Pocket mattress comprising openings in the casing material

Abstract

A spring mattress is disclosed, comprising a plurality of interconnected coil springs enclosed in casings, thereby forming a pocket spring mattress. For at least one of the springs, the casing portions arranged at the ends of the spring being moved towards each other, through the spring, and interconnected with the aid of connecting means, such as a weld. Further, the casing portions at the ends of the spring comprise an opening through the spring. Hereby, the casing forms a toroid or doughnut shape enclosing the spring.

Claims

1. A spring mattress, comprising: a plurality of interconnected coil springs enclosed in casings, wherein for at least one spring of the plurality of interconnected coil springs, casing portions arranged at opposite ends of the at least one spring are joined casing portions that are connected to each other through the at least one spring by a joint, wherein the joined casing portions comprise an opening through the at least one spring, wherein the joined casing portions at the opposite ends of the at least one spring are in direct contact with each other, the opening being a punched or cut out opening in the joined casing portions, the opening being arranged within a perimeter of the joint between the joined casing portions, wherein the joint is formed by a surface joint, wherein the joined casing portions are connected by a plurality of welding points that are distributed around the opening and are inside a volume space defined by the at least one spring so as to be located between the opening and the at least one spring.

2. The spring mattress of claim 1, wherein the opening is substantially circular.

3. The spring mattress of claim 1, wherein an average diameter of the opening is within a range of 2-50% of an average diameter of the at least one spring.

4. The spring mattress of claim 1, wherein the joint is formed by a mechanical connecting element.

5. The spring mattress of claim 1, wherein the casings form a plurality of strings interconnected side by side, each string of the plurality of strings comprising a continuous casing material, the casings being defined by at least one longitudinal connecting line extending parallel to a longitudinal direction of the string and a plurality of transverse connecting lines extending transversely to the longitudinal direction of the string, and the plurality of interconnected coil springs are arranged in the casings of the string.

6. The spring mattress of claim 5, wherein at least one longitudinal connecting line and the plurality of transverse connecting lines are arranged at sides of the plurality of interconnected coil springs, and thus between neighboring springs of the plurality of interconnected coil springs.

7. The spring mattress of claim 1, wherein the casings are made of a weldable textile material.

8. The spring mattress of claim 1, wherein a connection of the joined casing portions at the opposite ends of the at least one spring is such that the at least one spring is biased.

9. The spring mattress of claim 8, wherein the at least one spring is biased so that a length of the at least one spring in a biased state is smaller than ⅔ of the length of the at least one spring in a non-biased state.

10. The spring mattress of claim 1, wherein the at least one spring has a height which is less than a width of the at least one spring.

11. The spring mattress of claim 1, comprising a plurality of biased springs, wherein at least some biased springs of the plurality of biased springs are differently biased.

12. The spring mattress of claim 1, wherein an average diameter of the opening is within a range of 5-30% of an average diameter of the at least one spring.

13. The spring mattress of claim 1, wherein an average diameter of the opening is within a range of 10-25% of an average diameter of the at least one spring.

14. The spring mattress of claim 1, wherein the joint is formed by one of a glue or a weld.

15. The spring mattress of claim 1, wherein an average diameter of the opening is within a range of 0.5-5 cm.

16. A spring mattress, comprising: a plurality of interconnected coil springs enclosed in casings, wherein for at least one spring of the plurality of interconnected coil springs, casing portions arranged at opposite ends of the at least one spring are joined casing portions that are connected to each other through the at least one spring by a joint, wherein the casings form a plurality of strings interconnected side by side, each string comprising a continuous casing material, the casings being defined by at least one longitudinal connection line extending parallel to a longitudinal direction of the string and a plurality of transverse connecting lines extending transversely to the longitudinal direction of the string, wherein the joined casing portions comprise an opening through the at least one spring, wherein the joined casing portions at the opposite ends of the at least one spring are in direct contact with each other, the opening being a punched or cut out opening in the joined casing portions, the opening being arranged within a perimeter of the joint between the joined casing portions, wherein the joint is formed by a surface joint, wherein the joined casing portions are connected by a welding joint that is inside a volume space defined by the at least one spring so as to be located between the opening and the at least one spring.

17. A spring mattress, comprising: a plurality of interconnected coil springs enclosed in casings, wherein for at least one spring of the plurality of interconnected coil springs, casing portions arranged at opposite ends of the at least one spring are joined casing portions that are connected to each other through the at least one spring by a joint, wherein the casings comprise an upper sheet and a lower sheet, the upper sheet and the lower sheet being connected together along longitudinal and lateral connection lines, forming a checkerboard pattern, thereby forming individual pockets for the plurality of interconnected coil springs, wherein the joined casing portions comprise an opening through the at least one spring, wherein the joined casing portions at the opposite ends of the at least one spring are in direct contact with each other, the opening being a punched or cut out opening in the joined casing portions, the opening being arranged within a perimeter of the joint between the joined casing portions, wherein the joint is formed by a surface joint, wherein the joined casing portions are connected by a welding joint that is inside a volume space defined by the at least one spring so as to be located between the opening and the at least one spring.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will be described in more detail with reference to the appended drawings, showing embodiments of the invention.

(2) FIG. 1 is a perspective view of a part of a mattress according to an embodiment of the invention;

(3) FIG. 2 is a sectional side view of part of the mattress in FIG. 1 seen in the string direction;

(4) FIG. 3 is a perspective view obliquely from above of the mattress in FIGS. 1 and 2;

(5) FIG. 4 is a schematic perspective view obliquely from above of a device for manufacturing a mattress according to an embodiment of the invention;

(6) FIG. 5 is a view of part of the mattress as seen from above; and

(7) FIG. 6 is a schematic perspective view obliquely from above of the step of punching holes in the manufacture of a mattress according to an alternative embodiment of the invention.

(8) As illustrated in the figures, the sizes of layers and regions may be exaggerated for illustrative purposes and, thus, may be provided to illustrate the general structures of embodiments of the present invention. Like reference numerals refer to like elements throughout.

DETAILED DESCRIPTION OF THE INVENTION

(9) For the purpose of exemplification, the invention will now be described in more detail by way of an embodiment and with reference to the accompanying drawings.

(10) A spring mattress according to an embodiment of the invention comprises a plurality of interconnected coil springs 1 enclosed in casings 2, as shown in FIGS. 1 and 2. The casing is suitably made of a, preferably weldable, textile material, but also other materials, such as different types of plastic materials, can be used. It is also possible to use non-weldable textile materials, such as cotton cloth.

(11) The mattress comprises strings 3 of casing material 2, in which a plurality of pockets 4 are arranged. The pockets are here defined by at least one longitudinal connecting line 5 extending parallel to the longitudinal direction of the string and a plurality of transverse connecting lines 6 extending transversely to the longitudinal direction of the string. Preferably the strings comprise casing material of a folded piece of material, where the fold line extends in the longitudinal direction of the string. The closing longitudinal connecting line 5 is arranged at the opposite side of the string. Transverse connecting lines then extend between the fold line and the longitudinal connecting line. Alternatively, it is possible to use two or more pieces of material for making each string, in which case additional connecting lines may be required.

(12) In the mattress, the springs are here oriented in the pockets so that the connecting lines are arranged at the side of the springs and, thus, between neighboring springs. Preferably, the casing material portions at the ends of the springs are thus essentially free of other connections. However, it is also possible to arrange the longitudinal connection line on top of the strings, overlying the spring ends.

(13) According to an embodiment of the invention, for at least one of the springs, the casing portions arranged at the ends of the springs are moved towards each other, through the spring, and connected to each other by connecting means 7 to provide at least a certain degree of bias. Preferably the casing portions are moved so far towards each other as to make contact with each other, but of course it is possible to interconnect them also otherwise, by wire, a long clamp or the like. The connecting means may consist of a mechanical connecting element, such as a clamp, a rivet or the like, or by a surface joint, such as an adhesive, a weld or the like. Other fixing elements are, however, also conceivable. The load on the fixing element is normally small since the fixing elements are only loaded when the mattress is unloaded, whereas there is no load at all when the mattress is loaded. In a preferred embodiment, the joint is formed by one or several weld(s).

(14) Further, end portions comprise an opening 9 through the joint, and through the spring. The opening 9 may preferably be substantially circular, but other shapes may also be used. Openings 9 though the length of the spring can help provide proper ventilation of the mattress. The opening is here substantially circular, as seen in FIG. 5, however other shapes of the opening can also be used. The diameter of the opening may for instance be between 5 mm and 50 mm, preferably between 10 mm and 30 mm, more preferably between 15 mm and 25 mm.

(15) The end portions are here connected by welding points 10 distributed around the substantially circular opening 9, as seen in FIG. 5. Here four welding points are distributed around the opening, however any number of welding points, such as three, six or eight, can be used. Alternatively, a continuous weld around the opening can be used. The end portions are preferably connected to each other by welding, in which case a weld surface is arranged to connect the end portions to each other. The size and/or the location of the weld can advantageously be controllable and may be selected to give a desired height of the mattress and bias on the springs.

(16) Coil springs of many sizes can be used in connection with the present invention, and basically any size of spring can be used. However, it is preferred to use springs with a diameter of 2-10 cm, most preferred about 6 cm. The springs preferably comprise at least three turns, preferably fewer than 10 turns. Moreover they are advantageously made of spiral wire with a thickness in the range 0.5-3.0 mm, preferably a wire thickness in the range 1.25-2.50 mm. Preferably the springs are slightly spool-shaped, that is with smaller turns at the top and bottom.

(17) In a mattress as described above, as illustrated in FIGS. 1 and 3, the strings with springs are preferably arranged side by side and fixed to each other. Preferably the rows are connected to each other by fixing points 8, which advantageously connect the longitudinal connecting line 5 of one string to the side of the neighboring string. Of course, a smaller or greater number of fixing points than is shown is conceivable. It is also possible to arrange a longer fixing line instead of a plurality of shorter fixing points. The connection of strings to each other can occur by welding or gluing. Preferably, the welding or gluing surface is distributed around the opening to provide good strength to the interconnection. This may for instance be achieved by point surfaces distributed symmetrically around the opening or by a continuous line surface around the opening. Also this connection can, however, alternatively occur by means of clamps, by Velcro tape, or in some other-suitable manner.

(18) By arranging the interconnection of the strings via the longitudinal connecting line, automatic separation of the strings is provided, without requiring additional casing material. This is advantageous on the one hand since it results in a mattress with fewer springs, which has been found very favorable from the viewpoint of comfort and, on the other, since the mattress will thus be more cost-effective.

(19) The solution with strings of continuous casing material in which there are individual casings for the springs is merely one of many ways to carry out the invention. The invention may for instance involve individual casings for the springs which are then attached to each other or a continuous sheet of casing material for the whole mattress comprising casings for the individual springs, or any other solution when it comes to the casing material.

(20) The mattress according to the invention can be manufactured by enclosing springs in pockets in strings of a casing material, the pockets being made of a continuous casing material with at least one longitudinal connecting line extending parallel to the longitudinal direction of the string and a plurality of transverse connecting lines extending transversely to the longitudinal direction of the string. Moreover, the method comprises the steps of moving casing portions arranged for the ends of the spring towards each other, connecting them to each other and punching or by any other means creating an opening through the casing portions at the ends of the spring. There might further be a step of interconnecting strings side by side.

(21) For instance, the strings can be manufactured by the casing material being folded in two, and transverse welds being arranged to form open pockets. Subsequently compressed springs are inserted into the pockets, after which the pockets are sealed by a weld extending along the string. Moreover there is arranged, preferably without turning the springs, an additional weld through each spring for connecting the end portions to each other, an opening is punched through the casing portions at the ends, preferably in the middle of a number of welding points or a continuous weld, and a plurality of springs are joined side by side to form a mattress, the longitudinal welds being positioned between the strings.

(22) The steps can be performed in different orders, and so that the connecting lines are arranged at the side of the springs and, thus, between neighboring springs. The step of moving the end portions towards each other usually implies that bias occurs by connection by means of connecting elements in such a manner that the springs in the biased state have a smaller longitudinal extent than in the original, non-biased state. Such bias can occur either directly after encapsulating the springs in the casing material, that is before they are assembled to form a mattress, or once the mattress is assembled. Preferably, however, bias occurs before the springs are enclosed in the pockets of strings, in which case it is possible to use a considerably smaller amount of casing material. Especially the amount of casing material can be made smaller the greater the bias and the thinner the mattress. In this manner, conveniently all springs in the mattress layer are biased.

(23) In the manufacture of mattresses, it may also be ensured, as discussed above, that at least two neighboring strings are connected to each other so that an intermediate separation distance is provided between them.

(24) Moreover, the strings with springs are preferably interconnected side by side, as indicated in FIG. 3 for instance. As mentioned above, this can take place by arranging fixing points on the longitudinal connecting lines for fastening at the side of neighboring strings.

(25) A device for carrying out the method above comprises means for enclosing coil springs in pockets of strings, the pockets being made of a continuous casing material with at least one longitudinal connecting line extending parallel to the longitudinal direction of the string and a plurality of transverse connecting lines extending transversely to the longitudinal direction of the string. These means may comprise a device for folding casing material around a row of springs, and equipment for welding of connecting lines in the folded casing material, as schematically illustrated in FIG. 4. Instead of compressing the springs when placed in the casing, and while the casing is being folded over them, it is alternatively possible to compress the springs separately and then, in the compressed state, insert them into the folded casing.

(26) The welding equipment preferably comprises welding dies 11, 12 which are movable towards the casing material, and corresponding anvils 13, 14 on the opposite side. Preferably separate pieces of welding equipment are arranged to generate the longitudinal connecting lines and the transverse connecting lines respectively. The means for enclosing the coil springs is adapted to arrange the connecting lines at the side of the springs so that they are positioned between neighboring springs of the completed mattress.

(27) Further, the device comprises means for moving casing portions arranged for the ends of the spring towards each other and connecting them to each other and means for interconnecting strings side by side.

(28) The means for moving casing portions arranged for the ends of the spring towards each other and connecting them to each other preferably comprises an inserter 15 and, arranged at a distance therefrom, an anvil or counteracter 16. In use, springs are placed so that one end faces the inserter and the other the anvil. The inserter is movable towards and away from the anvil to move casing material at one spring end through the spring towards the casing material on the other side. The inserter 15 is preferably a welding die for generating a connecting weld. Alternatively, however, other fixing means can be provided instead. It is also possible to use a movable anvil, in which case both sides of the spring are pressed towards each other, after which stitching, welding or similar connecting may occur.

(29) The device also comprises means for punching holes in the casing portions at the ends of the springs. The punch here comprises a punching piece 17 and an abutment or anvil 18, the punch 17 here being punched through the spring towards the abutment 18 and thereby punching out a substantially circular opening in the casing portions at the ends of the spring. Alternatively, the openings can be created by for instance cutting. The casing may also be pre-holed to create the openings before the other steps.

(30) The interconnection of the casing portions may also be created in the same step as the creation of the opening, for instance by creating welding points around the punching simultaneously as doing the punching, as seen in FIG. 6. A circular insertion means 15 is here attached to a circular connecter 16 while a punch 17 travels through the tube shaped inserter and punches a hole in the casing portions through the spring. The connecter here comprises four protrusions 19 in the profile of the part to be connected to the insertion means, the protrusions defining the welding points to be created between the casing portions.

(31) A system according to the invention can advantageously comprise a plurality of parallel devices, such as two devices operating in parallel.

(32) Moreover, means are included for interconnecting the strings with springs preferably side by side, as indicated in FIG. 3 for instance. As mentioned above, this can take place by arranging fixing points on the longitudinal connecting lines for fastening to the side of neighboring strings.

(33) It is preferred for the bias of the springs to be performed so that the length of the springs in the biased state is less than ⅔ of the length of the same springs in the non-biased original state, and preferably less than ½. It is also preferred for the ratio between the length of the springs and the diameter thereof in the biased state to be less than 2, and preferably less than 1, and most preferred less than ½.

(34) The mattress stated above ensures guiding of the spring, which thus is prevented from turning or the like. In contrast to prior-art mattresses, the new mattress comprises, however, pocket strings where the springs are inserted through openings in the lateral direction which are then welded together, but where the springs have then not been turned. As a result, the weld will be arranged along the sides of the springs instead of over the ends. Moreover the smooth end portions are moved towards each other and attached by welding for instance. Therefore very thin mattresses can be provided in this manner, in fact down to a thickness of one or a few centimeters. For example, a mattress with a thickness of 25 mm can be provided. Thus the invention might be well suited for seat cushions, overlay mattresses to be placed on top of other mattresses and similar applications where thin mattresses are required. Thus being able to make overlay mattresses of pocket springs is very advantageous, not only because they can be made softer, thereby increasing the comfort, but also because springs are normally not fatigued over time, as is polyethylene or like materials. Mattresses according to the invention can be made very light, soft and comfortable, and also, due to the bias, very rigid and hard, as desired. The opening through the spring also ensures good ventilation of the mattress, thus providing better drying, cooling and/or heating, less growth of bacteria and the like, and increased comfort.

(35) The invention makes it possible to easily adjust the height of the spring elements by varying the position and size of the fixing means when connecting the end portions to each other. In this way it is also easy to provide different thicknesses of different portions of the mattress, or provide mattresses of different thicknesses, without having to make any changes in the manufacturing process in addition to this connection. The manufacture will in this way be very flexible and controllable. In particular it is possible to provide mattresses with a cup shape or the like to be used as seat cushions or other mattresses intended for sitting. Similar changes of height can also be used in other mattresses to control the user's position on the mattress.

(36) The invention has been described above by way of embodiments. Several variants of the invention are, however, conceivable. For instance, as mentioned above, other types of fixing elements can be used, as well as other solutions for the casing material, spring sizes etc. Furthermore, the device and the method can be designed in other ways. Such obvious variants must be considered to be comprised by the invention as defined by the appended claims.