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Double-walled acrylic door for refrigerated cabinets.

Field of the invention

The present invention relates to double-walled acrylic doors which are used refrigerated cabinets of supermarkets. It relates above all to (daily) covering of so called multi-deck refrigerated cabinets.

Prior art

Various doors have been designed for use in refrigerated cabinets, both single and double-glazed. Doors are also known which are formed from two layers of plastic, wherein one layer is thermoformed in specific moulds. However, due to the thermoforming, these doors nearly always produce a disturbing visual distortion due to the inconsistent thickness of one or both plastic layers. In the past, multi-layer plastic doors have also been designed, but these have the disadvantage that they very quickly become warped due to, inter alia, temperature variations.

The Japanese patent publication JP-2000- 105065 discloses a refrigerated compartment with two doors, wherein one door comprises two transparent plastic walls. The walls are kept apart from one another at a predefined distance by means of a insert.

German patent application DE 84 16 237 Ul discloses a deep freezer which is provided with a door with three parallel-positioned, transparent walls. The three walls are arranged slidably in relation to one another by means of inserts and are held together by an external profile to absorb expansion or contraction of the walls. The material of the inserts is not specified in detail, but it is nevertheless disclosed that they are permanently joined to the middle wall and are only in sliding contact with the outer walls.

Summary of the invention

The present invention seeks to find an improved solution for the covering of multi-deck refrigerated cabinets.

According to the present invention, a door is provided for a refrigerated cabinet, wherein the door is double-walled with two transparent walls. The two transparent walls are made from flat plastic panels, and the door comprises one or more inserts , ^ , , ^ -

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which are positioned on the circumference of the two transparent walls and hold the two transparent walls parallel to one another at a predefined distance from one another, wherein the two transparent walls are flat acrylic panels and the two transparent walls and the one or more inserts are joined to one another with an elastic joining material. In this way, a simple and economical design and assembly of the door is possible, wherein a good insulation value is also obtained and a minimal visual distortion occurs.

Distortion due to unequal temperatures on either side of the door during use is effectively prevented by the elastic joining material. Further embodiments are described in the attached claims, and in the description of the figures below.

In a further aspect, the present invention relates to a method for producing a door for a refrigerated cabinet, wherein the door is double-walled with two transparent walls. The method comprises the provision of two flat plastic panels with predefined dimensions, provision of one or more inserts, positioning, screwing and bonding of one or more inserts on the circumference of the two flat plastic panels, wherein the two flat plastic panels form the two transparent walls of the door which stand parallel to one another at distance predefined by the one or more inserts. A door for a refrigerated cabinet can be produced simply and economically in this way.

In another further aspect, the present invention relates to a refrigerated cabinet for displaying sales items, comprising a frame structure and one or more doors positioned rotatably in the frame structure according to one of the present embodiments.

Brief description of the drawings

The present invention will now be discussed in greater detail with reference to the attached figures, in which:

Fig. 1 shows a three-dimensional view of the components of a door according to an embodiment according to the present invention;

Fig. 2 shows a three-dimensional view of a insert which is used in an

embodiment according to the present invention;

Fig. 3 shows a three-dimensional view of a mounting insert which is used in an embodiment according to the present invention;

Fig. 4 shows a cross-section view of two walls and a insert for mounting a door according to a further embodiment of the present invention; and

Fig. 5 shows a cross-section view of two walls and a insert for mounting a door , ,

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according to another further embodiment of the present invention.

Detailed description of example embodiments

The present invention, referred to below as a "door", is especially suitable for the covering of multi-deck refrigerated cabinets (for example chests) of the type increasingly used in supermarkets for the sake of a higher energy saving. One aspect of the present invention is a refrigerated cabinet for displaying sales items or products, which comprises a frame structure and one or more doors 1 positioned rotatably in the frame structure according to one of the embodiments described below.

The door 1 will be produced in various lengths, widths and cavity dimensions, wherein, however, the design will be the same for all embodiments. The door 1 has a height of, for example, more than 150 cm, for example 187 cm.

The door will consist of a number of components as described below, and shown in the attached figures. Fig. 1 shows a simple assembly drawing of a complete, not yet assembled door 1. The door 1 is double-walled with two transparent walls 2, which are made from flat plastic panels, with a thickness t. The door 1 comprises one or more inserts (or spacers) 3, 4 which are positioned on the circumference of the two transparent walls 2 and hold the two transparent walls 2 parallel to one another at a predefined distance d from one another. This creates a cavity space which provides additional thermal insulation and rigidity of the door 1.

In one embodiment, the double-walled door 1 is made from two flat, clearly transparent acrylic panels 2 which are joined to one another all round via acrylic inserts 3, 4, and in this way form a closed inner space 5 or box. In one embodiment, the flat plastic panels 2 are acrylic panels with a thickness t of 2-5 mm, for example 3 mm or 4 mm.

In this application, acrylic is understood to mean a transparent plastic which is also known as polymethyl methacrylate (PMMA) or other (trade) name, and can be manufactured and processed in different ways, for example to produce optically transparent flat panels.

The one or more inserts 3, 4 may therefore be transparent. In one embodiment, the two transparent walls 2 and the one or more of inserts 3 4 are bonded with an optically transparent material.

Compared with single-glazed doors, this design has a much better insulation -

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value and much less of a problem with condensation. Condensation can be a major problem, particularly with high temperature and humidity. Condensation on the doors is unacceptable because customers can then no longer clearly see the displayed products.

The advantage of the products described here in comparison with a double-glazed door lies primarily in the weight and manipulability. A double-walled acrylic door 1 is approximately half as light as a comparable double-walled glass door. The safety of acrylic compared with glass is also a major advantage.

In a further embodiment, the inserts 3, 4 are made from a material other than acrylic, such as a composite material, a carbon-fibre-based material, an aluminium- based material, or a combination thereof. These materials are also lightweight, as a result of which the total weight of the door 1 remains manipulable. In one example, the (horizontal) inserts 4 are made from aluminium, and the (vertical) inserts 3 from carbon fibre (carbon), i.e. the inserts 3, 4 are made from a combination of carbon fibre and aluminium. The inserts 3, 4 can be joined to one another at the corners with joining techniques known per se, such as e.g. screwing.

For the joint between the transparent walls 2 and the inserts 3, 4, a joining technique, existing as such, is applied with an elastic joining material such as flexible glue or flexible double-sided tape (for example acrylic tape). This last material is, for example, sufficiently viscous to be able to be supplied and processed in a roll (as a type of tape). Application of this material to the front and rear side of the inserts 3, 4 or onto the transparent walls 2 is then sufficient to form the complete door 1 by applying pressure to it. An additional advantage (but of primary importance) is that an acrylic material of this type also allows some further movement (in the region of 1 -2 mm) following assembly of the door 1 , which prevents the door 1 from warping with variations in temperature. During operational use of the door, a substantial temperature difference exists between the refrigerated area enclosed by the door 1 (+2°C) and the shop area (+25°C). Since the inserts 3, 4 are joined to one another and form a rigid frame, it is possible that the transparent walls 2 can still move independently from one another to some extent on the front and rear side (also due to the use of acrylic tape material), as a result of which the door 1 always remains straight.

A ventilation hole is disposed in the door 1 , preferably at a place not visible to the public, such as on the edges of the transparent walls 2, or in one of the inserts 3, 4. This enables some movement of the transparent walls in relation to one another (the door , ^ , ^ -

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can breathe) and, if the transparent walls 2 are made from acrylic, this ensures a sufficient moisture-regulating effect to limit or even prevent misting up of the transparent walls on the inside of the door 1.

The door 1 is designed in such a way that an optimally transparent door 1 is produced which causes a minimal visual distortion of the products behind the door 1. This design also ensures that a rigid, easily produced product is created. In order to avoid scratches on the surface insofar as possible, the door 1 is provided with an anti- scratch coating on one or both sides (for example on the outside of one of the transparent walls 2).

In a further embodiment, the flat plastic panels are coated with an anti-reflective layer. The door 1 will then be less reflective (for example on the front side). In a shop environment, the result will be a better view through to the products in a refrigerated cabinet with doors 1 according to the present invention.

In another further embodiment, one or both transparent walls 2 are coated with a heat- reflecting layer (for example an infrared-radiation-reflecting layer), as a result of which the insulation of the door 1 as a whole can be improved. An even greater energy saving can hereby be achieved in the use of refrigerated cabinets. The heat-reflecting coating is preferably applied to the inside of the door 1 , i.e. on the sides facing one another of the two transparent walls 2.

In one embodiment, the space 5 between the two flat panels 2, the so-called cavity, is filled with dry atmospheric air. In one embodiment, the one or more inserts 3, 4 are profiles which can be simply and economically produced and made to measure (for example with extrusion), in all kinds of materials. One or more inserts 3, 4 are mounting inserts 4 which are provided with a mounting recess 43 for mounting a hinge. In the embodiment shown, these are the inserts on the upper and lower edge of the door 1.

Fig. 2 shows a simple diagram of an (extruded) insert 3 for the side edges of the embodiment shown in Fig. 1. The thickness d of a main body 31 of the insert 3 also determines the distance between the two flat acrylic panels 2 of the door 1. In addition, the insert 3 comprises an edge 32 which serves as a finish around the door 1. In the example shown, the edge 32 is rounded and projects a defined distance from the main body, for example corresponding to the thickness t of the transparent walls 2.

Fig. 3 shows a simple diagram of the mounting insert 4, wherein, in this , ^ , ^ -

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embodiment, an integrated adaptation (mounting recess 43) is made for mounting an uppermost or lowermost hinge for the door 1. The inserts 3, 4 also determine the distance d between the two flat acrylic panels 2 from which the door 1 is constructed. This distance d, the so-called cavity dimension, is dependent on the specific application, and is, for example, between 10 mm and 20 mm. In one embodiment, the mounting inserts 4 are injection moulding pieces, which can be manufactured simply and economically in large quantities.

The mounting insert 4 is provided with a main body 41 , which, just as the main body 31 of the insert 3, has a thickness d, and with an edge 42 which, for example, just as the edge 32 of the insert 3, is rounded and projects outside the main body 41. In addition, in this embodiment, the mounting insert 4 is provided with a projection 44 which, in the assembled form of the door 1 , adjoins the insert 3. As an alternative, the inserts 3, 4 are formed in a T-profile.

In the embodiment shown in Fig. 1 , the mounting inserts 4 are two acrylic injection moulding pieces with an integrated fixing 43 for the hinges associated with a door 1. These two injection moulding pieces 4 form the upper and lower side of the door 1 and are made in one operation. The two injection moulding pieces 4 are bonded to the upper and lower side of the door between the aforementioned flat acrylic panels 2. The length of the injection moulding pieces 4 is dependent on the width of the required door 1.

Two acrylic extruded profiles, as inserts 3, form the two side edges of the door 1. The profile 3 is bonded between the aforementioned flat acrylic panels 2 and adjoins the aforementioned acrylic injection moulding pieces 4 on the upper and lower side. The length of the side profiles 3 is dependent on the height of the required door 1.

In a further embodiment, the door further comprises a handle (not shown). This handle can be mounted on one of the transparent walls 2 or on one of the inserts 3 on the sides of the door 1.

In a further aspect, the present invention also relates to a method for producing a door 1 for a refrigerated cabinet, wherein the door 1 is double-walled with two transparent walls 2. Two flat plastic panels are produced with predefined dimensions, just as one or more inserts 3, 4. The one or more inserts 3, 4 are positioned and bonded on the circumference of the two flat plastic panels with an elastic joining material. The two flat plastic panels then form the two transparent walls 2 of the door 1 which stand , ^ , , , , ·..^ -

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parallel to one another at a distance d predefined by the one or more inserts 3, 4. In one embodiment, the one or more inserts 3, 4 are mounting inserts 4 which are provided with a mounting recess 43, and the method further comprises the mounting of a hinge or hinge part in the mounting recess 43.

In a further embodiment, the present invention also relates to a method for producing a door 1 for a refrigerated cabinet, wherein the door 1 is double-walled with two transparent walls 2. Two flat plastic panels, provided on one side with an anti- scratch coating, are produced with predefined dimensions, just as one or more inserts 3, 4. The T-shaped inserts 3, 4 are positioned and screwed to one another to form a rigid frame. The two flat plastic panels are fitted onto the frame by means of a flexible joining technique, glue or tape. The two flat plastic panels then form the two transparent walls 2 of the door 1 which stand parallel to one another at a distance d predefined by the one or more inserts 3, 4. In this embodiment, the mounting inserts 4 have facilities for mounting adapters for externally assembled hinges. The method furthermore comprises the mounting of the hinge adapters.

Fig. 4 shows, in a cross-section view, how the joint between the two transparent walls 2 and the inserts 3, 4 can be implemented. The insert 3, 4 is provided on two sides with two projecting legs 33, 34, with a groove 36 lying between them, wherein one or both of the projecting legs 33, 34 are provided with an edge 35. Each of the two transparent walls 2 is provided with a groove in each case interworking with the edge 35. The two projecting legs 33, 34 enclose the end of one of the two transparent walls 2 following assembly. As a result, the glue joint present between the walls 2 and the inserts 3, 4 is subjected to less stress. The inserts 3, 4 are designed in such a way that a self- locking joint is created in combination with the groove 12 in the flat panels 2. For assembly of the door 1 , the inserts 3, 4 are pressed with force over the outer edges of the two flat panels 2 and snap firmly into place through the groove 12 in the inserts 3, 4 (snap-on profile). The inserts 3 or vertical profiles are extruded and the mounting inserts 4 (or uppermost and lowermost insert 4 (see the corresponding design of the embodiment shown in Fig. 1) are injection-moulded. In order to ensure that a completely airtight door 1 is produced, the end of the flat panels 2 is bonded by means of a flexible glue into the grooves 36 of the insert 3, 4. The same applies to the joints between the mounting inserts 4 (upper and lower inserts) and the inserts 3 (vertical inserts). _^ -

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Fig. 5 shows a variant of the embodiment from Fig. 4 for the joint between the inserts 3, 4 and the walls 2. In this embodiment, the door 1 comprises inserts 3, 4 which enclose the transparent walls 2 on the edges. For this purpose, the inserts are in turn provided with two projecting legs 33, 34, with a groove 36 located between them. In this embodiment, each insert 3, 4 has a small recess 37 for each wall 2 on the end of the groove 36 into which the transparent walls 2 slide. The ends of the transparent walls 2 are treated with a liquid which causes the material of the transparent walls to expand. The wall 2 is then slid into the groove 36 of the insert 3, 4, after which the liquid ensures that the end of the wall 2 expands in the area of the recess 37 in the insert 3, 4. When the expansion of this end is completed, a strong and airtight joint is produced. The inserts 3 (vertical profiles) are in turn extruded and the mounting inserts 4 (upper and lower inserts) are injection-moulded.

The present invention has been described above on the basis of a number of embodiments, with reference to the drawings. It will be clear that (functional) alternatives exist for various elements and that even more example embodiments are possible. All of these variants and modifications are deemed to fall within the scope of protection defined by the attached claims.