Abstract: The invention provides a reamer apparatus for a ground boring machine that is capable of restricting increase in drawing resistance when performing drawing of a buried pipe by using a reamer and of efficiently performing drawing operations of the buried pipe without degrading properties such as flexibility and rotatability. The reamer apparatus includes a reamer main body of substantially hollow conical shape that reduces in diameter towards a drawing side, and a rod connecting portion that provided at a narrow diameter end portion of the reamer main body and connected with a rod. The reamer main body is connected to a buried pipe through a coupling structure disposed on an opposite side to the rod connecting portion. The coupling structure has a Swivel joint that allows rotation of the reamer main body with respect to the buried pipe, wherein a main portion of the Swivel joint is substantially accumulated in the reamer main body.

Abstract: A ground drilling machine comprises a controller for automatically controlling the injection of working liquid according to the output signal output as a function of the rotating condition of the pilot head 20. When the pilot head 20 is driven forward or backward, working liquid can be injected by switching the working liquid transfer valve 111 so long as the pilot head 20 is revolving in order to improve the digging efficiency, the soil delivering efficiency and the cooling efficiency of the machine. The injection of working liquid can be suspended when the direction of propelling the pilot head 20 is shifted while stopping the revolution of the pilot head 20 because no working liquid is required for delivering the dug soil and cooling the leading body. Thus, working liquid can be injected always at an optimal rate depending on the rotating condition of the pilot head 20 to suppress any waste of working liquid and reduce the construction cost.

Abstract: A leading body for a ground drilling machine is provided which includes a main body which is tapered at a front end thereof to form a first sloped surface and a second sloped surface on opposite sides of the front end of the main body. A slant-cutting section extends from the main body substantially along the first sloped surface. And injection ports which are adapted to inject digging liquid are positioned in the slant-cutting section such that the injection ports inject digging liquid rearward with respect to a propelling direction of the leading body along an obtuse angle with respect to a rotation axis of the leading body and substantially along the second sloped surface.

Abstract: The invention provides a pipe burying method by which a diameter of a pilot hole can be efficiently and reliably enlarged depending on various types of soil and a burying operation of a buried pipe is made stable. The method involves preparing various types of platy members, selecting a platy member suitable for a soil type from among the various types of platy members on the basis of a soil type search of a burying place, and attaching the selected platy member to a reamer main body, thereby forming a reamer suitable for the soil type. The method further involves annexing this reamer at a front end of a rod in a pilot hole, and pulling out this rod from the pilot hole while rotating the reamer together with the rotation of the rod, thereby burying a buried pipe to be connected to the reamer in the earth.

Abstract: The invention provides a reamer apparatus for a ground boring machine that is capable of restricting increase in drawing resistance when performing drawing of a buried pipe by using a reamer and of efficiently performing drawing operations of the buried pipe without degrading properties such as flexibility and rotatability. The reamer apparatus includes a reamer main body of substantially hollow conical shape that reduces in diameter towards a drawing side, and a rod connecting portion that provided at a narrow diameter end portion of the reamer main body and connected with a rod. The reamer main body is connected to a buried pipe through a coupling structure disposed on an opposite side to the rod connecting portion. The coupling structure has a Swivel joint that allows rotation of the reamer main body with respect to the buried pipe, wherein a main portion of the Swivel joint is substantially accumulated in the reamer main body.

Abstract: A ground drilling machine comprises a controller for automatically controlling the injection of working liquid according to the output signal output as a function of the rotating condition of the pilot head 20. When the pilot head 20 is driven forward or backward, working liquid can be injected by switching the working liquid transfer valve 111 so long as the pilot head 20 is revolving in order to improve the digging efficiency, the soil delivering efficiency and the cooling efficiency of the machine. The injection of working liquid can be suspended when the direction of propelling the pilot head 20 is shifted while stopping the revolution of the pilot head 20 because no working liquid is required for delivering the dug soil and cooling the leading body. Thus, working liquid can be injected always at an optimal rate depending on the rotating condition of the pilot head 20 to suppress any waste of working liquid and reduce the construction cost.

Abstract: In a pilot head 20 to be used in a ground drilling machine, the injection ports 22A for injecting digging liquid are directed rearward and angularly separated from the axis of rotation N by an obtuse angle &thgr;1 (168E). With this arrangement, when digging a leading hole D from a starting pit, the flow rate of digging liquid flowing from the front end of the leading hole D toward the starting pit can be increased to efficiently deliver soil produced by the digging operation to remarkably improve the soil removing efficiency.

Abstract: A ground drilling machine includes a machine body a rod propelling device, a rod exchanging device and a support unit provided for the machine body for supporting the rod exchanging device. The rod propelling device has a frame movably mounted to the machine body. The frame is slidable on a support portion provided for the machine body. The rod exchanging device is attached to the frame of the rod propelling device via a transverse mounting member. The rod exchanging device is also supported on the support unit so as to be slidable on the support unit along with the movement of the rod propelling device without changing of its relative position to the rod propelling device. The rod exchanging device can be made light and compact because the rod exchanging device is supported by the support unit which is provided for the machine body and accordingly a large bending load is not applied to the main body portion of the rod exchanging device.

Abstract: A ground drilling machine comprises a machine body, a rod propelling device having a frame structure mounted to the machine body, a rod exchanging device mounted to the frame structure of the rod propelling device, and a support unit provided for the machine body for supporting the rod exchanging device. According to such structure, the ground drilling machine can be made light and compact.