Bicycle crankset

A bicycle crankset includes a chain ring, a sleeve, two bearing sets, two bearings, two fastening nuts, two rubber washers, a retaining washer, a tightening nut, and a crank arm provided with outer threads. The crankset is mounted on the crank arm by the sleeve in conjunction with the retaining washer and the tightening nut which is engaged with the outer threads of the crank arm. The two fastening nuts are provided with a circular groove for retaining the rubber washer which is semicircular in its cross section and is provided at both edges on the flat side with an angled corner to facilitate the inserting of the rubber washer into the circular groove of the fastening nuts.

FIELD OF THE INVENTION 
The present invention relates generally to a bicycle, and more particularly 
to a crankset of the bicycle. 
BACKGROUND OF THE INVENTION 
As shown in FIGS. 1 and 2, a bicycle crankset of the prior art comprises a 
chain ring 1, a sleeve 2, two bearing sets 3, two bearings 4, two 
fastening nuts 5, two rubber washers 6, a retaining washer 7, a tightening 
nut 8, and a crankarm 9. The crankset is fastened on the crank arm 9 by 
the tightening nut 8 which is engaged with the outer threads 10 of the 
crank arm 9. The two rubber washers 6 have a square cross section and are 
intended to be lodged in the circular groove 11 of the fastening nut 5 so 
as to bring about the dustproof and the waterproof effects. The fastening 
nuts 5 are provided with a lubricating grease, which prevents the rubber 
washers 6 from being lodged in the circular grooves 11 of the fastening 
nuts 5 with precision. The quality of the prior art bicycle crankset is 
thus seriously undermined. In addition, the assembly of the bicycle 
crankset of the prior art can not be done efficiently. 
SUMMARY OF THE INVENTION 
The primary objective of the present invention is to provide an improved 
bicycle crankset which is free from the deficiencies of the prior art 
bicycle crankset described above. 
In keeping with the principle of the present invention, the foregoing 
objective of the present invention is attained by a bicycle crankset 
comprising a chain ring, a sleeve, two bearing seats, two bearings, two 
fastening nuts, two rubber washers, a retaining washer, a tightening nut, 
and a crank arm. The two rubber washers have a semicircular cross section, 
which enables the rubber washers to be lodged with ease and precision in 
the circular grooves of the fastening nuts, thereby enhancing the 
efficiency of assembling the bicycle crankset. 
The foregoing objective, features and functions of the present invention 
will be more readily understood upon a thoughtful deliberation of the 
following detailed description of a preferred embodiment of the present 
invention with reference to the accompanying drawings.

DETAILED DESCRIPTION OF THE EMBODIMENT 
As shown in FIGS. 3-7, a bicycle crankset embodied in the present invention 
comprises a chain ring 21, a sleeve 20, two bearing seats 30, two bearings 
40, two fastening nuts 50, two rubber washers 60, a retaining washer 70, a 
tightening nut 80, and a crank arm 90 which is provided with a plurality 
of outer threads 91. The fastening nuts 50 are provided with a circular 
groove 51 for retaining the rubber washer 60. The crankset of the present 
invention is fastened with the crank arm 90 by means of the sleeve 20 in 
conjunction with the retaining washer 70 and the tightening nut 80 which 
is engaged with the outer threads 91 of the crank arm 90. 
The present invention is characterized by the rubber washers 60 which have 
a semicircular cross section 62, as shown in FIG. 7. In addition, the 
rubber washers 60 are provided at both ends of the diameter of the half 
circle thereof with an angled corner 61 which enables the rubber washers 
60 to be lodged in the circular groove 51 of the fastening nut 50 with 
ease and precision. Accordingly, the assembly of the bicycle crankset of 
the present invention can be done efficiently. 
The embodiment of the present invention described above is to be regarded 
in all respects as being merely illustrative and not restrictive. 
Accordingly, the present invention may be embodied in other specific forms 
without deviating from the spirit thereof. The present invention is 
therefore to be limited only by the scope of the following appended claim.