JPS62133284A - Pit expanding bit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hole-expanding rock bit (hereinafter referred to as a hole-expanding bit) used for enlarging the diameter of a pilot hole previously drilled in rock or the like.

[Conventional technology] As a method of expanding the diameter of the bottom of an anchor bolt burial hole, blasting hole, etc. in civil engineering work, etc., there is a method of expanding the diameter using a special hole expansion device that expands the diameter at the bottom of the hole, and a method of expanding the diameter of a hole using high-pressure water. Methods such as spraying and expanding the holes are being adopted.

[Problem to be Solved by the Invention 1] However, in the conventional hole bottom diameter expansion method using the above-mentioned special diameter expansion device, the diameter of the bit inserted into the pilot hole is expanded using a hydraulic jack, etc. The structure becomes complicated,
Moreover, since the diameter of the bit inserted into the hole is necessarily large, there is a problem that it can only be used for expanding the diameter of a large-diameter pilot hole. In addition, the method using high pressure water is
Since a high pressure generator and a wastewater treatment device are required, there is a problem that the equipment is large and requires a large amount of space.

[Means for Solving the Problems] In order to solve the above problems and make it possible to easily expand the diameter of the hole bottom to a pilot hole with a relatively small diameter using small-scale equipment, we have developed this book. Komei offers the following hole expanding bits.

In other words, the hole-drilling human according to the present invention includes a chest portion having attachment means for a hole-drilling rod that transmits rotational force, and a blade pivotally attached to the body portion so as to be freely rotatable in the front-rear direction, The blade protrudes from the outer diameter of the body to both sides,
The protrusion amount is increased or decreased by rotation, and when the front end of the bit is pressed against a rock, etc., the front end of the blade is rotated backward by the reaction force, and the amount of lateral protrusion is increased. It is characterized by increasing support.

[Operation 1] This human is used by attaching the trunk to the tip of the drilling rod. When inserting the blade into a pilot hole previously drilled in the rock, the human body is supported so that the amount of protrusion from the body is reduced, and the protrusion of the blade is regulated by the side wall of the pilot hole.
When the blade comes into contact with the bottom of the hole and a rough thrust is applied from above, the front end of the blade rotates backwards due to the reaction force and receives a force that protrudes to the side beyond the outside diameter of the body. . In this state, rotational force is transmitted from the drilling rod, so that the diameter of the bottom of the hole is expanded by the laterally protruding blade.

[Embodiment 1] The figure shows an embodiment of the present invention, in which the hole-expanding tool 1 has a body 2 and a blade 3, and the blade has a groove formed at the front end of the body 2. 5 and pin 6 to land in one ward.

The body 2 is provided with a screw hole 11 as a means for attaching the hole rod 10, and the hole rod 10 is inserted into the screw hole 11.
The threaded portion 10a of the holder is screwed into the holder. A large diameter portion 12 is formed at the bottom of the screw hole 11, and a recess 13 is formed roughly at the bottom. And large diameter part 1
A pair of through holes 17 are drilled from 2 through the arm portions 2a, 2a on both sides of the groove portion 5 to reach the pin hole 15.

An annular groove 19 is formed on the outer periphery of the pin 6 inserted into the pin hole 15 at the position of the through hole 17 . Note that the front end opening of the through hole 17 is closed by a plug 20.

A blowhole 22 is opened at the bottom of the recess 13.

The blowhole 22 is located at an angle α from the center position of the bit body 2.
(approximately 25 degrees) and opens into the groove portion 5.

In the illustrated example, a circular spacer 24 for compressed air distribution is fitted in the large diameter portion 12 of the screw hole 11, and the drilling rod 11 presses the screw hole 11 through the spacer 24. It is supposed to be done. The spacer 24 has a through hole 25 in the front-rear direction in the center thereof, and a diametrical distribution hole 26 which can be accessed from the middle of the through hole to the side surface. The number of distribution holes 26 may be one or two or more. The compressed air discharged from the water hole provided in the core of the drilling rod into the through hole 25 passes through the through hole and is discharged from the blowhole 22 to the front outside.
7 and is supplied to the gap between the hole wall of the pin hole 15 and the pin 6, thereby preventing rocks and the like from entering the gap.

The blade body 3 is formed into a substantially diamond shape, and has a pin hole 27 bored in the center. A carbide tip 31 serving as a peripheral edge or a cutting edge is soldered to the projecting portions 30 on both sides of the pin hole 27, and
The tip 32 of the overhang 30 is rounded.

A groove-like notch 35 is formed in the middle of the blade 3 in a direction parallel to the long axis of the blade, and a groove-like notch 36 is formed in the opposite direction in a direction perpendicular to the long axis. is formed. Also, pin holes 27 are inserted from both grooved notches 35 and 36.
A set bolt 40, 41 for fixing the pin 6 to the blade body is screwed into each screw hole.

Note that at one end of the groove portion 5 there is a slope portion 42 that escapes to the rear.
is formed, and when the side surface of one of the protruding parts 30 of the blade body 3 comes into contact with the bottom surface of the groove of this inclined part 42, the protruding part 30
The cutting edge E formed on the other side of the overhang 30 and the outer cutting edge E of the overhang 30 on the opposite side are parallel to the axis of the bit, and the inclination angle of the bottom surface of the notch 35 is It is formed to be equal to the inclination angle α of the hole 22.

This hole expanding bit 1 is used by being screwed onto the tip of a drilling rod 10 attached to a rotary drilling device (not shown). During drilling, the bit is inserted into the pre-drilled hole 50 while being rotated and thrusted by the drilling device via the drilling rod.

At this time, the blade body 3 is moved laterally as shown in FIG. is maintained in an upright position with the least amount of protrusion.

When the bit 1 is inserted sufficiently deeply and the tip 32 of one of the protruding parts 30 of the blade 3 (which is the front end of the blade 3) reaches the completion of the pilot hole 50, the drilling rod 50 is inserted. The blade body 3 is about to be rotated in the direction of the arrow X by the thrust transmitted through the blade. Therefore, the upper and lower tips 32 of the blade 3 protrude laterally and cut the inner wall of the prepared hole 50 at these positions. In this way, the diameter of the large portion of the pilot hole is expanded, but as the side wall of the pilot hole is cut, the amount of lateral protrusion of the blade 3 gradually increases, so the long axis of the blade 3 increases. The hole enlargement progresses until the hole becomes approximately perpendicular to the center line of the prepared hole 50.

Once the hole has been sufficiently expanded, the drilling rod 10 is pulled up together with the hole expanding bit 1. At this time, the blade 3 is returned to its original upright position due to the regulation by the inner wall of the hole expanding section 51 and the pressure of compressed air from the blowhole 22. It is rotated to the state,
The amount of lateral protrusion decreases. Therefore, it can be easily handled from the pilot hole 50.

This hole expansion bit 1 expands the diameter of the cutting edge by simply pressing the cutting edge of the bit against the enlarged part of the prepared hole, and rotates the side wall of the enlarged part of the prepared hole, so special equipment such as a hydraulic cylinder is required to expand the bit diameter. is not necessary. Therefore, it is possible to enlarge a prepared hole with a simple structure and a relatively small scale.

"Devices of the Invention" As explained above, the hole expanding bit according to the present invention does not require large-scale equipment, has a simple structure, and is capable of expanding pilot holes of relatively small diameters. It turned out to be the best it could be.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of one embodiment of the present invention, FIG. 2 is a bottom view thereof, FIG. 3 is a Z-7 cross-sectional view, and FIG. 4 is an explanatory diagram of the state of use. 1... Hole expansion bit 2... Body 3... Blade 6... Pin 10... Drilling rod 11... Screw hole 17... Through hole 22... Blow hole 30・
・・Protrusion part

Claims (1)

[Claims] (1) A body having a means for attaching to a drilling rod that transmits rotational force, and a blade pivotally attached to the body so as to be rotatable in the front and back direction, and the blade is arranged from the outside diameter of the body. It is provided so that it protrudes to both sides and the amount of protrusion increases or decreases by rotation, and when the front end of the bit is pressed against a rock or the like, the front end of the blade body is rotated rearward by a reaction force, A hole expanding bit characterized by being supported so that the amount of lateral protrusion thereof increases.