Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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~A~KGRO~ND OF THE IN~ENTION:
The present invention is related to a two-wheeled
vehicle, such as a motor bicycle.
This application is a divisional application of
Canadian Patent Application Serial No. 321,624, filed
February 16, 1979.
Generally, the present invention provides a
frameless two-wheeled vehicle, such as a motor bicycle,
comprising a motor assembly including a motor, a front
assembly including a steerable front wheel having a
horizontal axis, movable front linking means for linking
the front assembly to the motor assembly, a rear assembly
including a rear wheel, movable rear linking means for
linking the rear assembly to the motor assembly, and a
steering assembly linked to the front-assembly and connected
to the motor assembly.
~; One important feature of the vehicle, or motor
bicycle according to this invention resides in the fact
that its motor constitutes the frame of the vehicle and
thus forms an organ adapted to transmit directly the
static and dynamic forces between the front part and the
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rear part of the vehicle. Due to the fact that the
conventional frame structure is no longer used in the
novel vehicle, the weight of the latter is considerably
reduced and its centre of gravity is lowered to an e~tent
unknown in the prior art.
The invention relates to a frameless two-wheeléd
motor vehicle, comprising front and rear sub-assemblies
directly attached to a central sub-assembly; the central
sub-assembly comprising a motor, a linking member secured
to the motor, and a gear-box; the front sub-assembly
comprising the front wheeI of the vehicle, a front axle
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upon which the front wheel is rotationally mounted, front
wheel suspension means, front wheel braking means, and
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front wheel steering means; the rear sub-assembly comprising
the rear wheel of the vehicle, a rear axle upon which the rear
wheel is rotationally mounted, rear wheel suspension means,
and rear wheel braking means, the rear wheel suspension
means comprising (i) an H-shaped fork having two forward
arms connected to the motor and two rearward arms for
supporting the axle, (ii) an arm having one end pivotally
connected to a lower part of the linking member, and
another end, (iii) damping spring means having an upper
- end pivotally attached to an upper part of the linking
member and a lower end pivotally attached to the other
end of the arm, and (iv) a first rod member having one
end pivotally connected to the lower end of the damping
spring means and another end pivotally connected to at
least one of the rearward arms of the H-shaped fork.
The front suspension of a motor bicycle according
to the invention has a substantially quadrilateral shape,
the four corners of which are defined by the ends of two
arms hingedly connected by one of their respective ends to
a plate integral with the motor, while the other end of
each arm is hingedly connected to a triangular piece or
element supporting the axle of the front wheel.
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More particularly, the two arms are both pivotally
connected to the plate by means of pivots perpendicular
to the plate, and to the triangular element by means of
pivots adapted to permit the angular motion of the triangular
element about a common axis of the pivots, the latter being
furthermore mounted on ball-and-socket joints so as to be
able to swing or oscillate, in response to the displacement
of the suspension, about an axis passing through the centre
of each ball-and-socket joint and perpendicular to the plane
of displacement which contains the the corners of the
quadrilateral. The leng~hs and the initial position of the
sides of the ~uadrilateral determine the shape of
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the curve defined, during the displacement of the front suspension, by the
centre of the front wheel in a geometrical vertical plane which also encompassesthe centre of the rear wheel. When suitable parameters have been chosen, it
is possible to center the above-mentioned curve with respect to the rear-wheel
centre. Thus the wheel-base of the vehicle, which is equal to the distance
between the wheel centres, is constant. Due to this arrangement, and due to
other features which will be described in detail herein-after, the vehicle is
maintained in a substantially perfect horizontal position during brakins,
whereby the so-called "salutation reaction" is efficiently a~oided.
10It is furthermore possible to adjust the suspension, due to the fact that
the upper one and/or the'lower one of the above-mentioned arms are connected, -~
respectively, to the p;vots, by means of screws and bolts which allow the
length of the arms to be varied.
The front sus?ension of the motor bicycle or similar vehicle is maintained
in the desired position by a damping spring attached by one of its ends to
the lower arm and by its other end to an upwardly extending beak formed by
the plate. It will be understood that by appropriately selecting the length
of the spring and the location of the point of connection or attachment of its
lower end~ it is poss;ble to adjust the height of the centre of gravity within
extremely wide limits. Consequently the principle of the invention can be
applied to any type of vehicle , especially motor bicycles, whether they are
designed for purposes of competition, sport, ordinary use, or whether they
are meant to be used on tracks, on the road or on rough ground.
;The steering assembly of the motor bicycle according to the invention
comprises a handle-bar, a bracket having a ver~ical rod ~hich is rotatably
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n10unted in a ~ube supported by a tripod integrally mounted on the motor, on
the upper side there of, a substankially vertically extendina control rod
connected by universal joints to said bracket, on the one handg and, on the
other hand, to the end of one a~l of an angle-piece the other arm of which
S forms a fork, a link mernber provided at each one of its ends with an eye,
the ;nside of each eye being provided with a ball-and-socket-joint bushing
and connected to a pivot extending throu~h a fork located at the end of a
lever integral with the triangular element. It is obvious that any one of
the elements constituting this steering assembly may be provided with clearance
increasing or compensating means known per se adapted to allow any appropriate
adjustment to be effected.
It will also be noted that it is also poss~ble, to simplify the steering
assembly by aligning the tube, in which the above-mentioned bracket.iS rotatablymounted, on the axis of the control rod~ whereby the uppermost universal joint
becomes unnecessary and can thus be omitted. The steerin~ is then rendered
still smoother and more precise.
According to one feature of the invention, the triangular element supports
- a brake control device provided with a disc located in the nnedian plane o~ the
front wheel. Such a.rrangement is rendere~ possible by the fact that the front
wheel is mounted in an cantil.evered mannerand that the wheel-disc can be dishedon the side opposite to the suspension. This arran~ement is highly advantageous
in that ik suppresses any dissyr,lmetry oF the reactions during brakins and it
renders unnecessary any reflex of the user with a view to correct;ng the tra- ;
jectory of the vehicle while actuating the front wheel brake.
Thus the front wheel suspension is associated both to a steering assembly
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and the front-wheel braking means, the thus associated elements constituting
a self-contained front sub-assembly wherein the forces and efFects of inter-
action are fully withstood and balanced.
Similarly the rear part of the vehicle is also constituted by a self-
contained sub-assembly capable of wit.hstanding by itself the various forces
acting on, and transmitted by, the elements of this rear sub-assembly com-
prising the rear-wheel proper, the rear-wheel suspension and the rear-wheel
braking means, said suspension comprising a fork the arms of which are con-
nected, on the one hand, to the hub of the wheel and, on the other hand, to
a connecting piece adapted to attach the rear sub-assembly to the motor.
The rear part of the vehicle also presents the advantages brought about by
the invention due to the fact that the fork which supports the rear wheel is
substant;ally H-shaped, two arms of said fork being connected to linking
pieces integral with the motor, or to bosses provided on the motor, while
IS the other two arms of said H-shaped fork support the rear wheel hub.
~ In one embodiment of the invention the rear wheel suspension comprises
a damp;ng spr1ng having an upper end connected to the top end of the connec-
ting piece integral with the motor, and a lower end connected to one end of
an arm the other end of which is hingedly connected to the bottom end of
~20 said connecting piece, said damping spring being furthermore connected to
one end of a rod member, the other end of which is attached to the fork.
With a view to further reducing the so-called "salutation reaction", the
lower end of the damping spring is attached through another rod member to a
beak extending forwardly frorn the plate supporting the disc brake, said plate
being mounted so as to be able to rotate about the rear wheel hub. Thus
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whenever the rear wheel brake is actuated, said rod member, on the one hand,
limits the amplitude of the rearward displacement of the brake support and,
on the other hand, acts on the lowermost attachment point of the sprin~ so
as to compress the same, ~hereby the suspension is "stiffened". In this res-
pect it will also be understood that by conveniently selecting the variousparameters, such as the length of the rod members and the location of the
attachment points~ the braking reaction effect exerted on the suspension can
be varied.
Thus the motor bicycle according to the invention is novel in that it is
constituted by the combination of three self-contained sub-assemblies, namely:
a central sub-assembly comprising the motor and a ~ear-box, a front sub-assem-
bly comprising the front wheel, guiding elements for said front wheel, the
front wheel suspension braking means associated with the front wheel and
steering means associated with the front wheel, and a rear sub-assembly com-
prising the rear wheel, the suspension associated therewith and braking meansfor said rear wheel, the front sub-assembly and the rear sub-assembly being
connected to each other by the central sub-assembly to which they are direc-
tly attached.
In one embodiment of the invention the front sub-assembly comprises guiding
elements having substantially the shape of quadrilateral the four cornersof
which are defined by the ends of two arms,one of their respective ends is
hingedly connected to a linking plate attached to the central sub-assembly,
while said two arms are connected at their other ends by ball-and-socket
Joints to a triansular piece which supports the axle of the front wheel.
In another embodiment the front wheel suspension is maintained in its
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desired position by a damping spring one end of which is attached to the
lower arm o~ the front sub-assembly, the other end of said damping spring
being attached to an upwardly extendin~ beak formed by the linking piece or
element of the sub-assembly.
In fact, the instantaneous centre o~ rotation of the front wheel is always
located behind the ax;s of the rear wheel and below the horizontal plane con-
taining the centre of gravity of the vehicle.
The self-contained nature of the sub-assemblies constituting the present
motor bicycle allows, in particular, each one of said sub-assemblies to be
adjusted in accordance with specific requirements, without it being necessary
to take into account the other sub-assemblies while effecting such adjustments
on a given sub-assembly, since each sub-assembly is capable, due to its
design, of absorbing by itself the forces wh;ch are exerted on it by its
various constituent elements.
The self-contained nature of the sub-assemblies obviously Facilitates not
only their adjustment, but also their manufacture, whereby the motor bicycle
according to the invention lends itself particularly to be mass-produced.
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Due to their self-contained structure, the sub-assemblies may furthermore
be constructed in such a manner that they are between them selves ;nterchan-
geable for example, one g;ven type of front sub-assembly can be associated
with central sub-assemblies (i.e. motors) of various HP ratings, while it is
also poss;ble tD provide the tatter with interchangeable rear sub-assemblies.
It will be understood that a great number of combinations can thus be
~ achieved.
It is obvious that in the case of damage occurring to the vehicle,
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the repair work is greatly facilitated, as each of the sub-assemblies is
directly accessible.
Furthermore, it has been shown that due to the design of the front wheel
suspension, it is possible to displace rearwardly the portion of the travel-
ling curve of the instantaneous centre of rotation, which corresponds to thedisplacement of the centre of the wheel with respect to the entire vehicle
under the action of various loads.
The vehicle according to the invention comprises means for adjusting the
length of the front wheel suspension arms, whereby the adjustment parameters
~10 can be modified easily and rapidly.
According to one feature of the invention the instantaneous centre of
rotation of the front wheel is located behind the axis of the rear wheel and
below the hori~ontal plane containing the centre of gravity of the motor bi-
cycle.
In the present disclosure, the term "centre of gravity of the motor bicycle
(or vehicle)" designates the centre of gravity of the entirety constituted by
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- the motor bicycle plus its driver'
; The invention will be described in more detail herein-below with reference
~ to the appended drawings which are given by way of illustration, but not of
llmitation.
In the drawings:
Fig. 1 shows a motor b;cycle according to the invention, as seen from the
left side.
Fig. ~ is a schematic side-elevational view of the front suspension.
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25 F~g. 3 is r schematic perspective view of the steering elemerts.
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Fig. 4 shows, in perspectivel the front wheel suspension and the front
wheel brake.
Fig. 5 shows the motor bicycle according to the invention as seen from
the right side.
Fig. 6 schematically shows the adjustment of the front suspension of the
motor bicycle according to the invention.
The motor bicycle shown in Fig. 1 comprises a motor designated generally
by reference numeral 1. In the present example, the motor is a transversely
rnounted four-cylinder in-line motor~ it will be understood, however, that any
other type of motor could also be used. At its front end the motor 1 is pro-
vided with a plate 4 integrally fixed on the motor, said plate can be replaced
by any appropriate protuberance obtained directly when moulding the motor block.Said plate 4 supports two pivots 8 and 9 extending perpendicularly to the
plane of the drawing shown in Fig. 2, two arms 2 and 3 being hingedly connec-
ted to said pivots in such a manner that said arms are able to effect a rota-
tional motion about said pivots in a plane parallel to the plane of Fig. 2.
The ends of these arms support pivots 10 and 11 having a common axis 101
about which pivots a triangular element 5 wh;ch supports the axle 6 of the
front wheel 7. It will be seen that pivots 10 and 11 are able to carry out
angular or rotational movements in the plane of Fig. 2, alon~ circles the
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centres of which are defined by pivots 8 and 9, respectively, when the sus-
pension enters into action.
Fig. 2 shows the suspension in its rest position wherein arms 2 and 3 are
in their lowermost position. The Figure also shows, with an exaggerated angle
of angular displacement, the position of the front wheel suspension when submitted
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to a heavy load. Under these conditions, pivots 10 and 11 are displaced to
the locations designated by reference numerals 10' and 1l', respectively;
the arms are shown, in this position, by heavy lines extending between loca-
tion 10' and pivot 8, on the one hand, and between location 11' and pivot 9,
S on the other hand. During this upwardly directed displacen~ent of the arms,
the acute angle formed by axis 101 and the lower arm 3 tends to widen;
this also applies to the distance between axle 6 and pivot 9. The trajection
path followed by axle 6 during this disp~acement may be considered as being
approximately circular, especially on account of the small ~Jalue of the am-
plitude of the angular displacements of the suspension; the curve defined bythis trajection path may thus be considered as constituting a segment of a
circle. By apprbpriately selectins the respective locations of the above-
mentioned elements 8, 9, 10 and 11, it is possible to define this circular
curve in such a manner that its geometrical centre coincides w;th the rear
wheel centre, and the radius of said circular curve, which constitutes at
the same time a precise measure of the wheel-base of the vehicle, is then
constant.
- It is also possible to provide, between pivot 8 and arm 2, a rod member
~81 bearing a screw, the length of which rod member is adjustable, such rod
member can also be provided between arm 3 and pivot 9. Such arrangement is
particularly advantageous in the case of experimental vehicles, because it
allows the determination of def;nite parameters for production vehicles to
be accelerated.
The front wheel suspens;on is maintained in its desired position by a
-25 damping spring 12 one end of which is attached to lever 3, and the other end
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of which is attached to an upwardly extending beak 13 formed by plate 4.
Fig. 3 shows the steering elements of the vehicle. These steering ele-
ments comprise a handle-bar 14, a bracket 15 having a vertical arm which
is rotatably mounted in a tube 16 supported by a tripod 161 integrally
connected to the upper part of motor 1, a substantially vertically ex-
tending control rod 17 attached by universal joints 171 and 172 to bracket
15, on the one hand, and, on the other hand, to the end of one arm of an
angle-piece 18 the other arm of which forms a fork l9, a link member 20
each one of the ends of which is provided with an eye, the inside of each
eye being prov;ded with a ball-and-socket joint bushing and connected to a
pivot extending through a ~ork 21 located at the end of a lever 22 integral
with triangular element 5.
Fig. 4 shows a braking device generally des;gnated by reference numeral
23, which braking device, or brake control device 23 acts on a disc 24.
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Since the wheel 7 is mounted itl an cantileveredposition, disc24 can be lo-
cated in the median plane of said wheel.
As shown in Fi~. 5, fork 25 supporting rear wheel 26 is substantially
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H-shaped so as to deflne two arms 27, 2~ which are attached to linking
; pieces 29, 30 integrally connected to the motor 1 or to bosses provided
on motor 1, sald fork 25 also defining two other arms 31, 32 which support
the rear wheel hub; furthermore a damping spring 33 is provided, the upper
end of which is attached to the upper part of the linking piece 29 integral
with the rotor, while the lower end of said spring is attached to one end
of an arm 42the other e~d of which is hingedly connected to the lower part
of said linking piece 29; damping sprin~ 33 also is connected to one end of
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a rod member 39 the other end of which is connected to fork 25. Furthermore,
the lowermost end of damping sprin~ 33 is connected through another rod memker
40 to a beak 34 extending forwardly from the plate 35 which supports the
braking device 36 comprising a disc 37, said plate 35 being able to be angu~
larly displaced about the rear wheel hub.
The instantaneous centre of rotation CIR of front wheel 7 (cf. Fig. 6)
- which front wheel is suspended by arms 2 and 3 hingedly connected, respec-
tively, to triangular piece 6 supporting the wheel, and to plate 4 integral
with the motor (not shown here) - is located behind the centre 38 of the
rear wheel and below the vertical plane P containing the centre of gravity
CG of the vehicle as defined herein-before.
Thus the instanteneous centre of rotation CIR is located w;thin the
hatched zane in Fig. 6, when the various elements of the veh;cle according
to the invention are properly adjusted, as described herein-above.
It will be noted that the vehicle or motor bicycle accordlng to the
;nvention is advantageous, i.a., in that its weight is very low with respect
to its horse-power ratin~, and also in that its centre of gravity is consi-
derably lower than that o-f all known motor bicycles; furthermore, the elimi-
nation of the frame and the fork will obviously result in a considerable
reduction of the manufacturing cost of the vehicle. It should also be
remembered that any reduction in the weight of a vehicle entails a correlative
decrease of fuel consumption.
The invention is not limited to the embodiments shown and described;
numerous modifications may be envisaged by those skilled in the art within
~25 the scope of the invention as defined in the appended claims.
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