The present disclosure relates generally to a loading apparatus for a machine such as a scraper, and relates more particularly to a machine such as a scraper having an auger loading apparatus.
A wide variety of building and similar projects require preparatory work such as leveling, grading and filling of underlying soil, gravel or other materials. Highway and building construction, for example, typically requires that a prepared bed of compacted work material be provided upon which pavement, concrete, etc. is to be laid. In some instances, material fill for such purposes must be brought to the work site from another location. In others, material must be removed or redistributed. Foundations for buildings, dams, airports, factories and other construction projects generally present similar issues relating to elevation profile, slope, proper work material type, etc. Virtually all civil, environmental and other construction endeavors require at least some work material transport, and it will thus be readily apparent that the capacity to move relatively large quantities of material in an efficient manner may be paramount for the success of many public and private works projects.
To move relatively large volumes of material, construction contractors often utilize machines known as “scrapers” to remove material from one location and transport it to another. The term “scraper” generally refers to the ability of the machine to remove an overlying layer of work material from a work surface. Typical machines employ a scraper blade or cutting edge which may be moved through work material beneath the machine to remove a top layer of material. The removed material is placed into a “bowl” of the scraper, then transported to a different work site or different area of a work site for deposition. Efficient loading and unloading of the bowl in scraper machines has long presented an engineering challenge.
Certain scraper machines, known in the art as open bowl scrapers, rely upon forward motion of the machine to urge work material removed with the scraper blade backward and upward into the bowl. This approach generally requires a relatively large and heavy machine to provide sufficient power for driving the machine, removing material, and filling the bowl of the scraper. The challenge is compounded by traction losses of the machine during such operation. In some instances, separate tractor machines are used to push or pull self-propelled and other types of scrapers to enhance their ability to load a desired volume of work material.
Engineers have developed certain strategies addressing the loading and unloading challenges experienced with traditional open bowl scrapers. In one design, an elevator apparatus having paddles is used to lift work material from the vicinity of the scraper blade upward, thenceforth dumping the material into the bowl. Elevator designs have met with significant success, however, the relatively large number of moving parts and overall complexity of the apparatus tends to result in high wear and significant maintenance issues. Elevator scrapers also tend to generate significant dust.
Another strategy employs one or more augers within the scraper bowl to distribute the work material after it enters the bowl in a more even fashion than that achieved with a conventional open bowl design. In such bowl and auger systems, rotation of a load-distributing auger can lift work material within the bowl and urge work material toward the sides of the bowl such that the scraper machine may more easily push additional work material into the bowl via its forward travel. While systems employing load-distributing augers have various advantages, including some conditioning and mixing of the work material, the auger tends to take up significant space within the volume of the bowl, limiting the carrying capacity of a scraper machine of a given size. Moreover, ejection of material from the bowl tends to be problematic as it must generally be moved around the auger. The ejector system itself can occupy a significant amount of bowl volume.
One example of a scraper machine having a load distributing auger is known from U.S. Pat. No. 3,533,174 to Carston. In Carston's design, an auger is positioned within the bowl of a scraper machine at a generally vertical orientation. The auger receives loosened material within the bowl from a cutting blade as the machine is moved forward. While Carston's strategy, provides certain advantages over open bowl scrapers, the design is subject to the same limitations mentioned above with respect to the bowl capacity. In other words, Carston' auger takes up a substantial amount of bowl volume that might otherwise be available for carrying work material. Thus, certain of Carston's potential advantages are at least somewhat overshadowed by the loss in work efficiency. Moreover, because of the auger's position, the machine still relies largely upon forward travel to push material into the bowl.
The present disclosure is directed to one or more of the problems or shortcomings set forth above.
In one aspect, the present disclosure provides a machine having a bowl mounted to a frame which defines a load volume. The machine further includes a cutter coupled with the frame and having a cutting edge, and a loading apparatus coupled with the cutter. The loading apparatus includes a chute with a first end disposed outside of the bowl and a second end. The loading apparatus further includes an auger disposed at least partially within the chute, and the auger is configured to move work material between the first and second ends of the chute.
In another aspect, the present disclosure provides a loading apparatus for a scraper machine. The loading apparatus includes at least one auger having an axis of rotation, a loading end and a second end opposite the loading end. The at least one auger defines a length dimension aligned with the axis of rotation that extends between the loading end and the second end. The loading apparatus further includes a chute that includes a material feed opening at a first position relative to the length dimension of the at least one auger, and includes at least one material discharge opening separate from the material feed opening and disposed at a second position relative to the length dimension which is different from the first position. The at least one auger is configured to move work material between the material feed opening and the discharge opening in a feed direction aligned generally with the axis of rotation of the at least one feed auger.
In still another aspect, the present disclosure provides a method of operating a scraper machine that includes a step of capturing work material at least in part via a step of moving a cutting edge of the scraper machine through the work material. The method further includes a step of moving work material into a chute of the scraper machine at least in part via the moving step, and a step of conveying work material from the guide chute to a bowl at least in part by rotating an auger disposed at least partially within the chute.
Referring to
Referring also to
Loading apparatus 30 may include a chute 38 having a first end 32 positioned outside of bowl 18, and a second end 33 through which work material may be conveyed during loading and/or unloading bowl 18. Chute 30 may further include an apron 39 extending from a material feed opening 42 outwardly toward cutter 20. Thus, work material removed from a work surface by cutter 20 may be guided via apron 39 toward and into material feed opening 42, and thenceforth discharged out of a material discharge opening 36 into bowl 18.
Loading apparatus 30 may still further include at least one auger 34 having an axis of rotation A. The at least one auger 34 is configured to feed work material in a feed direction between first and second ends 32 and 33 of chute 38. The at least one auger 34 may include first and second augers 34a and be 34b positioned in parallel. In one embodiment, augers 34a and 34b may comprise counter-rotating augers having blades 35a and 35b with overlapping peripheries. The augers are positioned in parallel, and configured to feed work material through chute 38 during either loading or unloading of bowl 18. An approximate feed direction for loading is shown via arrows B in
Turning to
Referring also to
In another embodiment of a loading apparatus 130, shown schematically in
Referring to the drawing Figures generally, during a typical loading operation, machine 10 will be driven across a work surface at as first work area, and cutter 20 and hence cutting edge 22 lowered to a desired vertical position such that cutting edge 22 will pass through work material, dislodging material from the work surface. Continued forward motion of machine 10 will result in additional material dislodged by cutter 20 being pushed upward and backward from cutting edge 22 and into chute 39, capturing the work material and beginning to load the same. Prior to or upon beginning to move cutter 20 through the work material, rotation of augers 34a and 34b in first and second directions may be initiated. Because augers 34a and 34b will typically be counter-oriented, e.g. having respective “left-handed” and “right-handed” helical configurations, they will typically be rotated in opposite directions during loading of bowl 18, but each urging work material in approximately the same feed direction, toward bowl 18 from cutter 20.
Work material pushed upward and rearward toward and into chute 38 will typically flow generally in two paths defined by curving surfaces 39a and 39b toward left and right sides of material feed opening 42. Approximately one half of the work material captured via cutter 20 will generally be fed toward first auger 34a, and one half fed toward second auger 34b. At material feed opening 42, rotation of augers 34a and 34b will generally rotate a cutting edge 53a and 53b at the loading ends 37 of each respective auger 34a and 34b against work material, and the work material will begin being conveyed through the portion of chute 38 defined by peripheral walls 50. Conveying of work material with augers 34a and 34b will tend to reduce the power necessary to continue to move machine 10 forward through the work material as compared to certain other designs. In particular, rotation of augers 34a and 34b performs a substantial portion of the loading work, rather than relying solely or mostly upon forward motion of the machine to push the work material into bowl 18.
When bowl 18 is relatively empty, work material will tend to be discharged via a portion of material discharge opening 36 that is located relatively close to front side 29 and bottom side 28 of bowl 18. As filling of bowl 18 progresses, material discharge opening 36 will tend to become partially blocked by deposited work material, and additional work material will be discharged relatively more upward and backward in bowl 18. This phenomenon results at least in part from the relative positioning of loading apparatus 30 in front of bowl 18, and its relative inclination. In one embodiment, the axis of rotation A of augers 34a and 34b may be oriented diagonally, for example at approximately a 45° angle, relative to articulation axis J. It is contemplated that an angle of approximately 45° may provide a desired balance between upward lifting force and backward loading force on work material conveyed by loading apparatus 30. For certain applications, and for certain machine designs, a different angle of inclination of axis A relative to axis J may be appropriate, and the augers may not be oriented in parallel. Where bowl load volume is to be maximized for a particular machine design or size, a loading apparatus 30 may be configured such that augers 34a and 34b are relatively more vertical, whereas when available power for pushing work material backward in bowl 18 is sought to be maximized, for example, for a relatively less powerful or lighter machine, a relatively more horizontal inclination of axis A may be appropriate.
When bowl 18 has been filled to a desired extent, cutter 20 may be lifted to substantially close bowl 18, and machine 10 will typically be driven to a second work area, for example, where work material is to be deposited. To deposit work material, cutter 20 may be lowered to a height corresponding to a desired lift thickness for deposited material. Machine 10 may then be driven across a work surface at the second work area, and augers 34a and 34b rotated in opposite directions to those used for loading bowl 18, to convey work material from bowl 18, through chute 38, and onto the work surface. During deposition of work material with machine 10, ejector apparatus 24 may be used to push work material toward front side 29 of bowl 18. Unloading of bowl 18 may thus take place in a manner generally the reverse of that occurring during loading. In other words, when bowl 18 is at least partially filled, work material may block a portion of material discharge opening 36, and thus material initially discharged via material discharge opening 36 will tend to be material that is positioned at relatively higher vertical positions in bowl 18. As unloading progresses, work material that is positioned progressively lower in bowl 18 will be discharged.
The presently disclosed design for a loading apparatus 30, 130 for use in a scraper or other material capturing machine 10 improves operating efficiency over known designs such as open bowl scrapers and auger scrapers wherein the augers are positioned within the bowl and thus reduce potentially available bowl volume. Rather than distributing work material within the bowl as in conventional auger-scraper designs such as Carston, augers 34a and 34b are used to convey work material into and out of the bowl without sacrificing bowl volume. This approach also allows easier loading, as the conveying power provided by augers 34a and 34b reduces the force necessary to move material into the bowl. Augers 34a and 34b can also carry material relatively higher into the bowl than conventional designs, as they do not have to overcome remolding forces associated with surrounding work material. In other words, in a design such as Carston, work material once distributed by the auger will tend to move back around the auger as bowl filling progresses, resisting efforts to pile material higher in the bowl, and also providing resistance to rotation of the auger.
With regard to conventional elevator scrapers, the present disclosure provides still other advantages. The present disclosure provides a system wherein the work material is better confined during conveying to the bowl, and may thus produce less airborne dust than elevator scraper systems. Moreover, expense, complexity and maintenance problems associated with elevator scraper designs are obviated, as machine 10 and loading apparatus 30, 130 may use a relatively smaller number of parts than elevator scrapers having track or chain driven paddles and the like.
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 of the present disclosure. For example, while the present disclosure is discussed primarily in the context of mobile scraper machines, it is not thereby limited. Those skilled in the art will appreciate that other types of material capturing and/or transfer apparatus such as are used in mining, agriculture and other activities may benefit from the teachings of the present disclosure. It should also be appreciated that while material discharge opening 36 is shown as an elongate, generally rectangular opening, and openings 136 are shown as spaced apart squares, the present disclosure is not thereby limited and slots, circular openings or some other configuration or positioning might be used. Other aspects, features and advantages will be apparent upon an examination of the attached drawings and appended claims.
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