Headset for a bicycle

A headset for a bicycle includes an upper bearing assembly and a lower bearing assembly between which is disposed a head tube and a steerer tube is inserted through head tube and rotatably engaged between the two assemblies. The upper bearing assembly has a bearing with a plurality of rollers each roller is disposed in an inclined fashion by 10-20 degrees regarding to a vertical line of said assembly.

BACKGROUND OF THE INVENTION 
The present invention relates to a headset for a bicycle, and more 
particularly to a headset which has an upper bearing assembly and a lower 
bearing assembly each bearing having a plurality of rollers disposed in an 
inclined fashion therein and the inclined angle regarding to a vertical 
line of the rollers is 10-20 degrees for the upper bearing assembly and 45 
degrees for the lower bearing assembly respectively. 
Referring to FIG. 1, a conventional headset of a bicycle generally includes 
an upper bearing assembly 50 and a lower bearing assembly 60 between which 
a head tube 70 is disposed. A steerer tube 80 is inserted from the lower 
bearing assembly 60 via the head tube 70 to the upper bearing assembly 50 
and is threaded engaged to an adjusting nut 51 disposed on a top of the 
upper bearing assembly 50 such that the steerer tube 80 is rotatably 
engaged between the upper and lower bearing assemblies 50, 60. Each 
bearing assembly has a first race 501 or 601 and a second race 502 or 602 
which respectively abut a first bowl 52 or 61 and a second bowl 53 or 62. 
A bearing 503 or 603 is securely engaged between the first and second 
races 501, 502 or 601, 602, generally, the bearings 503, 603 are disposed 
by the same inclined angle of 45 degrees regarding to a vertical line of 
respective assembly 50, 60. The upper and lower bearing assemblies 50, 60 
require different installing standards, namely, the upper bearing assembly 
50 requires less rotating feature than the lower bearing assembly 60 
because the lower bearing assembly 60 is designed for providing a smoothly 
rotating feature for the steerer tube 80, however, the upper bearing 
assembly 50 is required to hold and maintain the head tube and the two 
assemblies 50, 60 in place rather than to provide a smoothly rotating 
feature. Therefore, because of the similarity in design of the two 
bearings 503, 603, when an assembler rotates the adjusting nut 51, a 
vertical component force will transfer to the lower bearing 603 and the 
larger the vertical component force is produced the less rotating feature 
of the lower bearing 603 performs, and the larger the angle of the bearing 
disposed regarding to the vertical line the larger the vertical component 
force will be produced, this is opposite to the principle of the features 
required of the bearings 503, 603 mentioned above. Should the lower 
bearing 603 rotate unsatisfactorily, the assembler must loosen both the 
upper and lower bearing assemblies 50, 60 and re-check them again. 
The present invention intends to provide a headset where the upper bearing 
has a plurality of rollers disposed therein in an inclined fashion, the 
inclined angle is 10-20 degrees regarding to a vertical line and by which 
a less vertical component force will be produced when assembling the upper 
bearing assembly therefore mitigating and/or obviating the above-mentioned 
problems. 
SUMMARY OF THE INVENTION 
The present invention provides a headset for a bicycle includes an upper 
bearing assembly and a lower bearing assembly between which a head tube is 
disposed and a steerer tube is inserted through head tube and is rotatably 
engaged between the two assemblies. The upper bearing assembly has a 
bearing with a plurality of rollers each roller is disposed in an inclined 
fashion by 10-20 degrees regarding to a vertical line of said assembly. 
It is an object of the present invention to provide a headset having an 
upper bearing with a plurality of inclined rollers by 10-20 degrees 
regarding to a vertical line. 
It is another object of the present invention to provide a headset whose 
upper bearing assembly transfers less vertical force to its lower bearing 
assembly when the upper bearing assembly is adjusted. 
Other objects, advantages, and novel features of the invention will become 
more apparent from the following detailed description when taken in 
conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to the drawings and initially to FIG. 2, a headset in accordance 
with the present invention generally includes an upper bearing assembly 30 
and a lower bearing assembly 40 between which a head tube 80 is disposed. 
A front fork 90 is inserted from the lower bearing assembly 40, by a 
steerer tube 91 thereof, via the head tube 80 to the upper bearing 
assembly 30 and is threadedly engaged to an adjusting nut 33 disposed on a 
top of the upper bearing assembly 30 such that the steerer tube is 
rotatably engaged between the upper and lower bearing assemblies 30, 40. 
The upper bearing assembly 30 includes first and second races 31, 32, a 
bowl 34 and a bearing disposed between the first and second races 31, 32, 
the lower bearing assembly 40 includes first and second races 41, 42, 
first and second bowls 43, 44 and a bearing disposed between the first and 
second races 41, 42. The upper bearing of the upper bearing assembly 30 
includes a plurality of rollers 10 which are disposed therein in an 
inclined fashion by an angle 10-20 degrees regarding to a vertical line of 
the assembly 30. The lower bearing of the lower bearing assembly 40 also 
includes a plurality of rollers 20 which are disposed therein in an 
inclined fashion by the same angle as the conventional, that is 45 degrees 
regarding to a vertical line of the lower bearing assembly 40. 
Further referring now to FIGS. 2 and 3, the adjusting nut 33 has an outer 
tapered surface 330 formed on a skirt portion thereof, the tapered surface 
330 having the same inclined angle as the inclined angle of the rollers 10 
of the upper bearing and contacting the rollers 10. When a user or an 
assembler adjusts the upper bearing assembly 30 by rotating the adjusting 
nut 33, the tapered surface 330 exerts a force (F) vertical to a periphery 
of the first race 31 and roller 10 thus pulls the steerer tube 91 up and 
the head tube 80 and the lower bearing assembly 40 are securely engaged 
between the front fork 90 and the upper bearing assembly 30. The force (F) 
is composed by a vertical component force FV which will be transferred to 
the lower bearing, and a horizontal component force FH, the quantity of 
the force FV is derived by the arithmetic relationship FsinA wherein A is 
the inclined angle regarding to the vertical line. Since the angle A is 
10-20 degrees and is less than 45 degrees, in the inclined angle of the 
conventional upper bearing, therefore, the FV is less than that of the 
conventional. This means that the upper bearing can be securely disposed 
by rotating the adjusting nut 33 while the lower bearing still maintains 
its excellent rotating feature. 
Accordingly, the headset in accordance with the present invention provides 
an improvement assembling feature in which the adjusting of the upper 
bearing effects less the rotating feature of the lower bearing. 
Although the invention has been explained in relation to its preferred 
embodiment, it is to be understood that many other possible modifications 
and variations can be made without departing from the spirit and scope of 
the invention as hereinafter claimed.