The present invention relates to a method to tightening and lock an openable lid in a wall section of a storing container and an arrangement of locking bar to perform said method.

Storing containers to be placed on pallet is often a part in a logistic system to transport and handle of goods. Foldable storing containers have the advantage of taking up less space by return transport.

The advantages of the present invention shall be described in connection to a manufacturing line at an industrial plant where different details being parts of a manufactured product are stored in pallet supported containers along the manufacturing line. Often the details have been manufactured in another location and are transported in their containers to the place for production. Logistic advantages are obtained by transporting and storing the details in the one and same containers from manufacturing and all the way to a manufacturing line.

After manufacturing or storing the containers with the details are transported for production and may be positioned at a conveyor line. The stored and transported details are picked out from the containers for assembling. To start with the details are manually picked up from the opened container and along with the using of the details and when the level of details in the containers being lowered it will be more time consuming and tricky to lend down to pick up the details. In this connection it is of an advantage if it is possible to reach the details in the containers from openings in the side walls of the container. These openings must be closable and also be sealed of against weathering.

This is achieved by using an openable and closable or lockable lid arranged in an opening in a wall section of the container.

The main purpose of the present invention is to obtain a method and a locking lid arrangement to snap in and lock an openable and closable/lockable lid in an opening of a wall section of a storing container, which lid easily can be opened when needed to achieve an easy access to the details stored in the container.

An other purpose is to achieve a sealing bar arrangement which can be attached on a lid arranged in an opening of a container making it openable outwards, seen from within the container and lockable against movement inwards into the container.

Yet another purpose of the invention is to achieve a sealing bar arrangement between the lid and the wall section performing less resistance towards closing com- pared to opening and which very clearly will snap into its locking position when the lid is closed.

Still an other purpose of the invention is to obtain and use a transmission mechanism by an interaction between the locking bars being in force at the clamping of the lid to build up a strain between the lid and the wall sections of the storing container at both sides of the lid, which strain will at least partially be used to safely lock the lid in its closed position.

Yet another purpose of the invention is to achieve a locking bar arrangement which at least partially is capable of taking up the strain by an inner plastic deformation.

Another purpose of the invention is to obtain a surface design of interacting surfaces of the locking bars having an increased friction coefficient at a mutual movement between the locking bars in an opening and separating direction.

The above mentioned purposes are obtained by giving the invention the characterizing clauses mentioned in the claims.

The invention will now be described in connection to an embodiment shown on the accompanying drawings, where

Fig. 1 is a diagrammatic view of an open lid in the wall of a storing container,

Fig. 2 is a diagrammatic view according to fig. 1 but in a closed, sealed and locked position,

Fig.3a - Fig. 3e are cross sectional views of a pair of locking bars in an introducing, interactive stage when closing the lid and in a fully closed position of the lid respectively,

Fig. 4 is a diagrammatic view of a pair of locking bars in a mutual biased position during closing and opening of a lid, and where

Fig. 5 is a diagrammatic end view of the pair of locking bars shown in fig. 4.

In fig. 1 two pairs of locking bars 3a, 4a and 3b, 4b are shown between the edges of an opening of a wall section 2b of a container and the side edges of a lid 1. The locking lids have especially designed and mutual interacting surface profiles with projections and recesses b, c. In a closing process these surface profiles will be forced against each other (see also fig. 3) to finally end up in the position shown in fig. 2 in a closed or locked position. The reference a is a locking tab on the locking bar 3 which in a completed closed position will lend towards the outside of the in- teracting locking bar 4. Here a small recess in the side of the locking bar 4 has been hinted. This recess will take up the locking tab in forming a smooth outer side. In a mutual movement of the locking bars the projections and the recesses b, c will exert a pressure between the lid 1 and the wall sections 2b. The locking bars and their projections and the recesses may be dimensioned and chosen so that the exerted pressure to a certain degree still exists in the closed position. In a normal use this pressure is not needed but may be of advantage when using a locking tab to increase a sealing action between the bars and thus also between the out side and the inside of the container.

Fig. 3a - 3e show the process of action between the locking bars 3, 4 during an ongoing closing of a lid (not shown), where a strain between the lid and the wall sections is excluded in the fully closed position (fig. 3e) of the lid. Here the locking bar 3 has been shown in a stationary position during the complete closing process to more easily explain the principle of the interaction of the locking bars during closing. In this context it shall be mentioned that the mutual movement of the closing bars 3, 4 during closing takes place during an angular movement where the between the projections and the recesses a, b of the bars will be introduced continuously and is changed along the full length of the bars.

Thus a projection b on a first locking bar 3 will exert a force on a corresponding projection c on another locking bar 4 where the introducing phase is shown in fig. 3 a. The procedure will continue during a successively decreasing opening angle and if the projections have a progressively increasing height a higher strain is built up between the lid and the wall sections compared to not having this increased height. From the mutual position of the locking bars 3, 4 shown in fig. 3c where the highest strain is achieved between bars and the lid/wall sections, a resulting assisting strain will be exerted in the closing direction during a continued movement towards a fully closed position, whereby an active snap in action to a closed or locked position between the bars 3, 4 is achieved.

An opening of the lid 1 will initially demand a relatively high force. This is also the case if the profiles of the projections and the recesses are symmetric, that is the interacting mutual angles between the locking bars are equally big when closing as when opening the lid 1.

During closing the distance of movement of the lid is used to build up and also overcome the strain, but initially an essentially greater part of the strain mobilized by the mutual interacting locking bars needs to be overcome when initiating an opening of the lid. Often is seen as an advantage if the force needed to open is high. This will stop an unintentional opening of the lid. It is possible to adjust the opening force by choosing a more flat angle of interaction between the projections and the recesses of the locking bars. In such a case also the snap in action towards a fully closed position will be less markedly.

The factors taken up in a calculation for dimensioning and for choose of material to the closing bars will partly depend on properties of the wall sections and the lid and partly on how the walls of the storing container is supported, the size of the walls and how much of the wall surface that is taken up by a lid opening.

It is suppressed that the height and the depth respectively of a projection and a recess at a locking bar may be depended of the position of the locking bar that is the height may vary along the bar.

The man skilled in the art may here experiment with different heights and depth respectively at pairs of locking bars having in mind that their profiles must cooperate to obtain different opening and closing characteristics. Both of the locking bar pairs should advantageously have the same design of the profile curvature. For some uses where an increased locking action is preferred onto a closed lid it is possible to design a special micro surface structure to the interacting surfaces. This micro surface structure has very small barbs or biased projections in a size clearly less than 0, 1 mm. In closing direction the biased protrusions slide over each other without creating any markedly resistance but where the projections, in an opening direction of the lid will give an essentially greater resistance and thus will increase the locking action. Of course the lid is still openable, but it takes an increased force to open it, at least initially.

The invention is not restricted to the shown and described embodiments, but modifications can be done within the scope of the attended claims.