GB2082987A

GB2082987A - Three-wheel Cambering Vehicles

Info

Publication number: GB2082987A
Application number: GB8120259A
Authority: GB
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1980-08-29
Filing date: 1981-07-01
Publication date: 1982-03-17
Also published as: GB2082987B; JPS6052030B2; JPS6099779A; CA1158175A; JPS5777276A; JPS6110352B2

Abstract

A three wheel motor cycle has a main frame 70 supporting a front steering column 96, the main frame being pivotally mounted on a rear support frame 14 for left and right tilting movements, and an engine 18 forming a part of the rear support driving the rear wheels 20, 22; an operator's seat 112 is supported over the rear frame on an extension of the main frame, and operator footrests are directly supported on the rear frame to increase the ability of the operator to balance the cycle. The mounting of the footrests is such that they are automatically tilted in response to tilting movements of the main frame. <IMAGE>

Description

SPECIFICATION Three-Wheel Cambering Vehicles This invention relates to three-wheel cambering vehicles.

In our prior patent application No. 8104094 there is disclosed a three-wheel cambering vehicle having a central cambering frame to which is fixed a steering column and a dirigible engine-driven wheel at the front of the vehicle and an operator support seat at the rear of the vehicle. A stable platform supported immediately above the ground by laterally spaced rear wheels receives the feet of the operator and rockably supports the cambering frame. With this vehicular construction, the operator, while sitting or standing, can impart natural balancing moments to the cambering frame and steering column of the vehicle through his feet, using the stable platform in effect as a moving ground to provide reaction.The operator may, accordingly, maintain vehicle balance while the vehicle is stationary or when cornering through a wide range of vehicle speeds with the cambering frame leaned and balanced as the turns are executed. In the vehicle disclosed in the prior application, the steering column supports the engine, the front wheel is engine-driven, and the platform is disposed over a rearwardly extending portion of the cambering frame, which in turn is disposed immediately above the support surface. The vehicle disclosed in the prior application performed as intended but would not provide a particularly suitable basis for a three-wheel motorcycle configuration with rear wheel drive.

In the specification of United Kingdom patent application No. 2 014 094A (Jephcott) there is disclosed a three-wheel cambering vehicle comprising a front steering fork assembly rotatable about an inclined steering axis, a steerable front road wheel mounted on the lower extremity of the fork assembly for rotation about an axis transverse to the steering axis, manual steering means fixed to an upper portion of the fork assembly, a cambering main frame having a forward support mounting the steering fork assembly for pivotal movement about the steering axis, a rear frame pivotally supporting the cambering frame for left and right cambering movement about a central roll axis, a pair of laterally spaced road wheels operatively supporting the rear frame, and an engine forming a portion of the rear frame and operative to drive the rear wheels, the cambering frame having an extension fixed thereto extending rearwardly over the rear frame.

By the present invention there is provided a three-wheel cambering vehicle comprising a front steering fork assembly rotatable about an inclined steering axis, a steerable front road wheel mounted on the lower extremity of the fork assembly for rotation about an axis transverse to the steering axis, manual steering means fixed to an upper portion of the fork assembly, a cambering main frame having a forward support mounting the steering fork assembly for pivotal movement about the steering axis, a rear frame pivotally supporting the cambering frame for left and wight cambering movement about a central roll axis, a pair of laterally spaced road wheels operatively supporting the rear frame, and an engine forming a portion of the rear frame and operative to drive the rear wheels, the cambering frame having an extension fixed thereto extending rearwardly over the rear frame, characterised in that a seat is disposed on the extension for supporting a vehicle operator, and laterally spaced footrest means are supported directly by the rear frame for receiving the feet of the operator when seated on the seat, to permit the operator to directly use the rear frame as ground reaction and thereby instinctively balance the main frame when cambered.

In a specific arrangement of a three-wheel cambering vehicle in accordance with the present invention, a three-track motorcycle includes a rear frame and an engine uniquely arranged and coupled together into an assembly to form a rear support for the rear drive wheels suspended thereto through spring and shock absorber units.

Mounted for left and right leaning movement to either side of the longitudinal axis of the vehicle and the rear support (rear frame plus the engine) is a main cambering frame which supports the vehicle operator, and optionally a passenger, above the engine and drive wheels. The main cambering frame extends forwardly from the axial pivot connections with the rear support to a steering head that pivotally carries a steering column assembly with the dirigible front wheel The cambering frame carries a seat for the operator, and the rear support carries laterally spaced footrests disposed on opposite sides of the cambering frame.With this construction an operator can sit upon the cambering main frame and, by the action of his left and right feet on the laterally spaced foot rests, impress instinctive balancing moments on the cambering frame to improve stability during cornering and for balancing when the vehicle is stationary. With this arrangement, vehicle balancing can be accomplished with reduced effort since the engine is supported in a fixed relationship with respect to the cambering frame. Also, there is improved traction since the operator, seated above the engine and drive wheels, can readily shift his body weight with respect to the drive wheels.

In the drawings: Figure 1 is a side elevational view with parts removed of one embodiment of a three-wheel cambering vehicle (motorcycle) in accordance with the present invention; Figure 2 is a top plan view of the cambering vehicle of Figure 1 on the line 2-2 of Figure 1, in the direction of the arrows; Figure 3 is a fragmentary cross-sectional view of control components of the cambering vehicle of Figure 1 generally on the line 3-3 of Figure 1.

in the direction of the arrows; Figure 4 is a rear view of the cambering vehicle of this invention on the line 4-4 of Figure 1, in the direction of the arrows; Figure 5 is a front perspective view of the cambering vehicle of Figure 1, showing the cambering of the main frame; Figure 6 is a front view of the cambering vehicle of Figure 1 on the line 6-6 of Figure 1, in the direction of the arrows; Figure 7 is a diagrammatic illustration of a cambering footrest of the cambering vehicle of Figure 1; and Figure 8 is a top perspective view of the cambering vehicle of Figure 1, illustrating the cambering of the main frame.

In the drawings, there is shown a three-wheel motorcycle 1 2 providing a narrow track, highly manoeuvrable and stable vehicle for an operator and, optionally, for a passenger seated in tandem.

This vehicle has a longitudinally oriented and fixed rear frame 14 that arches upwardly from a central, inclined rear pin 1 6 into connection, through a threaded fastener 17, with an upper portion of an internal combustion engine 1 8. With the rear frame and engine integrally coupled to one another, a rear carriage support platform of this vehicle is formed.

In addition to forming a structural part of the vehicle, the engine drives laterally spaced rear wheels 20, 22 through a chain 24, a differential not shown, and laterally extending axle shafts 26.

The differential and axle shafts are operatively mounted in a stepped cylindrical housing 28 which extends laterally and with clearance through the arch of the rear frame 14 and which rotatably mounts laterally spaced rear drive wheels 20, 22 at the outboard ends thereof.

Rigidly attached to the front of the engine is a laterally extending cross tube 32, the outboard ends of which are connected to left and right forwardly extending outrigger tubes 34 and 36 that respectively operatively support operator footrests 38 and 40.

The differential and axle housing 28 is secured to the rearward end of a pair of swing suspension arms 42 and 44 laterally disposed from one another and respectively located inboard of the rear wheels 20, 22. The forward ends of these suspension arms are mounted for independent swinging movement on laterally extending pins 46 and 48. These pins are supported in an intermediate position on arms 50 and 52 of a chain adjustment bracket assembly 54. The upper ends of arms 50, 52 are pivoted to the rear frame 14 by a pivot shaft 56 which extends laterally through the rear frame. The lower ends of arms 50, 52 are connected by a cross arm which extends through an adjustment slot 60.

Adjustment screw 62 threadedly mounted in the rear frame 14 is operatively connected to the cross arm of the bracket assembly so that arms 50, 52 can be precisely turned with respect to pivot shaft 56 to move the differential and axle housing forwardly or rearwardly to thereby adjust the tension on the drive chain 24. Locking nuts 64 threadedly mounted on the lower ends of arms 50, 52 are employed to maintain these arms in a selected position.

Laterally spaced suspension spring and shock absorber units 66 and 68 operatively interconnect the rear frame 14 and the differential and axle housing 28 to form the hydraulically damped spring suspension between the drive wheels 20, 22 and the rear support platform to provide for a smooth vehicle ride and good handling characteristics.

This invention features a central, longitudinally extending cambering frame 70 which is mounted for left and right cambering motions or roll with respect to the roll axis 71 of the vehicle and to the rear frame and engine. The cambering frame has an inverted U-shaped back portion 72 which arches over the rear frame 14. The rear leg 74 of this back portion is rockably supported on rear pin 1 6 while the forward leg 76 thereof is rockably supported on a central forward pin 78 projecting from cross tube 32 which has inclined alignment with the pivot pin 1 6 so that the roll axis 71 of the cambering frame intersects the center of the contact patch (foot print) 82 which the dirigible forward wheel 84 imprints on support surfaces 86.

The cambering frame 70 has a lower front support tube 88 generally inclined upwardly from pin 78 and has a top support tube 90 extending forwardly from an upper portion of the forward leg 76 of the frame. These tubes intersect in a steering head 92 set at a predetermined and rearwardly inclined rake angle for the support of a steering pin 94.

A conventional dual bar front fork or steering assembly 96 is pivotally mounted on steering pin 94 for steering movements with respect to the front steering axis. The lower end of the steering assembly 96 rotatably mounts the front wheel 84 on axle 95. The upper end of the steering column assembly is operatively connected to handlebars 98 on which handgrips 100 and 102 are operatively mounted. The handgrip 100 is conventionally connected through a cable to the throttle valve of the engine. By manual turning of this grip to selected positions, throttle valve opening is accordingly set for control of engine speeds. Manual lever 104 mounted on the handlebars adjacent the grip 100 is operatively connected to the front brakes and is manually actuated by the vehicle operator when braking is desired. Hand lever 106 mounted on the handlebars adjacent the grip 102 is operatively connected to the engine clutch and is manually actuated for clutch control when shifting gears.

The handlebar mounted controls are conventional, and can be readily actuated by a vehicle operator seated immediately behind fuel tank 110 on forward seat 112 of a seat assembly fixed by brackets 114 and other fastener provision, not shown, to the back portion of the cambering frame. The seat assembly includes a passenger seat 11 6 immediately behind the operator seat 11 2. The feet of a passenger seated on seat 116 rest on pegs 118 and 120 respectively secured to the rear ends of outrigger tubes 34 and 36 by fixed brackets 137. The feet of the operator respectively engage footrests 38 and 40 as previously stated. Instead of being fixed, as with the passenger's foot pegs, the operator's footrests 38 and 40 rotate with respect to the axis of corresponding outrigger tubes 34 and 36 in response to the cambering of frame 70.

Figures 3 and 7 best illustrate the rolling or cambering of the operator footrests. Footrest 38 is attached to the forward end of an inner tube 124 which is rotatably mounted by suitable bearings in outrigger tube 34. The back end of the inner tube has a lever arm 126 fixed thereto which is connected through link 128 and spherical pivot joints 130 and 132 to the forward leg 76 of the cambering frame 70. In the same manner, footrest 40 is connected to the leg 76 by tube 1 38 rotatable within outrigger tube 36, lever arm 140, link 142, and pivots 144 and 146. With such construction, the footrests 38 and 40 camber with the main cambering frame as diagrammatically illustrated by Figure 7 so that the operator's feet maintain a fixed position with respect to his body when the operator cambers the frame 70 and his body in executing corners.

This ensures that the operator can efficiently and effectively impart instinctive balancing load to the footrest when cambering without any appreciable foot slippage to thereby provide improved cambering control.

Immediately forward of footrest 38 is a rear brake pedal 1 50 having a lower end connected by pivot 1 52 to an axially movable actuator rod 1 54 centrally mounted through tube 124. Support arms 1 56 and 1 58 operatively connect the pedal 1 50 for pivotal movement with respect to support pivot 160, coaxial with footrest 38, when pedal 1 50 is depressed by the vehicle operator. The back end of the actuator rod 1 54 is pivotally connected to a lever system 1 59 that in turn is connected by pulley and cable system 1 60 to the rear brakes of the vehicle.By depressing the pedal 150, the rod pulley and cable system will be actuated to turn the brake arms 1 62, 1 64 so that shoe brakes in the drums of the rear wheels will be actuated for rear wheel braking. A gear shift pedal 1 66 is mounted on the outrigger tube 36 in a similar manner to that of the rear brake pedal for manual operation of a conventional transmission gear shift mechanism, not shown. Lever 170 is a camber lock which in the position shown in Figure 1 engages a recess in the engine for locking the vehicle in the standing pOsition. When cambering, this camber lock will be moved to permit the cambering frame to be cambered as indicated above. A cylindrical engine muffler and exhaust 1 72 is operatively mounted at the rear of the vehicle as shown.

With this invention, a vehicle operator can be seated upon the vehicle when stationary and impress instincitve balancing loads to the footrests 38 and 40 so that the vehicle is maintained in an upright position without the operator's feet touching the vehicle supporting surface. When the vehicle is being driven, cornering and other cambering manoeuvres can be readily accomplished with the operator imparting balancing loads to the footrests 38 and 40, which tilt in direction and degree corresponding to degree of camber. This balancing is through the feet and legs of the operator, and is a natural reaction which does not require any auxiliary balancing mechanism. Thus, if the operator is executing a sharp right turn, the operator can readily camber the cambering frame, as the rear carriage of the vehicle remains in fixed angular relationship to the supporting ground.The cambering frame, when leaned to the right side of the cambering axis, can be balanced by loads impressed on the tilted footrests 38. In a similar manner, stabilized cambered left cornering can be accomplished. With the operator seated on the cambering frame immediately above the fixed frame and engine, traction is improved, and vehicle manoeuvres are effective for cornering at wide speed ranges and through narrow roadways.

Furthermore, with this invention, the cambering and fixed frame arrangement provides for improved access to the suspension components as well as the engine.

The three-wheel cambering vehicle which has been described thereby represents a new and improved narrow-track, three-wheel vehicle having an upper cambering main frame operatively supporting the vehicle operator and a steerable front wheel, and also having a lower rear platform on which laterally spaced rear wheels are mounted that tend to remain in a plane generally fixed with respect to the ground during vehicle manoeuvre.

Claims

1. A three-wheel cambering vehicle comprising a front steering fork assembly rotatable about an inclined steering axis, a steerable front road wheel mounted on the lower extremity of the fork assembly for rotation about an axis transverse to the steering axis, manual steering means fixed to an upper portion of the fork assembly, a cambering main frame having a forward support mounting the steering fork assembly for pivotal movement about the steering axis, a rear frame pivotally supporting the cambering frame for left and right cambering movement about a central roll axis, a pair of laterally spaced road wheels operatively supporting the rear frame, and an engine forming a portion of the rear frame and operative to drive the rear wheels, the cambering frame having an extension fixed thereto extending rearwardly over the rear frame, a seat on the extension for supporting a vehicle operator, and laterally spaced footrest means supported directly by the rear frame for receiving the feet of the operator when seated on the seat, to permit the operator to directly use the rear frame as ground reaction and thereby instinctively balance the main frame when cambered.

2. A three-wheel cambering vehicle according to claim 1, in which the front steering fork assembly is operatively mounted along the longitudinal axis of the vehicle and extends upwardly from a surface supporting the vehicle, and the roll axis is inclined and is coplanar with the longitudinal axis of the vehicle.

3. A three-wheel cambering vehicle according to claim 1 or 2, in which the laterally spaced footrest means are operatively connected to the cambering main frame for cambering movement therewith, to permit the operator to directly impart manual balancing moments to the cambering main frame to manually hold the main frame in equilibrium when cambered and thereby stabilize vehicle operation.

4. A three-wheel cambering vehicle according to claim 3, in which an elongate support is coupled to the engine and extends transversely of the longitudinal axis of said vehicle, a pair of forwardly extending tubes are attached to the outboard ends of the elongate support, and linkage means operatively connect the footrest means at the forward ends of the tubes to the cambering main frame to cause the footrest means to tilt in accordance with the direction and degree that the main frame is cambered.

5. A three-wheel cambering vehicle substantially as hereinbefore particularly described and as shown in the accompanying drawings.