Title of Invention

FOLDABLE BICYCLE

Abstract

The invention relates to a novel foldable bicycle with unique, innovative folding process, comprising a front twin frame, the front twin frame adapted to accommodate the front wheel such that the front wheel in the folded state glides through, the rear twin frame carries the rear wheel within it, the said frames are kept together by a set of clamps on one side and set of hinges on the other, the two wheels in the folded state are offset such that the bicycle can be towed with the front wheel.

Full Text

This invention relates to a bicycle. Further, this invention relates to product design and development of a new type of bicycle. Precisely this invention relates to a foldable bicycle. Background of invention The ensuing description traces the bicycle known in the art. The Foldable Bicycle is an invention which can be traced back to the 1950s.They were developed after the development of the small wheel sized bicycle and were initially nothing but simple modifications of the small sized bicycles. The problem of storing them when not in use is what popularised the foldable bicycle in the 1960s. For the next two decades there was minimal development in relation to foldable bicycles due to lack of interest developing new kinds of frames. The safety frame (V or the diamond frame) had become popular and manufacturers were busy improving transmission systems, gears and other components. It is only during the last decade and a half that interest in the foldable bicycle was revived since a lot of new frame materials were developed. One of the most popular folding bicycles available in the U.S. and the European markets is the Birdy, a typical small-wheeled bicycle. It is one of the most compact foldable bicycles produced commercially. It uses a suspension system and an aluminium frame and stem. The Strida designed at the Royal College of Art, London is meant to be used by suburban rail commuters and is an extremely compact and small sized foldable bicycle. Instead of the usual Chain-Sprocket transmission, it uses a Belt-Pulley system for noiseless transmission and easy carrying/ stowing. The Zero-G manufactured and marketed by Dahon Bicycles, Taiwan is one of the few large-wheeled commercial folding bicycles. However, it is only a simple modification of the existing mountain bicycle, where the diamond frame is cut in two points and the bicycle thence folds to half its original volume. It uses 24" inch tyres and an aluminium frame. Apart from the popular foldable bicycles listed above, there is another category of 'tumble-down' bicycles - detachable bicycles. The Co-Motion Bicycle Company, U.S.A. manufactures a full sized bicycle that can be completely disassembled in a few minutes time and can be packed for easy transportation. However, the re-assembly is a cumbersome process, which makes the bicycle less popular among bicycling enthusiasts. The bicycles known in the art invariably have the following constraints and limitations. The unavailability of 'good' large-wheeled folding bicycle is a major factor constraining the growth of the foldable bicycle market. Controlling a small-wheeled bicycle is more difficult than controlling a large-wheeled one and needs some practice before one can ride it normally. The high price of foldable bicycles makes them unviable and therefore, the market only caters to niche customers such as bicycle enthusiasts or collectors which should not however be the case. Inventors and manufacturers have not yet tried to establish the right mix between the folded size and the time taken for folding. The emphasis till date has been on achieving the minimum possible size, but then, the smallest foldable bicycle need not be the best foldable bicycle. A bicycle folding into a small volume invariably requires a lot of steps and as a result, a lot of time is consumed, which may in fact dissuade the user from folding it at all. Nearly all the foldable bicycles use special components such as polymer springs used by Birdy, special stem bearings used by Strida, etc. These non-standard parts are difficult to procure and hence tend to increase the price. These are the major constraints in the prior art bicycles. A major prohibitive factor that plagues the foldable bicycle is that riding it doesn't give the feel of riding a 'normal' bicycle. Also certain bicycles completely redefine the concept of bicycling such the Strida whose two wheels do not fall into one line in the riding condition. Riding a bicycle with offset wheels is difficult and needs to be learned and it is human nature to shun things that require learning and practice to master. Summary of the Invention: The solution proposed forms the subject matter of this invention. By virtue of the proposals incorporated in this novel bicycle, these constraints known in the art are overcome. The proposed concept is an attempt to set right the above mentioned limitations in present day models. The concept uses two sets of frames - front and rear. Each of these frames is a twin-frame. The concept design and the fabricated prototype are built on 26" tyres and use all standard parts, such as 5 geared transmission system with a single piece drive sprocket-axle set, pedals, chain and derailleur. The basic features and the building blocks of the proposed concept are as follows. Objects of Invention: The primary object of the invention is to invent a novel type portable bicycle. It is another object of the invention to invent a bicycle, which is sturdy, easily portable and long lasting. Various other objects of invention will be clear from the following description. Statement of the Invention: Foldable bicycle with unique, innovative folding process, comprising a front twin frame, the front twin frame adapted to accommodate the front wheel such that the front wheel in the folded state glides through, the rear twin frame carries the rear wheel within it, the said frames are kept together by a set of clamps on one side and set of hinges on the other, the two wheels in the folded state are offset such that the bicycle can be towed with the front wheel. Statement of Drawings: The invention will be described and dealt with reference to the drawings accompanying the specifications as follows. Fig 1 of the drawing shows in plan elevation and end view, the front twin frame of the bicycle. Fig 2 of the drawing shows in plan elevation, the rear twin frame of bicycle. Fig 3 shows the schematic representation of the following processes: Step 1 - Opening of the clamps Step 2 - Swinging the rear frames backward Step 3 - Opening of the front clamp Step 4 - Taking out of the safety pin Step 5_- Swinging of the front wheel into the front wheel frame Fig 4 shows the bicycle in the folded state with the back frame locked with the front frame by Velcro straps, the two straps with fasteners locking the fork with the front frame, the front straps being helpful in carrying the bicycle. Fig 5 being photographs of the unfolded and folded prototypes of the bicycle. Detailed description of the Invention: The proposed foldable bicycle essentially consists of two distinct frames - the front frame and the rear frame. The two frames are kept together by a pair of joints - a set of clamps on one side (Right) and a set of hinges on the other (Left). A distinctive feature of the frames is that they are Twin-frames, made of slender aluminium alloy bars. The front twin frame allows the front wheel to glide through in the folded position. The rear twin frame carries the rear wheel between it (see Figures land 2). The frame is totally made of aluminium alloy; the one most commonly used in the building and construction industry. This grade of aluminium is widely available and is also relatively cheaper than the other grades of aluminium alloys available. This variety of aluminium alloy has been chosen primarily because of its light weight and its and its high strength to weight ratio. Aluminium alloys are rust and corrosion free and are also fire proof. In addition, good information is available in literature on composition, manufacturing and selection of aluminium alloys as compared to materials such as Titanium Alloys or Fibre reinforced plastics. The frames are bound together by clamps (1) and opening the clamps, swinging the rear frame constitutes the first folding movement (2). The front tyre fork is also hinged and clamped to the steering column. When the clamp (3) and the safety pin near hinge (4) are taken off, the front fork along with the front wheel is free to move about the hinge (4). The front wheel is thence rotated (5) about this hinge (4) and sits encased between the front twin frame thus completing the folding process (See Fig 3). The bicycle in the folded state can be towed along on the front wheel. Here in the folded state, the two wheels are offset by a small amount, one on top of the other in such a way that only the front wheel touches the ground and hence the bicycle can be towed along on the front wheel In the folded state the bicycle can also be locked in position and with the help of Velcro straps provided for this purpose, can be carried around like a backpack. Care has been taken to distribute the weight so as to provide for easier back carrying (See Fig 4). A prototype with most of the features mentioned here has been fabricated and the full size-working prototype has been economically tested (see Fig 5). Salient features of the Invention: I. The use of the twin frames provides both rigidity to the bicycle and also helps in the folding process. The frames encase the wheels and the other components and hence provide for protection of the components in the folded state. The twin frames also provide stiffness and hence better performance in torsion and bending of the frame. Since stiffness is high, the frame can be built using lighter components. The stiffness and rigidity in the concept and the fabricated prototype have been verified by the use of Finite Element Analysis and other modern computer aided design (CAD) tools. II. The folding process is also one of the claims of the proposed solution. A two step folding process achieves around 60% volume reduction which is a substantial amount considering the ease of folding and the time required for it. The folding process is also intuitive enough for the user to feel encouraged to fold it after use. III. The proposed design is built on a scalable configuration. One has only to proportionately scale up and scale down frame sizes in order to use tyres of different sizes. Hence, the manufacturer and the designer need not worry about aspects such as strength and manufacturability while fabricating a scaled up or scaled down version of the bicycle. IV. The design makes use of 26" tyres, which is the maximum diameter available for a wheel. Foldable bicycles have so far avoided using 26" tyres since it hindered foldability and V. The proposed design is a versatile Unisex bicycle. Care has been taken in the design stage itself so that users of both sexes may use the bicycle. The frame extends only up to the knee height so that women riders may not be hindered in any way while using the bicycle. VI. The bicycle can also be carried as a back pack when not in use, in the folded state. The bicycle has been provided with locks and straps so that it may be carried on the back. Care has been taken so as not to make back carrying a cumbersome process. Proper load distribution and carrying ergonomics have been carefully studied and applied in practice. It is to be noted that an embodiment of the invention is described so as to explain the salient features of the invention. The invention is in no way limited to the embodiment referred herein. Within the scope and ambit of the invention, various amendments and modifications are permissible. The scopes of the claims are defined in the following description. We claim; 1. Foldable bicycle with unique, innovative folding process, comprising a front twin frame, the front twin frame adapted to accommodate the front wheel such that the front wheel in the folded state glides through, the rear twin frame carries the rear wheel within it, the said frames are kept together by a set of clamps on one side and set of hinges on the other, the two wheels in the folded state are offset such that the bicycle can be towed with the front wheel. 2. The foldable bicycle as claimed in claim 1 wherein both the front and rear twin frames are made of aluminum and the design is unisex, scalable and with 26" tyre based construction. 3. The foldable bicycle as described in the specification and as illustrated by way of drawings accompanying the specification.

Documents:

110-mas-2000- abstract.pdf

110-mas-2000- claims duplicate.pdf

110-mas-2000- claims original.pdf

110-mas-2000- correspondence others.pdf

110-mas-2000- correspondence po.pdf

110-mas-2000- description complete duplicate.pdf

110-mas-2000- description complete original.pdf

110-mas-2000- drawings.pdf

110-mas-2000- form 1.pdf

110-mas-2000- form 13.pdf

110-mas-2000- form 26.pdf

110-mas-2000- form 5.pdf