The present disclosure relates to a moldboard and, more particularly, to a single-piece moldboard having dually-rotated wing sections.
Excavation machines, for example dozers and motorgraders, are commonly used in earth moving applications. These machines typically have a frame supported by one or more traction devices, and a work tool known as a moldboard movably connected to the frame. Hydraulic actuators are generally disposed between the frame and the moldboard to move, lift, rotate, and/or tilt the moldboard during operation.
Typical universal blade (U-blade) or semi-universal moldboards include a main section and opposing side or wing sections. Each section is fabricated separately from an elongated flat panel. This fabrication can include cutting of the general shape of each section from the flat panel, rolling of the cut shapes in a length direction to form matching curvatures, and welding together of the separate pieces along their matching seams. Depending on the intended machine and material application, each moldboard may have sections with different shapes, sizes, and/or radii of curvature. Accordingly, design and fabrication of a typical moldboard can be complex and labor intensive.
One attempt to improve fabrication of a moldboard is disclosed in U.S. Patent Application Publication 2008/0314607 of May that published on Dec. 25, 2008 (“the '607 publication”). Specifically, the '607 publication discloses a process for fabricating a U-blade dozer moldboard from a flat, one-piece material blank. The fabrication process involves flame-cutting two inverted V-shaped notches within a lower edge of the blank, the notches defining outer wing sections at opposing sides of a central body section. The tops of the notches define brake lines. A rolling operation is then performed to create a uniform curvature in a lower portion of the moldboard, below the brake line. Each of the wing sections are then bent approximately 30° inward towards each other. This bending step brings the opposing edges of each notch into engagement with each other. Each bend is performed in a vertical direction across a flat upper portion, about a line extending upward from the notches. Fabrication of the moldboard is finalized by welding the closed joints remaining between the moldboard wings and the center section.
While the moldboard of the '607 publication may have reduced complexity and fabrication requirements, it may still be less than optimal. Specifically, the wing sections of the moldboard described in the '607 publication are only bent (rotated) in one direction. This geometry may have limited precision, and the process of the '607 publication cannot be applied to moldboards having more complex geometry. Further, the '607 publication does not disclose how to determine geometry of the notches required to ensure that, after the bending step is complete, edges of the notches align correctly.
The present disclosure is directed to overcoming one or more of the problems set forth above and/or other problems of the prior art.
In one aspect, the present disclosure is directed to a moldboard. The moldboard may include a center section that is curved about a center axis, a first wing section connected to a first side of the center section, and a second wing section connected to a second side of the center section. The first wing section may be curved about a first wing axis, and the second wing section may be curved about a second wing axis. The first and second wing axis may be rotated in at least two directions relative to the center axis.
In another aspect, the present disclosure is directed to a method of designing a moldboard. The method may include receiving a desired radius of curvature of a center section, a first wing section, and a second wing section. The method may also include receiving a desired first rotation angle of a first wing section axis and a second wing section axis relative to a center section axis, and receiving a desired second rotation angle of the first and second wing section axes relative to the center section axis. The method may further include determining a resultant wing angle as a function of the first and second rotation angles, and determining a plurality of angles associated with intersections of the center axis, the first wing section axis, and the second wing section axis. The method may additionally include generating notch curvatures separating the center section from the first and second wing sections based on the plurality of angles.
In yet another aspect, the present disclosure is directed to a method of fabricating a moldboard. The method may include cutting a flat metal panel along notch curvatures dividing a center section from first and second wing sections. The notch curvatures may be defined at least partially by a sinusoidal curve calculated based on cylinder unwrapping equations for curvature intersection of the center section and the first and second wing sections. The method may also include rolling the center section, the first wing section, and the second wing section to form curvature in the center section and the first and second wing sections after the flat metal panel has been cut. The method may further include bending the flat metal panel along fold lines between the center section, the first wing section, and the second wing section to bring cut edges of the center section, first wing section, and second wing section together. Curvature axes of the first and second wing sections may be rotated in at least two directions relative to a curvature axis of the center section during bending of the flat metal panel. The method may further include welding the cut edges together.
In the disclosed embodiment, three different actuators 18 are used to move moldboard 20. Specifically, a center actuator 18C is shown in
Moldboard 20 may be an assembly of components that together forms a blade, such as a generally U-shaped blade used to move ore or overburden. For example, moldboard 20 may include a body 28, and a cutting edge 30 removably connected to body 28. Cutting edge 30 may be formed by a plurality of wear members 32 that are replaceably connected to ground engaging edges 33 (shown in
As shown in
Center section 36 may be a shaped panel having ground engaging edge 33 at one side, a flat upper portion 42 located opposite ground engaging edge 33, and a lower portion 43 located between ground engaging edge 33 and upper portion 42. Lower portion 43 may be curved along it height (i.e., in the direction between ground engaging edge 33 and upper portion 42 that is substantially orthogonal to the push direction of moldboard 20) about a center axis 44. Center axis 44 may be generally aligned with horizontal axis 24 (referring to
First and second wing sections 38, 40 may be substantially identical mirror images of each other, and similar to center section 36. Specifically, each of first and second wing sections 38, 40 may be a shaped panel having ground engaging edge 33 at one side, upper portion 42 located opposite ground engaging edge 33, and lower portion 43 located between ground engaging edge 33 and upper portion 42. In the disclosed embodiment, lower portions 43 of first and second wing sections 38, 40 may have the same curvature as lower portion 43 of center section 36 and a tangent to the curvature of lower portions 43 of first and second wing sections 38, 40 may similarly form the interior angle α. It is contemplated, however, that the curvature of first and/or second wing sections 38, 40 may be different from the curvature of center section 36, if desired, and/or that the curvature of any one or more of these sections may form a different interior angle, if desired.
Although similar in contour, first and second wing sections 38, 40 may be connected to center section 36 in an advantageous orientation. Specifically, lower portion 43 of first wing section 38 may be curved about a first wing axis 46, while lower portion 43 of second wing portion 40 may be curved about a second wing axis 48. And first and second wing axes 46, 48 may not be aligned with center axis 44. For the purposes of illustrating the orientation of first and second wing axes 46, 48 relative to center axis 44, each of center, first wing, and second wing sections 36, 38, 40 are displayed generically as intersecting cylindrical surfaces in
As can be seen in the top view of moldboard 20 in
As can be seen in the front view of moldboard 20 in
The rotations of first and second wing sections 38, 40 relative to center section 36 may create some unique relationships that provide advantages to moldboard 20. For example, a blade rotation ratio of first and second wing sections 38, 40 in the first direction may be about 0.005-0.02 (i.e., a ratio of angle θ to curvature radius=10°−40°/2000 mm). Similarly, a blade rotation ratio of first and second wing sections 38, 40 in the second direction may be about 0-0.015 (i.e., a ratio of angle ω to curvature radius=0°−30°/2000 mm). In another example, a multi-direction rotation ratio of first and second wing portions 38, 40 may be about 0 to 3 (i.e., a ratio of angle ω to angle θ=0 θ/40° to 30°/10°. These unique parametric relationships may help to improve material flow across moldboard 20.
The rotations of first and second wing sections 38, 40 about horizontal axis 52 may have several different effects on the way that machine 10 engages ground surface 22 (referring to
The different lengths of ground engaging edges 33 at first and second wing sections 38, 40 relative to the length of ground engaging surface 33 at center section 36 may also create some unique relationships that provide advantages to moldboard 20. For example, a ratio of the length of ground engaging surface 33 at first wing section 38 (and/or second wing surface 40) relative to the length of ground engaging surface 33 at center section 36 (i.e., a base ratio) may be about 0.1-0.5. Similarly, a ratio of the length of ground engaging surface 33 at first wing section 38 (and/or second wing surface 40) relative to the height of center section 36 (i.e., a base to height ratio) may be about 0.1-0.5. These unique parametric relationships may help to improve a cutting ability of moldboard 20.
In addition, the movement of material may generally follow the intersections of first and second wing sections 38, 40 with center section 36. And as shown in
Regardless of the rotation directions of first and second wing sections 38, 40, ground engaging edges 33 of all sections 36-40 may be configured to engage ground surface 22 (referring to
In the exemplary embodiment shown in
Design of moldboard 20 (e.g., generation of the curvatures of notches 56 and/or the locations and orientations of fold lines 58) is, in itself, a unique process. Description of this process will be provided in more detail in the following section to further illustrate the disclosed concepts.
The disclosed moldboard may be applicable to any machine where improved function, durability, and cost are desired. The disclosed moldboard may have improved function through the use of unique geometric configurations achieved through parametric curve relationships that enable the blade cutting force and material flow to be tailored to specific worksite conditions and/or intended applications. The disclosed moldboard may have improved durability due to its fabrication from a single-piece blank of metal. The disclosed moldboard may have improved cost through a unique design process, which will be described in more detail below, that reduces an overall design time and streamlines the fabrication process.
Design of a new moldboard 20 may begin with receipt of desired moldboard dimensions. These desired moldboard dimensions may include, for example, a desired radius of curvature r of center section 36, which should correspond to the radius of curvature of first wing section 38 and second wing section 40. The desired moldboard dimensions may also include a desired value for first rotation angle θ and a desired value for second rotation angle ω. These values may be determined by a potential owner and/or worksite manager of machine 10, and correspond with an intended application of machine 10. For example, in applications where the material to be moved by machine 10 is generally loose (e.g., wood chips or piled coal), ground penetration may not be the most important factor. In these applications, a smaller positive angle ω (and/or a greater negative angle ω) may be desired. In contrast, in applications where greater ground penetration is desired (e.g., in applications involving hard-packed overburden), a larger positive angle ω may be desired.
After receiving the desired values for rotation angles θ and ω, a plurality of angles associated with intersections of center axis 44, first wing axis 46, and second wing axis 48 may then be determined. These angles may include, among others, a resultant (i.e., compound) angle λ between center axis 44 and first wing axis 46. Angle λ may be determined using the law of cosines, based on the received values for θ and ω, in two consecutive applications. Once angle λ is determined, a resultant tilt angle δ of first wing axis 46 may then be determined with respect to center axis 44. Angle δ may be determined as a function of angle λ (e.g., δ=λ−180°. The next step may be to determine an angle σ between a horizontal plane of first wing section 38 (e.g., a plane formed by center and first wing axes 44, 46) and a global horizontal plane of moldboard 20 (e.g., a plane substantially parallel with ground surface 22 when moldboard 20 is assembled to machine 10). Angle σ may be based on the second direction of wing rotation ω designed to efficiently push material. Angle β, designated as the angle of intersection between a radius of center section 36 and a radius of first wing section 38, may then be determined as a function of the resultant tilt angle δ (e.g., β=δ−90). An angle α, which may determine the rotation of cut between center section 36 and first and second wing sections 38, 40, may then be determined as a function of σ (e.g., α=σ+35°).
Once these angles (and others) have been determined, three different cylinder unwrapping curves may be generated that can be used to create moldboard 20. The first cylinder unwrapping curve may be a sinusoidal curve generated by means of EQ 1 below that is subsequently used create one side of notch 56. The second cylinder unwrapping curve may also be a sinusoidal curve, and generated by means of EQ 2 below that is subsequently used to create outer geometry of moldboard 20 (i.e., the side and lower boundaries of moldboard 20). The third cylinder unwrapping curve may be generated by means of EQ 3 below and is subsequently used to create fold lines 58 between the different upper portions 42.
Notch Curvature=√{square root over ({r2−(r*sin [(x+rα)/r]2})}*(secβ+tan β)−r*tan β EQ 1
Curves for Outer and Bottom Edges=−tan β*[r sin(x/r)*cos α+√{square root over (r2−r sin(x/r)2)}*sin α] EQ 2
Fold Line Angle=(sec β+tan β)*(−sin α) EQ 3
Once the first sinusoidal curve has been generated using EQ 1 described above, the curve may be mirrored across fold line 58 of upper sections 42 (i.e., across the fold line angle found using EQ 3) to generate a paired sinusoidal curve used to form the opposite side of the same notch 56. These cylinder unwrapping curves, once determined via EQs. 1-3 described above, may then be plotted on the blank of metal used to fabricate moldboard 20, and the notches, boundary edges, and fold lines formed.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed moldboard. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed moldboard. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.