GB2513646A

GB2513646A - Cargo hook

Info

Publication number: GB2513646A
Application number: GB201307991A
Authority: GB
Inventors: Kieran Leigh Dray
Original assignee: DRALLIM Ltd
Current assignee: DRALLIM Ltd
Priority date: 2013-05-02
Filing date: 2013-05-02
Publication date: 2014-11-05
Anticipated expiration: 2033-05-02
Also published as: GB201307991D0; GB2513646B

Abstract

A cargo hook 10 suitable for carrying a load comprising a housing 20, a load beam 30 which is mounted to the housing and is moveable relative to the housing 20 between a closed position and an open position, a latch mechanism 40 with a locked condition that locks the load beam 30 in the closed position and an unlocked condition that allows the load beam 30 to move from the closed to open position and a moveable stop 70 which engages with the latch mechanism 40 and has a first position that prevents the movement of the latch mechanism 40 from the locked condition and a second condition which permits movement from the locked condition to the unlocked condition. The moveable stop 70 effectively provides a safety lock for the latch mechanism 40. The moveable stop 70 automatically adopts the first position when a load greater than or equal to a specified value is carried by the load beam 30 and adopts the second position when no load or a load less than a specified value is carried. The moveable stop 70 may also be deployed manually. This device is suitable for use with loads underslung beneath a helicopter.

Description

Cargo Hook The present invention relates to a cargo hook, such as a cargo hook for use with a helicopter.

Cargo hooks are widely used to lift and move cargo loads. They may be used on a crane, and whilst the present invention may be used to provide a cargo hook for a conventional crane (static or mobile), the particular advantages of the present invention relate to its use with loads underslung beneath a helicopter (or other vertical take-off aircraft).

A typical arrangement for carrying a load beneath a helicopter employs two hooks, a primary and a secondary. The primary hook is connected directly to one or more structural mounting points of the helicopter and the secondary hook is suspended from the primary hook on a strop.

The aerodynamics of a helicopter make it very sensitive to its loading and there is a variety of conditions which could put the safety of the helicopter and its crew at risk due to the presence of an underslung load. The helicopter may be flying in a dangerous environment as a result of the terrain, weather conditions, or military action. Alternatively, the helicopter may experience technical difficulties during take-oft flight or landing. Finally, the load may simply be found to be excessive during take-off. In each of these situations, it can be useful or even essential to be able to release the load quickly and allow it to fall to the ground. This is generally known as emergency jettison mode.

Cargo hooks typically have a load beam which is able to move or pivot between a closed, load-bearing position and an open position in which the load (or more usually the strops carrying the load) can be released from the hook. The hook will be provided with a latch which latches the load beam (and therefore the cargo hook) in the closed position during flight. In order to be able to release the load quickly, one or more electrical release mechanisms may be provided which can be operated from inside the helicopter by the crew to release the latch and allow the load beam to adopt the open position. As a back-up, one or more manual release mechanisms may also be provided, which could be provided in the form of an operating lever on the cargo hook itself and/or in the form of a manual cable release or hydraulic system which may also be operated from inside the helicopter.

One of the problems with such an arrangement is the risk of accidental release of the load through unintentional operation of the electrical/mechanical release mechanism by the crew or through a mechanical or electrical fault. If loading/unloading operations are in progress or if the aircraft is in flight, this will clearly be dangerous.

Whilst systems and operational procedures have been developed at the operator's end of such mechanisms to prevent inadvertent release, it would be desirable, while allowing the load beam to be released during normal cargo handling operations, to provide an additional safeguard against inadvertent release of the load within the cargo hook itself.

It will be understood that similar problems may occur with cargo hooks for use with a conventional crane. The present invention seeks to provide a cargo hook which overcomes these issues.

The present invention provides a cargo hook for carrying a load, comprising a housing, a load beam mounted to the housing and movable relative to the housing between a closed position for carrying a load and an open position for releasing the load, a latch mechanism having a locked condition which locks the load beam in the closed position and an unlocked condition which allows the load beam to move from the closed to the open position, and a movable stop which selectively engages with the latch mechanism and has a first position which prevents movement of the latch mechanism from the locked condition and a second position which permits movement of the latch mechanism from the locked condition to the unlocked condition.

While it is possible that the movable stop and its means of operation may include one or more electrical or electronic components, such as a solenoid for example, preferably the mechanism is entirely mechanical in order that it is immune to electrical failures or accidental triggering.

In particularly preferred embodiments, the operation of the movable stop is automatic. Its operation may be automatically triggered for example when a load is carried by the load beam. Preferably, therefore, the movable stop automatically adopts the first position when the latch mechanism is in the locked condition and a load or a load greater than or equal to a predetermined value is carried by the load beam. Conversely, the movable stop preferably automatically adopts the second position when no load or a load less than a predetermined value is carried by the load beam.

The predetermined load value may be about 100 Kg or less or about 50Kg or less.

For example, if the predetermined load value is set at about 50Kg such that the movable stop allows the latch mechanism to operate normally if a load of less than Kg is carried by the hook, this will allow for the typical weight of an empty cargo net to be carried and to be released (by remote operation of the latch mechanism) while being carried, such as during flight. If a load of greater than 50 Kg is being carried, the movable stop prevents the latch mechanism from being released remotely and therefore jettison mode is disabled.

A jettison function may still be provided, such as by means of releasing the primary hook and therefore the entire long line and secondary cargo hook combination, the latter employing the invention. Alternatively, a secondary jettison release system may be provided, which could be provided on the same hook as the invention but via a separate control system (e.g. solenoid or cable release). Because neither of these jettison functions would be used during normal cargo handling operations, the risk of inadvertent operation is significantly reduced. The present invention is of course equally applicable to primary or secondary cargo hooks.

In preferred embodiments, the movable stop is in effect an additional safety lock for the latch mechanism. Its operation is preferably uni-directional and does not prevent movement of the latch from the unlocked condition to the locked condition. The movable stop is preferably resiliently biased towards the first position, by means of a

spring for example.

The housing preferably includes an upper suspension point from which the cargo hook is suspended in use, such as from a strop slung underneath a helicopter or from a crane. The load beam is preferably rotatably mounted to the housing at a pivot point, about which the load beam rotates between the closed and open positions.

A preferred automatic operation of the movable stop is achieved by an arrangement in which limited relative movement is possible between the load beam and the upper suspension point. When a load is applied to the load beam, the load beam and suspension point move apart to a limited degree, possibly against a resilient biasing force provided by a spring for example, and this movement can be used to transfer movement to the movable stop. In effect, the relative position of the load beam and suspension point determines the position of the movable stop.

Preferably therefore, the cargo hook is configured to allow limited movement of the load beam relative to the upper suspension point against a resilient biasing force, such that, when the hook is suspended from the upper suspension point and no load is applied to the load beam, the movable stop adopts the second position and, when a load is applied to the load beam sufficient to overcome the resilient biasing force to move the load beam relative to the upper suspension point, the movable stop moves to the first position. In a preferred arrangement, the movable stop is biased towards the first position and, when no load is applied to the load beam, a force is applied to the movable stop against the movable stop biasing force to cause the movable stop to adopt the second position. As discussed above, this force may be applied to the movable stop by virtue of the load beam and suspension point being at their relative closest. When a load is applied to the load beam sufficient to overcome the resilient biasing force to move the load beam relative to the upper suspension point, the force on the movable stop is preferably removed or reduced such that the movable stop adopts the first position under the movable stop biasing force.

In a preferred arrangement, the housing comprises upper and lower housing sections, the upper suspension point being provided on the upper housing section and the load beam being mounted to the lower housing section. The upper and lower housing sections may be capable of limited relative movement under a resilient biasing force, which movement provides the limited movement of the load beam relative to the upper suspension point. In a particularly preferred embodiment, it is the upper housing section which provides the force on the movable stop to cause it to adopt the second position.

The latch mechanism preferably comprises a latch and a latch lock. The latch is preferably movable between a closed position and an open position, such that, when the latch mechanism is in the locked condition, the latch is locked in the closed position and engages with the load beam to lock the load beam in the closed position. When the latch mechanism is in the unlocked condition, the latch is free to move from the closed position to the open position. In a preferred arrangement, the unlocked latch does not automatically move to the open position, but it can be moved to that position by the load beam as the load beam moves from the closed position to the open position.

The latch may comprise a latch arm rotatably mounted to the housing at a pivot point intermediate each end of the latch arm to divide the arm into two arm sections. One arm section engages with the load beam when the latch is in the closed position.

The latch lock selectively engages with the latch and has a locked position which prevents movement of the latch from the closed position and an unlocked position which permits movement of the latch from the closed position to the open position.

In the embodiment where the latch comprises two arm sections, one of which engages with the load beam when the latch is in the closed position, the latch lock engages with the other arm section when in the locked position.

The latch lock is preferably rotatably mounted to the housing at a pivot point, and may comprise a first rotatable arm which engages with the latch in the locked position to prevent movement of the latch from the closed position and which rotates to the unlocked position to permit movement of the latch from the closed position to the open position. A second rotatable arm rotatably fixed in relation to the first rotatable arm may be provided as part of the latch lock, with which the movable stop selectively engages to prevent rotation of the first rotatable arm from the locked position to the unlocked position.

The movable stop preferably comprises an arm which selectively engages with the latch mechanism, the latch lock or the second rotatable arm of the latch lock to prevent movement of the latch mechanism from the locked condition, or the latch lock from the locked position as appropriate. The movable stop arm may be rotatably mounted to the housing at a pivot point, about which the arm rotates between the first and second positions.

In order to move the latch mechanism from the locked condition to the unlocked condition when the movable stop is in the second position, actuating means are preferably provided. The actuating means may be connected to the latch lock and configured to rotate the latch lock between the locked position and the unlocked position, under the resilient biasing force of a spring for example. The actuating means may be mechanical, such as a manual operating lever, or may include an electrically-operated component, such as a solenoid, so that the latch mechanism may be remotely unlocked.

Status monitoring means may also be added, comprising for example a microswitch or other sensor. Monitoring means may be provided for the actuating means referred to above, and/or for the load beam position, or in some other form to provide a "load on" indication. Indication may be provided on the hook itself (in the form of an external light or other visual signal, or in the form of an audible signal) and/or remotely, such as within the helicopter or crane.

Means for over-riding the movable stop and preventing it from adopting the first position or holding it in the second position may be provided. Such means may be mechanically-or electrically-operated, either locally on the hook or remotely.

Means for monitoring the status of the cargo hook may be provided, the status information being provided to the helicopter crew, crane operator or ground personnel as appropriate.

The parts of the cargo hook are made of materials appropriate to its use, and the housing is preferably made of a lightweight material such as aluminium or duralumin and the load beam, latch, latch lock and movable stop are preferably of stainless steel.

A preferred embodiment of the invention will now be described by way of example and with reference to the accompanying drawings in which: Fig. 1 shows a front perspective view of a cargo hook in accordance with the invention; Fig. 2 shows a rear perspective view of the cargo hook of Fig. 1; Fig. 3 shows a front elevation of the cargo hook with the front cover removed to show the internal components, in which the load beam is closed, the latch mechanism is locked and the movable stop is in the first, blocking position; Fig. 4 shows a similar view to Fig. 3, in which the load beam is closed, the latch mechanism is locked and the movable stop is in the second, releasing position; Fig. S shows a rear elevation of the cargo hook with the rear cover removed to show the internal components which are in the same position as in Fig. 4; Fig. 6 shows a similar view to Figs. 3 and 4, in which the latch mechanism is unlocked and the load beam is open; Fig. JA shows a detailed perspective view of the cargo hook showing the movable stop in the first position; Fig. 7B shows the same view as Fig. 7A, with the movable stop in the second position; Fig. BA shows a partial sectional view of the cargo hook showing the movable stop in the first position; and Fig. 8B shows the same view as Fig. BA, with the movable stop in the second position.

With reference to Figs. 1 and 2, cargo hook 10 comprises a housing shown generally as 20 and comprising upper housing section 21 and lower housing section 22. Upper housing section 21 is able to move relative to lower housing section 22 to a limited extent, as will be described below. Upper suspension point 23 is provided on upper housing section 21. The housing also includes an electrical socket 24 (Fig. 1) on the front side for connection to one or more actuating components within the hook such as a solenoid (mounted within solenoid housing 25) and/or to status monitoring components such as position switches and the like. A cover flap 26 (Fig. 2) is provided on the rear side which provides access to a manual actuating lever as described below with reference to Fig. S. A load beam 30 is pivotally mounted to lower housing section 22.

Figs. 3-6 show the internal components of cargo hook 10. Load beam 30 can be seen to be the lower arm of an overall load beam member 31, which is generally U-shaped and comprises a lower arm being the load beam 30 and upper arm 32 which engages the latch mechanism, discussed further below. Load beam member 31 pivots about pivot point 33 and is able to rotate between a closed position (Figs. 3-5) and an open position (Fig. 6). A spring 34 acts on the load beam member at a point offset slightly from the pivot axis to urge the load beam member 31 towards the open position, which it will automatically adopt when the latch mechanism is released. Spring 34 is an optional feature and the mechanism works the same way with or without it.

With reference to the same figures, the general latch mechanism operation will now be described. The latch mechanism is shown generally as 40 and comprises two main components, latch 50 and latch lock 60. Latch 50 is rotatably mounted to the housing at a pivot point 51, about which the latch rotates between a closed position (Figs. 3- 5) and an open position (Fig. 6). The position of pivot point 51 divides latch 50 into two arms, which in this preferred embodiment are disposed at an angle of about 130 degrees relative to one another.

First latch arm 52 engages with the end of load beam member upper arm 32 when the latch is in the closed position, as shown in Figs. 3-5. First latch arm 52 comprises two spaced parallel plates 53, only one of which is visible in the drawings, separated by a roller 54, the end of which is visible in the drawings. When the latch 50 is locked in the closed position, the end of upper arm 32 of the load beam member 31 projects between the two parallel plates 53 and the load beam member 31 is held in the closed position by roller 54. Second latch arm 55, which is fixed to and rotates with first latch arm 52, extends from pivot point 51 and ends at a roller 56.

Latch lock 60 selectively engages with the latch 50 and has a locked position which prevents movement of the latch 50 from the closed position and an unlocked position which permits movement of the latch 50 from the closed position to the open position. Latch lock 60 comprises a central hub 61 about which first arm 62 rotates between a locked position (Figs. 3-5) and an unlocked position (Fig. 6). The latch lock 60 is biased in a clockwise direction (as viewed in Figs. 3, 4 & 6) towards the locked position by means of spring 63 which attaches to the latch lock GOat projection 64.

Latch lock 60 also includes a roller 65 which rotates with first arm 62 and which is mounted on a second latch lock arm 66. Roller 65 contacts the upper surface 35 of load beam member 31, the upper surface being profiled with a step 36 such that when the load beam member is in the open position, roller 65 and therefore latch lock 60 is held in the unlocked position (Fig. 6). Roller 65 also provides a secondary latch for load beam member 31 against step 36, should the main latch 50 fail for any reason.

When the latch lock 60 is in the locked position, the end of first arm 62 engages latch roller 56 and prevents latch 50 from rotating to the open position. In order to unlock the latch, latch lock 60 is rotated to the unlocked position (Fig. 6), which allows latch roller 56 to fall and latch 50 to rotate about its pivot point 51 to the open position.

Latch 50 does not automatically move to the open position, although a spring can be added to achieve this, but in either case the end of load beam upper arm 32 pushes the latch to the open position through contact with roller 54, under the biasing force provided by spring 34. Latch lock 60 is then held in the unlocked position by means of upper surface 35 of the load beam member acting on roller 65, as described above.

In reverse, the locking of the load beam member in the closed position is automatic.

The load beam member 31 is typically closed by hand by the loading crew. It is possible to close the load beam member 31 with one hand by pushing the load attachment means (usually a strop shackle) against load beam upper arm 32, this operation being easier if the load beam is not sprung towards the open position. As the load beam member rotates about pivot point 33 to the closed position, roller 65 passes step 36 which allows latch lock 60 to tend to rotate to the locked position under the biasing force of spring 63. Once the end of load beam upper arm 32 has moved in an upwards direction past latch roller 54, latch 50 is moved to the closed position by means of the edge profile 67 of latch lock first arm 62, which is designed to push roller 56 upwards and therefore rotate the latch 50 to the closed position.

In the unlocking procedure, latch lock 60 is rotated from the locked to the unlocked position either by electrical means such as a solenoid, located within solenoid housing 25, acting on latch lock central hub 61, or by manual means such as manual lever 68 (Fig. 5) which is accessible by lifting cover flap 26 (Fig. 2).

The main aspect of the invention relates to the movable stop 70. As mentioned above, movable stop 70 provides a safety lock for the latch mechanism 40. It does this by selectively blocking or releasing roller 65 of latch lock 60. Fig. 3 shows movable stop 70 in the first, blocking position in which roller 65 is prevented from moving, thereby preventing latch lock 60 from rotating out of the locked position.

Figs. 4-6 show the movable stop in the second, releasing position, which allows the latch lock 60 to function normally, as described above.

Figs. 7A and 7B show movable stop 70 in more detail. Movable stop 70is in the form of an angled plate which pivots about pivot point 71. The movable stop comprises a first arm 72 which selectively blocks or releases the latch lock roller 65 and a second arm 73 to the end of which is attached a spring 74 for biasing the first arm towards the first, blocking position. It can be seen from Fig. 7A that the end surface 75 of first arm 72 effectively blocks roller 65 from moving upwards when the movable stop is in the first position.

Fig. 7B shows the movable stop 70 in the second, releasing position. In order to adopt this position, a force to counter the biasing force of spring 74 needs to be provided so that movable stop 70 rotates about pivot point 71 in a clockwise direction. This force is provided by projection 80 which acts on a shoulder 76 of the movable stop 70. Projection 80 is connected to upper housing 21, and provides the force on movable stop 70 in the manner described below.

With reference to Figs. 3 and 7A, the right-hand end of upper housing section 21 is able to move relative to lower housing section 22 to a limited extent, against the biasing force of springs 27. The lower ends of springs 27 are attached to lower housing section 22 and the upper ends of springs 27 are attached to upper housing section 21, and more specifically to bolt 28.

With reference to Figs. 8A and SB, while bolt 27 is fixed in relation to upper housing section 21, it is able to move within an oval hole or channel 29 within lower housing section 22. Projection 80 is attached to upper housing section 21 and will therefore move relative to lower housing section 22 (and relative to movable stop pivot point 71) when sufficient load is applied to the load beam 30 to overcome the biasing force of springs 27.

Fig. BA shows the arrangement with a load applied to the load beam 30 sufficient to counter the biasing force of springs 27, such that bolt 28 is at the top of the oval channel 29 and projection 80 is therefore also in its uppermost position, allowing movable stop 70 to adopt the first, blocking position under biasing force of spring 74.

Fig. SB shows the arrangement with no load applied to the load beam 30, or a load which is insufficient to counter the biasing force of springs 27 (e.g. an empty cargo net), such that bolt 28 is at the bottom of oval channel 29 and projection 80 is therefore also in its lowermost position. In this position, projection 80 provides a force on shoulder 76 to counter the biasing force of spring 74 and urge movable stop to the second, releasing position.

In summary, the arrangement provides automatic deployment of movable stop 70 when a load of a certain value or above is carried by load beam 30. It can also be seen that the blocking function of the movable stop 70 is uni-directional and only works to prevent movement of latch lock roller 65 from the locked position to the unlocked position. It does not prevent movement in the reverse direction, from the unlocked position to the locked position.

Claims

Claims 1. A cargo hook for carrying a load, comprising a housing; a load beam mounted to the housing and movable relative to the housing between a closed position for carrying a load and an open position for releasing the load; a latch mechanism having a locked condition which locks the load beam in the closed position and an unlocked condition which allows the load beam to move from the closed to the open position; and a movable stop which selectively engages with the latch mechanism and has a first position which prevents movement of the latch mechanism from the locked condition and a second position which permits movement of the latch mechanism from the locked condition to the unlocked condition.
2. The cargo hook of claim 1, in which the movable stop automatically adopts the first position when the latch mechanism is in the locked condition and a load or a load greater than or equal to a predetermined value is carried by the load beam.
3. The cargo hook of claim 1 or 2, in which the movable stop automatically adopts the second position when no load or a load less than a predetermined value is carried by the load beam.
4. The cargo hook of any preceding claim, in which the movable stop is resiliently biased towards the first position.
5. The cargo hook of any preceding claim, in which the movable stop operation is uni-directional and does not prevent movement of the latch from the unlocked condition to the locked condition.
6. The cargo hook of any preceding claim, in which the housing includes an upper suspension point from which the cargo hook is suspended in use.
7. The cargo hook of claim 6, in which the hook is configured to allow limited movement of the load beam relative to the upper suspension point against a resilient biasing force, such that, when the hook is suspended from the upper suspension point and no load is applied to the load beam, the movable stop adopts the second position and, when a load is applied to the load beam sufficient to overcome the resilient biasing force to move the load beam relative to the upper suspension point, the movable stop moves to the first position.
8. The cargo hook of claim 7, in which the movable stop is biased towards the first position and in which, when no load is applied to the load beam, a force is applied to the movable stop against the movable stop biasing force to cause the movable stop to adopt the second position.
9. The cargo hook of claims, in which, when a load is applied to the load beam sufficient to overcome the resilient biasing force to move the load beam relative to the upper suspension point, the force on the movable stop is removed or reduced such that the movable stop adopts the first position under the movable stop biasing force.
10. The cargo hook of any of claims] to9, in which the housing comprises upper and lower housing sections, the upper suspension point being provided on the upper housing section and the load beam being mounted to the lower housing section, wherein the upper and lower housing sections are capable of limited relative movement under a resilient biasing force, which movement provides the limited movement of the load beam relative to the upper suspension point.
11. The cargo hook of claim 10 and claim 8 or claim 9, in which the upper housing section provides the force on the movable stop to cause it to adopt the second position.
12. The cargo hook of any preceding claim, in which the load beam is rotatably mounted to the housing at a pivot point, about which the load beam rotates between the closed and open positions.
13. The cargo hook of any preceding claim, in which the latch mechanism comprises a latch movable between a closed position and an open position, such that, when the latch mechanism is in the locked condition, the latch is locked in the closed position and engages with the load beam to lock the load beam in the closed position.
14. The cargo hook of claim 13, in which the latch is free to move from the closed position to the open position when the latch mechanism is in the unlocked condition.
15. The cargo hook of claim 14, in which the load beam moves the unlocked latch from the closed position to the open position as the load beam moves from the closed position to the open position.
16. The cargo hook of any of claims 13 to 15, in which the latch comprises a latch arm rotatably mounted to the housing at a pivot point intermediate each end of the latch arm to divide the arm into two arm sections, wherein one arm section engages with the load beam when the latch is in the closed position.
17. The cargo hook of any of claims 13 to 16, in which the latch mechanism further comprises a latch lock which selectively engages with the latch and has a locked position which prevents movement of the latch from the closed position and an unlocked position which permits movement of the latch from the closed position to the open position.
18. The cargo hook of claim 16 and 17, in which the latch lock engages with the other arm section of the latch arm in the locked position.
19. The cargo hook of claim 17 or 18, in which the latch lock is rotatably mounted to the housing at a pivot point.
20. The cargo hook of claim 19, in which the latch lock comprises a first rotatable arm which engages with the latch in the locked position to prevent movement of the latch from the closed position and which rotates to the unlocked position to permit movement of the latch from the closed position to the open position.
21. The cargo hook of any preceding claim, in which the movable stop comprises an arm which selectively engages with the latch mechanism and which is rotatably mounted to the housing at a pivot point, about which the arm rotates between the first and second positions.
22. The cargo hook of claim 21 and any of claims 17 to 20, in which the movable stop arm selectively engages with the latch lock and prevents movement of the latch lock from the locked position to the unlocked position.
23. The cargo hook of claims 20 and 21, in which the latch lock includes a second rotatable arm which is rotatably fixed in relation to the first rotatable arm, the movable stop arm selectively engaging with the second rotatable arm to prevent rotation of the first rotatable arm from the locked position to the unlocked position.
24. The cargo hook of any preceding claim, further comprising actuating means for moving the latch mechanism from the locked condition to the unlocked condition when the movable stop is in the second position.
25. The cargo hook of claim 24, in which the actuating means comprises a manual operating lever.
26. The cargo hook of claim 24, in which the actuating means comprises an electrically-operated actuating means such as a solenoid.
27. The cargo hook of any of claims 24 to 26 when dependent on claim 18, in which the actuating means rotates the latch lock from the locked position to the unlocked position.
28. A cargo hook substantially as described herein with reference to the accompanying drawings.