For many years, bicycle frames have been fitted with flexible transmission elements such as brake cables or hoses, shifting cables, and electric wires in order to allow the rider to control the bicycle's functions such as shifting gears, turning on lights or batteries for electric motors, or applying the brakes. These flexible transmission elements are generally routed externally of the frame of the bicycle for easy maintenance and low cost assembly. Increasingly, bicycles are becoming equipped with more electronic equipment and even electric batteries, controllers, and electric motors in the case of electric bicycles, and this is requiring more control cables, hoses or wires to be fitted. The result of this is that the aesthetic appeal of the bicycle is substantially reduced due to a "cluttered" appearance from the many control cables, hoses or wires and these externally routed elements are more prone to damage, when the bicycle is leant against a wall or post for example.

Some modern bicycles have some cables internally routed inside the frame of the bicycle to protect the cables from damage, enhance the visual appeal of the bicycle, and in some cases to improve aerodynamics of the frame. However, due to the required turning of the handlebars for steering the bicycle, control cables cannot be routed completely internally from the handlebars directly into the frame because when the rider turns the handlebars - and in some cases this can be turned through 90 degrees or more - the control cables will bend and buckle, causing damage and loss of control of the components. So there is a small length of control cables that are external between the handlebars and the frame of the bicycle to allow the cables to move freely and not bend or buckle when the handlebar is turned. Some solutions for this are to have a hole in the steerer tube of the bicycle such that the cables can pass through the hole and run internally into the handlebars and then exit close to the brake levers and shifting controls, however a bicycle steerer tube is a highly structurally loaded part and a hole through this component is potentially unsafe. This solution also tends to put the cables into bending and buckling when the handlebars are turned and if not carefully created with rounded corners, the hole can cut and damage the control cables.

The present invention addresses this problem of internally routed cable bending and buckling by providing a steerer tube and steering bearing headset to facilitate internal cable routing by aligning the cables such that when the handlebars are turned, the control cables twist instead of bend or buckle. Cables or hoses have a high degree of flexibility if twisted through their length instead of bending - which can result in buckling and damage. Accordingly, this invention provides a new and improved steerer tube and bearing clamp design with a cable guiding facility that allows for internal cable routing with no extemally visible cable routing between the handlebar and frame allowing the cables to twist as the handlebar turns.

According to a first aspect of the invention, there is provided a bicycle including a frame, and a handlebar and front fork assembly including a steerer tube mounted to the frame for rotation relative thereto, wherein the steerer tube is supported in upper and lower annular bearings mounted to the frame, and wherein the steerer tube has a non-circular cross-section at the upper annular bearing, and wherein one or more flexible transmission elements pass through the upper annular bearing outside the cross-section of the steerer tube.

In one embodiment, the bicycle may further include a cable guide adapted to extend through the upper annular bearing and to define a passage extending axially of the steerer tube between the cable guide and the steerer tube.

The cross-section of the steerer tube at the upper annular bearing may comprise a substantially planar diametral wall and a semicircular wall, forming a "D" shape.

The cable guide may comprise a pair of walls and define a substantially triangular-section passage with the diametral wall of the steerer tube. A second aspect of the invention provides a bicycle frame and front fork assembly, wherein the front fork is mounted to one end of a steerer rube, and the steerer tube is mounted to the frame for rotation relative thereto, wherein the steerer tube is supported in upper and lower annular bearings mounted to the frame, and wherein the steerer tube has a non-circular cross-section at the upper annular bearing such that one or more flexible transmission elements may be passed through the upper annular bearing outside the cross-section of the steerer tube.

According to a third aspect, there is provided a steerer tube for mounting to a bicycle frame by means of upper and lower annular bearings surrounding the steerer tube at bearing locations spaced along the axial length of the steerer tube, the steerer tube having a non-circular cross-section at the bearing location of the upper annular bearing.

A fourth aspect of the invention provides a front fork assembly for a bicycle comprising a steerer tube as described above and one or more fork blades mounted to the end of the steerer tube adjacent the lower bearing location and adapted to support a bicycle wheel. At least one of the fork blades may have a hollow structure, and the interior of the fork blade may be in communication with the lumen of the steerer tube. The fork may comprise a single fork blade.

A preferred embodiment of the invention will now be described with reference to the accompanying drawings, in which:

FIGURE 1 is a perspective view of a bicycle in accordance with the invention;

FIGURE 2 is a perspective and exploded view showing the steerer tube of the bicycle of Figure 1 with the frame partially cut away for clarity;

FIGURE 3 is a perspective view similar to figure 2, showing the components in their assembled condition with the frame partially cut away for clarity;

FIGURE 4 is a sectional side view along the axis of the steerer tube;

FIGURE 5 is a transverse sectional view at the location of the upper bearing; and

FIGURE 6 is a transverse sectional view through the headset clamp showing the clamping arrangement to the fork steerer tube. Referring now to Figure 1 , there is shown a bicycle 17 comprising a headset clamp and fork steerer tube assembly 1 receiving a bicycle handlebar stem assembly 18.

As shown in the exploded view FIGURE 2, the bicycle includes a headset clamp 2 with stem fixing holes 6 for receiving a bicycle handlebar stem assembly such as with bolts or quick release mechanism and headset clamp holes 8 for receiving headset clamp screws 9.

The headset clamp 2 is made to receive the cable guide wedge 10 which can accept through a headset preload screw 12 fastenable to fork steerer tube 3. The cable guide wedge 1 0 comprises a generally "V" section wedge, with a cap part 10a at its upper end. Cap part 10a includes a first opening 10b which aligns, in use, with the lumen of the steerer tube 3. A second opening 10c in the cap part 10a aligns with the interior of the "V" shape of the table guide wedge 10.

Fork steerer tube 3 has a lower fork section 16 made to receive a standard bicycle wheel. Fork steerer tube 3 is rotatably mounted on lower headset bearing 4 and upper headset bearing 5. Fork steerer tube 3 is formed such that cables 1 1 required to enter within the interior of the frame 7 can pass through the second opening 10c in the cap 10a, between the cable guide wedge 10 and the steerer tube 3, and then into the interior of the frame 7. Cables 13 required to pass down W

7 into the front fork blades enter through the first opening 10b in the cap 10a, and pass through the interior of the steerer tube 3. All of the cables thus pass through the annular upper headset bearing 5.

Internal fork cables 13 pass through cable guide wedge 10 and through headset clamp 2 and into fork steerer tube 3 and can run internally through lower fork section 16 in order to connect with electronics, brakes, or lighting components of a standard bicycle wheel and hub. Lower headset bearing 4 and upper headset bearing 5 are fitted to bicycle frame 7 using standard and well understood methods.

Fork steerer tube 3 can be formed from metal alloys such as aluminium, or from carbon fibre or other composite materials. The method of construction could be hydro forming, forging, moulding, or welded fabrication or milling and turning. The materials of headset clamp 2 and cable guide wedge 10 will ideally be metal alloys such as aluminium and of forged or milled from solid construction.

FIGURE 3 shows a headset clamp 2 with stem fixing holes 6 for receiving a bicycle handlebar stem assembly such as with standard bolts or a standard bicycle quick release mechanism and headset clamp holes 8 for receiving headset clamp screws 9. The headset clamp 2 is made to receive the cable guide wedge 10 which has a clearance hole on the pivoting axis of the steerer tube 3 to accept through it a headset preload screw 12 fastenable to fork steerer tube 3. Fork steerer tube 3 has a lower fork section 16 made to receive a standard bicycle wheel. Fork steerer tube 3 is rotatably mounted on lower headset bearing 4 and upper headset bearing 5. Fork steerer tube 3 is formed such that internal frame cables 1 1 can pass through upper headset bearing 5, headset clamp 2 and through the passage between cable guide wedge 10 and the steerer tube 3. Internal fork cables 13 pass through headset clamp 2 within the lumen of steerer tube 3 and into lower fork section 16 in order to connect with electronics, brakes, or lighting components of a standard bicycle wheel and hub. Lower headset bearing 4 and upper headset bearing 5 are fitted to bicycle frame 7 using standard and well understood methods.

FIGURE 4 shows a sectional side view along the steering axis. Lower headset bearing 4 and upper headset bearing 5 are fitted using standard and well understand methods to bicycle frame 7. Fork steerer tube 3 is shown rigidly fitted by a standard and well understood methods to lower fork crown 1 5 which is received by lower headset bearing 4. Lower headset bearing 4 and upper headset bearing 5 are preferably of the tapered roller or ball type that can accept both radial and thrust loadings.

Headset clamp 2 with stem fixing holes 6 is made to receive upper headset bearing 5 and cable guide wedge 12 as shown. Fork steerer tube 3 has a threaded preload hole 14 that can accept headset preload screw 12 which passes tlirougli cap 10a of cable guide wedge 10. Force from headset preload screw 12 is transferred to cable guide wedge 10 and thus through headset clamp 2 and onto upper headset bearing 5. Tightening or loosening headset preload screw 12 will allow the rider to set a preload force in order to transfer force loadings from the fork steerer tube into the bicycle frame 7. Headset clamp screws 9 are used to transfer force from headset clamp 2 into cable guide wedge 10 thus creating a rigid connection with fork steerer tube 3.

As is seen in Figure 4, a clearance exists between the upper end of the steerer tube 3 and the underside of the cap 0a of the cable guide wedge 10. Tightening of the screw 12 draws the steerer tube upward toward the cap, which also urges the headset clamp 2 downward, thus adjusting the axial pressure exerted on the upper and lower bearings 5 and 4.

Frame internal cables 1 1 are shown in a configuration such that frame internal cables 1 1 run substantially parallel with the rotation axis of fork steerer nibe 3 when passing through upper headset bearing 5. When fork steerer tube 3 is rotated about the axis of upper headset bearing 5 and lower headset bearing 4 and relative to bicycle frame 7 such as for steering the bicycle, frame internal cables 1 1 are aligned by fork steerer tube 3 and headset clamp 2 and cable guide 10 such that the frame internal cables 1 1 will be twisted longitudinally and substantially parallel to said axis of rotation.

This arrangement will avoid bending and buckling of the cables. Fork internal cables 1 3 are shown running within the lumen of fork steerer tube 3. Fork steerer tube 3 is a substantially hollow and tubular shape with a mostly round or ellipse section shape in order to rigidly receive and mate to lower headset bearing 4. Fork steerer rube 3 has a transitional shaped form between lower headset bearing 4 and upper headset bearing 5 such that it can facilitate frame internal cables 1 1 passing through upper headset bearing 5 and in a substantially parallel direction to the rotation axis of lower headset bearing 4 and upper headset bearing 5.

FIGURE 5 shows a cross section passing through upper headset bearing 5 and perpendicular to the axis of rotation of upper headset bearing 5. Fork steerer tube 3 can be seen to have a substantially "D" shaped section comprising a outer rounded portion to receive compatibly upper headset bearing 5 and a flattened section containing a central threaded preload hole ] 4. Frame internal cables 1 1 are shown passing through the upper headset bearing 5 outside (to the left as seen in the figure) of the "D" shape steerer tube 3, and fork internal cables 13 are shown passing through upper headset bearing 5 within the interior of fork steerer tube 3. FIGURE 6 shows a cross section passing through the axis of headset clamp screw 9 and perpendicular to the axis of threaded preload hole 14. As headset clamp screw 9 is tightened, cable guide wedge 10 will transfer force from headset clamp screw 9 onto the substantially flat section of fork steerer tube 3 and thus making for a rigid connection. The internal shape of headset clamp 2 can be seen to be suitable to closely receive both fork steerer tube 3 and cable guide wedge 10. Frame internal cables 1 1 and fork internal cables 13 are shown passing through upper headset bearing 5, cables 1 1 passing through the passageway defined between cable guide wedge 10 and steerer tube 3, and cables 13 passing internally through fork steerer tube 3.