Patent Publication Number: US-10766220-B2

Title: Method and device for producing a cushioning product and cushioning product

Description:
This application is a divisional of U.S. patent application Ser. No. 14/100,972 filed Dec. 9, 2013, which is hereby incorporated by reference herein as if fully set forth in its entirety. 
    
    
     The invention relates to a method and to a device for producing a cushioning product. The invention further relates to a cushioning product as such. The cushioning product is here produced from a flat, longitudinal two- or multilayered paper strip. 
     From EP 1 539 474 B1, a cushioning product is known which is crumpled from a two-layered paper tube. Also known from the known document are a method and a device by means of which the cushioning product disclosed therein is crumpled from the longitudinal paper tube. 
     The present invention furthermore aims to provide a method for producing a cushioning product that is particularly suitable for cushioning objects contained in packages. 
     The aim is achieved by a method having the features of claim  1 . 
     The method according to the invention comprises the following steps: 
     providing a flat, longitudinal, two- or multilayered paper strip, wherein the individual layers of the paper strip are connected to one another in at least some sections in a middle area extending in the longitudinal direction, and wherein the individual layers of the paper strip comprise marginal areas that are not connected to one another, 
     opening the paper strip at adjacent marginal areas to form a paper strip having a star-shaped cross section, and 
     crumpling the paper strip along the central area. 
     According to the method of the invention, a flat, longitudinal, two- or multilayered paper strip is thus produced. The individual layers of the paper strip are here connected to one another in at least some sections in the middle area extending in the longitudinal direction. It is conceivable for the connection to be made by positive connection or bonded connection. In particular, it has been found to be particularly advantageous to glue the individual layers in the middle area. Here, the glue connection can extend preferably along a line extending in the longitudinal direction. The glue connection can here be made in just some sections, for example, at some points. However, the glue connection can also be produced along a closed line. 
     The individual layers of the paper strip moreover do not have mutually connected marginal areas. In the initial state of the paper strip, which can be flat, in particular pressed flat, adjacent marginal areas preferably abut against each other. In a two-layered paper strip whose middle section is connected, four marginal areas are then preferably present, wherein in each case two marginal areas in the flat state then abut against each other. However, it is also possible to provide three or more layers. Then, three or more marginal areas in the flat state are provided which abut against each other. The paper strip, which comprises in particular two layers, is relatively easy to produce. Here, it is conceivable that it is only at the time when the paper strip is provided that the individual layers are connected to one another in the middle area, or that the individual layers are connected to one another in the middle area already before the paper strip is provided, that is in a previous work step, which can also take place at another site. 
     According to the next process step of the invention, the adjacent, particularly mutually abutting, marginal areas are opened to form a paper strip with a star-shaped cross section. In the case of a two-layered paper strip, a star-shaped paper strip having a total of four protruding “rays” is then produced, wherein said rays are connected in the middle, central area, as before. If three layers are provided, then, in particular, a “star” with six “rays” is formed; if more layers are provided, a “star” having correspondingly more “rays” is formed. 
     The respective adjacent rays here preferably enclose an angle in the range from 60° to 120° and preferably in the range from 70° to 100°, and furthermore preferably in the range from 85° to 95°. 
     In the next process step, the paper strip is then crumpled at least along the middle area. The crumpling here occurs in the longitudinal direction at least along the middle area in such a manner that sections of the middle area are moved or shifted toward each other, so that the length of the paper strip in the crumpled state, that is the length of the cushioning product, is shorter than the paper strip in the uncrumpled state. As a result, there is also a greater restoring resilience in the longitudinal direction of the crumpled paper strip in comparison to the uncrumpled paper strip. 
     The opening of the adjacent marginal area of the paper strip can here occur preferably via one or more opening cores, over which the paper strip is moved. The movement of the paper strip over the opening cores can here occur preferably by means of a machine using a drive. In particular, it is conceivable that, in the middle area of the paper strip, driving rollers seize the paper strip, thereby moving the paper strip. 
     The crumpling can occur according to the invention with a first set of driving rollers and with a second set of driving rollers in such a manner that the second set of driving rollers rotates at an angular speed which is lower than the angular speed of the first set of driving rollers. By means of such driving rollers, the paper strip can be moved not only over opening cores, but a crumpling along the longitudinal direction in the middle area can also be provided as a result. Depending on how large the difference between the angular speeds of the two sets of driving rollers is, a varying degree of crumpling of the paper strip is possible. 
     For the respective setting of a specified length of the cushioning product it is advantageous if a separation of the cushioning product into two areas occurs by slowing or stopping the first set of driving rollers, while the second set of driving rollers continues to be driven. Advantageously, the two areas are separated from each other by tearing apart. In this context, it is advantageous if the paper strip comprises predetermined separation places that extend transversely to the longitudinal direction, in particular in the form of perforations. 
     The mentioned aim is also achieved by a device for producing a cushioning product, in particular for carrying out the method according to the invention, according to the features of claim  5 . Such a device comprises an inlet area for a flat, longitudinal two- or multilayered paper strip. The paper strip as such is here formed in such a manner that the individual layers of the paper strip are connected to one another in at least some sections in a middle area extending in the longitudinal direction, and the individual layers of the paper strip do not comprise mutually connected marginal areas. The device furthermore provides an opening core for opening the paper strip along adjacent marginal areas to form a paper strip with a star-shaped cross section. Moreover, the device provides an advance mechanism for moving the marginal areas over the at least one opening core and a crumpling mechanism for crumpling the paper strip along the middle area. The inlet area, the opening core, the advance mechanism, and the crumpling mechanism are here designed preferably in such a manner that the above-described method according to the invention can be carried out with the device. 
     Advantageously, the device provides at least two mutually facing opening cores, which are spaced apart from each other in the transverse direction so that the middle area of the paper strip can be moved through, between the opening cores. As a result, the marginal areas of the layers can be opened, so that a star-shaped paper strip is formed. The middle area of the paper strip, in which the individual layers are connected to each other, can nevertheless be moved through, between the opening cores. 
     Advantageously, the opening cores are designed in such a manner that, in cross section, that is transversely to the longitudinal direction, they comprise wedge sections directed toward each other. As a result, the formation of a paper strip with a star-shaped cross section can be ensured. 
     Furthermore, it is advantageous for the opening cores to have, in a longitudinal section, that is in the longitudinal direction, wedge-shaped opening sections directed toward the inlet area. By means of these opening sections, an opening of the flat paper strip along adjacent marginal areas can occur in such a manner that the adjacent marginal areas are opened apart from each other, so that in the end a paper strip is formed which has a star-shaped cross section. Opening sections are consequently used to convert the paper strip of flat design into a paper strip which has a star-like shape in cross section. 
     Here, separating elements, which engage between adjacent marginal sections, can be arranged before the opening cores in the longitudinal direction. The separating elements are consequently used to engage in the adjacent marginal sections, which lie in particular one on top of the other, to ensure then a consistent opening of the marginal areas. The separating elements in particular have a thin and planar design and, moreover, they are spaced from each other in the transverse direction, like the opening cores, so that the middle area of the paper strip, in which the individual layers are connected to one another, can be passed through, between the separating elements. The separating elements can be designed, in particular, as separation disks or metal plates and, moreover, they can be designed to form a single part with the opening cores, particularly at the wedge tips of the opening sections. 
     Furthermore, it is advantageous if, in the inlet area, a guide roller extending transversely to the longitudinal direction is arranged, over which the flat paper strip is guided. This is advantageous if the paper strip, for example, is rolled off a supply roll or taken from a supply stack. 
     The advance mechanism for moving the marginal areas over the preferably two opening cores can be formed by a first set of driving rollers. This first set of driving rollers can comprise two rollers arranged one above the other, which seize the paper strip respectively above and below the middle area of the paper strip before the opening wedge in the longitudinal direction. The two rollers can here be arranged in particular in such a manner that they seize the paper strip in the area between the separating elements. 
     Moreover it is advantageous for the crumpling mechanism to be formed by a second set of driving rollers that work together with the first set of driving rollers, in such a manner that the second set of driving rollers can be rotated at an angular speed that is lower than the angular speed at which the first set of driving rollers can be rotated. As a result, the paper strip can be moved over the first set of driving rollers; a crumpling of the paper strip can be achieved with the second set of driving rollers. 
     The second set of driving rollers here can comprise two rollers arranged one above the other, which seize the paper strip above and below the middle area of the paper strip in the area between or after the opening wedges in the longitudinal direction. Consequently, it is advantageous if the first set of driving rollers seizes the paper strip in the area before the opening wedge, and the second set of driving rollers seizes the paper strip in the area between or after the opening wedges. 
     Moreover, it is advantageous if the first set of driving rollers and the second set of driving rollers can be driven in such a manner that, for separating the cushioning product into two areas, the first set of driving rollers can be slowed or stopped, and the second set of driving rollers can continue to be driven. As a result, a separation of the cushioning product by means of the two sets of rollers, which produce a crumpling, can be achieved in a simple manner. 
     The aim mentioned at the start is also achieved by a cushioning product which can be produced in particular by a method according to the invention and/or in particular by a device according to the invention. Such a cushioning product is produced from a longitudinal, two- or multilayered paper strip, wherein the individual layers are connected to one another in at least some sections in a middle area extending in the longitudinal direction, and wherein the individual layers comprise marginal areas which are not connected to one another, wherein the adjacent marginal areas are opened in the shape of a star, and the paper strip is crumpled at least along the middle area. Such a paper strip can be produced in a simple manner and it nevertheless presents positive cushioning properties. 
    
    
     
       Additional advantages and advantageous embodiments of the invention can be obtained from the following description in reference to which an embodiment of the example is described and explained in further detail. 
         FIG. 1  shows a flat paper strip for producing a cushioning product according to the invention in a perspective view; 
         FIG. 2  shows the paper strip according to  FIG. 1  in a top view; 
         FIG. 3  shows a perspective view of a device according to the invention for producing a cushioning product; 
         FIG. 4  shows the device according to  FIG. 3  in a side view; 
         FIG. 5  shows the device according to  FIGS. 3 and 4  in cross section along line V in  FIG. 4 , and 
         FIG. 6  shows a cushioning device according to the invention. 
     
    
    
     The paper strip  10  shown in  FIGS. 1 and 2  comprises two layers  12  and  14 . The two layers  12 ,  14  lie on top of each other and have identical outer contours. They have a longitudinal format, wherein their middle longitudinal axis is marked with the reference numeral  16 . The paper strip  10  can be an “endless” long paper strip, which can, for example, be unrolled from a roll or removed from a stack. 
     The two layers  12 ,  14  are connected to one another in their middle area  18 , which extends along the middle longitudinal axis  16  in the paper strip represented in  FIGS. 1 and 2 . It is preferable for the two layers  12 ,  14  to be connected to one another by a bonded connection along the middle longitudinal axis  16 , in particular by gluing. 
     The two layers  12 ,  14  in addition comprise marginal areas  20 ,  21  and  22 ,  23  which are not connected to one another. The layer  12  thus comprises the two marginal areas  20 ,  21 . The layer  14  comprises the two marginal areas  22 ,  23 . The marginal area  20  of the layer  12  is here arranged adjacently to the marginal area  22  of the layer  14 . Similarly, the marginal area  21  of the layer  12  is arranged adjacently to the marginal area  23  of the layer  14 . In the flat state of the paper strip  10 , shown in  FIGS. 1 and 2 , the marginal areas  20  and  22  as well as the marginal areas  21  and  23  can be in mutual contact. These marginal areas  20 ,  21 ,  22 ,  23  are then opened to form rays  26 , as described further below. 
     As is apparent in particular from  FIG. 2 , the paper strip  10  comprises predetermined separation areas  24  which extend transversely to the longitudinal axis  16  and which are configured as perforations provided in the layers  20  and  22 . As a result, the paper strip  10  can be separated into two areas, along a predetermined separation place  24 , by tearing off in the longitudinal direction. 
     In  FIG. 3 , the paper strip  10  is represented as it is reshaped to make a cushioning product. For this purpose, the device  50  represented in  FIG. 3  is used. The device  50  comprises an inlet area  52 , in which a guide roller  56  is provided, which is arranged transversely to the longitudinal direction  54  extending along the middle longitudinal axis  16  of the paper strip  10 . The guide roller  56  is here arranged so it can be rotated about a rotation axis  58 , in particular in such manner that the endless paper strip  10  is guided over the guide roller  56  during the operation of the device  50 . 
     The device  50  comprises furthermore two opening cores  58  for opening the flat paper strip  10  to form a paper strip  10 ′ which has a star-shaped cross section. The device  50  furthermore comprises an outlet area  60 , in which one can clearly see the paper strip  10 ′ which has been opened to the shape of a star. 
     Furthermore, the device  50  comprises an advance mechanism  62  for moving the paper strip  10  in the device  50  as well as a crumpling mechanism  64  for crumpling the paper strip  10  or  10 ′ along the middle area  18 . 
     As is apparent from  FIGS. 3 and 5 , the opening cores  58  face one another and they are spaced apart from each other by the distance a in the transverse direction, that is perpendicularly to the longitudinal direction  54 . The dimension a is selected here in such a manner that the middle area  18  of the paper strip  10 , that is the area in which the two layers  12  and  14  are connected to one another, can be moved through, between the two opening cores  58 . It is apparent, particularly from  FIG. 5 , that the two opening cores  58  comprise wedge sections  66  that are directed toward one another in cross section. The two wedge sections here enclose an angle of approximately 75°. 
     Moreover, it is apparent from  FIGS. 3 and 4  that the opening cores  58  comprise opening sections  68  configured in the shape of a wedge in longitudinal section toward the inlet area  52 . During the operation of the device  50 , the paper strip  10  is opened in the marginal areas  20 ,  21 ,  22 ,  23  along the opening section  68 . 
     In order to ensure a reliable opening of the marginal areas  20 ,  21 ,  22 ,  23 , separating elements  70 , which can be seen particularly clearly in  FIGS. 3 and 4 , are positioned, against the longitudinal direction  54 , before the opening cores  68 . The separating elements  70  are designed as metal separation plates, and, in the embodiment example depicted in the figures, they are designed to form a single part with the opening cores  58 . At the end areas  72  away from the opening sections  68 , the separating elements  70  engage between the mutually adjacent marginal areas  20  and  22 , or  21  and  23 , of the paper strip  10 , so that the marginal areas  20 ,  21  and  22 ,  23 , during the operation of the device, can be opened reliably by the opening cores  58 . The advance mechanism  62  comprises a first set of driving rollers  74 ,  76 , which are shown clearly in  FIGS. 3 and 4 . The driving rollers  74 ,  76  are arranged one above the other and they seize the paper strip  10  respectively above and below the middle area  18  of the paper strip  10 . In the embodiment according to the figures, the driving roller  76  is driven by a motor  78  via a V-belt  80 . The roller  74  is applied at a low pre-tensioning against the roller  76 , so that the latter roller is also driven by the roller  76 . As mentioned, between the rollers  74  and  76 , the middle area  18  of the paper strip  10  is located, as can be seen in  FIG. 3 . 
     For crumpling the paper strip  10  along the middle area, a second set of driving rollers  82 ,  84  is provided, which is arranged after the first set of driving rollers  74 ,  76  in the longitudinal direction  54 . Like the first set of driving rollers  74 ,  76 , in the case of the second set of driving rollers  82   84 , the lower roller  84  is also driven via an additional electrical motor  78 , in particular via an additional V-belt  80 . The upper roller  82  is separated under pre-tensioning against the lower roller  84 , so that the latter also rotates when the roller  84  rotates. 
     As is apparent particularly in  FIG. 4 , the first set of driving rollers  74 ,  76  is located, in the longitudinal direction  54 , before the opening cores  58 , in particular in the area between the two separating elements  70 . As one can also see clearly in  FIG. 4 , the second set of driving rollers  82 ,  84  is located in the area between the two opening cores  54 . From  FIG. 5 , it becomes apparent that the driving rollers  82 ,  84  as well as the driving rollers  74 ,  76  have a width b which is slightly smaller than the separation a between the opening cores  58 . 
     The angular speed of the rollers  82 ,  84  of the second driving set can here be selected in such a manner that it is slightly lower than the angular speed of the driving rollers  74 ,  76  of the first set. As a result, a crumpling of the paper strip  10  in the middle area  18  in a crumpling area  86  is produced, wherein the crumpling area  86  is located between the two sets of rollers  74 ,  76  and  82 ,  84 . The paper strip  10  consequently leaves the device in the outlet area  60  as a cushioning product, which, on the one hand, is opened to the shape of a star, and, on the other hand, is crushed in particular in the middle area. It should be noted that, in  FIGS. 3 and 4 , the rollers  74 ,  76  and  82 ,  84  rotate at the same angular speed, so that the paper strip  10 ′ is not crumpled here. The paper strip  10 ′ which leaves the device  50  consequently comprises the middle area  18  which is guided through between the rollers  72 ,  74  and  82 ,  84 . This area  18  is followed by the marginal areas  20 ,  21 ,  22 ,  23  which are opened to the shape of a star by means of the cores  58 , that is to say the four “rays”  26  of the opened paper strip  10 ′. The middle area  18  here has a width which corresponds to the width b. It is conceivable to reduce the width b to a very small size, for example, a line. As described, for crumpling, the angular speed of the rollers  74 ,  76  is increased or that of the rollers  82 ,  84  is decreased. 
     As described, such a cushioning product can be produced in a simple manner, while nonetheless having advantageous cushioning properties. 
     Although, in the figures, a paper strip  10  is represented which has only two layers, it is also conceivable to use a paper strip which has three or more layers. The three or more layers are then connected to one another in the middle area  18 , or preferably in the area of the middle longitudinal axis  16 . Instead of two mutually facing opening cores  58 , advantageously a total of four or more opening cores are then used, which engage in the interstices between the respective adjacent marginal areas of the respective layers. 
     For separating the endless long paper strip  10  into different areas, it is advantageous to slow the first set of driving rollers  74 ,  76 , while the second set of driving rollers  82 ,  84  continues to be driven, so that a tearing off occurs along a predetermined separation area represented in  FIGS. 1 and 2 . 
     In  FIG. 6 , a crumpled paper strip  10 ″ produced by the device  50 , that is to say the finished cushioning product  88 , is depicted. One can clearly see the crumpled middle area  18  with its width b, to which the marginal areas  20 ,  21 ,  22 ,  23  or the rays  26  are connected.