Abstract
The invention relates to a drop-stitch element in which at least one adhesive fold (9, 10) of variable depth is introduced into a flat drop-stitch component (8) such that the outer skin of the drop-stitch component can be folded on one side of the drop-stitch component or, according to the position of the fold, alternately on both sides of the drop-stitch component.
Claims
1. Drop-stitch element, characterised in that at least one fold (9, 10, 12a, 12b) of variable depth is adhesively bonded into a flat drop-stitch component (8), wherein the outer skin of the drop-stitch component is folded or folded inwards on one or alternately on both sides of the component (8).
2. Drop-stitch element according to patent claim 1, wherein the fold (9, 10, 12a, 12b) starts at the upper surface of the drop-stitch component (8) and then extends increasingly deeper, in curved progression, to a maximum depth (12e, 12f), in order to then terminate, once again in curved progression, at the upper surface.
3. Drop-stitch element according to patent claim 2, wherein a plurality of adjacent folds (9, 10, 12a, 12b) are adhesively bonded into one side of the drop-stitch material.
4. Drop-stitch element according to any one of the preceding patent claims, wherein wedge-shaped punched-out portions (15a) are provided, in addition to the folds (9, 10, 12a, 12b), in order to urge the drop-stitch body into a rounded shape.
5. Drop-stitch element according to any one of the preceding patent claims, wherein the fold (9, 10, 12a, 12b) is covered by a covering layer (33) and/or a punched-out portion (15a) is covered by a cover (15c).
6. Drop-stitch element according to any one of the preceding patent claims, wherein a double-hull is produced by alternate folding (26, 27).
7. Drop-stitch element according to any one of the preceding patent claims, wherein by means of a drop-stitch component (8), having at least one fold (12b), and a second drop-stitch component (8), mirrored with respect to the first, an elongated hull shape is brought about in that the mirrored drop-stitch component (8) stretches around an inflatable or solid element (25).
8. Drop-stitch element according to patent claim 7, wherein a rigid bow and stern element (19) is fitted to the end face (16a, 16b) of the two drop-stitch bodies (8) at the bow and the stern, which bow and stern element is braced in a waterproof envelope (17) after inflation and forms a preferably pointed bow (13) and/or a preferably pointed stern.
9. Drop-stitch element according to patent claim 8, wherein the rigid bow and stern element (19) in the waterproof envelope (17) is attached, preferably spring-mounted, to the end face (16a, 16b) of the drop-stitch body at the bow and stern.
10. Method for joining a drop-stitch element according to any one of the preceding claims, characterised by an adhesive technique, wherein one side of at least one drop-stitch component (8) is folded and adhesively bonded in the region of the fold (9, 10, 12a, 12b).
11. Method according to claim 10, characterised in that two mirror-identical drop-stitch components (8) are combined to form a drop-stitch element.
Description
[0043] FIG. 1 shows a cross-sectional view of a kayak made from a drop-stitch material, manufactured according to the current state of the art, consisting of a left side wall 1, a right side wall 2 and a bottom 3. The side walls and bottom are in each case adhesively bonded in an airtight manner to end strips 4a, 4b, 4c. All adhesive bonds are additionally taped using a sealing tape 5 for better air-tightness. The two side walls have to be maintained stable in their inclined position by means of a bottom layer 6 and inside adhesive bonding 7.
[0044] FIG. 2 shows a cross-section through a kayak, which is adhesively bonded using the method according to the invention. The left and right side walls, as well as the bottom, consist of only one drop-stitch component 8. A left fold 9 and a right fold 10, on the inner side of the drop-stitch element, folded inwardly and adhesively bonded, bends the side wall toward the bottom. In the case of this adhesive technique, only one circumferential end strip 4d is necessary. This makes it possible to reduce to a minimum any air leakage, as well as the adhesive bonding work required for the kayak. In contrast to the state of the art, which requires a large number of adhesive bonds, the error potential during processing of the end strip 4d is significantly reduced. Also, turn-around times for producing a drop-stitch element, shown here, are substantially reduced as a result of the elimination of a bottom layer 6 and inside adhesive bonding 7, so that, in addition to the simplification of production, clear cost-savings over prior art are ensured.
[0045] FIG. 3 shows a perspective view of a rowing boat, in which, next to an upper edge 11, on the inner side, an upper circumferential fold 12a and a lower circumferential fold 12b are glued in, as a result of which the inner side of the drop-stitch element is shortened, while the outer side remains unshortened. As a result, the drop-stitch element assumes a rounded shape in sections. Folds 12a, 12b terminate in the first quarter of the rowing boat, so that, from there, the two sides of the drop-stitch element remain straight, i.e. non-rounded, thereby forming a straight pointed bow shape 13. A deeper fold 12b results in a more pronounced rounding in a transition region from the bottom to the side walls than is brought about by the upper fold 12a in a central region of the side walls. This design is illustrated in FIG. 5 in what follows.
[0046] The tapered bow shape according to FIG. 3 is also visible in FIG. 4. Here, a perspective view of the upper fold surface 12a and the lower fold surface 12b is shown. While the lower fold 12b extends to a maximum depth of the drop-stitch wall, thereby causing a considerable kink, the upper fold 12a is narrower resulting in a slight kink. Both folds follow a calculated curve which is responsible for the belly shape of the rowing boat. They begin at the upper surface of the inner wall 12c, 12d and extend to the maximum depth 12e, 12f of the drop-stitch element, in order to then return again to the surface of the inner wall in a curved progression. This results in the shape of the rowing boat, which is shown in a perspective view in FIG. 3.
[0047] FIG. 5 shows a sectional view through the rowing boat according to one of FIG. 3 or 4 with its two folds 12a and 12b. The upper fold 12a, having a negligible depth, results in a slight kink. The lower fold 12b is designed deeper than the fold 12a, so that a more pronounced rounding of the drop-stitch material is brought about, which confers its typical shape to the rowing boat. Beyond the roundings shown in FIGS. 3 and 4 and the varying depths of folds 12a and 12b, FIG. 5 already indicates that the rowing boat may also be manufactured from 2 mirror-symmetrical drop-stitch components. This is illustrated by the centrally-positioned bar, which indicates an adhesive point. A two-part embodiment of the drop-stitch element is shown in the following Figures. Reference numeral 33 denotes a covering layer, which covers the folds 12a, 12b. Such a covering layer 33 may be used in all embodiments for covering the respective folds.
[0048] FIG. 6 shows the rowing boat in plan view with a left half 14 and a right half 15 and the folds 12a, 12b. Both halves 14 and 15 and, consequently, also the folds 12a and 12b are designed in mirror-symmetrical fashion in relation to one another. Punching-out 15a is performed for both halves 14 and 15, material removal being carried out in each case, so that an approximately wedge-shaped punched-out portion, shown in FIG. 7 and extending from the outside to the inside, is removed from the drop-stitch material. Prior to adhesive bonding of the folds 12a, 12b, the punched-out portion 15a is joined to the punched-out portion 15b and sealed by an air-tight cover 15c.
[0049] FIG. 7 shows the blank, i.e. the non-adhesively bonded and unfolded drop-stitch material with the left half 14 of the rowing boat, the right mirror-symmetrical half 15 and the folding surfaces of the folds 12a, 12b. The punched-out portions 15a are shown in a possible initial shape, which is designed to taper from the upper edge 11 towards the bottom of the rowing boat. The punched-out portion 15a is in each case arranged in the rear region, viewed in the direction of travel of the rowing boat, so that by joining the punched-out portion to the joined punched-out portion 15b the final shape of the rowing boat with the relatively wide stern and a narrowing bow can be attained, as shown in FIGS. 3, 4 and 5.
[0050] FIG. 8 shows the bow with the adhesive bonding according to the method according to the invention, wherein the right side wall comes to rest next to the left side wall, the latter being adhesively bonded to one another. The left end face 16a of the left side wall and the right end face 16b of the right side wall form a bow nose having twice the width of the drop-stitch side wall. In addition to twice the width of a drop-stitch side wall, a joining location is provided between the two side walls and therefore also between the two end faces 16a and 16b, at which joining location the left half 14 and the right half 15 of the rowing boat converge.
[0051] FIG. 9 shows a waterproof envelope 17 as a pointed bow. In order to convert the wide bow nose, brought about by the two end faces of the drop-stitch side walls, into a narrow, pointed bow, a waterproof envelope 17 is provided, which is adhesively bonded to the drop-stitch walls by its rear end 18. The envelope 17 is placed over the end faces 16a and 16b and some way further, in an overlapping manner, over the two side walls of the rowing boat and is joined to them by way of adhesive bonding between the inner side of the envelope 17 and the outer side of the respective side wall.
[0052] FIG. 10 shows a rigid bow and stern element 19. The rigid bow and stern element 19 is inserted with its two ends into a fastening tube 20 and is pressed continuously forward against the envelope 17 by a spring element, which is located in the fastening tube 20, so that the said envelope 17 stretches. If a solid object is impacted by the watercraft, the rigid bow and stern element 19 is pushed back into the fastening tubes 20, so that the tube length A is shortened to tube length B. In the process, the envelope 17 is shortened and deformed as well. After the impact, the spring element pushes the rigid bow and stern element 19 forward again, so that the envelope 17 is automatically tensioned again and springs back into the tapering configuration (see FIG. 9), which is required for good hydrodynamics.
[0053] FIG. 11 shows a perspective side elevation and a plan view of a rigid bow and stern element 19, which is fastened by two tabs 21 to the end faces of the drop-stitch side walls. The rigid bow and stern element 19 is held by and/or guided through the tabs 21 which are each fastened on one side to one of the end faces 16a and 16b using, for example, a strut between the end faces 16a and 16b of the side walls. After inflation of the side walls, the rigid bow and stern element 19 is braced between the end faces of the side walls and the waterproof envelope 17, so that a fixed structural unit with a pointed bow is brought about. The pointed bow is formed by the envelope 17. The pointed envelope 17, stretched over the rigid bow and stern element 19, extends as an extension of the side walls at the level of the upper edge 11. In a non-inflated state of the drop-stitch element, not shown, the rigid bow and stern element 19 is movably maintained in the tabs, so that it can be folded in the direction of one of the side walls for simplified transport without it having to be completely disassembled. When next used, the rigid bow and stern element is once again urged back into its forward-facing end position, which is bounded by the envelope 17.
[0054] The illustrations in FIG. 12 show a particularly long, narrow watercraft in elevation, lateral view and plan view, the side wall 22 of which terminates in the adhesively bonded waterproof envelopes 17 on both sides, that is to say, both on the bow side as well as the stern side, as well as on the starboard and port side. A removable seat 23 is located in the centre and the bow-side section of the boat is stabilized by an inflatable middle segment 24, around which the side walls 22 bend slightly. The stern-side section of the boat is stabilised by two inflatable middle segments 24, which are glued in side-by-side, around which the side walls 22 likewise bend slightly. A further plan view shows an alternative embodiment of the stabilising middle segments. Instead of the inflatable middle segments 24, annular solid elements 25, for example being made of glass fibre or carbon, are incorporated, which provide the necessary stability between the two side walls and at the same time a slightly curved shape of the side walls. Owing to the different dimensioning of the solid elements 25, which are designed with a decreasing diameter from the centre of the watercraft towards the bow and the stern, the desired shape of the watercraft is attained while increasing stability.
[0055] A lower fold 12b begins in the front third of the surface of the inner side 12c of the side wall 22 and widens in a rounded progression in the centre of the boat up to a maximum depth 12e. The effects of the depth of the fold have already been described in detail when describing FIGS. 3 to 5.
[0056] FIG. 13 shows a two-part double-hull boat in elevation and plan view with a bottom-side fold 26 and a top-side fold 27. The varying depth of both folds along the longitudinal axis of the boat permits the round outline 28 of the floats. The bridge 29 forms part of the inner side wall 30 of the float. In the joined state of the fold, the top-side fold 27 forms the narrow underside of the respective float of the double-hull boat. By joining the top-side fold 27, the upper surfaces, also referred to as tops, of the drop-stitch material adjacent to the left and right of the top-side fold 27 (view according to FIG. 13 at the top) are urged into the shape shown at the top of FIG. 13, at an angle to each other. As a result of the varying depth of the top-side fold 27, the shape shown at the bottom in FIG. 13 is attained, which is narrower on the bow side than on the stern side. In addition to the top-side fold 27, a bottom-side fold 26 is required in order to form a bridge 29, which connects the two floats of the double-hull boat. For this purpose, a bottom-side fold 26, varying in its depth, is incorporated in the starting material on the underside, or, respectively, the bottom of the drop-stitch material. During subsequent joining of the bottom-side fold 26, the bridge 29 angles away from the outline 28 of the float in such a way that it runs approximately parallel to an underlying surface, not shown, on which the two floats are standing. In this way, a double-hull boat can be produced in a simple manner from two drop-stitch components. A design with only one drop-stitch component would also be conceivable.
[0057] FIG. 14 shows a long watercraft in an elevation, plan view and side elevation, on which one sits and paddles. It has on its upper side a central fold 31, which brings about a keel 32 on its underside. The keel 32 may vary in depth, due to the altered depth of the fold. A covering layer 33 conceals the underlying fold.
[0058] The invention relates to a drop-stitch element, in which at least one adhesively bonded fold of variable depth is introduced into a flat drop-stitch component such that the outer skin of the drop-stitch component can be folded on one side of the drop-stitch component or, according to the position of the fold, alternately on both sides of the drop-stitch component.
LIST OF REFERENCE NUMERALS
[0059] 1 Left side wall [0060] 2 Right side wall [0061] 3 Bottom [0062] 4a, 4b, 4c End strips [0063] 4d Circumferential end strip [0064] 5 Sealing tape [0065] 6 Bottom layer [0066] 7 Inside adhesive bonding [0067] 8 Drop-stitch part [0068] 9 Left fold [0069] 10 Right fold [0070] 11 Upper edge [0071] 12a Upper fold [0072] 12b Lower fold [0073] 12d, 12d Surface inner wall [0074] 12e, 12f Maximum depth [0075] 13 Bow, tapering [0076] 14 Left half [0077] 15 Right half [0078] 15a Punched-out portion [0079] 15b Joined punched-out portion [0080] 15c Air-tight cover [0081] 16a Left end face [0082] 16b Right end face [0083] 17 Waterproof envelope [0084] 18 Rear end [0085] 19 Rigid bow and stern element [0086] 20 Fastening tube [0087] 21 Tabs [0088] 22 Side wall [0089] 23 Seat, removable [0090] 24 Middle segments, inflatable [0091] 25 Solid element [0092] 26 Bottom-side fold [0093] 27 Top-side fold [0094] 28 Round outline [0095] 29 Bridge [0096] 30 Inner side wall [0097] 31 Centre-fold [0098] 32 Keel [0099] 33 Covering layer [0100] A Length [0101] B Length
