Note: Descriptions are shown in the official language in which they were submitted.
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This application is divided out of copending Canadian application
No. 271,948 filed February 17, 1977.
Motor graders have a longitudinal main frame which has a
dirigible wheel assembly at its forward end, an operator's cab at its rear-
ward end portion, and a traction chassis for the motor and power train behind
the cab. The motor grader blade is suspended from the main frame by means
of a circle draw bar and a circle. The circle draw bar has its front end
connected to the front of the main frame by a ball and socket connection,
while the rearward portion of the circle draw bar is suspended from the main
frame by hydraulic cylinder and piston means which permit the draw bar to
swing in a vertical plane about its front end.
The circle is mounted on the rearward portion of the circle draw
bar for rotation about a vertical axis, and there is a driving interconnection
between a motor on the circle draw bar and a ring gear on the circle to effect
such rotary motion of the circle.
~ he grader blade is mounted upon the circle so that rotation of
the circle changes the angle of the blade with reference to the path of
travel of the grader, while swinging the circle draw bar in a vertical plane
about its forward end changes the vertical position of the grader blade with
reference to the ground.
In addition, the grader blade is mounted on a horizontal axis so
that it may be tipped with respect to the circle by hydraulic cylinder and
piston means ~o change the angle of attack of the blade and it may also be
shifted endwise in its mounting.
U. S. Patents 2,799,099 and 3,191,324 disclose typical prior art
motor grader blade assemblies.
Prior art motor grader blade assemblies are subject to inordinate
damage at the lower corners of the moldboard and the blade; the lower edges
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of prior art moldboards and the replaceable blade have been known to bend;
and in addition there have been instances of the entire blade assembly being
warped or twisted from end to end.
The principal object of the present invention is to provide an
improved blade assembly for a motor grader.
According to the present invention there is provided a motor
grader blade assembly comprising, in combination: an elongate moldboard
which is forwardly concave and has upper and lower margins; a replaceable
cutting blade mounted on the front of said moldboard and projecting a short
distance below said lower margin; unitary longitudinally extending moldboard
reinforcing means extending from immediately adjacent said lower margin to a
plane near said upper margin and terminating close to the ends of the mold-
board; lower corner reinforcing members welded to, and extending laterally
outwardly from the ends of the lowermost part of said unitary reinforcing
means effectively to the ends of the moldboard immediately adjacent the mold-
board lower margin; and upper and lower support rails integral, respectively
with the uppermost and lowermost parts of said unitary reinforcing means.
In the accompanying drawings:-
Figure 1 is a side elevational view of a motor grader embodying20 the invention;
Figure 2 is a perspective view of a subassembly consisting of a
circle mounting bar, a circle, and a grader blade assembly which embodies
the present invention;
Figure 3 is a vertical, sectional view on an enlarged scale taken
substantially as indicated along the line III-III of Figure 2;
Figure 4 is a fragmentary rear elevational view on a scale
smaller than Figure 3, illustrating the left hand end portion of the assembly
as illustrated in Figure 2; and
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Figure 5 is a fragmentary longitudinal sectional view taken sub-
stantially as indicated along the line V-V of Figure 4.
Referring irst to Figure 1 of the drawings, a motor grader,
indicated generally at 10, includes a longitudinal main frame 11 the front
end lla of which is supported upon a dirigible front wheel assembly 12, and
the rear end of which constitutes part of a traction chassis, indicated
generally at 13, on which is mounted a power plant, indicated generally at
14. An operator's cab, indicated generally at 15, is on the rear portion of
the main frame, forward to the traction chassis. A grader blade subassembly,
indicated generally at 16, consists generally of a circle mounting bar,
indicated generally at 17, which in the illustrated apparatus is a draw bar;
a circle structure, indicated generally at 18; and a grader blade and blade
mounting, indicated generally at 19.
The circle draw bar 1~ is best seen in Figure 2 to include a
forward beam, indicated generally at 20, and a rearward circle carrying
structure, indicated generally at 21, the forward part 22 of which is integral
with the rear end of the beam 20. Behind the part 22 of the carrying structure
said carrying portion has a section 23 the depth of which is great enought
that it forms a housing extending below the circle 18. The housing section
23 receives drive means, indicated generally at 24. The housing section 23
of the circle draw bar merges into a nearly semi-annular upright wall 25
which is part of an internal housing for the circle 18, and integral with the
wall 25 is a horizontal top wall 26.
The subassembly 16 is mounted under the main frame 11 by means of
a front mounting element and rear mounting elements which engage with co-
operating elements carried upon the main frame. At the front end 20a of the
circle draw bar is ~ ball 28 which forms part of a ball and socket connection
(not shown) by means of which the front of the circle draw bar is connected
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for universal movement on the front end lla of the main frame. At the
back end of the housing section 23 of the rearward circle draw bar portion 21
is a pair of aligned,, laterally extending upright plates 29 which are
provided with balls 30 that make ball and socket connections with fittings
(not shown) on the lower ends of a pair of hydraulic cylinder and piston
units 30a which are carried upon the main frame 11. Thus, operation of the
hydraulic cylinder units 30a swings the circle draw bar 17 about the ball and
socket connection including the ball 28, which in this respect provides a
horizontal pivot axis. A ball 30b on one of the webs 29 provides for a ball
and socket connection with a side-shift cylinder (not shol~) which shifts
the draw bar sideways, with the ball 28 providing a vertical pivot axis.
Referring now to Figures 3 to 5, the motor grader blade and blade
mounting 19 consists of a blade assembly, indicated generally at 31, which
is carried in a pair of support arms 32 which are structurally integral with
the circle structure 18. The blade assembly 31 includes an elongate mold-
board member 33 the lateral extremities 34 of which are seen in Figure 5 to
be offset rearwardly, and in addition the lower marginal portion 35 of the
moldboard member is also seen to be offset rearwardly.
The grader blade assembly 31 also includes reinforcing means,
indicated generally at 36, which consists of an upper channel-like member 37
having upper and lower webs 38 and 39 connected by a rear web 40, with the
upper and lower webs being welded to the rear of the moldboard as indicated
at 41 and 42. A lower channel-like member 43 has an upper web 44, a lower
web 45, and a rear web 46. The upper web 44 of the channel-like member 43
is welded to the rear of the moldboard member at 47, while the lower web 45
is welded at 48 to the upper, rear extremity of a longitudinal, lower re-
inforcing melDber 4Y which is welded to the moldboard at 50 and 51. A
reinforcing plate 52 is welded at 53 and 54 along rearward portions of the
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respective channel members 37 and 43 so that the moldboard 33, the channel-
like members 37 and 43, and the reinforcing plate 52 define a box-like
structural member which is indicated generally at 55. A series of laterally
spaced vertical ribs, such as the rib 56 seen in Figures 3 and 5, are
spaced along the moldboard 33 and the reinforcing plate 52 and bear upon both
of them. These, together with the longitudinal internal support provided by
the webs 39 and 44 of the channel-like members 37 and 43, provide internal
reinforcement for the box-like structural member 55.
A replaceable cutting blade 57 is secured to the offset lower
marginal portion 35 of the moldboard member 33 by means of a line of bol*s
such as the bolts 58 seen in Figures 3 and 4, and the heads of said bolts are
positioned in downwardly open recesses 59 which are formed in the lower
longitudinal reinforcing member 49.
As best seen in Figure 5, each of the rearwardly offset end
portions 34 of the moldboard member 33 carries a shim 60, and an end blade
61 is secured to the shim and to the offset end portion 34 of the moldboard
by means of screws and nuts 62.
Also at each end of the blade assembly 31 are corner reinforcing
members such as the member 63 seen in Figures 4 and 5, and said members have
inner ends 64 which cooperate with plates 65 to close the ends of the box-
like structural member 55; and the corner reinforcing members 63 are bi-
furcated to accommodate one of the bolts and nuts 62 by means of which the
end blades 61 and shims 60 are fastened to the moldboard.
Upper and lower blade assembly support rails 66 and 67, respectively,
are respectively welded to the rear webs 40 and 46 of the upper and lower
channel-like members 37 and 43 and support the blade assembly in the mounting
be~ls 32 for ~ndwise adjustment as is usual in motor grader structures.
The lower rail 67 is seen in Figure 3 to have a lower margin 68
parts of which are in a common plane with the lower web 45 of the lower
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channel-like member and with the lower surface 49a of the reinforcing member
49 and all are substantially aligned with the lower margin of the moldboard
for direct transmittal of vertical working forces into the lower rail 67.
The lower rail 67 has a large planar top surfaces 69, and both said
rail and the upper rail 66 have large, planar rear surfaces 70 and 71,
respectively. Such surfaces act to distribute vertical and horizontal
working forces.
