JP2002349172A - Drilling bit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drilling bit capable of easily recovering a drill device, a rod or the like while leaving only the head part of the bit in a drilled hole at the end of drilling. SOLUTION: This drilling bit comprises the head part having a hard cutting edge at the tip and a shank part connected to a hammering device. The head part and the shank part are separately formed. The bit further comprises a connecting means capable of non-separably connecting the head part to the shank part in the normally rotating state in drilling and separating the both in the reverse rotation. As the connecting means, the combination of a fitting shaft part having a lug protruded in the radial direction with a recessed part to which the fitting shaft part is fitted to engage the lug with the inner wall thereof by the relative rotations is preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drill bit for use in down-the-hole drills and the like. More particularly, the present invention relates to a drill device for leaving a bit body in a drilled hole at the end of drilling. The present invention relates to a drill bit for easily collecting a rod or the like.

[0002]

2. Description of the Related Art A down-the-hole drill is a striking device that sinks into a drilled hole as the drill advances. Reference numeral 50 in FIG. 1 exemplifies a conventionally known down-the-hole drill. As shown in FIG. 1, a cylinder is formed in a cylindrical wear sleeve 51, and a piston 53 for striking is freely movable in the cylinder. It is provided in. High-pressure air is alternately supplied to the front chamber and the rear chamber of the piston by a valve provided at a rear portion to move the piston back and forth. A bit is fitted to the front end of the wear sleeve so as to be able to move back and forth, and the piston strikes the rear end face of the shank portion of the bit, whereby drilling is performed. Rotational force is transmitted to the bit through the spline fitting portion of the shank portion in the bore.

[0003]

The conventional bit used in the above-mentioned down-the-hole drill has a large-diameter head provided with a hard blade and a shank portion which is fitted to a wear sleeve. Since the outer diameter of the head is formed larger than the outer diameter of the wear sleeve, when pulling down the hole drill from the drilled hole at the end of drilling, slips etc. In many cases, the porosity did not come off and the porosity was significantly reduced.

In order to solve this problem, at the end of drilling, a bit attached to the tip of a cylindrical rod is pushed out with a reinforcing material such as a steel rod and cut off from the rod, leaving the bit and the reinforcing material. A drilling tool that can recover the waste has been considered. However, a practical drilling tool having a structure in which the bit can be firmly connected to the rod during the drilling and the bit can be easily separated at the end of the drilling has not been established yet.
Therefore, an object of the present invention is to provide a bit as a drilling tool that can firmly connect a bit at the time of drilling and can collect a drill or a rod at the end of drilling.

[0005]

In order to solve the above problems, the present invention employs the following configuration. That is, the drill bit according to the first aspect of the present invention is a drill bit including a head having a hard blade body provided at a tip end thereof, and a shank portion connected to a striking device. Coupling means for forming the head and the shank separately from each other, and the head and the shank are inseparably coupled in the forward rotation state at the time of drilling, and are separable in the reverse rotation state. Is provided.

The drill bit is divided into a main body having a large-diameter head and a shank portion connected to the drill drill device. Use while letting. At the end of drilling, the drill can be separated by turning it in the opposite direction, so that the drill body is separated by pulling the drill device backward through the connected rod, thereby disconnecting the bit body and shank the drill device. Can be collected along with it.

According to a second aspect of the present invention, there is provided a drill bit according to the present invention, wherein the head has a hard blade at its tip and a fitting integrally provided at the rear of the head. A bit body having a shaft portion, a fitting cylinder portion provided with a fitting shaft portion at a front end portion thereof, and a shank portion connected to a hitting device at a rear portion, and a fitting shaft of the bit body portion. The part is provided with a lug protruding in the radial direction, the fitting cylinder part is provided with a concave part in which the lug of the fitting shaft part is fitted, and the concave part is provided with the fitting shaft part and the lug. An opening that can be inserted into the recess from the front side, and a lug holding portion that can receive and hold the lug by rotating the fitting shaft inserted through the opening in a predetermined direction by a predetermined angle. The lug holding portion is provided with an inner wall for preventing an internal lug from deviating forward. It is characterized in that it is.

In the drill bit according to the second aspect, the bit body and the shank portion are integrally connected by fitting a lug and a recess which can be detached according to a relative angle between the bit body and the shank portion. At the time of forward rotation, that is, in a state where the two are combined and integrated, the drilling can be performed in the same manner as a normal bit. Also, when collecting the drilling device at the end of drilling, the coupling between the two can be released by reversing the shank and changing the relative angle with the bit body. The head is separated from the shank portion, and members after the shank portion can be easily collected.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a preferred embodiment of the present invention. The drill bit 1 is a down-the-hole drilling device (drill) 50.
The head and the shank portion, which are originally formed integrally, are formed separately and combined and integrated. That is, this drill bit 1
Is composed of a bit body 10 and a shank part 20.
The bit main body 10 includes a head 11 and a fitting shaft 12 integrated with the head. The head 11 has a larger outer diameter than a pipe (wear sleeve) 51 of a drill device described later, a plurality of hard blades 13,... Are provided with a plurality of forward and backward milling grooves 14,. Rear end face 11 of head 11
a is a plane perpendicular to the axial direction.

The fitting shaft portion 12 of the bit body has a smaller outer diameter than the head portion, and a pair of lugs (claws) 1 is provided at the front and rear middle portions.
7, 17 are protrudingly provided. The outer periphery of the lug 17 is formed as an arc-shaped surface having a predetermined length, and both front and rear ends in the longitudinal direction are formed as inclined surfaces in the direction in which the base portion expands. In the illustrated example, only one pair of lugs is provided in the diameter direction of the fitting shaft portion 12, but three or more lugs may be provided. A through hole 15 for air circulation is provided in the axial center portion of the bit main body 10, and discharge holes 16, 16 branching from the bottom of the through hole and opening to the front end face of the head are provided.

The shank portion 20 has a fitting cylindrical portion 21 with which the fitting shaft portion 12 is fitted integrally provided at the front end thereof, and a through hole 23 for air flow through a shaft portion of a rod portion 22 at the rear portion. Is provided. A concave portion 25 into which the lug 17 is fitted is formed in a hollow portion 24 of the fitting cylindrical portion 21. This recess 2
5 is a rotation transmitting plane 25a, 25a with which one side of the lug contacts when the drilling tool 1 rotates forward, and a separation plane 26a, 26a with which the other side contacts when rotating counterclockwise.
, And the outer periphery thereof is a window-like opening 25b, 25b. The angle between the two flat surfaces 25a and 26a is such that the bit does not separate during drilling, and is 45 degrees in the illustrated example, but is not limited to this.

The front end of the fitting cylinder 21 has a ring-shaped flat surface 27 of a predetermined width, a funnel-like portion 28 inside the fitting cylindrical portion 21, the fitting shaft 12 of the bit body and lugs 17, 17 from the front side of the recess. 25 is provided with an insertion opening 29 that can be inserted.

The bar portion 22 of the shank portion 20 is provided with a spline portion 30. A circumferential notch 31 is provided at a rear portion of the spline portion 30 so that the spline portion 30 is connected to the front portion 30a and the rear portion 3 by the notch portion.
0b. The notch 31 is fitted with a retainer ring (a ridge) described below for preventing the shank from coming out of the chuck of the drill device.

As shown in FIG. 1, the drill bit 1 is used by being attached to a front end of a pipe (wear sleeve) 51 of a drill device 50. The drill device 50 is a well-known down-the-hole type drill device, and includes a wear sleeve 51.
A piston 53 is held movably back and forth by a cylinder portion 52 provided in the inside, and a front chamber 52a on the front side of the piston is
The high pressure air is switched and supplied to the rear chamber 52b and the piston 53
Moves back and forth, and strikes the rear end face of the shank of the drill bit 1 when moving forward. The switching supply of the high-pressure air is performed by a valve 55 provided behind the piston and an air passage 57 provided on the inner wall of the wear sleeve. In the figure, 58 is an adapter, and 59 is a spring for pressing the valve.

At the time of drilling, a hollow rod R is connected to the rear part of the drill device 50 to apply a rotating force of an external rotating device to the rod and supply high-pressure air through the hollow portion of the rod. Will be The rotational force of the rod R is transmitted from the wear sleeve 51 of the drilling device to the shank portion 20 of the drill bit 1 via spline fitting, and rotates the bit head. The high-pressure air supplied through the rod R operates the valve 55 and the piston 53 constituting the percussion device to strike the drill bit 1, and opens the bit body head 11 of the drill bit 1. , Which are discharged from the discharge holes 16, 16 and are hit by the hard blades 13,... Of the bit head, are discharged rearward through a gap between the outer peripheral portion of the wear sleeve and the inner wall of the drilled hole.

During the drilling, the striking force of the piston 53 is transmitted to the rear end face of the shank 20 and transmitted from the ring-shaped flat surface 27 of the shank to the rear end face 11a of the head of the bit body. In this hole, the drill bit 1 is rotated forward (to the left as viewed from the rear) in the same manner as a conventionally known bit, so that the lug 17 of the bit body 10 is engaged with the recess 25 of the fitting cylinder 21. The rotational force is transmitted to the bit body by contacting the rotational force transmission plane 25a. In this state, the lug 17 is
5 is engaged with the inner wall surface (stopper surface) 25c on the front side, so that the bit main body 10 is prevented from deviating from the shank portion 20.

On the other hand, when the drilling apparatus 50 collects the drill R together with the rod R after the drilling of the predetermined depth is completed, the rod R is given reverse rotation. Then, the shank portion 20 of the drill bit 1 spline-fitted to the drill device 50 rotates in the reverse direction with respect to the bit body 10, and the lugs 17, 17 are recessed 25
Relative rotation until hitting the release planes 26a, 26a,
Since it comes to a position overlapping the insertion opening 29 of the fitting cylinder 21, the fitting shaft of the bit body 10 can be detached from the fitting cylinder of the shank 20. When the drill device 50 is pulled backward through the rod in this state, the large-diameter head 11 receives resistance against the backward movement due to the inner wall of the hole or a clogged slip, so that the bit main body 10 deviates from the shank portion 20. Therefore, the shank portion 20, the drill device 50, and the rod can be collected while the bit body 10 remains at the bottom of the drilled hole.

As described above, the drill bit 1 of the present invention can separate the bit body 10 from which the large-diameter head 11 is liable to be caught and not easily removed by a simple external operation (reverse rotation and traction). Therefore, the drill device 50 and the rod R can be easily collected. Since only the bit body 10 is not collected, it is not so uneconomical. Although the bit body remains in the drilled hole, the insertion of a reinforcing material, the injection of cement milk, and the like can be performed as usual. When a new drilling is performed, a new bit body 10 may be mounted on the shank portion and drilled in the same manner as described above.

[0019]

As is clear from the above description, in the drill bit according to the present invention, the shank portion connected to the drill device and the bit body are formed separately, and when drilling, the two are connected. The drill can be integrated and drilled, and when drilling is completed and the drilling device is to be recovered, the bit head that is easily caught can be cut off and other components can be recovered. Can be performed efficiently. Further, since the bit body can be separated by the reverse rotation of the rod and the towing operation, the separation can be easily and reliably performed by an external operation.

[Brief description of the drawings]

FIG. 1 is an external view (a), a front view (b), and a side sectional view (c) of a drill device equipped with a drill bit according to the present invention.

FIG. 2 is a side view of a drill bit showing a state where a bit body and a shank portion are separated.

FIG. 3 is a front view (a) and a side view (b) of a bit main body.

FIG. 4 is a rear view of the bit body.

FIG. 5 is a sectional view taken along the line AA in FIG. 3;

FIG. 6 is a front view (a) and a partial cross-sectional side view (b) of a shank portion.

7A and 7B are a front view and a side view in a state where the shank is rotated by 90 degrees.

FIG. 8 is a cross-sectional view of the fitting cylinder portion showing a state of normal rotation (a) and reverse rotation (b).

FIG. 9 is a cross-sectional view of a bit fitting portion showing a state of forward rotation (a) and reverse rotation (b).

10 is a sectional view taken along line AA, a sectional view taken along line BB, and a sectional view taken along line CC of the fitting tube portion in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drill bit 10 Bit body 11 Head 12 Fitting shaft part 13 Hard blade 17 Lug 20 Shank part 21 Fitting cylinder part 25 Depression 30 Spline part 50 Drilling device (Drilling device)

Continued on the front page (72) Inventor Hiromi Kawakami 36 Tojo-cho, Higashi-gun, Hiroshima Prefecture, Yamagata Lock Machine Co., Ltd. (Reference) 2D029 EC00

Claims (2)

[Claims] 1. A head provided with a hard blade at a tip thereof,
A drill bit including a shank portion connected to a striking device, wherein the head and the shank portion are formed separately, and the head and the shank portion are in a normal rotation state when drilling. A drilling bit, characterized in that a coupling means is provided which is inseparable from each other and which can be separated from each other in a reversed state. 2. A bit body having a head provided with a hard blade body at a front end portion and a fitting shaft portion integrally provided at a rear portion of the head portion, and the fitting shaft portion fitted to a front end portion. A fitting cylinder portion is provided, and a rear portion of the fitting cylinder portion is provided with a shank portion connected to the hitting device. A fitting shaft portion of the bit main body is provided with a lug protruding in a radial direction thereof. Is provided with a recess into which the lug of the fitting shaft is fitted, and the recess has an opening through which the fitting shaft and the lug can be inserted into the recess from the front side; A lug holding portion capable of holding and holding the lug by rotating the inserted fitting shaft portion in a predetermined direction by a predetermined angle is provided, and the lug holding portion prevents an internal lug from moving forward. A drill bit characterized in that an inner wall is provided.