Rotationally molded climbing element with thermoplastic base body and functional contact surface

Abstract

Climbing element, in particular climbing hold, comprising a base body produced by rotational molding from a thermoplastic material.

Description

1. Technical field

[0001] The invention relates to climbing elements with a functional contact surface, in particular hand, foot, macro, and volume elements, which are used on artificial climbing and bouldering walls for sporting, training-related, or competition-oriented purposes. It further relates to a method for manufacturing such climbing elements by rotational molding of a thermoplastic material, as well as to suitable molding tools for carrying out this method.

[0002] In contrast to known rotationally molded wall modules that serve as load-bearing or decorative surface elements, the present invention relates to functional climbing elements whose geometry and surface structure are designed for direct contact with the hands or feet of climbers.

[0003] Furthermore, the invention relates to a method for manufacturing such climbing elements by rotational molding of thermoplastic materials and to suitable molding tools for carrying out this method.

[0004] For the purposes of the present invention, the term "climbing element" means any component that can be attached to a climbing wall and is used by climbers as a handhold or foothold, regardless of its geometric size or function.

[0005] The term "rotary forming" refers to a thermoplastic forming process in which a polymeric powder or granules are introduced into a heated mold that rotates around at least two axes, causing the material to melt and be evenly distributed on the inner wall of the mold and, after cooling, to form a hollow or shell-shaped body.

[0006] The invention relates in particular to climbing elements whose base body consists of a recyclable thermoplastic material and whose gripping surface is formed after the molding process by structural design or subsequent surface treatment. The gripping surface can be coated or designed as a separate, detachably connected component. Both variants represent possible embodiments of the invention. 2. State of the art

[0007] Climbing holds and elements are used on artificial climbing and bouldering walls for training and competition purposes. Various materials and manufacturing processes are known from current technology.

[0008] Conventional climbing holds are predominantly manufactured by casting thermosetting resin systems into molds. Unsaturated polyester resins (PE) or polyurethane resins (PU) are mainly used in this process.

[0009] Polyester resin handles have a hard, “stone-like” feel, good abrasion resistance and temperature resistance, but are brittle and can break under impact or bending stress, resulting in sharp-edged fracture surfaces.

[0010] Polyurethane handles are lighter and have a warmer, softer feel. They allow for greater freedom in shaping but exhibit limited UV and temperature resistance. Long-term use leads to surface wear and smoothing, which reduces the coefficient of friction. Furthermore, PU formulations tend to change color under UV exposure, especially with light or fluorescent pigments.

[0011] Glass fiber reinforced plastics (GFRP) are also known for large-volume wall segments and macro elements. These allow for complex geometries with reduced weight, but require high manufacturing effort and make material recycling more difficult because they consist of composite systems.

[0012] Climbing elements made of wood are also known, usually milled from plywood or solid wood and then coated. They are ecologically advantageous, but exhibit lower durability and surface quality than polymer-based systems.

[0013] Coating systems made of resins and quartz sand are typically used to create the friction surface. These create defined roughnesses and represent the state of the art; variants with combined areas of different friction ("dual texture") are also known.

[0014] The fastening technology includes centrally arranged bores with cast-in or inserted metal bushings as well as additional screw holes for anti-rotation protection.

[0015] Modular concepts are also described, in which individual climbing elements are connected to base elements in a rotatable or interchangeable manner. However, these concepts mostly concern the geometric combination or mounting systems and not the replacement of the grip surface itself.

[0016] Additive manufacturing processes, such as laser sintering or filament extrusion, have also been proposed for climbing holds. They allow for integrated surface structures, but are currently only suitable for mass production to a limited extent in terms of cost and process technology.

[0017] Rotational molding of thermoplastic materials is a well-known method for manufacturing large-volume hollow bodies, such as tanks or containers. In the field of climbing, it has so far only been described for wall panels, but not for the production of climbing holds or macro-elements with integrated or modular grip surfaces.

[0018] Furthermore, known coating systems, particularly those based on polyurethane resins, exhibit limited recyclability. Because these coatings are firmly bonded to thermosetting or fiber-reinforced substrates, material separation without mechanical damage is practically impossible. Consequently, the base material cannot be returned to a closed-loop material cycle.

[0019] Furthermore, existing systems do not offer a technical solution for renewing worn grip surfaces independently of the base body. Prior art modular approaches primarily involve geometric combinations or assembly systems, but not the targeted replacement of the functional surface.

[0020] Thus far, there is no process or component that combines a recyclable thermoplastic structure with a functional, optionally replaceable grip surface. 3. Description of the invention Technical problem

[0021] Based on the described state of the art, the object of the invention was to provide a climbing element that can be manufactured economically, recycled materially and superficially renewed if necessary, without having to replace the entire grip.

[0022] In particular, a process should be developed that ensures the recyclability of the base body, reduces material usage and production waste, while guaranteeing mechanical strength, safety and haptic quality at the level of conventional climbing holds.

[0023] Furthermore, the invention should offer a high degree of design freedom, uniform wall thicknesses and the possibility of direct integration of surface structures in the manufacturing process. Solution

[0024] This task is solved by a climbing element, comprising: • a base body produced by rotational molding from a thermoplastic material, • a gripping surface that is formed after the molding process by coating, structural shaping or a separate, detachably connected component.

[0025] The thermoplastic base body is manufactured from a powdered or microgranulated polymer material, such as polypropylene (PP), polyethylene (PE), thermoplastic polyurethane (TPU), or polylactic acid (PLA), using a rotational molding process. This process enables the dimensionally accurate production of large-volume, shell- or hollow-body-like components with uniform wall thickness and minimal tooling requirements.

[0026] The grip surface can be implemented in different designs: • as a structure directly molded during rotational molding, • as a subsequently applied coating, preferably resin-based with quartz sand filling, • or as a modular, detachably attached surface element (for example, grip tape, polymer or wood insert). Advantages of the invention

[0027] The inventive method enables the production of climbing elements made of thermoplastic materials, which are characterized by uniform wall thicknesses, high impact strength and reproducible component quality.

[0028] The rotational molding process completely transfers the material into the component, eliminating material waste and offcuts. The entire polymer is recycled, creating a closed-loop material cycle. After their service life, the components can be reused without remelting, as grinding and crushing into molding powder is sufficient for reprocessing.

[0029] Compared to other thermoplastic processes based on sheet forming, rotational forming allows for higher material utilization and lower process complexity, as the component is produced ready for use and in its final form in a single process step.

[0030] A further significant technical advantage lies in the fact that the textured surface can be created directly during the forming process. The texturing of the inner tool wall is transferred directly to the component surface, eliminating the need for additional coating or post-processing steps. Such direct structural representation is not achievable with known forming processes.

[0031] Furthermore, the process allows for greater geometric design freedom and reduces the required tooling and equipment costs, as the shaping takes place without pressure and at moderate temperatures.

[0032] The combination of closed-loop material recycling, easy recyclability, process simplification and integrated surface structuring leads to an overall technical result that was not achievable with known methods. 4. Examples of Implementation. General

[0033] In a preferred embodiment, the entire climbing hold or the base body of a multi-part climbing element is manufactured by rotational molding of a thermoplastic material.

[0034] The process enables the economical production of hollow, impact-resistant and dimensionally stable components with uniform wall thickness and low tooling costs.

[0035] Preferred materials are polypropylene (PP), polyethylene (PE), thermoplastic polyurethane (TPU), or polylactic acid (PLA), as well as their recyclates. These materials are particularly suitable for rotational molding because they exhibit good melt distribution, high impact strength, and recyclability.

[0036] The thermoplastic material used is completely incorporated into the component during rotational molding and can be recycled after use by mechanical shredding and subsequent grinding. The resulting powder can then be reused as raw material in the rotational molding process, thus creating a closed material cycle.

[0037] The rotary forming tool can be made in one or more parts and can rotate around one or more axes.

[0038] In preferred process variants, several geometrically similar or mirror-image climbing elements can be produced simultaneously in the same tool.

[0039] This reduces processing time and enables optimized material distribution. The tool's parting plane defines the wall connection surface of the climbing element, which can be planar or contoured. b. Coated version

[0040] In one embodiment, a friction coating is subsequently applied to the rotationally molded base body. The coating can correspond to a conventional system, in particular based on a polyurethane resin with embedded quartz sand or silicate particles. This maintains the proven surface feel and friction characteristics of classic climbing holds, while the base body remains thermoplastic and materially recyclable. Depending on its composition, the coating can be permanent or reversible. c. Modular design

[0041] In another embodiment, the climbing hold comprises a detachably attached surface element that forms the gripping surface. The surface element can be made of plastic or wood and can be coated or uncoated. It is attached via snap-fit, screw, or adhesive connections, and reversible adhesive systems can also be used.

[0042] In another variant of this design, the gripping surface can be formed by an adhesive friction tape ("grip tape") which consists of a flexible carrier material with a structured or coated surface and is connected to the base body via an adhesive or reversible adhesive layer.

[0043] The modular design allows the grip surface to be renewed or varied independently of the base body. This extends the service life, reduces material consumption, and enables the use of different surfaces with varying friction or feel on the same base body. The modular construction thus further contributes to the sustainability and functional versatility of the climbing elements according to the invention. d. Monomaterial design

[0044] In another embodiment, the entire climbing hold, including the gripping surface, consists of the rotationally molded thermoplastic. The surface structure is formed directly during the molding process by structuring the inner surface of the mold, for example, by milling, sandblasting, or chemical etching. This results in a one-piece, monomaterial component that is fully recyclable and requires no further coating. The texture transfer allows for targeted adjustment of the friction properties and a reproducible surface quality. e. Combination and variant information

[0045] The embodiments described in sections 4.2 to 4.4 can be combined or modified with each other, provided this is technically compatible, without departing from the core of the invention. 5. Brief description of the characters

[0046] Fig. Figure 1 shows various views of a climbing hold according to the invention, consisting of a top view, front view, side view and a section AA, which together illustrate the overall geometric shape and the internal structure. The area shown with dashed lines indicates the coated grip zone, which is arranged on the outer surface that comes into contact during use.

[0047] Fig. Figure 2 shows the climbing hold in a perspective view to illustrate the three-dimensional shape and the position of the coated grip zone on the outer surface.

[0048] Since the drawings do not contain any numerical reference symbols, the following list serves only to assign the areas mentioned in the description: 1 Coated grip zone (shown as a dashed line) 2 Base body of the climbing hold

Claims

[1] Climbing element, in particular climbing hold, comprising a base body produced by rotational molding from a thermoplastic material. [2] Climbing element according to claim 1, characterized by that the base body is provided on its surface with a polymer-based coating, preferably based on a polyurethane resin with embedded quartz sand or silicate particles. [3] Climbing element according to claim 1, characterized by that the base body has a detachably attached gripping surface, which is designed as a separate surface element. [4] Climbing element according to claim 3, characterized by that the surface element includes an adhesive friction tape (“grip tape”) consisting of a flexible carrier material with a structured or coated surface. [5] Climbing element according to claim 1, characterized by, that the gripping surface is an integral part of the rotationally molded base body and its structure is directly generated by the mold surface of the tool. [6] Climbing element according to any one of the preceding claims, characterized by that the thermoplastic material consists of polypropylene (PP), polyethylene (PE), thermoplastic polyurethane (TPU) or polylactide (PLA). [7] Climbing element according to any one of the preceding claims, characterized by that the thermoplastic material is materially recyclable and suitable for closed material cycles. [8] Climbing element according to one of the preceding claims, manufactured in a rotational forming tool with one or more cavities, wherein the parting plane of the tool forms the wall connection surface of the climbing element. [9] Climbing element according to any one of claims 2 to 8, characterized bythat the coated, modular or monomaterial design is implemented individually or in combination.

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