Motor vehicles – Special wheel base – Having only two wheels
Reexamination Certificate
2000-10-02
2003-01-14
DePumpo, Daniel G. (Department: 3611)
Motor vehicles
Special wheel base
Having only two wheels
C180S223000, C280S279000
Reexamination Certificate
active
06505699
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention as disclosed in the first and second embodiments relates to a two-wheel drive two-wheeled vehicle, and more particularly a two-wheel drive motorcycle having the rear wheel driven by the traditional chain or shaft mechanism and the front wheel driven by a series of shafts and gears transferring power to the front wheel from either the motorcycle transmission or the driven rear wheel. Moreover, as a novel and inventive improvement to all prior attempts at constructing two-wheel drive motorcycles and two-wheel drive bicycles including the embodiments disclosed in related applications, the two-wheel drive motorcycle disclosed herein is configured so that the front wheel drive components counterbalance all steering system torque reactions and moments of inertia through placement of numerous components located on the axis of steering and symmetrically within the motorcycle front fork. The novel configuration enable the rider to maintain control of the two-wheel drive motorcycle during the high-speed, high-power rotation of the engine-powered front wheel drive.
2. Description of the Related Art
As motorcycle and off-road motocross riding has gained broader appeal, the demands that riders place on their vehicles have increased dramatically. Conventional motorcycles are powered through a chain or shaft linking the engine to the rear wheel. However, motocross and motorcycle riders are now facing riding conditions and obstacles where having only rear wheel drive can lead to vehicle damage, loss of control and an unstable front wheel during cornering and off-road riding in general. For professional riders, precious race time is lost avoiding obstacles or losing traction in loose rocks, sand, dirt, mud, or ice. Traction and climbing ability are severely limited in extreme mountain conditions by only having the rear wheel provide power. Accordingly, there is a need in the industry for a two-wheel drive motorcycle that efficiently and safely transfers power from the motor through the transmission to the front wheel, that provides the rider with increased ability to safely negotiate rough terrain, and that does not detract from the aesthetic qualities, appearance or function of the motorcycle itself.
While both two-wheel drive motorcycles and two-wheel drive bicycles have been attempted in the past, the present invention relating to the two-wheel drive motorcycle offers significant technical and functional innovations previously not disclosed or anticipated. The present invention features symmetrically positioned and counterbalanced front wheel drive components relative to the axis of steering and motorcycle centerline that eliminate or minimize the torque reactions that would otherwise adversely affect motorcycle control when the front wheel is driven. Additionally, the present invention illustrates a front wheel drive for a two-wheel drive motorcycle that is completely enclosed within the motorcycle frame, head tube, and front fork in a way that reduces danger to the rider from moving parts and ensures that the motorcycle steering is unencumbered.
By comparison, previous attempts at constructing a two-wheel drive motorcycle have utilized hydraulic, hydrostatic, and variations of belt, shaft or chain drives that have numerous exposed parts. Importantly, none of the previous attempts at constructing a two-wheel drive motorcycle would result in a functional two-wheel drive motorcycle. Primarily, none of the prior attempts have taken into account that a motorcycle drive system based upon rigid shafts can spin at several thousand revolutions per minute producing torque reactions along the front fork from the spinning front wheel drive system that would result in an uncontrollable pull on the front wheel. Furthermore, previous attempts have failed to provide a motorcycle with a full rage of steering.
U.S. Pat. No. 4,702,340 shows a motorcycle with a front wheel driven by a chain supported by the motorcycle fork and handlebars powering a large chain drive gear on the front wheel. The patent is assigned to Rokon International who previously produced a similar two-wheeled vehicle capable of only low-speed rough terrain maneuvering. As shown, the front wheel drive chain would severely limit the ability to manufacture a motorcycle capable or any high speed maneuvering.
U.S. Pat. Nos. 5,014,808, 5,050,699, 5,054,572, and 5,113,964 show variations of motorcycles with a front wheel powered by a series of belts, chains, gears, or sprockets from the motor to the front fork and then to the front wheel along one side of the fork. While a motorcycle does not need the same broad range of steering that is necessary for a bicycle, the presence of a bulky drive chain on one side of the motorcycle would cause problems with both steering as well as unwanted torque reactions that would make the motorcycle potentially uncontrollable at high speeds. The exposed front wheel drive chains also pose a potential hazard to the rider.
U.S. Pat. Nos. 5,873,428 and 5,894,903, JP9156570A2, EP 0 779 205 A2, and EP 0 779 205 A3 show motorcycles with a front wheel driven by hydraulic motors or hydrostatic pressure from the engine to the front wheel. A motorcycle with a front wheel driven by a hydraulic drive system would have significantly less efficient power transfer than a rigid-shaft drive system.
GB Patent Number 1,284,821 shows a motorcycle with a front wheel driven by an extremely complex shaft and gear drive system. The motorcycle includes a radically-redesigned front end without a head tube, very large gears extending well in front of the axis of steering, and a front drive system located within one fork leg. The adverse torque reactions resulting from the unbalanced front wheel drive system and high-speed rotation of the front wheel drive would likely result in a motorcycle that is uncontrollable. This configuration of the front wheel drive would also prevent a full range of steering.
WO 93/09992 (PCT/FR92/01084) discloses a front wheel drive for a two-wheel drive motorcycle that is not counterbalanced on the axis of steering and is located in a significantly enlarged front end lacking a head tube. Such a front end would interfere with the full steering range of the motorcycle during sharp turns and make the motorcycle impossible to ride on complex terrain and potentially pose a safety risk. Additionally, while the invention discloses a drive system within both fork legs, the invention fails to disclose a counter-balanced drive system as several gears are vertically offset from each other. Further, as illustrated, the dimensions of a standard motorcycle would require that the drive gears be several inches in diameter and both the shafts and gears are inadequately supported for the enormous torque that would be transferred through such a drive system design. In short, the disclosed two wheel drive vehicle fails to adequately address the problem of torque counter balancing or provide a full range of steering.
The attempts at constructing two-wheel drive two-wheeled vehicles also include several two-wheel drive bicycle designs. Generally, two-wheel drive bicycles fall into two categories: 1) permanent designs involving drive trains attached to the frame, and 2) retrofit kits which convert existing bicycles to two-wheel drive. The main drawbacks to these systems are: 1) a modification to the standard bicycle in the form of a kit is expensive when considered as an addition to a bicycle purchase, 2) the low strength flexible shaft limits the allowable loading on the system, 3) the retro-fit kit requires considerable skill to attach and cannot be designed to optimally work with every frame design, and 4) the drive mechanisms are often large and openly exposed on the outside of the frame potentially creating additional hazards for the rider and detracting from the overall appearance of the bicycle. In short, none of the two-wheel drive bicycles discussed below could be successfully modified or adapted to produce a functional two-wheel drive motorcycle.
Allora Louis J.
Christini Steven J.
Dunn Michael J.
Pigeon Robert L.
Shook Jeremy T.
Christini Technologies, Inc.
Cooley & Godward LLP
DePumpo Daniel G.
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