Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02242709 1998-06-08
WHEEL EXAMINING APPARATUS
This application is a division of Canadian
application Serial No. 2,046,240-0 filed July 4, 1991.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention generally relates to a wheel
examining apparatus for examining a wheel,, in particular
its alignment, such as the degree of inclination of a
wheel, of a vehicle, such as an automobile, truck or
trailer, and, in particular to a wheel examining apparatus
for examining a wheel having a double wheel or double tire
structure comprised of a pair of sub-wheels combined
side-by-side for supporting a heavy load.
2. Description of the Prior Art
A wheel examining apparatus for examining the
alignment or mounting condition of a wheel of an
automobile, bus, truck, trailer or the like has been
used. Various conditions are set in a wheel mounted on a
vehicle and in particular the so-called inclination
angles, such as toe angles, camber angles and caster
angles are set in a wheel regarding its running
performance. These inclination angles are examined once
as one item of examination of a vehicle before the vehicle
is shipped after manufacture, and they are also examined
when an maintenance operation, such as exchange of wheels,
is to be carried out for a vehicle after a period of use.
In order for a vehicle to have an
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excellent running performance, it is important that these
inclination angles be properly set and maintained. In
addition, as a dynamic characteristic of a wheel, or a
characteristic of a wheel while the wheel is in rotation,
such parameters as wobbling of a wheel to the left and to
the right and steered angle of a wheel are important.
Since the running performance of a vehicle can be
significantly affected by such a dynamic characteristic
of wheels, it is quite important that the dynamic
characteristic of a wheel can be measured at high
accuracy. Moreover, there are those vehicles which use
the so-called double wheel or double tire comprised of a
pair of sub-wheels fixedly mounted side-by-side so as to
increase the ability to support a heavier load. Since
the stability of such a heavy duty vehicle is extremely
important from the view point of safety in driving, it is
also important that examination of such a double tire can
be carried out properly and accurately.
Japanese Pat. Laid-open Pub. Nos. 51-83301 and
54-49701 disclose techni~ues for measuring the toe angle
and/or camber angle of a wheel while the wheel is
maintained in rotation. However, according to the
teachings of these prior art techniques, although a wheel
to be examined is supported on a pair of rollers to keep
in rotation, either of the side surfaces of the wheel is
not supported or a contact roller is brought into rolling
... . . . ... . . ..
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contact with one side surface of the wheel to take
measurements and the geometrical center of a wheel as an
object to be measured is not located or determined by
clamping the wheel from both sides, so that accurate
measurements cannot be taken. On the other hand,
Japanese Pat. Appln. Nos. 58-109235 and 59-9502 and Pat.
Laid-open Pub. No. 61-41913 disclose techniques for
locating or determining the geometrical center of a wheel
supported on a floating table by clamping the wheel from
both sides. However, according to these techniques,
since the wheel supported on the floating table is static
and non-rotating, there is no way to measure the dynamic
characteristic of the wheel.
Japanese Pat. Laid-open Pub. No. 63-286742
discloses a wheel examining apparatus capable of
measuring the dynamic characteristic of a wheel while
keeping the wheel in rotation under the condition of
clamping the wheel from both'sides. According to the
teachings of this prior art reference, since a wheel is
supported on a pair of rollers and the wheel is clamped
by rollers at its opposite side surfaces, the dynamic
measurement of a wheel can be carried out. However, the
apparatus disclosed in this reference is suited mainly
for examination of a wheel mounted on a four-wheel
vehicle having two axles. Accordingly, the apparatus of
the above-described prior art reference is not always
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satisfactory, in particular, for heavy load vehicles,
such as larger-sized automobiles, trucks, buses and
trailers, which normally have three or more axles and/or
the so-called double wheel comprised of a pair of
sub-wheels mounted side-by-side. For example, there are
needs for improvements in a wheel guiding apparatus for
guiding a wheel to a predetermined location of a wheel
examining appara~us, improvements in examination of wheel
alignment in a multi-axle vehicle having three or more
axles, and improvements in accuracy in measuring the
inclination angle of each of the component wheels in a
double wheel system and in examination of a wheel of a
vehicle suited for carrying heavy loads.
SU~ARY OF THE INVENTION
In accordance with a first aspect of the
present invention, there is provided a wheel guide
apparatus which includes a plurality of guide rollers
arranged in different height levels and thus allows a
wheel to travel along a predetermined path. This wheel
guide apparatus is particularly suited for use in a wheel
examining apparatus for locating a wheel to be examined
at a predetermined location or area in the wheel
examining apparatus. According to this aspect of the
present invention, at least one center roller is
rotatably provided as extending in a direction of
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advancement of a vehicle. Preferably, two or more such
center rollers are arranged symmetrically to the left and
to the right with respect to a predetermined reference
center line. These center rollers are arranged to be
approximately flush with or at a slightly higher level
than a floor surface on which a wheel runs. Thus, while
a wheel rides on these center rollers, a relative lateral
movement betwee-, Lhe wheel on the center rollers and the
main body of a wheel examining apparatus can be provided
with ease substantially in a direction perpendicular to
the advancing direction of the wheel.
A plurality of first side rollers are rotatably
provided at a first height higher in level than the
center rollers and on both sides of the center rollers,
and these first side rollers are arranged to be
convergent in the advancing direction of a wheel so that
the distance between the left and right first side
rollers becomes gradually narrower in the advancing
direction of a wheel. Preferably, these first side
rollers are arranged to be symmetrical with respect to
the predetermined center reference line. In addition, a
plurality of second side rollers are rotatably provided
as located generally outside of the first side rollers
with respect to the reference center line and at a second
height generally higher in level than the first side
rollers. These second side rollers are also arranged to
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be convergent in the advancing direction of a wheel
similarly with the first side rollers. Thus, the first
and second side rollers are inclined such that their
downstream ends come closer together as compared with
their upstream ends with respect to the advancing
direction of a wheel in the wheel guide apparatus.
Preferably, these second guide rollers are also arranged
to be symmetric-al with respect to the predetermined
reference center line.
In a preferred embodiment, at least one
auxiliary roller is rotatably provided at the first
height and in parallel with each of the second side
rollers as being located inside and in close proximity
thereof. The center rollers are preferably arranged
side-by-side in a horizontal plane. On the other hand,
the side rollers are preferably arranged to be inclined
also in a vertical plane such that their downstream ends
are located lower in height than their upstream ends with
respect to the advancing direction of a wheel.
In accordance with a second aspect of the
present invention, there is provided a wheel examining
system for examining a three axle vehicle, which includes
a front wheel ex~m; ning section, an intermediate wheel
examining section and a rear wheel examining section.
Each of these three wheel e~mining sections includes a
pair of wheel examining apparatuses, one for the
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left-hand side wheel and the other for the right-hand
side wheel, which are operatively coupled or
interconnected through an interconnecting or coupling
means such that they are always located symmetrically
with respect to a predetermined reference center line,
which is normally the center line of such a wheel
examining system. The intermediate wheel examining
section and the ~ar wheel examining section are arranged
to be adjacent to each other and in a side-by-side
relation, and the interconnecting means of the
intermediate wheel examining section is arranged in its
rear side with respect to the direction of advancement of
a vehicle in the present system, while the
interconnecting means of the rear wheel examining section
is arranged in the front side with respect to the
direction of advancement of a vehicle. And, the wheel
guide apparatus described above is provided at the
entrance of the rear wheel examining section.
With this structure, the wheels of a three axle
vehicle can be ~YA~i ned individually as well as
simultaneously, and, for example, inclination angles of
all of the wheels can be measured individually and at the
same time. Even if the intermediate wheel examining
section is provided, the overall size of the system can
be minimized because of the distinctive arrangement of
structural components, so that the present system can be
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used for a wider range of vehicles and the area
requirement for installing the present system is
minimized.
Furthermore, in accordance with this aspect of
the present invention, there is provided a wheel
examining system for a three axle vehicle, capable of
examining whether or not all of the tread centers, which
are defined as -~ center between the left-hand and
right-hand side wheels, of the three axles lie on a
common straight line, and capable of effectively
measuring the inclination angle of each of the wheels
even if there is a discrepancy in the alignment of these
tread centers.
That is, the wheel examining system of a three
axle vehicle according to this aspect of the present
invention includes three wheel examining sections for
three axles of a three axle vehicle, respectively, and
each of the wheel examining sections includes a pair of
wheel e~ining apparatuses, one for the left-hand side
wheel of one axle and the other for the right-hand side
wheel of the one axle. Each of the wheel examining
apparatuses also includes an interconnecting means for
interconnecting a pair of ieft and right wheel examining
apparatuses such that the left and right wheel examining
apparatuses are always located symmetrically with respect
to a predetermined center line. In accordance with the
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present invention, two of the three wheel examining
sections have each an interconnecting means whose center
position is always fixed on a frame; whereas, the
interconnecting means of the remaining wheel examining
section has a center position which is movable with
respect to the frame. In a preferred embodiment, the
fixed center position is a center poiht defined on the
frame and the movable center position is a movable center
point movable along a rail mounted on the frame.
In each wheel examining apparatus, the center
of a wheel supported on its supporting means can be
brought into alignment with a predetermined center of the
wheel examining apparatus, which is defined as a center
of a clamping means. In this case, preferably, the
alignment of these two centers is carried out by clamping
the wheel from both sides. As described above, each
left-hand side wheel ex~mining apparatus is
interconnected with an associated right-hand side wheel
examining apparatus, so that these paired left-hand and
right-hand side wheel ~mi~ing apparatuses are always
maintained symmetrical in position with respect to a
predetermined reference center position. In this case,
two of the three interconnecting means have respective
two center positions fixed on the frame and a straight
line connecting these two fixed center positions defines
the reference center line. That is, a center line of a
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wheel to be examined is defined as a straight line
connecting the tread centers on two axles, and this wheel
center line is brought into agreement with the reference
center line of the wheel examining system. The remaining
interconnecting means has a center position which is
shiftable on the frame. In a preferred embodiment, a
rail is mounted on the frame extending in a direction
transverse to th~ reference center line, and a slider is
mounted on the rail to be slidable therealong with the
center position of this interconnecting means is defined
on this slider.
In accordance with a third aspect of the
present invention, there is provided a wheel ex~mining
apparatus including inner and outer contact rollers which
may be brought into contact with the inner and outer side
surfaces of a wheel to have the wheel clamped from both
sides; an inner and outer roller support members
associated with the inner and outer contact rollers,
respectively; and inner and outer angle detectors
associated with the inner and outer roller support
members, respectively. With this structure, since the
inclination angle of each of the inner and outer side
surfaces of a wheel can be measured individually and thus
the inclination angle of a wheel can be measured at high
accuracy.
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In particular, in the case of a wheel having
the so-called double wheel or double tire structure in
which a pair of sub-wheels are mounted side-by-side, it
is often the case that these two sub-wheels are not in
identical in alignment. Even in such a case, since the
inclination angle of each of these sub-wheels can be
measured individually, the inclination angle of a wheel
as a whole having such a double wheel structure can be
properly and accurately measured. Thus, the wheel
examining apparatus according this feature of the present
invention allows to examine a double wheel assembly
accurately and precisely.
In accordance with a fourth feature of the
present invention, there is provided a floating support
lS apparatus capable of setting a floating member, such as a
floating table, for supporting thereon a desired object
with the use of linear motion (LM) guides and rotary
bearings.
In a floating support apparatus according to
this aspect of the present invention, a first straight
guide means is provided at each of at least three
predetermined positions on the surface of a frame, and a
first slider is provided in the first straight guide
means to be slidable in a first direction. A second
straight guide means is provided on the first slider and
extends in a second direction different from the first
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direction. And, a second slider is provided on the
second straight guide means to be slidable in the second
direction. A projection is formed on the second slider.
And, a floating member defining a floating plate is
provided with a rotary bearing corresponding to each of
such projections, and each of the projections is fitted
into a corresponding rotary bearing. Accordingly, the
floating member can freely move in any direction within a
predetermined range in a horizontal surface so that it is
maintained in a floating state.
Preferably, the first and second directions are
set to be orthogonal to each other. Besides, the first
straight guide, the first slider, the second straight
guide and the second slider together define a
bi-directional LM guide, and four of such bi-directional
LM guide are arranged symmetrically. An object
supporting means is provided on the floating member.
Preferably, the ob ject supporting means supports a wheel
of a vehicle, and the floating support apparatus is
incorporated in a wheel examining apparatus so as to
support a wheel to be examined in a floating condition.
With such a floating support apparatus, for example, when
it is applied to a wheel examining apparatus, a wheel can
be securely and stably maintained in a floating state
even if such a wheel is a wheel having a double wheel or
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double tire structure andJor a vehicle is relatively
heavy in weight.
It is therefore a primary object of the present
invention to provide an improved wheel examining
apparatus particularly suitable for use in examining
wheels of large weight vehicles, such as large-sized
automobiles, trucks, buses and trailers, at high
accuracy. - -
Another object of the present invention is to
provide a novel wheel guide apparatus capable of guiding
various types of wheels, including a double wheel, into a
predetermined location or area of a wheel examining
apparatus stably and smoothly.
A further object of the present invention is to
provide a novel wheel examining system particularly
suited for use in examining a tri-axle vehicle including
double wheels or double tires, capable of ~YA~i ning
individual wheels of such a tri-axle vehicle individually
and simultaneously at high accuracy and high speed.
A still further object of the present invention
is to provide a novel wheel ~YA~i ning apparatus capable
of PYArining each of sub-wheels of a double wheel or
double tire assembly individually and simultaneously at
high accuracy and high speed.
A still further object of the present invention
is to provide a novel floating support apparatus capable
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of supporting an object, such as a wheel of a vehicle, in
a floating state movable in any direction in a
predetermined horizontal plane, which is particularly
suitable for use in a wheel support structure in a wheel
examining apparatus.
Other objects, advantages and novel features of
the present invention will become apparent from the
following detail~ description of the invention when
considered in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic illustra~ion showing in
plan view a wheel examining system for examining wheels
of a double-axle vehicle whose rear wheels have a double
- 15 wheel or double tire structure constructed in accordance
with one embodiment of the present invention;
Fig. 2 is a schematic illustration showing in
front view the wheel ~x~mining apparatus shown in Fig. l;
Fig. 3 is a schematic illustration showing in
plan view a wheel exA~ining apparatus provided with a
wheel guide apparatus constructed in accordance with one
embodiment of the present invention provided in the wheel
examining system shown in Figs. 1 and 2;
Fig. 4 is a schematic illustration showing in
side elevation the wheel e~mining apparatus shown in
Fig. 3;
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Fig. 5 is a schematic illustration showing in
front view the wheel examining apparatus shown in Fig. 3;
Fig. 6 is a schematic illustration showing in
plan view a wheel examining system for tri-axle vehicles
constructed in accordance with one embodiment of the
present invention;
Fig. 7 is a schematic illustration showing in
front view the wheel-examining system shown in Fig. 6;
Fig. 8 is a schematic, fragmentary illustration
showing on an enlarged scale the arrangement of the wheel
examining apparatuses for right-hand wheels of both of
intermediate and rear wheels in the wheel examining
system shown in Fig. 6;
Fig. 9 is a schematic illustration showing in
front view the structure shown in Fig. 8;
Fig. 10 is an exploded and perspective view
showing a wheel examining apparatus constructed in
accordance with one embodiment of the present invention
and provided in the wheel examining system shown in Figs.
1 through 6;
Fig. 11 is a schematic illustration showing on
an enlarged scale the arrangement of various components
within a housing of the wheel examining apparatus shown
in Fig. 10;
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Fig. 12 is a schematic illustration showing on
an enlarged scale a part of the structure of the wheel
examining apparatus shown in Fig. 10;
Fig. 13 is a schematic illustration showing in
plan view the detailed structure of a roller clamp
mechanism provided in the wheel examining apparatus shown
in Fig. 10;
Fig. 14-is-a schematic illustration showing in
front view the roller clamp mechanism shown in Fig. 13;
Fig. 15 is a schematic illustration showing in
slde elevation the roller clamp mechanism shown in fig.
13;
Fig. 16 is a schematic illustration showing in
perspective view the overall structure of a support
roller assembly provided in the wheel exAm;ning apparatus
shown in Fig. 10;
Fig. 17 is a schematic illustration showing in
plan view the support roller assembly shown in Fig. 16;
Fig. 18 is a schematic illustration showing in
front view with parts removed the support roller assembly
shown in Fig. 16;
Fig. 19 is a schematic illustration showing in
right-hand side elevation the support roller assembly
shown in Fig. 16;
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Fig. 20 is a schematic illustration showing in
left-hand side elevation the support roller assembly
shown in Fig. 16; and
Fig. 21 is a schem~tic illustration showing a
roller lock apparatus incorporated in the support roller
assembly.
DESCRIPTION OF TH~ PREFERRED EMBODIMENTS
Now, with reference to the accompanying
drawings, the present invention will be described in
detail by way of embodiments.
Referring to Figs. 1 and 2, there is
schematically shown a wheel e~Ami~ing system
constructed in accordance with one embodiment of the
lS present invention, which is particularly suited for use
in examining a double-axle vehicle including left-hand
and right-hand side rear wheels which have the so-called
double wheel or double tire structure. The double wheel
structure is a structure in which a wheel is comprised of
a pair of sub-wheels which are combined together
side-by-side and this type of wheel is normally used in
large weight vehicles. The basic structure of this wheel
examining system is similar to the structure described in
the before-mentioned Japanese Pat. Laid-open Pub. No.
63-286742-
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The present wheel examining system 1 is
disposed in a pit P dug in a floor FL, for example, of a
wheel examining site, and the wheel examining system 1 is
installed as placed on the bottom PB of pit P with its
top surface generally flush with the floor FL. As
indicated by an arrow A in Fig. 1, a wheel to be examined
is driven to run in this direction to be set in the
present system 1~- Since this wheel examining system 1 is
for examining double-axle, and, thus, four-wheel
vehicles, the system 1 generally includes a front wheel
examining section 3f and a rear wheel examining section
3r. The rear wheel examining section 3r is located
spaced apart backwardly from the front wheel examining
section 3f, and, in the present system, in order to be
able to make adjustments for vehicles having different
wheel base distances, the distance between the front and
rear wheel examining sections 3f and 3r can be adjusted
to a desired value. That is, a frame 2 defining the
overall base structure of the present system 1 is
disposed inside the pit P and both of the front and rear
wheel examining sections 3f and 3r are mounted on this
frame 2. The front wheel examining section 3f is fixedly
mounted on the frame 2, but the rear wheel examining
section 3r is mounted on a slider unit 2a which is
slidably mounted on guide rail 2b which in turn is
fixedly mounted on the frame 2 extending in the
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longitudinal direction of the system 1. Thus, the slider
unit 2a may be moved along the guide rails 2b in an
unlocked condition, and after setting a desired distance
between the front wheel examining section 3f and the rear
S wheel examining section 3r, the slider unit 2a may be
locked in position on the frame 2.
The front and rear wheel examining sections 3f
and 3r include a ~air of right-hand and left-hand wheel
examining apparatuses 3fr and 3fl and a pair of
right-hand and left-hand wheel examining apparatuses 3rr
and 3rl, respectively, and these right-hand and left-hand
wheel examining apparatuses are arranged symmetrically
with respect to a center line CL of the system 1. Since
the right-hand and left-hand wheel examining apparatuses,
i.e., 3fr and 3fl or 3rr and 3rl, are symmetrical in
structure, they are substantially identical in structure.
In addition, each of the wheel examining apparatuses 3fr
and 3fl of the front wheel examining section 3f is
substantially identical in structure to each of the wheel
examining apparatuses 3rr and 3rl of the rear wheel
examining section 3r, excepting the fact that each of the
wheel examining apparatuses 3rr and 3rl of the rear wheel
examining section 3f is modified for measuring the
inclination angle of the so-called double wheel assembly.
In the first place, with reference to Figs. 1
and 2, the wheel examining apparatus 3fl (~same for 3fr)
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for a front wheel in the wheel examining system 1 will be
described in detail. The wheel examining apparatus 3fl
includes a pair of support rollers 15f for supporting
thereon a left-hand front wheel Wf, and these support
rollers 15f are disposed in parallel with their rotating
axes extending in a direction substantially perpendicular
to the longitudinal center line CL. The support rollers
l5f are rotatab~y supported, and, in a preferred
embodiment, a motor is incorporated in at least one of
the support rollers to thereby provide a self-driving
structure. If desired, it may be so structured that a
driving force is transmitted to at least one of the
support rollers from an externally provided motor, or the
support rollers may be simply provided to be freely
lS rotatable. In the case of a front wheel driven vehicle,
the front wheel Wf may be driven to rotate on the support
rollers 15f.
A pair of inner lower contact rollers llu and a
pair of outer lower contact rollers lls for detecting a
toe angle or the like are disposed on opposite sides of
the support rollers 15f, and an upper contact roller 72
is provided at the outside of the support rollers 15f for
detecting a camber angle or the like. These contact
rollers.ll and 72 are brought into rolling contact with
the opposite side surfaces of the wheel Wf supported on
the support rollers 15f to have the wheel Wf clamped from
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both sides. Thus, with the opposite side surfaces
clamped by these contact rollers 11 and 72, the wheel Wf
may be set in rotation as riding on the support rollers
15f. In this manner, a dynamic test of the wheel Wf can
be carried out. Although each of the contact rollers ll
and 72 is arranged such that its rotating axis extends
substantially in a radial direction of the wheel Wf, the
inner contact ro~ers llu and the outer contact rollers
lls are not necessarily arranged symmetrically, and, in
the illustrated embodiment, the outer contact rollers lls
are arranged with an angle somewhat larger than the angle
of arrangement of the inner contact rollers llu. The
outer lower contact rollers lls and an upper contact
roller 72 are mounted on a generally triangularly shaped
roller support.
The wheel examining apparatus 3fl includes a
box-shaped base or housing 8, within which is disposed a
clamp mechanism 9 for supporting the inner contact
rollers llu and the outer contact rollers lls movable
closer together or separated away from each other and
rotatable around a vertical axis. As will be made clear
later, the support rollers 15f are rotatably mounted on a
floating member which is supported to be rotatable freely
around a vertical axis and movable translationally in any
horizontal direction within limits. T~us, the support
rollers 15f and the contact rollers ll and 72 are
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provided to be movable relative to each other
independently. The housing 8 is slidably mounted on a
pair of rails 12 which are fixedly attached to the frame
2 and which extend laterally in a direction perpendicular
to the center line CL. Thus, the housing 8 can move in
the lateral direction perpendicular to the center line CL
as guided by the rails 12. However, an arm 6 integrally
provided with the-housing 8 is operatively coupled to one
end of an equalizer 4f. The other end of the equalizer
4f is operatively coupled to an arm 6 of a housing 8 in
the wheel examining apparatus 3fr for the left-hand front
wheel. The equalizer 4f has a center pivotal point which
is always located at the center line CL, so that the
left-hand and right-hand wheel examining apparatuses 3fl
and 3fr are automatically located symmetrically with
respect to the center line CL at all times.
On the other hand, the clamp mechanism 9
disposed inside the housing 8 supports the contact
rollers 11 and 72 to be movable relatively closer
together or separated away from each other and rotatable
around a vertical axis, and the clamp mechanism 9 is
slidably mounted on guide rails disposed inside the
housing 8 and operatively coupled to one end of a
pantagraph 5f through an arm 7. The other end of the
pantagraph 5f is similarly operatively coupled to the
clamp mechanism 9 of the wheel examining apparatus 3fr
CA 02242709 1998-06-08
for the right-hand front wheel through an arm 7. Thus,
the clamp mechanisms 9 of the respective left-hand and
right-hand wheel examining apparatuses 3fr and 3fl are
always automatically located symmetrically with respect
to the center line CL. As a result, once the left-hand
and right-hand wheels Wf have been clamped through the
rollers 11 and 72 through these clamp mechanisms 9, the
locations of geo~etrical centers of respective wheels Wf
are automatically located symmetrically with respect to
the center line CL at all times. Thus, the tread center,
or the center location between the left-hand and
right-hand wheels, becomes automatically aligned with the
center line CL which defines a predetermined reference
line. In addition, an angle detector 30f(preferably, an
encoder) is provided as coupled to the clamp mechanism 9,
so that an inclination angle, such as a toe angle, of
wheel Wf can be measured.
At the entrance of the wheel examining
apparatus 3fl is disposed a wheel guide apparatus, which,
in the present embodiment, includes center rollers 18,
first side rollers 19 and second side rollers 20u. The
center rollers 18 are provided in a pair and they are
arranged in parallel as being partly exposed above the
surface on which the wheel Wf runs and extend in the
direction of advancement of a vehicle. The first side
rollers 19 are rotatably disposed at a first height
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higher in level than the center rollers 18 and they are
arranged to be convergent toward their downstream ends
with respect to the direction of advancement of a
vehicle. The second side rollers 20u are rotatably
supported at a second height higher in level than the
first height and they are also arranged to be convergent
toward their downstream ends with respect to the
direction of advancement of a vehicle. In addition,
adjacent to and somewhat inwardly of each of the second
side rollers 20u is rotatably disposed an auxiliary
roller 201 at the first height. With such a wheel guide
apparatus, a wheel can be guided to a predetermined
location or area accurately, stably and smoothly along a
predetermined path.
Now, referring again Figs. 1 and 2, the rear
wheel examining apparatus 3rl (same for 3rr) will be
described. The rear wheel examining apparatus 3rl is
generally similar in structure to the above-described
front wheel examining apparatus 3fl. In the illustrated
embodiment, the rear wheel examining apparatus 3rl
differs from the above-described front wheel examining
apparatus because it has been particularly modified to
examine a wheel having the so-called double wheel or
double tire structure.
The rear wheel examining apparatus 3rl also
includes inner contact rollers llu and outer contact
- 24 -
CA 02242709 1998-06-08
rollers lls (however, in Fig. 1, these rollers are not
shown because they are enclosed by a cover 17, and, in
Fig. 2, only rollers lls are shown) and a clamp mechanism
(not shown) for supporting these rollers to be able to
move closer together or separated away from each other
and rotatably around a vertical axis. The wheel
examining apparatus 3rl also include6 a box-shaped
housing 8 which-serves as a base and is always
operatively coupled to a similar box-shaped housing 8 of
the other associated wheel examining apparatus 3rr. In
addition, the clamp mechanism disposed in the housings 8
of the respective left-hand and right-hand wheel
examining apparatuses 3rl and 3rr are operatively coupled
through a pantagraph 5r. The housing 8 of the wheel
examining apparatus 3rl is slidably mounted on rails 12
which are fixedly attached to the slider unit 2a on the
frame 2. Thus, the housing 8 may mover in the lateral or
transverse direction as guided by the rails 12.
Furthermore, the wheel examining apparatus 3rl includes a
pair of support rollers l5r which can support a rear
wheel Wr to be examined thereon. In the illustrated
embodiment, since it is expected that the rear wheel Wr
has the so-called double wheel or double tire structure,
the support rollers 15r of the rear wheel examining
apparatus 3rl are longer in the longitudinal direction
CA 02242709 1998-06-08
than the support rollers 15f for the front wheel Wf by
approximately twice.
A wheel guide apparatus constructed in
accordance with one feature of the present invention is
also provided at the entrance of the rear wheel examining
apparatus 3rl. This wheel guide apparatus has a
distinctive structure which is constr~cted such that it
can properly an~ smoothly guide a wheel having the
so-called double wheel or double tire structure onto the
support rollers 15r. This wheel guide apparatus will be
described below in detail with reference to Figs. 3 and 4
as well as Figs. 1 and 2.
The wheel guide apparatus constructed according
to one embodiment of the present invention basically
includes three kinds of guide rollers 18, 19 and 20
disposed at three different height levels, respectively.
In the illustrated embodiment, a pair of center rollers
18 is rotatably provided in parallel with their rotating
axes extending in parallel with the direction of
advancement of a vehicle. In the illustrated embodiment,
the center rollers 18 are arranged symmetrically with
respect to a predetermined reference center line. It is
to be noted the center rollers 18 can be only one or
three or more, if desired. As best shown in Fig. 5, the
center rollers 18 are arranged generally at the same
level with the surface on which the wheels run; however,
- 26 -
CA 02242709 1998-06-08
in a preferred embodiment, the center rollers 18 are
arranged to be partly exposed and thus somewhat project
above the surface on which the wheels run. Thus, when a
wheel runs on the center rollers 18, a relative movement
between the wheel and the wheel guide apparatus can be
provided freely in the lateral or transverse direction,
so that a relative position between the wheel and the
wheel guide apparatus can be determined at a desired
location. The center rollers 18 are preferably arranged
to be in parallel with the horizontal surface.
On both sides of the center rollers 18 are
arranged the first side rollers l9 rotatably. As clear
from Fig. 5, the first side rollers l9 are arranged at
the first height higher in elevation than the center
rollers 18. Moreover, the first side rollers l9 are
arranged such that they are convergent toward their
downstream ends with re~pect to the direction of
advancement of a vehicle through the wheel guide
apparatus, so that the left-hand and right-hand first
side rollers gradually become closer together from their
upstream ends toward their downstream ends. Preferably,
the first side rollers 19 are inclined such that the
angle defined by the left-hand and right-hand first side
rollers would not exceed 30~, and most preferably, this
angle is set around 15~. In addition, in a preferred
embodiment, the distance between the downstream ends of
- 27 -
CA 02242709 1998-06-08
the left-hand and right-hand first side rollers 19, which
is the smallest distance between the left-hand and
right-hand first side rollers 19, is set equal to or
slightly smaller than the width of the front wheel Wf.
If the first side rollers 19 are substantially longer
than the radius of the wheel Wf, the first side rollers
19 are preferably segmented. The length of each of the
segments is preferably set on the order of the radius of
the wheel Wf or smaller. In the illustrated embodiment,
the first side rollers 19 are arranged in parallel with
the horizontal surface; however, if desired, the rollers
19 may also be arranged to be inclined downwardly toward
their downstream ends, in which case the height level of
the first side rollers 19 gradually decrease from their
upstream ends toward their downstream ends. In the
latter case, the angle defined between the horizontal
surface and the first side rollers 19 is preferably set
in a range between 0~ and 15~. In a preferred
embodiment, the left-hand and right-hand first side
rollers 19 are arranged symmetrically with respect to the
center reference line of the center rollers 18.
A plurality of second side rollers 20u are
rotatably provided outwardly of the first side rollers
19. In the illustrated embodiment, the second side
rollers 20u are arranged convergently to define an angle
similar to that of the first side rollers 19; however, if
- 28 -
CA 02242709 1998-06-08
desired, the second side rollers 20u may be arranged with
a lateral inclination to define an angle different from
that of the first side rollers 19. As best shown in Fig.
5, the second side rollers 20u are arranged at the second
S height higher in elevation than the first height. In the
illustrated embodiment, taking the wheel running surface,
which is normally a floor, as a refer,ence, the second
height is approx~mately twice the elevation of the first
height. However, the first and second heights may be set
at any desired levels. Since the second side rollers 20u
are relatively long, they are segmented and each of the
segments has a length which is preferably set to be equal
to or slightly smaller than the radius of the rear wheel
Wr. In addition, the distance between the downstream
ends of the left-hand and right-hand second side rollers
20u is set at a value which is equal to or slightly less
than the width of the rear wheel Wr, which has the
- so-called double wheel or double tire structure in the
illustrated example.
In the illustrated embodiment, a plurality of
auxiliary rollers 201 are also provided and each of the
auxiliary rollers 201 is rotatably arranged adjacent to
and slightly inwardly of its corresponding second side
roller 20u in parallel therewith. As is clear from Fig.
5, the auxiliary rollers 201 are arranged at the first
height and in parallel with the respective corresponding
- 29 -
.. . . . . .. ... . .. . .. ... ....... .. ......... . .. . . ....... .. . ..
CA 02242709 1998-06-08
second side rollers 20u. These auxiliary rollers 201
provide an additional running surface for the rear wheel
Wr having the so-called double wheel or double tire
structure and also an additional guiding function, so
S that the wheel guiding function is significantly
enhanced.
In operation, as shown in Fig. 1, when a
vehicle enters in a direction indicated by the arrow A,
its front wheels Wf are first guided by the respective
wheel guide apparatuses and pass through the'~rear wheel
examining apparatuses 3rl and 3rr. In this case, as
shown in Fig. 5, when the front wheels Wf come into
contact with the second side rollers 20u and auxiliary
rollers 201or the first side rollers 19, the housings 8
move laterally in the direction perpendicular to the
center line CL if there is any discrepancy in positional
relationship between them in the lateral direction. In
this instance, since the left-hand and right-hand
housings 8 are operatively coupled through the common
equalizer 4r, the left-hand and right-hand wheel
examining apparatuses 3rr and 3rl move symmetrically in
- synchronism. In this manner, the left-hand and
right-hand wheel examining apparatuses 3rr and 3rl are
aligned with the respective left and right front wheels
Wf through a cooperation of the present wheel guide
apparatuses as the wheels Wf advance in the direction
- 30 -
CA 02242709 1998-06-08
indicated by the arrow A. Then, as shown in Fig. 5, when
the wheel Wf comes to ride on the center rollers 18,
since a lateral relative movement between the wheel Wf
and the center rollers 18 can be easily provided, the
wheel Wf comes to be more aligned with a corresponding
one of the wheel examining apparatuses 3rr and 3rl. In
this instance, the first side rollers 19 may participate
in bringing the~wheel Wf in alignment with the
corresponding wheel examining apparatus. In particular,
since the left-hand and right-hand first side rollers 19
are arranged inclined and convergent and the distance
between the downstream ends of the left-hand and
right-hand side rollers 19 is set to a value e~ual to or
slightly smaller than the width of the wheel Wf, the
wheel Wf comes to be located substantially at the center
of the support rollers 15r of the wheel examining
apparatus 3rr or 3rl.
As the vehicle advances further in the
direction indicated by the arrow A, the wheels Wf pass
through the rear wheel e~mining apparatuses 3rr and 3rl
In this instance, since the wheel examining apparatuses
3rr and 3rl are locked by a lock device 10, the support
rollers 15r are fixed in position with respect to the
housing 8. Moreover, the support rollers 15r themselves
are locked in a non-rotating state by a roller lock
device 50. Then, the rear right-hand and left-hand
- 31 -
CA 02242709 1998-06-08
wheels Wr of the vehicle enter the rear wheel examining
apparatuses 3rr and 3rl, respectively. It is to be noted
that the rear wheel Wr in this example has the so-called
double wheel or double tire structure, so that, as shown
in Fig. 5, the rear wheel Wr includes a pair of inner and
outer sub-wheels or tires Wrs and Wru which are mounted
on the same axle side-by-side. Thus, when the rear wheel
Wr advances, since its width is larger than the width of
the entrance of the first side rollers 19, the wheel Wr
rides on the first side rollers 19. In this case, if the
rear wheel Wr is shifted in position to the left or
right, the rear wheel Wr first comes into contact with
either of the left-hand and right-hand second side
rollers 20u and/or its associated auxiliary roller 201,
and, thus, the wheel examining apparatuses 3rr and 3rl
are shifted in position sideways symmetrically with
respect to the center line CL so as to bring them in
alignment with the respective rear wheels Wr. Since the
rear wheel Wr rides on the first side rollers 19, a
relative movement between the rear wheel Wr and its
associated wheel examining apparatus 3rr or 3rl can be
provided easily, and, as a result, the positional
alignment between the wheel Wr and its associated wheel
examining apparatus 3rr or 3rl can be carried out
extremely smoothly and stably. Consequently, the wheel
Wr comes to be accurately aligned with a corresponding
- 32 -
CA 02242709 1998-06-08
one of the wheel examining apparatuses 3rr and 3rl with
the aid of the present wheel guide apparatus, so that the
rear wheel Wr is positioned on the corresponding support
rollers 15r in a substantially aligned state.
Now, particularly with reference to Figs. 6
through 9, a wheel ex~mining system for examining the
wheel alignment of a three axle vehicle constructed in
accordance with ~another embodiment of the present
invention will be described in detail below. As shown in
Fig. 6, in this wheel examining system 1, a vehicle to be
examined enters into the system by travelling from the
left to the right in Fig. 6 in the direction indicated by
the arrow A. Since the wheel examining system 1 for
three axle vehicles shown in Figs. 6 through 9 is
structurally similar in many respects to the wheel
examining system 1 for two axle vehicles shown in Figs. 1
and 2, similar elements are indicated by similar
reference numerals. In the present embodiment for three
axle vehicles, in addition to a front wheel examining
section 3f for the front wheels (first axle) and a rear
wheel examining section 3r for the rear wheels (second
axle), an intermediate wheel ex~mining section 3m for the
intermediate wheels (third axle) is also provided. Here,
it is to be noted that the rear and intermediate wheel
examining sections 3r and 3m are so structured to examine
wheels Wr having the so-called double wheel or double
- 33 -
CA 02242709 1998-06-08
tire structure. Thus, the support rollers l5r in each of
these rear and intermediate wheel examining sections 3r
and 3m are structured to have enough width to support
thereon a wheel Wr having such a double wheel or double
tire structure.
As shown in Figs. 6 through 9, the intermediate
wheel examining section 3m is located,adjacent to the
rear wheel exami~Ing~section 3r, and an equalizer 4r and
a pantagraph 5r for operatively coupling a pair of
left-hand and right-hand wheel examining apparatuses 3rr
and 3rl in the rear wheel examining section 3r are
located at the upstream side of the rear wheel examining
section 3r with respect to the direction of advancement
of a vehicle through the system 1 as indicated by the
arrow A. On the other hand, an equalizer 4m and a
pantagraph 5m for operatively coupling a pair of
left-hand and right-hand wheel examining apparatuses 3mr
and 3ml in the intermediate wheel examining section 3m
are located at the downstream side thereof with respect
to the direction of advancement of a vehicle. With this
arrangement, the rear and intermediate wheel examining
sections 3r and 3m can be located closely adjacent to
each other, and yet both of the wheel examining sections
3r and 3m may be constructed relatively low in level.
Although the intermediate and rear wheel
examining sections 3m and 3r are substantially
- 34 -
CA 02242709 1998-06-08
symmetrical in structure with respect to a transverse
line passing through the center between the two sections
3m and 3r, only the rear wheel examining section 3r is
provided with a wheel guide apparatus at its entrance.
Since the intermediate wheel examining section 3m is
provided in parallel with and adjacent to the rear wheel
examining section 3r, it is not necessary to provide such
a wheel guide~ appar-atus to the intermediate wheel
examining section 3m. With such a wheel examining system
for three axle vehicles, a wheel examination can be
carried out for each of the three axles simultaneously
and independently from one another. Besides, it is often
the case in a three axle vehicle that the wheels on the
intermediate and rear axles have the so-called double
wheel or double tire structure so as to be able to
support a heavy load. Even in such a case, with the
present system, any examination, such as measuring of an
inclination angle, can be carried out for each of the
wheels or tires on each of the axles individually.
With reference to Figs. 6 and 8, a particular
feature of the present three axle vehicle wheel examining
system according to the present invention will be
described below. In the wheel examining system shown in
Figs. 6 and 8, an interconnecting (or center positioning)
means of each of the front and rear wheel ~xAmining
sections 3f and 3r has a fixed or immovable center
- 35 -
CA 02242709 1998-06-08
position on the frame 2. This interconnecting or center
positioning means includes a pantagraph 5f or Sr which
operatively couples left-hand and right-hand wheel clamp
means, and the pantagraphs 5f or 5r has a stationary
center point 60f (not shown) or 60r on the frame 2.
Thus, a hypothetical straight line connecting these two
stationary center points 60f and ~Or defines the
reference center ~ine- CL of the present examining system.
Described more in detail, when the slider unit 2a is set
in its unlocked state, the center point 60r is set freely
movable along the reference center line CL; whereas, when
the slider unit 2a is set in its locked state, the center
point 60r is fixed in position on the frame 2.
With the above-described structure, when a
wheel is clamped by rollers lls and llu from both sides,
the center of the wheel is brought into alignment with
the center of the clamp means and at the same time the
left-hand and right-hand wheels are located symmetrically
with respect to the reference center line CL through the
pantagraphs 5r and 5f. In addition, the left-hand and
right-hand housings 8 are always located symmetrically
with respect to the reference center line CL through the
equalizer 4. Since a relative motion is possible between
the clamp means and the housing 8, the center of the
housing 8 is not necessarily in agreement with the center
of the clamp means.
- 36 -
CA 02242709 1998-06-08
On the other hand, the center position of
pantagraph Sm which serves as an interconnecting or
center positioning means of the intermediate wheel
examining section 3m is set on a slider unit 61. That
is, a pair of guide rails 62 is provided on the frame 2
extending in a direction perpendicular to the reference
center line CL. And, the slider unit 61 is slidably
mounted on these~gui~e rails 62. The pantagraph 5m and
the equalizer 4m have their center positions set on the
slider unit 61. Thus, the pantagraph 5m and the
equalizer 4m may shift in position either to the left or
to the right in the direction indicated by the arrow C
with respect to the reference center line CL by the
slider unit 61.
Accordingly, if the tread centers of the three
axles of a vehicle are not aligned on a common straight
line, the center line of its vehicle is defined by the
tread centers of the front and rear wheel axles only and
this center line is brought into alignment wit the
reference center line CL in the present examination
system. In this case, although the tread center of the
intermediate axle for the intermediate wheels becomes
shifted either to the left or to the right from the
reference center line CL, the amount of such a shift can
be advantageously absorbed by a relative movement between
the slider unit 61 and the rails 62. As a result, even
CA 02242709 1998-06-08
in the case of a three axle vehicle, the inclination
angle of each of its wheels can be measured at high
accuracy with respect to a predetermined reference line.
In addition, by measuring the amount of shift of the
slider unit 61 from the reference center line CL by a
meter 63, interaxle slip, i.e., the amount of discrepancy
among the tread centers can be measured.
In the ~mbodiment shown in Figs. 6 and 8, the
interconnecting or center positioning means of the
intermediate wheel examining section 3m is structured to
be movable in the transverse direction; however, it can
also be so structured that the interconnecting or center
positioning means of either or both of the front and rear
wheel examining sections 3f and 3r is shiftable to the
left and to the right. In addition, it may also be so
structured that the interconnecting or center positioning
means of all of the three wheel examining sections are
shiftable in position and can be locked in a desired
location selectively. Furthermore, the basic concept of
the present invention is equally applicable to a wheel
examining system for vehicles having four or more axles.
Now, a description will be had with respect to
another feature of the present invention, i.e., a novel
double encoder structure, which allows to measure the
inclination angle of each of the opposite side surfaces
of each wheel independently from each other and at the
CA 02242709 1998-06-08
same time. This feature is particularly useful for the
case for measuring the inclination angle of a wheel
having the so-called double wheel or double tire
structure.
In the first place, referring to Figs. 10 and
11, the detailed internal structure of a wheel examining
apparatus 3 for either of rear or' intermediate wheels,
which can be pro~rldea in either of the two axle vehicle
wheel examining system 1 shown in Figs. 1 and 2 and the
three axle vehicle wheel examining system 1 shown in
Figs. 6 through 9, is shown. If the front wheels of a
vehicle also have the so-called double wheel or double
tire structure, this wheel examining apparatus 3 can be
applied also to such front wheels.
As shown in Fig. 10, the wheel examining
apparatus 3 includes a box-shaped housing 8, which serves
as a base, and the housing 8 is mounted on rails 12
extending in the transverse direction perpendicular to
the reference center line CL to be slidably movable
either to the left or to the right, as described before.
The housing 8 is operatively coupled to one end of an
equalizer 4r through an arm 6. The housing 8 includes a
bottom plate 8b which is formed with an opening Bc
rectangular in cross section approximately at its center,
and a guide rail 32 is laid down along each side of the
opening 8c. On the guide rails 32 are slidably mounted a
- 39 -
CA 02242709 1998-06-08
pair of inner and outer roller supports 31u and 31z. The
inner roller support 31u generally has a "T" shape and
supports a pair of inner contact rollers llu rotatably on
top thereof. The inner roller support 31u has a
generally "T" shaped support section, which is rotatably
mounted on a slider unit which in turn is engaged with
the guide rails 32. The amount of relative rotating
angle between the~support section and the slider unit can
be detected by an inner angle detector 30ru which is
provided in association with the inner roller support
31u. Preferably, the angle detector 30ru is a rotary
encoder.
Similarly, the outer roller support 31s
supports a pair of outer contact rollers lls rotably at
its top. The outer roller support 31s has a generally
T-shaped support section which is rotatably mounted on a
slider unit which in turn is engaged with guide rails 32.
The amount of relative rotation between the support
section of the support 31s and the slider unit can be
detected by an outer angle detector 30rs which is
provided in association with the outer roller support
31s. Preferably, the angle detector 30rs is also a
rotary encoder. Thus, the inner and outer contact
rollers llu and lls are supported to be movable closer to
each other or separated away from each other and also
freely rotatable around a vertical axis.
- 40 -
CA 02242709 1998-06-08
The inner and outer roller supports 31u and 31s
are operatively coupled as being coupled to the opposite
ends of a clamping pantagraph 33. Moreover, a center
plate 34 is mounted at a mid-point of the clamping
pantagraph through a combination of rails and a slider
unit. Thus, independently of expanding and contracting
operation of the pantagraph 33, the c~nter plate 34 on
which rails are ~rovided is always maintained at the
center position of the pantagraph 33. The center plate
34 itself is slidably mounted on the guide rails 32 as a
slider unit so that it can move either to the left or to
the right. Accordingly, the center plate 34 is always
maintained at a center position between the inner and
outer contact rollers llu and lls, thereby defining the
position of a geometrical center of the roller clamp
mechanism. Integrally mounted on and extending under the
center plate 34 is a center column 35, which extends
downward to the exterior through an opening 8c formed in
the bottom plate 8b of the housing 8 and is operatively
coupled to the pantagraph 5r through an arm.
As best shown in Fig. 15, a cylinder 36a of a
clamping cylinder device is fixedly mounted on the center
column 35, and a rod 36b, which can move forwardly or
backwardly relative to the cylinder 36a, has a front end
coupled to the outer roller support 31s as best shown in
Fig. 14. Thus, by driving the clamp cylinder 36a, the
- 41 -
CA 02242709 1998-06-08
rod 36b may be caused to move in the forward direction or
in the backward direction, whereby the clamping
pantagraph 33 is expanded or contracted, and, as a
result, the inner and outer contact rollers llu and lls
are caused to move closer together or separated away from
each other. In this case, the center plate 34 is always
maintained midway between the inner and outer rollers llu
and lls, and the ~ef~-hand and right-hand center plates
34 are automatically maintained symmetrical in position
with respect to the reference center line CL through the
pantagraph 5r. Thus, when the inner and outer contact
rollers llu and lls are caused to move closer together by
operating the clamp cylinder 36a, the wheel Wr located
therebetween is clamped from both sides, whereby the
respective contact rollers are brought into contact with
the corresponding side surfaces of the wheel Wr. Under
this condition, the center position of the clamp
mechanism (i.e., position of the center plate 34) becomes
aligned with the center position of the clamped wheel Wr,
and, moreover, the left-hand and right-hand wheels Wr are
located symmetrical in location with respect to the
reference center line CL. That is, the tread center of
the left-hand and right-hand wheels Wr becomes located
right on the reference center line CL. In Figs. 12 and
13, the locations where the contact rollers are advanced
- 42 -
CA 02242709 1998-06-08
to their maximum are indicated by assigning a prime to
each of the reference numerals, such as llu' and lls'.
As described above, in the wheel examining
apparatus 3 for the rear or intermediate wheels, separate
angle detectors 30ru and 30rs are provided for the inner
and outer roller supports 31u and 31s, respectively. The
inner angle detector 30ru is provided to detect the
rotating angle around a vertical axis at the roller
support section of the inner roller support 31u, whereas
the outer angle detector 30rs is provided to detect the
rotating angle around a vertical axis at the roller
support section of the outer roller support 31s. Thus,
the inner and outer angle detectors 30ru and 30rs can
detect the rotating angles independently from each other.
The inner contact rollers llu are provided to be brought
into contact with the inner side surface of the wheel Wr,
whereas the outer contact rollers lls are provided to be
brought into contact with the outer side surface of the
wheel Wr. Thus, according to the present wheel examining
apparatus 3, the inclination angles of both of the side
surfaces of the wheel Wr can be measured independently
from each other.
The wheel examining apparatus 3 having such a
double encoder structure is particularly extremely useful
in the case where the wheel Wr to be examined has the
so-called double wheel or double tire structure. That
- 43 -
. ,.. ... . . . .. , .. , , ~.. ,, . . ~ .. ..
CA 02242709 1998-06-08
is, in such a case, instead of a simple single wheel, a
pair of sub-wheels or sub-tires are arranged side-by-side on
the same rotating axis in a fixed relationship such that
the two sub-wheels serve as a combined wheel assembly as
if it were a single wheel, and it is not uncommon that
these two sub-wheels or sub-tires are mounted together with
different inclination angles or alignment conditions. In
order to examine ~uc~ a misalignment condition in setting
of the inclination angle, it is necessary to make
measurements for each of the sub-wheels or sub-tires
individually; however, it was not possible to take such
measurements according to the prior art techniques.
In the present wheel examining apparatus 3
having the above-described double encoder structure,
since the inclination angles at the opposite inner and
outer side surfaces of the wheel Wr can be measured
independently from each other, it is possible to measure
the inclination angle of each of the sub-wheels or
sub-tires independently even with a wheel Wr having the
so-called double wheel or double tire structure. Thus,
it is possible to determine the amount of deviation of
each of the sub-wheels or sub-tires from a predetermined
inclination angle.
Now, a floating structure for supporting a
wheel movable in any direction in a predetermined plane
constructed in accordance with another feature of the
- 44 -
CA 02242709 1998-06-08
present invention will be described in detail below. A
preferred embodiment of this floating structure is
illustrated in Figs. 10, 11, and 17 through 20. First,
as shown in Figs. 10 and 11, four linear motion (LM)
guide units are mounted on the bottom plate 8b of the
housing 8 in a symmetrical arrangement. That is, each LM
guide unit includes a pair of lower guide rails 46
fixedly mounted on the bottom plate 8b, a lower slider
unit 45b slidably mounted on the lower guide rails 46, an
upper guide rail 45a fixedly mounted on the lower sliddr
unit 45b extending perpendicularly to the lower guide
rails 46, and an upper slider unit 44b slidably mounted
on the upper guide rail 45a. And, a cylindrically shaped
projection 44a projects upwardly from the top surface of
each of the upper slider units 44b. Thus, each of the
projections 44a may move in any direction translationally
over a predefined range relative to the bottom plate 8b.
On the other hand, a generally T-shaped support
roller table or assembly 40 for rotatably supporting a
pair of support rollers 15r is located inside the housing
8. The support roller assembly 40 is provided with four
circular holes 40a, each corresponding to each of the
projections 44a, and a rotary bearing 43 is mounted in
each of the circular holes 40a and fixedly attached to
the bottom portion of the support roller assembly 40 by
means of an attachment member 43a. An inner ring of each
- 45 -
., , ,.. ~ . ,
... , .. .. ... . ~ .
CA 02242709 1998-06-08
of the rotary bearings 43 is fitted onto a corresponding
one of the projections 44a to be integrated therewith.
Thus, the support roller assembly 40 as a whole is
provided to be movable translationally in any direction
over a predetermined range and also rotatable around a
vertical axis over a predetermined range. An example of
the locus of the support roller asse~bly 40 when it
executes a rotary motion relative to the housing 8 is
indicated by B in Fig. 17. In this manner, since the
support roller assembly 40 can execute a translation
motion and a rotational motion at the same time in any
direction relative to the housing 8, the support roller
assembly 40 is said to be set in a floating state. Thus,
in measuring the degree of inclination of the wheel
supported on the support rollers 15r, since the wheel is
maintained in a state in which it can move
translationally and rotate in any direction, the degree
of inclination of the wheel can be measured at high
accuracy.
In this manner, with the above-described
structure in which the support roller assembly 40 is
maintained in a floating state using four LM guide units,
even if a vehicle to be examined is relatively heavy, no
particular problems arise and each wheel can be set and
maintained in a floating state. Furthermore, with such a
four point support structure, force distribution can be
- 46 -
CA 02242709 1998-06-08
achieved so that a well-balanced floating state can be
obtained, which also contributes to carry out an
examination of a wheel at high accuracy. In the present
embodiment, use has been made of four LM guide units;
however, the present invention should not be limited only
to this particular number of LM guide units and it is
also possible to construct a floating' structure using
three or five or ~or~ LM guide units. Alternatively, use
may also be made of a plurality of rolling members, such
as rollers and balls, or a lubricant material, such as
grease, interposed between the bottom plate 8b of the
housing 8 and the support roller assembly 40 to provide a
floating structure between the support roller assembly 40
and the housing 8.
As described above, since the support roller
assembly 40 is maintained in a floating state relative to
the housing 8, an initial lock mechanism 10 is provided
for locking the support roller assembly 40 at its initial
position. That is, a cylinder device 10a is provided
with its one end pivotted to a side wall of the housing
8, and the cylinder device 10a houses therein a rod which
can be pushed out of and retracted into the cylinder
device 10a. The rod has a distal end to which the base
end of a first lock arm 10b is pivotally connected. On
the other hand, the cylinder of the cylinder device l0a
has its base end pivotally connected to the housing 8 and
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CA 02242709 1998-06-08
also to the base end of a second lock arm 10c. Moreover,
an interconnection lever 10d pivotally interconnecting
the center portions of the first and second lock arms lOb
and 10c is provided. A positioning roller 10e is
rotatably provided at the distal end of each of the first
and second lock arms 10b and 10c. On the other hand, a
"V" block member 41 is projectingly provided at the
center of each of~the front and back ends of the support
roller assembly 40 for receiving therein the
corresponding positioning roller 10e.
Thus, when the initial position lock device 10
is activated to set in its advanced position, the
positioning rollers lOe are cause to move closer together
and brought into engagement with the respective V block
members 41 and thus the support roller assembly 40 comes
to be locked into its initial position substantially at
the center of the housing 8. On the other hand, when the
initial position lock device 10 is activated to set in
its retracted position, the positioning rollers 10e are
moved to their retracted positions as shown in Figs. 10
and 11 and at the same time the support roller assembly
40 is set in its floating state, so that the support
roller assembly 40 can move translationally and
rotationally freely with a predetermined confines.
In the present wheel examining apparatus, the
wheel Wr supported on the support rollers 15r can be
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CA 02242709 1998-06-08
subjected to measurements of its inclination angle in a
stationary condition, or, alternatively, dynamic
measurements can also be taken while keeping the wheel Wr
in rotation. In the case of the dynamic mode of
operation, the support rollers 15r may be driven to
rotate, or, alternatively, the support rollers 15r may be
set in a freely rotating condition and~the wheel Wr may
be driven to rotate-by an engine of its vehicle. In this
case, due to the inclination angle of the wheel Wr, the
support rollers 15r receive an reaction force from the
wheel Wr, so that the support roller assembly 40 shifts
in the direction of this reaction force. In order to
absorb such a reaction force, there is also provided a
generally U-shaped first engaging projection 42 at the
front end of the support roller assembly 40 and a second
engaging projection 48a at a support 48 which is brought
into engagement with the first engaging projection 42
during operation. The support 48 is, for example,
fixedly mounted on an appropriate exterior member, such
as the frame 2. The second engaging projection 48a is
provided to be able to advance and retract, and advances
to be brought into engagement with the first engaging
projection 42 of the support roller assembly 40 when
necessary. For this reason, the front end wall of the
housing 8 is formed with an opening 8d, through which the
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CA 02242709 1998-06-08
second engaging projection 48a gains access to the
interior of the housing 8.
Next, referring in particular to Figs. 16
through 21, a roller lock device 50 for the support
rollers 15r will be described in detail below. The
support rollers l5r are set in a freely rotating
condition during operation, but they a~e set in a locked
condition when a -vehlcle to be examined is entering into
or exiting from the present examination system. For this
purpose, a roller lock device 50 is provided for each of
the support rollers 15r. Described more in detail, a
roller gear 54 is provided as fixedly attached to one end
of each of the support rollers 15r and an idle gear 55 is
also provided to be always in mesh with the roller gear
54. Also provided is a pair of lock gears 56 and 57
which are disposed on opposite sides of a mesh point
between the gears 54 and 55 and normally in mesh with the
roller gear 54. These lock gears 56 and 57 are rotatably
mounted on a pair of links 52 and 53, respectively, which
are pivotted around the rotating axis of the roller gear
54. In addition, a cylinder device comprised of a
cylinder 51a and a rod 51b is also provided as bridging
between the distal ends of the respective links 52 and
53. Thus, by bringing both of the lock gears 56 and 57
in mesh with both of the roller and idle gears 54 and 55
by activating the cylinder device, the support rollers
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CA 02242709 1998-06-08
15r can be set in its lock state (non-rotating state).
On the other hand, when these lock gears 56 and 57 are
set in the state shown in Fig. 21, the support rollers
15r are set in its freely rotating state.
As described above, in accordance with the
present invention, there is provided an improved wheel
examining system and apparatus, in whi~h each wheel can
be examined eitheT statically ~wheel not in rotation) or
dynamically (wheel in rotation) and various parameters of
wheel alignment, such as wheel inclination angles,
including toe angle and camber angles, can be measured at
high accuracy.
In accordance with the first feature of the
present invention, there is provided a wheel guide
apparatus including a plurality of guide rollers arranged
at different levels, and, thus, a vehicle to be examined
can be guided into a wheel examining apparatus smoothly
and stably and moreover since the vehicle is brought to a
desired examining position, its wheels may be located
symmetrically with respect to a predetermined reference
line automatically. In addition, even in the case where
the wheel has the so-called double wheel or double tire
structure, the wheel can be guided into a predetermined
examining site of a wheel examining apparatus speedily
and stably according to the present wheel guide
apparatus. Besides, when use is made of the present
CA 02242709 1998-06-08
wheel guide apparatus, the wheel examining apparatus
itself can be made smaller in size, and, in particular,
in its width.
In accordance with the second feature of the
present invention, an intermediate wheel examining
section is provided in addition to and inbetween the
front and rear wheel examining sections and all of these
three sections a~e independent from one another. Thus,
the alignment or inclination angle of each of the wheels
of a three-axle vehicle can be measured at high accuracy
and at the same time. In particular, since the
interconnecting means for interconnecting the left-hand
and right-hand wheel examining apparatuses in the
intermediate wheel examining section is located
downstream thereof with respect to the direction of
advancement of a vehicle to be examined and the
interconnecting means for interconnecting the left-hand
and right-hand wheel examining apparatuses in the rear
wheel examining section is located upstream thereof, the
wheel examining system for three-axle vehicles can be
made smaller in size. In addition, since the
intermediate wheel examining section is located in close
proximity of the rear wheel examining section, there is
no need to provide wheel guide apparatuses for the
intermediate wheel examining section.
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In accordance with the third feature of the
present invention, a double encoder structure including a
pair of inner and outer angle detectors associated with
the inner and outer clamp rollers, respectively, for
S clamping the opposite side surfaces of a wheel to be
examined is provided. With this structure, each of the
opposite side surfaces of a wheel càn be examined
independently, and,--thus, a more refined and high
accuracy examination can be carried out. When it is
desired to measure the overall inclination angle of a
wheel, the measured values from the inner and outer angle
detectors can be averaged out. In this manner, since the
opposite side surfaces of a wheel can be examined
independently, it is possible to find out the presence of
any irregularity at one of the two opposite surfaces, so
that any kind of irregularity other than those relating
to the inclination angle can also be found. In
particular, if the wheel to be examined has the so-called
double wheel or double tire structure comprised of a pair
of sub-wheels or sub-tires, each of the sub-wheels or
sub-tires can be examined independently. As a result,
the static and dynamic characteristic of a wheel having
such a double wheel structure can be determined extremely
at high accuracy.
In accordance with the fourth feature of the
present invention, there is provided an improved floating
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device for setting a wheel to be examined in a floating
state. With this floating structure, a stable and
reliable floating state can be established even for a
heavy load vehicle, such as trucks and buses. In
addition, in the present floating structure, since use is
made only of LM guide units and rotary bearings, the
structure is extremely simple and thus it can be
manufactured with~ease and at low cost.
While the above provides a full and complete
disclosure of the preferred embodiments of the present
invention, various modifications, alternate constructions
and equivalents may be employed without departing from
the true spirit and scope of the invention. Therefore,
the above description and illustration should not be
construed as limiting the scope of the invention, which
is defined by the appended claims.
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