Note: Descriptions are shown in the official language in which they were submitted.
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LOADWHEEL ALIGNMENT FIXTURE
TECHNICAL FIELD
The invention relates to test equipment and
in particular to a device for mounting on the chuck
assembly of a tire unifo.mity machine for checking the
parallelism and squareness of a loadwheel with respect
to a centerline spindle of the machine without removing
the chuck assembly. More particularly, the invention
relates to such a test fixture which self-aligns itself
automatically on the chuck assembly when clamped
therebetween and which supports measurement sensors for
engaging the outer surface and edges of the loadwheel.
BACKGROUND ART
_
Tire uniformity machines, also referred to as
tire uniformity optimi~ers (TU0) or tire uniformity
graders (TUG), have been developed and are used in the
tire lndustry for accurately measuring and grading the
radial and lateral force variations, conicity and ply
steer found within a cured tire. It also has the
ability to analy~e test data asld to correct for certain
nonuniformities in the tire. These machines consist of
a load carrying structure, precision rims and a
loadwheel. Top and bottom rims hold and rotate the
tire and the loadwheel, wllich is mounted on loadcells,
applies force to the inflated tire and detects force
variations in the tire. The loadcells provide signals
and test results to an ope.ator of the machine to
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indicate the condition of the tire and to take
corrective measures if possible. The readouts from the
loadcell provide very accurate measurements of tire
characteristics. The accuracy of these measurements is
S based upon the correct parallelism and squareness of
the machine spindle with the circumferential surface of
the loadwheel. After a certain number of operations it
is necessary to recheck the ?arallelism and squareness
of the loadwheel with respect to the machine spindle to
insure continued accuracy of the readouts. However,
monitoring minor adjustments is required periodically
to maintain this parallelism and squareness.
Heretofore, in order to measure these parameters, the
rims of the chuck assembly and spindle adaptor had to
be removed and an alignment adaptor shaft was placed on
the spindle shaft, and a single dial indicator was then
moved between top and bottom of the loadwheel surfaces
on the spindle shaft adaptor to obtain the alignment
readings However, a considerable amount of time and
work was required for the removal of the chuck rims and
placement of the spindle adaptor shaft on the spindle
shaft in order to take the measurement readings.
Another sensor then could be mounted on the spindle
adaptor shaft for checking the squareness of the
loadwheel with respect to the spindle shaft.
Since the dismantling o the machine, and in
particular, componen~s of the chuck assembly, is a
relatively time consuming and tedious operation, the
need exists for an improved device or fixture for
accurately measuring the parallelism and squareness of
a loadwheel circumferential surface with respect to the
`~spindle assembly of a tire uniformity machine without
requiring dismantling of the machine, yet without
sacrificing accuracy of the alignment readings.
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Various types of test apparatus and fixtures
have been developed for insuring the alignment of
various types of machines and equipment, examples of
which are shown in the following patents.
U.S. Patent No. 4,417,237 discloses an
apparatus and method for detecting and indicating
misalignment of vehicle wire spoke wheels wherein a
circuit is mounted at the bottom part of the wheel and
includes left and right misalignment sensors which
detect misalignment of a portion of the rim when the
rim is rotated.
U.S. Patent No. 2,613,447 discloses a testing
device for checking the alignment and the eccentricity
of automobile wheels, axles and brake drums. A sensor
wheel contacts the outer rim of the rotating member and
rotates about a pivot to indicate any eccentricity on
the member being tested.
U.S. Patent No. 3,128,561 discloses an
apparatus for measuring wheel alignment which uses a
pair of rods attached to conductive brushes. An
electrical meter is connected to the brushes and
indicates the potential differences between two
connections which are representative of the parallelism
between the wheels.
U.S. Patent No. 4,660,294 discloses a surface
ali~nment spparaCus having an upsCream turbine wheel
and a downstream turbine wheel positioned relative to a
stepped shaft. The measurements taken between ~aces of
the wheels are taken by extensometers which indicate
paralLelism of ~he two faces.
U.S. Patent No. 2,929,147 discloses a device
for checking dimensional variations or unevenness of
surface portions of an annular article. The checking
device includes contact members which are positioned to
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engage circumferentially spaced portions of the inner
braking surface of the liner at a predetermined
distance from each other. A gauge head is connected to
a power unit which is electrically connected to a meter
to detect variations in the article surfaces.
None of the above discussed prior art
patents, or other known prior art, is believed to show
or describe an alignment fixture which achieves these
advantages of the present invention which is described
in detail below.
DISCLOSURE OF THE INVENTION
Objectives of the invention include providing
a loadwheel alignment fixture having a cup/cone adaptor
block whieh is mounted between the upper and lower rims
of a chuck mechanism of a tire uniformity machine
without requiring removal of the rims or other portions
of the chuck mechanism, and which eliminates the
separate mounting of a spindle adaptor thereon as in
prior test proeedures.
Another objective is to provide such a
fixture whieh is of a relatively simple strueture,
readily formed o a hardened metal adaptor block formed
with a eonieal reeess whieh seats on the nose cone of
the lower rim of the ehuck assembly of a tire
uniformity maehine and has a eonieal-shaped upper
projection which seats into the nose cone sleeve of the
upper rim of the ehuck assembly, whereby an outer bar
parallel to the eenterline of the adaptor bloek will
align with the centerline of the spindle when the
adaptor bloek is elamped thereon by the ehuek assembly.
A further objective of the invention is to
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provide such a fixture in which various types of
sensors or gauges are mounted on the fixture for
engagement with the uncoated surfaces of the loadwheel
adjacent the edges thereof to provide simultaneous
signals indicating the parallelism of the loadwheel
force surface with respect to the spindle centerline
enabling adjustments to be made and their effect
immediately recognized; and in which another sensor can
be mounted on the fixture and brought into engagement
with the edge of the loadwheel to determine the
squareness of the loadwheel with respect to the spindle
centerline.
Still another objective is to provide such a
fixture wherein a slide bar can be moun~ed on the
sensor mounting bar for slidably mounting an LVDT or
similar transducer thereon for checking the profile of
the coated surface of the loadwheel. A further
objective is to provide such a fixture which can be
removably mounted on a lightweight aluminum sled for
moving the fixture into and out of position between the
spaced rims of the chuck mechanism facilitating the use
of the fixture.
Another objective of the invention is to
provide such an alignment fixture in which the adaptor
block has a flat surface ormed thereon parallel with
the outer suracè of the sensor attachment bar to allow
certification of the ixture at various times to insure
it is within the original manufacturing tolerances
prior to placing it in a tire uniormity machine for
use with the loadwheel.
A still further ob~ective of the invention is
to provide'such a fixture which can be formed
relatively inexpensively of a block of hardened metal,
precision ground to the desired size and configuration,
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which is mounted on a T-shaped mounting bar with the
outer arm component thereof functioning as the parallel
sensor mounting arm, and in which the fixture is free
of complicated and expensive moving parts subject to
maintenance and breakage.
These objectives and advantages are obtained
by the improved fixture of the invention, the general
nature of which may be stated as a fixture for checking
the alignment of a loadwheel of a tire uniformity
machine with respect to the centerline of the spindle
of said machine of the type having spaced first and
second chucks for rotatably mounting a tire to be
tested therebetween, in which the first chuck has a
nose cone sleeve formed with a conical-shaped recess
and the second chuck has a conical-shaped nose cone;
wherein said fixture includes an adaptor block having a
conical-shaped projection on one end of the block and a
conical-shaped recess formed in an opposite end of said
block, said projection being complementary to and
adapted to be inserted into the conical-shaped recess
of the first chuck with said conical-shaped recess
being complementary to and adapted to receive the nose
cone of the second chuck when said chucks are moved
towards each other to align a centerline o the adaptor
block with the centerline o the spindle; a support bar
mounted on the adaptor block and extending parallel
with the centerline o the adaptor block; and sensor
means mounted on the bar or en8aging the loadwheel to
measure the alignment of said loadwheel with respect to
the centerline of the spindle.
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BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the inventîon,
illustrative of the best mode i.n which applicant has
contem?lated ap?lying the principles, is set forth in
the following description and is shown in the drawings
and is particularly and distinctly pointèd out and set
forth in the appended claims.
FIG. 1 is a diagrammatic side view of a prior
art tire uniformity ~achine of the type with which the
improved alignment fixture of the invention is intended
for use;
FIG. 2 is an end view of the tire uniformity
machine of FIG. 1 showing a known loadwheel engaged
with a tire rotatably mounted in the chuck assembly
thereof;
FIG. 3 is an enlarged fragmentary elevational
view of the spindle assembly of the tire uniformity
machine of FIGS. 1 and 2, with portions of the chuck
assembly shown in section and with the improved
alignment fixture also shown partially in section,
cl.amped thereon and mounting a pair of sensors checking
the parallelism of a loadwheel;
FIG. 4 is a perspective view of ~he improved
alignment fixture mounted on a carrier sled;
FIG. 5 is an end elevational view of the
improved alignment fixture;
FIG. 6 is a fragmentary sectional view of the
adaptor block portion of the alignment fixture;
FIG. 7 is a diagrammatic view similar to FIG.
3 showing a sensor mounted on the alignment fixture
checking the squareness of the loadwheel;
FIG. 8 is a fragmentary sectional view taken
on line 8-8, FIG. 7;
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FIG. 9 is a fragmentary side elevational view
of the alignment fixture with a slide rod being mounted
thereon supporting another sensor for measuring the
circumferential profile of the loadwheel; and
FIG. 10 is an enlarged sectional view taken
on line 10-10, FIG. 9.
Similar numerals refer to similar parts
throughout the drawings.
BEST MODE FOR CARRYING OUT THE INVENTION
The loadwheel alignment fixture of the
invention is indicated generally at 1, and is shown
particularly in FIG. 4, mounted on a transport sled
indicated generally at 2. Fixture 1 is intended for
use with a tire uniormity machine indicated generally
at 3, and shown particularly in FIGS. 1 and 2. Machine
3 is of the type manufactured by Akron Standard
Division of Eagle-Picher Industries, Inc., and
identified as model 70. However, the alignment
fixture of the invention is adaptable for use with
other types o tire uniformity machines than the
particulsr one described below and shown in FIGS. 1 and
2.
Machine 3 is of a usual design and accurately
measures and grades the radial and lateral force
variations, conicity and ply steer found within a cured
pneumatic tire, indicated at 4. A tire handling system
moves a tire through the machine and usually consists
of two powered roller conveyors, indicated at 5 and 6,
for moving a tire into position between upper and lower
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chucks (FIG. 3) of the tire uniformity machine. At the
entrance of input conveyor 5, arms (not shown), are
used to center the tire on the conveyor and permit the
inlet of one tire at a time to the test section of the
machine. At the exit, or output conveyor 6, arms also
are used to hold the tire over a bead marker while the
tire is marked and graded before the tire is released
from the machine. The test section of machine 3
includes a main spindle assembly indicated generally at
9, which is shown in particular detail in FIG. 3.
Machine 3 includes a loadwheel 10 which is
freely rotatably mounted on appropriate bearings and a
shaft and has an outer surface 8, the majority of which
is coated with a friction material, indicated at 11 in
FIG. 3. The side edges 12 of loadwheel 10 preferably
are uncoated and provide two smooth strips which are
used to test the alignment of the loadwheel with
respect to spindle assembly 9 as described below.
Loadwheel 10 is moved horizontally into and out of
engagement with a tire 4 mounted in spindle assembly 9
as shown in FIG. 2, by positioning mechanisms 13 and 14
shown diagrammatically in FIG. 2. Positioning
mechanisms 13 and 14 which include a DC motor-driven
ball screw, advances a loadwheel carriage so that the
loadwheel engages the rotating tire and applies a
radial losd thereto. This load is operator selectable
and enables the characteristics o~ the tire to be
measured and displayed on appropriate equipment for
operator review. A plurality o~ load cells are
incorporated into the mounting mechanism for loadwheel
10 for performing and measuring various usual tests on
tire 4.
FIG. 3 discloses a usual spindle assembly 9
of the type with which the improved fixture 1 is
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intended for use. Spindle assembly 9 includes a main
shaft 16 rotatably supported in spaced bearings 17 and
18 and rotated by a drive gear assembly 19. An up?er
chuck indicated generally at 20, includes a spindle
adaptor 15 consisting of an integrally connected
nose-cone mounting plate 21 and a nose-cone sleeve 22.
Sleeve 22 is provided with a conical-shaped inner
recess 23. Plate 21 is securel.y mounted on shaft 16
for rotation with the shaft and has an upper rim 24
secured thereto by a plurality of bolts 25. A lower
chuck indicated generally at 26, includes a lower rim
27 which is attached by bolts 28 to a base 29. Base 29
is rotatably supported on a support shaft 31 by a
bearing assembly 32. Shaft 31 is mounted at its lower
end in a support base 33 and is vertically movable as
shown by arrow A to raise and lower chuck 26 with
respect to upper chuck 20. Lower chuck 27 further
includes a conical-shaped nose cone 36 which projects
upwardly through a central opening 34 formed in rim 27.
Nose cone 36 is conically shaped and is complementary
with nose cone sleeve recess 23 so that the two members
cooperate with each other for clamping a usual
pneumatic tire 4 therebetween when performing tests
thereon as shown in FI~S. 1 and 2. A plurality of air
passages 38 are ormed in nose cone 36 for admitting
and exhausting pressuri~ed air into and from a
pneumatic tire 4 when clamped between rims 24 and 27
durin8 testing.
The particular coniguration and cons.ruction
o spindle assembly 9 may vary, but most tire
uniformity machines will include upper and lower rims
24 and 27 with cooperating nose cone 36 and nose cone
sleeve 22. These are the main components of a tire
uniformity machine with which the improved alignment
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fixture cooperates for achieving the results of the
invention. The centerline of spindle assembly 9,
indicated generally at 35, extends through the aligned
centerlines of nose cone sleeve 22 and nose cone 36.
Fixture 1 is best illustrated in FIGS. 4, 5
and 6 and includes an adaptor block indicated generally
at 40, formed of a one-piece precision ground hardened
metal material. Block 40 has a generally cylindrical
base 41 formed with opposed parallel flat front and
rear surfaces 42 and 43 and parallel top and bottom
surfaces 44 and 45.
In accordance with one of the features of the
invention, a conical-shaped recess 46 is formed in base
41 and extends upwardly from bottom surface 45 (FIG. 6)
and is complementary in shape and size to nose cone 36.
Correspondingly, a conical-shaped pro.jection 47 is
formed integrally with base 41 and projects vertically
upwardly from top surface 44 and is complementary with
conical recess 23 of nose cone sleeve 22. A mounting
plate 49 is attached by bolts 48 to flat rear surface
43 of base 41 (FIG. 6) and has a mounting arm 50
attached thereto by welds 51. Mounting arm 50 extends
perpendicularly outwardly with respect to an imaginary
common centerline 52 of recess 46 and projection 47
tFIG. 6).
The other end o arm 50 is attached by welds
53 to a sensor support bar indicated generally at 54,
preferably at the mid-point of bar 54. Bar 54
preferably is square-shaped in cross-sectional
configuration and has a flat outer surface 55 and an
inner surface 56, with surface 55 being parallel with
flat front surface 42 of adaptor block 40. A plurality
of spaced horizontally extending holes 58 are formed in
bar 54 generally adjacent the upper and lower ends
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thereof. Holes 58 extend horizontally in parallel
alignment with mounting arm 50 and perpendicular to bar
surface 55. A pair of holes 59 are formed adjacent the
top and bottom ends of bar 54 and extend between end
faces 60 and 61 of the bar, perpendicular to the
direction of holes 58. The purpose and function of
holes 58 and 59 are discussed further below.
Checking the parallelism of loadwheel 10 with
fixture 1 is shown particularly in FIG. 3. Lower chuck
26 will be in a lowered position and sufficiently
spaced from upper chuck 20 permitting adaptor bloclc 40
to be placed on nose cone 36 by engagement of the nose
cone within conical-shaped recess 46 of block 40. The
appropriate machine controls are actuated raising lower
lS chuck 26 by vertical movement of shaft 31, bringing
conical-shaped projection 47 of block 40 into
engagement within complementary-shaped recess 23 of
nose cone sleeve 22. The engagement of the
complementary-shaped surfaces of the adaptor block with
the conical surfaces of the upper and lower chucks will
automatically align centerline 52 of adaptor block 40
with centerline 35 of spindle assembly 9. This
alignment of the two centerlines will automatically
align mounting arm 50 perpendicular to spindle
centerline 35, and correspondingly will align support
bar 54 parallel to spindle centerline 35 as shown in
FIG. 3.
A pair o sensors 64 are mounted in a pair of
the spaced holes 58 and have a sensing element 65 which
extends outwardly therefrom, which engages the uncoated
smooth surface strips 12 adjacent edges 66 of the
loadwheel. Sensors 64 preferably are digital
electronic indicators, such as of the type sold under
the trademark MAXUM by Federal Products Corporation of
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Providence, Rhode Island. If desired, sensors 64 can
be usual contact dial indicators having a contact
element which will actuate an indicating gauge on the
sensor. Manual rotation of the clamped chuck assembly
with fixture 1 therein, to position sensors 64
perpendicularly to the loadwheel surface, will provide
measurements and readings to indicate the parallelism
or non-parallelism of edge strips 12. Any misalignment
can be corrected by adjustment of the loadwheel
mounting mechanisms (not shown), which upon subsequent
rotation of the loadwheel will indicate if sufficient
correction has been made to insure that the face of the
loadwheel is parallel with spindle centerline 35.
After completion of the parallelism test, the
lower chuck is lowered and fixture 1 can be manually
removed from between the upper and lower chucks. To
facilitate the movement of fixture 1 into and from its
position between the spaced chucks, carrier sled 2 may
be utilized. Sled 2 preferably is formed of light
weight aluminum having a pair of spaced runners 68 and
a cross-member 69. A pair of support brackets 70
forming a V-shaped support, are mounted on each runner
68 and extend upwardly therefrom. A top support block
71 is mounted on each support bracket and is formed
with a recess 72.
To removably support fixture 1 on sled 2 a
pair of rods 74 may be threadably engaged in threaded
holes 75 (FIGS. 4 and 5) formed in bloclc base 41, the
outer ends of which are seated in support block recess
72. A channel 76 preferably is attached to
cross-member 69 for supporting the bottom end of
support bar 54 as shown in FIG. 4. Thus, fixture 1 is
loosely, movably supported on sled 2, whereby sled 2
can be placed on either the input or output conveyor
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for movement of adaptor block 40 between the spaced
chucks. Sled 2 either remains in position adjacent
spindle assembly 9 during the loadwheel test or can be
easily removed after block 40 is clamped between the
upper and lower chucks. Rod 74 may remain engaged in
base 41 or removed easily therefrom during the test.
Fixture 1 may also be used to check the
squareness of loadwheel 10 with respect to spindle
assembly 9 as shown diagrammatically in FIGS. 7 and 8.
Adaptor block 1 is clamped between the upper and lowe.
chucks in the same manner as described above. An
indicating gauge 78 is mounted on the end of a rod 79
which is fixed into a selected support bar hole 58 or
may be mounted on a slide rod 82 which is described
below, and extends outwardly therefrom. Bar 79 will
extend parallel with mounting arm 50 and
correspondingly perpendicular to spindle centerline 35.
Gauge 78 will have a sensing element 80 which is
brought into contact with peripheral edge 62 of
loadwheel 10. Fixture 1 is then rotated through a
predetermined angle indicated at B in FIG. 8 by
rotation of the clamped chuck assemblies, bringing
sensing element 80 to a second position on peripheral
edge 62. The cwo readings at the spaced edge locations
on the loadwheel will indicate the squareness of the
loadwheel with respec~ to spindLe assembly g. Similar
tests have been performed for determining the
squareness o the loadwheel, but by differenC and more
complicated prior art mechanisms than the use of
fixture 1.
Fixture 1 may also be used for measuring the
circumferential profile of coated surface 11 of
loadwheel 10 as shown in FIGS. 9 and 10. A slide rod
82 is mounted parallel to support bar 54 by a pair of
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mounting blocks 83 which are secured to bar 54 by bolts
84. Slide rod 82 is fixed in end holes 85 formed in
blocks 83 by set bolts 86. A clamp 88 is slideably
mounted on slide rod 82 and secured in a clamped fixed
position thereon by a threaded thumbwheel 89. A second
clamp 90 is mounted on and operated by thumbwheel 89
and secures a sensor 91 therein which has a sensing
element 92 at its outer end for engagement with surface
11 .
Sensor 91 preferably is a transducer, and in
particular an LVDT, and is connected by conductors 93
to appropriate recording mechanisms such as an
indicating graph. A profile of coated surface 11 is
obtained by a plurality of readings of surface 11 by
incremental adjustments of bracket 90 along slide rod
82, two positions which are shown in FIG. 9. At each
contact position the loadwheel will be rotated by a low
speed motor at least one cycle followed by the
subsequent repositioning of sensor 91 and rotation of
the loadwheel. For example, readings will be taken at
one inch lncrements along the circumference of coated
surface 11 which will provide an accurate proflle of
the coated surface to enable refurbishing of the
surace if necessary.
2S AccordLngly, improved fixture 1 provides a
device which automatically allgns with the centerline
of the spindle assembly of a usual tire uniformity
machine by the mutual engagement of the two
complementary-shaped, preferably conical surfaces, with
two conical-shaped recesses, which aligns a support bar
having one or more sensors mounted thereon for
measuring both the parallelism and squareness of the
loadwheel with respect to the centerline of the spindle
and, in addition, enables the profile of the coated
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loadwheel surface to be determined. Also, a carrier
sled is provided to facilitate the placement and
removal of the adaptor block between the spaced chucks
of the spindle assembly, and in which the tests are
performed without removing either of the tire mounting
rims or spindle components as heretofore required with
prior art alignment tests.
Outer flat face 42 of adaptor block 40
provides an easy method of certifying the align~ent of
the centerline of adaptor block 40 with support bar 54
to insure that the fixture is pro?erly aligned when it
is mounted on a spindle assembly for performing tests
on the associated loadwheel. The precision grinding o~
surface 42 parallel with surface 43 and ultimately with
the outer surface 55 of support bar 54, enables block
surface 42 to be placed on a planar table surface and
appropriate measurements performed on bar surface 55 to
certify the alignment of support bar 54 with centerline
52 of block 40.
Accordingly, the improved loadwheel alignment
fixture is simplified, provides an effective, safe,
inexpensive, and efficient device which achieves all
the enumerated objectives, provides or eliminating
difficulties encountered with prior devices, and solves
problems and obtains new results in the art.
In the foregoing description, certain terms
have been used or brevity, clearness and
understanding; but no unnecessary limitations are to be
implied therefrom beyond the requirements of ehe prior
art, because such terms are used or descriptive
purposes and are intended to be broadly construed.
Moreover, the description and illustration of
the invention is by way of example, and the scope of
the invention is not limited to the exact details shown
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or described.
Having now described the features,
discoveries and principles of the invention, the manner
in which the improved loadwheel alignment fixture is
constructed and used, the characteristics of the
construction, and the advantageous, new and useful
results obtained; the new and useful structures,
devices, elements, arrangements, parts, and
combinations, are set forth in the appended claims.
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