JPH0738460Y2 - Earth drill - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earth drill for excavating a large-diameter vertical hole in a large-diameter cast-in-place pile construction method.

[0002]

2. Description of the Related Art A conventional earth drill, as shown in FIG. 3, supports a front frame 3 on a lower portion of a boom 2 which is erected upright on a front portion of a base machine 1 so that the boom can be elevated. The kerry bar rotation drive device 4 is mounted on the front frame 3, and the front frame 3 is attached to the boom 2 with the suspension rope 5.
The kelly bar 6 is hung from above and the kelly bar 6 is inserted into the torque transmission part of the kerry bar rotation drive device 4 and the kelly rope 7
At the upper part of the boom 2, wind the kerry rope 7 around the winch 8 of the base machine 2, wind up the winch 8, and lower and raise the kerry bar 6 up and down, and attach the excavation bucket 9 to the lower end of the kerry bar 6. The kerry bar rotation driving device 4 is driven to lower the kerry bar 6 while rotating the kerry bar 6 to excavate a pile hole.

Further, the boom 2 of the earth drill is used to carry out a crane work associated with excavation of a pile hole, for example, a crane for suspending a reinforced basket or trayy pipe when placing pile concrete after excavating a pile hole. In order to perform the work, the rope 3a linked to the front frame 3 is wound up and the front frame 3 is pulled toward the boom 2 side, so that the kerry bar rotation driving device 4, the kerry bar 6, and the excavation bucket 9 are stored in the pocket of the boom 2. Crane work is possible.

[0004]

[Problems to be Solved by the Invention] However, in the case of the above structure, since the front frame is suspended from the upper part of the boom by the suspension rope, the suspension rope is suspended during excavation due to the weight of the excavation bucket and excavation resistance due to rotation. Due to expansion and contraction, the mounting angle of the front frame became unstable, the accuracy of the excavation hole was poor, and the structure was complicated.

Therefore, an object of the present invention is to provide an earth drill which has a simple structure and excavates a vertical hole with high accuracy to improve the excavation efficiency and the piling work efficiency after excavation.

[0006]

In order to achieve the above-mentioned object, the present invention performs excavation work by rotating a kerry bar rotating drive device from a kerry bar that is hung from the upper part of a boom that is erected so as to be elevated on a base machine. In an earth drill, a link is connected to the kelly bar rotation drive device and the boom so that the link can be raised and lowered, and one end of a cylinder that supports the link from above is connected to the boom above and below the boom so that the link can be vertically swung. It is characterized by having done.

[0007]

[Operation] According to the above configuration, by locking the cylinder hydraulically during excavation work, the angle of the link does not change even if the kerry bar and the excavation bucket move up and down or the excavation resistance fluctuates. Since the mounting angle of the drive device can be maintained in a stable state, it is possible to excavate a vertical hole with high accuracy. Also, since the kelly bar rotation drive device can be moved up and down by the rotation of the link caused by the expansion and contraction of the cylinder, the kelly bar rotation drive device and the kelly bar can be stored in the boom pocket and the crane work can be performed easily by reducing the cylinder size. You can

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

The ground drill 10 pivotally attaches a lower end of a boom 12 to a front portion of a base machine 11, and an elevation rope 14 unwound from an elevation drum 13 provided at a rear portion of the base machine 11 above the boom 12. A gantry pulley 16 of a gantry 15 which is erected at the rear of the base machine 11 is connected to the hoisting rope 14 so that the boom 12 can be hoisted up and down.

A link 17 is rotatably provided at a lower end position of the boom 12 at a base end 17a thereof, and a tip end of the link 17 is rotatably supported by a front frame 19 having a kerry bar rotation drive device 18 mounted thereon. The link 17 is movably connected to the kerry bar rotary drive 18 and the boom 12.

The tip connecting portion 17b of the link 17 is provided at the center of gravity of the front frame 19 on which the kerry bar rotation driving device 18 is mounted, and holds the kerry bar rotation driving device 18 vertically.

A base end of the cylinder 20 is rotatably provided above the link 17 mounting position of the boom 12, and a tip end of a piston rod 21 of the cylinder 20 is mounted on a bracket 17c formed at an intermediate upper portion of the link 17. The cylinder 20 is rotatably provided, and is vertically swingably connected to the link 17 and the boom 12 so as to support the link 17 from above.

The torque transmitting portion (not shown) of the kelly bar rotation driving device 18 has a winding drum 2 of the base machine 11.
A kerry bar 25 hanging from a kelly rope 24 that is unwound from the boom sheave 2 via the top sheave 23 of the boom 12 is inserted, and an excavation bucket 26 is attached to the lower end of the kerry bar 25.

With this structure, the cylinder 20 is hydraulically locked during the excavation work, so that the piston rod 21 of the cylinder 20 can be moved even if the kerry bar 25 and the excavation bucket 26 move up and down or excavation resistance fluctuates. Does not expand and contract, the angle of the link 17 does not change, and the mounting angle of the kerry bar rotation drive device 18 can be maintained in a stable state, so that it is possible to excavate a vertical hole with high accuracy.

Further, as shown in FIG. 2, when the link 17 is raised and lowered by the expansion and contraction of the piston rod 21 of the cylinder 20, the kerry bar rotation drive device 18 moves up and down, so that the piston rod 21 of the cylinder 20 expands and contracts slightly. The adjustment can ensure the setting of the drill hole position.

Further, the piston rod 2 of the cylinder 20
By reducing the size of 1, the kelly bar rotation drive device 18 and the kerry bar 25 can be housed in the pocket of the boom 12 and can be raised and lowered integrally with the boom 12, so that the crane operation can be easily performed.

[0017]

As described above, the earth drill of the present invention connects the link to the kelly bar rotation drive device and the boom so that the link can be undulated, and supports the link from above from the link mounting position of the boom. Since the cylinders that are connected to each other can be undulated, by hydraulically locking the cylinders during excavation work, the angle of the links does not change even if there is vertical movement of the kerry bar and excavation bucket or fluctuations in excavation resistance. Since the mounting angle of the device can be maintained in a stable state, it is possible to excavate a vertical hole with high accuracy.
Also, since the kelly bar rotation drive device can be moved up and down by the rotation of the link caused by the expansion and contraction of the cylinder, the kelly bar rotation drive device and the kelly bar can be stored in the boom pocket and the crane work can be performed easily by reducing the cylinder size. You can

[Brief description of drawings]

FIG. 1 is a front view of an earth drill showing an embodiment of the present invention.

FIG. 2 is an enlarged front view showing a moving state of the Kerry bar rotation driving device.

FIG. 3 is a front view showing a conventional ground drill.

[Explanation of symbols]

10 ... Earth drill, 11 ... Base machine, 12 ... Boom, 17 ... Link, 18 ... Kerry bar rotation drive device, 19
... front frame, 20 ... cylinder, 21 ... piston rod, 25 ... kerry bar, 26 ... excavation bucket

Claims (1)

[Scope of utility model registration request] 1. An earth drill for excavating work by rotating a kerry bar hanging from an upper part of a boom erected on a base machine so that the boom can be elevated, and linking the kerry bar rotary drive device and the boom. The ground drill is characterized in that the cylinder is connected so as to be able to rise and fall, and one end of a cylinder for supporting the link from above is connected so as to be vertically swingable above the link mounting position of the boom.