GB2307888A

GB2307888A - Bicycle with low centre of gravity

Info

Publication number: GB2307888A
Application number: GB9525058A
Authority: GB
Inventors: Russell John Searle
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-12-07
Filing date: 1995-12-07
Publication date: 1997-06-11
Also published as: GB9525058D0

Abstract

A bicycle has a relaxed riding position in which the excursion of the pedals extends forwards of the steering hand grips B, allowing a lower and safer seat position consistent with the legs being fully extended. The feet in their forward position overlap the diameter of the front wheel, the steering inclination being such to reduce the sideways excursion of the front wheel. To allow a relaxed steering position for the arms, the steering members pass to the side of the legs when the steering is turned. As the pedaling torque reaction has a greater horizontal component than the conventional bicycle, a thrust supporting belt is also proposed (fig.4) which disengages when the rider dismounts. Means are also proposed by which the bicycle may be folded wherein the steering members pass to each side of the rear wheel. Handlebar grips B may be ovoid or spherical in shape. The bicycle may have awaiting electric propulsion.

Description

IMPROVEMENTS IN PEDAL CYCLES The riding position on the conventional bicycle is determined largely by the need to accommodate the rider behind a steering system in which the front wheel and handlebars, in all positions, are clear of the rider's feet and legs, within the historically determined parameters of wheel size, steering angle and wheeibase.

To limit the space occupied, the rider must therefore adopt the equivalent of a forwardly inclined standing position in which the saddle must be sufficiently high for the legs to be outstretched with the feet on the pedals.

Such a position is however unstable and uncomfortable when stationary and the rider is vulnerable to head injury in case of collision and the forward position of the trunk produces fatigue of the arm and neck muscles.

The object of the present invention is to provide a lower, safer and more comfortable riding and stationary position with the legs well forward, similar to sitting in a chair, which is more suitable for present day road and traffic conditions.

To achieve this without an excessively long wheelbase the riders feet in their forward position overlap the front wheel; however, the combination of a shallow steering axis angle with a high degree of offset from the wheel centre makes the effective radius through which the rear of the front wheel turns sufficiently small to allow an adequate turning circle without the wheel coming into contact with the rider's feet.

Features of the invention are the disposition and configuration of the steering system which uses twin diverging steering members and a method of adjusting the seat by means of radius arms.

The invention also describes a simple method of folding the bicycle in which the twin steering members pass to each side of the rear wheel.

The twin diverging members which are normally in front of the rider's legs are spaced sufficiently to pass to the outer sides of the legs when the steering is turned, the absence of any horizontal parts, preventing any abutment with the rider's legs.

In a practical embodiment of the invention shown in Fig.1 the steering assembly consists of forked members A carrying the front wheel which diverge upwards to form the steering members and terminate at the handgrips B which project forward at an angle between 45" and the vertical. Alternatively the handgrips may be spherical or ovoidal as shown in Fig la.

The frame member C is articulated along its length about the steering axis X, inclined at around 600 to the horizontal, by means of two ball joints which are adjustable longitudinally one to change the inclination of the steering axis, the other to change the castor angle. The ball joints being arranged as shown in Fig. 2.

The frame member C joins the steering assembly to the pedal crank bearing D and a triangulated frame carrying the rear wheel and saddle may be pivoted to the frame member C about an axis coinciding with or adjacent to the pedal crank axis to enable the bicycle to be folded in which case the steering members and the hand-grips pass to each side of the rear wheel.

The triangulated frame consists of the horizontal members E which extend from the pedal crank axle to the rear wheel and the substantially vertical members F which extend from the rear wheel to the saddle. The members F are intersected by the inclined members G which continue rearwards to form a luggage rack. The members F are adjustable in an arc about the rear wheel centre, as shown, to alternative positions along the members G providing adjustment of the position of the seat relative to the pedals.

The position of the pedal crank axle relative to the steering axis is such that in their forward excursion the rider's feet overlap the front wheel as shown in Fig 3. However, the effective radius the rear of the wheel turns about the steering axis, is around 50% of the radius of the wheel, and such that it allows a total excursion of not less than 300 for steering.

To absorb pedal thrust reaction, a belt or cord which is attached to the peak of the saddle as shown in Fig 4, is adapted to pass between the legs of the rider and around his back at waist level. The belt disengages from the saddle when the rider moves forward in dismounting, the belt may terminate in a ring which engages with the peak of the saddle or with an engaging member fixed relative to it.

Claims

Having described the invention, what I claim is as follows:

Claim 1: A bicycle having a pedal crank axle positioned between the diameters of the wheels such that the path of the rider's feet overlaps the front wheel. And a steering axis inclined to the horizontal and offset from the wheel centre so as to allow a total steering movement at least 300.
Claim 2. A bicycle according to claim one wherein the saddle is to the rear of the rearward excursion of the pedals.
Claim 3. A bicycle according to claims one and two wherein the steering hand-grips are to the rear of the forward excursion of the feet.
Claim 4. A bicycle according to any previous claim wherein the steering members diverge upwardly from the vicinity of the tyre and pass to the outer sides of the legs when the steering is turned.
Claim 5. A bicycie according to claim four wherein the steering members continue downwards to form the front wheel forks.
Claim 6. A bicycle according to claim four or five in which handlebar grips forming continuations of the steering members project upwards at an angle between the vertical and forwards at 450 Claim
7. A bicycle according to claim four and five in which the handlebar grips are ovoidal or spherical in shape being characterised by having a three dimensional gripping surface.
Claim 8. A bicycle according to any previous claim wherein a radius member supporting the saddle is intersected by a fixed frame member along which the radius member is attached to provide alternative positions for the saddle.
Claim 9. A bicycle according to claim eight wherein a frame member extends from a point between the steering axis and the pedal crank to a point between the saddle and the rear wheel and continues rearwards to form a luggage carrier.
Claim 10. A bicycle according to any previous claim wherein a frame member which is articulated along its length about an inclined steering axis connects the rear frame portion to the steering and front wheel assembly.
Claim 11. A bicycle according to claim ten wherein the articulation is by means of two ball joints which are relatively adjustable to vary the angle of the steering axis or the castor angle of the front wheel.
Claim 12. A bicycle, according to any previous claim, having auxiliary electric propulsion

Claim 12. A bicycle according to any previous claim in which a flexible pedal thrust reacting member is attached to the saddle by means of a device which is disengaged by relative forward movement of the rider, the member being adapted to pass between the legs of the rider and around his back at waist level.

Claim
13. A bicycle according to claim twelve wherein the thrust reacting member consists of a single piece of flexible webbing or cord formed into two loops passing around the body and the saddle respectively.

Claim
14. A bicycle according to any previous claim wherein a rear frame portion is pivotable about a transverse axis to a frame portion carrying the steering and front wheel assembly such that when folded the steering members pass to either side of the rear wheel.

Claim
15. A bicycle, according to any previous claim, having auxiliary electric propulsion Amendments to the claims have been filed as follows Claim 1. A bicycle having a pedal crank axle positioned between the diameters of the front and rear wheel wherein two steering members diverge in an upward direction and pass to the outside of the riders legs when the steering is turned, the axes of articulation of the knee joints, during part of their excursion, intersecting the steering members.

Claim 2. A bicycle according to claim one in which handlebar grips forming contiuations of the steering members are set at an angle to the steering members of between

1500 and 60".

Claim 3. A bicycle according to claim one and two wherein the steering members continue downwards to form the front wheel forks.

Claim 4. A bicycle according to claim one and two in which the handlebar grips are ovoidal or spherical in shape being characterised by having a three dimensional gripping surface.

Claim 5. A bicycle according to any previous claim wherein a radius member supporting the saddle is intersected by a fixed frame member along which the radius member is attached to provide alternative positions for the saddle.

Claim 6. A bicycle according to claim five wherein a frame member extends from a point between the steering axis and the pedal crank to a point between the saddle and the rear wheel and continues rearwards to form a luggage carrier.

Claim 7. A bicycle according to any previous claim wherein a frame member which is articulated along its length about an inclined steering axis connects the rear frame portion to the steering and front wheel assembly.

Claim 8. A bicycle according to claim seven wherein the articulation is by means of two ball joints which are relatively adjustable to vary the angle of the steering axis or the castor angle of the front wheel.

Claim 9. A bicycle according to any previous claim in which a flexible pedal thrust reacting member is attached to the saddle by means of a device which is disengaged by relative forward movement of the rider, the member being adapted to pass between the legs of the rider and around his back at waist level.

Claim 10. A bicycle according to claim nine wherein the thrust reacting member consists of a single piece of flexible webbing or cord formed into two loops passing around the body and the saddle respectively.

Claim 11. A bicycle according to any previous claim wherein a rear frame portion is pivotable about a transverse axis to a frame portion carrying the steering and front wheel assembly such that when folded the steering members pass to either side of the rear wheel.