U.S. patent application number 10/315344 was filed with the patent office on 2004-06-10 for tire buffing apparatus.
This patent application is currently assigned to Bandag Incorporated. Invention is credited to Gubser, Kelly Darin, Mory, Steven W., Turner, Andy Wayne.
Application Number | 20040108076 10/315344 |
Document ID | / |
Family ID | 32325897 |
Filed Date | 2004-06-10 |
United States Patent
Application |
20040108076 |
Kind Code |
A1 |
Mory, Steven W. ; et
al. |
June 10, 2004 |
TIRE BUFFING APPARATUS
Abstract
A tire buffer for buffing a tire casing as part of a retread
operation can include a rasp pedestal having a rasp head and a
texturing device. A moving assembly can be connected to the rasp
pedestal for selectively moving the rasp pedestal along a pair of
perpendicular axes. The rasp pedestal can rotate about a vertical
axis. A tire hub assembly can be included for rotating the tire
casing. The tire buffer can be operated at an operator station by
interfacing with a control unit. The tire buffer can automatically
buff a tire casing to achieve a predetermined tire casing profile
and impart a texture thereto. The tire buffer includes a tire
location mechanism and a tire measurement mechanism mounted to the
rasp pedestal. The control unit can monitor an operating parameter
of the rasp pedestal or the tire hub assembly during the buffing
sequence, compare the actual value of the operating parameter to a
predetermined target value of the parameter, and adjust an
operating characteristic of the rasp pedestal, the tire hub
assembly, or both such that the actual value of the operating
parameter is urged toward the calculated target value of the
operating parameter.
Inventors: |
Mory, Steven W.; (Muscatine,
IA) ; Gubser, Kelly Darin; (Muscatine, IA) ;
Turner, Andy Wayne; (Iowa City, IA) |
Correspondence
Address: |
LEYDIG VOIT & MAYER, LTD
TWO PRUDENTIAL PLAZA, SUITE 4900
180 NORTH STETSON AVENUE
CHICAGO
IL
60601-6780
US
|
Assignee: |
Bandag Incorporated
Muscatine
IA
|
Family ID: |
32325897 |
Appl. No.: |
10/315344 |
Filed: |
December 9, 2002 |
Current U.S.
Class: |
157/13 |
Current CPC
Class: |
B29D 2030/541 20130101;
B24B 5/366 20130101; B29L 2030/00 20130101; B29D 2030/546 20130101;
B29K 2021/00 20130101; B29D 30/54 20130101 |
Class at
Publication: |
157/013 |
International
Class: |
B29D 030/68 |
Claims
What is claimed is:
1. A tire buffing apparatus for buffing a tire casing, the tire
buffing apparatus comprising: a base; a rasp pedestal, the rasp
pedestal including a rasp head and a texturing device; a moving
assembly mounted to the base assembly, the moving assembly
connected to the rasp pedestal for selectively moving the rasp
pedestal along a pair of perpendicular axes, the rasp pedestal
pivotable about a vertical axis with respect to the moving
assembly; a tire hub assembly for supporting and rotating the tire
casing, the tire hub assembly mounted to the base at a
predetermined location; a control unit operatively arranged with
the rasp pedestal, the moving assembly, and the tire hub assembly
for selective operation thereof, the control unit capable of
monitoring the position of the rasp pedestal with respect to the
tire hub assembly; wherein the rasp pedestal is movable into
engagement with a tire casing mounted to the tire hub assembly such
that the rasp head can contact the tire casing to buff the tire
casing to impart a predetermined tire casing profile and such that
the texturing device can contact the tire casing to impart a
predetermined texture to at least a portion of the tire casing.
2. The tire buffing apparatus according to claim 1, further
comprising: an operator station, the operator station extending
from the base assembly, the operator station having a touch screen
electrically connected to the control unit, the touch screen
comprising an operator interface for the control unit.
3. The tire buffing apparatus according to claim 2, wherein the
touch screen is adjustably mounted to the base.
4. The tire buffing apparatus according to claim 1, wherein the
rasp pedestal includes a conduit for connection to a collection
system.
5. The tire buffing apparatus according to claim 1, wherein the
moving assembly includes a base runner, an X table, and a Y table,
the base runner mounted to the base, the X table movably mounted to
the base runner such that the X table is movable along an X axis,
the Y table movably mounted to the X table such that the Y table is
movable along a Y axis, the Y axis being perpendicular to the X
axis.
6. A tire buffing apparatus for buffing a tire casing, the tire
buffing apparatus comprising: a rasp pedestal, the rasp pedestal
including a rasp head and a texturing device; a moving assembly
connected to the rasp pedestal for selectively moving the rasp
pedestal along a pair of perpendicular axes; a tire hub assembly
for supporting and rotating the tire casing; wherein the moving
assembly is operable to move the rasp pedestal into engagement with
a tire casing mounted to the tire hub assembly such that the rasp
head can contact the tire casing to buff the tire casing to impart
a predetermined tire casing profile and such that the texturing
device can contact the tire casing to impart a predetermined
texture to at least a portion of the tire casing.
7. The tire buffing apparatus according to claim 6, wherein the
rasp pedestal includes a support assembly and a rasp head assembly,
the rasp head assembly housing the rasp head and the texturing
device.
8. The tire buffing apparatus according to claim 6, wherein the
texturing device comprises a wire brush.
9. The tire buffing apparatus according to claim 6, wherein the
rasp pedestal includes a rasp drive motor operably arranged with a
rasp shaft, the rasp head and the texturing device mounted to the
rasp shaft for rotation thereof.
10. The tire buffing apparatus according to claim 9, wherein the
rasp pedestal includes a detent cylinder operably arranged with the
rasp shaft to selectively prevent the shaft from rotating.
11. The tire buffing apparatus according to claim 6, wherein the
rasp pedestal includes a plurality of feed lines which are arranged
to selectively dispense fluid therefrom onto the rasp head.
12. The tire buffing apparatus according to claim 6, wherein the
rasp head is mounted to a rasp shaft, the rasp pedestal includes a
tire measurement mechanism arranged with the rasp head to detect
movement thereof, the tire measurement mechanism arranged with the
control unit to signal the control unit upon sensing movement of
the rasp head, the control unit configured to monitor the location
of the rasp pedestal with respect to the tire hub assembly.
13. The tire buffing apparatus according to claim 6, wherein the
rasp pedestal includes a tire sensor, the tire sensor arranged on
the pedestal such that it can detect a tire casing mounted to the
tire hub assembly when the rasp pedestal is within a predetermined
distance of the tire hub assembly.
14. The tire buffing apparatus according to claim 6, wherein the
rasp pedestal includes a rasp shaft, a support plate, a rasp drive
motor, and a belt, the rasp head connected to the rasp shaft, the
drive motor pivotally connected to the support plate, the drive
motor operably arranged with the rasp shaft via the belt, the drive
motor pivotal with respect to the support plate to adjust the
tension of the belt.
15. A tire buffing apparatus for buffing a tire casing, the tire
buffing apparatus comprising: a tire hub assembly for supporting
and rotating the tire casing; a rasp pedestal, the rasp pedestal
including a rasp shaft, a rasp head mounted thereto, and a tire
measurement mechanism arranged with the rasp head to detect
movement thereof, the rasp pedestal movable with respect to the
tire hub assembly; and a control unit, the control unit configured
to monitor the location of the rasp pedestal with respect to the
tire hub assembly, and the tire measurement mechanism arranged with
the control unit to signal the control unit upon sensing movement
of the rasp head in response to the rasp head engaging the tire
casing rotating on the tire hub assembly, whereby the control unit
can determine the size of the tire casing mounted to the tire hub
assembly.
16. The tire buffing apparatus according to claim 6, wherein the
tire measurement mechanism includes a sprocket mounted to the rasp
shaft and a proximity sensor arranged with the sprocket to detect
movement thereof, the proximity sensor electrically connected to
the control unit.
17. A tire buffing apparatus for buffing a tire casing, the tire
buffing apparatus comprising: a tire hub assembly for supporting
and rotating the tire casing; a rasp pedestal, the rasp pedestal
including a rotatable texturing device, the rasp pedestal movable
with respect to the tire hub assembly; and a control unit, the
control unit configured to monitor the location of the rasp
pedestal with respect to the tire hub assembly, and the control
unit operable to move the rasp pedestal with respect to the tire
hub assembly such that the texturing device can contact the tire
casing to impart a predetermined texture to at least a portion of
the tire casing mounted to the tire hub assembly.
18. The tire buffing apparatus according to claim 17, wherein the
texturing device comprises a wire brush.
19. The tire buffing apparatus according to claim 17, wherein the
rasp pedestal includes a drive motor for rotating the texturing
device, a current sensor is associated with the drive motor for
sensing the current draw of the drive motor, the current sensor
being electrically connected to the control unit for conveying the
value of the current draw to the control unit, the control unit
capable of moving the rasp pedestal toward the tire casing mounted
to the tire hub assembly with the texturing device rotating until
the current sensor signals the control unit that the current draw
of the drive motor reaches a predetermined value.
20. A tire buffing apparatus for buffing a tire casing, the tire
buffing apparatus comprising: a tire hub assembly for supporting
and rotating the tire casing; a rasp pedestal, the rasp pedestal
including a rotatable rasp head, the rasp pedestal movable with
respect to the tire hub assembly; and a control unit, the control
unit configured to monitor the location of the rasp pedestal with
respect to the tire hub assembly, and the control unit operable to
monitor an operating parameter of one of the rasp pedestal and the
tire hub assembly while buffing the tire casing mounted to the tire
hub assembly, compare the actual value of the operating parameter
to a predetermined target value of the parameter, and adjust an
operating characteristic of at least one of the rasp pedestal and
the tire hub assembly such that the actual value of the operating
parameter is urged toward the target value of the operating
parameter.
21. The tire buffing apparatus according to claim 20, wherein the
rasp pedestal includes a rasp drive motor for rotating the rasp
head, the operating parameter comprises the current draw of a rasp
drive motor, and the operating characteristic comprises the feed
rate of the rasp pedestal as the pedestal traverses the tire casing
mounted to the tire hub assembly to buff the casing.
22. A method for buffing a tire casing comprising: mounting the
tire casing to a tire hub assembly for rotating the tire casing;
rotating the tire casing; moving a rasp pedestal relative to the
tire hub assembly toward the tire hub assembly, the rasp pedestal
including a rasp head; monitoring the position of the rasp
pedestal; detecting when the rasp head engages the tire casing by a
measurement mechanism mounted to the rasp pedestal; and determining
the size of the tire casing by comparing the location of the tire
hub assembly to the location of the rasp pedestal when the rasp
head engages the tire casing.
23. The method according to claim 22, wherein the rasp pedestal
includes a rotatable rasp shaft to which the rasp head is mounted,
the tire measurement mechanism includes a sprocket mounted to the
rasp shaft and a proximity sensor arranged with the sprocket to
detect movement thereof.
24. The method according to claim 22, further comprising: detecting
the tire casing mounted to the tire hub assembly when the rasp
pedestal is within a predetermined distance of the tire hub
assembly.
25. The method according to claim 24, wherein the tire casing
detecting step is performed by a tire sensor, the tire sensor
arranged on the pedestal.
26. The method according to claim 25, further comprising: advancing
the rasp pedestal toward the tire hub assembly at a first rate of
speed until the tire sensor detects that the rasp pedestal is
within a predetermined distance of the tire casing whereupon the
rasp pedestal is advanced toward the tire hub assembly at a second
rate of speed, the second rate less than the first rate.
27. A method for buffing a tire casing comprising: mounting the
tire casing to a tire hub assembly for rotating the tire casing;
rotating the tire casing; moving a rasp pedestal relative to the
tire hub assembly toward the tire hub assembly, the rasp pedestal
including a rasp head; engaging the rasp head with the tire casing;
moving the rasp head along a predetermined buffing path to define a
predetermined tire casing profile, the buffing path including a
plurality of passes wherein the rasp head is moved across the width
of the tire casing; and monitoring an operating parameter of one of
the rasp pedestal and the tire hub assembly while moving the rasp
head along the buffing path; comparing an actual value of the
operating parameter to a predetermined target value of the
parameter; and adjusting an operating characteristic of at least
one of the rasp pedestal and the tire hub assembly such that the
actual value of the operating parameter is urged toward the target
value of the operating parameter.
28. The method according to claim 27, wherein the rasp pedestal
includes a rasp drive motor for rotating the rasp head, the
operating parameter comprises the current draw of a rasp drive
motor, and the operating characteristic comprises the feed rate of
the rasp pedestal as the pedestal traverses the tire casing mounted
to the tire hub assembly to buff the casing.
29. The method according to claim 27, further comprising: moving
the rasp pedestal with respect to the tire casing mounted to the
tire hub assembly to respectively engage a texturing device mounted
to the rasp pedestal with a pair of shoulders of the tire casing
for a predetermined time to impart a predetermined texture upon the
shoulders.
30. The method according to claim 29, further comprising: rotating
the texturing device by a rasp drive motor mounted to the rasp
pedestal; monitoring the current draw of the rasp drive motor;
moving the rasp pedestal toward the tire casing with the texturing
device engaged with the tire casing until the current draw of the
rasp drive motor reaches a predetermined value.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to devices and
methods for retreading tires, and more particularly to devices and
methods for buffing a tire casing to remove worn tread.
BACKGROUND OF THE INVENTION
[0002] In general, devices for removing the tread of worn tires,
often called buffers or raspers, are well known. Tire buffing is
part of the tire retreading operation. The method of tire
retreading described herein is commonly referred to as
"cold-process retreading."
[0003] Typically the tire casing selected for retreading is buffed
to remove excess rubber to provide a substantially evenly-textured
crown for receiving a pre-cured tread strip and to provide a
predetermined tire casing profile. Tire casings usually include a
belt package (a package of steel belts or cables) underlying the
road-engaging surface (e.g., the original tread) of the tire. Prior
to retreading, the casing must be buffed, generally to a
predetermined characteristic crown radius corresponding to the
upper contour of the belt package. The casing is buffed to leave
only a predetermined thickness, e.g., {fraction (3/32)} of an inch,
of material remaining over the top belt. The shoulder of the casing
is also buffed (trimmed) to eliminate or reduce voids or patterns
in the shoulder created by the original tread, and to provide,
typically, a relatively straight profile between the casing side
walls and the crown. A worn casing from each of the various models
and sizes of new tires has a characteristic tire casing profile of
a particular crown width, crown buffing radius and shoulder trim
angle which must be created as an initial step in the buffing
process.
[0004] After being buffed, the tire casing may then be examined for
injuries, which are skived and filled with a repair gum. After
completion of the skiving process, the buffed surface may be
sprayed with tire cement that provides a tacky surface for
application of a suitable layer of bonding material, such as
cushion gum. Conventionally, the cushion gum is a layer of uncured
rubber material, which optionally includes a low temperature
vulcanizing agent and accelerator. The cushion gum can be placed
over the crown. In some retreading operations, the spray cement can
be omitted.
[0005] Then a cured tread strip, typically of a width corresponding
to the width of the crown of the casing is cut to the length
corresponding to the casing circumference and is disposed over the
casing crown. Alternatively, continuous replacement treads in the
shape of a ring (i.e., ring treads) have also been used to retread
the buffed casing. A roller pressing process, commonly referred to
as stitching, is next performed on the assembly to force air from
between the tread strip and casing.
[0006] After stitching the tire assembly, which comprises the tire
casing, the cushion gum and the tread, the assembly can be placed
within a flexible rubber envelope. An airtight seal can be created
between the envelope and the bead of the tire casing. The entire
envelope, with the tire assembly disposed therein, can be placed
within a curing chamber and subjected to elevated pressure and
temperature for a predetermined period of time. The combination of
exposure to elevated pressure and temperature for a duration of
time binds the cushion gum to both the tire casing and the new tire
tread.
[0007] The tire buffing step of the retreading process can require
the face of the casing, which receives the replacement tire tread,
to be buffed to a predetermined crown radius within a relatively
small tolerance. In addition, with the advent of new replacement
tire tread designs, such as the contoured replacement tread
disclosed in U.S. Pat. No. 5,277,727, issued Jan. 11, 1994, it can
also be necessary to ensure that the shoulder radius is also buffed
precisely to a predetermined arc, or radius.
[0008] In present retreading processes, it is important that the
surface of the tire casing be carefully buffed about the shoulder
areas of the tire to ensure that the tread layer width is
approximately the same as the buffed surface of the casing. If the
shoulder areas are not sufficiently buffed and trimmed, the tread
edges may come loose and/or the cushion gum extending beyond the
tread edges will not bond to the casing shoulder. Such problems can
reduce the longevity of the retreaded tire and adversely impact the
appearance of the retreaded tire.
[0009] The tire casing is buffed to remove tread material and to
achieve a desired surface texture. Typically, it is desired for the
crown and the shoulders of the tire casing to have different
textures. The surface texture can be measured on a visual scale
propounded by the Rubber Manufacturer's Association (RMA) with a
numerical value between 1 and 6 with 1 being the finest and 6 being
the roughest texture. Typically, it is desired for the crown of the
tire casing to have a RMA number of between 3 and 4 and for the
shoulder to have an RMA number of about 2. The shoulders of the
tire casing typically are subjected to the largest stresses
encountered by the tire during service. The finer texture on the
shoulders promotes better adhesion of the tire tread to the casing
at these high stresses. If the shoulders received too much
texturing, crack propagation in these areas is more likely. In
instances where the shoulder receives too little texturing, the
bond between the tire casing and the tread is poorer.
[0010] The current state of the art in tire casing buffing allows
for a multiplicity of tread removal passes, substantially in a
sideways, pass after pass method. Known manual devices which
require an operator to physically direct the buffing machine's
removal direction and speed produce time periods between tread
removal passes where the rate of tread rubber removal is less than
optimum. Known automated devices in which the buffing machine's
removal direction and speed is predetermined by an operator also
produce time periods of less than optimum tread rubber removal.
[0011] Thus, there exists a need for a tire buffing machine which
is easy to use and which improves tire buffing efficiency.
SUMMARY OF THE INVENTION
[0012] The present invention provides a tire buffing apparatus for
buffing a tire casing as part of a retread operation. The tire
buffer can include a rasp pedestal having a rasp head and a
texturing device. A moving assembly can be connected to the rasp
pedestal for selectively moving the rasp pedestal along a pair of
perpendicular axes. The rasp pedestal can rotate about a vertical
axis. A tire hub assembly can be included for rotating the tire
casing. The tire buffer can be operated at an operator station by
interfacing with a control unit. The tire buffer can automatically
buff a tire casing to achieve a predetermined tire casing profile
and impart a texture thereto. The tire buffer can include a tire
location mechanism and a tire measurement mechanism mounted to the
rasp pedestal.
[0013] The present invention can improve the overall efficiency of
tread rubber removal during the buffing step of a tire retreading
process. The control unit can monitor an operating parameter of the
rasp pedestal or the tire hub assembly during the buffing sequence,
such as the current draw of the rasp drive motor, for example,
compare the actual value of the operating parameter to a
predetermined target value of the parameter, and adjust an
operating characteristic of the rasp pedestal, the tire hub
assembly, or both, such as the traverse speed of the rasp pedestal
with respect to the tire casing as it makes a pass, for example,
such that the actual value of the operating parameter is urged
toward the calculated target value of the operating parameter.
[0014] In one aspect of the invention, the main tread cutter of the
tire buffer can be configured such that the cutter speed, i.e., the
traverse speed of the cutter across the width of the tire casing,
and the cutter feed, i.e., the depth of cut of the tread cutter,
can both be adjustable. In one embodiment, an operator can select a
feed rate for the cutter before the buffing operation begins.
During the buffing cycle, the tire buffer can monitor the current
draw on the motor operating the cutter and compare the actual
current draw against a predetermined desired current draw. The
cutter speed can be varied in response to any measured difference
between the actual current draw and the predetermined current draw,
with the speed increasing to increase the actual current draw and
with the speed decreasing to decrease the actual current draw.
[0015] In a tire measurement operation, the rasp head can be moved
toward the tire casing with the blades of the rasp being stationary
and the tire casing, mounted to the tire chuck of the tire hub
assembly, rotating. The rasp can be moved with respect to the tire
hub assembly via the moving assembly. The rasp can be moved with
respect to the tire hub assembly such that the rasp contacts the
tire casing. Upon contacting the tire casing, the blades of the
rasp head rotate in response to the rotation of the tire casing. A
sensor can sense when the rasp blades start spinning and signal
such occurrence to a control unit, thereby indicating the size of
the tire casing.
[0016] The tire buffer includes an automated buffing operation. The
main rasp, upon completion of the buffing step, can be positioned
with respect to the tire casing to trim the shoulders thereof. The
desired shoulder geometry can vary depending on the tire tread
being used in the retreading process.
[0017] In another aspect of the invention, the tire buffer includes
an automated shoulder texturing feature carried out by a texturing
device, such as a wire brush, for example, mounted on the same
spindle as the main tread cutter, the rasp head. By providing a
tire buffer which has automated buffing and shoulder texturing
features, the output of buffed tire casings from said machine is
improved by facilitating the buffing process to deliver a more
consistent texture profile across the tire casing and from tire
casing to tire casing.
[0018] In the automated shoulder texturing operation, the texturing
device is moved with respect to the tire casing with the texturing
device being aligned with one of the shoulders. The texturing
device is moved toward the tire casing with the texturing device
rotating. A control unit monitors the current required to operate
the texturing device to gauge the degree of contacting force
between the shoulder and the texturing device. The texturing device
is moved into the tire casing until the motor current reaches a
predetermined level, at which point the texturing device stops
moving closer to the tire casing. The texturing device is operated
at this position for a predetermined amount of time to provide the
desired shoulder texture. The rasp pedestal is moved with respect
to the tire casing such that the texturing device is aligned with
the other shoulder, and the same process is repeated for that
shoulder.
[0019] The features of the present invention will become apparent
to one of ordinary skill in the art upon reading the detailed
description, in conjunction with the accompanying drawings,
provided herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a top plan view of a tire buffer according to the
present invention.
[0021] FIG. 2 is a front elevational view of the tire buffer of
FIG. 1.
[0022] FIG. 3 is a side elevational view of the tire buffer of FIG.
1.
[0023] FIG. 4 is a side elevational view of the tire buffer of FIG.
1 as in FIG. 3, with a tire chuck removed for illustrative
purposes.
[0024] FIG. 5 is a top plan view of a base assembly and a rasp
pedestal moving assembly of the tire buffer of FIG. 1.
[0025] FIG. 6 is a side elevational view of a rasp pedestal of the
tire buffer of FIG. 1 with a pedestal cover and a belt guard
removed for illustrative purposes.
[0026] FIG. 7 is a top plan view of the rasp pedestal of FIG.
6.
[0027] FIG. 8 is a rear elevational view of the rasp pedestal of
FIG. 6.
[0028] FIG. 9 is a front elevational view of the rasp pedestal of
FIG. 6, partially cut away, shown with a rotator assembly mounted
thereto.
[0029] FIG. 10 is an enlarged detail view taken from FIG. 9.
[0030] FIG. 11 is a second side elevational view, partially in
section, of a buffing assembly of a rasp head assembly of the rasp
pedestal of FIG. 6.
[0031] FIG. 12 is a fragmentary, first side elevational view,
partially in section, of a rasp shaft and a texturing device of the
buffing assembly of FIG. 11.
[0032] FIG. 13 is a side elevational view of the rasp head assembly
of the rasp pedestal of FIG. 6.
[0033] FIG. 14 is a rear elevational view of the rasp head assembly
of FIG. 13.
[0034] FIG. 15 is a top plan view of the rasp head assembly of FIG.
13.
[0035] FIG. 16 is a rear elevational view of the rasp head assembly
of FIG. 13.
[0036] FIG. 17 is a partial, fragmentary second side elevational
view of the rasp head assembly of FIG. 13 as viewed from line 17-17
in FIG. 14.
[0037] FIG. 18 is a partial, cross-sectional view taken along line
18-18 in FIG. 13.
[0038] FIG. 19 is a front elevational view of a rasp of the buffing
assembly of FIG. 18.
[0039] FIG. 20 is cross-sectional view taken along line 20-20 in
FIG. 19.
[0040] FIG. 21 is a front elevational view of a wire brush of the
buffing assembly of FIG. 18.
[0041] FIG. 22 is an end elevational view, partially in section, of
the wire brush of FIG. 21.
[0042] FIG. 23 is a schematic view of a touch screen display.
[0043] FIG. 24 is a schematic view of a second touch screen
display.
[0044] FIG. 25 is a cross-sectional view of a tire casing
illustrating a tire casing profile which can be defined by the tire
buffer of the present invention and of a replacement tread for
application to the tire casing.
[0045] FIG. 26 is a cross-sectional view of another embodiment of a
tire casing illustrating a tire casing profile which can be defined
by the tire buffer of the present invention and of a replacement
tread for application to the tire casing.
[0046] FIG. 27 is a top plan view of the tire buffer of FIG. 1 with
a tire casing mounted to a hub assembly thereof and the rasp
pedestal of the tire buffer in a home position.
[0047] FIG. 28 is a top plan view of the tire buffer of FIG. 1 and
the tire casing as in FIG. 27 with the rasp pedestal in a
measurement position to performing a tire measurement
operation.
[0048] FIG. 29 is a block diagrammatic view of an adjusting
sequence for efficiently removing tire material during a buffing
operation.
[0049] FIG. 30 is a top plan view of the tire buffer of FIG. 1 and
the tire casing as in FIG. 27 with the tire buffer performing a
shoulder trimming operation.
[0050] FIG. 31 is a top plan view of the tire buffer of FIG. 1 and
the tire casing as in FIG. 27 with the tire buffer performing a
shoulder texturing operation.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0051] In accordance with the teachings of the present invention,
there is provided a tire buffing apparatus for buffing a tire
casing as part of a retread operation. The tire buffing apparatus
can include a base assembly, a rasp pedestal, a moving assembly, a
tire hub assembly, an operator station associated with a control
unit, an electrical enclosure, and a pneumatic enclosure. The rasp
pedestal can include a rasp head and a texturing device mounted to
a single shaft for rotation thereabout. The rasp pedestal can
rotate about a vertical axis. The moving assembly can be mounted to
the base assembly and connected to the rasp pedestal for
selectively moving the rasp pedestal along a pair of perpendicular
horizontal X and Y axes. The tire hub assembly can be included for
rotating the tire casing. The tire buffer can be operated at the
operator station by interfacing with the control unit, which can be
housed in the electrical enclosure. The tire buffer can include a
tire location mechanism mounted to the rasp pedestal for detecting
a tire casing mounted to the tire hub assembly when the rasp
pedestal is within a predetermined distance of the tire casing. A
tire measurement mechanism can be mounted to the pedestal for
measuring the size of the tire casing mounted to the hub
assembly.
[0052] The tire buffer can automatically buff a tire casing to
achieve a predetermined tire casing profile and impart a texture
thereto. The control unit can be associated with a current sensor
which senses the current draw of a rasp drive motor for rotating
the rasp head and the texturing device. During the buffing
sequence, the control unit can compare the actual current draw of
the rasp drive motor to a predetermined target current draw and
adjust an operating characteristic of the tire buffer, such as the
traverse speed of the rasp pedestal across the width of the tire
casing being buffed, in response to any difference therebetween to
urge the actual current draw toward the target current draw. In
other embodiments, the operating parameter monitored and/or the
operating characteristic that is changed to change the monitored
operating parameter can be varied.
[0053] The tire buffer can automatically impart a predetermined
shoulder texture upon shoulders of the tire casing being buffed
with the texturing device.
[0054] Turning now to the Figures, an illustrative tire buffing
apparatus 100 is shown in FIG. 1. The tire buffer 100 can include a
base assembly 110, a rasp pedestal 112, a rasp pedestal moving
assembly 114, a tire hub assembly 116, an operator station 118, an
electrical enclosure 120, and a pneumatic enclosure 122.
[0055] Referring to FIGS. 1-4, the base assembly 110 includes a
bottom base plate 130 and a length of fencing 132. The base plate
130 can act to support the other components of the tire buffer. The
fencing 132 extends from the base plate 130 about a portion of the
perimeter of the plate. The fencing 132 can act as a partition to
prevent objects from unintentionally coming within the area of the
tire buffer.
[0056] The rasp pedestal moving assembly 114 can be provided to
selectively move the rasp pedestal 112 with respect to the tire hub
assembly 116. A control unit 140 housed in the electrical enclosure
120 can control the movements of the moving assembly. The moving
assembly 114 is disposed intermediate of the base plate 130 and the
rasp pedestal 112.
[0057] The rasp pedestal moving assembly 114 can include a runner
member 152, an X table 154, and a Y table 156. The runner member
152 can be secured to the base plate 130. The X table 154 is
movably mounted to the runner member 152 such that the X table is
movable along an X-axis. The Y table 156 is movably mounted to the
X table 154 such that the Y table 156 is movable along a Y-axis,
which is perpendicular to the X-axis.
[0058] The rasp pedestal 112 can be provided for removing tire
material from a tire casing mounted to the tire hub assembly 116 to
provide a predetermined, buffed tire casing profile having a
desired texture. The rasp pedestal 112 can be movably mounted to
the base plate 130 via the rasp pedestal moving assembly 114. The
rasp pedestal 112 is rotatably mounted to the Y table 156 such that
the rasp pedestal 112 is rotatable about a vertical Z-axis, which
is mutually perpendicular to the horizontal X-axis and the
Y-axis.
[0059] The rasp pedestal 112 is movable along the X-axis and the
Y-axis and rotatable about the Z-axis to follow a predetermined
buffing path which can vary depending on the make and size of the
tire casing to be buffed. The rasp pedestal 112 can move along the
predetermined the buffing path to define a desired, predetermined
tire casing profile. The control unit 140 can control the rasp
pedestal 112 through the moving assembly 114 to move along a
selected buffing path depending upon the type of tire casing to be
buffed, which information a user of the tire buffer 100 can input
to the control unit 140 via the operator station 118.
[0060] Referring to FIG. 4, the rasp pedestal 112 can include a
rasp head assembly 160, a drive motor assembly 162, and a pedestal
cover 164. The rasp head assembly 160 can include a rasp head 166
for removing material from the tire casing to be buffed and a
texturing device 168 for imparting a desired texture upon at least
a portion of the tire casing. The texturing device 168 can be in
the form of a wire brush. The rasp head 166 and the wire brush 168
can be rotatably mounted within upon a rasp shaft 170. The rasp
head 166 and the wire brush 168 can be disposed within a respective
housing of the assembly 160 such that they are aligned with a
respective opening therein to allow the rasp head 166 and the wire
brush 168 to be engageable with a tire casing mounted to the tire
hub assembly 116.
[0061] The motor assembly 162 is provided to selectively drive the
rasp head assembly 160. The drive motor assembly 162 includes a
rasp drive motor 180 operatively connected to the rasp head
assembly 160 via a belt which is in operative engagement with the
rasp shaft 170 and the motor 180. The drive motor 180 can comprise
a 25 Hp AC electric motor, for example. The drive motor 180 can be
selectively operated by the control unit 140 to selectively operate
the rasp head 166 and the texturing device 168 during the buffing
sequence. A current sensor 182 can be associated with the drive
motor and the control unit 140 such that the current sensor can
convey to the control unit 140 the current draw of the drive motor
180 during operation of the tire buffer 100.
[0062] Referring to FIGS. 2 and 3, for supporting and rotating a
tire casing during the buffing sequence, the tire hub assembly 116
can be provided. The tire hub assembly 116 can be mounted to the
base plate 130 at a predetermined location, which is known to the
control unit 140. The tire hub assembly 116 is disposed such that
the rasp pedestal 112 can be moved into operable engagement with a
tire casing mounted to the hub assembly 116 for performing a
buffing sequence.
[0063] The hub assembly 116 can include a tire chuck 190 for
mounting a tire casing thereto, an inflation system 192 for
inflating a tire casing mounted to the tire chuck 190, an expanding
rim mounted to the chuck 190 for accepting tire casings of variable
sizes, and a tire drive motor 196 and a gear box 198 for rotating
the chuck 190 about a hub axis 200. The hub assembly 116 can be
supported by a column assembly 204 with the gear box 198 extending
from the column assembly and with the motor 196 and the chuck 190
extending from the gear box 198. The column assembly 204 can extend
from a column mounting pad 208, as shown in FIG. 5. The tire drive
motor 196 can be a 5 Hp AC electric motor, for example. The control
unit 140 can selectively operate the tire drive motor 196 to rotate
a tire casing mounted to the tire chuck 190.
[0064] For convenient operation of the tire buffer 100, the
operator station 118 can be provided. The operator station 118
extends from the fencing 132 and is positioned to allow for
convenient observation of the rasp pedestal 112 and the hub
assembly 116. The operator station 118 includes a touch screen 220
which can receive and display information concerning the
characteristics and parameters related to the tire casing to be
buffed and operating parameters and characteristics of the tire
buffer 100. The operator station 118 can include a power switch 222
and an emergency-stop switch 224. A user can operate the tire
buffer 100 from the operator station 118 via the touch screen 220
to buff tire casings of different sizes and types. The touch screen
220 can act as an interface between the user and the control unit
140 housed in the electrical enclosure 120 for controlling the
operation of the tire buffer 100.
[0065] The electrical enclosure 120 is mounted to the base plate
130 and is disposed at a rear end 230 of the tire buffer 100. The
electrical enclosure 120 houses the control unit 140, the rasp
drive motor current sensor 182, other suitable controls, fuses,
relays, and other components associated with the electrical
requirements for operating the tire buffer 100. The pneumatic
enclosure 122 is mounted to the base plate 130 and is disposed
adjacent the electrical enclosure 120. The pneumatic enclosure 122
houses a pneumatic system for operating various components of the
tire buffer.
[0066] Referring to FIG. 2, the base assembly 110 includes a
plurality of leveling pads 236 mounted to the base plate 130 by a
corresponding plurality of leveling pad connectors 238. The
leveling pads 236 can be adjusted via the connectors 238 to
selectively move either away from or toward the base plate 130 for
leveling the base plate 130.
[0067] Below the touch screen 220 at the operator station 118, the
power switch 222 is provided for controlling the operation of the
tire buffer 100. The emergency stop 224 switch is also provided for
immediately stopping the operation of the tire buffer 100. An
electrical junction box 240 can be provided for housing various
components of the operator station 118.
[0068] Ductwork 250 can be mounted to the rasp pedestal 112 for
connecting the rasp pedestal to an appropriate dust collection
system. The dust collection system can be used to neatly convey
material removed from a tire casing during the buffing
operation.
[0069] Referring to FIG. 3, the operator station 118 can include a
mounting assembly 260 for supporting the touch screen 220. The
touch screen 220 is pivotally mounted to the mounting assembly 260.
The mounting assembly 260 can include a pivot mechanism 262 and a
lift mechanism 264. The pivot mechanism 262 can allow the touch
screen 220 to rotate about two perpendicular axes, a horizontal
axis 268 and the vertical Z axis. The lift mechanism 264 is
operable to selectively move the touch screen 220 along the
vertical Z axis. The lift mechanism 264 extends between the pivot
mechanism 262 and the fencing 132.
[0070] The pivot mechanism 262 can include an arm 270, a collar
272, and a bracket 274. The touch screen 220 is pivotally mounted
to the arm 270 at a distal end thereof such that the touch screen
220 can pivot about the horizontal axis 268. A proximal end of the
arm 270 is mounted to the bracket 274 with the arm 270 extending
through the collar 272. The arm 270 is rotatable with respect to
the collar 272 to allow the touch screen 220 to pivot about the
vertical Z axis.
[0071] The lift mechanism 264 includes a releasable ratchet
mechanism 280 which allows for selective, incremental movement of
the touch screen 220 along the vertical Z axis. The ratchet
mechanism 280 can be activated to prevent the touch screen 220 from
moving downward but allow the upward movement thereof and can be
disengaged to allow for both upward and downward movement thereof.
A knob 282 is associated with the ratchet mechanism 280 for
selective engagement thereof. The knob 282 is biased, by a spring,
for example, toward a fixed position wherein the ratchet 280 is
activated. The knob 282 can be moved to a released position wherein
the latching ratchet 280 is disengaged to allow the touch screen
220 to be lowered as desired. A grab handle 284 can be provided to
facilitate the adjustment of the touch screen 220.
[0072] Referring to FIG. 4, the tire buffer 100 is shown with the
tire chuck removed for illustrative purposes. The belt of the rasp
drive motor assembly 162 can be housed within a belt guard 290. The
rasp head assembly 160 is disposed at a top end 292 of the rasp
pedestal 112. The belt guard 290 extends between the rasp drive
motor 180 and the rasp head assembly 160.
[0073] Referring to FIG. 5, the base assembly 110 of the tire
buffer is shown. The runner member 152 includes a pair of X rails
300, 301 in predetermined, spaced relationship to each other. The X
table 154 can be slidably mounted to the X rails 300, 301 of the
runner member. The X rails 300, 301 are in substantially parallel
relationship to each other and extend longitudinally along the X
axis. The X table 154 includes a plurality of bearing blocks, a
pair of bearing blocks for each X rail in this embodiment, disposed
on its underside which are arranged to ride upon the X rails 300,
301.
[0074] An X actuator 308 can be provided to allow the X table 154
to be movable with respect to the runner member 152, which is fixed
with respect to the base plate 130. The X actuator 308 is disposed
between the X rails 300, 301 and is mounted to the base plate 130.
The X actuator 308 includes a servomotor 310 operably connected to
a ball screw 312 via a coupling device 314. A bearing 316 can be
provided to support the ball screw 312. A ball nut is disposed on
the ball screw 312 and mounted to the X table 154 for allowing the
X table to move along the X rails 300, 301 upon actuation of the X
actuator 308. A plurality of X proximity sensors 318 is disposed in
respective predetermined locations along the X axis to designate
first and second X limit positions, which delineate the range of
travel of the X table along the X axis, and an X home position. The
X proximity sensors 318 are electrically connected to the control
unit 140. The X table 154 can include a flag portion that is
disposed on the table such that it can be operatively arranged with
the X proximity sensors 318 to trip the sensors upon the flag
portion being moved within a predetermined distance thereof. The X
table 154 and base plate 130 can include mechanical stops which
provide a supplemental system for ensuring that the X table 154
does not travel beyond a predetermined range of travel over the X
axis.
[0075] The Y table 156 can be slidably mounted to a pair of Y rails
320, 321 secured to the X table 154. The X table 154 includes a
pair of Y rails 320, 321 in predetermined, spaced relationship to
each other. The Y rails 320, 321 are in substantially parallel
relationship to each other and extend longitudinally along the Y
axis. The Y table 156 includes a plurality of bearing blocks, a
pair of bearing blocks for each Y rail 300, 301, disposed on its
underside which are arranged to ride upon the Y rails 156.
[0076] A Y actuator 328 can be provided to allow the Y table 156 to
be movable with respect to the X table 154. The Y actuator 328 is
disposed between the Y rails 320, 321 and is mounted to the X table
154. The Y actuator 328 includes a servomotor 330 operably
connected to a ball screw 332 via a coupling device 334. A bearing
336 can be provided to support the ball screw 332. A ball nut is
disposed on the ball screw 332 and mounted to the Y table 156 for
allowing the Y table 156 to move along the Y rails 320, 321 upon
actuation of the Y actuator 328. A plurality of Y proximity sensors
can be disposed in respective predetermined locations along the Y
axis to designate first and second Y limit positions, which
delineate the range of travel of the Y table 156 along the Y axis,
and a Y home position. The Y table 156 can include a flag portion
that is disposed on the table such that it can be operatively
arranged with the Y proximity sensors to trip the sensors upon the
flag portion being moved within a predetermined distance thereof.
The Y proximity sensors are electrically connected to the control
unit. The Y table 156 and the X table 154 can include mechanical
stops which provide a supplemental system for ensuring that the Y
table 156 does not travel beyond a predetermined range of travel
over the Y axis.
[0077] The X and Y actuators 308, 328 can be electrically operated
and driven in a conventional manner via the control unit. The X and
Y home positions can be used to place the rasp pedestal in a
predetermined location, a home position, at the initiation of a
buffing sequence.
[0078] Referring to FIGS. 6-8, the rasp pedestal 112 of the tire
buffer is shown with the belt guard and the pedestal cover removed.
Referring to FIG. 6, the rasp pedestal 112 includes a support
assembly 350. The support assembly 350 is constructed to carry the
rasp head assembly 160 and the motor assembly. The support assembly
350 includes a rasp support plate 352, a pair of support legs 354,
a transverse support member 356 extending between the legs 354, and
a rasp head mounting plate 358. Each support leg 354 can be a
hollow square tube. The transverse support member 356 can include a
junction box 362 for housing electrical components of the rasp
pedestal 112. The rasp support plate 352 is suitably mounted to the
Y table 156 to allow for rotational movement of the rasp pedestal
112.
[0079] A pair of bumper stops 366 extends from the rasp support
plate 352. The bumper stops 366 can be arranged with stops mounted
to the Y table to provide a mechanical system for delineating an
arc over which the rasp pedestal 112 can rotate. The rasp pedestal
112 can also be arranged with three proximity sensors mounted to
the Y table which can function to delineate limit positions of the
arc of travel for the rasp pedestal 112 and a home position for the
rasp pedestal 112. The support from which the bumpers 366 extend
can act as a flag portion which can be operatively arranged with
the proximity sensors to trip the sensors upon the flag portion
being moved within a predetermined distance thereof.
[0080] The rasp head assembly 160 can house the rasp head 166 and
the wire brush 168. The rasp head assembly 160 can be mounted to
the rasp head mounting plate 358. The rasp head assembly 160
includes a bearing housing 380, a rasp hood 382, a brush hood 384,
and a buffing assembly 386 extending therethrough. The rasp hood
382 can have a screen cover 390 which can allow air to pass
therethrough while keeping the area clean. The rasp head assembly
160 can include a plurality of water supply lines 392 for spraying
the interior of the rasp hood 382 to cool the rasp 166 during the
buffing sequence.
[0081] The rasp hood 382 and the brush hood 384 each include a
respective opening 396, 398 therein to allow the rasp 166 and the
brush 168 to engage a tire casing mounted to the tire hub assembly.
The openings 396, 398 are contoured, as shown in FIG. 8, to
complement the circumference of a tire casing being buffed. Each
opening 396, 398 has a perimeter with a bristle strip 400
projecting therefrom. The bristle strips 400 can conformingly
engage a tire casing mounted to the tire hub during the buffing
sequence to prevent tire casing material removed by the rasp 166 or
the brush 168 from exiting the respective opening 396, 398. The
bristle strips 400 can also facilitate the collection system by
providing a seal with the tire casing to increase the suction power
of the collection system.
[0082] Referring to FIGS. 6 and 8, a vertically-disposed belt cover
plate 420 depends from the bearing housing 380 and includes
mounting tabs 422, 424 for cooperative engagement with the belt
guard. A belt guard proximity sensor 426 can be provided to detect
whether the belt guard is mounted to the cover plate 420. Referring
to FIG. 6, the rasp pedestal 112 can include an emergency-stop
switch 430 for selectively terminating the operation of the tire
buffer 100. The emergency stop switch 430 can be mounted to the
cover plate 420 via a bracket 432.
[0083] Referring to FIG. 7, the rasp support plate 352 includes an
opening 440 for a rotor assembly for selectively rotating the rasp
pedestal 112 about the Z axis and a pass-through hole 442 for cable
and other electrical connections.
[0084] Referring to FIGS. 7 and 8, an elbow 450 is connected to a
conduit 452 extending from the rasp pedestal 112 for inclusion in
the collection system. The elbow 450 can include a blast gate 454,
butterfly valve, or other damper, for selective operation of the
collection system. The damper 454 can be manually operated. In
other embodiments, the damper can be configured to automatically
move to an open position for as long as the rasp drive motor is
running to allow the collection system to remove debris from the
rasp pedestal 112 generated during the buffing sequence and to a
closed position when the rasp drive motor is not running.
[0085] Referring to FIG. 9, the rasp drive motor 180 is disposed
adjacent a bottom end of the rasp pedestal 112. The rasp drive
motor 180 can support a junction box 460 for housing electrical
wiring connected to the motor 180 for operation thereof. The belt
462 can be operatively arranged with the motor 180 and the rasp
shaft 170 to allow the motor to selectively rotate the rasp shaft
about a longitudinal axis 464 of the rasp shaft. The belt 462 is
disposed around a pair of pulleys respectively associated with the
motor 180 and the rasp shaft 170.
[0086] The rasp drive motor 180 is pivotally mounted to the rasp
support plate 352 to allow for selective adjustment of the tension
of the belt 462. A pivot rod 470 is journaled between a pair of
saddle brackets 472 disposed adjacent each end thereof. A mount 474
is connected to the pivot rod 470 at a first end thereof. The motor
180 is mounted to the mount 474 such that the motor 180 can rotate
about the pivot rod 470. A plurality of bolts 476 extends through
the mount 474 at a second end thereof with the bolts 476 extending
through the rasp support plate 352. Each bolt 476 bears against a
circular rod 478, also shown in FIG. 7, attached to the mount 474
for allowing the mount 474 to pivot while still providing a bearing
point for the rasp drive motor 180. Each bolt 476 includes a pair
of nuts 480, 481, one being disposed above the rasp support plate
352 and the other disposed below it to allow the second end of the
mount 474 to be positioned in spaced relationship to the support
plate 352. The position of the second end of the mount 474 can be
adjusted by manipulating the nuts as desired. The motor 180 can be
pivoted about the pivot rod 470 either toward or away from the rasp
support plate 352 to adjust the tension placed upon the belt 462.
The belt cover plate 420 includes an elongated slot 484 to
accommodate movement of the rasp drive motor 180.
[0087] The rasp pedestal 112 can include a rotator assembly 490 for
selective rotational movement of the rasp pedestal 112. The rotator
assembly 490 can include a shaft 492 with a torque arm 494
connected thereto, a rotator bearing housing 496, a gearbox 498,
and a rotator actuator 500, in the form of a servomotor in this
embodiment. The shaft 492 is operatively attached to the gearbox
498. The shaft 492 extends from the gearbox 498 and through a
portion of the Y table 156 with a free end of the shaft extending
beyond the Y table. The torque arm 494 extends from the free end of
the shaft and is in operative engagement with the Y table 156 to
prevent the shaft 492 from rotating with respect to the Y table.
The gearbox 498 includes a housing 502 and a stub shaft. The stub
shaft of the gearbox 498 is coupled to the shaft 492. The housing
502 of the gearbox 498 can rotate with respect to the Y table 156
upon actuation of the rotator actuator 500. The gearbox housing 502
has a flange 504 extending therefrom. The flange 504 can be mounted
to the rasp support plate 352 of the rasp pedestal via bolts, for
example, extending through mounting holes in the flange and the
rasp support plate. The rasp support plate 352 includes the opening
440, shown in FIG. 7, therein to accommodate the rotator bearing
housing 496.
[0088] Referring to FIGS. 9 and 10, the rasp pedestal 112 can
include a tire measurement mechanism 520 for measuring the size of
a tire casing mounted to the tire hub assembly. The tire
measurement mechanism 520 can include a proximity sensor 522 and a
sprocket 524. The proximity sensor 522 is disposed adjacent the
sprocket 524 and operatively arranged to detect movement of the
sprocket 524. The proximity sensor 522 is mounted to the belt cover
plate 420 which extends from the rasp head assembly 160. The
proximity sensor 522 is connected to a bracket 526 which is movably
mounted to the cover plate 420. The bracket 526 includes a pair of
elongated slots 528 which can accommodate a pair of bolts 530,
respectively, therethrough. The bolts 530 can extend through the
cover plate 420 for securing the bracket 526 thereto. The bracket
526 can move with respect to the bolts 530 and the cover plate 420
over a range of travel defined by the elongated slots 528. The
position of the proximity sensor 522 can be adjusted by moving the
bracket 526 to ensure that the proximity sensor 522 is positioned
to detect movement of the sprocket 524.
[0089] The proximity sensor 522 is electrically connected to a
power source via a line which can be secured to the cover plate 420
by a clip, as shown in FIG. 9. The proximity sensor 522 can send a
signal through the line to the control unit of the tire buffer upon
sensing the movement of the sprocket 524.
[0090] The sprocket 524 is mounted to the rasp shaft 170. The
sprocket 524 can rotate upon the rotation of the rasp shaft 170.
The proximity sensor 522 is positioned with respect to the sprocket
524 such that the proximity sensor will be deactivated when a
valley 534 of the sprocket is in its sensing field and will be
activated when a tooth 536 of the sprocket is in its sensing field.
By changing conditions upon movement of the teeth of the sprocket,
the sprocket proximity sensor 522 can signal the control unit that
the sprocket 524 is moving.
[0091] To determine the size of the tire, the rasp pedestal 112 can
be moved from a known, home position toward a tire casing 550
mounted to the tire hub assembly. The tire hub assembly can be
located at a second, known position. The control unit can monitor
the distance the rasp pedestal 112 moves from the home position.
The tire hub assembly can be activated to rotate the tire casing
mounted thereto. The rasp head 166 of the rasp pedestal can be
aligned with the tire casing 550. Once the rasp 166 is brought into
contact with the rotating tire casing 550, the rasp 166 will begin
to rotate in response, which in turn causes the rasp shaft 170 and
the sprocket 524 to rotate. The proximity sensor 522 can signal the
control unit that the sprocket 524 is moving whereupon the control
unit can direct the rasp pedestal 112 to stop moving toward the
tire hub assembly. The control unit can determine the size of the
tire casing 550, for example the tire casing diameter, by comparing
the known position of the tire hub assembly 116 with the position
of the rasp pedestal 112 at the time the sprocket 524 first began
to move.
[0092] Referring to FIG. 9, the rasp pedestal 112 can include a
tire location sensor mechanism 570, which can be provided to
facilitate the tire measurement operation and to reduce the time
require to complete the measurement operation. The tire location
sensor mechanism 570 can include a tire sensor 572 and mounting
member 574. The mounting member 574 is mounted to the rasp head
assembly 160 and can act to support the tire sensor 572. The tire
sensor 572 can be electrically connected to the control unit by way
of a line. The tire sensor 572 is positioned to detect the tire
casing 550 mounted to the tire hub assembly upon the rasp pedestal
112 being disposed within a predetermined distance from the tire
hub assembly. The tire sensor 572 is oriented such that a photo
beam that it can emit is directed toward the tire casing 550
mounted to the tire hub assembly. The rasp pedestal 112 can be
moved toward the tire hub assembly at a first rate of speed until
the tire casing 550 mounted to the tire hub assembly trips the tire
sensor 572. The tire sensor 572 can be tripped at a point where the
rasp pedestal 112 is not contacting the tire casing 550. The tire
sensor 572 can send a signal to the control unit which in response
slows the rasp pedestal 112 to a second rate of speed suitable for
allowing the tire measurement mechanism 520 to operate. The rasp
pedestal 112 can advance toward the tire casing 550 at the slower,
second rate of speed to perform the tire measurement operation,
stopping upon the tire measurement mechanism 520 sensing the
contact of the tire casing with the rasp.
[0093] Referring to FIG. 9, the rasp pedestal 112 can include a
rasp sharpening system 590 for periodically sharpening the rasp
head. The rasp sharpening system 590 can include a plurality of
sharpening stones disposed with the rasp head assembly, a pivotable
lever arm 592 to which the stones are mounted, and a cylinder 594
for selectively pivoting the lever arm 592. Actuating the cylinder
594 can operate the sharpening system 590. The cylinder 594 can be
mounted to a distal end of the lever arm 592. When the cylinder 594
is actuated, the cylinder 594 can move in an actuating direction
596 with the lever arm 592 rotating in response to bring the
sharpening stones into operative engagement with the rasp head 166.
The sharpening stones can act to knock off any edges present on the
blades of the rasp head and to trim the blades such that they
extend from the hub of the rasp a uniform distance. The sharpening
system 590 can be operated automatically via the control unit after
the tire buffer 100 has buffed a predetermined number of tire
casings.
[0094] Referring to FIGS. 1I and 12, a buffing assembly 600 of the
rasp head assembly is shown. The wire brush 168 and the rasp 166
can be mounted to the rasp shaft 170. Referring to FIG. 11, the
rasp shaft 170 includes a mounting shoulder 610, against which the
rasp head 166 can be abutted. A first spacer column 612 can be
disposed over the rasp shaft 170 between the rasp head 166 and the
wire brush 168. The spacer column 612 is generally cylindrical and
configured to accommodate the rasp shaft 170. The first spacer
column 612 can engage a hub portion of the rasp head 166 and a hub
portion of the wire brush 168. A second spacer column 614 is
provided between the wire brush 166 and a rasp nut 618. The rasp
nut 618 can be threadedly secured to a threaded end 620 of the rasp
shaft to capture the wire brush 168 and the rasp head 166 in
predetermined arrangement such that the wire brush and the rasp
head are aligned with the respective openings of the brush hood and
the rasp hood. The rasp nut 618 can be threaded onto the rasp shaft
170 until the rasp nut drives the second spacer column 614, the
wire brush 168, the first spacer column 612, and the rasp head 166
into contacting relation with the mounting shoulder 610 of the rasp
shaft. The rasp head 166 and the wire brush 168 are in constrained
relationship with the rasp shaft 170 via the rasp nut 618 and the
mounting shoulder 610 with the spacer columns 612, 614 therebetween
such that the wire brush and the rasp head rotatively secured to
the rasp shaft, rotating with the rasp shaft upon it being rotated
by the rasp drive motor.
[0095] In other embodiments, the wire brush and the rasp head can
be mounted to the rasp shaft using any suitable technique.
[0096] Referring to FIG. 11, the bearing housing 380 can help to
retain the rasp shaft 170 such that the rasp shaft is constrained
from moving with respect to the bearing housing 380 along the
longitudinal axis 464 of the rasp shaft. The bearing housing 380
and the rasp shaft 170 can be in sealing relationship to each other
with the rasp shaft free to rotate about its longitudinal axis 464.
A seal 630 can be disposed around the rasp shaft 170 such that it
is in contacting, sealing relation to an outer surface of the rasp
bearing housing 380. The seal 630 can be made from rubber or any
other suitable material. The bearing housing 380 includes a first
and a second bearing portion 632, 634, with each bearing portion
comprising a plurality of ball bearings disposed in a ring around
the rasp shaft 170. The bearing portions 632, 634 are constrained
from moving with respect to the longitudinal axis 464 of the rasp
shaft by a first and a second cover plate 638, 640 of the bearing
housing, a pair of snap rings 642, 643, and an intermediate collar
portion 648 of the rasp shaft 170 disposed between the first and
second bearing portions 632, 634. One of the snap rings 642 is
disposed in a groove encircling the rasp shaft adjacent the first
cover. The other snap ring 643 is disposed in a recess in a body
654 of the bearing housing. The first and second covers 638, 640
can be removable from the body 654 of the bearing housing by being
removably bolted thereto.
[0097] The body 654 of the housing can include a grease port 658
which communicates with a bearing cavity 662 for supplying grease
or other lubricant to the first and second bearing portions 632,
634.
[0098] The rasp bearing housing 380 can include a detent cylinder
680 which is selectively engageable with the rasp shaft 170 to
prevent the rasp shaft from rotating. The detent cylinder 680 can
be mounted to the body 654 of the rasp bearing housing by a
plurality of bolts. The detent cylinder 680 can be inserted into a
bore 684 in the rasp shaft 170 to lock the rasp shaft in place. The
detent cylinder 680 can be pneumatically driven and can be operated
through the user interface disposed on the touch screen. With the
rasp shaft 170 locked in place the retaining nut 618 can be removed
from the rasp shaft 170 to allow the wire brush 168 and the rasp
head 166 to be withdrawn from the rasp shaft.
[0099] Referring to FIGS. 13-16, the rasp head assembly 160 is
shown. Referring to FIG. 13, the brush hood 384 includes a door 690
which can be disposed in a closed position and in the open
position, as shown in hidden lines. The door 690 is pivotally
mounted at its lower end to a carriage 692 which is captured within
a slot 696. The door 690 can be held in the closed position by a
latch mechanism 700. The door 690 can be moved to the open position
with the carriage 692 in an upright position, as shown in full
lines, to allow the nut to be removed from the rasp shaft 170. With
the nut removed, the wire brush 168 can be removed from the rasp
shaft 170. The carriage 692 can be translated in a removal
direction 704 until it is sufficiently clear of the rasp head
mounting plate 358 to permit it to rotate downward about a pivot
708. With the carriage 692 disposed in a lowered position, as shown
in hidden lines in FIG. 11, the rasp 166 can be removed from the
rasp shaft 170.
[0100] Referring to FIG. 14, the latch mechanism 700 can also
include a tab 712 which can extend through an opening 714 to help
secure the door 690 in place and to provide a second locking point
between the brush hood and the door.
[0101] Referring to FIG. 15, a conduit 730 can be associated with
the brush hood 384 to provide a connection point for a collection
system to remove any debris generated during a texturing operation
of the buffing sequence.
[0102] Referring to FIG. 16, a detent proximity sensor 740 can be
provided to detect whether the detent cylinder 680 is engaged with
the rasp shaft 170. The detent proximity sensor 740 can be
electrically connected to the control unit and arranged with the
detent cylinder to sense whether the cylinder is in a normal
position or in an extended position for engagement with the rasp
shaft 170.
[0103] Referring to FIG. 17, the rasp head assembly includes an
opening 748 to which the ductwork can be alignedly mounted for
allowing debris generated during the main buffing operation of the
buffing sequence to be conveyed through the ductwork via the dust
collection system. The opening 748 can have an eight-inch diameter,
for example.
[0104] Referring to FIG. 18, the rasp hood 382 of the rasp head
assembly can be mounted to the body 654 of the bearing housing 380
via a plurality of bolts.
[0105] Referring to FIGS. 19 and 20, the rasp head 166 of the
buffing assembly is shown. The rasp 166 can be any suitable rasp,
such as a rasp available from B&J Manufacturing Co., marketed
under the name of "Rocket Rasp." The rasp head can include an
abrasive serrated edge 770 which can be of conventional
configuration. The rasp 166 can include a plurality of rasp blades
772 disposed in alternating fashion. In the illustrative rasp head,
the rasp include four quadrants 775, 776, 777, 778 wherein the
blades 772 within a particular quadrant are arranged parallel to
each other and the blades 772 of adjacent quadrants are arranged in
alternating, opposing relationship to each other. The alternating,
offset arrangement of the four quadrants 775, 776, 777, 778 of
blades of the rasp head can provide an overlapping cutting effect
for efficient tread removal during the buffing sequence.
[0106] Referring to FIGS. 21 and 22, the wire brush 168 of the
buffing assembly is shown. The wire brush 168 acts as a
shoulder-texturing device. The wire brush 168 can be any suitable
brush, such as a brush available from Osborn International of
Cleveland, Ohio, identified as part number 220-80. The brush 168
can have a diameter of about eight inches, for example. The width
of the brush can be about 11/4 inches, for example. The diameter of
each wire of the brush can be about 0.0104 inches, for example. The
wire bush can have a speed rating of about 4500 rpm, for example.
In other embodiments, any other suitable wire brush can be used. In
other embodiments, a stone cup can be used as a shoulder-texturing
device.
[0107] Referring to FIG. 23, a touch screen display 800 is shown.
The touch screen display 800 can be displayed on the touch screen
at the operator station. The operator can interact with the display
800 to program the tire buffer to operate according to
predetermined sequences based on the input information for the
displayed parameters. The first touch screen display 800 can
include a "recipe" portion 802 wherein characteristics of the tire
casing to be buffed and the depth of cut for the rasp head can be
displayed and adjusted. The recipe portion provides a user with
convenient access to tire characteristics for commonly buffed tire
casings which can be recalled by recipe number.
[0108] A target radius 804 of the tire after being buffed can be
entered on the touch screen. The rasp pedestal of the tire buffer
can run through a sequence based on the entered information for
buff radius to buff a tire casing mounted on the tire hub assembly
116. The operator can enter different buff radii over a
predetermined range of radii by interfacing with the control unit
through the touch screen.
[0109] The control unit can move the rasp pedestal along a
predetermined buffing path which can be based upon the type of tire
casing being buffed. The buffing path can include a plurality of
passes wherein the rasp pedestal moves the rasp head transversely
across the width of the tire casing to define the predetermined
tire casing profile. A rasp head depth of cut 806 can be displayed
on the first display 800 of the touch screen as a value of inches.
The depth of cut indicates the distance of overlap in a pass
between the rasp head and a tire casing mounted to the tire hub
assembly for buffing, i.e., the depth of cut is the distance the
rasp head is inserted into the tire casing as it moves transversely
across the width of the tire casing in a pass of the buffing path.
The user can change the value of the rasp depth of cut by
interfacing with the control unit via the touch screen.
[0110] The control unit can manipulate the rasp pedestal with
respect to a tire casing mounted to the tire hub assembly to
perform a shoulder trimming operation. A trim angle 808 can be
displayed on the first display 800 of the touch screen to indicate
to the user that angle at which the shoulder will be trimmed by the
rasp head of the rasp pedestal 112. The user can change the value
of the shoulder trim angle by interfacing with the control unit via
the touch screen.
[0111] The operator can designate the type of tire being buffed by
interfacing with the control unit via a "tread" portion 810 of the
first display of the touch screen. The tread portion 810 includes
areas where the user can input a tread name, a tread type, and a
tread size, for example.
[0112] The display can indicate the mode in which the tire buffer
100 is operating by lighting an indicator bar 812 to indicate which
operation the tire buffer 100 is currently performing, such as a
measuring operation, a sharpening operation, a brushing operation
(also called a texturizing operation), and a trimming operation,
for example.
[0113] The display can include a rasp drive current indicator 820
provided to indicate the measured current draw of the rasp drive
motor expressed as a percentage of a predetermined, full-load
current value. The indicator can include a bar graph 822 having
indicia to indicate the measured current value, for example over a
range of 0% to about 175%. The bar graph 822 can be illuminated
from the 0 indicia to the measured value to provide a readily
readable visual indication of the measured current draw of the rasp
drive motor.
[0114] The display 800 can also display information pertaining to
the components of the tire buffer 100. For example, the display can
indicate the wear on the rasp by displaying the number of tires the
buffer can buff before the next scheduled sharpening of the
rasp.
[0115] The display can include an operating portion 830 which can
allow the user to interface with the control unit to operate the
tire buffer 100. The operating portion can include a start button
832, an abort button 834, and a pause button 836, which the
operator can press to start, stop, and pause the tire buffing
sequence, respectively.
[0116] Referring to FIG. 24, a second touch screen display 850 is
shown. The second display 850 can allow a user to establish values
for predetermined parameters of the tire buffer. For example, the
display includes areas 854, 855, 856 where the operator can define
points at which the three water lines which communicate with the
interior of the rasp hood open to direct water onto the rasp head
during the buffing sequence. The user can direct the control unit
to open the three water valves independently based on the measured
current draw of the rasp drive motor. In the illustrative
embodiment, the first valve is programmed to open once the rasp
drive current draw reach a first value, 45% of a predetermined full
load current draw. The second valve is programmed to open once the
rasp drive current draw reaches a second value, 65% of the
full-load current draw. The third valve is programmed to open once
the rasp drive current draw reaches a third value, 85% of the
full-load current draw. The second touch screen display 850 can
allow these values to be changed by the user by interfacing with
the screen and inputting new values.
[0117] The control unit can advance the rasp pedestal toward the
tire casing during a shoulder texturizing operation until the
measured current draw of the rasp drive motor reaches a
predetermined value, for example. The user can set the shoulder
texturizing value through interfacing with the touch screen using
the second touch screen display 850 at a shoulder texturizing area
860. For example, the illustrative embodiment indicates the
shoulder texturizing value is 20% of the full-load current draw of
the rasp drive motor. The shoulder texturizing value can be changed
by the user through interfacing with the second touch screen
display to input a new value.
[0118] The second touch screen 850 can be used to control other
operating parameters of the tire buffer 100, such as the number of
tires which can be buffed between rasp head sharpenings and tire
inflation timing conditions, for example.
[0119] Referring to FIG. 25, a tire casing 875 is shown which
includes a tire casing profile 878 that can be defined by the tire
buffer. Once buffed by the tire buffer, a replacement tread 880 can
be applied to the tire casing, with a layer of cushion gum 882
disposed therebetween, according to any known method. The tire
casing 875 includes a crown portion 890 bounded on each side by a
respective shoulder portion 892 and a respective side wall 894. The
tire casing 875 can include a belt package 896 underlying the crown
890. The crown 890 and the shoulders 892 of the casing 875 present
a tire casing profile 878 that can be suitably formed to a
predetermined configuration with the tire buffer.
[0120] The surface of the crown 890 can be mechanically buffed to
provide a textured, convex arcuate configuration in a direction
transverse to the circumference of the casing 875. The arc can have
a characteristic radius of curvature, i.e., the crown radius
R.sub.c, which can generally corresponds to the upper contour of
the belt package 896, extending above the top belt by a
predetermined thickness, such as {fraction (3/32)} of an inch, for
example. The length of the arc at the crown radius extending
between the shoulders 892 defining the crown 890, i.e., the crown
arc width AW.sub.c, can be set at a predetermined value. The crown
radius R.sub.c and the crown arc width AW.sub.c can be
characteristic to tire casings of particular models and/or sizes of
tires. The tire casing from each variety of new tire can have a
characteristic crown radius and crown arc width.
[0121] The shoulders 892 of the tire casing 875 can also be
contoured in the shape of convex arcs which can have a
predetermined buffed shoulder radius R.sub.s that can be
substantially less than the crown radius R.sub.c. For example, for
casings having a buffed crown radius R.sub.c of from about twenty
inches to about thirty inches, the corresponding shoulder radius
R.sub.s can be in the range from about 0.3125 inches to about 1.625
inches. A typical shoulder radius R.sub.s can be about one
inch.
[0122] The crown radius R.sub.c of the buffed tire casing is a
characteristic of the particular tire from which the casing 875
derives and can vary from tire to tire. A common predetermined
crown arc width AW.sub.c can be accommodated by casings derived
from a variety of sizes of new tires, notwithstanding their having
different crown radii R.sub.c, particularly when the shoulder of
the tire casing 875 is formed as a convex arc in the manner of the
illustrative shoulders 892 shown in FIG. 25. The crown arc width
AW.sub.c can be chosen to approximate the tread width of the new
tire from which the tire casing 875 derives. To approximate the
tread widths of a range of tires, the crown arc width AW.sub.c can
be chosen as a median new tire tread width for tires in a series
from which the tire casing 875 derives. Preferably, the crown arc
width AW.sub.c is less than the width of the tread by about
{fraction (1/16)}.sup.th of an inch.
[0123] The crown radius R.sub.c of the tire casing can be in the
range of about 20 inches to about 32 inches, for example. Larger
crown radii, up to about 52 inches, for example, can be buffed
using the tire buffer. For tires having a crown radius R.sub.c in
the range of about 20 inches to about 32 inches, the corresponding
crown arc width AW.sub.c can be in the range of about 7.9 inches to
about 9.8 inches.
[0124] Referring to FIG. 26, another tire casing 898 is shown with
shoulders 899 that are substantially planar. Faces 900 of the
shoulders 899 can be disposed at opposing shoulder angles 904,
measured with respect to the radial axis of the tire casing 898, of
about 48.degree., for example.
[0125] Referring to FIGS. 27-31, a tire buffing sequence performed
by the tire buffer 100 of the present invention is illustrated.
[0126] Referring to FIG. 27, a tire casing 950 is mounted to the
tire hub assembly 116 such that the radial axis of the tire casing
is substantially parallel to the X axis. The rasp pedestal 112 of
the tire buffer 100 is disposed in a home position 952. The rasp
pedestal 112 can be placed in the home position via the control
unit which is electrically connected to the X and Y home position
sensors. The tire buffer 100 can accommodate a tire casing having
different diameters. The operator can initiate the buffing sequence
via the touch screen 220.
[0127] Referring to FIG. 28, the tire buffer 100 can perform a tire
casing measurement operation. The rasp pedestal 112 can be moved
from the home position along the Y axis until it is substantially
aligned with the tire casing 950 along the Y axis. The rasp
pedestal 112 can be advanced along the X axis toward the tire hub
assembly 116 while tire hub assembly 116 rotates the tire casing
950. The rasp pedestal 112 can be advanced toward the tire casing
950 at a first rate of speed until the tire locating sensor 570
detects that the rasp pedestal 112 is within a predetermined
distance from the tire casing 950 whereupon the locating sensor 570
can signal the control unit 140. The control unit 140 can slow the
rasp pedestal 112 to a second rate of speed convenient for
performing the tire measurement operation. The rasp pedestal 112
can advance along the X axis toward the tire casing 950 at the
second rate of speed until the tire measurement mechanism 520
detects that the rasp 166 has engaged the tire casing 950.
[0128] To determine the size of the tire casing 950, the control
unit 140 can monitor the position of the rasp pedestal 112,
tracking its movement from the known, home position to the position
it is in when the tire measurement mechanism 520 detects that the
rasp has engaged the tire casing. The tire hub assembly 116 can be
located at a second, known position. Once the rasp is brought into
contact with the rotating tire casing, the rasp will begin to
rotate in response, which in turn causes the rasp shaft and the
sprocket to rotate. The proximity sensor of the tire measurement
mechanism can signal the control unit that the sprocket is moving
whereupon the control unit can direct the rasp pedestal 112 to stop
moving toward the tire hub assembly 116. The control unit 140 can
determine the size of the tire casing 950, for example the tire
casing diameter, by comparing the known position of the tire hub
assembly 116 with the position of the rasp pedestal 112 at the time
the sprocket first moves.
[0129] The tire measurement can be taken anywhere along the width,
measured along the Y axis, of the tire casing 950 to allow an
operator to identify a high side, for example. In the case where
the tire casing has such a high side, the operator can measure the
size of the tire casing by positioning the rasp head to be aligned
with the identified high side.
[0130] Once the size of the tire is determined, the control unit
can move the rasp pedestal 112 through a buffing path based on the
type and size of the tire casing being buffed, for example. The
rasp pedestal 112 can be moved through a plurality of passes
wherein the rasp pedestal 112 is moved transversely across the
width of the tire casing to buff the tire to a predetermined buffed
size with a predetermined tire casing profile. The rasp pedestal
112 can be moved along the X and Y axes and rotated about the Z
axis while moving through the buffing path to achieve the desired
buffed tire casing.
[0131] The rasp head 166 can be set at a predetermined depth of cut
for each pass of the buffing path such that the rasp head cuts into
the tire casing 950 a predetermined amount in a direction
perpendicular to the direction of travel of the rasp head along the
buffing path.
[0132] Referring to FIG. 29, the tire buffer 100 can perform an
adjusting sequence for increasing the efficient removal of tire
material during the buffing operation. The control unit can monitor
an operating parameter of the rasp pedestal 112 or the tire hub
assembly 116 during the buffing sequence. A predetermined target
value for the selected operating parameter TVP can be calculated.
The control unit can compare the actual value of the operating
parameter AVP to the calculated target value of the parameter TVP
and adjust an operating characteristic OC of the rasp pedestal 112,
the tire hub assembly 116, or both to control the actual value of
the operating parameter AVP such that it is urged toward the
calculated target value of the operating parameter TVP. In the
event that the actual value of the operating parameter AVP is equal
to the target vale of the operating parameter TVP, the control unit
can maintain the operating characteristic OC at its current
condition.
[0133] In one embodiment, the control unit can monitor the current
draw of the rasp drive motor, for example. The rasp drive motor can
have a predetermined full-load capacity at which its current draw
is a particular value and at which the motor can remove material
from the tire casing at an efficient rate while preventing damage
to the motor or other components of the tire buffer. The value of
the predetermined target current draw can be based upon such
considerations as the capabilities of the motor driving the cutter,
the maximum depth of cut for the selected cutter, the maximum
traverse speed the buffer is capable of generating, and the wear of
the cutter itself. The control unit can compare the actual current
draw of the rasp drive motor to the calculated target current draw
and determined whether the actual current draw is equal to the
target current draw. If the actual and target current draws are
different, the control unit can move the rasp pedestal at different
rates of speed by selectively controlling the rasp moving assembly
to adjust the actual current draw such that it moves toward the
target current draw. The traverse rate of speed of the rasp
pedestal can be increased to increase the actual current draw of
the motor and decreased to decrease the actual current draw of the
motor. The depth of cut and the rate of rotation of the tire casing
can remain constant during the buffing operation.
[0134] In another embodiment, the rasp cutter speed can be
determined by the operator before the buffing operation, and the
feed rate, the depth of cut of the rasp head, can be adjusted
during buffing based on the difference between actual current draw
and the predetermined target current draw of the rasp drive motor.
A finishing pass or passes can be performed to define the tire
casing profile.
[0135] In other embodiments, the current draw of the tire drive
motor, the speed of the rasp drive motor, or the speed of the tire
drive motor, for example, can be monitored. In other embodiments,
the depth of cut of the rasp head or the rotational speed of the
tire casing can be adjusted to adjust the actual value of the
selected operating parameter.
[0136] Referring to FIG. 30, tire buffer 100 can perform a shoulder
trimming operation. The control unit can engagingly position the
rasp head of the rasp pedestal 112 with respect to the tire casing
950 to perform the shoulder trimming operation in shoulder
positions on both sides of the tire casing. The shoulder positions
can be mirror images to each other about the X axis. The shoulders
956 can be formed at a predetermined angle based on the type of
tire casing being buffed. The shoulders can be defined to be
substantially planar faces disposed at a predetermined shoulder
angle. In other embodiments, the shoulders can be contoured having
their own predetermined shoulder radius.
[0137] Referring to FIG. 31, the tire buffer 100 can perform a
shoulder texturing operation with the texturizing device, the wire
brush 168. The brush 168 can be brought into contact with the
respective shoulders 956 of the tire casing 950 with the rasp
pedestal 112 moving toward the respective shoulder of the tire
casings along a predetermined line of movement 960, such as along a
line substantially perpendicular to the face of the shoulder. The
rasp pedestal 112 can so move until the control unit detects that
the actual current draw of the rasp drive motor reaches a
predetermined value, such as 120% of a no-load current draw of the
rasp drive motor, for example, whereupon the rasp pedestal 112 can
stop moving toward the tire casing 950. The wire brush 168 can act
upon each shoulder 956 for a predetermined length of time, ten
seconds, for example, to provide a desired texture surface for the
shoulders, such as an RMA value of about 2, for example.
[0138] In other embodiments, the control unit can position the rasp
pedestal for texturing the shoulders by monitoring another
parameter, such as, the temperature at the surface of the shoulder
of the tire casing, the force applied between the rasp pedestal and
the tire casing, the actual current draw of the tire drive motor,
or the current draw of the moving assembly, for example, and
placing the pedestal in a position where the monitored parameter
has a predetermined value.
[0139] The tire buffer 100 of the present invention can allow for
tire buffing operations to occur at a more efficient rate than
prior automated systems. For example, tire buffing tests conducted
with the model 8200 tire buffer manufactured by Bandag, Inc. have
shown that a typical tire buffing cycle requires 2.5 minutes,
yielding about 20 buffed tires per hour. In tests conducted with
the tire buffer of the present invention, a typical tire buffing
cycle requires only 2 minutes, yielding about 25 tires per hour.
Furthermore, the automated features of the tire buffer of the
present invention allow an operator to operate another machine, and
possibly two other machines, while operating the tire buffer,
thereby improving the productivity of each operator. For example,
in a typical 2 minute tire buffing cycle with the tire buffer, an
operator can devote 20 seconds of the 120 second period to loading
and unloading the tire buffer, leaving 100 seconds to devote to
another machine or machines.
[0140] All references, including publications, patent applications,
and patents, cited herein are hereby incorporated by reference to
the same extent as if each reference were individually and
specifically indicated to be incorporated by reference and were set
forth in its entirety herein.
[0141] The use of the terms "a" and "an" and "the" and similar
referents in the context of describing the invention (especially in
the context of the following claims) are to be construed to cover
both the singular and the plural, unless otherwise indicated herein
or clearly contradicted by context. Recitation of ranges of values
herein are merely intended to serve as a shorthand method of
referring individually to each separate value falling within the
range, unless otherwise indicated herein, and each separate value
is incorporated into the specification as if it were individually
recited herein. All methods described herein can be performed in
any suitable order unless otherwise indicated herein or otherwise
clearly contradicted by context. The use of any and all examples,
or exemplary language (e.g., "such as") provided herein, is
intended merely to better illuminate the invention and does not
pose a limitation on the scope of the invention unless otherwise
indicated.
[0142] While the invention is described herein in connection with
certain preferred embodiments, there is no intent to limit the
present invention to those embodiments. On the contrary, it is
recognized that various changes and modifications to the described
embodiments will be apparent to those skilled in the art upon
reading the foregoing description, and that such changes and
modifications may be made without departing from the spirit and
scope of the present invention. The inventors expect skilled
artisans to employ such variations as appropriate, and the
inventors intend for the invention to be practiced otherwise than
as specifically described herein. Accordingly, the intent is to
cover all alternatives, modifications, and equivalents included
within the spirit and scope of the invention. Moreover, any
combination of the above-described elements in all possible
variations thereof is encompassed by the invention unless otherwise
indicated herein or otherwise clearly contradicted by context.
* * * * *