Patent Application
20100259026
This invention relates to motorcycles. More particularly, this invention relates to a motorcycle frame having torsion shock absorbers from which cantilevered wheels can be mounted and from which shock absorbing movement of one part of the frame relative to another part of the frame occurs.
Motorcycles have been in use for more than 100 years. Typically, a motorcycle frame suspends the steerable wheel in front of the frame through the use of a fork that retains the wheel between two arms. For shock absorption, the arms of the fork traditionally have incorporated compressible hydraulic shocks inline with the arms. However, traditional forks suffer significant shortcomings. When a brake is applied to the front wheel on a motorcycle, the shocks compress and the front end of the motorcycle dives, causing an unsafe condition for the rider. There is a binding effect because of the torque experienced on the fork when the brake is applied, and, over time, this binding effect creates leaks in the hydraulic seals of the shock absorbers. Hydaulic fluid can subsequently contaminate the brake pads, thus reducing braking efficiency, and again causing an unsafe condition for the rider. Because traditional hydraulic shock absorbers generate heat as the result of telescopic stiction in their normal operation, this also contributes to leaks and eventual failure of the shock absorbers.
Torsion acting shock absorbers are known. In Henschen U.S. Pat. Nos. 5,277,450 and 5,411,287, there is disclosed a torsion axle for use as a shock absorber with trailers. Specifically, square sectioned torsion shafts, square sectioned metal tubes and a plurality of resilient rubber rods acting between the square sectioned torsion shafts and metal tubes are utilized. The resilient rubber rods are confined between the square sectioned metal tubes and the square sectioned metal shafts so as to be compressed by the square sectioned metal shaft when the square sectioned metal shaft rotates relatively to the square sectioned metal tubes. The resilient rubber rods come under compression and torsionally resist rotation of the square sectioned shafts. In a typical application, the metal tubes are attached to the trailer. The torsion shafts are attached to the wheels by an eccentric crank, which eccentric crank is off center with respect to a line extending vertically from the axis of rotation of the wheel vertically upward normal to the trailer. The crank extends outwardly and away from the metal tubes so that the wheels are supported outwardly and away from both the torsion axle and the trailer. When the trailer encounters shock inducing bumps along its path of travel, shock absorbing movement of the crank mounted wheel occurs.
Another problem experienced with traditional motorcycle designs is a result of having a forked arm on each side of the front wheel. In motorcycle designs having a combustion engine, the engine generates significant amounts of heat and incorporates a cooling system, either by air or by fluid. In either case, the flow of air is obstructed by the forked arms onto either the engine itself in air-cooled designs or a front-mounted radiator in fluid-cooled designs. Similarly, the presence of two forked arms also creates aerodynamic drag on the motorcycle.
Finally, removal of the front wheel is complicated by the presence of dual forked arms, and in many designs the wheel is secured independently to each forked arm, thus adding to the weight of the motorcycle as well as the time required to change out a wheel.
Thus, there is a heart-felt need for an improved motorcycle that has better braking and handling characteristics, lighter weight, and simplified shock absorption and suspension.
The present invention solves the problems described above by providing a motorcycle having a frame, a seat and at least one cantilevered wheel support, the cantilevered wheel support including a torsion acting shock absorber and providing connection to the frame. The cantilevered wheel support is attached to the steerable front wheel, or the rear drive wheel. The cantilevered wheel support includes an upper member and a lower member. The upper member and lower member are attached to a torsion acting shock absorber disposed between the upper member and lower member. In an embodiment, the upper member includes a fluid reservoir capable of storing coolant, fuel, or lubricant.
The cantilevered wheel support, when attached to the steerable front wheel, provides improved handling and braking characteristics as it resists diving of the front end of the motorcycle during braking, as torque from the front wheel works against force that otherwise would drive down the front end of the motorcycle. The cantilevered wheel support also improves safety and dynamic stability of a motorcycle by preventing shortening the wheelbase that would otherwise occur in traditional designs that incorporate telescoping shocks in the front wheel suspension. As front end dive is greatly reduced or eliminated, the wheelbase of the motorcycle is preserved.
In an embodiment, the motor is connected to the rear wheel by a roller chain or a belt, and the motor is mounted on a cantilevered wheel support extending from the torsion-acting shock absorber and tension of the chain or belt between the motor and rear wheel at a constant tension as the cantilevered wheel support moves. By maintaining a constant tension, wear on the roller chain or drive belt is greatly reduced.
In an embodiment, the frame includes a subframe extending from the frame and supporting the seat, and a torsion-acting shock absorber is disposed between the frame and the subframe to provide shock absorption to the seat, thus protecting the rider from shock.
The present invention reduces cost of manufacturing by having a simplified design, reduces friction-generated heat experienced in conventional forks, improves airflow over the motor, and reduces aerodynamic drag by using a singular wheel support for each wheel instead of a dual-support design. Similarly, as suspended weight is significantly reduced, the present invention provides improved handling over uneven terrain.
Many other features and advantages of the present invention will be realized from reading the following detailed description, when considered in conjunction with the drawings, in which:
Referring to
Having set forth the main structural elements of the present invention in
The present invention, as the result of changed geometry of front wheel 113, is, in an embodiment, outfitted with a radio-controlled braking system wherein there is no cable from the handlebars down to steerable front wheel 113. This allows bar spins to be performed, where a rider spins handlebars 106 to rotate steerable front wheel about the axis defined by gooseneck 104. Furthermore, in another embodiment that allows bar spins, a conventional cable-based braking system is utilized, with the cable passing through lower member 112, first torsion shock absorber 114, upper member 110, gooseneck 104 before connecting to a handbrake on handlebars 106. In an embodiment, a stop is welded to outside of frame 102 to prevent front steerable wheel 113 to be spun in the manner described above.
In an embodiment, lower member 112 and/or trailing arm 120 incorporates a reservoir tank that may used to store fuel, lubricant, or coolant. Lower member 112 and/or trailing arm 120 may also incorporate a battery that can be used to power various accessories on motorcycle 100 or serve as an auxiliary power source in other applications.
Torsion shock absorbers 114, 122 contribute greatly to the handling improvement and weight reduction of motorcycle 100. Directing attention to
Shock absorbers of the type illustrated in
