EP3395711A1

EP3395711A1 - Bi-stable surface concave-convex-concave transition mechanism

Info

Publication number: EP3395711A1
Application number: EP17020185.9A
Authority: EP
Inventors: Jalil Badaoui; Rudolf Koopmans; Denis Cuche
Original assignee: Haute Ecole D'ingenierie Et D'architecture De Fribourg (heia-Fr)
Current assignee: Haute Ecole D'ingenierie Et D'architecture De Fribourg (heia-Fr)
Priority date: 2017-04-27
Filing date: 2017-04-27
Publication date: 2018-10-31

Abstract

An object comprising a least a part having at least a bi-stable behaviour in which said part is able to reach a first configuration or a second configuration, said first and second configurations being different from each other, wherein said object comprises triggering means (2, 4, 13, 24, 34) to induce a change from one of said configurations to the other of said configurations.

Description

TECHNICAL FIELD

The present invention concerns the field of devices and products using a part with bi-stable properties.
More specifically, the present invention concerns the field of products having a bi-stable part, for example boxes, closures, or shutters having a bi-stable lid, cap or surface for respective closing, locking or shutting of the product.

BACKGROUND ART

A bi-stable behavior is a physical effect that enables structures to reach two different shapes or configurations, both being stable. To obtain this effect, structures must be designed accordingly. Such bi-stable structures have then, unlike conventional structures, not one but two stable states or configurations. The structures can change elastically from one of the state/configuration to the other one by applying for example a force by a certain way on them, this change being completely reversible.
As a non-limiting example, by designing a surface in a well-domed shape, it is possible to give the surface a bi-stable behavior. In this case, the two configurations are given by a convex and a concave shape, which are both a stable state and shape of the object.
To change from the convex stable configuration of the surface to the concave one, it is necessary to apply a force, for example a pressure on the top of the dome. This physical effect or "snap action" is commonly called a "click-clack" effect.
One of the application known in the literature of this bi-stable behavior of surfaces is container lids. Containers having a bi-stable opening and closing mechanism, which is based on the shape of their lid, have been patented since the 1920s. These boxes are designed such that the lid can assume a convex or a concave configuration, and can be manually transferred between the two configurations and translates into a change of the angular position of the flange member leading to opening or closing of the box.
For example, the patent CH132764A discloses a metallic container made of two parts and having a circular deformable lid used as opening and closing system. Bi-stable lids could also be used for rectangular shapes as in patent US2024227A . Further US2012037654A1 discloses a bi-stable circular lid made of plastic and its corresponding container. DE102015103036A1 discloses a bi-stable circular lid made by thermoforming. US2014342056A1 concerns a container having a bi-stable lid being "over-moulded" in some area. EP1712485A1 and WO2014090399A2 are about bi-stable containers made of two parts and linked by a hinge mechanism.
Currently on the market, one can find containers, sold for example by the company Hoffmann Neopac as merchandising products, under the trade name Click-Clack ®. These containers are metallic, have a circular shape, made of two parts, opened, and closed with a bi-stable lid as explain herein.

SUMMARY OF THE INVENTION

Currently, in the known application of the bi-stable effect, e.g. bi-stable lids, for metallic boxes, the user presses with the fingers on the clamping flanges attached to the side of the lid to change from a concave shape to a convex one and to close the box with the bi-stable lid. To open the box, it is necessary to change the shape of the lid from convex to concave and this is done by imparting a force on the lid, for example in its middle thereby pushing the dome into the convex stable position. Once this position is reached, the clamping flanges are moved away from the lower part of the box and the lid maybe freely taken away and access to the box is possible.
This move and bi-stable behavior is possible with metallic lids but typically not with plastic ones because of their physical properties. Plastic presents a far lower Young modulus that compromises this operation by letting the clamping flanges flex under pressure and not allowing to change the shape of the lid in the absence of a trigger for that change. Accordingly, there is inherent reason why skilled persons will not consider the "click-clack" principle as being applicable to plastic boxes and in particular to plastic lids having even having a bi-stable behavior.
The fact that plastic and other similar materials (for example synthetic or bio-based soft matter materials) are unsuitable for such bi-stable applications therefore remains a common thinking in the art, even for other applications than boxes, closures, shutters, and similar products.
The present invention aims to solve this limitation to the use of elements that have a bi-stable behaviour made in materials that, at first sight, are not suitable for this purpose.
According to an embodiment, an idea is to use triggering means to render possible a bi-stable actuation of the concerned part, such as the lid, even if made of a plastic or other synthetic material.
Typically, the envisaged triggering means are called "actuators objects", and they are preferably integrated in the product.
Accordingly, the invention relates to a mechanism helping the convex-concave-convex change of position of a bi-stable surface. This mechanism is integrated to the system and comprise of an actuator object brought into contact or being part of the bi-stable convex surface. With this invention, we are able to change the shape of the bi-stable surface from the concave shape to the convex shape by applying a force on the same side of the surface with any materials including plastic.
In one embodiment, the invention concerns an object comprising a least a part having at least a bi-stable behaviour in which said part is able to reach a first configuration or a second configuration, wherein the first and the second configurations are different from each other, wherein the object comprises triggering means to induce a change from one configuration to the other configuration.
In an embodiment, the triggering means are linked to the part having a bi-stable behaviour and/or are linked to another part of the object.
In an embodiment, the triggering means is integrated into the object or added to the object or is a part of the object.
In an embodiment, the object comprises a closure, shutter or locking mechanism having a body and a part having a bi-stable behaviour forming said mechanism, wherein one of the configurations of the mechanism is a concave-shaped configuration and the other configuration of the mechanism is a convex-shaped configuration.
In an embodiment, the object is a box or container having a body and lid and the part having a bi-stable behaviour forms said lid, wherein one of the stable configuration of the lid is a concave-shaped configuration and the other stable configuration of the lid is a convex-shaped configuration.
In an embodiment, the lid is articulated or hinged on the body. Hence parts of the object may by attached to the object or be an integral part of the object. In an embodiment, parts of the object may be of different materials or of the same material.
In an embodiment, the triggering means comprise a raised part.
In an embodiment, the raised part is on the body and/or on the lid.
Preferably, the configurations are stable configurations.
Preferably, the object as defined herein and/or said part having a bi-stable behaviour are made of a synthetic or bio-based plastic material.
In an embodiment, the object described herein is made of a single part. Of course other constructions are possible.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative non-limiting embodiments of the invention are shown in the appended drawings in which

Figures 1 to 4 illustrate a first embodiment of the invention;
Figures 5 to 8 illustrate a second embodiment of the invention;
Figures 9 to 14 illustrate a third embodiment of the invention;
Figures 15 to 20 illustrate a fourth embodiment of the invention;
Figure 21 to 26 illustrate a fifth embodiment of the invention.

DETAILED DESCRIPTION

Figures 1 to 4 show a side view of a first embodiment of the present invention. In this embodiment, the invention comprises a first part 1 having a bi-stable behaviour. This part 1 can be a cover as a non-limiting example that has a first stable configuration illustrated in figure 1, for example a dome-shape. The invention further comprises a triggering means 2 that will trigger the change from one stable configuration to the other as will be explained hereunder.
Figure 2 illustrates a cut side view of the elements of figure 1, along the cut line A-A of figure 1.
In figure 2, a vertical arrow is illustrated that shows a force F1 that can be imparted, typically externally, to the first part 1 in order for said part to reach its second stable configuration as illustrated in figures 3 and 4.
More specifically, figure 3 illustrates a side view of the first part in its second stable configuration, for example reach by reaction to an applied force F1 shown in figure 2.
Figure 4 illustrates a cut side view of the elements of figure 3 in the configuration of figure 3, along the cut line A-A of figure 3.
The two vertical arrows in figure 4 illustrate a force F2 that may be applied to the first part 1, in order for this part to return to its first stable configuration illustrated in figure 1. However, these forces F2 alone are not sufficient and one needs the application of the first part 1 on the triggering means 2 in order to impart the change from the second configuration to the first, the triggering means applying a reaction force on the first part, but on a zone of the first part that generates the change to the other (i.e. first in this example) configuration.
Hence, according to the present invention, a force need only to by applied to two different places on the first part to allow its change from one configuration to the other.
Figures 5 to 8 illustrate a second embodiment similar to the first one, but in this embodiment, the triggering means 4 are part of the first part 3. For example, figure 1 illustrates a side view of a first part 3, which comprises second part 4 as triggering means.
Figure 6 is a cut side view along lines A-A of figure 5. As in figure 2, a force F1 is applied to the first part 3 so that it reaches its second configuration as illustrated in figures 7 and 8.
Figure 7 illustrates a side view of first part 3 in its second configuration.
As in the preceding embodiment, the two vertical arrows in figure 8 (side cut-view along A-A of figure 7) illustrate a force F2 that may be applied to the first part 3, in order for this part 3 to return to its first stable configuration illustrated in figure 5. However, these forces F2 alone are not sufficient and one needs the collaboration of the first part 3 with the triggering means 4 in order to impart the change from the second configuration to the first, the triggering means 4 applying a reaction force on the first part 3, but on a zone of the first part 3 that generates the change to the other configuration (i.e. first in this example).
Hence, again in this embodiment, according to the present invention, a force need only to by applied to two different places on the first part to allow its change from one configuration to the other as desired.
Figures 9 to 14 illustrates side and perspective views of another embodiment of the invention, for example the cover 10 of a box as described at the beginning of the present specification. The cover 10 comprises a lid part 11 which has a bi-stable behaviour rendering it able to reach two stable positions, i.e. to close or open a box on which the cover 10 is applied.
More specifically, the cover 10 also comprises a plurality of side clamping flanges 12 and triggering means 13 on the inside of the clamping flanges. The cover is illustrated with a plurality of flanges 12 (sixteen as illustrated in figure 10) but this number could be reduced or increased and is only an illustrative example. For example, considering the shape of the cover, three flanges are normally enough, placed every 120° for example. Even two flanges 12 would be enough to close a round box with this cover 10. In any case, the example given should not be considered in a limiting manner and other configurations are possible.
In figure 11, the actuating of a change of configuration is illustrated. For example, an external force F1 is applied to the lid 11 which has the shape of a dome, preferably in the centre of the dome and this force F1 allows the lid to reach a second configuration illustrated in figures 12 to 14 whereby the lid again is a dome shape but oriented downwards (figure 11 is oriented upwards). In this configuration, for example, a box closed by said cover 10 may now be opened.
To change the configuration and reach the one illustrated in figures 9 to 11, a force F2, illustrated by the arrows in figure 14, is applied to the flanges. The deformation of the flanges will then be reported on the lid 11 by means of the triggering means 13 such that, because of its bi-stable behaviour, the lid returns in its first configuration, as in figure 11.
In the example illustrated, each flange 12 comprises a triggering means 13, but is of course possible to reduce the overall number of triggering means. Theoretically, a single one should be sufficient and the necessary number may be determined depending on the configuration, the shape of the cover 10, lid 11, number of flanges 12, the materials used, and design specific criteria.
Figures 15 to 20 illustrate another embodiment of the present invention. This embodiment relates to a box with an articulated lid. Specifically figure 15 illustrates a side perspective view of the box 20 which comprises a body 21 and a lid 22 with a flange 23 and triggering means 24 placed inside the body 21. The lid 22 has a bi-stable behaviour as will be explained in the following description.
Figure 16 illustrates a side cut view of the box 20 and the lid 22 in an open position and first (stable) configuration of its bi-stable behaviour. This configuration can be seen in figure 16 where the lid has a dome shaped configuration in the direction of the inside of the body 21.
Figures 17 and 18 illustrate the closing of the lid 22 on the body 21 (perspective view and side cut view). The action of pushing on the flange 23 is not enough to move the lid 22 in its second configuration and this change is triggered by the triggering means 24 which are present in the body 21 under the shape of a wall, the top border 25 of said wall 24 applying a force against the lid and pushing the lid 22 towards its other (second) configuration, reached by the bi-stable behaviour of the lid 22.
Figures 19 and 20 illustrate in perspective view and side cut view respectively the box 20 in a closed state in which the lid 22 is in its second configuration, a dome shape oriented away from the body 21. The flange 23 allows to maintain the box 20 closed as illustrated in figure 20. To open the box, a force such as a pressure has to be applied on the lid 22, about at the centre of the illustrated cross and this force will push the lid 22 in its other configuration through the bi-stable effect and the box may be opened as in figure 18 and 15.
Of course, this is only an example of realization and modifications are possible. For example the wall 24 may be a part of the body 21, or added to the body, or may even be attached to the lid 22. In another variant, the wall 24 is formed from two parts, one being in the body 21 and the other on the lid 22.
Figures 21 to 26 illustrate another embodiment of the present invention with a box comprising an articulated lid. Specifically, in the perspective view of figure 21, one sees a box 30, with a body 31, an articulated lid 32 with a flange 33 and a slit 35 in the body 31. The lid 32 in a first configuration of its bi-stable behaviour as can be seen in the side cut view of figure 22, with a dome shaped lid 32 in the direction of the body 31.
Figures 23 and 24 showing a perspective view and side cut view illustrate the process of closing the box 30 by closing the lid 32 on the body 31. Figure 24 in particular shows the box closed but with lid 32 still in its first configuration with the dome shape towards the body 31. To push the lid 32 towards its other (second) configuration using it bi-stable properties, one applies a force on the flange 33, this force being transmitted to the lid 32 by the triggering means 34 which is between both parts (see figure 24). The effect of this triggering means is in accordance with the principles of the present invention to push the lid 32 to reach its second configuration and this configuration is illustrated in figures 25 and 26, showing a perspective view and a side cut view of the box 30 in closed state with the lid 32 having a dome shape directed away from the body 31. The slit 35 is used to allow the passage of means 34 as one can see in figures 24 and 26.
While this invention has been described in conjunction with a number of embodiments, it is evident that many alternatives, modifications and variations would be or are apparent to those of ordinary skill in the applicable arts.
Accordingly, it is intended to embrace all such alternatives, modifications, equivalents and variations that are within the spirit and scope of this invention.
For example, the invention is not limited to boxes, closures or shutters and may be applied to other products using a bi-stable part.
For example, the triggering means may have different shapes or constructions, only its principles being illustrated herein.
Typically, the material used for the objects and boxes of the present invention comprise any plastic material including metals, synthetic or bio-based matter, hybrid inorganic filled systems or composites.

Claims

An object comprising a least a part having at least a bi-stable behaviour in which said part is able to reach a first configuration or a second configuration, said first and second configurations being different from each other, wherein said object comprises triggering means to induce a change from one of said configurations to the other of said configurations.
The object as defined in claim 1, wherein said triggering means are linked to said part having a bi-stable behaviour and/or are linked to another part of said object.
The object as defined in one of the preceding claims, wherein said triggering means is integrated into said object or added to said object.
The object as defined in one of the preceding claims, wherein said object comprises a closure, shutter or locking mechanism having a body and a part having a bi-stable behaviour forming said mechanism, wherein one of said configurations of the mechanism is a concave-shaped configuration and the other configuration of the mechanism is a convex-shaped configuration.
The object as defined in one of the preceding claims, wherein said object is a box or container having a body and lid and said part having a bi-stable behaviour forms said lid, wherein one of said configurations of the lid is a concave-shaped configuration and the other configuration of the lid is a convex-shaped configuration.
The object as defined in the preceding claim, wherein said lid is articulated or hinged on said body.
The object as defined in one of claims 4 or 5, wherein said triggering means comprise a raised part.
The object as defined in the preceding claim, wherein said raised part is on the body and/or on the lid.
The object as defined in one of the preceding claims, wherein said configurations are stable configurations.
The object as defined in one of the preceding claims, wherein said part having a bi-stable behaviour is made of a synthetic or bio-based plastic material.
The object as defined in one of the preceding claims, wherein said object is made of a single part.