AU748243B2 - Boom suspension assembly - Google Patents

Description

1 BOOM SUSPENSION ASSEMBLY FIELD OF THE INVENTION This invention relates to mining shovels, and more particularly to a kneeaction mining shovel with a boom supported by suspension cables.

DEFINITIONS

In the specification the term "comprising" shall be understood to have a broad meaning similar to the term "including" and will be understood to imply the inclusion of S" 10 a stated integer or step or group of integers or steps but not the exclusion of any other *eD

S

integer or step or group of integers or steps. This definition also applies to variations on the term "comprising" such as "comprise" and "comprises".

BACKGROUND OF THE INVENTION 15 A conventional mining shovel generally includes a base supported by ground engaging tracks. The base rotatably supports a frame on which is mounted a housing for protecting mining shovel components, such as power generation equipment, electrical equipment, a dipper hoist, and controls. The frame also supports a dipper assembly and boom. The dipper assembly includes a dipper which engages the ground.

The boom on a rope hoist mining shovel locates and supports boom point sheaves, over which pass hoist ropes from the hoist machinery to the dipper. When viewed from the side, the conventional boom structure generally lies on a line between the boom lower end connected to the frame, and the center of the boom E point sheaves. Suspension cables support the angular position of the boom, and aligned with the boom.

2 It is necessary that the boom be designed to withstand side loads imposed upon the load during mining operation. As a result the boom generally is heavy and formed from expensive material to withstand the side load. Clearly it would be advantageous if a boom suspension system could be devised that could counteract side loads on the boom. This would enable a mining shovel with a lighter weight boom to be used which is less expensive to produce.

.SUMMARY OF INVENTION The present invention provides a mining shovel including a frame having an upwardly support member. A boom extends upwardly and forwardly from the frame from a connecting end toward a distal end along a boom longitudinal axis. At least one first suspension cable has one end attached to the boom, proximal the boom distal end and an opposing end attached to the support member. The at least one S first suspension cable defines an angle relative to the boom longitudinal axis, S. 15 wherein in tension, the at least one first suspension cable resists a first side load imposed on the boom.

In another aspect of the invention, a boom suspension assembly for supporting a distal end of a boom includes a boom point box having a longitudinal axis. The longitudinal axis is parallel to a longitudinal axis of the boom when the boom point box is fixed to the distal end of the boom. A first lug is fixed to the boom point box, and defines an angle greater than 0 degrees relative to the boom point box longitudinal axis.

Thus a mining shovel is provided that provides side load stability to the boom while enabling the boom weight to be reduced. This is achieved by the suspension 1les which counteract side loads applied to the boom.

3 An advantage of the preferred forms of the invention is that they reduce the weight of the boom point box by aligning the lugs connected to the angled suspension cables to reduce the side loads on the lugs imposed by the angled suspension cables.

A boom suspension assembly and a mining shovel in accordance with the invention may manifest itself in a variety of forms. It will be convenient to hereinafter described in detail one preferred embodiment of the invention with reference to the accompanying drawings. The purpose of providing this detailed description is to instruct persons having an interest in the subject matter of the invention how to carry 10 the invention into practical effect. It is be clearly understood however that the o specific nature of this detailed description does not supersede the generality of the preceding broad description.

o oooo S° BRIEF DESCRIPTION OF THE DRAWINGS ooooo Fig. 1 is a perspective view of a mining shovel incorporating the present oooo o invention; Fig. 2 is a perspective view of boom point box of the mining shovel of Fig. 1; and Fig. 3 is a top view of the boom point box of Fig. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A knee-action mining shovel 10, shown in Figs.l-3, includes a base 12 supported by ground engaging tracks 14. The base 12 rotatably supports a frame 16 on which is mounted a housing 18 for protecting mining shovel components, such as power eneration equipment, electrical equipment, a dipper hoist, and controls. The frame 16 a ssupports a gantry 20, dipper assembly 22, and overhead boom 24. A dipper assembly 22 is pivotally connected to the frame 16, and supports a dipper 26 for engaging the ground. A gantry 20 is fixed to the frame, and extends above the housing 12. An overhead boom 24 is pivotally connected to the gantry 20, and extends over the dipper assembly 22. The boom 24 supports hoist rope sheaves which guide hoist ropes 28 attached to the dipper 26.

[0016] The dipper assembly 22 includes a stiff leg 48 having a lower end pivotally connected to the frame 16 with pins 49 and an upper end 54 pivotally connected to a dipper handle 52. The stiff leg 48 is pivoted about the pins 49 by a crowd handle 53 to move the dipper handle in a forwardly or rearwardly direction.

[0017] The dipper handle 52 is a beam extending forwardly from the stiff leg 48 having a connecting end 70 pivotally connected to the stiff leg upper end 56, and a dipper end 72. The dipper end 72 extends away from the frame 12 below the boom 24, and is connected to the dipper 26. Preferably, the dipper handle connecting end 70 is connected to the stiff leg upper end 56 by a universal joint to allow rotation about the "dipper handle longitudinal axis.

[0018] The dipper 26 is pivotally connected to the dipper end 72 of the dipper handle 52, and engages the ground to extract minerals and the like. The dipper 26 is a bucket, such as well known in the art for mining shovels. The dipper 26 is guided in the forwardly and rearwardly directions by the dipper handle 52, and is raised and lowered by the hoist ropes 28 suspended from the boom 24. Although pivotally connecting the dipper 26 to the dipper handle 52 is preferred, the dipper 26 can also be rigidly connected to the handle 52 without departing from the scope of the present invention.

[0019] The hydraulic crowd handle 53 pivots the stiff leg 48 about the pins 49 to move the dipper handle 52, and thus the dipper 26, in a forwardly and rearwardly direction. The crowd handle 53 has one end 55 pivotally connected to the gantry and an opposing end 57 pivotally connected to the stiff leg 48 proximal the stiff leg upper end 54. Actuation of the hydraulic crowd handle 53 pivots the stiff leg about the pins 49. Although a hydraulic crowd handle is disclosed, other crowd handles known in the art, such as a rack and pinion driven crowd handle, a rope driven crowd handle, and the like, can be used without departing from the scope of the present invention.

[0020] The boom 24 is an overhanging structure pivotally connected to the gantry 20, and supports the dipper 26 above the ground. The boom 24 has left and right legs 94, 96 pivotally connected to the gantry 20 above the stiff leg lower end and has a distal end 86 extending forwardly over the dipper 26. An area 98 between the left and right legs 94, 96 is open, which allows the stiff leg upper end 54 to slip between the side legs 94, 96 when the stiff leg upper end 54 is pulled by the crowd handle 53 to a maximum rearward position. A boom point box 42 welded to the legs 94, 96 at the boom distal end 86 ties the legs 94, 96 together.

[0021] The boom 24 extends upwardly from the gantry 20 along a longitudinal axis 87, and is held in its angular position by left and right upper suspension cables 88, 89. Each suspension cable 88, 89 has one end 90 attached to a lug 36 fixed to the gantry 20 and an opposing end 92 (shown in Figs. 2 and 3) attached to a lug 38 fixed to the boom point box 42.

[0022] Importantly, the suspension cables 88, 89 are strung at an angle relative to the boom longitudinal axis 87 to provide boom side stability. In particular, two cables 88, 89 are strung at an angle outwardly from each boom point box lug 38 toward one of the lugs 36 fixed to the gantry 20. The gantry lugs 36 are spaced further apart than the boom point box lugs 38 to cause the cables 88, 89 to form an angle B with the boom longitudinal axis 87 which is greater than 0 degrees, such as greater than 5 degrees. Preferably, angle B is greater than 7 degrees.

[0023] In tension, the angled cables 88, 89 counteract side loads imposed on the boom 24 during the operation of the shovel 10. In particular, the left suspension cables 88 counteract a side load imposed on the boom which is in a direction opposite to a side load counteracted by the right suspension cables 89. Advantageously, stringing the suspension cables 88 at an angle to the boom 24 minimizes the potential for interference between the suspension cables 88 and the hoist ropes 28. Preferably, the angled cables 88, 89, and thus the boom point lugs 38, define lines 91, 93 which intersect within the perimeter of the boom point box structure to avoid inducing a moment on the boom 24.

[0024] As shown in Figs. 2 and 3, the welded-on boom point box 42 incorporates both the boom point sheaves 25 and suspension cable lugs 38 to reduce the bending moment on the connection between the boom point box 42 and legs 94, 96, and has a longitudinal axis substantially parallel to the boom longitudinal axis 87.

The boom point box lugs 38 are fixed, such as by welding to a top surface 44 of the boom point box 42, at the angle B aligned with the cables 88 attached thereto to eliminate side loads on the lug 38, and thus reduce the structural weight of the lug 38.

The cables 88 are attached to the lugs using methods known in the art, such as yokes 46 fixed to a cable end and bolted to the lug 38.

[0025] The boom point sheaves 25 are rotatably mounted to the boom point box 42 above the dipper 26. Each sheave 25 supports one of the hoist ropes 28 -6attached to the dipper 26. Each rope 28 is attached to a dipper side, passes over one of the boom point sheaves 25, and is wound up on a dipper hoist. The hoist winds and unwinds the hoist rope 28 to raise and lower the dipper 26 using a single part hoist reeving method. Preferably, each hoist rope 28 is a wire rope sized using methods known in the art, for the particular application, which depends upon the dipper duty and capacity rating.

[0026] While there has been shown and described what are at present considered the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention defined by the appended claims.

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Claims (14)

1. A mining shovel comprising: a frame having an upwardly extending support member; a boom extending upwardly and forwardly from said frame from a connecting end toward a distal end along a boom longitudinal axis; at least one first suspension cable having one end attached to said boom proximal said boom distal end and an opposing end attached to said support member, said at least one first suspension cable defining an angle relative to said boom longitudinal axis, wherein in tension said at least one first suspension cable resists a first 10 side load imposed on said boom.

2. The mining shovel as in claim 1, in which said cable one end is spaced .:oooi from said boom longitudinal axis a first distance and said cable opposing end is spaced oo •o from said boom longitudinal axis a second distance, wherein said second distance is oo: greater than said first distance.

3. The mining shovel as in claim 1 or claim 2, in which a boom point box is fixed to said boom distal end, and said cable one end is attached to a lug fixed to said boom point box.

4. The mining shovel as in claim 3, in which said lug is aligned with the angle of said cable.

The mining shovel as in any one of claims 1 to 4, including at least one second suspension cable having one end attached to said boom proximal said boom tal end and an opposing end attached to said support member on an opposite side 9 of said longitudinal axis as said first suspension cable, said at least one second suspension cable defining an angle relative to said boom longitudinal axis, wherein in tension said at least one second suspension cable resists a second side load imposed on said boom which is opposed to said first side load.

6. The mining shovel as in any one of claims 1 to 4, including at least one second suspension cable having one end attached to said boom proximal said boom distal end and an opposing end attached to said support member, said at least one second suspension cable defining an angle relative to said boom longitudinal axis, 10 wherein lines defined by said first and second suspension cable intersect within the S. perimeter of said boom. eoeoo

7. A boom suspension assembly for supporting a distal end of a boom, S said assembly comprising: °°oo° S 15 a boom point box having a longitudinal axis, said longitudinal axis being parallel to a longitudinal axis of the boom when said boom point box is fixed to the distal end of the boom; and a first lug fixed to said boom point box, and defining an angle greater than 0 degrees relative to said boom point box longitudinal axis.

8. The boom suspension assembly as in claim 7, in which at least one suspension cable is attached to said first lug and extending toward a first attachment point at an angle substantially aligned with said lug.

9. The boom suspension assembly as in claim 7 or claim 8, including a /%,Nond lug fixed to said boom point box, and defining an angle greater than 0 degrees relative to said boom point box longitudinal axis, wherein said second lug is not parallel to said first lug.

The boom suspension assembly as in claim 9, in which at least one suspension cable is attached to said second lug and extending toward an attachment point at an angle substantially aligned with said second lug.

11. The boom suspension assembly as in claim 10, in which said suspension cable attached to said first lug defines a first line and said suspension cable 10 attached to said second lug defines a second line, wherein said first and second lines intersect within the perimeter of said boom point box.

12. The boom suspension assembly as in any one of claims 7 to 11, in which said first lug defines an angle greater than 5 degrees relative to said boom point box longitudinal axis. ooo.

13. A mining shovel substantially as herein described in the detailed description of the preferred embodiment with reference to the drawings.

14. A boom suspension assembly for supporting a distal end of a boom substantially as herein described in the detailed description of the preferred embodiment with reference to the drawings. DATED THIS FIFTH DAY OF NOVEMBER 2001. Bucyrus International, Inc. MARK ATTORNEYS