Non-rotatable seat assembly

A seat assembly includes a seat tube in which a seat post is movably received therein which has a clamping member with a seat disposed thereto. The seat post has two plain portions defined diametrically opposite in an outer periphery thereof and the seat tube has two wedge-shaped recesses defined diametrically opposite in an inner periphery thereof so as to receive two wedge-shaped blocks therein. The seat post extends through a nut member which is threadedly mounted to the seat tube.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a seat assembly and, more particularly, to 
a seat assembly having a seat post which is not rotated in a seat tube of 
a bicycle. 
2. Brief Description of the Prior Art 
A seat assembly for a bicycle includes a seat post received in a seat tube 
of the bicycle and a clamping member disposed to an upper end of the seat 
post so that a seat is attached to the clamping member. Generally, the 
seat post is fixedly clamped by the seat tube so that the seat post is 
theoretically not rotatable within the seat tube. Unfortunately, in 
practice, the seat post is rotated within the seat tube when an impact is 
laterally applied to the seat. This is a troublesome problem especially 
most of the bicycle riders do not have tools with them. 
The present invention intends to provide an improved seat assembly for a 
bicycle to mitigate and/or obviate the above-mentioned problem. 
SUMMARY OF THE INVENTION 
In accordance with one aspect of the present invention, therein provided a 
seat assembly comprising a seat tube having a first end with two 
wedge-shaped recesses defined diametrically opposite in an inner periphery 
thereof and a second end with an end cap fixedly received therein. A seat 
post is movably received in the seat tube and has two plain portions 
defined diametrically opposite in an outer periphery thereof. A clamping 
member is securely attached to the seat post and two blocks are 
respectively received the wedge-shaped recesses and located between the 
plain portions and the first end of the seat tube. 
It is an object of the present invention to provide a seat assembly wherein 
a seat post thereof is not rotated within the seat tube. 
It is another object of the present invention to provide a seat assembly 
wherein a spring is disposed between the seat post and an end of the seat 
tube. 
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 EMBODIMENT 
Referring to the drawings and initially to FIGS. 1 through 3, a seat 
assembly in accordance with the present invention generally includes a 
seat tube 30 having a first end and a second end, the first end thereof 
having a first threaded periphery 31 defined in an outer periphery thereof 
and the second end thereof having a tubular member 40 and an end cap 36 
which is threadedly and fixedly received therein. An end member 20 is 
threadedly engaged with the first threaded periphery 31 of the seat tube 
30 and has two wedge-shaped recesses 21 defined diametrically opposite in 
an inner periphery thereof. A second threaded periphery 22 is defined in 
an outer periphery thereof. 
A seat post 10 is axially movable and received in the seat tube 30 and has 
two plain portions 11 defined diametrically opposite in an outer periphery 
thereof. A bottom member 101 is fixedly close a lower end of the seat post 
10 which has a clamping member 80 securely attached to an upper end 
thereof. The clamping member 80 is a well known part in a bicycle 
assembling field so as to securely connect to a seat (not shown). 
Two wedge-shaped blocks 12 are respectively received the wedge-shaped 
recesses 21 and located between the plain portions 11 of the end member 
20. A ring 25 is received in the end member 20 and rested on the two 
wedge-shaped blocks 12, a nut member 37 being threadedly engaged with the 
second threaded periphery 22 of the end member to press the ring 25 
downwardly to retain the two blocks 12 in position such that the seat post 
10 is not rotated in the seat tube 30. 
A spring 35 is received between the tubular member 40 is the second end of 
the seat tube 30 and the bottom member 101 of the seat post 10 so that the 
seat post 10 compresses the spring 35 when the bicycle is ridden on a 
rough road. 
Referring now to FIG. 4, the spring 35 is compressed by a downward movement 
of the seat post 10 when a shock is transmitted from the ground so as to 
provide a comfortable riding condition. The seat post 10 is limited to be 
rotated within the seat tube 30 by the two wedge-shaped blocks 12 received 
in the wedge-shaped recesses 21 so that even a lateral force or impact is 
applied to the seat, the seat will not rotated about the seat post 10. 
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.