GB2401590A

GB2401590A - Folding bicycle

Info

Publication number: GB2401590A
Application number: GB0311340A
Authority: GB
Inventors: Jon Frank Ross Whyte
Original assignee: ATB Sales Ltd
Current assignee: ATB Sales Ltd
Priority date: 2003-05-16
Filing date: 2003-05-16
Publication date: 2004-11-17
Anticipated expiration: 2023-05-16
Also published as: GB0311340D0; GB2401590B

Abstract

The bicycle includes a steering assembly (21) including forks (25) and a front wheel carrier (28) pivotably connected with the assembly by way of a hinge and carrying a front wheel (26). The carrier (28) is pivotable between a use position in which the wheel (26) is releasably fixed by its axle (26) to the forks (25) and a folded position in which the axle is spaced from the assembly in direction towards the back of the bicycle, the wheel (26) being then disposed to partly overlie a main frame member (11) of the bicycle. Movement of the carrier (28) into the folded position can be initiated by reversing the steering assembly. The carrier (28) is a frame in which one of its members (29) additionally functions as a front mudguard.

Description

FOLDING BICYCLE

The present invention relates to a folding bicycle.

Folding bicycles are in widespread use in urban and other environments in circumstances where folding into more compact dimensions is of advantage to assist storage in buildings or for convenience in other forms of transport, such as rail carriages and motor vehicles.

To be successful, such a bicycle has to not only be capable of folding into a small size for convenient carrying and storage, but also has to have a stiff and lightweight structure so that it rides in much the same way as a normal bicycle.

The positions of the three points of contact with the rider, i.e. saddle, pedals and handlebars, cannot be significantly altered from a standard bicycle without an adverse effect on ride, efficiency of use and rider comfort. Thus, the number and disposition of fold points is critical to a satisfactory design. For example, the greater the number of fold points the smaller the achievable fold package, but the less the rigidity in the unfolded, use state and the greater the overall weight. In addition, many existing designs require the use of non-standard basic components, such as wheel hubs and gearing systems, which increase production costs and prevent later mixing and matching of parts.

It is therefore the principal object of the present invention to provide a folding bicycle which can be folded at the front end in a compact manner, but retains a lightweight and stiff structure at this end in the unfolded or use state.

A subsidiary object of the invention is to provide a folding bicycle with a front construction which, notwithstanding inclusion of a folding system, permits utilization of selected standard components, for example front wheel and hub.

According to the present invention there is provided a folding bicycle including a steering assembly and a wheel carrier pivotably connected with the assembly and carrying a front wheel, the carrier being movable between a use position in which the wheel is releasably fixed at the axis of rotation thereof to the assembly and a folded position in which the wheel axis is spaced from the assembly in direction towards the back of the bicycle.

In the case of such a bicycle front end arrangement, folding of the front wheel is achieved without the need for a fold location within the main structure of the steering assembly itself, such an assembly conventionally consisting of a post which carries handlebars at the top and separates into front wheel forks embracing the front wheel. The post and forks can remain as a non-foldable, and therefore structurally rigid, unit in the same manner as a standard bicycle, since the task of front wheel folding is assigned to a wheel carrier foldable - together with the front wheel it carries - relative to the assembly. In the unfolded or use state the front wheel is fixed at its axis of rotation to the steering assembly so that, regardless of the interpositioning of the carrier, a direct attachment of wheel and assembly is provided to ensure optimum stiffness.

Preferably, the wheel carrier is pivotably connected with the steering assembly in the region of the circumference of the wheel and in addition is detachably connected with the assembly in the region of the wheel axis. The point of pivotal interconnection of carrier and assembly can thus be located close to, but outside the wheel perimeter. Moreover, not only the wheel, but also the carrier can be releasably fixed to the assembly at the wheel axis.

The detachable connection of the carrier and assembly is preferably carried out by way of an axle of the wheel, for which purpose the axle can comprise a shaft provided at each end thereof with an extension element secured to the carrier and detachably connected with the assembly. The shaft can therefore be a standard part of a front wheel hub which is adapted to the requirements of a bicycle embodying the present invention by the fitting of an extension element of appropriate design on each end of the shaft. Each such extension element can comprise an axially inner portion secured to the carrier and an axially outer portion which defines a stub axle and provides the detachable connection with the assembly.

The axle is preferably releasably fixed to, and the carrier thereby also detachably connected with, the assembly by way of quick-action fastening means, which can be of a conventional kind, for example a quick-release clamping mechanism extending through the axle and co-operable with the assembly. Such a mechanism can have the form of an over-centre, leveraction clamp coupled to a spindle passing through the axle or can be any other suitable quick-release device. The axle itself is, for preference, removably located in open-ended slots of the assembly, in particular at the free ends of wheel forks of the assembly. Accidental release of the axle from the slots in the event of inadequate tightening of the quickaction fastening means can be prevented by provision of an openable safety catch closing one of the slots. In that case, the catch is preferably resiliently biased into a position closing the slot. Additional security in retention of the axle can be provided if the catch comprises a locating lever having a recess receiving and locating the axle.

With advantage, the quick-release clamping mechanism can also be employed, in the folded position of the carrier, to lock the carrier inclusive of front wheel in that position. For example, the mechanism can be operated to couple with coupling means at the bicycle, preferably a coupling point on a rear wheel assembly of the bicycle when that assembly is similarly in a folded position.

The carrier is preferably pivotably connected with the assembly by a hinge, which can be disposed in the region of a division in the assembly to form wheel forks. Additional saving of space in the folded state of the front end of the bicycle may be able to be achieved if the carrier is so pivotably connected with the assembly that the carrier is movable from the use position to the folded position only after rotation of the assembly through substantially half a revolution. In that case, any forward offset of, for example, the wheel forks of the assembly in the use state thereof can be used to advantage by turning the assembly to, in effect, reverse the direction of offset, whereby the front wheel is displaced rearwardly thus shortening the length of the bicycle - even before the carrier is moved into the folded position.

For preference, the frame comprises a main member extending substantially in the fore and aft direction of the bicycle and the wheel in the folded position of the carrier is disposed partly alongside the member in side elevation of the bicycle. This results in a particularly compact format of the unit of assembly and carrier, inclusive of wheel, in the folded position, in which a significant reduction in both the length and the depth of the bicycle in folded state is achieved with only a small penalty of increase in width.

The carrier itself conveniently has the form of a frame, in which case a member of the frame can form a mudguard of the front wheel. Conventionally, front wheel mudguards are comparatively flexible components and do not play any part in the structural rigidity of the bicycle. In the present case, however, a structural role is assumed by the mudguard, which is suitably constructed to perform this task, for example as an inherently stiff metal pressing. The frame preferably also comprises two further frame members each extending from the region of a respective end of the mudguard to the region of the wheel axis, thus imparting an approximately triangular shape to the frame in side elevation of the bicycle. Each of the further frame members can comprise two stays extending parallel to each other on either side of the wheel so as to enhance the overall rigidity of the frame.

As a further feature contributing to the objective of a compact folded state the steering assembly can comprise a steering post and handlebars pivotably connected to the post to be movable between a use position in which the assembly can be controlled by means of the handlebars and a folded position in which the handlebars are disposed alongside the front wheel in its folded position. In that case, the handlebars in the folded position can partly overlie the front wheel.

A preferred embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a schematic side elevation of a bicycle embodying the invention; Fig. 2 is a schematic side elevation, to an enlarged scale, of the front part of the bicycle of Fig. 1 with a steering assembly, front wheel carrier and front wheel thereof turned into a position for folding; Fig. 2A is a detail view, from the front of the bicycle, of a front wheel axle and carrier fastening mechanism of the assembly; Fig. 3 is a view similar to Fig. 2, but showing the carrier and wheel in folded position; and Fig. 4 is a view similar to Fig. 3, but additionally showing handlebars of the steering assembly in folded position.

Referring now to the drawings, there is shown in Fig. 1 a folding bicycle comprising a frame 10 having as basic elements a relatively deep main member 11 extending in the fore-and-aft direction of the bicycle, a down tube 12 extending downwardly from the main member at a location slightly behind the midpoint of its length and a seat tube 13 secured to and extending between the rearward end of the main member and the lowermost end of the down tube. A foldable rear wheel assembly 14, inclusive of a rear wheel 15, is connected with the seat tube 13, which receives a retractible seat post 16 carrying a seat 17. A drive sprocket of a chain-and-sprocket drive system 18 operated by pedal cranks with foot pedals is arranged in the vicinity of the junction of the down tube 12 and seat tube 13 and serves to drive the rear wheel 15 by way of a further sprocket and a chain coupling the sprockets. The seat post 16 can be retracted into the seat tube 13 and the rear wheel assembly 15 folded to lie against the frame 10 to reduce the size of the bicycle in these regions. These aspects of folding of the bicycle do not concern the present invention and accordingly are not discussed in further detail.

The main member 11, which can be a fabricated hollow aluminium body, carries at its forward end a head tube 19 in which a steering post 20 of a steering assembly 21 is rotatably mounted. Handlebars 22 of the steering assembly are fastened to the steering post 20 above the head tube 19 and are pivotable relative to the post into a folded position in which they partly overlie the frame member 11, as described further below. The handlebars 22 comprise a suitably shaped handlebar member 23 attached to the steering post 20 by way of a connecting arm 24 which is directed forwardly of the bicycle to gain additional spacing of the handlebar member 23 from the seat 17. Pivotation of the handlebars 22 is provided by way of a pivot connection of the handlebar member 23 to the arm 24.

Below the head tube 19 the steering assembly 21 divides into front wheel forks 25, which are detachably connected at the lower ends thereof with an axle 26 of a front wheel 27.

The wheel 27 is carried by a carrier 28 which is pivotably connected with, but otherwise constitutes a component constructionally separate from, the steering assembly 21. This feature distinguishes the bicycle from conventional folding bicycles in which folding of the front wheel is generally achieved by provision of a fold point within the steering assembly itself, particularly at the junction of the steering post and forks. This significantly detracts from the overall rigidity of the assembly to the detriment of both ride and travel comfort. I The carrier 28 has the form of a frame composed of an arcuate frame member 29 also functioning as a mudguard for the front wheel 27 and two further frame members 30 each extending from the region of a respective end of the arcuate frame member 29 to the region of the axle 26 of the wheel 27. Each further frame member 30 consists of two stays disposed one on each side of the wheel. Unlike conventional bicycles, whether folding or I nonfolding, the front mudguard is a structurally rigid member so that it can serve as part of the frame and thus accept loads imposed on the carrier.

The carrier 28 is pivotably connected with the steering assembly 21 by way of a hinge 31 disposed in the vicinity of the junction of the steering post 20 and front wheel forks 25 and in addition is detachably connected with the assembly at the free ends of the forks by way of the axle 26 of the front wheel 27. The axle 26 thus serves to detachably connect both the wheel 27 and the carrier 28 to the lower ends of the forks. For this purpose the axle 26 comprises a tubular axle shaft 32 of conventional form carrying a hub of the front wheel by way of bearings integrated in the hub, the shaft 32 being additionally provided at each end with a stepped extension sleeve 33 having an axially inner portion 33a on which the stays - at an associated side of the wheel - of the two frame members 30 are mounted and an axially outer portion 33b defining a stub axle engageable in an open-ended slot 34 at the free end of an associated one of the forks 25. The axle 26, and thus the wheel 27 and carrier 28, are detachably connected with the forks 25 by a quick-release clamping mechanism 35 in the form of a pin 36 extending through the axle shaft 32 and provided at one end with a fixed head 36a and at the other end with an over-centre, lever-actuated eccentric 36b co-operable with an adjoining pressure surface of one of the arms of the forks to clamp the axle in the slots 34. On actuation of the clamping mechanism 35 to relieve the clamping pressure the axle 26 together with the wheel 27 and carrier 28 can be slid out of the slots 34 under pivotation of the carrier at the hinge 31, whereby the wheel, supported by the carrier, is then freely pendulating at the steering assembly.

In order to safeguard against unintended detaching of the axle 26 from the front forks 25 in the case of, for example, insufficient tightening of the clamping mechanism 35, an openable safety catch 37 is arranged at one of the fork arms to close the associated slot 34 when the axle is located therein. The safety catch 37 comprises a spring-loaded locating lever 37a which is biased into a closing position and has an arcuate recess receiving and thereby positively locating the axle. The lever 37a is pivotable into an open position allowing removal of the axle 26 from the slots 34 when the clamping mechanism is released.

As evident from the drawings, the hinge 31 allows pivotation of the unit of wheel 27 and carrier 28 after the axle 26 has been released from the slots 34. The intended folded position of this unit is achieved by turning the steering assembly 21 through approximately 180 so that pivotation of the unit is in direction towards the rear of the bicycle and the wheel 27 is brought into a position in which it partly overlies the main member 11 of the frame. As shown in Fig. 3, this results in a substantial reduction in the size of the front of the bicycle in relation to the use position of the unit. A stud 38, which is at the trailing end of the arcuate frame member 29 or mudguard and which in the folded position of the unit is redisposed to form the lowermost point of the unit, functions as a ground rest.

Finally, folding of the front part of the bicycle is completed by pivotation of the handlebar member 23 relative to the connecting arm 24 by way of the afore-mentioned pivot connection to also bring the member 23 into a position partly overlying the main frame member 11, as depicted in Fig. 4. The front part of the bicycle has thus assumed a compact form compatible with the requirements of ease of transport and storage.

Return of the handlebars 22 and unit of front wheel 27 and carrier 28 to the position of use is accomplished by reversal of the sequence of folding. With the carrier 28 returned to the position of use, the axle 26 is again received in the slots 34 and the quick-release clamping mechanism 35 is reapplied, by way of its lever-actuated eccentric, to fix the axle in the slots. A rigid reconnection of the carrier 28 inclusive of wheel 27 to the steering assembly 21 is thereby achieved. The safety catch 36 provides an additional safeguard against the consequences of improper tightening of the clamping mechanism 35.

In the folded state of the front wheel 27, this can be positioned to lie at a side of the frame opposite that against which the folded rear wheel lies. The two wheels can, in the folded state, thus be disposed almost in axial alignment, whereby the folded bicycle represents a particularly space-saving package. The bicycle can be conveniently retained in its compactly folded state by operation of the quick-release clamping mechanism 35 to couple with a suitable coupling point (not shown) provided on the rear wheel assembly 14. Quite apart from attainment of these favourable minimum dimensions, in normal use the bicycle exhibits, at the front, a solidity and structural integrity of the steering assembly and front wheel comparable with that of normal bicycles, that is to say without compromising ride and handling behaviour due to inclusion of a hinge point for folding.

Claims

1. A folding bicycle including a steering assembly and a wheel carrier pivotably connected with the assembly and carrying a front wheel, the carrier being movable between a use position in which the wheel is releasably fixed at the axis of rotation thereof to the assembly and a folded position in which the wheel axis is spaced from the assembly in direction towards the back of the bicycle.

2. A bicycle as claimed in claim 1, wherein the carrier is pivotably connected with the assembly in the region of the circumference of the wheel and in addition is detachably connected with the assembly in the region of the wheel axis.

3. A bicycle as claimed in claim 2, wherein the carrier is detachably connected with the assembly by way of an axle of the wheel.

4. A bicycle as claimed in claim 3, wherein the axle comprises a shaft provided at each end thereof with an extension element secured to the carrier and detachably connected with the assembly.

5. A bicycle as claimed in claim 4, wherein the extension element at each end of the axle comprises an axially inner portion secured to the carrier and an axially outer portion defining an axle stub and detachably connected with the assembly.

6. A bicycle as claimed in any one of claims 3 to 5, comprising quickaction fastening means for releasably fixing the axle and also the assembly to thereby detachably connect the carrier with the assembly.

7. A bicycle as claimed in claim 6, wherein the quick-action fastening means comprises a quick-release clamping mechanism extending through the axle and co- operable with the assembly.

8. A bicycle as claimed in claim 7, wherein the clamping mechanism is operable to couple with coupling means at the bicycle to lock the carrier in the folded position.

9. A bicycle as claimed in any one of claims 3 to 8, wherein the axle is removably located in open-ended slots of the assembly.

10. A bicycle as claimed in claim 9, wherein the slots are disposed at the free ends of wheel forks of the assembly.

11. A bicycle as claimed in claim 9 or claim 10, comprising an openable safety catch closing one of the slots.

12. A bicycle as claimed in claim 11, wherein the catch is resiliently biased into a position closing the associated slot.

13. A bicycle as claimed in claim 12, wherein the catch comprises a locating lever having a recess receiving and locating the axle.

14. A bicycle as claimed in any one of the preceding claims, wherein the carrier is pivotably connected with the assembly by a hinge.

15. A bicycle as claimed in claim 14, wherein the hinge is disposed in the region of a division in the assembly to form wheel forks.

16. A bicycle as claimed in any one of the preceding claims, wherein the carrier is so pivotably connected with the assembly that the carrier is movable from the use position to the folded position only after rotation of the assembly through substantially half a revolution.

17. A bicycle as claimed in any one of the preceding claims, wherein the frame comprises a main member extending substantially in the fore and aft direction of the bicycle and the wheel in the folded position is disposed partly alongside the member in side elevation of the bicycle.

18. A bicycle as claimed in any one of the preceding claims, wherein the carrier has the form of a frame.

19. A bicycle as claimed in claim 18, wherein the frame comprises a frame member forming a mudguard of the front wheel.

20. A bicycle as claimed in claim 19, wherein the frame comprises two further frame members each extending from the region of a respective end of the mudguard to the region of the wheel axis.

21. A bicycle as claimed in claim 20, wherein each of the further frame members comprises two stays extending parallel to each other on either side of the wheel.

22. A bicycle as ctaim,ed in a,,y one of the preceding claims, wherein the stee,ing assembly comprises a steering pest and handlebars pivotable relative to the post to be movable between a use position in which the assembly can be controlled by means of the handlebars and a folded position in which the handlebars are disposed alongside the front wheel in its folded position.

22. A bicycle as claimed in any one of the preceding claims, wherein the steering assembly comprises a steering post and handlebars pivotable relative to the post to be movable between a use position in which the assembly can be controlled by means of the handlebars and a folded position in which the handlebars are disposed alongside the front wheel in its folded position.

Amendments to the claims have been filed as follows 1. A folding bicycle including a steering assembly and a wheel carrier pivotably connected with the assembly and carrying a front wheel, the carrier being movable between a use position in whicn the wheel is reieasably fixed at the axis of rotation thereof to the assembly and a folded position in which the wheel axis is spaced from the assembly in direction towards the back of the bicycle.

2. A bicycle as claimed in claim 1, wherein the carrier is pivotabiy connected with the assembly in the region of the circumference of the wheel and in addition is detachably connected with the assembly in the region of the wheel axis.

4. A bicycle as claimed in claim 3, wherein the axle comprises a shaft provided at each end thereof with an extension element secured to the carrier and detachably connected vrith the assembly.

5. A bicycle as claimed in claim 4, wherein the extension element at each end of the axle co,,,p,ises an sx,a,y inner potion secured to the ca,,ie, and an axially outer potion defining an axle stub and detachably connected with the assembly.

6. A bicycle as claimed in any one of claims 3 to 5, comprising quickaction fastening means for releasably fixing the axle and also the assembly to thereby detachably connect I the carrier with the assembly.

8. A bicycle as claimed in claim 7, wherein the bicycle comprises coupling means and the clamping mechanism is operable to couple with the coupling means to lock the carrier in the folded position.

10. A bicycle as claimed in claim 9, wherein the slots are disposed at the free ends of wheel forks of the assembly. ! 11. A bicycle as claimed in claim 9 or claim 10, comprising an openable safety catch closing one of the slots.

1. A bicycle as c!airned in an,, one of the preceding c!ai.rns, wherein the carrier is so pivotably connected with the assembly that the carrier is movable from the use position to the folded position only after rotation of the assembly through substantially half a revolution.

17. A bicycle as claimed in any one of the preceding claims, wherein the bicycle comprises a frame having a main member extending substantially in the fore and aft direction of the bicycle and part of the wheel in the folded position of the carrier is disposed; alongside the member in side elevation of the bicycle.

19. A bicycle as claimed in claim 18, wherein the frame of the carrier comprises a frame member forming a mudguard of the front wheel. i i

20. A bicycle as claimed in claim 19, wherein the frame of the carrier comprises two further frame membe,s each extending from the region of a respective arid of the mudguard to the region of the wheel axis.

21. A bicycle as claimed in cisim 20, wherein each of the further frame members comprises two stays extending parallel to each Other on either side of the wheel.