1. Field of the Invention
The present invention relates to a spring mattress having two superposed layers of springs, which springs are enclosed in covers, and to a method of manufacturing a mattress of this kind.
2. Description of Background Art
One common technique for manufacturing spring mattresses is known as the xe2x80x9cpocket techniquexe2x80x9d. According to this technique, the springs are enclosed in pockets, i.e., they are enclosed individually by a covering material. Owing to this arrangement, the springs become individually resilient, such that each spring may flex separately without affecting neighboring springs, which increases the user""s comfort, since the load will be distributed more evenly across the surface that receives the load.
In order to further enhance comfort, two super-posed layers of pocket springs are used in some cases, i.e., a structure, which in principle consists of two joined-together pocket spring mattresses. In this type of mattress the load exerted on the mattress by the user is distributed further, and the mattress is felt as more comfortable.
One problem found in this type of mattresses is, however, that they are complex and time-consuming to manufacture and in addition, much material is required, since in principle it is necessary not only to manufacture two conventional pocket spring mattresses but also to join the two mattresses together.
A further problem encountered in this type of mattresses is that only the springs in the uppermost layer are individually resilient. Because of the material of the covers, the force exerted on the lower-layer springs by the lower parts of the loaded upper-layer springs is distributed over the upper layer, and from there it is distributed over several springs in the lower layer. This detracts from the individual resilience of the bottom-layer springs and consequently this layer contributes only marginally to the comfort of the mattress.
One object of the present invention thus is to provide a spring mattress of the kind defined in the introduction hereto, and to suggest a method of manufacturing said mattress, wherein the disadvantages referred to above are completely or at least partly eliminated.
This object is achieved by a spring mattress and a manufacturing method therefor as defined in the appended claims.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood from the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.