AU2012100992A4 - Dragline Bucket - Google Patents

Abstract

A dragline bucket comprising an open enclosure with a forward facing mouth, the enclosure including a hitch s point at each side of the mouth, each hitch point comprising a boss containing a bush having a throughway to accommodate a hitch pin, whereby movement of the bush relative to the boss changes the position of the axis for the throughway. 34786811 (GHMatters) P87095.AU.1 29/06/12

Description

AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Innovation Patent Applicant(s): BRADKEN RESOURCES PTY LIMITED Invention Title: Dragline Bucket The following statement is a full description of this invention, including the best method for performing it known to me/us: - 2 DRAGLINE BUCKET This invention relates to a dragline bucket particularly for use in a dragline excavator in surface or 5 strip mining. Surface mining, sometimes known as strip mining, is a type of mining in which the soil and rock, the overburden overlying the mineral deposit are removed. The is usually io extracted by using very large excavating machines such as dragline excavators, buckets of which are filled with the overburden and then lifted clear of the mine. A typical dragline excavator includes a very large 15 crane that is mounted with its hoist extending over the mining pit. The hoist is coupled to a dragline bucket via a hoist coupling that extends down from the tip of the hoist and a dragline that is attached to the crane to drag the bucket across the mining pit to fill the bucket. 20 The bucket essentially comprises an open enclosure with an open front or mouth. The front of the bucket includes drag hitch points on either side joined by a vertically extending arch at the top of the bucket. A 25 pair of coupling mounts are positioned on either side of the bucket towards the rear of the bucket and a hoist coupler is coupled across the side mounts to the centre of the arch whilst the drag hitch points support a dragline. The front of mouth of the bucket defines a cutting lip, so 30 that as the bucket is pulled along the base of the mine pit, the lip scoops up material to be collected within the enclosure. It has been discovered that the efficiency of the 35 bucket is dependent on the position of the centre of gravity of the empty bucket, the design of the lip and the drag hitch location. It is known that there is a need to 3478681_1 (GHMatters) P87095.AU.1 29/06/12 - 3 vary the drag hitch location and there have, in the past, been attempts to provide alternate location points for the drag hitch. Other options include removing the hitch points and fabricating new hitch points to change and 5 alter the drag hitch location. These suggestions tend to increase the mass of the bucket and often require lengthy down time due to the cutting, welding and re-boring that has to be conducted on site to reposition the drag hitch locations. 10 It is these issues that have brought about the present invention. According to an aspect of the present invention there 15 is provided a dragline bucket comprising an open enclosure with a forward facing mouth, the enclosure including a hitch point at each side at the mouth, each hitch point comprising a boss containing a bush having a throughway to accommodate a hitch pin, whereby movement of the bush 20 relative to the boss changes the position of the axis of the throughway. The movement may be rotation of the bush relative to the boss or replacement of the bush with another bush with 25 a differently positioned throughway. Preferably each bush has an eccentrically located throughway, the bush being reversible or rotatable to vary the position of the axis of the throughway relative to the 30 boss. Preferably, the bush is welded within an aperture formed in the boss. 35 In accordance with a preferred embodiment the dragline bucket is secured to a dragline via chains coupled to shackles, the shackles being secured to the 3478681_1 (G HMatters) P87095.AU.1 29/06/12 - 4 bucket via the hitch pin. Preferably, each shackle has a pair of elongate links through which the hitch pin extends, the links terminate in a closed end, the distance between the axis of the hitch pin and the closed end being 5 sufficient to accommodate the movement of the hitch axis consequential to movement of the bush. The present invention will now be described by way of example only with reference to the accompanying drawings, io in which: Figure 1 is a side elevational view of a typical drag line excavator, Figure 2 is a side elevational view of a dragline 15 bucket, Figure 3 is a perspective view of the bucket from the front, Figure 4 is a perspective view of the bucket from the rear, 20 Figure 5 is a perspective view of an eccentric bush, Figure 6 is a perspective exploded view of a shackle and the bush, Figure 7 is a perspective view of the assembled shackle and bush, 25 Figures 8a and 8b are perspective and side elevational views of the assembly. Figure 1 illustrates a typical dragline excavator comprising a large crane C that is positioned at the edge 30 of a mining pit P. The crane C has a hoist H that extends over and into the mining pit. The hoist supports a dragline bucket 10 via a hoist coupler HC and a dragline DL. The crane C lowers the dragline bucket 10 into the base of the pit P and then the dragline DL pulls the 35 bucket 10 towards the crane C to fill up the bucket which is then lifted clear of the pit and transferred to suitable transport. 3478681_1 (GHMatters) P87095.AU.1 29/06/12 - 5 The dragline bucket 10 shown in Figures 2 to 4 essentially comprises a very large steel structure with an enclosure 19 designed by an open front 11, side walls 12 5 and 13, rear wall 14 and base 15. The top 16 of the bucket 10 is open and the front 11 includes drag hitch points 20, 21 on forwardly projecting arches 23, 24 on either side joined by a vertically extending arch 25 at the top of the bucket. A pair of coupling mounts 30 are 10 positioned on either side of the bucket towards the rear of the bucket and a hoist coupler (not shown) is coupled across the mounts 30 to the centre of the arch 25 whilst the drag hitch points 20, 21 support a dragline (not shown). The front 11 of the bucket defines a mouth 26 15 with a cutting lip 27 so that as the bucket is pulled along the floor of the mining pit the lip 27 scoops up material to be collected within the enclosure 19. It is known to provide vertically spaced hitch points 20 20, 21 on the forwardly projecting arms 23, 24 at the mouth 26 of the bucket. The user has the option of attaching the dragline DL via either pair of hitch points 20, 21. This structure, however increases the mass of the bucket and it is seldom that the users ever change the 25 location points. Other known buckets 10 have a single hitch point 20, 21 on each side again located in the forwardly projecting arm 23 or 24. This structure is lighter but can only have the hitch point location altered by removal of the forwardly projecting arms 23, 24 and 30 replacement with arms of a slightly different dimensions. The replacement of the arms is labour intensive and leads to considerable downtime. In the embodiment of this invention shown in Figures 35 2 to 8 the forwardly projecting drag hitch arms 23 and 24 are modified so that each arm 23 or 24 terminates in a boss 50 having a circular aperture 51. The circular 3478681_1 (GHMatters) P87095.AU.1 29/06/12 -6 aperture 51 is designed to accommodate a rotatable eccentric bush 52 that has an external wall 53 that is a sliding fit within the aperture 51 and an internal eccentrically positioned throughway 60 for location of a S pin 61 of a shackle 66. In Figures 5 to 8 the eccentric bush 52 is shown in a first orientation and is understood that the bush 52 would be welded to the boss 50 in that location. When there is a need to change the position of the axis of the shackle pin the weld between the eccentric 10 bush 52 and the boss 50 is broken and the bush 52 rotated to another orientation where the axis of the throughway 60 has been moved vertically by about 100mm. The bush 52 is then again welded to the boss 50 allowing the shackle 66 to be refitted. By making this change on both arms of the 15 bucket 10 the hitch location can be fine-tuned to ensure optimum operation of the bucket. Figures 6 to 8 show one arm of the bucket attached to a chain link 65 via the shackle 66. The shackle 66 has 20 parallel links 67, 68 joined at a closed end 69 which engages a chain link 75. The links have apertures 70, 71 to accommodate the pin 61 that extends through the apertures 70, 71 and the throughway 60 in the eccentric bush 52. The links 67, 68 of the shackle 66 have been 25 lengthened to accommodate the movement of the throughway axis. In another embodiment the bush 52 is a non rotatable fit within the boss 50. The location of the bush 52 can 30 be reversed to reposition the axis of the eccentrically positioned throughway 60. In a further embodiment the bush 52 is removed and replaced by another bush with a differently positioned 35 throughway 60 to change the position of the axis of the hitch pin. A series of replacement bushes with eccentric throughways could be used. The bush 52 would be 3478681_1 (GHMatters) P87095.AU.1 29/06/12 manufactured in an appropriately hardened steel. In the claims which follow and in the preceding description of the invention, except where the context 5 requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further 1o features in various embodiments of the invention. 3478681_1 (GHMatters) P87095.AU.1 29/06/12

Claims (5)

1. A dragline bucket comprising an open enclosure with a forward facing mouth, the enclosure including a hitch 5 point at each side of the mouth, each hitch point comprising a boss containing a bush having a throughway to accommodate a hitch pin, whereby movement of the bush relative to the boss changes the position of the axis for the throughway. 1o

2. The dragline bucket according to claim 1 wherein the throughway is positioned eccentrically of the bush so that the movement may be effected by either rotation or reversal of the bush relative to the boss.

3. The dragline bucket according to claim 1 wherein the is movement of the position of the axis of the throughway is effected by replacing the bush with another bush with a differently positioned throughway.

4. The dragline bucket according to any one of the 20 preceding claims wherein the bush is welded within an aperture formed in the boss.

5. The dragline bucket according to any one of the preceding claims wherein a dragline is secured to the bucket via chains coupled to shackles, the shackles 25 being secured to the bucket via hitch pins located in the throughways of the bosses. 34786811 (GH Matters) P87095.AU.1 29/06/12