EP3400844A1

EP3400844A1 - Spring core with pocketed coil and foam springs

Info

Publication number: EP3400844A1
Application number: EP17170763.1A
Authority: EP
Inventors: Niels Albæk; Morten JØRGENSEN
Original assignee: L&P Swiss Holding GmbH
Current assignee: L&P Swiss Holding GmbH
Priority date: 2017-05-12
Filing date: 2017-05-12
Publication date: 2018-11-14

Abstract

A pocket spring core includes a plurality of first pocketed spring elements (21). The first pocketed spring elements (21) are each formed of a pocket (22) and a coil spring (23) enclosed in the pocket (22). Further, the spring core includes a plurality of second pocketed spring elements (31), the second pocketed spring elements (31) are each formed of a pocket (32) and a foam spring (33) enclosed in the pocket (32).

Description

FIELD OF THE INVENTION

The invention relates to a spring core with pocketed springs, a bedding or seating product comprising a spring core with pocketed springs, and method of manufacturing a spring core with pocketed springs.

BACKGROUND

Spring cores are widely used in seating or bedding products. Such spring cores may be made from a matrix of multiple springs joined together directly as by helical lacing wires, or indirectly as by fabric within which each individual spring is contained. Pocket spring cores in which springs are respectively contained in a pocket of fabric are popular, due to the comfort and luxury feel provided by pocket spring cores.
In view of user comfort, it is known to provide spring cores with springs having different characteristics. For example, varying degrees of hardness may be achieved changing the gauge of the wire from which the springs are manufactured. In some cases, coil springs formed of a metal wire may be combined with foam material. For example, WO00/45676 describes a spring core with pocketed coil springs where foam cylinders may be inserted into the coil springs to achieve different degrees of firmness. Further, foam material may also be added to wire based coil springs to reduce noise, as for example described in US8266745B2 .
Notwithstanding the above, there is a need for spring core constructions which allow for efficiently tailoring the characteristics of the spring core while at the same time maintaining a low complexity.

SUMMARY

According to an embodiment, a pocket spring core is provided, e.g., for incorporation into a bedding product, such as a mattress, or for incorporation into a seating product, such as a sofa cushion or chair cushion. The spring core comprises a plurality of first pocketed spring elements. The first pocketed spring elements are each formed of a pocket and at least a coil spring enclosed in the pocket. Further, the spring core comprises a plurality of second pocketed spring elements. The second pocketed spring elements are each formed of a pocket and a foam spring enclosed in the pocket. Accordingly, some pockets of the spring core each include a coil spring, while other pockets include a foam spring, but no coil spring. The foam springs of the second pocketed spring elements may correspond to foam pegs or cylinders. The coil springs of the first pocketed spring elements may be formed of a metal wire, e.g., steel wire. By using the first pocketed spring elements and the second pocketed spring elements in combination, the characteristics of the spring core may be efficiently varied between the different pocketed spring elements. For example, the first pocketed spring elements may be predominantly arranged in areas where a higher stability of the spring core is desired, e.g., close to the edges or in end sections of a mattress. The second pocketed spring elements may be arranged in areas where a higher flexibility of the spring core is desired, e.g., in a central section where in typical usage parts of a user's body, like shoulders or pelvis, will come to rest. The increased flexibility may provide enhanced comfort for the user. Further, it is also possible to mix the first pocketed spring elements and the second pocketed spring elements according to various interleaving patterns, thereby tailoring the characteristics of the spring core to meet desired characteristics in different areas or sections of the spring core.
According to an embodiment, in an uncompressed state the coil springs of the first pocketed spring elements have a different height than the foam springs of the second pocketed spring elements. For example, the height of the coil springs could be higher than that of the foam springs. Alternatively, the height of the foam springs could be higher than that of the coil springs. In each case, the springs having the higher height determine the characteristics of the spring core upon initial compression, in a range between the higher height and the lower height. In the case of compression to beyond the lower height, both the springs having the higher height and the springs having the lower height will contribute to the characteristics of the spring core, which for example allows for achieving a stiff feeling in the case of strong compression. Similar effects may also be achieved if in an uncompressed state the coil springs of the first pocketed spring elements have different heights and/or if in an uncompressed state the foam springs of the second pocketed spring elements have different heights. As a general rule, pocketed spring elements with coil springs or foam springs of various heights may be mixed in various patterns to tailor the characteristics of the spring core. According to an embodiment, the coil springs of the first pocketed spring elements comprise first coil springs, which in an uncompressed state have the same height as at least some of the foam springs of the second pocketed spring elements, and second coil springs which in an uncompressed state have a different height than at least some of the foam springs of the second pocketed spring elements. Similarly, the foam springs of the second pocketed spring elements may comprise first foam springs, which in an uncompressed state have the same height as at least some of the coil springs of the first pocketed spring elements, and second foam springs which in an uncompressed state have a different height than at least some of the coil springs of the first pocketed spring elements. Using coil springs and foam springs of the same height may for example help to achieve a desired height profile of the spring core. For example, the common height of the coil springs and the foam springs could be used to define a substantially planar upper surface of the spring core.
According to an embodiment, for at least some of the first pocketed spring elements the pocket encloses not only the coil spring, but also a foam spring. That is to say, at least some of the first pocketed spring elements could include a hybrid coil-foam spring. For example, the foam spring could be a foam cylinder or peg which is inserted into the coil spring. The coil spring and the foam spring of the first pocketed spring element may then also have different heights. Combining a coil spring and a foam spring in the same pocket may further enhance the flexibility with respect to tailoring the characteristics of the spring core.
According to an embodiment, the pocket spring core has multiple sections. These sections may correspond to areas where in typical usage scenarios specific parts of a user's body will come to rest. By way of example, the pocket spring core could have a head section which has characteristics tailored to support the user's head, a shoulder section, which has characteristics tailored to support the user's shoulders or upper body, a middle section which has characteristics tailored to support the user's lower body or pelvis, a leg section which has characteristics tailored to support the user's legs and knees, and a feet section which has characteristics tailored to support the user's feet. For individually tailoring the characteristics of the different sections, at least some of the multiple sections of the spring core may differ with respect to a distribution of the first pocketed spring elements and the second pocketed spring elements.
According to an embodiment, at least some of the first pocketed spring elements are interleaved between at least some of the second pocketed spring elements, and/or at least some of the second pocketed spring elements are interleaved between at least some of the first pocketed spring elements. Various interleaving patterns can be used. By interleaving the first pocketed spring elements and the second pocketed spring elements, the spring core can be provided with local characteristics which are determined by both the coil springs of the first pocketed spring elements and the foam springs of the second pocketed spring elements. By way of example, if in an interleaving pattern one of the first pocketed spring elements is arranged adjacent to one of the second pocketed spring elements, the spring core may at the position of these two pocketed spring elements be provided with a local characteristic which is defined by the characteristics of the coil spring of the first pocketed spring element and by the characteristics the foam spring of the second pocketed spring element.
According to an embodiment, the foam springs of at least some of the second pocketed spring elements are formed of memory foam. Usage of memory foam provides a further degree of freedom with respect to imparting desired characteristics to the spring core.
According to a further embodiment, a bedding or seating product is provided which comprises a spring core as described above. The bedding or seating product may for example correspond to a bed, a mattress, a sofa, a chair, a sofa cushion, or a chair cushion.
According to a further embodiment, a method is provided which can be used for manufacturing a pocket spring core as described above. According to the method, a plurality of coil springs is provided. Each of the coil springs is enclosed in a respective pocket, thereby forming the first pocketed spring elements. Further, a plurality of foam springs is provided. Each of the foam springs is enclosed in a respective pocket to form the second pocketed spring elements. Further, the first pocketed spring elements and the second pocketed spring elements are joined, thereby forming the pocket spring core.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be described with reference to the accompanying drawings.

FIG. 1 is a perspective view, partially broken away, of a mattress including a pocket spring core of an embodiment.
FIG. 2 illustrates an example of pocketed spring elements as used in an embodiment.
FIG. 3 illustrates an example of arranging different types of pocketed spring elements according to an embodiment.
FIG. 4 illustrates a further example of pocketed spring elements as used in an embodiment.
FIG. 5 illustrates a further example of arranging different types of pocketed spring elements according to an embodiment.
FIG. 6 illustrates a further example of pocketed spring elements as used in an embodiment.
FIG. 7 illustrates a further example of arranging different types of pocketed spring elements according to an embodiment.
FIG. 8 illustrates a further example of pocketed spring elements as used in an embodiment.
FIG. 9 illustrates a further example of arranging different types of pocketed spring elements according to an embodiment.
FIG. 10 illustrates a further example of pocketed spring elements as used in an embodiment.
FIG. 11 shows a flowchart for illustrating a spring core manufacturing method according to an embodiment.
FIG. 12 illustrates a further example of arranging different types of pocketed spring elements according to an embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Exemplary embodiments of the invention will be described with reference to the drawings. While some embodiments will be described in the context of specific fields of application, such as in the context mattresses, the embodiments are not limited to this field of application. The features of the various embodiments may be combined with each other unless specifically stated otherwise. Throughout the following description, same or like reference numerals refer to same or like components or mechanisms.
FIG. 1 shows a cushion in the form of a single-sided mattress 1 incorporating a pocket spring core 2 according to an embodiment. This cushion or mattress 1 comprises the pocket spring core 2 over the top of which there is a foam pad 4 covered by a fiber pad 5. This complete assembly is mounted upon a base 7 and is completely enclosed within an upholstered covering material 6. While one embodiment of the invention described herein is illustrated and described as being embodied in a single-sided mattress, it is equally applicable to double-sided mattresses or seating cushions. In the event that it is utilized in connection with a double-sided mattress, the bottom side of the spring core 2 may have a foam pad applied over the bottom side of the spring core and that pad is in turn covered by a fiber pad of cushioning material.
The pocket spring core 2 is manufactured from multiple strings 3 of pocket spring elements. The strings 3 may respectively be formed by providing a fabric layer, inserting a spring into the fabric layer, folding the fabric layer so as to cover the spring either before or after insertion of the spring, and applying longitudinal and transverse seams, e.g. by welding. Each string 3 may extend across the full width of the product 1. The strings 3 may be connected in side-by-side relationship as, for example, by gluing the sides of the strings 3 together in an assembly machine, so as to create an assembly or matrix of springs having multiple rows and columns of pocketed springs bound together, such as by gluing, welding or any other conventional assembly process commonly used to create pocket spring cores. As a result, the pocket spring core 2 forms a unitary structure having a width W and length L. The pocket spring core 2 may be fabricated using various kinds of conventional pocket spring manufacturing machine and by any conventional spring pocketing process, which allow for not only using coil springs formed of a metal wire, but also foam springs formed of a foam material.
In the pocket spring core 2 of any one of the embodiments described herein, the fabric from which the pockets are formed may be semi-impermeable. The fabric may be configured such that it has a greater resistance to air flow directed from an exterior to an interior of the pocket than to air flow directed from an interior to an exterior of the pocket. The seams which delimit the respective pockets may be sinusoidal welded seams, e.g., formed by ultrasonic welding.
In the embodiments described herein, the spring core 2 includes at least two different types of pocketed spring elements: first pocketed spring elements with a pocket with an enclosed coil spring and second pocketed spring elements with a pocket with an enclosed foam spring, but no coil spring. In some cases, at least some of the first pocketed spring elements could also include both a coil spring and a foam spring. The coil springs may be formed of a metal wire. The foam springs may be formed of various foam materials, e.g., a flexible polyurethane foam, a visco-elastic foam, a latex rubber foam, or a memory foam.
In the illustrated embodiments, combing coil springs and foam springs in the same spring core enables utilizing their unique performance advantages in different points and zones to achieve optimized balance of firmness, durability and soft-touch feel, as well as enhanced air ventilation as compared to using only foam.
Fig. 2 illustrates an example of pocketed spring elements 21, 31 which may be used in the spring core 2. As illustrated, each pocketed spring element 21, 31 is formed of a pocket 22, 32 and a spring 23, 33 enclosed within the pocket 22, 32. As mentioned above, the pockets 22, 32 may be formed from one or more fabric layers, typically a non-woven fabric material, such as a non-woven polypropylene based fabric. In the case of the pocketed spring elements 21, the pocket 22 encloses a coil spring 23. An interior portion of the coil spring 23 is hollow. In the case of the pocketed spring elements 31, the pocket 32 encloses a foam spring. The coil springs 23 and the foam springs 33 are compressible in a height direction H, which is perpendicular to the width and length directions of the pocket spring core 2. The pocketed spring elements 21, 31 are illustrated as being part of the same string and separated by seams 40.
As illustrated, the pocketed spring elements 21 are interleaved with the pocketed spring elements 31. In the illustrated example, this interleaving is based on an interleaving pattern where the pocketed spring elements 21 alternate in a one-to-one sequence with the pocketed spring elements 31. However, other interleaving patterns could be used as well.
Fig. 3 shows an example of how the pocketed spring elements 21, 31 could be distributed in a plane defined by the width direction and the length direction of the spring core 2. In the illustration of Fig. 3, open circles denote positions of the pocketed spring elements 21 with the coil springs 23, and dotted circles denote positions of the pocketed spring elements 31 with the foam springs 33. As can be seen, the spring core 2 includes multiple sections 11, 12, 13, 14, 15 which have different distributions of the pocketed spring elements 21, 31. In the illustrated example, the section 11 is a head section which in typical usage scenarios of the mattress 1 would support the head of a user, the section 12 is a shoulder section which in typical usage scenarios of the mattress 1 would support the shoulders or upper body of the user, the section 13 is a middle section which in typical usage scenarios of the mattress 1 would support the lower body or pelvis of the user, the section 14 is a leg section which in typical usage scenarios of the mattress 1 would support the legs or knees of the user, and the section 15 is a feet section which in typical usage scenarios of the mattress 1 would support the feet of the user. In the illustrated example, the spring core 2 has a symmetrical configuration in which the section 11 is similar to the section 15 and the section 12 is similar to the section 15. Accordingly, the mattress can also be used for the opposite orientation of the user, i.e., with the head at the section 15. Accordingly, the section 11 at the same time acts a further feet section, the section 12 at the same time acts a further leg section, the section 14 acts as a further shoulder section, and the section15 at the same time acts a further head section. However, it is noted that also configurations could be used where the sections 11, 12, 13, 14, 15 each have a different configuration.
In the example of Fig. 3, the sections 11 and 15 include only the pocketed spring elements 21 with the coil springs 23. In this way, these sections can be provided with a good stability. The sections 12, 13, and 14 include both the pocketed spring elements 21 with the coil springs 23 and the pocketed spring elements 31 with the foam springs 33. In this way, the sections 12, 13, and 14 may be provided with a softer and less elastic characteristic than the sections 11 and 15. In the sections 12 and 14, the relative proportion of the pocketed spring elements 31 with the foam springs 33 is higher than in the section 13. In this way, the section 13 may be provided with a stiffer an more elastic compression characteristic than the sections 12 and 14.
In the examples of Figs. 2 and 3, the coil springs 23 and the foam springs 33 have the same heights. However, in some cases it may be beneficial to use coil springs and foam springs of different heights. Fig. 4 illustrates a corresponding example of pocketed spring elements 21 and 31'.
Also in the example of Fig. 4, each pocketed spring element 21, 31' is formed of a pocket 22, 32' and a spring 23, 33' enclosed within the pocket 22, 32', and the pockets 22, 32' may be formed from one or more fabric layers, typically a non-woven fabric material, such as a non-woven polypropylene based fabric. In the case of the pocketed spring elements 21, the pocket 22 encloses a coil spring 23. An interior portion of the coil spring 23 is hollow. In the case of the pocketed spring elements 31', the pocket 32' encloses a foam spring. The coil springs 23 and the foam springs 33' are compressible in a height direction H, which is perpendicular to the width and length directions of the pocket spring core 2. The pocketed spring elements 21, 31' are illustrated as being part of the same string and separated by seams 40. The foam springs 33' of the pocketed spring elements 31', and also the corresponding pockets 32', have a lower height than the coil springs 23 of the pocketed spring elements 21. Accordingly, when starting to compress the mattress 1 in an area which includes the pocketed spring elements 21 and 31', initially only the coil springs 23 are compressed. Only when the coil springs 23 are compressed so far that they have the same height as the foam springs 33', also the foam springs 33' will be compressed. For higher compression loads, this yields a stiffer compression characteristic of the spring core 2.
As illustrated, the pocketed spring elements 21 are interleaved with the pocketed spring elements 31'. In the illustrated example, this interleaving is based on an interleaving pattern where the pocketed spring elements 21 alternate in a one-to-one sequence with the pocketed spring elements 31'. However, other interleaving patterns could be used as well.
Fig. 5 shows an example of how the pocketed spring elements 21, 31' could be distributed in a plane defined by the width direction and the length direction of the spring core 2. In the illustration of Fig. 5, open circles denote positions of the pocketed spring elements 21 with the higher coil springs 23, and dotted circles denote positions of the pocketed spring elements 31' with the lower foam springs 33'. In an uncompressed state of the spring core 2, the upper ends of the pocketed spring elements 21 with the higher coil springs 23 define a substantially planar upper surface of spring core 2. Like in the example of Fig. 3, the spring core 2 includes multiple sections 11, 12, 13, 14, 15, which have different distributions of the pocketed spring elements 21, 31', e.g., corresponding to head section, shoulder section, middle section, leg section, and feet section, respectively. Also in this example, the spring core 2 has a symmetrical configuration in which the section 11 is similar to the section 15 and the section 12 is similar to the section 15. However, it is noted that also configurations could be used where the sections 11, 12, 13, 14, 15 each have a different configuration.
In the example of Fig. 5, the sections 11 and 15 include only the pocketed spring elements 21 with the higher coil springs 23. In this way, these sections can be provided with a good stability. The sections 12, 13, and 14 include both the pocketed spring elements 21 with the higher coil springs 23 and the pocketed spring elements 31' with the lower foam springs 33'. In this way, the sections 12, 13, and 14 may be provided with a softer and less elastic compression characteristic than the sections 11 and 15. If the spring core 2 is compressed in the sections 12, 13, or 14, initially only the higher coil springs 23 are compressed. Because in the sections 12, 13, and 14 the number of the coil springs 23 per unit area is less than in the sections 11, 15, the spring core 2 exhibits a softer compression characteristic than in the sections 11 and 15. For higher compression loads, also the lower foam springs 33' in the sections 12, 13, 14, of the spring core 2 are compressed, and the compression characteristic becomes stiffer. In the sections 12 and 14, the relative proportion of the pocketed spring elements 31' with the foam springs 33' is higher than in the section 13. In this way, it can be achieved that the section 13 exhibits a softer and less elastic compression characteristic than the sections 12 and 14.
In some cases, it may also be beneficial to combine coil springs of different heights and/or to combine foam springs of different heights. Fig. 6 illustrates a corresponding example of pocketed spring elements 21', 21 and 31.
Also in the example of Fig. 6, each pocketed spring element 21, 21', 31 is formed of a pocket 22, 22', 32 and a spring 23, 23', 33 enclosed within the pocket 22, 22', 32, and the pockets 22, 22', 32 may be formed from one or more fabric layers, typically a non-woven fabric material, such as a non-woven polypropylene based fabric. In the case of the pocketed spring elements 21, 21', the pocket 22, 22' encloses a coil spring 23, 23'. An interior portion of the coil spring 23, 23' is hollow. In the case of the pocketed spring elements 31, the pocket 32 encloses a foam spring. The coil springs 23, 23' and the foam springs 33 are compressible in a height direction H, which is perpendicular to the width and length directions of the pocket spring core 2. The pocketed spring elements 21, 21', 31 are illustrated as being part of the same string and separated by seams 40. The coil springs 23' of the pocketed spring elements 21', and also the corresponding pockets 22', have a lower height than the coil springs 23 of the pocketed spring elements 21 and than the foam springs 33 of the pocketed spring elements 31. The coil springs 23 of the pocketed spring elements 21, and also the corresponding pockets 22, in turn have the same height as the foam springs 33 of the pocketed spring elements 31. Accordingly, when starting to compress the mattress 1 in an area which includes the pocketed spring elements 21' and 31, initially only the foam springs 33 are compressed. Only when the foam springs 33 are compressed so far that they have the same height as the coil springs 23', also the coil springs 23' will be compressed. For higher compression loads, this yields a stiffer compression characteristic of the spring core 2. Similarly, when starting to compress the mattress 1 in an area which includes the pocketed spring elements 21' and 21, initially only the coil springs 23 are compressed. Only when the coil springs 23 are compressed so far that they have the same height as the coil springs 23', also the coil springs 23' will be compressed. Again, this allows for achieving stiffer compression characteristic at higher compression loads.
As illustrated, the pocketed spring elements 21' are interleaved with the pocketed spring elements 31'. This interleaving may be based on an interleaving pattern where the pocketed spring elements 21 alternate in a one-to-one sequence with the pocketed spring elements 31'. However, other interleaving patterns could be used as well. As further illustrated, also the pocketed spring elements 21 could be interleaved with the pocketed spring elements 21' and 31. However, rather than interleaving the pocketed spring elements 21, 21', and 31 in the same string, it would also be possible to interleave the pocketed spring elements 21', and 31 in the same string, and arrange the pocketed spring elements 21 in another string. The latter option may facilitate production of the strings, because only one type of coil spring needs to be used in the same string. Fig. 7 shows a corresponding example of how the pocketed spring elements 21, 21' 31' could be distributed in a plane defined by the width direction and the length direction of the spring core 2.
In the illustration of Fig. 7, open circles denote positions of the pocketed spring elements 21 with the higher coil springs 23, and dotted circles denote positions of the pocketed spring elements 31 with the higher foam springs 33. Hatched circles denote positions of the pocketed spring elements 21' with the lower coil springs 23'. In an uncompressed state of the spring core 2, the upper ends of the pocketed spring elements 21 with the higher coil springs 23 and the pocketed spring elements 31 with the higher foam springs 33 define a substantially planar upper surface of the spring core 2. Like in the examples of Fig. 3 and 5, the spring core 2 includes multiple sections 11, 12, 13, 14, 15, which have different distributions of the pocketed spring elements 21, 21', 31, e.g., corresponding to head section, shoulder section, middle section, leg section, and feet section, respectively. Also in this example, the spring core 2 has a symmetrical configuration in which the section 11 is similar to the section 15 and the section 12 is similar to the section 15. However, it is noted that also configurations could be used where the sections 11, 12, 13, 14, 15 each have a different configuration.
In the example of Fig. 7, the sections 11 and 15 include only the pocketed spring elements 21 with the higher coil springs 23. In this way, these sections can be provided with a good stability. The sections 12, 13, and 14 include both the pocketed spring elements 21' with the lower coil springs 23' and the pocketed spring elements 31 with the higher foam springs 33. In this way, the sections 12, 13, and 14 may be provided with a softer characteristic than the sections 11 and 15. If the spring core 2 is compressed in the sections 12, 13, or 14, initially only the higher foam springs 33 are compressed. Because in the sections 12, 13, and 14 the number of the foam springs 33 per unit area is less than the number of the coil springs 23 per unit area in the sections 11, 15, the spring core 2 typically exhibits a softer characteristic than in the sections 11 and 15. Further, the compression characteristic will typically also differ due to the difference in spring type. For example, the foam springs 33 could cause a less elastic compression characteristic. For higher compression loads, also the lower coil springs 23' in the sections 12, 13, 14, of the spring core 2 are compressed, and the compression characteristic becomes stiffer. In the sections 12 and 14, the relative proportion of the pocketed spring elements 31 with the foam springs 33 is higher than in the section 13. In this way, it can be achieved that the section 13 exhibits a softer and less elastic compression characteristic than the sections 12 and 14.
It is noted that while the examples of Fig. 6 and 7 refer to a scenario where the spring core 2 includes coil springs 23, 23' of different height, it would also be possible to alternatively or additionally use foam springs of different height, e.g., by also using the pocketed spring elements 31' with the lower foam springs as explained in connection with Fig. 3 and 4.
In the examples of Figs. 2 to 7, the pocket 22, 22' of the pocketed spring elements 21, 21' includes only the respective coil spring 23, 23', and the pocket 32, 32' of the pocketed spring elements 31, 31' includes only the respective foam spring 33, 33'. However, in some cases also both types of spring could be enclosed in the same pocket. Specifically, a hybrid spring formed of both a coil spring and a foam spring may be used in place of at least some of the coil springs of the above examples. Fig. 8 illustrates a corresponding example of pocketed spring elements 21, 31 and 51 which may be used in the spring core 2.
As illustrated in Fig. 8, each of the pocketed spring elements 21 is formed of a pocket 22 and a coil spring 23 enclosed within the pocket 22, each of the pocketed spring elements 31 is formed of a pocket 32 and a foam spring 33 enclosed within the pocket 32, and each of the pocketed spring elements 51 is formed of a pocket 52 and a coil spring 53 and a foam spring 54, which are both enclosed in the pocket 52. The foam spring 54 has a cylindrical shape and is included in an interior portion of the coil spring 53. In some implantations, the foam spring 54 may freely move within the coil spring 53. The ability of the foam spring 54 to freely move within the interior of the coil spring may be used to enable self-adjustment of the spring core 2 to be operable regardless of which side of the spring core 2 is facing upwards. This may for example be useful when incorporating the spring core into a double-sided mattress.
As mentioned above, the pockets 22, 32, 52 may be formed from one or more fabric layers, typically a non-woven fabric material, such as a non-woven polypropylene based fabric. The coil springs 21, 53 and the foam springs 33, 54 are compressible in a height direction H, which is perpendicular to the width and length directions of the pocket spring core 2. The pocketed spring elements 21, 31, 51 are illustrated as being part of the same string and separated by seams 40.
In the illustrated example, the foam springs 54 of the pocketed spring elements 51 have a lower height than the coil springs 53 of the pocketed spring elements 51. Accordingly, when starting to compress the mattress 1 in an area which includes the pocketed spring elements 51, initially only the coil springs 53 are compressed. Only when the coil springs 53 are compressed so far that they have the same height as the foam springs 54, also the foam springs 54 will be compressed. For higher compression loads, this yields a stiffer compression characteristic of the spring core 2. However, it is noted that in some implementations, the coil springs 53 and the foam springs 54 of the pocketed spring elements 51 could also have the same height.
As illustrated, the pocketed spring elements 31 are interleaved with the pocketed spring elements 51. This interleaving may be based on an interleaving pattern where the pocketed spring elements 31 alternate in a one-to-one sequence with the pocketed spring elements 51. However, other interleaving patterns could be used as well. As further illustrated, also the pocketed spring elements 21 could be interleaved with the pocketed spring elements 31 and 51. However, rather than interleaving the pocketed spring elements 21, 31, and 51 in the same string, it would also be possible to interleave the pocketed spring elements 31 and 51 in the same string, and arrange the pocketed spring elements 21 in another string. The latter option may facilitate production of the strings, because only one type of coil spring needs to be used in the same string. Fig. 9 shows a corresponding example of how the pocketed spring elements 21, 31, 51 could be distributed in a plane defined by the width direction and the length direction of the spring core 2.
In the illustration of Fig. 9, open circles denote positions of the pocketed spring elements 21 with the coil springs 23, and dotted circles denote positions of the pocketed spring elements 31 with the foam springs 33. Hatched circles denote positions of the pocketed spring elements 51 with the coil springs 53 and foam springs 54. In an uncompressed state of the spring core 2, the upper ends of the pocketed spring elements 21, 31, and 51 define a substantially planar upper surface of the spring core 2. Like in the examples of Fig. 3, 5, and 7, the spring core 2 includes multiple sections 11, 12, 13, 14, 15, which have different distributions of the pocketed spring elements 21, 31, 51, e.g., corresponding to head section, shoulder section, middle section, leg section, and feet section, respectively. Also in this example, the spring core 2 has a symmetrical configuration in which the section 11 is similar to the section 15 and the section 12 is similar to the section 15. However, it is noted that also configurations could be used where the sections 11, 12, 13, 14, 15 each have a different configuration.
In the example of Fig. 9, the sections 11 and 15 include only the pocketed spring elements 21 with the coil springs 23. In this way, these sections can be provided with a good stability. The sections 12, 13, and 14 include both the pocketed spring elements 31 with the foam springs 33 and the pocketed spring elements 51 with the higher coil springs 53 and the lower foam springs 54. In this way, the sections 12, 13, and 14 may be provided with a softer characteristic than the sections 11 and 15. If the spring core 2 is compressed in the sections 12, 13, or 14, initially only the higher coil springs 53 and the foam springs 33 are compressed. Due to a softer and less elastic compression characteristic of the foam springs 33 as compared to the coil springs 23, the spring core 2 may exhibit a softer compression characteristic than in the sections 11 and 15. For higher compression loads, also the lower foam springs 54 in the sections 12, 13, 14, of the spring core 2 are compressed, and the compression characteristic becomes stiffer. In the sections 12 and 14, the relative proportion of the pocketed spring elements 31 with the foam springs 33 is higher than in the section 13. In this way, it can be achieved that the section 13 exhibits a softer and less elastic compression characteristic than the sections 12 and 14.
In some scenarios, at least some of the foam springs could also be enclosed in an individual pocket which is inserted together with the foam spring into an outer pocket. A corresponding example is illustrated in Fig. 10. The example of Fig. 10 is similar to that of Fig. 8. However, the foam springs 33 are enclosed in a further pocket 35 which is inserted together with the foam spring 33 into the pocket 32. The pocket 35 may thus be regarded as an inner pocket, and the pocket 32 may be regarded as an outer pocket. During manufacture or usage of the spring core 2, the inner pocket 35 may help to reduce or avoid friction between the foam spring 33 and the outer pocket 32. Similarly, the foam springs 54 are enclosed in a further pocket 55 which is inserted together with the foam spring 54 into the pocket 22 and the into coil spring 53. Accordingly, also the pocket 55 may be regarded as an inner pocket, and the pocket 22 may be regarded as an outer pocket. During manufacture or usage of the spring core 2, the inner pocket 55 may help to reduce or avoid friction between the foam spring 54 and the coil spring 53.
It is noted that inner pockets as illustrated in the example of Fig. 10 may be used in various ways. For example, inner pockets could be used for the foam springs 54, but not for the foam springs 33. Further, inner pockets could be used for only a subset of the foam springs 54 and/or a subset of the foam springs 33. Further, inner pockets could also be used for some or all of the foam springs 33, 33' in the examples of Figs. 2 to 7.
Fig. 11 shows a flowchart for illustrating a spring core manufacturing process which may be used to manufacture a spring core as described above, e.g., the spring core 2. That is to say, the method may be used to manufacture a spring core including first pocketed spring elements, each formed of a pocket and at least a coil spring enclosed in the pocket, such as the above-mentioned pocketed spring elements 21, 21', and 51, and second pocketed spring elements, each formed of a pocket and a foam spring enclosed in the pocket, such as the above-mentioned pocketed spring elements 31, 31'.
At step 1110, coil springs are provided, such as the above-mentioned coil springs 23, 23', or 53. The coil springs may be formed of a metal wire, e.g., of steel wire. In some scenarios, the coil springs may have different heights.
At step 1120, the coil springs are each enclosed in a respective pocket, such as the above-mentioned pockets 22, 22', 52. As a result, the first pocketed spring elements are obtained. The pockets may be formed of one or more fabric layers, e.g., a non-woven fabric. The pockets may be formed by welding the fabric layer(s). In some cases, also a foam spring may be enclosed together with the coil spring in the pocket, e.g., as explained for the pocketed spring elements 51, which include the foam spring 54 in addition to the coil spring 53.
At step 1130, foam springs are provided, such as the above-mentioned foam springs 33, 33. The foam springs may be formed as foam cylinders or pegs. The foam springs may be formed of various foam materials, e.g., a flexible polyurethane foam, a visco-elastic foam, a latex rubber foam, or a memory foam. In some scenarios, the foam springs may have different heights. Further, the foam springs could differ with respect to their foam material. For example, some of the foam springs could be formed of a memory foam, while others of the foam springs could be formed of a flexible polyurethane foam.
At step 1140, the foam springs are each enclosed in a respective pocket, such as the above-mentioned pockets 32, 32'. As a result, the second pocketed spring elements are obtained. The pockets may be formed of one or more fabric layers, e.g., a non-woven fabric. The pockets may be formed by welding the fabric layer(s).
It is noted that the enclosing processes of steps 1120 and 1140 may actually be combined, e.g., in a process which forms strings of pocketed spring elements, in which the above-mentioned first pocketed spring elements and the above-mentioned second pocketed spring elements are interleaved.
At step 1150, the first pocketed spring elements and the second pocketed spring elements are joined to form the spring core. This may for example involve joining strings of pocketed spring elements which include the first pocketed spring elements and the second pocketed spring elements. The first pocketed spring elements and the second pocketed spring elements may for example be joined by gluing, welding, or some other assembly process.
It is noted that the embodiments and examples described above are susceptible to various modifications. For example, the pocketed spring elements of different examples may be combined in the same spring core. Further, a wide variety of coil springs or foam springs may be used, without limitation to the illustrated. For example, in addition or as an alternative to cylindrical coil springs, also barrel-shaped coil springs could be used. Similarly, also the foam springs do not need to be cylindrical, but could also be cuboid shaped, barrel shaped, or cone shaped. Still further, the dimensions of the springs may be selected in various ways. For example if a foam spring is inserted into a spring coil, like in the example of Fig. 8, the outer diameter of the foam spring may match the inner diameter of the coil spring. However, the outer diameter of the foam spring could also be smaller than the inner diameter of the coil spring. Similarly, if a foam spring enclosed in an inner pocket is inserted into a spring coil, like in the example of Fig. 10, the outer diameter of the inner pocket enclosing the foam spring may match the inner diameter of the coil spring. However, the outer diameter of the inner pocket enclosing inner pocket enclosing the foam spring could also be smaller than the inner diameter of the coil spring. Similarly, if a foam spring enclosed in an inner pocket is inserted into an outer pocket, like in the example of Fig. 10, the outer diameter of the inner pocket enclosing the foam spring may match the inner diameter of the outer pocket. However, the outer diameter of the inner pocket enclosing the foam spring could also be smaller by some margin than the inner diameter of the outer pocket. Further, in some cases the height of the inner pocket enclosing the foam spring may match the inner height of the outer pocket while in other cases the height of the inner pocket enclosing the foam spring could be smaller by some margin than the inner height of the outer pocket. Further, the illustrated spring cores could include various additional pocketed spring elements.
Further, it is to be understood that the configurations of different sections as illustrated in Figs. 3, 5, 7, and 9 are exemplary and that other configurations of sections are possible as well. For example, in addition or alternative to using different sections arranged along the length direction, like in Figs. 3, 5, 7, and 9, also one or more different sections could be arranged along the width direction. Further, one section could extend around another section. For example, instead of the sections 11 and 15 in the examples of Figs. 3, 5, 7, and 9, one section 11' formed of the spring elements 21 could extend along all four edges of the spring unit 2 and enclose the sections 12, 13, and 14, which may have similar distributions of spring elements as in the examples of Figs. 3, 5, 7, and 9. A corresponding example is illustrated in Fig. 12.
Further, while the examples explained the spring core is part of a mattress, it is noted that the same or similar spring cores could also be used in various other kinds of bedding or seating products, such as in sofas or seats, e.g., as part of a sofa cushion or seat cushion.

Claims

A pocket spring core (2), comprising:
a plurality of first pocketed spring elements (21; 21'; 51), the first pocketed spring elements (21; 21'; 51) each being formed of a pocket (22; 22'; 52) and at least a coil spring (23; 23'; 53) enclosed in the pocket (22; 22'; 52); and

a plurality of second pocketed spring elements (31; 31'), the second pocketed spring elements (31; 31') each being formed of a pocket (32; 32') and a foam spring (33; 33') enclosed in the pocket (32).
The pocket spring core (2) of claim 1,
wherein in an uncompressed state the coil springs (23; 23'; 53) of the first pocketed spring elements (21; 21'; 51) have a different height than the foam springs (33; 33') of the second pocketed spring elements (31; 31').
The pocket spring core (2) of claim 1 or 2,
wherein in an uncompressed state the coil springs (23; 23'; 53) of the first pocketed spring elements (21; 21'; 51) have different heights.
The pocket spring core (2) according to any one of the preceding claims,
wherein in an uncompressed state the foam springs (33; 33') of the second pocketed spring elements (31; 31') have different heights.
The pocket spring core (2) according to any one of the preceding claims,
wherein the coil springs (23; 23'; 53) of the first pocketed spring elements (21; 53) comprise:
- first coil springs (23), which in an uncompressed state have the same height as at least some of the foam springs (33; 33') of the second pocketed spring elements (31; 31'), and

- second coil springs (23') which in an uncompressed state have a different height than at least some of the foam springs (33; 33') of the second pocketed spring elements (31; 31').
The pocket spring core (2) according to any one of the preceding claims,
wherein the foam springs (33; 33') of the second pocketed spring elements (31; 31') comprise:
- first foam springs, which in an uncompressed state have the same height as at least some of the coil springs (23; 23'; 53) of the first pocketed spring elements (21; 21'; 51) and

- second foam springs which in an uncompressed state have a different height than at least some of the coil springs (23; 23'; 53) of the first pocketed spring elements (21; 53).
The pocket spring core (2) according to any one of the preceding claims,
wherein for at least some of the first pocketed spring elements (51) the pocket (52) encloses the coil spring (53) and a foam spring (54).
The pocket spring core (2) according to claim 7,
wherein in an uncompressed state the coil spring (53) and the foam spring (54) of the first pocketed spring element (51) have different heights.
The pocket spring core (2) according to claim 8,
wherein the foam spring (54) is moveably inserted in the coil spring (53).
The pocket spring core (2) according to any one of the preceding claims,
wherein the pocket spring core (2) has multiple sections (11, 11', 12, 13, 14, 15); and
wherein at least some of the multiple sections (11, 11', 12, 13, 14, 15) differ with respect to a distribution of the first pocketed spring elements (21; 21'; 51) and the second pocketed spring elements (31; 31').
The pocket spring core (2) according to any one of the preceding claims,
wherein at least some of the first pocketed spring elements (21; 21'; 51) are interleaved between at least some of the second pocketed spring elements (31; 31'), and/or
wherein at least some of the second pocketed spring elements (31; 31') are interleaved between at least some of the first pocketed spring elements (21; 21'; 51).
The pocket spring core (2) according to any one of the preceding claims,
wherein the foam springs (33; 33') of at least some of the second pocketed spring elements (31; 31') are formed of memory foam.
The pocket spring core (2) according to any one of the preceding claims,
wherein the coil springs (23; 23'; 53) of at least some of the first pocketed spring elements (21; 21'; 51) are formed of a metal wire.
A bedding or seating product (1),
wherein the bedding or seating product (1) comprises a spring core according to any one of the preceding claims.
A method of manufacturing a pocket spring core (2) according to any one of claims 1 to 13, the method comprising:
- providing a plurality of coil springs (23; 23'; 53);

- enclosing each of the coil springs (23; 23'; 53) in a respective pocket (22; 22'; 52) to form the first pocketed spring elements (21; 21'; 51);

- providing a plurality of foam springs (33; 33');

- enclosing each of the foam springs (33; 33') in a respective pocket (32; 32') to form the second pocketed spring elements (31; 31'); and

- joining the first pocketed spring elements (21; 21'; 51) and the second pocketed spring elements (31; 31') to the pocket spring core (2).