is prevented. The bearing element (6), which is obtained by making the flange (603), base (602) and lateral walls (601 ) one piece, can be removably inserted into the shell (2) and / or slot (5) (Figure - 1 , Figure - 2, Figure - 3, Figure - 4).

[0044] In an embodiment of the invention, the eyebolt mounting mechanism (1 ) comprises at least one screw (8) and at least one nut (9) that enable mounting the base (602) to the slot (5). In this way, the bearing element (6) can be removably attached to the slot (5) in a form-compatible manner.

[0045] In an embodiment of the invention, the eyebolt mounting mechanism (1 ) comprises at least one limiter (10) located in the form of a protrusion on the inner surface of the bearing element (6) and ensuring that there is a distance between the base (602) and the eyebolt (7) greater than the head height of the screw (8). In this way, the eyebolt

[0046] (7) can be stopped from advancing within the lateral wall (601 ) without hitting the screw

[0047] (8).

[0048] In an embodiment of the invention, the eyebolt mounting mechanism (1 ) comprises a limiter (10) surrounding the intersection of the base (602) and the lateral wall (601 ). By surrounding the intersection of the base (602) and the lateral walls (601 ) in a ring shape, the limiter (10) stops the advancement of the eyebolt (7) on the lateral walls (601 ) before it hits the head of the screw (8), and allows the screw (8) to connect the base (602) and the slot (5) through the gap in the limiter (10).

[0049] In an embodiment of the invention, the eyebolt mounting mechanism (1 ) comprises aAt least one mounting region (201 ), which is the part between the flange (603) and the reinforcement piece (4) mounted on the inner surface of the shell (2) and surrounding the opening (3) on the shell (2). The mounting region (201 ) is located between the flange (603) and the reinforcement piece (4), allowing sealing.

[0050] In an embodiment of the invention, the eyebolt mounting mechanism (1 ) comprises a bearing element (6) with a bevelled edge compatible with the edges of the opening (3) for mounting on the mounting region (201 ). In this way, the bearing element (6) can be placed to ensure sealing without the need for any work on the edges of the opening (3).

[0051] In an embodiment of the invention, the eyebolt mounting mechanism (1 ) comprises the bearing element (6) whose intersection area of the flange (603) and the lateral wall (601 ) is bevelled to be compatible with the outer surface of the eyebolt (7) for attaching the eyebolt (7) to the teeth on the lateral wall (601 ). The edges of the opening (3) and the perimeter of the eyebolt (7) may have different geometries. Even if the place where the bearing element (6) contacts the periphery of the opening (3) and the place where the eyebolt (7) contacts the bearing element (6) have different geometries, the areas where the lateral wall (601 ) and flange (603) of the bearing element (6) intersect are bevelled internally according to the eyebolt (7) and externally according to the opening (3). In this way, there is no need to carry out any work for mounting on the opening (3) and the eyebolt (7).

[0052] In an embodiment of the invention, the eyebolt mounting mechanism (1 ) comprises screws (8) and nuts (9) that prevent the leakage of fuel by ensuring that the flanges (603), reinforcement piece (4) and mounting region (201 ) to be mounted together. The bearing element (6) is mounted from its flanges (603) to the outer surface of the mounting region (201 ) with screws (8) and nuts (9). In this way, when the eyebolt (7) design is changed or the bearing element (6) becomes worn or damaged, the bearing element (6) can be easily disassembled by removing the screws (8) from the nuts (9).

[0053] In an embodiment of the invention, the eyebolt mounting mechanism (1 ) comprises a nut (9) in the form of a floating type dome nut. In this way, the screw (8) can be mounted on the nut (9) without the need for precise alignment with respect to the screw (8) and drilling with precise tolerances. During assembly, the spring-loaded inner part of the nut (9) moves and can be automatically aligned with the screw (8), thus making it easier to mount the bearing element (6) on the shell (2) and slot (5).

[0054] In an embodiment of the invention, the eyebolt mounting mechanism (1 ) comprises a bearing element (6) that is produced from the same material as the eyebolt (7) and thus prevented from wearing out. By means of the eyebolt (7) and the bearing element (6) being produced from the same material, the wear of both elements is delayed while the eyebolt (7) is mounted on the bearing element (6). In this way, maintenance frequency and maintenance costs are reduced.

[0055] In an embodiment of the invention, the eyebolt mounting mechanism (1 ) comprises a flange (603) which is aerodynamically compatible with the shell (2) and thus minimises the friction force. The mounting region (201 ) and the shell (2) are form-compatible with each other, and aerodynamic friction is minimised by means of the flange (603) design compatible with the shell (2).

[0056] In an embodiment of the invention, the eyebolt mounting mechanism (1 ) comprises the eyebolt (7) and the bearing element (6) made of steel. In this way, by fitting from steel material to steel material, the wear of the teeth on the eyebolt (7) and the bearing element (6) is delayed. This reduces the maintenance frequency of the bearing element (6) and reduces labour and material costs.

[0057] In an embodiment of the invention, the eyebolt mounting mechanism (1 ) comprises a bearing element (6) which is mounted on the shell (2) separately for each eyebolt (7) and can be removed independently of each other when worn out. By means of the bearing element (6) independent of each other, even if one of the bearing elements (6) wears out, the other can be used and replaced independently of each other.

[0058] In an embodiment of the invention, the eyebolt mounting mechanism (1 ) comprises the reinforcement piece (4) which has slots (5) for mounting each bearing element (6) separately and which prevents damage to the shell (2) during jettisoning by being located under the pistons in the aircraft. The reinforcement piece (4) is connected to the beams on the right and left with the screw (8) and nut (9) connection. In this way, the strength of the external fuel tank is increased, and the eyebolts (7) can be mounted, and the external fuel tank can be mounted safely to the aircraft with the eyebolts (7). It may be desired to jettison the external fuel tank with the piston. By means of the reinforcement piece (4) located at the points where the pistons support the external fuel tank, the strength of the external fuel tank is increased and physical damage to it is prevented.

[0059] In an embodiment of the invention, the eyebolt mounting mechanism (1 ) comprises at least one channel (11 ) located in the form of a cavity all around on the lateral wall (601 ) to prevent the bevelled part of the eyebolt (7) from hitting when the eyebolt (7) contacts the limiter (10). In order for the eyebolt (7) to be attached to the teeth on the lateral walls (601 ) and to sit on the limiter (10), there is a channel (11 ) in the form of a cavity all around after the teeth on the lateral wall (601 ). The bevelled edge of the eyebolt (7) enters the channel, and the eyebolt (7) fits snugly into the limiter (10) without damaging the lateral wall (601 ). In this way, the eyebolt (7) is prevented from damaging the bearing element (6) when it contacts the limiter (10).

Claims

CLAIMS1. An eyebolt mounting mechanism (1 ) comprising an external fuel tank shell (2), with aerodynamic surface, at least one opening (3) with a gap on the shell (2), at least one reinforcement piece (4) mounted on the inner surface of the shell (2), at least one slot (5), located in the form of a cavity on the reinforcement piece (4) and accessible through the opening (3), at least one lateral wall (601 ) extending along each slot (5) and having a gear track on it, and at least one eyebolt (7), one end of which is compatible with the teeth on the lateral wall(601 ), thus mounted on the lateral wall (601 ), and the other end of which is attached to the aircraft, characterised by comprising a base (602) opposite the eyebolt (7) and forming the base of the lateral wall (601 ), at least one flange (603) that extends from the lateral wall (601 ) to surround the opening (3) and is mounted on the outer surface of the shell (2), thus allowing almost complete fuel sealing, and a bearing element (6) that is removably attached to the slot (5) and the shell (2), and is formed by the lateral wall (601 ), base (602) and flange (603) being one piece.

2. An eyebolt mounting mechanism (1 ) according to Claim 1 , comprising at least one screw (8) and at least one nut (9) that enable mounting the base (602) to the slot (5).

3. An eyebolt mounting mechanism (1 ) according to Claim 2, comprising at least one limiter (10) located in the form of a protrusion on the inner surface of the bearing element (6) and ensuring that there is a distance between the base(602) and the eyebolt (7) greater than the head height of the screw (8).

4. An eyebolt mounting mechanism (1 ) according to Claim 3, comprising the limiter (10) surrounding the intersection of the base (602) and the lateral wall (601 ).

5. An eyebolt mounting mechanism (1 ) according to any of the previous Claims, comprising at least one mounting region (201 ), which is the region between the flange (603) and the reinforcement piece (4) mounted on the inner surface of the shell (2) and surrounding the opening (3) on the shell (2).

6. An eyebolt mounting mechanism (1 ) according to Claim 5, comprising the bearing element (6) with bevelled edges compatible with the edges of the opening (3) for mounting on the mounting region (201 ).

7. An eyebolt mounting mechanism (1 ) according to any of the previous Claims, comprising the bearing element (6) whose intersection area of the flange (603) and the lateral wall (601 ) is bevelled to be compatible with the outer surface of the eyebolt (7) for attaching the eyebolt (7) to the teeth on the lateral wall (601 ).

8. An eyebolt mounting mechanism (1 ) according to Claims 5 to 7, comprising the screw (8) and the nut (9) that prevent fuel leakage by ensuring that the flanges (603), reinforcement piece (4) and mounting region (201 ) are mounted to one another.

9. An eyebolt mounting mechanism (1 ) according to Claims 2 to 8, comprising the floating type dome nut (9).

10. An eyebolt mounting mechanism (1 ) according to any of the previous Claims, comprising the bearing element (6) that is produced from the same material as the eyebolt (7) and is prevented from wearing out.

11. An eyebolt mounting mechanism (1 ) according to any of the previous Claims, comprising the flange (603), which is aerodynamic form compatible with the shell (2) and thus minimises the friction force.

12. An eyebolt mounting mechanism (1 ) according to any of the previous Claims, comprising the eyebolt (7) and the bearing element (6) made of steel.

13. An eyebolt mounting mechanism (1 ) according to any of the previous Claims, comprising the bearing element (6), which is mounted on the shell (2) separately for each eyebolt (7) and can be removed independently of each other when worn out.

14. An eyebolt mounting mechanism (1 ) according to any of the previous Claims, comprising the reinforcement piece (4) which has slots (5) for mounting each bearing element (6) separately and which prevents damage to the shell (2) during jettisoning by being located under the pistons in the aircraft.

15. An eyebolt mounting mechanism (1 ) according to any of the previous Claims, comprising at least one channel (1 1 ) located in the form of a cavity all around on the lateral wall (601 ) to prevent the bevelled part of the eyebolt (7) from hitting when the eyebolt (7) contacts the limiter (10).

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