Note: Descriptions are shown in the official language in which they were submitted.
CA 02350437 2001-05-10
SCOOtAr
The present invention relates to a scooter according to the generic clause of
claim 1.
Such travel devices arse preferably used by children and young persons, vn the
one hand as
a means of locomotion and, on the other hand, as a sports requisite or simply
as a pastime
and for pleasure. Scooters are primarily regarded as a toy device for small
children, but
scooters have also become known which are intended for adults as a means of
locomotion
in the downtown areas of big cities.
A travel device of the type mentioned in the generic clause of claim 1 is
known from
W095l344B1. The collapsible scoot~r has a rigid footboard. According to a
special em-
bodiment, a central part of the footboard extends on a lower level than the
ends of the foot-
boara_
US-A-4,179,133 discloses a means with the aid of which a roller board can be
converted
into a scooter.
Scooters are predominantly used on sidewalks. The surface of such areas
serving as a
track are normally of a firm nature, e.g. tarred or paved, sometimes they are,
however, also
covered with slabs. Quite large surface irregularities are not uncommon. Since
the travel
devices of the above-mentioned kind have unsprung wheels, the bumps produced
when the
travel device is moving are felt to be very unpl~asant by th~ users of such
travel devices.
The handling properties of scooters differ depending on the respective
structural design of
these travel devices.
DE-A-2820934 discloses a skateboard provided with a brake mechanism. The
braking
means prevents the skateboard from rolling in the unloaded condition. When the
middle of
the skateboard has a load applied thereto, the brake will be released due to a
deformation
of the footboard of the skateboard. By purposefully applying a stronger load
to the flexible
and springy footboard whon the skateboard is moving, a purposeful braking
effect can be
achieved.
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CA 02350437 2001-05-10
2
WO 98/4544 discloses a collapsible treadle scooter comprising essentially a
front running
gear carrier which supports a single wheel and which has foldably connected
therato a
steering handle, a footboard and a rear-wheel axle with two wheels, said rear-
wheel axle
being secured below the footboard. According to a preferred embodiment, the
footboard
may consist of a front and a rear part, the two parts being interconnected via
a joint. The
joint may consist of a sflock-absorbing material. Part of tile footboard can
be implemented
such that it is elastic.
It is the object of the present invention to provide a scooter having improved
handling prop-
~rties.
This object is achieved by the subject matter of claim 1. Preferred further
developments of
the present invention represent the subject matters of the subclaims.
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CA 02350437 2001-05-10
3
In the following, one embodiment of the present invention will be explained in
detail making
reference to the drawing, in which:
Fig. 1 shows a diagram of a roller board,
Fig. 2 shows a section through a footboard,
Fig. 3 shows a single running gear,
Fig. 4 shows a tap view of a further embodiment of a running gear,
Fig. 5 shows the same embodiment in a schematic side view,
Fig. 6 shows a diagram of a modified running gear during straight-on
travelling.
Fig. 7 shows a diagram of this running gear during cornering and
Fig. 8 shows a section through a damper.
In Fig_ 1 reference numeral 1 stands for a footboard connected to a front
running gear 2 on
one side and to a rear running gear 3 on the other side thereof. In the
example shown, the
two running gears 2 and 3 are identical. Each of the running gears 2 and 3
consists of a
support 4, a wheel holder 5 connected thereto and at least one wheel 6 which
is rotatably
supported in said wheel holder 5. The wheels 6 may, for example, be rollers
having the
shape of a cylinder of the type normally used in the case of roller boarrJs
according to the
prior an~ In such a case, the wheel holder 5 accommodates two wheels 6 which
are ro-
tatable about a common axis.
According to the present invention, the footboard 1 is releasably connected to
the running
gears 2, 3. It is therefore possible to replace one of the running gears 2, 3
by another one
having a different structural design or to replace both running gears 2, 3 by
running gears
CA 02350437 2001-05-10
4
having a different structural design. It is, for example, possible to use a
front running gear 2
in the cas~ of which the axle about which the wheels 6 rotate is pivotable,
whereas a run-
ning gear having a different structural design, viz. e.g. a fixed axle, is
used as a rear running
gear 3.
According to the present invention, the footboard 1 is, in addition,
constructed such that it
will resiliently yield under load, said load being caused by the user's weight
which acts on
the footboard 1 when such a roller board is in use. When, as is normally the
case, the foot-
board 1 is acted upon by the weight of a person approximately in the middle
thereof, the
elastic deflection will advantageously be approx 2 to 3 cm. In thi it i way
achieved that
bumps caused by ground-surFace irregularities will be compensated far
comparatively
smoothly by elastic deflection so that these bumps will act on the user in a
very mild farm.
This will create a pleasant feeling when the travel d~vice is moving.
By means of the present invention it is achieved that such a travel device can
easily be
adapted to the user's needs. It is, for example, possible to replace a
footboard 1 by another
footboard 1. A first structural design of a footboard 1 has dimensions which
are adapted
e.g_ to the measurements and the weight of an adult, whet~as a second
structural design of
a footboard 1 is adapted to the measurements and the weight of a child. The
adaptation to
different measurements and different weights is, on the one hand, effected by
varying the
dimensions of the footboard 1, viz. the length, the width and the thickness.
Each of these
three dimensions also influences the elastic deflection. A further variation
possibility i5 the
use of different materials for the footboard 1. For example, Beth plastic
material and multi-
layered, glued wood are adapted to be used as a material for the footboard.
Far the elastic
deflection as a function of weight also the modulus of elasticity of the
material is of essential
importance_
The dimensions of variants of the footboard 1 should be chosen depending on
the require-
ments to be satisfied. The length ranges between 50 and 80 cm, the width
ranges betty~en
12 and 18 cm, whereas the thickness may range between 8 and 25 mm, the
thickness de-
pending primarily on the mater5al used and on the medulus of elasticity of
slid material.
It will be particularly advantageous when the material used for the footboard
1 is a multi
layered, glued wood which is known under the designation plywood_ This
material is char
CA 02350437 2001-05-10
acterized in that, on the one hand, it is able to resist comparatively high
loads and that, on
the other hand, it has remarkable vibration damping properties. This has the
effect that such
a footboard 1 acts a shack absorber.
CA 02350437 2001-05-10
6
Also plastic materials have good damping properties, According to an
advantageous em-
bodiment, the footboard 1 may therefore also consist of plastic material. when
a material
belonging to this group of materials is used, the footboard 1 can be
implemented as a box.
It will be of advantage when the material and the dimensions of the footboard
1 are chosen
such that a spring rate of e.g. 0.1 mm/kg is obtained. When the footboard 1
has applied
thereto a load of 30 kg approximately in the middle thereof, the elastic
deflection will be 3
mm. It is, however, also possible to realise "harder" footboards 1 having a
spring rate of
e.g. 0.03 mmlkg or "softer" footboards 1 having a spring rate of e.g. 0.25
mmlkg. If the foot-
board 1 is implemented as a box, as has been mentioned hereinbefore, it will
be possitJle to
insert reinforcement struts into individual cavities according to an
advantageous embodi-
ment. With the aid of such reinforcement struts , the spring rate can be
changed subse-
quently so as to adapt it to the user's Wishes. Such a variability of the
spring rate can be
realized also in the case of other embodiments; in a footboard 1 made of
plywood, which is
shown in Fig. 2, the spring rate can be varied e.g. by providing both
longitudinal sides of the
footboard with grooves N which are adapted to have reinforcement struts 5
inserted therein,
The variation of the spring rate by introducing reinforcement struts 5 has the
advantage that
it is not necessary to provide a plurality of different footboards 1. This
will reduce the variety
of variants. without any necessity of giving up the advantage ofi different
spring rates.
The running gears 2, 3 have a slot 7 into which the footboard 1 can be
inserted so that said
running gears 2, 3 can be connected to the footboard 1 in a simple manner. The
connection
between the running gears 2, 3 and the footboard 1 is fixed e.g. by means of
screws which
are not shown in the figure 1.
In Flg. 3 a single running gear 2 is shown. It consists analogously of a
support 4 having a
slot 7 for inserting a footboard 1 which is not shown in this figure. The
fastening means, e.g.
screws, are not shown either. Other than in the case of the example according
to Fig. 1, the
wheel 6 is here not arranged below the support ~., but it is arranged in a
mode of arrange-
ment that is normally used in the case of scooters, viz. in such a way that a
rear part of the
support 4 is implemented as a fork 8 in which an axle 9, about which the wheel
6 rotates, is
secured in position. In this case, the wheel 6 does not have the shape of a
cylinder after the
fashion of skateboards, but it will be of advantage when said wheel has a
structural design
of the type used for the wheels of inline skates.
CA 02350437 2001-05-10
7
Fig. 4 snows a further embodiment of a running gear 2. This is a steerable
running gear 2
with two wheels, which, due to its steerabifity, is particularly suitable for
use as a front run-
ning gear.
Fig. 4 shows, outlined by broken lines, a part of the footboard 1 which is
fixed in the slot 7 of
the support 4 by two screws 10. At the front end 11 of the support d located
opposite the
slot 7, two hinges are provided, viz. a left support hinge 12 and a right
support hinge 13. A
left jvumal 1a is pivotable about said Isft support hinge 12 and a right
journal 15 is pivotable
about said right support hinge 13 in a corresponding manner. The possible
pivotal movo-
ment about the support hinges 12, 13 is marked with arrows. The ends of the
two journals
14, 15 located opposite the support hinges 12 and 13 are provided with hinges
16 through
which these ends are connected to a track rod 17_ It follows that the
connecting line be-
tween the two support hinges 12, ~ 3 together with the two journals 14, 15 and
the track rod
17 define a parallelogram. By means of said track rod 17 it is achieved that
the two journals
14, 15 are coupled to one another so that they can only be pivoted
simultaneously. The IEft
journal 14 has rigidly secured thereto a left whoel axle 18 about the other
end of which a left
front wheel 19 is freely rotatable, e.g. by means of a ball bearing which is
not shown. In the
same way, the right journal 15 has secured thereto a right whe~I axle 20 about
the other
end of which a right front wheel Z1 is freely rotatable, i.e. each of said
front wheels 19, 21
has a sgparste wheel axle 18, 20 so that an independent wheel suspension is
obtained.
The pivotal movement of the two journals 14, 15 has the effect that the wheel
axles 18, 20,
which are rigidly connected to said journals 14, 15 , are pivoted through the
same angle as
the journals 14, 15 . Also the front wheels 19, 21 are pivoted
correspondingly. In the repre-
sentation according to Fig. 4, the two front wheels 19, 21 are positioned
parallel to the lon-
gitudinal axis of the whole travel device, a position which results in
straight-on travailing. If
one of the two journals 14, 15 is deflected clockwise e.g. by 15° in
comparison with the
CA 02350437 2001-05-10
8
position shown in the drawing - due to the coupling rod 17, this will have the
effect that also
the otherjoumal 15, 14 is deflected in the same way - the front wheels 19, 21
will assume a
position at which they are inclined at an oblique angle to the right in such a
way that they
are also deflected by 15° relative to the longitudinal axis of the
travel device. The travel
device would then take a curve to the right.
Steering of such a construction can be pertormed in different ways. For
example, the track
rod 17 may have secured thereto a driving pin 22 that is movable by means of a
steering
handle, which is not shown, in the directions designated with broken-line
arrows.
In the following an embodiment is described in the case of which a steering
handle can be
dispensed with. The fundamental arrangement corresponds to that which has just
been de-
scribed. The essential aspect, however, is that the axes of the support hinges
12, 13 and
the hinges 16 are markedly inclined relative to the vertical, as can clearly
be seen in Fig. 4
which shows a side view from the right, the components shown in Fig. 4 being
provided with
the same reference numerals.
The right front wheel 21, which is in principle visible in this side view, is
here only shown in
the form of its contour line so that the view of the parts located behind said
front wheel is
not obstructed. Behind this front wheel 21 the right journal 15 can be seen.
This jaumal 15
has rigidly secured thereto the right wheel axle 20. In this view, sold right
wheel axle 20
extends at right angles to the plane of projection, i.e. only the diameter
thereof is Visible. As
far as the right support hinge 13 (Fig. 4) is concerned, which is not visible
in Fig. 5, only the
axis of rotation A,3 of said support hinge is shown here. The axis of rotation
A,~ of the left
support hinge 12 (Fig. 4) is located behind A,3, i.e. it is not visible
either. The axis of the
hinges 16 is designated by A,6.The angle between the two axes of rotation A,2,
A,3 of the
support hinges 12, 13 and the vertical is preferably approx. 20 to 60°;
a value of 47° proved
to be the optimum value. It follows that the axes of rotation A,Z, A,s of the
support hinges 12,
13 are inclined at an oblique angle in such a way that, on the one hand, they
extend paral-
lel to an ideal surface which extends at right angles to a centre line M (Fig.
4) of the foot-
board 1 and of the whole travel device, respectively, and that, on the other
hand, they ex-
tend from the front top to the rear bottom. The axes of rotation A,B of the of
tt~e hinges 16
are inclined in the same way, the track rod 17 rotating about said hinges 16
rolative to the
two journals 14, 15, when said journals 14, 15 rotate about the support hinges
12, 13 in
the direction marked by arrows in Fig. 3.
CA 02350437 2001-05-10
9
The marked inclination of the axes of rotation A,2, A,3, A,e of the above-
mentioned paral-
lelogram consisting of the connecting line of the support hinges 12, ~ 3, the
journals 14, ~ 5
and the track rod 17 has the effect that the wheel axles 18, 20 secured to the
journals 14,
15 will extend horizontally only if the journals 14, 15 define an angle of
precisely 90' rela-
tive to the connecting line of the suppork hinges 12, 13 in accordance with
the representa-
tion shown in Fig. d. At this position the wheel axles 18, 20 additionally
extend at an angle
of precisely 90° relative to the centre line M of the footboard 1 and
of the whose travel de-
vice, respectively; hence, the front wheels 19, 21 will, in turn, extend
parallel to this centre
tine. This corresponds to straight-on travelling of the travel device.
By means of the above-mentioned embodiment it is achieved that the wheel axles
18, 20
and the journals 14, 15 are pivoted away from the position of straight-on
travelling as soon
as the footboard 1 has applied thereto a heavier load on one side thereof; in
the present
context, on one side means that the ideal load application point is located on
the right- or on
the left-hand side of the imaginary centre line M.
Let us assume that the ideal load application point on the footboard 1 is
located on the
right-hand side of the centre line M, as shown in Fig. 4. The ideal load
application point is
designated by reference symbol L. This load application has automatically the
effect that
the right front wheel 21 has applied thereto a heavier load than the left
front wheel 19. This
also has the effect that the front wheel 21 applies a perpendicularly
effective force to the
right front axle 2o which, in turn, applies a force to the right journal 15.
In view of the fact
that the respective counterforces acting on the left front wheel 19, the left
front axle 18 and
the left journal 14 decrease at the same time, the journals 1 a, ~ 5 wilt -
because of the
oblique position of the axes of rotation A12, A13 of the support hinges 12, 13
- be rotated
clockwise to a certain extent about the axes of rotation A12, A13 of the
support hinges 12,
13, the track rod 17 will be displaced correspondingly and the front axles 18,
20 with the
front wheels 19, 21 connected thereto as well as the journals 14, 15 will move
correspond-
ingly. Such a position is shown in Fig. 4 by a dotted line. The right front
axle 20 now ex-
tends rearwards at a slightly oblique angle, and simultaneously it also
extends upwards at a
slightly oblique angle. In addition, the left front axle 18 extends forwards
at a slightly oblique
angle, and simultaneously is also extends downwards at a slightly oblique
angle. Accord-
ingly, the front wheels 7 9. 21 assume a slightly oblique position with regard
to both axles;
for the sake of clarity, this is, however, not shown in Fig. 4 with respect to
the upward and
downward inclination. It follows that, in relation to the footboard 1,
5~.1~5 ~'iTU~~ S~~~T
CA 02350437 2001-05-10
1
the right front wheel 21 is positioned on a slightly higher level and the left
front wheel 19
on a slightly lower level. When the two front wheels 19, 21 are placed on a
flat ground
surface, the footboard 1 will therefore be inclined about the centre line M~
in such a way
that its right edge is located slightly closer to the ground surface, whereas
the distance
between the left edge and the ground surtace is slightly larger. In view of
the fact that the
front wheels 19, 21 assume a slightly oblique position in the case of this
steering
construction, it will be of advantage when they do not have a cylindrical
troad, but also these
front wheels should have a structural design of the type used for inline
skates.
Hence, the user of the travel device can control the direction of movement
simply by shifting
his weight. A steering handle is not necessary. This shifting of weight can
take place in dlf
ferent ways. The user may, for example, place one foot on the footboard 1 at a
laterally dis-
placed position, but he may also incline his body.
In the case of a travel device having this type of structural design, it may
be of advantage
when straight-on travelilng is stabilized by special measures. Fig. 6 and 7
schematically
show an embodiment which corresponds to the above-mentioned running gear to a
very
large extent. Also in the case of this running gear, journals 14, 95 are
provided, which are
adapted to be rotated about support hinges 12, 13 on the ane hand, and which
are con-
netted to a track rod 17 on the other hand, said track rod 17 being connected
to the jour-
nals 14, 15 by means of hinges 16. This track rod 17 is adapted to be
displaced in the di-
rection marked by an arrow. (n the case of this running gear variant, a
resetting device is
provided, which is provided with a stop 30 that is fcxedly secured to the
front end 11 of the
support 4. The track rod 17 has secured thereto a holder 31 close to each of
the two ends
thereof. Two dampers 32 are arranged on the track rod 17 such that they are
displaceable
thereon, one of said dampers 32 being located on one side of the stop 30,
whereas the
other damper 32 is arranged on the other side of said stop 30. Each damper 32
comprise]
a fast perforated disc 33 and a second perforated disc 34 as welt as a ring 35
which is ar-
ranged between said perforated discs 33, 34. The internal diameters of said
perforated
discs 33, 34 are larger than the diameter of the track rod 17 so that said
perforated discs
CA 02350437 2001-05-10
11
are freely movable relative to said track rod 17. The ring 35 is, however,
dimensioned such
that its interior diameter is slightly smaller than the diameter of the track
rod 17. Hence,
said ring 35 produc~s a sliding friction on the track rod 17.
Compression springs 36 are arranged between the dampers 32 and the holders 31.
It will
be advantageous to pretension the compression springs 36 between the damper 32
and the
holder 31. By means of this pretension, the stop 30 will be caused'to remain
at a central
posilaon corresponding to straight-on travelling without the influence of any
other force, as
can be seen from Fig. 6. If the user of the travel device shifts his weight on
the footboard 1,
the pretension of one of the compression springs 36 first has to be overcome
before a de-
fection of the wheels can occur. Fig. 7 shows this arrangement in a condition
of strong de-
flection of the wheels. One of the compression springs 36 is here under no
stress at all,
whereas the other compression spring 36 is strongly compressed. By means of
this ar-
rangement it is achieved that the user must shift his weight against one of
the compression
springs 36. As has turned out in tests, this will specially improve the
sensitive steerability of
the travel device.
It will be particularly advantageous when the friction produced by the dampers
32 is vari-
able. This is achieved in an advantageous manner in that the diameter of the
track rod 17 is
not constant over the whole I~ngth, but that the track rod 17 has the largest
diameter in the
middle, whereas the diameter decreases towards the two ends thereof. When the
running
gear occupi~s the straight-on travelling position, which is shown in Fig. 6,
the rings 35 will
be expanded more strongly by the larger diameter which the track rod 17 has in
the central
area thereof, and this will result in strong friction. When the wheels of the
running gear are,
however, deflected to a higher degree, as can b~ seen in Fig. 7, one of the
rings 35 of one
of the dampers 32 will longitudinally be displaced by the stop 30 relative to
the track rod 17
to such an extent that this ring 35 will occupy a position at which the
diameter of the track
rod 17 is smaller. The sliding friction will be correspondingly Lower. Alsv
this measure
serves to improve the steerability by the user.
The ring 35 should advantageously consist of a rubber-elastic material. The
perforated
discs 33. 34 should advantageously consist of plastic material; this has the
advantage that
irritating noise will be avoided when the dampers 32 come into contact with
the stop 30.
CA 02350437 2001-05-10
12
It will be advantageous when the damping effect that can be produced by the
sliding friction
is variable. This can be achieved in a particularly simple manner by an
embodiment shown
in Fig. 8. Fig. 8 shows a section through a damper 32 which is displaceable on
the track rod
17. The section has been made through the ring 35. The ring 35 is encompassed
by a
shackle 38. This shackle 38 is, in the manner known, provided with an
adjusting screw 39
by means of which the shackle 38 can be fastened more or less tightly. When
the shackle
38 is tightened only slightly, the ring 35 will be compressed only slightly.
Hence, the friction
of said ring on th~ track rod 17 will not be high. When the shackle 38 is
fastened more
tightly, the ring 35 will be compressed more strongly so that th~ friction
will be increased. In
this way, it is achieved in an advantageous manner that straight-on travelling
will be stabi-
lized to a higher degree at higher speeds and in the case of uneven ground
surtaces.
The above-mentioned solution making use of the shackle 38 is to be regarded as
only one
possible embodiment. Other solutions producing the same effect, e.g. after the
fashion of a
stuffing box having a variable pretension, are equivalent to this embodiment.
Foatboards 7 having various structura~ designs can be combined with diff~rent
running
gears 2, 3 within the framework of the present invention. Hence. the travel
device can be
given completely different handling properties depending on the footboarLi 1
and the run-
ning gears 2, 3 used.
