The claimed invention relates to a construction of human-propelled transport vehicles, in particular, to a construction of bicycle and namely to a bicycle steering device.

In its technical essence, closest to the claimed solution is the bicycle steering device made in the following way. Inside the head tube of bicycle frame, the vertical rudder pintle is mounted in the rod of front fork in such a way as to allow its rotation. The handlebar stem, wherein the steering tube is fixed, is rigidly attached to the upper end of rudder pintle. The handlebar connected in such way with the front fork rotates clear in the headset resting on two ball-bearings which constitute a pivot connection and transfers the turn to the wheel, the axle of which is fixed in splits of front fork. [ 1 ]

The specified device has a serious disadvantage. The fork must rotate easily when bearings are normally fastened and have no axial rolling. If tightening is too close fitted, the steering control is impeded and if tightening is weak, the axial rolling may lead to bending of the rudder pintle and overdrawing. That is why the cycling under axial rolling of the front fork is absolutely inadmissible. But even if bearings are normally fastened, the rigidity of the system «fork - handlebar» is insufficient. During uphill cycling the handlebar is cushioning by few centimeters respectively to the fork in the area of grips at every treadling. This phenomena leads to an unproductive power input of cyclist («motion over resin» effect).

The task of the present invention consists in the increase in speed of bicycle motion and the stability enhancement on the move as well as in the assurance of cyclist safety on motion by way of increasing the degree of rigidity and reliability of the system « treadles - handlebar - wheels» by means of limitation of handlebar- turning extent.

The task in hand is completed by dint of the development of the steering device comprising a vertical rudder pintle mounted inside the head tube of bicycle frame in such a way as to allow its rotation in the rod of front fork as well as a handlebar stem attached to the upper end of rudder pintle and a steering tube fixed inside the handlebar stem and two struts positioned symmetrically about the rudder pintle, each of which being rigidly fastened on its upper part to the steering tube and on its bottom part to the fork.

The designed task is also completed through attaching the struts by means of clamps or welding.

The preferred embodiment of invention provides that said struts are made detachable.

Another embodiment of invention is characterized in that the struts are lengthwise adjustable. The change of struts length can be made by any of methods known to specialists.

The device may be applied to the bicycle construction provided with hard and soft fork.

The dimensions and the shape of struts may be optional and are to be chosen depending on the bicycle functionality: cruiser, mountain bike, tourer, racing bike, folding bike and so on. For example, the racing bike struts are made from an egg-shaped tube.

The Figure shows the construction of the claimed device.

Inside the head tube 1 of bicycle frame 2 the vertical rudder pintle 3 is placed in the rod of front fork 4. It is mounted on bearings (not shown in drawing) allowing rotation about the vertical axis and adjusting of bearings tightening. The handlebar stem 5 designed for mounting of the steering tube 6 is rigidly attached to the upper end of rudder pintle 3. The struts 7 are positioned symmetrically about the rudder pintle 3, being rigidly fastened on their upper parts to the steering tube 6 by means of clamps 8 and on their bottom parts to the fork 4 by means of clamps 9.

The device functions in the following way. When turning the handlebar the torque is transferred to the fork and the front wheel not only via the vertical rudder pintle 3 but via struts 7, this transfer via struts 7 being made to a greater extent because they have the larger torque arm than the vertical rudder pintle 3. Besides, the struts protect the steering tube against the cushioning shift respectively to the fork. As the consequence of this, the rigidity of the system «fork - handlebar» increases significantly and results in bicycle speed gain, increased bicycle stability in motion and improving cyclist safety. Concurrently, the problem of the handlebar turn extent limitation is solved and this also improves the safety of cycling.

References.

1. CnyTHH BEJlOCHITEflHCTA, A. H. JlionBKKaHeH, B. C. J emem o, JIEHH3^AT, 1960, page.67.