Note: Descriptions are shown in the official language in which they were submitted.
CA 02427780 2003-05-02
BI~CKC,It'oUI~~D
Z. Field of the Tnvention
The present invention relates to systems and methods for milling paving
material.
More particularly, the present invention relates to systems and methods that
provide
I O increased stability, support and power while grinding paving material.
3. Background of the Invention and Related Art
Asphalt milling is a technique currently employed 'to remove asphalt pavement
for
reconstruction or ,resurfacing; and for accessing buried utility lines. The
technique
IS involves the reiizoval of asphalt pavement thxough the use of a cold
planer, which can
remove up to approximately two inches of pavement surface during a particular
pass.
A cold planer typically includes a barrel-like attachment, referred to as a
mandrel,
and a variety of bits (e.g., 40) that are affixed to the e;aerior surface of
the mandrel.
Coupled to the cold planer is a vehicle (e.g., a bobcat or s:l~id-steer) that
is used to propel
20 the cold planer. The mandrel rotates and is pushed into the pavement by the
hydraulic
system of the vehicle, causing the bits to grind up the asphalt pavement. The
vehicle
Page 2 -
CA 02427780 2003-05-02
pushes the cold planer as the mandrel rotates to grind a trench in the asphalt
pavement
that is typically up to 24 inches wide.
While this technique enables the creation of a trench that is up to 2 inches
deep,
various problems exist. For example, traditional cold planers stall out upon
attempting to
grind 2 - 3 inches of asphalt pavement. Thus, when desiring to ;hill a depth
of 6 inches
of pavement, at least three passes of the cold planer must be conducted.
Furthermore, the
milled asphalt composite left behind in the wake of the cold planer must be
removed
between each pass. As a result, this process has proven to be bane consuming.
The process is further delayed by the requirement Of 11aV1Ilg to push the cold
planer at an extremely slow rate. Much of the power from the skid-steer is
used to rotate
the mandrel. As such, limited power is available to push the cold planer
forward.
Typically, the cold planer creates a trench by grinding the pavement at a rate
of up to %z
mph.
The process is further hampered by instability. The vehicle used to propel the
cold planer typically loses traction and has a tendency to shake. A loss in
pressure
between the actions of providing pressure on the cold planer and lowering the
mandrel
also yields to instability. Moreover, a procedure of edge milling typically
requires the
removal of supporting structures of the cold planer, triggering further
instability.
Thus, while the traditional technique of asphalt milling enables the creation
of a
milled trench that is up to 2 inches deep, the technique has proven to be
instable and time
consuming. Accordingly, it would be an improvement in the art to augment or
even
replace existing techniques to enable a trench to be milled in asphalt
pavement at a
quicker rate andlor to provide increased stability to the milling process.
- Page ~ -
CA 02427780 2003-05-02
SUMMARY AND OBJETS OF THE INVENTION
The present invention relates to systems and methods for milling paving
material.
More particularly, the present invention relates to systems and methods that
provide
increased stability, support and power while gnndmg paving material.
Tmplementation of the present invention takes place in association with a self
powered milling system for use in milling or grinding asphalt and is
configured for
coupling to a vehicle (e.g., a bobcat, steer-skid, or other vehicle) that
selectively pushes
or pulls the milling system in a desired direction. The milling system
includes a
cylindrical mandrel, having a variety of bits attached thereon, which spins on
an axis to
' break up and mill the asphalt. The mandrel is powered by a milling system
motor that
speeds up production and enables milling of very thick asphalt (e.g., 8 inch
thick asphalt)
in a single pass. A breaker bar of the milling system is continuously located
at or near
ground level during the milling process to hold the asphalt down as it tries
to lift up
'''', during the process. The breaker bar further assists in breaking up the
milled asphalt
aggregate.
In one implementation, the milling system includes a carriage that follows the
contour of the ground. The carriage provides stability during the milling
process,
allowing only the mandrel or cutting head to move during the process. The
carriage may
be selectively adjusted to provide cuts at various angles. Furthermore, the
carriage is
designed to include a flush side to enable use of the milling system in
perfornZing precise
edge milling of the asphalt.
While the methods and processes of the present t:nvention have proven to be
particularly useful in providing increased stability, support and power in the
area of
-Fage4-
CA 02427780 2003-05-02
milling asphalt, those skilled in the art shall appreciate that the methods
and processes
Call be used to mill a variety of different surfaces.
These and other features and advantages of the present invention will be set
forth
or will become more fully apparent in the description that: follows and in the
appended
claims. The features and advantages may be realized a~:ld obtained by means of
the
instruments and combinations particularly pointed out in the appended claims.
Furthermore, the features and advantages of the invention rnay be learned by
tl~e practice
of the invention or will be obvious from the description, as set fOI-th
hereinafter.
-PageS-
CA 02427780 2003-05-02
BRIEF ~GSCR1P'~'IO1V ~F T'HE ~RA'4'1'iI~GS
In order that the manner in which the above-recited and other advantages and
features of the invention are obtained, a more particular description of the
invention
briefly described above will be rendered by reference to specific embodiments
thereof,
which are illustrated in the appended drawings. Understanding that these
drawings depict
only typical embodiments of the invention and are not therefore to be
considered limiting
of its scope, the invention will be described and explained v~ith additional
specificity and
detail through the use of the accompanying drawings in which:
Figure 1 illustrates a perspective view of a representative embodiment of the
present invention;
Figure 2 illustrates, a front view of the embodiment of Figure l;
Figure 3 illustrates a perspective view of a representative cutting head that
may be
used in association with the embodiment of Figure l;
Figure 4 illustrates a side view of the embodiment o:f Figurf° l ; and
Figure 5 illustrates atop view of the embodiment of Figure 1.
- Page 6 -
CA 02427780 2003-05-02
DETAILED DESC'RTPTION OF TdIE PREFERRED 1;M130D1n'IENTS
It will be readily understood that the components of the present invention, as
generally described and illustrated in tlae f gures herein, could be arranged
and designed
in a wide variety of different configurations. Thus, the following more
detailed
S description of the embodiments of the system and method of the present
invention, and
represented in Figures 1 through 5, is not intended to limit the scope of the
invention, as
claimed, but is merely representative of the presently preferred embodiments
of the
invention.
The presently preferred embodiments of the invention will be best understood
by
reference to the drawings wherein like parts are designated by like numerals
throughout.
The present invention relates to systems and methods for milling paving
material.
More particularly, the present invention relates to systems and methods that
provide
,_ increased stability, support and power while grinding paving material.
W the disclosure and in the claims the term "paving material" shall refer to
any
material that may be used to pave a road, path, sidewalk, parking lot,
driveway,
thoroughfare, or any other similar surface. Examples of paving materials
include asphalt,
tarmac, pavement, cement, clay, stone and dirt.
Embodiments of the present invention take place in association with a self
powered milling system for use in milling or grinding paving material, and
which may be
configured to be coupled to a vehicle (e.g., a bobcat, steer-skid, back hoe,
excavator or
other vehicle) that selectively pushes or pulls the self powered milling
system in a
desired direction. The milling system includes a cutting head, such as a
cylindrical
mandrel that includes a variety of bits attached thereon. The mandrel spins on
an axis to
-Page7-
CA 02427780 2003-05-02
break up and mill the paving material, and is powered by a milling system
motor that
speeds up production and enables the milling of very thick paving material
(e.g., 8 Inch
thick asphalt) in a single pass.
Embodiments of the present invention further embrace a zr~illing system having
a
carriage that follows the contour of the ground. The carriage provides
stability dozing the
milling process, allowing only the cutting head to move during the process,
and may be
selectively adjusted to provide cuts at various angles. In a fuz-ther
embodiment, the
carriage includes a flush side to enable perfomlance of precise edge milling.
In one embodiment, a breaker bar is coupled to the carriage. The breaker bar
is
continuously located at or near ground level to 1-IOId the asphalt down as it
tries to lift up
during the IllIlllllg process. The breaker bar is further employed to assist
in the breaking
up the milled asphalt aggregate.
As provided above, embodiments of the presel~It invention take place in
association with a self powered milling system that may be used to n .ill or
grind paving
I5 material, and that may be configured to be coupled to a vehicle (e.~;., a
bobcat, steer-skid,
back hoe, excavator or other vehicle), which selectively pushes or pulls the
self powered
milling system in a desired direction. With reference to Figure I, a
representative
embodiment of a self powered milling system is illustrated as milling system
I0, which
includes cutting head 12 having bits 14 attached thereon, motor I5, carriage
18, wheels
20, and vehicle coupler 22.
In Figure 1, milling system IO is configured to be coupled to a vehicle using
vehicle coupler 22. . In the illustrated embodiment, vehicle coupler 22 is
adjustable to
allow for a coupling of milling system 10 to any type of vehicle. ~nce coupled
to milling
-Page8..
CA 02427780 2003-05-02
system 10, the vehicle (not shown) may be operated by a user to selectively
push or pull
milling system 10 in a particular direction.
Milling system 10 comprises a motor 16, v~~hich is separate from the motor of
the
vehicle. As such, milling system 10 is self powered to enable the grinding or
milling of
paving material. More specifically, motor 16 is dedicated to the acl:uating of
cutting head
12 in order to grind or mill paving material under milling system 10.,
The use of cutting head 12 is more fully illustrated in Figures 2 and 3. hi
Figure
2, a front view of anilling system 10 is provided. Cutting head 12. is
actuated by motor 16
and spins on an axis. As cutting head 12 is spinning, milling system 10 is
pushed by a
vehicle coupled thereto and mills paving material that passes unden~eath
cuttirig head 12.
With reference now to Figure 3, a perspective view of cutting head 12 is
illustrated. In Figure 3, cutting head 12 is a barrel-like attachment, known
as a mandrel.
The mandrel spins and is pushed into the paving material. Bits 14 affixed to
the exterior
of the mandrel engage and grind up the asphalt. Once ground, the asphalt array
be easily
removed and replaced.
In one embodiment, approximately forty bits are located on the exterior
surface of
cutting head 12. The bits 14 are scattered and patterned along the anandrel in
a way that
optimally enables pulverization and are exposed to the asphalt when the
mandrel is in
operation. In addition to the bits on the exterior of the mandrel, six bits
are located at
each end of the mandrel. The end bits prevent the mandrel from wedging into
the paving
material and from becoming stuck, and are known as "inside end bits."
Each bit 14 has a hardened or carbide tipped end, a stem, and a flat end at
the
bottom of the stem. The bits 14 are attached to a mandrel by their insertion
into chamlels
Page 9
CA 02427780 2003-05-02
or blocks of the mandrel. In one embodiment, the stem of a bit 14 has a spring
collet
surrounding it. When the bit is forced into a channel of a bit block and
pressed do4vn
through the shaft, the spring collet squeezes against the stern to tightly fit
the stem within
the channel. An aru~ular space on the bit that engages a Tipped section of the
top end of
the bit shaft and locks the bit into the shaft is located between the bit stem
and the tipped
end of the bit. This annular space prevents the tip from leaving the shaft.
A bit 14 may be removed, such as when it has become tipped out, by pounding on
the exposed flat end of a bit 14 seated within the shaft, and drive the bit 14
from the shaft.
The bit is removable because despite its secure fit within the shaft, when the
flat end is
impacted, the spring collet is forced inward to contract and pass by the Iip
of the shaft and
is released from the annular space within the bit block.
Unfortunately, due to wear and tear, bits require' replacement. For example,
when an operator of milling system 10 hits a manhole, bits nay become tipped
out and
need replacement. The need far replacing bits 14 arises frequently, therefore
time
1 S efficient and cost effective techniques for replacing bits is greatly
desired.
In the illustrated embodiment, and with reference back to Fif;ure l, a bit
access is
provided to facilitate bit removal from a top-level or a top portion of
milling apparatus
10. The bit access is illustrated as removable cover 30, which is hinged to a
casing that
covers cutting head 12. 11z another embodiment, removable cover 30 is
mechanically
removable. Cover 30 provides access to bits 14 and facilitates access by
eliminating the
traditional requirement of having to access bits 14 from underneath a cold
planer.
In the illustrated embodiment, removable cover 30 removes a top portion fi~om
a
casing that covers cutting head 12 as well as a portion of either side of the
casing. As
- Page 10 -
CA 02427780 2003-05-02
such, in one embodiment, the top 60° to 90° of the cutter head
12 is exposed when
removing removable cover 30. Since a portion on each of the sides of the
casing is
removable, access to the inside end bits is facilitated.
The use of motor 16 to drive cutting head 12 eliminates the need of
traditional
practices to steal power from the vehicle motor (not shown). The use of motor
1b
exponentially speeds up production (it is approximately 4 - 6 times faster
than traditional
methods) since it enables the vehicle motor to be dedicated to moving system
10 and
further enables up to approximately S inches of paving material to be milled
in a single
pass, as opposed to 2 inches by traditional methods. . As such, the time
required for an
operator to perform the milling of paving material is greatly reduced since up
to 8 inches
can be milled with each pass.
Thus, for example, a traditional cold planer that claims it can mill up to 6
inches
deep actually.requires three separate passes, where each pass mills 2 inches
of the paving
'. material, in order to mill the total 6 1I1C1-z deep paving matezzal.
Furthermore, a traditional
' , milling head requires approximately 72 hp to run effectively. An average
skid-steer
motor doesn't generally produce more than 72 hp, winch must be used to spin
the milling
head and to push the cold planer. Therefore, since so much of the power is
required to
spin the milling head, the amount of power available to push the cold planer
is limited
and results in an extremely slov~r process. Typically, the traditional cold
planer is only
able to mill up to about 2 inches deep and is only pushed at'/z mph.
In contrast, in accordance with the present invention, power (e.g., 72 hp or
another amount of power) from the vehicle motor is provided to selectively
movelpush
the milling system 10, and an additional amount of power (e.g., another 72 hp
or another
Page 11 -
CA 02427780 2003-05-02
amount) is provided to spin the cutting head 12. The increased power yields
increased
efficiency in perfornling a milling job.
Embodiments of tile present invention further increase the ability to mill
paving
material by providing a belt-driven system to power a cutting head.
Traditionally,
vehicles used to power a traditiozlal cold planer are powered through the
utilization of a
hydraulic system, which yields a high efficiency loss. For example, a
hydraulic system is
typically about 60% efficient. Thus in the example above, where in a
traditional
procedure 72 lip is available to both move a traditional cold planer' and to
spin a cutting
head, the actual, power, available due to the hydraulic system is 43.f. hp (72
hp multiplied
by 60% efficiency is 43.2 hp). The other 28.8 hp is lost in heat.
In contrast, embodiments of the present invention embrace the use of a belt-
driven
system 34, which provides 90% to 95% effzciency. Thus, where motor 16 provides
72
hp, milling system IO is actually placing 64.8 (72 hp multiplied by 90%
efficiency is 64.8
hp) on spinning cutting head 12. The belt-driven system 34 is additionally
illustrated in
Figures 4 and 5, which are respectively a top view and a side view of milling
system 10, .
and includes a belt and a transmission 64 (Figure 5). The belt couples shaft
42 (Figure 3)
of cutting head 12 with motor 16 to cause motor 16 to rotate shaft 42 and
cause cutting
head 12 to spin.
In one embodiment, system 10 further includes a belt tensioning system 60
(Figure 5), such as an automatic or manual tensioner, that keeps the belt of
the belt-driven
system taut. In a further embodiment, the belt-tensioning system 60 includes a
pneumatic
air cylinder 62 (Figure 5). As such, the belt may be set and , aligned with
low to no
tension and locked into place. The belt-tensioning system 60 ma;y then be
engaged to
- Page 12
CA 02427780 2003-05-02
apply tension to the belt in order to keep the belt taut. In one embodiment,
the tension
automatically adjusts to pressure. Therefore, when the system IO hits, for
example, an
object while in use, the belts are autolnaticalIy kept taut.
With reference back to Figure 1, milling system 10 provides a carriage l8,
which
sits near the ground and provides support. In one embodiment, carriage I8 sits
approximately one-half inch above the ground. In tOe illustrated embodiment,
wheels 20
are coupled to carriage I8. Carriage 18 provides pressure on cutting head 12.
Carriage I8 includes a flush side 26 that enables edge milling of paving
material.
For example, when milting system 10 is used to mill paving material that is
located up
against a vertical surface, milling system 10 is pushed along the v'erticaI
surface with the
flush side 26 near the vertical surface. As such, the paving material may be
milled within
three to four inches of a vertical surface without touching the sides of
milling system 10.
The remaining portion of paving material may then be knocked off with a
shovel. In
contrast, traditional techniques required disassembly of a cold planer, wh lch
has caused
instability In using the cold planer. The use of carriage 18 further allows
for carriage 18
to potentially bump the vertical surface rather than cutting head I2, which
would damage
the vertical surface.
Carriage 18 is configured to be selectively adjusted to enable milling system
10 to
be used in such a way as to cut on a particular angle or taper. Embodiments of
the
present invention embrace the ability to manually or hydraulically adjust the
height of
wheels 20. Milling system IO maintains traction and support by aIowing
carriage 18 to
follow the ground while cutting head 12 follows the set angle. Irl contrast,
traction is lost
in traditional techniques.
- Page 13 -
CA 02427780 2003-05-02
Milling system 10 may be manually or hydraulically tipped through the use of a
cylinder, such as cylinder 28. For example, cylinder 28 is locked for safety
reasons while
moVIIlg milling system 1 ~. Once milling System 10 15 In use, cylinder 28,
which allows
cutting head 12 to raise and lower, may be manually or hydraulically actuated
to allow
S cutting head 12 to move back and forth. IIl other words, cutting head 12 is
allowed to
float, which allows equal traction for the vehicle Lised. While milling,
cutting head 12 is
allowed to adjust to whatever angle it needs to in order to adjust and follow
the contour
of the ground. As such, mufti-vector positioning of cutting lead 12 is made
possible.
Embodiments of the present invention embrace an improved method for entering
1~0 the ground in order to mill paving material. In one embodiment, the
vehicle is locked up
in a home position and the anus of the vehicle are locked down with the tilt
locked back.
In this manlier, nothing shakes or vibrates. Pressure is provided onto cutting
head 12 by
cylinder 28, and motor 16 engages cutting head 12 to allow for the milling to
occur. As
such, embodiments of the present invention may be dropped into any asphalt or
paving
1S material and pulverize the paving material into a fine gravel.., similar to
a road base.
Thus, a first cylinder, illustrated as cylinder 28, holds cutting head 12 down
into
the ground, pulling between carriage 18 and cutting head I2. A second cylinder
controls
the tilt that is enabled by milling system 10 and has the extra option of
allowing cutting
head 12 to float while in use to enable a more effective milling. In one
embodiment, as
20 illustrated in Figure 4, systenl 10 pivots about pivot point 52. A third
cylinder is utilized
to shift the vehicle hook-up.
With reference back to Figure l, a bearing 32 faces outward and is protected
from
any debris, such as rocks, that may be spinning around. :Ln one embodiment, a
mound
- Page l~ -
CA 02427780 2003-05-02
sets bearing 32 inside cutting head 12, but facing out to provide access to
grease bearing
32. Alternatively, a user may pop bearing 32 out and remove it without
disassembling
any other portion of milling system 10. Alternatively, the cutting head 12 may
be
dropped out from system 10 and replaced with another cutting head. Thus,
bearing 32 is
placed inside the cutting head 12, facing out where it is still protected.
Also inside cutting head 12 is a well mount or a gear reduction planetary that
is
mounted to one side of the drum and to the frame. On the other side of the
drum an
outboard shaft is mounted with an outboard bearing support to help the cutting
head ride.
This increases the life span of the gearbox and virtually provides an
unlimited life span of
the gear reduction planetary.
In a further embodiment, a remote control system is utilized to pi~ovide
control of
the various cylinders in order to guide or steer milling system I0. In one
embodiment,
the remote control system utilizes a radio control system, such as an RF
frequency, to
provide the control. The system has an E-stop with a continuous transmission.
If an
operator gets far enough away from milling system 10, the system shuts doom
automatically.
3n a further embodiment, milling system 10 includes an extended drive input.,
A
shaft with a flex coupling that includes a couple of bearings that have two
pilot tubes that
bolt up to cutting head 12 and support the belt enable the engine to be flush
on side 26
rather than having to overhang approximately 12 inches.
Embodiments in the present invention further embrace a large frame that holds
still, just allowing the cutter head to move up and down. >1Z other words, the
vehicle
frame is extended 10 feet or longer by the use of the carriage of the milling
system.
- Page I 5 -
CA 02427780 2003-05-02
Furthermore, a breaker bar illustrated as breaker bar 24, is continuously
located at ground
level to hold the pavement down as it tries to lift up and is used to help
break up the
aggregate that has been milled.
Thus, as discussed herein, the embodiments of the present invention embrace
systems and methods that provide increased stability, support and power in
milling
paving material. The present invention may be embodied in other specific
fornls without
departing from its spirit of essential characteristics. The described
embodiments are to be
considered in all respects only al illustrative and not restrictive. The scope
of the
invention is, therefore, indicated by the appended claims, rather than by the
foregoing
description. All changes which come within the meaning and range of
equivalency of the
claims are to be embraced within their scope.
Page 16 -
