GB2511917A - Laid back cycle - Google Patents

Abstract

A cycle with discrete steering input and output axes 18 configured for rearward extended reach of a steering input control 12 and elevated presentation toward or juxtaposed with a rear seat 11. There may be a drive pedal crank axis at a similar longitudinal position to the steering input 12, forward of the rear seat 11. The steering drive transmission may be articulated between the input and output axes, and may have a plurality of couplings and shafts, providing relative transposition of the steering input axis to the steering output axis. The aim of the invention is to provide a semi-recumbent cycle wherein the cyclist has a laid back riding stance and a low centre of gravity CoG to provide ride comfort and balance, without having to lean forward or transfer weight when checking their peripherals, but also without compromising on the steering flexibility found with conventional aligned-axis steering methods.

Description

Laid Back Cycle This invention relates to cycles, or bicycles' with two or more wheels, particularly but not exclusively so-called street' bikes; configured for urban, commuter or sport utility use and where comfort, stability, visibility and safety are important if not paramount considerations.

The term cycle' is used for convenience to embrace diverse wheel configurations, including two wheeled, or bicycle, and three-wheeled, or tricycle, whether with paired wheels at front or rear, folding, manually-propelled or say electric power assisted. A rider sits between longitudinally spaced forward and rearward wheels of similar sizes and steers with a front wheel while driving a rear wheel through intermediate foot pedals.

In the evolution of cycle development diverse configurations and formats have been tried, but have generally evolved into a so-called safety format of braced diamond lattice frame, carrying a rear seat, a forward steering with transverse handle bars and intermediate lower drive pedals, so a seated rider can readily reach the ground. An inclined steerable front wheel carrier fork steering axis has also been adopted, with some modest variation in diagonal slant or rake angle. This rake and coincidence of input and output axes helps bring a steering input control, typically handlebars somewhat closer back towards a rearward seated rider. It also has an effect upon the steerable wheel pivot behaviour in relation to the frame and a tipping and turning response of the pivoted wheel to frame sideways lean or tilt. It has implications in forward weight shift and balance.

Some early cycles, such as the Rover, Starley and Humber models, featured rearward offset or dog leg steering drive coupling, but with an upright steerable front wheel axis.

Forward steering has traditionally required a rider to lean and reach forward from a rearward seat disposition, bringing upper trunk, arms and head forward and lower with emphasis upon looking forward and downward. Latterly, remote steering drives with translated input have been devised, along with upper hand or foot crank drives transferred to the steering for certain specialist categories, such as recumbents of semi-recumbents and twin rear wheel tricycle formats. Similarly, rear wheel steering has been tried, front wheel steering with lower foot pedal drive remains predominant.

A closed triangulated braced frame tube format is traditional for inherent stiffness, rigidity and self-bracing under rider weight load transfer to front and rear wheels, along with open-frame variants. Frame materials are commonly of steel or lighter alloys, with on occasion exotic materials such as titanium. Latterly fibre reinforced plastics materials, such as carbon fibre have been adopted to save weight whilst preserving strength. Span, disposition and orientation of frame members relate to rider stance for certain ride/drive pedal thrust actions. The Applicants envisage an open frame format configured to reflect a departure from convention in steering, pedal drive and seating disposition and geometry. In particular, a variation of relative disposition of seat, steering, drive and rider positions with a high upright seating stance combined with an extended reach steering input without having to lean forward. This along with a pedals forward of seat disposition.

A high and upright seating stance is advantageous for rider vision and visibility for other road users, but is not always conducive to looking out for traffic not immediately ahead.

Whether through habit, convenience or constraint of frame format, cyclists have limited awareness of other road users, in particular other traffic in close proximity immediately to one side or behind. A facility readily to look sideways and/or behind without inadvertent steering input, unsettling or unbalancing the ride would promote safety and stability. A conventional lean forward handlebar disposition is not conducive to this.

Although a rider cannot be compelled to look to one side or behind, and may be reluctant to do so for fear of reduced stability or control in doing so, some facility, encouragement, reassurance or incentive to do so could be engendered with confidence that looking to one side or behind is readily accomplished while keeping hands on steering, and in particular with no tendency to impart inadvertent steering inputs from body movement arising from looking to one side and behind. Certain aspects of the invention address this feature.

A steering input plane can remain generally orthogonal to a riders outstretched forearms or the arms can hang upward or downward somewhat, as when handling a vehicle steering wheel, with arms bent rather than fully outstretched. A steering input control can be contained in a steering input plane, in turn commonly orthogonal to a steering input axis, but an inclination or tilt of the input control plane can be used.

Access, reach, lean, tilt, stance and mass disposition and so weight distribution for a rider and steering control are inter-related issues for cycle control. The height of the centre of gravity (c of g) affects the sideways tip-over tendency of a cycle upon front wheel turn. The longitudinal position of the c of g affects the steering weighting and balance of front and rear wheel traction when ridden. A conventional cycle, such as of established diamond braced frame, or so-called safety' format requires a rider to lean forward to apply some weight upon a steering input control. This rider body-forward lean' loads or weights the steering input control with some inertia and feel as the frictional ground contact is enhanced by the weight transfer and tyre grip or traction.

The steering input control can also be gripped to help brace a rider body against a downward leg push action on the drive pedals. A rider upper body is upright but leans forward. An upright rider body stance can be made more extreme by a rider lifting up from the seat and putting all the rider weight in turn upon the pedals to apply more downward thrust than can be achieved when seated. The seat is no longer required to brace a forward component of the pedal thrust. A side to side sway action may also be adopted to put shift upon each pedal in turn The handle bars also have an important longitudinal and lateral balance role with the possibility of even greater weight applied for directional stability and control.

This stance is familiar to most riders and contributes stability and reassurance by applying weight over a steerable front wheel through a diametrically opposed steering input control, typically handle bars. A transverse steering bar with handle grips at opposite ends about an intervening coincident' steering input and output axis by opposite rider arms allows a rider to dampen and dictate steering input.

with leverage action reflecting the bar span about the steering axis. In a conventional steering geometry the steering input and output axes are coincident, but the Applicants envisage an offset between the two to allow the input to be brought back to wards a rearward seated rider without having to reach or lean unduly forward if at all. That same weight-lean stance however constrains and constricts a rider in looking to one side, behind or around.This in turn curtails a rider's situational awareness and presents a road safety hazard.

A lean forward rider stance has been developed in sports bikes with a pedal drive and traction agenda into a pronounced crouch or hunch over a steering input control, which can be minimal residual side stub bars upon front forks. There are some similarities with motor cycles. At an opposite extreme, a more relaxed, figuratively or literally, laid back' frame style has evolved, in so-called recumbent' and semi-recumbent' configurations with a rider's legs well forward outstretched from a seat with back rest. Forward leg thrust thus substitutes for downward thrust of a conventional upright frame and is braced by a seat back. A front steerable wheel is remote from a rider's arms and a rearward drive extension is commonly used. In a so-called chopper' motorcycle, a frame configured with an extreme acute angled front fork backward lean or rake presenting handlebars rearward has been adopted as an extreme style, but is not without handling stability and control issues. A chopper style has also been adopted for bicycles. A rider seat back rest for rider lean-back support while steering promotes a relaxed, so-called street cruiser' riding style. Handlebars are presented upward and backward for ease of rider hand-hold without lean. The severity of steering axis inclination adversely affects stability and control.

The Applicants envisage transposing a front wheel steering input control rearward and upward, closer to a rider's arms and hands input control, but without a rider having to lean forward to transfer rider weight upon the control, and in doing so freeing up rider mobility without detriment to balance. Such a steering input control can influence balance differently. Access to forward steering from a remote rearward seated rider would be an example implementation of this. The steering would be brought back from a steerable front ground wheel and presented rearwardly closer to a seated rider. The steerable front wheel or output axis could be undisturbed, but the steering input axis would be re-disposed and/or reorientated. This can be achieved by mounting a steering input control upon a rearward and optionally also upward extension from a front fork steering top' tube or carrier stem, in which are fitted longitudinally spaced bearings defining a front wheel steering or steering output axis. That is the frame extends rearward, and optionally also upward, beyond the front wheel steering output axis and carries an outboard bearing for a steering input control. This along with an inboard bearing can define a steering input axis. A steering transmission between a steering input and output can be routed indirectly, such as through a series of articulated shafts and intervening couplings. Desirably, the couplings are with Hook type universal joints or a convoluted torque tube configured to give a constant angular acceleration or constant velocity effect.

For control purposes, a front wheel carrier fork turning axis can be regarded as a steering output axis. The Applicants envisage that the steering input and output axes can be relatively displaced or offset angularly, without undermining steering action or sTability. An in appropriate steering input and so output acTion can induce tip over and lean. Similarly, or conversely, a frame lean or tip to one side can induce a turn tendency, albeit perversely to the opposite side. For cycle control a ridor must contond with both stooring and tip or loan inputs having rospoctivoly an associated secondary tip or turn effect. The respective centres of gravity of the cycle and rider contribute a turning moment when to the side of a ground contact point of the cycle, or indeed the rider. Inadvertent rider corrective, restorative or directive input of either kind, even when trying to straighten up or balance evenly, can induce an unexpected and unsettling effect, which a rider then has to counter appropriately and promptly, as beyond a certain point, the upset's are not restorable readily if at all time before the bicycle strikes the ground.

In one construction the Applicants propose a bearing for a steering output axis a transition br an offseT steering input axis.

In a conventional cycle the steering input and output axes are coincident or closely aligned. Various steering input controls from bars, through yokes to wheels could be carried on the end of the reorientated steering input axis. With an appropriately orientated steering input plane, such as one presented orthogonal to a riders arms, steering without forward lean allows a rider to look behind, to the side and around, without inadvertently imparting steering input through rider trunk, shoulder or arm movement. This obviates a distraction of uncommanded turn and tip and so helps raise rider situational awareness while steering whilst preserving stability.

Access, reach, lean, tilt, stance and mass disposition for a rider and steering control are inter-related issues for cycle control. A conventional cycle, such as of established diamond or splayed diagonal tubular element braced frame, between saddle, pedal crank and steering head at apices of a triangle, allows a rider sit above, behind and within leg span the pedal crank axis and to lean forward to apply some weight upon a steering input control. This so-called safety' format allows a stationary seated riders feet to rest individually in turn upon the ground with modest sideways frame lean or tilt.

Rider body forward lean loads or weights the steering with some inertia and associated resistance, reaction bite or feel as the frictional ground contact is enhanced by the weight transfer and tyre grip or traction. This stance is familiar to most riders and contributes stability and reassurance by applying weight over a steerable front wheel through a diametrically opposed steering input control, typically handle bars.The seat is somewhat to the rear close to over a rear wheel and so the overall weight distribution and c of g is rearward of mid -longitudinal span. This is countered with a lean forward stance over the front handlebars, as the conventional primary steering input control. A change in stance has an impact upon weight distribution and so must be managed judiciously.

Unconventional formats place emphasis upon a forward rather than downward pedal thrust action places reliance upon a seat to brace the reaction forces, and in particular a sear back, such as is common upon recumbent and semi-recumbent cycle configurations.

A handle bar grip at opposite ends about an intervening coincident' steering input and output axis by opposite rider arms allows a rider to dampen and dictate steering input.

A weight-lean stance and associated crouched or hunched upper body or trunk however constrains and constricts a rider in looking to one side, behind or around. A head turn about a fixe trunk offers limited lateral vision. This in turn curtails a rider's situational awareness and presents a road safety hazard. A lean-forward rider stance has been developed in sports bikes with a pedal drive and traction agenda into a pronounced head down crouch or hunch over a steering input control, which can be minimal residual side stub bars upon front forks. There are some similarities in that regard with motor cycles. At an opposite extreme to racing bicycle formats, a more relaxed, figuratively or literally, laid back' frame style has evolved, in so-called recumbent' and semi-recumbent' configurations with a rider's legs well forward outstretched from a seat with back rest. A front steerable wheel is remote from a rider's arms and a rearward drive extension is used.

In a so-called chopper' motorcycle, a frame configured with an extreme acute angled front fork backward lean or rake presenting handlebars rearward has been adopted as an extreme style, but is not without handling stability and control issues. A chopper style has also been adopted for bicycles. A rider seat back rest for rider lean-back support while steering promotes a relaxed, so-called street cruiser' riding style. Handlebars are presented upward and backward for ease of rider hand-hold without lean. The severity of steering axis inclination adversely affects stability and control.

The Applicants envisage transposing a front wheel steering input control markedly rearward and upward, closer to a rider's arms and hands input control, but without extreme rake of steering output and without a rider having to lean forward to transfer rider weight upon the control, and in doing so freeing up rider mobility without detriment to balance.

Access to forward steering from a remote rearward seated rider would be an example implementation of this. The steering would be brought back from a steerable front ground wheel and presented rearwardly to a seated rider. The steerable front wheel or output axis could be undisturbed, but the steering input axis re-disposed and/or reorientated. This can be achieved by mounting a steering input control upon a rearward and optionally also upward extension from a front fork steering tube or carrier stem, in which are fitted longitudinally spaced bearings defining a front wheel steering or steering output axis. That is the frame extends rearward, and optionally also upward, beyond the front wheel steering output axis and carries an outboard bearing for a steering input control. This along with an inboard bearing can define a steering input axis.

A steering transmission between a steering input and output can be routed indirectly, such as through a series of articulated shafts and intervening couplings. Desirably, the couplings are with Hook type universal joints or a convoluted torque tube configured to give a constant angular acceleration or constant velocity effect.

For control purposes, a front wheel carrier fork turning axis can be regarded as a steering output axis. The Applicants envisage that the steering input and output axes can be relatively displaced or offset angularly, without undermining steering action or stability. An inappropriate steering input and so output action can induce tip over and lean. Similarly, or conversely, a frame lean or tip to one side can induce a turn tendency, albeit perversely to the opposite side. For cycle control a rider must contend with and arbitrate between both steering and tip or lean inputs having respectively an associated secondary tipping or turning effect. The respective centres of gravity of the cycle and rider contribute a turning moment when to the side of a ground contact point of the cycle, or indeed the rider. Inadvertent rider corrective, restorative or directive input of either kind, even when trying to straighten up or balance evenly, can induce an unexpected and unsettling effect, which a rider then has to counter appropriately and promptly, as beyond a certain point, the upset's are not restorable readily if at all time before the bicycle strikes the ground. At best a cycle of oscillations may be engendered which a rider has to dampen.

In a particular construction of the Applicants an upper bearing carrier for the steering output axis is carried inboard of an outboard extended frame end termination and is a transition point for departure of a steering input axis away from the steering output axis.

In contrast, in a conventional cycle configuration the steering input and output axes are largely wholly coincident or closely aligned. As with a conventional handlebar steering input control, an offset mounting stem can be fitted to offset the steering bar input control from the steering input axis and/or to incline the steering input plane about the steering input axis. Various steering input controls from bars, through yokes to wheels could be carried on the end of the reorientated steering input axis.

With an appropriately orientated steering input plane, such as one presented orthogonal to a riders arms and maintained as such throughout a steering arc, steering without forward lean allows a rider to look behind, to the side and around, without inadvertently imparting steering input through rider trunk, shoulder or arm movement.

This obviates a distraction of uncommanded turn and tip and so helps raise rider situational awareness while steering whilst preserving stability. The steering input axis can be far more inclined than the steering output axis and similarly the steering input plane can be more inclined to the horizontal than a conventional cycle.

A rider's head represents a significant proportion of overall rider mass and weight, so a lean-forward, head-forward riding, shoulder hunched stance can bring mass more over the front wheel and reduce residual rider trunk mass behind the wheel. Movement of the mass over and about the steering input axis in a head forward stance can be unsettling. Head movement to look around can unsettle the steering when the head is over or forward of the steering axis, whereas a head position well to the rear of the steering has less direct impact upon steering. Head movement thus represents a weight shift, albeit less pronounced for a more upright rider stance with head over the upper trunk, even when looking around, such as envisaged by the Applicants. The forward and rearward mass distribution in relation to the steering axis constitutes a polar moment of inertia about that axis, acting as two inter coupled opposed pendulum masses free to swing about a common axis.This mass distribution impacts upon the steering responsiveness of a cycle and the tendency to work with or against a turn.

Another factor is the effect of frame lean or tip to one side or other, that is lateral balance, upon front wheel turning; or conversely the effect of a turning input upon frame lean or tip.

Other considerations include so-called trail' geometry of relative disposition of steering axis, front wheel rotational axis and ground contact point, extended or extrapolated steering axis intersection with the ground. This along with a static or potential energy model of relative forward and rearward weight distribution, taking account both passive frame weight and active rider occupant weight. A perceived or actual tendency of a cycle to continue to lean or turn once a lean or turn has been initiated by a rider impacts upon stability and rider learning curve and ongoing confidence. Conversely, an predisposition, inclination or tendency to counter or lean out from a turn once initiated is disconcerting for a rider. A configuration compatible or consistent with a diversity of a frame formats and constructions would allow flexibility in adoption.

With a traditional cycle polygonal braced tubular element frame format, a drive pedal crank axis is located in a bearing set at a bottom bracket directly at the lower end of a slightly rearward inclined or canted seat stem support pillar consistent with a primarily downward leg and slightly forward driving action, braced by reaction against a seat or saddle mounted at the head of the seat tube. This is structurally sound to reflect an economic down thrust line of leg action between seat and pedal crank axis. The Applicants envisage a departure from this convention by adopting a crank axis well forward of a saddle stem position. A forward crank axis has also been adopted in the Giant Revive (Trade Mark) model, but with a more greatly inclined than conventional coincident raked steering input and output axis with a tiller steer extended reach handle bar.

Pedal down thrust is assisted or boosted on occasion, such as to address inclines, with the whole rider body weight by lifting clear of the saddle and standing upright to bring weight to bear successively upon the pedals.This in turn can be complemented by a cyclical repeated rocking or swinging the frame from side-to-side action between the riders legs to transfer the downward thrust between opposite pedals in turn. The nature of the drive dictates rider stance, in particular upper body lean forward with head brought down, with forward line of sight. This promotes a forward perception rather than looking to one side and behind for traffic and situational awareness.

Another frame type or style is a so-called recumbent or semi-recumbent, where a seat is set far back and a riders legs are placed somewhat forward and even also upward in a more horizontal, rather than vertical drive plane of traditional cycles. This allows a push-forward, rather than push-downward, drive action, to which a riders legs can readily adapt, braced against a seat or rather a seat back.

The low-slung ride height of recumbents offers drive efficiency and rider comfort, but is rather extreme for maintaining visibility especially for dense traffic in urban use and even the higher seating position of semi-recumbents is markedly lower that for a traditional saddle. Steering extended rearwardly to a low seated rider is common, also on occasion with hand drive crank arms on the steering. Stability is enhanced by a tricycle format, usually with twin rear wheels between which a rider sits.

Statement of Invention

The Applicants envisage using elements of what might be characterised as a semi-recumbent cycle format, but reconfigured with an elevated seat position, and rearward reach steering access from the seat, in a so-called command stance' -which is more suited for an urban or street use. Thus according to one aspect of the invention A cycle with a reach-backward or rearward reach steering input control from a steerable front wheel to a rearward (elevated) rider seat, the steering control input axis being inclined to or angularly offset from a steering output axis of a steerable wheel, for presentation close to outstretched seated rider forearms; with a pedal crank drive axis set (well) forward of the seat, for push forward pedal drive action by a seated rider.

A steering input axis could be brought close to or even at horizontal and so a steering input plane close to or at vertical. Such an orientation helps position the input control plane orthogonal or at right angles to a rider outstretched forearms and parallel to a shoulder line, so shoulder turn in looking to one side or behind has less tendency to make a rotational steering input. Merely canting backward or increasing the rake of a steering input axis, say with a single swivel joint, such as used in some recumbents and semi-recumbents, whilst achieving a departure of steering input from steering output axes, commonly with a steeply raked steering input axis, does not suffice to present a steering input plane orthogonal to a seated riders forearms. This without intrusion upon a riders legs as steering drive axis transposition can be routed upward, rearward and over them. Such an elevated rearward presentation of a steering input control close to a seat and supported by a corresponding articulated or upward and rearward cranked frame profile in a taller upright cycle format, rather than a known lower slung recumbent or semi-recumbent, is advantageous for urban use as a rider's head can remains up high and free to rotate through an arc about a more upright neck turning axis.

A transition or transposition of a steering axis input to output geometry is achieved with a series of couplings between, say, spaced shaffs carried in respective spaced bearings with a cranked upper forward frame whose profile follows that path change. Aside from a change in steering geometry there is a change in rider perception of steering response.

In one construction, as reflected in the annotations to Figure 3, a steerable front wheel carrier fork with steering output rotational axis is inclined at a rake angle theta to a ground plane and couples to an intermediate shaft and then to a steering input control shaft. An angle Betal between the fork or steering output axis and an intermediate shaff with a supplementary angular offset of Beta2 with a steering input axis. The combined angular transposition alpha between steering input and output axes allows a steering input control to reach back towards a control in close juxtaposition with a rear seat.

A pedal crank axis height P can be at or somewhat above a conventional cycle for easy transition of rider foot to the ground, but well forward of a seat squab for push forward pedal drive action. Reaction to a forward component of pedal thrust can be braced against by an adjustable seat back. Relieved of having to lean forward to steer, a rider stance can be characterised as more laid-back' or relaxed than for a conventional cycle. A rider is also free to look around, to either side or behind without weight shift or inadvertent steering input, so preserving directional stability and control.

A seat height Sh' above a ground plane can vary somewhat with rear suspension, such as a swing arm with a forward pivot at or close to the pedal crank axis. This in turn can induce some longitudinal weight shift and impact upon relative front and rear wheel loading. The seat longitudinal position can be close to a rear axle of nominal height H' above a ground plane with an attendant somewhat rear weight bias. A nominal wheelbase L' between respective front and rear wheel axes or wheel contact points can embrace a modest trail' or offset of the front fork line projection to the ground in relation the wheel axis. A nominal unladen c of g position is forward by a distance Sg of the rear wheel axis. A front wheel 17 radius RI and rear wheel 19 radius P2 can be adapted to frame size, rider and terrain. In this case a lower slung bottom frame profile with smaller wheels is shown..A front fork bearing B' set in a lower forward frame apex or transition serves as an upper or top bearing for a steering output axis. An upper frame beyond that is cranked rearward, in one or more stages or as a continuous sweep, enclosing a segmented steering column, or flexible drive such as of Figure 2k with a steering input axis carried in a top bearing at a frame upper rearward stub oxtonsion. This may bc adaptod to allow somo stocring input axis angular adjustment a', as shown in Figures 1 through 2b, 4 and 5.

A steering input control plane, that is a plane containing the movement arc(s) of the hand grips of steering input control used by the rider can be more inclined than conventional handlebars, and even upright or close to upright. The steering input axis is not constrained by the output axis of the steerable (front) wheel. This liberates' re-orientation and re-direction of the steering input axis and the disposition of the steering input control, along with the nature of that control itself. It also frees up adjustment of the steering output axis to meet certain handling conditions, without having to change the steering inpuT axis. Similarly, br an adjustable steering axis rake br a give steering output axis. this to counter a taller rider having to lean forward, even with a lower seat height.

This contrasts with a conventional handlebar set upon a mounting stem or top tube co-axial and indeed coincident with a steerable front wheel turning or steering execution' output axis. This, along with a near upright orientation, limits the rearward position of the handlebars. Absent extraordinary long-reach tiller' bars, with an awkward intrusive wide sweeping movement arc, this precludes a practical reach back toward the rider steering action. Even with these, the steering input or command arc is orthogonal to the common near vertical steering axis between steered wheel and handlebars, so the steering arc lies in a close to horizontal plane. The height of the steering input plane can be adjusted with a telescopic upper stem set in a frame clamp and profiled handlebars orientated to set handle grip disposition.

The steering input and coincident output axes of a conventional cycle are not completely upright or vertical, but typically set at a circa 71 through 75 (say a median 72) degrees, to the horizontal ground plane (or 18 degrees to a vertical of 90 degrees), depending upon cycle type adaptation for speed or terrain, such as a so-called mountain bike category.

Relieving some weight from a steerable front wheel may lighten the required steering input effort and improve perceived front wheel handling response, stability or control.

Similarly, disruptive feedback or kickback from interaction between the steerable front wheel and ground contact surface, reflecting the steering geometry, may be countered or dampened by steering weight or loading.

A simple steering input control such as a straight or cranked bar or yoke, with opposed hand grips at each end, may have a steering input plane containing those grips orthogonal to a steering input axis of rotation. More elaborate steering input controls may have opposed arms and handles set in a plane inclined to the steering input axis with an attendant more complex steering motion. This can be initially disconcerting, but familiarised with by use.The steering input control plane and the span and orientation of handle grips dictate the nature of steering inputs, which in turn require certain rider body and/or limb movement. Thus, say, a forearms close together close-coupled steering grip may be adopted with a crouched or hunched body with head down for a competition speed bike.

Conversely, rider body or limb movement dictated by other requirements, such as to look to one side or around, and/or the very act of pedal drive of the cycle with alternate sideways rocking motion, can impart inadvertent steering input and thus provoke a cycle directional change reaction. The simple act of a rider leaning on the steering input control, with attendant forward weight-shift, can engender an interaction between rider movement and steering and a reaction in cycle direction.

Front wheel turn and lean is inter-related with frame lean and follow-through turn of the front wheel. Sudden or excessive turn or lean can provoke instability and abrupt fall over to one side beyond a point of recovery by rider lateral weight shift. With a reach-back steering control operative in a somewhat more upright steering input control plane, rider steering inputs are less affected or wholly unaffected by the weight of a rider leaning forward on to the steering controls, nor by rider shift, twist or turn to look around. Even the weight of a rider hands and forearms resting at opposite on a steering control tend to counterbalance one another, so have net minimal and of no significant influence.

The turning or swivel axis of the steered (usually front) wheel(s), or the steering output axis depicted by a chained line in Figure 3, is generally rearwardly inclined to the vertical, generally optimised at circa nominal 28 degrees to the vertical (or 72 degrees to the horizontal) for a self-aligning castor angle, through a modest trail of the point of intersection of the steering axis and the ground behind the downward projection of the axle of the steered wheel.

The (inter)coupling or transmission between the steering (input) control and the steering output control, that is a mechanism or actuator moving the steered wheel need no longer be a close to upright straight shaft surmounted by transverse handlebars, but rather can be a transitional series of intermediate articulated shafts or columns or a continuous flexible drive shaft terminating in steering control such as a yoke or wheel. A final coupling, articulated or swivel joint close to the control could allow tilt adjustment of the steering plane relative to the penultimate steering drive (stub) shaft or column. A rider perceives the last or closest coupling as an immediate point about which steering is effected. This may result in an initially disconcerting detachment or disconnect' from the steering articulation of the front wheel, as the rider no longer looks down from directly over that wheel from a head above the handlebars stance and there is no one-to-one immediate visual connection between steering input and output angular movement about a shared steering axis.

An example long wheelbase (Long Rider) recumbent with reach back steering and articulated coupling to a steerable front wheel has a forward pedal crank drive axis and a low slung set with an extended backrest, but does not provide the command position or elevated driving stance sought by the Applicants. A 1936 Pathe News Reel clip shows a more upright stance with a steering wheel and articulated coupling to a front wheel.

Transition or transposition of a steering action, through progressively turned or re-orientated steering transmission, from a steerable wheel ground contact point, to a wheel carrier (fork) leg to frame upper and lower swivel mounting, through a series of transmission couplings and thence to a rearward steering input control, such as a steering yoke, is desirably a smooth continuum, with minimal friction and even acceleration in angular displacement. Uniform angular acceleration with angular displacement, over the majority if not the entirety of a steering control arc, is desirable for consistency of steering feel. Steering can be effected through steering control with backward reach towards the only slightly outstretched arms of a rider sat upright and even leaning slightly backwards against a rear seat rest. A rider can look sideways and behind without removing hands from the steering and with minimal shoulder and trunk twist.

Dispositions of seat, pedal drive (crank axis) and steering represent key anchor' points in cycle geometry. Their relative dispositions, at corner apices of a triangle of certain proportions, are critical to suit a rider Thus steering must be within easy reach of a rider's hands and pedals within easy reach of a riders feet. For reassurance, a seated rider must also be able to put at least one foot down to reach the ground when stationary, with at most only modest frame tilt to one side. These are inter-related considerations. So, with an otherwise fixed frame format, provision for adjustment to individual riders is important. In practice, it is easier to adjust the seat and/or handlebar position on the steering input axis (albeit not necessarily the angle or orientation of that axis), than that of the drive crank axis, which is commonly captive to a frame bottom bracket apex. Seat-to-pedal reach reflects leg throw' between hip swivel, knee bend and outstretch in reciprocating rotary pedal drive action. A cycle frame format which lends itself to generous leg and/or arm adjustability contributes to matching' a cycle to a rider for a more efficient, stable and safer ride experience. Provision of fore and aft seat travel, along with height adjustment and a height and recline adjustable back rest, complement a steering reach and rake adjustment to optimise rider comfort.

A backrest, at least for a lower back, is a supportive adjunct to the seat to brace against pedal drive reaction. With a higher pedal crank axis the drive reaction becomes more fore and aft or horizontal and not directly countered by rider weight downward upon the seat, so requiring at least a rear seat lip, if not a backrest, which in itself admits of adjustment relative to the seat. A mapped or profiled seat adjustment path can be described by a track and/or mounting frame profile. An inclined seat mounting track and/or frame can serve for both fore and aft or longitudinal adjustment and vertical height adjustment. An independent mounting track for a backrest can also provide relative movement of seat and backrest. The proportions of each adjustment depend on the local profile of the track. A sloping linear profile from the region of a lower forward pedal crank axis up to a rearward seating position above and over a rear wheel can be provided by a linear track or a track of non-linear or curvilinear form. Continuous or segmented tracks can be adopted. The Applicants envisage a frame profile with a pronounced rear upward slope and even an end upturn to facilitate this.

In embodiments of the invention, provision for an inclined or closer to upright steering plane is provided along with a forward and upward pedal drive position from a rearward seating position, whose position admits of considerable adjustment range both in height and longitudinally. This to emulate some aspects of a so-called semi-recumbent or push-forward pedal drive style or stance, yet with a high seating position more akin to that of a conventional cycle. This without disconcerting a rider as a leg can readily still be placed on the ground from the pedals. Front wheel steering output axis or castor angle can be consistent with that of established convention, whilst the steering transmission can bring the steering drive rearward to the seat position, to be within easy arms reach of a seated rider without the rider's trunk having to lean forward or outstretch arms unduly. The distance between pedals and the ground determines the time taken to transfer a rider's feet from the pedals to the ground, such as when coming to a halt, or conversely from the ground to the pedals when starting off. The pedal crank throw and concomitant range or reach of leg outstretch thrust drive leverage action can reflect this.

A hollow monocoque frame construction can be adopted for stiffness and rigidity even with an open frame format. A diamond-shaped faceted face frame section suits this and ease of fabrication while providing ample internal storage space for such options as electric drive. A battery pack could be fitted to or within a rear frame upturn behind a seat and backrest. Battery profiles can be moulded to suit mounting or storage space.

Figure 15 shows an open throat or yoke frame of faceted profile and trapezoidal or diamond cross-section varied over the frame span, consistent with a stiff and optionally hollow monocoque structure..

A seat back-rest is appropriate, when a rider no longer leans forward upon the handlebars, but rather can lean back for lower spine support. Adjustment of pedal crank axis position is complex to achieve, given the need to preserve an active drive train, but leg reach from seat to pedals can be adjusted by a generous range of seat for and aft and up and down travel, conveniently along a rearward inclined saddle stem.

Wheelbase adjustability could be useful but is unusual. Folding frame derivative variants are feasible, but complex.

The Revive' (Trade Mark) bike from Giant Bicycles is a an example of a high seat, semi-recumbent bike with a steering rearward reach on a pivot arm, albeit with a more inclined than conventional front wheel fork steering axis. The seat on that bike is high and upright, but with a range of adjustment in height and travel by adopting a diagonal seat pillar. Another feature is a swing arm rear suspension.

The way in which a user interacts with the steering in order to steer, either to stay straight-ahead or change direction, has an important contribution to safety, not least to allow rearward over-the shoulder glances, without tendency to move the steering and unsettle the bike. If a user inadvertently initiates or encounters wobble' when trying to look behind, there is a disincentive to do so, with road safety consequences.

Steering involves an output interaction between the cycle steered wheel and the ground, an input interaction with a rider, with an intervening steering coupling or transmission mechanism. A common front wheel steering mounting is through a pair of front forks with a swivel stem mounted in spaced carrier bearings in a frame front tube.

The mounting geometry of the steered road wheel can embody a certain steering axis or castor angle geometry for an individual wheel in a vertical plane, along with the geometry of the steering input, such as a yoke or wheel, presented to the rider.

A steering input control which reaches back to the rider, allows the rider to lean back against a back rest while continuing to steer and to look sideways and/or rearward without inadvertent interaction with the steering. The user does not lean down upon or rest any weight upon the steering, whether for support or physiological comfort or respite. Rather the action is much more akin to a driver in a motor vehicle. So a rider can be much more relaxed in steering, with only minimal effort, finger tip control. A upright with inclined rearward extended steering column and high set steering wheel is also known, but the rider is perched up high in a seat and the overall hight c of g more challenging to balance and prone to tip over sideways.

It is also desirable to retain an optimum inclination or castor angle for the front wheel (fork) pivot, or steering output, axis, whilst transferring the steering coupling rearward to the rider. In recumbent cycle variants extreme rearward steering reach of extended handlebars, steering wheels or tillers has been adopted, along with a hands down and to the side hand grips with a lower remote steering transfer linkage. Side arm steering is also known in tricycles with arms to both sides. Some full (that is very low slung) recumbents designs adopt an extreme back recline and feet outstretched forward and upward stance with pedals above the front wheels, with a long drive train back to the rear wheels. Thai said, tall high-seat recumbents or so-called high racers are also known, such as the Challenge Seiran 26' (TM). Front wheel drive with turning handle arms directly connected to the front wheels is known. An example is hand cycles with a hand crank at the head of a front wheel fork stem, in a tricycle frame format, with twin rear wheels. Disability or wheel chair versions with add-on drive and steer front wheel adaptations of this have also been devised for the disabled and physically challenged under the Team Hybrid brand.

Bringing a steering input control back towards the rider to save rider lean forward may not sufficient in itself, unless the steering input axis and steering input plane, traversed by a steering input control arm' is correctly orientated. The Applicants envisage a steering yoke control format, such as with upturned handle grips at opposite ends of a straight or cranked bar coupled to the end of a steering column rearwardly inclined from a more conventional upright. A rearward extended tiller might substitute, provided the steering movement arc is not excessive, that is minimal sideways arm swing would be required to change direction. A tiller is also liable to reflect inadvertent rider body or limb movement.

One implementation would be an articulated steering column, in one or more elongate linear shaft sections, with intervening swivel joint coupling, and/or a flexible drive shaft between a steering head at the front wheel fork swivel and the rider hand position. A proprietary flexible rotary drive shaft coupling might be employed, such as for a power drill to a bit chuck. A simple hook joint might suffice for a directional change of a rotary shaft, or constant velocity joint or effective joint combination might also be contemplated, albeit at greater complexity and expense. A steering yoke might be substituted by a steering wheel or a blend or combination of both. Aircraft yoke or boat tiller parallels might be used.

Elevating or raising a low-profile, ground hugging, recumbent or semi-recumbent style for street use is in a sense a contra to convention change envisaged with the present invention, but certain recumbent features of rearward steering reach and legs forward drive ethos have relevance for a street bike, provided lateral balance can be preserved.

Thus, for example, a feet-to-floor (when sat upon the seat) geometry would give rider reassurance. A front wheel steer with rear wheel drive combination can be adopted, but with electric drive hub options a steerable front wheel drive can be contrived without undue complexity except provision to feed power to the drive hub, such as by cables routed through hollow front fork and frame elements. Wheel size, relative front and rear wheel size and wheelbase admit of considerable variation. Similarly, for bicycle, tricycle and quadricycle configurations. A rear seat disposition is generally above and/or forward of a rear wheel rim or wheel axle.

A steering input plane orthogonal to a steering input axis, itself independent of a steering output axis, is orientated more upright than in a conventional cycle handlebars, but still generally orthogonal to a rider forearms, as these are more horizontal than upright, absent a component of downward lean. The steering input orientation, steering output geometry and the relationship between the no longer coincident or mutually aligned input and output axes have a bearing upon rider perception of handling rid ability and stability.

A rider (upper body) weight leaning or bearing upon handlebars in a conventional cycle configuration can help load', stabilise and dampen steering input, response and reaction. There is less tendency for a rider's arms to flail about or wobble when applying control input to what is otherwise a very lightly loaded steerable front wheel.

Similarly in countering shocks and feedback displacement due to road surface imperfections. A rider is thus part of the steering control coupling'. If the steering input plane is canted somewhat away from strictly orthogonal to an input axis, such as upward away from a riders legs a somewhat less than uniform wobbly steering action can arise as the input control rotates about the input axis. This can be less apparent with a yoke of opposed arms with respective hand grips, than say a continuous circular wheel. The steering input axis can be angled considerably away from the steering output axis. Thus for example a some 60 degree relative angular spread splay, misalignment or offset might be adopted. Conveniently, this is distributed over two or more transitions.

The steerable front wheel mounting geometry impacts upon any self-centring action or tendency. Equilibrium also reflects the relationship between frame lean or tip and front wheel turning. A canted wheel mounting axis can engender a castor action of wheel turn ahead of frame lean.Excess stability is undesirable as it resists change so steerable wheel mounting close to instability can promote responsiveness with low control input forces.A lead or lag in front wheel rotational axis in relation to a steering mounting or output axis has a bearing upon stability as does any cant of wheel mounting forks with respect to that steering axis.The plane of frame lean is not coincident with the plane of the steerable front wheel except with both frame and wheel upright and wheel orientated straight ahead. This at best a temporary or transient mode for a cycle in motion when being driven by a mounted rider, rather than simply pushed along unladen. Perturbations from ground contact of the front wheel may trigger wheel turn or tip, and which are in turn reflected in overall cycle tip or lean possibly with a frame turn following or running counter to that of the front wheel.

Steering aside, other considerations include propulsion and weight distribution. A pedal drive crank axis set well forward of a seat position can be adopted for rider leg forward push or thrust without reliance upon downward weight. The crank axis height above the ground should allow ready transition between pedals and the ground, consistent with a seat height in relation to overall leg length for pedal reach and driving action.

Another factor of frame configuration and geometry is the c of g when unladed and ridden. With a steerable front wheel mounting axis or castor angle rearwardly inclined to the vertical, there is a tendency for a front wheel to fall' or flop' inward, into or toward a frame lean. Conversely, there is a tendency for frame lean in opposition away or outward upon front wheel steer inward. The c of g transition of a tilted cycle frame is such as to minimise the associated gravitational potential energy with an attendant c of g lowering torque effect.

The ground contact point of front wheel is or need be not intersected by steering axis A steerable front wheel runs naturally in the line of its own plane, along its own so-called tractrix or pursuit curve; the trailing frame and rear wheel will swing into line behind. To an observer on the cycle it may appear that self-centring is occurring, though it is the rest of the bike and not the front wheel that is swinging. The steering input control itself has a moment of inertia about the steering input axis. This impacts upon steering load, responsiveness, self-corrective or self-righting action and concomitant difficulty to ride Whilst a frame might be regard as passive, in use its inherent static and dynamic characteristics have a bearing upon ridability. Moreover, a rider is not inert, but rather a responsive contributor in an overall behavioural equation.

To assist exploration of geometry and ergonomics the Applicants have devised a static test rig or support stand, built in timber for ease and economy. Refinement of this rig was progressed to a dynamic mule, initially using a donor bike, with a cannibalised frame, to preface a bespoke frame. An example rig comprises a shallow depth box with a pair of spaced upright panels with intervening spacer blocks and beams representing a steering column and saddle seat support stem. Cross-holes drilled between the panels can accommodate pedal crank axle and wheel axles where wheels are fitted to give a ride height. Opposite side braces with transverse floor beams may also be fitted to keep the panel assembly upright. In the latter case, limited rolling along a confined linear track might be admitted.

One empirical experimental approach was to vary the pedal crank axis position in relation to the seat, whose height and longitudinal position may also be changed. The steering position was adjusted in height and reach to a rider sat on a given seat position. Frame height or tilt was adjusted by setting the panels on support legs with peg and slot fittings. Wheelbase could be disregard or adjusted by expanding the panel longitudinal span with an adjustable spacing split end panel on stand format. Broad ergonomic considerations dictated overall rig size and proportions upon which personalised adjustments can be made. The rig may also be used to explore steering transmission coupling from a forward position at the steerable front wheel to a rearward position towards the user, using universal swivel or hook joints and flexible shafts. A front hinged assembly might also be contrived for subdividing the front panel assembly further with a forward hinged portion to simulate a turning front wheel mounting. The hinge pivot axis would be inclined to the vertical, so as to achieve a ground contact point for the wheel ahead of a notional point of intersection of the pivot axis with the ground, with an included angle representing a desired castor angle.

Aspects of the invention variously provide: 1.

A cycle with a rearward seating, pedal crank axis forward disposition, and rearward or reach-back' (from a front or forward) steering coupling, to present to a rear seated rider a steering input control arm, such as a yoke with handles, arms or a wheel. This could be operable in a steering control input plane generally orthogonal to a steering column or shaft and inclined, up to as much as near orthogonal, to a ground plane, to allow steering in an inclined up to a near upright or vertical plane by riders arms and wrists outstretched and near horizontal. 2.

A cycle with a flexible or fragmented directional change steering column from a front wheel carrier fork to a rearward steering arm, yoke or wheel presented close to the outstretched arms of a rearward seated rider. 3.

An forward' pedal crank axis disposition, well forward of a seat, to allow an extended-leg, push-forward driving action, while seated somewhat higher and rearward. Pedal crank axis could be at or somewhat above a conventional height so not too far from the ground.

For an urban or street bike' configuration, the seat can be at a conventional' height or somewhat higher and optionally somewhat further back. A back rest can also usefully be fitted and used, as a seated rider can still pedal while leaning back against the back rest. Thus, unlike a conventional bike, a rider does not lean forward or upon the steering arm. There is no tendency or encouragement to do so, which may be initially disconcerting to a rider, but to which a rider can rapidly become accustomed or acclimatised. While leaning back and supported by a back rest, a seated rider can also comfortably look to one side and backwards over the shoulder, while continuing to steer, either single or double-handed, with directional consistency and stability, so preserving a stable riding position, without erratic unpredictable, uncommanded sideways wobble. This allows safer forward progress in an intended direction and greater overall traffic awareness before and during turning manoeuvre. A rider is more encouraged and reassured to look around, without fear of instability. So rider confidence is built. The steering input control is no longer an essentially element to rider stance and balance as with a conventional lean-forward' cycle format.

As no rider weight is, or need be, applied by leaning over to rest hands, arms and upper trunk, upon the steering, a minimal turning effort is required, with only fingertip or thumb rest control necessary. Once recognised and taken into account with steering input forces and turning angle, his disconnect' in turn engenders a more precise, careful, controlled steering action, with greater directional refinement and consistency.

The riding stance is more relaxed, yet propulsive effort and leverage promoted. This is advantageous in uphill climb performance. Ride stability is improved if no undue effort is expended, with attendant reduced cyclical or periodic unevenness or jerking in pedal drive action. Mechanical advantage or disadvantage in steering ratio can be adjusted through a steering transfer or coupling box in the steering drive chain. A modicum of resistance or loading can be imported in the drive chain to give a certain feel', feedback or reactive response and so rider certainty' or reassurance.

A lower or modest saddle height, such as by reduced seat pillar length or frame depth, allows a rider to rest both feet on the ground, with legs astride the frame. This gives a rider some fall-back' or reserve confidence that any lateral imbalance or tip-over risk can quickly and readily be suppressed, countered or corrected, whether straight-ahead or in a turn. A somewhat longer drive chain is required for a pedal crank forward position with a standard rear wheel position or an even longer wheel base. This allows some slack and shock cushion provision. A floating carrier idler cog in or alongside tensioner transfer gear sprocket train can be used to pick up and gather chain slack.

In a full recumbent a lower seat position is adopted, but this can be intimidating in traffic, with poor visibility of the road ahead and overwhelmed by higher vehicles to one side. Similarly, the low profile makes the bike less visible to others. A somewhat higher seat position of a semi-recumbent helps address this, but the Applicants envisage a close to conventional, normal, or even higher than normal, seat position for greater prominence, but consistent with leg reach to the ground. This is more readily achievable with a steering which reaches rearward or backward and upward away from the steering output axis from the front to a rider, without a rider having to lean forward, to a largely fixed forward steering, such as handlebars; so a rider can rather lean back for support by a seat back rest while continuing to steer. The rearward steering reach and inclination of the steering input axis, and the consequent more upright inclination of the steering input control plane, can be adjusted for a wide range of seat adjustment, either or both longitudinal or in height, say combined as a diagonal sloping ramp. A telescopic steering column, with a forward rotary pivot, such as through a universal coupling joint, and rearward adjustable height support would enable this. A rearward joint might also be fitted to allow another directional transition closer to the rider.

A wider, longer, more deeper upholstered saddle seat, at least toward the rear under rider buttocks adjacent a backrest, with an upturned lip lead into a backrest can be used with a less leg downward or more leg forward and upward pedal driving stance, so a saddle nose is less intrusive between a rider's thighs or sublimated into the body of the seat squab, allowing rider thighs to be supported more forward, with forelegs hanging downward over the seat front edge. Such a more substantial seat is more akin to a motorcycle seat, than a conventional cycle saddle. Seat squab and backrest could be integrated stylistically yet allow independent adjustment of height and tilt, compatible with either male or female riders. Seat arm supports could be fitted, say cantilevered forward from the back rest, to allow a fingertip, crooked thumb, wrist and forearm steering action with minimal upper arm, shoulder or upper trunk movement. This is more akin to vehicle steering than conventional cycle steering through forward set handlebars.

There remains scope for more elaborate rear wheel mounting, such as articulated suspension arms, with a forward pivot rearward longitudinal swing arm to allow a long wheel travel with a low spring rate and thus a softer more comfortable ride to complement a softer seat cushion, which might be supplemented by a sprung suspended seat. A soft ride promotes a relaxed rider steering command, without road surface bumps displacing a rider's body or limbs, to induce an unintended jerky steering action. Suspension action should not impart any unintended or untoward disconcerting steering input or directional change. Rear suspension action need to be transmitted to or compromise front steering. Generally vertical upward and downward rear wheel travel does not couple to or give disconcerting uncommanded front wheel input. A front wheel suspension and/or an articulated sprung frame may also be used for an even softer ride, capable of poor uneven road surface or rough terrain riding. Again, if a rider is less jolted around, inadvertent uncontrolled abrupt steering input jerks are less likely.

Reliance is not placed upon the steering for balance, for consistent directionally-stable progress. That is, with less or no lateral wobble' ,steering action in itself does not tend to de-stabilise or unbalance, but rather serves as a prop', as with driving a vehicle.

Fitting a remote steering wheel with inclined steering column to substitute for handlebars on a conventional cycle does not achieve the benefits of the invention as arm turing and feeding the wheel through the hands is required. This is not conducive to looking sideways, let alone rearward. Similarly, a circa 1936 cycle (per Pathe News web archive) with a high-set steering wheel adopted a prominent elevated raked steering column to a steering box over a front wheel, in a rather bulky, obtrusive and unwieldy configuration, which again requires substantive rider arm movement. The tall somewhat ungainly configuration also did not lend itself to lateral stability; nor a rider looking over the shoulder sideways or rearwards without turning the upper body trunk.

In contrast, a compact, stowable, collapse-fold frame format is compatible with rearward steering reach of the invention, such as by locating steering coupling joints at frame fold and steering drive articulation points.

The Applicants envisage the option of an unobtrusive remote steering coupling drive for a rearward-reaching' steering yoke, wheel, arms, handles or the like for a steerable forward or front wheel. In more sophisticated systems, a fly-by-wire' remote control module with side stick control might be adopted. A power actuator module, run from a lightweight on-board battery, and operable on the front forks and reacting between frame and forks, could be controlled by a lightweight steering director near the rider, with, say, an intervening electrical cable or wireless link. A side-stick control handle format might be employed to either or both sides. That aside, the format lends itself to an electric powered or electric assist variant with say an electric motor integrated into a drive hub and a rechargeable battery pack slung externally of a frame or internally within a large section hollow monocoque frame section.

Embodiments There now follows a description or some particular embodiments of the invention by way of example only with reference to the accompanying diagrammatic and schematic drawings in which: Figures I through 5 are minimalist diagrams of cycle layouts and geometry; with Figures 1 and 2 omifting frame detail; Figures 3 through S with variant frame detail.

Figures 6 and 7 introduce an abstract rider mannequin to the elements of Figures 1 and 2. Figures 8 and 9 use a mannequin to convey a facility to look to one side and behind while seated and still holding a rearward reach steering input control yoke. Figures 10 through 12 express particular open frame designs with features of Figures 1 through 9.

Figures 13 and 14 express closed lattice frame alternatives to Figures 10 through 12.

More specifically, Figure 1 shows a side elevation of the relative disposition and geometry of principal cycle elements, of steering input axis* with input control yoke 12, pedal crank axis 15, seat squab 11 and back rest 13.

An (optionally adjustable) inclined steering input axis is at an angular offset from an independent steering output axis of a steerable front wheel.

A reach backward steering input control allows rider steer from a rearward upward seat disposition, without having to lean or reach unduly torward. or to lean upon a steering input control. A rotational steering control throughout, rather than an extended cranked-back tiller steering arm (known from Ligfietsent of Ligfietswinkel.nl) or single jointed steering column (such as of Sigma Recumbent Cruzbike) is adopted.

A range of wheel size or diameter can be accommodated, reflected by multiple mutually offset wheel circumferential arcs Dl, D2, D3 etc. Seat vertical and longitudinal adjustment and similarly that of a seat back rest is reflected as a combination adjustability in an inclined rearwardly upward sloping (at an indicative angle B) mounting ramp again merely as an example. Steering input control and in particular a steering input control plane is adjustable over a certain angular range, and optional also for longitudinal reach. Intervening frame infill between front and rear wheels is omitted for clarity, but examples are given in Figures 3 through 5 and developed designs in Figures 10 through 14. The steering input plane is presented close up to a rear seated rider in an inclined manner akin to a vehicle steering, so is not relied upon for rider support as with a conventional handlebar, but can be operated by forearm and upper arm movement in relation to that plane; the mannequin depictions of Figures 6 and 7 show a rider forearms generally orthogonal to the steering input plane;.This is carried through to Figures 8 and 9 depicting a rider turning to look to one side and behind, but without tendency for inadvertent steering input. Rather the head, neck and upper trunk rotation or twist are accommodate naturally and instinctively by extension or retraction of opposite arms; Figures 2A and 2B shows a development of Figure I with alternative steering transmission couplings; a consideration is to achieve a constant velocity rate of angular transmission in the transmission over a range of angular rotation; More specifically, Figure 2A shows an intermediate continuous flexible drive section 22 conjoined with a coupling to a steering output axis 22 down to a steerable front wheel 17 axis 27 of rake angle theta to the vertical; steering input axis is adjustable over a range arc alpha; Figure 2B shows articulated linear elongate shafts or columns with intervening joints; the joints can individually be Hooke-type at each junction with a cumulative constant velocity or near equivalent effect; In practice, a combination of flexible and articulated drive sections could be employed, to reach clear over a riders legs; Figures 3 through 5 shows variant open' frame formats for the configurations of of Figures I and 2, again with scope for a range of wheel diameters for front (steerable) and rear (driven) wheels. Front (hand crank) drives and articulated rear wheel steering have been devised for cycles, but and might be adopted for some variants, but are not explored here. The steering starts from the front but ends toward the rear. It is desirably more that simply extended or long reach handlebars with a long lever arm tiller action such as have been adopted before, but rather a steering input control more akin to a wheel or yoke, but whose pivot axis is also brought rearward closer to a rear seat position. Provision can be made for adjusting the longitudinal extent of rearward reach and also the inclination of the steering input plane; this to suit a rearward seated rider with arms forward without undue stretch and without lean forward and consequent head down rider stance. The steering facility is brought back to suit a seated upright rider, rather then a rider having to bend or stoop as with a conventional cycle with handlebars. A drive pedal crank axis is set around mid-span of the frame or wheelbase and as such well forward of the seat, unconstrained by any seat stem pillar and opposite bottom crank mounting of a conventional cycle frame. A generally upright but inclined to the vertical steering output axis is adopted for an effective castor angle and attendant trail following action. This engenders a neutral steering behaviour with a cycle following but not tending inside or outside of a steering setting or indeed to resist turns prompted or dictated by lean angle changes turning at all. Consistent predictable behaviour at different running speed is desirable. The head tube and headstock bearings of a conventional cycle are replaced by a lower set fork carrier bearing set.

More specifically, Figures 3A and 3B shows a segmented rectilinear angular or polygonal hollow moulded monocoque frame format, with a rear seat ramp mounting to allow fore-and-aft and independent tilt recline seat and/or seat back adjustment; a forward mounting steering is brought back towards the rear seat position, to allow a seated rider to reach the steering without having to lean forward as with a conventional cycle; so a more upper trunk and head upright rider stance is engendered with benefit for drive view and awareness of surroundings, in particular to either one side and/or behind; Figure 3A shows a manual powered cycle wth reach back upward steering with trailing arm rear suspension; Figure 3B shows an electric powered or electric assist variant of Figure 13A, with battery pack and electronic control module incorporated with a hollow frame; Figure 4 shows a continuous curvilinear arcuate swoop frame format; with a swept backward and upward tail element which can serve as an inclined ramp for rear seat mounting; this to allow seat adjustability to suit a rider leg reach to an (in this case fixed) forward pedal position; a rear wheel is depicted on a conventional fixed triangulated rear frame, but a swing arm frame reacting with a suspension strut would be an alternative; Figure 5 shows a combination frame with rectilinear and curved frame portions with elements of Figures 3 and 4 formats; a final steering column section starts from the head of a front steerable wheel carrier and extends rearwards and upwards to reflect the disposition of the rear frame; thus steering reach can follow seat adjustment. This might suit an extruded or folded stiffened sheet construction such has been adopted in the past for motor scooters.

Figures 6 and 7 show a cycle configuration without frame inf ill with the features of Figures I, 3, 4 and 5, respectively with a abstract mannequin representation of a rider seated respectively in pedal drive and stationary foot-on-ground/floor positions; More specifically, Figure 6 shows a seated rider mannequin with feet on pedals and arms and hands outstretched to grasp a rearwardly presented steering input control, in this case a steering yoke, without a rider upper body having to lean forward, so preserving an upright stance with feet well forward of a rearward seating position; the amount of arm outstretch can be adjusted to suit rider comfort when seated upright and leaning back upon a backrest; the rider arms are not required to carry or transfer any rider weight forward as with a conventional cycle; the forearms are generally orthogonal to a steering input plane containing a control yoke with opposed handle grips; Figure 7 shows the seated rider of Figure 6 with one foot on the ground and the other on a pedal; the seat hight might also allow both feet on the ground, so the riders legs straddle an lower intervening cycle frame; The effect or consequence of the upright rider stance with steering brought back towards the seated rider, in allowing greater rider situational awareness and looking to one side and the rear, without having to take hands of the steering, so preserving stability and control, is conveyed in Figures 8 and 9; Figures 8 and 9 show the seated mannequin of Figure 6 orientated to show a seated rider looking to one side and behind, with rotation, swivel or twist of head, neck, upper body trunk or torso and waist; More specifically, Figure 8 shows a 3-D view from one side; a seated rider is depicted with upright seated stance and modest upper body twist and head turn about the neck, looking to one side and right around to the rear, while keeping both hands-on the rearward disposed steering input control, in this case a yoke,, kept in a straight-ahead position; Figure 9 shows a 3-D view from above of Figure 8 to convey more clearly the extreme range of vision and thus improved situational awareness, with hands-on steering; the rider can continue to keep both feet on the pedals and preserve balance; The rationale is that a seated rider is more likely to look to the side and behind if that can be done retaining steering control without unsettling lateral stability.

Figure 10, 11 and 12 show example open-frame design developments of the formats of Figures 1 through 9; these lend themselves to an integrated unitary monocoque moulded body construction; so they feature some commonality of core elements but with respective development of form; More specifically, Figure 10 shows an open frame of flattened' upper profile, curvilinear ribbon strip configuration, with swing arm rear wheel suspension; a spring and damper strut reacts between a carrier arm and the rear frame; a continuous upward and rearward swept upper frame houses a steering transmission and presents an open steering input control yoke to the rear seat position; some fore-and-aft adjustment of steering can be accommodated by a telescopic internal coupling concealed with the frame upper outboard end; Figure 11 shows an open angular frame with pronounced rear upward limb for seat mounting; a pronounced upward rear frame limb or blade arm supports a range of seat travel adjustability and allows a triangular side profile or tapered wedge pannier (not shown) to be fitted underneath above the rear wheel; a diamond multi-facet frame section imparts stiffness to counter bending of the otherwise vulnerable open frame format; bracing of critical stressed regions such as steerable front wheel mounting, upswept steering arm, lower drive crank mounting are reinforced by pronounced deep hollow local frame sections; these provide general purpose luggage or bespoke ancillary storage, such as batteries, control electronics and motor drives for electric cycle variants; Figure 12 shows an open frame of curvilinear form with rear wheel wrap overlay; the seat adjustability profile follows the curvilinear frame end and tail; as with Figures 10 and 11 frame corner transitions are expressed in progressive curves for stress distribution; Figure 13 shows a closed format curvilinear lattice frame of intersecting networked grid elements for greater overall stiffness and rigidity; Figures 14A through 14P show a compilation of variant yoke frame and integrated wheel formats, with elements of Figures I through 13. Frame profile can integrate in function and visual style reach back steering, forward pedal crank axis and rear seat with backrest.

Figure 15 shows a cut-open or translucent frame 12 body with local cross-sections; The diverse cycle forms lend themselves to motorised or motor assist drives, consistent with an ethos of relaxed or laid back' cycling, as reflected in Figure 13B.

Inherent bracing of an open frame format, such as of Figures 2 through 12, can be achieved though the frame cross-sectional shape and size; even with a hollow section reliant upon the wall thickness; this can be supplemented by generous broad progressive sweeping angular transitions; the internal section can be used for storage, such as to accommodate power modules in an electric powered or power assist cycle variant.

Whilst the subject cycle, with reach-back steering and pedal-forward stance, lends itself to an open-frame format, such as a rectilinear V', curved U' or some combination thereof, other formats, such as closed or part-closed lattice forms can be used, with frame elements such as horizontal or diagonal cross-bars, spanning between front and rear frames contributing stiffness and rigidity; if overall wheelbase, footprint or size are not critical larger diameter front and/or rear wheels can be adopted for improved ride and/or handling; similar considerations apply to wheel mounting, wheel suspension, and steering geometry.

The frame could be fabricated by conventional means, from mutually inter coupled linear segments, such as welded end joint or sleeve stub tubing, bracing; or by more bespoke integrated or unitary moulding, more suited to curvilinear profiles and forms.

Referring to the drawings, principal elements of a basic, or common core', cycle 10 configuration comprise a seat II, a steering input control (such as yoke or wheel) 12, a seat backrest 13, a pedal crank 14, a pedal crank axis 15, with a steerable front wheel 17 with an axis 27 of diameter Df, a fixed rear wheel 19 with an axis 29 of diameter Dr, and a frame 18. A backrest 13 suits a laid back' rider stance, with a rider able to lean back supported with feet well forward of the seat, with a pedal push forward drive action braced by rider's trunk against the seat body, in particular a back rest. A backrest 13 is useful for an upright seated rider stance, in turn achievable as the rider does not have to lean forward to rest upon front handlebars, as the steering input control yoke is brought back toward the rider and is within ready grasp, without forward lean or stretch or undue arm outstretch. Seat fore and aft or rather diagonal ramp adjustment can be used to better accommodate different rider sizes with a chosen degree of arm outward stretch or articulation.

Figures I through 5 are intended to convey underlying geometry, without restriction to any particular design, allowing a range of front and wheel diameters, whether the same or different, as depicted by an indicative range of diameters Dl, D2 and D3 about variable wheel centre positions reflected in double-headed cross-arrows. Certain other Figures adopt a small wheel for a compact overall configuration, in particular wheelbase or overall longitudinal footprint or length; although the invention is applicable to large wheels or combinations or large and smaller wheels. Aside from ergonomic considerations of rider accommodation, wheel size and wheel base impact upon cycle handling and stability. Afusion of Figures 3, 10, 11 and 12 reflects a mature frame design used for a prototype.

Core geometry and configuration features, such as steering output axis rake angle, rake offset, trail, crank axis height, crank axis span to steerable front wheel axis, front and rear wheel radii and wheel axis heights, seat height, fork length, fork end offset, chain stay or drive crank to driven axle span, crank axis span to steerable front wheel axis, overall wheelbase, steering input control mounting stem length, rider weight disposition, distance between riders hands and steering input control axis, have a bearing upon hands-off and hands-on handling, stability and c of g. With a cycle of the present invention the steering head angle of a conventional cycle is transposed to an independent steering input control mounting angle. This affects the road reaction shock transmitted to rider as there is no longer a direct line between a riders hands and steering output axis or ground contact point, but rather an indirect offset path through independent steering input and output axes.

Figure 1 depicts elements of layout geometry, with a steering axis alpha reaching rearward toward a seat, but allowing a range of tilt adjustment alpha. A range of steering input control planes is shown. These can be transposed with longitudinal steering reach adjustment. Independent seat and back rest adjustment is indicated by opposite headed cross-arrows. Similarly, in principle for pedal crank axis adjustability, although in practice this is more complex and costly to implement and is more readily sacrificed for or substituted by seat adjustability.

A frame format supporting those principal elements admits of considerable variation, including either open, allowing rider leg step through, or closed, requiring rider leg step or swing over. The relative disposition of elements admits of adjustment, achievable by adjustment of individual elements longitudinally fore and aft and/or vertically. A front wheel pivots about steering output axis Sa, set at rearwardly inclined trail or castor angle theta and with an end turn-out to achieve a displacement or offset between wheel contact point and a notional intersection of extended wheel steering axis with the ground. In principle more upright or inclined steering output axis might be adopted, subject to trial.

The front and rear wheel axles and their respective rotational axes 27/Fa, 29/Ra may be fixed or carried movably by respective suspensions. Thus a front wheel 17 can be carried upon a telescopic leg or between forks or an articulated strut carrier arm.

Similarly, a rear 19 wheel can be carried upon a swing arm or articulated link or strut.

Articulated split frames with mutual hinge and intervening spring strut damper might also be used.

A rear wheel l9iWr is carried upon or between opposed frame tubes. A rear wheel drive Dr, such as a sprocket and chain, transfers pedal crank 15/Pc rotation to the rear wheel Wr, with the option of adjustable ratio gearing. A shaft drive transmission with end gearboxes might be adopted, as might hydraulic, electric or combination drive or converters.

A (non-driven -except in say electric drive hub variants) steerable front wheel Wf is carried upon a depending frame strut or stem, such as between paired forks or down-tubes, and pivots about a steering output axis So. The steering input control 12/Sc rotates about a steering input axis Si. A steering coupling or transmission 21/St bridges and intervenes between steering control and steered wheel and transfers steering control input to steering or steered wheel output so and can take diverse forms, such as successive articulated drive shaft segments 21 mutually entrained in series with intervening joints or a continuous flexible drive coupling 22.

A steering control input axis Sic and an orthogonal steering control input plane Sip are independent of a steering output axis So. The rake or angle of inclination Ri of the steering input axis to the horizontal is also independent of the rake or angle of inclination Ro of the steering output axis to the horizontal. In that sense the steering input and output orientations are uncoupled. Steering output can also reflect an (longitudinal) offset or so-called trail' between projections to the ground of the steered wheel rotational axis and the steering output axis.

The pedal crank axis iSis set (well) forward of the seat at a height to allow ready demount of a rider's stretched forward legs back down to the ground. Known recumbents and semi-recumbents commonly have a high set pedal crank axis, often above a low set seat to suit a more reclined or recumbent rider body position. This for comfort and to promote forward thrust leg action. With a higher set seat, at or slightly albeit below the seat height for a conventional frame, the leg reach of a seated rider dictates a closer, in particular a higher, crank axis position for a given longitudinal position. Conversely, for a given seat height a minimum forward position of the crank axis is dictated by leg reach of a seated rider for a crank axis height allowing ready reach down to the ground.

Leg reach to pedal crank axis aside, a seated rider must (desirably) keep the steering input control within arms reach and hands grasp, without having to lean, hunch, crouch or stoop forward. Some inter-relationship or interchange between steering input control longitudinal position and seat longitudinal position can be admitted. In practice, given the need to preserve drive integrity, the pedal crank axis longitudinal position is less readily changed, so seat longitudinal position is dictated by leg reach. In turn the steering input control longitudinal position is determined by the seat longitudinal position. Similarly, with seat height at a given longitudinal position and again with seat height and steering input control height. An inclined seat mounting ramp, such as one following an rearward upwardly inclined frame arm, is a convenient way of combing reach and height adjustment. A simple linear seat ramp might suffice, but more elaborate profiles could map' a target seat adjustment range. The ramp could follow and even be integrated with the local frame or surmount the frame as an independent form.

An open' (throat)or yoke format frame is convenient for step through to one side, clear of a a pedal crank drive axis forward of the seat. A rectilinear or curved throat profile can be adopted to define and bound the open form. A vestigial frame element could extend rearwards and upwards, possibly in an arc then downwards to wrap the upper circumference of the rear wheel, to carry a seat slide ramp, with an adjustable back rest coupled to the seat or independently mounted upon the ramp. A tapered wedge shaped pannier or storage bag could be interposed between the rear frame upstand and the upper circumference of the rear wheel.

A tubular metal frame with brazed or welded corner joint construction can be adopted, with either straight linear segmented or continuously curved profiled elements.

Extruded elements might be used. Alternatively, a moulded hollow stressed skin monocoque form of synthetic plastics material, such as fibre glass or carbon fibre, could accommodate storage or ancillaries such as elements, say drive batteries and electronic regulator or control modules of an electrical power assist drive. Local wall thickening or reinforcement could be applied at high stress concentration areas such as the pedal crank axis, front wheel mounting, rearward steering drive frame transition and seat mounting.

A continuous curved frame profile would lend itself to or complement a progressive transitional routing path of a flexible drive shaft coupling between steering input control and steering output actuator to a steered road wheel. A linear segmented frame would lend itself to a series of drive shafts with intervening swivel coupling joints. A combination of straight and flexible drive shafts could be used, with complementary frame portions.

The steering arrangement reaches from forward to rearward, to present a steering input control, such as a steering yoke with upturned hand grips at opposite ends, at and toward a rearward seated rider or rather a rearward rider seat position. A steering transfer or transmission between steered (front) wheel and steering input control admits of some variation, but for convenience and simplicity of implementation lies generally above the height of a (steerable) front wheel and between front wheel and rear rider seat. As such it presents a pronounced upper prominent front or forward nose' element as it transitions initially abruptly upward and then canted less acutely rearward. This and the exposed steering couplings themselves contribute a marked particular aesthetic or style feature to the overall cycle form. It is also a feature upon which other elements can be mounted. An example would be forward directed lighting, such as a high intensity LED cluster along with low intensity side markers and/or reflectors.

Within the steering transmission the amount and rate of (change of) steering input in relation to the amount and rate of (change of) steering output is desirably consistent br ease and predictability of steering control. With a transmission taken through an angular displacement or offset, that is with steering output not directly or linearly aligned with steering output, uneven angular accelerations can arise, to counter which so-called constant velocity joints can be lifted in the steering drive. A simpler F-looke type joint could be used for modest angular transitions or where the steering rate is modest, which might be expected in routine straight ahead travel or in modest sweeping directional changes or turns. Paired Hooke joints in succession could provide a combined constant velocity effect or near equivalent.

In one arrangement, the inclination of a steering control input axis, as the last section of the steering transmission presented to a rider, is similar, equates or is parallel to a range of adjustment of a seat, such as through an inclined seat adjustment ramp or rail.

With this relative adjustment of steering control and seat, by movement of either one or both elements, the arm reach and relative forearm and upper arm articulation of a seated rider can be adjusted while the arms remain generally parallel to the steering input axis and the hands can move in a steering control input plane orthogonal to the steering input axis. This means there is no need or tendency to rest weight or lean on the steering control, nor is any shoulder turning movement entailed, so no inadvertent steering input, upon head turning to look fully to one side and/or behind. The rake of the steering input axis can be fixed, such as reflected in the inclination of a rearward upper frame extension, or adjustable, say using bearing carrier slide mounts.

To supplement or substitute for seat adjustment, a telescopic steering input control reach adjustment would allow a reach back(ward) steering to follow longitudinal forward and rearward seat adjustment and generally accommodates different rider body sizes, shapes and proportions along with their individual preferences, albeit an fully-outstretched arm steering action might not be favoured for stability. Similarly, adjustability of steering plane tilt or rake angle could follow change in seat height. A combination or rake and reach adjustability for both steering input and seat disposition could be contrived within a given frame format and size. Some limitation in usable range may a rise from a fixed pedal crank drive axis position. Unlike certain chopper cycles, the reach back steering feature is achievable without compromising the steering output axis, allowing castor and self-centring steering interaction between road wheel and ground.

A reach back steering input control to a more elevated seat than with a recumbent or semi-recumbent will need to clear (above or over) a seated rider's knees, but this is readily accomplished with seat and/or steering control adjustment. An open or closed (framed) yoke with opposed radial arms and hand grip upstands is a convenient steering input control. An inverted yoke orientation could embody hand grip upstands from downwardly canted opposed bars. A wider flatter yoke format provides leverage about the steering axis with minimal downward intrusion into knee and leg space. An inverted V profile yoke with opposed outward and downward splayed depending arms might suit. upstands or down hangers could carry brake levers, drive train gear selectors and other ancillary controls. Hand grips might lie in the steering plane or be slightly canted, say backward, from it, for a more comfortable wrist action in yoke turning.

The steering input angle can be referred to as a steering column rake angle (to the horizontal or vertical) if the steering input control is column mounted. For a final column section upon which a steering input control is mounted, the steering input plane is orthogonal to the control column axis. A rake or trail angle also arises between the steering output axis and the forward offset or lead disposition of a steered wheel axis, typically achieved by a front fork end forward and upward kink. The output steering angle is typically set by a fixed steering carrier head tube set in a frame and whose orientation sets a castor angle. A trail angle also arises where a notional extension of the line of a steerable wheel carrier such as a fork meets the ground ahead of a vertical downward projection of the wheel axis. The relationship between head angle, wheel carrier offset or rake and wheel size impacts upon cycle handling characteristics. In some territories a range of rake and trail angles is stipulated for motorised if not pedal cycles.

A tendency for a wheel to cant, keel, flip' or flop' over sideways upon turning is also associated with a lowering of the front of a cycle when turning from the straight ahead position. With an attendant lowering of centre of gravity, the steered wheel turn continues, at increasing rotational velocity, without rider input. Flop tendency can reduce with wheel speed, as wheel rotational inertia counters the effect. A modest degree of wheel flop tendency or susceptibility can be tolerated in the interests of fast steering response.

Longitudinal seat adjustment affects the weight upon the steered wheel and associated flop susceptibility. Weight shift forward exacerbates the effect. Thus a set back rider seat position and upright stance without need to lean forward upon the handlebars contributes to directional stability. A longer wheelbase can afford greater longitudinal stability, but may prove more ponderous or cumbersome and less manoeuvrable in turns.

Upright cycles commonly have a closed triangulated or diamond braced frame of conjoined linear frame elements. Cantilevered frames with forward and/or rearward frame extensions to carry respectively front or rear wheels are also known for cruiser style cycles. Open, side access or step-through frames with internalised bracing are known for ease of rider side mount and dismount. An open frame with a forward pedal crank disposition can carry the crank axis towards the lower front of the frame before it turns upward to carry a steering transmission. Pedal crank axis could lie longitudinally close to or somewhat forward of a reach back steering input control, as reflected in Figure 3. This unlike a conventional cycle in which the pedal crank sits at the bottom end of a seat support stem, tube or pillar and so is set back considerably from a forward handlebar. A forward pedal crank axis and push forward rather than simply downward pedal drive impact upon balance and stability. Whilst a reach or set backward steering input control does is not called upon to counter or brace any drive reaction forces, a relaxed grip from the rear without weight lean down upon it contributes to balance and stability.

A seat admits of a range of adjustment longitudinally and vertically and can be lower than a similarly adjustable steering input control, as no weight transfer upon the steering is required, unlike a conventional cycle, in which a rider may sit somewhat higher than a handlebar and leans forward to rest hands upon it. A polygonal cranked or continuous curved or curvilinear frame form could sweep down from a mid-height rear seat partly over a rear wheel towards a forward pedal crank then progressively upward and backward to a steering input control. A diversity of rider stance from a sit up and beg' to a laid back' stance could be adopted.

Reach backward steering input control, without reliance upon extravagant rearward handlebar extensions from a fixed steering column dictated by the disposition and inclination of a steering output axis, would be desirable, for compactness of layout and reduced outreach of a riders arms over the full range of steering. Hence the role for an intervening steering transfer coupling transmission between steering input and output, which frees them from close juxtaposition and relative alignment. Thus in a traditional cycle the steering input control is the handlebars, mounted directly upon the steering output of a steering tube carrying front wheel forks. That is the steering input axis is juxtaposed, co-located or coincident with the steering output axis. Input and output are thus inextricably tied, beyond what is necessary for drive transmission.'Liberation' of steering input and output disposition frees up overall cycle layout. This is not realisable with rearward handlebar extension or so-called tiller' steering arm, as reliance is still placed upon handlebar mounting upon a steering tube carrying a steerable wheel.

An elaborate implementation of remote intercouple between steering input and output would be a fly-by-wire' control, with an output actuator commanded through an electrical cable or wireless link by an input control sensor. Some power-assistance or boost could then be imported into the steering output for reduced input force. Vehicle, aircraft or marine remote steering technology could be adapted for this, with a facility to adjust the rate and level of assistance. A steering damper or shock absorber could be incorporated electrically. A variable rate steering, that is power assistance determined by angular displacement. This might be adopted with a modified steering castor action.

Physiologically and ergonomically, a tendency for the shoulders to move upon upper and forearm movement to and I ro in relation to the upper trunk is more pronounced for a traditional handlebars upon which a rider leans forward to rest. In order looking to one side and around behind, there is a limit to the view achievable by head turning about the neck alone. Rather some shoulder turn and upper trunk or torso twist is required.

Physiologically, there is a comfort threshold for a degree of head turn before attendant shoulder turn.

To look around fully with both hands on the handle bars and still seated requires an un-natural contortion of a rider's body. With older, stiffer, less supple rider bodies turning can become more challenging and less readily and likely undertaken, with adverse safety consequences. There is even a limit to that with both hands on a handle bar, so a tendency to release one hand to allow a more uprighT body stance and body turn to the side of the free hand. This places undue reliance upon the remaining grip hand to steer to maintain direction. To get more comfortable with this, a rider may shift buttock placement to one side of a saddle, but weight shift to one side, can provoko an inadvertent turn, unsettle or even de-stabilise the cycle. Longitudinal stability is a function of forward motion and rotational inertia of the wheels, which tends to resist turning and restore position, but a look around to one side and/or directly behind and the turn itself are more safely, predictably and controllably executed at lower speed. A spread arm stance for a wide straight handlebar may impart some braced triangulation to the rider upper body, helpful with steering sitting beneath a rider, but this is less of an issue for offset, reach back remote steering.

Individual plots or maps of ranges of adjustment respectively of steering control input, seat and pedal crank axis can be juxtaposed with overlay ol an ergonomic mannequin to emulate a notional rider in various stances, such as seated with one toot on the ground or seated with feet on opposite pedals. Actual positions of steering, pedals and seat are mutually influenced or inter-related. Thus say, steering reach and seat position longitudinally can address seat to steering arm reach, but is constrained by seat to pedal leg reach. A range of individual rider arm and leg lengths can be accommodated within those adjustability limits. The Applicants envisage what might be encapsulated as both a laid back' and look behind' cycle, conveniently designated by the acronyms LBC.

Turning a cycle can start with a rider lean in the direction of the intended turn, which can be initiated, provoked or promoted by a modest turn of a steered front wheel initially away from the turn to provoke a sideways tip over into the turn, before being maintained by a movement of the steering input control into the intended turn. The responsiveness or immediacy of the steering output reaction to control input reflects the steerable front wheel output steering axis, trail or castor angle.

A steering input plane orthogonal to a rider's (fore) arms, and/or parallel to a line between the shoulders, allows steering input by turning a steering input control by rotation in the input plane, by to and fro or upward and downward movement of a riders arms, without necessitating shoulder or upper trunk turn or twist. Conversely, a seated rider can turn to look around to one side and/or behind without inadvertent steering control rotational input or inadvertent turn initiation. At or just beyond the boundaries of the range of steering input plane inclination some modest intercouple between rider turn and steering input might be tolerated, but would be less then for a conventional cycle. Rider weight, at least over and above that of the arms, does not bear upon the steering input control, it does not contribute to or exacerbate steering sensitivity.

An informal or empirical way for a driver to adjust the steering would be firstly to set the seat within reach of the pedals (f pedal position is fixed) and only then, by trial and error, to adjust the steering input plane to allow a rider body twist or turn to the side and around without steering input. An adjustable angle offset handlebar or yoke mounting stem allows some longitudinal reach adjustment by simple rotation of the handle bar or yoke plane. A head turn and neck twist is insufficient for more that a glance to the side over the shoulder, whereas a look behind requires shoulder and wholesale upper trunk twist and turn. Even a head turn risks ride and directional unsettling and instability.

Rider posture impacts upon steering and awareness by looking to the side and around behind. Leaning forward relieves some downward weight of the upper body upon the lower spine, but requires bending or crouching of the spine. Arms, shoulders and upper trunk are strained by loading, as is the neck to allow the head to look upward and forward from a crouched or hunched over forward stance. Steering responsiveness or sensitivity can be adjusted, such as through the (front or forward) steerable wheel trail angle to reflect that rider weight no longer bears directly upon the steering input control, as a rider sits and can lean back in a seat, rather than leaning forward as with a conventional cycle.

In a seated steering stance some weight is also relieved as a whole from the front wheel, with an impact upon ground contact and traction. The (seated) balance of total weight distribution is shifted from the front to the rear, or rather is no longer shifted forward when a rider leans forward to steer as a rider can steer without leaning forward.

To compensate rider seat disposition in relation to the wheel base can be brought forward and/or different sized front and rear wheels can be used. Thus, say, a smaller front wheel can engender a nose down, weight shifted forward disposition. The steerable (front) wheel steering output axis angle may also be adjusted to reflect the laid back seated steering stance or kept as for a conventional cycle with lean forward steering. A rider could chose to lean forward on a steering input control, but is not encouraged or obliged to do so by the overall cycle format.

A continuous curvilinear ribbon, band or strip frame format might be adopted with an integrated forward control column support, intermediate pedal carrier and rearward seat and backrest. Elements of known motor scooter construction reflecting (such as the Vespa brand) this might be adopted. The seat and backrest could transit the frame profile, such as through a sliding surface fit. Thus, for a curvilinear or wavy frame both upward and downward and fore and aft adjustment is encompassed. A mid-set or intermediate span frame section could serve as a foot rest, as with a motor scooter, but the frame width would be constrained to allow lower legs and feet to straddle either side or to mount opposed pedals upon a crank axis carried by the frame. A fabricated, stamped or pressed sheet metal or extruded metal or plastics section could be used for the frame. A strip frame could incorporate a stiffener rib profile, such as a mid-section and/or side edge upstand or downturn.

The seat and backrest could allow continual rider positional adjustment, consistent with natural physiology and to obviate continuous loading of the spine through sitting or leaning, especially the lower back. This helps promotes circulation and joint suppleness.

Aside from any longitudinal adjustment in a steering column mounting, the steering yoke itself might feature some fore and aft adjustment, such as through out fold or infold pivot or flex of handle upstands or hangars. This could also allow adjustment of yoke width or span. The handles themselves could also be extendible or articulated to allow re-orientation for conformity with a rider hand grip.

Although a unitary or integrated stressed skin monocoque moulded open frame format is convenient for stiffness and rigidity, a modest framen bending flex of opposite ends about an open throat frame could impart some ride cushion or softening action, without unsettling a rider, whilst preserving wheel mounting and running geometry. Frame stiffness could be adjusted by adoption of a frame section with a self-braced profile such as rib upstand or a recess, channel or groove, or multiple juxtaposed such local profile features. The hollow or in-filled diamond or trapezoindal lonzenge frame cross-section profiles of Figure 15 can be sized accordingly.

A cluster of lesser and different section tubes may be used internally or externally to build up a bespoke frame sectional profile of a more complex curved outer surface form and to contribute greater cumulative stiffness. A frame section which varies along the frame, such as one whether relative proportions of depth and width interchange, could be adopted for bespoke stiffness. Asymmetry and non-uniformity of frame section could provide bespoke performance, such as differential rigidity or flex in the horizontal and vertical planes. An elastomeric or fluid-filled frame section could contribute self-damping local restorative flex. A deformable internal partition wall or membrane fitted within a hollow frame containment might be adopted for a certain self-damping frame flex. Fluid might flow between hollow frame chambers, through a controllable section through-passage, as a mass transfer cushion damping action.

A demountable, triangular side elevation or tapered wedge form carrier bag or pannier could fit between a frame tail upstand and rear wheel. The bag could hang from the frame and/or feature a longitudinal pocket or sleeve to receive the frame section.

The various geometry, configuration, reach-back steering and other features of the invention as reflected in the foregoing disclosure and appendant claims, could be applied to cycles with more than two wheels, such as tricycles and quadricycles, or even unicycles with stabiliser wheels.

Component List cycle 11 seat 12 steering input control 13 backrest 14 podal crank pedal crank axis 17 front wheel 18 frame 19 rear wheel 21 steering column 22 flexible coupling 23 articulated joint 27 front wheel axis 29 rear wheel