Patent Description:
By "scooter" we mean a stand-up scooter or 'kick' scooter, rather than a motorcycle-type scooter. Scooters according to the present invention are distinguished in having a deck, generally proximate and parallel to the floor with wheels mounted thereon. An upright or 'tiller' is provided extending vertically upward from the forward end of the deck featuring handlebars to facilitate stability and steering.

Traditionally such scooters have been human-powered, specifically by pushing the scooter along with one foot whilst the other (load-bearing) foot remains on the deck. More recently, motorised scooters have appeared on the market. Initial designs utilised internal combustion engines, but battery-powered electric scooters have grown in popularity since the early <NUM> and represent a fast, efficient, environmentally friendly and convenient way to travel.

Some kick scooters (in particular those marketed towards the junior market) typically have a single front wheel and a single rear wheel. They utilised a simple steering system in which rotation of the tiller about a vertical axis, using the handlebars, would also rotate the front wheel.

One such known scooter is the Moove (TM) range of scooters. These battery powered electric scooters are of a two wheel design (front and rear) with the front wheel pivoting about a substantially vertical axis to steer. Rotation of the handlebars about that axis rotates the front wheel. These products are based on traditional two-wheeled "trick" scooters.

The Bajaboard (TM), although not a scooter per se, is a four-wheeled electric skateboard designed for off-road use. It can be steered by rotating the board about a longitudinal or horizontal axis (i.e. "leaning" on the board).

The Cycleboard (TM) is a three-wheeled electric scooter that features a "lean to steer" steering system. Two wheels are provided at the front, and one at the rear. <CIT> relates to the Cycleboard (TM). According to that document, "A steering transmission arm transmits lateral movement via a pair of steering rods to the front wheels, so that when the scooter deck is leaned to one of the leaning configurations, the movement causes the steering transmission arm to turn the front wheels via the steering rods.

<CIT> discloses a scooter in which the two front wheels are rotatable relative to a frame about respective wheel pivots having vertical steering axes. The deck is also mounted for rotation about a "roll" or horizontal axis in the direction of travel. The upright of the disclosed scooter is foldable towards the deck, but otherwise is rigidly attached thereto such that it can be used to help "roll" or "lean" the deck about the roll axis. The upright is rotationally fixed about the vertical axis.

A mechanism is provided such that when the deck is leaned to the side about the roll axis, the wheels turn about their respective steering axes (in the same direction as the roll). The mechanism has a steering transmission arm pivoted to the frame at a first end, coupled to the deck at a mi-point and attached to two steering rods at a second end. When the deck is rotated about the horizontal axis, the steering transmission arm is driven in rotation and as such drives the steering arms to rotate the respective wheels about their respective steering axes.

Essentially, there are two types of steering provided in the prior art. One type is "vertical pivot" steering found on most two-wheeled trick scooters. This type of steering is useful for low speed movements and tricks because it is highly sensitive and can offer a high degree of maneuverability. The other type is "lean to steer" steering found on three-wheeled off-road and high-speed electric scooters. This type of steering is suitable for high-speed, stable "carving" turns, but lacks manoeuvrability at low speeds. Indeed, performing tight turns at low speed would require the rider to roll the deck to a significant degree which would be difficult.

It is an aim of the present invention to overcome, or at least mitigate the aforementioned problems with the prior art.

According to a first aspect of the invention there is provided a scooter according to claim <NUM>.

Advantageously, this dual mode steering provides both the ability to provide a high degree of manoeuvrability in the first mode for low speeds, and a 'carving' high speed mode of steering using deck roll. Both modes can be used together, without having to switch any controls on the scooter.

By "first mode of steering" and "second mode of steering" we do not mean that a positive control is required to switch between two modes- rather that the steering can be operated using the first mode and / or the second mode. In other words, the modes can be utilised independently or simultaneously at any point during use of the scooter at the rider's preference.

Preferably a central boss is provided, wherein;.

Preferably the steering system comprises a pair or steering arms connected to respective front wheels, the steering arms being connected to a steering hub, wherein the steering hub is configured to move with rotation of the tiller in the first steering mode, and with rotation of the deck in the second steering mode.

Preferably the steering hub is mounted for rotation with the tiller, the tiller is mounted for rotation in a tiller pivot member about the vertical axis, and the tiller pivot member is mounted for rotation in the central boss about the horizontal axis.

Preferably a resilient centring mechanism is provided for resiling the tiller to a predetermined neutral rotational position relative to the central boss.

Preferably an anti-camber mechanism is provided for resiling the deck to a predetermined neutral rotational position relative to the central boss.

Preferably the two front wheels are mounted to the central boss via a suspension system.

Preferably the suspension system is a double-wishbone suspension system.

Preferably the rear wheel is mounted for rotation in a rear wheel mount, and in which the deck is rotatable about the horizontal axis about the rear wheel mount.

There is also an embodiment having four wheels, in which a pair of rear wheels and a rear steering mechanism is provided configured to steer the two rear wheels about respective steering axes.

Preferably rotation of the deck about the horizontal axis steers the wheels.

Preferably rotation of the deck about the horizontal axis causes the front wheels to steer in a first direction about their respective steering axes, and causes the rear wheels to steer a second, opposite, direction about their respective steering axes.

Preferably the rear steering system is configured to steer the rear wheels in the second mode of steering but not in the first mode of steering.

Preferably the rear steering mechanism is adjustable to provide at least two steering settings, in which each steering steers the wheels by a different angle in response to a predetermined degree of deck roll.

Preferably the rear steering mechanism is configured for Ackermann steering.

Preferably the front steering mechanism is configured for Ackermann steering.

Example scooters in accordance with the present invention will now be described with reference to the accompanying drawings in which:.

<FIG> and 2b are various views of an entire electric scooter <NUM> according to a first aspect of the present invention. For the purposes of the present disclosure it is useful to define global directions and axes as follows:.

The scooter <NUM> comprises a deck assembly <NUM>, a tiller assembly <NUM>, a front wheel suspension and steering assembly <NUM> and a rear wheel assembly <NUM>. Comparing <FIG> and <FIG> and <FIG>, the scooter <NUM> can be moved from an unfolded condition where the deck <NUM> is on the ground with the tiller <NUM> normal thereto (upright) to a folded condition where the deck and tiller are parallel.

Referring to <FIG>, the deck assembly <NUM> is shown.

The deck assembly <NUM> comprises a deck panel <NUM> having a front portion <NUM>, rear portion <NUM> and a central portion <NUM>. The front and rear portions <NUM>, <NUM> are defined by upturned, curved regions <NUM>, <NUM> respectively, extending at <NUM> degrees to the flat, planar central portion <NUM>. Each of the front and rear portions <NUM>, <NUM> are also narrower in the lateral direction than the central portion <NUM>, being tapered at the curved regions <NUM>, <NUM>. The deck panel <NUM> is constructed from a composite material to be lightweight and stiff (e.g. carbon fibre reinforced polymer).

The deck assembly <NUM> comprises a front deck insert <NUM> and a rear deck insert <NUM>. The deck inserts <NUM>, <NUM> are constructed from a metal material (so they are able to hold a thread) and embedded in the panel <NUM> with fixing holes <NUM>, <NUM> respectively being open to the surface of the deck assembly <NUM>. Each deck insert <NUM>, <NUM> extends through the respective curved region <NUM>, <NUM>.

The rear deck insert <NUM> comprises a locking plate <NUM> constructed from a ferromagnetic material.

<FIG> show the tiller <NUM>. The tiller <NUM> comprises:.

The tiller pivot and folding subassembly <NUM> is shown in <FIG>. The assembly comprises a tiller pivot shaft <NUM>, a tiller mount <NUM> and a catch <NUM>.

The tiller pivot shaft comprises a main shaft portion <NUM> and a head <NUM> defining a tilt pivot shaft bore <NUM> (<FIG> and <FIG>).

The tiller mount <NUM> is attached to the main part of the tiller, and moveable therewith. The tiller mount <NUM> is pivotably mounted to the tiller pivot shaft <NUM> via a tilt pivot shaft <NUM> which is engaged with the tilt pivot shaft bore <NUM>. This enables the tiller mount <NUM> (and tiller) to rotate about a folding axis FA.

The catch <NUM> comprises two spaced-apart plates either side of the tiller mount <NUM>. The catch <NUM> comprises a pedal <NUM> rotatable between a stowed position where is sits flush with the tiller mount <NUM> (<FIG>) and a deployed position rotated <NUM> degrees to project approximately parallel with the deck. This enables a user's foot to actuate the pedal <NUM>. The catch <NUM> has a pivot pin <NUM> to enable rotation relative to the tiller mount <NUM>. The catch <NUM> further comprises an abutment shaft <NUM> (<FIG>).

The battery assembly <NUM> is shown in <FIG>. The battery assembly <NUM> comprises a tiller subassembly <NUM> and a battery module <NUM>. The tiller subassembly comprises electrical power connectors for the transfer of electrical energy from the battery module (e.g. when powering the wheel motors, lights, sounds) and to the battery module when recovering energy from e.g. braking (reverse driving the wheel motors).

The battery module <NUM> is configured to be easily installed and removed in the base of the tiller. The module <NUM> comprises a lever <NUM> which can be lifted in direction L to release a mechanical locking mechanism to allow removal of the module <NUM> in direction BR. Replacement of the module <NUM> reconnects the electrical contact between the tiller subassembly <NUM> and the battery module <NUM>.

There are three types of battery module <NUM> with this particular embodiment:.

The standard and high capacity packs are unitary modules that provide predetermined amounts of energy (the high capacity pack simply containing more cells).

The travel pack, embodiment in module <NUM>, has a 320Whr (Watt-hours) energy storage capacity. The pack <NUM> comprises a module carrier <NUM>, a first battery sub-module <NUM> and a second battery sub-module <NUM>. Each sub-module <NUM>, <NUM> has a capacity of 160Whr. This means that the battery sub-modules <NUM>, <NUM> may be separate (e.g. by removing both from the carrier <NUM>) and stored in passenger carry-on baggage under CAA (Civil Aviation Authority) rules. This allows the authorised transport of the scooter and associated batteries on aircraft.

The control assembly <NUM> is located at the uppermost part of the tiller (furthest from the deck in the unfolded condition) and is shown in <FIG> and <FIG>. The control assembly comprises a base region <NUM> from which first and second arms <NUM>, <NUM> project vertically upwardly and outwardly at a first portion <NUM>, <NUM> respectively, upwardly and inwardly at a second portion <NUM>, <NUM> respectively and meeting a crossbar portion <NUM> joining the respective free ends. The control assembly therefore forms a hexagon shape.

A user interface <NUM> is provided mounted to the base region <NUM> and comprises an information screen which can be used to inform the rider of information such as speed, range remaining etc. The screen can also function as an input device to control e.g. sounds, cruise control etc..

The crossbar <NUM> comprises the primary driving controls. An accelerator / brake control <NUM> is provided comprising a single rotatable control member <NUM> rotatable about a horizontal control axis CA (parallel to the crossbar <NUM>). The member <NUM> comprises two spaced-apart control surfaces <NUM>, <NUM>. One control surface <NUM> is proximate the left hand arm <NUM>, and another surface <NUM> proximate the right hand arm <NUM>. The surfaces <NUM>, <NUM> are cylindrical in shape with depressions <NUM>, <NUM> formed therein.

Between the surfaces <NUM>, <NUM> there is provided a button array <NUM>. The button array <NUM> comprises a horn button <NUM>, and a left and right indicator button <NUM>, <NUM>.

The driving controls are connected and operate as follows.

The user grips the second portions <NUM>, <NUM> of the arms <NUM>, <NUM> and as such can position his or her thumbs on one or both of the control surfaces <NUM>, <NUM> and buttons <NUM>, <NUM>, <NUM>. The thumbs rest in the depressions <NUM>, <NUM> and allow the user to rotate the member <NUM> forwards and rearwards. The member <NUM> is resiliently biased towards the neutral position. Rotation forwards about the axis CA causes power to be delivered from the battery to the wheel motors to accelerate the scooter. Releasing the member <NUM> will cause the scooter to freewheel, and reversing the direction of rotation (i.e. downwards) will cause braking by harvesting electrical energy from the wheel motor (i.e. acting as generators and charging the battery).

The user also has the ability to depress the horn <NUM> and left and right indicators <NUM>, <NUM> using their thumbs. Because the two surfaces <NUM>, <NUM> rotate together, the user only needs to keep one thumb engaged and can either rest the other, or use it to depress one of the other buttons.

Referring to <FIG>, the tiller <NUM> is supported by a spine <NUM> that extends from a mounting formation <NUM> at a first end for mounting to the tiller mount <NUM>, via an elongate U-shaped section <NUM> to a first arm <NUM> and a second arm <NUM> forming a "Y" shaped spine. The arms <NUM>, <NUM> extend into the first portions <NUM>, <NUM> of the arms <NUM>, <NUM> of the control assembly. The spine <NUM> is provided within the interior of the tiller, and is generally a unitary component. It is therefore stiff, and can react both the bending loads placed on the tiller by the user's hands, as well as transmit the steering torque required during riding.

<FIG> show the front wheel suspension and steering assembly <NUM>.

The assembly can be separated into the following parts:.

The central boss <NUM> is shown in detail in <FIG>. It is a unitary component constructed from metal. The boss <NUM> comprises a central cylindrical portion <NUM> having a through-bore <NUM> defining a deck pivot axis DPA oriented in a longitudinal direction (parallel to axis X).

Referring to <FIG>, a lower suspension attachment portion <NUM> is provided directly below the central cylindrical portion <NUM>. The portion <NUM> comprises a left-hand lower suspension attachment bore <NUM> and a right-hand lower suspension attachment bore <NUM>. The bores <NUM>, <NUM> are offset from each other and parallel with the deck pivot axis DPA and longitudinal axis X. Grub screw bores are provided in communication with, and perpendicular to, the bores <NUM>, <NUM>, extending from a lower surface of the portion <NUM> (not shown).

Extending below, and rearwardly of the central cylindrical portion <NUM> there is provided a deck support portion <NUM>. The deck support portion <NUM> comprises a pair of lower suspension attachment bores <NUM>, <NUM> directly opposite and aligned with the lower suspension attachment bores <NUM>, <NUM> respectively of the lower suspension attachment portion <NUM>. Only the left hand lower suspension attachment bore <NUM> is visible in <FIG>.

The deck support portion <NUM> further defines a deck mount bearing surface <NUM>, which is shaped as a concave, part-cylindrical surface. On the left and right hand sides of the deck support portion <NUM> are provided respective anti-camber spring support wings <NUM>, <NUM>.

On the front surface of the boss <NUM>, directly above the central cylindrical portion <NUM>, extending into the boss <NUM> parallel to the deck pivot axis DPA there is provided a rotation-limiting slot <NUM>. The slot <NUM> is arcuate and centred on the deck pivot axis DPA.

On the rear surface of the boss <NUM>, directly above the central cylindrical portion <NUM>, and extending rearwardly parallel to the deck pivot axis DPA there is provided a rotation-limiting protrusion <NUM>.

An upper suspension attachment portion <NUM> is provided directly above the central cylindrical portion <NUM>. The portion <NUM> comprises a left-hand upper suspension attachment bore <NUM> and a right-hand upper suspension attachment bore <NUM>. The bores <NUM>, <NUM> are offset from each other and parallel with the deck pivot axis DPA and longitudinal axis X. They are directly above the respective lower suspension attachment bores <NUM>, <NUM>. Grub screw bores <NUM>, <NUM> are provided in communication with, and perpendicular to, the bores <NUM>, <NUM>, extending from an upper surface of the portion <NUM>.

Extending laterally either side of the portion <NUM> there are provided two parallel left-hand upper wishbone attachment flanges <NUM>, <NUM> and two parallel right-hand upper wishbone attachment flanges <NUM>, <NUM>. Each flange defines a respective wishbone attachment bore <NUM>, <NUM>, <NUM>, <NUM> respectively.

The left suspension assembly <NUM> and wheel <NUM> is shown in <FIG>. The left suspension assembly is of an independent double-wishbone configuration.

The assembly comprises a left wheel hub <NUM>, a left upper wheel pivot <NUM>, a left lower wheel pivot <NUM> a left upper wishbone <NUM>, a left lower wishbone <NUM> and a left spring-damper assembly <NUM>.

The left wheel hub <NUM> comprises a body <NUM> configured for rotational mounting of the left wheel <NUM> via a DC electric motor, which is nested inside the wheel itself. The DC electric motor is configured to impart a torque to the wheel <NUM> to drive the wheel in rotation about a front left wheel axis FLW.

The hub <NUM> further comprises a mudguard attachment flange <NUM> extending rearwardly for attachment of a mudguard <NUM>.

The left wheel hub comprises a steering kingpin receiving bore <NUM> extending vertically therethrough. Extending forward of the hub there is defined a steering arm <NUM> defining a vertical steering pin receiving bore <NUM>.

A rotation limiting pin lug <NUM> is defined protecting laterally inwardly from the hub <NUM> defining a pin receiving bore <NUM>.

The left upper wheel pivot <NUM> comprises a base portion <NUM> defining an arcuate slot <NUM>. A wishbone mounting lug <NUM> defining a pivot bore <NUM> projects upwardly from the base portion <NUM>.

The left lower wheel pivot <NUM> comprises a base portion <NUM>. A wishbone mounting lug <NUM> defining a pivot bore <NUM> projects downwardly from the base portion <NUM>.

The left upper wishbone <NUM> is a generally U-shaped member having a forward arm <NUM> and a rearward arm <NUM> with aligned pivot bores <NUM>, <NUM> defined at the free ends thereof. Opposite the free ends, a pivot receiving slot <NUM> is defined having a throughbore <NUM> intersecting.

The left lower wishbone <NUM> has a body portion <NUM>, a forward arm <NUM> and a rearward arm <NUM> with aligned pivot bores <NUM>, <NUM> defined at the free ends thereof. Opposite the free ends, a pivot receiving slot <NUM> is defined having a throughbore <NUM> intersecting. A spring-damper receiving opening <NUM> is provided in the body portion intersected by a throughbore <NUM>.

The left spring-damper assembly <NUM> is known in the art, and will not be described in detail, suffice to say that it comprises a first attachment lug <NUM> defining a bore <NUM> and a second attachment lug <NUM> defining a bore <NUM>. The spring-damper assembly <NUM> is of variable length, being compressible and resilient as known in the art. It also has damping characteristics.

The right suspension subassembly and wheel are a mirror image of the left suspension subassembly and left wheel, as described above. References to the parts will be made with the prime (')- for example right wheel hub <NUM>'. The right wheel <NUM> rotates about a right wheel rotation axis FRW, which in a neutral steering position is parallel with the left wheel rotation axis FLW.

The steering subassembly <NUM> comprises:.

The tiller pivot shaft <NUM> of the tiller assembly <NUM> is also shown.

The front deck mount <NUM> comprises a deck abutment surface <NUM> profiled to the underside of the deck <NUM>. Two spaced-apart alignment protrusions <NUM>, <NUM> extend from an upper edge of the front deck mount <NUM> such that they project vertically upwards (also see <FIG>). The deck mount <NUM> further comprises a shaft-receiving open bore <NUM> being generally horizontally oriented.

The tiller pivot <NUM> comprises a first portion <NUM> being generally vertical and cylindrical in form, having a pivot shaft bore <NUM> running therethrough and defining a tiller pivot axis TPA. At the upper end of the first portion there is defined an axially extending spring abutment protrusion <NUM>. Extending tangentially either side of the upper end of the first portion there are provided pivot limit abutments <NUM>, <NUM>. A deck pivot shaft <NUM> extends normal to the first portion <NUM> and is generally cylindrical with a profiled end <NUM>.

The left- and right-hand anti-camber spring assemblies <NUM>, <NUM> comprise compression springs.

The steering links <NUM>, <NUM> are mirror images of each other and are generally stiff and capable of transmitting compressive and tensile loads.

The centring assembly <NUM> comprises a steering hub <NUM>, a housing <NUM> and a torsion spring <NUM>.

The steering hub <NUM> is generally flat, defining a shaft opening <NUM> therethrough. Adjacent the shaft opening and projecting upwardly from the steering hub <NUM> there is provided an arcuate spring abutment <NUM>. Radially outward from the spring abutment <NUM> there is defined a slot <NUM>. Projecting downwardly from the steering hub <NUM> there is provided a steering lug <NUM>.

The housing <NUM> is generally concave defining a cavity, and a shaft opening <NUM> therethrough.

The torsion spring <NUM> comprising a first spring abutment <NUM> and a second spring abutment <NUM>.

The rear wheel assembly <NUM> is shown in <FIG>.

The rear wheel assembly comprises a rear wheel <NUM>, a rear wheel carriage <NUM>, rear deck mount <NUM>, and a brake subassembly <NUM>.

The rear wheel is generally known in the art and comprises a central bearing arrangement to facilitate rotation about a rear wheel axis RW.

The rear wheel carriage <NUM> is shown in more detail in <FIG>. The carriage comprises a rear fork <NUM>, a left hand cover <NUM> and a right hand cover <NUM>. The rear fork <NUM> is generally U-shaped and comprises a left arm <NUM>, a right arm <NUM> and a base portion <NUM>. Each arm <NUM>, <NUM> defines an axle receiving bore <NUM>, <NUM>. The base portion <NUM> defines two lower lugs <NUM>, <NUM> each defining a spring pin receiving bore <NUM>, <NUM>. The base portion <NUM> also defines a brake spring cavity <NUM> passing therethrough defining a spring abutment <NUM> and two spaced-apart brake pivot bores <NUM>, <NUM> on opposite walls thereof.

The rear deck mount <NUM> comprises a deck abutment surface <NUM> profiled to the underside of the deck <NUM>. The rear deck mount <NUM> further defines (referring to <FIG>) a mounting portion <NUM> defining two spaced-apart wheel carrier attachment lugs <NUM>, <NUM> defining respective bores <NUM>, <NUM>. Below the lugs <NUM>, <NUM> there are provided rear abutment arms <NUM>, <NUM> extending rearwardly. A spring-damper channel <NUM> is also defined forward of the mounting portion <NUM>. An extensible spring-damper <NUM> is provided.

The brake subassembly <NUM> is shown in <FIG> is comprises a wheel contacting brake member <NUM> in the form of a mudguard and a torsion spring <NUM>. The brake member <NUM> defines a curved, concave wheel contacting portion <NUM> and an attachment portion <NUM> extending outwardly therefrom at one end. The attachment portion <NUM> comprises two spaced apart walls <NUM>, <NUM> defining spring pin bores <NUM>, <NUM>. The torsion spring <NUM> comprises a first abutment <NUM> and a pair of second abutments <NUM>, <NUM> either side thereof.

The tiller has two positions as shown by contrasting <FIG> and <FIG>. Movement between these positions is enabled by the tiller pivot and folding subassembly <NUM>.

Starting at the position of <FIG>, rotation of the tiller is effected by firstly dropping the pedal <NUM> into the deployed position from <FIG>. This enables the user to place a foot onto the pedal <NUM> to thereby rotate the catch <NUM> in direction C1 (<FIG>). This rotates the abutment shaft <NUM> out of the way of the head <NUM> of the shaft <NUM>. This enables relative rotation of the tiller mount <NUM> about the folding axis FA, moving from <FIG> (dripping the tiller to the position of <FIG>).

The tiller is secured in position against the deck by attraction from a permanent magnet in the tiller attracting the locking plate <NUM> of the rear deck insert <NUM>. Alignment is ensured by engagement of the male alignment protrusions <NUM>, <NUM> of the deck with corresponding female recesses <NUM>, <NUM> on the tiller (<FIG>). Manual force is used to separate the tiller and deck to move back to the unfolded condition.

Referring to <FIG>, the left wheel hub <NUM> is generally vertically oriented in use, with the wheel <NUM> mounted thereto via the DC electric motor for rotation about the front left wheel rotation axis FLW. The mudguard <NUM> is attached to the mudguard attachment flange <NUM> so as to at least partially cover the wheel <NUM>.

A kingpin (not shown) is provided passing through the steering kingpin receiving bore <NUM>. The left upper wheel pivot <NUM> is attached to the upper end of the kingpin on an upper side of the left wheel hub <NUM>, and the left lower wheel pivot <NUM> connected to the lower end of the kingpin on the opposite, lower side of the left wheel hub <NUM>. The left wheel hub <NUM> can rotate about the kingpin (and the pivots <NUM>, <NUM>) about a front left wheel steering axis FLS. Rotation about the front left wheel steering axis FLS is limited to a predetermined range by abutment of a steering limiting pin (not shown) inserted into the pin receiving bore <NUM> of the hub <NUM> against the ends of the arcuate slot <NUM> in the left upper wheel pivot <NUM>.

The left upper wishbone <NUM> is mounted to the left upper wheel pivot <NUM> for relative rotation via a pivot pin engaged with the pivot bore <NUM> of the left upper wheel pivot <NUM> and the throughbores <NUM> of the left upper wishbone <NUM>. The mounting lug <NUM> sits in the pivot receiving slot <NUM> of the left upper wishbone <NUM>.

The left lower wishbone <NUM> is mounted to the left lower wheel pivot <NUM> for relative rotation via a pivot pin engaged with the pivot bore <NUM> of the left lower wheel pivot <NUM> and the throughbores <NUM> of the left lower wishbone <NUM>. The mounting lug <NUM> sits in the pivot receiving slot <NUM> of the left lower wishbone <NUM>.

The left spring-damper assembly <NUM> is mounted at a first end via the first attachment lug <NUM> to an inboard end of the left upper wishbone <NUM>, and via the second end via the second attachment lug <NUM> to an outboard end of the left lower wishbone <NUM>.

This assembly is attached to the central boss <NUM> as follows. The left upper wishbone <NUM> is mounted to the left hand side of the boss <NUM> by positioning the wishbone arms either side of the wishbone attachment flanges <NUM>, <NUM>. A pivot pin is passed through the aligned bores <NUM>, <NUM>, <NUM>, <NUM>. The left lower wishbone <NUM> is mounted to the left hand side of the boss <NUM> by positioning the wishbone arms either side of the lower suspension attachment portion <NUM>. A pivot pin is passed through the aligned bores <NUM>, <NUM>, <NUM>. The pivot pin extends into the lower suspension attachment bore <NUM> directly opposite and aligned with the lower suspension attachment bore <NUM>.

In this way, a double-wishbone suspension arrangement is formed to mount the left wheel to the boss <NUM>. The wheel <NUM> is able to move vertically up and down relative to the boss <NUM> by rotation of the wishbones <NUM>, <NUM>. Upward motion (i.e. downward motion of the vehicle deck) will resiliently extend the spring-damper <NUM> to provide suspension.

It will be understood that the right-hand wheel is mounted in the same way.

Comparing <FIG>, articulation of the front suspension is shown. In <FIG>, the suspension is in a neutral, unloaded position. The deck is level and all three wheels rest on a first level L1. Turning to <FIG>, the front wheels have been raised relative to the deck to a second, higher level L2. In doing so, both of the wheels <NUM>, <NUM> have caused the left and right suspension subassemblies <NUM>, <NUM> respectively to articulate. For example, with respect to the left suspension <NUM>, the upper and lower wishbones <NUM>, <NUM> have rotated in an anti-clockwise direction (viewing <FIG>) to become parallel to the horizontal plane. In doing so, the left spring-damper assembly <NUM> has resiliently compressed resulting in a damping force contrary to the direction of motion, and a resilient force acting to restore the wheel position to <FIG>. It will be noted that the steering links <NUM>, <NUM> have also rotated about their respective end mountings.

Referring to <FIG>, the deck pivot shaft <NUM> is inserted for rotation about the deck pivot axis DPA into the through-bore <NUM> of the boss <NUM> (<FIG>) to rotationally mount the tiller pivot <NUM>. The front deck mount <NUM> is attached to the end of the deck pivot shaft <NUM> and fixed thereto such that the deck mount <NUM> (and deck when attached) are pivotable about the horizontal deck pivot axis DPA relative to the boss <NUM>.

The rotational position of the deck mount <NUM> and tiller pivot <NUM> is resiled back to a neutral position by the use of the two anti-camber spring assemblies <NUM>, <NUM> that are positioned in compression between the respective anti-camber spring support wings <NUM>, <NUM> of the boss <NUM> at the lower ends, and the deck mount <NUM> at the upper ends.

The tiller pivot shaft <NUM> is mounted for rotation about the tiller pivot axis TPA in the pivot shaft bore <NUM> of the tiller pivot <NUM>. Also mounted on the tiller pivot shaft is the centring assembly <NUM>. The steering hub <NUM> and housing <NUM> encapsulate the torsion spring <NUM>. The centring assembly <NUM> is mounted for rotation with the tiller pivot. The centring assembly <NUM> has several functions. Firstly, the spring abutment protrusion <NUM> of the tiller pivot <NUM> is received in the slot <NUM> and acts as an abutment for either of the spring abutments <NUM>, <NUM>. When the tiller pivot shaft is rotated about the tiller pivot axis TPA, the separation of the (stationary) spring abutment protrusion and moving spring abutment <NUM> of the steering hub <NUM> acts to tension the spring, which tries to realign them. Secondly, the steering hub <NUM> acts as a rotation limit stop as at a predetermined rotational limit (in either direction), the steering lug <NUM> will abut either stationary pivot limit abutment <NUM>, <NUM>.

Referring to <FIG>, the steering links <NUM>, <NUM> are mounted for rotation about a vertical axis from the underside of the steering lug <NUM> of the steering hub <NUM>. The steering links <NUM>, <NUM> are both connected to the steering lug <NUM> at a respective first end, and to respective steering arms of the wheel hubs at a respective second end. Attachment to the steering hubs is via a pivot shaft engaged with the steering pin receiving bore <NUM> (for example on the arm <NUM> of the left hand hub).

As discussed above, the wheel hubs are rotatable about respective vertical steering axes. Therefore lateral movement of the steering lug either right or left will have the effect of rotating the wheels about their respective steering axes. Referring to <FIG> (which is a view from underneath the vehicle, with the lower wishbones removed), the horizontal distance F1 between the steering axes FLS, FRS is less than the distance F2 between the axes of rotation between the steering links <NUM>, <NUM> and the respective steering lugs <NUM>, <NUM>'. This provides so-called "Ackermann" steering- i.e. when the wheels are turned in a specific direction, the innermost wheel (closest to the centre of the turning circle) will rotate about the steering axis more than the outer wheel. In the present embodiment, F1 < F2 because the steering links are forward of the kingpins. It will be noted that if the steering links are rearward of the kingpins then F1 > F2 for Ackermann steering.

Such lateral movement of the steering lug <NUM> relative to the boss <NUM> (to which the suspension is attached) occurs in two ways, or steering modes:
The first mode is 'tiller rotation'. <FIG> show this. In <FIG> and <FIG>, the scooter <NUM> is in a neutral "wheels forward" position.

Rotation of the tiller assembly <NUM> with the rider's hands rotates the tiller pivot shaft about the tiller pivot axis TPA relative to the tiller pivot <NUM> and therefore the boss <NUM>. This rotates the steering hub <NUM> which causes sideways, arcuate motion of the steering lug <NUM> which acts to steer the wheels simultaneously. This motion can be viewed by comparing <FIG> and <FIG> and <FIG>. In particular, in <FIG>, the steering links <NUM>, <NUM> have been moved to the right (when viewed, or to the left from the rider's perspective) because they are attached to the lug <NUM> at a position offset from the tiller pivot axis TPA.

The second mode is 'deck roll'. <FIG> show this mode. Note that <FIG> show a section through the centre of the deck <NUM>. <FIG> show the scooter <NUM> in a neutral position.

In this mode, the deck <NUM> and therefore the deck mount <NUM> are rotated by the rider's feet (much like a skateboard or snowboard) such that rotation of the <NUM> and the deck tiller pivot <NUM> about the deck pivot axis DPA occurs (note that the deck pivot axis is shown in <FIG> for clarity). This causes sideways, arcuate motion of the steering lug <NUM> which acts to steer the wheels simultaneously about their respective steering axes FLS, FRS.

The above mechanism supports these modes either individually, or in combination. Crucially, both modes act to actuate the steering lug <NUM> which steers the wheels. It will be noted with reference to <FIG> that the horizontal distance between the tiller pivot axis TPA and the steering lug <NUM> is less than the vertical distance between the deck pivot axis DPA and the steering lug <NUM>.

The rear wheel <NUM> is mounted for rotation about the rear wheel axis RW between the arms <NUM>, <NUM> of the rear fork <NUM>. The entire rear wheel carriage <NUM> (of which the fork <NUM> is a part) is mounted to the rear deck mount <NUM> for rotation about a rear wheel suspension axis RWS. The spring-damper <NUM> is nested within the spring-damper channel <NUM>, attached to the rear deck mount <NUM> at a first end and to the fork <NUM> at a second end (specifically via the spring spin receiving bores <NUM>, <NUM>).

Downward pressure on the deck <NUM> relative to the wheel <NUM> (or conversely upward force on the wheel <NUM> relative to the deck <NUM>) causes the wheel carriage <NUM> to rotate in a clockwise sense about the rear wheel suspension axis RWS when viewed in <FIG>. This acts to extend the spring-damper <NUM> which provides a damping force against the motion, as well as a resilient spring force to try and restore the neutral position of the rear wheel.

The rear brake <NUM> can be depressed against the rear wheel <NUM> against the bias of the spring <NUM> to provide a frictional braking force as known in the art. This is generally used as an "emergency" brake, as most braking is carried out by reverse-driving the front wheel motors to recover energy into the batteries.

Turning to <FIG>, a second scooter <NUM> is shown in accordance with the present invention. For the purposes of the present disclosure it is useful to define global directions and axes as follows:.

The scooter <NUM> comprises a deck assembly <NUM>, a tiller assembly <NUM>, a front wheel suspension and steering assembly <NUM> and a rear wheel assembly <NUM>.

The second embodiment is identical to the first embodiment with the exception of the rear wheel assembly <NUM>. As such, reference numerals relating to the deck assembly <NUM>, tiller assembly <NUM>, and the front wheel suspension and steering assembly <NUM> features will be numbered per the scooter <NUM>, but <NUM> greater.

<FIG> show the rear wheel suspension and steering assembly <NUM>.

Turning to <FIG>, the mounting subassembly <NUM> comprises a rear deck mount <NUM>, a rear boss <NUM>, a deck pivot shaft <NUM> and left and right anti-camber springs <NUM>, <NUM>.

The deck mount <NUM> comprises a deck abutment surface <NUM> profiled to the underside of the deck <NUM>. The rear deck mount <NUM> further defines a deck pivot shaft opening <NUM> extending in a generally longitudinal direction along the deck pivot axis DPA. The deck mount <NUM> further defines two downwardly-facing camber spring attachment points <NUM>, <NUM>.

The rear boss <NUM> comprises a pivot shaft throughbore <NUM> extending along the deck pivot axis DPA. It also defines two spaced-apart upwardly-facing camber spring attachment points <NUM>, <NUM>, either side of the axis DPA. The boss <NUM> defines a lower wishbone attachment lug <NUM>, an upper wishbone attachment lug <NUM> and two spaced apart spring-damper attachment flanges <NUM>, <NUM>, <NUM>, <NUM> on either side of the upper wishbone attachment lug <NUM>.

The deck pivot shaft <NUM> is generally hollow and cylindrical having a tapered front end <NUM>, and a flat rear end <NUM> into which a plug <NUM> is inserted.

Turning to <FIG>, the left suspension subassembly <NUM> is shown. The left suspension subassembly <NUM> is of an independent double-wishbone configuration. The assembly comprises a left wheel hub <NUM>, a left upper wheel pivot <NUM>, a left lower wheel pivot <NUM> a left upper wishbone <NUM>, a left lower wishbone <NUM> and a left spring-damper assembly <NUM>.

The left wheel hub <NUM> comprises a body <NUM> configured for rotational mounting of the left wheel <NUM> about a rear left wheel axis RLW. The body <NUM> defines a steering arm <NUM> extending rearwardly therefrom.

The pivots <NUM>, <NUM> are mounted above and below the body <NUM> and joined by a steering kingpin for rotation relative thereto about a rear left wheel steering axis RLS.

The upper, lower wishbones <NUM>, <NUM> and spring damper assembly <NUM> are similar to those on the front suspension and will not be described in detail.

The right suspension subassembly and wheel are a mirror image of the left suspension subassembly and left wheel, as described above. References to the parts will be made with the prime (')- for example right wheel hub <NUM>'. The right wheel <NUM>' rotates about a right wheel rotation axis RRW, which in a neutral steering position is parallel with the left wheel rotation axis RLW.

Referring to <FIG>, the deck pivot cam <NUM> is a generally flat plate having a pivot shaft receiving formation <NUM>, and an eccentric portion <NUM> comprising a first set of link openings <NUM> at a first radius r1 from the deck pivot axis DPA and a second set of link openings <NUM> at a second, greater radius from the deck pivot axis DPA.

The left and right hand steering links <NUM>, <NUM> comprise respective ball joints <NUM>, <NUM> at a medial end and respective ball joints <NUM>, <NUM> at a lateral end.

Referring to <FIG>, the deck pivot shaft <NUM> is attached to the deck mount <NUM> by attachment inside the opening <NUM>. It is then inserted into the throughbore <NUM> in the boss <NUM> such that the deck mount <NUM> (and deck <NUM> attached thereto) can rotate about the deck pivot axis DPA.

The relative rotation between the deck mount <NUM> and the boss <NUM> is controlled by the two anti-camber springs <NUM>, <NUM> extending between the points <NUM>, <NUM> and <NUM>, <NUM> respectively. As such, the mount <NUM> and boss <NUM> are resiliently biased to a neutral position (per <FIG>).

The left and right suspension subassemblies <NUM>, <NUM> are attached to the boss <NUM>. The upper wishbones <NUM>, <NUM>' are attached to the upper wishbone lug <NUM>, and the lower wishbones <NUM>, <NUM>' attached to the lower wishbone lug <NUM>. The wishbones are mounted for rotation relative to the boss about axes parallel to the direction of travel X.

The spring-damper assemblies <NUM>, <NUM>' are positioned to extend between the spring damper attachment flanges <NUM>, <NUM>, <NUM>, <NUM> of the boss <NUM> and the lower wishbones <NUM>, <NUM>'.

The deck pivot cam <NUM> is mounted to rotate with the shaft <NUM>, on the opposite side of the boss <NUM> to the deck <NUM>. The steering links <NUM>, <NUM> extend in opposite directions from the second set of link openings <NUM> to the upper side of the steering arms <NUM>, <NUM>' on each respective hub <NUM>, <NUM>'.

Comparing <FIG>, articulation of the rear suspension is shown. In <FIG>, the suspension is in a neutral, unloaded position. The deck is level and all four wheels rest on a first level L1. Turning to <FIG>, the rear wheels have been raised relative to the deck to a second, higher level L2. In doing so, both of the wheels <NUM>, <NUM> have caused the left and right suspension subassemblies <NUM>, <NUM> respectively to articulate. For example, with respect to the left suspension <NUM>, the upper and lower wishbones <NUM>, <NUM> have rotated in a clockwise direction (viewing <FIG>) to become parallel to the horizontal plane (<FIG>). In doing so, the left spring-damper assembly <NUM> has resiliently compressed resulting in a damping force contrary to the direction of motion, and a resilient force acting to restore the wheel position to <FIG>. It will be noted that the steering links <NUM>, <NUM> have also rotated about their respective end mountings.

The rear steering capability is responsive to deck roll only (unlike the front wheels that are responsive to deck roll and tiller pivot). Comparing <FIG>, rotation of the deck in a clockwise direction about the deck pivot axis DPA rotates the deck pivot shaft <NUM> in the boss <NUM> against the bias of the anti-camber springs <NUM>, <NUM>. It will be noted from above, that this lean to the right (in the direction of travel) causes the front wheels to rotate to steer to the right (i.e. in a clockwise direction about their respective steering axes FLS, FRS in plan). Such motion acts to move the eccentric portion <NUM> of the deck pivot cam <NUM>. This also moves the steering links <NUM>, <NUM> to the right, to rotate the hubs <NUM>, <NUM>' (and therefore wheels) in an anti-clockwise direction in plan about the rear steering axes RLS, RRS. In other words, the rear wheels steer to the left. <FIG> shows the steering motion of the wheels <NUM>, <NUM> during board lean. <FIG> shows the wheel positions during the tiller pivot mode of steering- the rear wheels <NUM>, <NUM> are not affected by this mode, and remain forward facing.

Referring to <FIG>, (which is a view from underneath the vehicle, with the lower wishbones removed), the horizontal distance R1 between the steering axes RLS, RRS is less than the distance R2 between the axes of rotation between the steering links <NUM>, <NUM> and the respective steering lugs <NUM>, <NUM>'. This provides so-called "Ackermann" steering- i.e. when the wheels are turned in a specific direction, the innermost wheel (closest to the centre of the turning circle) will rotate about the steering axis more than the outer wheel. In the present embodiment, R1 < R2 because the steering links are forward of the kingpins. It will be noted that if the steering links are rearward of the kingpins then R1 > R2 for Ackermann steering.

Claim 1:
A scooter (<NUM>) comprising:
a deck (<NUM>) for a rider to stand on;
a tiller (<NUM>) projecting upwardly from the deck (<NUM>) in use;
two front wheels (<NUM>; <NUM>);
a steering mechanism (<NUM>) configured to steer the two front wheels(<NUM>; <NUM>) about respective steering axes; and,
at least one rear wheel (<NUM>);
characterised in that the steering system has:
a first mode of steering in which rotation of the tiller(<NUM>) about a vertical axis (TPA) steers the two front wheels (<NUM>; <NUM>) and,
a second mode of steering in which rotation of the deck(<NUM>) about a horizontal axis (DPA) steers the two front wheels (<NUM>; <NUM>).