Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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FIELD OF THE INVENTION
The present invention relates to devices that are useful for mounting
moldboards onto vehicles and more particularly to devices that are useful for
mounting moldboards used to remove material such as ice and snow from road
surfaces and parking lots where obstructions may likely be encountered and fbr
adjusting the orientation of moldboards with respect to the surface to be
plowed.
This invention also relates to cutting edges for moldboards and to
arrangements for
connecting a cutting edge to a moldboard.
BACKGROUND AND SUMMARY OF THE INVENTION
Moldboards, such as are conventionally used for snow and ice removal, are
well known in the art. Moldboards come in a wide variety of shapes and sizes
depending upon the intended use. Some moldboards are relatively small and
light
and are intended to be mounted on a light domestic truck, i.e., a "pickup
truck".
Other moldboards are of significantly larger size and weight and are intended
for
municipal or commercial use. These larger moldboards are typically mounted on
large trucks which may also be used for spreading sand or salt.
A concern when using a moldboard to remove snow or ice is how to deal
with obstructions occurring on the surface being plowed. Some surfaces are
considerably rougher than others and may have numerous obstructions. Objects
such as orates and manhole covers, rocks, curbs, etc., provide impediments to
the
removal of ice and snow and may damage the lower edge of the moldboard. In
addition. if an obstruction is large enough, the obstruction may cause
significant
damage to the moldboard and may bring the vehicle used in the plowing
operation to
an abrupt halt which may result in injury to the vehicle operator.
Various arrangements have been provided along the bottom edge of a
moldboard to deal with obstructions. These arrangements are commonly called
"trip
mechanisms" and are provided to avoid damage to the moldboard and to the
vehicle
cam~ina the moldboard.
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A representative trip mechanism is described in United States Patent No.
5,079,866, of Gene Farrell, which was issued on January 14, 1992. In the '866
patent, the trip mechanism has a hinged cutting edge along the bottom of the
moldboard with two pivotally mounted linkage members and a trip return spring
provided on each end of the moldboard to resiliently maintain the orientation
of the
cutting edge of the moldboard relative to the surface being plowed. If the
cutting
edge of the moldboard should encounter an obstruction, the pivotally mounted
linkage members act on the plowshoe to cause the moldboard to raise and clear
the
obstruction. After the moldboard has passed beyond the obstruction, the trip
return
springs cause the cutting edge to return to its normal orientation and the
moldboard
returns to its initial position.
A trip mechanism such as is described in the '866 patent or other trip
mechanisms provided along the bottom edge of a moldboard used in snow removal
provide significant protection against damage to the moldboard or to the
surface
being plowed. However, the need exists for different or for additional
protection for
moldboards and for the surfaces being plowed especially in the event that a
moldboard should encounter a substantial obstruction.
Such different or additional protection against obstructions must be
economical in design and construction as well as reliable in operation.
Preferably,
such protection for moldboards against obstructions will have relatively few
moving
parts and will be resistant to damage from rust or from low temperatures
because of
the environment in which such mechanism must function.
In addition to providing protection against obstructions, it is desirable to
adjust the orientation of the snowplow with respect to the surface to be
plowed such
as a street or road depending upon the speed of the vehicle and the conditions
of the
snow or ice or other material to be removed by the plow.
In view of the above background information, it is an object of the present
invention to provide a mounting arrangement for a moldboard which provides
protection against obstructions encountered during plowing.
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A further object of the present invention is to provide a mounting
arrangement for a moldboard providing an improved trip mechanism of high
reliability and low complexity.
It is another object of the present invention to provide a mounting
arrangement for a moldboard having an improved trip mechanism requiring low
maintenance and which is suitable for use in a wet and cold environment.
An additional object of the present invention is to provide a mounting
arrangement for a moldboard having an improved trip mechanism capable of
preventing or significantly reducing damage to the moldboard or to the vehicle
or to
the operator when obstructions are encountered by the moldboard during
plowing.
Yet another object of the present invention is to provide a mounting
arrangement for a moldboard by which the orientation of the moldboard to the
surface to be plowed may be readily varied or adjusted.
Yet still another object of the present invention is to provide a mounting
arrangement for a moldboard by which the orientation of the moldboard to the
surface to be plowed may be subjected to a coarse or gross adjustment as well
as to a
fine adjustment.
Yet another object of the present invention is to provide a plow assembly
having a moldboard and a cutting edge with an arrangement for attaching the
cutting
edge to the moldboard to provide a lower trip for the moldboard.
Still vet another object of the present invention is to provide a plow
assembly
including a moldboard and a cutting edge with an arrangement for attaching the
cutting edge to the moldboard having a resiliency which is compatible with the
resiliency of an upper trip mechanism for the moldboard.
The above objects as well as other objects not specifically mentioned are
accomplished by a mounting arrangement for a moldboard in accordance with the
present invention. The mounting arrangement for a moldboard according to the
present invention comprises truss means for connecting the moldboard to a
vehicle
and arm means for pivotally mounting the moldboard on the truss means. In
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addition, means are provided for resiliently connecting the arm means to the
truss
means. In the preferred embodiment of the present invention, the truss means
includes a mounting member extending longitudinally along the moldboard, with
the
arm means including first and second arm members received at the ends of the
mounting member. In addition, the means for resiliently connecting the arm
means
to the truss means preferably includes a polyurethane member provided at each
of
the first and second arm members between the arm members and the mounting
member. Preferably, the mounting member is square in cross-section and hollow
along the entire length of the mounting member to provide openings at each end
of
the mounting member with the polyurethane members being square in cross-
section
and configured to be snugly received within the openings in the mounting
member.
Preferably, each of the first and second arm members includes a shaft
extending
perpendicularly from said arm member with one of the polyurethane members
being
bound to the shaft of each of the arm members. In the preferred embodiment, a
cam
member is provided on each shaft to limit the extent of angular movement of
the arm
member and the moldboard about the mounting member.
In an alternative embodiment, each of the shafts of the first and second arm
members is square in cross section whereby pivoting of the arm members and the
moldboard about the mounting member causes the polyurethane members to be
compressed inside the mounting member when the moldboard encounters an
obstruction.
The adjustment of the moldboard may be accomplished by a mounting
arrangement for a moldboard in accordance with the present invention
comprising
truss means for connecting the moldboard to a vehicle and arm means for
mounting
the moldboard on the truss means. The arm means includes first and second arm
members with the arm members being connected to the truss means and to the
moldboard at a lower portion of the arm members and with the arm members being
selectively connected to the moldboard at the upper portion of the arm
members. In
the preferred embodiment, the moldboard has a number of spaced apart holes
which
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enables the moldboard to be selectively oriented with respect to the arm
members
and therefore with respect to the surface to be plowed. In addition, in the
preferred
embodiment, the truss means includes adjustment means by which the position of
the arm means with respect to the truss means may be adjusted and thereby
adjust
the position of the moldboard with respect to the surface to be plowed.
In another embodiment of the present invention, the adjustment of the
moldboard may be accomplished by a mounting arrangement for a moldboard
comprising truss means for connecting the moldboard to a vehicle and arm means
for pivotally mounting the moldboard on the truss means. In addition, means
are
provided for resiliently connecting the arm means to the truss means. In the
preferred embodiment of the present invention, the truss means includes a
mounting
member extending longitudinally along the moldboard, with the arm means
including first and second arm members received at the ends of the mounting
member. In addition, the means for resiliently connecting the arm means to the
truss
means preferably includes a polyurethane member provided at each of the first
and
second arm members between the arm members and the mounting member.
Preferably, the mounting member is square in cross-section and hollow along
the
entire length of the mounting member to provide openings at each end of the
mounting member with the polyurethane members being square in cross-section
and
configured to be snugly received within the openings in the mounting member.
The arm means includes first and second arm members with the arm
members being connected to the truss means and to the moldboard at a lower
portion
of the arm members and with the arm members being selectively connected to the
moldboard at the upper portion of the arm members. In the preferred
embodiment,
the moldboard has a number of spaced apart holes which enables the moldboard
to
be selectively oriented with respect to the arm members and therefore with
respect to
the surface to be plowed. In addition, in the preferred embodiment, the truss
means
includes adjustment means by which the position of the arm means with respect
to
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the truss means may be adjusted and thereby adjust the position of the
moldboard
with respect to the surface to be plowed.
Preferably, each of the first and second arm members includes a shaft
extending perpendicularly from said arm member with one of the polyurethane
members being bound to the shaft of each of the arm members. In the preferred
embodiment, a cam member is provided on each shaft to limit the extent of
angular
movement of the arm member and the moldboard about the mounting member.
According to another embodiment according to the present invention, a
cutting edge is provided along the lower edge of the moldboard with a
polyurethane
strip provided as a hinge for mounting the cutting edge to the moldboard. In a
more
preferred embodiment of the present invention, the polyurethane strip is
formed with
a polyester backbone and is cured using an MBCA agent. Preferably the
polyurethane and curing agent are mixed at 101 % of theory to achieve a
desired
resiliency or stiffness. In addition, the thickness of the polyurethane strip
is
preferably 1.375 inches to 1.75 inches and the width of the polyurethane strip
is
preferably 5.5 inches.
BRIEF DESCRIPTION OF THE DRAWINGS
The preferred embodiments of the present invention will be described in
greater detail with reference to the accompanying drawings, wherein like
members
bear like reference numerals and wherein:
Fig. 1 is a pictorial view of a moldboard according to the present invention;
Fig. 2 is a side view of a mounting arrangement for a moldboard according to
the present invention;
Fig. 3 is a view through the line 3-3 of Fig. 2;
Fig. :~ is a view through the line 4-4 of Fig. 2;
Fig. 5 is a view through the line 5-5 of Fig. 2;
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Fig. 6 is a cross sectional view of an arm member and resilient member
according to the present invention;
Fig. 7 is a cross sectional view of another embodiment according to the
present invention;
Fig. 8 is a side view in partial cross-section of the mounting arrangement for
adjusting the orientation of a moldboard relative to the surface to be plowed
according to the present invention in the normal position;
Fig. 9 is a side view in partial cross-section of the mounting arrangement for
adjusting the orientation of a moldboard relative to the surface to be plowed
with the
moldboard in a more vertical orientation;
Fig. 10 is a side view in partial cross-section of the mounting arrangement
for adjusting the orientation of a moldboard relative to the surface to be
plowed with
the moldboard in an intermediate position;
Fig. 11 is a side view in partial cross-section of the mounting arrangement
for adjusting the orientation of a moldboard relative to the surface to be
plowed with
a relatively fine adjustment of the orientation of the moldboard; and,
Fig. 12 is a front view of a moldboard having a cutting edge mounted on the
moldboard with a polyurethane strip.
DETAILED DESCRIPTION
A preferred embodiment of a mounting arrangement according to the present
invention is shown the accompanying drawings. With reference to Fig. 1, a
moldboard 100 of conventional design is carried by a truss 102. The truss 102
is
arranged to be removably mounted on the front of a truck or other suitable
vehicle
(not shown) through a bracket 104 in a suitable and conventional manner well
known in the art. The truss 102 has a mounting member 106 which is formed from
steel square tubing and which comprises a box beam, i.e., a member having a
square
cross-section, which is hollow along the length of the box beam.
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The mounting member 106 is carried on the truss 102 by an A-frame
member 108. The mounting member 106 is pivotally attached to the A-frame
member 108 at a mid-point of the mounting member 106 with a pair of hydraulic
cylinders 110 provided on either side of the A-frame member 108. The hydraulic
cylinders 110 are provided to selectively orient the mounting member 106, and
therefore to selectively orient the moldboard 100, with respect to the truss
102: In
this way, the angle that the moldboard makes with respect to the vehicle may
be
varied as desired.
In addition, the truss 102 includes an arrangement 112 to lift the moldboard
~ 100 when desired. The arrangement 112 includes a support arm 114 which is
piv otally attached to the truss 102. The A-frame member 108 may be attached
to the
end of the support arm 114 by a chain 116. In addition, the support arm 114
may be
raised or lowered by a hydraulic cylinder 118 to raise or lower the A-frame
member
108, and thereby raise or lower the moldboard 100'.
If desired, the truss 102 may also include headlights 120 to illuminate the
roadway in front of the moldboard 100.
If desired, the cutting edge 124 of the moldboard may be made of a flexible
or resilient material in order to minimize damage to the moldboard in the
event that
the cutting edge 124 should strike an obstruction during plowing. The cutting
edge
124 may also be provided with a trip mechanism such as is described in United
States Patent No. 5,079,866.
The moldboard 100 includes a frame 126 which includes a series of curved
support members 128. The support members 128 are connected at their uppermost
and lowermost portions to an upper cross member 130 and to a lower cross
member
132. Two additional support members 132 are provided adjacent the left and
right
sides of the moldboard 100 and are provided to connect the moldboard 100 to
the
truss 102.
The additional support members 132 include a hole 134 which receives a
bolt 136 positioned centrally within an end of the mounting member 106. The
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additional support members 132 also include a series of holes 138 provided at
about
a midpoint of the frame 126. A pair of arm members 140 formed of steel are
carried
by the mounting member 106 and the arm members in turn carry the moldboard
100.
The series of holes 138 permit the orientation of the moldboard with respect
to the
arm members 140 to be selectively adjusted.
With reference now to Fig. 2, the mounting member 106 includes a pair of
A-frame pivot bearings 142 at a mid-point of the mounting member 106. The
mounting member is free to pivot about the pivot bearings 142 with respect to
the A-
frame member 108 (see Fig. 1). The mounting member 106 also includes a number
of power angling bushings 144. The hydraulic cylinders 110 are connected to
the
mounting member 106 through selected power angling bushings 144.
The mounting member 106 is square in cross section with an opening 146
provided in a side wall of the mounting member 106 adjacent the vehicle to
enable
the hydraulic cylinders 110 to be connected to the power angling bushings 144.
In a moldboard mounting arrangement according to the prior art (not shown),
the arm members 140 have a projection made from steel square tubing which
extends at a right angle with respect to the arm member 140. The projection is
formed from a rigid box beam having a square configuration in cross-section
with
the projection sized so as to be snugly received within the ends of the
mounting
member 106. In the prior art arrangement, the arm members 140 are slidingly
received within the mounting member and cannot pivot or rotate with respect to
the
mounting member 106.
According to the present invention, the arm members 140 are each provided
with a resilient member 148 (see Fig. 6). The resilient member 148 has a
square
cross section and is sized so as to be snugly received within the opening
provided at
either end of the mounting member 106.
The resilient member 148 enables the arm member 140 to pivot with respect
to the mounting member 106. The resilient member 148 preferably has sufficient
rigidity to prevent the arm member (and therefore the moldboard) from pivoting
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about the mounting member 106 during normal operation of the plow in the
absence
of an obstruction. The flexibility of the resilient member 148 is measured in
durometers and a suitable value depends upon the size and weight of the
moldboard
as well as the flexibility or resiliency desired for the resilient members
148. For a
typical moldboard of a light weight to medium weight construction, a durometer
of
about 330 pounds per linear inch is likely to be suitable.
In the preferred embodiment, the resilient member is connected to the arm
member 140 through a shaft 150. The shaft 150 is either integral with the arm
member 140 or is welded to the arm member at one end of the shaft 150. The
shaft
150 has a sufficient diameter to enable the shaft to be provided with a
threaded
opening 152 extending through the arm member 140 to receive the bolt 136 (not
shown in Fig. 6, but see Fig. 1). The bolt 136 passes through the lower hole
provided in the additional support members 138 of the moldboard frame to
connect
the moldboard to the arm members. The shaft 150 is preferably centrally
located in
the resilient member 148 so that the shaft 150 is likewise centrally located
in the end
of the mounting member 106. In this way, the arm member 140 and the moldboard
100 are arranged to pivot about the shaft 150.
With reference now to Fig. 3, the arm member 140 has the first hole 152
provided in a lower portion of the arm member having a generally square
configuration. The arm member 140 includes an upwardly extending portion
provided with a second opening 154 which receives a second bolt (see also,
Fig. 1 )
to connect the additional support member 132 to the arm member 140 through one
of the series of holes provided in the additional support member at a mid-
point of
the moldboard 100.
With reference to Fig. 4, the resilient member 148 is snugly received within
the square opening provided in the end of the mounting member 106. Because the
resilient member 148 is securely bound to the surface of the shaft 156,
rotation of
the shaft causes a deformation of the resilient member 148 inside the mounting
member 106. The extent to which the resilient member resists deformation
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determines the amount of force needed to rotate the arm member 140 about the
shaft
156.
With reference now to Fig. 5, to limit the angular range of motion of the arm
member 140 about the shaft 156, the shaft may be provided with a cam member
160.
The cam member 160 is fixed with respect to the shaft 150 and with respect to
the
arm member 140 such as by welding. The cam member 160 has four relatively flat
surfaces 162 which contact the inside surface of the mounting member when the
arm
member 140 is in the rearwardmost position relative to the vehicle. The cam
member 160 likewise has four additional relative flat surfaces 164 which abut
the
inside surface of the mounting member when the arm member 140 has moved
sufficiently forward. In this way, the cam member 160 serves to limit the
angular
extent of movement of the arm member 140 and in turn limit the angular extent
of
movement of the moldboard 100 about the shaft 156.
The cam member 160 may be welded in the valleys between the flat portions
about the perimeter surface of the cam member in order to increase the
strength of
the cam member.
Preferably, the cam member prevents rotation of the moldboard about the
shaft 1 SO to about 22.5 degrees and usually less than about 35 degrees of
rotation in
the event that the moldboard encounters an obstruction.
To adjust the ability of the resilient member to oppose a rotation of the
moldboard about the shaft 150, the length of the resilient member may be
varied as
well as the composition of the resilient member. For example, longer and
therefore
heavier moldboards likely require either longer resilient members 148 or
resilient
members of a material having a relatively higher durometer.
The mounting arrangement for a moldboard according to the present
invention provides significant protection against damage to the moldboard or
to the
vehicle used for plowing and the vehicle operator (as well as to preventing
damage
to obstructions) in the event that the moldboard should encounter an
obstruction
during plowing. However, additional protection is provided when the mounting
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arrangement according to the present invention is used in conjunction with a
conventional trip mechanism for a moldboard. Preferably, the mounting
arrangement according to the present invention is used in conjunction with a
lower
trip mechanism for a moldboard in which a polyurethane strip according to the
S present invention connects the cutting edge to the moldboard.
With reference now to Fig. 7, an alternative embodiment is disclosed in
which the arm member 140 is pro~zded with a square shaft 150'. The square
shaft
150' is welded to the arm member 140 and is oriented so that the corners of
the
square shaft are adjacent the flat interior surfaces of the mounting member
106 when
the arm member 140 is in the rear<vardmost position. When the arm member 140
rotates fonvardly (such as when the moldboard 100 encounters an obstruction),
the
flat exterior surfaces of the square shaft 150' compress the resilient member
148'
against the inside surfaces of the mounting member 106. In this way, the
resistance
of the resilient member to being compressed prevents the moldboard 100 from
rotating forward about the central axis of the square shaft 150'. As in the
embodiment of Fig. 3, the moldboard is connected to the arm member 140 through
a
bolt 136 which is threadably received by the arm member 140 and by the square
shaft 150'.
The square shaft 150' may be solid, if desired, or may be hollow depending
upon the weight of the moldboard and the thickness of the walls of the square
shaft
150'
The resilient member 148 may be formed of any number of materials readily
apparent to one skilled in the art with a suitable material being Adiprene LF
1860A
(Adiprene is a trademark of Uniroval Chemical Company, Inc. of Middlebury,
Connecticut). :mother suitable material is Adiprene LF 1800A. Both Adiprene LF
1800A and Adiprene LF 1860A may be cured with MBCA (4,4'-methylene-bis-(o-
chloroaniline)) (MBCA Activator VI is available from Miki Sangyo USA, Inc. and
viBCA Bis Amine A is available from Omni Spec. Corporation-formerly Palmer
Davis Sieka). In addition, when the Adiprene is being cured in a mold, it is
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preferable (or necessary) to use a mold release such as Mold Release S236TM
available
from Stoner. If the shaft 150 (or the square shaft 150 is to properly bind to
the
polyurethane, the surface of the shaft must be prepared. Suitable preparation
involves a grit blasting of the shaft using G40 or G50 steel or aluminum oxide
60
mesh at.80-100,p.s.i. In addition, Adiprene Primer Chemlock AP213 or AP218
available from Hughson Chemicals, Division of Lord Corporation, Erie
Pennsylvania maybe used to facilitate the attachment of the polyurethane to
the
shaft.
A suitable process for bonding liquid cast Adiprene to metal surfaces
includes the following steps:
1. Degrease metal surfaces with suitable solvent to reduce
contamination of grit.
2. Grit blast metal surfaces to be bonded with G40 or G60 steel grit or
aluminum oxide-60 mesh at 80-100 p.s.i. air pressure.
3. Degrease metal with solvents; toluene, methyl ethyl ketone,
trichloroethylene or perchloroethylene. (Avoid using fast evaporating solvents
which
may cause moisture condensation on the metal surfaces and result in poor
adhesion.)
Prepare surfaces just before application of the primer to prevent rusting and
contamination. Care should be taken in the selection and application of mold
releases to avoid contamination from mold releases on the surfaces intended to
be
bound to the Adiprene.
4. Apply one or more primer coats and allow to dry.
5. Preheat metal part and mold to about 212 degrees Fahrenheit before
casting.
6. Cast mixture of Adiprene prepolymer and crosslinking agent and cure
according to manufacturer's instructions.
In operation, a moldboard mounted on a vehicle using the mounting
arrangement according to the present invention may be used for plowing
material
such as ice and snow from a road or other surface. In the event that the
moldboard
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should encounter an obstruction, the resilient material provided about the
shaft of the
arm members permits the moldboard to pivot forward about 22.5 degrees and
preferably less than about 35 degrees to permit the moldboard to pass over the
obstruction. In this way, the damage to the moldboard, to the vehicle carrying
and
S moldboard and, most importantly to the operator of the vehicle, from
encountering
the obstruction is either prevented or significantly reduced.
A preferred embodiment of a mounting arrangement for adjusting the
orientation of the moldboard with respect to the surface to be plowed
according to
the present invention is shown especially in connection with Figs. 8-11 of the
accompanying drawings. With reference to Fig. 8 (and with continued reference
to
Fig. 1), the moldboard 100 is carried by the truss 102 with the truss 102
arranged to
be removably mounted on the front of a truck or other suitable vehicle (not
shown)
through the bracket 104 (not shown in Fig. 8). As shown in Fig. l, the truss
102
includes the mounting member 106 which is formed from steel square tubing and
which comprises a box beam, i.e., a member having a square cross-section,
which is
hollow along the length of the box beam.
The mounting member 106 is carried on the truss 102 by the A-frame
member 108. The mounting member 106 is pivotally attached to the A-frame
member 108 at a mid-point of the mounting member 106 with the pair of
hydraulic
cylinders 110 (not shown in Fig. 8) provided on either side of the A-frame
member
108.
In addition, the truss 102 includes the arrangement 112 to lift the moldboard
100 when desired. The arrangement 112 includes the support arm 114 which is
pivotally attached to the truss 102. The A-frame member 108 may be attached to
the
end of the support arm 114 by the chain 116. In addition, the support arm 114
may
be raised or lowered by the hydraulic cylinder 118 to raise or lower the A-
frame
member 108, and thereby raise or lower the moldboard 100.
If desired, the truss 102 may also include headlights 120 to illuminate the
roadway in front of the moldboard 100.
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As described above, the cutting edge 124 of the moldboard may be made of a
flexible or resilient material in order to minimize damage to the moldboard in
the
event that the cutting edge 124 should strike an obstruction during plowing.
Especially if the cutting edge 124 is of steel or some other rigid material,
the cutting
edge may be connected to the moldboard by a polyurethane hinge 125 which
extends substantially along the length of the moldboard 100 and the cutting
edge
124. The polyurethane hinge 125 is bolted to the lower edge of the moldboard
100
by a series of bolts 127 which extend through holes in the moldboard 100 and
through holes in the polyurethane hinge 125. Similarly, the cutting edge 124
is
connected to the polyurethane hinge 125 by a series of bolts 129 which extend
through holes in the cutting edge 124 and through holes in the polyurethane
hinge
125. When the cutting edge encounters an obstruction, the polyurethane hinge
125
may bend in order to allow the cutting edge to pivot with respect to the
lowermost
edge of the moldboard and thereby pass over the obstruction. The resiliency of
the
polyurethane hinge 125 may be varied as desired in order to adjust the ability
of the
cutting edge 124 to pivot with respect to the lowermost edge of the moldboard.
In the preferred embodiment of the present invention, the polyurethane hinge
has a polyester backbone with the polyurethane hinge 125 being made of
Adiprene
LF 1860A (Adiprene is a trademark of Uniroyal Chemical Company, Inc. of
Middlebury, Connecticut). Another suitable material is Adiprene LF 1800A. Also
in the preferred embodiment, the polyurethane hinge has been cured with MBCA
(4,4'-methylene-bis-(o-chloroaniline)) (MBCA Activator MTM is available from
Miki
Sangyo USA, Inc. and MBCA Bis Amine A is available from Omni Spec.
Corporation-formerly Palmer Davis Sieka).
As described above in connection with the upper trip mechanism, when the
Adiprene is being cured in a mold, it is preferable (or necessary) to use a
mold
release such as Mold Release S236TM available from Stoner.
When.preparing the mixture of Adiprene prepolymer and crosslinking agent
to form the polyurethane hinge 125, it is preferable to calculate the mixture
at 101%
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of the theoretical mixture and then cure the mixture according to the
manufacturer's
instructions. In other words, to obtain a predetermined (or desired) durometer
for
the polyurethane hinge, a particular mixture of Adiprene and MBCATM can be
calculated theoretically. In practice, that mixture should be prepared at 101%
of the
theoretical mixture in order to achieve the predetermined (or desired)
durometer for
the polyurethane hinge.
For a moldboard having a length of 8 feet, it is preferable for the
polywethane hinge to have a width of 5.5 inches so as not to extend too low on
the
cutting edge or too high on the moldboard. If the polyurethane hinge extends
too
low, usually more than 30 % of the cutting edge height; then the useful life
of the
cutting edge will be diminished because the cutting edge is subject to wear
during
use. If the polyurethane hinge 125 extends too high on the moldboard, the
hinge
will interfere with the structure of the moldboard and with the adjustment and
positioning of the moldboard.
For a moldboard having a length of 8 feet, it is preferable that the
polyurethane hinge extends substantially along the entire length of the
moldboard
and that the polyurethane hinge has a thickness of at least 1.375 inches. If
the length
of the moldboard is 10 feet, it is preferable for the thickness of the
polyurethane
hinge to be 1.750 inches.
20. With reference now to Fig. 12, in the preferred embodiment of the lower
trip
mechanism, the bolts 129 which connect the cutting edge 124 to the lower
portion of
the polyurethane hinge 125 are preferably spaced 12 inches apart with the
bolts at
either end of the cutting edge being at least 6 inches and no more than 12
inches
from the sides of the cutting edge 124. The bolts 127 which connect the lower
edge
of the moldboard to the upper edge of the polyurethane hinge 125 may be spaced
apart 8 or 9 inches with the bolts at either end of the moldboard being at
least 6
inches and no more than 12 inches from the sides of the moldboard.
The arrangement for mounting a cutting edge on the lowermost edge of a
moldboard using a polyurethane hinge according to the present invention may be
CA 02510727 1999-06-07
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used n~ith or without the upper trip mechanism and with or without the
arrangement
for adjusting the orientation of the moldboard. If the polyurethane hinge is
used in
conjunction with an upper trip mechanism according to the present invention,
the
durometer of the polyurethane strip and the durometer of the polyurethane
members
in the upper trip mechanism should be configured so as to provide the desired
relative resiliency for the upper and lower trip mechanisms.
As described in connection with Fig. 1, the moldboard 100 includes the
frame 126 which includes the series of cowed support members 128 (not shown in
Fig. 8). The t<vo additional support members 132 are provided adjacent the
left and
right sides of the moldboard 100 and are provided to connect the moldboard 100
to
the truss 102.
The additional support members 132 each include the hole 134 which
receives the bolt 136 positioned centrally within the end of the mounting
member
106. The additional support members 132 also include the series of holes 138
1 S provided at about a midpoint of the frame 126. The holes 138 are
preferably set
apart ~ degrees to 7 degrees depending upon the size of the moldboard and the
range
of adjustability desired.
A pair of arm members 140' formed of steel are carried by the mounting
member 106 and the arm members in turn carry the moldboard 100. The arm
members 140' according to the embodiment of Fig. 8 are curved forwardly (in
the
same direction as the curvature of the moldboard) in order to more easily
avoid
obstruction with the configuration of the moldboard and mounting arrangement.
The degree of curvature of the arm members 140' is a matter of design choice
as will
be readily apparent to one skilled in the art.
The series of holes 138 permits the orientation of the moldboard with respect
to the arm members 140 to be selectively adjusted, as will be more fully
described
below.
The arm member 140' has the first hole 152' provided in a lower portion of
the arm member having a Qenerally square configuration. The arm member 140'
CA 02510727 1999-06-07
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includes an upwardly extending portion provided with a second opening 154'
which
receives a second bolt (see also, Fig. 1) to connect the additional support
member
132 to the arm member 140' through one of the series of holes provided in the
additional support member at a mid-point of the moldboard 100.
In the normal position, the arm members 140' are connected to the
moldboard through the middlehole 138 in each of the support members 132.
However, other orientations of the moldboard (and hence the cutting edge) to
the
surface to be plowed may be desirable depending upon the conditions of the
surface
to be plowed. For example, if the cutting edge is oriented in a more vertical
angle,
the cutting edge will more easily hop or skip over an obstruction. If the
cutting edge
is oriented at a flatter or more horizontal angle to the surface to be plowed,
the
cutting edge will glide over the surface to be plowed more easily but the
cutting
edge will also tend to trip only after the forward edge of the cutting edge
has
jammed into an obstruction.
With reference now to Fig. 9, the moldboard has been moved relative to the
arm members 140' so that the hole 154' aligns with the rearwardmost hole 138
in the
support members 132. This may be accomplished by first removing the bolt from
the holes 154' and 138, repositioning the moldboard (i.e., by extending the
hydraulic
piston 118 to lift the member 108) and then reinserting the bolts when the
holes 154'
are aligned with the rearwardmost holes 138 in the support arm.
Having the moldboard in the orientation of Fig. 9 positions the cutting edge
at a relatively vertical orientation to the surface to be plowed. This
orientation is
most useful in the case of heavily packed snow and ice. However, this angle of
orientation is preferably only used when the snowplow is moving at about 5
miles
per hour or less in order to avoid damage to the moldboard or to the surface
being
plowed.
For high speed plowing operations, the moldboard is mounted to the arm
members 140' using the more forward holes 138 (configuration not shown).
CA 02510727 1999-06-07
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In addition, with reference to Fig. 10, an intermediate position may be
selected as desired depending upon the conditions of the surface to be plowed.
In the event that a more precise adjustment of the orientation of the cutting
edge to the surface to be plowed is desired, the mounting position of the A-
frame
member 108 to the truss 102 may be changed. With reference to Fig. 8, the
truss
102 is provided with a mounting bracket 170 which has a pair of upper holes
172
and a pair of lower holes 174. Similarly, the A-frame member 108 has a
mounting
bracket 176 which has a number of holes 178 arranged vertically. With
reference to
Fig. 11, the A-frame member 108 may be raised or lowered with respect to the
truss
102 in order to align different holes in the mounting brackets 170, 176. In
this way,
the orientation of the A-frame member 108 with respect to the surface to be
plowed
is slightly varied and thereby the orientation of the moldboard 100 and the
cutting
edge 124 with respect to the surface to be plowed is similarly varied.
The mounting arrangement having the capability to adjust the orientation of
the moldboard with respect to the surface to be plowed may be used with or
without
the resilient mounting members and with or without the polyurethane hinge for
the
cutting edge.
The principles, preferred embodiments and mode of operation of the present
invention have been described in the foregoing specification. However, the
invention which is intended to be protected is not to be construed as limited
to the
particular embodiments disclosed. The embodiments are therefore to be regarded
as
illustrative rather than as restrictive. Variations and changes may be made
without
departing from the spirit of the present invention. Accordingly, it is
expressly
intended that all such equivalents, variations and changes which fall within
the spirit
and scope of the present invention as defined in the claims be embraced
thereby.
