System for providing gyroscopic stabilization to a two-wheeled vehicle
This invention provides a stabilizing system and method for two-wheeled vehicles (typically small, human-powered bicycles) that affords the rider no restriction on the full range of movements (banks, leans, etc.) common to bicycles, but that provides greater stability during turns and other maneuvers so that an unintentional bank or tilt (potentially causing a fall) is less likely, even at relatively slow speeds and startup. A rotating mass of predetermined mass-value and radial mass-distribution is provided coaxially with the front axle. The mass is supported on bearings so as to freewheel with respect to the rotation of the front wheel. As such it can be induced to spin significantly faster than the front wheel thereby generating a gyroscopic effect at the front wheel about the axle. This gyroscopic effect influences the steering of the wheel by the rider. Due to precession, the wheel tends to follow any excessive bank by the bicycle, ensuring that the rider can “steer-out-of” an unintended tilt or bank. Likewise, the gyroscopic effect limits the rider's ability to execute excessive steering, thereby preventing jackknife movements.
1. A system for stabilizing a two-wheeled vehicle comprising:
a moving mass mounted with respect to a steerable front wheel of the vehicle that has a characteristic precession so that the front wheel is urged in a direction of an unintentional bank to provide recovery in the form of steering from the bank, the front wheel being mounted on a steerable front fork having an axle an inner hub coaxial with the axle that allows the front wheel to rotate relative to the axle and the front fork;
the moving mass being rotatably mounted on an outer hub that is coaxially mounted on the inner hub of the front wheel with a bearing structure therebetween so as to allow the moving mass to rotate freely with respect to the inner hub; and
a drive hub attached to the moving mass, constructed and arranged so that selectively engaging an interface of the drive hub with a selectively movable drive member causes spin-up of the moving mass to a rotating state from a nonrotating state with respect to the inner hub while the inner hub and the front wheel is stationary and non-rotating.
2. The system as set forth in claim 1 wherein the moving mass comprises a disk.
3. The system as set forth in claim 2 wherein the front wheel is a bicycle front wheel mounted on the steerable fork, the steerable fork being operatively connected to handlebars.
4. The system as set forth in claim 3 wherein the disk comprises a structure having mass concentrated adjacent to an outer perimeter thereof.
5. The system as set forth in claim 1 wherein the drive member comprises a pull cord that spins the drive hub by action of pulling and a recoil winding reel to draw the cord after pulling.
6. The system as set forth in claim 1 wherein the drive hub is constructed and arranged to engage an electrically operated tip that causes the drive hub to spin in response to engagement by and rotation of the tip.
7. The system as set forth in claim 1 wherein the front wheel includes a shield that restricts access to the mass.
8. The system as set forth in claim 7 wherein the shield includes a port through which the drive member is passed to engage the interface of the drive hub.
9. The system as set forth in claim 2 wherein the disk is characterized by an I value of between approximately 210 and 240 pounds* in 2 .
10. The system as set forth in claim 9 wherein the disk rotates at initial spin-up at a rotational velocity of between approximately 250-400 RPM.
11. The system as set forth in claim 2 wherein the disk rotates at initial spin-up at a rotational velocity of between approximately 250-400 RPM.
12. The system as set forth in claim 2 wherein the disk includes spokes interconnected between the outer hub and a mass at an outer perimeter of the disk.