JPS59141631A - Drilling of large-diameter pit - Google Patents

Abstract

PURPOSE:To reduce burden of a blade by a method in which the diameter-expanded blade of a plate of a fun shape is pivotally supported with an acute angular part to the fitting window of a bit body housed with a diameter-expanded piston, and a cutting edge whose long side is contacted with the face of the piston is projected from the bit body. CONSTITUTION:The diameter-expanded blade 12 of an almost triangular or fun- shaped plate is pivotally supported with a pin 13 to the blade fitting window 11 opening in the longitudinal direction of a clindrical pit-expanding bit body 1. The cutting edge 14 is provided downwards and in a freely coming-in and out manner to the inside and outside of the body 1. A diameter-expanded piston 3 is slidably housed in the body 1, and the long side 15 of the blade 12 is contacted with the conical face 31 of the piston 3. The pressure-supporting area A between the body 1 and the blade 12 can thus be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for drilling a hole in a hole, and more particularly, to a method for drilling a hole in a hole for fixing an integral anchor when constructing an earth anchor.

Conventionally, after drilling a predetermined length with a constant diameter using a crown at the tip,
The diameter of the fixing part was expanded and the hole was drilled by closing the blade bit, but the blade bit has a small bearing area on the bit body of the blade, a small cross-sectional area of the blade, and a hinge with respect to the blade. The blades were damaged when they came into contact with hard rocks due to heavy loads. In addition, if the blade is vertically opened horizontally, if there are boulders mixed in the soil, the blade and boulders may rotate together,
The blade was spinning idle, making it impossible to expand the hole.

The present invention aims to improve these drawbacks, and there is no danger of co-rotation even when there are boulders, etc., the load on the hinge is reduced even when the diameter expansion blade is opened, and the hole expansion part can be easily expanded. The purpose is to provide a hole method.

The present invention will be described in detail. FIG. 1 is an explanatory view of the hole expanding bit used in the present invention, showing the state before operation. A blade attachment window is opened in the lengthwise direction of the cylindrical hole expanding bit body. In the mounting window //, a substantially triangular or fan-shaped plate diameter expanding blade /2 is pivotally supported by a pin /3 at an acute angle with its long side facing inside the hole expanding bit body, and the cutting edge /2 is mounted inside and outside the hole expanding bit body. The game is provided facing downward and can appear freely. At the end of the hole-expanding bit body, there is a driving force transmission member that transmits the rotational force! are connected. The diameter-expanding piston 3 is penetrated with a water supply hole for supplying W ring water.
A prismatic drive 'l@4' is fixed at the upper end.
The diameter-expanding piston 3 is housed in the hole-expanding bit body, and the conical surface 3/ of the diameter-expanding piston and the long side /j of the diameter-expanding blade/2 are in contact with each other, and the tip /l is housed inside the hole-expanding bit body. ing.

A piston paper holder is screwed into the distal end of the hole-expanding bit body, and a crown attachment member B is connected to the hole-expanding bit body. A crown 7 is provided in the crown attachment portion tAB.

Next, the method for drilling an enlarged hole according to the present invention will be explained.

First, the crown 7 at the tip is rotated to drill a small diameter hole of a predetermined length. Next, in order to enlarge the diameter of the fixing part and drill an enlarged hole, press the drive shaft downward while the crown 7 is in contact with the bottom of the small diameter hole, and the diameter enlargement screw 3 is pressed downward. The diameter-expanding blade 2 contacts the circumferential surface 3.2 of the diameter-expanding piston 3, and the cutting edge protrudes outside the hole-expanding bit body (Fig. 2), and is driven in this state. The shaft t is driven to rotate.

After drilling a hole of a predetermined length, when the rod connected to the drive shaft g with a coupler g is pulled up, the diameter expansion piston 3 rises, and the long side 15 of the diameter expansion blade/2 is connected to the diameter expansion piston 3. The abutment with the circumferential surface 32 of the blade is released, the tip is pushed against the hole wall of the small diameter hole, and the tip is accommodated in the hole expanding bit body, and the long side of the expanding blade and the cone of the expanding piston are The hole-expanding bit is pulled up with the surfaces 3/ in contact (FIG. 1).

Note that during drilling, slime is removed by circulating water from the nozzle 33.

According to the present invention, since the diameter expanding blade is plate-shaped and its long side is supported by the diameter expanding blade window frame together with the hinge, the bearing pressure area A between the hole expanding bit body and the diameter expanding blade is large. The open-winged enlarged diameter blade, which can withstand large drilling resistance, is in contact with the circumferential surface of the diameter enlarged piston along its entire length, so there is less stress on the hinge and less stress on the diameter enlarged blade. , Since the cutting edge points downward, the rod axial force is directly transmitted to the drilling ground, the effective drilling pressure is large, and there is no risk of co-rotation even if there are boulders, etc. Select the length of the expanding blade appropriately. By doing so, it is possible to expand the hole to any effective diameter expansion gauge Δ, and the diameter expansion blade can be easily replaced.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams of the hole expanding bit used in the present invention, and show a state in which the diameter expanding blade is closed and a state in which the diameter expanding blade is opened, respectively. FIG. 3 is an explanatory diagram of the bearing pressure area A between the diameter expanding blade and the hole expanding bit body.

Claims (1)

[Claims] When drilling a small diameter hole with a constant diameter in the ground, and then expanding the diameter of the anchoring part with a hole expansion bit to drill the expanded hole,
A diameter expanding piston is movably accommodated in a cylindrical hole expanding bit body with a blade mounting window opened in the length direction, and a substantially triangular or fan-shaped plate diameter expanding blade is pivoted into the mounting window with its acute angle. the long side of the blade is brought into contact with the circumferential surface of the piston, the cutting edge of the blade is projected outside the hole expanding bit body, and the hole expanding bit is used as a fixing part; A drilling method for expanding holes.