Folding two wheeled vehicle

Details Folding two wheeled vehicle Folding two wheeled vehicle

2000-08-25

2001-08-14

Johnson, Brian L. (Department: 3618)

Land vehicles

Wheeled

Occupant propelled type

C280S030000, C074S551300

Reexamination Certificate

active

06273442

ABSTRACT:

The present invention relates to a folding two wheeled vehicle such as a bicycle, a scooter or a lightweight pedal-assisted motorised bicycle, which may be folded so as to be easily portable when not in use as a vehicle.
BACKGROUND OF THE INVENTION
There are various designs of bicycles and scooters (hereinafter referred to simply as a bicycle) which may be folded for storage or carrying purposes. Some of these have a conventional bicycle frame of a diamond configuration and standard diameter wheels carried on arms hinged to the main frame, or removable wheels to permit folding of the frame. However, the shape and dimensions of these when folded often are most inconvenient for carrying. There have also been proposals where the main frame is designed to hinge to a collapsed position, with protruding parts hinging or telescoping with respect to the main frame, but these tend to be difficult to open out for use, or to collapse for carrying. Moreover, many designs are somewhat unstable when unfolded and so unsettling to ride. In an attempt to make a folding bicycle more easy to carry when folded, it is also known to provide a separate rigid case or flexible bag in which the collapsed bicycle is placed, but there then results the problem of transporting the case or bag, when the bicycle is in use.
In GB-2119324-A (Selars) there is described a bicycle having no main frame as such, but which has a part of a case serving as a main load bearing structure and into which may be folded a handlebar assembly and a seat assembly. The rear wheel is provided on an arm which may pivot round to lie partly within the case, the case being completed by a second part which when unfolded overlies the rear wheel. A disadvantage of this arrangement is that the main chain wheel (driven by the pedals) must be of a relatively small diameter to fit within the case and not protrude when the bicycle has been folded. To overcome this problem and obtain suitable gearing, a second large diameter chain drive wheel is provided on the pivoting arm section, so greatly adding to the mechanical complexity and weight of the structure, as a whole.
WO-85/01711-A (Miller) shows a bicycle with a case having a section hinged to the main part of the ease, to reduce the side area of the case and so to expose the rear wheel. The front wheel is arranged to be folded out and then locked in a position adjacent the lower front edge of the case. The disadvantage of this arrangement is that the length of the case will determine the distance between the front and rear wheels when the bicycle is unfolded as the location of the rear wheel axle is fixed within the case and the front wheel axle cannot lie significantly beyond the vertical front edge of the case. Since a bicycle must have a certain minimum dimension between the front and rear wheel axles for safety in use, a relatively long and consequently heavy case is required.
WO-83/03232 (Licencia Talalmanyokat) shows a bicycle which may be folded down to form a case-like structure, the case being defined by structural parts which are pivoted together and form the frame, when opened out. Such an assembly, having many pivoted parts, does not provide a rigid structure defining the required geometery for a bicycle and of necessity it has a very low gearing.
SUMMARY AND OBJECTS OF THE INVENTION
A principal aim of the present invention is to mitigate the disadvantages of the various known designs of folding bicycles, as described above, and so to provide a two wheeled vehicle which may be constructed to be light, safe in use and yet fold into an integral casing of a size which allows easy carrying or storage when not in use.
According to the present invention, there is provided a folding two wheeled vehicle comprising:
a substantially rigid unitary main structural component defering a head section for supporting a steerable front wheel, a saddle pillar mount and a bottom bracket rotatably supporting a pedal-shaft;
a rear wheel sub-frame pivoted to the main structural component about the axis of rotation of the pedal-shaft and rotatably supporting a rear wheel, the sub-frame being arranged for movement between a folded position where the rear wheel lies within the main structural component, between the head section and the saddle pillar mount, and an active position where the sub-frame projects rearwardly beyond the main structural component;
a first drive wheel carried by the pedal-shaft, a second drive wheel connected to the rear wheel, and an endless flexible tension member passing directly round the first drive wheel and the second drive wheel whereby rotation of the pedal-shaft drives the rear wheel;
a front wheel carrier journalled to the head section of the main structural component and having an arm rotatably supporting a front wheel, the arm being pivoted to the carrier for movement between a folded position where the front wheel lies adjacent but in substantially the same plane as the rear wheel when the sub-frame is in its folded position, and an active position where the arm projects generally downwardly from the carrier; and
the main structural component defining or carrying panelling comprising two opposed side panels, the panelling being dimensioned so that the folded rear wheel sub-frame, rear wheel, front wheel carrier, folded arm, front wheel and first drive wheel all lie substantially wholly within the confines of the side panels, the rear and front wheels lying outside the confines of the side panels when the sub-frame and arm are in their respective active positions.
With the arrangement of this invention, there is a fixed relationship between the head section in which is journalled the front wheel carrier, the saddle pillar mount and the bottom bracket, which normally supports the pedal shaft. The relationship between these components remains constant, when the bicycle is both in its folded position and in its active (unfolded) position. In this way, the main frame of the bicycle may have the dimensions and geometry of a conventional “double-diamond frame” adult bicycle, whilst still being collapsible to a size which is readily portable.
In a preferred form of the invention, the main structural component comprises a rigid frame made up from a plurality of frame members connected together, with the panelling mounted on the frame. Conveniently, the frame may be of a space-frame construction fabricated for example from metal tubing or other material such as carbon fibre whereas the panelling may be moulded from plastics material or pressed metal. In the alternative, said two side panels may be moulded to have a relatively strong and rigid form, the panels together forming a casing defining the main structural component. The panelling thus forms a kind of monocoque construction, obviating the need for a separate frame within the panelling. Equally, the rear wheel sub-frame could be a moulded structural component.
The vehicle of this invention is primarily intended to take the form of a folding bicycle and it will hereinafter be described exclusively with reference to a bicycle. It is however to be understood that the invention is not to be regarded as limited to a bicycle.
By having the rear wheel drive arrangement as specified above, the distance between the first and second drive wheels will not change despite pivoting movement of the rear wheel sub-frame above the bottom bracket and so the tension in the endless tension member will remain constant, irrespective of the position of the rear wheel sub-frame. Thus, a conventional chain wheel set may be employed, wherein the first and second drive wheels respectively comprise sprockets and there is an endless chain extending round said sprockets, though it would be possible to use a toothed belt together with suitable pulleys.
The pedal shaft carries a pair of opposed pedals; these pedals may be folded to lie parallel to the case or released from the shaft when not required for use. By having each pedal on a respective crank arm, the crank arm itself may be releasably connected to the pedal shaft, to permit removal of the

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