Industrial Technology Research Institute

Gou-Don Chu

Chin-I Lin

Rong-Shian Liu

Chung-Lin Wu

Yu-Hsuan Chen

Chin-l Lin

A composite legal type bicycle frame is disclosed which contains a front frame portion and a rear frame portion. The front frame portion contains a central main and a plurality of legs for connecting the central main with various components of the bicycle, and the rear frame portion contains a rear fork, which consists of a left rear branch and a right rear branch. The left and right rear branches are first cured and glued together at respective abutting surfaces thereof to form an integral rear fork before they are adjoined with the front frame portion, via prepregs and using a cocuring procedure. The left and right rear branches are formed to contain cross-shaped matching protrusion and recess, respectively, on the abutting surfaces thereof, so as to enhance the integrity of the integral rear fork. As a result, a great flexibility of design options can be obtained. For example, the rear fork can be connected to one of the legs but not to the central main. Also, the front frame portion can be designed such that one of the legs is connected indirectly to the central main via another leg, and not directly connected to the central main.

Method of making a single rear fork bicycle frame

A mandrel assembly has a hollow main tube and two annular sleeves, wherein an inner diameter of the two annular sleeves is larger than an outer diameter of the two main tube ends. The two annular sleeves are sleeved respectively on the two main tube ends, which can be easily disengaged from the mandrel assembly when applied with an external force.

Method of forming composite articles using a mandrel assembly

Mandrel assembly

A composite bicycle frame containing a hollow slanted-Y-shaped front frame portion, a hollow upper support paw and a hollow lower support paw. The hollow slanted-Y-shaped front frame portion comprises: (1) a generally common junction; (2) a main tube connected between the front fork assembly of the bicycle and a middle portion of the common junction in a slanted manner; (3) an upper branch tube connected between the seat assembly of the bicycle and an upper portion of the common junction in a slanted manner; and (4) a lower branch tube connected between the pedal support assembly of the bicycle and a lower portion of the common junction in a slanted manner. The hollow upper support paw is connected between the seat assembly and the rear wheel shaft assembly of the bicycle, and the hollow lower support paw connected between the pedal support assembly and the rear wheel shaft assembly. A set of generally hollow front, seat tube and bottom bracket junctions are provided for connecting, respectively, (1) between the hollow main tube and the head tube, (2) among the hollow upper branch tube, the seat tube sleeve, and the upper support paw, and (3) among the hollow lower branch tube, the bottom bracket tube, and the lower support paw. Each of the hollow tubes, paws, and junctions comprises at least a fibrous material impregnated with a synthetic resin, and these tubes, paws, and junctions are integrally united by overlapping edges of the resin impregnated fibrous material. The upper support paw and the lower support paw are connected to the rear wheel assembly at opposite sides thereof, with the upper support paw being disposed at the same side as the drive chain of the bicycle. This allows great flexibility to be obtained in designing bicycle chain related components, such as the crank set assembly and the rear derailleur assembly.

Composite bicycle frame with y shaped tubular configuration

Bicycle frame

Growing community of inventors

Hsinchu, Taiwan

Gou-Don Chu