AU2011310234A1

AU2011310234A1 - Bucket Wheel Apparatus

Info

Publication number: AU2011310234A1
Application number: AU2011310234A
Authority: AU
Inventors: Takeshi Kamono; Takashi Nakano
Original assignee: Kawasaki Heavy Industries Ltd; Kawasaki Jukogyo KK
Current assignee: Kawasaki Motors Ltd
Priority date: 2010-09-29
Filing date: 2011-09-29
Publication date: 2013-03-21
Anticipated expiration: 2031-09-29
Also published as: KR20130069779A; CN103097613B; JP2012072623A; JP5763902B2; WO2012042885A1; KR101485276B1; CN103097613A; AU2011310234B2

Abstract

The objective of the present invention is to provide a bucket-wheel device that can be easily overhauled, can be produced in a short period of time, and can be supplied at a low cost. In the bucket-wheel device (A), a bucket (3c) is disposed at the ends of a plurality of arms (3b) disposed radially from a rotating shaft (3a), the rotating shaft (3a) is driven by a motor (2) through a reduction gear (1), and the bucket-wheel device is used as a payout device for devices such as a reclaimer (50). One end of the rotating shaft (3a) on the reverse side from the reduction gear is rotatably borne in a cantilevered manner at a frame, the other end of the rotating shaft (3a) is coupled to the output shaft (1b) of the reduction gear (1) through a coupling device (4), and the output shaft (2a) of the motor (2) is coupled to the input shaft (1a) of the reduction gear (1).

Description

Description Title of Invention: Bucket Wheel Apparatus Technical Filed [0001] The present invention relates to a bucket wheel apparatus for use as a discharging apparatus (a shoveling apparatus) of a "reclaimer", a "stacker-reclaimer", an "unloader" or the like, for the purpose of discharging a so-called "loose bulk material", such as coal and iron ore, from a stockyard, a vessel hold or the like. Background of Invention [0002] Heretofore, reclaimers and stacker-reclaimers have been used at the time of discharge of a loose bulk material in a stockpile from a stockyard for transfer to a designated area. On the other hand, unloaders have been used at the time of discharge of a bulk material loaded in a vessel from a vessel hold for transfer to a stockyard or other like destination. [0003] Such conventional reclaimers, stacker-reclaimers and unloaders are constructed such that there is installed, at the extremity of a boom, a "bucket wheel apparatus" as a " discharging apparatus" operative to shovel out a bulk material from a stockpile. In a bucket wheel apparatus of such a type, it is arranged that power is transmitted from a prime mover, such as an electric motor and an oil hydraulic prime mover, to the rotary shaft of a bucket wheel main body through a speed reduction device, whereby the bucket wheel main body rotates on its rotary shaft. [0004] The bucket wheel apparatus has originally been constructed at the extremity of the boom of the stacker-reclaimer as follows. Power is transmitted from the output shaft of the prime mover to the input shaft of the speed reduction device disposed so as to orient in the longitudinal direction of the boom. And, in the inside of the speed reduction device, the direction of the rotational axis is changed at a right angle through a bevel gear unit and, with establishment of a desired gear ratio through speed reduction gear pairs arranged in a plurality of stages, power is transmitted from the output shaft of the speed reduction device disposed so as to orient in a direction orthogonal to the longitudinal direction of the boom, through a coupling device, to the rotary shaft which pivotally supports the bucket wheel main body (see Patent Literature Publication 1). [0005] This results in increase in widthwise dimension of the extremity of the boom, due to which the extremity of the boom increases in weight. For this reason, it is inevitable that the weight of the counterbalance weight of the stacker-reclaimer has to be increased.

[0006] As shown in FIG. 7 and FIG. 8, in the light of the above-described situation, there has recently been employed the use of a speed reduction device 101 with a planet gear speed reduction mechanism as a speed reduction device 101 of a bucket wheel apparatus 1 00A . The bucket wheel apparatus 100A is of such a type that: a cylindrical outer circumferential wall 101a of the speed reduction device 101 itself operates as an output shaft; this output shaft serves also as a rotary shaft 103a of a bucket wheel main body 103; the cylindrical outer circumferential wall 101a is provided with a plurality of arms 103b that are arranged in a radial pattern; and each arm 103b is provided, at its distal end, with a bucket 103c. In addition, the rotary shaft 103a is also supported, at its end on the side opposite to the speed reduction device 101, against a frame 151 f by a bearing 103B and as a result, the rotary shaft 103a is supported in a so-called dual support fashion by the speed reduction device 101 and the bearing 103B when in or out of operation. In FIG. 7 and FIG. 8, the reference numeral 151 represents a boom of a reclaimer 150, the reference numeral 159 represents an operator's passageway used for the purpose of inspection et cetera and the reference numeral 102 in FIG. 7 represents an electric motor for driving the speed reduction device 101. Citation List Patent Literature [0007] Patent Literature Publication 1: JP-A-S56-135637 Summary of Invention Technical Problem [0008] However, the problem with the aforesaid conventional bucket wheel apparatus is that, due to that the cylindrical outer circumference wall 101a of the speed reduction devicel0l serves as the rotary shaft 103a of the bucket wheel main body 103 and in addition due to that the rotary shaft 103a is supported in a dual support fashion, it is required that the entire bucket wheel apparatus 1OOA be removed from the stacker-reclaimer or the unloader when conducting periodic overhauls of the speed reduction device 101. However, the entire bucket wheel apparatus 100A has a weight in excess of from about 6 tons (58.8 kN) to about 10 tons (98 kN), because of which the overhaul of the speed reduction device 101 is an extensive job that requires many hours and a great number of steps. [0009] In addition to the above, the output shaft of the speed reduction device 101 is configured so as to serve as the rotary shaft 103a of the bucket wheel main body 103. Therefore, it has been practiced in the past to design and manufacture the speed reduction device 101 on a case-by-case basis in conformity to the discharging capacity of the bucket wheel apparatus 1OA. Consequently, many of the parts used in the speed reduction device 101 such as a bearing et cetera are those that are specially made to order and the produce of the speed reduction device not only takes long periods of time and but also costs a lot of money. [0010] Bearing the above-described situation in mind, the present invention was devised. Accordingly, an object of the present invention is to provide a bucket wheel apparatus with a speed reduction device capable of being easily overhauled and capable of not only being manufactured in a much shorter period of time but also being supplied inexpensively. Solution to Problem [0011] A bucket wheel apparatus according to the present invention is an bucket wheel apparatus for use as a discharging apparatus in a machine such as a reclaimer, stacker reclaimer and an unloader, the apparatus including: a bucket wheel main body having a rotary shaft driven by a prime mover through a speed reduction device; a plurality of arms arranged radially from the rotary shaft; and a bucket for shoveling a bulk material disposed at a distal end of each of the arms. And the apparatus is characterized in that: the rotary shaft is rotatably supported, at its one end on the side opposite to the speed reduction device and in a cantilever fashion, against a frame whereas at its other end, the rotary shaft is coupled to an output shaft of the speed reduction device and an output shaft of the prime mover is coupled to an input shaft of the speed reduction device. [0012] According to the bucket wheel apparatus constructed as described above, by releasing the rotary shaft of the bucket wheel main body and the output shaft of the speed reduction device from being coupled with each other, the speed reduction device can be removed with ease without having to remove the bucket wheel main body. More specifically, one end of the rotary shaft of the bucket wheel main body on the side opposite to the speed reduction device is supported in a cantilever-like manner against the frame. Therefore, at the time of the overhaul of the speed reduction device, the speed reduction device can be removed just by releasing the coupling of the rotary shaft of the bucket wheel main body and the output shaft of the speed reduction device with the bucket wheel main body remaining installed in the frame. Therefore, it becomes possible that the speed reduction device can be overhauled with ease and in a short period of time. In addition, if as described above, the diameter of the rotary shaft of the bucket wheel main body is conveniently modified in conformity to the -r discharging capability of the bucket wheel apparatus, this then resolves the problem with regard to the degree of strength, whereby it becomes possible to employ, as the speed reduction device, commercially available products. [0013] It may be arranged that: in the aforesaid bucket wheel apparatus, the input shaft of the speed reduction device is disposed such that it is oriented in a direction at a right angle to the output shaft of the speed reduction device and the output shaft of the speed reduction device is disposed such that it is oriented in a direction orthogonal to the longitudinal direction of the boom. This arrangement is preferable in terms of being able to dispose the bucket wheel apparatus without increasing the widthwise dimension of the boom, by employing such a configuration that the speed reduction device is decreased in its widthwise dimension but increased in its lengthwise dimension, that is to say, the speed reduction gear train is arranged adjacently in the lengthwise direction of the output shaft. [0014] It may be arranged that in the aforesaid bucket wheel apparatus, the other end of the rotary shaft of the bucket wheel main body is coupled through a coupling device to the output shaft of the speed reduction device. This arrangement is further preferable in terms of being capable of easily releasing the rotary shaft of the bucket wheel main body and the output shaft of the speed reduction device from being coupled with each other by effecting release at the coupling device section. [0015] It may be arranged that in the aforesaid bucket wheel apparatus, the coupling device is in the form of a shrink disc. This arrangement makes it possible that the dimension of the coupling device in the axial longitudinal direction of the rotary shaft can be made as short as possible, whereby the width dimension of the extremity of the boom of the reclaimer, the stacker-reclaimer or the unloader et cetera can be made smaller to a further extent. As a result, it becomes possible to reduce the weight of the counterbalance weight of the stacker-reclaimer or the like, whereby the total weight can be reduced. [0016] In addition, it may be arranged that: the input shaft of the speed reduction device is oriented in the longitudinal direction of a boom; there is disposed, in the inside of the speed reduction device, a speed reduction gear train comprising a plurality of stages of spur gears for accomplishing a desired speed reduction ratio; and there is disposed, at a location adjacent to the speed reduction gear train in the longitudinal direction of the boom, a bevel gear unit for changing a direction of a rotational axis, whereby the output shaft of the speed reduction device is disposed such as to orient in a direction at a right angle to the longitudinal direction of the boom. This arrangement makes it possible that the speed reduction device can be made to decrease in its widthwise dimension but to increase in its longitudinal dimension. Consequently, by making effective use of the fact that there is considerable dimensional room in the longitudinal direction of the boom in the reclaimer, the stacker-reclaimer, the unloader, et cetera, the bucket wheel apparatus can be installed without having to increase the widthwise dimension of the boom. [0017] Furthermore, it may be arranged that: the speed reduction device and the prime mover are arranged on a single supporting base such that the speed reduction device and the prime mover are removable together with the supporting base from the frame at the time of the overhaul of either the speed reduction device or the prime mover. This arrangement achieves a bucket wheel apparatus that enables easy removal and attachment thereof to the frame. Advantageous Effects of Invention [0018] According to the bucket wheel apparatus constructed as above, the speed reduction device can be overhauled with ease and can be not only manufactured in a much shorter period of time but also supplied inexpensively. Brief Description of Drawings [0019] In the drawing figures: FIG. 1 is an overall side view of a reclaimer which is equipped, at the extremity of a boom thereof, with a bucket wheel apparatus according to an embodiment of the present invention; FIG. 2 is an overall top plan view of the reclaimer shown in FIG. 1; FIG. 3 is an enlarged top plan view showing the bucket wheel apparatus shown in FIG. 1 and FIG. 2 mounted at the extremity of the boom, and the sections located adjacent thereto; FIG. 4 is a view on arrow of IV-IV of FIG. 3, with the section of the speed reduction device indicated by hatching; FIG. 5 is a partially cross-sectional enlarged view showing the main parts of FIG. 4 with the removal sections represented by thick line; FIG. 6 is a view on arrow of VI-VI of FIG. 3; FIG. 7 is a side view showing the main parts of a conventional bucket wheel apparatus; and FIG. 8 is a view on arrow of IIX-IIX of FIG. 7 showing the main parts of the conventional bucket wheel apparatus. Description of Embodiments [0020] Hereinafter, by making reference to the drawing figures and based on the embodiments, a detailed description will be given for a bucket wheel apparatus according to the present invention. (Embodiments) Referring to FIG. 1 and FIG. 2, there is shown a bucket wheel apparatus represented by letter A. As a shoveling device (a discharging apparatus) for use in a reclaimer 50 or other like device, the bucket wheel apparatus A is mounted at an extremity 51 e of a boom 51. The boom 51 is disposed such that it is rotatable and its extremity can be raised or lowered in a free manner. In FIG. 1 and FIG. 2, the reference numeral 53 represents a counterbalance weight; the reference numeral 54 represents a pivotal axis as the center of rotation of the boom 51; the reference numeral 55 represents an operator's cab; the reference numeral 56 of FIG. 1 represents a travelling apparatus which is disposed under the stacker-reclaimer 51 and which is operable to move (self-propel) in a direction orthogonal to the sheet of FIG. 1; the reference 57 of FIG. 2 represents travelling rails; the reference numeral 58 represents a belt conveyor for transporting loose bulk material discharged by the bucket wheel apparatus A to the base end of the boom 51; and the reference numeral 60 of FIG. 1 and FIG. 2 represents a belt conveyor for transporting the loose bulk material, which has been discharged by the reclaimer 50, to a designated location along the travelling direction. In addition, the reference numeral 59 in FIG. 3 and FIG. 4 represents an operator's passageway used for the purpose of inspection or other like purpose. [0021] For the case of the bucket wheel apparatus A, as illustrated in, for example, FIGS. 3 through 6, an electric motor 2 serving as a prime mover of the bucket wheel apparatus A and a speed reduction device 1 for reducing the rotating speed of the electric motor 2 are placed (arranged) on a supporting base 52 disposed on a frame 51 f at the extremity of the boom 51 (see FIG. 1 and FIG. 2). And, it is arranged that, as shown in FIG. 3 and FIG. 6, an output shaft 2a of the electric motor 2 and an input shaft la of the speed reduction device 1 are coupled together through a coupling device 11 (a gear coupling device in the present embodiment), and the speed reduction device 1 is driven by the electric motor 2. The present embodiment employs, as the electric motor 2, a speed variable electric motor of the variable voltage, variable frequency control (VVVF control) type whose rotating speed and rotating torque are freely controllable by a control device. However, as the electric motor 2, other general electric motors of the type other than the VVVF control type may be used. [0022] Furthermore, as shown in FIGS. 3 through 5, the output shaft lb of the speed reduction device 1 is coupled, through the coupling device 4 in the form of a so-called "shrink disc", to a rotary shaft 3a of the bucket wheel main body 3. More specifically, the output shaft lb of the speed reduction device 1 is inserted and fitted to a hollow portion, defined on the side of the speed reduction device 1, of the cylindrical rotary shaft 3a of the bucket wheel main body 3; both tapered surfaces are formed in the outer peripheral part of the rotary shaft 3a, the both tapered surfaces expanding in diameter in the middle, relative to the axial longitudinal direction, of the inserting/fitting portion but shrinking in diameter on both sides of the middle part; around both tapered surfaces of the rotary shaft 3a, there is disposed a shrink disc body which is provided, in its inner circumferential surface, with both tapered surfaces corresponding to the both tapered surfaces of the rotary shaft 3a, the shrink disc body being divided into two sections in the axial longitudinal direction; and these two divided sections of the shrink disc body are clamped together in the axial longitudinal direction with the aid of a plurality of bolts 4a (see FIG. 5) such that they are positioned adjacent to each other. And, when clamped by the bolts 4a (see FIG. 5), the rotary shaft 3a is pushed inwardly in the radial direction (towards the output shaft 1b), as a result of which the rotary shaft 3a and the output shaft lb are frictionally pressed against each other whereby the output shaft lb and the rotary shaft 3a are coupled together. Consequently, rotational motion is transferred from the output shaft lb to the rotary shaft 3a. As the coupling device 4, the aforesaid configuration provided with tapered surfaces should not be considered limitative. In addition, the output shaft lb and the rotary shaft 3a may indirectly be coupled together through the coupling device 4 as described above, but alternatively could directly be coupled together in some cases. In consequence, it is configured that the rotary shaft 3a is rotated by the electric motor 2 through the speed reduction device 1. And, by using the coupling device 4 in the form of a "shrink disc" as described above, the dimensions of the coupling device 4 in the axial longitudinal direction of the rotary shafts lb and 3a become extremely short. [0023] As shown in FIG. 3 and FIG. 4, in the bucket wheel main body 3 of the bucket wheel apparatus A, a plurality of arms 3b are disposed such that when viewed sideways, they extend in a radial pattern (see the bucket wheel main body 3 in FIG. 1) from the outer circumferential surface of the rotary shaft 3a (see FIG. 1), and the distal end (the outer diameter end) of each V arm 3b is provided with a bucket 3c for shoveling a loose bulk material (for example, coal, iron ore). And, as shown in FIG. 3 and FIG. 4, the rotary shaft 3a is rotatably supported, through bearings 12, against the frame 5 If of the boom 51. That is to say, for the case of the bucket wheel apparatus A according to the present embodiment, the rotary shaft 3a is supported in a cantilever fashion by a support shaft 13 (described hereinafter) supported against the frame 15f through the bearings 12 when out of operation. More specifically, according to the present embodiment, the area of the rotary shaft 3a on the side opposite to the speed reduction device 1 is formed into a cylindrical shape having therein a cylindrical cavity, and arranged coaxially with the rotary shaft 3a in the cylindrical cavity within the rotary shaft 3a is a cylindrical support shaft 13. And, the end of the support shaft 13 on the side opposite to the speed reduction device is fixed to the frame 51f. And, as shown in FIG. 5, by arrangement of the bearings 12 made up of automatic alignment roller bearings between the support shaft 13 and the rotary shaft 3a, the rotary shaft 3a is rotatably supported against the support shaft 13. [0024] In addition, as shown in FIG. 3 and FIG. 6, it is arranged that the input shaft 1 a of the speed reduction device 1 is disposed so as to orient in the longitudinal direction of the boom 51, and through this input shaft la, the rotating speed of the output shaft 2a of the electric motor 2 is reduced to a desired value by a gear train (a speed reduction gear train) composed of internally disposed spur gears of the three-stage type (not shown). In addition, for the case of the speed reduction device 1, it is configured that the direction of the rotational axis is changed by 90 degrees, i.e., at a right angle, for transmission of the rotary motion from the gear train to the output shaft lb via a pair of bevel gear units. In the present embodiment, the pair of the bevel gear units is disposed adjacent, in the longitudinal direction of the boom 51, to the gear train composed of spur gears of the three-stage type. Consequently, for the case of the present embodiment, it is arranged that, with respect to the rotation speed of the output shaft 2a of the electric motor 2, there is made a speed reduction to a desired level, for example, to 1/160, and the rotational axis direction is internally changed by 90 degrees. As a result of this, the speed reduction device 1 is implemented such that its widthwise dimension becomes smaller whereas its longitudinal dimension becomes longer. [0025] In addition, as a different embodiment of the present invention, it may be arranged that the aforesaid pair of the bevel gear units is disposed on the side of the input shaft 1 a within the speed reduction device 1 while the aforesaid gear row composed of spur gears of the three-stage type is disposed on the side of the output shaft lb within the speed reduction device 1. In other words, even if the bevel gear units are disposed upstream of the flow of power transmission whereas the gear train composed of spur gears of the three-stage type is disposed downstream of the flow of power transmission, the same operation/working effects as described above can be accomplished. [0026] As shown in FIG. 6, the supporting base 52 is fixed to the frame 51f through a plurality of detachable coupling pins 34 or attachment bolts (not shown). Therefore, it is arranged that the electric motor 2 and the speed reduction device 1 both installed on the frame 51 f can be removed therefrom together with the supporting base 52 by removing the plural (for example, two to four) coupling pins 34 or the attachment bolts (not shown). In addition, at the time when removing, from on the frame 51f, the electric motor 2 and the speed reduction device 1 both placed on the frame 51 f together with the supporting base 52, clamp bolts 4a of the coupling device 4 (see FIG. 5) are loosened to thereby release the rotary shaft 3a from being coupled to the output shaft lb of the speed reduction device 1. In addition, at the time of such a removal operation, a cover 9, shown in FIG. 4 and FIG. 5, for covering the coupling device 4 is at least removed. [0027] For the case of the bucket wheel apparatus A according to the present invention, since it is configured as described above, the bucket wheel main body 3 including the rotary shaft 3a is allowed to remain supported, in a cantilever fashion, against the frame 51 even after removal of the electric motor 2 and the speed reduction device 1 both placed on the frame 51 f from the frame 51 together with the supporting base 52. [0028] Consequently, at the time of the overhaul of the speed reduction device 1, as shown in FIG. 5, the supporting base 52 may be removed from the frame 51f of the boom 51 in the following manner: wire cables (not diagrammatically shown) are hitched to suspension hooks 35; and then the electric motor 2 and the speed reduction device 1 both placed on the supporting base 52 are hoisted together with the supporting base 52 by a crane or other like device. Therefore, the weight to be removed is less than approximately about half that of the conventionally constructed bucket wheel apparatus. Moreover, the requirement at the time of such a removal operation is just to effect release of the coupling device 4 and removal of the coupling pins 34 (see FIG. 6) or the attachment bolts. [0029] In addition, the weight of the speed reduction device 1 itself becomes considerably lighter owing to the structure free from the existence of heavy internally-toothed gears, when compared to conventional speed reduction devices employing a conventional planet gear mechanism, whereby it is made possible to achieve a further weight saving for the boom 51. Therefore, it becomes possible to reduce the weight of the counterbalance weight 53 (shown in FIG. 1 and FIG. 2) disposed opposite across the pivotal axis 54 of the boom 51 for providing a weight balance between the boom 51 and the bucket wheel apparatus A. More specifically, the counterbalance weight 53 requires a weight more than about three times the weight of the bucket wheel apparatus A because its distance to the pivotal axis 54 is shorter as compared to the bucket wheel apparatus A. Therefore, if the weight of the bucket wheel apparatus A is reduced, this considerably promotes the weight saving of the counterbalance weight 53. In this case, the own weight of the reclaimer 50 equipped with the bucket wheel apparatus A can be reduced significantly, as a result of which it is made possible to also reduce the drive force for self-propelling the reclaimer 50. [0030] In addition, from the standpoint of price, it becomes possible to make a considerable reduction in price because it is possible to employ, as the speed reduction device 1, a standard speed reduction device or a speed reduction device confirming to such a standard speed reduction device. [0031] Incidentally, as shown in FIG. 1 and FIG. 2, it is arranged that the boom 51 is provided with a belt conveyor 58 whose forward end is positioned in the vicinity of the bucket wheel apparatus A and which is disposed extendedly along the longitudinal direction of the boom 51, and the loose bulk material shoveled by the bucket wheel apparatus A is transferred by the belt conveyor 55 through a chute (not shown) either to a group of belt conveyors including another conveyor 60 et cetera disposed on the downstream side of the conveyor 55 or, depending on circumstances, to the belt conveyor of a tripper (not shown) which is coupled to the reclaimer 50. Then, the loose bulk material stored in a stockyard or other like enclosure is carried out to a designated location. [0032] Incidentally, in the foregoing embodiments, the description has been given in regard to such a case that the bucket wheel apparatus according to the present invention is used as a discharging apparatus for use in a reclaimer or a stacker-reclaimer. However, there is no need to say that the bucket wheel apparatus of the present invention can likewise be used for other machines such as an unloader et cetera with the same operation/working effects. [0033] There is no need to say that the present invention is in no way limited to the foregoing embodiments. Therefore, the present invention may be carried out in various manners within I I the scope based on the technical idea of the present invention. Industrial Applicability [0034] The bucket wheel apparatus according to the present invention can be utilized as a discharging apparatus for use in a machine such as a reclaimer, a stacker-reclaimer and an unloader. Reference Signs List [0035] A: bucket wheel apparatus 1: speed reduction device la: input shaft 1b: output shaft 2: electric motor (prime mover) 3: bucket wheel main body 3a: rotary shaft 3b: arm 3c: bucket 4: coupling device

Claims

1. A bucket wheel apparatus for use as a discharging apparatus in a machine such as a reclaimer, stacker-reclaimer and an unloader, the apparatus comprising: a bucket wheel main body having a rotary shaft driven by a prime mover through a speed reduction device; a plurality of arms arranged radially from the rotary shaft; and a bucket for shoveling a bulk material disposed at a distal end of each of the arms, wherein said rotary shaft is rotatably supported, at its one end on the side opposite to said speed reduction device and in a cantilever fashion, against a frame whereas at its other end, said rotary shaft is coupled to an output shaft of said speed reduction device and an outout shaft of said prime mover is coupled to an input shaft of said speed reduction device.

2. The bucket wheel apparatus as set forth in claim 1, wherein said input shaft of said speed reduction device is disposed such that it is oriented in a direction at a right angle to said output shaft of said speed reduction device.

3. The bucket wheel apparatus as set forth in claim 1, wherein said other end of said rotary shaft of said bucket wheel main body is coupled through a coupling device to said output shaft of said speed reduction device.

4. The bucket wheel apparatus as set forth in claim 3, wherein said coupling device is in the form of a shrink disc.

5. The bucket wheel apparatus as set forth in claim 1, wherein: said input shaft of said speed reduction device is oriented in the longitudinal direction of a boom; there is disposed, in the inside of said speed reduction device, a speed reduction gear train including a plurality of stages of spur gears for accomplishing a desired speed reduction ratio; and there is disposed, at a location adjacent to said speed reduction gear train in the longitudinal direction of said boom, a bevel gear unit for changing a direction of a rotational axis, whereby said output shaft of said speed reduction device is disposed such as to orient in a direction at a right angle to the longitudinal direction of said boom.

6. The bucket wheel apparatus as set forth in claim 2, wherein: said input shaft of said speed reduction device is oriented in the longitudinal direction of a boom; there is disposed, in the inside of said speed reduction device, a speed reduction gear train including a plurality of stages of spur gears for accomplishing a desired speed reduction ratio; and there is disposed, at a location adjacent to said speed reduction gear train in the longitudinal direction of said boom, a bevel gear unit for changing a direction of a rotational axis, whereby said output shaft of said speed reduction device is disposed such as to orient in a direction at a right angle to the longitudinal direction of said boom.

7. The bucket wheel apparatus as set forth in claim 1, wherein: said speed reduction device and said prime mover are arranged on a single supporting base such that said speed reduction device and said prime mover are removable together with said supporting base from said frame at the time of the overhaul of either said speed reduction device or said prime mover.

8. The bucket wheel apparatus as set forth in claim 2, wherein: said speed reduction device and said prime mover are arranged on a single supporting base such that said speed reduction device and said prime mover are removable together with said supporting base from said frame at the time of the overhaul of either said speed reduction device or said prime mover.

9. The bucket wheel apparatus as set forth in claim 5, wherein: said speed reduction device and said prime mover are arranged on a single supporting base such that said speed reduction device and said prime mover are removable together with said supporting base from said frame at the time of the overhaul of either said speed reduction device or said prime mover.

10. The bucket wheel apparatus as set forth in claim 6, wherein: said speed reduction device and said prime mover are arranged on a single supporting base such that said speed reduction device and said prime mover are removable together with said supporting base from said frame at the time of the overhaul of either said speed reduction device or said prime mover.