CLAIMS:
1. A bicycle comprising: a frame having a radius of curvature; a rear wheel attached adjacent to a rear end of the frame; a front fork pivotably attached adjacent to a front end of the frame, with the front fork having a radius of curvature substantially the same as the radius of curvature of the frame; and a front wheel attached to the front fork.
2. The bicycle of claim 1 with the frame comprising a hollow thin wall tube. 3. The bicycle of claim 2 with the frame having a round, oval or elliptical cross section.
4. The bicycle of claim 1 with the frame subsuming an arc of 120-180 degrees.
5. The bicycle of claim 2 further comprising a drive line component within the frame, with the drive line component including one or more of a battery, a motor controller, and an electric motor.
6. The bicycle of claim 2 further comprising a drive line component within the frame, with the drive line component including one or more of a fuel tank and an internal combustion engine. 7. The bicycle of claim 1 wherein the radius of curvature of the frame is constant.
8. The bicycle of claim 1 with the frame having a rear fork, and with the rear wheel supported only by the rear fork.
9. The bicycle of claim 1 further comprising a seat moveable along a top surface on a curved line constantly parallel to the radius of curvature of the frame.
10. The bicycle of claim 3 with the frame having an outside diameter ranging from 7-20 cm. 11. The bicycle of claim 1 further comprising a seat tube attached to the frame and extending generally radially inwardly relative to the frame, and with a chain ring, crank and pedals supported adjacent to a lower end of the seat tube, and with a chain connecting the chain ring to a sprocket on the rear wheel.
12. The bicycle of claim 11 with the seat tube attached to the frame in a cantilever design.
13. The bicycle of claim 1 wherein the frame forms a substantially semicircular shape extending from a front axle of the front wheel to a rear axle of the rear wheel.
14. The bicycle of claim 1 wherein the frame has no chain stays and no down tube as in a convention bicycle frame.
15. The bicycle of claim 1 further comprising a handle bar attached to a handle bar stem, with the handle bar stem extending downward through a clearance opening near the front of the frame, and connecting to the front fork.
16. The bicycle of claim 11 further comprising chain stays on either side of the rear wheel and connecting the lower end of the seat tube to the rear end of the frame, adjacent to the rear wheel axle.
17. A two wheel vehicle comprising: a rear wheel on rear axle; a front wheel on a front axle attached to a front fork; a frame, with the front fork attached to the frame at a pivot joint; the frame including an elongated hollow tube formed as an arc extending from the rear axle to the pivot joint. 18. The vehicle of claim 16 with the hollow tube formed as an arc having a substantially constant radius of curvature between the rear axle and the pivot joint.
19. The vehicle of claim 16 with the front fork also formed in an arc extending from the pivot joint to the front axle and having a radius of curvature substantially the same as the frame.
20. The vehicle of claim 17 with the rear end of the frame split into left and right side seat stays joined to left and right side chain stays, respectively, adjacent to the rear axle, and with the rear wheel between the left and right side seat and chain stays. |
TWO WHEEL VEHICLES
PRIORITY CLAIM
[0001] This Application claims priority to U.S. Provisional Patent Application Numbers 60/838,781 filed August 18, 2006 and 60/874,092 filed December 1 1 , 2006, both incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The field of the invention is two wheel vehicles, including conventional human-powered pedal bicycles, as well as two wheel vehicles having fuel or electrically powered engines or motors, such as mopeds, motorcycles and scooters.
BACKGROUND OF THE INVENTION [0003] Pedal powered bicycles have been in use for over 100 years.
During this time, the so-called double diamond bicycle frame has been the commonly used. This bicycle frame is typically manufactured by welding metal tubes or sections together. The diamond frame consists of two triangles, a main triangle and a paired rear triangle. The main triangle consists of the head tube, top tube, down tube and seat tube. The rear triangle consists of the seat tube, and paired chain stays and seat stays. The head tube contains the headset which supports the front fork. The invention contemplates a completely different and aesthetic bicycle frame design.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] In the drawings, the same reference number indicates the same
element in each of the views.
[0005] Fig. 1 is a side view of bicycle frame of a first embodiment of the invention.
[0006] Fig. 2 is a side view of a second embodiment. [0007] Fig. 3 is a top view of the front fork and/or rear fork of the frame shown in Figs. 1 or 2.
DETAILED DESCRIPTION OF THE DRAWINGS [0008] Fig. 1 shows a bicycle 10 having an arc frame 12. The arc frame 12 is typically formed from a thin wall hollow tube or extrusion. The arc frame 12 generally has smoothly curving cross section, such as a round, elliptical, or oval cross section. However, in alternative designs, other shapes may also be used, such as square, hexagonal, octagonal, or other polygonal shape. The frame 12 is preferably, but not necessarily symmetrical from side to side and top to bottom. The arch frame 12 has a radius of curvature R which may vary with the size of the intended rider, or the style of the bicycle. For example, R may range from about 50-80 or 60-70 cm. The radius R may also vary in designs where the frame is a segment of an ellipse or oval, rather than a segment of a circle. The frame 12 subsumes an arc of about 120-180 or 130-150 degrees, including the front fork. In Fig. 1 for example, the front and rear axles are at the same level, and the frame, together with the front fork, subsume an angle of about 180 degrees (a semi-circle). The diameter (or largest principal internal dimension for a polygonal shape) ranges from about 7 to 20 cm. In the example shown in Fig. 1 , the arc is about 140 degrees, with a 66 cm radius (to the centerline) of a round aluminum tube 10 cm outside diameter and 1.6 mm wall thickness.
[0009] As shown in Fig. 1 , the front fork 20 is attached to the frame 12 via a pivot joint 22. A handle bar 18 may connect to the front fork 20 through a clearance opening at the front of the frame 12. In the design shown in Fig. 2, a front fork turret 80 surrounds the clearance opening. Conventional bicycle or moped components such as a seat 13, front and rear wheels 24 and 34, front and rear axles 26 and 36, brakes, gears, etc. may then be attached to the frame and/or the front fork. In the design in Fig. 1 , a seat tube 14 is connected in a cantilever design adjacent to a center location of the frame 12. A chain ring 64, crank 62 and pedals 60 then drive a chain 66 extending around a rear sprocket 68 to propel the bicycle. Referring to Fig. 3, the front fork has left and right sides 28 and 30 with the front wheel 24 positioned between them. The back end of the frame 12 is similarly split to accommodate the rear wheel 34 generally on a centerline of the frame 12, between left and right side seat stays, having the same form as the front fork, and designated as 70 and 72 in Fig. 1. The bicycle in Fig. 2 also includes a front shock absorber 102 and rear axle slots 90 for adjustment of the rear axle position.
[0010] Referring still to Fig. 1 , since the frame 12 is hollow, and has sufficient internal space, certain optional components may be installed inside of the frame. For example, an electric motor 44 and/or an internal combustion engine 46 may be located within the frame 12. If used they can be linked to a sprocket on the rear wheel via a belt or chain extending inside or outside of the frame. Related components such as a battery or a controller 42, or a fuel tank 40 may also be located inside of the frame. One or more access doors 48 may be provided on the frame, to access storage compartments formed
within the frame, or to access internal components, such as a motor 44. If used, a motor 44 or 46 may optionally be located elsewhere on the frame 12, such as on the seat tube, with related components such as a controller, battery, fuel tank, etc. located within the frame and connected to the motor via electrical cables and/or fluid lines. Fig. 2 shows an alternative design further including chain stays 50, and a motor 44 or 46 supported on the chain stays 50 and/or the seat tube 14. The frame 12 may also be made of composite materials or plastics materials instead of metal. While a smoothly curving arc provides a unique appearance to the frame, the frame may optionally be made of a large number of tubular segments joined together, as with a polygon having a large number of sides.
[0011] When the frame 12 is used as a bicycle, the seat may be movable along the frame, and the pedals may be movable on the seat tube, to adjust for riders of varying height. These adjustments may be made repeatedly by the rider, or they may be selected and set at the factory during manufacture of the bicycle.