Double-wall drill bit for pneumatic rotary drilling rig

Abstract

The present invention belongs to the technical field of construction engineering, and relates to a double-wall drill bit used in a pneumatic rotary drilling rig, which is suitable for construction in hard rock formations. The effects are as follows: while ensuring the clearance size of the original drill bit, an inner tube is added to the outside of the original tube drill to ensure airflow and make full use of the exhaust gas; the drill bit air outlet hole set on the drill bit base allows excess exhaust gas to be discharged from the drill bit air outlet hole, and the exhaust gas can blow the broken rock debris out of the hole, so that the pick of the drill bit can contact the rock more closely, thereby improving the drilling rate; the traditional pneumatic drilling rig crushes all the rocks and then discharges them, while the double-wall drill bit adopts a cutting method, and the complete rock core can be taken out after cutting the rock, thereby improving the drilling efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of construction engineering and relates to a double-wall drill bit used for a pneumatic rotary drilling rig, which is suitable for hard rock stratum construction. Background Art

[0002] The foundation pit support and pile foundation construction of construction projects are mostly drilled by rotary drilling rigs. The rotary drilling rigs drill by rotary cutting, and have the characteristics of large output torque, large axial pressure, high drilling efficiency, good hole quality, small environmental pollution, convenient walking and shifting, etc. By configuring the appropriate drilling tools, it can efficiently drill holes in various soil layers, gravel layers and even soft-medium-hard joints in bedrock and other geological conditions, and achieve good drilling results.

[0003] Traditional rotary drilling rigs drill by rotary cutting. For relatively complete medium-hard rock bedrock with undeveloped bedding fissures, the drilling efficiency is extremely slow and the wear and tear of drilling tools is large. With the development of the industry, pneumatic rotary drilling rigs are more commonly used, and pneumatic rotary drilling rigs have the advantage of fast hole-making efficiency.

[0004] At present, most of the existing pneumatic rotary drilling rigs on the market have the following shortcomings during use: when the pneumatic rotary drilling rig is in construction, the gas drives the rotary drilling bit to perform impact drilling through the impactor, and the excess exhaust gas is discharged from the connection between the top of the rotary drilling bit and the drill rod, without recycling the exhaust gas, and the slag taken into the drill bit is easily blown into the hole while exhausting the gas, causing labor-intensive. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the existing pneumatic rotary drilling bit technology and to propose a double-wall drill bit used in a pneumatic rotary drilling rig.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A double-wall drill bit used in a pneumatic rotary drilling rig comprises a drill bit outer cylinder 1, a drill bit inner cylinder 2, a drill bit base 10 and a pick 9;

[0008] The drill bit outer cylinder 1 is an integrated structure, which is divided into three parts: upper, middle and lower. Among them, the upper part and the lower part are straight cylinder structures, and the diameter of the upper cylinder is larger than that of the lower cylinder; the upper surface of the upper cylinder is an open structure, and the center of the lower surface is opened with a hexagonal opening of the same size as the hexagonal joint 5. A plurality of square openings 7 are symmetrically arranged on the upper part of the upper cylinder as a rotating rod joint, so that the rotating rod is installed on the upper cylinder. Two circular openings are also symmetrically arranged on the upper part of the upper cylinder. The impactor is inserted into the drill bit from the upper cylinder, and the rotating rod and the impactor are connected by the cooperation of the connecting rod and the circular opening; the lower surface of the lower cylinder is an open structure, and the center of the upper surface is A compressed air inlet 6 is provided; the middle part includes a hexagonal joint 5 and a plurality of wing plates 4, the hexagonal joint 5 is a hexagonal cylinder structure, and its upper and lower surfaces are respectively connected to the lower surface of the upper cylinder and the upper surface of the lower cylinder, and the hexagonal joint 5 is coaxial with the upper cylinder and the lower cylinder; the wing plates 4 are symmetrically arranged on the outside of the hexagonal joint 5, the bottom end of the wing plate 4 is connected to the upper surface of the lower cylinder, the top end is connected to the lower surface of the upper cylinder, and the inner side is connected to the outer wall of the hexagonal joint 5, so as to improve the overall stability of the drill bit outer cylinder 1; the impactor is connected to the double-wall drill bit through the hexagonal joint 5, and the air outlet of the impactor is connected to the compressed air inlet 6;

[0009] The drill base 10 is a circular plate-shaped structure, which is installed at the bottom of the drill outer tube 1; the drill inner tube 2 is a cylinder with an open bottom, which is located in the lower cylinder of the drill outer tube 1, and the bottom of the drill inner tube 2 is fixedly connected to the inner edge of the drill base 10 as a whole, so that a double-wall drill cavity is formed between the outer wall of the drill inner tube 2 and the inner wall of the drill outer tube 1, which serves as an air passage 8;

[0010] The picks 9 are installed on the drill base 10 at equal intervals along the circumferential direction, and a drill air outlet 3 is opened on the circumference between two adjacent picks 9, and the drill air outlet 3 is used to blow away rock slag.

[0011] Beneficial effects of the present invention:

[0012] (1) The connection method between the top of the double-wall drill bit and the drill rod makes it faster and more convenient to remove the drill bit.

[0013] (2) While ensuring the clearance size of the original drill bit, an inner tube is added to the outside of the original tube drill to ensure air flow and make full use of the exhaust gas.

[0014] (3) The drill bit air outlet hole provided on the drill bit base allows excess exhaust gas to be discharged from the drill bit air outlet hole. The exhaust gas can blow the broken rock debris out of the hole, so that the pick of the drill bit can contact the rock more closely, thereby improving the drilling rate.

[0015] (4) Traditional pneumatic drills crush all the rocks and then discharge them, while double-wall drill bits use a cutting method to cut the rocks and then remove the complete core, thereby improving drilling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A top view of a double-wall drill bit of the present invention;

[0017] Figure 2 A bottom view of the double-wall drill bit of the present invention;

[0018] Figure 3 It is a cross-sectional view of the double-wall drill bit of the present invention.

[0019] In the figure: 1 drill bit outer tube; 2 drill bit inner tube; 3 drill bit air outlet; 4 wing plate; 5 hexagonal joint; 6 compressed air inlet; 7 square opening; 8 air outlet channel; 9 cutting teeth; 10 drill bit base. DETAILED DESCRIPTION

[0020] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and technical solutions.

[0021] like Figure 1-3 As shown, a double-wall drill bit used in a pneumatic rotary drilling rig of the present invention comprises a drill bit outer cylinder 1, a drill bit inner cylinder 2, a cutting tooth 9 and a drill bit base 10.

[0022] The drill bit outer tube 1 is divided into three parts: upper, middle and lower. The structures of each part are as follows:

[0023] (1) The upper surface of the upper cylinder is an open structure. A square opening 7 is provided on the upper cylinder for installing a drill rod. A circular opening is also provided for connecting the drill rod to the impactor through a connecting rod. A hexagonal opening having the same size as the hexagonal joint 5 is provided at the center of the lower surface of the upper cylinder. After the top end of the double-wall drill bit is plugged into the drill rod, a latch-type connection is adopted. The advantage of this connection method is that the drill bit can be removed more quickly and conveniently.

[0024] (2) The middle part is a hexagonal joint 5 and a wing plate 4. The hexagonal joint 5 is used to connect the impactor. The wing plate 4 is arranged on the periphery of the hexagonal joint 5 to provide stability for the drill bit outer tube 1.

[0025] (3) The lower surface of the lower cylinder is an open structure, and a compressed air inlet 6 is opened in the center of the upper surface. The air outlet of the impactor is connected to the compressed air inlet 6.

[0026] The drill base 10 is a circular plate-shaped structure, which is installed at the bottom of the drill outer tube 1; the drill inner tube 2 is a cylinder with an open bottom, which is located in the lower cylinder of the drill outer tube 1, and the bottom of the drill inner tube 2 is fixedly connected to the inner edge of the drill base 10 as a whole, so that a double-wall drill cavity is formed between the outer wall of the drill inner tube 2 and the inner wall of the drill outer tube 1, which serves as an air passage 8;

[0027] The drill base 10 is a circular plate-shaped structure and is installed at the bottom of the drill outer tube 1 .

[0028] The drill bit inner tube 2 is a cylinder with an open bottom, which is located in the lower cylinder of the drill bit outer tube 1. The bottom of the drill bit inner tube 2 is fixedly connected to the inner edge of the drill bit base 10 as a whole, so that a double-wall drill bit cavity is formed between the outer wall of the drill bit inner tube 2 and the inner wall of the drill bit outer tube 1, which serves as an air passage 8. While ensuring the clearance size of the original drill bit, a layer of tube drill is added to the outside of the original tube drill, and a 20mm gap is left between the drill bit inner tube 2 and the drill bit outer tube 1 to ensure airflow.

[0029] The cutting teeth 9 are installed on the drill bit base 10 at equal intervals, and a drill bit air outlet hole 3 is opened on the circumference between two adjacent cutting teeth 9, so that excess exhaust gas can be discharged from the drill bit air outlet hole 3. The exhaust gas can blow the broken rock debris out of the hole, so that the cutting teeth of the drill bit can contact the rock more closely, thereby improving the drilling rate.

[0030] The advantage of the drill bit air outlet 3 over the traditional drill bit is that the exhaust position is closer to the slag, and the slag blowing effect is better than the slag blowing method of the traditional pneumatic drill bit. The traditional drill bit exhaust hole is at the top of the drill bit, which is far away from the location of the crushed slag, and there is a core in the barrel drill, resulting in the slag blowing being not very targeted. The barrel wall of the double-wall drill bit is two layers, and the exhaust gas can be discharged from the top of the drill bit to the bottom of the drill bit. The exhaust hole is reserved between the two pick teeth so that the exhaust gas can be discharged from the exhaust hole, which can better blow out the slag in the hole.

[0031] The working process of the present invention is as follows:

[0032] 1. After the pile foundation is opened, the rotary drilling rig first uses a pick drill bit to construct the upper soil layer (including backfill soil, clay, etc.).

[0033] 2. After the construction of the upper soil layer is completed, the double-wall drill bit of the present invention is replaced after entering the rock layer. First, the pick drill bit is disassembled, and then the double-wall drill bit is placed upright on the ground. The drill rod is moved so that the hexagonal joint of the impactor overlaps with the double-wall drill bit, and then the drill rod is lowered so that the hexagonal joint (convex) on the impactor is inserted into the hexagonal joint 5 of the drill bit. The double-wall drill bit is installed on the drill rod by inserting a pin into the circular opening of the upper cylinder.

[0034] 3. Start the air compressor, open the air tank, lower the drill rod into the hole, and perform pneumatic rotary drilling. The airflow passes through the high-pressure pipe-air tank-winch-drill rod upper end lifter-drill rod to the impactor. Under the action of wind pressure, the impactor drives the double-wall drill bit to vibrate at high frequency. Then the airflow enters the air passage 8 in the drill bit outer tube 1 from the compressed air inlet 6, and then comes out from the drill bit outlet 3, so that the rock is crushed and blown out by wind pressure, and the rock is cut to form a complete rock core and enter the drill bit inner tube 1.

Claims

1. A double-wall drill bit for a pneumatic rotary drilling rig, characterized in that: The double-wall drill bit comprises a drill bit outer cylinder (1), a drill bit inner cylinder (2), a drill bit base (10) and a pick (9); The drill bit outer cylinder (1) is an integrated structure, divided into three parts: upper, middle and lower. The upper and lower parts are straight cylinder structures, and the diameter of the upper cylinder is larger than that of the lower cylinder. The upper surface of the upper cylinder is an open structure, and the center of the lower surface is provided with a hexagonal opening of the same size as the hexagonal joint (5). A plurality of square openings (7) are symmetrically arranged on the upper part of the upper cylinder as a rotating rod joint, so that the rotating rod is installed on the upper cylinder. Two circular openings are also symmetrically arranged on the upper part of the upper cylinder. The impactor is inserted into the double-wall drill bit from the upper cylinder, and the rotating rod and the impactor are connected by the cooperation of the connecting rod and the circular opening. The lower surface of the lower cylinder is an open structure, and the center of the upper surface is provided with a hexagonal opening of the same size as the hexagonal joint (5). A compressed air inlet (6) is provided; the middle portion includes a hexagonal joint (5) and a plurality of wing plates (4); the hexagonal joint (5) is a hexagonal cylinder structure, the upper and lower surfaces of which are respectively connected to the lower surface of the upper cylinder and the upper surface of the lower cylinder; the hexagonal joint (5) is coaxial with the upper cylinder and the lower cylinder; the wing plates (4) are symmetrically arranged on the outside of the hexagonal joint (5); the bottom end of the wing plate (4) is connected to the upper surface of the lower cylinder, the top end is connected to the lower surface of the upper cylinder, and the inner side is connected to the outer wall of the hexagonal joint (5); the impactor is connected to the double-wall drill bit through the hexagonal joint (5), and the air outlet of the impactor is connected to the compressed air inlet (6); The drill base (10) is a circular plate-shaped structure, which is installed at the bottom of the drill outer cylinder (1); the drill inner cylinder (2) is a cylinder with an open bottom, which is located in the lower cylinder of the drill outer cylinder (1); the bottom of the drill inner cylinder (2) is fixedly connected to the inner edge of the drill base (10) as a whole, so that a double-wall drill cavity is formed between the outer wall of the drill inner cylinder (2) and the inner wall of the drill outer cylinder (1), which serves as an air passage (8); The pick teeth (9) are mounted on the drill bit base (10) at equal intervals along the circumferential direction, and a drill bit air outlet hole (3) is opened on the circumference between two adjacent pick teeth (9), and the drill bit air outlet hole (3) is used to blow away rock slag.

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