GB2073149A - Locking Device for a Foldable Container - Google Patents

Abstract

A rigid load carrying platform 1 having at each corner, or end, a post 2 which is attached pivotally at 3, 4 to the platform. Each post can be folded down adjacent to the platform by rotation about the pivots. The structure may be maintained in the upright position by means of a generally shaped conical pin which bridges between rigid projections at each corner of the platform, and the base of the pivotal posts via apertures made in the projections and pivotal posts. <IMAGE>

Description

SPECIFICATION Locking Device for a Folding Container This invention relates to a container or load carrying platform for the use of transportation of goods.

It is common to load goods into ridgid containers of a standard size, shape and strength.

At each corner of the container is a fitting which enables the containers to be handled, stacked one upon another, secured and transported by compatible standardised equipment, such as trucks, cranes, rail waggons and ships. The position of the corner fittings is essential, and should be accurately maintained, for the container to remain compatible with the related standard equipment.

It is sometimes desirable to provide a container which when empty of cargo, can be folded down to a fraction of its erected size, and then transported more conveniently or stored with less bulk. There are a variety of folding containers which in their erected state may have end and/or side walls and/or roofs which form a structure conforming to the standard container requirements and have ridgid corner fittings. The parts of the structure which are foldable must when erect, be held ridgidly in position by some means or other if the container is to be satisfactorily compatible with other containers.

A typical folding structure of a folding container is provided by members being connected pivotally to a platform rectangular base structure. The pivoted structure is raised to the erect position and there is locked by some mechanism against folding down again onto the base. The mechanism might be in the form of a cylindrical rod which is slid along an axis parallel to that of the pivot pin into cooperating and aligned holes in the basal part and the folding structure. When engaged between the holes, the rod prevents the structure from rotating about the pivot. Because of the climatic environment in which the containers must operate, large clearances are desirable between the rod, or other mechanism and its mating components, and the holes when in the locked position, in order to prevent seizure through corrosion, dirt or friction.

However, conversely it may be necessary to have a tight fitting mechanism to maintain the structure in the ridgid configuration required of standard containers. In this instance, seizure of the locking mechanisms does occur and difficulty in releasing the mechanisms, and thereby folding the containers, is experienced.

A second common feature of folding structures in containers is the abutment that is provided for the members to lean against. The position of the abutments is such as to maintain the structure in the prescribed ridgid stance against the handling forces that may be imposed upon it but in directions opposite to the forces resisted by the locking mechanism. It will be seen later that the present invention may obviate the need for accurately positioned abutments thereby reducing manufacturing costs and setting up difficulties, by resisting forces alone that would have been shared by the locking mechanism and the abutment.

It is an object of the present invention to provide a locking device for a folding container structure which can be engaged and disengaged under adverse operating conditions, and secure the structure in a ridgid position when engaged. It is another object of the present invention to secure the structure of a folding container in the erect position without the need of an abutment.

According to the invention there is provided a rectangular and ridgid platform base to which is linked by means of pivots or other means, a number of structures. The structures may be folded on top of the base when the container is empty, and raised to a position substantially vertically and there locked in place to form the ridgid rectangular box profile of a standard container. Typically the structures are connected pivotally to the basal part and are erected through an arc about the pivot. When the structure reaches the erect position, it abuts part of the base structure and can rotate no further. A locking mechanism may then be engaged with the folding structure and the base to link the two ridgidly together. The position of the locking mechanism may be in a number of locations and alignments according to the structural and geometric requirements of the container.It is within the locking mechanism that the present invention is concerned whereby there is provided a conically shaped pin which bridges between the moving and the fixed portions of the folding container thus preventing collapsing of the structure until withdrawn.

In order that the invention may be fully understood and readily carried into effect, a prefered embodiment thereof will now be described by way of example only with reference to the accompanying drawings.

Figure 1 is a perspective view of an erect folding container.

Figure 2 is a side elevation of a stack of folded containers in which the structural members have been each folded onto the base.

Figure 3 is a detail of the bottom corner of a container shown in Figure 1 broken away from the main container with the locking pin shown suspended about to be inserted into the locking position.

Figure 4 is a similar view to that of Figure 3 but with the structure in the folded position and the locking pin removed.

Figure 5A is a sectional drawing showing the pin inserted fully into the erect structure with the supporting plates cut away for clarity of the internal workings.

Figure 5B is a similar view to that of Figure 5A but with a different arrangement of the base structure.

Figure 6 is a sectional view of another arrangement whereby the alignment of the locking pin is more radial to the pivot rather than parallel.

Figure 7 is a drawing of an alternative conical pin combination having a number of parts to it's construction shown inserted into a cut away portion of the pivoted structure and platform base.

Refering to Figure 1 of the drawings. There is shown a 'container' which comprises a ridgid rectangular platform base 1 constructed of steel and timber for supporting the cargo. At each corner there extends upwards a corner post 2 at the top of which is a standard corner fitting 1 3. At the bottom corner of the base 1 is a similar corner fitting 1 3. The position of the fittings 13 is determined by international standards and should remain ridgidly located under the handling end transport conditions expected of a container. At the lower end of the corner post 2,. is a plate 3 ridgidly secured to it.The plate 3 passes between two plates 5 and 5' which are ridgidly secured to the base 1 a pivot pin 4 is inserted freely through holes bored through the plates 3,5 and 5' so that the corner post 2 is connected pivotally to the base 1. Movement of the corner post 2 towards the base 1 will cause the post 2 to rotate about the pivot pin 4 and eventually come to rest on or adjacent to the base 1 as indicated by the dotted lines 2' and the arrow 21.

The corner posts 2 are at one end of the container linked by a structural member 22. This member 22 is by way of example to illustrate that the corner posts 2 may be separate and free standing, or joined by some additional and optional structure similar to 22. In Figure 1 (or the enlargement in Figure 3) one can see in the erect position, the corner post plate 3 may abut a plate 23 which is ridgidly connected to the base 1, corner fitting 1 3 and plates 5 and 5'. This plate 23 prevents further rotation of the piate 3 vihich would otherwise continue through St's erecting arc and fall outside the plan profile of the base 1.

Adjacent to the pivot pin 4 are additional holes whose axis 24 is substantially parallel, in this example, to that of the pivot pin 4. It will be shown later that this alignment and location may vary from that shown.

In Figure 2 of the drawings, a plurality of the containers shown in Figure 1 can be seen stacked one upon another in their folded form. The comer posts 2 have been folded down adjacent to the base 1 from their erect position shown in dotted outline 25. Three other containers 6,7,8 lie beneath the first. In this stack, the containers can be transported or stored at a fraction of the cost of a similar operation with erected containers.

Figure 3 illustrates a detail of one bottom corner of an erected container showing corner post 2 and base 1 broken away from the main container. A pin 9 can be seen suspended by some means not shown here. The pin has an axis 14 and a surface 16 which is shaped conically about the axis 14. The sharp apex of the cone is not required for the purposes of the pin 9 so that it has be cut off to produce a flat topped conical shape of pin 9 known as a frustum, but will be refared to in this document as the more commonly known cone.

The corner post plate 3 can be seen erect and in abutment with plate 23. l Holes 10 and 11 are made in the plates 5 and 3 respectively. A third hole 12, but not shown is made in plate 5'.

Figure 4 shows the same directional view as Figure 3 but with the corner post 2 and plate 3 folded down onto the base 1. The holes 10,1 1,12 can be seen more clearly. Because the plates 3, > 5,5', have some thickness, so too have the hole surfaces 10,11 1.12, which in this example extend for the width of the plates 3,5,5'.

Figure 5A shows a vertical section taken through the erected corner post 2,3 passing through the hole axis 24. The pin 9 has been inserted so that it's surface 1 6 is in contact with the faces of the holes 16,1 1 and 12. The three axes 24,26 and 14 all lie concentricaily and the plate 3 has been lifted away from abutment with plate 23. The faces of the holes 10, 11 and 12 thus make contact with the cone surface 1 6 substantially around its whole circumference. In this position, the plate 3 and the plates 5 and 5' cannot substantially move relative to one another.

In this example, it can be seen that the holes 10,11 and 12 are shaped conically about the axis 24. Thus the surface 1 6 touches a large surface of the holes and so reduces the pressure on the surfaces at the points of contact when the plates 3 and 5 and 5' are under load. When the pin 9 is withdrawn to position indicated by the dotted outline 9', a gap quickly opens up between surface 16 and the surfaces of the holes 10,11 and 12 because of the conical shape of the pin and holes. Thus in operation effects of dirt and corrosion which prevent sliding motion between the pin 9 and holes 10,11,12 are substantially reduced due to the parting of the surfaces brought about by their tapered profile.

Figure 5B shows a similar section to Figure 5A and is in all respects the same except for the clearance between plate 3 and the abutment plate 23. Plate 3 is seen to make the abutment before the axis 26 reaches concentricity with axis 24. Thus the pin 9 when inserted makes contact will the upper surfaces of the holes 10,12 and the lower surface of the hole 11. As the pin 9 is pushed tighter inwards into the tapered holes 10,11,12 contact with the plates 3 and 23 is made firmer.

It may be seen that under load or carriage of the container, a tapered or conical pin may tend to move out of engagement. It is envisiaged that there would be attached to the pin 9 either directly or indirectly some means to prevent its disengagement until so desired. Similarly, a mechanism may be attached to the pin 9 for the purpose of increasing the mechanical advantage of a man who is inserting or withdrawing the pin 9. In this way a tighter fit might ensue. The same mechanism might be used to retain the pin 9 in the desired position.

As load is applied to plate 3 as a result of handling forces applied to the corner post 2, movement between the plate 3 and the plate 5 and 5' which are secured to the base 1, is prevented by either the abutment plate 23, for forces in a substantially downward direction or by the pin 9 supported by the holes 10,12 pressing against the hole 11 in the plate 3. It can be seen that correct positioning of the corner post 2 is dependant upon the abutment plate position and the correct location of the holes 10,11,12. In Figure 5A since there is clearance under operational loads between the plate 3 and plate 23, correct location of the corner post 2 is governed only by the holes 10,11,12, and their alignment.

Whereas in this example, there are two plates 5 and 5' across whichthe pin 9 bridges, it would be feasible and it is anticipated that the pin 9 may be cantilevered out from plate 5 to engage in similar fashion and operation to the previously described example but that plate 5t would no longer be present in the base structure 1.

Figure 6 shows a different example to illustrate that the alignment of the pin 9 is not dependant on its axis 14 being parallel to that of the pivot pin 4, for effective operation. in the example a corner post plate 29 is pivoted about a pin 4. The plate 29 is ridgidly attached to a corner post 2 and folds as the previously described examples onto the base 1. A plate 28 is ridgidly attached to the base 1 and a hole 21 is bored in the plate 28. This hole 21 falls closely into alignment with the hole 20 formed in the plate 29 when the plate 29 is lifted to it's erected position. The pin 9 being of conical profile can enter the holes 21 and 20 which are similarly conical in form, and as with the previous example may share an axis and conical surface.Since the surface 1 6 of the pin 9 shares a substantially similar surface to the holes, 20,21, a tight fit may be achieved. Alternatively, the pin 9 might work in conjunction with an abutment plate as exampled in Figure 5B, whereby plate 28 might abut plate 29.

In Figure 7 of the drawings, there is shown an alternative shape of conical pin. It is not necessary for the pin to be of uniform conical shape for the effect of reducing clearance between it and the holes into which it is to be inserted, to take place.

It can be seen in this example that the pin is divided into three portions 1 7,18, and 19. The plates 3,5 and 5' are shown in part with their respective holes 11 ,1 0 and 12. The pin 9 is shown fully inserted. Part 1 7 of the pin 9 has a sharp conical end; part 18 is cylindrical and as such has no wedging action when entering it's hole 11; and part 1 9 has a lesser angle to it's conical surface than surface 17. In this example, a clearance is allowable between the locking pin 9 and the hole 11, although the overall clearance in the locking mechanism is still reduced compared to a cylindrical pin throughout due to the closing action of the conical surfaces onto the hole surfaces.

In operation, loads will act upon the pin 9 in all directions particularly perpendicular to the axis 14. These loads which result from handling the container through the the corner fittings 13 can be immense, and because of the relatively larger length between the corner fitting 1 3 and the pivot 4, and the locking pin 9 and the pivot 4, these handling forces are multiplied several times over.

For the same distance reasons, the pivot and the pin 9 must be a tight fit if the corner fitting 13 is not to move around and out of standard position.

It might be possible to manufacture the pin 9 in a shape which is a rectangular section wedge, however the cost of manufacturing a set of concentric rectangular tapered holes to interface with the wedge would be prohibitive. Further more, the virtue of a circular section is that it presents a uniform bearing face to the support hole whatever the direction of the perpendicularly applied forces, whereas a rectangular section would present an inclined face against most forces perpendicular to its axis.

Claims (12)

Claims

1. A goods container comprising a platform base to which are connected by pivotal means, structural members which when raised to a substantially erect position may be used for cargo retention, container handling or stacking of other containers upon it, and which said members may be folded down onto or adjacent to the platform base thereby reducing the space occupied by erected form of the said goods container, and means whereby the said members may each be held in the erect position comprising apertures in the pivotal members which closely align with apertures in the basal part of the container and into which apertures a pin may enter to bridge the said basal part and the said pivotal member and thereby resist rotational movement of the member about its pivot, and in which said pin is of substantially conical form whereby continued insertion apex first into the said apertures may continually reduce the clearance between said pin and apertures until the limits of the geometry have been reached.

2. A goods container according to claim 1 wherein the shape of the said pin comprises one or more portions each having a surface of generally cylindrical or conical form except that one or more portions be of conical form although not necessarily having the same angle of slope as another conical portion, and in which the conical portions may be frusta.

3. A goods container according to claim 1 wherein the said pin is of conical frustum form.

4. A goods container according to claim 1,2 and 3 wherein the said apertures are of similar form to that of the shape of the said pin so that substantial surface contact between the pin surface and the surfaces of the apertures may take place when the pin is inserted and relative movement of the said pivotal members and the base takes place.

5. A goods container according to claim 1,2,3 and 4 wherein the axis of the said pin is substantially parallel to that of pivot.

6. A goods container according to claims 1,2,3,4, wherein the said axis of the said pin is substantially radial to the axis of the pivot.

7. A goods container according to claims 1 2,3,4, wherein the said axis of the said pin is in any location or alignment suited to the structural and geometric requirements of the container.

8. A goods container according to any of the preceeding claims 1 to 7 wherein the structural members are raised to the said erect position and there make an abutment with a member ridgidly attached to the said basal part thus preventing further rotation of the said pivotal member about the pivot.

9. A goods container according to claim 8 wherein insertion of the said pin displaces the pivotally connected member into firmer contact with the said abutment member thereby forming a cooperating part of the support of the said pivotal member against movement.

10. A goods container according to claim 8 wherein insertion of the said pin displaces the pivotally connected member away from contact with the said abutment to form a clearance between the said member and the abutment thereby ensuring movement of the pivotally connected member is restricted by the said pin without assistance from the abutment.

11. A goods container according to any of the preceeding claims 1 to 10 wherein mechanical means is provided to assist in the insertion, withdrawal or retention of the said pin.

12. A goods container according to any of the preceeding claims 1 to 11 wherein the structural members are attached to the base by some means other than pivotally.