Coupling for securing a handlebar to a bicycle frame

A coupling for securing a handlebar to a bicycle frame, the coupling includes a compression nut and a bowl. An inner thread is formed in an upper end of the compression nut. A sealing ring has an outer thread formed on a lower end. The sealing ring is secured in place by a threaded engagement between the sealing ring and the compression nut when the handlebar standpipe is inserted through the sealing ring into the compression nut.

BACKGROUND OF THE INVENTION 
The present invention relates to a coupling, and more particularly to a 
coupling for securing a handlebar to a bicycle frame. 
As shown in FIG. 4, a conventional coupling for securing a handlebar to a 
bicycle frame comprises a washer W provided between a compression nut N 
and a bowl B, and a ball bearing A disposed in a bowl B. In order to 
maintain a good operational capability for the bearing A and to avoid a 
permeation of water into the bearing A, a sealing ring S is provided in an 
upper portion of the compression nut N. The sealing ring S has generally 
an O shaped cross section or a rectangular cross section. The sealing ring 
S is disposed in a groove formed in the compression nut N without support 
before a standpipe P can be inserted downward into the compression nut N. 
The inner diameter of the sealing ring S is smaller than an outer diameter 
of a standpipe P so as to make a water tight seal between the standpipe P 
and the compression nut N. Obviously, the standpipe P contacts and hits 
the sealing ring S before it can be inserted into the compression nut N. 
This causes problems during assembling processes. It may take several 
times for an assembler to insert the standpipe P into the compression nut 
N so that the sealing ring S is retained in position. 
The present invention has arisen to mitigate and/or obviate the 
afore-described disadvantages of the conventional sealing ring. 
SUMMARY OF THE INVENTION 
The primary objective of the present invention is to provide a coupling for 
securing a handlebar to a bicycle frame, in which a sealing ring is 
threadedly engaged to the upper end of a compression nut so that the 
sealing ring is secured in place when the standpipe passes through the 
sealing ring. 
In accordance with one aspect of the invention, there is provided a 
coupling for securing a handlebar to a bicycle frame, the coupling 
includes a compression nut and a bowl. An inner thread is formed in an 
upper end of the compression nut. The sealing ring has an outer thread 
formed on a lower end thereof. An annular blunt wedge is formed in an 
upper and inner end of the sealing ring. A threaded engagement between the 
sealing ring and the compression nut helps the sealing ring to be secured 
in place when the standpipe is inserted through the sealing ring into the 
compression nut. The blunt wedge makes a water tight seal between the 
standpipe and the compression nut. 
Further objectives and advantages of the present invention will become 
apparent from a careful reading of the detailed description provided 
hereinbelow, with appropriate reference to the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to the drawings and initially to FIGS. 1 and 2, a coupling for 
securing a handlebar to a bicycle frame in accordance with the present 
invention comprises a washer 12 disposed between a compression nut 1 and a 
bowl 18. A bearing 19 is disposed between the bowl 18 and an upper end of 
a frame fork 14. An inclined surface 10 is formed on an upper and outer 
surface of the compression nut 1. An inner thread 11 is formed in an upper 
end of the compression nut 1. An external thread 22 is formed on a lower 
end of the standpipe 21. 
The sealing ring 3 has an outer thread 31 formed on a lower end thereof. 
The outer thread 31 of the sealing ring 3 is threadedly engaged with the 
inner thread 11 of the compression nut 1. A first annular flange 32 which 
has a cross-section similar to a sharp wedge is formed on an upper and 
outer surface of the sealing ring 3. An upper surface of the first annular 
flange 32 of the sealing ring 3 has a slope equal to that of the inclined 
surface 10 of the compression nut 1 and is aligned with the inclined 
surface 10 so that water is guided to flow downward along the upper 
surface of the first annular flange 32 of the sealing ring 3 and the 
inclined surface 10 of the compression nut 1. A lower surface of the first 
annular flange 32 is level and contacts an upper surface of the 
compression nut 1. A second annular flange 33 which is generally shaped as 
a blunt angled wedge is formed on inner surface of the sealing ring 3. The 
inner diameter of the root portion of the second annular flange 33 of the 
sealing ring 3 is substantially equal to the outer diameter of the 
standpipe 21; and the inner diameter of the tip portion of the second 
annular flange 33 is slightly less than the outer diameter of the 
standpipe 21. 
Referring next to FIG. 3, a handlebar 2 is disposed on an upper end of the 
standpipe 21. When the standpipe 21 is inserted into the compression nut 
1, the lower end of the standpipe 21 first passes through the second 
annular flange 33 of the sealing ring 3, then, the external thread 22 of 
the standpipe 21 is threadedly engaged with the lower inner thread of the 
compression nut 1. After the lower end of the standpipe 21 is threadedly 
engaged with the inner thread of the bowl 18, the compression nut 1 is 
rotated to compress the bowl 18 so that the standpipe 21 is solidly 
retained in place by the bowl 18 and the compression nut 1. The standpipe 
21 is freely rotatable relative to the frame fork 14 with the assistance 
of the bearing 19. A threaded engagement between the outer thread 31 of 
the sealing ring 3 and the inner thread 11 of the compression nut 1 
assures that the sealing ring 3 will not be separated from the compression 
nut 1 when the standpipe 21 is inserted into the compression nut 1. The 
second annular flange 33 of the sealing ring 3 makes a water tight seal 
between the standpipe 21 and the compression nut 1. The external thread 22 
of the standpipe 21 has a length substantially equal to a length of the 
lower inner thread of the compression nut 1 plus the inner thread of the 
bowl 18 and a height of the washer 12 so that the sealing ring 3 
substantially embraces a smooth outer surface of the standpipe 21. 
Although this invention has been described with a certain degree of 
particularity, it is to be understood that the present disclosure has been 
made by way of example only and that numerous changes in the detailed 
construction and the combination and arrangement of parts may be resorted 
to without departing from the spirit and scope of the invention as 
hereinafter claimed.