HK1185640A - Dragline bucket, rigging and system - Google Patents

Description

Dragline bucket, rigging and apparatus

The applicant is: the Escico company, filed for: on 21/1/2009, the application numbers are: 200980102544.6, the name is: divisional applications for inventions of buckets, rigging and devices for draglines.

Technical Field

The present invention relates to a dragline bucket, and in particular to a dragline excavating apparatus bucket.

Background

Dragline excavation apparatus have long been used in mining and earth moving operations. Unlike other excavators, the dragline bucket is controlled and supported only by wire ropes and chains. In operation, the stability and performance of the bucket must be derived to a large extent from the bucket structure.

In smaller buckets, the forces encountered in dragline operation are not large and the payload is small. With these buckets, the force and payload can be easily compensated without inhibiting work. Even if the small bucket is designed to be inefficient, the difference in its filling time is not large because the bucket capacity is small. However, as machine sizes, mine sizes increase and higher production is desired, the size of the bucket in which draglines work increases greatly over time. In today's mines, large dragline buckets on the order of 30 cubic yards or larger are common, and buckets as large as 175 cubic yards are used. In a large bucket, the paradigm of the design changes because the shear forces affecting the design of a smaller bucket significantly on the material to be excavated (e.g., the ground) become less important than the large loads placed on the large bucket. The expansion of these buckets and the large, heavy payload, and the very large forces applied by the drag chain during the digging cycle, all require different degrees of consideration. However, many bucket designs also follow imperfect old rules that do not optimize bucket digging performance. As a result, there are still a number of problems in today's dragline buckets.

Since there is no lever or hydraulic cylinder used to push the bucket into the ground, it is important that the bucket dig into and penetrate the ground as the haul line pushes the bucket toward the tractor. To maximize production, it is desirable to dig into the ground as quickly as possible. Many older buckets are made with heavy front ends to withstand the rigors of mining. This arrangement places the center of gravity on the upper front portion, which causes the bucket to tip forward over the teeth when pulled forward. The operator needs to handle these buckets with particular care to avoid tipping the bucket too far forward and over at its front end. Even if the bucket remains in the digging position, it will remain too far forward, causing the material to break severely during loading. In addition, large forces are required to pull such an inclined bucket through the ground, primarily due to the heaped soil mass. On the other hand, a bucket with a center of gravity further offset toward the rear wall would penetrate more gradually and more difficult, which results in longer fill times and reduced productivity. United states patent 4791738 to Briscoe discloses the concept of increased drag-induced tipping which reduces the risk of tipping of the bucket while facilitating better and more reliable penetration into the ground. Although this design concept improves dragline work, penetration of the bucket is still more gradual and shallow, so that to fill the bucket requires increased movement. FIG. 7 shows a generalized penetration profile P of a ground surface G of an example of a conventional bucket₁。

The dragline bucket has a bottom wall, two opposed side walls upstanding from the bottom wall and a rear wall at the rear ends of the side walls. The walls together form an open front end and a bucket cavity that collects the earth. A lip with digging teeth and shrouds passes across the forward end of the bottom wall to enhance penetration and digging and reduce wear of the bucket structure. The sidewalls are generally tapered from top to bottom and front to back to facilitate and accelerate pouring of the collected material. Incomplete dumping in a dragline bucket can cause the material to return to the next digging stroke. This problem not only requires hauling unnecessary weight but also reduces the yield per digging stroke, i.e. because old material remains in the bucket, less new material is collected.

In conventional buckets, the collected clumps of earth material are typically forced inwardly and upwardly by the tapered sidewalls through about one-half to two-thirds of the bucket's travel toward the rear wall, and then fall toward the bottom and rear walls. This heaping of material results in a mound of earth being formed towards the front end of the bucket. The formation of such a pile in the bucket requires an increase in the force on the dragline, a slowing of the filling speed and a gathering of material at the front end of the bucket. Once this mound reaches a certain mass, it begins to act like a bulldozer blade pushing material forward at the front of the bucket. Such soil heaps also typically result in a heaped heap being formed at the front of the bucket (i.e., the dirt heaped up and heaped forward at the front of the dragline bucket). In some operations, the mound may need to be periodically flattened with other equipment (e.g., a bulldozer) to avoid snagging and wearing on the draw cord. In other operations, a bulldozer or other implement is used to push the mound off of the tractor so that during digging operations, a suitable resistance is created at a location remote from the tractor so that the bucket can be fully charged before the end of travel through the digging stroke. That is, sometimes the bucket is loaded with a mound during the next excavation, and often these mounds are required in order to fill the bucket.

In modern dragline work, the conventional bucket itself is a massive structure in order to provide a large payload and to withstand extreme loads and stresses. To reduce wear, typically buckets carry various wear components, which further increase the weight of the bucket. Rigging to accommodate and control such large buckets is also cumbersome. The boom and tractor are designed to accommodate the maximum load that is a combination of the weight of the dragline bucket, wear parts, rigging, and excavated material within the bucket. The greater the weight of the rigging and dragline bucket, the less the volume of loaded earth material that remains within the dragline bucket. While some efforts have been made to reduce the weight of the rigging, most have been made only in small increments or have resulted in other undesirable problems.

In addition, the bucket and rigging components are exposed to the highly abrasive environment of dirt, rocks and other debris that abrade the rigging and dragline bucket when these components are in contact with the ground. The connections between the rigging elements also wear in these areas that bear against each other and are subjected to various forces. Therefore, after a period of use, the dragline excavating devices must be periodically serviced to inspect, replace or repair various components. There are many components in most modern installations that require such inspection, replacement or repair, and significant downtime is required to complete the required work. This downtime reduces production and reduces the efficiency of the dragline work.

Disclosure of Invention

This invention relates to an improved dragline bucket, rigging and apparatus and in particular, but not exclusively, to an improved dragline bucket, rigging and apparatus for large bucket work.

According to one aspect of the invention, a dragline bucket is formed with a new configuration that can collect earth material with minimal disturbance. This results in reduced forces and stresses on the bucket and equipment, increased payload, faster fill speeds, and less need for additional equipment in some operations.

In another aspect of the invention, the side walls, at least in the region of the front end of the dragline bucket, are provided with a large downward taper from the vertical, preferably about 7-20 degrees, to improve the collection of the earth material.

In another aspect of the invention, a dragline bucket has improved construction and performance by achieving an optimum balance of height to length ratio, sidewall taper, and hitch pin height to bucket height ratio. In a preferred construction, the bucket has a height to length ratio of about 0.4 to about 0.62, the top-to-bottom taper of the sidewalls is about 7 to about 20 degrees from vertical, and the ratio of the link pin height to the bucket height is at least about 0.3.

In another aspect of the invention, a dragline bucket may also be provided with improved construction and performance by optimizing the ratio of link pin height to bucket length and the ratio of link pin height to bucket height. In a preferred embodiment, a bucket having a capacity of at least 30 cubic yards is formed for operation in a mine having a drag line at a pull angle of 45 degrees or less below the mine car by having a ratio of hitch pin height to bucket length of at least about 0.2 and a ratio of hitch pin height to bucket height of at least about 0.3.

In a preferred construction of the invention, the dragline bucket includes an elevated coupling position of at least about one-quarter of the average height of the bucket. The use of a tall hitch facilitates deeper penetration and digging of the dragline bucket.

In another aspect of the invention, the side walls of the dragline bucket are tapered upwardly in the rear region of the bucket, eliminating the need for cross braces and their associated links and pins, while also connecting the hoist chain to the exterior of the bucket. This arrangement minimizes the disruption of filling and dumping of the bucket and avoids increased wear on the hoist chain or bucket. The hoisting chain can be used less by eliminating the transverse supporting rod. Thus, the overall weight of the bucket and rigging in the bucket arrangement is reduced and includes fewer components that require inspection and maintenance during use.

In another aspect of the invention, the side walls of the dragline bucket have a downward taper in the front region and an upward taper in the rear region. In one preferred construction, the transition section has a generally s-shaped configuration along the length of the bucket.

In another aspect of the invention, the dragline bucket operates according to a relationship wherein the ratio of (a) the hitch pin height multiplied by the drag force to (b) the length of the center of gravity multiplied by the weight of the bucket and payload is greater than or equal to about 1 during initial penetration and excavation and less than about 1 once the bucket reaches the desired penetration depth.

To enhance an understanding of the advantages and features of the invention, reference may be made to the following description and accompanying drawings that describe various structures and concepts related to the invention.

Drawings

The foregoing description and the following detailed description are better understood when read in conjunction with the appended drawings.

FIG. 1 is a perspective view of a dragline bucket according to the present invention.

Fig. 2 is a side view of the bucket.

Fig. 3 is a front view of the bucket.

Fig. 4 is a top view of the bucket.

Fig. 5 is a cross-sectional view taken along line 5-5 of fig. 4.

Fig. 6 is a side view of an alternative hitch.

FIG. 7 is a generalized penetration profile schematic illustrating a conventional bucket and a bucket according to the present disclosure.

FIGS. 8a-8c are schematic diagrams illustrating a generalized fill pattern for a conventional bucket.

Fig. 9a-9c are schematic diagrams illustrating a generalized fill pattern of a bucket according to the present disclosure.

FIG. 10 is a perspective view of a dragline implement including an alternative dragline bucket in accordance with the present invention.

Each of fig. 11 and 12 is a perspective view of an alternative bucket.

FIG. 13 is a top view of an alternative bucket.

FIG. 14 is a front view of an alternative bucket.

Fig. 15 and 16 are each side views of an alternative bucket.

FIG. 17 is a rear view of an alternative bucket.

Fig. 18 is a cross-sectional view taken along line 18-18 of fig. 15.

Fig. 19 is a cross-sectional view taken along line 19-19 of fig. 15.

Fig. 20 is a cross-sectional view taken along line 20-20 of fig. 15.

Fig. 21 is a cross-sectional view taken along line 21-21 of fig. 15.

FIG. 22 is a side view of a second alternative bucket according to the present disclosure.

FIG. 23 is a top half view of the second alternative bucket.

FIG. 24 is a half elevation view of a second alternative bucket.

Fig. 25 is a partial cross-sectional view taken along line 25-25 of fig. 23.

Detailed Description

The present invention relates to a novel and improved dragline bucket and apparatus with enhanced performance. The new design provides less damage to the earth and more efficient collection of the earth than conventional dragline work. While the design of the present invention is particularly suited for large dragline mining operations with bucket capacities of 30 cubic yards or more, its various aspects have several benefits over other dragline operations. In this application, the inventive aspects of the present invention are described with respect to some exemplary dragline bucket designs, but are useful with various bucket configurations. In addition, in the present application, relative terms such as front, rear, upper, lower, horizontal, vertical, and the like are sometimes used for ease of description. However, these terms are not to be considered absolute; during operation, the orientation of the dragline bucket can vary greatly.

In one preferred construction, a dragline bucket 10 according to the present invention includes a bottom wall 12, side walls 14 and a rear wall 16 defining a bucket cavity 18 (FIGS. 1-5) for receiving and collecting earth material during excavation operations. The front of the bucket is open and bounded by a bottom wall 12 and side walls 14. A lip 20 is provided along the front end of the bottom wall 12. The lip 20 may simply extend across the width of the cavity 18 between the side walls 14 or may be bent upwardly at its distal end 21 (as shown in figure 1) to form the front and bottom portions of the side walls. Various designs of digging teeth 22, shrouds 24 and vanes 26 are mounted along the lip to improve digging and protect the lip. The coupling 27 is fixed to the side wall 14 for direct or indirect connection to a hoist chain (not shown). Alternatively, the tabs 27 may be secured in front of or behind the position shown, or to the rear wall 16.

Cheek 28 projects upwardly from lip 20 to form most or all of the forward end of sidewall 14. In the illustrated embodiment, the arch support 29 and the connecting arch 30 are provided on top of the cheek plate 28. An anchor bracket 32 connected to a dump line (not shown) is supported on the arch 30. However, the arch may be omitted or formed in a different way, such as a linear tube arch. The members 20, 28, 29, 30 forming the front end of the dragline bucket 10 are collectively referred to as a bucket ring 34. In this application, the term bucket ring 34 is used for this front portion of the bucket, regardless of the arch shape or whether there is an arch. In order to withstand the severe conditions of excavation work, it is preferable that the bucket ring be made of a heavy member.

Side wall 14 is considered to be the entire side portion of bucket 10, which in this example includes arch support 29, cheek 28, end 21 of lip 20, and plate portion 35 extending between bucket ring 34 and rear wall 16. In one preferred construction, the side walls 14 taper downwardly (i.e., top to bottom) at an angle θ of at least about 7 degrees from vertical when the bucket is horizontal, and preferably in the range of about 7-20 degrees from vertical; that is, the side walls 14 converge toward each other at an included angle of about 14-40 degrees as the side walls extend toward the bottom wall 12 (FIG. 5). In the most preferred configuration, the sidewalls taper at about 9-15 degrees from vertical. In a preferred embodiment of bucket 10, angle θ is 9.6 degrees from vertical. In this configuration, for every 12 inches (30.5cm) of increase in the height of bucket 10, each sidewall 114 extends outward approximately 2 inches (5.08 cm).

While some conventional buckets have sidewalls that taper from top to bottom, the taper angle is smaller, making the sidewalls closer to vertical. The use of a greater sidewall taper provides additional side clearance for the collection of earth material in the bucket cavity 18 as the bucket penetrates the ground and fills. This increased side clearance (i.e., across the width of the bucket) reduces the disruption of the collected material and causes smaller mounds of soil and mounds of soil in the cavity 18, resulting in smaller or no mounds, and may also result in a greater density of material collected in the bucket cavity for a given lip size.

The lip 20 and the side wall 14 together form a front opening 58 (fig. 1) through which the earth material enters the cavity 18. The extension of the lip across the width of bucket 10 (i.e., the extension of lip 20 between sidewalls 14), along with its teeth 22 and shroud 24, creates a specific surface area that is first forced into the ground at the beginning of an excavation job. In general, while the shape and number of teeth, shrouds, and configuration of the lips may also affect the force required to drive the bucket into the ground, the greater the surface area of the lips and their respective ground engaging tools 22, 24, the more force is required to drive the bucket into the ground. All other things being equal, a shorter lip requires less force to penetrate the ground or, stated another way, it can penetrate into the ground faster and easier than a longer lip. By providing a more tapered sidewall 14 of about 7-20 degrees from vertical, the front opening 58 is larger for a given bucket width (i.e., across the lip) as compared to a conventional bucket with less or no sidewall taper. As a result, a bucket with a large top to bottom sidewall taper with a certain frontal open area is not only easier to fill because of the large side clearance, but also easier to dig into the ground because of the shorter lip. Following tooth breakage during overload, the leading edges of the cheeks are spaced too far laterally outward when the angle θ of the sidewalls exceeds about 20 degrees. This phenomenon greatly increases the drag on the bucket, slowing down the fill and reducing performance.

Preferably, the top-to-bottom taper of the side walls 14 relative to vertical is about 7-20 degrees throughout the length of the bucket 10. Additionally, in a preferred embodiment, the side wall 14 does not taper front to back (although such a taper could be provided). This configuration minimizes the disruption of the earth material collected in the cavity 18, allowing for faster, easier and improved bucket fill. However, even if not continuous over the entire length of the sidewall, a greater top-to-bottom taper of the sidewall may still be achieved. Although the use of a larger taper is preferred more broadly hereinafter, the use of a top-to-bottom sidewall taper of at least about 7 degrees from vertical in at least the dipper ring 34 may be of some benefit to the filling and penetration of the present invention. Additionally, even in the bucket ring 34, some portions of the side wall 14 may taper from top to bottom with respect to the vertical less than 7 degrees, so long as the side wall of the nose region (at least the ring portion 34) tapers primarily with respect to the vertical at least about 7 degrees. In any event, the front end region of the side wall tapers at least about 7 degrees from vertical greater across more than half of the span.

The side walls 14 form a top rail 60, and the top rail 60 may have various shapes. In the illustrated embodiment, the top rail 60 is generally a pair of line segments (fig. 1 and 2) that slope downwardly toward the rear wall 16. The top rail 60 determines the height of the bucket 10. The height H is defined as: (a) the vertical distance between the front edge 54 of the inner surface 52 of the bottom wall 12 that is connected to the lip 20 when the bucket is at rest on a horizontal surface and (b) the average position along the top rail 60, wherein (b) excludes (i) any vertical extensions 62 of the arch support 29 (or other dump rope support if the arch is omitted) and (ii) any portion that is cut back by the rear wall 16. FIG. 2 illustrates an exemplary height dimension H₁It becomes the set of height dimensions used to determine the average height H. Fig. 22 shows an example of the cut-away portion 264 of the bucket 200; while this cut is made by an inwardly sloping corner, the cut may simply be a cut top rail without the inwardly sloping corner. In a bucket with a substantially straight top rail, the average height may be determined by the CIMA standard for determining the average height in bucket capacity (CIMA is the association of manufacturers of the building industry, which is nowIs part of the device manufacturer association). In buckets with highly curved or other unconventional top rail shapes, the average position of the top rail needs to be calculated separately.

A coupling device 40 is formed at the front end of the cheek plate 28 to facilitate connection with a drag chain (not shown), and in this embodiment is constructed of multiple pieces (fig. 2). In this embodiment, cheek 28 projects toward the forward ends of lip 20 and tooth 22 to form a link element 36 at the forward end location, although other configurations are possible. Coupling members 36 are enlarged, substantially cylindrical structures that define vertical channels 37 for receiving connecting pins 38 that connect an extension 39 of the coupling device with each coupling member 36. The hitch extension 39 forms a horizontal channel 42 for receiving a hitch pin 43 that is connected directly or indirectly to the drag chain. Other additional configurations may also be used. For example, the coupling device 44 is a single coupling element, i.e., a laterally enlarged portion of the cheek plate 45 forming the horizontal channel 48 for receiving the coupling pin 49 may be used in place of the multi-piece coupling device 40 (fig. 6). In each case, it is preferred that the location of the hitch pin 43 or 49 be sufficiently forward so as to form a large angle (e.g., near or beyond a right angle) between the tip of the hitch pin, tooth or shroud, and the center of gravity of the empty bucket. The preferred angle and the exact size of the actual pour point depend on the material hardness, ground slope and pull angle of the pull cord. In this application, the term "drag line" refers to a straight line connecting the tractor and the dragline bucket (i.e., the hitch pin 43). The straight line may coincide with the pull cord and chain or, if the obstacle (e.g. a soil structure) requires the pull cord to be bent, may not coincide.

The coupling pin 43 is located above the bottom wall 16 by a height h of the coupling pin_pAt a distance h (fig. 2) of_pIs defined as: (a) the vertical distance (i.e., the same location used to determine height H) between the longitudinal axis 50 of the hitch pin 43 and (b) the front edge 54 of the inner surface 52 of the bottom wall 12 that connects with the lip 20 when the bucket is at rest on a horizontal surface. For this dimension and all dimensions and relationships discussed in this application, the bucket is considered to include all those used in digging workThere are wearing parts. Also for this dimension, if there is more than one horizontal hitch pin, the hitch pin is the horizontal pin in the hitch closest to the bucket. Any point along the front edge 54 may be used when the lip 20 generally follows a plane. If the lip is vertically curved, an average position may be used. Due to the height h of the coupling pin_pA vertical distance, whether using an extension of the hitch or whether the lip has a backhoe, spade, step-like or other non-linear shape, is not affected by the forward projection of the hitch pin.

In a preferred embodiment, the hitch pin 43 is placed high on the bucket to allow the bucket to better dump forward, making the penetrating motion sharper and faster at the beginning of the digging stroke. The higher coupling pin may create a greater moment of tilting the bucket about the tip of the tooth and/or shroud, digging the tooth into the earth and forcing the bucket deep into the ground. To achieve these benefits, the coupling pin 43 is placed at a coupling pin height h_pWhere it is preferably at least three teeth of bucket height H, i.e. H_pH.gtoreq.0.3, more preferably H_pThe ratio of the/H to the total weight of the catalyst is more than or equal to 0.5. But for some buckets this ratio can be as high as 1.0, or even higher.

As described above, attachment device 40 is comprised of attachment member 36 and attachment device extension 39. The hitch extension 39 includes a laterally enlarged portion defining a channel 42 for a hitch pin 43. Likewise, the coupling element 36 is constituted by a transverse enlargement of the cheeks 28 defining the passage 37 of the connecting pin 38. These laterally enlarged portions of coupling means 40 are referred to herein as coupling structures 66 (fig. 1-4). Likewise, the coupling means 44 is a laterally enlarged portion of the cheek plates 45 defining the coupling structure 68 (fig. 6). The hitch 40 connects the bucket 10 with a drag chain (not shown). In each digging stroke, the drag chain pulls the bucket toward the tractor. Due to the laterally enlarged configuration of the hitch 66 (or 68) and the hitch 40 (or 44) being connected to the drag chain, the hitch 40 (or 44) puts a limit on the depth of cut of the bucket. That is, the laterally enlarged link structure 66 (or 68) creates a greater vertical resistance against deeper excavation. The height of the hitch helps control the speed at which the bucket fills because the hitch resists the downward force applied by the lip and teeth during digging. If the bucket fills too quickly, the force required to pull the bucket exceeds the pulling capacity of a given machine. If the hitch is too low, the rate of flow of the material into the bucket is limited and the production is reduced. Another protruding portion of the drag chain connection (e.g., a link) may be used to limit penetration.

Therefore, a higher hitch position is preferred in order to dig deeper into the bucket. The bucket can be filled quickly when the bucket is deep into the ground, so that the bucket has good performance. The coupling height h is defined as: (a) the vertical distance between the front edge 54 of the inner surface 52 of the bottom wall 12 connected to the lip 20 (i.e., the same location used to determine the height H) and (b) the lowest location 70 of the hitch structure 66 of the hitch 40 when the bucket is at rest on a horizontal surface. In a preferred construction, the ratio of the hitch height H to the bucket height H is at least about 0.20 (i.e., H/H ≧ 0.2). The ratio of the coupling height H to the height H of the bucket 10 is more preferably ≧ 0.3, but may be greater than 0.5, and may even be up to 1.0 or greater.

The position of the center of gravity CG of the bucket and its payload (if any) may also affect the performance of the bucket. The center of gravity length l is: the horizontal distance between the forwardmost tip 78 of digging tooth 22 and the center of gravity CG of bucket 10 when the bucket is at rest on a level surface (fig. 2). The center of gravity CG of the present application is considered to be the center of gravity of bucket 10, with its payload (if any) within bucket cavity 18. In the illustrated embodiment, bucket 10 has a backhoe lip such that teeth 22 near side wall 14 project forward more than the more central teeth. In this embodiment, the length of the center of gravity l is calculated from the tip 23 of the outer tooth 22 near the side wall 14. In another bucket configuration in which the centrally located digging tooth 22 projects further forward than the other digging teeth (not shown), the center of gravity length l is calculated from the tip of the centrally located digging tooth. As the excavated material collects within the bucket 10, the length of the center of gravity/changes. The length of the center of gravity l of the bucket when empty is such that the bucket is ready for digging, i.e., the ground engaging tools and other wear parts are connected for use during operation.

Referring to fig. 1-5, bucket 10 is shown empty and the position of center of gravity CG corresponds to the actual position of the center of gravity of an empty bucket 10 with corresponding wear components. However, as the excavated material enters the cavity 18, the position of the center of gravity CG is shifted, i.e., the position of the center of gravity CG is offset from the initial position of the center of gravity of the bucket 10 as the excavated material is collected.

In dragline bucket 10, to achieve the desired dumping to get the bucket quickly deep into the ground, at the beginning of the digging stroke, the following relationship is preferred.

This relationship continues until the bucket reaches its desired digging depth. After the desired penetration depth is reached and the bucket is partially full, the relationship of these factors of the bucket preferably changes to the relationship that the bucket levels out to more continuously and stably fill the cavity 18.

In one example, the bucket moves from the first relationship to the second relationship when the bucket is approximately 20% full of earth material, although other amounts may be used for other bucket configurations. The second relationship is preferably maintained over the entire digging length of the bucket (i.e., a distance equal to the length of the bucket) or more. In other words, these two relationships can only be used to analyze the bucket when the payload is moving relative to the bucket. At or near stall, this relationship no longer applies. Although any unit may be used, the same unit must be used for both weight variables and both distance variables.

Assuming a coupling pin height h_pRegardless of whether excavated material is within the cavity 18, but when both relationships are calculated, the coupling pin height h_pThe value of (c) remains the same.

The drag force relates to the force required to overcome the excavated material collected by the bucket 10. In other words, the drag force is the force applied by the drag chain in the digging stroke pushing the bucket 10 through the excavated material. Generally, as excavated material collects within the bucket 10, the drag force increases. As a result, the value for the pulling force differs in each relationship.

As described above, the center of gravity length l changes when excavated material is collected in the bucket 10. As a result, the value for the center of gravity length l is largely different for each point in the excavation stroke. Although the position of the center of gravity CG begins to shift forward as the bucket begins to fill (i.e., the center of gravity length/begins to decrease), once the bucket reaches a certain fill percentage, the process reverses and shifts rearward (i.e., toward the rear wall 16). Given that the distance from the forwardmost tip of digging tooth 22 to center of gravity CG generally increases during most digging strokes due to the excavated material being collected within bucket 10, the value of center of gravity length l is generally greater for the second relationship than for the first relationship.

The bucket and payload weight variables used in the first relationship are the total weight of the bucket 10 when the bucket is empty and as the bucket begins to dig in and load. The bucket and payload weight variables used in the second relationship are the total weight of the bucket 10 and excavated material within the cavity 18 when the bucket 10 is full after the initial penetration. Thus, the values for the bucket and payload weights in the first relationship are less than the values for the combined weights in the second relationship. In both relationships, the bucket and payload weight include wear parts fixed to the bucket, but do not include rigging.

From the discussion above, the hitch pin height hp remains constant between the first and second relationships, while the drag force, the length of center of gravity l, and the bucket and payload weights vary, respectively. Although the drag force increases between the two relationships, the product of the length of the center of gravity l and the weight of the bucket and payload increases to a greater extent than the product of the drag force and the height of the hitch pin (i.e., sometimes not at the end of the digging stroke). Thus, in the present invention, the first relationship provides a value greater than or equal to 1, and the second relationship provides a value less than 1. The offset designed into this relationship allows the bucket to have one orientation to begin penetration and a different orientation to collect material after the initial penetration. In the present invention, in order to deflect the bucket from an inclined condition to a condition substantially horizontal to the digging plane (e.g., ground level), it is preferred to vary roughly from one relationship to another at the point where the bucket is at its desired depth. The engagement of the coupling structure 66 with the ground may also assist in shifting the bucket from a tilted condition to a horizontal condition.

In normal operation, because the earth is collected in the bucket, it is typically driven upward and inward. When the bucket is full, the post-collected material is driven up over the collected material, causing it to form a pile with the peak of the pile closer to the front end opening than the back wall. A continuous generalized fill pattern f1, f2, f3, f4 for a conventional bucket is shown in fig. 8a-8 c. The material that begins to enter the bucket generally forms a small mound in the cavity of the bucket. The afterloaded material is stacked on top of and in front of this starting stack, except for the material that collapses back from the top of the stack. This accumulation of collected material can cause a jam to further fill the bucket even if the rear portion of the bucket is not fully filled. The pile of material collected in the bucket and in the front of the bucket impedes further loading and greatly increases the force required to continue pulling the bucket through the ground. Additionally, when lifting the bucket for dumping, most of the material collected along the fill lines f3, f4 is lost from the front of the bucket. During lifting, the material built up in the front of the bucket, along with the material being significantly lost from the front of the bucket, can result in a built up pile being formed in the front of the bucket, which may require periodic flattening or pushing back with other equipment.

In a preferred dragline bucket, the bucket is initially tipped forward to quickly penetrate the ground to a deep dig location. In this way, each time the distance is increased, a greater depth of material can be loaded into the bucket, which is then pulled forward by the drag chain. Once the desired depth is reached and a certain minimum amount of material is loaded into the bucket (e.g., 20% full), the bucket is deflected to a level that feeds material into the cavity 18 relatively constantly. The automatic leveling of the bucket avoids digging too far into the ground to jam the bucket, avoids excessive drag forces, and helps load the earth with less disturbance-all of which can make the dragline more productive. When the bucket is loaded, the root of the bucket is in contact with the ground.

As seen in FIG. 7, the penetration profile P of the preferred embodiment of the present invention₂Indicating that penetration of the bucket is performed at a steeper angle than a conventional bucket of comparable size (at P)₁Represented) deeper into the ground. Using a deeper, relatively constant cut (i.e. after leveling) loading cavity 18 results in faster filling and minimizes material damage because the bucket can be loaded in large quantities into several substantially horizontal, solid layers for a large portion of the digging stroke. The sequential generalized fill patterns f5, f6, f7 in fig. 9a-9c indicate that the initial filling of the bucket with earth material f5 is more continuous and the layer of material is less disturbed as compared to the digging of a conventional bucket. The next material layer f6 begins to be driven upward, across the beginning or previously cut material, to form a new layer. The final loaded payload f7 is forced upward across the starting layers. As shown by the wavy lines, during loading, subsequent plies flatten out and displace the leading portion of the underlying ply. The material in the front-facing pile of the bucket, which does not cause trouble in industrial production, is accumulated in large quantities. In addition, since the material collected is less disturbed, the material in front of the lip shears off at a steeper angle than in conventional buckets, and therefore less material is lost when the bucket is lifted. This can reduce the pile or pile without bumps. The bucket of the present invention does not need to dig over the heaped heap in subsequent work to achieve full payload.

In general, the length L of dragline bucket 10 is a measure of the axial elongation of cavity 18 (FIG. 2). In general, in theory, a shorter bucket may fill up more quickly than a longer bucket, i.e., if all conditions are the same, a shorter bucket may fill up more quickly than a longer bucket of the same capacity due to the different lengths of travel that must be taken by the earth material to enter the bucket cavity. In addition, the length L of the bucket 10 also affects the stability, dump penetration capability, and digging performance of the bucket. It is generally recognized that digging performance and fill-up speed are highly complex processes that depend on many factors, including bucket structure, the material collected, the position of the bucket relative to the mine car, the slope of the ground surface being excavated, the form of ground engaging tool used, and the like. However, despite the influence of many factors, in the preferred bucket construction, bucket length is one factor to consider for achieving a higher performance bucket. Bucket length L is defined as: (a) the average position of the leading edge 72 of the lip 20 and (b) the last position 74 of the cavity 18 when the bucket is at rest on a horizontal surface. In a lip with a linear leading edge, any point along the leading edge can be used to determine the bucket length. In backhoes, shovels, arcs, steps or other lips with non-linear leading edges, the average position of the leading edge is used to determine the bucket length L. The rearmost portion 74 of bucket 10 is preferably in the middle of rear wall 16 in a generally curved concave configuration along its inner surface 76.

In conventional dragline buckets, the bulging of the earth material also loosens the material and its density is reduced compared to the pre-excavated density of the material. Even when the material forms a pile that prevents further filling and/or bulging, its overall density is still less compared to pre-excavated material. In the present invention, the theoretical concept is to bring the bucket into the ground without disturbing the material collected in the bucket. This is of course not possible in actual operation. However, damage to the collected material is minimized with the bucket of the present invention. The reduced damage creates a more dense payload than in a conventional bucket, so a large payload can be provided per excavation stroke.

Additionally, in conventional buckets, a common cross brace impacts the top of the bucket along the sidewall top rails. However, in the present invention, due to the faster penetration and filling speed, in some cases the bucket is dug into the ground and filled faster than if the hoist rope were slackened. This can reduce the impact of the spreader bar falling by as much as 90%.

With a dragline bucket having a combination of certain features, a desired digging profile P2 and fill patterns f5, f6, f7 (FIGS. 7 and 9) can be achieved. First, the sidewalls 14 of the bucket 10 are primarily tapered from top to bottom at least about 7 degrees from vertical, at least along the front of the bucket 10 and preferably along the entire length. Also, preferably, the top-to-bottom taper is in the range of about 7-20 degrees from vertical, more preferably about 9-15 degrees from vertical (FIG. 5). Second, the ratio of bucket height H to bucket length L (i.e., H/L) is within 0.4-0.62, preferably within 0.58-0.62 (FIG. 2). Third, the ratio of link pin height hp to bucket height H (i.e., hp/H) is preferably equal to or greater than 0.3, and more preferably equal to or greater than 0.5.

Generally, any bucket intended for any significant excavation above or below the mine car to a pull-cord no greater than about 25 degrees below the mine car preferably has a height to length ratio (H/L) at the upper end of the desired range (i.e., about 0.6 and most preferably 0.58-0.62). In a bucket intended primarily for digging where the pull rope is no more than about 40 degrees below the mine car and at the mine car height, the height to length ratio (H/L) is preferably about 0.5. A bucket having a height to length ratio in the lower region of the desired range (i.e., about 0.4) is preferably reserved for the deepest level of excavation below the mine car. In most cases, the height to length ratio (H/L) is preferably from 0.5 to 0.62, most preferably from 0.58 to 0.62.

Conventional dragline buckets have a top-to-bottom sidewall taper (although the angle is less than 7 degrees); the H/L ratio of the dragline bucket is 0.4-0.62; the height hp of the connecting pin of other dragline buckets is more than or equal to 0.3. However, a combination of these factors has not been used previously. The combination of these factors produces superior and unexpected results compared to conventional dragline buckets. The bucket of the present invention loads faster, the payload is larger (via greater degree of fullness and increased density of the payload) and requires less additional equipment to work (e.g., eliminating or reducing the heaped pile).

In a preferred embodiment, dragline bucket 10 also has a ratio of coupling pin height hp to bucket length L (i.e., hp/L) of at least about 0.2 (FIG. 2), and most preferably greater than or equal to 0.3. In addition, the ratio of the coupling height H and the average height H of the bucket (i.e. H/H) is preferably at least 0.2, most preferably at least 0.3. The ratio of the coupling height H and the average height H of the bucket may be as high as 1.0 or more.

For modern mining operations it is common to use large dragline buckets, i.e. buckets with a capacity of 30 cubic yards or more. Although large dragline buckets produce much higher volumes than small buckets, they also have a number of serious loading and stability problems due to the much higher loads and stresses placed on the bucket during operation and the longer fill times. In addition, the structural payload capacity of a large bucket tends to be small in weight per unit. As a result, in larger buckets, much more attention is required in order to produce a bucket that can work as efficiently as expected. These dipper buckets typically operate in a range where the pull rope is inclined no less than about 45 degrees to the height of the mine car and no more than about 30 degrees above the height of the mine car. Buckets according to the present invention and operating under these conditions can fill faster, require less power, increase payload per excavation stroke, cycle faster, have a low ratio of steel weight to payload weight, and in some cases can reduce or eliminate the additional equipment required to level a mound. Mines may also achieve more efficient mining plans or sequences.

While various aspects of the present invention are particularly well suited for use in large dragline mining operations, some benefits can be obtained even in a more limited manner by introducing these aspects into other dragline bucket operations. Aspects of the present disclosure may be used in smaller buckets, but generally have less impact on bucket performance. For some phosphate mining operations where the dredged material is mined as a slurry, by including aspects of the invention, some benefits may be obtained from dragline bucket operation. However, the benefits of using aspects of the present invention are limited due to the presence of water. In addition, some mining sites (e.g., some phosphate mines) have buckets that are drawn upward, steeply inclined up to 60 degrees from horizontal. In these structures, the design parameters are greatly different. For example, under these conditions, the pull rope generally needs to be closely aligned with the bucket center of gravity to prevent inadvertent pulling of the teeth out of the ground. However, features such as the greater downward taper of the sidewalls and the absence of cross braces (discussed more fully below) also provide some benefit to these buckets.

In another configuration, bucket 100 according to the present disclosure has a configuration in which the cross braces are removable from rigging 101 (FIGS. 10-21). Bucket 100 includes a bottom wall 112, a back wall 116 and a pair of side walls 114 that form a cavity 118 within bucket 100 that collects excavated material. Each sidewall 114 includes a front region 115, a central region 117, and a rear region 119. Lip 120 is provided with a plurality of digging teeth 122 that engage the ground to break up or remove the earth material that is then collected in bucket cavity 118. The arch 130 extends between the side walls 114 and over the lip 120, however the arch may be omitted. To couple bucket 100 to rigging 101, bucket 100 includes a pair of coupling devices 140, a pair of rear attachment points 127 (e.g., trunnions), and a pair of upper attachment points 129 (e.g., anchor brackets). More specifically, coupling device 140 is used to connect drag chain 102 to forward region 115 of side wall 114, rear connection point 127 is used to connect hoist chain 103 to rear region 119 of side wall 114, and dump line 107 is connected to arch 130 with upper connection point 129.

The structural features of bucket 100 are the same as described above for bucket 10, with sidewalls 114 tapering from top to bottom in front region 115. More specifically, the side wall 114 tapers in the forward region from top to bottom between the top rail 160 and the bottom wall 112 of the side wall 114, preferably at an angle θ of at least about 7 degrees from vertical. In a preferred example, the sidewalls are at an angle θ of about 14 degrees from vertical (fig. 19). However, as with bucket 10, sidewall 114 preferably has a top-to-bottom taper of about 7 degrees to about 20 degrees.

As shown in FIG. 21, bucket 100 also has a configuration wherein sidewalls 114 taper upwardly (i.e., bottom to top) in rear region 119, i.e., sidewalls 114 converge in an upward direction away from bottom wall 112 in rear region 119. The side walls preferably taper at approximately the full height of the rear wall 116, but may taper upwardly only a portion of their height. Attachment points 127 are fixed to the outer surface of side walls 114 in rear region 119 for direct or indirect attachment to hoist chain 103. Given that the portion of sidewall 114 in rear region 119 tapers inwardly toward top rail 160, hoist chain 103 is angled inwardly toward dump block assembly 105. In this way, no spreader bar is required to prevent excessive contact of the hoist chain with the bucket.

The sidewalls in conventional dragline buckets do not taper or do not taper top to bottom in the rearward region forming the hoist chain connection. To limit the extent to which the hoist chain grazes or contacts the side walls, the cross braces may be used to impart an outward angle to the hoist chain extending upwardly from the dragline bucket. Typically, a first pair of hoist chains extend upwardly from the dragline bucket in an outward angular direction to connect the cross braces, and a second pair of hoist chains extend upwardly from the cross braces in an inward angular direction to connect a dump block assembly, which may have an upper or auxiliary cross brace. However, in a power shovel arrangement using bucket 100, there are no main cross braces because of the bottom-to-top taper of sidewalls 114. Thus, tapering upward to portions of the side walls 114 in the rear region 119 may create a configuration in which the hoist chains 103 may be angled inward to limit contact or chafing with the side walls 114 in the absence of a main or lower cross brace.

By removing the transverse strut and its associated links and pins from the rigging 101, the number of components in the rigging is reduced. The overall length of hoist chain 103 is short compared to four separate hoist chains in a conventional dragline apparatus. Thus, by omitting the spreader bar and its links and pins, and by shortening the overall length of hoist chain 103, the overall weight of rigging 101 is reduced. Thus, the upward taper of the sidewall 114 has advantages, including: (a) a smaller number of links from member to member, (b) a reduced overall length of hoist chain 103, and (c) a reduced overall weight. In a large bucket, the weight reduction caused by these changes can be as much as 11000 pounds or more. The reduction in rigging weight can allow the use of buckets that provide a larger payload. Even a 1% increase in payload is a great advantage because some mines, in addition to maintenance and other such shutdowns, drag-shovel buckets are continuously operated 24 hours a day and 7 days a week.

The upward taper angle of the sidewall 114 in the rear region 119 can vary widely. The upward taper angle β of each side wall 114 from vertical when the bucket is at rest in a horizontal plane is preferably about 20 degrees, but may be in the range of about 15-25 degrees from vertical, or may be any angle generally sufficient to reduce contact between the hoist chain 103 and the side walls 114. Preferably, the bottom-to-top taper is limited as far rearward as possible, but far forward enough to avoid excessive contact or interference between the bucket and the hoist chain.

As shown in fig. 10-13, the portion of the sidewall 114 in the central region 117 has an outward taper and an inward taper to form a transition between a downward taper in the forward region 115 and an upward taper in the rearward region 119. (a) The combination of the downward taper of the sidewall 114 in the front region 115, (b) the transition of the portion of the sidewall portion 114 in the central region 117, and (c) the upward taper of the sidewall 114 in the rear region 119, forms a generally s-shaped curve along the length of the sidewall 114. Various other shapes may be used to form the transition. However, in central region 117, an advantage of the generally s-shaped curve or other generally curved or non-angled configuration is a smooth transition, which may reduce stress concentrations in bucket 100 and better loading and dumping.

Bucket 200 is a UDD type dragline bucket, i.e., it includes front and rear hoist ropes (not shown) to control the lift and attitude of the bucket (fig. 22-24). One example of a UDD bucket arrangement is disclosed in us patent 6705031. Bucket 200 has a bottom wall 212, side walls 214 and a rear wall 216. Lip 220 extends across the forward end of bottom wall 212 and preferably includes end 103 bent upwardly to connect with cheek plate 228. The cheeks 228 project forwardly to form the coupling means 244 as a laterally enlarged hub to define a horizontal channel that receives a coupling pin. An arch 230 extends between the side walls (although the arch may be omitted) and supports a joint 232 for connecting a front hoist chain.

The sidewall 214 preferably has a downward taper in the forward region 215 and an upward taper in the rearward region 219. The downward (i.e., top-to-bottom) taper is the same as described above for buckets 10 and 100. The upward (i.e., bottom-to-top) taper preferably extends only partially over the height of the side walls in the rear region of the bucket. In this structure, each side wall 214 includes an inwardly-slanted corner portion 225 that is a generally triangular plate. The corner section 225 is preferably inwardly inclined at an angle α of about 35 degrees, but may also be inclined at about 15-45 degrees. Unlike bucket 100, a central transition portion having an S-shaped or other shaped wall portion is not required, although a different central portion may be provided. In addition, it is preferable that the front portion extends to the corner portion 225. The remaining portion of the sidewall 214 outside the corner portion 225 preferably tapers downwardly at least about 7 degrees from vertical.

In one preferred construction, the sidewalls are inclined at an angle of about 14 degrees from vertical, but an inclination of about 7 to 20 degrees may also be used. The lower edge 231 of corner section 225 is preferably downwardly inclined to a joint 227 for connection to a rear hoist chain. The rear hoist chain preferably comprises front and rear attachment points 241, 243 of the rear hoist chain, depending on the excavation, but may have only one attachment point. The inward angling of corner sections 225 provides clearance for the rear hoist chains, so the cross braces may be eliminated to obtain the same benefits as described above for bucket 100. While the UDD dragline bucket 200 is described as having an upward taper formed with inwardly sloping corner portions, a full or partial height taper with a central transition portion as disclosed in the bucket 100 may also be formed. Likewise, the upward taper of bucket 100 may be formed by inwardly sloping corner portions as described for bucket 200. It is preferred that the inwardly angled corners minimize the extension of the taper from bottom to top. However, this configuration is most suitable for hoist chain attachment of buckets near the back wall. In a conventional dragline bucket (i.e., a non-UDD bucket), the hoist chain connection is typically placed at the distal front end to better balance the load on the dump line. In UDD buckets, the hoist chain connection may be at the far rear end because the attitude and dumping of the bucket is controlled by the front hoist rope rather than the dump rope.

In a dragline bucket, the various features of the present invention are preferably used together. These structures may be used in combination to maximize ease of operation and performance. However, the various features may be used alone, or in limited combinations to achieve some of the benefits of the invention.

The present invention is disclosed above and in the accompanying drawings in combination with various structures. The purpose served by the description, however, is to provide an example of the various features and concepts related to the invention, not to limit the scope of the invention. Those skilled in the art will recognize that many variations and modifications may be made to the above-described structures without departing from the scope of the present invention.

Claims (17)

1. A dragline bucket comprising: a bottom wall, a pair of side walls, and a back wall that together form a cavity for collecting the soil material, the cavity having a capacity of at least 30 cubic yards, each of said side walls including a front region, the side walls at least in the front region tapering substantially from the top of the cavity to the bottom wall so as to converge toward each other in a direction of the bottom wall at an angle of about 7 degrees to about 20 degrees relative to vertical.

2. The dragline bucket of claim 1 wherein the front region of each of the sidewalls is inclined at an angle of about 9 degrees to about 15 degrees from vertical.

3. The dragline bucket set forth in claim 1 wherein each of the sidewalls includes a rear region in which the sidewalls converge toward each other as the sidewalls extend away from the bottom wall.

4. The dragline bucket of claim 3 wherein the rear region of each of the sidewalls is at an angle of between about 15 degrees and about 20 degrees.

5. A dragline bucket in accordance with claim 1 having a height,

wherein a lip is secured to a front edge of the bottom wall, the bottom wall including an inner surface that is part of the cavity, and the lip including a leading edge,

wherein each said side wall includes a bottom edge connected to a bottom wall and a top rail opposite the bottom edge, the height being an average of the vertical distance between the inner surface of the bottom wall on the front edge and a top rail excluding any cutbacks on the rear wall and upward extensions of an arch support or dump cord support,

wherein each of said side walls supports a coupling pin for connection with a traction chain, the height of the coupling pin being the vertical distance between the inner surface of the bottom wall on the front edge and the longitudinal axis of the coupling pin, an

Wherein the ratio of the link pin height to the bucket height is at least about 0.3.

6. The dragline bucket of claim 5 wherein the bucket has a length, wherein the length is the horizontal distance between the average forward position of the leading edge and the final position of the cavity, wherein the ratio of height to length ranges between about 0.4 and about 0.62.

7. The dragline bucket of claim 6 wherein the height to length ratio is about 0.58.

8. The dragline bucket of claim 6 wherein the sidewalls do not taper front to back.

9. The dragline bucket of claim 6 wherein the ratio of the link pin height to the bucket length is at least about 0.2.

10. A dragline bucket in accordance with claim 5 wherein the ratio of the link pin height to the bucket height is at least about 0.5.

11. A dragline bucket in accordance with claim 1 having a length,

wherein a lip is secured to a front edge of the bottom wall, the bottom wall including an inner surface that is part of the cavity, and the lip including a leading edge,

wherein each of said side walls supports a coupling pin for connection with a drag chain, the coupling pin height being the vertical distance between the inner surface of the bottom wall on the front edge and the longitudinal axis of the coupling pin,

wherein the length is a horizontal distance between an average front position of the leading edge and a last position of the cavity, an

Wherein the ratio of the link pin height to the bucket length is at least about 0.2.

12. The dragline bucket of claim 11 wherein the ratio of the link pin height to bucket length is at least about 0.3.

13. A dragline bucket in accordance with claim 1 having a height and a length,

wherein each said side wall includes a bottom edge connected to a bottom wall and a top rail opposite the bottom edge, the height being an average of the vertical distance between the inner surface of the bottom wall on the front edge and a top rail excluding any cutbacks on the rear wall and upward extensions of an arch support or dump cord support,

wherein a lip is fixed to the front edge of the bottom wall and the lip comprises a front edge, the length being the horizontal distance between the average front position of the front edge and the last position of the cavity, and

wherein a ratio of the bucket height to the bucket length ranges from about 0.4 to about 0.62.

14. The dragline bucket of claim 1 wherein each of the sidewalls includes a first joint connected to a front hoist chain and a second joint connected to a rear hoist chain.

15. A dragline bucket in accordance with claim 1 including a height,

wherein a coupling means is supported on each of said side walls, said coupling means including at least one laterally enlarged coupling structure defining a channel for receiving a pin, each of said coupling structures having a lowermost point,

wherein a lip is fixed to the front edge of the bottom wall and the bottom wall comprises an inner surface being part of the cavity,

wherein the coupling height is defined as the vertical distance between the lowest point on the coupling structure and the inner surface of the bottom wall at the front edge,

wherein each said side wall includes a bottom edge connected to a bottom wall and a top rail opposite the bottom edge, the height being an average of the vertical distance between the inner surface of the bottom wall on the front edge and a top rail excluding any cutbacks on the rear wall and upward extensions of an arch support or dump cord support,

wherein the ratio of the coupling height to the bucket height is at least about 0.25.

16. A dragline bucket in accordance with claim 15 wherein the ratio of the coupling height to the bucket height is at least about 0.3.

17. The dragline bucket of claim 1 wherein the sidewalls do not taper front to back.