Individually pocketed coil springs with cushioning pads, and pocket spring mattresses with such pocketed coil springs

Abstract

An individually pocketed coil spring for use in a bedding or seating product, is disclosed, as well as pocket spring mattresses including such pocketed coil springs. The individually pocketed coil spring include: a coil spring having an upper end and a lower end; a casing forming a pocket enclosing said coil spring; and a cushioning pad located above said upper end of the coil spring. The casing provides a first compartment enclosing the coil spring, and a second compartment enclosing the cushioning pad. The first and second compartments are separated from each other.

Claims

1. A pocket spring mattress for use in a bedding or seating product, comprising a plurality of parallel strings of individually pocketed coil springs, each individually pocketed coil spring comprising: a coil spring having an upper end and a lower end; a casing forming a pocket enclosing said coil spring; and a cushioning pad located above said upper end of the coil spring; wherein the casing provides a first compartment enclosing the coil spring, and a second compartment enclosing the cushioning pad, said first and second compartment being separated from each other, wherein the casing comprises a first piece of fabric forming said first compartment, and a second piece of fabric forming said second compartment, said second piece of fabric being connected to an exterior of said first piece of fabric by a surface joint, wherein the first piece of fabric entirely encloses the coil spring, and the second piece of fabric is arranged to partly enclose the first compartment, and to be secured to the first piece of fabric, and wherein the cushioning pads of said individually pocketed coil springs have a square configuration, and are dimensioned to cover essentially the whole upper surface of the mattress.

2. The pocket spring mattress of claim 1, wherein the second piece of fabric is secured to the first piece of fabric along a few transverse connection lines extending parallel to the longitudinal direction of the coil spring, said connecting lines comprising surface joints.

3. The pocket spring mattress of claim 2, wherein the surface joint is an adhesive or a weld.

4. The pocket spring mattress of claim 1, wherein the coil spring comprises an upper end turn, a lower end turn and a plurality of convolutions between said end turns.

5. The pocket spring mattress of claim 1, wherein the individually pocketed coil springs further comprises a second cushioning pad located below said lower end of said coil spring, said second cushioning pad being arranged in a third compartment, said third compartment being separated from said first and second compartments.

6. The pocket spring mattress of claim 1, wherein the cushioning pads includes at least one piece of foam.

7. The pocket spring mattress of claim 6, wherein the at least one piece of foam is made of urethane or latex.

8. The pocket spring mattress of claim 1, wherein the cushioning pads comprises a piece of cloth secured to a piece of foam.

9. The pocket spring mattress of claim 1, wherein the casing is a weldable textile material.

10. The pocket spring mattress of claim 1, wherein each of said strings of individually pocketed coil springs comprises a plurality of aligned coil springs, the first piece of fabric surrounding said aligned coil springs, and forming said casing for each individually pocketed coil spring, said first piece of fabric being divided into a plurality of pockets by spaced transverse connecting lines, each pocket containing one of said coil springs.

11. The pocket spring mattress of claim 10, wherein said first piece of fabric further comprises at least one longitudinal connecting line extending parallel to the longitudinal direction of the string, which define said pockets together with a plurality of transverse connecting lines extending transversely to the longitudinal direction of the string.

12. The pocket spring mattress of claim 10, wherein said second piece of fabric is connected to said first piece of fabric along said spaced transverse connecting lines.

13. The pocket spring mattress of claim 1, wherein the parallel strings each comprises a plurality of interconnected pocketed coil springs, and wherein the parallel strings are arranged side by side and interconnected by surface attachment between abutting surfaces.

14. The pocket spring mattress of claim 13, wherein the surface attachment adapted to interconnect the strings comprises at least one of gluing and welding.

15. A pocket spring mattress for use in a bedding or seating product, comprising a plurality of parallel strings of individually pocketed coil springs, wherein each individually pocketed coil spring comprising: a coil spring having an upper end and a lower end; a casing forming a pocket enclosing said coil spring; and a cushioning pad located above said upper end of the coil spring; wherein the casing provides a first compartment enclosing the coil spring, and a second compartment enclosing the cushioning pad, said first and second compartment being separated from each other, wherein the casing comprises a first piece of fabric forming said first compartment, and a second piece of fabric forming said second compartment, said second piece of fabric being connected to the exterior of said first piece of fabric by a surface joint, wherein the first piece of fabric entirely encloses the coil spring, and the second piece of fabric is arranged to partly enclose the first compartment, and to be secured to the first piece of fabric.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing currently preferred embodiments of the invention.

(2) FIG. 1 shows a schematic perspective view of an embodiment of a mattress according to an embodiment of the present invention.

(3) FIG. 2 shows a cross-sectional view of an individually pocketed coil spring in accordance with a first embodiment of the present invention.

(4) FIG. 3 shows a cross-sectional view of an individually pocketed coil spring in accordance with a second embodiment of the present invention.

(5) FIG. 4 is a schematic and partly cross-sectional perspective view, illustrating various method steps for the production of the individually pocketed coil springs of FIG. 2.

(6) FIGS. 5a and 5b are schematic perspective views, illustrating various method steps for the production of the individually pocketed coil springs of FIG. 3.

(7) FIG. 6 is a schematic view illustrating a manufacturing apparatus for use in conjunction with the method illustrated in FIG. 5.

DETAILED DESCRIPTION

(8) With reference to FIGS. 1-3, there is illustrated a mattress 1 embodying the invention of this application. Although a mattress is illustrated, the present invention may be used to construct any bedding or seating product. This mattress 1 comprises a plurality of individually pocketed coil spring units 2.

(9) The mattress 1 is here formed from a plurality of parallel strips or strings 3 of individually pocketed coil spring units 2. Each string 3 of pocketed coil springs 2 preferably comprises a fabric covering or strip of fabric 31 within which there is located a row or column of aligned coil springs. Individual pockets are here formed by longitudinal connecting lines 32, extending along the strings e.g. on the top or at the middle of the strings, and by transversal connecting lines 33, extending in the axial direction of the springs. Adjacent strings of springs 3 may be secured to each other by surface attachments on adjacent surfaces, such as by gluing, ultrasonic welding, hog rings or any other means.

(10) In the above-discussed embodiments, the individually pocketed coil spring units are arranged as continuous strings, arranged side-by-side, and extending in parallel to each other, in a width or length direction of the mattress, or any other spring assembly. However, several alternative configurations are feasible. For example, the strings may occur non-linearly, in serpentine shapes or the like. Further, the individually pocketed coil spring units may be provided as single units, or shorter strings, consisting of only a few individually pocketed coil springs.

(11) As best seen in FIGS. 2 and 3, each individually pocketed coil spring unit comprises a casing 31 forming the pocket, and providing a first compartment 21 enclosing a coil spring 4, and a second compartment 22 enclosing a cushioning pad 5. The first and second compartments are separated from each other. The coil springs each has an upper end 41 and a lower end 42. The second compartment 22 is arranged above the first compartment 21, so that the cushioning pad 5 is located above the upper end 41 of the coil spring 4. Thus, the cushioning pads may hereby be maintained in place solely by being enclosed in the compartments, without the need for any additional fixation.

(12) In the above-discussed exemplary embodiments, two compartments are provided, and cushioning pads are provided only on one side of the mattress. However, it is also feasible to provide three or more compartments. For example, the individually pocketed coil spring units may comprise a compartment housing a cushioning pad both at the upper and lower ends of the coil springs. Hereby, cushioning pads will be provided at both sides of the mattress.

(13) The coil spring preferably comprises an upper end turn, a lower end turn and a plurality of convolutions between said end turns. Preferably, the coil spring comprises 2-10 convolutions, and most preferably 5-8 convolutions.

(14) Each casing/pocket contains at least one, and preferably only one, helical coil spring. The springs may have a spiral turn with a diameter of approximately 2 to 10 cm, and preferably about 6 cm. Preferably, the coil springs are barrel shaped, having upper and lower turns having a smaller diameter than the turns at the centre of the springs. However, alternatively the convolutions may all have identical diameter, or may have other variations in diameters. For example, the coil springs may be in the form of an hour-glass-shaped coil spring or any other shapes of springs.

(15) The cushioning pads may be formed by a single material, or by several different materials. For example, the cushioning pads may have a layered structure, e.g. comprising a foam center piece, an upper fabric piece and a lower fabric piece. The upper and lower fabric pieces may be glued or otherwise secured to the upper and lower surfaces of the foam center piece. Alternatively, the cushioning pad may comprise a single or multiple pieces of foam with or without any cloth pieces. The foam piece may be made of polyurethane, latex or any other conventional foam material. Alternatively, pads of cotton or any other material may be used. Pads of gel or the like may also be used, optionally enclosed in envelopes.

(16) Although the cushioning pads are illustrated as being generally square in shape, they may alternatively be any other shape or configurations, such as foam cylinders, rectangles or any other desired shape. Similarly, the height of the cushioning pads may be varied as deemed appropriate and suitable for any particular application.

(17) Different cushioning pads and/or coil springs may also be used in different individually pocketed coil spring units, in order to provide various properties in different parts of the mattress. This may e.g. be used to form zones having different properties in the mattress.

(18) As illustrated in FIG. 1, the mattress 1 has a generally planar top surface, formed by the individually resilient cushioning pads.

(19) The compartments in the casing may be provided in various ways, and two exemplary embodiments are illustrated in FIGS. 2 and 3.

(20) In the embodiment of FIG. 2, the first compartment and the second compartment are formed by a single piece of fabric. The casing material is here arrange in an S-shape to form the separate compartments, in a way similar to the disclosure in U.S. Pat. No. 6,397,418 by the same applicant, said document hereby being incorporated in its entirety by reference. A first part of the casing material forms the first compartment 21, and the compartment is closed by the longitudinal connecting line 32, being arranged at the side of the unit. Part of the material extends past the longitudinal connecting line 32, and is brought back towards the other side of the unit, and connected to the side of the first compartment 21 by means of a second longitudinal connecting line 34. Hereby, the second compartment 22 is formed on top of the first compartment 21.

(21) In an alternative embodiment, illustrated in FIG. 3, a first piece of casing material is used to form the first compartment, and a second piece of fabric forms the second compartment. Thus, in this embodiment the first piece of casing material forms conventional pockets for pocketing coil springs, and the second piece of fabric forms the additional second compartment for housing of the cushioning pad.

(22) The first piece of fabric hereby preferably entirely encloses the coil spring, and the second piece of fabric is arranged to be placed over the top of the first compartment, partly enclosing the first compartment, and to be secured to the first piece of fabric.

(23) The second piece of fabric may be connected to the first compartment by means of longitudinal connection lines 35, and/or by means of transverse connection lines. In a preferred embodiment, the second piece of fabric is secured to the first piece of fabric only along transverse connection lines extending parallel to the longitudinal direction of the coil spring. These transverse connection lines may coincide with the transverse connection lines 33 separating the pockets housing the coil springs, and may be formed simultaneously with and/or by these transverse connection lines 33. Hereby, connection of the second piece of fabric may easily be incorporated in the conventional pocket spring manufacturing process.

(24) The above-discussed connection lines, arranged longitudinally or transversely, preferably consist of a surface joint, such an adhesive, a weld or the like. The connection lines may be arranged as continuous straight or non-straight lines, or as discontinuous lines, comprising dots or the like arranged along a line.

(25) In FIG. 4, there is shown a schematic production method and production device for producing a continuous string of individually pocketed coil springs of the type discussed above with reference to FIG. 2.

(26) First, a continuous fabric is folded or wrapped to form two plies of fabric connected to each other at one side. Alternatively, two separate plies of fabric may be connected to each other at one side. Compressed coil springs are inserted between the plies, as is shown at position A. Thereafter, the plies are connected to each other at the open end, along a longitudinal connection line 32, thereby encircling the inserted coil spring. In this position, the coil springs may be turned, if inserted in a rotated position, and allowed to expand. One of the plies extends past the connection line 32. Thereafter, a cushioning pad 5 is arranged on top of the enclosed coil spring. This stage is shown at position B. The extended ply is thereafter wrapped over the cushioning pad, as is shown at position C.

(27) The wrapped ply may be connected at the other side along a longitudinal connection line 34. However, it is also feasible to connect the wrapped over ply only by transverse connection lines. This state is illustrated in Fig D.

(28) Thereafter, the transverse connection lines 33 are formed, dividing the string into separate pockets, so that each individual unit comprises two compartments, and so that each compartment comprises only one coil spring or only one cushioning pad. This state is illustrated in Fig E. The transverse connection lines 33 here serve the double purposes of both separating the compartments housing the coil springs from each other, and connecting the material forming the second compartments to the first compartments.

(29) The transverse connection lines 33 may e.g. be formed by welding. E.g. it is possible to use a heating element 6, and preferably an ultrasonic heating element, which is moveable towards the string, thereby applying heat to form weld at desired positions. However, other ways of forming welds are also feasible, as is well known to the skilled addressee.

(30) In FIG. 5, there is shown a schematic production method and production device for producing a continuous string of individually pocketed coil springs of the type discussed above with reference to FIG. 3.

(31) First, a continuous fabric is folded or wrapped to form two plies of fabric connected to each other at one side. Alternatively, two separate plies of fabric may be connected to each other at one side. Compressed coil springs are inserted between the plies. Thereafter, the plies are connected to each other at the open end, along a longitudinal connection line 32, thereby encircling the inserted coil spring. In this position, the coil springs may be turned, if inserted in a rotated position, and allowed to expand. This state is shown schematically in FIG. 5a.

(32) Thereafter, a second piece of fabric is provided above the coil springs, and cushioning pads are provided between the enclosed coil springs and the second piece of fabric. This is also shown schematically in FIG. 5a.

(33) The second piece of fabric is wrapped over the cushioning pads and over the top of the enclosed coil springs. Thereafter, the transverse connection lines 33 are formed, dividing the string into separate pockets, so that each individual unit comprises two compartments, and so that each compartment comprises only one coil spring or only one cushioning pad. The transverse connection lines 33 here serve the double purposes of both separating the compartments housing the coil springs from each other, and connecting the second material forming the second compartments to the first compartments. This is illustrated schematically in FIG. 5b.

(34) As in the previous example, the transverse connection lines 33 may e.g. be formed by welding. E.g. it is possible to use a heating element, such as an ultrasonic weld equipment, which is moveable towards the string, thereby applying heat to form weld at desired positions. However, other ways of forming welds are also feasible, as is well known to the skilled addressee.

(35) Each transverse line of attachment 33 preferably extends generally from an upper surface of the string of springs to a lower surface of the string of springs, and thus extends approximately the entire height of the string of springs. However, the transverse lines of attachment 33 may be any desired length. In addition, multiple transverse lines of attachment 33 may exist between adjacent pockets.

(36) The first and second piece of fabric may be provided continuously and simultaneously, as is shown schematically in FIG. 6. Thus, the first fabric may be provided from a first roll 61 of material, and the second fabric may be provided from a second roll 62 of material. The fabrics are then guided into a manufacturing apparatus 63 where the materials are formed into pockets each having two compartments, in the way discussed above. The cushioning pads are preferably provided between the sheets of fabric. For example, pre-cut cushioning pads may be provided in a magazine 64 or other form of supply, and be dispensed between the two sheets of fabric by a dispenser 65 or the like. Alternatively, the cushioning pads may be provided as a continuous string, which is cut into suitable lengths immediately prior to being dispensed.

(37) By this arrangement, correct positioning of the cushioning pads is enabled in a very convenient and efficient manner. The cushioning pads will be moved along with the sheets of fabric during the entire manufacturing process, and will be held and maintained in a correct position by the friction of the sheets.

(38) Thus, in both the above-discussed methods, it is possible to use a conventional manufacturing process for making pocket mattresses, and to simply add a separate compartment on top of each pocket unit to incorporate the cushioning pad. Hereby, the present invention lends itself very well to automated and cost-efficient manufacturing, and it is also relatively simple to incorporate the additional steps of providing a separate compartment for the cushioning pad and to insert such cushioning pads into said compartments in previously known and used manufacturing processes.

(39) To form a pocket spring mattress for use in a bedding or seating product, comprising a plurality of parallel strings of individually pocketed coil springs, strings formed as discussed above may be connected together, side-by-side, e.g. by providing surface attachments between adjacent surfaces. For example, it is possible to use glue, Velcro, ultrasonic welding, clamps or the like to connect such strings.

(40) The assembly of parallel strings of springs may optionally be joined to upper and lower generally rectangular border wires located in the top and bottom planes of the bedding or seating product. In order to complete the bedding or seating product of the present invention, a covering pad may optionally be placed over the spring assembly and an upholstered covering placed above the pocket spring mattress.

(41) Each string of springs preferably comprises a row of individual coil springs, a strip of fabric surrounding the coil springs and a plurality of cushioning pads placed on top of the coil springs outside the fabric enclosing the coil springs. The strip of fabric in each string is divided into a plurality of pockets by spaced transverse lines of attachment. Each pocket contains one the coil springs, and an additional compartment above each coil spring encloses at least one cushioning pad located above the coil spring. An additional cushioning pad or pads may be located below the coil spring in an additional compartment.

(42) The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For instance, more than one cushioning pad may be arranged in each individually pocketed coil spring unit. Further, the individually pocketed coil spring units may be assembled in various ways, in the form of parallel strings, strings arranged in various patterns, or by separate individual units. Further, the separate compartments of the units may be formed in various ways, e.g. by a single piece of fabric, or by two or more separate pieces of fabric. Such and other modifications of the pocket units and the mattress formed by such units form part of the present invention, as it is defined in appended claims.