Note: Descriptions are shown in the official language in which they were submitted.
Title: BLADE WITH WEAR RESISTANT EDGES
21~09~9
- FIELD OF THE INVENTION
The present invention relates to scraping blades for road
working and earth moving equipment. More specifically, the present
invention relates to blades of the type having a wear resistant edge
which are adapted for use in earth and road working machines such as
graders, snowplows and the like.
8ACKGROUND OF l H ~ TION
Many di~rerent types of vehicles are used to work a surface.
Such vehicles include bulldozers and graders which may be used to
flatten or smooth dirt surfaces for the purpose of construction, and
15 snowplows, which are prim~rily used on asphalt or hard top roads for
the purpose of yLIshillg snow off the c~ eway. In most of these types
of vehicles, and in particular in snow removal vehicles, the vehicle is
provided with a moldboard to which snowplow blades or other blades
may be ~tt~rh~-l. The moldboard is a permanent fixture of the vehicle;
2 0 the blades can be removed and replaced as they become worn, broken or
the like.
Developments in tungsten carbide inserts have led to a
wear resisL~It edge being formed in the lower edge of the replaceable
2 5 blades. The wear resislanl edge is typically colll~llccd of a plurality of
short pieces of tungsten carbide which are welded or otherwise attached
to the body of the blade. While ~;leatly i~ rovillg the wear life of the
blade and illlyroving efficiency by reducing the number of stoppages
d to remove and replace the worn blades, this blade is not totally
3 0 s~ tory. In particular, once the WOl~illg edge of the blade is worn it
is still n~cs~. y to di~i~ose of the remainder of the body of the blade as
scrap. The blades are typically formed from three quarters of an inch to
one inch thick steel plate which may be 6 to 10 inches high, and the
disposal of such blades is a cor~ le waste.
U.S. Patent 3,934,654 to Stephenson et. al. teaches that
- 2 ~ 2 1 1 09 49
efficiency can be increased by using a two part grader blade. The first part
bolts onto the moldboard, and the second part bolts onto the rear of the
first part. The second part carries wear resistant inserts along a lower
edge. The second part is made smAll~r and thinner than a conventional
5 blade, so that there is less scrap when the wear resistant inserts are worn
out. However, because this is a two part blade, it is more cumbersome
and .liffi~llt to install. Further, because the second part is smAll~r and
thinner it is more prone to being ~AmA~e-l during use.
U.S. Patent 5,224,555 teaches a blade with i~ n~ed wear
resistance, by means of a more substantial (i.e. thicker) wear resistant
insert. However, this design is not that pr~ctir~l, because it ~resellls the
insert on the leA~ing edge of the blade, in a manner that is likely to
promote fracturing and disinle~lalion of the inserts. In general, the
15 inserts, while being r~si_lallt to wear, are quite brittle, and will fracture under sharp impacts. Also this inært is formed with a slot, into which
a tongue of metal from the blade is inserted. The co~ iPntc of thermal
e~ ion for the blade body metal and the tungsten carbide inserts are
dirfer~nt, leading to dirrerenlial heating and cooling stresses and
20 frActllring problems during welding. Thus, a thicker insert is not that
practical. Therefore, to simply increaæ the size of the insert, to try to
illl~iOVe wear life, while at the same time exposing the inset to more
fracturing does not lead to any real illl~rov~lllent. The difficulty
therefore is how to provide more wear resislcu.ce, and thus a longer
2 5 l~ctin~ blade, which reduces waste, and which o~er~cjllles the problems
~cso. ;~(e~ with such prior art sollltiQns.
SUI~fMARY OF I-~F ~NV~TION
What is desired therefore is a way of increasing the
3 0 efficiency of the uæ of blades having a wear resisl~ll edge, and reducing
the waste associated with disposal of such blades. rrerelably such
- 3 2110949
increase in efficiency should be accomplished without sacrificing any
utility of the blade nor decreasing the efficiency of the workers by
requiring frequent blade replAcemPrlts. The blade should be durable, and
the inserts not easily damaged by being overly exposed. It would also be
preferable if the blades were easily adaptable to different working
conditions.
Thefefore, according to the present invention there is
provided:
a wear resistant blade for working a surface by being
mounted on a mol-lhoard of a vehicle, the blade CO~ l~illg:
a ~nPr~lly rectangular body having a length, a height, and
a thil~ness, and having generally parallel top and bottom edges and
having side edges;
at least one mounting means formed along each of said top
and bottom edges;
a plurality of wear resistant PlPmPrlt~ mounted in said
mounting means along both said top and bollolll edges to form a wear
nt edge along both the top and bollo,l, edges; and
a plurality of mounting apell~lres formed in said body for
mounting said blade onto said moldboard of said vehicle;
eleul said moldboard irlcltl~lp~ a plurality of attA~hmPrlt
points and said mounting apellulcs formed in said body of said blade
collc~ond to and register with said attachment points wherein said
25 blade body can be ælte-nAtely moullLed to said moldboard in a first
position in which said top edge having said wear resistant edge is in
l UU;UIg contact with said surface to be worked and becomes a working
edge and a secor ~1 position in which said bollolll edge having said wear
le~isl~lt edge is in lUlUUllg contA~t with said sllrfA~e to be worked and
3 0 becom~ a working edge.
4 2110g~9
-
LIST OF FIGURES
Reference will now be made, by way of example only, to
~re~lred embodiments of the illv~lion as illustrated in the following
figures in which:
Figure 1 is a perspective view of a blade with wear resistant
edges according to the present illv~llion;
Figure 2 is a perspective view of a æcond embodiment of a
blade having wear resistant edges;
Figure 3 is a plan view showing a universal bolt hole
1 0 pattern;
Figure 4 is a side view in part section along lines A-A
showing one type of wear rPsicl~t PlPm~nt;
Figure 5 is the same view as Figure 4 showing a second type
of wear lesislal.l elPmPnt;
Figure 6 is the same view as Figure 4 showing a third type
of wear lesi~ ll element;
Figure 7 is the sarne view as Figure 4 showing a fourth type
of wear lesisl~lt element;
Figure 8 is a side view along line 8-8 in Figure 2;
2 0 Figure 9 is a full side view along lines 9-9 in Figure 1;
Figure 10 is a side view of a third embodiment of the
~resellt invention; and
Figure 11 is a side view through a fourth embodiment of
the present i~lvt:nlion.
DFTAn.F.n nF.~c~ oN OF ~ l;KRFn Fl~RoDrl~IFNTs
A wear r~;cl~t blade accordil~g to the t,resent i,l~enlion is
shown as 10 in Figure 1. The wear resislO~-l blade includes a body 12
3 0 which has a length 14, a height 16 and a thickness 18. As can be seen
from Figure 1, the length 14 is generally glealel than the height 16 and
211094~
the height 16 is generally much greater than the thickness 18. Also
shown are top and bottom edges 20 and 22 and shorter side edges 24 and
26. The top and bottom edges are generally parallel for reasons that will
become apparent below. In the embodiment of Figure 1 the blade body
5 12 is a solid rectangular blade. In the embodiment of Figure 2, the blade
body 12 is formed with a plurality of teeth 21, 23 at the working edges, as
may be specially suited for gravel roads or the like.
Each of the top and bottom edges 20 and 22 include a
mounting means formed therealong. In this sense a mounting means
1 0 refers to a structure for allowing attachment of a plurality of wear
resistant ele~n~nts 30, along the edges 20, 22. In the preferred
embodiment, the mounting means coll,ylises a slot which may be
milled into the body 12 as ~lPccrihed hereafter. Turning to Figure 4 for
example, it can be seen that there is a generally rectangular (in side view)
1 5 slot 32 which has been milled into the body 12. The slot ~re~lably runs
the full length of the edges 20, 22. Wear resistant elements are then
mounted in the mounting means or slot 32 as shown. Turning to
Figure 8, it can be seen that for the embodiment of the invention as
rli~close~ in Figure 2, the slot may also be in the form of a rectangular
2 0 cutaway from the front of the blade body 12 as shown at 33.
Figures 4 through 8 illustrate differellt types of wear
resistant elements 30. Each of these wear resistant elements 30 is
preferably formed from a highly wear resistant material, such as
tungsten carbide. A plurality of these elements 30 would be inserted side
2 5 by side into each mo.~ means or slot 32. In this side by side position
the wear Ic:jiskult elements form a generally cc,lllilluous wear resistant
edge. In some ~ gl ~cP~, such as for snowplow blades, it is ~re~lled
if the individual elen~pnts are in abutting contact. In other
circumstances the wear resistant elements may be mounted into
3 0 individual teeth which may be formed on a blade having a toothed edge,
each tooth se~alaled by a gap, such as may be used for gravel or the like
- 6 ~ 21109 ~9
(for example, see Figure 2). In both cases however, the lower edges of
the elements 30 form a wear resistant edge for bearing against the surface
to be worked. Por the purposes of this invention, each blade will be
considered to have a wear resistant edge by means of the side by side
5 mounting of the wear elements.
The ~iefelled method of mounting the wear resistant
elements or inserts is to use induction brazing which essentially welds
the tungsten carbide inserts on both sides 34 and around the back 36 into
the slot 32, or at the back and the top of rectangular slot 33.
The tungsten carbide inserts are ~ref~lably about 1 inch
long, and may be any one of various physical styles or shapes as shown
in Figures 4 through 7. Pigure 4 shows a bull nose wear element, Figure
5 shows a roof top wear PlPmPnt, Figure 6 shows a 250 trapezoid
PlPmPnt, and Figure 7 shows an M.T.C. a~loved trapezoid element, and
15 Figure 8 shows a front mounted square edged wear element. Ple~erdbly
the wear rP~ict~nt elements or inserts 30 will be made from high wear,
mining grade tungsten carbide, which gives good results. As will be
a~re~ te-l by those skilled in the art, even harder grades of tungsten
carbide can be used, but the harder the insert 30, generally the more
2 0 brittle the matPri~l tends to be. Material that is too brittle will break and
fracture before v~e~llg thus reducing the wear life of the blade. High
wear mining grade provides a reasonable colllproll-ise between wear
esislal~ce and brittleness and thus is ~l~f~,led.
Turning now to the blade body 12, the ple~lled thickness
2 5 18 of the blade body 12 can range between one half inch to one and a half
inches depending on the application. The most ~lefeir.2d thicknesses
are ~h~e~ three ~ ~t~.~ of an inch and one inch. The length 14 of the
blade can vary from 4 inches to 160 inches although the most ~refe,led
lengths are 44 inches and 48 inches. The height 16 can very between 4
3 0 inches and 10 inches although the most ~le~l.~d height is 5 to 6 inches.
The ~le~.led m~tPli~l for the blade body 12 is carbon steel,
7 2110g49
such as AISI C 1020, although up to C 1045 may be used. As will be
ayyrc~:iated by those skilled in the art, the higher the C number generally
the grcalel the hardness, and a constraint on the hardness is the ease of
milling the slot 32 into the edges of the blade body. Thus, satisfactory
5 results have been achieved with the afore-mentioned steel, but other
types of hardened steel may also be used.
Shown in Figure 3 is a universal attachment hole pattern
for a plurality of mounting apcll.lles 50. The universal pattern shown
is yre~clably used on a blade se~n~nt of 44 inches length and six inches
10 in height. The pattern consists of two parallel rows of bolt holes 51, 53,
which begin and end two inches in from each side edg. The rows 51, 53
thernselves are formed from ~ chment or bolt holes 50 on four inch
ccllhes. Plc~ld~ly, the parallel sets or rows are spaced two inches apart
from each other. In this manner, each row or set of bolt holes 51, 53 is
15 four inches away from a collc~yonding wear or working edge. The
attachment holes 50 are used to presellt altemate wear edges to the
surface to be worked. In particular, set or row 51 is associated with and
compl~ ry to the top edge 20 and set or row 53 is associated with
and comp4m~nt~ry to the bottom edge 23.
The pre~erled means of attachment of the blade body to a
mold- board of the vehicle is to use carriage bolts or domed head plow
bolts. The bolts are placed into the countersunk apertures 50, slid
through the blade body and a co~ ",ding aye~lure on the moldboard
of the vehicle, and a nut is then placed on the remainder of the bolt
2 5 which extends from the rear of the moldboard. In this manner the blade
body 12 can be se~:ulcd to the mol~hoard. It will be aypre~:iated that the
mounting aye~l~e5 50 co~ r,ond to and ~cgisler with the bolt holes on
an ~csori~ted moldboard to allow the bolts to be threaded on and
secured.
In most blade call~ing vehicles and in particular in snow
removal vehi~ there are two standard sizes of moldboards that are
- 8 - 21109 ~9
common. These sizes include ones that are 11 feet long and ones that
are 12 feet long. The pre~erled form of blade body 12 is either 44 or 48
inches long. Thus three 48 inch long sections will cover a 12 foot long
mold board and three 44 inch long seg~ nts will cover an 11 foot long
5 moldboard. As will be appreciated by those skilled in the art the usual
form of attachment holes 50 on the moldboards themselves are in the
form of the first holes being located two hches from the side edge and
thereafter the holes are typically on four hch c~nlles. By utilizing the
universal hole ~allell, shown in Figure 3, it is possible to mount any of
10 the three blade se~rnPnt~ which are used to make a complete blade onto
either the end or the mi~ of the moldboard. This is desirable because
the wear patL~:ll, bet~e~l, the three blade se~m~ntC is not uniforrn. In
particular the æ~rnent riding over the crown of the road tends to wear
out first, and thus the life of the wear lesis~ t edge can be extended by
15 removing and ~it.l-il-g the segments around. For example the
se~m~nt at one end of the moldboard can be moved to the middle, the
one in the middle moved to the other end and the one at the other end
moved to replace the first end.
Turning now to Figure 9, one embodiment of the
2 0 ir ~el.lion can now be æen. This is a sectioT- through lines 9-9 of Figure
1 showing the two wear re~ict~nt blade edges, shown generally as 90 and
92. Wear resistant el~me~ts are shown in dotted outline at 94, 96
lc~e~ively. These are elements of the bull-nose type. Also shown are
two atPchm~nt holes 98, 100 through which attachment bolts may be
25 il.s_.ted. It will be a~r~ te~l that when a bolt is in~Pll~ in the bolt
hole 98, this pres~ls the edge 92 to the road or other surface being
worked. Cc,n.,e,æly, when a bolt is in~plle~ through bolt hole 100, edge
90 is ~l~s~ to the surface to be wol~ed. The distance from the
centreline C of the bolt hole to the respective edge is shown as D in
30 Figure 9. D is the same for each pair 90,100 and 92, 98, allowing the
blade to be fully and easily r~ le.
9 21109~
In the configuration of Figure 9 the bolt holes 50 face in the
same direction as each other. Thus to present a fresh working edge after
the first working edge is worn simply requires reversing the blade
upside down. In the embodiment of Figure 10, the bolt holes are formed
5 in opposite faces of the blade. This has some advantages. ~or example,
the holes may be formed on a drill press and milled after. Thus, by
working opposite sides of the blade body 12, less deformation of the body
results be~duse the stresses are in the op~osile direction. However, these
sllesses are not that signifi- ~nt
Thus, the most ~refelled embodiment is to have the bolt
holes forrned and counlels-mk in the same face. Firstly, the blade body
12 is a little easier to m~nllf~ re~ since there is no need to flip over the
blade between ~lrillirlg steps to mill o~posile faces. Secondly, for
trapezoidal shaped wear elPm~nt~ or other wear elements having sloped
15 edges such that one side of the blade extends up the side of the wear
elem~nt further than the other (see Figures 6 and 7), the higher
extending side will act as a shield to ~rolect the wear element from any
gl~n~ ing imp~ctc or blows that might otherwise cause a fracture of the
brittle wear resislant material. Such blows might be caused for example
2 0 by objects loosened from the surface being worked. The working edge
can and will cause objects to fly up into cont~ct with the other edge.
It will be appreciated that the edge 20, 22 that is mou,.led
ylj7.-~nt to the ground or the surface to be worked becomes the working
edge, and that by using the ~lt~rn~te row of bolt holes 51, 53 the other
2 5 edge 20, 22 can be made the working edge. Thus the ~ nt ill-/e~.lion
co~le;~ lates mounting the blade 10, for example, in a first position
where one of the wear ~ ..t edges 20 is in cont~ct with the s~lrf~ce to
be ~ol~;ed (and is the ~Ol~g edge) and a second position in which the
other wear ~esisldl-l edge 22 is in cont~rt with the surface to be worked.
3 0 The advantages of this construction can now be
a~l.r~i~terl In particular the blade 10 will have twice the wear life of a
2110949
- 10 -
conventional blade having one wear resistant edge. In other words the
amount of waste generated on the disposal of this blade is exactly half of
that with one wear resistant edged blades. In addition to being less
wasteful considerable energy savings are re~li7e~ because the amount of
5 steel that has to be shipped is also cut in half, reducing transportation
energy used not to mention the amount of energy saved which is used
to forrn the steel in the first place.
A f~ el advantage of this i lv~lllion is that different wear
resistant elements may be used on the same blade, along opposite edges
10 20, 22. Thus if the work to be performed changes, rather than having to
return to the shop to be fitted with new blades, the blade 10 can be
sirnply l~v~,æd in the field. Thus greaLe, flexibility of ~.alion of the
vehicle is achieved, without the need to carry extra blades or the like
which is impractical for current vehicle designs.
Turning now to Figure 11 a ~refelled extended design
according to the present illv~llLion is shown. In this design the blade
still includes wear resistant inserts which form upper and lower edges
20, 22, but rather than two rows of at~ hmPl t holes 51, 53 there is only
one row 102. Thus the ~licpnce from the centreline of the row of bolt
20 holes 102 to the wear resisl~lt edges 20, 22, shown as D, is identical to
each of the top edge 20 and the bottom edge 22. This results in a slightly
higher blade than in the t~P~igns of figures 9 and 10, because the height of
the blade is 2D, as opposed to being equal to 2D less the distance between
the rows of bolt holes 51, 53. This ~ltpm~te design is useful because the
2 5 cost of the ~ itio~ steel re.l.~iled to make the blade body with a E;leal~l
height is offset by the reduced cost of making the blade because only one
row of bolt holes is required.
In this regart it will be a~le~ le~1 by those skilled in the
art that the overall blade height cannot be made too small. Once the
3 0 wear ~SiSlalll edge is worn away, then the blade body itself can become
worn very quickly since even carbon steel is much less able to resist
- 11 21109 49
abrasion wear than the tungsten carbide inserts 30. Thus operators need
to pay careful attention to the state of wear in their blades in order to
~l~Vent the blade body from being substantially worn. Where there are
two rows of attachment holes 50, this means that there must be
5 sllffi~iPnt space between the top of the wear resistant inserts and the
bottom of the bolt holes 50 that the blade is not worn through to the
holes. If that were to occur, the mounting of the blade onto the
moldboard could be seriously compromised. One inch generally
provides enough clearance, but depending upon the conditions and the
10 operator, more than one inch may be desired. This may be the case
where the operator has to clear snow from vast remote sl-elches of
hardtop where there are not many eh~nces to turn around when blade
wear develops. Thus, the PxtPn~e~ design shown in Pigure 11 is in
some cases ple~l~ed.
It will be a~re~ te-l by those skilled in the art that while
rerer~:nce to ~refelled embo-limPnt~ have been made in the foregoing
descAption vaAations can be made without departing from the broad
scope of the Ll~v~llion as defined in the attached ~ l~im~. Some of these
variations have been discussed above and others will be apparent to
20 those skillP~ in the art. For example, many differ~nt styles of wear
resistant insert can be installed to suit customer ~lefel~l~ce and the
intended use.
