The present invention relates to an angle-adjustable bicycle handle assembly which can adjust a down angle of a bicycle handle.
Generally, a common bicycle is provided with two wheels, pedals for transmitting propulsive force to the wheels, a chain connected between one wheel and the pedal, a frame having a predetermined shape for rotatably supporting the wheels, a saddle installed on the frame, and a handle.
There have been known various types of handle structures, such as a handle structure for transmitting a treading force of a rider to the wheels at maximum by directing handle grips further downwards, as well as a horizontal handle structure to which the hands of a rider sat on the saddle reach within a short distance.
The type of a handle having either a horizontal structure or a curved structure depends on a user's use. The horizontal handle structure is not suitable for cycle racing or long-distance traveling, and also the curved handle structure is not appropriate to short-distance traveling such as conveying loads, etc. Particularly, a fixed riding posture may lead to muscular problems in waist, shoulder, and the like.
Recently, there has now spreaded a home bicycle having a propulsive structure and a handle structure as bicycle race. However, a manufactured handle is in a single fashion of either a horizontal type or a curved type. In case of a curved handle, it is not easy for housewives or beginners to ride freely. A fixed horizontal handle is not popular with users due to an unstabilized riding posture. To secure a stabilized posture in this structure, it is possible to adjust the height of a saddle, but not possible for users to bend or stretch their back so as to be suitable to their height.
The above problem can be easily solved if a single handle structure may be changed into a horizontal shape or a curved shape according to the user's height.
Japanese patent laid-open application No. Sho 58-209674 discloses an apparatus for adjusting an angle of a bicycle handle, in which two handlebars are divided into left and right handles at the top end of a steering shaft to adjust an up and down angle. The left and right handles could be adjusted upwards and downwards at the same angle since they are engaged with tooth portions.
In order to perform temporary locking after an up and down angle is adjusted, a protruding tooth is formed at the front end of the tooth portion, and a cover structure which is removably dispositioned at the front of the protruding tooth is provided.
Therefore, a tightening bar which is connected to the cover tooth passes through the end of the tooth, and then a cam is rotated by a predetermined assembly, thereby engaging with or releasing from the cover tooth.
A conventional locking structure with a pin-shaped cam forms a control panel which is connected to the tightening bar backward the bosses of the tooth, and interposes a rod-shaped cam connected to a lever between the control panel and a tightening bar. This is a structure that both ends of the cam are disposed between the tightening bar, and does provide no means for preventing eccentricity of the cam. Accordingly, this structure has a frequent breakdown and a drawback that it requires a considerable rotatable force when performing a locking or releasing operation with respect to an angled surface of the cam, even though smooth movement with regard to a curved surface thereof is provided, thereby entirely providing no smooth locking and releasing manipulation.
Also, in order to solve the above problem, Korean Utility Model Registration No. 91480 (Utility Model Publication No. 95-5336), which was registered by the same applicant, discloses a cam tightening structure, in which a tightening bar is pivotally installed at a hinged cam axle which is formed at the rear end of the tightening bar, and a control panel having a hooker is movably provided at the hinged cam axle.
However, since the control panel, being a moving means, is further extended to the rear end of the casing, there is inconvenience in use or appearance. Also, a tightening interval according to the movement of the cam depends a limited outer circumferential surface of the cam in Japanese patent laid-open application No. Sho 58-209674 and Korean Utility Model Registration No. 91480. Therefore, there are defects that a thickness of the cam should be increased so as to elongate a linear movement distance, and corresponding tooth portions should be moved together when locking or releasing the cam axle since the cam axle has no support part, by which disengagement between tooth portions occurs frequently and the left and right handles are not supported firmly.