GB2065749A - Grader - Google Patents

Abstract

A land grader for towing as a trailer behind a tractor comprises a horizontal frame 1 to the underside of which is transversely mounted a scraper blade. The frame has a tractor hitching arrangement at the front end and at the rear end is provided with a pair of depending arms 8 each of which carries a land wheel 9. The arms are connected to the ends of an axle 6 journalled in the frame. The axle may be rotated by a hydraulic ram 12 to alter the angular position of the arms relative to the frame so as to adjust the height of the blade. In one embodiment the blade may be rotated in a horizontal plane relative to the longitudinal axis of the frame and may also be canted in a vertical axis. <IMAGE>

Description

SPECIFICATION Improved land grader This invention concerns a grading appliance for levelling or preparing a relatively smooth road or land surface, herein referred to as a "land grader".

An object of this invention is to provide an improved land grading appliance of simple but robust construction which may be attached to an agricultural tractor in the same manner as a trailer, and which will not be of complicated or costly construction but will be easy to operate to produce the graded land surface desired.

Accordingly the invention provides a land grading appliance which is towable as a trailer behind an agricultural tractor comprising a substantially horizontal frame to the underside of which is mounted a transverse scraping blade, the frame having at one end means for attachment of the appliance to a tractor, and at the opposite end a pair of depending arms pivotably connected to the frame and each arm carrying a land wheel, and means for adjusting the angular position of the depending arms relative to the frame whereby the height of the blade relative to the land surface to be graded may be altered.Preferably, the arms are connected to opposite ends of a transverse axle journalled in the frame, a crank is attached at one end to the axle intermediate its length and at the other end is pivotally connected to the piston rod of a hydraulic cylinder which in turn is pivotally connected to the frame.

In use the land wheels may be raised or lowered by the operation of the hydraulic cylinder thereby raising or lowering the blade relatively to the surface of the land below the blade, but there is complete rigidity between the blade and the end of the frame connected to the tractor tow-bar.

Preferably, the blade is pivotally mounted to the underside of the frame so that the blade may be rotated into a number of different angular positions relative to the longitudinal axis of the frame.

The frame advantageously consists of a pair of longitudinal members having at each end a transverse member and a further transverse member approximately midway between said end members, the end of the frame being forwardly extended for attachment to the tractor. The frame may consist wholly or mainly of rolled channel sections.

For the attachment of the blade to the frame a plate is provided extending transversely of the frame adjacent to the intermediate frame member, a number of struts or brackets extending obliquely downwards from the plate to the lower part of the blade, which latter may be stiffened by angle members or the like welded to the back of the blade and conforming to the curvature thereof.

The plate supporting the blade may be welded to the frame, but is preferably bolted to the frame, the latter arrangement enabling the angle of the blade relatively to the longitudinal centre-line of the frame to be adjusted, for example by the provision of a number of alternative bolt-holes in the plate to allow a number of alternative angular setting positions of the blade.

Two embodiments of the grading appliance are shown more or less diagrammatically in the accompanying drawings, wherein: Figure 1 is a side elevation of a first embodiment of the grading appliance.

Figure 2 is a plan view of the grading appliance shown in Figure 1.

Figure 3 is a plan view of a second embodiment of the grading appliance.

Figure 4 is a perspective exploded view of a detail of the grading appliance shown in Figure 3.

Referring to Figures 1 and 2 of the drawings, the frame of the appliance consists of longitudinal channel members 1, connected by transverse channel members 2, 3, 4 and forwardly extended to provide attachment means 5 convenient for connection to the tow-bar of a tractor (not shown) of any conventional construction. Towards the rear end of the frame an axle 6 is journalled in bearings 7 secured to the frame members 1, 1.

The axle 6 projects beyond the frame members 1 on both sides and carries at each end an arm 8 on which is rotatably mounted a land wheel 9. Also rigidly mounted on the axle 6 are a pair of bracket arms 10 between which is pivoted the outer end of the piston rod 11 of a hydraulic cylinder 12 pivoted in trunnion bearings 13 welded to the intermediate transverse frame member 3.

Below the frame member 3 is disposed a transverse plate 14 the ends of which extend beneath the frame members 1 at each side. The plate 14 may be welded to the frame members 1 and 3 or it may be adjustable secured thereto as described by way of example below. The the plate 14 is welded a grading blade 1 5. This is preferably of concave form on the side facing the front of the appliance. It is strengthened by angle or Tmembers 16 conforming to the curved shape and its rigidity is reinforced by struts 1 7 welded to the blade and to the plate 14.

Instead of being welded or simply bolted to the members 1, and 3, the plate 14 may be mounted so as to be angularly adjustable. A simple construction is shown which consists in forming the plate 14 with an arcuately arranged series of bolt-holes 19 diametrically opposite pairs of which may be employed to bolt the plate 14 to the frame members 1 by a bolt 20 passed through a selected pair of the bolt-holes 19. Preferably, with this arrangement the plate 14 is pivotally mounted at its mid-point to an intermediate frame member by means of a suitable pivot pin, so that the plate as a whole can rotate to bring a selected pair of boltholes 19 into register with a corresponding pair of bolt-holes in the frame members 1. In this way the angular portion of the blade 1 5 relative to the centre-line of the appliance may be selected within practical limits as desired.

A second embodiment of the grading appliance is shown in Figures 3 and 4. The blade 15 is suspended from a first cruciform frame 30 which is pivotally connected to a transverse member 31 of the frame intermediate of the transverse members 3,4. The pivot 32 is located in the middle of the transverse member 31. Rigidly fixed to the upper edge of the blade 15 is a second cruciform frame 33, by which the blade 1 5 may be suspended from the first cruciform frame 30.

As shown in Figure 4, the blade assembly, consisting of the blade 1 5 and the frame 33, may be tilted at an angle to the frame 30 and held rigidly in a tilted position by means of a pin and slot arrangement 34. Downturned brackets 35 on the frame 33 engage into depending brackets 36 on the frame 30, and a pin 37 may be passed through corresponding slots 38 in each of the brackets 35, 36' to rigidly hold the blade assembly in the desired position with respect to the frame 30. It should be noted that when the pins 37 are removed from the slots 38, the blade assembly is still attached to the frame 30 by means of a hinge arrangement 39. This arrangement consists of two pairs of bearings 40 depending from the frame 30, which engage over two pairs of upstanding bearings 41 on the frame 33, such that the frame 33 may be journalled about a pair of axial rods 42 passing therebetween.

Pins are thought preferable to bolts for ease of adjustment in the field. The blade 1 5 may be rotated with respect to the frame of the appliance about the pivot 32 and held rigidly in one of three positions in relation to the direction of travel, namely two positions 450 and a third position perpendicular to the direction of travel. Pins 20 passed through two selected pairs of diametrically opposite holes 43 in corner members 44 or in transverse members 3, 31, 44 of the frame of the appliance, may be employed to hold rigidly the frame 30, and thus the blade assembly, to the frame of the appliance in any one of the three positions already mentioned, although adaptations may be made to provide for more than three positions. The frame 30 has holes 45 adjacent the ends thereof which correspond to the holes 43.

Bracket members 47 located at the extrernities of the frame 30 act as guide plates which engage with the frame to prevent rocking of the blade assembly.

In operation the grading appliance is hitched to a tractor vehicle and the height of the blade 1 5 relatively to the land surface to be graded may be suitably adjusted by adjusting the angular position of the arms 8 and therewith the land wheels 9 by operation of the hydraulic cylinder 12. The wheels 9 in a raised position are indicated by broken lines 9a in Figure 1. They may also be lowered, as indicated by broken lines 9b, for example when it is desired to raise the blade 1 5 clear of the ground surface. The position of the wheels may be adjusted, if desired, when the appliance is in operation, the lines supplying hydraulic pressure to the cylinder 12 being controllable from the tractor.

Adjustable stop means may, however, be provided to limit positively the range of adjustment of the wheels 9. Such stop means may advantageously comprise an abutment arm 21 on the axle 6 co-operating with an adjustable stop, for example a screw mounted on one of the frame members. An alternative from of adjustable stop is shown in Figure 1 consisting of a cam member 22 against which the arm 21 may rest, the cam being pivoted to the frame member 1 and adapted to be locked in its desired adjusted position by means of a locking bolt 23 passing through the web of the frame member 1, and through an arcuate slot 24 in the cam 22. Other arrangements of adjustable stop means are obviously possible.

For example, as shown in the embodiment of Figure 3, the pair of bracket arms 10 are extended so as to act as a crank which abuts against the frame member 2 when the piston of the hydraulic cylinder is retracted. To restrict the downward movement of the wheels 9, a screw 46 is mounted between the bracket arms 10 on the frame member 2 which is conveniently located forwardly of the axle 6. The upper surface of the bracket arms 10 abuts the head of the screw 46 when the piston is extended.

The invention thus provides a simple construction of land grading appliance which is adapted to be towed by a tractor and which may be very easily adjusted to suit the nature of the surface to be graded and the preferred height at which the grading blade may most advantageously operate. By tilting the blade from a horizontal plane, a camber may be produced on the surface to be graded.

Instead of the arrangement shown in the drawings where the wheel-carrying arms 8 are attached to the end of axle 6 journalled for rotation in the frame, the arms 8 themselves could each be independently pivotally connected to the frame and each being operated by a separate hydraulic ram. In this way the angular position of each arm 8 relative to the frame may be independently adjusted so as to cant the frame, and thus the blade, to the horizontal. In another arrangement the rotation and tilting of the blade of the embodiment of Figure 3 may be carried out by means of hydraulic rams in well known manner.

Claims (12)

1. A land grading appliance which is towable as a trailer behind an agricultural tractor comprising a substantially horizontal frame to the underside of which is mounted a transverse scraping blade, the frame having at one end means for attachment of the appliance to a tractor, and at the opposite end a pair of depending arms pivotably connected to the frame and each arm carrying a land wheel, and means for adjusting the angular position of the depending arms relative to the frame whereby the height of the blade relative to the land surface to be graded may be altered.

2. A hand grading appliance as claimed in claim 1 wherein the arms are connected to opposite ends of a transverse axle journalled in the frame, a crank is attached to one end of the axle intermediate its length and at the other end is pivotally connected to the piston rod of a hydraulic cylinder which in turn is pivotally connected to the frame.

3. A land grading appliance as claimed in claim 1 wherein means are provided for rigidly holding the blade in a substantially horizontal plane at a selected position.

4. A land grading appliance as claimed in claim 3, wherein the blade is both pivotally connected to and suspendably attached to the frame such that the blade may be tilted from a substantially horizontal plane by adjusting the angle at which the blade is suspendably attached to the frame.

5. A land grading appliance as claimed in claim 4, wherein the blade is both pivotally connected to and suspendably attached to the frame by means of a frame member between the frame and the blade, which frame member is pivotably connected to the frame while the blade is suspendably attached to the said frame member.

6. A land grading appliance as claimed in claim 5, wherein the blade is suspendably attached to the frame member by means of a hinge arrangement allowing the blade to be tilted from a substantially horizontal plane, and further means being provided for rigidly holding the blade at a selected angle.

7. A land grading appliance as claimed in claim 6, wherein the said further means comprises a pin and slot arrangement between the blade and the frame member.

8. A land grading appliance as claimed in claim 3, wherein the means for rigidly holding the blade in a substantially horizontal plane comprises a plate fixed to the blade having two arcuately arranged series of holes about the point of pivotal connection, such that any two diametrically opposite holes may be employed for bolting the plate and the blade therewith to the frame at the said selected position.

9. A land grading appliance according to claim 5 wherein the frame member is of cruciform shape, and is adapted to be bolted to the frame such that the frame member and the blade therewith are held rigidly in a selected position with respect to the frame.

10. A land grading appliance according to claim 1, wherein stop means are provided to limit positively the range of adjustment of the angular position of the depending arms and therewith the land wheels.

11. A land grading appliance substantially as described herein with reference to Figures 1 and 2 of the accompanying drawings.

12. A land grading appliance substantially as described herein with reference to Figures 3 and 4 of the accompanying drawings.