Abstract:
There is provided a disc unit for mounting a plurality of discs to an outer end of a mouldboard of a grader. The disc unit includes a mounting bracket for securing to a rear face of an outer end portion of the mouldboard. A frame is pivotally mounted on the mounting bracket and supports an axle which mounts the discs thereon. A hydraulic cylinder pivots the frame supporting the discs in relation to the mounting bracket for raising and lowering the discs to engage the ground at various depths of cut. A cushion valve releases the hydraulic cylinder in the case of an obstruction engaging the discs. The discs include a concave inner surface which are arranged to face towards the grader and partially in the direction of travel for urging particulate material away from the shoulder and towards a center of the road.

Description:
FIELD OF THE INVENTION 
     This invention relates to a disc unit for mounting on a mouldboard of a road grader and more particularly to a mouldboard mounted disc unit for recovering scattered gravel from a shoulder of a road for reuse on the road, 
     BACKGROUND 
     Often on gravel roads, the gravel is displaced to the sides of the road and collects over time along a shoulder of the road due to the passing of vehicles. This is undesirable as the road loses its covering while the shoulder of the road becomes dangerous to drive on as it is full of loose particles. 
     Devices have been used in an effort to redistribute gravel evenly across the surface of the road. These do not effectively reclaim the gravel that collects at the shoulder of the road. 
     U.S. Pat. No. 2,188,435 to Hargrave describes a disking device for use with a grader or other similar vehicle. The disking device comprises a plurality of discs axially aligned and mounted either in front or to the rear of the mouldboard of the grader for levelling and spreading earth and other particulate materials. The device is limited however to being centrally mounted beneath the grader. The device requires manual adjustment of the height of the discs in relation to the grader and manual adjustment of the depth of cut of the discs. 
     SUMMARY 
     According to the present invention there is provided a disc unit for collecting scattered particulate material from a shoulder of a road for reuse on the road when mounted on a road grader having a mouldboard extending transversely to a direction of travel of the road grader, the disc unit comprising: 
     a plurality of substantially parallel spaced apart discs; 
     a cutting edge about a periphery of each disc arranged to engage the shoulder; and 
     a frame mounting the discs thereon, the frame being arranged to be mounted rearwardly of the mouldboard at an end thereof, each disc being oriented on the frame at an angle extending forward towards and laterally outwards with respect to the mouldboard, the frame being movable between an engaged position wherein the discs engage the shoulder for digging up and urging the particulate material towards the centre Qf the road and a raised position wherein the discs are spaced upwardly from the shoulder such that the discs do not interfere with normal operation of the mouldboard of the grader. 
     Preferably the discs are mounted axially along a common axis. When the discs are mounted along the common axis, the common axis is preferably arranged at an angle to the rear face of the mouldboard wherein an inner end of the axis is nearer to the rear face of the mouldboard than an outer end of the axis such that the discs mounted along the axis extend at an angle to the rear face of the mouldboard for urging the particulate material towards the centre of the road. 
     It is preferred that there be provided pivotal mounting means mounting the frame rearwardly of the mouldboard such that the frame is pivotal between the raised position and the engaged position. 
     When using pivotal mounting means there may be provided hydraulic control means controlling pivotal motion of the frame in relation to the mouldboard such that the discs are positionable at any height relative to the shoulder within a given range. A pressure relief valve may be connected to the hydraulic control means such that pressure within the hydraulic control means is relieved in the event of a sudden blow on the discs from an obstruction on the road. 
     There may be provided mounting means mounting the frame to the mouldboard wherein the mounting means is arranged such that a height of the discs at an inner end of the frame is adjustable in relation to the height of the discs at an outer end of the frame for levelling the discs on a range of road inclinations. 
     Preferably each disc includes a concave inner surface facing forwards and towards the centre of the road in use such that the discs are arranged to cut into the shoulder of the road and urge the particulate material towards the centre of the road. 
     A mounting bracket may be provided mounting the frame on the mouldboard wherein the mounting bracket is arranged to mount on the rear face of the mouldboard. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings, which illustrate an exemplary embodiment of the present invention: 
     FIG. 1 is an isometric view of the mouldboard mounted disc unit in use mounted on a grader for levelling the shoulder of a road; 
     FIG. 2 is an enlarged isometric view of the mouldboard mounted disc unit as shown in FIG. 1; 
     FIG. 3 is an isometric view of the mouldboard mounted disc unit as it is seen from the cabin of the grader; and 
     FIG. 4 is a schematic of the hydraulic components of the grader connected with the mouldboard mounted disc unit showing an enlarged pressure relief valve. 
    
    
     DETAILED DESCRIPTION 
     Referring to the accompanying drawings, there is illustrated a mouldboard mounted disc unit generally indicated by the number  10 . The disc unit  10  mounts on a mouldboard  12  of a grader  14  for levelling the shoulder  16  of a road  18 . 
     The disc unit  10  includes a mounting bracket  20  having an inner side member  22  and an outer side member  23  for securing the unit to a rear face  24  of the mouldboard. A front edge  26  of each side member which lies adjacent to the rear face  24  of the mouldboard is arranged to conform to the rear face. The front edge  26  includes an upper flange  28  extending upwards from a top end  30  for engaging beneath a securing flange  32  extending rearwards and downwards from the rear face  24  of the mouldboard. Near a bottom end  34  of each side member, the side member includes a C-shaped sleeve portion  36  extending laterally therefrom and arranged to engage over a supporting rod  38  extending across the rear face of the mouldboard. A lower flange  40  extends laterally from the C-shaped sleeve portion of the outer side member  23  for bolting the bottom end  34  to an end  42  of the supporting rod. 
     A side flange  44  extends upwards from the top end  30  of the outer side member  23  for engaging an end  46  of the securing flange  32 . A lug  48  is mounted on the top end  30  of a rear edge  50  of the outer side member  23 . The lug  48  pivotally mounts a cylinder end  52  of a hydraulic cylinder  54 . 
     The inner and outer side members  22  and  23  are connected by a first cross member  56  mounted to each side member at the top end  30  and a second cross member  58  parallel and spaced from the first cross member. The second cross member  46  is mounted to each side member near the bottom end  34 . 
     At the bottom end  34  of the rear edge  50  of both the inner and outer side members is a pivot  60  mounting a respective end of a pivot plate  62 . The pivot plate  62  extends laterally outwards past the outer side member  23  at an outer end  64  of the pivot plate and past the inner side member  22  at an inner end  66  of the pivot plate. 
     A frame  68  mounts onto the pivot plate  62 . The frame  68  includes a front member  70  and a rear member  72 . The front member  70  is in the form of a plate similar in size and shape to the pivot plate and mounted adjacent to the pivot plate at both ends by a bolt  74  inserted through co-operating apertures  76  in both the pivot plate and the front member. At the outer end  64  of the pivot plate the bolt is fixed within the aperture for pivotal movement of the frame about the bolt at the outer end  64 . At the inner end  66  of the pivot plate, the aperture  76  is in the form of a vertical slot for vertically positioning the bolt therein and adjusting an angle between the frame and the pivotal mounting means. Variation of the angle of the frame  68  allows the disc unit to conform to a variety of road inclinations. 
     The rear member  72  is connected to the front member  70  at an inner end  78  of the frame and spaced from the front member at an outer end  80  of the frame. A first connecting member  82  extends along the outer end  80  for connecting between the front and rear members such that the frame  68  is triangular in shape. A second connecting member  84  extends parallel to the first connecting member from a midpoint of the front member  70  to a midpoint of the rear member  72 . A third connecting member  86  extends perpendicularly between the first and second connecting members to provide additional structural support to the frame. An additional connecting member  88  extends between the third connecting member and the rear member for supporting a lug  90  thereon. The lug  90  pivotally connects to a piston end  91  of the hydraulic cylinder  54 . In this arrangement, contraction of the hydraulic cylinder will pivot the frame  68  upwards with the pivot plate  62  and expansion of the hydraulic cylinder will pivot the frame  68  downwards with the pivot plate. 
     Three support members  92  extend perpendicularly from the rear member  72  of the frame for supporting an axle  94  on the support members spaced from and parallel to the rear member  72 . The support members are parallel to each other and equally spaced across the rear member. At a rearward end  96  of each support member, a bearing  98  is mounted within an aperture  100  for rotatably mounting the axle  94  therethrough. A plurality of upright discs  102  are axially aligned with the axle  94  and mounted equally spaced along the axle for rotation with the axle. Each disc  102  includes a concave inner surface  104  and a convex outer surface  106  such that each disc forms a scoop. 
     A column  108  extends upwards from each support member  92  at a position near the rear member. A header bar  110  connects across a top end  112  of the columns  108 . A plurality of scraper bars  114  extend rearwards and downwards from the header bar towards respective discs  102 . Each scraper bar  114  is a member of rectangular cross section adjacent to the inner surface of the disc at an end portion of the scraper bar. The scraper bars  114  remove excess mud and rocks from the discs in order that a cutting edge  116  along a periphery of the discs remains clear of obstruction. A support flange  118  extends rearwards from the header bar along a top side  120  of the scraper bars for providing additional support to the scraper bars. 
     In operation, the disc unit is mounted on an outer end  118  of the mouldboard  12  such that the disc unit extends over the shoulder  16  of the road  18  when the grader  14  drives down the road. The mouldboard mounted disc unit is arranged such that it may be viewed entirely from a cabin  122  of the grader such that an operator of the grader can supervise the use of the unit. 
     The discs  102  of the disc unit are arranged to extend forwards and laterally outwards with respect to the mouldboard and at an angle to a direction of the road such that the inner surface  104  faces forward and inward for cutting into the earth and scooping excess dirt and gravel inwards towards the road. A common axis of the discs extending through the axle  94  remains at a fixed angle to the mouldboard, however the mouldboard is adjustable through a variety of angles such that the angle of the discs in relation to the direction of the road is adjustable. 
     The horizontal angle of the discs is also adjustable. Repositioning the bolt  74  within the slotted aperture  76  at the inner end  66  of the pivot plate and pivoting the plate about the bolt  74  at the outer end  64  of the plate will adjust the height of the inner end of the frame and the discs mounted thereon in relation to the height of the shoulder and the road. In this manner the angle of the cutting edge  116  of the discs may be adjusted. Adjustment of the bolt  74  within the slotted aperture  76  at the inner end  66  of the pivot plate affects mainly the depth of cut of the discs nearest the inner end  78  of the frame for aligning the discs with the inclination of the road. 
     The hydraulic cylinder  54  connects at ports  124  and  126  to existing hydraulic lines extending from the grader for controlling contraction and expansion of the hydraulic cylinder using hydraulic controls on the grader. Expansion of the hydraulic cylinder will pivot the frame and discs downwards to engage the shoulder of the road in an engaged position. Contraction of the hydraulic cylinder will pivot the frame and discs upwards such that the discs are spaced from the road and the mouldboard mounted disc unit is in a raised position which will not affect normal operation of the grader. The hydraulic cylinder is adjustable to an unlimited number of depths of cut within a predetermined range of the cylinder. Adjustment of the hydraulic cylinder will primarily adjust the depth of cut of the discs. 
     The hydraulic system of the road grader is illustrated in FIG.  4 . The hydraulic system includes a pump  128  which provides pressurised fluid to a hydraulic control  130 . The hydraulic control  130  directs the pressurised fluid to either a first line  132  connected to the cylinder end  52  of the hydraulic cylinder  54  or a second line  134  connected to an opposing end of the cylinder. A pressure relief valve  136  interupts the first line  132  between a first portion  137  and a second portion  138 . The valve  136  provides pressure relief to the first line in response to a sudden blow to the disc unit resulting from an obstruction in the road. The pressure relief valve  136  includes a feedback line  139  connected to the second portion  138  and to an end of the valve. The feedback line activates the pressure relief valve  136  when the pressure is suddenly increased in the second portion  138  of the first line. When the valve is activated, the pressurised fluid in the first line  132  is released through a drain line  142  which connects to a reservoir  144 . The reservoir  144  is connected to the pump  128 . This arrangement will permit the disc unit to recoil upon impact with a rock or other solid object and prevent extensive damage to the unit. 
     While one embodiment of the present invention has been described in the foregoing, it is to be understood that other embodiments are possible within the scope of the invention. The invention is to be considered limited solely by the scope of the appended claims.