WO2014080302A1

WO2014080302A1 - A spring element for mattresses and a method for making a spring element for mattresses.

Info

Publication number: WO2014080302A1
Application number: PCT/IB2013/058993
Authority: WO
Inventors: Diano Tura
Original assignee: Flexfor S.R.L.
Priority date: 2012-11-23
Filing date: 2013-09-30
Publication date: 2014-05-30
Also published as: ITRN20120052A1; EP2922446B1; EP2922446A1

Abstract

Described is a spring element for mattresses, comprising a first helical spring (2) extending along a longitudinal axis (A) between its first end (2a) and its second end (2b), and a second helical spring (4) extending inside the first spring (2) along the longitudinal axis (A) between its first end (4a), proximal to the first end (2a) of the first spring (2), and its second end (4b) located at a predetermined axial distance from the second end (2b) of the first spring (2). The spring element also comprises a casing 5 which is deformable and at least partly tubular positioned around the first spring (2) to form a chamber (6) for containing the first (2) and the second spring (4), wherein the casing (5) has at least one neck (7) interposed between the second end (4b) of the second spring (4) and the second end (2b) of the first spring (2) for separating the chamber (6) into a first compartment (6a), containing a portion (8a) of the first spring (2) and the second spring (4), and a second compartment (6b), containing an end portion (8b) of the first spring 2.

Description

DESCRIPTION

A SPRING ELEMENT FOR MATTRESSES AND A METHOD FOR MAKING A SPRING ELEMENT FOR MATTRESSES. Technical field

This invention relates to a spring element for mattresses and a method for making a spring element for mattresses.

More specifically, this invention applies to the technical sector of products for the night-time area of a home, and in particular to the making of mattresses for beds.

Background art

In the prior art spring elements are made of the double type, that is, equipped with a first and a second spring coaxial with each other and arranged one inside the other to give the mattress a compliance which is gradual and more suitable for the needs of the user.

More specifically, the prior art spring elements have a first outer spring with a greater length and lesser rigidity, inside of which is positioned a second spring with a shorter length and greater rigidity (that is, with coils of a smaller diameter and closer together).

Disadvantageously, the difference in length between the two springs results in problems in the coaxial condition during compression of the springs.

More specifically, it is not uncommon that during compression of the first spring (with a greater length and lesser rigidity) this bends relative to its axis and interferes with the second spring, producing an unpleasant sensation for the user and an annoying noise.

To overcome this problem, both the springs have been inserted inside a bag, which only prevents the sliding between two adjacent spring elements and not between the first and the second spring of a single element.

Disclosure of the invention

In light of this, the aim of this invention is to provide a spring element for mattresses and a method for making a spring element for mattresses which overcome the above mentioned drawbacks of the above-mentioned prior art.

More specifically, the aim of this invention is to provide a spring element for mattresses which is silent and comfortable for the user, and a method for making a spring element for mattresses which is simple and inexpensive.

These aims are fully achieved by the spring element for mattresses and by the method for making the spring element for mattresses according to this invention, comprising the features described in one or more of the claims. Brief description of the drawings

These features of the invention will become more apparent from the following detailed description of a preferred, non-limiting example embodiment of it, with reference to the accompanying drawings, in which:

- Figure 1 is a perspective view of a spring element for mattresses according to this invention, with some hidden parts shown;

- Figures 2a-2c show a sequence of the steps for making the spring element of Figure 1.

Detailed description of the preferred embodiments of the invention With reference to the accompanying drawings, the numeral 1 denotes a spring element for mattresses according to this invention.

The spring element 1 is an elastic body used inside spring mattresses, to make the resting of the user comfortable. More specifically, numerous spring elements 1 are located inside the mattress, positioned in lines and columns to occupy the entire surface on which the mattress is lying.

Each spring element 1 comprises an elastic element 1a equipped with a first 2 and a second helical spring 4 extending along a longitudinal axis "A".

Each spring 2, 4 extends about the longitudinal axis "A" with a succession of first 3a and second coils 3b.

More specifically, the second spring 4 extends inside the first spring 2. In other words, each second coil 3b is positioned inside a first coil 3a of the first spring 2.

Thus, the second coils 3b each have a diameter less than the first coils 3a in which they are positioned. Preferably, the second helical spring 4 extends (inside the first spring 2) along the longitudinal axis "A" between its first end 4a and its second end 4b.

The first end 4a of the second spring 4 is proximal (preferably connected) to the first end 2a of the first spring 2. The second end 4b of the second spring 4 is, on the other hand, positioned at a predetermined distance from the second end 2b of the first spring 2.

The expression "axial distance" in this text means a distance measured along the longitudinal axis "A".

Thus, the axial extension of the first spring 2 is greater than that of the second spring 4.

Preferably, both the first 2 and the second spring 4 extend (in a helical fashion) in a substantially prismatic fashion. In other words, the diameter of two successive first coils 3a is substantially equal. Similarly, the diameter of two successive second coils 3b is also substantially equal. In the preferred embodiment, the first 2 and the second spring 4 are connected to each other (irremovably), preferably at the respective first ends 2a, 4a.

Still more preferably, the first 2 and the second spring 4 are made as a single piece, formed by a single metal wire twisted and wound on two substantially coaxial helixes (corresponding, respectively, to the first 2 and the second spring 4).

Moreover, the second spring 4 is more rigid than the second spring 2 (which yields more) to give the spring element 1 elastic properties which vary as a function of the position along the compression stroke.

In order to reduce the noise, the spring element 1 comprises a casing 5 which is deformable and at least partly tubular positioned around the first spring 2. The outer casing 5 defines a chamber 6 for containing the first 2 and the second spring 4. The outer casing 5 is preferably made from a non-self-supporting material (highly deformable) with a low friction coefficient.

The expression "non-self-supporting" is used to mean an extremely reliable material, which can be stored, for example, in rolls, and which can be easily wrapped around the first spring 2 to incorporate it.

In the preferred embodiment, the casing 5 is made using a piece 9 of the material wound around the first spring 2.

The low coefficient of friction of the material is to be assessed as a function of the noise. In effect, the main aim of the presence of the casing 5 is to reduce the noise which arises from the rubbing of two or more springs (of two adjacent spring elements 1 , or of two springs of the same spring element 1 , as described in more detail below).

In the preferred embodiment, the casing 5 (and, thus, the piece 9) is made from non-woven fabric (or similar material).

However, alternatively, the casing 5 could be made from fabric or mesh. In the preferred embodiment, the casing 5 has at least one neck 7 interposed between the second end 4b of the second spring 4 and the second end 2b of the first spring 2 for separating the chamber 6 (of the casing 5) into a first compartment 6a, containing a portion 8a of the first spring 2 and the second spring 4, and a second compartment 6b, containing an end portion 8b of the first spring 2.

Advantageously, in this way the second spring 4 is fully contained inside the first compartment 6a, whilst the end portion 8b of the first spring 2 is located solely in the second compartment 6b, preventing an excessive offset between the first 2 and the second spring 4 and, consequently, considerably reducing the noise of the element 1.

More precisely, the casing 5 (that is, the piece 9) has at least one tubular portion positioned around the first spring 2.

Preferably, the neck 7 is located between two successive first coils 3a. More precisely, a pair of lateral flaps 10, 1 of the casing 5 are joined together at an area proximal to the longitudinal axis "A" to form the neck 7. Thus, the lateral flaps 10, 11 are interposed between two successive first coils 3a and joined together close to the longitudinal axis "A".

In the preferred embodiment, the lateral flaps 10, 11 are connected by welding, preferably of the ultrasound type.

Preferably, the casing 5 has an extension along the longitudinal axis "A" less than that of the first spring 2 in a relative extended configuration, in such a way as to reduce the distance between the second end 2b of the first spring 2 and the second end of the second spring 4, facilitating the coaxial movement.

In other words, the casing 5 (that is, the piece 9 wound around the first spring 2) keeps the first spring 2 slightly preloaded, facilitating the coaxial sliding between the first spring 2 and the second spring 4.

Another object of this invention is also a method for making a spring element for mattresses, preferably of the type described above.

The method comprises preparing at least one elastic element 1a comprising the first 2 and the second helical spring 4, which extend along the longitudinal axis "A" between relative first 2a, 4a and second ends 2b, 4b. As described above, the second spring 4 extends inside the first spring 2 with the second end 4b located at a predetermined axial distance from the second end 2b of the first spring 2.

In the preferred embodiment, there is a plurality of elastic elements 1a placed side by side to form a sequence to be located inside the mattress (that is, the lines and columns described above).

There is also at least one piece 9 of a deformable coating material.

Preferably, the piece 9 is a portion of a belt or roll of non-woven fabric. Alternatively, it could be fabric or mesh.

It should be noted that the piece 9 could be designed for coating only one elastic element 1a or a plurality.

In this regard, the method comprises a step for coating the elastic element 1 a (or the elastic elements 1a) using the piece 9, in such a way that it forms a casing 5 which is deformable and at least partly tubular positioned around the elastic element 1a.

The casing 5 defines inside the chamber 6 for containing the elastic element 1a.

In the embodiment with a plurality of elastic elements 1a, each of them is wrapped by a substantially tubular portion of the piece 9.

In detail, the coating step comprises a step for winding the plurality of elastic elements 1a using the piece 9, in such a way that they are completely interposed between two parallel bands of the piece 9.

In this embodiment, the method also comprises a step for joining portions of the bands interposed between two adjacent elastic elements 1 a, in such a way as to define for each the casing 5, that is, the containment chamber 6.

Preferably, the joining step comprises moving the transversal (preferably orthogonal) portions towards the longitudinal axis "A" using pusher means. According to this invention, the method comprises a step for making a throat 7 in the casing 5 of each elastic element 1a.

The neck 7 is made by deforming the casing 5 at an area interposed between the second end 4b of the second spring 4 and the second end 2b of the first spring 2 for forming, inside the casing 5, a first compartment 6a, containing a portion 8a of the first spring 2 and the second spring 4, and a second compartment 6b, containing an end portion 8b of the first spring 2. Thus, the chamber 6 is at least partially divided in the first 6a and in the second compartment 6b.

It should be noted that the throat 7 can be defined by a joining point or by a line. Moreover, the first 6b and the second compartment 6b are in communication with each other at a peripheral area (radially) of the chamber 6.

More specifically, the step of making the neck 7 in the casing 5 comprises a sub-step of moving closer together two lateral flaps 10, 11 of the chamber 5 along a direction transversal (preferably orthogonal) to the longitudinal axis A.

With reference to the above description, the flaps 10, 11 are positioned on opposite sides of the casing 5 with respect to a mid plane containing the longitudinal axis "A".

Preferably, the sub-step of moving closer together is performed using a pair of movable pushing members S1 , S2, starting from respective positions distal from the longitudinal axis "A" (opposite to each other), moving them towards each other. The pushing members S1 , S2 are movable transversely (preferably orthogonally) to the longitudinal axis "A". More precisely, the step of making the neck 7 comprises, for forming the neck 7, a further sub-step of joining the two lateral flaps 10, 11 at an area proximal to the longitudinal axis "A".

Preferably, the joining sub-step is achieved by ultrasonic welding.

In the embodiment with a plurality of elastic elements, the step for joining the portions of piece 9 interposed between two adjacent elastic elements 1a is also performed by ultrasound welding.

Preferably, the step is performed at the same time as the step for making the neck 7.

The invention achieves the set aims and brings important advantages. In effect, the making of the neck between the two ends of the springs allows the two springs to be kept substantially coaxial, considerably reducing the noise of the spring element.

Moreover, the use of the casing to keep the two springs compact and coaxial makes the spring element high performing and at the same time inexpensive to make.

Claims

1. A spring element for mattresses, comprising:

- a first helical spring (2) extending along a longitudinal axis (A) between its first end (2a) and its second end (2b);

- a second helical spring (4) extending inside the first spring (2) along the longitudinal axis (A) between its first end (4a), proximal to the first end (2a) of the first spring (2), and its second end (4b) located at a predetermined axial distance from the second end (2b) of the first spring (2);

- a casing (5) which is deformable and at least partly tubular, positioned around the first spring (2) for forming a chamber (6) for containing the first

(2) and the second helical spring (4);

characterised in that the casing (5) has at least one narrowing (7) interposed between the second end (4b) of the second helical spring (4) and the second end (2b) of the first helical spring (2) for separating the chamber (6) into a first compartment (6a), containing a portion (8a) of the first helical spring (2) and the second helical spring (4), and a second compartment (6b), containing an end portion (8b) of the first helical spring (2).

2. The spring element according to claim , characterised in that the first helical spring (2) is formed by a succession of first coils (3a) along the longitudinal axis (A); the neck (7) being located between two first successive coils (3a).

3. The spring element according to claim 1 or 2, characterised in that the neck (7) is formed by a pair of lateral flaps (10, 11) of the casing jointed at an area proximal to the longitudinal axis (A).

4. The spring element according to claim 3, characterised in that the lateral flaps (10, 11 ) are connected by welding.

5. The spring element according to any one of the preceding claims, characterised in that the casing (5) is made from non-woven fabric.

6. The spring element according to any one of the preceding claims, characterised in that the first spring (2) and the second spring (4) are made as a single piece, formed by a single metal wire twisted on two coaxial helixes.

7. A method for making a spring element for mattresses, comprising the steps of: - preparing an elastic element (1a) comprising a first (2) and a second helical spring (4) extending along a longitudinal axis (A) between relative first (2a, 4a) and second ends (2b, 4b), wherein the second spring (4) extends inside the first spring (2) with the second end (4b) located at a predetermined axial distance from the second end (2b) of the first spring (2);

- preparing a piece (9) of deformable coating material;

- coating the elastic element (1a) using the piece (9), in such a way that the piece (9) forms a casing (5) which is deformable and at least partly tubular positioned around the elastic element (1a);

characterised in that it comprises a step of making a narrowing (7) in the casing (5) by deforming the casing (5) at an area interposed between the second end (4b) of the second spring (4) and the second end (2b) of the first spring (2) for forming, inside the casing (5), a first compartment (6a), containing a portion (8a) of the first spring (2) and the second spring (4), and a second compartment (6b), containing an end portion (8b) of the first spring (2).

8. The method according to claim 7, characterised in that the step of making a neck (7) in the casing (5) comprises a sub-step of moving closer together two lateral flaps (10, 11) of the chamber (6) along a direction transversal to the longitudinal axis (A), wherein the flaps (10, 11) are positioned on opposite sides of the chamber (6) relative to a midplane containing the longitudinal axis (A).

9. The method according to claim 8, characterised in that the step of making the neck (7) comprises, for forming the neck (7), a sub-step of joining the two lateral flaps (10, 1 1) at an area proximal to the longitudinal axis (A).

10. The method according to claim 9, characterised in that the joining step is made by ultrasonic welding.