Vehicle frame

Abstract

The invention relates to the field of vehicle frames. In particular, the invention relates to a vehicle frame comprising rods and / or tubes, especially for muscle-powered vehicles. The vehicle frame for muscle-powered vehicles comprises a plurality of tube sections (1) and is characterized in that changes in direction between successive tube sections (1) are provided by bent intermediate sections (2), and several of the tube sections (1) together with intermediate sections (2) are present as a one-piece bent frame tube (3) made of bamboo tubing, so that conventional transitions can be replaced by means of the bent intermediate sections (2).

Description

Introduction The invention relates to the field of vehicle frames. In particular, the invention relates to a vehicle frame comprising rods and / or tubes, especially for muscle-powered vehicles. State of the art and disadvantages Vehicle frames, hereinafter referred to as vehicle frames or simply frames, serve to provide a supporting structure for other components such as wheels, drivetrain, seat, and the like. While so-called "monocoque" frames, in which a single load-bearing body absorbs the forces, as described, for example, in US Patent 4,230,332 A, are increasingly in use, frames traditionally, and still most widely used today, are those assembled from individual elements, particularly tubes and any associated connectors. For the purposes of this invention, "vehicles" refers to muscle-powered vehicles such as bicycles, cargo bikes, wheelchairs, walkers, bicycle trailers, and shopping carts. These vehicles all have in common that they have a frame comprising tubes or rods. These frames usually consist of many tube sections and various connectors (sleeves, etc.). The characteristics (weight, stiffness) of the frame are primarily determined by the chosen frame material. Metallic materials such as steel, aluminum, or titanium alloys are very robust, have a low tendency to break, and are easily repaired by welding or brazing. Frames made of plastic-based materials are usually reinforced with fiber materials such as carbon or glass fibers. These frames offer particularly high flexibility in terms of geometry and are often lighter, but have disadvantages due to their tendency to break very easily, as well as in terms of repairability and recycling. Frames made with tubes from renewable materials, especially bamboo, are also known, for example from the publications CN 1 07 284 586 A , ES 1 086 204 U , GB 1894 / 8 274 A , IT 2021 0001 2965 A1 , US 565 783 A , CN 1 16 262 538 A , KR 10 2014 0 143 944 A or WO 2012 / 065 256 A1 . In such frames, the individual tubes are usually connected to each other using specially shaped connecting pieces, so-called "sleeves". The use of couplings with pipes made from renewable raw materials presents the challenge of significant variation in the exact final shape of the pipe; publication GB 1895 / 8906A addresses this problem and proposes turning the pipe ends. Couplings specifically adapted to the properties of bamboo pipes are proposed, for example, in publication GB 1895 / 20837A. Turning the bamboo pipes damages them; this particularly affects the fibers, which are more prevalent on the outside of bamboo pipes, meaning they can no longer be used effectively to stabilize the frame. Another disadvantage of using lugs is their often considerable weight, resulting in a high overall frame weight. The use of lugs also prevents the utilization of the bamboo tube's fiber reinforcement at the joints and load-bearing points. Alternative joining methods include binding, even with natural material bands, gluing, perhaps in combination with wrapping using suitable mats, or the use of pins. However, the strength achievable with these methods is not always sufficient, especially for cargo bikes or trailers made from renewable resources. Here, too, the utilization of the bamboo tube's fiber reinforcement at the joints and load-bearing points is prevented, as a material of the same type is not used. Pins, nails, or screws, in particular, damage the fiber structure and lead to premature failure of the frame. Problem of the invention and solution The invention is therefore based on the objective of providing a vehicle frame made from renewable raw materials, particularly for muscle-powered vehicles, which avoids the aforementioned disadvantages. Accordingly, a vehicle frame according to the invention should have the lowest possible weight while offering stability comparable to conventional frames, and should avoid as many of the problems associated with the large variations in the exact final shape of the tube. The frame should utilize the advantages of the natural fiber reinforcement of bamboo without interrupting the fiber flow. The problem is solved by a vehicle frame according to claim 1. Advantageous embodiments can be found in the dependent subclaims, the following description, and the figures. Description The invention relates to a vehicle frame for muscle-powered vehicles of the type described above; it is irrelevant whether the vehicle is actively propelled (e.g., bicycle) or passively moved (e.g., trailer). It is equally irrelevant that an engine of any type may also be present for propelling the vehicle. The frame comprises a plurality of "tube sections." A tube section is a tube with a linear extension, and it is irrelevant whether the section has a physically definable beginning and end; accordingly, even a portion of a (longer) tube can be a tube section according to the invention. Typically, tube sections are straight (linear). However, they can also be curved. A simple example is the "diamond-shaped" frame of a bicycle; this typically has linear tube sections with a (also physical) beginning and end (top tube, head tube, seat tube, down tube, rear stays). At the transitions between the tube sections, these are typically connected to each other via lugs (or welds if the frame is made of metallic material). The vehicle frame according to the invention is characterized in that changes in direction between successive tube sections are provided by bent intermediate sections, and several of the tube sections together with intermediate sections are present as a one-piece bent frame tube made of bamboo tubing. This means, firstly, that a frame tube according to the invention comprises at least one linear or bent tube section, as well as an intermediate section bent according to the invention, so that (at least) a change in direction occurs along the longitudinal axis of the frame tube without interrupting the fiber direction of the tube.Due to the one-piece design according to the invention, this further means that this change of direction takes place without a conventional “transition” consisting, for example, of a sleeve, from a first, physically separate pipe section to a further, also physically separate, subsequent pipe section; both pipe sections are actually part of the same pipe. In other words, the invention replaces (or significantly reduces) the "transitions" known from the prior art, consisting of sockets or the like, by "intermediate sections" which are integrally formed with the adjacent pipe sections. Conventional transitions at the points of the intermediate sections, typically consisting of sleeves, connectors, or glued joints, can thus be advantageously replaced by the curved intermediate sections. Several tube sections with intermediate sections can therefore consist of a single bamboo tube without any connecting pieces. Ideally, a frame consists of a curved bamboo tube with only one connecting piece at the beginning and end points of the bamboo tube. The invention thus avoids the disadvantages known from the prior art. The vehicle frame according to the invention has a lower weight while offering comparable stability to conventional frames, since sleeves and other connection points can be largely dispensed with. Furthermore, the natural fiber reinforcement of the bamboo tube is utilized, and the fibers are not interrupted by bending. At the same time, the problems associated with the large variation in the exact final shape of bamboo tubes are largely avoided, since a vehicle frame according to the invention has a significantly reduced number of (potentially problematic) joints compared to conventional frames. Various embodiments of the invention are described in more detail below. In one embodiment, several of the tube sections are joined together with intermediate sections to form a ring, thus providing an endless frame tube. The joint between the (physical) beginning and end of the frame tube can be made by gluing, inserting, pinning, or other means. Such a frame tube is particularly lightweight and flexible and is suitable for a variety of frames for a wide range of vehicles, such as those listed below as examples. It should be noted that such vehicles can, of course, also be advantageously manufactured using frame tubes that are not continuous tubes. In one embodiment, the vehicle frame is a bicycle frame. Instead of the lugs typically found in bamboo frames, curved intermediate pieces are used, making the resulting frame lighter; moreover, the lugs and their associated connections to the (mostly linear) tube sections of known frames represent weak points that are eliminated in the solution according to the invention. In another embodiment, the vehicle frame is a cargo bike frame. Such frames can also be provided with sufficient stability using the vehicle frame according to the invention. In another embodiment, the vehicle frame is a trailer frame. This refers to bicycle trailers for both cargo and passengers, e.g., children. The "cabins" of the latter are particularly advantageous when provided by two parallel, continuous frame tubes connected to each other by cross braces. The basic element of an axle for attaching the trailer to a towing vehicle (bicycle) can also be made from a suitably bent frame tube. In another embodiment, the vehicle frame is a wheelchair frame. This frame can also advantageously consist of two identical, parallel frame tubes connected by cross braces. Hand grips can also be provided at the ends of the frame tubes. In another embodiment, the vehicle frame is a shopping cart frame. The above explanations apply analogously to this as well. A lower and an upper frame can be provided by continuous frame tubing; here too, cross braces are advantageously used. According to another embodiment, the vehicle frame is a rollator frame, for which the above explanations also apply. Finally, according to another embodiment, the vehicle frame can be a shopping trolley frame, in which cross braces are advantageously provided for stiffening, which are inserted into a main frame constructed from continuous tubing. Character description The invention is explained below by way of example with reference to the figures. Fig. 1 shows a trailer frame made of tube sections according to the invention; Fig. 2 shows a wheelchair comprising tube sections according to the invention; Fig. 3 shows a shopping cart comprising tube sections according to the invention; Fig. 4 shows the frame of a cargo bike comprising tube sections according to the invention; Fig. 5 shows a shopping trolley comprising tube sections according to the invention; Fig. 6 shows a rollator comprising tube sections according to the invention; Fig. 7 shows a stroller comprising tube sections according to the invention; Fig. 8 shows components of a bicycle frame comprising tube sections according to the invention. It should be noted that only some of the components are labelled with reference symbols in order to avoid impairing the clarity of the drawings. Fig. 1 shows a trailer frame 5 made of pipe sections 1 according to the invention. In this design, changes in direction between successive tube sections 1 are provided by curved intermediate sections 2. Several of the tube sections 1, together with their curved intermediate sections 2, are present as a single-piece, bent frame tube 3 made of bamboo. Here, the tube sections 1, together with the curved intermediate sections 2, are joined to form a ring, so that the frame tube 3 is provided in the form of an endless frame tube 4. The components 1, 2, and thus the frame tube 3 and 4, are made of bamboo without interrupting the natural grain of the bamboo. Conventional couplings (sleeves) are not used; instead, they are replaced by the curved intermediate sections 2. This results in the advantages described above. The two frame tubes 3 are connected to each other by cross braces 8. These are also made of the same material as the other frame tubes 3. As can be seen from the figure, the trailer frame 5 also includes a handle 6 and a drawbar 7, which also consists of or comprises sections of tubing with curved intermediate sections (reference numerals omitted). These components are also made of bamboo tubing. One of the two wheels (without reference numerals) is also shown, which can be attached to the lower crossbar 8 by suitable means. Fig. 2 shows a wheelchair with a wheelchair frame 9 comprising tube sections 1 according to the invention with curved intermediate sections 2. Here, too, several of the tube sections 1 with curved intermediate sections 2 are connected to form frame tubes 3. However, these are not entirely continuous frame tubes. The two frame tubes 3 are connected to each other by cross braces 8. They terminate in handles 6 at the top. Thus, components 1, 2, 3, and 6 are made from a single bamboo tube whose grain has not been interrupted. The wheels are also shown (without reference symbols). Fig. 3 shows a shopping cart whose frame 10 comprises tube sections 1 according to the invention with curved intermediate sections 2. The frame tubes 3 are designed as continuous frame tubes 4. Cross braces 8 are also present. The frame comprises an upper and a lower frame, which are connected to each other. Figure 4 shows the frame of a cargo bike. The cargo bike frame 11 is composed of several frame tubes 3, some of which run parallel to each other. It also includes a head tube at its front end, which is connected to the frame tubes 3 by suitable means (not shown). Fig. 5 shows a shopping trolley. The shopping trolley frame 13 comprises tube sections 1 according to the invention with curved intermediate sections 2 and cross braces 8. The frame tube 3 is designed as an endless frame tube 4. A handle 6 made of tube sections 1 with curved intermediate sections 2 is also provided. Likewise, further components (stand, basket support frame, each without reference numerals) are manufactured from tube sections 1 with curved intermediate sections 2. Fig. 6 shows a rollator with a rollator frame 14, constructed according to the invention. It comprises several frame tubes 3 and handles 6, but in the present design, no crossbars. A basket holder consisting of an endless frame tube 4 is located at the front (right in the image), which also increases the stability of the construction. Fig. 7 shows a stroller 15, the frame of which is also made of tubes 3 of the type according to the invention. Finally, Fig. 8 shows components of a bicycle comprising tube sections according to the invention. A bicycle frame 16 is shown in side and front views, as well as a fork 17. Only the mounting structures for the saddle and the bottom bracket are made of reinforced, possibly different, material; the remaining components can be made of bamboo, as shown. Accordingly, the frame shown comprises an endless frame tube 4 and a linear frame tube 3. The lugs shown (without reference numerals) enclose the respective tube from the outside. Reference symbol list 1 Tube section 2 Curved intermediate section 3 Frame tube 4 Endless frame tube 5 Trailer frame 6 Handle 7 Drawbar 8 Crossbars 9 Wheelchair frame 10 Shopping cart frame 11 Cargo bike frame 12 Head tube 13 Shopping trolley frame 14 Rollator frame 15 Stroller 16 Bicycle frame 17 Fork

Claims

Vehicle frame for muscle-powered vehicles, the frame comprising a plurality of tube sections (1), characterized in that changes of direction between successive tube sections (1) are provided by bent intermediate sections (2), and several of the tube sections (1) together with intermediate sections (2) are present as a one-piece bent frame tube (3) made from a bamboo tube, wherein the fiber direction of the bamboo tube is not interrupted in the tube sections (1) and the bent intermediate sections (2), so that conventional transitions located between the tube sections (1) can be replaced by means of the bent intermediate sections (2). Vehicle frame according to claim 1, wherein several of the tube sections (1) are joined together with intermediate sections (2) to form a ring, so that an endless frame tube (4) is provided. Vehicle frame according to claim 1 or 2, wherein the same is a bicycle frame. Vehicle frame according to claim 1 or 2, wherein the same is a cargo bike frame. Vehicle frame according to claim 1 or 2, wherein the same is a trailer frame (5). Vehicle frame according to claim 1 or 2, wherein the same is a wheelchair frame. Vehicle frame according to claim 1 or 2, wherein the same is a shopping cart frame. Vehicle frame according to claim 1 or 2, wherein the same is a rollator frame. Vehicle frame according to claim 1 or 2, wherein the same is a shopping trolley frame.

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