Bicycle frame with channel member

A bicycle frame using in combination with tubing elements a main channel frame member. The main load carrying member of the frame is an inverted "U" shaped section, or channel section which is tapered in both the horizontal plane and the vertical plane from the front of the bicycle frame to the rear of the bicycle frame (depth and width of the frame member increases from the front to the rear). A head tube is joined to the front of the channel frame, a seat mast tube runs through the middle portion of the channel frame member, and is anchored to the web of the channel frame, and a down tube extends from the top part of the head tube through the web of the channel section between the head tube and the seat mast tube to the lower portion of the seat mast tube where it is affixed to the seat mast tube, or to the bottom bracket. Optionally, further diagonal bracing elements can extend from the top of the seat mast tube to the back of the frame to connect to the channel frame member at either side of a rear wheel. In another alternative embodiment the optional diagonal bracing tubes are replaced with shock absorbing members, and the channel is provided with a hinge to provide a suspension for the rear wheel.

BACKGROUND AND PRIOR ART 
This invention relates to bicycle frames. More particularly, this invention 
relates to a bicycle frame designed to provide improved handling and 
control characteristics. 
In the past bicycle frames had been constructed of tubular members, either 
straight or curved, joined together to form a completed unit. Even racing 
bicycles, remain derivative of the classic diamond tubular frames. 
Even special types of sports bicycles called BMX or free style bikes 
utilize variations on a diamond frame of triangulated tubular members. 
Features desired in racing or sport bicycles are good handling, light 
weight, power train rigidity, and a low center of gravity. Features 
particularly desireable in BMX or sport-type free style bicycles is a 
standing platform or standing platforms, which are used for performing 
trick maneuvers. For these trick maneuvers it is desireable to have 
uncluttered standing room behind and below the seat and between the seat 
and the handle bars. Examples of such standing areas are shown in the GT 
Pro Series in red line BMX bikes illustrated on pages 6, 7, 8 and 9 of the 
March 1986 BMX Action Magazine. 
Although there are conflicting theories and approaches to bicycle frame 
design, which remains as much an art as it is a science, one theory holds 
that frame stiffness directly corresponds to the efficiency of the power 
transmission from the rider's legs to the ground. Bicycles are subjected 
to reciprocating pedaling force, and standard bicycle designs with chain 
stays and seat stays, and in general, the diamond frame comprising tubular 
members welded or brazed together with or without lugs, is subject to a 
certain amount of distortion or deflection when subjected to the 
reciprocating periodic forces from the rider's legs pushing down on one 
side of the frame which is countered by the rider's grip upon the handle 
bars which pulls upward on the opposite side from the downward force. 
Although the deflection is somewhat spring like, there is an energy loss 
as not all of the energy is recaptured from the spring. 
Stiffness is especially important in racing bicycle designs, and in 
off-road or trick bicycle designs. Racers, particularly when climbing or 
sprinting, lean the bicycle into the power leg up to 15.degree., 
increasing the need for lateral stiffness. Further, even minute energy 
losses add up, and in consideration of the length of some bicycle races, 
accumulative effects of such energy losses could be determinative of the 
outcome of the race. 
Further evidence of the importance of fractional gains in efficiency can be 
seen in the radical frame and accessory designs seeking aerodynamic gains 
used in bicycles used for sprinting and professional races, such as the 
Tour de France. A change as simple as a different handle bar design was 
credited with providing the margin that allowed professional racer Greg 
LeMonde to win the 1989 Tour de France. See Sports Illustrated Vol. 71 No. 
27, Dec. 25, 1989-Jan. 1, 1990. The Tour de France is an example of a long 
professional race where great sums of money are at stake, and fractional 
gains can add up to the difference between winning and losing over more 
than three (3) weeks of stage races, during which the riders cover an 
excess of 2,000 miles over widely varying terrain. 
World class amateur and professional sprinters and bicycle racers are 
tremendously fit and can exert forces upon racing frames far greater than 
those of a recreational rider. The same is true for BMX and off-road 
bicycle riders whose bicycle frames are subjected to severe impact loads 
from jumps and bumps, both during recreational and racing. 
The bicycle frame of the present invention can be configured to any wheel 
base, wheel diameter, head tube angle, seat tube angle, wheel width, rider 
weight, or specific use by varying the frame dimensions and/or materials 
as will be further described below. The frame design of the present 
invention utilizes a channel frame main member in combination with the 
seat tube, head tube and down tube used by diamond configured tubular 
frame designs. In comparison to the diamond configured tubular frame 
designs the present invention is lighter in weight which translates to 
lower energy demands, easier climbing, increased traction and road 
holding, and better handling in general. In addition, the channel member 
of the present frame design can easily be provided with means for mounting 
numerous accessories mandated by particular bicycle uses, or popular with 
racers and recreational riders. The flat sides of the channel frame 
provide easy mounting for derailleurs, and provide a protective enclosure 
for the power transmission components of a bicycle by covering the top of 
the chain sprocket at the crank, and by almost completely enclosing the 
rear hub or derailleur components. Optionally, standard derailleur 
components could be mounted to the outside face of one of the channel legs 
by a simple bolt on connection. 
The channel frame components could also be injection molded or thermal 
molded from plastic materials for use in much smaller scale bicycles or 
tricycles for children and beginners. The protective covering over the 
drive chain, and the qualities of light weight, low center of gravity and 
good handling are equally important for beginners. 
SUMMARY OF THE PRESENT INVENTION 
The new and improved bicycle frame design presented herein eliminates a 
number of tubular parts, and replaces these with a single channel shaped 
load bearing member. The front part of the main channel frame member may 
be further reinforced by a tubular member exiting from the crank housing, 
or bottom bracket, and running to a connection at the upper portion of the 
head tube. This member intersects and is connected to the main channel 
frame member at a point intermediate the head tube and the seat mast. 
Specific frame design features are that the main load carrying member ("u" 
shaped section or channel section) is tapered both in the horizontal plane 
and the vertical plane from the front of the bicycle frame to the rear of 
the bicycle frame. Depth and width increases from the front to the rear to 
absorb loads imposed by the rider. The front part of the channel is also 
wrapped around the lower portion of the head tube additionally reinforcing 
the lower part of the head tube and the connection of the main channel 
frame member to the head tube. 
A seat mast tube is secured to a traditional bottom bracket housing and 
extends vertically upward through and is securely attached to the web of 
the channel section. 
A down tube is also secured to the bottom bracket and intersects and is 
secured in place to the web of the channel section between the seat mast 
tube and the head tube. This down tube is then also secured to the upper 
portion of the head tube to further reinforce the head tube. 
Diagonal reinforcement tubular members are optionally attached to the upper 
portion of the seat mast, and triangulated to the rear of the frame where 
they are secured to portions of the frame rear-ward from the seat mast for 
additional load carrying ability.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
This invention relates particularly to bicycle frames for improved handling 
and control due to the rigidity of the frame. This is especially 
desireable for certain types of racing and trick, or performance bicycles 
subjected to high power transfer or sudden impacts and bumps. The frame 
design resists sudden impacts and torque loads. 
A high efficiency bicycle frame design and the importance of such a design 
for racing purposes is disclosed in U.S. Pat. No. 4,500,103 issued on Feb. 
19, 1985 to Gary G. Klein. The Klein reference further discloses various 
suitable manufacturing techniques and materials, and the Klein reference 
is hereby fully incorporated by reference for all that it discloses. 
U.S. Pat. No. 4,666,175 issued May 19, 1987 to Clifford F. Mueller 
discloses the desirability of certain frame designs providing standing 
platforms for trick manuevers. The Mueller reference also discloses the 
importance of providing suitable locations for necessary components, such 
as derailleurs, springs and sprockets and brakes for an uncluttered design 
which also protects the components. The Mueller patent is hereby 
incorporated by reference for all that it discloses. 
The new and improved frame design of the present invention provides light 
weight, low center of gravity, good handling characteristics, and an 
efficient power train platform strong enough for rough use, such as in BMX 
or off-road riding and racing. The improved frame design of the present 
invention also provides for manufacturing economies, the channel member is 
an efficient design which can be inexpensively and quickly mass produced. 
Connections of the tubular members to the main channel frame member are 
both fewer and simpler to make than the traditional welding and/or brazing 
tube and lug designs that predominate the art of designing and 
manufacturing bicycle frames. 
Referring to FIG. 1, there is illustrated in perspective view the frame 
design of the present invention. The component parts comprising the frame 
design will now be described with reference to FIG. 1, and referenced 
numerals for each of the component parts will be repeated in the following 
figures. 
FIG. 1 is a perspective view of the present invention. Reference numeral 1 
indicates the main channel frame structural member of the bicycle frame of 
the present invention. Numeral 2 indicates the head tube, numeral 3--the 
seat mast tube, numeral 4--the down tube, numeral 5--the bottom bracket, 
and numeral 6 indicates two longitudinal diagonal brace members which are 
used on an alternative embodiment of the present invention. 
Also shown in FIG. 1 are the front and rear wheels 7, and the front fork 8. 
Not shown are the handle bars and handle bar stem assembly for steering 
and the power transmission means which, in the preferred embodiment, would 
comprise a set of cranks and sprockets mounted to the bottom bracket 5, 
provided with a chain, also not shown, running to either a rear derailleur 
assembly, or a coaster hub assembly with or without additional gears. 
In a primary embodiment a bicycle frame in accordance with the present 
invention has been constructed with the foregoing described and 
illustrated components wherein both the seat mast tube 3 and the head tube 
2 are oriented at 90.degree. angles, 9 and 10 respectively from the face 
11 of the main member 1. FIGS. 3 and 8. It is known in the art of bicycle 
frame design that the handling characteristics of a bicycle can be varied 
by changing such variables as wheel base, the head tube angle/fork rake, 
and the amount of trail which, for the purposes of this disclosure, will 
be understood to mean the distance the front fork puts the axis of the 
front wheel ahead of the longitudinal axis of the head tube. A specific 
embodiment (illustrative only) in accordance with the present invention 
uses a head tube angle (defined as the angle between the horizontal and a 
line coinciding with the longitudinal axis of the head tube) of 71.degree. 
and 30 minutes. 
Referring now to FIGS. 4, 5, and 6, illustrated in various cross-sections 
is the channel member of one embodiment of the channel frame bicycle 
design of the present invention. The locations of these cross-sections are 
indicated in FIGS. 3 and 8. The channel frame comprises a web 12 and two 
legs or walls 13 and 14, which in the primary embodiment are oriented 
90.degree. from the web 12, and project downward one each from each side 
of the web 12. The web 12 presents an upper exterior face 11, and a lower 
interior face 15. The web is narrower at the front and tapers outwardly to 
widen at the back, and both legs or walls are shorter at the front and 
taper lengthening toward the rear. Although the primary embodiment 
illustrates a channel section tapering in both the horizontal and vertical 
planes (if the web is oriented horizontally) from the front of the bicycle 
to the rear of the bicycle, alternative embodiments could utilize a 
channel section of uniform width and depth, or other channel type 
configurations than that illustrated here, such as an I-beam type cross 
section which also could either be varied in width and depth from the 
front of the bicycle to the rear, or could be of uniform width and depth. 
The primary embodiment would be that illustrated for reasons set out more 
fully below. 
FIGS. 7, 8, 9, 10 and 11 illustrate various views of one embodiment of the 
present invention that is illustrated in perspective in FIG. 1. FIGS. 2, 
3, 9, 10 and 11 illustrate like views of an alternative embodiment, one 
without the diagonal frame support members 6. The following description, 
except where specifically referring to the diagonal support element 6 
should be interpreted to cover both illustrated embodiments. 
The basic design of the tapered channel frame element 1 has previously been 
described. It is envisioned that this channel frame member will be 
manufactured by cutting, stamping, or punching triangular shaped blanks 
(FIG. 12) from a flat sheet of T6061 aluminum, and either concurrently or 
as a subsequent step, press forming or stamp forming the flat sheets 
positioned over a press mold to ben the sheets into the channel section 
tapered taper from the front to the back in both vertical and horizontal 
dimensions. For example, a semi-triangular shape such as illustrated in 
FIG. 12 could be punched out of a sheet of 3/8 in. thick T6061 aluminum. 
The semi-triangular shape, illustrated in FIG. 12, is provided with four 
slots or cut-outs which can either be formed or fashioned or punched into 
the aluminum sheet as the semi-triangular shape is stamped out, or the 
slots can be cut out in the appropriate locations after the 
semi-triangular sheet is formed. Reference numerals 11, 12, 13 and 14 as 
referenced to FIG. 12 and the dashed lines from front to back of the 
semi-triangular shape indicate the top face 11 of the web 12, and the left 
13 and right 14 legs of the channel respectively. The channel section 
comprising web and two legs as illustrated in FIGS. 4, 5 and 6 can be 
formed as a subsequent step or steps after the triangular or 
semi-triangular shape is fashioned, or they can be formed concurrently as 
part of an automated cutting shaping or press molding step. 
The slots referred to previously are as follows: a head tube slot 16, a 
rear wheel slot 17, the left rear axle notch 18, and the right rear axle 
notch 19. FIG. 12. These slots are also indicated in FIGS. 4, 6, 2, 3, 7, 
8, 9, 10 and 11 by like reference numerals. 
Also illustrated in FIGS. 12 and 3 is a mounting bracket tab for mounting a 
rear derailleur. The tab 20 is drilled and tapped for a mounting bolt as 
are standard rear drop-outs known in the art. The mounting bracket 20 is 
drilled with a hole 21 which is tapped and threaded for a mounting bolt 22 
as is common in the art. FIG. 8 illustrates an alternative arrangement for 
a mounting tab 20 and the left and right rear axle slots 18 and 19 
respectively for mounting the rear wheel to the channel frame member. The 
dash line areas in FIGS. 4 and 6 indicate the locations of the rear wheel 
slot 17, and the left and right rear axle slots 18 and 19 respectively. 
Two tabs 23 and 24 projecting past the circumference of the head tube 
where it will be mounted, which is indicated by dash lines in FIG. 12, are 
used to further secure the head tube in place and brace the head tube, as 
the head tube is mounted into the front head tube cut-out 16, the two tabs 
23 and 24 are wrapped around the front of the lower portion of the head 
tube section and welded top and bottom, and welded or otherwise connected 
down the jointing or mating seam of the two tab 23 and 24 to further 
secure and brace and support the head tube against impact and torque 
loads. 
Although as mentioned, the relative geometry of the interconnected 
components of the bike frame can be modified to vary the handling and 
performance characteristics of a given bike, and to fit the intended used 
of a given bike, and to fit the physical characteristics of a given rider. 
A specific embodiment in accordance with the invention suitable for use as 
a BMX or free style sport type bike would utilize a channel frame member 
33 and 7/8 in. in length, measured from the end most portion of the 
channel frame to the longitudinal axis through the head tube. As mentioned 
previously in the primary embodiment, both the head tube 2 and the seat 
mast 3 are oriented at 90.degree. angles 10 and 9 respectively relative to 
the upper face 11 of the web 12 of the channel frame member. The distance 
between the head tube 2 and the seat mast tube 3 measured from the 
longitudinal axis of one to the longitudinal axis of the other is 181/4 
in'. 13/8 OD aluminum tubing is used for the head tube, and 11/8 in. OD 
aluminum tubing is used for the seat mast tube 3 and the down tube 4. The 
overall longitudinal length of the head tube is 61/4 in's. As previously 
mentioned, the head tube is fitted into slot 16 at the front of the shaped 
channel member, the two tabs 23 and 24 are wrapped around the head tube as 
illustrated in FIGS. 2, 3, 7, 8, 9, 10 and 11 to tabs 23 and 24 are cut to 
exactly fit around the outer circumference of the head tube 2, and are 
there butt welded together down the vertical seam at the very front of the 
channel frame member. A fillet weld 25 is then made all 360.degree. around 
the head tube at the intersection of the base of the head tube, and the 
top face 11 of the web 12 of the channel member 1. FIGS. 3 and 8. A second 
360.degree. weld 26 is placed at the head tube intersection with the 
forward projecting tabs 23 and 24, the side walls 13 and 14, and the lower 
face 15 of the web 12 of the channel member. FIGS. 3 and 8. In this 
specific illustrative embodiment the lower portion of the head tube is 
fixed to the front cut-out 16 provided at the front of the channel member 
so that a stub of head tube 26 projects below the channel member. In this 
specific illustrative embodiment the measurement from the top face 11 of 
the channel member to the very lowermost portion of the stub 26 measured 
parallel to the longitudinal axis of the head tube 2 measures 13/8 in's. 
In this specific illustrative embodiment the semi-triangular shape stamped 
or cut from the aluminum sheet measures 337/8 in's. from the most 
rear-ward portion to the center line of the location of the head tube 2 as 
it fits into the cut-out notch 16. Prior to forming the channel sections 
illustrated in FIGS. 4, 5, and 6, the total width of the semi-triangular 
shape of the specific embodiment measures 10.312 in's. at the most 
rear-ward portion of the shape, or at the left of FIG. 12, the total width 
of this semi-triangular shape measured at a point 10 in's. towards the 
front from the left-ward portion of FIG. 12 is 8.187 in's., and the width 
across the triangular shape measured at a point 20 in's. toward the front 
from the left is 5.812 in's. 
The shape is stamped or roll formed or molded, or otherwise fashioned into 
the channel sections illustrated in FIGS. 4, 5 and 6, preferably with 
interior corners on a 1/4 in. radius. This gives interior width for the 
channel sections of 4 15/16 in's. at the rear or left most portion of 
FIGS. 2, 3, 7, 8, 9, 10 and 11, 4 1/16 in's. at the point 10 in's. from 
the rear, or left of the referenced FIGS., and 2 15/16 in's. at the point 
20 in's. from the rear, or left most portion of the referenced FIGS. 
The depth of the channel section therefore for the specific illustrative 
embodiments at these locations measured from the top face 11 of the web to 
the lower most portion of the channel legs 13 and 14 is 2 15/16 in's. at 
view 6, which is the rear-ward most portion of FIGS. 2, 3, 7, 8, 9, 10 and 
11; 2 1/16 in's. at view 4 a section 10 in's. from the left most portion 
of FIGS. 2, 3, 7, 8, 9 and 10; and, 1 7/16 in's. at section 5, FIG. 5 
which is a section 20 in's. from the left or rear-ward most portion of 
FIGS. 2, 3, 7, 8, 9 and 10. 
This is a specific illustrative embodiment, and the invention is not to be 
understood to be limited to the dimensions set out, as indicated the 
variations can be made in dimensions, materials, and the geometry of the 
connected members to suit specific purposes or individuals. 
Also shown in FIG. 12 are openings 26 and 27 which can be punched or formed 
in the semi-triangular shape at the same time the notches 18, 19, 16 and 
17 are formed. Opening 26 is provided at the appropriate location for 
mounting the seat mast tube 3, and opening 27 is provided for passage of 
the down tube 4 through the upper surface of the web 11. Manufacturing 
advantages will be realized by forming all of these openings in an 
automated manner to precisely locate and orient the openings which will 
simplify the assembly of the components into a frame. For instance, the 
opening 26 can be formed at the desired angle (27.degree. in the specific 
illustrated embodiment) so that when the down tube is placed through the 
surface of the web it can only be placed at the correct angle and 
alignment relative to the web of the channel frame member. This will 
eliminate or reduce the need for a jig to align such components during the 
assembly in connection of the various components of the frame. In 
addition, forming the opening 27 at the appropriate angle, corresponding 
with that desired for the down tube makes for better welding practice, 
therefore a joint that is structurally sounder. 
Mounted to the lower portion of the seat mast tube 3 is a bottom bracket 
housing or mount 5. Although alternative configurations are used in the 
art, a bottom bracket essentially provides a mounting or housing for a 
power transmission means, or portions of the power transmission means 
(such as pedals, cranks and chain wheels). Pedals are connected to an axle 
passing through the housing transverse to the longitudinal axis of the 
bicycle frame, and the crank arms are mounted one each to each side of the 
axle. The axle is carried within the bottom bracket housing or mount on a 
set of bearings which may be sealed bearings or ball bearings, which are 
commonly mounted with a cone inside, cup outside bearing. One side of the 
bottom bracket housing, usually the right, is threaded for the mounting of 
a correspondingly threaded fixed cup. The other side of the bottom bracket 
housing is threaded for the mounting of an appropriately threaded 
adjustable cup and lock ring. The right cup is installed, ball bearings 
and cone surfaces on the axle then permit a means for rotation of the 
cranks. The bottom bracket housing of prior art bicycles requires 
precision alignment of at least four tubes, the down tube, the seat tube, 
and two chain stays. In contrast, the bottom bracket housing of the 
present invention only requires two tubes. 
The seat mast tube and the down tube of the present invention are both 
selected from 11/2 OD aluminum tubing. The seat mast tube and the down 
tube are both provided at their lower ends with a saddle shape cut into 
the tube so that the ends of the tubes will conform to the cylindrical 
surface at the outside of the bottom bracket housing 5. The seat mast tube 
is aligned perpendicularly to both the longitudinal axis of the 
cylindrical bottom bracket housing, and to the cylindrical surface of the 
bottom bracket, and is centered on the housing so that the longitudinal 
axis of the tubular seat mast intersects the mid point of the longitudinal 
axis of bottom bracket housing. The seat mast tube is welded 360.degree. 
around the saddle of the intersection of the seat mast tube in the bottom 
housing to securing the bottom housing in the seat mast tube. The seat 
mast tube passes through opening 26 fashioned, formed or shaped in the 
channel web 12. 
In the specific embodiment illustrated the length of the mast tube and the 
bottom bracket assembly is 14 inches measured from the upper end of the 
seat mast tube 3 to the center of the axis of the cylindrical bottom 
bracket housing. In the illustrated embodiment the seat mast tube is 
welded to the web 12 at the upper surface 11 360.degree. around the seat 
mast tube in a fillet weld so that 9 inches of the seat mast tube projects 
perpendicularly upward from the upper surface 11 of the channel member, 
therefore the axis of the bottom bracket housing 5 is 5 inches below the 
upper surface of the channel member. This axis will also be 2 7/16 inches 
above the wheel base line measured from the axis of the front wheel to the 
axis of the rear wheel when the remainder of the frame is configured as 
will be further described below, and as previously discussed. Since both 
the head tube and seat mast tube are oriented perpendicularly to the upper 
surface of the channel member, the specific embodiment of the present 
invention herein described utilizes a head tube angle of 71.degree. and 30 
minutes measured to the horizontal (defined by a line running from the 
axis of the front wheel to the axis of the rear wheel which are of equal 
diameters in the instant case), therefore the angle of the seat mast tube 
to the horizontal just defined is also 71.degree. and 30 minutes. 
After the seat mast tube is welded into position the down tube is fitted 
through opening 27 in the upper surface of the web so that the channel 
section cut at the bottom of the down tube 4 nests against the cylindrical 
outer surface of the bottom bracket shell 5. The down tube saddle is 
shaped so that adjacent portions of the lower part of the seat mast tube, 
and the lower part of the down tube meet, or nearly meet, where they are 
both connected to the bottom bracket shell or housing. The longitudinal 
axis of the down tube, and the longitudinal axis of the seat mast tube 
intersect at a point below the longitudinal axis of the bottom bracket 
housing. In the specific embodiment illustrated the angle between the down 
tube axis and the bottom tube axis is 63.degree.. The down tube is welded 
to the bottom bracket housing all 360.degree. around the tube where the 
saddle cut into the lower portion of the down tube meets the outer 
cylindrical surface of the bottom bracket. 
The down tube is then welded all 360.degree. around the tube where the tube 
passes through the web of the channel frame member at the upper surface 11 
of the channel frame member, and optionally at the lower surface 15 of the 
channel frame member. 
A saddle cut is also made at the upper portion of the down tube 3 where it 
fits against the outer cylindrical surface of the upper portion of the 
head tube 2. When the frame is configured for the specific embodiment 
herein described there will be a 1/2 in. clearance measured from the top 
of the head tube 2 to the upper most point of the intersection of the down 
tube and head tube. The down tube is welded in place all 360.degree. 
around the tube where the head tube saddle intersects and conforms to the 
upper portion of the head tube. The longitudinal axis of the down tube 
intersects with the longitudinal axis of the head tube, and the angle 
measured therebetween is 67.degree.. 
Referring now to FIGS. 1, 7 and 8 there is illustrated an alternative 
embodiment of the present invention which can further be provided with two 
diagonal bracing members 6. In the illustrated embodiment these 
longitudinal diagonal bracing members comprise 5/8 in OD aluminum tubes, 
each affixed by welding at an upper end to a point located near the upper 
end of the seat mast tube 3, and each diagonal brace 6 welded at its lower 
end to a point on the upper surface of the channel frame member between 
the rear of the channel frame member and the intersection of the channel 
frame member and the seat mast tube. 
Although these optional diagonal support members 6 are illustrated in FIG. 
8 as simple rigid tubes, they could be fashioned as telescoping tubes 30 
provided with suspension means, such as a coil spring 31 either carried 
within the telescoping tubes 30 mounted to the exterior Of the telescoping 
tubes. See FIGS. 8a, 8b, and 8c. They can further be provided with 
hydraulic suspension means 32 either alone or in combination with the 
spring suspension means, for instance as used on motorcycles. For such an 
embodiment of the present invention provided with suspension means the 
channel frame disclosed herein could be further modified by sectioning the 
frame and providing a hinge 33 between sections, for instance as indicated 
in FIG. 8a by hinge location 28 and in FIGS. 8b and 8c as hinge 33 29 of 
FIG. 8 indicate portions of the channel frame which could be further cut 
away for an embodiment provided with such a hinged section frame and 
suspension means as in FIGS. 8b and 8c. Cutting away this section would 
further reduce the weight and compensate for some of the weight added in 
the suspension components. 
The cut out or notch 17 provided for the rear wheel in the specific 
embodiments illustrated provides an opening 21/2 inches across. This is 
ample clearance of the wider tires, such as are used on BMX and free style 
type machines. A racing frame would not need such a clearance, and the 
width of the whole frame could consequently be narrowed. Since the channel 
frame member also provides a protective guard over the upper portion of 
the chain sprocket mounted to the cranks, which are connected to an axle 
rotatably mounted in the bottom bracket housing, and also provides a guard 
for the upper part of the driving chain, a limiting factor on narrowing 
the interior clear width of the channel frame member measured from leg 13 
to leg 14 would be the clearance needed for the types of gearing mounted 
to the bicycle. 
The chain guard and partially enclosed drive train featured in the present 
invention is especially desirable in certain types of off-road cycle-cross 
or mountain type riding, and the partial enclosure or housing provides 
protection to the enclosed drive train components from under brush, tree 
stumps, sticks, limbs and the like. In a recreational commuter bicycle 
embodiment, the covering of the chain rings, the drive chain, and the rear 
sprockets's will keep clothing such as pants cuffs from being caught in 
any of these components. 
The channel frame design of the present invention also provides ready 
mounting locations which facilitate the mounting of all types of bicycle 
equipment and accessories, such as derailleurs, two examples of which are 
indicated in FIGS. 6 and 12, and FIG. 8. Brake mount locations at the rear 
could be mounted either above or below the channel frame design, either at 
locations intermediate the seat mast post 3 and the wheel notch cut-out 
17, or to the diagonal support tubes 6 if the frame is provided with such 
supports, or to either the upper surface or sides of the channel frame 
member outboard of the wheel notch cut-out 17 in an appropriate location 
to act against the wheel rim. 
Although for the purposes of illustration specific embodiments of the 
present invention have been described, in particular referring to an 
aluminum alloy T6061 aluminum for both the tubes and the channel frame 
member, and having been described as welding said members together, the 
invention is not to be understood as limited thereto, or to the specific 
dimensions given for components. 
The described components and materials--namely T6061 aluminum have the 
advantages of low cost, availability, established welding techniques, 
corrosion resistance, good machinability, and the materials are not 
brittle. This invention could also be constructed from other materials 
listing by way of illustration and not limitation: steel or steel alloys 
such as Reynolds 531, Berrilum alloys, Titanium alloys, Magnesium alloys, 
or composites of other materials including materials such as glass fibers, 
carbon fibers, high strength plastic fibers, boron fibers, aluminum oxide 
fibers, silicon fibers and the like, or molded plastics. Although all the 
tubes described were straight gauge, the tubes could be so made as to have 
larger wall thicknesses at the connecting joints, particularly desirable 
for certain of the mentioned alloys or materials. In addition, depending 
upon the material and intended use of the frame, the frame could be heat 
treated after welding to restore essentially full strength at the welded 
or brazed connections since some of the listed materials tend to lose 
strength in the welding or brazing process. 
Although not fully shown in the illustrations, this invention further 
comprises the balance of the bicycle which is of conventional form, and 
which comprises a fork, head set, wheels, pedals, pedal cranks connecting 
the pedals to the crank axle, handle bars, brakes, and a drive chain 
drivingly connected between the crank axle and rear wheel, all of 
conventional form (also not shown). 
Although certain connecting techniques, such as welding, have been 
described with reference to a particular embodiment, aluminum components, 
it should be understood that the means of connection will be chosen to 
suit the materials used to construct the frame in accordance with the 
present invention, and that certain materials would best be connected by 
brazing, gluing, bonding or otherwise interconnecting materials, and thus 
the connection means would be chosen to suit the material. 
While a particular example of the present invention has been shown and 
described, it will be apparent to those of skill in the art that numerous 
changes and modifications can be made without departing from the 
invention. The purpose of the appended claims is to cover all such changes 
and modifications included within the spirit and scope of the invention. 
Therefore,