CA1052566A - Device for high lift setting of the grader blade of a road grader - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
The pivotable arms supporting the lift cylinders for a road grader blade are connected to support brackets on the grader frame by means of pivotal joints lockable by remote control. A joint comprises a bolt extending through the arm and bracket and engaging one of these elements with the bolt head. Between the other element and a nut on the opposite end of the bolt annular compression strings are arranged which clamp the arm and bracket together. A cylinder encloses the bolt end with nut and springs and an annular piston is arranged between the nut and the springs. The piston is freely movable on the bolt and when the space above the piston is pressurized, the piston compresses the springs, thereby relieving the clamping force and allowing relative rotation of the arm and bracket.

Description

lOS'~S~;6 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 iOS;~566 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.

~OS;~S~6 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 lOSi~5f~;
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 105'~5~
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 lOSZ5t;6 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 lOS;Z5tj6 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 105Z5~6 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.

Claims (9)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A device for angular setting of a grader blade of a road grader, wherein the grader blade is supported by two lift cylinders, each of which is pivotably connected to a pivotal arm which extends laterally out from a support bracket on the frame of the grader and which is pivotably connected to the same by means of a pivotal joint which is lockable and releas-able by means of remote control, characterized in that the pivotal joint is constructed as a clamping mechanism and com-prises a tension member which is retained by the first one of the two elements formed by the arm and the bracket, that the tension member extends freely to the side of the second element which is facing away from the first element and is provided with a tension-absorbing head outside of said side of the second element; that a compression spring is located between the second element and the head and thereby clamps the elements against each other, that a piston-cylinder arrangement is arranged with the piston being movable in the longitudinal direction of the ten-sion member and a cylinder space connectible to a source of pressurized medium; and that the piston-cylinder arrangement is arranged to compress the spring when pressurized medium is supplied to the cylinder space and thereby remove the clamping force between the two elements.

2. A device according to claim 1, characterized in that a third support bracket is arranged below the frame of the road grader; that a third arm is pivotably connected to the third bracket by means of a third clamping mechanism and supports a third blade control cylinder which extends essentially transversely beneath the frame in the horizontal position of the grader blade.

3. A device according to claim 2, characterized in that the outer end of the piston rod of the third blade control cylinder is connected by means of a ball and socket joint to a transverse beam of the circle which supports the grader blade, and that the ball and socket joint is movable in a longitudinal groove in the transverse beam and removably lockable in a desired position in said groove.

4. A device according to claim 1, characterized in that a cylinder member abuts the second element and surrounds the head of the tension member and the spring; that the end of the cylinder member which is facing away from the second element is closed and forms said cylinder space; and that the piston is arranged between the spring and the tension member head in the form of an annular piston movable on the tension member.

5. A device according to claim 4, characterized in that the tension member has a stop which is situated at a distance from the piston when no pressure prevails in the cylinder space, against which stop the piston will abut when the cylinder space is pressurized so as to move the tension member through the second element.

6. A device according to claim 1, characterized in that the piston-cylinder arrangement is situated between the two elements.

7. A device according to claim 6, characterized in that the cylinder space is formed by a bore in the first element and that, in the event of pressurization of the cylinder space, the piston directly influences the second element.

8. A device according to any of claims 1, 4 or 6, char-acterized in that the two facing surfaces of the two elements have cooperating projections and recesses such as radial ribs and grooves which, when the elements are pulled together, prevent relative rotation of the same.

9. A device according to claim 1, wherein the tension member abuts the side of the first element facing away from the second of said elements.