GB2259083A - Locking hook assembly for cargo handling system - Google Patents

Abstract

A cargo handling system 10 includes an L-shaped lifting arm 12 provided with a fixed lifting hook 14 and pivotable horizontally during a loading cycle between a loading position A and a loaded position C/D. The lifting hook 14 has two locking plates 28 pivoted one to either side of the hook 14 and these are driven to close the mouth of the hook by a forward surface 38 of the container or loading platform during the latter part of the loading cycle. Springs 35 bias the locking plates towards their inoperative (ie open) position. <IMAGE>

Description

"Locking Hook Assembly for Carao Handlinq System" This invention relates to a locking hook assembly for a cargo handling system and, in particular, but not exclusively to a locking hook assembly for a lifting arm for a container lifting system for transferring containers or other load platforms on or off a vehicle.

In typical such systems, an L-shaped lifting arm carries at its upper end a hook and is pivotable relative to the vehicle chassis to reach over the rear of the vehicle to engage the lifting bar of a container or load platform and to draw the container onto the vehicle. It is known to provide the hook with a safety lock to prevent the lifting bar from unhooking once the container or loading platform has been loaded. In the past these arrangements have either tended to rely on gravity to close the safety lock and thus have been prone to jamming due to rust, dirt etc, or they have required an actuator to be provided to open the safety lock. European published Application 0377491 discloses an arrangement in which the hook is pivotally mounted at the end of the lifting arm and pivots behind a locking projection.The pivotal mounting of the hook is considered to interfere with the structural integrity of the arm and hook and may make it more difficult for the operator to manoeuvre the hook onto the locking bar. A need therefore exists for a locking hook assembly which at least mitigates some of the problems associated with the above arrangements.

Accordingly, in one aspect this invention provides a locking hook assembly for a lifting arm which in use is movable through a loading cycle to load a container or other load platform onto a support structure, said locking hook assembly including a hook fixed with respect to the adjacent portion of said lifting arm for engaging in use a lifting bar or the like on the container or load platform, and a closure element movable to at least partially close the mouth of said hook, said closure element having drive surface means for being engaged in use by the container or load platform during the latter part of the loading cycle to drive the closure element towards a closed position which prevents or hinders the hook from unhooking from- the lifting bar or the like.

The assembly preferably includes bias means such as a tension spring urging the closure element towards an open position.

The closure element advantageously is mounted for pivoting movement relative to the hook and preferably comprises a pair of closure plates provided one to either side of the hook.

The drive surface means preferably comprises projection means associated with said closure element and arranged adjacent the hook for being engaged by an adjacent surface of the container or load platform during the latter stage of the loading cycle.

Although the locking hook assembly may find applications elsewhere it is mainly intended for use in a cargo handling system for loading containers and load platforms onto or off a vehicle. In typical such arrangements the container is loaded from the ground to the rear of the vehicle and the lifting arm pivots horizontally. For such a system, the hook means is preferably forwardly open and the projection on the closure element preferably projects rearwardly when in an equilibrium position. In these types of system, the container or loading platform preferably closes the closure element as it moves through the final arc of about 20 towards the horizontal.

In this specification the terms upper, lower, forward, rear etc. refer to the system when it is in its loaded position.

Whilst the invention has been described above, it extends to any inventive combination of features set out above or in the following description.

The invention may be performed in various ways and two embodiments thereof will now be described, by way of example only, reference being made to the accompanying drawings, in which:- Figure 1 is a schematic side view of a vehicle cargo handling system including a locking hook assembly in accordance with the invention, showing the lifting arm at the beginning, intermediate and end stages of the loading cycle, Figure 2 is a side view of a first embodiment of locking hook assembly for the arrangement of Figure 1, with the locking plates shown in the closed position (solid lines) and open position (broken lines), Figure 3 is a rear view of the locking hook assembly shown in Figure 2, Figure 4 is a side view of a second embodiment of locking hook assembly forth arrangement of Figure 1 with the locking plates shown in the open position (solid lines) and closed position (broken lines), and Figure 5 is a rear view of the locking hook assembly shown in Figure 4.

Referring initially to Figure 1, the basic handling system 10 is constructed in accordance with our own ROLONOF (TM) system. This comprises a cranked gooseneck lifting arm 12 of L-shape and having a lifting hook 14 at its upper end.

The hook is sized to receive the standard lifting bar 15 provided on many containers. The lifting arm 12 is slidably mounted in an intermediate frame member 16 which is pivoted at 18 to a pair of radius arms 20, themselves pivoted at 22 to the vehicle chassis. A pair of jacks (not shown) pivots the intermediate frame member 16 and thus the lifting arm 12 about the pivot 18 between the extreme loading/ unloading position A of Figure 1 and a position C where the intermediate member lies horizontal, forwardly of the pivot 18.

Likewise, a jack (not shown) slides the lifting arm relative to the intermediate frame member 16 forwardly to move it to the fully loaded position D. The jacks can also be operated to tip a container.

In a loading cycle the lifting arm 12 is moved to position A and hooked onto the lifting bar 15 of a container or platform 17. The intermediate frame member 16 and the lifting arm 12 are then pivoted about pivot 18 to draw the container or platform onto the vehicle, via an intermediate position B to a horizontal position C and then the lifting arm is extended forwardly to push the container or load platform home, D.

Referring now to the first embodiment of locking hook assembly shown in Figures 2 and 3, the lifting hook 14 is provided with a pivot pin 26 which supports two locking plates 28 one to either side of the hook 14 and spaced therefrom by a respective pivot plate 30. The locking plates are connected by bridge pieces 32 to form a single unitary weldment 34 having a jaw 36 which pivots about pin 26 to open and close the mouth of the hook 14. Two tension springs 35 extend between pegs 37, 39 on the weldment 34 and the lifting arm 12 respectively to urge the weldment 34 towards the open position shown in dotted lines in Figure 2.

The locking plates each include a rear flank portion 29 which together define a region projecting rearwardly of the hook 14 when the weldment 34 is in the open position.

In use, the handling system is backed up to a container and manoeuvred to engage the lifting hook 14 with the lifting bar 15 of the container, with the hook 14 in the open position. The container is then drawn onto the chassis and when the lifting arm reaches position B, the front wall 38 of the container (see Figures 1 and 2) engages the rearward projection 29, and further loading movement brings the arm closer to the container's front wall 38 which thus urges the portions 28 to pivot the weldment 34 to close the hook 14, as shown in Figure 2.

Unloading follows a reverse cycle.

Referring now to Figures 4 and 5, the second embodiment is similar to the first embodiment, except for the profile of the lifting hook 44, and so like parts are given like references and will not be described in detail again. Thus, the locking assembly includes two locking plates 28 biased to an open position by two springs and, when in the open position, the plates 28 defining a rearwardly projecting region 29. The region 29 is engaged by a forward face 38 of the container or loading platform as the lifting arm 12 nears the end of the loading cycle and thereafter is driven by the forward face 38 to close the locking plates around the lifting bar 15 to reach the locked position shown in broken lines in Figure 4.

Whilst described in conjunction with a rigid L-shaped lifting arm it will be understood that the above arrangements could also be used with those lifting systems having L-shaped arms whose limbs may be pivoted or otherwise moved with respect to each other.

Claims (11)

1. A locking hook assembly for a lifting arm which in use is movable through a loading cycle to load a container or other load platform onto a support structure, said locking hook assembly including a hook fixed with respect to the adjacent portion of said lifting arm for engaging in use a lifting bar or the like on the container or load platform, and a closure element movable to at least partially close the mouth of said hook, said closure element having drive surface means for being engaged in use by the container or load platform during the latter part of the loading cycle to drive the closure element towards a closed position which prevents or hinders the hook from unhooking from the lifting bar or the like.

2. A locking hook assembly according to Claim 1, which further includes bias means urging the closure element towards an open position.

3. A locking hook assembly according to Claim 2, wherein said bias means comprises one or more springs.

4. A locking hook assembly according to any preceding Claim, wherein the closure means is mounted for pivoting movement relative to the hook.

5. A locking hook assembly according to any preceding Claim, wherein the closure means comprises a pair of closure plates provided one to either side of the hook.

6. A locking hook assembly according to any preceding Claim, wherein the drive surface means comprises projection means associated with said closure element and arranged adjacent the hook for being engaged by an adjacent surface of the container or load platform during the latter stage of the loading cycle.

7. A cargo handling system for loading a container or other load platform onto or off a vehicle, comprising a lifting arm including a hook assembly and being mounted for movement in at least a pivoting sense about a generally horizontal pivotal axis through a loading cycle between a loading position in which the hook assembly may engage the lifting bar or the like of the container or other load platform and a loaded position in which the container or the load platform is drawn onto the vehicle, the locking hook assembly including a hook fixed with respect to the adjacent portion of said lifting arm for engaging in use a lifting bar or the like on the container or load platform, and a closure element movable to at least partially close the mouth of said hook, said closure element having drive surface means for being engaged in use by the container or load platform during the latter part of the loading cycle to drive the closure element towards a closed position which prevents or hinders the hook from unhooking from the lifting bar or the like.

8. A cargo handling system according to Claim 7, wherein the hook means is forwardly open and the projection on the closure element projects rearwardly when the closure element is in an equilibrium position.

9. A cargo handling system according to Claim 7 or 8, wherein, in use, the container or loading platform closes the closure element as the lifting arm moves through the final arc of about 20O towards the horizontal.

10. A locking hook assembly, substantially as hereinbefore described with reference to, and as illustration in, any of the accompanying drawings.

11. A cargo handling system, substantially as hereinbefore described with reference to, and as illustration in, any of the accompanying drawings.