Implement system with nesting bucket and implement system operating method

An implement system includes a linkage and a bucket coupled with the linkage and movable between a dump position and a racked position. The bucket has a compound back section that forms a profile having a basin shape to assist in distributing material within the back section when the bucket is curled, and nesting the bucket close to the linkage. Related methodology is disclosed.

TECHNICAL FIELD

The present disclosure relates generally to buckets for capturing and moving material, and more particularly to a bucket back section profiled for distribution of material and nesting of the bucket with a linkage.

BACKGROUND

Wheel loaders, track loaders and other loading machines are equipped with buckets for the purpose of digging, loading and transporting all manner of different materials. Materials in a loose state such as sand, gravel, rock, soil, mulch, salt and still others are commonly moved about a worksite or from a pile into another machine for transport. One application at mine sites is the loading of blasted rock such as ore or overburden into a truck for disposal or transport to a processing site. A loader will typically drive into a pile of material with the bucket at a cutting or digging angle, generally but not always a horizontal bucket orientation, and then commence curling the bucket upon or slightly after entering the pile. The bucket is typically curled back to a racked position, the loader backs out of the pile, and then transports the bucket load to a dump site or into the bed of a truck. The same basic cycle can be repeated many times.

The overall efficiency of the process can vary dependent upon a number of factors, but in general it is desired to execute the capture and dump cycle as quickly as possible and with the bucket as full as possible. There can be tradeoffs in bucket filling versus cycle time that are managed to various ends. Moreover, the type of material and properties of the material or the pile itself such as particle size, moisture content, pile steepness, and still other factors can introduce variation and unpredictability to the manner in which the machine and bucket interact with the pile of material.

Those skilled in the art will be familiar with the wide variety of technologies developed over the years that attempt to improve upon the basic processes of loader operation and construction. Different bucket configurations, materials, and bucket construction techniques have been developed that are tailored to material type and/or loader operating environment, machine or implement system configurations, and other factors. U.S. Pat. No. 8,695,240 to Mills et al. is one example bucket design and entitled Machine Bucket Assembly. Mills et al. propose a bucket having a top section, a bottom section, and a curved middle section, with geometry configured to provide a loadability index within a target range.

SUMMARY OF THE INVENTION

In one aspect, an implement system for a machine includes a linkage, and a bucket for capturing a material, and including mounting elements coupling the bucket to the linkage, and the bucket being movable relative to the linkage between a racked position and a dump position. The bucket further includes a bucket shell having an upper edge, a roof section extending rearward from the upper edge, a lower edge, a floor section extending rearward from the lower edge and being oriented diagonally to the roof section, and a compound back section having the mounting elements located thereon. The roof section has a linear profile, the floor section has a linear profile, and the compound back section has a segmental profile. The segmental profile has a first curved segment transitioning with the linear profile of the roof section, a second curved segment transitioning with the linear profile of the floor section, and a linear middle segment transitioning from the first curved segment to the second curved segment, such that the segmental profile forms a basin shape, to distribute material within the compound back section and nest the bucket with the linkage at the racked position.

In another aspect, a bucket for an implement system in a machine includes a bucket shell having an upper edge, a roof section extending rearward from the upper edge, a lower edge, a floor section extending rearward from the lower edge, and a compound back section connecting between the roof section and the floor section. The bucket further includes a first side wall coupled with the bucket shell and a second side wall coupled with the bucket shell, and each of the upper edge and the lower edge extending between the first side wall and the second side wall. The bucket further includes mounting elements coupled to the compound back section of the bucket shell and structured to couple with a linkage. The roof section and the floor section each have a linear profile, and are oriented diagonally to one another to form a bucket throat, and the compound back section having a segmental profile including a first curved segment transitioning with the linear profile of the roof section, a second curved segment transitioning with the linear profile of the floor section, and a linear middle segment transitioning from the first curved segment to the second curved segment. The bucket is structured to pivot relative to the linkage between a dump position and a racked position, and the segmental profile forms a basin shape, such that material is distributed within the compound back section and the bucket nests with the linkage at the racked position.

In still another aspect, a method of operating an implement system includes capturing material with a bucket coupled to a linkage in the implement system, and tilting the bucket relative to the linkage from a digging position toward a racked position, such that captured material moves under the force of gravity through a throat of the bucket. The method further includes distributing material received from the throat in a compound back section of the bucket toward a first curved segment of the compound back section adjoining the roof section and toward a second curved segment of the compound back section adjoining the floor section. The method still further includes stopping the tilting of the bucket at the racked position such that a linear middle segment of the compound back section is adjacent an upper surface of the linkage and the bucket is nested with the linkage.

DETAILED DESCRIPTION

Referring toFIG. 1there is shown an implement system10according to one embodiment, and coupled with a machine12. Machine12may include a wheel loader or a track loader, for example, including ground engaging propulsion elements in the nature of wheels or tracks in a conventional manner. It is contemplated that applications where a machine is used to capture and dump loose or moderately cohesive material from a pile will particularly benefit from the teachings set forth herein, however, the present disclosure is not strictly limited to any particular machine configuration or material or work application. Implement system10may include a linkage14having a lift arm18and a tilt lever assembly20pivotably coupled with lift arm18. A bucket30including a plurality of mounting elements is pivotably coupled with lift arm16at a first location by way of a first one of the mounting elements32, and defining a pivot axis29, and at a second location by way of a second one of the mounting elements34, and defining a pivot axis28.

A lift actuator18is coupled between machine12and lift arm16and raises and lowers lift arm16. A tilt actuator26is structured to pivot tilt lever22between a first position at which a connector24coupled with tilt lever22pivots bucket30toward a dump position, and a second position at which connector24pivots bucket30toward a curled or racked position, approximately as shown inFIG. 1. Implement system10may be operated to capture, lift and dump material, such as loose rock at the toe of a blast zone at a mine, into a truck or the like. Bucket30is uniquely configured to advantageously receive material during operation, improving efficiency, and to nest with lift arm16, as further described herein. Bucket30has a front section36, and a back section38shaped so as to enable bucket30and thus the material therein to be positioned close to lift arm16. Back section38can be understood as compound, in reference to its shape, and also enables material to be distributed more readily at the back of bucket30, in turn making it easier in at least some instances for incoming material to enter bucket30, the significance of which will be further apparent from the following description.

One way the shape of bucket30can be characterized in at least certain embodiments is similar to what might be expected if a roughly parabolic-shaped bucket were squeezed down to deform the back section thereof in conformity with a flat surface. Such a shape has the tendency to have a center of gravity lower and closer to the lift arm in a bucket and linkage example similar to the example construction inFIG. 1. InFIG. 1, reference numeral300identifies an approximate center of gravity of bucket30, whereas reference numeral400identifies an approximate center of gravity of a known bucket design where the bucket has a shape that is generally parabolic. It can be seen that center of gravity300is located lower and closer to lift arm16than center of gravity400. Back section38of bucket30is positioned adjacent to an upper surface17of lift arm16.

Referring now also toFIG. 2, there is shown a perspective view of bucket30, illustrating back section38and also a first side wall40and a second side wall42coupled to opposite sides of back section38. Back section38is part of a bucket shell50, to which side walls40and42are coupled. A rock guard44extends upwardly and forwardly of bucket shell50. Cutting elements46also extend forwardly of bucket shell50. Also shown inFIG. 2are upper mounting elements34positioned at least in part upon back section38, and lower mounting elements32also positioned at least in part upon back section38. Mounting elements32and34pivotably couple bucket30to linkage14. Pivot axis34may extend through mounting elements34whereas pivot axis29may extend through one of mounting elements32. Linkage14may be equipped with hooks or the like structured to couple with pins supported within mounting elements32and34in a generally conventional manner. It should be appreciated that while the side view illustration ofFIG. 1depicts only a single lift arm, in a typical embodiment linkage14will include two parallel lift arms, with tilt lever assembly20being positioned generally between the parallel lift arms. In other embodiments, a single center lift arm might be used with two outer tilt lever assemblies, or still some other configuration.

Referring also now toFIG. 3, there is shown a view of bucket30illustrating certain additional features, including an upper edge52of shell50that extends between side walls40and42, and a lower edge54parallel to upper edge52and extending between side walls40and42. Guard44is coupled with upper edge52. A roof section56extends rearward from upper edge52, and a floor section58extends rearward from lower edge54. Floor section58and roof section56are oriented diagonally to one another so as to form a bucket throat76. Also shown inFIGS. 2 and 3is a lower slot62. Those skilled in the art will be familiar with the lowermost slot62and its relation to bucket payload volume calculations and bucket geometry, as further discussed herein. A ⅓ point line64is also shown extending across/through cutting elements46and also relates to certain geometric attributes of bucket30, as further discussed herein. It can be seen fromFIGS. 2 and 3that bucket30can be understood as having a width dimension extending in parallel with upper edge52and lower edge54, and a height dimension oriented normal to the bucket width dimension that is less than the width dimension. Certain of the geometric parameters to be discussed herein are in reference to an imaginary plane that includes the height dimension and is oriented normal to the width dimension.

As noted above, bucket30is shaped for enhanced distribution of material in back section38and also for nesting of bucket30with linkage14. To this end, roof section56may have a linear profile, floor section58may have a linear profile, and compound back section38may have a segmental profile. Features having a linear profile will be understood as having the appearance of a substantially straight line considered from at least one perspective. In the present instance, roof section56and floor section58appear straight and thus have linear profiles when viewed from the side, in other words where one is viewing one of side walls40or42straight on from a lateral side of bucket30. A segmental profile can include linear segments, but as a whole does not share this same property of a straight appearance when viewed from the side. Certain additional features and practical implementations of the possible shapes of back section38are further discussed below.

Referring now also toFIG. 4, there is shown a view of bucket30as it might appear where side wall42has been removed and an edge (not numbered) of bucket shell50is visible. Bucket30may include a forward plate66extending forward of floor section58, to which cutting elements46are attached but not shown in theFIG. 4view. Thus, cutting elements46are understood to be coupled to lower edge54by way of plate66. A wear plate68may be mounted upon bucket shell50on an upper side, and a paddle plate70is coupled to bucket shell50at a location rearward of cutting elements46and vertically below floor section68and defines a horizontal plane. Wedges72are positioned between shell50and paddle plate70in the illustrated embodiment. Floor section58and also wear plate68may be oriented at a floor angle74relative to the horizontal plane. InFIG. 4an arrow indicates an approximate direction of material flow that might be observed where bucket30impinges upon material in a pile at a neutral, horizontal position. It can be noted that floor angle74will result in material striking against floor section58at an angle, at least where bucket30is oriented with paddle plate70horizontal to an underlying ground surface. This feature contrasts with certain known bucket designs where a bucket floor and/or other features of the bucket were designed so that a bucket would more typically enter a pile with the floor horizontal.

Referring now also toFIG. 5, there is shown a side view of implement system10shown as it might appear where bucket30has been curled back to a racked position to capture material that has been dug from a pile, bank or the like. Back section38is positioned adjacent to lift arm16at the racked position. It will be recalled that back section30of bucket30is expanded relative to certain known designs, and according to geometric attributes still to be described herein. In general, the expanded back section can be understood to have a segmental profile that forms a basin shape, to distribute material within back section38and nest bucket30with linkage20at the racked position. InFIG. 5, arrows are shown illustrating an example tumbling flow of material such that the material is distributed toward roof section56and floor section58. It is believed that deconcentrating the volume of bucket30at back section38makes it easier for material to move out of the way as additional material is received in back section38from throat76during curling bucket30. The basin shape is considered to facilitate this general flow of material better than a parabolic shaped bucket. In a parabolic shaped bucket, material tumbling into the bucket may have a greater tendency to collide with other material and resist distribution within the back section of the bucket.

Regarding the nesting of bucket30, it can be seen fromFIG. 5that a first space78extends generally between bucket30and tilt lever assembly20. Another space80extends generally between bucket30and lift arm16. In certain earlier designs, spaces analogous to spaces78and80could be expected to be relatively larger as the different volume distributions of the bucket positioned the bucket center of gravity higher and more forward. The nesting of bucket30with linkage14enables the mass of material to be carried relatively closer to an associated machine, and can be expected to be associated with reduced strain on certain components and reduced wear, notably with respect to the tires. Many loader machines can operate a substantial portion of their service life carrying bucket loads and, accordingly, shifting load and bucket mass more towards the machine center of gravity can be expected to alter the weight distribution of the machine so as to cause significantly less intensive wear on the front tires.

As noted above, certain practical implementations have been developed relating to example specifications for various geometric features of bucket30. Referring also now toFIG. 6, there can be seen a first curved segment86of the segmental profile of back section36, the first curved segment86transitioning with the linear profile of roof section56. A second curved segment88transitions with the linear profile of floor section58. A linear middle segment90transitions from first curved segment86to second curved segment88, such that the segmental profile forms a basin shape. A basin shape can be understood herein to be wide and shallow, with curved walls and a generally flat floor. One of the walls might be higher or steeper than the other. Linear middle segment90may be oriented perpendicular to the linear profile of bucket floor58in certain embodiments, although in others a flat angle98formed between those segments might be relatively steeper or shallower, such as from about 60 degrees to about 130 degrees. The flat angle98will most typically be about 90 degrees or greater. Floor angle74shown inFIG. 4may be greater than zero, and in a further practical implementation strategy may be about 20 degrees or less. In still further instances floor angle74may be about 9 degrees or less. A first radius of curvature92defined by curved segment86may be different from a second radius of curvature94defined by curved segment88. Radius92will typically, but not necessarily, be less than radius94. A ratio of radius92to94may be from about 0.5 to about 1.5. Each of radiuses92and94may be defined in the imaginary plane mentioned above that includes the plane of the page inFIG. 6. A running length of curved segment86may be less than running lengths of each of curved segment88and middle segment90.

Bucket30may also have a setback configuration such that upper edge52is located rearward of lower edge54. In the embodiment illustrated inFIG. 6, a setback angle112may be about 90 degrees or less, and may be from about 55 degrees to about 90 degrees. A throat angle96may be from about 5 degrees to about 60 degrees. Setback angle112may be greater than throat angle96by a factor of about 1.5 or less. Embodiments are contemplated where setback angle112is about 60 degrees, and where throat angle96is about 40 degrees. Bucket30may further define a B-pin to ⅓ point dimension106and a B-pin to slot dimension104. InFIG. 6the B-pin location is shown via reference numeral102. The ⅓ point is shown via reference numeral100. A ratio of dimension106to dimension104may be from about 0.9 to about 1.4. A flat length dimension108is shown inFIG. 6, and a ratio of dimension108to radius94may be from about 0.25 to about 2.0. A flat height dimension110is also shown. Flat height dimension110may be about twice dimension108, or greater.

INDUSTRIAL APPLICABILITY

Referring to the drawings generally, in a typical operation machine12may be operated to drive into a pile of material with bucket30held at a generally horizontal digging position. Implement system10may be operated such that bucket30is tilted relative to linkage14from a digging position toward a racked position, such that captured material moves under the force of gravity through throat76. Material received from throat76can be distributed toward first curved segment86adjoining roof section56and toward second curved segment88adjoining floor section58. As described herein, greater ease of material falling and/or sliding out of the way is believed to make it easier for additional material to move through throat76and thus to enter and fill bucket30. As bucket30completes tilting and is stopped at the racked position, back section38will be positioned adjacent to linkage14and in particular lift arm16such that bucket30nests with linkage14.

These general principles of implement system operation and material flow can improve operation compared to known strategies, and in particular with regard to fill factor, generally defined as effective payload versus calculated and theoretical payload. Improved fill factor is associated with generally greater productivity, as each capture, lift and dump cycle of machine12moves a greater quantity of material. Moreover, the changed center of gravity as compared with other known bucket designs can reduce tire wear or wear on other components, and in some instances increase machine stability. A relatively shorter length of bucket floor58can provide a relatively greater breakout force, providing greater ease in breaking a load of material away from a pile and thus loading bucket30more rapidly.

Referring now toFIG. 7, there is shown a profile of bucket30in comparison with one known bucket design130having a back section with a profile that is different from a basin shape as in the present disclosure. In the known bucket130, rather than a wide and shallow profile with a generally flat floor, a trough is observed. While bucket130could perhaps have advantages in certain applications, it is likely the bucket130would be inferior with regard to distribution of material within its back section. Moreover, the trough shape in the profile of bucket130would likely be more labor intensive to manufacture, and would likely also prevent nesting of bucket130in the manner and to the extent to which bucket30is able to nest with linkage14. InFIG. 8, there is shown a profile of bucket30in comparison with another known bucket design230having a back section with a generally parabolic profile. As discussed herein, a parabolic profile can be expected to be inferior at least with regard to nesting of bucket230with a linkage, and also the distribution of material toward the back section of bucket230during curling to a racked position.

The present description is for illustrative purposes only, and should not be construed to narrow the breadth of the present disclosure in any way. Thus, those skilled in the art will appreciate that various modifications might be made to the presently disclosed embodiments without departing from the full and fair scope and spirit of the present disclosure. Other aspects, features and advantages will be apparent upon an examination of the attached drawings and appended claims.