Automatic locking type fixing hook

Abstract

The invention relates to a fastening hook (2) having a mechanism for locking a connecting shaft (5), said fastening hook (2) being mounted on a tube (4a) and comprising: a cylindrical body (2a) of linear cross-section (S) connected to the tube (4a) and a base (2f) from which a latch (2g) defining an opening (2h) extends; -a locking slider (3) translating along the cylinder (2a); and a compression spring (1a) located between the locking slide (3) and the tube (4a). The base (2f) and the latch (2g) are housed in a cylindrical volume having the same linear cross-section (S) as an extended portion of the cylinder (2a), the cylinder (2a) comprising at least one elongated guide slot (2d). The locking slider (3) is provided with at least one positioning hole (3a) and a blocking pin (3b), and the blocking pin partially blocks the opening (2h) of the lock catch (2g) of the fixing hook (2).

Description

Technical Field

[0001] The present invention relates to a fixing hook, such as provided at the end of a connecting rod, the fixing hook being configured with an automatic locking system. Such a fixing hook is particularly related to a locking component in a window sash opening holding mechanism to ensure that the window sash remains in the open position after being hung.

[0002] Especially in the aviation field, inspection panels and hatches are movable components of the aircraft's external structure, which can provide access to internal structure components when opened for inspection and / or maintenance operations. To perform these operations, these panels and hatches are connected to a connecting rod after being opened, and such connection can keep the panel or hatch in the open state and prevent the panel or hatch from closing accidentally. When the panels and hatches are closed, the hook can also be used to hook the connecting rod on the panel or hatch frame.

[0003] This hook can also be used to lock a closed panel in its frame. Such hooks can be applied to any other field where manually releasable hooks are used, such as the automotive, marine, and construction industries. Background Art

[0004] Generally speaking, a hook is a tool for hanging and / or fixing an object hanging on the hook. A simple hook usually consists of an anchor, which serves as the hook, and a straight hook body. The hook is made of a rigid material that is not easily deformed. A simple hook can only function when the attached object is subjected to a pulling force at the curved part of the hook head.

[0005] A single hook can also be used to lock a movable component in a specified position. For example, there may be a straight hook on a door, the hook body being fixed near the door edge through a ball-and-socket joint, and the length of the hook being sufficient for the hook anchor to protrude from the door. When the door is closed within its frame, the hook anchor can engage with a ring or a connecting pin connected to the door frame. The connection between the hook and the ring fixes the door on the door frame, thus locking the door in the closed position. This locking method is limited by the quality of the connection between the hook and the ring. This is because simply inserting the hook into the ring means that the hook can be removed from the ring just as simply.

[0006] To fix the hook, a locking device needs to be added to the hook to lock the hooked component. Usually, two methods are used to achieve this locking:

[0007] - One is that the hook closes;

[0008] - Or the hook gets stuck.

[0009] The closure of the hook anchor results in a carabiner - type solution where the carabiner opening forms a closed loop with an opening mechanism. However, a carabiner is an independent hook device and is not installed at the end of a connecting rod. Another solution for closing the hook is to add a retractable mechanism to the hook in order to close the hook anchor. This mechanism increases the volume around the hook to accommodate the mechanism, which hinders and weakens the grip. In addition, the installation and activation of this retractable mechanism also do not allow for the quick locking of the hook.

[0010] Another method is to lock the hook to the hooked structure. This type of hook locking typically uses a device installed on the hooked structure that surrounds the hook and secures it. However, the disadvantage of this solution is the use of an additional mechanism, which increases the occupied space and requires installation and implementation steps.

[0011] The hook can also be closed by a rod connected to a plunger that slides along the body of the hook. A spring located between the body of the hook and the plunger holds the plunger and the rod in the hook - closed position. However, this type of assembly usually requires crimping the hook - closing component to the bottom of the body of the hook, so this hook - closing mechanism is not conducive to the assembly and quick maintenance of the hook. Summary of the Invention

[0012] In order to remedy the disadvantages of the above - mentioned prior art, the main object of the present invention is to improve the locking of the hook.

[0013] To achieve the above object, the present invention provides a locking mechanism that is installed at the bottom of the hook anchor and slides along the straight body of the hook. Advantageously, the mechanism can be automatically locked, thus enabling quick locking without manual operation, thereby extending the installation and fixing position of the hook. In addition, the mechanism can be unlocked without the intervention of any special tools.

[0014] More precisely, the present invention relates to a fixed hook for automatically locking a fastening pin, the fixed hook being installed on a tube and comprising:

[0015] - A cylinder with a straight - line cross - section, including two end portions respectively connected to the tube and a base, and an anchor extending from the base, the anchor defining an opening;

[0016] - A locking plunger that translates along the cylinder; and

[0017] - A reset device arranged between the locking plunger and the tube.

[0018] In the fixed hook, the base and the anchor are arranged within a cylindrical volume having the same linear cross-section as an extension of a cylinder. The cylinder has a hole for inserting the tube, a bottom of the hole, and at least one elongated slot for guiding along the cylinder. Further, the locking plunger has at least one positioning hole and a blocking pin that partially blocks the opening of the hook beak.

[0019] Advantageously, the shape of the hook anchor on the extension of the cylinder reduces the size of the fixed hook and allows the plunger to be inserted into the hook beak. Due to the easy operation of the fixed hook, this makes the installation of the locking plunger quick and simple.

[0020] Also advantageously, locking occurs automatically when the connecting pin is attached. In fact, when the hook approaches the connecting pin and hooks it, the connecting pin contacts the blocking pin of the locking plunger, which partially obstructs the opening of the hook anchor, preventing the connecting pin from entering the opening of the head of the fixed hook. The additional pressure of the connecting pin on the blocking pin moves the plunger towards the reset device until there is enough opening for the connecting pin to enter the opening of the head of the fixed hook and relieve the pressure on the blocking pin. Then the reset device returns the plunger to its original position, the blocking pin again partially blocks the opening of the head of the fixed hook and prevents the connecting pin from disengaging from the fixed hook, thus achieving automatic locking. Release is achieved by manually translating the plunger to move the blocking pin and release the opening of the head of the fixed hook.

[0021] According to a preferred embodiment, taken alone or in combination:

[0022] - The reset device is a compression spring located at the bottom of the hole in the cylinder and abuts against the tube;

[0023] - The cylinder has two diametrically opposed elongated slots;

[0024] - The two elongated slots extend respectively to both sides of the bottom of the hole;

[0025] - The locking plunger includes two diametrically opposed positioning holes;

[0026] - A fixing pin is inserted into the two elongated slots and the two positioning holes, and the fixing pin moves in the two elongated slots;

[0027] - The blocking pin includes a guiding inclined surface;

[0028] - The anchor of the fixed hook has an end with a flat surface that aligns the connecting shaft towards the opening of the anchor of the fixed hook;

[0029] - The base of the fixed hook includes a sliding surface for the blocking pin and a stop surface for the blocking pin of the locking plunger, and

[0030] - The anchor of the fixed hook has a rear surface continuous with the cylinder.

[0031] Advantageously, a compression spring is located within a bore of the cylinder to provide protection for the reset device. The protected spring benefits from the bore drilled in the tube for mounting the fixed hook and optimizes the dimensions of the fixed hook.

[0032] Also advantageously, the guiding inclined surface of the blocking pin allows guiding of the connecting shaft during the hooking process. When the connecting shaft approaches the free space left blocked by the opening part of the fixed hook, the connecting shaft contacts the plane at the end of the hook anchor. Orienting the connecting shaft by means of the plane serves a dual function: orienting the connecting shaft towards the opening of the head of the fixed hook and initiating automatic locking by guiding the thrust of the connecting shaft on the blocking pin to the optimal travel direction of the plunger.

[0033] The invention also relates to a method for automatically locking a connecting shaft in the above-mentioned locking fixed hook, the method comprising the following steps:

[0034] - Positioning a compression spring in a bore;

[0035] - Assembling a cylinder with a tube;

[0036] - Inserting a locking plunger around the fixed hook;

[0037] - Positioning the compression spring within the bore;

[0038] - Assembling the cylinder with the tube;

[0039] - Aligning a plurality of positioning holes of the locking plunger with a plurality of elongated slots of the cylinder; and

[0040] - Inserting a fixing pin into the positioning holes and the elongated guide slots.

[0041] The automatic locking of the connecting shaft occurs in a rest position, in which the blocking pin part of the plunger obstructs the opening of the hook anchor, and proceeds as follows:

[0042] - Positioning the connecting shaft near the opening of the anchor of the fixed hook;

[0043] - Releasing the opening of the anchor of the fixed hook by pressing the connecting shaft against the blocking pin and translating the locking plunger to compress the compression spring;

[0044] - Inserting the connecting shaft fully into the anchor of the fixed hook to fix it; and

[0045] -Reset the compression spring, return the locking plunger to the rest position, and automatically lock the connecting shaft in the fixed hook.

[0046] The advantage is that this automatic locking function is achieved quickly, with only one action and without any tools. In addition, the locking device is fixed by a stop pin, which on the one hand locks the connecting shaft in the fixed hook and on the other hand cannot be operated by the connecting shaft in the fixed hook.

[0047] According to a preferred embodiment, the following are used alone or in combination:

[0048] -By moving the fixed hook to the connecting shaft or vice versa, the blockage of the opening of the anchor of the fixed hook can be removed; and

[0049] -During the step of pulling the locking plunger during the unlocking process, the stop pin slides on a sliding surface of a base of the fixed hook.

[0050] After automatic locking, manual unlocking is required, and the specific steps are as follows:

[0051] -Pull the locking plunger to release the opening of the anchor of the fixed hook;

[0052] -Stop the stop pin on the base of the anchor of the fixed hook and hold the locking plunger in a position;

[0053] -Release the connecting shaft of the anchor of the fixed hook; and

[0054] -Release the locking plunger. Description of the Drawings

[0055] Through the following detailed description of the embodiments and with reference to the drawings, other features and advantages of the present invention will be apparent, but are not intended to limit its scope, where the drawings respectively show:

[0056] – Figure 1 An exemplary exploded perspective view of the automatic locking hook of the present invention;

[0057] – Figure 2 is Figure 1 a perspective view of the bracket in;

[0058] – Figure 3 Another perspective view of the bracket;

[0059] – Figure 4 A side view of the same hook mounted on the connecting rod of an aircraft window frame;

[0060] – Figure 5 A cross-sectional view of the hook;

[0061] – Figure 6 is a view of another cross-section of the hook;

[0062] – Figure 7 is a schematic side view of the locked hook; and

[0063] – Figure 8 is a schematic side view of the hook being unlocked. DETAILED DESCRIPTION

[0064] In the drawings, the same reference numerals denote the same components and the corresponding paragraphs of the specification.

[0065] Figure 1 A disassembled perspective schematic view of a locking fixed hook 2 is shown. The fixed hook 2 allows automatic locking and manual release of a connecting shaft 5 of an aircraft engine cowling (not shown) in the example. The fixed hook 2 is mounted on a tube 4a and includes:

[0066] - A cylinder 2a having a straight cross-section S, which is circular in this example. The cylinder 2a has two ends 2b, 2c respectively connected to the tube 4a, and a base 2f. An anchor 2g extends from the base 2f, and the anchor 2g defines an opening 2h;

[0067] - A locking plunger 3 that translates along the cylinder 2a;

[0068] - A compression spring 1a located between the plunger 3 and the tube 4a; and

[0069] - A fixing pin 1b.

[0070] In the fixed hook 2, the base 2f and the anchor 2g are located within a cylindrical volume that has the same circular straight cross-section S as the cylinder 2a. The cylinder 2a has a hole 2e for inserting into the tube 4a (as shown in Figure 5 ), a bottom 2n for drilling (as shown in Figure 6 ), and two elongated guide grooves 2d that are guided along the cylinder 2a and are diametrically opposite. In addition, the locking plunger 3 has two diametrically opposite positioning holes 3a and a blocking pin 3b. The blocking pin 3b partially blocks the opening 2h of the anchor 2g of the fixed hook 2 (see the perspective view of the fixed hook in Figure 2 ). The base 2f of the fixed hook 2 also has a sliding surface 2i for the blocking pin 3b of the locking plunger 3 and a stop surface 2j for the blocking pin 3b.

[0071] In addition, the fixing pin 1b has a head 1c and fins 1d at its end. The fixing pin 1b is inserted into the positioning hole 3a of the plunger 3 and the elongated guide groove 2d through the fins 1d. Since the head 1c is larger than the positioning hole 3a, the head 1c of the fixing pin 1b does not pass through the plunger 3. Then, the fins 1d are folded and rest against the plunger 3 to prevent the fixing pin 1b from being pulled out. Therefore, the fixing pin 1b fixes the fixing hook 2 and the locking mechanism together, as shown in Figure 2 and Figure 3 in the perspective view. Alternatively, any type of pin can be used to fix the plunger, especially by replacing the head with a sphere, setting fins at both ends of the pin, or using mechanical and / or magnetic locking mechanisms.

[0072] Figure 2 and Figure 3 show the assembly of the hook 2 and the locking mechanism in perspective view and two different angles. The assembly of the locking mechanism is carried out in the following steps:

[0073] - Position the compression spring 1a inside the hole;

[0074] - Assemble the cylinder 2a with the tube 4a;

[0075] - Slip the locking slider 3 around the fixing hook 2;

[0076] - Align the positioning hole 3a of the locking slider 3 with the elongated guide groove 2d of the cylinder 2a;

[0077] - Insert the fixing pin 1b into the positioning hole 3a and the elongated guide groove 2d.

[0078] The cylinder 2a can be attached to the tube 4a by screw connection, crimping, interlocking, welding or any other fixing means. In addition, the guide groove 2d of the cylinder 2a is aligned with the positioning hole 3a of the locking plunger 3, so that the blocking pin 3b is located in front of the opening 2h of the hook 2. In this embodiment, the grooves, holes, blocking pins and the holes of the hook are aligned. However, any other alignment combination can also be adopted, so that the grooves are aligned with the holes, and the alignment direction of the blocking pin and the hole of the hook is different from the alignment direction of the grooves and the holes.

[0079] Figure 4 The hook 2 according to the present invention is shown, which is mounted at the end 4b of the telescopic connecting rod 4. The connecting rod 4 is used to keep, for example, an aircraft engine nacelle cover open, and the connecting rod 4 is connected at its other end 4c through a pivot link 4d. The pivot link 4d can retract or extend the connecting rod 4. When the connecting rod 4 extends, the hook 2 can keep the engine nacelle cover open. For example, the engine nacelle cover has a connecting shaft 5 (see Figure 5(cross-sectional view), the connecting shaft 5 is adapted and configured to engage with the hook 2. In the present application embodiment, the fixed hook, the slider, and the tube are all made of a metallic material. Depending on the weight and usage conditions, these components may also be made of plastic and / or composite materials.

[0080] In another application embodiment, the fixed hook is mounted on the doorframe, and a corresponding connecting shaft is mounted on the door so as to engage with the hook. When the door is closed, the connecting shaft engages with the hook, thereby locking and holding the door closed.

[0081] Figure 5 The sectional view of shows in detail the configuration of the locking mechanism in the locked state. At this time, the compression spring 1a is located at the bottom 2n of the hole 2e of the cylinder 2a and abuts against the tube 4a.

[0082] Specifically: The blocking pin 3b has a guiding inclined surface 3c extending from the edge of the plunger 3 towards the opening 2h of the hook 2, and the guiding inclined surface 3c terminates at a thrust plate 3d perpendicular to the traveling direction of the plunger 3. In addition, the anchor 2g of the hook 2 has an end 2k, and the end 2k has a plane 2l that orients the connecting shaft 5 towards the inner side of the opening 2h of the hook 2. In addition, the anchor 2g of the fixed hook 2 has a back surface 2m that is continuously provided with the outer surface of the cylinder 2a.

[0083] Then the connecting shaft 5 is positioned at the end 2k, the anchor 2g, the fixed hook 2, and the thrust plate 3d of the blocking pin 3b. The dimensions of the plunger 3 and in particular the blocking pin 3b are designed such that, in the locked state, the free space between the end 2k of the anchor 2g and the thrust plate 3d of the blocking pin 3b is smaller than the diameter of the connecting shaft 5. Therefore, in this locked state, the connecting shaft 5 can neither enter nor leave the anchor 2g of the fixed hook 2.

[0084] By pulling the connecting shaft 5 in the direction of the hook anchor, the connecting shaft 5 abuts against the plane 2l at the end 2k of the anchor 2g. The orientation of the plane 2l is such that the connecting shaft 5 extends in the traveling direction of the plunger 3, thereby causing its reaction displacement, and the connecting shaft 5 contacts the thrust plate 3d at the end of the guiding inclined surface 3c of the blocking pin 3d. The thrust plate 3d can be oriented to optimize the action of the connecting shaft 5 on the blocking pin 3b and push the plunger 3 to automatically release the opening 2h of the hook 2.

[0085] Figure 6Another cross-section of the locking mechanism is shown, which shows the position of the elongated guide groove 2d relative to the hole 2e in the cylinder 2a of the hook 2. The compression spring 1a bears against the bottom 2n of the hole 2e, and for the convenience of inserting the fixing pin 1b into the cylinder 2a of the hook 2, the fixing pin 1b is inserted into the end of the compression spring 1a. For this purpose, the elongated guide groove 2d extends on both sides of the bottom 2n of the hole 2e, and the size of the insertion area of the fixing pin 1b in the elongated guide groove 2d is equal to the thickness of the fixing pin 1b.

[0086] Maintain the final state of the fixed hook 2 as Figure 7 shown. When the spring holds the plunger in the locked state, the locking mechanism is in the rest position, in which the blocking pin 3b of the plunger 3 partially blocks the opening 2h of the anchor 2g of the fixed hook 2, as shown in the side view of Figure 7 . The automatic locking from the rest position is carried out according to the following steps:

[0087] - Position the connecting shaft 5 near the opening 2h of the anchor 2g of the fixed hook 2;

[0088] - Release the opening 2h of the anchor 2g of the fixed hook 2 by pressing the connecting pin 5 against the blocking pin 3b and translating the locking plunger 3 to compress the compression spring 1a;

[0089] - Insert the connecting shaft 5 completely into the anchor 2g of the fixed hook 2, and

[0090] - The compression spring 1a resets, causing the locking plunger 3 to return to the rest position, and then automatically locks the connecting shaft 5 in the fixed hook 2.

[0091] The translation of the plunger 3 can be achieved by moving the movable fixing pin 1b in the elongated groove 2d.

[0092] Alternatively, the blocking pin 3b can completely block the opening 2h of the anchor 2g of the fixed hook 2.

[0093] The step of clearing the blockage of the opening 2h of the anchor 2g is achieved by moving the fixed hook 2 to the connecting shaft 5 or vice versa. The blocking pin is constructed such that when the blocking pin 3b is located in the anchor 2g of the fixed hook 2, the connecting shaft 5 cannot exert any effect on the blocking pin 3b to move the plunger 3.

[0094] At the end of the locking, the connecting shaft 5 is hooked, and the locking mechanism returns to the rest position. This locking is called automatic locking because the locking occurs automatically when the connecting shaft is pushed into the opening of the fixed hook.

[0095] The manual unlocking is carried out according to the following steps:

[0096] - Pull the locking plunger 3 so that the opening 2h of the anchor 2g of the fixed hook 2 is not blocked;

[0097] - Stop the blocking pin 3b at the bottom 2f of the anchor 2g of the fixed hook 2 and hold the locking plunger 3 in this position;

[0098] - Release the connecting shaft 5 of the anchor 2g of the fixed hook 2;

[0099] - Release the locking plunger 3.

[0100] During unlocking, in the pulling phase of the plunger 3, the blocking pin 3b slides on the sliding surface 2i at the bottom 2f of the hook 2, and the fixing pin 1b moves into the elongated slot 2d. The movement of the locking plunger 3 is restricted by the stop surface 2j of the base 2f of the fixed hook. Alternatively or in combination, the displacement of the locking plunger can also be restricted by the length of the elongated slot 2d, the stop of the fixing pin 1b at the ends of these elongated slots 2d, the compression of the compression spring 1a, or any other limiting device.

[0101] Figure 8 Shows the configuration of the fixed hook 2 at the end of the said steps. As can be seen from the figure, the locking plunger 3 has completely left the opening 2h of the hook 2, so that by moving the hook 2 to the connecting pin 5 or vice versa, the connecting pin 5 can freely withdraw from the opening 2h of the hook 2.

[0102] The present invention is not limited to the embodiments described and shown. Any type of straight cross-section of a cylindrical body can be envisaged, in particular polygonal or "U" - shaped. In addition, any reminder device (such as an elastic sheet, a tension spring, etc.) with or without a shape memory function can be used. The operation of manually releasing the fixed hook can also be carried out by an automatic and / or controlled mechanism.

Claims

1. A fixing hook (2) having a connecting shaft (5) with automatic locking, the fixing hook (2) being mounted on a tube (4a) and comprising: - A cylinder (2a) with a straight cross-section (S), including two end portions (2b, 2c) respectively connected to the tube (4a) and a base (2f), an anchor (2g) extending from the base (2f), the anchor (2g) defining an opening (2h); - A locking plunger (3) which translates along the cylinder (2a); and - A reset device provided between the locking plunger (3) and the tube (4a); Characterized in that: The base (2f) and the anchor (2g) are arranged within a cylindrical volume having the same straight cross-section (S) as an extension part of the cylinder (2a), the cylinder (2a) having a hole (2e) for inserting the tube (4a), a bottom (2n) of the hole (2e), and at least one elongated slot (2d) for guiding along the cylinder (2a), and the locking plunger (3) having at least one positioning hole (3a) and a blocking pin (3b), the blocking pin (3b) partially blocking the opening (2h) of the anchor (2g).

2. The fixed hook (2) according to claim 1, characterized in that: The reset device is a compression spring (1a) provided at the bottom (2n) of the hole (2e) for inserting into the cylinder (2a) and abutting against the tube (4a).

3. The fixed hook (2) according to any one of claims 1 to 2, characterized in that: The cylinder (2a) has two diametrically opposed elongated slots (2d) extending on both sides of the bottom (2n) of the hole (2e).

4. The fixed hook (2) according to any one of claims 1 to 3, characterized in that: The locking plunger (3) includes two diametrically opposed positioning holes (3a).

5. The fixed hook (2) according to claims 3 to 4, characterized in that: A fixing pin (1b) is inserted into the two elongated slots (2d) and the two positioning holes (3a), and the fixing pin (1b) moves in the two elongated slots (2d).

6. The fixed hook (2) according to any one of claims 1 to 5, characterized in that: The blocking pin (3b) includes a guiding inclined surface.

7. The fixed hook (2) according to any one of claims 1 to 6, characterized in that: The anchor (2g) of the fixing hook (2) has an end portion (2k), and the end portion (2k) has a plane (2l), the plane (2l) orienting the connecting shaft (5) towards the opening (2h) of the anchor (2g) of the fixing hook (2).

8. The fixed hook (2) according to any one of claims 1 to 7, characterized in that: The base (2f) of the fixing hook (2) includes a sliding surface (2i) of the blocking pin (3b) and a stop surface (2j) of the blocking pin (3b) of the locking plunger (3).

9. The fixed hook (2) according to any one of claims 1 to 8, characterized in that: The anchor (2g) of the fixing hook (2) has a rear surface (2m) continuous with the cylinder (2a).

10. A method for automatically locking a fastening pin (5) in a locking fixing hook (2) according to any one of claims 5 to 9, characterized in that: The method includes the following steps: - Positioning a compression spring (1a) in a hole (2e); - Connecting a cylinder (2a) to a tube (4a); - Inserting a locking plunger (3) around the fixing hook (2); - Aligning a plurality of positioning holes (3a) of the locking plunger (3) with a plurality of elongated slots (2d) of the cylinder (2a); And - Inserting a fixing pin (1b) into the positioning holes (3a) and the elongated slots (2d); Among them, the automatic locking of the connecting shaft (5) starts from a stationary position, where the blocking pin (3b) of the locking plunger (3) partially blocks the opening (2h) of the anchor (2g) of the fixed hook (2) according to the following steps: - Position the connecting shaft (5) near the opening (2h) of the anchor (2g) of the fixed hook (2); - By pressing the connecting shaft (5) against the blocking pin (3b) and translating and compressing the locking plunger (3) of the compression spring (1a), the opening (2h) of the anchor (2g) of the fixed hook (2) is unblocked; - Completely insert the connecting shaft (5) into the anchor (2g) that fixes the fixed hook (2); and - Reset the compression spring (1a), return the locking plunger (3) to the stationary position, and automatically lock the connecting shaft (5) in the fixed hook (2).

11. The method according to claim 10, wherein: The step of unblocking the opening (2h) of the anchor (2g) of the fixed hook (2) is achieved by moving the fixed hook (2) to the connecting shaft (5) or vice versa.

12. The method according to any one of claims 10 to 11, characterized in that: In the pulling step of manually releasing the locking plunger (3), the blocking pin (3b) slides on a sliding surface (2i) of a base (2f) of the fixed hook (2).

13. The method according to any one of claims 10 to 12, characterized in that: Automatic locking is followed by manual unlocking, and the manual unlocking includes the following steps: - Pull the locking plunger (3) to unblock the opening (2h) of the anchor (2g) of the fixed hook (2); - Stop the blocking pin (3b) on the base (2f) of the anchor (2g) and hold the locking plunger (3) in a position; - Release the connecting shaft (5) of the anchor (2g) of the fixed hook (2); and - Release the locking plunger (3).

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