AU723837B2

AU723837B2 - A frame and drive mechanism for bicycles and other machines

Info

Publication number: AU723837B2
Application number: AU52159/96A
Authority: AU
Inventors: Martin Paul Rudd
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-05-10
Filing date: 1996-05-09
Publication date: 2000-09-07
Anticipated expiration: 2016-05-09
Also published as: AU5215996A

Description

A F2Af-x A--t-b,1,s QY ~fA'No-- ortaR 1- M&leC-HI ~ket6e QSfE 'C L l -1- A FRAME AND DRIVE MECHANISM FOR BICYCLES AND OTHER

MACHINES.

The following statement is a full description of this invention, including the best method of performing it known to me.

This invention relates to improvements to the drive mechanism and frame required to support the rider, the two being mutually dependent, for bicycles and other machines.

It occurs to me that previous designs of the bicycle have problems in a number of areas. Firstly, is the inefficient in which the human powered natural reciprocating leg motion is converted to rotary motion. Secondly, the legs are 1 forced to move in a circular pedaling pattern when natural leg movement closer approximates a straight line. Thirdly, the stroke of the pedal crank, is not infinitely variable for individual riders, nor can it be varied to suit varying conditions whilst :riding. Fourth, the rider presents a large frontal area to the direction of motion resulting in a correspondingly large atmospheric drag co-efficient. Fifth, the body's centre of gravity is a long way from the ground, causing previous designs to be unstable. Sixth, the riders body is supported badly, the upper torso being supported by the arms only, resulting in the fatigue of the rider, the lower torso being supported uncomfortably and sometimes painfully by the seat. Seventh, :the position of the body being bent over and forming a 900 angle at the pelvis is not conducive to physical exertion but is conducive to lower back problems.

-2- The first objective of this invention is to provide a frame and drive mechanism applicable particularly to a bicycle, but usable also for other machines, whereby the frame supports the rider in a prone position, in alignment with the longitudinal axis of the bicycle, head facing forward, the torso supported at the chest and pelvis, the arms supported conventionally by the handlebars, and the legs supported on pedals. The pedals themselves are fixed to left and right pedal assemblies, one on each side of the bicycle, which are constrained to move linearly forward and rearward, synchronously, and in opposite directional sense to each other, parallel to each other and to the longitudinal axis of the bicycle. The pedal assemblies having fixed therein an upper and lower linear toothed rack in the right pedal assembly, and a lower linear toothed rack in the left pedal assembly which enmesh with and effect a rotation into toothed gears, mounted on two concentric shafts, their axis oriented horizontally and at right angles to the longitudinal axis of the bicycle, thereby converting linear motion to rotational motion. The two concentric S"shafts are comprised of an inner shaft, and an outer concentric shaft which, are constrained to always rotate synchronously, and in opposite rotational sense. The outer shaft is supported by the inner shaft, and extends over only a part of the inner shaft, enabling both the inner and outer shafts to be coupled 20 to an outer concentric cylindrical hub by uni-directional couplings (sometimes called a ratchet, one way bearing, needle clutch, one way clutch, or clutch bearing, or sprag clutch). The uni-directional couplings the alternately freewheel and transmit torque between the contra-rotating shafts and the outer concentric cylindrical hub, ensuring the outer concentric cylindrical hub only 25 rotates in the direction required and thereby transmits constant uni-directional torque to the rear wheel of the bicycle bymeans of a toothed gear or sprocket fixed thereon. The inner shaft also synchronises the left and right pedal assemblies to execute their forward and rearward motions in opposite directional sense. There is an aforementioned toothed gear fixed at the left end 9 the inner synchronising shaft enmeshed at the bottom of its rotation with the lower linear toothed rack in the left pedal assembly, and an extra -3synchronising toothed gear fixed at the right end of the inner synchronising shaft enmeshed at the top of its rotation with he upper linear toothed rack in the right pedal assembly. Therefore when one pedal moves rearward the other pedal must move forward. The right pedal assembly synchronises the inner and outer concentric shafts to always rotate in opposite rotational sense.

When the right pedal assembly moves forward or rearward the lower linear toothed rack fixed within enmeshes with the toothed gear fixed upon the outer shaft at the bottom of its rotation, and the upper linear toothed rack fixed within enmeshes with the toothed gear fixed upon the inner shaft at the top of its rotation, therefore, any direction the pedal assembly moves will always cause the two shafts to rotate in opposite rotational sense.

By achieving the first objective of this invention to efficiently convert linear motion to rotary motion, the second object is realised in that the rider pedals in a linear manner which closer approximates the body's natural leg movement. Also the third objective of this invention is realised in that the pedal stroke is infinitely variable between its forward and rearward limits therefore any rider will have will have a stroke length uniquely suited to their leg length, and the stroke can be varied at will to suit varying riding conditions.

The fourth, fifth, sixth, and seventh objectives of this invention are achieved by supporting the rider in a prone position in that the amount of atmospheric drag incurred by rider and bicycle is reduced, the riders centre of gravity is :lower to the ground than a conventional bicycle, the rider is supported comfortably and can relax in this position allowing energy wasted on maintaining posture to be channeled into pedaling, and finally the riders body is essentially straight not bent at 90 degrees at the pelvis therefore being more AZ--i conducive to physical exertion and eliminating the potential for postural i "Y'ilments.

-4- Still further objectives of the invention are to provide such a frame and driving mechanism which is simple and economical to manufacture and sturdy, durable, and trouble free in operation.

In one form of the invention, the pedal assemblies may follow a path that deviates from being straight when viewed in elevation. This path may be curved, but the pedaling remains linear on a curved path, the pedal assemblies do not pivot about any point.

In another form of the invention the path of the pedal assemblies may not be parallel when viewed from above and may execute their forward and rearward motions not parallel to each other nor to the longitudinal axis of the bicycle nor to the plane of rotation of the toothed gears. But having movement symmetrical about the longitudinal axis of the bicycle that converges towards the front of the bicycle, and diverges towards the rear of the bicycle.

*In another form of the invention the tubular frame of the bicycle is replaced by 15 a hollow, two sided, curved, structurally sound, continuous surface so shaped as to reduce atmospheric drag, and to contain within its surfaces moving parts including wheels and said drive mechanism, and any other parts deemed applicable.

*9eo a In another form of the invention an aerodynamic cowling is added to the frame 20 to reduce the atmospheric drag co-efficient.

In another form of the invention addition to or manipulation of the frame will increase the carrying capacity of the bicycle to carry items deemed necessary by the rider, including a baby carried safely in a baby seat, or an adult passenger carried safely, or an extra rider(s).

In another form of the invention the rotating parts of the drive mechanism andlor gear change assembly are mounted concentrically within the hub of the rear driven wheel of the bicycle.

In another form of the invention the front wheel may be replaced by two front wheels forming a tricycle.

In another form of the invention the bicycle may be adapted to be hand powered for use by people with disabilities to the legs.

In another form of the invention chain(s) and sprocket(s) may be used instead of andlor in conjunction with linear toothed rack(s) and toothed gear(s).

In another form of the invention the pedals are constrained to move in opposite directional sense, and the two concentric shafts are constrained to i: contra-rotate by left and right drive chains, one end of each being fixed to its .i respective pedal assembly, the other end being fixed to the other pedal S"assembly..

In another form of the invention the two concentric shafts are supported on the outside of the concentric hub.

Sq..

The frame and drive mechanism may be made of any suitable material including metals, metal alloys, plastics, wood, composite materials, or any other material deemed to be most suitable.

-6- In order that this invention may be more clearly understood and put into practical effect, there shall now be described in detail a preferred construction of a bicycle in accordance with the invention. The description is given by way of non-limitative example only and is with reference to the accompanying drawings, wherein; FIG 1 A view of the bicycle shown in elevation; and FIG 2 Across section through the drive mechanism in elevation looking rearward 9 9 -7- Referring to Fig 1 it can be seen that the bicycle frame and drive mechanism according to this invention comprises a frame 1 which supports the rider in the prone position by means of upper and lower torso supports 2 and 3 respectively, the handlebars 5, and by the pedals 4 which support the legs as well as transmitting propulsive force to the pedal assemblies 7 and 12. All body supporting components 1,2,4,5 are fixed and adjustable, with the exception of the lower torso support which may be pivoted to allow movement of the riders hips while pedaling.

The frame 1 also supports the drive mechanism 6 by rollers and roller guides 25, and by bearingassembly 23 the axis of which is at right angles to the longitudinal axis of the bicycle as shown in Fig 2. The drive mechanism 6 consists of a right pedal assembly 7 and fixed therein an upper linear toothed rack 8 and a lower linear toothed rack 9 enmeshed with toothed gears 10 and 11 respectively, also a left pedal assembly 12 and fixed therein a lower linear 15 toothed rack 13 enmeshed with a toothed gear 14.

S-The toothed gears 10 and 14 are supported by and fixed at opposite ends to an inner transversely mounted shaft 15 which, in addition to transmitting propulsive force, effects a synchronisation coupling between the two pedal assemblies 7 and12 forcing same to execute their forward and rearward 20 reciprocating motions synchronously and in opposite directional sense.

eO The toothed gear 11 is supported by and fixed to an outer transversely mounted shaft 16 which in turn is supported concentrically on the outside of the inner synchronisation shaft 15 and because the upper and lower linear toothed racks 8 and 9 being rigidly fixed within the right pedal assembly 7, and the lower linear toothed rackl3 being enmeshed with the toothed gear 14 and the lower linear toothed rack 9 being enmeshed with the toothed gear 11 will eii nsure that the inner shaft 15 and the outer shaft 16 will always rotate synhronously and in -8opposite rotational sense. Thereby whilst pedaling, one of the shafts 15 andl6 will always be rotating in the direction required to transmit torque.

Supported concentrically on the outside of part of the two shafts 15 and 16 is the outer hub assembly 17, there being disposed between shafts 15 and 16 and hub assembly 17 a uni-directional coupling for each shaft 24 so that despite the shafts 15 and 16 being contra-rotating, a continuous unidirectional torque is transmitted to outer hub assembly 17.

From outer hub assembly 17, which has a toothed sprocket 18 mounted thereon, propulsive force is then transmitted through a chain 19 to the rear wheel 20 via a gear change and sprocket assembly 21.

i* ft 9 4 *f 9*

Claims

1. A frame and drive mechanism applicable particularly to a bicycle, but usable also for other machines, the frame supporting the rider in a prone position in alignment with the longitudinal axis of the bicycle, head facing forward, the torso supported at the chest and pelvis, the arms supported conventionally by handlebars, and the legs supported on pedals, the pedals fixed to pedal assemblies which are constrained to move linearly forward and rearward synchronously and in opposite directional sense, parallel to each other and to the longitudinal axis of the bicycle, and fixed therein an upper and lower linear toothed rack in the right pedal assembly, and a lower linear toothed rack in the left pedal assembly which enmesh with and effect a rotation into toothed gears and the two concentric shafts the toothed gears are fixed upon, the two shafts being constrained to always contra-rotate and having fixed upon themselves uni-directional couplings which will alternately 15 free-wheel and transmit torque between the contra-rotating shafts and the outer concentric cylindrical hub ensuring the outer concentric cylindrical hub only rotates in the direction required to transmit constant uni-directional torque to the rear wheel of the bicycle by means of a toothed gear or sprocket fixed thereon. 20 2. A frame and drive mechanism of claim I whereby the left and right pedal assemblies execute their forward and rearward motions synchronously and in opposite directional sense by means of the inner synchronising shaft having .e upon it a toothed gear of claim 1 fixed at the left end of the inner S0. synchronising shaft enmeshed at the bottom of its rotation with the lower linear toothed rack in the left pedal assembly, and an extra synchronising toothed gear fixed at the right end of the inner synchronising shaft enmeshed at the top of its rotation with he upper linear toothed rack in the right pedal RAZ- assembly, therefore when one pedal moves rearward the other pedal must i/ ove forward.

3. A frame and drive mechanism of claim 1 wherein the right pedal assembly synchronises the inner and outer concentric shafts to always rotate in opposite rotational sense, when the right pedal assembly moves forward or rearward the lower linear toothed rack fixed within enmeshes with the toothed gear fixed upon the outer shaft at the bottom of its rotation, and the upper linear toothed rack fixed within enmeshes with the toothed gear fixed upon the inner shaft at the top of its rotation, therefore, any direction the pedal assembly moves will always cause the two shafts to rotate in opposite rotational sense.

4. A frame and drive mechanism of any one of the preceding claims wherein chain(s) and sprocket(s) are used instead of, and/or in conjunction with linear toothed rack(s) and toothed gear(s).

5. A frame and drive mechanism of claims I or 4 whereby the pedal assemblies are constrained to move synchronously and in opposite 15 directional sense, and whereby the two concentric shafts are constrained to

9. 9 rotate synchronously and in opposite rotational sense, by left and right drive chains, one end of each being fixed to its respective pedal assembly, the other end being fixed to the other pedal assembly. 6. A frame and drive mechanism of any one of the preceding claims wherein 20 The two concentric shafts are supported on the outside of the concentric hub. 7. A bicycle frame and drive mechanism of any one of the preceding claims, wherein the pedal assemblies may follow a path that deviates from being straight when viewed in elevation, this path may be curved, but the pedaling remains linear on a curved path, the pedal assemblies do not pivot about any Doint. -11 8. A bicycle frame and drive mechanism of any one of the preceding claims, wherein the path of the pedal assemblies may not be parallel when viewed from above and may execute their forward and rearward motions not parallel to each other nor to the longitudinal axis of the bicycle nor to the plane of rotation of the toothed gears, but having symmetrical movement that converges towards the front of the bicycle, and diverges towards the rear of the bicycle so as to greater facilitate an even more natural leg movement. 9. A bicycle frame and drive mechanism of any one of the preceding claims, wherein the tubular frame of the bicycle is replaced by a hollow, two sided, curved, structurally sound, continuous surface so shaped as to reduce atmospheric drag, and to contain within its surfaces moving parts including wheels and said drive mechanism, and any other parts deemed applicable.

10. A bicycle frame and drive mechanism of any one of the preceding claims, wherein an aerodynamic cowling is added to the frame to reduce the •oo.o: 15 atmospheric drag co-efficient

11. A bicycle frame and drive mechanism of any one of the preceding claims ,wherein addition to or manipulation of the frame will increase the carrying ee capacity of the bicycle to carry items deemed necessary by the rider, including °ee* a baby carried safely in a baby seat, or an adult passenger carried safely, or 20 another rider(s).

12. A bicycle frame and drive mechanism of any one of the preceding claims ,wherein, the rotating parts of the drive mechanism and/or gear change assembly are mounted concentrically within the hub of the rear driven wheel of the bicycle.