Patent Publication Number: US-10780334-B2

Title: Zippered safety layer in a trampoline

Description:
FIELD 
     Embodiments of the invention relate to a zipper attached safety layer applied between a flexible trampoline mat and the trampoline&#39;s edge pad. Embodiments of the invention further relate to a trampoline comprising such a zippered safety layer and to a method of arranging the safety layer in a trampoline. 
     BACKGROUND 
     The following description includes information that may be useful in understanding embodiments of the invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art. 
     The modern trampoline era began in the mid-1930s, see, e.g., U.S. Pat. No. 2,370,990 by George Nissen who with Larry Griswold was instrumental in developing the modern trampoline. Even though trampolines were initially developed for competitive or professional purposes, trampolines for recreational use are nowadays popular home entertainment accessories. 
     A trampoline comprises a flexible mat, a frame, and at least one resilient member. The flexible mat is typically circular, oval, square, or rectangular. The flexible mat may comprise a cloth or net-shaped structure. It may be made of a polymeric material, such as polypropylene. The frame, conventionally made of metal, encompasses the flexible mat and typically has substantially the same shape as the flexible mat. A circular or oval mat is typically surrounded by a circular or oval frame having a larger diameter than the flexible mat, and a square or rectangular mat is typically surrounded by a substantially square or rectangular frame, which however may comprise rounded-off edges. 
     The flexible mat typically comprises a plurality of attachments distributed along the mat&#39;s edge. The attachments are adapted to receive one or more resilient members for retaining the flexible mat under tension, creating a suspension system. The resilient members may comprise a plurality of springs (e.g. helical springs) that connect the edge of the flexible mat to the frame, thereby tensioning the flexible mat. When a person is using the flexible mat, i.e. jumping on it, the springs will extend in length and thereafter strive to return to their resting length. The spring may be attached to a loop, such as a D-shaped or triangle shaped ring, comprised in the flexible mat by means of a hook that attaches to the spring. Thus, the system of loops and D-rings comprise the plurality of attachments for the flexible mat to receive the resilient members. 
     In some trampoline embodiments, the resilient member may comprise an elastic cord. Normally, the elastic cord is long enough to go back and forth between the edge of the flexible mat and the frame several times. Each portion connecting the flexible mat to the frame then forms a segment, which correspond to a spring in the above example. The elastic cord may be so long, that only one elastic cord is utilized for the whole mat, or a plurality of elastic cords may be used. 
     The flexible mat is conventionally surrounded by an edge pad, which is adapted to at least partly cover the at least one resilient member and/or the frame. The edge pad helps prevent users from stepping or landing between the resilient members, e.g. when climbing onto the flexible mat. The edge pad may also be arranged to cover the frame, thereby reducing a possible impact with the frame in case of stepping or landing on the frame. The edge pad is often made as a number of segments, the shapes of which are adapted to the frame and the flexible mat. For a circular or oval mat, the segments may therefore be arc-shaped. For a square or rectangular mat, rectangular segments may be used. 
     While safety has improved in trampolines in recent years, there nevertheless exists a continuous need to improve safety in the trampoline arts, especially where such improvements can be accomplished in a commercially reasonable fashion. 
     SUMMARY OF THE INVENTION 
     Embodiments of the invention provide a trampoline, comprising a frame, a flexible mat, and a plurality of resilient members attached to the frame and to the flexible mat, wherein the resilient members receive kinetic energy from a user jumping on the flexible mat, causing the user to be lifted above the surface of the flexible mat. The trampoline also includes an edge pad that rests on an upper surface of the frame and extending to the flexible mat, wherein the edge pad includes a material to absorb shock from a user falling on the edge pad and a safety layer removably attached to at least one of the edge pad and the flexible mat, wherein the safety layer seals off open spaces between the edge pad and the flexible mat to prevent user bodily appendages from engaging a resilient member of the plurality of resilient members. 
     Embodiments of the invention provide a method for assembling a trampoline that comprises attaching a flexible mat to a frame using a plurality of resilient members, wherein the resilient members receive kinetic energy from a user jumping on the flexible mat, causing the user to be lifted above the surface of the flexible mat. The method further comprises attaching an edge pad resting on an upper surface of the frame and extending to the flexible mat, wherein the edge pad includes a material to absorb shock from a user falling on the edge pad. The method also comprises removably attaching a safety layer to at least one of the edge pad and the flexible mat, wherein the safety layer seals off open spaces between the edge pad and the flexible mat to prevent user bodily appendages from engaging a resilient member of the plurality of resilient members. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the invention will be further explained by means of non-limiting examples with reference to the appended drawings. Figures provided herein may or may not be provided to scale. The relative dimensions or proportions may vary. It should be noted that the dimensions of some features of the present invention may have been exaggerated for the sake of clarity. 
         FIG. 1  illustrates a conventional trampoline  100  comprising a flexible mat  106 , a frame  111 , a plurality of resilient members  109 , illustrated as helical springs, and an edge pad  103 . 
         FIGS. 2A and 2B  illustrate a safety layer  205  in a trampoline  200 , according to an embodiment of the invention. 
         FIG. 3  illustrates the safety layer  205  in a trampoline  200  from another point of view, according to an embodiment of the invention. 
         FIG. 4  illustrates a safety layer  405  in a trampoline  400 , according to an alternative embodiment of the invention. 
         FIG. 5  illustrates a safety layer  505  in a trampoline  500 , according to an alternative embodiment of the invention. 
         FIG. 6  illustrates a safety layer  605  in a trampoline  600 , according to an alternative embodiment of the invention. 
         FIG. 7  illustrates a trampoline  700 , according an embodiment of the invention. 
         FIG. 8  illustrates a trampoline  800 , according to an embodiment of the invention. 
         FIG. 9  illustrates a trampoline  900 , according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION 
     Embodiments of the invention provide a safety layer interposed between the flexible trampoline mat and the trampoline&#39;s edge pad. The safety layer seals off the flexible mat and edge pad from the user and the user&#39;s bodily appendages (e.g., head, foot, fingers, toes, etc.) and has sufficient flexibility to expand and contract as the user jumps up and down on the trampoline. Thus, the safety layer improves overall safety for the trampoline by preventing the user from inserting a bodily appendage (e.g., head, foot, hand) between the flexible mat and edge pad and dangerously engaging with the trampoline&#39;s suspension system. The safety layer may be removably attached to either the flexible mat and/or the edge pad using a zipper such that the safety layer may be easily attached and easily removed, according to an embodiment of the invention. 
     The safety problem solved by the safety layer can be shown by the conventional trampoline depicted in  FIG. 1 . As shown in  FIG. 1 , a conventional trampoline  100  comprises a flexible mat  106 , a frame  111 , a plurality of resilient members  109 , illustrated as helical springs, and an edge pad  103 . A portion of the edge pad  103  has been removed to show the resilient members  109 . The frame  111  is supported by a plurality of legs  121 . 
     The resilient members  109  comprise a suspension system between the flexible mat  106  and the frame  111  for the trampoline  100 . Trampoline users jump or bounce on the flexible mat  106  in a vertical direction D 1  and possibly also move in a horizontal direction D 2  perpendicular to the first direction D 1 . The edge pad  103  lies on top of the suspension system comprising the resilient members  109  to protect trampoline users from harm as they jump on the flexible mat  106  since they could possibly land on the suspension system and become injured. The fabric of the flexible mat  106  that users jump or bounce on is often not elastic itself, instead the resilient members  109  (e.g., helical springs) provide the elasticity which creates the potential energy. The edge pad  103  generally serves to reduce the severity of impact injuries. 
     However, a safety problem resides in the design of trampoline  100  because some users, especially children, may accidentally place a bodily appendage (e.g., their feet, head, or hands) between the flexible mat  106  and the edge pad  103  and contact the suspension system comprising the resilient members  109 . For example, if a user is bouncing particularly high on the flexible mat  106 , causing the resilient members  109  to flex, then a user&#39;s bodily appendage (e.g., a hand or foot) landing on the resilient members  109  could cause a painful and harmful pinch to the user&#39;s bodily appendage as the resilient members  109  contract while returning to their resting position. Trampoline users tend to increasingly lose control of their bodily motions as they impart increasing amounts of energy to the trampoline&#39;s suspension system, thus increasing the chance of an accident such as falling and accidentally slipping a hand or foot into the suspension system. 
     To prevent user bodily appendages from coming into contact with the resilient members of the suspension system, the edge pad  103  should be attached to the flexible mat  106 , according to an embodiment of the invention. These two parts could be sewn or glued together but such a connection would complicate maintenance and transportation of the trampoline. In addition, directly attaching the edge pad  103  to the flexible mat  106  could cause problems as the trampoline user jumps up and down on the flexible mat  106  due to a loss of flexibility between the flexible mat  106  and the edge pad  103 . In such situations, the increased strain could cause tearing of one the flexible mat  106 , the edge pad  103 , and/or the attachment between them. 
     Accordingly, an embodiment of the invention comprises attaching the edge pad to the flexible using a removably attachable safety layer. The safety layer may expand and contract as the user jumps up and down on the trampoline, avoiding a build-up of excess tension in the edge pad and/or the flexible mat. The removably attachable safety layer may comprise a piece that directly attaches between the flexible mat and the edge pad to prevent the user from accidentally touching the suspension system while providing an appropriately level of flexibility for continued operations of the trampoline. 
     The safety layer may be removably attached to one or both sides of the flexible mat and edge pad, according to various embodiments of the invention. These embodiments aim to simplify trampoline assembly for end user customers and/or maintenance personnel. 
       FIGS. 2A and 2B  illustrate a close-up view of a safety layer  205  in a trampoline  200 , according to an embodiment of the invention. ( FIG. 8  provides an exemplary embodiment of an entire trampoline  800  suitable for application of a safety layer, such as the safety layer  205 ).  FIG. 2A  illustrates the trampoline  200  shown from a top side (e.g., the side that user bounces on) while  FIG. 2B  illustrates the trampoline  200  shown from a bottom side. 
     A zipper  201  attaches the safety layer  205  to the flexible mat  206 , and a zipper  202  attaches the safety layer  205  to the edge pad  203 , according to an embodiment of the invention. The edge pad  203  and the flexible mat  206  have similar functions to the edge pad  103  and the flexible mat  106  shown in  FIG. 1 . The zipper  201  typically surrounds the flexible mat  206 , and the zipper  202  typically surrounds the edge pad  203 , according to an embodiment of the invention. 
     As shown in  FIGS. 2A and 2B , the zipper  201  and the zipper  202  have not been pulled completely taught so as to reveal a spring  209  that comprises a resilient member and forms part of the trampoline suspension system shown in  FIG. 1 . To prevent the zipper  201  and/or the zipper  202  from coming open once closed, the zippers  201 ,  202  could each be fixed in a closed position with small padlocks whose shanks (or shackles) pass through an opening in the slider on each of the zippers  201 ,  202 . For example, the zipper  201  could be locked with a small padlock  234  that locks the zipper  201  in place to the safety layer  205  via an attachment point  233  (e.g., a loop), according to an embodiment of the invention. Similarly, to prevent the zipper  202  from coming open once closed, the zipper  202  could be locked in place with a small padlock  232  that attaches the zipper  201  to the safety layer  205  via an attachment point  231  (e.g. a loop), according to an embodiment of the invention. 
     The slider for the zipper  201  and the slider for the zipper  202  could be placed on either the top side or the bottom side of the flexible mat  206 , the edge pad  203 , and the safety layer  205 . As shown in  FIG. 2A , the sliders for the zippers  201 ,  202  are on the top (e.g., the user side) of the trampoline  200 , but the sliders for the zippers  201 ,  202  could alternatively be placed on the bottom side of the trampoline  200 , according to embodiment of the invention. The location for the attachment points  231 ,  233  would likewise adjust depending on the location of the zipper sliders, e.g., if the zipper sliders for the zippers  201 ,  202  were located on the bottom of the trampoline  200 , then the attachment points  231 ,  233  would be located on the bottom of the trampoline  200 , according to an embodiment of the invention. 
     The zipper  201  and/or the zipper  202  could comprise one or more zipper segments that attach the flexible mat  206  and the edge pad  203  to the safety layer  205 , according to an embodiment of the invention. For example, the edge pad  203  could be connected to the safety layer  205  by three zippers (collectively comprising zipper  202 ), for example, aligned in series along the common edge between the safety layer  205  and the edge pad  203 , according to an embodiment of the invention. Such an arrangement might involve lower cost and be simpler to assemble. 
     The thickness of the flexible mat  206  is typically in the range of 0.2 mm to 1 mm. However, the flexible mat  206  is usually reinforced at its edge, resulting in a higher thickness at the edge of the flexible mat  206 . The safety layer  205  is sized accordingly for an appropriate fit with the flexible mat  206 . 
     The safety layer  205  may expand and contract as the user jumps up and down on the trampoline  200 , avoiding a build-up of excess tension in the edge pad  203  or the flexible mat  206  that could possible cause harm to either the zipper  202  or the zipper  201 . 
     As previously discussed, the flexible mat  206  is retained in tension by a plurality of resilient members  209  (e.g., a coiled spring), according to an embodiment of the invention. The resilient members  209  are attached at or adjacent to an edge  217  of the flexible mat  206  by attachments  219  that include D-shaped or triangle-shaped rings  221 . The attachment  219  permits the at least one resilient member  209  to connect to the flexible mat  206 . It is possible to arrange the attachments  219  for the at least one resilient member  209  at the upper side of the flexible mat  206  in the vicinity of the edge  217  or at the underside of the flexible mat  206  in the vicinity of the edge  217  of the flexible mat  206 . The attachments  219  shown in  FIGS. 2A and 2B  attach on the underside of the flexible mat  206 , according to an embodiment of the invention. 
     The edge  217  of the flexible mat  206  also provides a common edge for the zipper  201  to attach to the safety layer  205 , according to an embodiment of the invention. The edge pad  203  has a similarly corresponding edge that provides a common edge for the zipper  202  to attach the edge pad  203  to the safety layer  205 , according to an embodiment of the invention. 
       FIG. 3  illustrates the safety layer  205  in a trampoline  200  from a cross section point of view and in the context of additional parts of the trampoline  200 , according to an embodiment of the invention. As shown in  FIG. 3 , the safety layer  205  attaches to the flexible mat  206  via zipper  201 , and the safety layer  205  attaches to the edge pad  203  via the zipper  202 , according to an embodiment of the invention. 
     As previously discussed, the safety layer  205  may expand and contract as the user jumps up and down on the trampoline  200 , avoiding a build-up of excess tension in the edge pad  203  or the flexible mat  206  that could possible cause harm to either the zipper  202  or the zipper  201 . The zipper  201  and/or the zipper  202  may comprise one or more zipper segments that attach the flexible mat  206  and the edge pad  203  to the safety layer  205 , according to an embodiment of the invention. For example, the edge pad  203  could be connected to the safety layer  205  by three zippers (collectively comprising zipper  202 ), for example, aligned in series along the common edge between the safety layer  205  and the edge pad  203 , according to an embodiment of the invention. Such an arrangement might involve lower cost and be simpler to assemble. 
     As shown in  FIG. 3 , the edge pad  203  comprises a covering  204  that has been crimped or folded to facilitate the insertion of a cushioning material  213  into the edge pad  203 , according to an embodiment of the invention. The cover  204  may comprise a durable plastic material while the cushioning material  213  may comprise a material such as foam rubber. 
     The edge pad  203  covers a frame  211  and the trampoline suspension system comprised of at least one resilient member  209  (e.g. a coiled spring). The resilient member  209  (e.g., the spring) shown in  FIG. 3 , one member of the set of resilient members of the trampoline suspension system, attaches at one end to the frame  211  and at the other end to a D-ring  221  that itself attaches to the flexible mat  206  via attachment  219  in the arrangement discussed above in conjunction with  FIGS. 2A and 2B . This arrangement of the suspension system is known in the prior art, such as shown in PCT/EP2017/057961, “Safety Net for a Trampoline, A Trampoline, and a Method of Arranging a Safety Net in a Trampoline,” which is hereby incorporated by reference. 
       FIG. 4  illustrates a safety layer  405  in a trampoline  400 , according to an alternative embodiment of the invention. As shown in  FIG. 4 , the safety layer  405  attaches to the flexible mat  406  via zipper  401 , and the safety layer  405  is physically attached to the edge pad  403  along line  415  via a permanent attachment device  417 . The zipper  401  typically surrounds the flexible mat  406 , according to an embodiment of the invention. The permanent attachment device  417  could comprise sewing, stitching, gluing, stapling, snapping, buttoning or some other attachment means that would securely attaching the edge pad  403  to the safety layer  405  along the line  415 . The permanent attachment device  417  is shown in  FIG. 4  as stitching that connects the safety layer  405  to the edge pad  403 . 
     The safety layer  405  may expand and contract as the user jumps up and down on the trampoline  400 , avoiding a build-up of excess tension in the edge pad  403  or the flexible mat  406  that could possible cause harm to either the zipper  401  or the permanent attachment device  417 . The zipper  401  could comprise one or more zipper segments that attach the flexible mat  406  and the safety layer  405 , according to an embodiment of the invention. For example,  FIG. 4  shows the flexible mat  406  connected to the safety layer  405  by two zippers  401   a .  401   b  (collectively comprising zipper  401 ), for example, aligned in series along the common edge between the safety layer  405  and the flexible mat  406 , according to an embodiment of the invention. Such an arrangement might involve lower cost and be simpler to assemble. 
     As shown in  FIG. 4 , the edge pad  403  comprises a covering  404  that has been crimped or folded to facilitate the insertion of a cushioning material  413  into the edge pad  403 , according to an embodiment of the invention. The cover  404  may comprise a durable plastic material while the cushioning material  413  may comprise a material such as foam rubber. 
     The edge pad  403  covers a frame  411  and the trampoline suspension system (e.g., the resilient member  409 ). The resilient member  409  (e.g., a coiled spring), one member of the set of resilient members of the trampoline suspension system, attaches at one end to the frame  411  and at the other end to a D-ring  419  that itself attaches to the flexible mat  406  in a manner similar to that disclosed in conjunction with  FIG. 3 . 
       FIG. 5  illustrates a safety layer  505  in a trampoline  500 , according to an alternative embodiment of the invention. As shown in  FIG. 5 , the safety layer  505  attaches to the edge pad  503  via zipper  502 , and the safety layer  505  is physically attached to the flexible mat  506  along line  509  via a permanent attachment device  517 . The zipper  502  typically surrounds the edge pad  503 , according to an embodiment of the invention. The permanent attachment device  517  could comprise sewing, stitching, gluing, stapling, snapping, buttoning or some other attachment means that would securely attach the flexible mat  506  to the safety layer  505 . The permanent attachment device  517  is shown in  FIG. 5  as stitching that connects the safety layer  505  to the flexible mat  506 . 
     The safety layer  505  may expand and contract as the user jumps up and down on the trampoline  500 , avoiding a build-up of excess tension in the edge pad  503  or the flexible mat  506  that could possible cause harm to either the zipper  502  or the permanent attachment device  517 . The zipper  502  could comprise one or more zipper segments that attach the edge pad  503  to the safety layer  505 , according to an embodiment of the invention. For example,  FIG. 5  shows the edge pad  503  connected to the safety layer  505  by two zippers  502   a ,  502   b  (collectively comprising zipper  502 ), for example, aligned in series along the common edge between the safety layer  505  and the edge pad  503 , according to an embodiment of the invention. Such an arrangement might involve lower cost and be simpler to assemble. 
     As shown in  FIG. 5 , the edge pad  503  comprises a covering  504  that has been crimped or folded to facilitate the insertion of a cushioning material  513  into the edge pad  503 , according to an embodiment of the invention. The cover  504  may comprise a durable plastic material while the cushioning material  513  may comprise a material such as foam rubber. 
     The edge pad  503  covers a frame  511  and the trampoline suspension system comprising a resilient member  509 . The resilient member  509  (e.g., a coiled spring), one member of the set of resilient members of the trampoline suspension system, attaches at one end to the frame  511  and at the other end to a D-ring  519  that itself attaches to the flexible mat  506  in a manner similar to that disclosed in conjunction with  FIG. 3 . 
       FIG. 6  illustrates a safety layer  605  in a trampoline  600 , according to an alternative embodiment of the invention. As shown in  FIG. 6 , the safety layer  605  is divided into a first portion  621  and a second portion  622 . The first portion  621  is attached to the second portion  622  via a zipper  625 . 
     An edge of the first portion  621  is physically attached to a flexible mat  606  along line  631  via a permanent attachment device  637 . The permanent attachment device  637  could involve sewing, stitching, gluing, stapling, or some other means that would securely attach the flexible mat  606  to the first portion  621 , according to an embodiment of the invention. 
     An edge of the second portion  622  is physically attached to an edge pad  603  along line  632  via a permanent attachment device  638 , according to an embodiment of the invention. The permanent attachment device  638  could involve sewing, stitching, gluing, stapling, or some other means that would securely attach the edge pad  603  to the second portion  622 . 
     The safety layer  605  may expand and contract as the user jumps up and down on the trampoline  600 , avoiding a build-up of excess tension in the edge pad  603  or the flexible mat  606  that could possible cause harm to either the permanent attachment device  637  or the permanent attachment device  638 . 
     The zipper  625  could comprise one or more zipper segments that attach the first portion  621  of the safety layer  605  to the second portion  622  of the safety layer  605 , according to an embodiment of the invention. For example, the first portion  621  could be connected to the second portion  621  by three zippers (collectively comprising zipper  625 ), according to an embodiment of the invention. Such an arrangement might involve lower cost and be simpler to assemble. 
     As shown in  FIG. 6 , the edge pad  603  comprises a covering  604  that has been crimped or folded to facilitate the insertion of a cushioning material  613  into the edge pad  603 , according to an embodiment of the invention. The cover  604  may comprise a durable plastic material while the cushioning material  613  may comprise a material such as foam rubber. 
     The edge pad  603  covers a frame  611  and the trampoline suspension system comprising resilient member  609 . The resilient member  609  (e.g., the coiled spring), one member of the set of resilient members of the trampoline suspension system, attaches at one end to the frame  611  and at the other end to a D-ring  619  that itself attaches to the flexible mat  606  in a manner similar to that disclosed in conjunction with  FIG. 3 . 
       FIG. 7  illustrates a trampoline  700 , according an embodiment of the invention. As shown in  FIG. 7 , a safety layer  705  attaches to the flexible mat  706  via zipper  701 , and the safety layer  705  attaches to the edge pad  703  via the zipper  702 , according to an embodiment of the invention. The trampoline  700  resembles the trampoline  300  shown in  FIG. 3  but provides additional detail for the overall trampoline  700 . The zipper  701  typically surrounds the flexible mat  706 , and the zipper  702  typically surrounds the edge pad  703 , according to an embodiment of the invention. 
     The safety layer  705  may expand and contract as the user jumps up and down on the trampoline  700 , avoiding a build-up of excess tension in the edge pad  703  or the flexible mat  706  that could possible cause harm to either the zipper  702  or the zipper  701 . The zipper  701  and/or the zipper  702  could comprise one or more zipper segments that attach the flexible mat  706  and the edge pad  703  to the safety layer  705 , according to an embodiment of the invention. For example, the edge pad  703  could be connected to the safety layer  705  by three zippers (collectively comprising zipper  702 ), for example, aligned in series along the common edge between the safety layer  705  and the edge pad  703 , according to an embodiment of the invention. Such an arrangement might involve lower cost and be simpler to assemble. 
     As shown in  FIG. 7 , the edge pad  703  comprises a covering  704  that has been crimped or folded to facilitate the insertion of a cushioning material  713  into the edge pad  703 , according to an embodiment of the invention. The cover  704  may comprise a durable plastic material while the cushioning material  713  may comprise a material such as foam rubber. 
     The edge pad  703  covers a frame  711  and the trampoline suspension system comprising a resilient member  709 . The frame  711  is held off the ground by legs  715 , according to an embodiment of the invention. The resilient member  709  (e.g., a coiled spring), one member of the set of resilient members of the trampoline suspension system, attaches at one end to the frame  711  and at the other end to a D-ring  719  that itself attaches to the flexible mat  706 . The edge of the spring  709  is bent downward  721  and way from the flexible mat  706 , according to an embodiment of the invention. This arrangement provides additional user safety since the point of the spring  709  has been bent away from the upper surface of the flexible mat  706 . The arrangement of the suspension system is otherwise as shown in  FIG. 3 . 
       FIG. 8  illustrates a perspective view of a trampoline  800 , according to an embodiment of the invention. The trampoline  800  comprises a flexible mat  806 , edge pad  803 , and a safety layer  805 . In the embodiment shown in  FIG. 8 , the safety layer  805  is attached to the flexible mat  806  by a zipper  801  (comprised of zipper segments  801   a - 801   d , as discussed below) and attached to the edge pad  803  via a permanent attachment device such as the permanent attachment device  417  disclosed in  FIG. 4 . The zipper  801  typically surrounds the flexible mat  806 , according to an embodiment of the invention. 
     The safety layer  805  shown in  FIG. 8  is folded under the edge pad  803  as the safety layer  805  would appear in a resting position, such as when the user is not bouncing on the trampoline  800  and the flexible mat  806  is not depressed by the user jumping on the flexible mat  806 . When the user is bouncing on the flexible mat  806 , then the safety layer  805  extends in a manner similar to the depiction of the safety layer  205  shown in  FIG. 3 , the safety layer  405  shown in  FIG. 4 , the safety layer  505  shown in  FIG. 5 , the safety layer  605  shown in  FIG. 6 , and the safety layer  705  shown in  FIG. 7 . If the user bounces high enough on the trampoline  800 , then the folds in the safety layer  805  straighten out and the material of the safety layer  805  may even stretch, according to an embodiment of the invention. 
     The zipper  801  comprises a plurality of zipper segments  801   a - 801   d  that attach the flexible mat  806  to the safety layer  805 , according to an embodiment of the invention. For example, the flexible mat  806  could be connected to the safety layer  805  by four zippers  801   a - 801   d  (that collectively comprise the zipper  801 ), aligned in series along the common edge between the safety layer  805  and the flexible mat  806 , according to an embodiment of the invention. Such an arrangement might involve lower cost and be simpler to assemble. The number of zipper segments used would depend upon factors such as zipper cost and efficiency goals related to the ease of assembly. The zippers  801   a - 801   d  typically surround the mat  806 , according to an embodiment of the invention. 
     The safety layer  805  could alternatively be attached to the flexible mat  806  by a permanent attachment device, such as the permanent attachment device  517  disclosed in  FIG. 5 . The safety layer  805  could also alternatively be attached to the edge pad  803  via a zipper, such as the zipper  502  shown in  FIG. 5 . Thus, the safety layer  805  in trampoline  800  could employ one zipper (or a combination of zipper segments) or two zippers (or a combination of zipper segments) in a manner disclosed in  FIGS. 3-6 , according to various embodiments of the invention. 
     The safety layer  805  may expand and contract as the user jumps up and down on the trampoline  800 , avoiding a build-up of excess tension in the edge pad  803  or the flexible mat  806  that could possible cause harm to either the permanent attachment device  817  or the zipper  801 . 
     The flexible mat  806  is encompassed by the frame  811 . The frame  811  comprises legs  815 , such that the trampoline  800  stands on the ground  819  via the legs  815 . The edge pad  803  covers the resilient members  809  (e.g., a coiled spring) and the frame  811 .  FIG. 8  shows the resilient member  809  in a cutaway of the edge pad  803 . The resilient members  809  surround the flexible mat  806  and attach to the frame  811 . The edge pad  803  would normally provide a complete covering without the cutaway portion shown in  FIG. 8 . In the illustrated embodiment, the flexible mat  806  and the surrounding frame  811  are shown as circular, but they may also be e.g. oval, square, or rectangular. 
     The trampoline  800  includes a safety net  817  attached to a number of safety poles  820 . The safety net  817  attaches to the outside edge of the edge pad  803 , according to an embodiment of the invention. The safety net  817  and safety poles  820  may be configured in a manner such as disclosed in the applicants&#39; PCT/EP2017/057961 and/or as disclosed in applicants&#39; pending EP18154158.2 application. Both applications are incorporated herein by reference. 
     The safety net  817  prevents a user from falling off the flexible mat  806  and hitting the ground  819 . The safety net  817  may be retained by a safety net retainer, e.g. a number of support poles  820  extending upwardly from the frame  811  for carrying the safety net  817  surrounding the flexible mat  806 , according to an embodiment of the invention. 
       FIG. 9  illustrates a trampoline  900 , according to an embodiment of the invention. The trampoline  900  comprises a flexible mat  906 , edge pad  903 , and a safety layer  905 . In the embodiment shown in  FIG. 9 , the safety layer  905  is attached to the flexible mat  906  by a zipper  901  (comprised of zipper segments  901   a - 901   d , as described below) and attached to the edge pad  903  via a permanent attachment device such as the permanent attachment device  417  disclosed in  FIG. 4 . The zipper  901  typically surrounds the flexible mat  906 , according to an embodiment of the invention. 
     The safety layer  905  shown in  FIG. 9  is folded under the edge pad  903  as the safety layer  905  would appear in a resting position, such as when the user is not bouncing on the trampoline  900  and the flexible mat  906  is not depressed by the user jumping on the flexible mat  906 . When the user is bouncing on the flexible mat  906 , then the safety layer  905  extends in a manner similar to the depiction of the safety layer  205  shown in  FIG. 3 , the safety layer  405  shown in  FIG. 4 , the safety layer  505  shown in  FIG. 5 , the safety layer  605  shown in  FIG. 6 , and the safety layer  705  shown in  FIG. 7 . If the user bounces high enough on the trampoline  900 , then the folds in the safety layer  905  straighten out and the material of the safety layer  905  may even stretch, according to an embodiment of the invention. 
     The zipper  901  comprises a plurality of zipper segments  901   a - 901   d  that attach the flexible mat  906  to the safety layer  905 , according to an embodiment of the invention. For example, the flexible mat  906  could be connected to the safety layer  905  by four zippers  901   a - 901   d  (that collectively comprise the zipper  901 ), aligned in series along the common edge between the safety layer  905  and the flexible mat  906 , according to an embodiment of the invention. Such an arrangement might involve lower cost and be simpler to assemble. The number of zipper segments used would depend upon factors such as zipper cost and efficiency goals related to the ease of assembly. The zippers  901   a - 901   d  typically surround the mat  906 , according to an embodiment of the invention. 
     The safety layer  905  could alternatively be attached to the flexible mat  906  by a permanent attachment device, such as the permanent attachment device  517  disclosed in  FIG. 5 . The safety layer  905  could alternatively be attached to the edge pad  903  via a zipper, such as the zipper  502  shown in  FIG. 5 . Thus, the safety layer  905  in trampoline  900  could employ one zipper (or a combination of zipper segments) or two zippers (or a combination of zipper segments) in a manner disclosed in  FIGS. 3-6 , according to an embodiment of the invention. 
     The flexible mat  906  is encompassed by the frame  911 . The frame  911  comprises legs  915 , such that the trampoline  900  stands on the ground via the legs  915 . The edge pad  903  covers the resilient members  909  (e.g., a coiled spring) and the frame  911 .  FIG. 9  shows the resilient member  909  in a cutaway of the edge pad  903 . The resilient members  909  surround the flexible mat  906  and attach to the frame  911 . The edge pad  903  would normally provide a complete covering without the cutaway portion shown in  FIG. 9 . In the illustrated embodiment, the flexible mat  906  and the surrounding frame  911  are shown as circular, but they may also be e.g. oval, square, or rectangular. 
     The safety layer  905  may expand and contract as the user jumps up and down on the trampoline  900 , avoiding a build-up of excess tension in the edge pad  903  or the flexible mat  906  that could possible cause harm to the zipper  901 . 
     The trampoline includes a safety net  921  attached to a number of safety poles  924 . The safety net  921  attaches to the inside edge of the edge pad  903 , according to an embodiment of the invention. The safety net  921  and safety poles  924  may be configured in a manner such as disclosed in the applicants&#39; PCT/EP2017/057961 and/or as disclosed in applicants&#39; pending EP18154158.2 application. Both applications are incorporated herein by reference. 
     The safety net  921  may be attached to the flexible mat  906 . Such an attachment helps to prevent the user from stepping on or between the resilient members  909 . However, even when using the safety net  921  attached to the flexible mat  906  in a conventional manner, there is still a risk that a foot or an arm of the user (e.g. if landing unfortunately in the vicinity of the edge pad  903  or the flexible mat  906 ) could slip out between the flexible mat  906  and the safety net  921 , e.g. in the interspace between two attachments of the resilient member to the flexible mat. If this would occur, there is a risk of discomfort and even injury to the user of the trampoline  900 . 
     In order to reduce this risk, one could sew the safety net  921  to the flexible mat  906  in the vicinity of the edge of the flexible mat  906 . However, sewing is costly and cumbersome, especially since the pieces would typically be sewn after the trampoline has been mounted in order for the sewing to be made over the attached resilient members. 
     Embodiments of the invention may comprise a kit that is provided to the user in the form of a series of parts, such as a flexible mat, an edge pad, a frame (possibly in a number of pieces), a plurality of resilient members, and a safety layer. Instructions for assembling a trampoline comprising these parts can be provided to the user. Having at least one zippered attachment on the safety layer should shorten the user&#39;s assembly time, especially in comparison with an alternative such as sewing or stitching one side of the safety layer to either the edge pad or the flexible mat. In embodiments where the safety layer does not comprise two zippers, the non-zippered side of the safety layer would typically be attached to either the edge pad or the flexible mat in the factory. 
     The trampolines described herein, such as but not limited to the trampoline  800  shown in  FIG. 8  and the trampoline  900  shown in  FIG. 9  are amenable to assembly, particularly assembly outside of the factory where they were made such as by a user or a delivery person. The assembly can typically be accomplished by hand or with a minimum number of tools, according to an embodiment of the invention. The legs (e.g., the legs  815  shown in  FIG. 8 ) are typically attached to the frame (e.g., the frame  811 . The resilient members (e.g., the resilient members  809 ) may be next attached to the fame, e.g., the frame  811 . The edge pad, e.g., the edge pad  803  may be next placed on top of the frame  811  and the resilient members. The safety layer  805  may be next attached to the edge pad  803  and the flexible mat  806 , such as by attached a zipper. The safety poles  820  may be next attached to the frame, and the safety net  817  may be next attached. In some embodiments, the safety net  817  may need to be attached or placed between the flexible mat  806  and the resilient members  809  prior to the connection of the flexible may  806  and the resilient members  809 , according to an embodiment of the invention. 
     Further modifications of the invention within the scope of the appended claims are feasible. As such, the present invention should not be considered as limited by the embodiments and figures described herein. Rather, the full scope of the invention should be determined by the appended claims, with reference to the description and drawings. 
     Various embodiments of the invention have been described in detail with reference to the accompanying drawings. References made to particular examples and implementations are for illustrative purposes, and are not intended to limit the scope of the invention or the claims. 
     It should be apparent to those skilled in the art that many more modifications of the trampoline besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except by the scope of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. 
     Headings and sub-headings provided herein have been provided as an assistance to the reader and are not meant to limit the scope of the invention disclosed herein. Headings and sub-headings are not intended to be the sole or exclusive location for the discussion of a particular topic. 
     While specific embodiments of the invention have been illustrated and described, it will be clear that the invention is not limited to these embodiments only. Embodiments of the invention discussed herein may have generally implied the use of materials from certain named equipment manufacturers; however, the invention may be adapted for use with equipment from other sources and manufacturers. Equipment used in conjunction with the invention may be configured to operate according to conventional methods and protocols and/or may be configured to operate according to specialized protocols. Numerous modifications, changes, variations, substitutions and equivalents will be apparent to those skilled in the art without departing from the spirit and scope of the invention as described in the claims. In general, in the following claims, the terms used should not be construed to limit the invention to the specific embodiments disclosed in the specification, but should be construed to include all systems and methods that operate under the claims set forth hereinbelow. Thus, it is intended that the invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. 
     All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.