Abstract:
A edge for attaching to a moldboard, having a rearwardly protruding trailing wear plate is disclosed. This device can be manufactured as one piece incorporating the standard edge and additional trailing wear plate or can be in the form of a bolt-on trailing wear plate that would become a component of a standard moldboard edge. The edge is applicable to motor graders, snowploughs or any other machine or attachment that performs similar functions. The trailing wear plate prolongs edge life, reduces grader bounce, enhances grader stability, reduces operator fatigue, allows greater moldboard control, enables greater grading speed and when these factors are combined offer substantial increased efficiency.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation of International PCT Application No. PCT/CA2005/001256 filed on Aug. 12, 2005 which claims priority from Australian Provisional Application No. 2004904521, filed on Aug. 12, 2004, the contents of which are both hereby incorporated by reference. 
     
    
     TECHNICAL FIELD  
       [0002]     The present invention relates generally to moldboards or moldboard assemblies, and in particular, to a edge therefor.  
       BACKGROUND OF THE INVENTION  
       [0003]     Various utility vehicles or machines are used in the construction and maintenance industries. Of these machines, certain ones are used for moving materials, such as earth, gravel, asphalt, snow, etc. To move these materials, the utility or construction machines typically have a blade, which can push or scrape the material across a working ground surface, pile of material etc. These blades and associated structures are commonly referred to in the industry as moldboards or moldboard assemblies. These machines may include, but are not limited to bulldozers, snowploughs, scrapers, trucks, and motor graders. The following will describe the use of a moldboard with a motor grader. However, it will be appreciated that the same is applicable to other machines that use a moldboard, moldboard assembly, or similar device for moving material.  
         [0004]     Motor graders are used to grade a base material such as soil, gravel or sand to provide a generally planar or contoured surface, or a consistent grade to a surface, such as a road bed or road shoulder. The grading may be applied to surfaces directly under the machine as well as down and up slopes, and on either side of the machine. Generally, a motor grader includes a tractor unit (or other suitable construction vehicle) with a moldboard assembly coupled to the front, a side, or below the unit. The tractor unit is typically carried on large rubber tires, and usually has a hydraulic control system for controlling the movements of the moldboard or moldboard assembly and the unit itself. An operator can typically control the moldboard&#39;s elevation, tilt, and yaw to orient the lower edge of the moldboard in a desired manner, depending on the nature of the application. Typically, the moldboard assembly includes a moldboard as well as an adjustable mounting assembly for coupling the moldboard to the tractor unit. As the tractor unit moves, the moldboard assembly travels over the ground, so that the lower edge of the moldboard engages the ground for moving material, such as soil, gravel, etc., so as to displace, distribute or level the material. Most moldboard assemblies have two horizontal slide rails secured on longitudinal channel type members, which are typically secured to the rear of the moldboard. These channel members are horizontal, serve to reinforce the moldboard, and typically support the slide rails.  
         [0005]     The displacement, etc. of material is accomplished by the accurate positioning and control of the moldboard assembly and moldboard. The moldboard or moldboard assembly is movable relative to a drawbar used to secure the moldboard assembly to the grader frame. The securement of the moldboard or moldboard assembly beneath the grader frame should be designed to avoid wobble or excess clearance in the support arrangement, as poor tolerance variations can significantly affect the operator&#39;s control of the moldboard, and the precision that is possible in a grading operation.  
         [0006]     Moldboards may also be provided with replaceable edges, typically referred to as cutting or wear edges. The edge can be made of steel with various hardening treatments applied thereto, and may have extra hard alloy inserts installed. The edge is a wearable element that can be replaced more easily and at a lower cost than replacing the entire moldboard. The edges vary considerably in material, heat treatment, thickness and width. These variations are dependent on the particular machine on which the edges are to be installed (e.g. motor grader, bulldozer etc.), the operating conditions of the machine, and the operator or owner&#39;s preferences. Many edge designs include a curved cross section so as to match the curve of the moldboard. Other edges are flat in cross section, and some edges consist of replaceable freely rotating bits mounted in a flat or curved steel plate.  
         [0007]     U.S. Pat. Nos. 6,813,849 and 5,076,370, the contents of which are incorporated by reference, provide examples of the above.  
         [0008]     A typical motor grader provides a very stable configuration in order to maximize the stability and accuracy of the moldboard when in use. Because of this inherent stability, a motor grader can smooth or work a surface at a relatively high speed compared to most other pieces of construction equipment, particularly in light and medium load conditions. A light to medium load condition exists when a relatively small amount of material is being moved by the moldboard, such as during a smoothing or finishing operation, compared to a heavy load condition, wherein a relatively large amount of material is being moved, such as during a scraping or levelling operation. There is, however, an upper speed limit at which the motor grader can effectively operate due to a combination of mechanical effects, which are common to the typical motor grader configuration, and operator factors such as concentration, fatigue, reaction time, etc.  
         [0009]     While it can provide stable moldboard positioning, the typical motor grader configuration may exhibit vertical up and down movement (e.g. “bounce”) especially under light to medium load conditions. Motor grader “bounce” can also be aggravated as the travel speed of the motor grader increases. If the travel speed of the motor grader is increased beyond a suitable level, the motor grader will begin to exhibit up and down movement (e.g. begin to bounce). The suitable level or threshold before bounce is experienced varies depending on several conditions, such as, for example, the surface conditions, machine size and load requirements. The bouncing can be aggravated, or may even be initiated, by the edge of the moldboard digging into the road or work surface and causing the moldboard or moldboard assembly, and in turn the motor grader to be displaced vertically downward. This will then produce a reactive force due to the elastic deformation of the motor grader frame and the tires, which may then cause the motor grader to bounce upwards. Since the motor grader moldboard creates a depression in the working surface, which the rear tires will eventually traverse, an additional “bouncing” force can be applied to the motor grader through the rear wheels. Normally this scenario occurs when the motor grader is moving, and thus the motor grader may rapidly begin to “bounce” in a harmonic fashion such that all the forces acting upon the motor grader cause the bouncing to worsen.  
         [0010]     Motor grader bounce may cause imperfections or divots, also known as rippling or washboarding, in the road or work surface being graded, which leaves an unacceptable finish. As a result, these imperfections require, in most instances, at least one additional pass to correct. Since a motor grader&#39;s primary purpose is to produce a smooth surface, such imperfections are undesirable and are to be avoided. A motor grader is typically operated at a speed at which the “bounce” threshold for any particular grader is not crossed. This “bounce” threshold varies based on vehicle weight, specific configuration, weight distribution, tire size and pressure, road or working surface condition, moldboard length and position etc. In general, such a threshold will not be crossed if the motor grader is driven less than, for example, 6-11 kph, depending on the size of grader and the load conditions. Motor grader manufacturers usually suggest keeping travel speed as high as possible for maximum productivity, but low enough to prevent motor grader bounce.  
         [0011]     In addition to keeping the speed of the motor grader below the “bounce” threshold, operators can also tilt the moldboard to carry more material on the moldboard, wherein the gravel, dirt, etc., will provide a dampening effect, allowing an increase in grading speed. Doing so, however, greatly decreases the cutting ability of the moldboard, and the large quantity of material in front of the moldboard requires considerably more power to carry the load. The overall effect allows a slightly increased grading speed, with a considerable increase in power requirements. The downsides of this arrangement include: 1) an increase in fuel consumption by the motor grader; and 2) an accelerated wear of the motor grader drive train and tires.  
         [0012]     Grader bounce is inherent in all graders and is a factor inhibiting grader productivity. All grader operators experience this problem and are continuously forced to operate at speeds that are slower than ones which they desire to experience while controlling the grader. These pitfalls are also experienced with other construction machines, such as bulldozers, scrapers and ploughs. Other factors affecting performance include that prior art edges do not allow precise moldboard control, are subject to uncontrolled movements, such as grader bounce, and are generally subject to uneven wear and a short life. They also contribute to an uneven or inconsistent graded surfaces, and can damage road surfaces covered with snow or debris.  
         [0013]     It is therefore an object of the present invention to provide a moldboard edge that obviates or mitigates the above-mentioned disadvantages.  
       SUMMARY OF INVENTION  
       [0014]     To combat the above, a moldboard edge has been developed that addresses the deficiencies noted herein. This edge can be constructed in a number of different configurations and provide the same effect to the motor grader.  
         [0015]     In one aspect, the present invention provides a edge for attaching to the bottom edge of a moldboard. The edge has a leading member that has a working surface for moving material, the leading member having an upper end adapted for attachment to the moldboard to orient the working surface towards the forward direction of travel of the moldboard. The edge also has a trailing member protruding rearwardly from a lower end of the leading member and providing a ground engaging surface.  
         [0016]     In another aspect, the present invention provides a trailing member for attaching to a moldboard, wherein the moldboard has a replaceable edge attached to a bottom edge thereof. The trailing member has an attachment member for attaching the trailing member to the rear of the moldboard, the attachment member having an attachment end and a lower end. The trailing member also has a ground engaging member attached to the lower end of the attachment member and oriented such that upon attaching the attachment member to the moldboard at the attachment end, a leading end of the ground engaging member is positioned adjacent to the rear of a lower end of the replaceable edge. The ground engaging member provides a ground engaging surface.  
         [0017]     In yet another aspect, the present invention provides a moldboard having a concave working surface for moving material, a lower end that has a edge for scraping material from a surface, and a trailing member. The trailing member protrudes rearwardly from the lower end and provides a ground engaging surface.  
         [0018]     In yet another aspect, the lower end of the above moldboard is offset rearwardly from the working surface to permit the attachment of a replaceable edge thereto. As a preference, the trailing member has a trailing wear plate attached to its underside, and the lower end has a length less than that of the replaceable edge, such that a downward facing surface of the replaceable edge is contiguous with a ground engaging surface of the trailing wear plate.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]     Various objects, features and attendant advantages of the present invention will become more fully appreciated and better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views.  
         [0020]      FIG. 1  is a pictorial perspective view of a motor grader having a prior art moldboard assembly attached thereto.  
         [0021]      FIG. 2  is a side view of the prior art moldboard assembly of  FIG. 1 .  
         [0022]      FIG. 3  is a side view of an embodiment of the present invention.  
         [0023]      FIG. 4  is a side view of the embodiment of  FIG. 3  in an alternative configuration.  
         [0024]      FIG. 5  is a side view of another embodiment of the present invention.  
         [0025]      FIG. 6  is a side view of another embodiment of the present invention.  
         [0026]      FIG. 7  is a side view of another embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0027]     In order that the present invention may be more fully understood, it will now be described, by way of example, with reference to the accompanying drawings in which  FIGS. 3 through 7  illustrate embodiments of the present invention.  
         [0028]     A typical motor grader  10  is shown pictorially in  FIG. 1 . The motor grader  10  is used herein, by way of example only, to illustrate a typical application of the present invention. The motor grader  10  is used to move material over a surface  12 . The motor grader  10  is generally comprised of a tractor unit  14  and a moldboard assembly  20 . The moldboard assembly  20  is attached to the tractor unit  14  such that a concave working surface faces the direction of travel of the motor grader  10 . The moldboard assembly  20  may be operated by a hydraulic control unit (not shown) to vary its elevation (distance raised from the ground), tilt (angular position displacement about a horizontal axis), and yaw (angular displacement about a vertical axis), as desired.  
         [0029]     A side view of a prior art moldboard assembly  20  is shown in  FIG. 2 . The moldboard assembly  20  has a moldboard  22  having a generally concave working surface  23 . The lower end of the moldboard  22  terminates at an offset rail  24 . The rail  24  has a portion that extends rearwardly a distance that is substantially similar to the thickness of a replaceable edge  26  and a portion that extends downwardly, generally along the direction of the concave working surface  23  of the moldboard  22 . It will be understood that the rail  24  may be flat (as shown in  FIG. 2 ) or may follow the curvature of the moldboard  22  (not shown). The rail  24  supports the edge  26 , which is attached thereto using a series of retaining bolts  29  fed through a complementary series of holes  28 . The holes  28  and bolts  29  are spaced along the rail  24  and edge  26  at any suitable interval. It will be appreciated that the cutting edge  26  may be attached to the moldboard  22  using any suitable means, and bolts  29  and holes  28  are shown for exemplary purposes only.  
         [0030]     The moldboard assembly  20  has an upper slide rail  30  supported by a cross member  32  and a lower slide rail  34 . The slide rails  30  and  34  are used for attaching the assembly  20  to the tractor unit  14  and for adjusting the position of the moldboard  22 . It will be understood, however, that any configuration of slide rails can be used in the attachment of assembly  20  to unit  14 . It will also be understood that other moldboard assembly means, known to a person skilled in the relevant art, could be used with the present invention. Examples of such attachment means, are provided in U.S. Pat. Nos. 6,904,978; 6,813,849; and 6,799,640; the contents of which are incorporated herein by reference.  
         [0031]     Typically, the moldboard  22  may be ⅞ inch thick, 22 inches wide, and 12 feet long. It will be appreciated, however, that the moldboard  22  will be sized and configured according to its particular application. As such, many possible sizes and configurations for the assembly  20  and particularly the moldboard  22  can be used.  
         [0032]     An improved edge  40  in accordance with the present invention is shown in  FIG. 3 . The edge  40  is adapted to be attached to the moldboard  22  using the bolts  29  and holes  28 , in place of the edge  26 . Therefore, the edge  40 , in this example, would also have a series of corresponding holes  28  that match those in the rail  24 .  
         [0033]     The edge  40  has a leading member  42  that has a working surface  43  that is generally contiguous with the working surface of the moldboard  22  and terminating at a tip  47 . While the member  42  is preferably shaped to conform with the curvature of the moldboard  22 , it will be appreciated that the member  42  may also comprise any suitable contour. Working surface  43  of the member  42  is used to scrape and move material over the surface  12 . The leading member  42  is capable of performing these tasks in a manner similar to the edge  26  as noted above.  
         [0034]     Edge  40  also has a trailing member  44 . The trailing member  44  protrudes or extends rearwardly from the leading member  42 . Since the trailing member  44  extends from the leading member  42 , a ground engaging surface  45  is provided, extending rearwardly from tip  47 . The trailing member  44  is preferably a steel plate and preferably protrudes or extends rearwardly from the leading member  42  such that a rearwardly facing angle  46  is formed between the working surface  43  and ground engaging surface  45 , each of which terminate at the tip  47 . Preferably, this angle varies between approximately 75 and approximately 105 degrees.  
         [0035]     The angle  46  of the member  44  with respect to the member  42  depends on the orientation of the moldboard assembly  20 . For example, a generally vertical orientation of the moldboard  22  is shown in  FIG. 3 . The angle of the working surface  43  of the leading member  42  with respect to the ground engaging surface  45  of the trailing member  44 , is determined by positioning the top of the moldboard  22  in this vertical position. In this position, the ground engaging surface  45  of the trailing member  44  is angled with respect to the working surface  43  of the leading member  42  in such a way to enable the ground engaging surface  45  of the trailing member  44  to maintain contact with the ground surface  12  along a portion of the length of the ground engaging surface  45 , preferably a substantial portion thereof.  
         [0036]     It will be understood that this angle may vary depending on the use of the grading machinery. The dimensions of the invention will vary and shall not be limited to having the face of the leading member  42  constructed with dimensions similar to the standard edge  26 , and with a similar thickness.  
         [0037]     However, it will be appreciated that since the moldboard assembly  20  can be oriented in a number of configurations, the ground engaging surface  45  of the trailing member  44  will not always maintain contact with the ground surface  12  along a substantial portion thereof. Such a configuration is shown in  FIG. 4 . The configuration in  FIG. 4  is desirable for digging into the surface  12 , which will be explained in greater detail below.  
         [0038]     It will be understood that the trailing member  44  may be any length as desired based on the application of the moldboard. The choice of length of the trailing member  44  may vary depending on the particular application, surface conditions, etc.  
         [0039]     Trailing member  44  helps to reduce grader bounce. With the embodiment shown in  FIG. 3 , grader bounce can be greatly reduced or even eliminated, and material can be moved at speeds up to 25 kph, depending on load conditions, etc. The increased stability of the moldboard assembly  20  as a result of trailing member  44  is greatly improved, and the concentration required while operating the grader  10  can be reduced.  
         [0040]     The trailing member  44  shown in  FIG. 3 , can be constructed of known materials for use in constructions of edges, such as, for example, cutting or wear edges. The thickness of the trailing member  44  will vary depending on the application. Its thickness would preferably be between approximately 15 mm and approximately 60 mm. An edge is preferably approximately 16 mm thick with an effective working thickness (i.e. a minimum thickness permitting operability) of approximately 10 mm. The trailing member  44  would start to bend, however, when worn to a thickness of approximately 5 mm. A thickness of greater than approximately 50 mm could be anticipated or used in heavy applications.  
         [0041]     The length of the ground engaging surface provided by the edge  40  will also vary depending on application. For example, for general road maintenance, a length of approximately 150 mm would be appropriate, and preferably, the length of the ground engaging surface is in the range of approximately 50 mm to approximately 200 mm.  
         [0042]     Referring to  FIG. 4 , hard material can be cut by tilting the moldboard  22  forward relative to the generally vertical position shown in  FIG. 3 , allowing the tip  47 ′ of the leading member  42 ′ to easily penetrate harder material. Loose and soft material can be graded using the moldboard  22  in the generally vertical position (i.e. that shown in  FIG. 3 ) to eliminate bounce. When cutting, grader bounce is usually not a problem as the machine is usually under a greater load and operating at a slower speed. Typically, grading applications result in a ratio of approximately 25% of operating time designated to cutting material (such as shown in  FIG. 4 ) and approximately 75% of operating time designated to light to medium grading of loose or soft material (such as shown in  FIG. 3 ). It will be understood that such ratios will vary depending on the nature of the application. With this typical ratio, it will be understood that with the presence of trailing member  44 , the tip  47  of the leading member  42  will more easily self sharpen during grading operation and as such will be able to penetrate harder material more easily than a conventional edge  26 , which is not self sharpened.  
         [0043]     Most construction applications involve grading loose or soft materials. Therefore, the moldboard  22  is most typically positioned in the generally vertical position shown in  FIG. 3 . Maintenance grading, especially dry grading corrugations, involves grading loose material, in which case the moldboard  22  would also be positioned in this position. Dry grading with the edge  40  at increased speeds has the added benefit of throwing loose material from the moldboard  22  at a distance equivalent to a longer moldboard travelling at a slower speed.  
         [0044]     Another embodiment of the present invention is shown in  FIG. 5 . In this embodiment, the assembly  120  has a modified moldboard  122 . Elements similar to those shown in  FIG. 3  are given like numerals with the prefix “I”. In this embodiment, a modified edge  140  is provided, wherein a trailing foot  52  extends rearwardly from the lower end of the rail  124 . A standard replaceable cutting edge  26  can be affixed to the rail  124  using similar bolts  29  and holes  28  as before. The vertical length of the downward portion of rail  124  may be less than the length of the edge  26 , such that when the cutting end of the edge  26  rests on the surface  12 , the lower edge of foot  52  is offset from the tip  147  of edge  26 , and does not engage with the surface  12 .  
         [0045]     A replaceable, wearable trailing member  144  can thus be affixed under the foot  52  to provide a ground engaging surface  145  that is substantially contiguous with the ground engaging surface  126  of the edge  26 . The trailing member  144  is affixed to the foot  52  using a set of bolts  51  and holes  50 . The bolts  51  and holes  50  are suitably spaced along the foot  52  similar to the bolts  29  and holes  28 , as desired.  
         [0046]     In the embodiment shown in  FIG. 5 , the modified moldboard  122  enables replaceable members (i.e.  26  and  144 ) to be discarded and replaced as needed during operation of the motor grader  10 . This prolongs the life of the moldboard  122  whilst providing the benefits of having a trailing member  144 , i.e. to inhibit motor grader bounce.  
         [0047]     A further configuration is shown in  FIG. 6 , where an attachment member is attached to the back of the moldboard  222 , in this case, a bar  58 . Elements similar to those shown in  FIG. 3  are given like numerals with the prefix “ 2 ”. At the lower end of the bar  58  is a modified trailing member  244 . As shown in  FIG. 6 , the trailing member  244  is arranged in such a manner to have a ground engaging surface  245  that would be in flat contact with the working surface  12  when the moldboard assembly  220  is in it&#39;s working position (i.e. as shown in  FIG. 6 ). A standard edge  26  could be bolted to the front of the moldboard  222 . The edge  26  and the bar  58  would be affixed to the moldboard  222  using a similar series of bolts  29  and holes  28 . The resulting combination would provide both the normal front wear surface of the edge  26 , and the horizontal trailing edge  244  which inhibits motor grader bounce.  
         [0048]     A further configuration is shown in  FIG. 7 , implemented on a snow wing. Elements similar to those shown in  FIG. 3  are given like numerals with the prefix “ 3 ”.  
         [0049]     A snow wing is an attachment for a motor grader that extends to one side of the machine, and is designed to displace the material being moved far back from the road surface to eliminate snow build-up and facilitate continued snow displacement. A snow wing is described in U.S. Pat. No. 5,177,887, the contents of which are incorporated herein by reference.  
         [0050]     In this embodiment, a series of snow wing shoes  60  would be bolted to the rear of the moldboard  322  in a manner similar to before, using a series of bolts  29  and holes  28 . Snow wing shoes  60 , typically equipped with steel or cast iron, are provided on the back of the wing edge to prevent the wing from digging into a soft surface or from contacting a hard wearing surface such as a road, which may cause damage to the road surface. A continuous series of these shoes  60  located across the back of the moldboard  22 , would again provide the surface area necessary to inhibit motor grader bounce. The shoes  60  can be spaced as necessary, depending on the configuration of the motor grader  10 , the operating conditions, and operator or owner preference etc. A continuous row may be placed with no gaps between the shoes  60  or a row with gaps of varying width may be installed as desired.  
         [0051]     Therefore, it has been shown that a number of different configurations of trailing members may be used with a motor grader  10  to prevent bounce, and improve machine productivity. These include both one piece (e.g.  40 ) or multiple piece edge assemblies (e.g.  140  or  240 ); used with standard replaceable edges  26  or providing an integral cutting edge (e.g.  42 ); or using a series of shoes  60 .  
         [0052]     It will be appreciated that the present invention may also be used to increase the performance of other machines, such as but not limited to, bulldozers and scrapers.  
         [0053]     The operation of the present invention will be discussed generally in reference to  FIG. 3 . In light to medium load operating conditions, the downwardly facing ground engaging surface  45  of the generally horizontal trailing member  44  of edge  40  shown in  FIG. 3 , would preferably be in full contact with the road or working surface. For clarity, the following description, which is applicable to all possible embodiments of the present invention, will make reference primarily to the embodiment shown in  FIG. 3 . However, it will be understood that the other embodiments noted above, may also be used as noted below.  
         [0054]     While the generally horizontal trailing member  44  of edge  40  can be generally parallel with the work surface, it will be understood that depending on the angle at which the moldboard  22  is positioned relative to the work surface  12 , or the configuration of the trailing member  44 , the trailing member  44  can be angled relative to the working surface  12  so that at least a portion of trailing member  44  is in contact with the working surface  12 , such as the configuration shown in  FIG. 4 . Such an angle may be used when the leading edge of the leading member  42  is used to dig into the surface  12 . Typically, the moldboard  22  would be in a generally vertical position. In other words, a line connecting the upper end of the moldboard  22  with the lower end of the leading member  42  will be generally perpendicular to the working surface  12 , as shown in  FIG. 3 .  
         [0055]     It will be understood, however, that the moldboard  22  may be used in a position wherein the assembly  20  may be angled relative to the direction of travel of the motor grader  10 , i.e., rotated about a vertical axis.  
         [0056]     During operation, the trailing member  44  acts as a stabilizer of the moldboard assembly  20  to reduce grader bounce. When the grader  10  is grading a surface  12  at a speed that would normally cause the motor grader  10  to bounce (e.g. typically greater than 6-11 kph depending on the size of the machine etc.), at least a portion of ground engaging surface  45  of the trailing member  44  is in contact with the working surface  12  such that a sufficient amount of the surface area of the trailing member  44  prevents the tip  47  of the leading member  42  from digging into the working surface.  
         [0057]     When the tip  47  cannot dig into the working surface  12 , the normal bouncing sequence cannot commence. Since bouncing cannot be initiated, the speed at which the motor grader  10  can operate can be increased. The speed of the grader can be increased up to 2 to 3 times the speed normally associated with grading. In most cases the speed can be increased up to the limit of the power available to the motor grader drivetrain.  
         [0058]     As noted above, the moldboard  22  is in a substantially vertical position, which typically allows the gravel or dirt carried in front of the moldboard  22  to roll and tumble freely, thus increasing the efficiency of the movement of material, and contributing to improved overall machine efficiency.  
         [0059]     As noted previously, the increased speed at which the machine  10  can grade material will dramatically improve the productivity of the motor grader  10 , and improve the condition of the surface  12  being graded, by substantially eliminating the washboarding effect caused by motor grader bounce.  
         [0060]     In addition, the use of a trailing member  44  can be used on construction machines of different configurations than motor graders  10 . Any machine that utilizes a ground engaging surface or edge can become unstable at a given speed or condition and would benefit from the use of such a trailing member  44 . Machines such as bulldozers and scrapers would fit into this category.  
         [0061]     A further benefit is that the edge has substantially more material in contact with the working surface, thus reducing the rate of edge wear. Since standard grader moldboard edges  26  may wear out in as little as 2 days in many conditions, the increased quantity of material in the improved edges (e.g.  40 ,  140 ,  240 ,  340 ,  60 , and  72 ) will result in a situation where, for a given condition or operating mode that will yield a consistent material wear rate, the edges may now last for up to six times longer. In the example above, the edges will typically last up to twelve days instead of two.  
         [0062]     As noted above with respect to  FIG. 4 , the motor grader  10  is sometimes used to cut down into the working surface  12 , such as in road construction or heavy material removal and may be referred to as a “cutting mode”. The motor grader  10  in such cases generally operate at low speeds due to the heavy load of material on the working surface of the moldboard  22  where motor grader bounce is not a concern. In these situations, the improved edge (e.g.  40 ′) allows the moldboard  22  to be tilted forward slightly, where the trailing member  44 ′ is lifted off the working surface  12 , as shown in  FIG. 4 . The angle between the trailing member  44 ′ and the surface  12  is dependent how deep the operator of the motor grader  10  wishes to dig.  
         [0063]     The sharp point  47 ′ of the leading member  42 ′ is then in contact with the working surface  12 , and due to the dramatically reduced contact area, the edge will cut into the surface  12  much more readily, and behave in a manner similar to a standard moldboard edge  26  as shown in  FIG. 2 .  
         [0064]     The operator has the flexibility to operate the motor grader  10  in both surface grading and cutting modes with the same edges (e.g.  40 ) installed and needs only adjust the tilt of the moldboard  22  which is commonly done by operators anyway.  
         [0065]     Aspects of this invention have been shown, in various testing, to increase the productivity of the motor grader  10  in excess of 100% through enabling an increased grading speed. It appears that carbide inserts may be an option in preserving the cutting edge tip, especially when working hard abrasive materials for extended periods. Hardfacing (i.e. the application of materials having superior hardness to a substrate) and or carbide inserts may also allow the trailing member  44  to be constructed of thinner, lighter material, enabling easier attachment and removal.  
         [0066]     The present invention may also reduce the likelihood of having the tip  47  cut into the underlying surface, when used with a snow plow. This enables the snow plow to be operated at greater speeds due to the reduction in grader bounce. It could be used with all types of snow plowing equipment.  
         [0067]     By adding a trailing member (e.g.  44 ) to the bottom of the standard edge the surface area of the edge contacting the ground is greatly increased making depth and applied pressure control more accurate. The downward pressure on the increased surface area provided by the trailing member of the present invention results in less wear and increased edge life due to the pressure being spread out over a wider surface area than prior art edges.  
         [0068]     The profiles of the present invention have widths that are specified by manufacturers, and typically each moldboard  22  would have two or more widths bolted to them similar to current standard edges  26 . To enable penetration in hard surfaces, the moldboard  22  is simply tilted forward to allow the cutting edge tip to easily penetrate the surface as in  FIG. 4  until the required depth of cut is appropriate. The moldboard  22  is then rolled back to the position shown in  FIG. 3 .  
         [0069]     This invention would ideally be manufactured as a long rolled and profiled length at a steel mill, and then cut and drilled to the particular manufacturer&#39;s specifications. Alternatively, welding the trailing member  44  to edges  26  is an option and, used edges  26  may also be recycled as a wear plate  44 .  
         [0070]     Different applications may warrant different specifications depending on materials being graded e.g. salt, snow, gravel sand or any other material.  
         [0071]     Hardfacing, carbide inserts or other counter wear treatments, such as those noted above, can be performed on the trailing members, leading members or standard edges  26  to increase durability, depending on the application.  
         [0072]     Although the present invention has been described according to certain specific embodiments, it will be appreciated that various modifications thereof will be apparent to a person skilled in the art without departing from the scope of the invention as outlined in the claims appended hereto.