JPH0236753B2 - KAKUKOBITSUTO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hole expansion bit, specifically for drilling a hole expansion part for installing an expanded diameter anchor anchor in a rock layer. Regarding hole bits.

Conventionally, a boring machine is used to drill a predetermined length of a hole with a constant diameter in the soil layer, and then a blade bit is opened to expand the diameter of the primary hole to provide an anchorage. However, blade bits are used in soft ground due to the small bearing area of the blade by the bit body (blade mounting window frame), the small cross-sectional area of the blade, and the heavy burden of the hinge on the blade. It was used on ground that did not contain rocks or boulders, and the blade broke when it touched hard rock. In addition, with bits whose blades open vertically and horizontally, if there are boulders mixed in the soil, the blade and boulders may rotate together, or the blade may become idle, making it impossible to expand the hole.

As described above, with conventional hole expanding bits, it has been impossible to drill a hole expanding portion in the ground or rock layer where boulders exist.

The present invention has improved 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 expanded diameter blade is open, and holes can be easily expanded even in hard rock layers. The purpose of the present invention is to provide a hole expansion bit that can be used without any trouble.

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the hole expanding bit of the present invention before operation. A blade attachment window 11 is opened in the cylindrical hole expanding bit body 1 in the length direction. The blade mounting window 11 has an approximately triangular or sector-shaped enlarged diameter blade 1.
2 is pivoted by a pin 13 at an acute angle portion with its long side 15 facing inside the body of the cylindrical hole-expanding bit, and is provided inside and outside the body of the bit so that the cutting edge 14 faces downward (that is, in line with the excavation direction) so as to be freely retractable. It is being A driving force transmitting member 2 for transmitting rotational driving force is screwed into the tip of the bit body 1.

A water passage hole (not shown) passes through the diameter-expanding piston 3, and circulating water is discharged from a nozzle 33 at the tip. A drive shaft 4 is fixed to the other end. The drive shaft 4 also has a water hole (not shown) extending through the shaft center.

The diameter-expanding piston 3 is housed within the bit body, and the conical surface 31 at the tip of the diameter-expanding piston 3 and the long side 15 of the diameter-expanding blade are in contact with each other, so that the cutting edge 14 is kept from protruding outside the bit body. ing.

A piston mount 5 is screwed into the distal end of the bit body 1, and a crown mounting member 6 is connected thereto. The crown mounting member 6 has a crown 7
is installed.

Next, the function of this hole expanding bit will be explained.

First, a boring machine is driven to rotate to drill a predetermined length and a predetermined diameter hole in the rock layer to form a primary drilling section in the rock layer.

The hole expanding bit of the present invention is used to form a hole expanding portion in a rock layer.

The target ground for drilling is hard rock or weathered rock, which has relatively strong strength and whose rock condition does not turn to sand when a hole is drilled, but of course, it may also be sandstone or gravel.

When the crown 7 reaches the hole bottom of the primary drilling section and rotates while pressing the drive shaft 4 downward, the diameter expanding blade 12 first has its long side 15 facing the conical surface 31 of the diameter expanding piston, then the circumferential surface. 32, the cutting edge 14 gradually protrudes out of the bit body, and finally the diameter-expanding piston 3 reaches the piston holder 5 and stops (FIG. 2). In this state, the drive shaft 4 is rotated to apply propulsion pressure and the hole is drilled to a predetermined length.

After forming an enlarged hole portion of a predetermined length, when the rod 9 connected to the drive shaft 4 with a coupler 8 is pulled up, the diameter-expanding piston 3 rises, and the long side 15 of the diameter-expanding blade is aligned with the diameter-expanding piston. The contact with the circumferential surface 32 is released, the cutting edge 14 is accommodated in the bit body by being pushed by the hole wall of the primary drilling portion of the rock layer, and the hole expanding bit is pulled up in the state shown in FIG.

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

According to the present invention, (1) the diameter expanding blade is plate-shaped, and the cutting edge is also directed downward, that is, in the digging direction, and its long side is held together with the hinge by the blade mounting window frame; ) and the long side of the expanding blade are large, and can withstand large drilling resistance such as when drilling in rock layers. The effective drilling pressure is large, and there is no risk of co-rotation even if there is a boulder, etc. (3) The expanded diameter blade with open wings cuts the circumferential surface of the diameter expanded piston. Since the entire length is supported by the mounting window frame, there is less stress on the hinge and less stress on the diameter expansion blade. (4) The diameter expansion blade is wedge-fed by the conical surface at the tip of the diameter expansion piston. Since the blades are opened, there is no complicated mechanism and there is no failure. (5) The effective diameter expansion gauge Δ can be adjusted by appropriately selecting the length of the diameter expansion blade according to the rock condition, and the diameter expansion blade can be replaced. (6) As the crown at the tip drills a small diameter hole and the diameter expanding blade simultaneously expands the hole, the small diameter hole at the tip acts as a guide to prevent shaft wobbling and ensure reliable expansion. A hole can be formed.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the hole expanding bit of the present invention, showing a state in which the diameter expanding blade is closed, and FIG. 2 shows a state in which the diameter expanding blade is opened. FIG. 3 is an explanatory diagram of the bearing pressure area A between the diameter expanding blade and the hole expanding bit body. DESCRIPTION OF SYMBOLS 1... Cylindrical hole expanding bit body, 11... Blade mounting window, 12... Plate diameter expanding blade, 13...
...Pin, 14...Blade tip, 2...Driving force transmission member,
3...Expanding diameter piston, 31...Conical surface, 32...
... Circumferential surface, 4 ... Drive shaft, 5 ... Piston mount,
6...Crown mounting member, 7...Crown, 8...
...Coupler, 9... Rod, A... Bearing area,
Δ...Effective diameter expansion gauge.

Claims (1)

[Scope of Claims] 1. A cylindrical hole-expanding bit body having a blade attachment window opened in the length direction, with the long side facing inside the bit body,
It is pivotally supported at its acute angle part, and when drilling the hole expansion part, the circumferential surface of the diameter expansion piston and its long side are in contact with each other along its entire length, and the long side is held between the blade mounting window frame. , the cutting edge protrudes outside the bit body and coincides with the drilling direction, and when the hole expansion part is not drilled, the contact between the diameter expansion piston and its long side is released and the cutting edge does not protrude outside the bit body. It consists of a generally triangular or fan-shaped plate diameter-expanding blade provided in the blade mounting window, and a diameter-expanding piston that is connected to the drive shaft and moves within the bit body to allow the cutting edge of the diameter-expanding blade to move in and out. A hole expanding bit characterized by: 2. A cylindrical hole-expanding bit body with a blade mounting window opened in the length direction, with the long side facing inside the bit body,
It is pivotally supported at its acute angle part, and when drilling the hole expansion part, the circumferential surface of the diameter expansion piston and its long side are in contact with each other along its entire length, and the long side is held between the blade mounting window frame. , the cutting edge protrudes outside the bit body and aligns with the drilling direction, and when the hole is not drilled in the hole expansion section, the contact between the circumferential surface of the diameter expanding piston and its long side is released, and the cutting edge is aligned with the bit body. so as not to protrude outward,
A substantially triangular or sector-shaped plate diameter-expanding blade provided in the blade mounting window and a conical tip that is connected to the drive shaft and moves within the bit body to allow the cutting edge of the diameter-expanding blade to move in and out. A hole expanding bit characterized by consisting of a diameter expanding piston. 3. A cylindrical hole-expanding bit body with a blade mounting window opened in the length direction, with the long side facing inside the bit body,
It is pivotally supported at its acute angle part, and when drilling the hole expansion part, the circumferential surface of the diameter expansion piston and its long side are in contact with each other along its entire length, and the long side is held between the blade mounting window frame. , the cutting edge protrudes outside the bit body and coincides with the drilling direction, and when the hole is not drilled in the hole expansion section, the contact between the circumferential surface of the expansion piston and its long side is released, and the cutting edge protrudes outside the bit body. A generally triangular or fan-shaped plate diameter-enlarging blade is provided in the blade mounting window so as not to protrude, and a tip portion is connected to the drive shaft and moves within the bit body to allow the cutting edge of the diameter-expanding blade to move in and out. A hole expanding bit comprising a diameter expanding piston having a conical shape, and a crown connected to a distal end of a bit body.