Patent ID: 12258097

DETAILED DESCRIPTION

First Embodiment

FIGS.1ato1cand2bare various views of an entire electric scooter100according 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:Direction of forward travel along horizontal longitudinal axis X;Rotation about this axis is “roll”;Lateral direction along horizontal axis Y;Rotation about this axis is “pitch”;Vertical direction along vertical axis Z;Rotation about this axis is “yaw”.

The scooter100comprises a deck assembly102, a tiller assembly104, a front wheel suspension and steering assembly106and a rear wheel assembly108. ComparingFIGS.1ato1candFIGS.3aand3b, the scooter100can be moved from an unfolded condition where the deck102is on the ground with the tiller104normal thereto (upright) to a folded condition where the deck and tiller are parallel.

Structure of the First Embodiment

Deck Assembly102

Referring toFIG.4, the deck assembly102is shown.

The deck assembly102comprises a deck panel110having a front portion112, rear portion114and a central portion116. The front and rear portions112,114are defined by upturned, curved regions118,120respectively, extending at 45 degrees to the flat, planar central portion116. Each of the front and rear portions112,114are also narrower in the lateral direction than the central portion110, being tapered at the curved regions118,120. The deck panel110is constructed from a composite material to be lightweight and stiff (e.g. carbon fibre reinforced polymer).

The deck assembly102comprises a front deck insert122and a rear deck insert124. The deck inserts122,124are constructed from a metal material (so they are able to hold a thread) and embedded in the panel110with fixing holes126,128respectively being open to the surface of the deck assembly102. Each deck insert122,124extends through the respective curved region118,120.

The rear deck insert124comprises a locking plate125constructed from a ferromagnetic material.

Tiller Assembly104

FIGS.5ato5kshow the tiller104. The tiller104comprises:A tiller pivot and folding assembly130(FIGS.5bto5g);A battery assembly134(FIGS.5hand5i);A control assembly135(FIGS.5jand5k); and,A spine132(FIG.5l).

The tiller pivot and folding subassembly130is shown inFIGS.5bto5g. The assembly comprises a tiller pivot shaft138, a tiller mount348and a catch350.

The tiller pivot shaft comprises a main shaft portion342and a head344defining a tilt pivot shaft bore346(FIGS.5cand5g).

The tiller mount348is attached to the main part of the tiller, and moveable therewith. The tiller mount348is pivotably mounted to the tiller pivot shaft130via a tilt pivot shaft352which is engaged with the tilt pivot shaft bore346. This enables the tiller mount348(and tiller) to rotate about a folding axis FA.

The catch350comprises two spaced-apart plates either side of the tiller mount348. The catch350comprises a pedal354rotatable between a stowed position where is sits flush with the tiller mount348(FIG.5d) and a deployed position rotated 90 degrees to project approximately parallel with the deck. This enables a user's foot to actuate the pedal354. The catch350has a pivot pin356to enable rotation relative to the tiller mount348. The catch350further comprises an abutment shaft358(FIG.5c).

The battery assembly134is shown inFIGS.5dand5e. The battery assembly134comprises a tiller subassembly300and a battery module302. 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 module302is configured to be easily installed and removed in the base of the tiller. The module302comprises a lever304which can be lifted in direction L to release a mechanical locking mechanism to allow removal of the module302in direction BR. Replacement of the module302re-connects the electrical contact between the tiller subassembly300and the battery module302.

There are three types of battery module302with this particular embodiment:A travel pack (module302);A standard capacity pack; and,A high capacity pack.

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 module302, has a 320 Whr (Watt-hours) energy storage capacity. The pack302comprises a module carrier306, a first battery sub-module308and a second battery sub-module310. Each sub-module308,310has a capacity of 160 Whr. This means that the battery sub-modules308,310may be separate (e.g. by removing both from the carrier306) 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 assembly135is located at the uppermost part of the tiller (furthest from the deck in the unfolded condition) and is shown inFIGS.5gand5h. The control assembly comprises a base region312from which first and second arms314,316project vertically upwardly and outwardly at a first portion318,320respectively, upwardly and inwardly at a second portion322,324respectively and meeting a crossbar portion326joining the respective free ends. The control assembly therefore forms a hexagon shape.

A user interface328is provided mounted to the base region312and 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 crossbar326comprises the primary driving controls. An accelerator/brake control328is provided comprising a single rotatable control member330rotatable about a horizontal control axis CA (parallel to the crossbar326). The member330comprises two spaced-apart control surfaces332,334. One control surface332is proximate the left hand arm314, and another surface334proximate the right hand arm316. The surfaces332,334are cylindrical in shape with depressions336,338formed therein.

Between the surfaces332,334there is provided a button array340. The button array340comprises a horn button342, and a left and right indicator button344,346.

The driving controls are connected and operate as follows.

The user grips the second portions322,324of the arms314,316and as such can position his or her thumbs on one or both of the control surfaces332,334and buttons344,346,348. The thumbs rest in the depressions336,338and allow the user to rotate the member330forwards and rearwards. The member330is 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 member330will 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 horn348and left and right indicators344,346using their thumbs. Because the two surfaces332,334rotate 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 toFIG.5l, the tiller104is supported by a spine132that extends from a mounting formation364at a first end for mounting to the tiller mount348, via an elongate U-shaped section366to a first arm368and a second arm370forming a “Y” shaped spine. The arms368,370extend into the first portions318,320of the arms314,316of the control assembly. The spine132is 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.

Front Wheel Suspension and Steering Assembly106

FIGS.6ato6kshow the front wheel suspension and steering assembly106.

The assembly can be separated into the following parts:A central boss400(FIGS.6band6c);A left suspension subassembly402and left wheel404(FIGS.6dto6g);A right suspension subassembly406and right wheel408; and,A steering subassembly410(FIGS.6hto6k).
Central Boss400

The central boss400is shown in detail inFIGS.6band6c. It is a unitary component constructed from metal. The boss400comprises a central cylindrical portion412having a through-bore414defining a deck pivot axis DPA oriented in a longitudinal direction (parallel to axis X).

Referring toFIG.6b, a lower suspension attachment portion416is provided directly below the central cylindrical portion412. The portion416comprises a left-hand lower suspension attachment bore418and a right-hand lower suspension attachment bore420. The bores418,420are 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 bores418,420, extending from a lower surface of the portion416(not shown).

Extending below, and rearwardly of the central cylindrical portion412there is provided a deck support portion422. The deck support portion422comprises a pair of lower suspension attachment bores424,426directly opposite and aligned with the lower suspension attachment bores418,420respectively of the lower suspension attachment portion416. Only the left hand lower suspension attachment bore424is visible inFIG.6b.

The deck support portion422further defines a deck mount bearing surface428, which is shaped as a concave, part-cylindrical surface. On the left and right hand sides of the deck support portion422are provided respective anti-camber spring support wings430,432.

On the front surface of the boss400, directly above the central cylindrical portion412, extending into the boss400parallel to the deck pivot axis DPA there is provided a rotation-limiting slot434. The slot434is arcuate and centred on the deck pivot axis DPA.

On the rear surface of the boss400, directly above the central cylindrical portion412, and extending rearwardly parallel to the deck pivot axis DPA there is provided a rotation-limiting protrusion436.

An upper suspension attachment portion438is provided directly above the central cylindrical portion412. The portion438comprises a left-hand upper suspension attachment bore440and a right-hand upper suspension attachment bore442. The bores440,442are 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 bores424,426. Grub screw bores444,446are provided in communication with, and perpendicular to, the bores440,442, extending from an upper surface of the portion438.

Extending laterally either side of the portion438there are provided two parallel left-hand upper wishbone attachment flanges448,450and two parallel right-hand upper wishbone attachment flanges452,454. Each flange defines a respective wishbone attachment bore456,458,460,462respectively.

Left Suspension Subassembly402and Left Wheel404

The left suspension assembly402and wheel404is shown inFIGS.6dto6f. The left suspension assembly is of an independent double-wishbone configuration.

The assembly comprises a left wheel hub464, a left upper wheel pivot466, a left lower wheel pivot468a left upper wishbone470, a left lower wishbone472and a left spring-damper assembly474.

The left wheel hub464comprises a body476configured for rotational mounting of the left wheel402via a DC electric motor, which is nested inside the wheel itself. The DC electric motor is configured to impart a torque to the wheel404to drive the wheel in rotation about a front left wheel axis FLW.

The hub464further comprises a mudguard attachment flange478extending rearwardly for attachment of a mudguard480.

The left wheel hub comprises a steering kingpin receiving bore482extending vertically therethrough. Extending forward of the hub there is defined a steering arm484defining a vertical steering pin receiving bore486.

A rotation limiting pin lug488is defined protecting laterally inwardly from the hub464defining a pin receiving bore490.

The left upper wheel pivot466comprises a base portion492defining an arcuate slot494. A wishbone mounting lug496defining a pivot bore498projects upwardly from the base portion494.

The left lower wheel pivot468comprises a base portion500. A wishbone mounting lug502defining a pivot bore504projects downwardly from the base portion500.

The left upper wishbone470is a generally U-shaped member having a forward arm506and a rearward arm508with aligned pivot bores510,512defined at the free ends thereof. Opposite the free ends, a pivot receiving slot514is defined having a throughbore516intersecting.

The left lower wishbone472has a body portion518, a forward arm520and a rearward arm522with aligned pivot bores524,526defined at the free ends thereof. Opposite the free ends, a pivot receiving slot528is defined having a throughbore530intersecting. A spring-damper receiving opening532is provided in the body portion intersected by a throughbore534.

The left spring-damper assembly474is known in the art, and will not be described in detail, suffice to say that it comprises a first attachment lug536defining a bore538and a second attachment lug540defining a bore542. The spring-damper assembly474is of variable length, being compressible and resilient as known in the art. It also has damping characteristics.

Right Suspension Subassembly406and Right Wheel408

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 hub464′. The right wheel408rotates about a right wheel rotation axis FRW, which in a neutral steering position is parallel with the left wheel rotation axis FLW.

Steering Subassembly410

The steering subassembly410comprises:a front deck mount544;a tiller pivot546;a left-hand anti-camber spring assembly548;a right-hand anti-camber spring assembly550;a left-hand steering link552;a right hand steering link554;a left-hand steering link central pivot556(FIG.6k);a right-hand steering link central pivot558(FIG.6k);a centring assembly560(FIG.6j).

The tiller pivot shaft138of the tiller assembly104is also shown.

The front deck mount544comprises a deck abutment surface562profiled to the underside of the deck110. Two spaced-apart alignment protrusions563,565extend from an upper edge of the front deck mount544such that they project vertically upwards (also seeFIG.2a). The deck mount544further comprises a shaft-receiving open bore564being generally horizontally oriented.

The tiller pivot546comprises a first portion566being generally vertical and cylindrical in form, having a pivot shaft bore568running therethrough and defining a tiller pivot axis TPA. At the upper end of the first portion there is defined an axially extending spring abutment protrusion573. Extending tangentially either side of the upper end of the first portion there are provided pivot limit abutments575,577. A deck pivot shaft573extends normal to the first portion566and is generally cylindrical with a profiled end575.

The left- and right-hand anti-camber spring assemblies548,550comprise compression springs.

The steering links552,554are mirror images of each other and are generally stiff and capable of transmitting compressive and tensile loads.

The centring assembly560comprises a steering hub577, a housing579and a torsion spring581.

The steering hub577is generally flat, defining a shaft opening578therethrough. Adjacent the shaft opening and projecting upwardly from the steering hub572there is provided an arcuate spring abutment580. Radially outward from the spring abutment580there is defined a slot582. Projecting downwardly from the steering hub572there is provided a steering lug584.

The housing581is generally concave defining a cavity, and a shaft opening586therethrough.

The torsion spring576comprising a first spring abutment588and a second spring abutment590.

Rear Wheel Assembly108

The rear wheel assembly108is shown inFIGS.7ato7g.

The rear wheel assembly comprises a rear wheel700, a rear wheel carriage702, rear deck mount704, and a brake subassembly706.

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 carriage702is shown in more detail inFIG.7d. The carriage comprises a rear fork708, a left hand cover710and a right hand cover712. The rear fork708is generally U-shaped and comprises a left arm714, a right arm716and a base portion718. Each arm714,716defines an axle receiving bore720,722. The base portion718defines two lower lugs724,726each defining a spring pin receiving bore728,730. The base portion718also defines a brake spring cavity732passing therethrough defining a spring abutment734and two spaced-apart brake pivot bores736,738on opposite walls thereof.

The rear deck mount704comprises a deck abutment surface740profiled to the underside of the deck110. The rear deck mount704further defines (referring toFIG.7f) a mounting portion742defining two spaced-apart wheel carrier attachment lugs744,746defining respective bores748,750. Below the lugs744,746there are provided rear abutment arms752,754extending rearwardly. A spring-damper channel756is also defined forward of the mounting portion742. An extensible spring-damper708is provided.

The brake subassembly706is shown inFIG.7gis comprises a wheel contacting brake member758in the form of a mudguard and a torsion spring772. The brake member758defines a curved, concave wheel contacting portion760and an attachment portion762extending outwardly therefrom at one end. The attachment portion762comprises two spaced apart walls764,766defining spring pin bores768,770. The torsion spring772comprises a first abutment774and a pair of second abutments776,778either side thereof.

Assembly and Operation of the First Embodiment

Folding

The tiller has two positions as shown by contrastingFIGS.1aand3a. Movement between these positions is enabled by the tiller pivot and folding subassembly130.

Starting at the position ofFIG.1a, rotation of the tiller is effected by firstly dropping the pedal354into the deployed position fromFIGS.5dto5e. This enables the user to place a foot onto the pedal354to thereby rotate the catch350in direction C1(FIG.5e). This rotates the abutment shaft358out of the way of the head344of the shaft138. This enables relative rotation of the tiller mount348about the folding axis FA, moving fromFIGS.5eto5f(dripping the tiller to the position ofFIG.3a).

The tiller is secured in position against the deck by attraction from a permanent magnet in the tiller attracting the locking plate125of the rear deck insert124. Alignment is ensured by engagement of the male alignment protrusions563,565of the deck with corresponding female recesses360,362on the tiller (FIG.2a). Manual force is used to separate the tiller and deck to move back to the unfolded condition.

Front Suspension

Referring toFIGS.6dto6g, the left wheel hub464is generally vertically oriented in use, with the wheel404mounted thereto via the DC electric motor for rotation about the front left wheel rotation axis FLW. The mudguard480is attached to the mudguard attachment flange478so as to at least partially cover the wheel404.

A kingpin (not shown) is provided passing through the steering kingpin receiving bore482. The left upper wheel pivot466is attached to the upper end of the kingpin on an upper side of the left wheel hub464, and the left lower wheel pivot468connected to the lower end of the kingpin on the opposite, lower side of the left wheel hub464. The left wheel hub464can rotate about the kingpin (and the pivots466,468) 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 bore490of the hub464against the ends of the arcuate slot494in the left upper wheel pivot466.

The left upper wishbone470is mounted to the left upper wheel pivot466for relative rotation via a pivot pin engaged with the pivot bore498of the left upper wheel pivot466and the throughbores516of the left upper wishbone470. The mounting lug496sits in the pivot receiving slot514of the left upper wishbone470.

The left lower wishbone472is mounted to the left lower wheel pivot468for relative rotation via a pivot pin engaged with the pivot bore504of the left lower wheel pivot468and the throughbores530of the left lower wishbone472. The mounting lug502sits in the pivot receiving slot528of the left lower wishbone472.

The left spring-damper assembly474is mounted at a first end via the first attachment lug536to an inboard end of the left upper wishbone470, and via the second end via the second attachment lug540to an outboard end of the left lower wishbone472.

This assembly is attached to the central boss400as follows. The left upper wishbone470is mounted to the left hand side of the boss400by positioning the wishbone arms either side of the wishbone attachment flanges448,450. A pivot pin is passed through the aligned bores460,462,510,512. The left lower wishbone472is mounted to the left hand side of the boss400by positioning the wishbone arms either side of the lower suspension attachment portion416. A pivot pin is passed through the aligned bores418,510,512. The pivot pin extends into the lower suspension attachment bore424directly opposite and aligned with the lower suspension attachment bore418.

In this way, a double-wishbone suspension arrangement is formed to mount the left wheel to the boss400. The wheel404is able to move vertically up and down relative to the boss400by rotation of the wishbones470,472. Upward motion (i.e. downward motion of the vehicle deck) will resiliently extend the spring-damper474to provide suspension.

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

ComparingFIGS.8aand8b, articulation of the front suspension is shown. InFIG.8a, the suspension is in a neutral, unloaded position. The deck is level and all three wheels rest on a first level L1. Turning toFIG.8b, the front wheels have been raised relative to the deck to a second, higher level L2. In doing so, both of the wheels404,408have caused the left and right suspension subassemblies402,406respectively to articulate. For example, with respect to the left suspension402, the upper and lower wishbones470,472have rotated in an anti-clockwise direction (viewingFIG.8a) to become parallel to the horizontal plane. In doing so, the left spring-damper assembly474has resiliently compressed resulting in a damping force contrary to the direction of motion, and a resilient force acting to restore the wheel position toFIG.8a. It will be noted that the steering links552,554have also rotated about their respective end mountings.

Steering

Referring toFIG.6j, the deck pivot shaft570is inserted for rotation about the deck pivot axis DPA into the through-bore414of the boss400(FIGS.6band6c) to rotationally mount the tiller pivot546. The front deck mount544is attached to the end of the deck pivot shaft570and fixed thereto such that the deck mount544(and deck when attached) are pivotable about the horizontal deck pivot axis DPA relative to the boss400.

The rotational position of the deck mount544and tiller pivot546is resiled back to a neutral position by the use of the two anti-camber spring assemblies548,550that are positioned in compression between the respective anti-camber spring support wings430,432of the boss400at the lower ends, and the deck mount544at the upper ends.

The tiller pivot shaft138is mounted for rotation about the tiller pivot axis TPA in the pivot shaft bore568of the tiller pivot546. Also mounted on the tiller pivot shaft is the centring assembly560. The steering hub572and housing574encapsulate the torsion spring576. The centring assembly560is mounted for rotation with the tiller pivot. The centring assembly560has several functions. Firstly, the spring abutment protrusion573of the tiller pivot546is received in the slot582and acts as an abutment for either of the spring abutments588,590. When the tiller pivot shaft is rotated about the tiller pivot axis TPA, the separation of the (stationary) spring abutment protrusion and moving spring abutment580of the steering hub572acts to tension the spring, which tries to realign them. Secondly, the steering hub572acts as a rotation limit stop as at a predetermined rotational limit (in either direction), the steering lug584will abut either stationary pivot limit abutment575,577.

Referring toFIG.6h, the steering links552,554are mounted for rotation about a vertical axis from the underside of the steering lug584of the steering hub572. The steering links552,554are both connected to the steering lug584at 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 bore486(for example on the arm484of 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 toFIG.6l(which is a view from underneath the vehicle, with the lower wishbones removed), the horizontal distance F1between the steering axes FLS, FRS is less than the distance F2between the axes of rotation between the steering links552,554and the respective steering lugs584,584′. 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<F2because the steering links are forward of the kingpins. It will be noted that if the steering links are rearward of the kingpins then F1>F2for Ackermann steering.

Such lateral movement of the steering lug584relative to the boss400(to which the suspension is attached) occurs in two ways, or steering modes:

The first mode is ‘tiller rotation’.FIGS.9ato9dshow this. InFIGS.9aand9b, the scooter100is in a neutral “wheels forward” position.

Rotation of the tiller assembly104with the rider's hands rotates the tiller pivot shaft about the tiller pivot axis TPA relative to the tiller pivot546and therefore the boss400. This rotates the steering hub572which causes sideways, arcuate motion of the steering lug584which acts to steer the wheels simultaneously. This motion can be viewed by comparingFIGS.9aand9bto9cand9d. In particular, inFIG.9d, the steering links552,554have been moved to the right (when viewed, or to the left from the rider's perspective) because they are attached to the lug584at a position offset from the tiller pivot axis TPA.

The second mode is ‘deck roll’.FIGS.10ato10fshow this mode. Note thatFIGS.10cand10fshow a section through the centre of the deck110.FIGS.10ato10cshow the scooter100in a neutral position.

In this mode, the deck110and therefore the deck mount544are rotated by the rider's feet (much like a skateboard or snowboard) such that rotation of the110and the deck tiller pivot546about the deck pivot axis DPA occurs (note that the deck pivot axis is shown inFIG.9bfor clarity). This causes sideways, arcuate motion of the steering lug584which 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 lug584which steers the wheels. It will be noted with reference toFIG.6hthat the horizontal distance between the tiller pivot axis TPA and the steering lug546is less than the vertical distance between the deck pivot axis DPA and the steering lug546.

Rear Suspension

The rear wheel700is mounted for rotation about the rear wheel axis RW between the arms714,716of the rear fork708. The entire rear wheel carriage702(of which the fork708is a part) is mounted to the rear deck mount704for rotation about a rear wheel suspension axis RWS. The spring-damper780is nested within the spring-damper channel756, attached to the rear deck mount704at a first end and to the fork708at a second end (specifically via the spring spin receiving bores728,730).

Downward pressure on the deck110relative to the wheel700(or conversely upward force on the wheel700relative to the deck110) causes the wheel carriage702to rotate in a clockwise sense about the rear wheel suspension axis RWS when viewed inFIG.7b. This acts to extend the spring-damper780which 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 brake706can be depressed against the rear wheel700against the bias of the spring772to 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.

Second Embodiment

Turning toFIG.11, a second scooter1100is 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:Direction of forward travel along horizontal longitudinal axis X;Rotation about this axis is “roll”;Lateral direction along horizontal axis Y;Rotation about this axis is “pitch”;Vertical direction along vertical axis Z;Rotation about this axis is “yaw”.

The scooter1100comprises a deck assembly1102, a tiller assembly1104, a front wheel suspension and steering assembly1106and a rear wheel assembly1108.

Structure of the Second Embodiment

The second embodiment is identical to the first embodiment with the exception of the rear wheel assembly1108. As such, reference numerals relating to the deck assembly1102, tiller assembly1104, and the front wheel suspension and steering assembly1106features will be numbered per the scooter100, but 1000 greater.

Rear Wheel Assembly1108

FIGS.12ato12gshow the rear wheel suspension and steering assembly1108.

The assembly can be separated into the following parts:A mounting subassembly1800(FIGS.12bto12d);A left suspension subassembly1802and left rear wheel1804(FIG.12e);A right suspension subassembly1806and right rear wheel1808(FIG.12f); and,A steering subassembly1810(FIG.12g).
Mounting Subassembly1800

Turning toFIGS.12bto12d, the mounting subassembly1800comprises a rear deck mount1812, a rear boss1814, a deck pivot shaft1816and left and right anti-camber springs1818,1820.

The deck mount1812comprises a deck abutment surface1822profiled to the underside of the deck110. The rear deck mount1812further defines a deck pivot shaft opening1824extending in a generally longitudinal direction along the deck pivot axis DPA. The deck mount1822further defines two downwardly-facing camber spring attachment points1826,1828.

The rear boss1814comprises a pivot shaft throughbore1830extending along the deck pivot axis DPA. It also defines two spaced-apart upwardly-facing camber spring attachment points1832,1834, either side of the axis DPA. The boss1814defines a lower wishbone attachment lug1836, an upper wishbone attachment lug1838and two spaced apart spring-damper attachment flanges1840,1842,1844,1846on either side of the upper wishbone attachment lug1838.

The deck pivot shaft1816is generally hollow and cylindrical having a tapered front end1848, and a flat rear end1850into which a plug1852is inserted.

Left Suspension Subassembly1802and Left Rear Wheel1804

Turning toFIG.12e, the left suspension subassembly1802is shown. The left suspension subassembly1802is of an independent double-wishbone configuration. The assembly comprises a left wheel hub1854, a left upper wheel pivot1856, a left lower wheel pivot1858a left upper wishbone1860, a left lower wishbone1862and a left spring-damper assembly1864.

The left wheel hub1854comprises a body1866configured for rotational mounting of the left wheel1804about a rear left wheel axis RLW. The body1866defines a steering arm1868extending rearwardly therefrom.

The pivots1856,1858are mounted above and below the body1866and joined by a steering kingpin for rotation relative thereto about a rear left wheel steering axis RLS

The upper, lower wishbones1860,1862and spring damper assembly1864are similar to those on the front suspension and will not be described in detail.

Right Suspension Subassembly and Right Rear Wheel1808

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 hub1866′. The right wheel1804′ rotates about a right wheel rotation axis RRW, which in a neutral steering position is parallel with the left wheel rotation axis RLW.

Steering Subassembly

The steering subassembly1806comprises:a deck pivot cam1870;a left-hand steering link1872; and,a right hand steering link1874.

Referring toFIG.12g, the deck pivot cam1870is a generally flat plate having a pivot shaft receiving formation1876, and an eccentric portion1878comprising a first set of link openings1880at a first radius r1from the deck pivot axis DPA and a second set of link openings1882at a second, greater radius from the deck pivot axis DPA.

The left and right hand steering links1872,1874comprise respective ball joints1884,1886at a medial end and respective ball joints1888,1890at a lateral end.

Assembly and Operation of the Second Embodiment

Referring toFIGS.12bto12d, the deck pivot shaft1816is attached to the deck mount1812by attachment inside the opening1824. It is then inserted into the throughbore1830in the boss1814such that the deck mount1812(and deck110attached thereto) can rotate about the deck pivot axis DPA.

The relative rotation between the deck mount1812and the boss1814is controlled by the two anti-camber springs1818,1820extending between the points1826,1832and1828,1834respectively. As such, the mount1812and boss1814are resiliently biased to a neutral position (perFIG.12a).

The left and right suspension subassemblies1802,1806are attached to the boss1814. The upper wishbones1860,1860′ are attached to the upper wishbone lug1838, and the lower wishbones1862,1862′ attached to the lower wishbone lug1836. The wishbones are mounted for rotation relative to the boss about axes parallel to the direction of travel X.

The spring-damper assemblies1864,1864′ are positioned to extend between the spring damper attachment flanges1840,1842,1844,1846of the boss1814and the lower wishbones1862,1862′.

The deck pivot cam1870is mounted to rotate with the shaft1816, on the opposite side of the boss1814to the deck110. The steering links1872,1874extend in opposite directions from the second set of link openings1882to the upper side of the steering arms1868,1868′ on each respective hub1854,1854′.

ComparingFIGS.13aand13b, articulation of the rear suspension is shown. InFIG.13a, the suspension is in a neutral, unloaded position. The deck is level and all four wheels rest on a first level L1. Turning toFIG.13b, the rear wheels have been raised relative to the deck to a second, higher level L2. In doing so, both of the wheels1804,1808have caused the left and right suspension subassemblies1802,1806respectively to articulate. For example, with respect to the left suspension1802, the upper and lower wishbones1860,1860have rotated in a clockwise direction (viewingFIG.13a) to become parallel to the horizontal plane (FIG.13b). In doing so, the left spring-damper assembly1864has resiliently compressed resulting in a damping force contrary to the direction of motion, and a resilient force acting to restore the wheel position toFIG.13a. It will be noted that the steering links1872,1874have 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). ComparingFIGS.14aand14b, rotation of the deck in a clockwise direction about the deck pivot axis DPA rotates the deck pivot shaft1816in the boss1814against the bias of the anti-camber springs1818,1820. 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 portion1878of the deck pivot cam1870. This also moves the steering links1872,1874to the right, to rotate the hubs1854,1854′ (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.14cshows the steering motion of the wheels1804,1808during board lean.FIG.14dshows the wheel positions during the tiller pivot mode of steering—the rear wheels1804,1808are not affected by this mode, and remain forward facing.

Referring toFIG.14e, (which is a view from underneath the vehicle, with the lower wishbones removed), the horizontal distance R1between the steering axes RLS, RRS is less than the distance R2between the axes of rotation between the steering links1872,1874and the respective steering lugs1868,1868′. 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<R2because the steering links are forward of the kingpins. It will be noted that if the steering links are rearward of the kingpins then R1>R2for Ackermann steering.

Adjustment of the Rear Steering of the Second Embodiment

The rear steering subassembly1810can be adjusted to provide a different level of rear steering assistance to the rider. ComparingFIGS.15aand15b,FIG.15ais configured as above—i.e. with the steering links1872,1874extending in opposite directions from the second set of link openings1882to the upper side of the steering arms1868,1868′ on each respective hub1854,1854′. InFIG.15b, the links1872,1874have been removed and replaced extending in opposite directions from the first set of link openings1880to the lower side of the steering arms1868,1868′ on each respective hub1854,1854′. The lower radius of the first openings1880means that rotation of the deck will provide a much lower degree of movement for the links1872,1874thus producing a lesser rear steer effect. This is useful for e.g. beginners, and those who are less interested in “carving” turns with the deck lean mode of steering.