String of pocketed springs, suspension for bedding mattresses comprising a plurality of such strings and mattress comprising such a suspension

Abstract

The invention relates mainly to a string of helical springs (2) housed in individual pockets formed between two panels folded one above the other of a strip of flexible fabric and delimited by connection zones securing the two panels to each other and comprising transverse connection zones which extend parallel to the longitudinal axes of the helical springs (2) and a longitudinal connection zone opposite and substantially parallel to the longitudinal fold zone of the two panels, according to which each pocket contains a helical spring (2) comprising two spring parts, respectively comfort (12) and support (13) connected in series to each other by an intermediate part (14) which is eccentric, the ratio between the length of the support part (13) and the length of the comfort part (12) being between 1.5 and 2.5.

Description

Technical field

[0001] The invention relates to a string of coil springs housed in individual retaining pockets and which is intended for the manufacture of pocket spring suspensions for bedding mattresses. Prior art and disadvantages of prior art

[0002] A known pocket spring suspension for bedding mattresses consists of a plurality of parallel strings of springs housed respectively in individual pockets. A string of pocket springs is secured to each adjacent string by lines of adhesive spread over the mutually contacting outer arcuate tangential surfaces of the pockets. The lines of adhesive for securing a pocket of the string to an adjacent pocket of the adjacent string may consist of two parallel strips of adhesive located at a certain distance from each other and spread over the outer arcuate face of the pocket perpendicular to the longitudinal direction of the spring housed in that pocket.

[0003] The individual pockets of a string, in each of which a spring is housed, are formed between two sides folded one above the other of an elongated, heat-sealable strip of flexible fabric and are delimited by heat-seal lines transverse to the strip, located between the adjacent springs and parallel to the longitudinal direction of each spring, and a longitudinal heat-seal line opposite and substantially parallel to the longitudinal fold zone of the two sides of the strip.

[0004] Thus, the successive transverse heat-sealing lines extend rectilinearly over practically the entire width of the strip of the rosary and are located at a determined distance from each other so as to define the width of each pocket for housing a spring and the longitudinal heat-sealing line defines the height of each pocket.

[0005] However, this known suspension has the disadvantage of only offering one type of comfort, typically firm, soft or intermediate.

[0006] To overcome this drawback, there is publication FR 2 861 270 in the name of the applicant which describes a pocket spring suspension for bedding mattresses comprising a plurality of strings of pocket helical springs assembled together as described above. According to this known suspension, each pocket of a string contains two barrel-shaped helical springs connected in series to each other by at least one central coil of smaller diameter. This configuration of springs ensures both firm support of the mattress composed of such strings of springs, while offering a feeling of comfort to the user.

[0007] However, the balance between sleeping firmness and comfort felt by the user lying on a mattress formed from a set of strings such as described in the applicant's publication is not optimized. Objective of the invention

[0008] The present invention aims to overcome the above disadvantages of known suspensions. Statement of the invention

[0009] To this end, the invention relates to a string of helical springs housed parallel to each other in individual retaining pockets formed between two panels folded one above the other of a flexible, elongated fabric strip, and delimited by connection zones securing the two panels to each other and comprising transverse connection zones which extend parallel to the longitudinal axes of the helical springs and a longitudinal connection zone opposite and substantially parallel to the longitudinal fold zone of the two panels, according to which each pocket contains a helical spring comprising two spring parts, respectively comfort and support, which spring parts are connected in series to each other by at least one turn of smaller diameter forming an intermediate part which is eccentric between said two spring parts, and, for each spring of the string,the ratio between the length of the holding part and the length of the comfort part is between 1.5 and 2.5,

[0010] The rosary of the invention may also include the following optional characteristics considered in isolation or according to all possible technical combinations: For each spring in the chain, the ratio of the length of the holding portion to the length of the comfort portion is 2. For each spring in the chain, the ratio of the coil pitch of the holding portion to the coil pitch of the comfort portion is between 1 and 2. For each spring in the chain, the ratio of the coil pitch of the holding portion to the coil pitch of the comfort portion is 1.5. For each spring, the ratio of the total length of the uncompressed spring to the total length of said compressed spring is between 1.1 and 1.2. For each spring, the total length of the compressed spring is between 20 and 23 centimeters. For each spring, the ratio of the length of the comfort portion to the length of the intermediate portion is between 1.5 and 2.5.Each transverse connecting zone comprises, between two adjacent pockets, a first width at the comfort portion of each spring, a second width at the support portion of each spring, and a third width at the intermediate portion of each spring, which third width is greater than each of the first and second widths. Each transverse connecting zone comprises, between two adjacent pockets and at each intermediate portion of smaller diameter, a space delimited by two connecting lines spaced from each other to define a closed and elongated contour parallel to the longitudinal axes of the springs. The space delimited by the two connecting lines is more elastic than the rest of the flexible fabric strip.The space delimited by the two connecting lines is an elongated window-shaped recess which is formed by removing fabric material between the two connecting lines.

[0011] The invention also relates to a pocket spring suspension for bedding mattresses, comprising several parallel strings of pocket springs connected to each other, each string being as described above.

[0012] The invention also relates to a bedding mattress intended to be placed on a bed base and comprising an internal pocket spring suspension as described previously. Presentation of figures

[0013] Other characteristics and advantages of the invention will emerge clearly from the description given below, for information purposes only and in no way limiting, with reference to the appended figures, among which: [ Fig. 1 ] There figure 1 represents a perspective view of a rosary spring according to the invention; [ Fig. 2 ] There figure 2 represents an elevation view of a string of springs according to the figure 1 bagged. Detailed description of the invention

[0014] It is first specified that in the figures, the same references designate the same elements regardless of the figure in which they appear and regardless of the form of representation of these elements. Similarly, if elements are not specifically referenced in one of the figures, their references can be easily found by referring to another figure.

[0015] It is also specified that the figures essentially represent an embodiment of the subject of the invention but that there may be other embodiments which meet the definition of the invention.

[0016] Referring first to the figure 2 , the string 3 with pocket springs 2 is manufactured by the known method consisting first of all in inserting the axially compressed springs 2 between two superimposed sections of a strip of elongated heat-sealable fabric 8 in positions or locations spaced longitudinally on the strip and then in thermally welding the two sections to each other along heat-seal zones 9 transverse to the strip 8 arranged between the successive compressed springs 2, each heat-seal zone 9 between two springs 2 being formed of several lines, and a heat-seal zone 10 formed of a line extending substantially parallel to the longitudinal fold zone 11 of the sections, so as to form a retaining pocket 6 for each spring.After forming these pockets, the springs 2 are rotated inside the pockets so that they relax so that their longitudinal axes are transverse to the longitudinal fold zone 11 and, consequently, parallel to the transverse heat-sealing lines 9. The non-woven material of the strip 8 is flexible and the heat-sealing lines 9, 10 are obtained by ultrasound.

[0017] In particular and for each spring 2, the ratio between the total length of said uncompressed spring 2 and the total length of said compressed spring 2 is between 1.1 and 1.2. This ensures an optimal compromise between stability of the string of springs 3 and latitude of deformation of the springs 2 in said string 3. Furthermore, in order to maintain this optimal compromise, the total length of the compressed spring is between 20 and 23 centimeters.

[0018] Each string 3 thus makes it possible to effectively hold a spring 2 in each pocket 6 without the risk of it being positioned askew when a load is applied to it vertically and also makes it possible to increase the sleeping independence of a mattress equipped with such strings.

[0019] Adjacent strings 3 of pocket springs 2 are connected to each other by discontinuous or continuous adhesive lines (not shown) along the longitudinal direction of the springs 2 to form a pocket spring suspension of a bedding mattress.

[0020] According to the embodiment of the invention shown in figures 1 And 2, each pocket 6 of a string 3 contains a helical compression spring 2 comprising two spring parts 12, 13 connected in series to each other by one or more central turns 5 of smaller diameter forming an intermediate part 14, which spring parts 12, 13 are constituted respectively by an upper barrel-shaped spring part called comfort 12 and a lower spring part also barrel-shaped called maintenance 13 arranged on either side of the intermediate part 14.

[0021] The comfort spring parts 12 are said to be upper because they must be located in the upper portion of a mattress with the smaller diameter end turns 22 of these comfort parts 12 arranged under the sleeping area of ​​the mattress. The support spring parts 13 are said to be lower because they must be located in the lower portion of the mattress with their end turns 23 constituting the bases of these support parts 13 resting on the fold area 11 and intended to rest on the upper face of a bed base S.

[0022] The 3 strings of springs 2 in pockets having the configuration shown in figure 2 are intended for the manufacture of mattresses of relatively great thickness and which are not intended to be turned by their user, that is to say they only have one sleeping face, the one under which the comfort part 12 of the springs 2 are located.

[0023] According to the invention and with particular reference to the figure 1 , for each spring 2 of the string 3, the ratio between the length of the holding part 13 and the length of the comfort part 12 is between 1.5 and 2.5, and is preferably 2. In this way, a mattress consisting of a suspension formed from a plurality of strings 3 with the springs 2 of the invention combines firm holding properties thanks to the holding parts 13 of the springs 2, with flexibility properties on the upper part of the mattress conferred by the comfort parts 12 of the springs 2, giving a feeling of comfort to the user using the mattress.

[0024] Furthermore, the comfort part 12 typically comprises a turn arranged between its end turns 22 and the intermediate part 14, while the holding part 13 comprises two turns arranged between its end turns 23 and the intermediate part 14.

[0025] Furthermore, the ratio between the coil pitch 20 of the holding part 13 and the coil pitch 21 of the comfort part 12 is between 1 and 2, and is preferably of the order of 1.5. This configuration optimizes the optimal balance between comfort felt - thanks to the comfort parts 12 of the springs 2 - and sleeping firmness - thanks to the holding parts 13 of the springs 2 - the stiffness of the comfort part 12 being less than that of the holding part 13.

[0026] Finally, for each spring 2, the ratio between the length of the comfort part 12 and the length of the intermediate part 14 is between 1.5 and 2.5. This configuration avoids a collapse effect of the comfort part 12 of the spring 2 when it compresses under the weight of the user, if it were only made up of coils of small diameter, equal to the diameter of the coils of the intermediate part 14.

[0027] There figure 2 shows that each transverse heat-sealing line 9 is divided towards the longitudinal line 10 into two oblique heat-sealing lines 15 defining an open V-shape in the opposite direction to the fold zone 11 or towards the line 10 so as to reduce the width of each retaining pocket 6 of the comfort part 12 of the spring considered 2 in the area of ​​this pocket 6 where the upper end part of the smaller diameter of the turns 22 of the comfort part 12 of the spring is housed.

[0028] The two oblique heat-sealing lines 15 located on either side of a comfort part 12 have an inclination and a height from their rectilinear transverse heat-sealing line 9 such that they configure a part of the upper pockets in an approximately truncated cone shape making it possible to enclose practically without play the approximately truncated cone-shaped upper end part of the smaller diameter of the comfort part 12 of the spring.

[0029] There figure 2 further shows that the string of pocket springs 3 is provided with cutouts 16 made by removing material from the strip 8 between the branches of the different pairs of oblique lines 15 to configure each cutout 16 substantially in the shape of a V embedded in the conjugate V shape defined by two oblique heat-sealing lines 15 associated with a transverse heat-sealing line 9.

[0030] Two successive cutouts 16 of the strip 8 define between them an approximately truncated pocket portion allowing axial compression or depression of at least the corresponding comfort part 12 without causing depression of the neighboring comfort parts 12 due to the absence of fabric between two adjacent truncated pocket portions. Thus, the cutouts 16 provide the springs 2 of the chain 3 with more independence than those of a traditional chain.

[0031] Furthermore, each lower transverse heat-sealing line 9 is divided opposite the longitudinal connection line 10, as opposed to the upper transverse heat-sealing line 9 with two upper oblique connection lines 15, into two other oblique connection lines 15 defining a V-shape open towards the fold zone 11 of the two sides of the strip 8 and a lower V-shaped cutout 16 is produced by removing material from the part of fabric located between the two branches of the V-shape of the two lower oblique lines 15 to give each end portion of a pocket 6 a substantially frustoconical shape for housing an end part of the turns of smaller diameter of the holding part 13 of the spring in question 2.

[0032] There figure 2 shows that each transverse connection zone 9 comprises, between two adjacent pockets 6, a first width L1 at the comfort part 12 of each spring 2, a second width L2 at the holding part 13 of each spring 2, and a third width L3 at the intermediate part 14 of each spring 2, which third width L3 is greater than each of the first and second widths L1, L2.

[0033] Each transverse connection zone 9 comprises, between two adjacent pockets 6 and at the level of each intermediate part of smaller diameter 14, a space delimited by two connection lines 17 spaced from each other to define a closed and elongated contour parallel to the longitudinal axes of the springs 2. Preferably, this contour is oval in shape.

[0034] The two connecting lines 17 thus delimit an elongated oval space, which is made of a more elastic material than the rest of the strip of fabric 8. According to a preferred variant, the space delimited by the two connecting lines is a recess 18 formed by removing fabric material between the two substantially arcuate connecting lines 17 so that this recess has approximately an elongated oval shape parallel to the transverse line 9.

[0035] The presence of the arcuate connecting lines 17 and the recesses 18 at the intermediate part 14 of the springs 2 between the adjacent pockets 6 makes it possible on the one hand to effectively maintain the comfort 12 and support 13 parts of the springs 2 in their respective pockets so that they can work vertically in compression when a load is applied to them and to prevent the comfort 12 and support 13 parts from becoming skewed to catch on the other neighboring comfort 12 and support 13 parts causing either a sagging of the string 3 or noise, and on the other hand to increase the criterion of sleeping independence of a mattress provided with strings 3 conforming to that of the figure 2 , compared to a mattress with traditional barrel-shaped pocket springs.

[0036] The recesses 18 between the adjacent pockets 6 of a string 3 can be made by any known means, for example by ultrasound, by a cutting and perforating machine, or by punching.

[0037] Finally and alternatively, the recesses 18 can simply be replaced by crushing, by flattening or compression, the intermediate part 14 of the spring 2.

[0038] The invention has been described with reference to strings whose pockets are formed from transverse and longitudinal heat-sealing lines, but it is understood that it can be applied to strings whose transverse and longitudinal lines are produced by sewing.

Claims

1. String (3) of helical springs (2) housed parallel to each other in individual retaining pockets (6) formed between two panels folded one above the other of a flexible, elongated fabric strip (8), and delimited by connection zones (9, 10) securing the two panels to each other and comprising transverse connection zones (9) which extend parallel to the longitudinal axes of the helical springs (2) and a longitudinal connection zone (10) opposite and substantially parallel to the longitudinal fold zone (11) of the two panels, according to which each pocket (6) contains a helical spring (2) comprising two spring parts respectively comfort (12) and support (13), which spring parts (12, 13) are connected in series to each other by at least one turn (5) of smaller diameter forming a intermediate part (14) which is eccentric between said two spring parts (12, 13), characterized in that,for each spring (2) of the chain (3), the ratio between the length of the holding part (13) and the length of the comfort part (12) is between 1.5 and 2.5, in that , for each spring (2) of the chain, the ratio between the coil pitch (20) of the holding part (13) and the coil pitch (21) of the comfort part (12) is 1.5, and in that for each spring (2), the ratio between the total length of the uncompressed spring and the total length of said compressed spring is between 1.1 and 1.

2.

2. Rosary (3) according to the preceding claim, characterized in that , for each spring (2) of the chain, the ratio between the length of the holding part (13) and the length of the comfort part (12) is 2.

3. Rosary (3) according to the preceding claim, characterized in that , for each spring (2), the total length of the compressed spring (2) is between 20 and 23 centimeters.

4. Rosary (3) according to any one of the preceding claims, characterized in that , for each spring (2), the ratio between the length of the comfort part (12) and the length of the intermediate part (14) is between 1.5 and 2.

5.

5. Rosary (3) according to any one of the preceding claims, characterized in that each transverse connection zone (9) comprises, between two adjacent pockets (6), a first width (L1) at the comfort part (12) of each spring (2), a second width (L2) at the holding part (13) of each spring (2), and a third width (L3) at the intermediate part (14) of each spring (2), which third width (L3) is greater than each of the first and second widths (L1, L2).

6. Rosary (3) according to any one of the preceding claims, characterized in thateach transverse connection zone (9) comprises, between two adjacent pockets (6) and at the level of each intermediate part of smaller diameter (14), a space delimited by two connection lines (17) spaced from each other to define a closed and elongated contour parallel to the longitudinal axes of the springs (2).

7. Rosary (3) according to the preceding claim, characterized in that the space delimited by the two connecting lines (17) is more elastic than the rest of the flexible fabric strip (8).

8. Rosary (3) according to the preceding claim, characterized in that the space delimited by the two connecting lines (17) is a recess (18) in the form of an elongated window which is formed by removing fabric material between the two connecting lines (17).

9. Pocket spring suspension for bedding mattresses, comprising several parallel strings (3) of pocket springs (2) connected to each other, characterized in that each string (3) is in accordance with any one of the preceding claims.

10. Bedding mattress intended to be placed on a box spring and comprising an internal pocket spring suspension (2) in accordance with the preceding claim.

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