Referring to
As shown in
The head tube 40 extends integrally from a front end of the upper tube 20 and a front end of the lower tube 30. The upper tube 20, the head tube 40 and the lower tube 30 are disposed at a same plane P. The upper rib 26 of the upper tube 20 is parallel to the plane P. The lower rib 36 of the lower tube 30 is parallel to the plane P, too. The head tube 40 has a chamber 42 for receiving an upright tube 50 of a front fork (not shown), and two openings 44 communicating the chamber 42 with outside. The chamber 42 of the head tube 40 communicates with the chamber 22 of the upper tube 20 and the chamber 32 of the lower tube 30. The first inner tubes 24 each have an inside communicates with the chamber 42 of the head tube 40, and the second inner tubes 34 each have an inside communicates with the chamber 42 of the head tube 40, too.
The front frame 10 is manufactured by the following steps. First, abut the two first inner tubes 24 together and abut the two second inner tubes 34 together. Then wind multiple layers of pre-pregs around the two first inner tubes 24 to form the upper tube 20, and wind multiple layers of pre-pregs into the head tube 40 at the front end of the upper tube 20, and wind multiple layers of pre-pregs around the two second inner tubes 34 to form the lower tube 30. Finally, place the combination into a die (not shown) and inflate the two first inner tubes 24, the two second inner tubes 34 and the head tube 40 with high pressure air to make the two first inner tubes 24 (or two second inner tubes 34) join with the upper tube 20 (or the lower tube 30) tight on the one hand, and to make the upper tube 20, the lower tube 30 and the head tube 40 abut on the inner wall of the die on the other hand. Then cure the combination to form the front frame 10.
Since the front frame 10 is cured only once, there is no crack generated between the first inner tube 24 (or two second inner tubes 34) and the upper tube 20 (or the lower tube 30). The structure strength of the front frame 10 is improved. Besides, since the upper tube 20 has the upper rib 26 inside and the lower tube 30 has the lower rib 36 inside, the structure strength of the upper tube 20 and the lower tube 30 are improved. Under the premise that the structure strength of the front frame 10 is enough, the quantity of the pre-pregs used in the front frame 10 can be reduced such that the weight of the front frame 10 can be decreased. The weight of the front frame 10 of the present invention is further decreased since the front frame 10 does not have the cured tube 9 in the conventional structure. Therefore, the front frame 10 of the present invention can improve the drawback of the conventional structure and achieve the objective of the present invention.
In practice, the structure of the front frame 10 has other alternatives. For example, the extending direction of the upper rib 26 and the lower rib 36 can be changed according to user's demand. The upper rib 26 or the lower rib 36 may also not present. Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention.
Number | Date | Country | Kind |
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95213022 | Jul 2006 | TW | national |