AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Innovation Patent Applicant(s): Bradken Resources Pty Limited Invention Title: AN EARTHMOVING BUCKET AND A METHOD OF MANUFACTURING AN EARTHMOVING BUCKET The following statement is a full description of this invention, including the best method for performing it known to me/us: 2 AN EARTHMOVING BUCKET AND A METHOD OF MANUFACTURING AN EARTHMOVING BUCKET Field of the Invention 5 The present invention relates to an earthmoving bucket and particularly, although not exclusively, to an earthmoving bucket for a hydraulic face shovel machine. Background of the Invention 10 A hydraulic face shovel machine can be equipped with an earthmoving bucket for moving material, for example for moving excavated material to a dump truck. Hydraulic face shovel machines are expensive pieces of equipment to use and maintain, and so any increase in the efficiency with which a 15 hydraulic face shovel machine can operate, such as by increasing the efficiency with which the earthmoving bucket can move material and/or the volume of material that the earthmoving bucket can hold, can increase profitability. 20 Summary of the Invention In accordance with a first aspect of the present invention, there is provided an earthmoving bucket comprising: a lip portion having a central region and end regions; a floor; and 25 opposed side walls, the floor extending rearwardly from the lip portion and being bound by the opposed side walls; wherein the floor has an internal concave surface that curves in two dimensions; and 30 a cross sectional shape of the lip portion is arcuate such that the central region is lower than the end regions relative to the side walls. 3331676_1 (GHNter) P88453AU.1 3 Having a lip portion curved in such a way provides the significant advantage of allowing the central region of the lip portion to engage material prior to the rest of the lip 5 during use, thereby improving the earthmoving bucket's ability to penetrate material. Further, a lip portion with an arcuate cross section provides the significant advantage of increasing the 10 structural strength of the earthmoving bucket. The lip portion may have a substantially constant radius of curvature. The lip portion may have an inner surface having an increased curvature at peripheral regions of the inner 15 surface so as to transition relatively smoothly to inner surfaces of the side walls. The lip portion may also have a profile such that the central region of the lip portion extends further outwardly 20 from the earthmoving bucket than the end regions of the lip portion. Such a profile provides the significant advantage of allowing the central portion, which projects further 25 outwardly than the peripheral regions, to engage material during use before the end regions, thereby improving the earthmoving bucket's ability to penetrate material. The lip portion may be arranged so as to receive teeth, such 30 as replaceable teeth. In one embodiment, wherein the lip portion comprises teeth, at least one tooth disposed at or adjacent the central region of the lip portion may extend 3331676_1 (GHMaNers) P88453AU.1 4 further outwardly than teeth disposed at or adjacent the end regions of the lip portion. In one embodiment, the lip portion is elongate and the inner 5 surface of the floor is curved about a first axis that extends substantially transversely of the lip portion; and about a second axis that is substantially parallel to the lip portion. 10 The curvature of the inner surface of the floor about the first axis may substantially compare to the curvature of the lip portion. Alternatively, the curvature of the inner surface of the floor about the first axis may substantially compare to the curvature of the lip portion at a region 15 adjacent the lip portion, and the curvature of the inner surface of the floor about the first axis may increase or decrease in a direction rearwardly of the lip portion. The inner surface of the floor may have an increased 20 curvature at end regions of the inner surface so as to transition relatively smoothly to the side walls. The curvature of the inner surface of the floor about the second axis may be such that drag on the earthmoving bucket 25 is reduced as the earthmoving bucket moves through material during a digging action. In one embodiment, the curvature of the inner surface of the floor about the second axis substantially follows a curve defined by the lip portion as the earthmoving bucket implements a digging action. 30 An outer surface of the floor may follow the curvature of the inner surface of the floor in both dimensions. 3331670_1 (GHMatters) P88453AU.1 5 The curvature of the inner surface of the floor and the curvature of the lip portion provides the significant advantage in that additional volume for receiving material 5 within the earthmoving bucket is provided compared to a conventional earthmoving bucket having a flat floor and a flat lip portion. By transitioning the inner surface of the lip portion and 10 the inner surface of the floor smoothly to the inner surfaces of the side walls, a significant advantage is provided wherein wear is more evenly distributed over regions corresponding to the transitions, as opposed to being concentrated at joins that would be provided between a 15 floor and side walls in a conventional earthmoving bucket. The earthmoving bucket may be arranged so as to receive wear plates, or any appropriate wear reducing protection. 20 In one example, the mining bucket is a hydraulic face shovel bucket. In accordance with a further aspect of the present invention, there is provided a method of manufacturing an 25 earthmoving bucket in accordance with the first aspect, the method comprising the steps of: forming a curved floor by casting, or by rolling a plate material; and joining the curved floor to the other elements of the 30 earthmoving bucket. 3331678_1 (GHMatters) P86453AU.1 6 In one embodiment, the curved floor is joined to side walls and a rear wall of the earthmoving bucket by welding. Casting the floor provides the significant advantage of 5 allowing a material from which the floor is cast to be selected from a larger range of materials than if the floor was formed using other methods. Forming the curved floor by casting provides the advantage 10 wherein maintenance issues associated with welding, for example if plate materials were used, are avoided. Brief Description of the Drawings In order that the present invention may be more clearly 15 ascertained, embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is an isometric view of an earthmoving bucket 20 in accordance with an embodiment of the present invention; Figure 2 is a front view of the earthmoving bucket of Figure 1; 25 Figure 3 is an isometric view of the earthmoving bucket of Figure 1 showing an outer floor surface of the earthmoving bucket; Figure 4 is a bottom view of the earthmoving bucket of 30 Figure 1; and 3331676_1 (GHhatters) P88453AAU-1 7 Figure 5 is a side cross sectional view of the earthmoving bucket of Figure 1. Detailed Description of the Embodiments 5 Referring to Figures 1 to 5, there is shown an earthmoving bucket 10 in accordance with an embodiment of the present invention. In this example, the earthmoving bucket 10 is for use with a hydraulic face shovel machine and comprises mounting means (not showm) for mounting on a hydraulic face 10 shovel machine. The earthmoving bucket 10 comprises a lip portion 12 which is arranged to receive a plurality of replacable teeth 14, and a floor 16 extending rearwardly from the lip portion 12. 15 The floor 16 is bound by opposing side walls 18 and a rear wall 20. In this example, the rear wall 20 is openable and is arranged so as to allow collected material to exit therethrough. 20 The lip portion 12 has a central region 22 and end regions 24. In this example, the lip portion 12 is elongate and has a cross sectional shape that is arcuate such that the central region 22 is further from a line 26 extending transversely of the earthmoving bucket 10 than the end 25 regions 24. In this way, teeth 14 that are disposed at the central region 22 of the lip portion 12 engage material, in use, prior to the teeth 14 disposed at the end regions 24. This 30 arrangement can assist the earthmoving bucket 10 to penetrate material. The curve of the lip portion 12 also 33316761 (GHMaU~t) P86453AU.1 8 assists in increasing the structural strength of the earthmoving bucket 10. The lip portion 12 in this example has a substantially 5 constant radius of curvature. Further, the lip portion 12 has an inner surface 13 having an increased curvature at end regions 15 so as to transition relatively smoothly to inner surfaces 19 of the side walls 18. 10 In one example, the lip portion 12 is curved such that the central region 22 deviates by approximately 500mm from the line 26, and the lip portion 12 has a length of approximately 5m as measured along the line 26. It will, however, be appreciated that the lip portion 12 could be of 15 any appropriate dimensions and curvature. The lip portion 12 also has a profile wherein the central region 22 of the lip portion 12 extends further outwardly from the earthmoving bucket 10 than the end regions 24. This 20 can best be seen in Figure 4. The teeth 14 are arranged on the lip portion 12 such that teeth 14 disposed at the central region 22 project further outwardly than teeth 14 disposed at the end regions 24. 25 This arrangement provides assistance when the earthmoving bucket 10 moves though material since teeth 14 disposed at the central region 22 will project further outwardly and can therefore, in use, engage material first and aid in penetrating the material. 30 Referring again to Figure 1, the floor 16 has a concave inner surface 28 that curves in two dimensions. The inner 3331676_ (GHMatters) P86453AU.1 9 surface 28 is curved about axis A such that it follows the curve of the lip portion 12 as the inner surface 28 extends rearwardly with the floor 16. The inner surface 28 is also curved about axis B, which is substantially perpendicular to 5 axis A. The curvature in two dimensions provides a substantially concave inner surface 28 that is well suited for receiving material, such as ground material collected using the earthmoving bucket 10. 10 In one embodiment, the curvature of the inner surface 28 about axis A is substantially similar to the curvature of the lip portion 12. In another embodiment, the curvature of the inner surface 28 about axis A is substantially similar to the curvature of the lip portion 12 at a region adjacent 15 the lip portion 12, and the radius of curvature of the inner surface 28 about axis A increases or decreases as the inner surface 28 extends rearwardly from the lip portion 12. Similar to the inner suface 13 of the lip portion 12, the 20 inner surface 28 has an increased curvature at peripheral regions 30 so as to transition relatively smoothly to the inner surfaces 19 of the side walls 18. The inner surface 28 may have a radius of curvature about 25 axis B such that drag on the earthmoving bucket 10 would be reduced, in use, as the earthmoving bucket 10 moves through material during a digging action. For example, the curvature of the inner surface 28 about axis B may substantially follow a curve defined by the lip 12 as the earthmoving 30 bucket 10 moves through a digging action. 3331676l (GHhanets) P88453AU.1 10 In this example, an outer surface 32 of the floor 16 follows the curvature of the inner surface 28 in both dimensions. This can further assist in reducing drag on the earthmoving bucket 10 as it moves through material. 5 The curvature of the inner surface 28 in two dimensions, and the curvature of the lip portion 12, provides the significant advantage of providing additional volume for receiving material within the earthmoving bucket 10 compared 10 to a conventional earthmoving bucket having a flat floor and a flat lip portion. As discussed above, the inner surface 13 of the lip portion 12 and the inner surface 28 of the floor 16 transition 15 relatively smoothly to the inner surfaces 19 of the side walls 18. This provides the advantage of reducing wear as the earthmoving bucket 10 moves through material as the wear is more evenly distributed over the end regions 15, 30 as opposed to being concentrated at joins that would be 20 provided between a floor and side walls in a conventional earthmoving bucket. The earthmoving bucket 10 can be arranged to receive wear plates, or any appropriate wear reducing protection, so as 25 to increase the durability of the earthmoving bucket 10. The floor 16 can be formed from cast material or from rolled plate materials. If the floor 16 is cast, then greater selection of materials is provided. Further, if the floor 16 30 is cast, then maintenance issues associated with welding are avoided. 3331676_1 (GHUatr) P88453AU.1 11 In accordance with an embodiment of the present invention, the earthmoving bucket 10 is manufactured in accordance with a first step of forming the curved floor 16 by casting or from rolling a plate material, and then a second step of 5 joining the curved floor 16 to the other elements of the earthmoving bucket 10 for example by welding the curved floor 16 to the side walls 18 and to the rear wall 20. Having described preferred embodiments of the invention with 10 reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments and that various changes and modifications could be effected therein by one skilled in the art without departing from the spirit or scope of the 15 invention as defined in the appended claims. In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, 20 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 features in various embodiments of the invention. 25 It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other 30 country. 3331576_1 (GHtUers) P88453AU.1