WO2005092696A1

WO2005092696A1 - Folding cycle

Info

Publication number: WO2005092696A1
Application number: PCT/EP2005/003082
Authority: WO
Inventors: Mark Andrew Sanders
Original assignee: Mas Design Products Limited
Priority date: 2004-03-27
Filing date: 2005-03-23
Publication date: 2005-10-06
Also published as: GB2412354A; GB0406964D0; CN100478246C; CN1997545A

Abstract

There is provided a frame assembly for a foldable cycle (110; 510) comprising a rear frame portion (120; 220; 520) including a mounting (122) for a rear wheel (123); a forward frame portion (130;230;530), hingedly connecting to the rear frame portion (120; 220; 520) such that the two are foldable towards each other; and hingedly connecting to the forward frame portion (130; 230; 530), a pivot assembly (132:232; 532) for a mounting arm (140; 240) including a mounting (142)for a forward wheel (144; 244). On folding of the cycle, hinged movement of the pivot assembly (132; 232; 532) relative to the forward frame portion (130; 230; 530) moves the mounting arm (140; 240) to move the forward wheel mounting relative to the forward frame portion (130; 230; 530). The rear frame portion (120; 220; 520) and pivot assembly (132; 232; 532) are coupled such that folding of the frame portions towards each other results in the distance between the forward frame portion (130:230; 530) and forward wheel mounting (142) extending relative to each other. The cycle is provided with a lock to reversibly lock the rear and forward frame portions (120, 130; 220,230; 520,530), said lock including a locking arm (561) in an adjustable pivot mounting (565, 571).

Description

Folding cycle

The present invention relates to a folding cycle which is readily and reversibly foldable from an 'in use' configuration to a locked 'folded' configuration.

Whilst folding cycles are well known in the art, there exist a number of design challenges that are the continuing interest of designers in this field. In particular, it is desirable that the 'folded' configuration of the cycle is of minimal size and of a configuration that accommodates its carrying and/or storage. That configuration desirably also minimises the number of sharp or irregularly-shaped components protruding therefrom, which might otherwise snag on the user causing annoyance and/or minor injury.

It is desirable from a space-saving standpoint, that when in the 'folded' configuration, the wheels of the cycle are in close relationship, preferably in registration, with each other. It is particularly desirable, that when so registered the wheels are freely rotatable to enable the 'folded' cycle to be wheeled about by the user thereby avoiding any carrying thereof. Once such wheelable folded cycle is described in UK Patent Application No. 2,171 , 656 A1 , although this design necessitates the use of small cycle wheels that are less preferred from a user standpoint. For example, smaller wheels can give poorer performance over rough surfaces (e.g. potholes and off-road use). Some users also find small- wheeled cycles more difficult to handle.

The present invention provides a frame for a folding cycle accommodating 'normal' sized wheels that is readily and conveniently foldable from an 'in use' configuration to a 'folded' configuration in which the wheels are in close relationship. In a preferred aspect, the wheels are brought into registration as a result of folding the frame thereby enabling the folded cycle to be wheeled about by the user, and avoiding the user having to carry the folded cycle. The invention derives from the Applicant's appreciation that to achieve an optimal relationship between the (normal-sized) wheels in the 'folded' configuration it is necessary, on moving from the 'in use' configuration, to introduce a spacing step which increases the distance between the front wheel and forward foldable frame portion such that on folding an optimal (e.g. registration) relationship between the front and rear wheels is achievable.

The present invention also provides coupling between the 'spacing' and 'frame folding' actions such that both may be conducted in tandem, thereby reducing the number of user steps required to fold the cycle from the 'in use' to the compact and optimally, wheelable 'folded' configuration.

According to one aspect of the present invention there is provided a frame assembly for a foldable cycle comprising

a rear frame portion including a mounting for a rear wheel;

a forward frame portion, hingedly connecting to said rear frame portion such that the two are foldable towards each other; and

hingedly connecting to said forward frame portion, a pivot assembly for a mounting arm, said mounting arm including a mounting for a forward wheel,

wherein the rear frame portion and pivot assembly are coupled such that on folding of the frame portions towards each other hinged movement of said pivot assembly relative to the forward frame portion moves said mounting arm to increase the spacing between the forward frame portion and the forward wheel mounting, and wherein there is provided a lock to reversibly lock the rear and forward frame portions in the 'in use' (i.e. hinge closed) position, said lock including a locking arm in an adjustable pivot mounting.

Suitably, the locking arm (e.g. lever form) mounts in an eccentric mounting.

Suitably, the locking mechanism is arranged such that when released it can function as an extendible (i.e. variable length) link between the rear and forward frame portions. That is to say, it has a locking arm of variable length. Suitably, the variable length arm co-operates with the main coupling during the action of folding of the rear and forward frame portions towards each other (e.g. acting as a guide mechanism).

On folding of the frame portions towards each other, hinged movement of the pivot assembly relative to the forward frame portion moves the mounting arm to move the forward wheel mounting relative to the forward frame portion. The rear frame portion and pivot assembly are coupled such that said folding results in the spacing (i.e. distance) between the forward frame portion and forward wheel mounting increasing (i.e. extending) relative to each other.

The present invention provides a foldable cycle and a frame assembly therefor.

The cycle may take any form including town bike, mountain bike, leisure bike, children's bike and racing cycle.

It will be appreciated that in fully assembled form the cycle will include wheels, a seat, pedals, a drive mechanism (e.g. crank-drive) and handlebars mounted to the frame. It will also however, be appreciated that it is common to supply cycles in part-assembled form including, at the simplest level, just the frame to which various sub-components are later mounted. The cycle herein is foldable. That is to say, it has generally two configurations comprising an 'in use' configuration in which it may be put to its cycling function by a user and a 'folded configuration' in which it is folded away ready for carrying, wheeling and/or storage by the user. As will become apparent from the later description, the term 'folded configuration' includes both a fully folded configuration, in which all relevant parts are fully folded away (e.g. for storage) and a mainly folded configuration, in which the mounting arm and/or handlebars protrude to assist in wheeling thereof.

The term 'frame assembly' herein is used to mean the basic frame for the foldable cycle absent the mounting arm (e.g. dual fork or mono-fork shaped) for the forward wheel. The term 'frame and forward wheel mounting assembly' is used to denote the combination of the 'frame assembly' and forward wheel 'mounting arm'. Wheels, pedals, seat, handlebars and other sub-components are securable to these assemblies by generally known methods.

The rear frame portion includes a mounting for a rear wheel. Suitably, it also defines a mounting for pedals, a crank drive and a seat. In spatial terms, the rear frame portion generally defines a principal plane. Suitably, in use, the rear wheel rotates within that principal plane or within a plane that is coplanar therewith.

The forward frame portion hingedly connects to said rear frame portion such that the two are foldable towards each other. Suitably, the forward and rear frame portions folded close up against each other to minimise the space requirements of the 'folded' configuration. In aspects, abutting and mating engagements relationships are envisaged. In the 'in use' configuration, it will be appreciated that the forward frame portion generally lies within the principal plane defined by the rear wheel frame. A pivot assembly hingedly connects (e.g. via a hinge) to the forward frame portion. The pivot assembly is arranged for pivotable (e.g. rotatable) mounting of a mounting arm that includes a mounting for a forward wheel.

The above-described hinge connection of the forward and rear frame portions to each other and of the pivot assembly to the forward frame portion are generally achieved with structurally stiff (e.g. in torsion and bending) hinges. In aspects, this is achievable by the use of wide-spaced hinge bearings and interlocking features that engage at defined hinge positions (e.g. 'in use' position).

In one aspect, a first hinge part of the hinge defining the hinged connection is provided with a protrusion (i.e. 'male' part) and a second hinge part is provided with a cavity (i.e. 'female' part) for receipt of the protrusion on closing the hinge. Suitably, the protrusion of the first part takes the form of a wedge and the cavity of the second part is shaped accordingly. Suitably, the surface of the protrusion and/or cavity is provided with a coating of a damping material (e.g. nylon) such as to damp any movement (e.g. vibration) at the closed hinge.

In one aspect, the hinged connection between the forward frame portion and said pivot assembly hinges in the plane defined by the forward frame portion.

In another aspect however, the hinged connection between the forward frame portion and said pivot assembly hinges in a plane offset from the plane of the forward frame portion. Generally, the angle of offset is from 0.1° to 25° (e.g. 22°), and hence the plane of the hinge motion is offset from the plane defined by the forward frame portion by from 0.1° to 25° (e.g. 22°). Such offset arrangement has been found to assist in ensuring that the wheels are brought into better parallel registration in the 'folded' configuration of the cycle.

The mounting arm includes a mounting for a forward wheel. Suitably, the mounting arm also includes a mounting for handlebars, which may have any suitable configuration. It will be appreciated that in the 'in use' configuration, the pivot axis defined by the pivot assembly lies within the principal plane defined by the rear frame portion.

On folding of the cycle, hinged movement of the pivot assembly relative to the forward frame portion moves it (e.g. forwards or outwards in a relative sense) preferably such that when a mounting arm is pivotally mounted thereto the distance (i.e. spacing) between the forward frame portion and the forward wheel mounting is increased. This is an important aspect of the invention herein because without this movement and spacing action the front wheel mounting is not sufficiently spaced to allow for optimal positioning thereof in the 'folded' configuration.

Preferably, the (e.g. forwards or outwards) movement places sufficient distance (i.e. spacing) between the forward wheel mounting and forward frame portion such that the act of folding the frame portions towards each other will result in the forward and rear wheel mountings being brought generally into registration with each other. This represents an optimal 'folded' configuration since the wheel mountings (and hence wheels mounted thereto) lie side-by-side. An advantage of this optimal configuration is that the folded cycle may be readily wheeled about both wheels, each of which rotates about the same rotational axis (i.e. wheel axles aligned). In essence, the two wheels side-by-side function as a 'single wheel'. An advantage of this functional aspect is that unlike many other full-sized wheel folding cycles the front wheel does not have to be removed to achieve neat folding.

The rear frame portion and pivot assembly are coupled such that folding of the forward and rear frame portions towards each other results in the position of the forward frame portion and forward wheel mounting moving, and preferably extending (i.e. increasing spacing) relative to each other. The coupling may be achieved by any suitable coupling means including one or more coupling arms having either a simple or more tailored form.

The above described coupling enables the 'frame folding' and 'spacing' actions to be conducted in tandem, thereby reducing the complexity and number of steps required to move the cycle from the 'in use' to 'folded' configuration and vice-versa. In one aspect, as the folding motion is conducted the coupling acts to push the forward wheel mounting out and around the frame portions thereby avoiding undesirable interaction with any sub-components of the frame, particularly the pedals and/or crank drive.

Most preferably, the extension (spacing) will be to the optimal position described above in which the complete folding action results in the forward and rear wheel mountings being brought into registration with each other.

The coupling may be provided by any suitable means such as one or more suitably co-mounted coupling elements of preferably rigid form such as a single or multi-bar coupling rod.

In one aspect, the coupling is arranged to have adjustable length. For example, threaded screw adjusters may be provided to enable fine adjustment of the length of the coupling for maximum effectiveness and/or steering axis angle adjustment and/or alignment of the front and rear axles.

In another aspect, the coupling is provided with a tensioner arranged such that tension is provided to the hinge connecting the forward and rear frame portions when in the 'in use' configuration. In part, the tensioner functions to counter the 'normal riding forces' experienced by the coupling 'in use'. The tensioned coupling thereby acts to provide force to hold the hinge fast and tightly closed. The tensioned coupling thereby acts to provide force to hold the hinge fast and in place. This force must be overcome before the hinge can be opened thereby provides for enhanced strength of the hinged connection when 'in use' by a rider.

The tensioner for the coupling may in aspects be provided by a suitable spring or other resilient element(s), anywhere in the system or at the endstops to movement. In one embodiment the spring is mounted within the coupling (e.g. within a sleeve of a coupling rod). In one particular aspect, a coupling rod is provided with a hard sprung piston mechanism comprising an outer sleeve shaped respectively to receive an inner bayonet sleeve and a central piston together with internal spring. In use, the sprung piston mechanism enables travel of the inner bayonet sleeve relative to the outer sleeve wherein this travel is constrained by the action of the spring.

In alternatives, the tensionser for the coupling is supplemented with or replaced by a spring or other resilient element located at another part of the folding mechanism. Or the mechanism itself is made springy or resilient. In particular, resilience or springiness could be incorporated at coupling mountings, hinge mountings, the front and rear frame portions, pivot assembly and any stops provided to travel. The overall functional objective would be to provide an 'over centre' action, as described in more detail below.

Suitably, the frame assembly is arranged such that the pivot assembly enables the mounting arm to rotate therein such as to accommodate folding of the frame portions. Suitably, the mounting arm is moved to an optimal position to enable the accommodation of the mounting arm in the 'folded' configuration.

In one aspect herein, on folding, hinged movement of the pivot assembly relative to the forward frame portion moves said mounting arm such that the distance between the forward and rear wheel mountings extends. That is to say, the wheelbase is lengthened as a consequence of the folding action. In another preferred aspect herein, the wheelbase is not lengthened as a consequence of the folding action because as the forward wheel mounting moves away from the forward frame portion, both of these are simultaneously guided rearward under the action of the main hinge (between forward and rear frame portions).

The mounting arm is generally provided with handlebars (e.g. on a stem mounting). Suitably, on folding, the pivot assembly acts such as to enable the mounting arm with handlebars to rotate therein such as to readily accommodate the arm and handlebars on folding of the frame portions. Suitably, the handlebars or stem mounting therefor are moved to a position that enables their optimal location in the 'folded' configuration.

In one aspect, in the 'folded' configuration, the handlebars or stem mounting therefor are located such as to function as a handle for wheeling about the folded cycle by way of the wheels (in a side-by-side configuration). In other aspects, other parts of the frame assembly or one or more further additional features provide this handle function.

In aspects, any handle is foldable, retractable, rotatable, or otherwise movable to an optimum position (e.g. ergonomic) for ease of wheeling of the folded cycle by a user. Suitably, this movement of the handle to an optimum position may be coupled to the overall folding action.

One or more of the hinges or of the coupling or locking elements described above may use an 'over-centre' action such that there is a spring bias which arises either from the hinge/coupling geometry or by the use of spring elements. The spring bias may be to either or both ends of the folding action. Such spring bias may in aspects, be employed to assist the folding or unfolding action. In other aspects, it may be employed to bias the frame to the 'folded' or "unfolded' configurations. Suitably, the forward and rear wheel mountings herein take the form of single- sided 'mono-fork' mountings, although more traditional dual-fork mountings may also be employed. The advantage of using 'mono-fork' mountings is that the wheels are enabled to locate nearer to each other in the 'folded' configuration, thereby further saving space. It will be appreciated that where 'mono-forks' mountings are employed the forward and rear wheel mountings will be arranged as a mating pair to enable close wheel location on folding. Where traditional 'dual fork' mountings are used the front wheel may remain in parallel with the forward frame portion and not rotate 180° about the steering axis.

Suspension systems may be provided to any wheel mountings.

Suitably, the hubs of the wheels may lock lightly or more engagedly together in the 'folded' configuration. One or more latches may be provided thereto or elsewhere on the frame of any suitable form including magnetic latches, mechanical latches, sprung latches, interference fit latches, retracting ball latches, press-stud latches and Velcro (trade name) type latches.

The wheels of the cycle may be arranged to be removable on folding, thereby further reducing the size of the 'folded' configuration.

The wheels may have any suitable size. It is an advantage of the present invention that 'normal-sized' wheels (e.g. 60 to 75cm) are readily accommodated as well as the 'mini-sized' wheels (e.g. < 45cm) of many fold up bikes.

The rear wheel frame portion is generally provided with a mounting for a seat stem upon which a seat is accommodated. The seat stem is suitably adjustable in both up/down and back forward senses and may be provided with various locking mechanisms. In aspects, the seat stem retraction or removal may be independent or it may be coupled in some way to the main folding action. In one aspect, the frame assembly is provided with an energy storage device capable of releasing power to assist the folding or unfolding action. Examples of such devices include compressed air devices, electrical devices, stored spring energy devices, batteries and servomotors.

In aspects, the handlebars and/or stem mounting therefore may retract or be removable. The retraction or removal thereof may be independent or it may be linked or coupled in some way to the cycle folding action.

The frame assembly and any additional components of the foldable cycle may be made from any suitable material including metals, woods, composites, plastic polymeric materials and any combinations thereof. Suitably, materials are selected for their low-weight, stiffness and robustness properties.

The frame assembly may additionally be provided with other features such as stands, luggage carriers, combined luggage carriers / stands, enclosures and motor powering (e.g. electric motor).

According to another aspect of the present invention, there is provided a frame and forward wheel mounting assembly for a foldable cycle comprising

a rear frame portion including a mounting for a rear wheel;

a forward frame portion, hingedly connecting to said rear frame portion such that the two are foldable towards each other;

hingedly connecting to said forward frame portion, a pivot assembly for a mounting arm; and

pivotally connecting to said pivot assembly, a mounting arm including a mounting for a forward wheel wherein the rear frame portion and pivot assembly are coupled such that on folding of the frame portions towards each other hinged movement of said pivot assembly relative to the forward frame portion moves said mounting arm to increase the spacing between the forward frame portion and the forward wheel mounting, and

wherein there is provided a lock to reversibly lock the rear and forward frame portions in the 'in use' (i.e. hinge closed) position, said lock including a locking arm in an adjustable pivot mounting.

Suitably, the locking arm mounts in an eccentric mounting.

On folding, hinged movement of said pivot assembly relative to the forward frame portion moves said mounting arm to move the forward wheel mounting relative to the forward frame portion. The rear frame portion and pivot assembly are coupled such that folding of the frame portions towards each other results in the spacing (i.e. distance) between the forward frame portion and forward wheel mounting extending relative to each other.

In essence, the frame and forward wheel mounting assembly comprises the frame assembly described hereinbefore in combination with the mounting arm for the forward wheel.

According to a further aspect of the present invention there is provided a frame assembly for a foldable cycle comprising a rear frame portion including a mounting for a rear wheel; a forward frame portion, hingedly connecting to said rear frame portion such that the two are foldable towards each other; and a lock for reversibly locking the rear and forward frame portions together in a hinge closed position, wherein said lock includes a locking arm in an adjustable pivot mounting. The locking system using the adjustable pivotal mounting for the locking arm is easy to operate, uses few components and is structurally strong and light. The adjustable pivotally mounted locking arm is typically located in embodiments herein, between the coupling rod and the rear frame portion. The adjustable pivot is suitably provided by mounting the locking arm in an eccentric mounting that can alter the tension in the coupling rod. Use of an eccentric mounting with a locking arm provides the adjustable pivot with a high mechanical advantage. In variations, other adjustable mountings with high mechanical advantage may also be used (e.g. levers, gears, hydraulics).

The eccentric mounting with a locking arm provides a high mechanical advantage which can be used to tension the coupling rod and so lock both hinges tightly closed. The eccentric mounting, when turned in the opposite direction also reduces tension to ease unlocking the hinges when folding the bike up. This reduces the need for the spring loaded or adjustable length coupling rod as previously described, which was needed to extend to go 'over- centre' past the hinge when the joint is being fully extended.

The locking arm attached to the eccentric mounting can also be arranged to connect to the pivot assembly when the bicycle is in riding mode, preferably when the coupling rod is in tension. The connection between the locking arm and the pivot assembly will ideally put the locking arm into tension as well as lock it to the pivot assembly. This may be achieved by the use of a standard 'quick- release' lever as normally used to connect and tension bicycle wheel axles or by the use of any other suitable mechanical, connection device (e.g. threaded device, locking device). The overall lengths of the coupling rod and the locking arm may be adjustable (e.g. by having the ends thereof provided with screw threads), and the hinged joints may be provided with adjustable or replaceable resilient stops so that any wear in the system can be taken out. By having both the coupling rod and the locking arm in tension when the bicycle is in riding mode the frame is kept rigid and strong in bending and in torsion. This gives the advantage of a very efficient structure as is essential for a bicycle.

Preferably, the locking arm is positioned to be at a maximum distance from the hinge axes (for example on the other side of the frame tubes to the coupling rod) so once attached to the pivot assembly and tensioned, there is maximum moment holding the hinges closed and the bike frame rigid. The principal (e.g. generally vertical) hinge between the rear and front frame portions may be angled away from the frame at its lower end to be outside both the coupling rod and locking arm. When the cycle is in the folded mode this maximises the closing force due to tension in these links ansd also keeps the hinge as compact as possible at the top of the frame, nearer to the rider.

When the cycle is in the folded mode, the small adjustments to the coupling rod mounting position made by rotating the locking arm and the eccentric mounting can be used to adjust the front and rear wheel registration and axle alignments. This action can also form the basis of a locking system between the wheels, whereby front and rear hubs are hooked or similarly joined together as they are moved radially past each other by this action. This is to replace or in addition to wheel locking mechanisms previously described.

This locking system can be arranged with the principal, generally vertical hinge on the right (or left) of the frame, and the locking arm and coupling rod on the left and right (or vice versa) respectively. When this hinge is on the right the transmission (which is normally also on the right), will be sandwiched in to the middle of the folded frame, and between the wheels. This has the advantage of protecting the transmission and also protecting the user from the oil and dirt of the transmission. If the vertical hinge is on the left of the frame as described earlier, but now with the coupling rod on the left and the locking arm on the right, then when the bike is folded, the wheels may come into closer registration with each other, especially if they are mounted on single sided 'mono-forks' (arranged to be on the outside when folded).

Considering the folded form of the bicycle, a handle element may be built into or placed near to the area near the main hinge (e.g. between the rear and front frame portions). This position is the maximum distance away from the wheels and allows the folded bike to be gripped in position that makes wheeling it very easy.

According to a further aspect of the present invention there is provided a foldable cycle comprising the frame and forward wheel mounting and additionally forward and rear wheels; handlebars; a drive mechanism; and a seat. Optionally, gearing may be provided to the drive mechanism.

According to other aspects of the present invention there are provided methods for folding and unfolding the frame assembly and frame and forward wheel mounting assembly described herein from an 'in use' to 'folded' configuration.

Embodiments of the present invention will now be described with reference to the accompanying drawings in which:

Figures 1a to 1f show perspective views of a first folding cycle herein in various stages as the cycle is folded up from the 'in use' configuration (Figure 1a) to the 'folded' configuration (Figure 1f);

Figure 2 shows a perspective view of a detail of a coupled folding mechanism herein; Figure 3a shows a perspective view of a third folding cycle herein in riding mode viewed from the left side and below;

Figure 3b shows a close up view of the front frame portion of the cycle of Figure 3a in the frame locked position;

Figure 3c shows a close up view of the front frame portion of the cycle of Figure 3a in the frame unlocked position;

Figure 4a shows a perspective view of the third folding cycle herein in riding mode viewed from the right side and above;

Figure 4b shows a close up view of the principal, generally vertical hinge and the coupling rod and locking arm mountings of the cycle of Figure 4a;

Figure 4c shows an exploded view of the coupling rod and locking arm mountings of Figure 4b;

Figures 5a to 5e show perspective views of the third folding cycle herein in various stages as the cycle is folded up from the 'in use' configuration;

Figures 6a shows a perspective view of the third folded cycle herein from a typical users point of view;

Figure 6b shows a close up of the hinge and handle area of the folded cycle of Figure 6a;

Figure 6c shows the folded cycle of Figure 6a as wheeled by a user to illustrate how handle positioning aids the user; Figure 7 shows a perspective view of the hinged connection between the forward frame portion and pivot assembly of a folding cycle herein;

Figures 8a and 8b respectively show side-perspective and top views of a fourth folding cycle herein in the folded configuration; and

Figure 8c shows a detail of the hinge assembly and forward frame portion of the folding cycle of Figure 8a.

Referring now to the drawings, in Figures 1a to 1f there is shown a folding cycle 110 herein in which a coupling is provided to guide the folding action. Various stages are shown as the cycle is folded up from the 'in use' configuration (Figure 1a) to the fully 'folded' configuration (Figure 1f). For ease of reference and understanding, not all parts are labelled in every drawing, but only the most important parts in relation to the action at that stage of the folding up process.

As may be seen in Figure 1a, the folding cycle 110 comprises a rear frame portion 120 and a front frame portion 130 that are hingedly joined by stiff folding hinge 135 in order that the two frame portions 120, 130 may be folded towards each other. The rear frame portion 120 is also provided with rear wheel mounting 122 in 'mono fork' form to which rear wheel 123 is fixed at hub 124. Also provided to the rear frame portion is seat stem mounting 126 which receives adjustable seat stem 127 and seat 128. Further provided to the rear frame portion are pedals 129a (one only visible) which drive crank which in turn is provided with a chain, belt, shaft (not visible) or other means for driving rear wheel 123. The front frame portion 130 is provided with pivot assembly 132 to which it hingedly connects via hinge 133 which allows for hinged motion thereof about a horizontal axis. Coupling rod 150 is fixed to both rear frame portion 120 and pivot assembly 132 to provide a coupling therebetween. Mounting arm 140 pivotally connects to pivot assembly 132. The mounting arm is provided with handlebars 146 on stem mounting 147 and 'mono-fork' form wheel mounting 142 for front wheel 144 that connects thereto at a hub (not visible). The pivot assembly 132 enables rotational movement of the mounting arm 140 and front wheel 144, stem mounting 147 and handlebars 146 that are associated therewith.

Figure 1b shows a first stage of the folding action. At folding hinge 135, the rear frame portion 120 and front frame portion 130 hingedly move towards each other (motion A). At pivot assembly 132, the mounting arm 140 is rotated clockwise (motion B) such that the wheels 123, 144 remain approximately parallel and the handlebars 146 are moved out and away from the folding parts. At hinge 133, the mounting arm 140 hingedly rotates upwards (motion C) in response to the action of coupling rod 150 acting on the pivot assembly 132 such that the front wheel 144 is initially pushed generally forwards and the handlebars 146 initially move backwards. It will thus, be appreciated that three separate coupled motions are occurring as the frame portions 120, 130 fold together, the net effect of which is to increase the distance (spacing) between the front wheel 144 and forward frame portion 130 and push the front wheel 144 and mounting arm 140 out of the way of the folding action, and in particular away from the pedals 129a. In this example, the distance between the rear and front wheels 123, 144 does not increase because although the mounting arm 140 rotates upwards about hinge 133 (motion C) it is also rotating clockwise (motion B) and backwards

(motion A) and the net effect of these combined actions is that the wheelbase is marginally reduced during the initial part of the folding action. Coupling rod 150 is fixed to both rear frame portion 120 at a first attachment point and pivot assembly 132 at a second attachment point to provide a coupling there between.

In subsequent stage, Figure 1c the three coupled aspects of the folding action are continued further. The rear frame portion 120 and front frame portion 130 hingedly are moved further towards each other. The mounting arm 140 is further rotated clockwise such that the handlebars146 are moved further out and away from the folding parts. The mounting arm 140 is also further rotated upwards in response to the action of coupling rod 150 acting on the hinged pivot assembly 132 such that the front wheel 144 is pushed out and around.

In Figure 1d, both the rear frame portion 120 and front frame portion 130 and the rear and front wheels 123, 144 are respectively brought into mating relationships with each other. The handlebars 146 remain positioned well away from the folding path.

In Figure 1e, the front 144 and rear 123 wheels are in registration with each other. The respective 'mono fork' mountings 122, 142 are located exterior to the wheels 123, 144 and can then act as a barrier (or part-barrier) to user contact with the wheel hubs and transmission (not visible).

In Figure 1f, the fully 'folded' configuration, the seat 128 is retracted (e.g. manually or automatically) and the stem mounting 147 to the handlebars 146 may be seen to protrude thereby providing an effective handle 147 for wheeling the folded form about the wheels 123, 144.

It will be appreciated that in the first (Figs. 1a to 1f) folding cycle described above, the 'spacing' and 'folding' actions are combined whereby the front wheel 144 when being brought into the folded position is generally parallel to the rear wheel 123, and is pushed out side ways to clear pedal 129a and crank and then automatically guided to lie alongside the rear wheel 123.

In essence, in the context of the first folding cycle (Figs. 1a to 1f), the coupling rod 150 links the 'spacing' and 'folding' actions such that the initial spacing of the front wheel mounting arm 140 and forward frame portion 130 is 'absorbed' into the rest of the actions. In aspects, axis of motion B (which can also be the steering axis) allows the front wheel 144 to remain parallel to the rear wheel 123, and during the folding action allows approx 180 degrees of rotation (of pivot assembly 132). The handlebars 146 clear the frame during the folding action and importantly the front wheel 144 is guided to move alongside the rear wheel 123 thereby clearing the left-hand pedal 129a/crank assembly.

Figure 2 shows a detailed view of coupled folding mechanism herein, which for example, could be employed in the folding cycle of Figures 1a to 1f.

Stiff folding hinge 235 hingedly joins foldable rear 220 and front 230 frame portions. Pivot assembly 232 joins to the front frame portion by way of hinge 233, which enables the pivot assembly 232 to be hingedly moved relative to the forward frame portion 230 in a plane of movement defined by the hinge 233. This plane of movement generally corresponds to the (forward) plane defined by the forward frame portion 230. The pivot assembly 232 is also provided with a pivot mounting 231 for mounting arm 240, which enables axial rotation of the mounting arm 240 about axis AB as shown. The mounting arm 240 has front wheel 244 and handlebars (not visible) attached, and this axial rotation thereby enables steering of the cycle.

Coupling rod 250 joins to rear frame portion 220 at first attachment point 252 and pivot assembly 232 at second attachment point 251. It may thus, be appreciated that any movement of the forward frame portion 230, rear frame portion 220 and pivot assembly 232 will be coupled.

The representation of Figure 2 shows the coupled folding mechanism in a part- folded configuration in which the forward frame portion 230 has been moved towards the rear frame portion 220. As a result of this movement, the coupling rod 250 has acted to push the pivot assembly 232 away from the forward frame portion 230, the pivot assembly 232 moving about hinge 233. The front wheel 244 on mounting arm 240 is thereby pushed out and away from the folding action. In Figure 3a a third folding cycle 510 is shown 'in use' with the rear frame portion 520 and the front frame portion 530.

Figure 3b shows the area of the front frame portion 530 in more detail locked in the 'in use' mode. In this mode the the coupling rod 550 is in tension and links the rear frame portion 520 to the pivot assembly 532. The principal, generally vertical hinge with axis 535 connects front and rear frame portions 530 and 520. The generally horizontal hinge with axis 533 connects the front frame portion 530 to the pivot assembly 532. The axis 533 of the hinge may be seen to be arranged such that the pivot assembly 532 hinges in the plane defined by the forward frame portion 530. Locking arm 561 is connected to pivot assembly 532 by 'quick-release' mechanism 563, which locks it to prevent rotation of the eccentric mounting 565 within rear frame mounting 571. The 'quick-release' mechanism 563 also adds tension to locking arm 561.

Figure 3c shows the same area as Figure 3b, with the 'quick-release' mechanism 563 released from the pivot assembly 532, and locking arm 561 rotatable about eccentric mounting 565, which releases tension in coupling rod 550. This relaxation of tension allows a small rotation of pivot assembly 532 about hinge axis 533.

Figure 4a shows a folding cycle 510 in the 'in-use' mode. This is the right side corresponding to Figure 3a. Figure 4b shows the area near the main generally vertical hinge with axis 535 and how it connects front and rear frame portions 530 and 520. In this view the coupling rod 550 and its adjustable pivot 567 is seen. This view shows how the hinge axis 535 is outside the coupling rod 550 and locking arm 561 such that tension in these links keeps the hinge firmly closed.

Figure 4c shows the eccentric mounting 565 and locking arm 561 exploded from mounting 571 in rear frame portion 520. The innepr part 569 of eccentric mounting 565 is now visible. The adjustable pivot 567 for coupling rod 550 fits into into the inner part 569 of eccentric mounting 565. In this view the locking arm 561 and eccentric mounting 565 rotate within mounting 571 in rear frame portion. Due to the offset axis of eccentric 569 the adjustable pivot is moved generally forward, relaxing tension in coupling rod 550.

In Figures 5a to 5e there is shown a folding cycle 510 herein, in which a coupling is provided to guide the folding action. This is largely the same as previously described and illustrated (except in this version the cycle folds to the right). Various stages are shown as the cycle is folded up from the 'in use' configuration (Figure 5a) to the fully 'folded' configuration (Figure 5e). Handlebar mounting stem oblique lockable hinge 548 attaches handlebar stem mounting 547 and handlebars 546 to front wheel assembly. Seat stem mounting 526 is part of the rear frame portion 520, and accepts and supports seat stem 527, on which seat 528 is mounted. Front and rear wheel assembly hubs are 543 and 524 respectively.

Figure 5b shows an early stage of folding the cycle; handlebar mounting stem oblique hinge 548 is unlocked and rotated as shown to lower handlebar stem mounting 547 and handlebars 546, to lie next to the front wheel. Seat stem 527 retracts into the seat stem mounting lowering the seat 528 to below below the height of the rear wheel. Locking arm 561 is released and rotated, which as previously described, relaxes tension forces.

Figure 5c shows how the coupling rod 550, pushes the pivot assembly 532, as the main, near vertical hinge, with axis 535 is opened. The guiding action is continued in figure 9d where the wheel hubs 543 and 524 are guided towards each other.

Figure 5e shows the folded cycle, in this case the transmission 525 is sandwiched between the frame portions and wheels protecting the transmission and also protecting the user from the oil and dirt of the transmission. The right side handle 528 is now also visible. The small adjustments to the coupling rod mounting 567 position, made by rotating the locking arm 561 and the eccentric 569 can be used to adjust the front and rear wheel registration and axle alignments. This action can also form the basis of a locking system between the wheels; whereby front and rear hubs 543 and 524 are hooked or similarly joined together as they are moved radially past each other by this action

Figure 6a shows a view onto the hinge and handle areas, which are shown in detail in Figure 6b. With the hinge axis 535 central, left handle 581 and right handle 582 shown here integrated into the joint.

Figure 6c shows how the folded cycle is held by these handles (or other handles) to make wheeling it along easy and so avoiding having to carry the cycle.

Figure 7 shows the hinged connection between the forward frame portion 530 and pivot assembly 532 of a folding cycle herein, which cycle might for example have the overall structure of any of the folding cycles of Figures 3a to 6c.

Figure 7 shows forward frame portion 530 connecting to the pivot assembly 532. Coupling arm 550 also connects to the pivot assembly 532. It may also be seen that wedge-shaped protrusion 537 protrudes from the forward frame portion such that when the hinge is closed the protrusion 537 wedges in cavity 538 provided in the hinge assembly 532. The wedge-shaped protrusion 537 is coated with a nylon coating such as to ensure snug receipt by the cavity and to damp any movement at the hinge on use of the cycle.

Figures 8a to 8c show aspects of a fourth folding cycle that may be appreciated to be a variation of any of the folding cycles previously described at Figures 3a to 6c. Figure 8c shows a detailed view of the area of the forward frame portion 530 and hinge assembly 532. The axis 533 of the hinge may be seen to be arranged such that the pivot assembly 532 hinges in a plane slightly offset from the plane defined by the forward frame portion 530. It has been found that use of such an offset hinge arrangement assists in bringing the wheels 523, 544 of the cycle into better parallel registration when the cycle is folded up as shown in Figures 8a and 8b.

Claims

CLAIMS:

1. A frame assembly for a foldable cycle comprising a rear frame portion including a mounting for a rear wheel; a forward frame portion, hingedly connecting to said rear frame portion such that the two are foldable towards each other; and hingedly connecting to said forward frame portion, a pivot assembly for a mounting arm, said mounting arm including a mounting for a forward wheel, wherein the rear frame portion and pivot assembly are coupled such that on folding of the frame portions towards each other hinged movement of said pivot assembly relative to the forward frame portion moves said mounting arm to increase the spacing between the forward frame portion and the forward wheel mounting, and wherein there is provided a lock to reversibly lock the rear and forward frame portions, said lock including a locking arm in an adjustable pivot mounting.

2. A frame assembly according to claim 1 , wherein on folding of the frame portions towards each other said spacing between the forward frame portion and forward wheel mounting increases such that the forward and rear wheel mountings may be brought into registration with each other.

3. A frame assembly according to either of claims 1 to 2, wherein the rear frame portion and pivot assembly are coupled by a coupling comprising one or more rigid coupling elements.

4. A frame assembly according to claim 3, wherein the coupling is of adjustable length.

5. A frame assembly according to claim 4, wherein the coupling is provided with one or more threaded screw adjusters to enable fine adjustment of the length thereof.

6. A frame assembly according to any of claims 3 to 5, the coupling is provided with a tensioner for providing tension to said hinged connection between the forward and rear frame portions.

7. A frame assembly according to claim 6, wherein said tensioner comprises a resilient element.

8. A frame assembly according to claim 7, wherein said resilient element comprises a spring.

9. A frame assembly according to either of claims 7 or 8, wherein said resilient element acts to provide an over centre action.

10. A frame assembly according to any of claims 7 to 9, wherein said resilient element locates within a cavity defined by the coupling.

11. A frame assembly according to claim 10, wherein the coupling is provided with a hard sprung piston mechanism comprising an outer sleeve shaped respectively to receive an inner bayonet sleeve and a central piston together with internal spring, wherein the sprung piston mechanism enables travel of the inner bayonet sleeve relative to the outer sleeve which travel is constrained by the action of the spring.

12. A frame assembly according to any of claims 1 to 11 , wherein said locking arm mounts in an eccentric mounting.

13. A frame assembly according to any of claims 1 to 12, wherein the locking arm is of variable length.

14. A frame assembly according to claim 13, wherein the locking arm cooperates with the coupling on folding of the rear and forward frame portions towards each other.

15. A frame assembly according to any of claims 3 to 14, wherein on folding of the frame portions towards each other the coupling acts to push the forward wheel mounting out and around the forward and rear frame portions.

16. A frame assembly according to any of claims 1 to 14, wherein the pivot assembly enables the mounting arm to rotate therein to a position, which readily accommodates folding of the frame portions towards each other.

17. A frame assembly according to any of claims 1 to 16, wherein the rear wheel frame portion is provided with an adjustable mounting for a seat stem.

18. A frame assembly according to any of claims 1 to 17, wherein the hinged connection between said forward frame portion and said pivot assembly comprises first and second hinge parts, wherein said first hinge part is provided with a protrusion and said second hinge part is provided with a cavity for receipt of the protrusion on closing the hinge.

19. A frame assembly according to claim 18, wherein said protrusion has the form of a wedge.

20. A frame assembly according to either of claims 18 or 19, wherein at least part of the surface of the protrusion and/or cavity has a coating of a damping material for damping movement at the closed hinge.

21. A frame assembly according to any of claims 1 to 20, wherein wherein the hinged connection between said forward frame portion and said pivot assembly hinges in the plane of the forward frame portion.

22. A frame assembly according to any of claims 1 to 20, wherein wherein the hinged connection between said forward frame portion and said pivot assembly hinges in a plane offset from the plane of the forward frame portion.

23. A frame and forward wheel mounting assembly for a foldable cycle comprising

a frame assembly according to any of claims 1 to 22; and

pivotally connecting to said pivot assembly, a mounting arm including a mounting for a forward wheel.

24. A foldable cycle comprising the frame and forward wheel mounting assembly according to claim 23; and

attached respectively to said forward and rear wheel mountings, forward and rear wheels;

attached to the mounting arm, handlebars;

attached to the rear frame portion, a seat stem for receipt of a seat and a drive mechanism for said rear wheel.

25. A foldable cycle according to claim 24, wherein the forward and rear wheels are of diameter from 45 to 75cm.

26. A frame assembly for a foldable cycle comprising

a rear frame portion including a mounting for a rear wheel;

a lock for reversibly locking the rear and forward frame portions together in a hinge closed position,

wherein said lock includes a locking arm in an adjustable pivot mounting.

27. A frame assembly according to claim 26, further comprising a coupling element for coupling said forward and rear frame portions.

28. A frame assembly according to either of claims 26 or 27, wherein said locking arm mounts in an eccentric mounting.

29. A frame assembly according to any of claims 26 to 28, wherein the locking arm is of variable length.

30. A frame assembly according to any of claims 26 to 29, wherein the locking arm includes a quick release mechanism.