GB2220636A

GB2220636A - Adjustable corner fitting for receiving twistlock

Info

Publication number: GB2220636A
Application number: GB8816495A
Authority: GB
Inventors: Martin Clive-Smith
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-07-12
Filing date: 1988-07-12
Publication date: 1990-01-17
Also published as: GB8816495D0

Abstract

A folding shipping container of the type called a flatrack comprises a horizontal rectangular platform base with vertical posts (6) at each corner. When cargo is placed on the base the posts rotate inwards causing a change in position of handling apertures (7) at the top of the posts. Adjustment means (13) maintain the apertures in the position required by handling devices, e.g. twistlocks (37) when there is or is not cargo placed on the base. As shown, a block (13) is movable along sides (36) of aperture (7) by a rod (20) with a spring-loaded over-centre mechanism. Thus, if loading the flatrack bends post (6) leftwards, block (13) is moved leftwards so that aperture (7) is restored to its original position, for co-operation with twistlock (37) on spreader (16). <IMAGE>

Description

Title: ADJUSTABLE CORNER FITTING FOR A CARGO CARRIER.

In the field of shipping containers there is a type of special container called a flatrack which comprises à horizontal rectangular platform base with vertical corner posts at each corner. The corner posts can sometimes be hingedly attached to the base. They can either be locked in the vertical position or the corner posts can be unlocked and folded down to the base for economical storage and transport of empty containers. Other types are of similar construction but have fixed enwalls which cannot fold down.

Typically, at the top of each erect corner post of a flatrack there is a hollow box shapped corner fitting with handling apertures formed in its top surface. Special rigid lifting frames hung from cranes and the like can link into the apertures to enable lifting of the container. It is important for the handling apertures to be maintained accurately in position by the container structure in a geometrical relationship one to another to enable rigid handling devices to link to them.

However the problem arises that when heavy cargo is placed on the base, the base deflects downwards and the erect corner posts which are attached at the ends of the base rotate inwards. The corner post rotation causes the distance between the top corner handling apertures to shorten which in turn can make the location of lifting frames in the apertures difficult or even impossible.

The conventional solution to maintaining the top handling apertures in place is to ensure that the rigidity of the platform base is sufficient to minimise deflection between the unladen and laden conditions such that corner post rotation and the resultant handling aperture movement is kept within tolerable limits. However to make such a base rigid means either making it deeper, thereby taking up valuable cargo space, or building in extra rigid material such as steel plate, thereby limiting the payload.

The present invention provides a corner fitting for a cargo carrier in which the handling aperture can be altered independantly of any movement of the corner fitting in order to meet the interface requirements of handling devices.

A preferred embodiment of the invention will now be described with reference to the following drawings in which: Figure 1 shows a perspective view of a collapsible flatrack container.

Figure 2 shows the side elevation of a flatrack with lifting frame suspended above.

Figure s shows the same elevation as figure 2 but with a cargo placed onto the flatrack.

Figure 4 shows an enlarged perspective view of a top corner fitting with lifting fram suspended above.

Figure 5 shows the view as figure 4 but with a cargo placed onto the flatrack so as to deflect the corner fitting inwards.

Figure 6 shows a section through the side elevation of the top corner fitting revealing details of the internal workings.

Figure 7 there is seen a section of the end elevation of the top corner fitting revealing details of the internal workings.

Figure 8 shows the plan view of a top corner fitting of an alternative arrangment showing a complete moving aperture.

In figure 1 there is seen a typical collapsible flatrack comprising a base 1 with floor 2, end rails 3 and side rails 4, and a wall 8 at each end with posts 6. At each corner of the flatrack is a box shaped corner fitting 9, 1 which has formed in its sides, side apertures 5. Fitting 9 has an aperture 7 formed in its top surface to accept the known hooks and twistlocks of handling devices. The walls 8 are locked in the erect position shown by a mechanism 11 which when released allows the walls 8 to fold down onto the base 1 about arrows ''. Typically the materials of construction of the flatrack are a high strength welded steel with a floor 2 of timber.

In figure 2 there is seen the side elevation of a flatrack 17 as shown in figure 1. There is no cargo resting on the base 1 and the corner fittinges 1 are resting on the ground 15 with the base 1 clear of other support. The posts 6 are erect. The distance between the apertures 5 is denoted by letter D. A rigid lifting frame 16 can be seen hanging from wires 18 from an unseen crane above the flatrack 17. There are twistlocks 37 projecting from the frame 16 about to enter the apertures 7 in the top of the corner fittings 9. The distance between the twistlocks 37 is substantially the same dimension D so that the twistlocks 37 can enter straight into the apertures 7.

In figure 3, a heavy cargo 14 has been placed on the base 1 and it can be seen that the base 1 has deflected downwards from the unladen base position 1' shown in dotted line. The posts 6 being attached to the base 1 have simultaneously rotated inwards from position 6' towards each other reducing the distance D to D'. The twistlocks 37 no longer line up simply with the apertures 5 and the frame 16 cannot engage for lifting with the flatrack 17 unless the posts 6 are returned to position 6' with distance D between apertures In figure 4 there is seen an enlarged view of corner fitting 9 clearly showing the top aperture 7 with a twislock 37 held in a frame 16 about to enter it. The aperture 7 shares the same centre line 1 of the twistlcok 37.

Moving to figure 5, the structure of the flatrack 17 has been deflected as in figure 3. The post 6 has been displaced so that the centre line 19 of the aperture 7 is no longer in line with the centre line 12 of the twistlock 37. The outer most end of the aperture 7 is formed by a block 13 which is supported by the body of the corner fitting 9. To enable the twistlock 37 to enter the aperture 7 the centre line 19 must be restored close to centre line 12. By movement of the block 13 to position 13', the centre line 19 of aperture 7 is now at 19' close enough to centrer line 12 of the twistlock 37 to allow easy entry.

In Figure 6 one can see a cross section taken through the twistlock 37 and corner fitting 9. The block 13 is seen to the outermost end of the aperture 7. Connected to bloc 13 is a bar which is pin jointed to post 6 at pin 21. The bar passes through a slot 22 formed in the bottom plate 23 in the fitting 9. By displacement of the bar 2 to position 2X' the block 13 is carried to position 1S' thereby causing the centre line 19 to shift to centre line 19'.

Generally when twistlocks 37 enters into fittings 9,16, large forces can be exerted on the apertures 7. So it is necessary to support block 13 against such forces. Vertical forces acting on block 13 are resisted by bar 2 and pin 21. In addition, lugs 24 projecting from bar 2 may be arranged to rest on bottom plate 23 when the block 13 is in its inner or outermost positions. The location and shape of the bar 2 is arranged so that is does not interfer with the space needed for the twistlock 37 when it has entered the fitting 9 denoted by dotted line 37'.

In figure 7 one can see the same fitting 9 in section looking towards the outer most part of the flatrack 17. Projecting from the block 13 can be seen fins 25 which rest in chamfers 27 typical of the shape of apertures 7 in fittings 9,10. No part of the block 13 projects above the top surf ace of the fitting 9. There are lugs 26 also forming part of the block 13. Thus the block 13 is located within the aperture 7 against imposed forces yet by suitable clearances between the block 13 and aperture 7 can be moved as required along the length of the aperture 7.

Several other means of movement of the block 13 can be realised such as provision of a horizontal handle 28 which projects out through the side of the fitting 9.

To keep the block 13 in place at one end or the other of the aperture 7, a variety of known retaining devices might be used. One such system is shown in figure 5 wherein there is a spring 29 which is held in tension between a pin 3Q mounted on the bar 2 and a second pin 3 mounted on the post 6. The line of action of the spring 29 can be seen to urge the bar 2 and thus block 15 to the right of the figure 5. When the bar 2 is moved to positon 2' the line of the spring 29 crosses over the pin 21 and now urges the block to the left of the figure 5.

Typically the size of the twistlock 37 is smaller than the aperture 7 so that provided that the ends 31, 32 of the twistlock 37 fall in line with the inner face 3 33' of the block 13, then the twistlock 37 can enter the aperture 7 even though there might be some tolerable displacement of the centre lines 12,19 from one another yet still allow entry of the twistlock 37 to aperture 7. Thus the 2 positions of the block 13 , 13,13', would in practice be acceptable.

It is envisaged that where the positon of the aperture 7 is need to be infinitely variable to reflect the gradual deflection of post 6, then block 13 might be continued around the whole perimeter of aperture 7 as a ring 34 and aperture 7 enlarged to aperture 35 to allow sliding movement of the ring 34 from one end of aperture 5 to the other. This is illustrated in figure 7 showing a plan view of the fitting 9.

Returning to figure 4 one can see that the twistlock 37 has typically parallel sides and curved ends 31,32. The curved ends 31,32 bear on the walls 36 of the aperture 7 and block 17X. Thus for good bearing of the imposed forces, the shape of the block 13 and walls 36 is similar to the curved ends 31,32 and sides of the twistlocks 37.

Since the block 13 is to move from one end of the aperture 7 to the other and thus present a different faces 33,33' to the twistlock 37, both faces 33 and 3S' are curved inwards to the centre of the block 13.

Other means of moving the blocks are envisiaged such as by rotation in any plane. More than one block as 178 might be provided.

Claims

1. A fitting for a cargo carrier which incorporates one or more handling apertures in which the handling aperture can be altered independently of any movement of the fitting in order to meet the interface requirements of handling devices.

2. A fitting as in claim 1 in which the fitting is positioned at any place on the cargo carrier as may be required by handling devices.

A A fitting as in claim t or 2 comprising a rectangular hollow bo" with an aperture formed through a surface of the fitting being suitable for receiving twistlocks and in which the aperture comprises a substantially rectangular slot there being mounted within the slot a block which can be moved from one end of the slot to the other thereby altering the geometry of the aperture.

4. A fitting as in claim 1, or . comprising a rectangular hollow bo with an aperture formed through a surface of the fitting being suitable for receiving twistlocks and in which the aperture comprises e. substantially rectangular slot and there being mounted within the slot a rectangular plate with an aperture formed in the plate to form a ring, the ring being movable within the slot thereby altering the position of the aperture.

5. A fitting as in claim 3 or 4 in which the block or ring is supported by fins resting on the body of the fitting.

6. R fitting as in claim 3, 4 or 5 in which the block or ring is partially supported by a bar, the bar providing the means to move the block or ring within the aperture

7. A fitting as in claim 6 in which the bar is pivotally mounted on the post and is retained at one end or the other end of the aperture by a spring acting on the bar.

8. A fitting as in claim 35 4, 5 or 6 in which the movement means comprises a handle being attached to the block or ring the handle projecting out through the fitting.

9. A fitting in claim 3,4,5,6,7 or 8 in which the block or ring is shaped to the profile of handling devices making use of the aperture.