GB2439937A

GB2439937A - Variable riding position bicycle

Info

Publication number: GB2439937A
Application number: GB0613913A
Authority: GB
Inventors: Joshua Nicholas George Reid
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-07-13
Filing date: 2006-07-13
Publication date: 2008-01-16
Also published as: GB0613913D0

Abstract

The bicycle (9), which can be power driven, comprises a front wheel (15) carried by a front fork (1) connected to a front member (3) connected to upper and lower crossbars (6, 7), and a seat bracket (8) that is connected to the upper and lower crossbars; all connections use pivots. The bicycle also comprises a rear fork (11) for a rear wheel (14), connected to the seat bracket (8) and to a rear link (12), pivotally connected to the lower crossbar (6). The various frame members are connected such that they can pivot to provide positions for the seat bracket (8) at a position low down between the wheels (14, 15) for recumbent use or a position up above them for conventional use, which last position is characterised by a shorter distance between the wheels. One or more hydraulic actuators are used to move and lock the frame parts. The seat bracket (8) carries a seat back.

Description

I

Variable riding position bicycle The invention relates to a bicycle (9) comprising, a front wheel (15) connected to a front fork (1), a front member (3) which is connected to the front fork (1), to the upper crossbar (6) and to the lower crossbar (7), and a seat bracket (8) that is connected to the upper and lower crossbars, in which the pivotable connecting points (a), (b), (c), (d) are situated at various distances from one another, which bicycle furthermore comprises a rear fork (11) which is connected to the rear wheel (14), to the seat bracket (8) and to the rear link (12), furthermore the rear link (12) is connected to the lower crossbar (6), in which the members (3,6.7,8,1 1,12) are connected such that they can pivot between positions charactensed in that the seat bracket (8) may be at a position low down between the wheels (14,15) or a position up above them, which last position is characterised by a shorter distance between the wheels.

Known bicycles of different types employ a variety of frame configurations. These range from the classical conventional layout in which the rider sits on a saddle or seat located at a level commensurate with waist level, to a configuration which places the seat much closer to the ground and the pedals higher and further forward to maintain a proper gap between seat and pedals. Bicycles with a low seat configuration are commonly known as recumbent bicycles.

Recumbent bicycles offer several advantages over upright bicycle frame configurations. Low riding position bicycles present less cross section than upright designs thereby creating less aerodynamic drag and improving overall efficiency.

Recumbent bikes represent a further advantage over upright designs in their seat configuration which if. in its embodiment, creates a back rest allows the rider to use the seat to react the force exerted on the pedals. Normally this reaction force is provided by a combination of gravity acting on the riders body and the rider using their arms to pull downwards on the handle bars reacting the vertical force applied downwards to the pedals by the riders feet.

However low riding position bikes present several drawbacks over conventional designs these being: poor manoeuvrability and turning circle, instability at low speeds, inability to climb curbs, inability to jump hard down on the pedals while hill climbing at low speed and the configuration often forms a large and complex shape hard to store and transport on trains and using motor vehicles.

It is an object of the present invention to overcome some of the drawbacks associated with both upright and recumbent configuration bicycles in a bicycle frame that allows transition between the form of an upright configuration, and the form of a recumbent bicycle, and forms in between.

With reference to figs 1-9 To achieve a clean line to prevent fouling the legs whilst riding the vehicle uses a single froni member (3) that hugs the wheel and runs down between the wheels providing a gap at the midsection of the vehicle to house the pivotable joints that connect to the upper and lower crossbars (6&7). The upper and lower crossbars extend upwards at an angle from their pivot joint connections made with the front member to pivotable connections made with the seat bracket. When the bike moves into the recumbent mode (fig 6) the upper and lower crossbars lie back, with the seat bracket (8) providing the last element in a four bar linkage between points (a), (b), (C), (d). In order to provide a controllable linkage structure the rear fork (11) must be actuated by a linkage, the rear link (12). The rear link moves the rear fork to a broadly horizontal position. without the rear link the rear fork would be on a free pivot and the bicycle would ground. In the low riding position the elements of the frame lie flat making efficient structural use of the material.

The preferred embodiment uses a gas spring to actuate the frame though there are many types of actuator that would suffice.

The preferred embodiment positions the frame actuator between the upper and lower crossbars, further actuators may be employed for example running broadly vertically between the seat bracket and rear fork.

In the preferred embodiment the frame actuator is lockable so the bike can be locked in a riding position between fully up and fully down (fig 6), it is preferred that, when locked, the actuator is still able to provide a spring force over a small displacement to provide suspension.

The seat may be rigidly connected to the bracket, but in the preferred embodiment the seat is connected via a pivot joint. The preferred embodiment uses the seat link (22) to control the angle of the seat on its pivot, as the bicycle transforms between modes. The preferred embodiment uses a seat with a back which is rigidly connected to the seat, but embodiments in which the seat angle may be controlled individually by a separate link, with pivot joints at either end and attached to the frame in a similar manner to the seat link is considered.

The preferred embodiment includes pedals, the position of which should be controlled to raise them and move them forward when the bike transforms to the lower riding position. This is achieved in the preferred embodiment by connecting the pedals such that they can rotate in a pedal connector (16) and hence drive the chain and by further connecting the pedal connector (16) to the front member (3).

The pedal link (17) is connected to the lower crossbar (7) such that the desired movement is achieved during fame transformation.

The preferred embodiment the bicycle is driven by a chain which runs around a sprocket attached to the pedals and a sprocket attached to the rear wheel and is guided by a guiding means in the area substantially below the seat.

In the preferred embodiment the bicycle is provided with gears, though gears are not an essential element of the invention.

The vehicle may be provided with a motor to provide motive power using stored energy held on the vehicle, although if a motor is employed it is preferred that the vehicle is additionally able to be human powered.

City livers who run for sport sometimes run on the spot whilst waiting at traffic control lights in order not to break their stride. By the same theory means may be provided that the user may pedal without moving the vehicle but powering a generator that charges some stored energy means such as a flywheel, hydraulic/pneumatic accumulator or chemical reaction, which may then release the stored energy when* motion is recommenced.

The bicycle may be provided with breaks.

The bicycle may be provided with positions for carrying loads such as panniers and racks. It may also be provided with positions for carrying passengers.

The human transport device may include shaped parts to act to lower the aerodynamic drag of the device.

Figure 1 shows the frame layout in the lowest riding position mode.

Figure 2 shows the frame layout in the lowest riding position mode including the actuator and pedal configuration Figure 3 shows the frame layout in the lowest riding position mode including the actuator, chain, sprocket and pedal configuration Figure 4 shows a detail of the seat bracket in the lowest riding position mod Figure 5 shows the device in the highest riding mode.

Figures 6-9 show intermediate height riding modes.

Claims

Claims A bicycle (9) comprising, a front wheel (15) connected to a

front fork (1), a front member (3) which is connected to the front fork (1), to the upper crossbar (6) and to the lower crossbar (7), and a seat bracket (8) that is connected to the upper and lower crossbars, in which the pivot able connecting points (a), (b), (C), (d) are situated at various distances from one another, which bicycle furthermore comprises a rear fork (11) which is connected to the rear wheel (14), to the seat bracket (8) and to the rear link (12), furthermore the rear link (12) is connected to the lower crossbar (6), in which the members (3,6,7,8,11,12) are connected such that they can pivot between positions charactensed in that the seat bracket (8) may be at a position low down between the wheels (14,15) or a position up above them, which last position is charactensed by a shorter distance between the wheels.

2. A bicycle (9) according to claim 1, which includes pedals (18) connected such that they can rotate in a pedal connector (16), in which said pedal connector is connected to the front member (3) and a pedal link (17) which pedal link is connected to the lower crossbar (7). in which connections are made such that the members pivot.

3. A bicycle (9) according to claim 1, that is further provided with an actuation means (19) that is connected at both ends to two distinct members of the pivoting frame (10) characterised in that as the actuator changes length such that the seat bracket (8) may be at a position low down between the wheels (14,15) or a position up above them.

4. A bicycle (9) according to claim 1, that is provided with a handle bar stem (20) connected to a handle bar (21), the front fork (1) and an actuation means, which said actuation means is also connected to the front fork charactensed in that the handle bar stem can rotate relative to the front fork, and in that the actuator ends are connected using pivots.

5. A bicycle (9) according to claim 1, that is provided with a seat (13) connected to the seat bracket (8) and a seat link (22) by pivotable joints, in which the said seat link connects to the lower crossbar (7) by a pivotable connection such that the angle of the seat is canted front down when the frame is in the higher position and the seat is canted front up when the frame is in the lower position.

6. A bicycle (9) according to claim 5, in which a seat back (23) is rigidly or otherwise connected to the seat (13).

7. A bicycle (9) according to claim 1, that is provided with an electric, pneumatic, hydraulic, internal combustion engine or other means that provides stored motive power.

8. A bicycle (9) according to claim 1, that is human powered.

9. A bicycle (9) according to claim 1. that is human powered in which the rider drives a generator such that the rider may pedal while the vehicle is stopped. storing power which is then used for motive power when motion is recommenced.

10. A bicycle (9) according to claim 8. in which the pedals are connected to the rear wheel by a traction chain drive with the said chain guided by a guiding means (24) located in the area below the seat (8).

11. A bicycle (9) according to claim 1, in which one or more actuator is a gas strut.

12. Human transport device (9) according to claim 1, in which one or more actuator is provided with a means for locking its displacement.

13. A bicycle (9) according to claim 1, in which one or more actuator is provided with a means for locking ifs displacement which is remotely controllable by a lever or button in the handlebars.

14. A bicycle (9) according to claim 1, in which one or more actuator has an elastic-spring and damping action providing suspension.

15. A bicycle (9) according to claim 1. which employs multiple frame actuators in different positions linking the frame members.

16. A bicycle (9) according to claim 1, in which the upper crossbar and lower crossbar are extensible to provide adjustment for a range of riders.

17. A bicycle (9) according to claim 1. characterised in that if has a depth stop or boss on the upper crossbar that comes into contact with the lower crossbar to provide a lower height limit in the movement of the seat and frame.

18. A bicycle (9) according to claim 1. in which the length of the handle bar stem (20) is adjustable.

19. A bicycle (9) according to claim 1, in which one or more of the pivoting frame members is replaced by two distinct mirrored bodies with concentric axes of pivot such that they perform the function of a single member positioned at their mirror plane.

20. A bicycle (9) according to claim 19. in which the two distinct bodies are not mirrored bodies but share axes of revolution.