WO2024213751A1

WO2024213751A1 - Mattress assembly and method of adjusting a mattress assembly

Info

Publication number: WO2024213751A1
Application number: PCT/EP2024/060053
Authority: WO
Inventors: Majid Kardeh; Rose Rogin GILBERT; Manuel Mueller
Original assignee: Emma Sleep GmbH
Current assignee: Emma Sleep GmbH
Priority date: 2023-04-12
Filing date: 2024-04-12
Publication date: 2024-10-17
Anticipated expiration: 2025-10-12

Abstract

The invention relates to a mattress assembly (10) comprising a spring core assembly (12) with at least one spring pocket (28) that has a bottom fabric (30), a top fabric (32) and at least one spring coil (34) located between the bottom fabric (30) and the top fabric (32), wherein a grammage of the bottom fabric (30) is different to a grammage of the top fabric (32), a first additional layer (14), and at least one second additional layer (15) made by foam. The mattress assembly (10) is a stack assembly, wherein the spring core assembly (12) is a bottom layer of the mattress assembly (10), wherein the at least one second additional layer (15) is placed on top of the spring core assembly (12) and wherein the first additional layer (14) is a top layer.

Description

Mattress assembly and method of adjusting a mattress assembly

The invention relates to a mattress assembly and a method of adjusting a mattress assembly.

In the state of the art, mattress assemblies with different layers are known which provide a desired comfort for a user of the mattress assembly.

Mattress assemblies are known in the state of the art that only comprise foam layers, wherein at least one of the foam layers provides different lying zones, also called body zones, e.g. by means of cutouts and/or recesses. For instance, the well-known Emma One Foam Mattress is a mattress assembly that consists of foam layers.

Additionally, so-called hybrid mattress assemblies are known that also comprise a spring core layer as well as at least one foam layer located on top of the spring core layer. Usually, the spring core layer comprises several spring pockets that are manufactured in the same manner. These mattress assemblies may also have different lying zones that are established by means of the additional foam layer placed on top of the spring core layer, for instance due to cutouts and/or recesses within the foam layer. Alternatively or additionally, several foam layers are provided which also provide different lying zones, e.g. by means of cutouts and/or recesses. For instance, the Emma Hybrid Mattress comprises three foam layers and one spring core layer while providing five different lying zones.

Generally, the size and/or shape of the respective cutouts and/or recesses may be varied in order to establish the different zones, e.g. zones with different hardness or rather stiffness.

Actually, the concept of providing the different lying/body zones is used since the foam layers can be manufactured in a cost-efficient manner such that it is less cost-intensive to provide foam layers having different characteristics.

However, providing cutouts and/or recesses may result in cutoffs or rather waste of material, which is disadvantageous. To overcome this disadvantage, it is already known to provide corresponding foam layers from a foam block, thereby reducing the cutoffs or rather waste of material. This concept is described in DE 102017 117 556 A1.

However, there is still a need for an improved mattress assembly that reduces the waste of material. Similarly, there is also still a need for reducing the weight of the mattress assembly while maintaining the user experience, namely the lying comfort.

The invention provides a mattress assembly comprising a spring core assembly with at least one spring pocket that has a bottom fabric, a top fabric and at least one spring coil located between the bottom fabric and the top fabric, wherein a grammage of the bottom fabric is different to a grammage of the top fabric. The mattress assembly further comprises a first additional layer and at least one second additional layer which is made of foam. The mattress assembly is a stack assembly, wherein the spring core assembly is a bottom layer of the mattress assembly, wherein the at least one second additional layer is placed on top of the spring core assembly and wherein the first additional layer is a top layer. Therefore, the different layers and the spring core assembly are placed on top of each other to provide a stacked mattress assembly.

The invention also provides a method of adjusting a mattress assembly, particular the mattress assembly as described above. A spring core assembly of the mattress assembly is at least partially, preferably completely, surrounded by a spring core assembly envelope having a shape of a cuboid with a bottom wall, a top wall and four side walls. At least one additional layer is covered by a cover such that the at least one additional layer is disposed between the cover and the spring core assembly envelope. The spring core assembly envelope has a chain for a zip fastener configured to engage a corresponding chain of the zip fastener of the cover such that the cover together with the top wall of the spring core assembly envelope forms a chamber for the at least one additional layer. The method comprises the steps of:

Unzipping the zip fastener to obtain access to the chamber for the at least one additional layer,

Removing the at least one additional layer from the chamber, Inserting at least one new additional layer into the chamber, and

Zipping the zip fastener in order to close the chamber.

Generally, the spring core assembly and/or the first additional layer and/or the second additional layer are not fixed to each other such that they can be adjusted individually. In other words, the spring core assembly and/or the first additional layer and/or the second additional layer are independent of each other, namely loosely placed on each other (directly or indirectly) in order to establish the stack assembly. In fact, the mattress assembly can be fully customized. Thus, the spring core assembly, the first additional layer and the second additional layer are all replaceable layers of the mattress assembly. This means that the spring core assembly, the first additional layer and/or the second additional layer may be replaced by a different spring core assembly, a different first additional layer and/or a different second additional layer respectively, thereby obtaining the adjustability of the mattress assembly. Put differently, the mattress assembly can be customized to the needs and/or requirements of the customer by replacing the spring core assembly, the first additional layer and/or the second additional layer.

Accordingly, the spring core assembly that may be used as a spring core layer within the mattress assembly comprises spring pockets with different fabrics above and beneath the respective spring coils. In other words, the bottom fabric and the top fabric are located on opposite sides of the respective spring pocket(s).

Preferably, the grammage of the bottom fabric is higher than the grammage of the top fabric. Therefore, the support of the spring coils is ensured due to the higher grammage of the bottom fabric. Actually, the spring core assembly may relate to a bottom layer of the mattress assembly such that the higher grammage of the bottom fabric also ensures that the mattress assembly can be placed on a frame of a bed via the spring core assembly, namely the bottom fabric, thereby providing sufficient support and sufficient durability.

For instance, the bottom fabric and the top fabric are polypropylene (PP) fabrics, e.g. textile products that are derived from the thermoplastic polymer polypropylene. For instance, a ratio of the grammage of the top fabric to the grammage of the bottom fabric is between 0.375 and 0.8, preferably 0.4 and 0.6, particularly 0.5. This ratio ensures optimized characteristic with regard to the (mechanical) support and the mattress characteristics, e.g. hardness and/or stiffness.

Particularly, the grammage of the top fabric is between 60 g/m² and 80 g/m², for instance 65 g/m². Alternatively or additionally, the grammage of the bottom fabric is between 100 g/m² and 160 g/m², for instance 130 g/m². These specific grammages ensure that the spring coils are supported in a defined manner while simultaneously providing enough support by means of the spring core assembly due to the high grammage of the bottom fabric.

According to one aspect of the invention, the first additional layer is a cushioning layer which comprises a frame made of foam and a thermoplastic elastomer (TPE) grid layer, namely a layer having a grid structure while being made of a thermoplastic elastomer (TPE). The thermoplastic elastomer (TPE) grid layer is surrounded by a frame. In other words, the thermoplastic elastomer grid layer only makes up a partial area of the entire cushioning layer/ first additional layer. The rest of the area is provided by the frame made of foam.

For instance, the first additional layer can also be a layer made of any other material such as it can be made of foam as the at least one second additional layer having in general the same characteristics as the second additional layer.

Accordingly, the cushioning layer according to the invention ensures that the thermoplastic elastomer grid layer is substantially supported due to its material and structure as well as the frame surrendering the thermoplastic elastomer grid layer. By using a thermoplastic elastomer material instead of a gel material as well as by using the respective grid structure, the weight of the first additional layer can be reduced compared to solid layers made of a gel material.

Furthermore, the thermoplastic elastomer grid layer is essential in providing an improved breathability and reducing the amount of moisture that is retained. Therefore, using a thermoplastic elastomer grid layer in the first additional layer improves the overall user experience.

In particular, through the differing breathability of the thermoplastic elastomer grid layer and of the foam frame different cooling characteristics are obtained. In fact, the combination of the thermoplastic elastomer grid layer and the foam frame provide more cooling for the main body compared to the extremities, as the thermoplastic elastomer grid layer is associated with the main body.

In addition, the thermoplastic elastomer grid layer ensures that the entire first additional layer is foldable and/or rollable, e.g. compressible. Generally, the compressibility is obtained by the fact that the first additional layer is foldable and rollable. Consequently, the first additional layer might be compressible, foldable and rollable. Accordingly, the first additional layer can be brought into a shipping state in an easy manner, e.g. a rolled-up state, in which the thermoplastic elastomer grid layer is stored in a shipping bag.

Specifically, it is possible to fold and (afterwards) roll the entire first additional layer. This can be achieved due to the combination of the thermoplastic elastomer grid layer and the frame, particularly their respective characteristics. Consequently, the mattress is easier to transport and can be stored more efficiently.

The frame surrenders the thermoplastic elastomer grid layer while simultaneously providing sufficient support, as the frame is completely made of the foam (solid matter), whereas the thermoplastic elastomer grid layer comprises voids filled with air. Hence, the frame does not comprise voids that are introduced additionally. In other words, the frame made of foam only comprises inherent air inclusions which are associated with the foam material.

Actually, the first additional layer has two opposite main surfaces as well as four side surfaces. Each of the main surfaces are established by a respective surface of the frame and a respective surface of the thermoplastic elastomer grid layer. In contrast thereto, the side surfaces are only built by the frame, namely the foam material of the frame.

Generally, the frame and the thermoplastic elastomer grid layer are connected with each other in a permanent manner, thereby ensuring that the entire first additional layer is a single layer. For instance, the permanent connection between the frame and the thermoplastic elastomer grid layer is established by a welding and/or a chemical connection. Alternatively or additionally, when manufacturing the first additional layer, the frame is moulded to the thermoplastic elastomer (TPE) grid layer. Alternatively, the thermoplastic elastomer grid layer can be moulded to the foam of the frame when manufacturing the first additional layer. In any case, a single (prefabricated) layer is obtained, namely the first additional layer. In other words, the first additional layer is a completely independent and coherent layer, wherein the frame and the thermoplastic elastomer (TPE) grid layer are permanently fixed with each other, e.g. from the beginning. In other words, the thermoplastic elastomer (TPE) grid layer is not inserted into recess of the frame and adhered to the frame, particularly borders of the recess used for accommodating the thermoplastic elastomer (TPE) grid layer. Hence, the first additional layer may be made in one single process, namely in at least a two-component manufacturing process, for instance a two-component moulding process. Therefore, the first additional layer does not need any further layer, which supports the first additional layer and gives stability.

Accordingly, the first additional layer in form of a cushioning layer according to the invention distinguishes from assemblies that comprise a frame with a receptacle and an insert placed in the receptacle. The frame and the insert of these layers are separately formed and, if at all, connected with each other in an assembled state, but not permanently. In contrast thereto, the first additional layer according to the invention is a single layer which can be used and seen as a totally independent layer, in particular in case the first additional layer is used as an adjustable or exchangeable layer.

Moreover, the frame and the thermoplastic elastomer grid layer each have a geometric centre, wherein the geometric centres coincidence.

An aspect of the invention provides that the thermoplastic elastomer grid layer has a hardness that is higher compared to the hardness of the frame, particularly by 10% to 20%, and has a minimum netto density that is higher than the minimum netto density of the frame, particularly by a factor of 5 to 10, preferably by a factor of 6 to 8. This ratio ensures optimized characteristic with regard to the support, the handling and the cushioning, i.e. hardness and/or stiffness. Even though the thermoplastic elastomer grid layer has a higher hardness than the frame as well a higher minimum netto density than the frame, the thermoplastic elastomer grid layer provides a softer feeling to a user with regard to the lying comfort compared with the frame. This is ensured due to the structure of the thermoplastic elastomer grid layer that has the lattice structure, namely the voids filled with air, rather than a solid material.

Particularly, the thermoplastic elastomer grid layer has a minimum netto density of 230 kg/m³ and/or a hardness of 2.8 kPa. These characteristics together with the structure of the thermoplastic elastomer grid layer, namely the voids, ensure that the desired lying comfort is obtained.

Furthermore, the thermoplastic elastomer grid layer makes up between 40% and 70%, preferably 50%, of the first additional layer. That way the average area, the user would sleep on is covered by the thermoplastic elastomer grid layer, meaning the user experience is not compromised. Consequently, the size of the thermoplastic elastomer grid layer depends on the overall size of the first additional layer, which in turn depends on the mattress size. However, by not having the thermoplastic elastomer grid layer make up the whole area of the first additional layer, the handling and the lying comfort of the first additional layer can be improved.

Another aspect of the invention provides that the foam is a hypersoft foam having a minimum netto density of 32 kg/m³ and/or a hardness of 2.5 kPa. These characteristics ensure that the desired lying comfort is obtained. In contrast to the thermoplastic elastomer grid layer, the frame is made completely of the foam, namely in a solid manner. Accordingly, the minimum netto density and the hardness of the thermoplastic elastomer grid layer are higher compared to the frame due to the fact that the thermoplastic elastomer grid layer is structured differently, as it comprises the voids.

The thermoplastic elastomer grid layer has several walls intersecting each other, thereby defining voids, wherein the thermoplastic elastomer grid layer comprises equally or differently sized voids. By comprising differently sized voids, the thermoplastic elastomer grid layer can provide different lying/body zones, improving the user experience, namely by providing the preferred support for each lying/body zone, for instance for the hip, the shoulder and other body parts having different requirements. Actually, different lying/body zones with different characteristics may be provided by means of the differently sized voids. Generally, the voids, irrespective of their size, are established by the walls intersecting each other, thereby defining the voids. Furthermore, the voids allow the first additional layer to be foldable since there is room for the material of the walls to extend into when the first additional layer is folded even though the first additional layer is made by the TPE material having the characteristics outlined above.

Preferably, the thermoplastic elastomer grid layer comprises supporting areas in which the voids have a smaller size compared to voids located in other areas of the thermoplastic elastomer grid layer. This ensures optimal comfort and different support for the different body zones, leading to an improved user experience.

The voids may have different shapes, particularly rectangular shape, hexagonal shape and/or honeycomb shape. For instance, the rectangular shape relates to squares. These forms generally provide different stability which however (also) depends on the size of the voids, namely the distances of opposing walls which limit the respective voids. Furthermore, they are relatively easy to produce and therefore do not add to the production costs in a significant manner.

For instance, the first additional layer can also be a layer entirely made of foam such as the at least one second additional layer.

Another aspect provides that the mattress assembly comprises at least two second additional layers, a primary second additional layer and a secondary second additional layer, wherein each of the at least two second additional layers are made by different materials, particularly different foams. Additionally or alternatively, all second additional layers have different characteristics, particularly different minimum densities and/or a different hardness.

Generally, the hardness may be measured according to ISO 3386.

The at least two second additional layers, namely the foam layers, in the combination with the rest of mattress assembly such as the first additional layer and the spring core assembly ensure pressure relief and comfort and make the mattress assembly more durable. Generally, the second additional layers, namely the foam layers, are made without cutouts and/or recesses, e.g. as full material layers.

All the second additional layers may have the same height, e.g. 15 mm. The spring core assembly may have a height of about 200 mm, particularly 195 mm. The first additional layer, namely the cushioning layer may also have the height of one of the second additional layers, e.g. 15 mm. This means that all additional layers, regardless of their shape and/or material, have the same height of 15 mm.

Generally, the foams used for the second additional layers may relate to a comfort foam, a visco memory foam and/or a hypersoft foam.

However, for instance, the mattress core assembly may also comprise three second additional layers, namely a primary second additional layer, a secondary second additional layer and a tertiary second additional layer, which can be stacked on each other. All these second additional layers are foam layers, namely all three second additional layers.

A comfort foam is associated with the tertiary second additional layer that may be placed on the spring core assembly. For instance, the tertiary second additional layer has a minimum netto density of 30 kg/m³ and/or a hardness of 3 kPa. Alternatively, the tertiary second additional layer has a minimum netto density of 31 kg/m³ and/or a hardness of 2.8 kPa

Usually, the tertiary second additional layer has the highest hardness of all foam layers and/or the lowest minimum netto density.

The secondary second additional layer may be made by a comfort foam or rather a visco memory foam. For instance, the secondary second additional layer has a minimum netto density of 50 kg/m³ and/or a hardness of 1.8 kPa. Alternatively, the secondary second additional layer has a minimum netto density of 34 kg/m³ and/or a hardness of 2.5 kPa.

The primary second additional layer that relates to the top layer of the second additional layers may be made by a visco memory foam or rather a hypersoft foam. For instance, the primary second additional layer has a minimum netto density of 32 kg/m³ and/or a hardness of 1.5 kPa. Alternatively, the primary second additional layer has a minimum netto density of 40 kg/m³ and/or a hardness of 1.6 kPa. On top of the primary second additional layer, the first additional layer is placed.

Another aspect provides that the spring core assembly comprises a first type spring pocket and a second type spring pocket. Both types of spring pockets have the same bottom fabric and the same top fabric. The grammage of the bottom fabric is different to the grammage of the top fabric. The first type spring pocket has a first spring coil that is located between the bottom fabric and the top fabric. The second type spring pocket has a second spring coil that is located between the bottom fabric and the top fabric. The first spring coil and the second spring coil are different. For instance, the first spring coil and the second spring coil have different characteristics with regard to stiffness.

The different types of the spring pocket, namely the first type spring pocket and the second type spring pocket, ensure that different lying/body zones can be provided by the spring core assembly, causing different zones in the entire mattress assembly.

The first type spring pocket and the second type spring pocket may be neighbored and glued to each other. This ensures that the different types of spring pockets can be connected with each other even though they have different characteristics with regard to stiffness due to their different spring coils. Since the spring pockets are glued with each other, their relative positions are fixed.

The first spring coil and the second spring coil are made of steel of grade C65-C70. The first spring coil and the second spring coil are wired around a central axis and have a total of between 4.5 and 5 windings, preferably 4.75 windings.

The distance between the different windings of an uncompressed spring coil, e.g. in an unmounted state, varies along the length of the spring coil. For an uncompressed spring coil with a total height of about 250 mm, the distance between an end of the first winding of the spring coil and a plane on which the spring coil is placed is about 1.15 mm. The distance between the end of the second winding and the plane may be about 82.5 mm. The distance between the end of the third winding and the plane may be about 193 mm. The distance between the end of the forth winding and the plane may be about 243 mm. In addition, the spring coil has two opposite ends that extend downwards or upwards, namely towards the inside of the spring coil such that the ends, particularly their face sides, face each other. The distance between a lower end and the plane is about 5 mm.

Accordingly, the end portion being directly contacted with the respective fabric, e.g. top fabric or bottom fabric, may be distanced from the corresponding end, e.g. its face side.

Preferably, the diameter of the first spring coil is variable along the length of the spring coil, wherein the diameter of the first and the last winding being smaller than the diameter of the winding in the middle of the spring coil. In particular, for an uncompressed spring coil which is not in a spring pocket and has a height of between 245 mm and 255 mm, the diameter of the first winding is about 61 mm, while the diameter of the second and third winding is about 66 mm, the diameter of the fourth winding is about 58 mm and the diameter of the last incomplete winding is again about 48 mm.

The first spring coil and the second spring coil may have different wire diameters. Particularly, the wire diameter of the first spring coil is smaller than the wire diameter of the second spring coil. The different wire diameters of the spring coils provide a different hardness or rather stiffness. Therefore, different lying/body zones can be obtained that comprise either the first type spring pocket or the second type spring pocket.

The ratio of the wire diameter of the first spring coil to the wire diameter of the second spring coil may be between 0.72 and 0.95, particularly 0.9. This ratio ensures that a user may recognize a different lying/body zone, but still has a good feeling since no big differences between the respective hardness of the spring coils are provided.

For instance, the wire diameter of the first spring coil is between 1.6 mm and 1.9 mm, particularly between 1.6 mm and 1.8 mm, preferably 1.7 mm. Alternatively or additionally, the wire diameter of the second spring coil is between 1.8 mm and 2.2 mm, particularly between 1.8 mm and 2 mm, preferably 1.9 mm. These wire diameters ensure a sufficient hardness and stability of the individual spring coils while simultaneously providing the desired comfort of the lying/body zones.

A further aspect provides that several first type spring pockets are connected in series, particularly by welding, thereby forming a line of first type spring pockets. Alternatively or additionally, several second type spring pockets are connected in series, particularly by welding, thereby forming a line of second type spring pockets. Depending on the size, particularly width, of the spring core assembly, the respective line may comprise a different number of spring pockets connected with each other by welding, thereby providing the line of first type spring pockets or rather the line of second type spring pockets. Hence, the respective lines may be associated with the width of the spring coil assembly or rather the mattress assembly. Accordingly, the same type of spring pockets is used along a width dimension of the spring coil assembly or rather the mattress assembly.

Moreover, at least two lines of first type spring pockets are located next to each other, wherein the spring pockets of neighbored lines are glued to each other. Alternatively or additionally, at least two lines of second type spring pockets are located next to each other, wherein the spring pockets of neighbored lines are glued to each other. A respective zone of spring pockets of the same type may be established by providing two or more lines of the same type pocket springs. However, a certain zone may also be realized by only a single line, particularly a single line of the first type spring pockets. Zones established by the second type spring pockets may always comprise at least two lines of second type spring pockets.

Generally, adjacent lines of spring pockets, particularly irrespective of their type, may also be glued with each other, thereby establishing the spring core assembly.

The pocket springs of the adjacent lines may be glued to each other, whereas the pocket springs of the same line may be welded with each other.

Generally, the spring core assembly may be symmetrical with respect to two symmetrical lines intersecting each other in a center of the spring core assembly. Particularly, the symmetrical lines are perpendicular to each other. Thus, the spring core assembly has a symmetric design, thereby ensuring that the same spring core assembly could be used in two different directions, namely turned by 180° about its center in a plane, e.g. without flipping the spring core assembly. In other words, the spring core assembly does not have an upper edge or a lower edge since opposing edges can be interchanged. Put differently, the bottom fabric is always orientated towards the floor, e.g. the frame of a bed when used.

In general, the spring core assembly and the mattress assembly may have a length of 2 m or 1.9 m such that 33 or rather 32 lines of spring pockets are used, respectively. All of the lines may be established by the two different types of spring pockets, particularly lines of spring pockets.

In a certain embodiment, e.g. a width of 90 cm, the spring core assembly comprises 14 spring pockets per line that are welded together. However, the number of spring pockets per line depends on the width of the spring core assembly or rather the mattress assembly. Accordingly, a spring core assembly or rather a mattress assembly with a width of more than 90 cm my comprise more than 14 spring pockets per line resulting in 448 spring pockets (90 cm x 190 cm) or rather 462 spring pockets (90 cm x 200 cm). Depending on the width of the spring core assembly, a different number of spring pockets may be provided. For instance, the spring core assembly has a height of 195 mm.

A first embodiment may comprise eleven zones.

In fact, a first zone that starts from a first edge may comprise two lines of a certain type of spring pockets, for instance the second type spring pockets. A second zone adjoins the first zone, which comprises six lines of a certain type of spring pockets, for instance the first type spring pockets. A third zone adjoins the second zone, which comprises five lines of a certain type of spring pockets, for instance the second type spring pockets. A fourth zone adjoins the third zone, which only comprises one single line of a certain type of spring pockets, for instance the first type spring pockets. A fifth zone adjoins the fourth zone, which comprises two lines of a certain type of spring pockets, for instance the second type spring pockets. A sixth zone adjoins the fifth zone, which only comprises one single line of a certain type of spring pockets, for instance the first type spring pockets. A seventh zone adjoins the sixth zone, which comprises two lines of a certain type of spring pockets, for instance the second type spring pockets. An eighth zone adjoins the seventh zone, which only comprises one single line of a certain type of spring pockets, for instance the first type spring pockets. A ninth zone adjoins the eighth zone, which comprises five lines of a certain type of spring pockets, for instance the second type spring pockets. A tenth zone adjoins the ninth zone, which comprises six lines of a certain type of spring pockets, for instance the first type spring pockets. An eleventh zone adjoins the tenth zone, which comprises two lines of a certain type of spring pockets, for instance the second type spring pockets. The eleventh zone ends at a second edge that is opposite to the first edge.

A symmetrical line of the spring core assembly runs along the sixth zone, e.g. along the single line provided by the sixth zone. Another symmetrical line runs perpendicularly thereto while intersecting all zones, e.g. all lines. Both symmetrical lines intersect each other in the middle/center of the spring core assembly.

A second embodiment may comprise nine zones.

In fact, a first zone that starts from a first edge may comprise two lines of a certain type of spring pockets, for instance the second type spring pockets. A second zone adjoins the first zone, which comprises six lines of a certain type of spring pockets, for instance the first type spring pockets. A third zone adjoins the second zone, which comprises six lines of a certain type of spring pockets, for instance the second type spring pockets. A fourth zone adjoins the third zone, which only comprises one single line of a certain type of spring pockets, for instance the first type spring pockets. A fifth zone adjoins the fourth zone, which comprises two lines of a certain type of spring pockets, for instance the second type spring pockets. A sixth zone adjoins the fifth zone, which only comprises one single line of a certain type of spring pockets, for instance the first type spring pockets. A seventh zone adjoins the sixth zone, which comprises six lines of a certain type of spring pockets, for instance the second type spring pockets. An eighth zone adjoins the seventh zone, which comprises six lines of a certain type of spring pockets, for instance the first type spring pockets. A ninth zone adjoins the eighth zone, which comprises two lines of a certain type of spring pockets, for instance the second type spring pockets. The ninth zone ends at a second edge that is opposite to the first edge. A symmetrical line of the spring core assembly runs along the fifth zone, e.g. between the two lines provided by the fifth zone. Another symmetrical line runs perpendicularly thereto while intersecting all zones, e.g. all lines. Both symmetrical lines intersect each other in the middle/center of the spring core assembly.

The different zones are used to support a user differently when the user lies on the mattress assembly.

In general, the distribution of different spring coils, particularly spring coils with different diameters, ensures zoning the spring core assembly or rather the mattress assembly. The zoning refers to provide support and relief to different areas of body. In fact, different zones of the body are head, shoulder, lumbar, pelvic, thigh, calf and foot. The spring core assembly provides adequate support and comfort for people of different body types irrespective of their sleeping position.

According to another aspect of the invention, the spring core assembly is made edge-to-edge without lateral foam material such that the mattress assembly is foldable and rollable, e.g. compressible, foldable and rollable.

Particularly, the entire mattress assembly is foldable and rollable, namely compressible, foldable and rollable, such that the mattress assembly has a shipping state in which the first and the second additional layer and the spring core assembly are folded at least once and rolled up. As mentioned before, the first additional layer is foldable and rollable such that the first additional layer can be brought into the shipping state. The same applies to the at least one second additional layer. Consequently, the entire mattress assembly, comprising the first additional layer, the at least one second additional layer and the spring core assembly can be folded and rolled. Put differently, the second additional layer is placed on the first additional layer and the first additional layer is placed on the spring core assembly when the entire mattress assembly is folded and rolled up.

When a mattress assembly is in its assembled state, the spring core assembly, the first additional layer and the at least one second additional layer are loosely placed on top of each other. In other words, the first additional layer, the at least one second additional layer and the spring core assembly are not permanently fixed to each other, in particular they are not connected to each other by the means of an adhesive. This ensures that one part of the mattress assembly, e.g. the first additional layer, can be changed and/or replaced without having to change the other parts, e.g. the spring core assembly and the at least one second additional layer.

The spring core assembly may be at least partially surrounded by a spring core assembly envelope having the shape of a cuboid with a bottom wall, a top wall and four side walls. Preferably, the spring core assembly is completely surrounded by the spring core assembly envelope. This means that the spring core assembly is wrapped in the envelope. The size of the spring core assembly envelope is essentially the size of the spring core assembly itself to ensure a direct contact between the spring core assembly and the spring core assembly envelope.

The spring core assembly envelope thus forms a chamber for the spring core assembly.

The bottom wall, the top wall and the four side walls of the spring core assembly envelope are made of fabric. In particular, the bottom wall and the top wall are made of the same fabric and the side walls are made of a different fabric. Preferably, the fabric of the bottom wall and the top wall is thinner than the fabric of the side walls. The thicker and more robust and durable fabric of the side walls provides better protection against mechanical loadings of the spring core assembly, while it is sufficient to use a thinner and lighter fabric for the top and the bottom wall, as the mechanical loading on these walls is lower.

The spring core assembly envelope comprises a first zip fastener for opening and closing the spring core assembly envelope, preferably located at the edge between the bottom wall and at least one of the four side walls. This ensures that, when the spring core assembly needs to be replaced, only the spring core assembly is to be replaced while the spring core assembly envelope can be retained. In addition, the spring core assembly envelope can be cleaned, e.g. washed, which is only possible, if the spring core assembly can be removed from the spring core assembly envelope. Preferably, the first zip fastener of the spring core assembly envelope extends at least along the length of one side wall. Even more preferably, the first zip fastener extends along the lengths of one of the shorter side walls and a portion of the adjacent two longer side walls. In particular, the first zip fastener starts somewhere on an edge of a long side wall and extends along both short side walls and the entire length of a second long side wall. This allows the spring core assembly to be easily removed from the spring core assembly envelope and ensures an easy handling process. Thus, the spring core assembly envelope is completely openable in order to remove and/or adjust the spring core assembly. However, the bottom wall is at least partially permanently attached to the spring core assembly envelope.

The at least one second additional layer may be placed on top of the spring core assembly envelope such that the at least one second additional layer is separated from the spring core assembly by the top wall of the spring core assembly envelope. The first additional layer can be placed on top of the at least one second additional layer and is therefore separated from the spring core assembly by the top wall of the spring core assembly envelope and the at least one second additional layer. In other words, there is no direct contact between the at least one second additional layer and the spring core assembly.

The at least one second additional layer is covered by a cover, in particular a cover made of a fabric, such that the at least one second additional layer is disposed between the cover and the spring core assembly envelope.

The first additional layer may also be covered by the cover of the at least one second additional layer.

[ppi]Thus, the first additional layer and the second additional layer are simply stacked on top of each other, but not fixed together, e.g. glued together. The stacked additional layers are covered by a cover having the second zip fastener to connect the cover to the spring core assembly envelope and to form a common chamber for the first and the second additional layer. As the additional layers are not fixed together, this design allows the replacement of at least one of the additional layers, whereas the other one remains. In a further embodiment, the two additional layers are covered and separated for the other additional layer by a second cover having a chain of a second zip fastener such that the cover of the first additional layer can be zipped to the cover of the second additional layer, the cover of the second additional layer can be zipped to the spring core assembly envelope. In other words, the first additional layer is placed between two covers, whereas the second additional layer is placed between the cover and the spring core assembly envelope, so that each of the additional layers is in direct contact with at least one cover. The covers and/or the cover and the spring core assembly envelope form a zippable layer pocket for the additional layers.

In both embodiments, the cover is used to cover the first additional layer and/or the at least one second additional layer.

The spring core assembly envelope has a chain for a second zip fastener configured to engage a corresponding chain of a zip fastener of the cover such that the cover together with the top wall of the spring core assembly envelope forms a chamber for the at least one second additional layer. For instance, also the first additional layer can be placed in this chamber.

By connecting the cover to the spring core assembly envelope, the at least one second additional layer is secured to the spring core assembly without the need for an adhesive. Furthermore, because the attachment is made by a second zip fastener, the cover can be zipped and unzipped to the spring core assembly envelope whenever necessary, e.g. to replace the at least one second additional layer or to clean the cover. Preferably and in contrast to the bottom wall of the spring core assembly envelope, the cover can be fully removed from the spring core assembly envelope.

Generally, the second zip fastener is established by the chain of the spring core assembly envelope and the corresponding chain of the cover.

In other words, the mattress assembly comprises a spring core assembly wrapped in a spring core assembly envelope defining a first chamber for the spring core assembly and at least one second additional layer covered by a cover defining a second chamber for the at least one second additional layer. The spring core assembly and the at least one second additional layer can be completely removed from their respective chambers, the removal being independent of each other, meaning, the spring core assembly can be removed while at the same time the at least one second additional layer remains in its second chamber. In contrast, the at least one second additional layer can also be removed while the spring core assembly remains in the spring core assembly envelope.

This also allows e.g. the rotation of the at least one second additional layer in order to have a different hardness. Furthermore, in the case of double-sized mattress assemblies having two of the at least one second additional layers placed side by side, only one of the two at least one second additional layers may be rotated while the other remains in its position. Thus, the hardness of each side of a double-sized mattress assembly can be adjusted independently of the hardness of the other side of the double-sized mattress assembly.

The same applies to the first additional layer. Hence, the first additional layer covered by the cover or a second cover can be replaced, rotated or otherwise adjusted independently from the at least one second additional layer, the spring core assembly or the other side of a double-sized mattress assembly.

In other words, the spring core assembly envelope together with the cover allows for a fully customized mattress in which each layer can be replaced, removed, rotated and adjusted individually and independently.

The chain of the second zip fastener of the cover is located at the edge between the top wall and the side walls of the spring core assembly envelope and extends at least along the length of one side wall, preferably the chain of the second zip fastener extends along the circumference of the top wall.

This allows the cover to be completely removed from the spring core assembly envelope to enable e.g. to allow the cover to be cleaned separate from the spring core assembly envelope. It is also possible to replace the cover with another cover of a different height, e.g. to adapt the cover to another second additional layer having a different height.

The spring core assembly envelope and the cover form a closed outer shell of the mattress assembly which is exposed to the environment. Thus, the first additional layer and the second additional layer are covered by the cover and thus protected from external influences, and the spring core assembly is protected by the spring core assembly envelope.

Generally, the spring core assembly is associated with the bottom of the mattress assembly, e.g. the spring core assembly relates to the bottom layer, such that any bottom of a component, e.g. the bottom wall of the spring core assembly envelope or the bottom fabric of the spring pockets, faces towards the direction pointing to the bottom. Consequently, the top is opposite to the bottom.

The foregoing aspects and manner of the attended advantages of the claimed subject matter will become more readily appreciated, as the same become better understood by reference to the following description, when taken in conjunction with the accompanying drawings. In the drawings,

Figure 1 schematically shows an overview of a mattress assembly according to a first embodiment of the invention that uses a spring core assembly according to a first embodiment of the invention,

Figure 2 schematically shows an overview of a cushioning layer that may be used with any of the perceiving embodiments, wherein the cushioning layer comprises a thermoplastic elastomer grid layer and a foam frame,

Figure 3 shows examples of a thermoplastic elastomer grid layer, wherein Figure 3A shows rectangular voids and Figure 3B shows triangular voids,

Figure 4 schematically shows an overview of a mattress assembly according to a second embodiment of the invention that uses a spring core assembly according to a second embodiment of the invention,

Figure 5 schematically shows an overview of a mattress assembly according to a third embodiment of the invention that uses a spring core assembly according to a third embodiment of the invention,

Figure 6 schematically shows an overview of a mattress assembly according to a fourth embodiment of the invention that uses a spring core assembly according to a fourth embodiment of the invention, Figure 7 is a perspective view of a mattress assembly from below, which comprises a spring core assembly inside a spring core assembly envelope and a cover according to the invention,

Figure 8 is a perspective view of the mattress assembly according to Figure 7 from the top, wherein a partially unzipped cover is shown, and

Figure 9 shows a perspective side view of the mattress assembly according to the Figures 7 and 8 with the spring core assembly envelope and the cover connected by a second zip fastener.

In Figure 1, a mattress assembly 10 is shown that comprises a spring core assembly 12, a top view of which is also illustrated in Figure 1. As shown in the overview of the mattress assembly 10, the spring core assembly 12 corresponds to the bottom layer of the mattress assembly 10.

In addition, the mattress assembly 10 comprises a first additional layer 14 that corresponds to a top layer of the mattress assembly 10. The first additional layer 14 is a cushioning layer.

Between the first additional layer 14 and the spring core assembly 12, the mattress assembly 10 further comprises three second additional layers 15, namely a primary second additional layer 16, a secondary second additional layer 17 as well as a tertiary second additional layer 18 all together being a second additional layer 15.

Therefore, the mattress assembly 10 relates to a stack assembly, as different layers 12 to 18 are stacked on top of each other in order to establish the mattress assembly stack.

In contrast to the spring core assembly 12, the second additional layer 15 comprising the three second additional layers 16 to 18 are made of a foam.

The first additional layer 14, shown in Figure 2 in more detail, comprises a frame 20 made of a foam and a thermoplastic elastomer (TPE) grid layer 22. The exact size of the TPE grid layer 22 depends on the overall size of the mattress assembly 10, meaning that the foam frame 20 will be selected based on the size of the TPE grid layer 22. The TPE grid layer 22 is placed in the center of the cushioning layer 14 such that geometrical centers of the frame 20 and the TPE grid layer 22 coincidence.

This is achieved by moulding the frame 20 onto the thermoplastic elastomer grid layer (TPE) or by moulding the thermoplastic elastomer grid layer 22 onto the foam of the frame 20. Thus, the first additional layer 14 is an individual, single and inherent stabile first additional layer 14.

Actually, the center region of a user lying on top of the mattress assembly 10 is supported by the TPE grid layer 22.

This ensures that the cushioning layer 14 has different cooling characteristics.

Actually, the differing breathability of the thermoplastic elastomer grid layer 22 and of the foam frame 20 provide the different cooling characteristics. In fact, the thermoplastic elastomer grid layer 22 is associated with a main body in order to provide more cooling compare to the foam frame 20 that is associated with the extremities of a user lying on the cushioning layer 14.

In the following, example sizes and weights for standard European and British mattresses are discussed in more detail. However, the exact values are subject to change depending on which country the mattress is intended for.

For a 90 cm by 200 cm mattress, the TPE grid layer 22 has a width of 60 cm and a length of 150 cm leading to a weight of the TPE grid layer 22 of 3.2 kg.

For a 80 cm by 200 cm mattress, the TPE grid layer 22 may also have a width of 60 cm and a length of 150 cm leading to a weight of the TPE grid layer 22 of 3.2 kg.

In case of a 140 cm by 200 cm mattress, the TPE grid layer 22 has a width of 110 cm and a length of 150 cm leading to a weight of the TPE grid layer 22 of 5.9 kg.

For a 140 cm by 190 cm mattress, the TPE grid layer 22 has a width of 110 cm and a length of 140 cm leading to a weight of the TPE grid layer 22 of 5.5 kg. In case of a 160 cm by 200 cm mattress, the TPE grid layer 22 has a width of 130 cm and a length of 150 cm leading to a weight of the TPE grid layer 22 of 7.0 kg.

In case of a 180 cm by 200 cm mattress, the TPE grid layer 22 has a width of 150 cm and a length of 150 cm leading to a weight of the TPE grid layer 22 of 8.0 kg.

Depending on the size of the first additional layer 14, the thermoplastic elastomer grid layer 22 makes up between 40 % and 70 % of the first additional layer 14. Hence, the foam frame 20 has a size that corresponds to 30 % to 60 % of the first additional layer 14, which also depends on the respective size of the first additional layer 14.

As inter alia shown in Figures 3a and 3b, the TPE grid layer 22 has several walls 24 that intersect each other and, hence, define voids 26 between them. The voids 26 are free of material, e.g. filled with air. Hence, the TPE grid layer 22 has a lattice structure due to the walls 24 and the voids 26, wherein the open sides of the voids 26 face upwards. Accordingly, the TPE grid layer 22 has a continuous base 27 via which the TPE grid layer 22 his located on top of the second additional layer 15, e.g. the primary second additional layer 16. The several walls 24 may extend from the continuous base 27 in a perpendicular direction upwardly.

The voids 26 can have any shape. For instance, the voids 26 are rectangular, hexagonal and/or shaped like honeycombs. These forms provide sufficient, but different support, while providing the desired comfort for the user. Moreover, these different shapes can be realized in a cost-efficient manner.

In the shown embodiment of Figure 3b, the voids 26 have a honeycomb shape. In contrast thereto, the voids 26 of the embodiment shown in Figure 2 relate to squares. Thus, they have a rectangular shape.

Generally, the voids 26 may be equally sized as shown in Figures 2 and 3b or rather differently sized as indicated in the embodiment shown in Figure 3a.

The differently sized voids 26 may establish different supporting areas such that a harder or rather a softer support is provided. The TPE grid layer 22, namely the TPE material, has a density of at least 230 kg/m³ and/or a hardness of 2.8 kPa.

Contrarily, the hypersoft foam making up the frame 20 of the first additional layer 14, which surrenders the TPE grid layer 22, has a minimum netto density of 32 kg/m³ and/or a hardness of 2.5 kPa. However, the frame 20 is solid, whereas the TPE grid layer 22 comprises additionally introduced voids 26.

Accordingly, the thermoplastic elastomer (TPE) grid layer 22 has a hardness that is higher compared to the hardness of the frame 20, particularly by 10 % to 20 %.

Further, the thermoplastic elastomer (TPE) grid layer 22 has a minimum netto density that is higher than the minimum netto density of the frame 20, particularly by a factor of 5 to 10, preferably by a factor of 6 to 8.

In particular, the frame 20 is only defined by sidewalls, meaning the frame 20 does not have a continuous bottom.

In the shown embodiment, the first additional layer 14 and each of the three second additional layers 16 - 18 have the same height, namely 15 mm, whereas the spring core assembly 12 has a height of 195 mm or 200 mm, resulting in an overall height of 255 mm or 260 mm.

As discussed above, the three second additional layers 16 - 18 are made of a foam, particularly different foams. Accordingly, the respective characteristics of the three second additional layers 16 - 18 may differ.

For instance, the primary second additional layer 16 relates to the top part of the second layer 15 and is made of a hypersoft foam having a minimum netto density of 32 kg/m³ and a hardness of 1.5 kPa.

The secondary second additional layer 17 may be made by a visco-memory foam having a minimum netto density of 50 kg/m³ and a hardness of 1.8 kPa.

The tertiary additional layer 18 and may be made by a comfort foam, e.g. a Pll foam having a minimum netto density of 30 kg/m³ and a hardness of 3 kPa.

Thus, the primary second additional layer 16 is in direct or indirect contact with the first additional layer 14, the secondary second additional layer 17 is disposed between the primary second additional layer 16 and the tertiary second additional layer 18, while the tertiary second additional layer 18 is in direct or indirect contact with the spring core assembly 12.

Generally, the first additional layer 14 and the at least one second additional layer 15 are loosely stacked on top of each other such that they are not attached to each other and can be individually replaced.

The spring core assembly 12 comprises several spring pockets 28 that are schematically shown in Figure 1. The spring pockets 28 each comprise a bottom fabric 30 as well as a top fabric 32 via which the spring pockets 28 are in contact with the tertiary second additional layer 18.

Each spring pocket 28 has a spring coil 34 that is located between the bottom fabric 30 and the top fabric 32. The spring coils 34 are made of a metal wire.

The respective fabrics, namely the bottom fabric 30 and the top fabric 32, have different grammages. For instance, the grammage of the bottom fabric 30 is higher than the grammage of the top fabric 32. The several spring pockets 28 may have their own bottom fabric 30 and/or top fabric 32. Alternatively, the several spring pockets 28 may share a common bottom fabric 30 and/or a common top fabric 32.

For instance, a ratio of the grammage of the top fabric 32 to the grammage of the bottom fabric 30 is between 0.4 to 0.6, particularly 0.5.

Specifically, the grammage of the top fabric 32 may be between 60 g/m³ and 80 g/m³, particularly 65 g/m³, whereas the grammage of the bottom fabric 30 is between 100 g/m³ and 160 g/m³, particularly 138 g/m³.

In fact, the bottom fabric 30 provides a support surface of the entire mattress assembly 10 as shown in Figure 1.

Therefore, these different grammages of the fabrics 30, 32 ensure proper support of the spring coils 34 located within the spring pockets 28 as well as proper support for a user of the entire mattress assembly 10. For instance, the bottom fabric 30 and the top fabric 34 are made by polypropylene (PP) fabrics, e.g. textile products that are derived from the thermoplastic polymer polypropylene.

A top view on the spring core assembly 12 is shown in Figure 1 as well to which reference is made hereinafter.

The top view illustrates that the spring core assembly 12 is established by two different types of spring pockets 28, namely a first type spring pocket 36 as well as a second type spring pocket 38.

The different type spring pockets 36, 38 distinguish from each other by their respective spring coils 34, particularly the wire diameter of the respective spring coils 34.

In fact, the first type spring pocket 36 has a first spring coil 42 with a wire diameter between 1.6 mm and 1.9 mm, particularly 1.7 mm, whereas the wire diameter of the second spring coil 42 is between 1.8 mm and 2.2 mm, particularly 1.9 mm.

For instance, the ratio of the wire diameter of the first spring coil 40 to the wire diameter of the second spring coil 42 is between 0.72 and 0.95, particularly 0.9.

In the shown embodiment, the spring core assembly 12 comprises several different zones A-l, namely nine different zones in total. The zones are established by areas defined by the different types of spring pockets 28.

Each zone A-l comprises only one type of spring pocket 28, namely either the first type spring pocket 36 or the second type spring pocket 38.

The nine different zones each comprise at least one line of the certain type of spring pockets 28.

Generally, a line of a specific type of spring pockets 28 means that the respective spring pockets 28 are made of the same type and interconnected with each other by welding. The line of spring pockets 28 has a length that corresponds to the width W of the spring core assembly 12 or rather the mattress assembly 10. In the shown embodiment, one line comprises fourteen spring pockets 28, irrespective of the specific type of spring pocket 28.

In fact, the first zone A comprises two lines of the second type spring pockets 38. The adjacent second zone B comprises six lines of the first type spring pockets 36. The third zone C comprises six lines of the first type spring pockets 38. The fourth zone D comprises one single line of the first type spring pocket 36. The fifth zone E comprises two lines of the second type spring pockets 38. The sixth zone F comprises one single line of the first type spring pockets 36. The seventh zone G comprises six lines of the second type spring pockets 38. The eighth zone H comprises six lines of the first type spring pockets. Finally, the ninth zone I comprises two lines of the second type spring pockets 38.

In the shown embodiment, the spring core assembly 12 has a length L of 190 cm. Therefore, the spring core assembly 12 comprises 40 lines wherein these 40 lines are interconnected with each other by gluing.

As indicated above, the respective spring pockets 28 of one line, particularly their respective spring coils 34, are interconnected with each other by welding, thereby establishing the line.

In contrast thereto, the spring pockets 28 of adjacent lines are connected with each other by gluing.

Generally, the spring pockets 28, particularly their spring coils 34, are welded to each along a first dimension, e.g. the width W.

Moreover, the spring pockets 28 are glued to each along a second dimension, e.g. the length L, which is perpendicular to the first dimension, e.g. the width W.

Further, the spring core assembly 12 is symmetrical with respect to two lines of symmetry S1 and S2 which intersect each other in the center or middle M of the spring core assembly 12.

In fact, the second symmetric axis S2 runs through the fifth zone E, particularly between both lines of the fifth zone E, namely between the sixteenth and seventeenth line of spring pockets 28 of the entire spring core assembly 12 along its length L. The second symmetry axis S2 intersects the first symmetry axis S1 within the fifth zone E, namely between the seventh and eighth column of spring pockets 28 along the width W.

In Figure 4, a similar embodiment is shown that distinguishes from the first embodiment in that the length L of the spring core assembly 12 and the mattress assembly 10 is increased to 2 m. Therefore, the spring core assembly 12 comprises one additional line, namely 33 in total.

This additional line causes a different distribution of the zones, as eleven zones A-K are provided.

Again, the different zones A-K are established by the lines of spring pockets 28, wherein each line comprises fourteen spring pockets 28 in the shown embodiment.

Moreover, the different zones may be established by two different types of spring pockets 28, namely either the first spring pocket 36 or the second type spring pocket 38.

The first zone A comprises two lines of the second type spring pocket 38. The adjacent second zone B comprises six lines of the first type spring pocket 36. The adjacent third zone C comprises five lines. The adjacent fourth zone D comprises one single line of the first type spring pocket 36. The adjacent fifth zone E comprises two lines of the second type spring pocket 38. The adjacent sixth zone F comprises one single line of the first type spring pocket 36.

The sixth zone F also comprises the second symmetry axis S2 that runs through the single line and intersects with the first symmetry access in the middle M.

The adjacent seventh zone G comprises two lines of the second type spring pocket 38. The adjacent eighth zone H comprises only one line of the first type spring pocket 36. The adjacent ninth zone I comprises five lines of the second type spring pocket 38. The adjacent tenth zone J comprises six lines of the first type spring pocket 36. Finally, the adjacent eleventh zone K comprises two lines of the second type spring pocket 38. The first additional, layer 14 and the three second additional layers 16 - 18 are similar to the ones of the first embodiment shown in Figure 1 and, thus, reference is made thereto.

In Figure 5, a third embodiment is shown that shows a mattress assembly 10 and a spring core assembly 12 having a length of 190 cm. The size is similar to the one of the first embodiment shown in Figure 1.

Actually, the spring core assembly 12 also comprises 40 lines of spring pockets 28. In fact, the distribution of the different types of spring pockets 28, namely the first type spring pockets 36 and the second type spring pockets 38, is similar to the one shown in Figure 1. Therefore, reference is made to the explanations given above.

However, the mattress assembly 10 differs from the one shown in the first embodiment, as the three second additional layers 16 - 18 are made differently.

Generally, the three second additional layers 16, 18 each have a height of 15 mm similar to the first embodiment.

However, the characteristics of the three second additional layers 16 - 18 differ from the ones of the first embodiment, e.g. due to different materials used for the three second additional layers 16, 18.

In fact, the third additional layer 18 is made of a visco-memory foam that has a minimum netto density of 40 kg/m³ and a hardness of 1.6 kPa. The second additional layer 17 is made of a comfort foam that has a minimum netto density of 42 kg/m³ and a hardness of 2.5 kPa.

Therefore, the same spring core assembly 12 is used which however is used in connection with a different additional layer structure, thereby providing a mattress assembly 10 with different characteristics.

In Figure 6, a fourth embodiment is shown that is a combination of the second embodiment shown in Figure 4 and the third embodiment shown in Figure 5, as the mattress assembly 10 and the spring core assembly 12 also have a length of 2 m like the second embodiment, but the mattress assembly 10 comprises the same three second additional layers 16 - 18 used in the third embodiment. Accordingly, the spring core assembly 12 of the fourth embodiment also comprises 33 lines as already discussed with respect to the second embodiment shown in Figure 4, but the three second additional layers 16 to 18 discussed with respect to the third embodiment shown in Figure 5.

Therefore, reference is made to the explanations given above with regard to the second and third embodiments.

Generally, the first additional layer 14 is compressible, foldable and rollable, such that the first additional layer 14 can be brought into a shipping state. The shipping state of the first additional layer 14 is obtained by folding the first additional layer 14 at least once, for instance along an axis being perpendicular to the longer side of the first additional layer 14, and afterwards rolling up the first additional layer 14, namely the first additional layer 14 folded at least once. Thus, a compact size of the first additional layer 14 is achieved such that the first additional layer 14 can be put into a shipping bag.

Particularly, the entire mattress assembly 10 is also compressible, foldable and rollable such that the entire mattress assembly 10, comprising the spring core assembly 12, the first additional layer 14 and the at least one second additional layer 15, can be brought into a shipping state. This is upon others achieved by a spring core assembly made edge-to-edge without lateral foam material.

Thus, a compact size of the entire mattress assembly 10 is achieved such that the entire mattress assembly 10 can be put into a shipping bag.

Figure 7 shows a perspective view of the mattress assembly 12 from below. As it can be seen, the spring core assembly 12 of the mattress assembly 10 is disposed within a spring core assembly envelope 40. The spring core assembly envelope 40 has the shape of a cuboid with a bottom wall 42, a top wall 44 (see Figure 8) and four side walls 46. The spring core assembly envelope 40 thus forms a first closed chamber for the spring core assembly 12 and completely surrounds the spring core assembly 12.

The spring core assembly envelope 40 is made of fabric, wherein the bottom wall 42 and the top wall 44 being made of the same fabric and the side walls 46 being made of a different fabric. The fabric of the bottom wall 42 and the top wall 44 is thinner and less robust than the fabric of the four side walls 46. This is mainly because the spring core assembly envelope 40 forms the “outer shell” of the spring core assembly 12 which is in direct contact with e.g. the bed frame. As the side walls 46 are exposed to greater mechanical loads, they must be made of a fabric which is more robust than the fabric of the bottom wall 42 and the top wall 44.

The spring core assembly envelope 40 comprises a first zip fastener 48 for opening and closing the spring core assembly envelope 40.

The first zip fastener 48 is preferably located at an edge 50 between the bottom wall 42 and at least one of the four side walls 46.

Thus, the bottom wall 42 of the spring core assembly envelope 40 can be zipped and unzipped to the side walls 46 of the spring core assembly envelope 40 to provide access to the spring core assembly 12 e.g. when the spring core assembly 12 needs to be replaced with another.

The first zip fastener 48 extends at least along the length of one side wall 46, preferably it extends along the length of one side wall 46 and in part also along the length of the adjacent side walls 46.

Particularly, the first zip fastener 48 starts somewhere on the edge 50 of a long side wall 44 and extends over the portion of the long side wall 44, a short side wall 44, the second long side wall 44 and the entire second short side wall 44 and ends at an edge between two side walls 44. Thus, the first zip fastener 48 extends along both short side walls 44, the entire length of one long side wall 44 and at least 1/3 of the second long side wall 44. In other words, the bottom wall 42 of the spring core assembly envelope 40 cannot be completely removed from the spring core assembly envelope 40.

As it can be seen in Figure 8, the at least one second additional layer 15 is placed on top of the top wall 46 of the spring core assembly envelope 40. Thus, there is no direct contact between the spring core assembly 12 and the second additional layer 15 as they are separated from each other by the top wall 46 of the spring core assembly envelope 40. The at least one second additional layer 15 may be covered by a cover 52 extending over the entire top side of the second additional layer 15 as well as over the side walls, as also shown in Figure 9.

The cover 52 is made of fabric such that the at least one second additional layer 15 is disposed between the cover 52 and the spring core assembly envelope 40.

It is of course also possible to place the first additional layer 14 on top of the second additional layer 15 in order to cover both layers 14, 15 with the cover 52.

The cover 52 may be fixed and secured to the spring core assembly envelope 40 by a second zip fastener 54. The second zip fastener 54 comprises a chain 56 which is attached to the spring core assembly envelope 40 and a second chain 58 attached to the cover 50. The two chains 56, 58 can be interlocked so that the cover 52 can be reversibly fixed to the spring core assembly envelope 40. Thereby, the cover 52 together with the spring core assembly envelope 40, preferably with the top wall 46 of the spring core assembly envelope 40 form a second chamber for the at least one second additional layer 15 and optionally also for the first additional layer 14.

The chain 58 of the second zip fastener 54 of the cover 52 is located at an edge 60 between the top wall 44 and the side wall 46 of the spring core assembly envelope 40. The chain 58 thereby extends along the circumference of the top wall 44 such that the cover 52 can be completely removed from the spring core assembly envelope 40.

In an assembled state, the spring core assembly envelope 40 and the cover 52 are zipped together, enclose the entire spring core assembly 12, the first and second additional layers 14, 15 and form an outer shell of the mattress assembly 10.

However, if required, the spring core assembly 12 and/or the first additional layer 14 and/or the at least one second additional layer 15 may be removed from the corresponding chamber in order to rotate, replace or change the desired layer 12, 14, 15 independently of the other layers 12, 14, 15. Generally, at least two separately formed chambers are provided by the spring core assembly envelope 40 and the cover 52 zipped together. The at least two separately formed chambers encompass the entire spring core assembly 12 and the remaining layers, respectively. The remaining layers relate to the first and second additional layers 14, 15. The second additional layer 15 may comprise sub-layers, e.g. a primary second additional layer, a secondary second additional layer and a tertiary second additional layer.

The respective layers, particularly the sub-layers, may be placed on top each other (directly) in a loosely manner or rather glued together, thereby forming a package.

Claims

1. A mattress assembly (10) comprising a spring core assembly (12) with at least one spring pocket (28) that has a bottom fabric (30), a top fabric (32) and at least one spring coil (34) located between the bottom fabric (30) and the top fabric (32), wherein a grammage of the bottom fabric (30) is different to a grammage of the top fabric (32), a first additional layer (14), and at least one second additional layer (15) made by foam, wherein the mattress assembly (10) is a stack assembly, wherein the spring core assembly (12) is a bottom layer of the mattress assembly (10), wherein the at least one second additional layer (15) is placed on top of the spring core assembly (12) and wherein the first additional layer (14) is a top layer.

2. The mattress assembly (10) according to claim 1, wherein the first additional layer (14) is a cushioning layer which comprises a frame (20) made of a foam and a thermoplastic elastomer (TPE) grid layer (22), wherein the thermoplastic elastomer grid layer (22) is surrounded by the frame (20).

3. The mattress assembly (10) according to claim 2, wherein the frame (20) and the thermoplastic elastomer grid layer (22) are connected with each other in a permanent manner such that they form a single layer (14) and/or wherein the thermoplastic elastomer (TPE) grid layer (22) of the first additional layer (14) has a hardness that is higher compared to the hardness of the frame (20), particularly by 10 % to 20 %, and a minimum netto density that is higher than the minimum netto density of the frame (20), particularly by a factor of 5 to 10, preferably by a factor of 6 to 8, and/or wherein the thermoplastic elastomer (TPE) grid layer (22) has a minimum netto density of 230 kg/m³ and/or a hardness of 2.8.

4. The mattress assembly (10) according to any one of the preceding claims, wherein the mattress assembly (10) comprises at least three second additional layers (16, 17, 18), wherein each of the at least three second additional layers (16, 17, 18) are made by different materials, particularly different foams, and/or wherein all second additional layers (16, 17, 18) have different characteristics, particularly a minimum density and/or a different hardness, and/or wherein the first additional layer (14) and the at least one additional second layer (15) have the same height, particularly 15 mm.

5. The mattress assembly (10) according to one of the preceding claims, wherein the spring core assembly (12) comprises a first type spring pocket (36) and a second type spring pocket (38), wherein both types of spring pockets (36, 38) have the same bottom fabric (30) and the same top fabric (32), wherein the first type spring pocket (36) has a first spring coil (34) that is located between the bottom fabric (30) and the top fabric (32), wherein the second type spring pocket (38) has a second spring coil (34) that is located between the bottom fabric (30) and the top fabric (32), and wherein the first spring coil (34) and the second spring coil (34) are different, preferably wherein the first spring coil (34) and the second spring coil (34) have different wire diameters, in particular wherein the wire diameter of the first spring coil (34) is smaller than the wire diameter of the second spring coil (34), and/or wherein the ratio of the wire diameter of the first spring coil (34) to the wire diameter of the second spring coil (34) is between 0.72 and 0.95, particularly 0.9 and/or wherein the wire diameter of the first spring coil (34) is between 1.6 mm and 1.9 mm, particularly 1.7 mm, and/or wherein the wire diameter of the second spring coil (34) is between 1.8 mm and 2.2 mm, particularly 1.9 mm.

6. The mattress assembly (10) according to any one of the preceding claims, wherein the spring core assembly (12) is made edge-to-edge without lateral foam material such that the mattress assembly (10) is compressible, foldable and/or rollable.

7. The mattress assembly (10) according to any one of the preceding claims, wherein the spring core assembly (12), the first additional layer (14) and the at least one second additional layer (15) are loosely placed on top of each other.

8. The mattress assembly (10) according to any one of the preceding claims, wherein the spring core assembly (12) is at least partially, preferably completely, surrounded by a spring core assembly envelope (40) having a shape of a cuboid with a bottom wall (42), a top wall (44) and four side walls (46).

9. The mattress assembly (10) according to claim 8, wherein the bottom wall (42), the top wall (44) and the four side walls (46) of the spring core assembly envelope (40) are made of fabric, particularly the bottom wall (42) and the top wall (44) are made of the same fabric and the side walls (46) are made of a different fabric.

10. The mattress assembly (10) according to one of the claims 8 and 9, wherein the spring core assembly envelope (40) comprises a first zip fastener (48) for opening and closing the spring core assembly envelope (40), preferably arranged at an edge (50) between the bottom wall (42) and at least one of the four side walls (46).

11. The mattress assembly (10) according to claim 10, wherein the first zip fastener (48) extends at least along the length of one side wall (46), preferably the first zip fastener extends at least along the length of one side wall (46) and at least partially along the length of an adjacent side wall (46) such that the spring core assembly envelope (40) is openable in order to remove and/or adjust the spring core assembly (12), wherein at least one part of the bottom wall (42) remains permanently attached to the spring core assembly envelope (40), in particular wherein the spring core assembly envelope (40) is openable completely.

12. The mattress assembly (109 according one of the claims 8 to 11, wherein the at least one second additional layer (15) is placed on top of the spring core assembly envelope (40) such that the at least one second additional layer (15) is separated from the spring core assembly (12) by the top wall (44) of the spring core assembly envelope (40).

13. The mattress assembly (10) according to any one of the claims 8 to 12, wherein the at least one second additional layer (15) is covered by a cover (52), in particular a cover (52) made of a fabric such that the at least one second additional layer (15) is disposed between the cover (52) and the spring core assembly envelope (40).

14. The mattress assembly (10) according to claim 13, wherein the spring core assembly envelope (40) has a chain (56) for a second zip fastener (54) configured to engage a corresponding chain (58) of the second zip fastener (54) of the cover (52) such that the cover (52) together with the top wall (44) of the spring core assembly envelope (40) forms a chamber for the at least one second additional layer (15), in particular wherein the chain (58) of the second zip fastener (54) of the cover (52) is located at the edge (60) between the top wall (44) and the side walls (46) of the spring core assembly envelope (40) and extends at least along the length of one side wall (46), preferably along the circumference of the top wall (44), preferably such that the cover (52) is fully removable from the spring core assembly envelope (40) in order to remove and/or adjust at least the second additional layer (15).

15. A method of adjusting a mattress assembly (10), particular the mattress assembly (10) according to any of the preceding claims, wherein a spring core assembly (12) of the mattress assembly (10) is at least partially, preferably completely, surrounded by a spring core assembly envelope (40) having a shape of a cuboid with a bottom wall (42), a top wall (44) and four side walls (46), wherein at least one additional layer (14, 15) is covered by a cover (52) such that the at least one additional layer (14, 15) is disposed between the cover (52) and the spring core assembly envelope (40), and wherein the spring core assembly envelope (40) has a chain (56) for a zip fastener (54) configured to engage a corresponding chain (58) of the zip fastener (54) of the cover (52) such that the cover (52) together with the top wall (44) of the spring core assembly envelope (40) forms a chamber for the at least one additional layer (14, 15), wherein the method comprises the steps of:

Unzipping the zip fastener (54) to obtain access to the chamber for the at least one additional layer (14, 15),

Removing the at least one additional layer (14, 15) from the chamber, Inserting at least one new additional layer (14, 15) into the chamber, and Zipping the zip fastener (54) in order to close the chamber.