COMPONENT FOR A BICYCLE TO REDUCE AERODYNAMIC DRAG

This invention relates generally to the field of bicycles and bicycle handlebars. More specifically the present invention relates, without limitation, to the aerodynamic elements attached, modified or blended to one or more components of a bicycle that are rotated with respect to the normal airflow.

In the world of bicycle racing the difference between success and failure can, in some circumstances, be measured in fractions of a second. The power which a cyclist can generate to propel a bicycle is limited by the cyclist's physical ability however the maximum performance a cyclist can achieve is eroded by the power requirement increasing as aerodynamic drag increases. Although the bicycle itself contributes to the overall aerodynamic drag that a cyclist must contend with it is known that the largest contributor to aerodynamic drag of the bike and cyclist system is the cyclist's body itself which contributes around 70 - 80%, dependent on body shape and position, of the overall aerodynamic drag of the system.

Improvements in the competitiveness of cyclists over the past 20 plus years has been derived from a combination of a reduction in bicycle component weight, whether by use of lighter materials or optimisation of manufacturing design, and in aerodynamic drag of the individual structures of the bicycle, such as the frame, wheel, forks and handlebar, and the rider. Current practice has been to attempt to reduce the drag of each and every individual component based on the concept that the cumulative reduction in aerodynamic drag is a result of the sum of the individual component reductions achieved. Further reductions have been achieved by cyclists continuously trying to improve their aerodynamic position while cycling. This has been achieved by a number of means, including producing handlebars that aim to put the cyclist in a position such that it minimises the frontal area of the rider or optimising a position that balances comfort with efficiency, such variance being required to address the wide range of racing durations which can last from less than a minute to several hours.

In combination with the design changes that have optimised the aerodynamic position of the cyclist the handlebars themselves have also been optimised to reduce the aerodynamic drag they contribute. Such optimisation is generally in the form of replacing the traditional tubular shaped construction with aerodynamic construction, whereby the usually symmetrical aerodynamic shape hits the airflow usually at zero degrees angle, which is parallel to the airflow. Although the majority of work relating to handlebar design has been related to the so-called aerodynamic handlebars which incorporate a means to optimise the aerodynamic position of the cyclist, some development of the traditional drop handlebars seen on both road racing bikes and some of the velodrome races, has been made to incorporate aerofoil structures.

Hence bicycles in all their variations and developments suffer a disadvantage in that they have failed to address the fact that in a complex system such as a bicycle and cyclist there are a plethora of interactions among the different components. In particular the body of the cyclist is a 'bluff body' which dominates the overall drag values mainly because of the low pressure region that is formed behind the cyclist. Although the streamlining and optimisation of the individual component design to maximise aerodynamic efficiency reduces the drag on the individual components as well as the bicycle itself it does nothing to address the problem of the highest drag contributor, the cyclist's body.

In view of the above there exists a need for an aerodynamic component that is optimised in redirecting the airflow to achieve an overall reduction in the aerodynamic drag of the combined bicycle and cyclist system rather than the component itself. This invention addresses this need in the prior art.

Summary of Invention

As used herein, the following directional terms "forward", "rearward", "vertical", "horizontal", "transverse", "inwards", "outwards" as well as any other similar directional terms refer to those directions of a bicycle from the cyclist's perspective in the normal riding position with the cyclist sitting on a bicycle facing in the direction of travel and the bicycle being upright and perpendicular to the ground. Where angles are defined these are with reference to the horizontal plane being 0° and the

common engineering notation of counter clockwise being positive to denote the right hand side and left hand side. Accordingly, these terms, as utilised to describe the present invention should be interpreted relative to bicycle 1 in Figure 1 in its normal riding position.

To overcome the disadvantages of the aerodynamic drag of the combined bicycle and cyclist system the present invention provides a component for a bicycle having a plurality of elements one or more of which may have an aerodynamic shape and when viewed in cross-section that shape may be an aerofoil. The elements may be at an angle to the airflow but may also be twisted so as to be at an angle other than 0°.

The primary object of the invention is the manipulation and/or modification of the airflow around the system by changing the geometry of an existing component on a bicycle in order to achieve a lower overall drag coefficient of the bicycle and cyclist system regardless of the overall effect on the drag coefficient of the component itself. Preferably that component is a handlebar.

Another object of the invention is to provide a component that is relatively lightweight yet robust enough to ensure that it is capable of supporting the weight of a cyclist.

Another object of the invention is to provide a component that is a handlebar that provides multiple gripping positions.

Still another object of the invention is to provide a handlebar that comprises a system that enables elements to be adjustable to suit the individual cyclist. The handlebar can be a variety of different types including a drop style handlebar or handlebars designed for time trials. The handlebar may contain many additional elements common to conventional handlebar systems available on the market, including arm rest holders and pads, extensions and brake and gear levers.

The present invention provides a component for a bicycle the component being formed from a plurality of elements, characterised in that at least one of the elements has an aerofoil cross-section having a leading edge and a trailing edge being twisted

such that the leading edge is directed outwards and the trailing edge is directed inwards thus directing the airflow towards the cyclist.

In accordance with the present invention the component has an external surface and preferably that external surface is designed to be an aerodynamic shape. In particular the component comprises elements at least one of which has a cross- section preferably of an aerofoil shape, hereinafter called an aerofoil element. Furthermore the aerofoil element can have a symmetrical cross-section or have a cambered cross-section. Preferably the aerofoil has an enlarged rounded forward end and a reduced size at the rearward end.

The component will have at least one aerofoil element which comprises an aerofoil cross-section being configured so as to modify the airflow so as to cause the airflow to be directed towards the cyclist. The external profile of the component can be adapted such that the aerofoil element may be at an angle other than 0° with respect to the horizontal plane. Preferably the aerofoil element will be at an angle of ± 40° from the vertical plane, more preferably the aerofoil element will be at a range of ± 10 - 20° from the vertical plane. The aerofoil element may be twisted with respect to the chord line of the aerofoil. Preferably the aerofoil element will be twisted such that the profile of the aerofoil will have its leading edge outwards and its trailing edge inwards so as to modify the airflow so as to cause the airflow to be directed towards the cyclist. More preferably the aerofoil element will have a twist of between +5° and +25° when on the left hand side and between -5° and -25° when on the right hand side.

Where the component is a handlebar for the optimum performance of a NACA 14533-44 aerofoil it should be twisted at or about +7° on the left hand side and - 7° on the right hand side.

Bicycles include a main frame to which a front fork is pivotably mounted through the bore of a head tube, a lower end of the fork being adapted to accommodate a wheel and an upper end of the fork being adapted to interface with a handlebar via a bicycle stem. The handlebars are the component of the bicycle that enables the cyclist to steer the bicycle they also provide one of the means to which additional

components may be attached. Preferably the additional components include a means to operate the bicycle braking system or a means to operate the bicycle gear system. More preferably the handlebars accommodate systems to operate both the bicycle braking system and the bicycle gear system. Even more preferably the handlebars accommodate a single system to operate both the bicycle braking system and the bicycle gear system.

Furthermore the handlebar may be adapted dependent upon the use to which the bicycle is to be put. Such adaptations may include the addition of one or more extension bars; the extension bars may be formed from a single element or from a plurality of elements projecting from the handlebar that enable the cyclist to position themselves in an aerodynamically advantageous position. The handlebar and extension bars can be adjustably mounted to enable a plurality of positions to be achieved or the extension bars can be an integrally formed part of the handlebar. The extension bars can project forward or rearward, preferably projecting forward.

Further the handlebar may have the addition of an armrest projecting from the handlebar to further enable the cyclist to position themselves in an aerodynamically advantageous position. The handlebar and armrest can be adjustably mounted to enable a plurality of positions to be achieved or be an integrally formed part of the handlebar.

Furthermore the extension bars and armrest can be adapted as mating components or integrally formed as a single component. Still furthermore, the handlebar, extension bars and armrest can be integrally formed as a single component.

The extension bars and/or the armrest and/or any integrally formed combination of the two can be integrated with the handlebars by means of an additional element, such elements can be on the upper or lower surface of the handlebars and the additional element may be formed from the aerofoil element. Any combination may be integrally formed with the additional element and the handlebar to form a single component.

The armrest may have an arm rest pad fitted for the comfort of the cyclist, such pads may be of a plurality of thickness to provide adjustment to further improve the cyclist's comfort. The handlebars may also have a plurality of handgrips to enable the cyclist to achieve optimum control of the bicycle.

The handlebar may have a stem which secures the handlebar to the front fork or a mounting plug which extends downwards into an internal bore of the head tube. Preferably the stem has mating surfaces which engage with the interior and/or exterior surfaces of the front fork such that the stem and handlebar are prevented from rotating about the front fork. Preferably the outside profile of the stem at the mating surface is complementary to the outside profile of the head tube.

In an alternative embodiment the handlebar and stem are integrally formed.

The stem, however formed, can be attached to the bicycle forks by a variety of means including bolts, a quill system using a wedge and bolt or a cone shaped expanded nut and bolt, a split clamp or pinch clamp. In addition the stem can be removed from the handlebar and replaced with an alternative stem if desired.

Further, the stem may give the handlebars a fixed height relative to the bicycle frame or alternatively it may be adapted such that the height of the handlebar relative to the bicycle frame may be varied. The means of varying the height may be any suitable means for example by the addition or subtraction of a plurality of spacing elements.

Brief Description of the Drawings

Figure 1 is a schematic side view of a bicycle (known in the prior art).

Figure 2 is a cross-section view taken along the line E - E of Figs 5, 11 and 16 of the aerofoil element.

Figure 3 is a cross-section view along the line Y - Y of Figs 5, 11 and 16of an aerodynamic element.

Figure 4 is a plan view of an integrally formed drop style handlebar of the invention.

Figure 5 is a perspective view of an integrally formed drop style handlebar of the invention.

Figure 6 is a rear view of an integrally formed drop style handlebar of the invention.

Figure 7 is a right side view of an integrally formed drop style handlebar of the invention.

Figure 8 is a plan view of a drop style handlebar of the invention.

Figure 9 is a rear view of a drop style handlebar of the invention.

Figure 10 is a right side view of a drop style handlebar of the invention.

Figure 1 1 is a perspective view of an integrally formed drop style handlebar of the invention attached to a bicycle showing aerodynamic section Y - Y and aerofoil element section E - E.

Figure 12 is a perspective view of an integrally formed drop style handlebar of the invention attached to a bicycle.

Figure 13 is a plan view of an integrally formed time trial style handlebar of the invention.

Figure 14 is a perspective view of an integrally formed time trial style handlebar of the invention.

Figure 15 is a plan view of a time trial style handlebar of the invention.

Figure 16 is a perspective view of an integrally formed time trial style handlebar of the invention attached to a bicycle showing aerodynamic section Y - Y and aerofoil element section E - E.

Figure 17 is a perspective view of an integrally formed time trial style handlebar of the invention attached to a bicycle.

Detailed Description of the Preferred Embodiments

Figure 1 shows a bicycle 1 comprising a frame 2, which incorporates a head tube 3 that connects a handlebar 4 with a front fork 5 via a stem 6.

Figure 2 shows cross-section E - E through an aerofoil element.

Figure 3 shows cross-section Y - Y through an aerodynamic element

First e m bodiment

Figure 5 is perspective view, Figure 4 shows a plan view, Figure 6 shows a rear view and Figure 7 shows a right side view of an embodiment of the invention with a drop style handlebar. As shown the handlebar 4 is configured in the known drop handlebar style and is integrally formed from a stem 41 , a stem transition centre element 42 and a bar 43. The bar 43 has a drop style profile which is symmetrical about centre line C - C and D - D. The bar 43 is integrally formed from a horizontal central element 431 , which has an aerodynamic cross section Y - Y, and a horizontal forward sweeping element 432a and 432b which transitions to a handgrip 433a and 433b via a downward curving aerofoil element 434a and 434b. A cross section E - E showing the aerofoil is at Figure 2.

Figure 8 is a plan view, Figure 9 is a rear view and Figure 10 is a right side view of the drop style handlebar 4 as described in the first embodiment above where the bar 43 and the stem transition centre element 42 are individual components that are designed such that they co-operate with each other at point 400 and can be fixed together by any mechanical means.

Figure 11 shows handlebars according to the invention of the first embodiment fitted to a bicycle, where the handlebars are sectioned showing the aerodynamic cross- section Y - Y and aerofoil element cross-section E - E.

Figure 12 shows handlebars according to the invention of the first embodiment incorporated into a bicycle.

Second embodiment

Figure 14 is perspective view and Figure 13 shows a plan view of an embodiment of the invention with a time trial style handlebar. As shown the handlebar 4 is integrally formed from a stem 51 , a stem transition centre element 52 and a bar 53. The bar 53 has a profile symmetrical about the centre line X - X and terminates in a handgrip 54a and 54b. The profile of the bar 53 has a horizontal centre section 531 transitioning at either end via a downwardly curved element 532a and 532b terminating in handgrip 54a and 54b. The bar 53 has an aerodynamic cross section Y - Y. The upper surface of the bar 53 has integrally formed risers 55a and 55b, each is integrally formed with an arm rest 56a and 56b and an extension bar 57a and

57b. The risers 55a and 55b have an aerofoil cross-section E - E shown in Figure 2 forming the aerofoil element of the handlebar 53.

Figure15 is a plan view of the time trial style handlebar 4 as described in the second embodiment above where the bar 53 and the stem transition centre element 52 are individual components that are designed such that they co-operate with each other at point 500 and can be fixed together by any mechanical means. Further the risers 55a and 55b are individually formed to co-operate with the arm rests 56a and 56b respectively and the individually formed extension bars 57a and 57b to be fixed together by any mechanical means.

Figure 16 shows handlebars according to the invention of the second embodiment fitted to a bicycle, where the handlebars are sectioned showing the aerodynamic cross-section Y - Y and aerofoil element cross-section E - E.

Figure 17 shows handlebars according to the invention of the second embodiment incorporated into a bicycle.

In an alternative embodiment not illustrated the integrally formed risers 55a and 55b with armrests 56a and 56b and extension bars 57a and 57b can be integrally formed with bar 43 as described in embodiment 1.