Patent Publication Number: US-2022219856-A1

Title: Machine And Method For Roll-Packing Of Mattresses

Description:
FIELD OF THE INVENTION 
     The present invention relates to a roll-packing machine for packaging of mattresses and to a method of roll-packing a mattress. 
     BACKGROUND OF THE INVENTION 
     With respect to packaging mattresses, a known packaging technique is roll packing. In this case the finished mattress is rolled to form a compact roll. Bands, tape or an outer wrapping may then be used to hold the roll in its form during storage or shipment. The roll may be formed manually. Alternatively, the roll may be formed in an automated manner, using a roll-packing machine. As described in WO 2018/049812 A1, such roll-packing machine may use a substantially cylindrical rolling chamber formed of a plurality of rollers. 
     However, using a rolling chamber formed of a plurality of rollers may result in rather high complexity of the roll-packing machine, e.g., because the arrangement of the rollers needs to be adjustable in order to conform to the outer shape of the mattress roll being formed and to allow removal of the mattress roll from the rolling chamber. Further, there may also be a risk of the mattress getting jammed between the rollers. 
     Accordingly, there is a need for techniques which allow for efficiently for roll-packing mattresses. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a roll-packing machine according to claim  1  and to a method according to claim  12 . The dependent claims define further embodiments. 
     Accordingly, an embodiment of the invention provides a roll-packing machine for packaging a mattress. The roll-packing machine comprises a belt drive mechanism having a closed-loop belt. Further, the roll-packing machine comprises a feed mechanism configured to feed the mattress to the belt. The belt drive mechanism is configured to form an inner loop of the belt, to receive the mattress in the inner loop, and to roll the mattress by advancing the belt while the mattress is received in the inner loop. The inner loop of the belt may thus act as a rolling chamber for the mattress. 
     According to an embodiment, the belt may be a segmented belt, i.e., be formed of multiple segments joined to each other by hinge joints. Flexibility of the belt may thus be provided by the pivot joints, rather than by the material of the segments. In this way, the belt may be provided with sufficient intrinsic stability to maintain the inner loop, without requiring dedicated support structures for maintaining the shape of the inner loop. Rather, stability of the inner loop may be provided by a first and a second roller, between which the inner loop is formed, by tension of the belt, and by a force generated by the mattress which is being fed to a portion of the belt between the first roller and the second roller. 
     According to an embodiment, the belt drive mechanism is configured to adjust a size of the inner loop. In this way, different sizes of the finished mattress roll may be accommodated. Further, the size of the inner loop may be controlled in accordance with the diameter of the mattress roll while the mattress is being rolled. In particular, the belt drive mechanism may be configured to increase the size of the inner loop while the mattress is being rolled. 
     According to an embodiment, the belt drive mechanism comprises a first roller and a second roller, with the inner loop being formed between the first roller and the second roller. In this case, the belt drive mechanism may be configured to adjust the size of the inner loop by individually controlling rotation of the first roller and the second roller. For example, with respect to an advancement direction of the belt, the first roller may be arranged upstream of the portion forming the inner loop, and the second roller may be arranged downstream of the portion forming the inner loop, i.e., the belt may be advanced from the first roller towards the second roller. In this case, the size of the inner loop may be increased by rotating the first roller at a higher rate than the second roller. The different rates of rotation may be achieved by providing the first roller and the second roller with individually controllable drive mechanisms. In addition or as an alternative, the first roller and the second roller could be provided with individually controllable brake mechanisms. By individually controlling rotation of the first roller and the second roller, the size of the inner loop may be adjusted in a highly efficient manner, without requiring complex mechanical structures. 
     According to an embodiment, the roll packing machine further comprises a belt tensioning mechanism configured to control tension of the belt while adjusting the size of the inner loop. In this way, changes of the size of the inner loop may be compensated and the tension of the belt may be kept at a desired level. 
     According to an embodiment, the tensioning mechanism is configured to control the tension of the belt by adjusting a size of one or more additional loops of the belt. For example, the belt drive mechanism may comprise multiple rollers for guiding the belt. At least some of the rollers may form the one or more additional loops. The tensioning mechanism may then be configured to adjust the size of the one or more additional loops by displacing two or more of the rollers relative to each other. By using a higher number of the additional loops, a required displacement range may be reduced, which may be beneficial in view of space-requirements for the roll-packing machine. 
     According to an embodiment, the belt drive mechanism comprises a first roller and a second roller, with the inner loop being formed between the first roller and the second roller. In this case, the roll-packing machine may further comprises an ejection mechanism configured to eject the rolled mattress from the inner loop by displacing the first roller away from the second roller. Due to the displacement, the inner loop may be opened so as to enable release and removal of the finished mattress roll from the inner loop. In some cases, the displacement may even have the effect that the portion of the belt between the first roller and the second roller takes a substantially straight-line form, so that the finished mattress roll can be easily moved from the roll-packing machine by rolling along the belt and/or by advancing the belt. 
     According to an embodiment, the roll-packing machine is further configured to wrap the rolled mattress by feeding a wrapping material, e.g., a plastic film, into the inner loop with the rolled mattress and advancing the belt to rotate the rolled mattress in the inner loop and wrap the wrapping material around the rolled mattress. In this case, the advancement of the belt may pull the wrapping material into the space between the rolled mattress and the inner loop. As a result, wrapping of the rolled mattress and formation of the finished mattress roll may be achieved in a highly efficient manner and with only a limited number of additional components, e.g., for feeding the wrapping material into the loop and/or for welding the wrapping material. 
     According to an embodiment, the feed mechanism is configured to compress the mattress while feeding the mattress to the belt. In this way, formation of a more compact mattress roll can be achieved. 
     According to a further embodiment, a method of packaging a mattress is provided. The method may be performed by the above roll-packing machine. The method comprises feeding the mattress to a closed-loop belt of a belt drive mechanism, forming an inner loop of the belt, receiving the mattress in the inner loop, and rolling the mattress by advancing the belt while the mattress is received in the inner loop. As mentioned above, the belt may be a segmented belt. 
     According to an embodiment, the method further comprises adjusting the size of the inner loop while the mattress is being rolled, e.g., by increasing the size of the inner loop so as to accommodate an increasing diameter of the mattress roll being formed. 
     According to an embodiment, the method further comprises wrapping the rolled mattress by feeding a wrapping material, e.g., a plastic film, into the inner loop with the rolled mattress and advancing the belt to rotate the rolled mattress in the inner loop and wrap the wrapping material around the rolled mattress. In this case, the advancement of the belt may pull the wrapping material into the space between the rolled mattress and the inner loop. As a result, wrapping of the rolled mattress and formation of the finished mattress roll may be achieved in a highly efficient manner. 
     According to an embodiment, the belt drive mechanism comprises a first roller and a second roller, with the inner loop being formed between the first roller and the second roller. In this case, the method may further comprise ejecting the rolled mattress from the inner loop by displacing the first roller away from the second roller. Due to the displacement, the inner loop may be opened so as to enable release and removal of the finished mattress roll from the inner loop. In some cases, the displacement may have the effect that the portion of the belt between the first roller and the second roller takes a substantially straight-line form, so that the finished mattress roll can be moved from the roll-packing machine by rolling along the belt and/or by advancing the belt. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Embodiments of the invention will be described with reference to the accompanying drawings. 
         FIG. 1A  illustrates a mattress to be roll-packed according to an embodiment. 
         FIG. 1B  illustrates a mattress roll as produced according to an embodiment. 
         FIG. 2  schematically illustrates a sectional view of a roll-packing machine according to an embodiment. 
         FIG. 3  schematically illustrates a sectional view of a roll-packing machine according to a further embodiment. 
         FIGS. 4A and 4B  schematically illustrates elements of a segmented belt as utilized in a roll-packing machine according to an embodiment. 
         FIGS. 5A-5H  schematically illustrate different stages of a roll-packing process according to an embodiment. 
         FIG. 6  shows a flowchart for illustrating a method according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Exemplary embodiments of the invention will be described with reference to the drawings. In particular, a roll-packing machine and a roll-packing method for mattresses will be described. While the following detailed description refers to packaging of mattresses as typically used for bedding furniture, it is to be understood that the illustrated concepts are not limited to this type of mattress, but for example could also be applied to other types mattress, e.g., like used in other types of furniture or even in applications not related to furniture, e.g., mattresses as used for sports or as components of buildings or vehicles. The mattresses may for example be based on foam material, one or more innerspring units, e.g., based on pocketed springs or a combination of pocketed springs and wire framework elements, or on a combination of a foam material and one or more innerspring units. The roll-packing machine and the method of the illustrated concepts are used for packaging the mattress by rolling, thereby forming a mattress roll which includes the rolled mattress and optionally also and outer wrapping around the rolled mattress. In some cases, the mattress may also be wrapped before being rolled, i.e., which means that the mattress roll may also include an inner wrapping formed around the mattress itself. It is noted that the features of different embodiments may be combined with each other unless specifically stated otherwise. 
       FIG. 1A  shows a sectional view for schematically illustrating a mattress  10 . As mentioned above, the mattress  10  may be a mattress for bedding applications. The mattress may for example be based on foam material and/or on one or more innerspring units. If present, such innerspring unit may be based on pocketed springs or a combination of pocketed springs and wire framework elements. The mattress may have a substantially box-shaped outer form, with a typical length being in the range of 100 cm to 250 cm, a typical width being in the range of 60 cm to 200 cm, and a typical thickness being in the range of 5 cm to 30 cm. The mattress  10  is assumed to be compressible in the thickness direction. 
       FIG. 1B  illustrates a mattress roll  20  which includes the rolled mattress  10  and an outer wrapping  25  enclosing the rolled mattress  10 . The outer wrapping may for example be formed of one or more layers of a plastic film. The outer wrapping  25  ensures that the mattress  10  stays in the rolled state and thus keeps the mattress roll stable, e.g., during storage or transport. A typical outer diameter of the mattress roll is in the range of 30 cm to 80 cm, more specifically in the range of 40 cm to 60 cm. For forming the mattress roll  20 , the mattress  10  is typically rolled around an axis parallel to its width direction. In some cases, an additional wrapping or other type of cover layer may also be provided on the mattress  10  before being rolled, resulting in the formation of inner layers of wrapping or cover material also in between the windings of the mattress roll  20 . 
       FIG. 2  shows a sectional view for schematically illustrating a roll-packing machine  100  which may be used for automated roll-packing of mattresses. In the following explanations, it is assumed that the roll-packing machine  100  is used for roll packing the mattress  10 , thereby producing the mattress roll  20 . In  FIG. 2 , a first horizontal direction is denoted by “x”, and a vertical direction is denoted by “z”. A second horizontal direction, extending perpendicular to the x-direction and the y-direction, i.e., perpendicular to the drawing plane, is denoted by “y”. In the illustrated example, the roll-packing machine  100  is configured to perform a roll-packing process involving rolling of the mattress  10  around an axis in the y-direction. 
     As illustrated, the roll-packing machine  100  is provided with a belt-drive mechanism with a closed-loop belt  110  which is guided by rollers  121 ,  122 ,  123 ,  124 ,  125 ,  126 . Rotational axes of the rollers  121 ,  122 ,  123 ,  124 ,  125 ,  126  extend in the y-direction. In the illustrated example, the belt  110  is assumed to be driven by the rollers  121  and  122 . For this purpose, the rollers  121 ,  122  are provided with individually controllable drive mechanisms, e.g., respectively based on an electric motor coupled to a rotation shaft of the roller  121 ,  122 . An advancement direction of the belt  110  is illustrated by arrows A. 
     As further illustrated, the belt drive mechanism is configured to form an inner loop  115  of the belt  110 . As will be further explained below, the inner loop  115  acts as a rolling chamber for rolling the mattress  10 . The inner loop  115  is formed in a portion of the belt  110  between the roller  121  and the roller  122 . A size of the loop  115 , i.e., the length of the portion of the belt  110  between the roller  121  and the roller  122 , can be adjusted by individually controlling rotation of the roller  121  and the roller  122 . When for example assuming an advancement of the belt  110  in the direction of the arrows A, the size of the loop  115  can be increased by controlling the roller  121  to rotate faster than the roller  122 . Similarly, the size of the loop  115  can be decreased by controlling the roller  121  to rotate slower than the roller  122 . Since the rollers  121 ,  122  are located at an entry into the inner loop  115 , the rollers  121 ,  122  may also be referred to as entry rollers. 
     In the illustrated example, the roll-packing machine  100  is further provided with a tensioning mechanism for controlling tension of the belt  110 . By means of the tensioning mechanism, the tension of the belt  110  can be maintained at a desired level, even when changing the size of the inner loop  115 . In the example of  FIG. 2 , the tensioning mechanism includes a drive mechanism  150  for displacing the roller  124  of the belt drive mechanism with respect to other rollers  123  of the belt drive mechanism. The displacement of the roller  124  is illustrated by arrow B. By the displacement of the roller  124 , a size of an additional loop of the belt  110 , which is formed by the rollers  123 ,  124 , and  125 , can be adjusted. Specifically, the size of the additional loop can be set in such a way that it compensates changes of the size of the inner loop  115 . For example, while increasing the size of the inner loop  115 , the required additional length of the belt portion forming the inner loop  115  can be provided by reducing the size of the additional loop formed by the rollers  123 ,  124 , and  125 . 
     In the illustrated example, the roll-packing machine  100  is further provided with an ejection mechanism for allowing release and removal of the finished mattress roll  20  from the inner loop  115 . In the illustrated example, the ejection mechanism is based on a drive mechanism which displaces the entry roller  121  away from the entry roller  122 . In the example of  FIG. 2 , the rollers  121  and  126  of the belt drive mechanism are mounted on a tiltable support structure  155 . By tilting the support structure as illustrated by arrow C, the entry roller  121  can be moved away from the entry roller  122 , resulting in the inner loop  115  being opened, so that the mattress roll  20  formed in the inner loop  115  is released and can be removed. 
     In the illustrated example, the roll-packing machine  100  is further provided with a wrapping mechanism  160  for wrapping the rolled mattress  10  with a wrapping material, thereby forming the outer wrapping  25 . In the illustrated example, the wrapping mechanism  160  is configured to introduce the wrapping material  25 , which is supplied from a supply roll  161 , into the inner loop  115  with the rolled mattress  10 . A tool  162  may then be used for cutting and/or welding the wrapping material wrapped around the rolled mattress  10 . 
     The roll-packing machine  100  further includes a feed mechanism for feeding the mattress  10  to the belt  110 , in particular to the portion of the belt  110  between the entry rollers  121 ,  122 . In the illustrated example, the feed mechanism includes a lower conveyor belt mechanism  130  and an upper conveyor belt mechanism  140 . The lower conveyor belt mechanism  130  includes a belt  131  guided by rollers  132 ,  133 ,  134 . One of the rollers  132 ,  133 ,  134 , e.g., the roller  132 , may be used for driving the belt  131 . The upper conveyor belt mechanism  140  includes a belt  141  guided by rollers  142 ,  143 . One of the rollers  142 ,  143 , e.g., the roller  143 , may be used for driving the belt  131 . The mattress  10  is conveyed by advancing the lower conveyor belt mechanism  130  and the upper conveyor belt mechanism  140  in a direction as illustrated by arrow D. The feed mechanism may be opened for receiving the mattress. In the illustrated example, this is achieved by a drive mechanism  145  which displaces the roller  142  in a direction as illustrated by arrow D. By means of the drive mechanism  145  a part of the upper conveyor belt mechanism  140  may be moved away from the lower conveyor belt mechanism drive  130  to facilitate insertion of the mattress in an initial stage of the roll-packing process. After inserting the mattress  10 , the drive mechanism  145  may be used to move the upper conveyor belt mechanism  140  toward the lower conveyor belt mechanism  130  so that the mattress  10  is sandwiched between the belt  131  of the lower conveyor belt mechanism  130  and the belt  141  of the upper conveyor belt mechanism  140 . In some scenarios, this may also result in compression of the mattress  10  between the lower conveyor belt mechanism  130  and the upper conveyor belt mechanism  140 . The distance between the lower conveyor belt mechanism  130  and the upper conveyor belt mechanism  140  may be adjustable to accommodate different mattress thicknesses and/or to adjust a degree of compression of the mattress  10 . 
       FIG. 3  shows a sectional view for schematically illustrating a further roll-packing machine  100 ′ which may be used for automated roll-packing of mattresses, e.g., for roll packing the mattress  10 , thereby producing the mattress roll  20 . Similar to  FIG. 2 , in  FIG. 3  a first horizontal direction is denoted by “x”, and a vertical direction is denoted by “z”. A second horizontal direction, extending perpendicular to the x-direction and the y-direction, i.e., perpendicular to the drawing plane, is denoted by “y”. In the illustrated example, the roll-packing machine  100 ′ is configured to perform a roll-packing process involving rolling of the mattress  10  around an axis in the y-direction. 
     In many aspects, the roll-packing machine  100 ′ of  FIG. 3  is similar to that of  FIG. 2 , and corresponding components of the roll-packing machine  100  and the roll-packing machine  100 ′ are denoted by the same reference numerals. Further details concerning structure and functionality of these components in the roll-packing machine  100 ′ can be taken from the description in connection with  FIG. 2 . 
     The roll-packing machine  100 ′ differs from the roll-packing machine  100  in that the belt drive mechanism includes more additional loops for controlling the tension of the belt  110 . In the roll-packing machine  100 , the belt-drive mechanism includes rollers  121 ,  122 ,  123 A,  123 B,  123 C,  124 ,  125 , and  126  for guiding the belt  110 . The rollers  121 ,  122 ,  124 ,  125 , and  126  are similar to the rollers  121 ,  122 ,  124 ,  125 , and  126  in the roll-packing machine  100 . The rollers  123 A,  123 B,  123 C replace the roller  123  of the roll-packing machine  100 , thereby forming two additional loops (two outer loop, one inner loop) of the belt  100 . 
     In the roll-packing machine  100 ′ the tensioning mechanism for controlling tension of the belt  110  includes a drive mechanism  150 ′ for displacing the rollers  123 B and  124  of the belt drive mechanism with respect to other rollers of the belt drive mechanism. The displacement of the roller  123 B,  124  is illustrated by arrows B. By the displacement of the rollers  123 B,  124 , the sizes of the additional loop of the belt  110 , which are formed by the rollers  123 A,  123 B,  123 C,  124 , and  125 , can be adjusted. Specifically, the sizes of the additional loops can be set in such a way that they compensate changes of the size of the inner loop  115 . For example, while increasing the size of the inner loop  115 , the required additional length of the belt portion forming the inner loop  115  can be provided by reducing the sizes of the additional loops formed by the rollers  123 A,  123 B,  123 C,  124 , and  125 . In the roll-packing machine  100 ′, the required range of displacement of the rollers  123 B,  124  is lower than the required range of displacement of the roller  124  in the roll-packing machine  100 . This may for example allow for a reduced space requirement of the roll-packing machine  100 ′, e.g., in terms of a dimension of the roll-packing machine  100 ′ in the x-direction. 
       FIGS. 4A and 4B  further illustrate an implementation of the belt  110  which may be used in the roll-packing machine  100  or the roll-packing machine  100 ′. More specifically,  FIG. 4A  shows a top view of a part of the belt  110 , and  FIG. 4B  shows a side view of a part of the belt  110 . In  FIGS. 4A and 4B , a length direction of the belt  110  (along which the belt  110  is advanced in operation of the roll-packing machine  100 ,  100 ′) is denoted by L, a width direction of the belt  110  (parallel to the axis of rolling the mattress  10 ) is denoted by W, and a thickness direction of the belt  110  is denoted by T. 
     In the illustrated example, the belt  110  is implemented as a segmented belt, i.e., formed of multiple segments  111 ,  112 ,  113 ,  114  which are joined together by hinged couplings. The segments  111 ,  112 ,  113 ,  114  themselves are assumed to be relatively rigid, with deformation of the segments  111 ,  112 ,  113 ,  114  during operation of the roll-packing machine  100 ,  100 ′ being negligible. Flexibility of the belt  110  may thus be provided by the hinged joints couplings between the segments  111 ,  112 ,  113 ,  114 , rather than by the material of the segments  111 ,  112 ,  113 ,  114 . In this way, the belt may be provided with sufficient intrinsic stability to maintain the inner loop  115 , without requiring dedicated support structures for maintaining the shape of the inner loop  115 . Rather, stability of the inner loop may be provided by the entry rollers  121 ,  122 , between which the inner loop  115  is formed, by the tension of the belt  110 , and by a force generated by the mattress  10  which is being fed into the inner loop  115  and urges the inner loop  115  to expand. However, it is noted that while dedicated support structures may not be required, such support structures could nonetheless be present, e.g., in order to confine the inner loop  115  to a certain space or to avoid contact of the inner loop with other parts of the roll-packing machine  100 ,  100 ′. 
     The segments  111 ,  112 ,  113 ,  114  of the belt  110  may be formed of a plastic material. In this way, excessive weight of the belt  110  may be avoided while at the same time ensuring sufficient rigidity of the segments  111 ,  112 ,  113 ,  114 . On a side facing the mattress  10  The segments  111 ,  112 ,  113 ,  114  may be provided with a surface material and/or a surface structure (in  FIG. 4A  indicated by cross-hatched regions) to provide a desired level of grip of the mattress  10  on the belt  110 . For example, the segments  111 ,  112 ,  113 ,  114  could be provided with rubber elements which form or cover the cross-hatched regions. As illustrated, each of the segments  111 ,  112 ,  113 ,  114  may be composed from multiple sub-segments  111 A,  111 B,  112 A,  112 B,  112 C joined together along the width direction W. However, a single-piece configuration of each of the segments  111 ,  112 ,  113 ,  114  would be possible as well. In some scenarios, also the conveyor belt  131  and/or the conveyor belt  141  of the feed mechanism could be implemented as a segmented belt, e.g., with similar characteristics as explained in connection with  FIGS. 4A and 4B . 
       FIGS. 5A-5H  further illustrate the roll-packing process. While  FIGS. 5A-5H  assume a configuration of the roll-packing machine  100  as illustrated in  FIG. 2 , it is noted that a similar process could also be implemented using a configuration with more additional loops of the belt  110 , e.g., using a configuration of the roll-packing machine  100 ′ as illustrated in  FIG. 3 . 
       FIG. 5A  illustrates an initial stage of the roll-packing process, in which the mattress  10  is inserted into the feed mechanism of the roll-packing machine  100 . In this initial stage of the roll-packing process, the inner loop  115  of the belt  110  is absent or has only a small size. As illustrated, the mattress is placed on the lower conveyor belt mechanism  130 , and the upper conveyor belt mechanism  140  is then lowered to sandwich the mattress  10  between the lower conveyor belt mechanism  130  and the upper conveyor belt mechanism  140 . If desired, the mattress  10  may also be compressed between the lower conveyor belt mechanism  130  and the upper conveyor belt mechanism  140 . 
       FIG. 5B  illustrates a next stage of the roll-packing process, in which the mattress  10  is sandwiched, and optionally compressed, between the lower conveyor belt mechanism  130  and the upper conveyor belt mechanism  140 . In this stage, the conveyor belt mechanisms  130 ,  140  are operated to convey the mattress  10  toward the portion of the belt  110  between the entry rollers  121 ,  122  until the mattress  10  eventually makes contact with the belt  110 . 
       FIG. 5C  illustrates a next stage of the roll-packing process, in which the mattress  10  has made contact with the belt  110 . In this stage, the conveyor belt mechanisms  130 ,  140  are operated to further convey the mattress  10  toward the portion of the belt  110  between the entry rollers  121 ,  122 . The mattress  10  exerts an inward force onto the belt  110 . At the same time the belt  110  is advanced. The advancing belt  110  grips the end of the mattress  10  and pulls it toward the entry roller  122 , thereby initiating rolling of the mattress  10 . By controlling the roller  121  to rotate at a higher rate than the roller  122 , the inner loop  115  is allowed to expanding under the force exerted by the mattress  10 , as illustrated in  FIG. 5D . 
     As illustrated by  FIGS. 5D to 5F , the process of advancing the belt  110  while feeding the mattress  10  to the expanding inner loop  115  continues until the mattress  10  is fully received in the inner loop  115 . As illustrated in  FIG. 5F , this may result in the mattress  10  being rolled in multiple spiral-like windings. The additional belt length required for expansion of the inner loop  115  is provided by moving the roller  124  towards the roller  125 , thereby reducing the size of the additional loop formed by the rollers  123 ,  124 , and  125 . 
       FIG. 5G  illustrates a next stage of the roll-packing process, in which the fully rolled mattress  10  is wrapped with the wrapping material to form the mattress roll  20  with the outer wrapping  25 . This is achieved by providing the wrapping material from the supply roll  161  into the inner loop  115  with the rolled mattress  10 , while continuing to advance the belt  110 . This causes rotation of the rolled mattress  10  in the inner loop  115 , with the wrapping material being pulled in between the belt  110  and the rolled mattress  10 . By completing one or more rotations of the rolled mattress  10  in the inner loop  115 , the rolled mattress  10  is wrapped with one or more layers of the wrapping material. The cutting/welding tool  162  may then be used to cut the wrapping material and weld or otherwise fixate the wrapping material around the rolled mattress  20 . At this point, the mattress roll is finished, but still enclosed in the inner loop  115 . 
       FIG. 5H  illustrates a next stage of the roll-packing process, in which the finished mattress roll  20  is ejected from the inner loop  115  and the roll-packing machine  100 . This is achieved by tilting the support structure  155 , thereby moving the entry roller  122  away from the entry roller  121 . The movement of the entry roller  122  opens the inner loop  115  so that the mattress roll  20  is released and can be removed. As illustrated in  FIG. 5H  the movement of the entry roller  122  may cause that the portion of the belt  110  between the entry rollers assumes a straight-line form so that the mattress roll  20  can be removed from the roll-packing machine  100  by rolling along the belt  110 . This rolling of the mattress roll  20  can be facilitated by moving the entry roller  122  to a lower vertical position than the entry roller  121 , so that rolling of the mattress roll  20  from the roll-packing machine  100  can be driven or at least assisted by gravity force. Alternatively or in addition, removal of the mattress roll  20  from the roll-packing machine  100  could be accomplished by driving the belt  110  to convey the mattress roll  20  from the roll-packing machine  100 . For example, in the situation illustrated in  FIG. 5H , the belt  110  could be driven oppositely to the above-mentioned advancement direction A used during rolling of the mattress  10 . When moving the entry roller  122  away from the entry roller  121  a decrease of the length of the belt portion between the entry rollers  121 ,  122  may be compensated by moving the roller  124  back away from the roller  125 . 
       FIG. 6  shows a flowchart for illustrating a method of roll-packing a mattress, e.g., the above-mentioned mattress  10 . The method of  FIG. 6  may be used to implement the above-described concepts and may be performed by a roll-packing machine, e.g., the above roll-packing machine  100  or  100 ′. 
     At block  610  the mattress is fed to a closed-loop belt of a belt drive mechanism, e.g., a belt drive mechanism as described in connection with  FIG. 2  or a belt drive mechanism as described in connection with  FIG. 3 . The belt may be a segmented belt, e.g., as described in connection with  FIGS. 4A and 4B  for the belt  110 . The feeding of the mattress may be performed by a feed mechanism, e.g., a feed mechanism based on one or more conveyor belt mechanisms as illustrated in  FIGS. 2 and 3 . In some scenarios, the mattress may be compressed while being fed to the belt. 
     At block  620 , an inner loop of the belt is formed, e.g., like the above-mentioned inner loop  115 . An example of the formation of the inner loop is illustrated in  FIGS. 5C and 5D , and at block  630 , the mattress is received in the inner loop, e.g., as illustrated by  FIGS. 5C to 5E . As explained above, the belt drive mechanism may be provided with a first roller and a second roller between which the inner loop is formed, e.g., the above-mentioned entry rollers  121 ,  122 . Formation of the inner loop may then involve individually controlling rotation of the first roller and the second roller. Specifically, by controlling the first roller and the second roller to rotate at different rates, the inner loop may be formed while the mattress fed to the belt exerts an inward force onto the belt. 
     At block  640  the mattress is rolled by advancing the belt while the mattress is received in the inner loop, e.g., as illustrated in  FIGS. 5C to 5F . In some scenarios, this may involve adjusting the size of the inner loop while the mattress is being rolled. As explained above, the belt drive mechanism may be provided with a first roller and a second roller between which the inner loop is formed, e.g., the above-mentioned entry rollers  121 ,  122 . Adjusting the size of the inner loop may then involve individually controlling rotation of the first roller and the second roller. Specifically, by controlling the first roller and the second roller to rotate at different rates, the size of the inner loop may be increased in accordance with an increase of the diameter of the rolled mattress. 
     At optional block  650 , the rolled mattress is wrapped. This may involve feeding a wrapping material into the inner loop with the rolled mattress and advancing the belt to rotate the rolled mattress in the inner loop and wrap the wrapping material around the rolled mattress. An example of such wrapping process is described in connection with  FIG. 5G . 
     At optional block  660 , the rolled mattress is ejected from the inner loop. As explained above, the belt drive mechanism may be provided with a first roller and a second roller between which the inner loop is formed, e.g., the above-mentioned entry rollers  121 ,  122 . Ejecting the rolled mattress may then involve displacing the first roller away from the second roller. An example of such ejection process is described in connection with  FIG. 5H . 
     It is noted that the flowchart of  FIG. 6  is not intended to imply a strict order of the illustrated actions and that the illustrated actions may for example overlap or be otherwise combined with each other. 
     It is to be understood that the illustrated roll-packing machine  100 ,  100 ′ and its operations are susceptible to various modifications, without departing from the illustrated concepts. For example, the geometry, number and arrangement of rolls in the belt-drive mechanism could be varied. Further, various types of feed mechanisms could be used for feeding the mattress to the belt and into the inner loop, e.g., feed mechanisms based on conveyor rollers or conveyor wheels. Still further, other way of fixating the mattress roll  20  could be used in addition or as an alternative to the outer wrapping  25 , e.g., fixation by welding a wrapping present on the mattress  10  itself or fixation by using one or more strings or bands around the rolled mattress  10 .