Rotary bucket assembly

Abstract

 A cylindrical bucket (6) for drilling a vertical hole in the earth is designed to be rockably mounted on a hydraulically driven working machine and has a fixed bucket member (21) which is partially opened at one side and at the bottom and a movable bucket member (26) which is pivotable about an axis (45) adjacent the opening of the fixed bucket member to open and close the opening. The fixed and movable bucket members have such cross-sectional shapes that, when the movable bucket member is in its closed position, the two members cooperate to form a substantially circular shape in cross-section.

Description

BACKGROUND OF THE INVENTION

Field of the Invention:

[0001] The present invention relates to a rotary bucket assembly used to make a vertical hole, which is rockably mounted on the forward end of an arm of a hydraulically driven working machine. More particularly, the present invention is concerned with a rotary bucket assembly used to dig a narrow and deep ditch and to remove the boulders and the earth remaining on the bottom of the ditch.

Description of the Related Art:

[0002] Rotary buckets for making vertical holes are also used to dig a narrow and deep ditches in which the pipes for accommodating electric wires or telephone lines, gas pipes or water supply and sewerage pipes are buried. Such a ditch is dug by making by a rotary bucket vertical holes in series at an adequate pitch. Fig. 15 shows a conventional rotary bucket called an earth drilling bucket. A bracket 8 is mounted on the forward end of an arm of a hydraulically driven working machine, such as a hydraulic shovel. A rotating device 10 which is an hydraulic motor for rotating the bucket 11 is mounted on a bracket 8. The rotary bucket 11 is cylindrical and mounted on the lower portion of the rotating device 10 with a bearing 9 therebetween. A bottom lid 12 is provided at an opening in the bottom of the rotary bucket 11 in such a manner that the lid can pivot about a pin 13 to open and close the rotary bucket 11. The rotary bucket 11 is provided with a claw 61 for locking the bottom lid 12 and with a manually operated trip lever 14 by which the claw 61 is turned to open the bottom lid 12 by its own weight.

[0003] Japanese Patent Examined Publication No. 45-5231 discloses another rotary bucket which is separated into two parts in the longitudinal direction of the bucket. In this rotary bucket, links are provided at the upper portions of the two bucket parts and crossed to form an X-shape. The thus crossed portions of the links are pivotably coupled with each other by a shaft. A roller is mounted on the upper end of each of the links. The shaft is connected to the lower end of a kelly-bar. The two-part bucket is opened by lifting the kelly-bar and thereby pressing the rollers against a thrust plate provided at the under surface of a kelly-bar driving device. This two-part bucket also has a mechanism for keeping the bucket closed and another mechanism for locking and releasing this mechanism in response to the opening and closing of the bucket.

[0004] The conventional rotary bucket shown in Fig. 15 is of the structure that the earth in the bucket 11 is discharged from the bucket by opening the bottom lid 12. Thus, a space shown by a dimension H in Fig. 15, which is measured from the bottom surface of the bucket 11 to the lower end of the bottom lid 12 when it is opened, is required for discharging the earth, with a result that an associated hydraulically driven working machine must be operated such that it assures the dimension H each time it is moved in the vertical direction to discharge the earth from the rotary bucket. This means that the height of banking is decreased accordingly. Furthermore, in a case where the length of the bucket 11 is increased so as to increase the capacity thereof, the amount of the earth attaching to the inner surface of the bucket 11 increases accordingly, although it depends on the quality of the earth, with resultant decreases in the earth discharge ability and in the working efficiency. Furthermore, when the bottom lid 12 is to be closed, it has to be locked in a state where the bucket 11 is pressed against the earth. This locking operation and the opening operation of the bottom lid 12 have to be manually conducted each time the bottom lid 12 is opened and closed, thus degrading the operability of the bucket.

[0005] The two-part bucket discussed above is a special bucket solely for use with the kelly-bar, so that it cannot be mounted directly on the working machine. Furthermore, it requires a highly rigid opening/closing mechanism. Moreover, since the bucket is opened at a fixed angle, clayey earth cannot be discharged from it smoothly.

[0006] Although the afore-mentioned conventional buckets may be used to level the bottom of ditches, they cannot be used for gripping the boulders and the earth remaining on the bottom of the ditches to clean out the ditches. These operations must therefore be manually performed or conducted using other attachments, lowering the efficiency of a ditch-digging operation.

SUMMARY OF THE INVENTION

[0007] In view of the above-described problems of the prior art, an object of the present invention is to provide a rotary bucket which is capable of digging a narrow, deep ditch efficiently and with a high degree of earth discharge ability and a high operability, which is capable of readily removing the boulders and the earth remaining on the bottom of the ditch.

[0008] The rotary bucket assembly according to the present invention includes a generally cylindrical bucket, a bracket through which the bucket is mounted on a hydraulically driven working machine, a hydraulic motor on the bracket for rotating the bucket, and a bearing disposed between the bracket and the bucket, the bucket including a top portion connected to the bearing and a bottom wall provided with a plurality of cutters for cutting earth and taking the thus cut earth into the bucket during rotation thereof, characterized in that bucket comprises a fixed bucket member which is partially opened at one side and at the bottom thereof, a movable bucket member which is pivotable about an axis disposed adjacent the opening of said the bucket member to open and close the opening, and pivoting means provided on the fixed bucket member to pivotally move movable bucket member over an arbitrary angle.

[0009] In a first embodiment of the present invention, the said axis is located adjacent the upper portion of the bucket. In a second embodiment of the invention, however, the axis is located adjacent the bottom portion of the bucket.

[0010] In the first embodiment of the invention, a pair of plates are preferably provided on the inner surface of the fixed bucket member along two side edges of the opening of the fixed bucket member such that the distance between the two plates increases towards the opening to facilitate an easy discharge of earth from the bucket. In the first embodiment of the invention, moreover, edge members are preferably provided along side edges of the opening of one of the fixed and movable bucket members, while recessed members are preferably provided along side edges of the opening of the other of the fixed and movable bucket members such that each of the edge members is engaged with an associated recessed member during excavation to advantageously assure that torque of rotation of the backet is smoothly transmitted to both of the fixed and movable bucket members.

[0011] In the second embodiment of the invention, the movable bucket member is opened and closed preferably by a link mechanism which is operative to keep the movable bucket member open when it is opened. The link mechanism is foldable within the fixed bucket member when the movable bucket member is closed. In the second embodiment of the invention, moreover, the movable bucket member preferably includes a portion having a generally U-shaped cross-section the bottom of which is substantially flat.

[0012] When a vertical hole is to be made in the ground using the rotary bucket according to the present inven­tion, the bucket is rotated in a state where the movable bucket member is kept closed. During the rotation, earth is cut out by a plurality of cutters mounted on the bottom surface of the bucket and is taken into the bucket. The earth in the bucket is discharged by moving the bucket over, for example, a dump truck at a predetermined height and then rocking the bucket so that the movable bucket member is positioned slantingly or parallel to the floor, depending on the quality of the earth, and at the same time, opening the movable bucket member. Since the bucket is opened at one side and positioned slantingly or parallel to the floor when the earth is discharged the distance of the vertical movement of an associated hydraulic working machine can be reduced and the height of the banking can be increased.

[0013] The rotary bucket assembly according to the present invention can also be used to dig a ditch by repeating the vertical hole drilling operations in sequence at an adequate pitch. The rotary bucket assembly in which the pivot axis of the movable bucket member is provided adjacent the upper portion of the bucket can be used to grip boulders scattering on the bottom of the ditch by opening and closing the movable bucket member. Furthermore, earth deposited in the ditch can be removed to clean out the ditch by moving the bucket along the ditch by the hydraulically working machine and keeping the movable bucket member opened. The resistance to the discharge of the earth can be reduced and the earth can therefore be smoothly discharged from the bucket by the pair of plates provided along the two side edges of the inner surface of the fixed bucket member. The edge and recessed members provided along the side edges of the openings of the fixed and movable bucket members are engaged with each other during the rotation of the bucket, so that the torque of rotation can be uniformly transmitted to both of the fixed and movable bucket members.

[0014] The rotary bucket assembly in which the pivot axis of the movable bucket member is provided adjacent the bottom portion of the bucket can also be used to remove earth deposited on the bottom of a ditch to clean out the same. The bucket assembly can also be used to scoop out earth deposited in the ditch by moving the bucket along the ditch in a state where the movable bucket member is kept open. The efficiency of the earth scooping operation is improved by the substantially flat bottom of the generally U-shaped cross-section of the portion of the movable bucket member which bottom makes contact with the bottom of the ditch.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] 

Fig. 1 is a longitudinal cross-sectional view of a first embodiment of a rotary bucket of the present invention;

Fig. 2 is a bottom view of the rotary bucket shown in Fig. 1;

Fig. 3 is a side elevational view of the rotary bucket taken in the direction shown by line III - III in Fig. 1;

Fig. 4 is a cross-section taken along line IV - IV in Fig. 3;

Fig. 5 is a cross-section taken along line V - V in Fig. 1;

Fig. 6 is an enlarged fragmentary side view of the bucket taken along line VI - VI in Fig. 5;

Figs. 7, 8 and 9 illustrate examples of the operations of a hydraulic shovel on which the rotary bucket shown in Fig. 1 is mounted;

Fig. 10 is a longitudinal sectional view of a second embodiment of a rotary bucket of the present invention;

Fig. 11 is a bottom view of the rotary bucket shown in Fig. 10;

Fig. 12 is a cross-section taken along line XII - XII in Fig. 10;

Fig. 13 is a cross-section taken along line XIII - XIII in Fig. 10;

Fig. 14 illustrates an example of the operation of a wheel type hydraulic shovel on which the rotary bucket shown in Fig. 10 is mounted; and

Fig. 15 shows an example of the conventional rotary bucket.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] A first embodiment of the present invention will be described below with reference to Figs. 1 to 9.

[0017] A hydraulically driven working machine on which a rotary bucket 6 according to the present invention is mounted is shown in Fig. 7 and comprises a hydraulic shovel body 1 including a lower traveller 1a, a swivel device 1b, a boom 2, a boom cylinder 3 for derricking the boom 2, an arm 4, an arm cylinder 5 for derricking the arm 4, a bucket cylinder 7 for derricking the bucket 6, and a rotation angle increasing link 38.

[0018] The bucket 6 is rockably mounted on the arm 4 of the hydraulic shovel through a bracket 15 which has pin holes 16a and 16b to which the forward ends of the arm 4 of the hydraulic shovel shown in Figs. 7 and 8 and the rotation angle increasing link 38 are respectively coupled by pins 39 and 40. The rotation angle increasing link 38 is connected at its rearward end to the bucket cylinder 7 by a pin. A hydraulic motor 17 for rotating the bucket 6 is mounted on the bracket 15. To the under surface of the bracket 15 is fixed an outer race 41 of a bearing 19 by means of bolts 20. An internally toothed gear 43 provided on an inner race 42 of the bearing 19 engages with a pinion 18 fixed to an output shaft of the hydraulic motor 17.

[0019] A top plate 44 of a fixed member 21 of the bucket 6 is mounted on the under surface of the inner race 42 by means of bolts 22. The fixed bucket member 21 is opened at one side thereof from its top to its bottom. A movable member 26 of the bucket 6 is fitted to the opening of the fixed bucket member 21. Both the fixed and movable bucket members 21 and 26 have arcuate cross-sections, as shown in Fig. 4. In this embodiment, the circumference of the fixed member 21 is slightly longer than that of a semicircle, while the circumference of the movable member 26 is slightly shorter than that of a semicircle.

[0020] The movable bucket member 26 is fitted to the opening such manner that it can pivot about and axis of a hydraulic pivoting means 29 mounted on the upper portion of the fixed bucket member 21 by means of bolts 30. More specifically, lugs 32 are fixed to an output shaft 45 of the pivoting means 29 by means of keys 31, and the movable bucket member 26 is mounted on the lugs 32 by means of bolts 33. The pivoting means 29 is of the known and arranged such that the output shaft 45 is rotated in one direction when hydraulic oil is supplied into one of the oil supply ports and in the opposite direction when the oil is supplied into the other oil supply port. A hydraulic oil supply circuit for the pivoting means 29 includes a rotary joint 35 mounted on a boss 36 fixed at the center of the rotation of the ceiling plate 44 of the fixed bucket member 21 shown in Fig. 1, a hydraulic pipe connection port 34 provided in the bracket 15 for intro­ducing the oil coming from the hydraulic shovel body 1 shown in Figs. 7 and 8 to the rotary joint 35, and a pipe (not shown) for connecting the rotary joint 35 to the pivoting means 29.

[0021] As shown in Figs. 4 and 5, a pair of plates 37 are fixed to the inner surface of the fixed bucket member 21 in such a manner that the distance between them increases towards the opening of the bucket member 21. The pair of plates 37 have the function of reducing the force of attachment of the earth to facilitate easy discharge of the earth from the bucket 6 as well as of reinforcing the fixed bucket member 21. Edges 28 made of a steel plate are fixed to the fitting portions of one of the fixed and movable bucket members 21 and 26 (to the movable bucket member 26 in this embodiment), while recessed members 27 made of steel plate are fixed to the fitting portions of the other (the fixed bucket member 21 in this embodiment). The edges 28 are engaged with the recessed members 27 when the movable bucket member 26 is closed. The fixed bucket member 21 has a bottom plate 46, as shown in Figs. 1 and 2. To the under surface of the bottom plate 46 are fixed a plurality of bottom cutters 24 for cutting into the earth while the bucket 6 is rotating and for taking the earth thus cut into the bucket 6. Side cutters 25 are mounted on the lower side portions of the fixed bucket member 21. The earth cut by the bottom cutters 24 and the side cutters 25 is taken into the bucket 6 through an inlet 23 provided in the bottom plate 46 and the lower side surfaces of the fixed bucket member 21. A lid plate with a spring may be provided for the earth inlet 23. Furthermore, the side cutters 25 and the earth inlet 23 may be also provided for the upper portion of the fixed bucket member 21.

[0022] Next, the operation of the rotary bucket 6 will be described below. A vertical hole drilling is performed in a state where the movable bucket member 26 is closed, as shown by the solid line in Fig. 1, and in the manner described hereinunder. First, the positioning of the bucket 6 at a site where a hole is to be made and the control and adjustment posture thereof are effected by a combination of the operations, including the travel of the hydraulic shovel body 1 which is achieved by the operation of the lower traveller 1a, the slewing of the hydraulic shovel body 1 achieved by the operation of the swivel device 1b, the derricking of the boom 2 which is achieved by the operation of the boom cylinder 3, the derricking of the arm 4 which is accomplished by the operation of the arm cylinder 5, and the derricking of the bucket 6 which is accomplished by the operation of the bucket cylinder 7. After the positioning and the posture control of the bucket 6 have been finished, the bucket 6 is lowered while it is rotated to start an excavation. The bucket 6 is rotated by the hydraulic motor 17 whose rotational force is transmitted to the internally toothed gear 43 on the inner race 42 from the pinion 18. As the bucket 6 rotates, the earth cut away by the bottom cutters 24 and the side cutters 25 enters the bucket through the inlet 6. At the time since the movable bucket member 26 is closed by the pivoting means 29, no earth leaves the bucket 6. The torque which acts on the fixed and movable bucket members 21 and 26 during the excavation is transmitted to them smoothly as if they were formed as one unit. This is because the edges 28 engage with the recessed members 27 provided at the fitting portions of the bucket members to minimize the torsional deformation of the bucket 6, which would otherwise occur during the excavation.

[0023] When the earth in the bucket 6 is to be discharged, the bucket 6 is first moved over, for example, a dump truck 70 at a predetermined height h by the operations of the swivel device 1b, the boom cylinder 3 and the arm cylinder 5. Next, the bucket 6 is rocked by the operation of the bucket cylinder 7 so that the movable bucket member 26 is directed downwards or obliquely downwards depending on the quality of the earth, and the movable bucket member 26 is opened concurrently with this rocking of the bucket 6 by rotating the output shaft 45 of the pivoting means 29 by the supply of the pressure oil from the hydraulic pressure source of the hydraulic shovel body 1 to the pivoting means 29 through the hydraulic pipe connecting part 34, the rotary joint 35, and the boss 36. The movable bucket member 26 can be angularly moved through an arbitrary angle to the position shown by the broken line in Fig. 1. Since the movable bucket member 26 can be opened when the opening of the bucket 6 is directed slantingly or downwards, earth of any quality can be discharged from the bucket smoothly with the aid of the plates 37. At that time, the earth discharge height h shown in Fig. 7 can be reduced as compared with a conventional bucket of the type which is opened by opening the bottom plate thereof. Thus, the distance through which the hydraulic shovel is moved vertically during the discharge of the earth can be reduced, thereby improving the operation efficiency. This means that the height of the banking can be increased.

[0024] After the discharge of the earth, the movable bucket member 26 is closed by supplying the pressure oil to the pivoting means 29 in a manner opposite to that in which the oil is supplied for the purpose of opening the movable bucket member 26.

[0025] A narrow and deep ditch is dug by repeating the vertical hole drilling operation in sequence at an adequate pitch. On the bottom of the ditch are scattered boulders 47 and the earth tumbled down from the periphery of the ditch. Fig. 8 shows the operation of gripping the boulders 47 remaining on the bottom of the ditch. During this operation, the bucket 6 is hydraulically locked so that it is not rotated, and the movable bucket member 26 is opened and closed to grip and release the boulders 47. Fig. 9 shows the operation of removing the earth deposited on the bottom of a ditch 48 to clean out the ditch. During this operation, the bucket 6 is hydraulically locked so that it is not rotated by any external force, and the movable bucket member 26 is hydraulically locked in the state where it is opened. The fixed bucket member 21 is moved in an arbitrary direction indicated by the arrow c by a composite operation of the slewing of the hydraulic shovel body 1 in the direction indicated by an arrow a and the movement of the arm 4 in the direction indicated by an arrow b, like the conventional digging bucket which is attached to the hydraulic shovel, so as to clean out the ditch. The orientation of the bucket 6 may be shifted from that of the ditch 48 by slewing the hydraulic shovel body 1. However, it may be corrected by gradually rotating the bucket 6.

[0026] A second embodiment of the present invention will now be described below with reference to Figs. 10 to 14 in which the same reference numerals are used to denote the parts which are the same as those shown in Figs. 1 to 9.

[0027] The rotary bucket of this embodiment is mounted on a wheel type hydraulic shovel which includes a shovel body 1′, a traveller 1′a, and a swivel device 1′b, as shown in Fig. 14.

[0028] A generally cylindrical bucket 50 consists of a fixed bucket member 51 and a movable bucket member 52. The ceiling plate 44 of the fixed bucket member 51 is fixed to the under surface of the inner race 42 of the bearing 19 by means of the bolts 22. The fixed bucket member 51 is opened at one side thereof from a point near to its top, to its bottom, while the movable 52 is fitted to that opening. The fixed bucket member 51 has a bottom plate 53 which is pivotally connected to a bottom plate 52a of the movable 52 by a hinge 54 having a hinge a pin 55. On the bottom of the bottom plate 53 are mounted a plurality of bottom cutters 24, as in the case of the first embodiment.

[0029] The portion of the movable bucket member 52 located in the vicinity of the bottom plate 53 has an arcuate cross-section, as shown in Figs. 11 and 12, which, together with that of the fixed bucket member 51, forms a circle. However, the upper portion of the movable bucket member 52 has a U-shaped cross-section, as shown in Fig. 13. The flat bottom of this U-shaped portion can make a contact with the bottom of a ditch when the movable drum 52 is opened.

[0030] A hydraulic cylinder 56 for opening and closing the movable bucket member 52 is mounted on the upper portion of the fixed bucket member 51. A link 57 is provided on the inner surface of each of the side of the fixed bucket member 51. The upper end of each of the links 57 is pivotally coupled to a rod 56a of the hydraulic cylinder 56 by a pin. The upper portion of each of the links 57 is pivoted to the fixed drum 51 through a pin 58 fixed to the fixed bucket member 51. One end of a link 59 is pivotally coupled to the lower end of each of the links 57 by means of a pin. The other end of the link 59 is pivotally coupled to the substantially midpoint of the movable bucket member 52 by a pin. A stopper 59a is fixed to each of the links 59. When the movable bucket member 52 is opened by the operation of the hydraulic cylinder 56 and the links 57 and the links 59 are thereby aligned with each other, as shown by the dot-dashed line in Fig. 10, the stopper 59a comes into contact with a corresponding engaging portion 57a so as to keep the links in the stretched position. The hydraulic cylinder 56, the links 57 and the links 59 in combination form a pivoting means for pivotally moving the movable bucket member 52. The hydraulic oil supply circuit for the hydraulic cylinder 56 is the same as that employed in the first embodiment.

[0031] Next, the operation of the second embodiment will be described. A vertical hole drilling with the bucket 50 is performed in a state where the links 57 and 59 are folded within the fixed bucket member 51 by the elongation of the hydraulic cylinder 56 to close the movable bucket member 52, as shown by the solid line in Fig. 10, as in the case of the first embodiment. First, the positioning and the posture control of the bucket 50 are performed by a combination of the travelling and the slewing of the hydraulic shovel body, the derricking of the boom, the derricking of the arm, and the derricking of the bucket 50. Next, the bucket 50 is lowered while being rotated to start an excavation. In that case, rotation of the bucket 50 by the hydraulic motor 17, cutting of the earth by the bottom cutters 24 and the side cutters 25 and the taking in of the cut earth into the bucket 50 are performed in the same manner as that of the first embodiment.

[0032] When the earth in the bucket 50 is to be discharged from the bucket, the bucket 50 is first moved over, for example, a dump truck at a predetermined height h. The bucket is then rocked by the operation of the bucket cylinder 7 of the hydraulic shovel so that the movable bucket member 52 is locked slantingly or parallel to the floor of the truck, depending on the quality of the earth, and the movable bucket member 52 is opened concurrently with the rocking of the bucket. The movable bucket member 52 is opened by shortening the rod 56a of the hydraulic cylinder 56 by the supply of the working oil to the hydraulic cylinder 56 from the hydraulic pressure source in the hydraulic shovel body through the hydraulic pipe connecting port 34, the rotary joint 35 and the boss 36 shown in Fig. 10, thereby pivotally moving the links 57 about the pin 58 and urging the movable bucket member 52 by means of the links 59. At that time, the movable bucket member 52 is pivotably moved about the pin 55 of the hinge 54 and opened to the position shown by the dot-dashed line in Fig. 10. In this open state, the engaging portion 57a of each of the links 57 abuts against the corresponding stopper 59a on the link 59 to keep the links 57 and 59 substantially in alignment to keep the movable bucket member 52 open. The angle of the opening of the movable bucket member 52 can be adjusted by shifting the position at which the engaging portion 57a engages with the stopper 59a.

[0033] Since the movable bucket member 52 can be opened when the opening of the bucket 50 is directed slantingly or downwards, earth of any quality can be discharged smoothly from the bucket. Furthermore, although the center of the pivotal movement of the movable bucket member 52 is on the bottom plate 53, the earth can be discharged from the bucket 50 because the bucket can be positioned slantingly or parallel to the floor. The discharge height h can therefore be reduced as compared with a conventional bucket of the type which is opened by opening the bottom lid, so that the distance through which the hydraulic shovel is moved vertically during the discharge of the earth is reduced to improve the operation efficiency. This means that the height h of the banking can be increased.

[0034] After the discharge of the earth, the movable bucket member 52 is closed by supplying the working oil to the hydraulic cylinder 56 in a manner opposite to that in which it is supplied when the movable drum 52 is opened.

[0035] A narrow and deep ditch is dug by repeating vertical hole drilling operations in sequence at an adequate pitch. On the bottom of the ditch are scattered boulders of various sizes and the earth tumbled down from the periphery of the ditch. In this embodiment, the boulders and the earth remaining on the bottom of the ditch can be scooped from the ditch by, for example, the operation shown in Fig. 14 using the bucket 50 with the movable bucket member 52 being opened. During this operation, the movable bucket member 52 is opened, as shown by the dot-dashed line in Fig. 10, and the bucket 50 is hydraulically locked in that state so that it is not rotated by any external force. Earth and boulders are scooped out by moving the bucket 50 in the direction indicated by an arrow d by the operation of the hydraulic shovel. Since the surface of the movable bucket member 52 which makes contact with the bottom of the ditch is substantially flat, the earth 60 can be scooped into the movable bucket member 52 effectively. Once the bucket 50 has been filled with the earth 60 and the boulders, the movable bucket member 52 is closed, the bucket 50 is moved over a discharge site, such as over a dump truck, by the operation of the hydraulic shovel, and then the earth is discharged from the bucket in the manner described above. The earth deposited on the bottom of the ditch 48 shown in Fig. 9 can be removed to clean out the ditch by using the bucket 50 with its movable bucket member 52 opened as in the case of the scooping of the earth. In this way, the ditch can be efficiently cleaned out for a short period of time by moving the bucket 50, like the conventional excavation bucket which is attached to a hydraulic shovel.

[0036] Although not shown, the edges and the recessed members may be provided on the fitting portions between the fixed and movable bucket members 51 and 52, as in the case of the first embodiment, so that the torque of rotation can be transmitted to both the fixed and movable bucket members 51 and 52 smoothly. Furthermore, plate members may be provided along the opening of the bucket in such a manner that the distance between them increases towards the opening.

[0037] As will be understood from the foregoing description, the bucket according to the present invention is capable of making a narrow and deep ditch with improved efficiency and operability and earth discharge ability of the bucket. Furthermore, the bucket of this invention is capable of readily gripping, cleaning, scooping and discharging the boulders and the earth remaining on the bottom of the ditch.

Claims

1. A rotary bucket assembly for drilling a vertical hole, including a generally cylindrical bucket (6; 50), a bracket (15) through which said bucket is mounted on a hydraulically driven working machine (1; 1′), a hydraulic motor (17) on said bracket for rotating said bucket, and a bearing (19) disposed between said braket and said bucket, said bucket including a top portion (44) connected to said bearing and a bottom wall (46) provided with a plurality of cutters (24) for cutting earth and taking the thus cut earth into said bucket during rotation thereof, character­ized in that said bucket comprises a fixed bucket member (21; 51) which is partially opened at one side and at the bottom thereof, a movable bucket member (26; 52) which is pivotable about an axis (45; 55) disposed adjacent the opening of said fixed bucket member to open and close said opening, and pivoting means (29; 56, 57, 58, 59) provided on said fixed bucket member to pivotally move said movable bucket member over an arbitrary angle.

2. A rotary bucket according to claim 1, wherein said axis (45) is located adjacent the upper portion of said bucket.

3. A rotary bucket according to claim 1, wherein said axis (55) is located adjacent the bottom portion of said bucket.

4. A rotary bucket assembly according to Claim 1 or 2, wherein a pair of plates (37) are provided on the inner surface of said fixed bucket member along two side edges of the opening of said fixed bucket member such that the distance between the two plates increases towards the opening.

5. A rotary bucket assembly according to any one of Claims 1, 2 and 4, wherein edge members (28) are provided along side edges of the opening of one of the fixed and movable bucket members, while recessed members (27) are provided along side edges of the opening of the other of said fixed and movable bucket members such that each of the edge members is engaged with an associated recessed member during excavation.

6. A rotary bucket assembly according to Claim 1 or 3, wherein the movable bucket member is opened and closed by a link mechanism (57, 59) which is operative to keep the movable bucket member open when it is opened and which is foldable within the fixed bucket member when the movable bucket member is closed.

7. A rotary bucket assembly according to any one of Claims 1, 3 and 6, wherein said movable bucket member includes a portion having a generally U-shaped cross-­section the bottom of which is substantially flat.

Drawing