WO2024213674A1

WO2024213674A1 - Spring core assembly and mattress assembly

Info

Publication number: WO2024213674A1
Application number: PCT/EP2024/059913
Authority: WO
Inventors: Majid Kardeh; Rose Rogin GILBERT; Manuel Mueller
Original assignee: Emma Sleep Gmbh
Priority date: 2023-04-12
Filing date: 2024-04-11
Publication date: 2024-10-17
Also published as: EP4445799A1

Abstract

The invention relates to a spring core assembly for a mattress assembly. The spring core assembly comprises at least one spring pocket that has a bottom fabric, a top fabric as well as at least one spring coil located between the bottom fabric and the top fabric. A grammage of the bottom fabric is different to a grammage of the top fabric. Further, a mattress assembly is described.

Description

Spring core assembly and mattress assembly

The invention relates to a spring core assembly for a mattress assembly. Further, the invention relates to 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.

Foam 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.

The invention provides a spring core assembly for a mattress assembly. The spring core assembly comprises at least one spring pocket that has a bottom fabric, a top fabric as well as at least one spring coil located between the bottom fabric and the top fabric. A grammage of the bottom fabric is different to a grammage of the top fabric. Thus, the bottom fabric and the top fabric form the spring pocket at least partly in which the at least one spring coil is located. The spring pocket is formed in such that there is preferably a direct contact between the at least one spring coil and the bottom fabric and/or the top fabric. Particularly, a direct contact may be established between an upper end (portion) of the at least one spring coil and the top fabric. Further, a direct contact may be established between a lower end (portion) of the at least one spring coil and the bottom fabric. Moreover, the at least one spring coil may be encompassed completely by the spring pocket. The spring core assembly comprises at least one of the spring pockets. In other words, the spring pocket is the smallest independent unit of the spring core assembly.

Accordingly, the spring core assembly that may be used as an independent spring core layer within the mattress assembly comprises spring pockets with different fabrics above and beneath the respective spring coils. This ensures that the spring core assembly, particularly the respective spring coil, has an improved support.

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.

The spring core assembly has several spring pockets, for instance 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. Generally, the bottom fabric and the top fabric are located on opposite sides of the respective spring pocket(s).

For instance, the spring core assembly has a height of 195 mm.

An aspect provides that 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, 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.

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 pocket glue vertical distance can be between 65 mm and 75 mm, preferably 70 mm.

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, e.g. a middle axis 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.

According to the invention 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.

The invention further provides a mattress assembly that comprises the spring core assembly as described above. The mattress assembly further comprises at least one additional layer located on top of the spring core assembly.

As mentioned above, the spring core assembly may relate to a bottom layer of the mattress assembly such that the at least one additional layer is put on top of the spring core assembly. For instance, the additional layer located on top of the spring core assembly may be a foam layer. The additional layer may be directly glued to the spring core assembly in order to interconnect both with each other. A hot melt glue may be used for adhering the additional layer to the spring core assembly.

Alternatively, the at least one additional layer may be zipped by a zip fastener to the spring core assembly. Therefore, the spring core assembly, preferably the top fabric of the spring core assembly, comprises a first part of a chain of the zip fastener and the additional layer comprises the corresponding second part of the chain. Preferably, the additional layer comprises a cover made of fabric, wherein the cover has a chain for a zip fastener corresponding to the chain for the zip fastener at the spring core assembly.

In a preferred embodiment, the chains of the zip fastener extend over the length of at least one side of the spring core assembly and/or the additional layer, preferably the chains extend over the entire circumference of the spring core assembly and/or the additional layer. In other words, the at least one additional layer can be attached to the mattress assembly by a cover which can be zipped to the spring core assembly. Even more preferably, there is a separation layer separating the spring core assembly from the at least one additional layer so that the mattress assembly has two chambers, one chamber for the spring core assembly and second chamber for the at least one additional layer.

An aspect provides that the mattress assembly is a stack assembly that comprises the spring core assembly, a first additional layer and a second additional layer, wherein the first and second additional layers are made by different materials, particularly different foams. Therefore, the mattress assembly has at least three different layers that are stacked on each other, thereby providing the mattress assembly stack. The three different layers, namely the mattress assembly, the first additional layer and the second additional layer, each have different characteristics, e.g. a different minimum netto density and/or a different hardness. Moreover, the different layers may be manufactured by different materials, for instance different foams.

Generally, the hardness may be measured according to ISO 3386. In a specific embodiment, the spring core assembly is a bottom layer of the mattress assembly, wherein a third layer is glued to the spring core assembly. The second layer is glued to the third layer. The first layer is glued to the second layer. All layers have different characteristics, for instance a different minimum density and/or a different hardness. Therefore, three additional layers are provided that are stacked on each other and located on top of the mattress assembly. Moreover, different kinds of adhesives may be used to adhere the respective layers among each other. As indicated above, a hot melt adhesive or a water-based glue may be used in order to connect the spring core assembly with the third layer, whereas the second layer is connected to the third layer by means of a water based adhesive. In addition, the first layer is connected to the second layer by means of a water based adhesive. However, different adhesives may be used, e.g. a water based adhesive for connecting the spring core assembly with the third layer and/or a hot melt adhesive or a water-based glue for connecting the second to the third layer or rather the first layer to the second layer. As described above, it is also possible to zip the additional layers to the spring core assembly by a zipper.

According to one embodiment, the three additional layers are glued together and covered by a cover comprising a chain for the zip fastener in order to connect the cover to the spring core assembly, thereby forming a chamber for the three additional layers.

According to another embodiment, the three additional layers are simply stacked on top of each other, but are not glued together. The stacked additional layers are covered by a cover having a zip fastener to connect the cover to the spring core assembly and to form a common chamber for the three additional layers. As the three additional layers are not glued together, this design allows the replacement of at least one of the three additional layers, whereas the other one or two additional layers remain.

In a further embodiment, each of the three additional layers is covered and separated from the other additional layers by a cover having a chain of a 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 cover of the third additional layer and the cover of the third additional layer can be zipped to the spring core assembly. In other words, each of the three additional layers is placed between two covers or between a cover and the spring core assembly, so that each of the three additional layers is in direct contact with at least one cover. Two covers or a cover and the spring core assembly form a zippable layer pocket for the additional layers.

Each embodiment allows at least one of the three additional layers to be exchanged and/or rotated so that e.g. the hardness can be adjusted for each mattress assembly individually. Moreover, it is also possible to additionally have a separation layer separating the additional layers from the spring core layer and resulting in a separate chamber for the additional layers.

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

A comfort foam is associated with the third layer that is directly glued or zipped to the spring core assembly. For instance, the third layer has a minimum netto density of 30 kg/m³ and/or a hardness of 3 kPa. Alternatively, the third layer has a minimum netto density of 31 kg/m³ and/or a hardness of 2.8 kPa

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

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

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

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.

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 wire 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.

The additional layers, namely the foam layers, in the combination of the mattress assembly ensure pressure relief and comfort and make the mattress assembly more durable.

Generally, the additional layers, namely the foam layers, are made without cutouts and/or recesses, e.g. as full material layers.

The additional layers may have the same height, e.g. 15 mm.

The spring core assembly may have a height of 200 mm.

The entire mattress assembly may have a height of 245 mm.

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 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 3 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, and

Figure 4 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.

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. Between the first additional layer 14 and the spring core assembly 12, the mattress assembly 10 further comprises a second additional layer 16 as well as a third additional layer 18.

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 additional layers 14 to 18 are made of a foam.

Particularly, the different layers 12-18 are interconnected with each other by means of an adhesive. Depending on the types of layers to be interconnected, a different adhesive may be used.

For instance, the first layer 14 is glued to the second layer 16 by means of a water-based glue. The second layer 16 is adhered to the third layer 18 by means of a water-based glue as well, whereas a hot melt glue is provided between the spring core assembly 12 and the third layer 18.

Accordingly, the connection between a foam layer, namely the third layer 18, and the spring core assembly 12 is established by means of the hot melt glue, whereas a water-based glue is used for interconnecting foam layers.

In the shown embodiment, the first to third additional layers 14-18 have the same height, namely 15 mm, whereas the spring core assembly 12 has a height of 195 mm, resulting in an overall height of 240 mm.

As discussed above, the first to third layers 14-18 are made of a foam, particularly different foams. Accordingly, the respective characteristics of the additional layers 14-18 may differ.

For instance, the first layer 14 is made by a hypersoft foam that has a minimum netto density of 32 kg/m³ and a hardness of 1.5 kPa. The second additional layer 16 may be made by a visco-memory foam that has a minimum netto density of 50 kg/m³ and a hardness of 1.5 kPa.

The third additional layer 18 may be made by a comfort foam that has a minimum netto density of 30 kg/m³ and a hardness of 3 kPa.

The spring core assembly 12 comprises several spring pockets 20 that are schematically shown in Figure 1. The spring pockets 20 each comprise a bottom fabric 22 as well as a top fabric 24 via which the spring pockets 20 are glued to the third additional layer 18.

Each spring pocket 20 has a spring coil 26 that is located between the bottom fabric 22 and the top fabric 24. The spring coils 26 are made of a metal wire.

The respective fabrics, namely the bottom fabric 22 and the top fabric 24, have different grammages. For instance, the grammage of the bottom fabric 22 is higher than the grammage of the top fabric 24. The several spring pockets 20 may have their own bottom fabric 22 and/or top fabric 24. Alternatively, the several spring pockets 20 may share a common bottom fabric 22 and/or a common top fabric 24.

For instance, a ratio of the grammage of the top fabric 24 to the grammage of the bottom fabric 22 is between 0.4 to 0.6, particularly 0.5.

Specifically, the grammage of the top fabric 24 may be between 60 g/m³ and 80 g/m³, particularly 65 g/m³, whereas the grammage of the bottom fabric 22 is between 100 g/m³ and 160 g/m³, particularly 130 g/m³.

In fact, the bottom fabric 22 provides a support surface of the entire mattress assembly 10 as shown in Figure 1.

Therefore, these different grammages of the fabrics 22, 24 ensure proper support of the spring coils 26 located within the spring pockets 20 as well as proper support for a user of the entire mattress assembly 10.

For instance, the bottom fabric 22 and the top fabric 26 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 20, namely a first type spring pocket 28 as well as a second type spring pocket 30.

The different type spring pockets 28, 30 distinguish from each other by their respective spring coils 26, particularly the wire diameter of the respective spring coils 26.

In fact, the first type spring pocket 28 has a first spring coil 42 with a wire diameter between 1.6 mm and 1.9 mm, particularly between 1.6 mm and 1.8 mm, preferably 1.7 mm whereas the wire diameter of the second spring coil 34 is between 1.8 mm and 2.2 mm, particularly between 1.8 mm and 2 mm, preferably 1.9 mm.

For instance, the ratio of the wire diameter of the first spring coil 32 to the wire diameter of the second spring coil 34 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 20.

Each zone A-l comprises only one type of spring pocket 20, namely either the first type spring pocket 28 or the second type spring pocket 30.

The nine different zones each comprise at least one line of the certain type of spring pockets 20.

Generally, a line of a specific type of spring pockets 20 means that the respective spring pockets 20 are made of the same type and interconnected with each other by welding. The line of spring pockets 20 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 20, irrespective of the specific type of spring pocket 20. In fact, the first zone A comprises two lines of the second type spring pockets 30. The adjacent second zone B comprises six lines of the first type spring pockets 28. The third zone C comprises six lines of the first type spring pockets 30,. The fourth zone D comprises one single line of the first type spring pocket 28. The fifth zone E comprises two lines of the second type spring pockets 30. The sixth zone F comprises one single line of the first type spring pockets 28. The seventh zone G comprises six lines of the second type spring pockets 30. 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 30.

In the shown embodiment, the spring core assembly 12 has a length L of 190 cm. Therefore, the spring core assembly 12 comprises 32 lines wherein these 32 lines are interconnected with each other by gluing.

As indicated above, the respective spring pockets 20 of one line, particularly their respective spring coils 26, are interconnected with each other by welding, thereby establishing the line.

In contrast thereto, the spring pockets 20 of adjacent lines are connected with each other by gluing.

Generally, the spring pockets 20, particularly their spring coils 26, are welded to each along a first dimension, e.g. the width W.

Moreover, the spring pockets 20 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 20 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 20 along the width W. In Figure 2, 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 20, wherein each line comprises fourteen spring pockets 20 in the shown embodiment.

Moreover, the different zones may be established by two different types of spring pockets 20, namely either the first spring pocket 28 or the second type spring pocket 30.

The first zone A comprises two lines of the second type spring pocket 30. The adjacent second zone B comprises six lines of the first type spring pocket 28. The adjacent third zone C comprises five lines. The adjacent fourth zone D comprises one single line of the first type spring pocket 28. The adjacent fifth zone E comprises two lines of the second type spring pocket 30. The adjacent sixth zone F comprises one single line of the first type spring pocket 28.

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 30. The adjacent eighth zone H comprises only one line of the first type spring pocket 28. The adjacent ninth zone I comprises five lines of the second type spring pocket 30. The adjacent tenth zone J comprises six lines of the first type spring pocket 28. Finally, the adjacent eleventh zone K comprises two lines of the second type spring pocket 30.

The additional layers 14-18 are similar to the ones of the first embodiment shown in Figure 1 and, thus, reference is made thereto. In Figure 3, 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 32 lines of spring pockets 20. In fact, the distribution of the different types of spring pockets 20, namely the first type spring pockets 28 and the second type spring pockets 30, 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 additional layers 14-18 are made differently.

Generally, the additional layers 14-18 each have a height of 15 mm similar to the first embodiment. Moreover, these additional layers 14-18 are also adhered to each other by means of the same adhesive(s).

However, the characteristics of the additional layers 14-18 differ from the ones of the first embodiment, e.g. due to different materials used for the additional layers 14-18.

In fact, the first additional layer 14 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 16 is made of a comfort foam that has a minimum netto density of 34 kg/m³ and a hardness of 2.5 kPa. The third additional layer 18 that is directly adhered to the spring core assembly 12 is also made of a comfort foam with a minimum netto density of 31 kg/m³ and a hardness of 2.8 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 4, a fourth embodiment is shown that is a combination of the second embodiment shown in Figure 2 and the third embodiment shown in Figure 3, 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 additional layers 14-18 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 2, but the additional layers 14 to 18 discussed with respect to the third embodiment shown in Figure 3 Therefore, reference is made to the explanations given above with regard to the second and third embodiments.

Claims

1. A spring core assembly for a mattress assembly, wherein the spring core assembly comprises at least one spring pocket that has a bottom fabric, a top fabric as well as at least one spring coil located between the bottom fabric and the top fabric, characterized in that a grammage of the bottom fabric is different to a grammage of the top fabric.

2. The spring core assembly according to claim 1, wherein the grammage of the bottom fabric is higher than the grammage of the top fabric.

3. The spring core assembly according to claim 1 or 2, wherein a ratio of the grammage of the top fabric to the grammage of the bottom fabric is between 0.4 and 0.6, particularly 0.5.

4. The spring core assembly according to any of the preceding claims, wherein the grammage of the top fabric is between 60 g/m² and 80 g/m², particularly 65 g/m², and/or wherein the grammage of the bottom fabric is between 100 g/m² and 160 g/m², particularly 130 g/m².

5. The spring core assembly according to any of the preceding claims, wherein the spring core assembly comprises a first type spring pocket and a second type spring pocket, wherein both types of spring pockets have the same bottom fabric and the same top fabric, wherein the grammage of the bottom fabric is different to the grammage of the top fabric, wherein the first type spring pocket has a first spring coil that is located between the bottom fabric and the top fabric, wherein the second type spring pocket has a second spring coil that is located between the bottom fabric and the top fabric, and wherein the first spring coil and the second spring coil are different.

6. The spring core assembly according to claim 5, wherein the first type spring pocket and the second type spring pocket are neighbored and glued to each other.

7. The spring core assembly according to claim 5 or 6, wherein the first spring coil and the second spring coil have different wire diameters, in particular wherein the wire diameter of the first spring coil is smaller than the wire diameter of the second spring coil.

8. The spring core assembly according to any one of claims 5 to 7, wherein the ratio of the wire diameter of the first spring coil to the wire diameter of the second spring coil is between 0.72 and 0.95, particularly 0.9.

9. The spring core assembly according to any one of claims 5 to 8, wherein 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 and/or wherein 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.

10. The spring core assembly according to any one of claims 5 to 9, wherein several first type spring pockets are connected in series, particularly by welding, thereby forming a line of first type spring pockets and/or wherein several second type spring pockets are connected in series, particularly by welding, thereby forming a line of second type spring pockets.

11. The spring core assembly according to any one of claims 5 to 10, wherein 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 and/or wherein 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.

12. The spring core assembly according to any one of the preceding claims, wherein the spring core assembly is symmetrical with respect to two symmetrical lines intersecting each other in a center of the spring core assembly, in particular wherein the symmetrical lines are perpendicular to each other.

13. A mattress assembly comprising the spring core assembly according to any one of the preceding claims, wherein the mattress assembly further comprises at least one additional layer located on top of the spring core assembly.

14. The mattress assembly according to claim 13, wherein the mattress assembly is a stack assembly that comprises the spring core assembly, a first additional layer and a second additional layer, wherein the first and second additional layers are made by different materials, particularly different foams.

15. The mattress assembly according to claim 14, wherein the spring core assembly is a bottom layer of the mattress assembly, wherein a third layer is glued or zipped to the spring core assembly, wherein the second layer is glued or zipped to the third layer, wherein the first layer is glued or zipped to the second layer, and wherein all layers have different characteristics, particularly a different minimum density and/or a different hardness.