Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to a device according to
the preamble of claim 1 for angular or high lift setting of
the grader blade of a road grader.
Such a device is known by, for example, U.S. Patent
Specification 39038,268. In said device the pivotal joints by
means of which the pivotal arms are connected to the sup~ort
brackets on the ~rader frame are provided with discs lying
adjacent to the arms, said discs being provided with holes
arranged in a circular arc. A remote-controlled loc ~ng pin
is passed through one of said holes and a hole in the pivotal
arm in order to lock the arm in a desired an~ular position.
This device has three essential disadvantages. The first is
that the positioning possibilities for the pivotal arm are
restricted by the limited number of holes in the hole disc.
The second is that the hole disc is oriented transverse the
blade frame and, thus, obstructs the driver's view. Said
first disadvantage can be eliminated by means of the hole
discs being provided with more holes havin~ smaller mutual
angular distance. However, in order to make this possible,
the holes must be moved out further away from the pivotal
axis, whereby the hole disc must be larger and, thus, causes
even poorer visibility.
Thirdly, it has been found that the holes in the hole
disc and the arm wear rapidly so that play arises. The
positioning of the grader blade is then altered in an
uncontrollable manner during operation. This leads to
impaired working precision.
The purpose of the present invention is to eliminate
all of said disadvantages.
According to the invention, this is achieved by means
of the pivotal device mentioned above being provided with
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the characteristics disclosed in claim 1. The pivotal ~oint
included in the device functions as a clamping mechanism and
allows totally arbitrary angular setting of the pivotal arms.
No play can arise as a result of worn locking holes.
Furthermore, the main dimension of the pivotal joint can ~e
arranged in the longitudinal direction of the blade frame so
that the joint is transversely narrow and less visibility-
inhibiting than previously known lookable joints.
The invention is described in more detail below with
reference to the accompanyin~ drawings, in which Figs. 1 and
2 are an axial cross section and end view, respectively, of
a pivotal joint for the pivotal arm and arm support bracket
of a road grader, Figs. 3 5 are transverse sections of the
frame of the road grader in which the grader blade is
situated in different positions, and Fig. 6 is an axial
section of a modification of the pivotal joint shown in Fig. 1.
The pivotal joint constructed as a clamping mechanism
and shown in Fig. 1 comprises a bolt 1 which passes through
a bore 2 in the only partially shown pivotal arm 4 for a
blade lift cylinder of a road grader. The bolt 1 also passes
through a bore 3 in the bracket 5 connected to the frame 6 of
the road grader. The head 7 of the bolt 1 abuts the bottom
side of the arm 4 via a washer 8. The cylindricaI bolt head
7 is axially movable in a bore 9 in a supporting frame 10
welded onto the grader frame 6.
The opposite end 11 of the bolt 1 has a smaller
diameter and is provided with a threading onto which a nut 12
is screwed. The washer 13 abuts a piston 14 whieh, by means
of a central bore 15, is axially slidably guided on the
narrower portion 11 of the bolt. A number of annular springs
16 and a washer 17 are arranged between the piston 14 and the
bracket 5.
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The outer and inner edges of the piston 14 are
provided with annular grooves 18,19 in wh;ch rubber sealing
rings 20 and 21, respectively, are arranged. The sealing
rings 20,21 engage the bolt 1 and the inside of a cylindrical
tube 22, respectively, a foot 23 of said tube 22 abutting the
free surface of the bracket S. The opposite end of the
cylindrical tube 22 is sealed by means of a square end plate
24. Holes (not shown here) for screws 25 are arranged in the
corners of the end plate which are situated outside of the
cylindrical tube 22, said screws 2S extending down to and
bein~ screwed into threaded bores 26 in the bracket 5; cf.
Fig. 3; whereby the end plate 24, and therewith the
cylindrical tube 22, can be clamped to the bracket 5. The end
plate 24 has an aperture 27 having a connection 28 by means
of which the cvlinder chamber 29 formed between the end plate
24 and the piston 14 can be connected to a source of
pressurized medium, for example hydraulic oil or pressurized
air.
Figs. 1 and 2 show the clamping mechanism according to
the invention when atmospheric pressure prevails in the
cylinder chamber 29. The cvlinder chamber formed bet~leen the
piston 14 and the bracket 5 is vented in a manner not shown
here. The tension in the bolt which is imposed bv means of
turning the nut 12 is transferred from the nut 12 to the
bracket S via the annular sprin~s 16 which maintain desired
clamping force between the arm 4 and the bracket 5. When the
high lift setting of the grader blade in the transverse
dire~tion of the grader is ~o be altered, it is desirable to
alter the angular position of the arm 4 and thereafter relock
the same. The locking force achieved by the nut 12 and the
annular springs 16 can be used to, by means of friction
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between the facing surfaces of the arm 4 and the hracket 5,
connect the same non-rotatably to each other. In the embodi-
ment according to Figs. 1 and 2~ however, the facing surfaces
of the arm 4 and the bracket 5 are provided with mutually
cooperating radial ribs and grooves in the form of teeth 3n
and 31, respectively which, by means of engaging with each
other, prevent pivoting of the arm 4. ~en the arm is to be
released for pivoting, pressurized medium is supplied to the
cylinder chamber 29 through the connection 28. The Pressure
leads the piston 14 and forces the same downwards in the
cylindrical tube 22, whereby the annular springs 16 are
further pressed together. ~o~^7ever, the pressure from the
annular springs 16 is now absorbed b~J the screws 25 screwed
into the bracket 5 and is not transferred to the arm 4. Thus
the tension in the bolt 1 ceases, and in those cases in which
only frictional engagement exists between the members 4 an~
5, said members can be directlv rotated with respect to each
other. In the embodiment shown in Figs. 1 and 2, the piston
14, when moved downwards in the cvlindrical tube 22, will
abut the annular stop 32 which is formed between the thicker
and narrower (11) portions of the bolt 1. If the piston 14 is
moved further, it will thereafter also move the bolt 1 down-
wards in the drawing through the bore 3 in the bracket S,
whereby engagement between the teeth 31,30 of the bracket 5
and arm 4, respectively, will be released and the arm 4 can
be turned. I~hen the arm 4 has been swung to the desired
angular position, the cvlider chamber 29 is relieved, whereby
the annular sPrings 16 return the piston 14 to abutment with
the nut 12 and apply preset tension in the bolt 1.
Figs. 3-5 schematicallv show a transverse cross section
as seen from the rear of a road grader frame 6 having three
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support brackets for pivotable ar~s provided with clam,~ing
mechanism~ M according to Figs. 1 and 2. The left, right and
bottom sides of the frame 6 are provided with brackets Sa,
Sb and S~, respectively. An arm 4a, 4b and 4c, respectively,
is pivotably connected to a resDective bracket. The free ends
of each of the arms 4a,4b are each provided with a respective
joint 35a,35b, By means of these joints, the arms 4a,4b
support hydraulic blade lift cylinders 36a,36b, respectively.
The piston rods 37a,37b, respectively, of the cvlinders 36a,
36b are flexibly connected in a known mannex to a transverse
beam 39 of the draw bar (not shown here) of the road grader
by means of ball and socket joints 3~a~38b, respectivel~.
The draw bar and the trans~ erse beam 39 support the circle
40 of the grader, under which circle the grader blade 41 is
attached.
In the positi~n shown in Fig. 3 the grader blade 41 is
horizontal, the lift cylinders 36a,36b standing ~arallel with
each other, the piston rods 37a,b projectin~ out equally. The
lift cylinders 36a,b stand vertically when the grader blade
is situated centrally under the frame 6.
The free end of the pivotable arm 4c situated lon the
lower bracket 5c is provided with a joint 42 which pivotably
supports a hydraulic cvlinder 43, hereafter called hi~h lift
cylinder. The piston rod 44 of the high lift cylinder 43 is
connected to the right-hand portion of the transverse beam
39 by means of a ball and socket joint 45. In a manner not
shown here the ball and socket joint is arranged in a ~roove
46 running along the beam 39 so that the free end of the
piston rod 44, with the ball and socket joint 45, can be
moved along the transverse beam 39. The ball and socket
joint is locked in a desired position in the groove 46 by
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means of a clamping mechanism M essentiall~ constructed
according to Figs. 1 and 2.
When the grader blade 41 is to be swung from the
horizontal position shown in Fig. 3 to the left~hand vertical
position according to Fig. 4 (high lift setting), hydraulic
pressure is supplied to the clamping mechanisms M at brackets
Sa,5b and 5c: In this manner the pivotal arms 4a,4b and 4c
are released. By means of extending the piston rods 37a and
44 and drawing in piston rod 37b~ the arms 4a,b and c are
thereafter swung to the positions shown in Fig. 4. The
pivotal arms 4a,b and c are thereafter relocked by means of
relieving the hydraulic pressure in the clamping mechanism M.
Finally, the piston rods 37a and 44 are drawn in and piston
rod 37b is extended until the blade 41 assumes the vertical
position according to Fi~. 4. Return of the grader blade 41
to the horizontal position according to Fig. 3 is effected in
the inverted order.
When the grader blade 41 is to be swung from the
horizontal position shown in Fig. 4 to the right--hand
vertical position according to Fig. 5, one can proceed in
principally the same manner as described above. However, the
extension length of the piston rod 44 of the hi~h lift
cylinder 43 will then become so great that a telescopic
piston rod is reguired. This nosition is shown by dashes in
Fig. 5. In order to avoid the extra cost of a telescopic
piston rod., an arrangement having a longitudinal groove 46 in
the transverse beam 39 and a clamping mechanism M for
fastening ~he joint 45 at the desired position along groove
46 is used. Movement of the joint 45 from the position at the
right-hand end of the transverse beam 39 shown in Fig. 3 to
the position at the left-hand end of the transverse beam 39
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shown in Fig. 5 is effected successivelv with alternate
locking of the clamping mechanisms at the joint 45 and the
bracket 5c.
By means of the arrangement having clamping mechanisms
as shown in Figs. 3 5 it is posslble for the grader driver
to swing the grader blade out to the vertical position in
both directions by means of remote control. The clamPing
mechanisms M according to the invention allow rapid release
and locking of the Joint connections and make it possible to
lock the pivotal arms 4a,b~c in closelv ad~acent angular
~ositions, for example, with an angular difference of merel~
5. If an even finer setting of the arms 4a,b,c is desired,
the clamping mechanisms M can, as an alternative to the
embodiments shown in Figs. 1 and 2 having tooth engagements
30,31, be designed for pure frictional engagement, wherebv
the arms 4a,b,c are provided with stepless adjustability. In
both cases, the clampin~ mechanism M can be designed to be
compact so that it does not obstruct the driver~s view.
Fig. 6 shows an axial section similar to Fi~. 1 of a
clamping mechanism according to another embodiment of the
invention. Details having correspondence in Fig. 1 have been
provided with the same reference numerals in Fig. 6. The nut
12 screwed onto the bolt 1 directly abuts the sprlngs 16 via
the washer 13. A central circular recess or shallow bore 47
is arranged in the surface of the pivotal arm 4 which is
facing the bracket S, said bore 47 forming a cvlinder for a
piston 45 in the form of a disc which is axially movable on
the bolt 1. The cvlinder chamber 29 between the piston 48 and
the cylinder 47 is sealed by means of 0-rings 49,50 and 51
arranged in grooves in the piston 48 and the arm 4. The piston
48 influences the bracket 5 in a shallow recess 52 in said
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piston. Bv means of a bore in the bolt 1, the cylinder
chamber 29 is connected to the Pressurized medium connection
28 arranged in the end 11 of the bolt 1. ~en pressurized
medium is supplied to the chamber 29, the piston 48 forces
apart the arm 4 and the bracket 5 while forcing to~ether
annular sprin~s 16 so that tooth en~,agement 30,31 is released
and the arm 4 can be swung around the bolt 1. When the
pressure in the chamber 29 ceases, the sprin~s 16 return the
clamping mechanism M to the locking position. In Figs. 1,, 2
and 6 the cla7,nping mechanism M is shown having a bolt passing
through the same, said bolt being provided with a pressure
absorbing head in the form of a nut screwed onto the bolt. In
other uses the bolt can be replaced by a screw which is
screwed into the arm 4 and whose head abuts the piston 14.
Alternatively, in the e~bodiment accordin~ to Fig. 1
the piston can in itself be provided with threads and he
screwed onto the bolt as a nut, whereby there is no need for
a separate nut and washer. The clamping mechanism can be
inverted, that is, the arm 4 and the bracket 5 can exchange
positions.
