GB2409843A

GB2409843A - Gyroscopically-stabalised bicycle

Info

Publication number: GB2409843A
Application number: GB0400137A
Authority: GB
Inventors: John Surtees Wykeham Bradford
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-01-06
Filing date: 2004-01-06
Publication date: 2005-07-13
Also published as: GB0400137D0

Abstract

A bicycle with flywheel-discs mounted on the hubs of the roadwheels, in the space between the spokes, mounted on freewheel bearings, which flywheel-discs are of sufficient mass and of appropriate design to produce a significant gyroscopic effect when they rotate, this rotation being effected by the forward rotation of the roadwheels, the torque of the roadwheel hubs being translated to the hubs of the gyroscopic flywheels via freewheel-bearings, which freewheel-bearings allows the gyroscopic flywheels to continue to spin at the maximum angular speed achieved during powered progress, even after the deceleration or cessation of rotation of the roadwheels.

Description

1 2409843 Gyroscopically-stabilised bicycle This invention relates to a

gyroscopically-stabilised bicycle.

A bicycle-and-rider system is inherently unstable in a gravitational field, that is, in everyday use. 'Learning to ride a bicycle' is a skill in which the rider learns the art of balancing a system with a very high and massive centre of gravity by propelling it forward, and steering the bicycle so that the point of contact of the system with the ground is directly below the centre of gravity of the system, and at the same time shifting their body mass fractionally and constantly to maintain the centre of gravity of the system directly above the point of contact with the ground.

The dynamics of the stability of a bicycle-and-rider in movement as I have described are, however, extensively modified by the fact that the road wheels of the bicycle rotating about their hubs behave like two gyroscopes. Without going deeply into the physics involved, it may be sufficient to say that these two gyroscopes greatly aid the stability of the bicycle in motion for two reasons: 1 - as gyroscopes they tend to maintain a constant orientation in space, in this case, upright, and 2 - a peculiarity of a gyroscope is that a force applied in a particular direction to its axis of rotation is translated to movement in another direction.

The stabilising effect of the spinning road-wheels of a bicycle can be demonstrated by running a bicycle on a "rolling road" of the kind used in a motor-vehicle testing-station to measure the effectiveness of a vehicle's brakes: when the wheels of the bicycle are being rotated, it is easy to balance the bicycle upright without putting one's feet to the ground, even though the bicycle itself is not moving forwards. The strength of the gyroscopic effect is proportional to the angular momentum of a gyroscope, that is, to the mass of the gyroscope flywheel, its diameter, and its speed of rotation. So, the faster a bicycle is moving forward in the ordinary road-situation, the easier it is to balance, because the road wheels are acting as gyroscope flywheels, and their effectiveness at maintaining a constant orientation in space, given that the mass and the distribution of that mass throughout the flywheel are both constant, is proportional to their angular velocity, the speed of their rotation.

In the ordinary road-use of a bicycle, much of its use in towns is involved with manoeuvring with other vehicles and at junctions at low speeds, where the gyroscopic effect of the wheels is at a minimum, making the bicycle difficult to handle and necessitating much repeated change-ofline in order to maintain the points of contact with the road perpendicularly below the centre-of-mass of the bicycle-and-rider system, that is by maintaining an irregular "wavy" line of travel. Manoeuvres such as passing between two cars at very low speeds may be difficult or impossible. Many manoeuvres at junctions and the like cannot be executed without the feet of the cyclist being frequently put to the ground. Safety may be compromised by the cyclist "wobbling" and "weaving" through traffic, around obstacles, and when negotiating junctions, this "wobbling" being a necessary way of maintaining stability when this stability is not being assisted by the gyroscopic effect of spinning wheels.

In this invention an otherwise standard bicycle has road-wheels within which are mounted flywheels that add to the gyroscopic effect of the roadwheels and are mounted on the same hub. In addition, these gyroscopic flywheels are mounted on freewheel-bearings such that the forward motion of the bicycle accelerates the flywheels, but when the bicycle slows down or stops, the flywheels continue to spin, giving the bicycle much of the stability it would have at a higher speed.

A specific embodiment of the invention is here described by way of example with reference to the accompanying drawings in which: Figure 1 shows a side elevation of the bicycle (certain details like brakes, gears, chain, valves, set-screws, lights, wheel-spokes and bell having been omitted for clarity) showing gyroscopic flywheels mounted on the wheel hubs between the wheel spokes, marked with line of section through front wheel M. Figure 2 shows cross-section M through the bicycle wheel showing the gyroscopic flywheel mounted on a freewheel-bearing on the wheel hub.

Figure 3 shows a typical low-friction ratchet-and-paw! freewheel bearing, although this particular design of freewheel is not a necessary part of the invention, which covers a flywheel mounted on a freewheel bearing of any kind mounted on the wheel hub.

Referring to the drawings the bicycle consists of a standard bicycle with conventional spoked wheels with a flywheel being mounted on the axle of each roadwheel in the void between the spokes supported by freewheelbearings such that the flywheel will be maintained at the same speed as the road-wheel when the road-wheel is accelerating or rotating at a uniform speed, but will continue to spin when the road-wheel decelerates, rotates at a lower speed, or is stationary. The principle embodied in this invention covers other two-wheeled vehicles, including motor- bicycles and children's bicycles.

Claims

1 A gyroscopically-stabilised bicycle comprising a standard bicycle with front and rear roadwheels each having a disc mounted concentrically on the wheel hub, which discs, being mounted on freewheel hubs, are impelled to rotate in a forward direction by the bicycle roadwheels when these roadwheels rotate forwards, and continue to rotate when the roadwheels decelerate or stop, each disc being of a material and shape to produce a gyroscopic effect when in rotation.

2 A gyroscopically-stabilised bicycl.= as claimed in Claim 1 having gyroscopically- acting discs mounted on the roadwheel hubs rotating in the space between the spokes.

3 A gyroscopically-stabilised bicycle substantially as described herein with reference to Figures 1 - 3.