FIELD AND BACKGROUND

[0001] The present invention relates particularly, but not exclusively, to a folding bicycle frame and the interaction between parts of the bicycle frame as the folding bicycle is moved from the folded position to the unfolded, riding position.

[0002] In a folding bicycle as disclosed herein, the bicycle frame itself folds in two locations about respective hinges. This enables the bicycle to fold up to a compact size. This provides significant benefits in that the compact folded bicycle is easy to transport and store.

[0003] In folding bicycles such as these, shear or twisting forces act at the abutting surface between the folding parts of the bicycle frame due to the weight exerted on the frame by a rider. These shear or twisting forces can cause a weakening of the hinge which can lead to a reduction in the structural integrity of the bicycle and subsequently a reduction in the lifetime of the bicycle.

[0004] There is therefore a desire for the structural integrity of the connection between different parts of the bicycle frame to be increased to prevent shear forces which result in a reduced strength of the joint.

[0005] The inventors have developed a novel way for increasing this structural integrity and reducing these twisting/shear forces. This in turn increases the life expectancy of the bicycle.

[0006] It will be recognised from the disclosure herein that the invention is also suitable for use in other applications.

SUMMARY

[0007] Particular aspects and embodiments are set out in the appended claims.

[0008] Viewed from a first aspect, there is provided a folding bicycle frame comprising at least one pair of hinged frame portions. Each hinge comprises a pivot on one side of the frame portions pivotally connecting the frame portions together, and a pair of opposing mating surfaces arranged to abut with each other as the frame portions pivot together. The abutting mating surfaces define a plane of contact. The opposing mating surfaces are complementary with one another and non-symmetrical about the plane of contact. The mating surfaces further comprise flanges arranged in use to receive a hinge clamp configured to secure the mating surfaces together. The hinge clamp is configured to extend around the flanges and is selectively secured thereto.

[0009] The hinged frame portions are pivotally connected together such that they are able to rotate with respect to one another. In this way, the bicycle is able to be folded into a compact shape for transportation or storage.

[0010] The term 'plane of contact' is a theoretical plane and is not necessarily intended to mean a simple plane but instead may mean the 'average' plane across which the mating surfaces come into contact with one another. For example, the mating surfaces may have protrusions which extend across this plane. Alternatively, the mating surface may be curved and curved portions of these surfaces may extend across this plane. Thus, the plane of contact may be the average plane through more complex interlocking arrangements between the mating surfaces. In this way, the opposing mating surfaces are 'non-symmetrical about the plane of contact'.

[0011] The term 'complementary' is intended to mean that the mating surfaces are inverse of each other. Specifically, where one of the mating surfaces comprises a protrusion of particular size and shape, the other mating surface comprises a recess of the same size and shape configured to receive the protrusion. When the protrusion is received in the recess, the edges of the protrusion may abut with the internal edges of the recess. This prevents the hinged portions moving with respect to one another thus limiting the stress on the hinges. In other examples, the protrusions may be slightly smaller than their respective recesses. This ensures that the recesses are able to easily receive the protrusions even if there is a build-up of grit or dirt on the mating surfaces.

[0012] The frame portions may pivot together about a median plane of the flanges, wherein the median plane may be situated equidistant from outer surfaces of the flanges. The 'median plane' is intended to mean the theoretical plane which intersects the cross section of the bicycle frame. [0013] An axis of rotation of the pivot may be coincident with the median plane.

[0014] The plane of contact may be coincident with the median plane of the flanges. In another example, the plane of contact may be offset from the median plane of the flanges. For example, the plane of contact may be above or below the median plane due to one flange being thicker than the other.

[0015] The plane of contact of the abutting mating surfaces may be parallel to an axis of rotation of the pivot. In another example, the plane of contact may be at an angle to an axis of rotation of the pivot. For example, the mating abutting surfaces may be planar and may lie at angle to the axis of rotation of the pivot. This arrangement is quick and easy to manufacture and is able to limit lateral movement of the mating surfaces with respect to one another thus limiting the stress on the hinge.

[0016] The abutting mating surfaces may be curved with respect to the plane of contact. This configuration is easy and quick to manufacture. Additionally, this provides a tolerant interaction between the concave and convex faces. For example, if there is a build-up of grit or dirt on the mating surfaces, the faces are still able to interact and lateral movement between the two prevented.

[0017] The mating surfaces are on an opposite side of the frame portion from the pivots. By having the mating surfaces at the distal side of the frame portion from the pivots, a strong closed shape is achieved. Specifically, the strength of the joint between the frame portions with the mating surfaces on the opposite side of the frame portion from the pivots enables forces to be spread efficiently across the interacting surfaces of the frame portions.

[0018] The clamp may be selectively secured to one of the hinged frame portions by a screw. This enables the clamp to be easily tightened over the flanges when assembling the bicycle from the folded position and released from the flanges when folding the bicycle.

[0019] Each mating surface may additionally comprise an indentation for receiving the screw, wherein the screw may be releasably attached to one of the mating surfaces by a screw receiving portion. By having the indentations, the screw is fully received in the mating surfaces. Thus the complementary shape of the mating surfaces are able to be held in abutment with each other. This helps to reduce the shear forces in the hinge. The screw is then usable to tighten the clamp around the mating surfaces in order to hold the two together.

[0020] One or both mating surfaces may comprise one or more protrusions that extend from a mating surface across the plane of contact towards the opposing mating surface, wherein the one or more protrusions may be configured to be received in one or more recesses on the opposing mating surface.

[0021] In this way, the interaction of the recesses and protrusions prevents the mating surfaces sliding with respect to each other. This prevents additional force being exerted onto the hinges which would reduce the structural integrity of the hinges and thus the bicycle. If the structural integrity of the hinges is reduced, this may lead to unwanted movement between the two portions of the frame. This movement may be passed to the rider and may provide an uncomfortable riding experience.

[0022] The one or more protrusions may be angular and may be configured to be received in corresponding angular recesses.

[0023] The term angular is intended to mean that the protrusions have angled ends. For example, the protrusions may be triangular when viewed in cross section or may have a saw-tooth shape.

[0024] The one or more protrusions may be convex and may be configured to be received in one or more corresponding concave recesses. This shape is seen when the recesses/protrusions are viewed in cross section. The use of curved surfaces such as these are beneficial in that, when paint is applied, the paint is less likely to chip leading to movement between the parts and the ingress of unwanted moisture is therefore prevented.

[0025] The one or more protrusions may be square and/or rectangular and may be configured to be received in one or more corresponding square and/or rectangular recesses. This shape combination of protrusions/recesses is beneficial when a low clamping force is provided by the clamp (for example if the screw is not done up tightly enough). Even if the clamping force is low, due to the straight sides of the recesses/protrusions, it is difficult for the protrusions to ride up out of the recesses when a twisting force is applied to the frame during use.

[0026] In a further example, a combination of the above described recess/protrusion shapes may be used.

[0027] The abutting mating surfaces may form less than about 60% of a total cross sectional area of the frame portions. For example, the mating surfaces may form about 30% of the total cross sectional area of the frame portions. Thus, this ensures there is a sufficient area on the outer surface of the flange of the mating surfaces for the clamp to abut with to secure the mating surfaces together. [0028] The folding bicycle frame may comprise two pairs of hinged frame portions. In this way, the bicycle is able to be folded into a compact state easy for transportation and storage.

[0029] The at least one pair of hinged frame portions may be located in a top tube of the folding bicycle frame. Thus, the top tube can be folded to reduce the footprint of the bicycle. A large amount of force is exerted through the top tube due to the riders weight. Thus, the use of the hinged frame portions with the complementary, non-symmetric mating surfaces limits shear forces between the mating surfaces and increases the structural integrity of the bicycle.

[0030] The at least one pair of hinged frame portions may be located in a handlebar stem of the folding bicycle frame. Thus, the handlebars can be folded away when the bicycle is folded. A large amount of force may be exerted through the handlebar stem due to the riders weight through the handlebars. Thus, the use of the hinged frame portions with the complementary, non-symmetric mating surfaces limits shear forces between the mating surfaces and increases the structural integrity of the bicycle.

[0031] Viewed from a further aspect, there is provided a folding bicycle frame comprising at least one pair of hinged frame portions. Each hinge comprises a pivot on one side of the frame portions pivotally connecting the frame portions together, and a pair of opposing mating surfaces arranged to abut with each other as the frame portions pivot together. The abutted mating surfaces define a plane of contact. One or both mating surfaces comprise one or more protrusions that extend from a mating surface across the plane of contact towards the opposing mating surface. The one or more protrusions are configured to be received in one or more recesses on the opposing mating surface. The mating surfaces further comprises flanges arranged in use to receive a hinge clamp configured to secure the mating surfaces together. The hinge clamp is configured to extend around the flanges and is selectively secured thereto.

[0032] In this way, the interaction of the recesses and protrusions prevents the mating surfaces sliding with respect to each other. This prevents additional force being exerted onto the hinges which would reduce the structural integrity of the hinges and thus the bicycle.

[0033] All alternatives and variations discussed above with respect to the first aspect are applicable with respect to the folding bicycle frame of the second aspect.

[0034] Other aspects will also become apparent upon review of the present disclosure, in particular upon review of the Brief Description of the Drawings, Detailed Description and Claims sections. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Examples of the disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:

[0036] Figure 1A shows the folding bicycle in an unfolded configuration;

[0037] Figure IB shows the folding bicycle in a folded configuration;

[0038] Figure 2A shows a zoomed in portion of the hinged frame portions of the invention with the folding bicycle in an unfolded configuration;

[0039] Figure 2B shows a zoomed in portion of the hinged frame portions of the invention with the folding bicycle in a folded configuration;

[0040] Figure 3A shows a zoomed in portion of a pair of hinged frame portions of the invention in the top tube with the folding bicycle in an unfolded configuration;

[0041] Figure 3B shows a zoomed in portion of a pair of hinged frame portions of the invention in the top tube with the folding bicycle in a folded configuration;

[0042] Figure 4A shows a zoomed in portion of a pair of hinged frame portions of the invention in the handlebar stem with the folding bicycle in an unfolded configuration;

[0043] Figure 4B shows a zoomed in portion of a pair of hinged frame portions of the invention in the handlebar stem with the folding bicycle in a folded configuration;

[0044] Figure 5A shows a schematic view of the hinged part of the bicycle frame of the present invention with the clamp and screw;

[0045] Figure 5B shows a schematic view of the hinged part of the bicycle frame of the present invention with the clamp and screw and with the theoretical median plane of the flanges;

[0046] Figures 6A and 6B show a schematic view of an alternative arrangement for the mating surfaces according to the present invention;

[0047] Figures 7A and 7B show a schematic view of an alternative arrangement for the mating surfaces according to the present invention;

[0048] Figures 8A and 8B show a schematic view of an alternative arrangement for the mating surfaces according to the present invention; [0049] Figures 9A and 9B show a schematic view of an alternative arrangement for the mating surfaces according to the present invention;

[0050] Figures 10A and 10B show a schematic view of an alternative arrangement for the mating surfaces according to the present invention;

[0051] Figures 11A and 11B show a schematic view of an alternative arrangement for the mating surfaces according to the present invention;

[0052] Figures 12A and 12B show a schematic view of an alternative arrangement for the mating surfaces according to the present invention;

[0053] Figures 13A and 13B show a schematic view of an alternative arrangement for the mating surfaces according to the present invention;

[0054] Figures 14A and 14B show a schematic view of an alternative arrangement for the mating surfaces according to the present invention; and

[0055] Figures 15A and 15B show a schematic view of an alternative arrangement for the mating surfaces according to the present invention.

[0056] While the disclosure is susceptible to various modifications and alternative forms, specific example approaches are shown by way of example in the drawings and are herein described in detail. It should be understood however that the drawings and detailed description attached hereto are not intended to limit the disclosure to the particular form disclosed but rather the disclosure is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the claimed invention.

[0057] As used in this specification, the words "comprises", "comprising", and similar words, are not to be interpreted in an exclusive or exhaustive sense. In other words, they are intended to mean "including, but not limited to".

[0058] It will be recognised that the features of the above-described examples of the disclosure can conveniently and interchangeably be used in any suitable combination. It will also be recognised that the invention covers not only individual embodiments but also combinations of the embodiments that have been discussed herein. DETAILED DESCRIPTION

[0059] The present teaching relates generally to a frame of a folding bicycle and a means for securely joining parts of the bicycle frame together as it moves from the folded to the unfolded position.

[0060] Figure 1A shows the folding bicycle frame 1 of the present invention in a folding bicycle in an unfolded, riding position. As can be seen from this figure, there are two pairs hinged frame portions 2, 3. These will be discussed further later. One of these is located on a top tube 4 of the bicycle and the other on a handlebar stem 22.

[0061] Figure IB shows the folding bicycle of the present invention in a fully folded position. As is shown in this figure, the bicycle is folded at the two pairs of hinged frame portions 2 and 3.

[0062] Figures 2A and 2B show zoomed in portions of the pairs of hinged frame portions 2, 3 of the folding bicycle according to the present example in the unfolded and folded arrangement respectively. These are described in more detail with respect to figures 3A to 3B and 4A to 4B.

[0063] Figure 3A shows one of the pairs of hinged frame portions 2 on the top tube 4 of the folding bicycle. The pair of hinged frame portions 2 comprises two portions of the bicycle frame 5, 6 each comprising a hinge portion with a pivot 7, 8. The pivots 7, 8 pivotally connect the frame portions 5, 6 together. As can be seen from this figure, the frame portions 5, 6 are pivotally connected on one side of the frame. On the opposing side of the frame, each frame portion 5, 6 comprises a mating surface 9, 10. When the frame portions are in the unfolded arrangement as is shown in this figure, the mating surface 9 inside the frame portion 5 is configured to abut with the mating surface 10 inside the frame portion 6.

[0064] The mating surfaces 9, 10 comprise flanges 11, 12 extending laterally from their respective frame portions 5, 6. When the frame portions 5, 6 are pivoted into the unfolded position, they are secured in place by a clamp 13. The clamp is tightened over the outer surfaces of the flanges 11, 12 by tightening a screw (not shown in this figure) using a handle 14. When the handle 14 is rotated in a first direction, the screw moves into the frame portions and the clamp 13 is forced downwards such that inner surfaces of the clamp exert a force on outer surfaces of the flanges 11, 12. This holds the mating surfaces 9, 10 in abutment. When the handle 14 is rotated in a second direction, opposite the first direction, the screw moves out of the frame portions and the clamp is released from the outer surfaces of the flanges.

[0065] The mating surface 10 additionally comprises protrusions 15 (only one visible in this picture). These protrusions are received by recesses 16 (only one visible in this picture) of the same size and shape in mating surface 9. Thus, the mating surfaces 9, 10 have a complementary shape. There is a plane of contact between the two mating surfaces. When the mating surfaces are brought into abutment with each other, the mating surfaces, due to the protrusions 15 and recesses 16, are non-symmetrical about this plane of contact. The protrusions 15 extend across the plane of contact to be received by the recesses 16.

[0066] Although the protrusions 15 are shown as being formed in mating surface 10 and recesses in mating surface 9, the protrusions 15 may instead be formed in mating surface 9 and recesses in mating surface 10. Alternatively, each mating surface 9, 10 may comprise a protrusion 15 and a recess 16 to be received by a corresponding protrusion 15 and recess 16.

[0067] Figure 3B shows the pair of hinged frame portions of figure 3A in a folded, open position. The mating surface 9, flange 11 and recesses 16 are not visible in this figure.

[0068] The clamp 13 is attached to one of the frame portions 5, 6 by a screw screwed into a screw receiving portion 17. Each mating surface comprises an indentation 18 for receiving the screw and the screw receiving portion 17. As shown in figure 3B, the screw receiving portion 17 is attached to the frame portion 5. In other examples, the screw receiving portion 17 may be attached to the frame portion 6.

[0069] The protrusions 15 are shown on the mating surface 10. As can be seen from this figure, each protrusion 15 extends from the side of the flange the mating surface 10. The end of the protrusion 15 distal from the side of the mating surface 10 stops before indentation 18. In some examples, the protrusions may not extend to the edge of the mating surface but may stop before the edge of the mating surface. In this way, when the frame portions are in the unfolded closed position, the protrusions/recesses would not be visible from the side (as in figure 3A). The recess 16, although not shown in this figure, has a complementary shape. In this way, when the frame portions are pivoted into the closed position (as is shown in figure 3A), the protrusions 15 are fully received in recesses 16 in the opposing mating surface. The distal end of the protrusion 15 abuts against a distal end of the recess 16. This abutment limits shear forces between the two mating surfaces and thus shear forces on the hinge. Although two protrusions 15 are shown in this figure, more or fewer than this may be used (to interact with a corresponding number of recesses 16).

[0070] Figures 4A and 4B show the other pair of hinged frame portions 3 on the handlebar stem 22 of the folding bicycle. The hinged frame portions 3 are shown in the unfolded or closed position in figure 4A and the folded or open position in figure 4B. The pair of hinged frame portions 2 comprises two portions of the bicycle frame 19, 20. Other features which correspond to those in figures 3A and 3B are labelled with the same reference numerals.

[0071] The screw 21 is visible in figure 4B, extending through the screw receiving portion 17 and located in the indentation 18 in mating surface 9. When the frame portions 19, 20 are pivoted into the closed position (as shown in figure 4A), the screw is also received in the indentation 18 in mating surface 10. This enables the mating surfaces 9, 10 to abut without the screw or screw receiving portion preventing this happening. Also visible in figure 4B is both recesses 16 in mating surface 9. As can be seen in from this figure, the recesses 16 extend from the sides of the mating surface 9 and stop before reaching the indentation 18. As with the configuration of figures 3A and 3B, in some examples, the protrusions may not extend to the edge of the mating surface but may stop before the edge of the mating surface. Although not visible in figure 3B, the recesses 16 in the mating surface 9 in the pair of hinged frame portions 2 in the top tube 4 of figures 3A and 3B are the same as shown in figure 4B.

[0072] Although the mating surfaces 9 and 10 are shown in figures 2 to 4 as comprising a protrusion and complementary recess extending from the side of the mating surface, a number of alternative mating surfaces could be used as will now be discussed.

[0073] Figures 5A shows a schematic isometric view of the hinged part of the frame portions. This figure is shown for reference. The mating surfaces 9, 10 shown in this figure are planar. Figure 5B is the same as figure 5A but additionally shows the axis of rotation 23 and a theoretical median plane 24 of the flanges. In this example, the median plane 24 is equidistant between the outer edges of the flanges 11, 12.

[0074] Figures 6A and 6B to 15A and 15B show isometric and end on schematic views respectively of alternative examples of the mating surfaces 9, 10.

[0075] In figures 6A and 6B, protrusions 15 are formed in mating surface 10 and extend across the plane of contact. Unlike the protrusions shown in figures 2 to 4, the protrusions 15 extend from the end of the flange 12 along the mating surface rather than from the side. Recesses 16 are formed in mating surface 9 to receive the protrusions 15. When viewed end on as in figure 6B, the protrusions/recesses are rectangular. In another example, the protrusions/recesses may be square when viewed end on as in figure 6B.

[0076] The protrusions 15 and recesses 16 shown in figures 7A and 7B are the same as those in figures 6A and 6B except, when viewed in cross section, they have a semi-circular shape. Thus, in this example, the protrusions 15 have a convex shape and the recesses 16 have a concave shape in order to receive these protrusions 15.

[0077] The protrusions 15 and recesses 16 shown in figures 8A and 8B are the same as those in figures 6A and 6B except, when viewed in cross section, they have an angular and more specifically a triangular shape. Thus, in this example, the protrusions 15 have an angular shape and the recesses 16 have an angular shape in order to receive these protrusions 15. In another example, the protrusions 15 may have a saw tooth shape when viewed in cross section.

[0078] Although each of figures 6 to 8 show a single protrusion 15 and recess 16 on either side of the indentation 18, there may be more than this. For example, there may be two or more protrusions and recesses on either side of the indentation 18. Additionally or alternatively, rather than the protrusions 15 both being formed on one mating surface 10 and recesses 16 both being formed on the other mating surface 9, each mating surface may comprise both a recess and a protrusion to couple with a recess and a protrusion on an opposing mating surface.

[0079] Figures 9A and 9B show an alternative example of the mating surfaces. Instead of individual protrusions and recesses spaced from one another, the mating surfaces of this example have a plurality of adjacent recesses and protrusions. As can be seen in this figure, the recesses/protrusions are angular in shape. In another example, a similar arrangement could be used with curved (i.e. concave/convex) recesses/protrusions or with square/rectangular recesses/protrusions.

[0080] Although figures 6 to 9 show the protrusions/recesses as being visible from the end of the mating surfaces, this may not be the case. Instead, the protrusions/recesses may be formed in the mating surfaces and may not extend from the ends of the mating surface. Thus when the hinged portions are in the closed position, the recesses/protrusions may not be visible from the end on view of the flanges. All protrusions/recesses shown in figures 6 to 9 may extend to the distal end of the mating surfaces adjacent the internal area of the frame portion from the end shown in figures 6B to 9B, i.e. along the entire length of the flanges. Alternatively, the protrusions/recesses may extend partially along the mating surfaces towards the internal area of the frame portion.

[0081] Figures 10A and 10B show an alternative example of the mating surfaces 9, 10. The mating surfaces 9, 10 are at an angle to the median plane 24. Specifically, when viewed end on as in figure 10B, the mating surfaces may be formed in a 'V' shape. Thus, one of the mating surfaces extends across the plane of contact to receive the angled mating surface of the other hinged frame portion. [0082] Figures llA and 11B show an alternative example of the mating surfaces similar to those in figures 10A and 10B. Instead of planar mating surfaces, the mating surfaces 9, 10 are curved.

[0083] Figures 12A and 12B show an alternative example of the mating surfaces. The mating surfaces 9, 10 in this example are curved as in figure 11. The flange 11 has a reduced width compared to flange 12 and is fully received within flange 12. This can be seen in figure 12B. Thus the sides of flange 11 are not visible when the hinged portions are viewed in cross section.

[0084] Figures 13A and 13B show an alternative example of the mating surfaces. This corresponds to figure 12 but the mating surfaces are planar and angled with respect to the median plane rather than curved.

[0085] Figures 14A and 14B show an alternative example of the mating surfaces. As with figures 11 and 12, the flange 11 has a reduced width compared to flange 12. The mating surfaces 9, 10 are substantially planar and coincident with the plane of contact. Portions of the flange 12 extend around the sides of flange 11 across the plane of contact such that flange 11 is fully received in flange 12.

[0086] Figures 15A and 15B show an alternative example of the mating surfaces. The mating surfaces 9, 10 in this example meet at an angle to the median plane and axis of rotation. A first side of one of the mating surfaces extends above the plane of contact and a second side of the other mating surface extends below the plane of contact.

[0087] The various embodiments described herein are presented only to assist in understanding and teaching the claimed features. These embodiments are provided as a representative sample of embodiments only, and are not exhaustive and/or exclusive. It is to be understood that advantages, embodiments, examples, functions, features, structures, and/or other aspects described herein are not to be considered limitations on the scope of the invention as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilised and modifications may be made without departing from the spirit and scope of the claimed invention. Various embodiments of the invention may suitably comprise, consist of, or consist essentially of, appropriate combinations of the disclosed elements, components, features, parts, steps, means, etc., other than those specifically described herein. In addition, this disclosure may include other inventions not presently claimed, but which may be claimed in future.