WO2007013855A1

WO2007013855A1 - An innerspring unit

Info

Publication number: WO2007013855A1
Application number: PCT/SG2005/000349
Authority: WO
Inventors: Kai Long Tan
Original assignee: PINTAS Pte Ltd
Current assignee: PINTAS Pte Ltd
Priority date: 2005-07-28
Filing date: 2005-10-11
Publication date: 2007-02-01
Anticipated expiration: 2008-01-28
Also published as: US20080237948A1; CN101237793A; AU2005334829A1; JP2009502309A

Abstract

An improved manufacturing of innerspring unit (100) for a mattress that comprises of rows and columns of coil springs (110) connected to each other with a helical wire (120). An independent suspension namely pocket spring (170) is being installed at the center portion of the innerspring to provide additional suspension support to the heaviest part of the body namely the hip portion while in sleeping position.

Description

An Iπnerspring Unit

Field of Invention

This invention relates to a mattress structure and in particular to an improved innerspring unit for a mattress.

Background of the Invention

Conventional mattress is constructed with an innerspring unit, a top cover assembly and a bottom cover assembly. The innerspring unit includes arrays of coil springs arranged in linear rows. Each two adjacent coil springs are attached to one another at top and bottom by spring retainer elements. The top and bottom cover assemblies are each composed of multiple layers of resilient foam material and an outer layer of fabric.

Generally, an ideal mattress should provide a balance between firmness and softness. The mattress should be firm enough to provide adequate support. However, the mattress should be also soft enough that it will not be uncomfortable to the user. Thus, there is always the goal for the manufacturer to produce mattress that is a balance between these two conflicting qualities.

For a typical innerspring mattress, firmness is provided by the coil springs of the innerspring unit and softness is provided by the foam layers of the top and bottom cover assemblies. The mattress will feel firmer if the foam layer of the top cover assembly is relatively thin. This is because relatively little load will be absorbed by the top cover assembly and most of the load is absorbed by the innerspring unit. In this case, the mattress will feel firmer rather than softer. The mattress might even be termed hard. If the foam layers of the top cover assembly are thicker, more loads will be absorbed by the top cover assembly and less by the innerspring unit, and the mattress will feel softer. However, this is not desirable as certain degree of firmness is required to support the weight of the users for optimum comfort. In the conventional mattress, the structure of the innerspring units is virtually homogeneous. However, our body parts have different weight distribution at different portion in our body. When it is in sleeping posture, the hips portion is the heaviest part in our body. As a user sleeps on a conventional mattress, different force due to different weight distribution is applied onto the mattress. The force is greater at the center of the mattress, which is the location of the hips portion in sleeping position. This will cause the top surface of the mattress to conform to the contour of the human body due to different weight distribution. This subsequently will affect user comfort.

The invented innerspring structure introduces an additional resilient material into the center portion of the innerspring unit to create additional support for the extra load of the hips portion in our body while in sleeping position.

Summary of the Invention The present invention is an improved method of manufacturing an innerspring unit for a mattress, wherein the innerspring unit includes the coil springs or bonnell spring, spring retainer element namely helical wire and an independent resilient element referred to as pocket spring.

The innerspring units are typically made up of rows and columns of coil springs, each coil spring having a top and bottom planar portion. Each two adjacent coil springs are attached one to one another at top and bottom by spring retainer element namely the helical wire. The coil springs are arranged in a plurality of linear rows that are mutually parallel to the width of the mattress and are spaced apart at a predetermined distance perpendicular to the length of the mattress. A passage perpendicular to the length of the mattress is formed between two adjacent rows of coil springs.

The novelty of this invention is the insertion of an independent resilient element namely the pocket springs into the passage between two adjacent rows of the coil springs at the center of the innerspring. It is aim to provide additional suspension to the heaviest part of the body namely the hips portion while in sleeping position. Each pocket spring contains several turns of coil springs which being wrapped and sewed in compressed state to form an array of pocket spring. The height dimension of the wrapped pocket springs is just slightly lower than the height of the coil springs in relaxed state. The pocket springs is configured in such a way to facilitate the installment and to serve the function as the additional suspension unit to the innerspring.

The top and bottom cover assemblies to the innerspring are each composed of multiple layers of resilient foam material and outer layer of fabric. The resilient foam material comprises of a layer of coconut fiber, follow by a layer of Polyurethane (PU) or latex and the outer layer of fabric. The coconut fiber layer helps to prevent cupping of the mattress while the PU layer functions to increase the comfort to the user.

The top and bottom of the outer most coil springs are attached to a border wire by clipping to create the peripheral wall to the mattress. Resilient foam is installed surrounding the side of the outer most coil spring in a known manner to provide greater edge support around the entire mattress perimeter for full sleeping comfort. This in turn adds to the mattress lifetime as it eliminates soft, sagging edges.

When a user applies increasing weight to the center portion of the mattress where the pocket springs is being installed, force is applied initially to compress the foam layers of the upper cover assembly. As the load increases, it is taken up by further compressing the head of the coil spring; the head of the coil springs will then compress the installed pocket springs as well as the individual suspension of the coil spring. The pocket spring is able to provide additional suspension support to the innerspring unit. Accordingly, the mattress feels firmer in the center as compare to the condition without the pocket springs.

The invention is not restricted to the particular embodiment that has described, and that variations may be made therein without departing from the scope of the invention as defined in the appended claims and equivalent thereof. Brief Description of the Drawings

For a better understanding of the features and advantages of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings wherein there is shown and described an illustrative embodiment of the invention in which:

Figure 1 illustrates the perspective view of a configuration of the improved innerspring that forms the mattress.

Figure 2 shows the partial sectional view of the innerspring unit at the center portion where the pocket springs are installed.

Figure 3 shows the pocket spring array in one of a possible array configuration.

Detailed Description of the Preferred Embodiments

Referring now to Figure 1 of the drawing, the invented mattress structure has an innerspring unit (100) that is generally made up of rows and columns of bonnell spring or coil spring (110). Each two adjacent coil springs are attached one to another at their head (top end) (150) and barrel (bottom end) (160) by spring retainer element nameJy the helical wire (120). The coil springs (110) are arranged in a plurality of linear rows that are mutually parallel to the width (W) of the mattress and are spaced apart at a predetermined distance perpendicular to the length (L) of the mattress. A passage (130) perpendicular to the length (L) of the mattress is formed between two adjacent rows of coil springs (110).

Referring now to Figure 2, it illustrates partial sectional view of the innerspring unit

(100) at the center portion of the mattress. Each coil spring (110) has a barrel (140) of uniform diameter and containing several turns of the coil spring (110) and a head and base (both of which are partly hidden) of larger diameter than the barrel (140). The naming of the head (150) and base (160) is merely for convenience because both segments are virtually identical. The heads (150) and bases (160) of each two adjacent coil springs (110) are attached to each other by the retainer element namely the helical wire (120). The innerspring unit (100) shown in Figure 2 is in a condition in which no external force are applied to the unit. A generally rectangular passage (130) is provided between the barrels (140) of the springs (110) in each two adjacent rows of springs. The passage (130) is bounded at top and bottom by the upper and lower helical wire (120) and bounded laterally by the barrels (140) of the adjacent rows of coil spring (110).

Figure 2 also shows that at the center portion of the innerspring unit, there are arrays of pocket spring (170) which are installed in the passage (130) by pushing manually or with supporting gadgets that facilitates the installation. The primary function of the pocket spring (170) is to provide additional support to the heaviest part of the body namely the hip portion while in sleeping position. The present embodiment is not restricted to the numbers of arrays of pocket spring installed at the center portion of the innerspring.

According to Figure 3, individual spring (171) is being wrapped with appropriate material (172) in compressed state to form an array of pocket springs in continuous mode (170). The pockets can be made from a long piece of suitable cloth-like material (172) that is sewed together along its long edge (172a) to form a long open-ended tubular wrapping material. Individual springs (171) are then inserted into the wrapping material (172) and aligned with the both ends of the spring (171) pushing against the wall of the tubular wrapping material. Each spring (171) is then separated from adjacent springs by sewing perpendicularly (172b) along the wrapping material (172) to form many pockets, each of which contained an individual spring (171). When made in this way, it facilitates the installment of the pocket springs (170) at the center portion of the innerspring unit (100) later. Alternatively, the wrapping material can have precut holes (173) on them. The wrapping material is still sewed (172a, 172b) accordingly as described earlier to form pocket with holes (173). Individual spring (171) is inserted into the pockets via the holes. If needed, it is conceivable that springs (171) used may vary in hardness from one to another to form a pocket spring array (170) of varying hardness through the array. Meanwhile, Figure 2 further illustrates that innerspring unit (100) is placed on top of a lower cover assembly (L) and upper cover assembly (U) is placed on top of the innerspring unit (100). The upper (U) and lower (L) assembly are generally having the same configuration which comprises of the first layer of coconut fiber (210), follow by a layer of polyurethane (220) and the outer later of fabric (230). Latex, wool, cotton or silk can be a substitution for the polyurethane layer.

When a user applies increasing weight to the mattress, the load is first applied to compress the foam layer of the upper cover assembly (U). Further increase of weight will compress the head (150) of the coil spring (110). As the pocket springs (170) are placed just below the head (150) of the coil spring (110), this will subsequently compress the springs (171) in the wrapped material (172) as well as the suspension generated by the coil springs (110) themselves. The pocket spring (170) acts as an independent suspension unit to provide additional suspension support to the weight of the hip portion of the body while in sleeping position. Accordingly, the user will feel a more uniform suspension support throughout the mattress.

The modifications to the various aspects of the present invention described herein above are merely exemplary. It is understood that other modifications to the illustrative embodiments will readily occur to persons with ordinary skill in the art without departing from the scope and spirit of the present invention as defined by the accompanying claims.

Claims

1. An improved innerspring unit for a mattress comprising: rows and columns of coil springs wherein said coil spring are arranged in a plurality of rows of coil springs that are mutually spaced apart from adjacent said row of coil springs at a predetermined distance, whereby a passage is formed between two adjacent rows of said coil springs; and an independent resilient element is installed in said passage, wherein height of said resilient element is just slightly lower than the height of the coil springs in relaxed state.

2. An improved innerspring unit for a mattress comprising: rows and columns of coil springs wherein said coil spring are arranged in a plurality of rows of coil springs that are mutually spaced apart from adjacent said row of coil springs at a predetermined distance, whereby a passage is formed between two adjacent rows of said coil springs; and an independent resilient element is installed in said passage, wherein height of said resilient element is about the same as the height of the coil springs in relaxed state.

3. The improved inner spring unit according to claims 1 and 2, wherein said coil spring has a barrel section connecting a head portion to a base portion, said head portion and said base portion are larger than said barrel section.

4. The improved inner spring unit according to claim 3, wherein said head and base of a two adjacent said coil spring is connected by spring retainer elements.

5. The improved inner spring unit according to claims 1 and 2, wherein said resilient material is a pocket spring.

6. The improved inner spring unit according to claim 5, wherein said pocket spring has a spring that is contained in a pocket.

7. The improved inner spring unit according to claim 6, wherein said pocket is sealed with said spring contained therein.

8. The improved inner spring unit according to claim 5, wherein said array of pocket springs is sewed together to form an array of said pocket springs.

9. The improved inner spring unit according to claim 8, wherein said array of pocket springs is in linear configuration.

10. The improved inner spring unit according to claims 1 and 2, wherein said pocket spring is located at the center portion of a mattress that is made of said improved inner spring unit.