GB2071286A

GB2071286A - Aircraft load suspension hook release mechanism

Info

Publication number: GB2071286A
Application number: GB8104232A
Authority: GB
Original assignee: Messerschmitt Bolkow Blohm AG
Current assignee: Airbus Defence and Space GmbH
Priority date: 1980-03-05
Filing date: 1981-02-11
Publication date: 1981-09-16
Also published as: GB2071286B; DE3008397C2; DE3008397A1

Abstract

A device for locking and unlocking an aircraft load suspension hook has a suspension hook 10 locked by means of a rotatable pawl 15. The pawl is loaded by spring 22 and when released (anti-clockwise pivoting) has an arm 17 which acts on surface 24 of the top arm 13 of the hook to rotate same to a release position. The arm 17 does not contact the surface 24 of the hook until the pawl has released from abutment 12 of the hook. A piston 19 driven by gas pressure acts on arm 17 to operate the pawl for release. The nose 14 of the hook is contacted by the load to engage the hook therewith and allow the pawl to enter the abutment ledge 12. <IMAGE>

Description

SPECIFICATION Device for locking and unlocking an aircraft external load-suspension means This invention relates to a device for locking and unlocking the suspension means, such as a hook, used for securing external loads on aircraft.

The suspension hook being locked by a rotatable pawl.

A locking system of this kind is disclosed in German Patent specification 1,158,373 wherein the suspension hook is fixed in the load receiving position, i.e. when the load is suspended thereon by means of a pawl bearing on a detent. The pawl is rotatable through a rod system so that to release the external load the suspension hook itself can be turned. The rotatory movement of the suspension hook is effected by separate rod systems.

This invention seeks to provide an apparatus of the kind referred to wherein rotation of the pawl can be used also for rotating the suspension means such as a hook.

According to this invention there is provided a device for locking and unlocking an aircraft external load suspension hook wherein the hook is locked by a rotatable pawl, the-device being arranged so that when the hook is released for pivoting movement the pawl which is normally urged into engagement with the hook by a spring, has an arm which bears against-a surface of the hook to rotate same to the release position, the said arm engaging said surface following release of the pawl from an abutment on the hook.

An advantage is that the device according to the invention as a result of the interdependent actions, is self-locking and accidental operation is not possible. A further advantage is the small number of moving parts resulting in a reduction of weight, space and cost.

The invention is further described and illustrated with reference to the accompanying drawings, wherein Figure 1 shows a load suspension hook with a pawl, and Figure 2 shows a modification with a different means for rotation of the pawl.

Referring to Figure 1, a load suspension means comprises a hook 10 pivotally mounted on a shaft 11 and secured to a load mounting point on an aircraft (not shown).

The hook 10 has an abutment ledge 12, a top arm 13 and a nose 14. To the top arm 13 is pivotally connected a rod 20 supporting a spring 21. The other end the rod 20 is pivoted on the load mounting-point.

A pawl 15 is rotatably mounted on shaft 16 and is subject to force of a spring 22. The pawl 1 5 has an arm 17 positioned adjacent a surface 24 of the top arm 13 of the hook 10. Against the arm 17 of the pawl 1 5 bears a piston 1 8 of an actuating device 19. The actuating device 19 may be activated either pyrotechnically, pneumatically, hydraulically or electro-mechanically.

The locking and unlocking sequence of the hook 10 commences with the attachment of an external load which may have a saddle or a lug. In the load attachment the hook 10, under force of the spring.21 first takes up the extended released position where the external load exerts force on the nose 14. The hook is thus caused to pivot clockwise and engages the-external load.

The pawl 15, which was pivoted to the right and which rested against stop 23, can now rotate clockwise under the force-of spring,22 and bears on the abutment 12 of the hook 10. The hook 10 is thus locked and accidental release of the external load is not possible. The hook in this position is also biasedby spring 21.

If-the external load is to be released the actuating device 19 is operated, for example, by a pyrotechnic generated pressure gas, whereby the piston 18 is moved to the left. The arm 17 is thereby rotated-to contact the surface 24 with the distance arranged to ensure that the abutment 12 is released. Under the effect of the piston 1 8 the pawl 1 5 is further turned so that the hook 10 is also rotated, this being assisted by the spring 21.

The hook 10 releases the external load after a certain rotational movement. And spring 22 is again biased. Due to the spring 21 the hook 10 remains in the released position.

The rod 25 serves for manual release on the ground or for an emergency release operation.

Figure 2 shows a modification wherein the rotation of the pawl 30 is effected by means of pinion 31 and rack 32. The rack 32 forms part of the actuating device 33, which can be operated as previously described. The method af operation is otherwise the same as of the device shown in Figure 1.

The pawl 1 5 can be rotated by rotating the shaft 16, for example, by means of an electric motor or the like, and a keyed spring can be used, as is known, to cause the pawl 15 to accompany the rotation.

1. Device for locking and unlocking an aircraft external load suspension hook wherein the hook is locked by a rotatable pawl, the device being arranged so that when the hook is released for pivoting movement the pawl which is normally urged into engagement with the hook by a spring, has an arm which bears against a surface of the hook to rotate same to the release position, the said arm enyaging said surface following release of the pawl from.an abutment on the hook.

2. Device-in accordance with Claim 1, wherein the pawl is rotatable about a pivot through a piston which can be actuated by gas or fluid pressure.

3. Device in accordance with Claim 1, wherein the pawl has a pinion rotatable about a pivot by a rack which can be operated by gas or.fluid pressure.

4. Device in accordance with Claim 1, wherein the pawl is rotatable about a shaft.

5. Device in accordance with any one of Claims 2, 3 or 4, wherein the release direction of pivoting

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Device for locking and unlocking an aircraft external load-suspension means This invention relates to a device for locking and unlocking the suspension means, such as a hook, used for securing external loads on aircraft. The suspension hook being locked by a rotatable pawl. A locking system of this kind is disclosed in German Patent specification 1,158,373 wherein the suspension hook is fixed in the load receiving position, i.e. when the load is suspended thereon by means of a pawl bearing on a detent. The pawl is rotatable through a rod system so that to release the external load the suspension hook itself can be turned. The rotatory movement of the suspension hook is effected by separate rod systems. This invention seeks to provide an apparatus of the kind referred to wherein rotation of the pawl can be used also for rotating the suspension means such as a hook. According to this invention there is provided a device for locking and unlocking an aircraft external load suspension hook wherein the hook is locked by a rotatable pawl, the-device being arranged so that when the hook is released for pivoting movement the pawl which is normally urged into engagement with the hook by a spring, has an arm which bears against-a surface of the hook to rotate same to the release position, the said arm engaging said surface following release of the pawl from an abutment on the hook. An advantage is that the device according to the invention as a result of the interdependent actions, is self-locking and accidental operation is not possible. A further advantage is the small number of moving parts resulting in a reduction of weight, space and cost. The invention is further described and illustrated with reference to the accompanying drawings, wherein Figure 1 shows a load suspension hook with a pawl, and Figure 2 shows a modification with a different means for rotation of the pawl. Referring to Figure 1, a load suspension means comprises a hook 10 pivotally mounted on a shaft 11 and secured to a load mounting point on an aircraft (not shown). The hook 10 has an abutment ledge 12, a top arm 13 and a nose 14. To the top arm 13 is pivotally connected a rod 20 supporting a spring 21. The other end the rod 20 is pivoted on the load mounting-point. A pawl 15 is rotatably mounted on shaft 16 and is subject to force of a spring 22. The pawl 1 5 has an arm 17 positioned adjacent a surface 24 of the top arm 13 of the hook 10. Against the arm 17 of the pawl 1 5 bears a piston 1 8 of an actuating device 19. The actuating device 19 may be activated either pyrotechnically, pneumatically, hydraulically or electro-mechanically. The locking and unlocking sequence of the hook 10 commences with the attachment of an external load which may have a saddle or a lug. In the load attachment the hook 10, under force of the spring.21 first takes up the extended released position where the external load exerts force on the nose 14. The hook is thus caused to pivot clockwise and engages the-external load. The pawl 15, which was pivoted to the right and which rested against stop 23, can now rotate clockwise under the force-of spring,22 and bears on the abutment 12 of the hook 10. The hook 10 is thus locked and accidental release of the external load is not possible. The hook in this position is also biasedby spring 21. If-the external load is to be released the actuating device 19 is operated, for example, by a pyrotechnic generated pressure gas, whereby the piston 18 is moved to the left. The arm 17 is thereby rotated-to contact the surface 24 with the distance arranged to ensure that the abutment 12 is released. Under the effect of the piston 1 8 the pawl 1 5 is further turned so that the hook 10 is also rotated, this being assisted by the spring 21. The hook 10 releases the external load after a certain rotational movement. And spring 22 is again biased. Due to the spring 21 the hook 10 remains in the released position. The rod 25 serves for manual release on the ground or for an emergency release operation. Figure 2 shows a modification wherein the rotation of the pawl 30 is effected by means of pinion 31 and rack 32. The rack 32 forms part of the actuating device 33, which can be operated as previously described. The method af operation is otherwise the same as of the device shown in Figure 1. The pawl 1 5 can be rotated by rotating the shaft 16, for example, by means of an electric motor or the like, and a keyed spring can be used, as is known, to cause the pawl 15 to accompany the rotation. CLAIMS

5. Device in accordance with any one of Claims 2, 3 or 4, wherein the release direction of pivoting of the hook is assisted by a spring acting on a top arm with the spring being prestressed when an external load engages the hook the external load causing the hook to rotate by contact with a nose on the hook.

6. Device in accordance with any preceding claim, wherein the pawl has an associated rod pivotally connected therewith and serving to release same from the hook.

7. A load securing hook for an aircraft constructed and arranged to function substantially as herein described with reference to and as shown in Figure 1 or Figure 2 of the accompanying drawings.