Patent Publication Number: US-11653770-B2

Title: Pocket spring core and method for producing the same

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is the National Stage of PCT/EP2018/070087 filed on Jul. 25, 2018, which claims priority under 35 U.S.C. §119 of German Application No. 10 2017 117 833.3 filed on Aug. 7, 2017, the disclosures of which are incorporated by reference. The international application under PCT article 21(2) was not published in English. 
     BACKGROUND OF THE INVENTION 
     The invention relates to a pocket spring core according to the preamble of claim  1  as well as a method for producing a pocket spring core. 
     Such spring cores are used in many areas of application. They are primarily used in the manufacture of mattresses or furniture upholstery. 
     In particular, in order to achieve sufficient edge stability, which is desired when the cushion or mattress is used as a seating area, it is known to provide the spring core with an upper and lower circumferential edge reinforcement consisting of a round or flat material, preferably metal. 
     Such a spring core is known for example from WO 96/35 355 A1. However, this spring core cannot be rolled up and unrolled, so that it does not meet the requirements for optimized production. 
     In order to finish the mattress or upholstered part as an end product, the spring cores usually have to be transported from the place of manufacture to the mattress production, wherein the respective production sites can be very far apart. 
     Since the spring cores take up a relatively large volume with low weight due to their nature in the position of use, the transport costs of these spring cores are disproportionately high. 
     In order to achieve a different zoning in their suspension behavior, also for the above-mentioned edge reinforcement, without a circumferential metal frame, banks of springs are used whose springs are harder than those of neighboring banks of springs. This is achieved by various selection criteria, e.g. by deviating wire diameters or by changes in the number of turns. Even a selection of different material properties can cause a correspondingly changed spring behavior, as can waist formation of the individual springs. 
     In the mechanical production of banks of springs, banks of springs can only ever be equipped with the same springs. In order to assemble banks of springs with partially different springs to a spring core, wherein, according to the generic design, adjacent banks of springs are connected to each other, a previously described frame is used which encloses the spring core completely. The banks of springs, of which at least one part consists in a manner of speaking of individual banks of springs which differ in their spring behavior, extend in the longitudinal direction of a rectangular elongated spring core. This means that the partial banks of springs of a bank of springs add up to the total length of the spring core. 
     Apart from the fact that the described problems arise when fixing the partial banks of springs by means of a metal frame, a complete mechanical production of the spring core is not possible and therefore no automation, since the circumferential metal frame must be fixed manually after joining and connecting the adjacent banks of springs. 
     All in all, the generic prior art is extremely unsatisfactory, especially with regard to cost optimization, which is always the goal. 
     The invention is based on the object of developing a pocket spring core of the generic type as well as a method for manufacturing such a pocket spring core in such a way that mechanical automatic production of the spring core is possible overall and cost optimization is achieved. 
     SUMMARY OF THE INVENTION 
     This object is solved by a spring core with the features of claim  1  and a method for producing the spring core. 
     The invention now creates the possibility of creating any number of different zonings of the spring core by either mechanically producing banks of springs with the same springs or partial banks of springs, depending on the claim, each with different spring characteristics of the individual springs, which are then joined together in further method steps in such a way that banks of springs with regionally different spring behavior result. The individual springs of a partial bank of springs are identical in their spring characteristics. 
     In a manner known per se, this spring characteristic can be influenced, for example, by the material selection of the spring wire, the wire diameter and the spring shape; the latter, for example, as a waisted, cylindrical or barrel-shaped design. 
     The new pocket spring core offers clear advantages over a prior art spring core in terms of manufacturing costs, handling and freedom of design. 
     As mentioned, the production of the new pocket spring core can take place fully automatically, i.e. mechanically, with regard to both the production of the partial banks of springs, their assembly to form a thus complete pocket spring core, and the interconnection of adjacent springs with different pocket springs in terms of their spring characteristics. 
     In addition, individual production of pocket spring cores is possible, depending on the needs of the future user. This includes the consideration of the suspension behavior of different zones. This means, for example, that one-sided, multi-sided or circumferential edge reinforcement is possible without any problems with correspondingly harder spring characteristics. Likewise, preferred zones within the lying surface can be individually adapted during the production of the pocket spring core and, due to the automated production process, are essentially cost-neutral. 
     The absence of a circumferential metal frame also makes further processing of the pocket spring core into a mattress or padding that can be used in other ways unproblematic, especially with regard to transport from the pocket spring core production plant to the processing plant. This is mainly due to the fact that the pocket spring core can be rolled up and thus only requires a small amount of transport space, which also contributes to cost optimization. 
     In principle, the invention according to which partial banks of springs of adjacent banks of springs are of different lengths and these adjacent partial banks of springs are connected to each other creates a meshing from which a firm connection of all banks of springs results, although the partial banks of springs with different spring behavior of a bank of springs cannot be connected to each other, at least not mechanically, as is possible with the connection of several adjoining banks of springs. 
     In a manner known per se, the parallel juxtaposition of the partial banks of springs can be achieved by gluing or welding, which also takes place just as mechanically as the production of the partial banks of springs. 
     The method for the mechanical production of a pocket spring core is, in accordance with the invention, designed in such a way that first at least a part of the banks of springs are produced as partial banks of springs with different spring behavior in different lengths, then adjoining partial banks of springs are connected to one another, wherein partial banks of springs with different spring characteristics overlap with their free end, so to speak, and are likewise connected to one another in this overlap region. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    shows a schematic illustration of a section of a pocket spring core according to the invention in perspective view, 
         FIG.  2    shows a schematic illustration of a section of another example of a pocket spring core according to invention in a plan view. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The figures each show a section in the region of a corner of a pocket spring core, having a plurality of pocketed springs  4 ,  5 , of which several form a bank of springs  1  arranged one behind the other in a row, wherein the springs  4 ,  5  each lie in a flexible pocket, preferably formed from textile material. These pockets are connected to each other by webs  6 . 
     Several of the banks of springs  1 , which are arranged side by side and connected to each other, for example by gluing or welding, form a lying surface, wherein the length of the banks of springs  1  correspond to the length of the rectangular lying surface. 
     In the example shown, the individual banks of springs  1 , disposed in parallel next to each other, are each formed by partial banks of springs  2 ,  3 , whose spring behavior is different, which is illustrated in the figures by the different line widths of the pocketed springs  4 ,  5 . 
     According to the invention, the partial banks of springs  2 ,  3  are of different lengths, in the examples by one spring  4 ,  5  each. 
     Since the length of the individual banks of springs  1  is the same, the connecting region of the partial banks of springs  2 ,  3  leads to meshing, i.e. according to the example in  FIG.  2   , a shorter partial bank of springs  3  is arranged between two longer partial banks of springs  3 , so that the partial bank of springs  3  completing the bank of springs  1  projects between the two longer partial banks of springs  3  and, like the short partial bank of springs  3 , is fastened to the longer partial banks of springs  3  on both sides in the region of a connection point  7 . In addition, all adjoining banks of springs  1  are connected to each other in the waist area of their individual springs  4 ,  5  or at their pockets. 
     In the variant of the invention shown in  FIG.  2   , the lower bank of springs  1  forming an outer edge of the lying surface in the drawing plane is continuously equipped with the same springs  5  and thus forms an edge reinforcement, as also the angled row of adjoining springs  5  resulting from the last spring  5  of the adjoining banks of springs  1 , wherein this edge reinforcement can be circumferential. 
     The springs  5  shown in the figures with larger line widths are harder in their spring characteristics than the springs  4  shown with smaller line widths. 
     The arrangement of the partial banks of springs  2 ,  3 , depending on the desired spring behavior of the corresponding areas of the spring core, can be selected at will and only depends on the customer&#39;s requirements.