BICYCLE FRAME

CADRE DE BICYCLETTE

English Abstract

A bicycle frame includes a first support member having
a front end and a rear end. A head tube is secured in a
substantially vertical orientation to the front end of the
first support member. A seat tube is secured in a
substantially vertical orientation to the rear end of the first
support member. A second support member is spaced from the
first support member. A bottom bracket tube is supported by
the second support member in a substantially horizontal
transverse orientation in relation to the first support member.
Forks extend rearwardly from the second support member past the
seat tube. A hollow body connects the first support member and
the second support member. The body has spaced apart sidewalls
defining an open ended air flow passage that extends in
parallel spaced relation from the front end to the rear end of
the first support member.

Claims

5
THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A bicycle frame, comprising:
a first support member having a front end and a rear end;
a head tube secured in a substantially vertical
orientation to the front end of the first support member;
a seat tube secured in a substantially vertical
orientation to the rear end of the first support member;
a second support member spaced from the first support
member;
a bottom bracket tube supported by the second support
member in a substantially horizontal transverse orientation
relative to the first support member;
forks extending rearwardly from the second support member
past the seat tube; and
a hollow body connecting the first support member and the
second support member to maintain the first support member in
spaced relation to the second support member, the body having
spaced apart sidewalls which diverge away from the first
support member and converge toward the second support member
to define an open ended air flow passage that extends in
parallel spaced relation from the front end to the rear end of
the first support member.
2. The bicycle frame as defined in Claim 1, wherein sidewalls
are resilient thereby providing the body with shock absorbing
properties.
3. The bicycle frame as defined in Claim 1, wherein openings
are cut in the sidewalk of the body, thereby reducing the
weight of the body.

6
4. A bicycle frame, comprising:
a first support member having a front end and a rear end;
a head tube secured in a substantially vertical
5. orientation to the front end of the first support member;
a seat tube secured in a substantially vertical
orientation to the rear end of the first support member;
a second support member spaced from the first support
member;
a bottom bracket tube supported by the second support
member in a substantially horizontal transverse orientation
relative to the first support member;
forks extending rearwardly from the second support member
past the seat tube; and
a hollow body connecting the first support member and the
second support member to maintain the first support member in
spaced relation to the second support member, the body having
spaced apart sidewalls which diverge from the first support
member and converge toward the second support member to define
an open ended air flow passage that extends in parallel spaced
relation from the front end to the rear end of the first
support member, the sidewalls being resilient, thereby
providing the body with shock absorbing properties, openings
being cut in the sidewalls of the body, thereby reducing the
weight of the body.

Description

CA 02270336 2003-11-21
TITLE OF THE INVENTION:
Bicycle frame
NAME ( S ) OF INVENTOR ( S
Tim To
FIEhD OF THE INVENTION
The present invention relates to a bicycle frame.
BACKGROUND OF THE INVENTION
There is a trend in the manufacture of bicycles to move
to alternate designs for various components. The nature of
the alternate designs vary depending upon whether the object
is improved aerodynamics, making the component lighter,
enhancing strength, shock absorbing capability or other
properties. To this point in time there have been very few
2o alternative designs for the bicycle frame.
SU1~1ARY OF THE INVENTION
What is required is an alternative frame design.
According to the present invention there is provided a
bicycle frame which includes a first support member having a
front end and a rear end. A head tube is secured in a
substantially vertical orientation to the front end of the
first support member. A seat tube is secured in a
3o substantially vertical orientation to the rear end of the
first support member. A second support member is spaced from
the first support member. A bottom bracket tube is supported
by the second support member in a substantially horizontal
transverse orientation in relation to the first support
member. Forks extend rearwardly from the second support
member past the seat tube. A hollow body connects the first
support member and the second support member to maintain the
first support member in spaced relation to the second support

CA 02270336 2003-11-21
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member. The body has spaced apart sidewalls defining an open
ended air flow passage that extends in parallel spaced
relation from the front end to the rear end of the first
support member.
The bicycle frame, as described above, provides
aerodynamic performance with a free air flow through the body
reducing wind resistance.
1o
Although beneficial results may be obtained through the
use of the bicycle frame, as described above, further
refinements can be made to the design to improve performance
depending upon the performance qualities desired. Where the
comfort of the rider is of paramount concern, the sidewalls of
the body can be made from materials that have resilient
properties. This provides the body with shock absorbing
properties. Where strength is of concern, the sidewalls can
be made to diverge from the first support member to the second
2o support member providing a stable triangular structure. Where
weight is of concern, openings can be provided in the
sidewalls. This reduces the amount of material in the body,
thereby reducing its weight.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of the invention will become
more apparent from the following description in which
reference is made to the appended drawings, wherein:
FIGURE 1 is a front elevation view of a bicycle frame
constructed in accordance with the teachings of the present
invention.
FIGURE 2 is a front perspective view of the bicycle frame
illustrated in FIGURE 1.
FIGURE 3 is a rear perspective view of the bicycle frame
illustrated in FIGURE 1.
DETAINED DESCRIPTION OF THE PREFERRED E1~ODIMENT

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The preferred embodiment, a bicycle frame generally
identified by reference numeral 10, will now be described with
reference to FIGURES 1 through 3-
Bicycle frame 10 includes a first support member 12
having a front end 14 and a rear end 16. A head tube 18 is
secured in a substantially vertical orientation to front end
14 of first support member 12. A seat tube 20 is secured in a
substantially vertical orientation to rear end 16 of first
to support member 12. A second support member 22 is spaced from
first support member 12. A bottom bracket tube 24 is
supported by second support member 22 in a substantially
horizontal transverse orientation relative to first support
member 12. Forks 26 extending rearwardly from second support
member 22 past seat tube 20. A hollow body 28 connects first
support member 12 and second support member 22 maintaining
them in spaced relation to each other. Body 28 has spaced
apart sidewalls 30 defining an open ended air flow passage 32
that extends in parallel spaced relation from front end 14 to
rear end 16 of first support member 12. Sidewalk 30 are
resilient, thereby providing body 28 with shock absorbing
properties. To increase the strength of body 28, it is
preferred that sidewalls 30 diverge from first support member
12 and converge toward second support member 22. It is also
preferred that openings 34 are cut in sidewalls 30 of body 28,
thereby reducing the weight of body 28. A suitable material
for the construction of bicycle frame 10 is titanium.
Titanium is widely used in high performance bicycle frames.
It is a metal with high fatigue resistance, is resistant to
3o corrosion and has a density lower than the density of many
other metals from which bicycle frames are constructed.
The use and operation of bicycle frame 10 will now be
described with reference to FIGURES 1 through 3. In bicycle
frame 10 sidewalls 30 of body 28 can flex. Bicycle frame 10
thereby acquires the properties of passive suspension and can
absorb shock resulting from the passage of the wheels of the

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bicycle over small obstacles or rough road surfaces. When
bicycle frame 10 is used under track racing conditions its
passive suspension properties enable the use of stiff
aerodynamic wheels with less loss of comfort to the rider.
When bicycle frame 10 is used for racing or tour bicycling on
roads, or under off-road conditions, its passive suspension
properties allow a cyclist to experience less fatigue
resulting from road shock.
1o It will be apparent to one skilled in the art that
modifications may be made to the illustrated embodiment
without departing from the spirit and scope of the invention
as hereinafter defined in the Claims.

Representative Drawing