U.S. patent application number 12/140881 was filed with the patent office on 2009-12-17 for durable, coated snow plow blades and method of forming a coated snow plow blade.
Invention is credited to Mark D. Buckbee, Terry C. Wendorff.
Application Number | 20090307934 12/140881 |
Document ID | / |
Family ID | 41413434 |
Filed Date | 2009-12-17 |
United States Patent
Application |
20090307934 |
Kind Code |
A1 |
Wendorff; Terry C. ; et
al. |
December 17, 2009 |
DURABLE, COATED SNOW PLOW BLADES AND METHOD OF FORMING A COATED
SNOW PLOW BLADE
Abstract
A snow plow blade is provided including a support frame and a
moldboard. The moldboard is constructed of a metal material
preferably painted with a paint including a polyurethane binding
agent. The moldboard surface is contacted with a 100% solids
polyurethane component providing an abrasion resistant, non-stick
coating chemically bonded to the contacted surfaces of the snow
plow blade.
Inventors: |
Wendorff; Terry C.;
(Slinger, WI) ; Buckbee; Mark D.; (Wauwatosa,
WI) |
Correspondence
Address: |
REINHART BOERNER VAN DEUREN S.C.;ATTN: LINDA KASULKE, DOCKET COORDINATOR
1000 NORTH WATER STREET, SUITE 2100
MILWAUKEE
WI
53202
US
|
Family ID: |
41413434 |
Appl. No.: |
12/140881 |
Filed: |
June 17, 2008 |
Current U.S.
Class: |
37/197 ;
37/266 |
Current CPC
Class: |
C09D 5/00 20130101; E01H
5/06 20130101 |
Class at
Publication: |
37/197 ;
37/266 |
International
Class: |
E01H 5/00 20060101
E01H005/00 |
Claims
1. A method of forming an abrasion resistant snow plow blade
comprising: providing a snow plow blade including a metal support
frame and a metal moldboard having a plowing surface; preparing the
plowing surfaces of the moldboard and the support frame for
painting; applying a paint layer to the plowing surfaces of the
moldboard and frame, the paint layer including a polyurethane
binding component; allowing the paint to one of dry or cure;
contacting the painted plowing surfaces of the moldboard and frame
with a substantially 100 percent solids polyurethane polymer
system; and curing the polyurethane system, wherein the 100% solids
polyurethane component chemically interacts and bonds to the paint
layer on the painted plowing surfaces of the moldboard and
frame.
2. The method of claim 1, wherein the moldboard is construction of
at least one of steel and aluminum.
3. The method of claim 1, wherein preparing the plowing surface for
painting includes at least one of cleaning, sanding, priming and
chemically treating the plowing surface.
4. The method of claim 1, wherein the paint layer includes at least
one of an alkyd, acrylic, epoxy, silicone, polyester and vinyl
binding component.
5. The method of claim 1, wherein the contacting step includes
coating the plowing surface with the substantially 100 percent
solids polyurethane system, without pretreating the plowing
surface.
6. The method of claim 1, wherein the substantially 100 percent
solids polyurethane system includes a 100 percent solids aromatic
polyurethane system, a 100 percent solids aliphatic polyurethane
system and combinations thereof.
7. A method of forming a reinforced snow plow blade having a plow
surface with a low co-efficient of friction, the method comprising:
providing a snow plow support frame having a front portion; forming
a moldboard from a metal substrate, the moldboard having a forward
face, a rear face, a top edge, a bottom edge and opposing side
edges, the moldboard having a an arcuate cross-sectional shape;
cleaning the moldboard; applying a paint layer to the forward face,
the rear face, the top edge, the bottom edge and each opposing side
edge of the moldboard, the paint layer including at least one
binding component, the binding component comprising polyurethane;
contacting the untreated and mechanically undisturbed paint layer
on at least one of the front face, the top edge, the bottom edge
and each opposing side edge of the moldboard with a 100 percent
solids elastomeric polymer system; curing the polymer system,
wherein the 100 percent solids elastomeric polymer system
chemically interacts and forms a molecular bond with at least one
component of the paint layer; and securing the moldboard to the
front portion of the support frame.
8. The method of claim 7, wherein the moldboard is constructed of a
steel material.
9. The method of claim 7, wherein applying the paint layer includes
allowing the paint layer to dry.
10. The method of claim 7, wherein the paint layer also includes at
least one of an alkyd, acrylic, epoxy, silicone, polyester and
vinyl binding component.
11. The method of claim 7, wherein the contacting step includes
contacting the untreated and mechanically undisturbed paint layer
before it is dry.
12. The method of claim 7, wherein the 100 percent solids
elastomeric polymer system is a polyurethane-based system.
13. The method of claim 12, wherein the 100 percent solids
polyurethane system includes a 100 percent solids aromatic
polyurethane system, a 100 percent solids aliphatic polyurethane
system and combinations thereof.
14. A method of repairing a painted metal snow plow blade including
a support frame and a moldboard, the method comprising: removing
the moldboard from the frame; applying a paint layer over a crack
or chip on the moldboard, the paint layer including a polyurethane
resin; contacting the untreated and mechanically undisturbed paint
layer with a 100 percent solids polyurethane system; curing the
polymer system, wherein the 100 percent solids polyurethane system
chemically interacts and forms a molecular bond with at least one
component of the paint layer; and resecuring the moldboard to the
front portion of the support frame.
15. The method of claim 14, wherein the 100 percent solids
polyurethane system includes a 100 percent solids aromatic
polyurethane system, a 100 percent solids aliphatic polyurethane
system and combinations thereof.
16. In combination with a snow plow blade comprised of a snow plow
support frame, a reinforced snow plow moldboard comprising: a metal
substrate having a forward face, a rear face, a top edge, a bottom
edge and opposing side edges, the substrate also having a generally
arcuate cross-sectional shape providing a plowing surface; a paint
layer applied to the forward face, the rear face, the top edge, the
bottom edge and each opposing side edge of the moldboard, the paint
layer including a polyurethane resin; and a 100 percent solids
polyurethane system contacting and molecularly bound to the paint
layer.
17. The moldboard of claim 16, wherein the paint layer also
includes at least one of an alkyd, acrylic, epoxy, silicone,
polyester and vinyl binding component.
18. The moldboard of claim 16, wherein the 100 percent solids
polyurethane system includes a 100 percent solids aromatic
polyurethane system, a 100 percent solids aliphatic polyurethane
system and combinations thereof.
19. A durable, low friction snow plow blade, the snow plow blade
comprising: a support frame having a front plowing face and a rear
face configured to mount to a snow plow vehicle, a moldboard
constructed at least in part of a metal material, the moldboard
having a front plowing surface, a rear surface secured to the front
face of the frame, a top edge, a bottom edge and opposing side
edges, the moldboard having a generally arcuate cross-sectional
shape; a paint layer applied to the plowing surface of the
moldboard, the paint layer including a polyurethane resin
containing at least one functionally reactive substituent group;
and a 100 percent solids polyurethane system contacting and
molecularly bound to the at least one functionally reactive
substituent group of the paint layer.
20. The snow plow blade of claim 16, wherein the moldboard is
constructed of a steel material.
21. The snow plow blade of claim 16, wherein the paint layer also
includes at least one of an alkyd, acrylic, epoxy, silicone,
polyester and vinyl binding component.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to snow plows and more
particularly to snow plow blades treated with a durable, non-stick
composition and a method for treating snow plow blades with such a
coating.
[0003] To move and remove snow and other road debris, a snow plow
must be designed to withstand vibration, debris and heavy snow
impact, exposure to salt and UV radiation and other rugged
environmental conditions over its operating lifetime. Snow plow
vehicles depend on the particular plowing application, and can
include medium or light duty trucks, a skid or front-end loaders or
commercial/government vehicles. A snow plow blade is mounted to the
front of the plowing vehicle and has a generally curvilinear shape,
to roll the snow upwardly from the bottom and then move it
transversely across the face of the blade.
[0004] Snow plow blades come in may different types and sizes,
depending on the particular plowing application. Snow plow designs
can include straight blade, which are single blade designs, or
articulated or V-plow blade designs, where the snow plow includes a
center plow portion and a snow plow blade or wing extending from
each, opposite side of the center portion. In addition, snow plows
can also include straight blade and/or articulated blade designs
with end extensions, front wearstrips, rear scrapers or top
deflectors.
[0005] In its simplest form, a snow plow blade includes a support
frame, having a substantially arcuate or curved overall
cross-section, and a skin or moldboard, also having an arcuate
cross-section. The rear side of the snow plow blade is hitched or
otherwise attached to the plowing vehicle. The moldboard is secured
to the front of the frame and includes a front surface that
directly contacts and moves the snow during operation of the snow
plow. A wearstrip can also be secured to the front side of the
frame near the bottom edge of the moldboard.
[0006] In many applications, snow plow moldboards are constructed
of steel, aluminum or another lightweight metal, alloy or composite
material capable of withstanding the wear conditions usually
encountered when plowing. It is intended that during operation of
the snow plow, snow is thrown and/or rolled forward across the
front face of the snow plow blade and away from the road, and the
snow plow vehicle. However, ice and snow can build-up and stick to
the moldboard of the snow plow blade, preventing the blade from
moving the maximum amount of snow possible, lowering the efficiency
of the snow plow.
[0007] In addition, when the blade hits an object in the road, a
curb or a heavy pile of snow, the front face of the moldboard
receives the majority of force of the impact. As such, the
moldboard is subject to denting, cracking and failure over time,
requiring replacement thereof.
[0008] Over the years, there have been several attempts to improve
the efficiency and plowing capacity of snow plows while also
maximizing the strength and durability of the snow plow blade. For
example, one approach is to modify the radius of curvature or
surface texture of the moldboard and frame to improve snow
deflection. Another approach includes add-on components, such as
snow deflectors or wipers to the snow plow to improve
efficiency.
[0009] Another approach can include lowering the coefficient of
friction on the face of the moldboard to minimize ice and wet snow
build-up. For example, wax or silicone coatings have been used by
snow plow operators to reduce friction on the surface of the
moldboard. However, these coatings require substantial cleaning of
the snow plow blade and preparation of the snow plow blade surface,
such as mechanically roughening up, sanding or priming the surface
of the blade, in order for the coating to adhere to the blade. In
addition, these coatings simply cover the surface of the moldboard
and therefore easily chip and peel off the blade when the blade is
struck by rocks, stones and other debris from the roadway, which
impact the moldboard under significant forces. Moreover, these
coatings may temporarily improve snow rolling characteristics of
the moldboard, but they do not add strength or abrasion resistance
to the moldboard.
SUMMARY OF THE INVENTION
[0010] The disadvantages and limitations of the background art
discussed above are overcome by the forming an impact resistant
snow plow blade having a low coefficient of friction plowing
surface, and a snow plow blade formed by said method is
provided.
[0011] A typical snow plow blade comprises a support frame and a
substantially arcuate moldboard or snow plow skin secured to the
front of the frame. In some snow plow designs, the snow plow blade
also includes a wearstrip secured to the front of the support frame
near the bottom of the moldboard, and a rear scraper secured to the
rear of the support frame. Depending on the type of plowing
application, a snow plow blade, and the corresponding frame and
moldboard, can be formed in a variety of lengths and heights. It
will be appreciated that the present invention is applicable to all
plowing applications, including plow blades formed for light duty
or medium trucks, commercial vehicles, and/or small skid
loaders.
[0012] A typical moldboard has a curved or arcuate shape to enhance
the snow rolling characteristics thereof. According to the
teachings of the present invention, the moldboard is preferably
constructed of a metal material, such as steel. The material of
construction can include cold rolled steel, stainless steel, carbon
steel or another steel composite or alloy material. Further, other
lightweight metals, alloys or composite materials can be used, such
as those including aluminum or tungsten. It will be appreciated
that the methods of the present invention can be used with
moldboards constructed of thermoplastic material, such as
polycarbonate, if desired.
[0013] In a first step, a snow plow blade, including a support
frame and a moldboard is provided in the desired shape and size,
and preferably with the desired apertures and/or fittings so that
the moldboard and/or wearstrip can be secured to the frame. In
certain preferred applications of the present invention, the
moldboard is welded to the fame members, for added strength and
durably of the snow plow blade. As described above, preferably, the
moldboard is constructed of a metal material.
[0014] Next, the moldboard, and the frame if provided together, are
prepared for painting. In particular, the moldboard and frame
surfaces can be cleaned with alcohol, solvent or surfactant to
remove any oil, grease, dust and/or dirt present on each of the
surfaces. In some instances, and depending on the type of paint
selected, the moldboard and frame surfaces can also be grinded or
sanded to mechanically dull or rough up the metal surfaces and to
remove any rust. Other steps that may be taken to prepare the
moldboard and frame surfaces for painting can include applying one
or more primers, UW treating or chemically treating the surfaces of
the moldboard. It is appreciated that the metal moldboard is
preferably prepared for painting in accordance with recommendations
by the paint manufacturer.
[0015] The frame and moldboard are then painted with a paint
including a polyurethane resin as at least one of its binding
components. The polyurethane resin is formed, as known in the art,
by reaction of an active hydrogen containing compound, such as a
polyol, with a diisocyanate or polymeric isocyanate component, in
the presence of a catalyst, wherein a sufficient amount of
crosslinking occurs between isocyanate groups (--NCO) and the
polyol's hydroxyl end-groups (--OH). In polyurethane based paint
systems, the resulting polyurethane polymer component is dispersed
in an aqueous solution or other solvent of the paint system. When
the paint dries or is otherwise cured, a thin film or layer of
paint, is present on the surfaces of the moldboard. Consistent with
the broader aspects of the present invention, the paint applied to
the moldboard surfaces need not be completely dry or cured prior to
the coating step.
[0016] In a treating or coating step, the plowing surfaces of the
moldboard contacted with a 100% solids elastomeric polyurethane
system. The support frame plowing surfaces can also be coated with
the 100% solids elastomeric polyurethane system, if desired. The
rigidity of the layer of polyurethane material coated on to the
surfaces of the moldboard and frame depend on the degree of
crosslinking of system, and can be a matter of design choice and
end-use application. The 100% solids polyurethane system utilized
in the present invention is substantially solventless, fast curing,
pigment compatible, abrasion and impact resistant, and corrosion
and UW resistant.
[0017] The 100% solids polyurethane coating system is applied
directly to the painted moldboard and frame surfaces. Importantly,
the surfaces of the moldboard that are contacted with the 100%
solids polyurethane coating require no surface preparation or
treatment prior to application. In particular, the methods of the
present invention do not require priming, sanding, chemically
treating or otherwise pre-treating or preparing the application
surfaces of the moldboard and frame. As such, the method of the
present invention saves time and expense while also providing the
friction-reduced, impact resistant moldboard of the present
invention. The methods of the present invention also reduces
operator exposure to unnecessary procedures, such as priming, and
hazardous chemical materials.
[0018] The polyurethane protective coating is cured to form a
substantially smooth or level surface having a lower co-efficient
of friction than both the bare metal surfaces of the moldboard and
frame and the painted surfaces of the moldboard and frame. Without
limitation to any particular theory or mode of operation, the 100%
solids polyurethane coating material is chemically bonded to at
least one functional group or component present in the previously
applied paint layer. As such, the excellent adhesion of the 100%
solids polyurethane material to the painted surfaces of the
moldboard and frame is due, at least in part, chemical or molecular
interaction between 100% solids system and the layer of paint.
After the polyurethane protective coating is cured, the snow plow
blade is ready for use. If the moldboard is provided separately
from the frame, the moldboard is installed on the snow plow blade
frame after curing, as is known in the art.
[0019] It will be appreciated that because the 100% solids
polyurethane material is not simply applied over the treated
surfaces of the moldboard and frame, but is instead chemically
bonded thereto, the protective layer formed by the 100% solids
polyurethane material does not easily chip or break away from the
moldboard under the heavy stress and impact conditions frequently
encountered during a snow plowing season. The resulting snow plow
blade is thus provided with a layer of durable protective material
that also improves the plowing efficiency of the snow plow blade by
lowering the coefficient of friction of the plowing surfaces
thereof.
[0020] The coated snow plow blade of the present invention is of a
construction which is both durable and long lasting, and which will
require little or no maintenance to be provided by the user
throughout its operating lifetime. The snow plow blade of the
present invention is also of inexpensive construction to enhance
its market appeal and to thereby afford it the broadest possible
market. Finally, all of the aforesaid advantages and objectives are
achieved without incurring any substantial relative
disadvantage.
DESCRIPTION OF THE DRAWINGS
[0021] These and other advantages of the present invention are best
understood with reference to the drawings, in which:
[0022] FIG. 1 is a front perspective view of a snow plow blade
including a coated moldboard, formed in accordance with the present
invention;
[0023] FIG. 2 is a rear perspective view the snow plow blade
illustrated in FIG. 1;
[0024] FIG. 3 is a perspective view of the coated moldboard
illustrated in FIGS. 1 and 2;
[0025] FIG. 4 is a sectional view the snow plow moldboard shown in
FIGS. 1 through 3, shown with a paint layer and a layer of
protective coating applied thereto;
[0026] FIG. 5 is an articulated snow plow, shown with two coated
snow plow blades, formed in accordance with the teachings of the
present invention; and
[0027] FIG. 6 is flowchart illustrating the process for preparing
the treated snow plow blade of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0028] A coated snow plow blade 32 and method of forming such a
coated snow plow blade 32, in accordance with the teachings of the
present invention, is illustrated in FIGS. 1 through 6. Although
the snow plow blade and methods of the present invention are shown
and described with respect to a straight snow plow 30, it will be
appreciated that the methods of the present invention can be used
to treat and protect any type of snow plow configuration or blade
type, including an articulated snow plow having two distinct snow
plow wings/blades, as illustrated in FIG. 5. Consistent with the
broader aspects of the present invention, the method of the present
invention can be used to coat and protect any surface of the plow
blade, including, but not limited to the moldboard, support frame,
wearstrip, rear scraper and deflector components, in the manner
described herein.
[0029] As illustrated in FIG. 1, the snow plow blade 32 includes a
front, plowing side 34 that will directly impact snow and other
road debris, and a rear side 36 that will be secured to the plow
vehicle (not shown) during operation of the snow plow. Accordingly,
as shown in FIG. 6, in addition to FIGS. 1 and 2, the snow plow
blade 32 is provided in a step 200 and includes, in its simplest
form, a support frame, indicated generally at 40, having a
substantially arcuate overall cross-section and a moldboard 42
secured to the front of the frame 40. Preferably, according to the
teachings of the present invention, the moldboard 42 is welded to
the support frame 40, adding strength, while minimizing the weight
of the finished snow plow blade. In many snow plow designs, the
snow plow blade 32 also includes a cutting edge or wearstrip 43
secured to the front side 34 thereof.
[0030] The frame 40 comprises a top member 44, a bottom member 46
and vertical side members, indicated generally at 48 and 50,
connecting the top and bottom members 44 and 46. The frame 40 can
further include a plurality of support ribs 52, support plates 54
and cross members 56 positioned between the vertical side members
48 and 50 to reinforce the frame 40. Other optional elements such
as brackets for mounting support shoes to the frame 40 and/or
brackets 60 for attaching the snow plow blade 32 to a hitch or
vehicle mounting mechanism (not shown in the Figures) can also be
included on the rear side 36 of the plow blade 32.
[0031] Turning now to FIG. 3, in addition to FIGS. 1 and 2, the
moldboard 42 is typically curved or arcuate in cross section, so
that it can be properly secured to the support frame 40 by one or
more fastening mechanisms 62, such as screws, clips, clamps or
other devices, as are well known to those skilled in the art. The
moldboard 42 has a front face 64 and a rear face 66, opposing side
edges 68 and 70 and top and bottom edges 72 and 74.
[0032] Preferably, the moldboard 42 is constructed of a steel
material. The steel material can include cold rolled steel,
stainless steel, carbon steel or another steel composite or alloy
material, as known to those skilled in the art. Further, other
lightweight metal, alloy or composite materials can be used, such
as those including aluminum or tungsten. It will be appreciated
that the methods of the present invention can be used with
moldboards constructed of thermoplastic material, such as
polycarbonate, if desired.
[0033] As best illustrated in FIG. 4, each of the front face 64,
rear face 66, side edges 68 and 70 and top and bottom edges 72 and
74 of the moldboard 42 is painted in a step 204 with at least one
layer of paint 80. The number of paint layers, color or colors of
the paint layer and the ornamental design of the paint layer is
based on, in part, the material selected for the moldboard, the
type of paint used and the particular end-use application of the
snow plow blade. Where the moldboard 42 is welded into the frame
40, the frame surfaces are also painted with at least one layer of
paint 80.
[0034] In certain preferred embodiments of the present invention,
the paint is a polyurethane based paint, including the desired
pigment color, and additives such as UW or corrosion resistors, if
desired. The polyurethane paint can be one or two-part, and
includes but is not limited to, acrylic-polyurethane,
polyester-polyurethane and other polyurethane blend paints, as are
well known to those skilled in the art. The moldboard 42 can be
brushed, rolled, sprayed or dip coated with the layer of paint 80.
In certain other embodiments of the present invention powdered or
particulated polyurethane paint coating can be applied and cured to
the surfaces of the moldboard 42.
[0035] As will be appreciated, the preferred paint utilized in the
present invention includes a polyurethane resin as at least one of
its binding components. The polyurethane component is formed, as
known in the art, by reaction of an active hydrogen containing
compound, such as a polyol, with a diisocyanate or polymeric
isocyanate component, in the presence of a catalyst, wherein a
sufficient amount of crosslinking occurs between isocyanate groups
(--NCO) and the polyol's hydroxyl end-groups (--OH). In
polyurethane based paint systems, the resulting polyurethane
polymer component is dispersed in an aqueous solution or other
solvent of the paint system. When the paint dries or is otherwise
cured, a thin film or layer of paint, is present on the application
surfaces of the moldboard 42.
[0036] Consistent with the broader aspects of the present
invention, other types of paints, or paints including a
polyurethane component in addition to another binder, can be use to
cover the metal moldboard 42. Such paints can include, but are not
limited to, those containing alkyd, acrylic, epoxy, silicone,
polyester and/or vinyl components.
[0037] Depending on the type of paint selected, each of the front
face 64, rear face 66, side edges 68 and 70, and top and bottom
edges 72 and 74 of the moldboard 42 and frame surfaces can be
cleaned and prepared in a step 202, prior to painting. The
moldboard and frame surfaces are then prepared according to the
paint manufacturer's specifications to ensure proper paint adhesion
thereto. In particular, if a polyurethane based paint is selected,
the moldboard and frame surfaces can be cleaned with alcohol,
solvent or surfactant to remove any oil, grease, dust and/or dirt
present on each of the surfaces.
[0038] In other instances, and depending on the type of paint
selected, the front face 64, rear face 66, side edges 68 and 70,
and top and bottom edges 72 and 74 of the moldboard and frame
surfaces can be grinded or sanded to mechanically dull the surfaces
and remove any rust. Other steps that may be taken to prepare the
moldboard surfaces for painting can include applying a primer, or
chemically treating the surfaces prior to application of the paint
layer 80 to the moldboard 42.
[0039] In a treating or coating step 206, the plowing surfaces,
such as the front face 64 of the moldboard 42, and front surfaces
of the support frame 40 are contacted with a polyurethane coating
material 86, as illustrated in FIG. 4. In addition, the side edges
68 and 70 and top and bottom edges 72 and 74 of the moldboard 42
can be contacted/coated at least partially with the protective
polyurethane coating material 86. The coating step 208 occurs
without mechanical disturbance or chemical treatment of the painted
layer 80.
[0040] According to the teachings of the present invention, the
polyurethane coating material 86 is preferably a substantially 100%
solids elastomeric polyurethane system. Most preferably, the
polyurethane coating material is a 100% solids aromatic
polyurethane system; however, a 100% solids aliphatic polyurethane
system or a combination thereof can also be used. The rigidity of
the layer of polyurethane material 86 depends on the degree of
crosslinking of system, and can be a matter of design choice and
end-use application. The 100% solids polyurethane system utilized
in the present invention is substantially solventless, fast curing,
pigment compatible, abrasion and impact resistant, and corrosion
and UW resistant.
[0041] It will be appreciated that the 100% solids polyurethane
system is also formed, generally, through reaction of an active
hydrogen containing compound, such as a polyol, with a diisocyanate
or polymeric isocyanate component. Preferably, the 100% solids
polyurethane system is a two component system prepared shortly
before application to the moldboard 42.
[0042] During the coating step 208, the polyurethane coating
material 86 is applied directly to the plowing surfaces of the
moldboard and frame, absent/without further treatment or
modification of the desired application surfaces. More
specifically, priming, sanding, UW, plasma and/or chemically
treating or other mechanical or chemical surface preparation of the
moldboard 42 and/or any other snow plow blade component desired, is
not required or advantageous in the methods of the present
invention. The paint layer 80 present on the desired application
surfaces of the moldboard 42 are contacted or treated with the 100%
solids polyurethane system.
[0043] In a curing step 208, the polyurethane coating material 86
is cured on to the front face 64 of the moldboard and desired
surfaces of the support frame 40 to form a substantially smooth
outermost surface thereon. The layer of 100% solids polyurethane
material 86 on the front face 64 of the moldboard and frame
application surfaces has a lower co-efficient of friction than the
painted layer 80 or the bare metal moldboard 42 or frame 40
surfaces. The polyurethane coating layer 86 is preferably sprayed
on to the front face 64, however, the polyurethane coating layer 86
can be brushed, rolled or applied in any manner known to those
skilled in the art.
[0044] Without regard to any particular theory or mode of
operation, substantial preparation of the application surface of
the moldboard 42 and frame 40 is not required because the 100%
solids polyurethane coating chemically interacts, forming at least
one of a covalent, ionic and hydrogen bond, with at least one of
the functional components of the paint layer 80 on the front face
64 of the moldboard 42 and frame 40. The 100% solids polyurethane
coating layer 86 does not merely reside or stick to the outer
surface of the polyurethane-based paint layer 80. Rather, the 100%
solids polyurethane coating material chemically interacts with and
is molecularly bonded to previously applied paint layer 80 at least
at the interface thereof.
[0045] More specifically, and without limitation to any particular
theory, during the curing step 208, the 100% solids polyurethane
system components, including reactive isocyanate groups (--NCO) and
reactive hydroxyl end-groups (--OH), may activate at least a
portion of the functional components of the underlying
polyurethane-based paint layer 80. As such, the activated
functional components provide additional reaction sites for
formation and adhesion of the polyurethane polymer. In addition,
hydrogen bonding can occur between the functional groups of the
paint 80 and the N--H and carbonyl groups of the polyurethane
linkages. As such, the excellent adhesion of the 100% solids
polyurethane material to the painted surfaces of the moldboard and
frame is due, at least in part, to a chemical bond between 100%
solids system and the layer 80 of paint.
[0046] The resulting 100% solids polyurethane coating layer 86 is
not subject to peeling, bubbling, chipping or cracking away from
the painted moldboard surface, as it is chemically bonded to the
layer 80 of paint. The 100% solids polyurethane coating layer 86
therefore provides a durable and impact resistant moldboard, having
a lower coefficient of friction than an uncoated moldboard and
frame, therefore improving not only the strength of the snow plow
blade, but also the snow rolling and plowing efficiency of the snow
plow blade.
[0047] Importantly, and consistent with the broader aspects of the
present invention, the 100% solids polyurethane coating layer 86
can be used to repair a damaged or chipped snow plow blade. In
particular, the method of the invention can be used to fix a
moldboard of a snow plow blade that includes cracks, chips or other
damage to the surface or surfaces thereof. In such a case, the 100%
solids polyurethane coating layer 86 is applied directly over the
cracked or damaged surface without any required surface
preparation, as described above.
[0048] Although the foregoing description of the snow plow blade
and methods of the present invention have been shown and described
with reference to particular embodiments and applications thereof,
it has been presented for purposes of illustration and description
and is not intended to be exhaustive or to limit the invention to
the particular embodiments and applications disclosed. It will be
apparent to those having ordinary skill in the art that a number of
changes, modifications, variations, or alterations to the invention
as described herein may be made, none of which depart from the
spirit or scope of the present invention. The particular
embodiments and applications were chosen and described to provide
the best illustration of the principles of the invention and its
practical application to thereby enable one of ordinary skill in
the art to utilize the invention in various embodiments and with
various modifications as are suited to the particular use
contemplated. All such changes, modifications, variations, and
alterations should therefore be seen as being within the scope of
the present invention as determined by the appended claims when
interpreted in accordance with the breadth to which they are
fairly, legally, and equitably entitled.
* * * * *