Pneumatic down-the-hole hammer

Abstract

The present invention relates to the technical field of drilling impactors, and in particular to a pneumatic down-the-hole impactor, comprising a cylinder body, an impact piston and a drill body, and also comprising a spline sleeve attached to the end of the cylinder body, the drill body being matched with the spline sleeve in a manner of passing through the inside of the spline sleeve and forming a spline connection; the pneumatic down-the-hole impactor comprises a bottom-hole slag removal and purge air path, which comprises an internal drill air passage arranged on the drill body, and a transition air passage is formed by means of a spline gap at a spline connection between the drill body and the spline sleeve, so that there is no need or reduction in opening holes on the piston and / or cylinder body, thereby extremely ensuring the structural strength of the piston and / or cylinder body and improving the service life of the impactor as a whole. Moreover, since the transition air passage is formed by means of an existing structure, this also virtually reduces the processing difficulty and manufacturing cost.

Description

Technical Field

[0001] The invention relates to a pneumatic impactor for drilling, in particular to a pneumatic down-the-hole impactor suitable for various types of boreholes for fast drilling of hard rocks. Background Art

[0002] Pneumatic impactor is a relatively efficient hard rock drilling tool. It uses compressed air as the power medium and is widely used for a series of advantages such as high drilling efficiency and good drilling quality.

[0003] During the drilling process of the pneumatic impactor, debris is usually generated at the bottom of the borehole due to the drilling operation. In order to achieve the purpose of blowing and removing debris at the bottom of the hole, the existing pneumatic impactor is usually provided with a bottom-of-hole slag removal blowing air path, so that during the drilling process, the debris at the bottom of the hole can be blown and removed by means of the gas connection path generated by the movement of the piston. However, in order to enable the gas to be introduced into the air channel on the drill bit body, the prior art either opens a corresponding connecting air channel on the piston or opens a corresponding connecting air channel on the side wall of the cylinder body. This practice is very likely to reduce the load strength that the piston and / or cylinder body can withstand. Under high-intensity operation, it is easy for the piston to produce cracks or cracks in the fluid channel, thereby affecting the service life of the piston, and then affecting the service life of the impactor as a whole.

[0004] Based on this, it is necessary to improve the existing pneumatic impactor to overcome the above technical problems. Summary of the invention

[0005] In view of this, the present invention provides a pneumatic down-the-hole impactor, which can form a transition air passage by means of the spline gap at the spline connection between the drill body and the spline sleeve, so that the opening of the piston and / or the cylinder body is unnecessary or reduced, thereby extremely ensuring the structural strength of the piston and / or the cylinder body and improving the service life of the impactor as a whole. Moreover, since the transition air passage is formed by means of the existing structure, this also virtually reduces the processing difficulty and manufacturing cost.

[0006] The invention discloses a pneumatic down-the-hole impactor, comprising a cylinder body of a cylindrical structure, an impact piston and a drill body, wherein the impact piston is arranged in the cylinder body; further comprising a spline sleeve attached to the end of the cylinder body, wherein the drill body cooperates with the spline sleeve in a manner of passing through the inside of the spline sleeve and forming a spline connection; the pneumatic down-the-hole impactor comprises a bottom hole deslagging and blowing air path, which comprises an internal drill air passage arranged on the drill body.

[0007] According to the pneumatic down-the-hole impactor of the present invention, the spline gap at the spline connection between the drill body and the spline sleeve forms a spline transition air channel, the spline transition air channel constitutes a part of the bottom hole slag removal and purge air path, and the air inlet end of the air channel inside the drill bit is connected to the spline transition air channel.

[0008] The so-called spline clearance refers to the gap formed after the outer splines of the drill body and the inner splines of the spline sleeve form a spline fit, and the gap allows gas to pass through. In the impactor, the spline fit between the drill body and the spline sleeve is an existing commonly used connection scheme. In other words, the present invention uses the existing structure of the impactor to form a part of the bottom hole removal and purge air path, so there is no need to open an air duct on the cylinder body and / or piston of the impactor to form the bottom hole removal and purge air path. The scheme adopted by the present invention is unexpected based on the existing structure of the impactor, because in the existing structure of the impactor, the spline fit is used to achieve the fitting connection between the drill body and the spline sleeve, rather than to form a gas passage.

[0009] According to the pneumatic down-the-hole impactor of the present invention, the pneumatic down-the-hole impactor further includes a retaining ring and a limiting bushing, wherein the retaining ring is stuck in the annular groove above the spline section of the drill body and abuts against the top surface of the spline sleeve; the limiting bushing is sleeved on the upper periphery of the drill body, and the lower end of the limiting bushing abuts against the retaining ring, and the upper end abuts against the limiting step provided inside the cylinder body. The bottom hole slag removal and purge air path also includes an upper transition airway and an air path inside the bushing, the upper transition airway is formed by the gap between the limiting bushing and the retaining ring and the upper part of the drill body; the upper transition airway is always connected with the spline gap; the air outlet end of the air path inside the bushing is always connected with the upper transition airway; during the upward movement of the impact piston, the air inlet end of the air path inside the bushing can be connected with the inner cavity of the impact piston, so that part of the gas can enter the bottom hole slag removal and purge air path from the inner cavity of the impact piston to perform bottom hole slag removal.

[0010] That is, in the present invention, the air ducts used to constitute the bottom hole slag removal and purge air circuits are all formed with the aid of existing accessories, and the holes that need to be opened are only the air ducts inside the bushing on the limiting bushing, while the other gaps forming the upper transition air duct and the spline transition air duct are automatically formed by the original accessories of the impactor after being matched.

[0011] Based on the structure of the present invention, the gap between the existing structural parts of the impactor after being matched can be fully utilized to form a bottom hole slag removal and purge air path, thereby greatly reducing the number of air channels opened on the structural parts of the impactor, thereby extremely ensuring the structural strength of the piston and / or cylinder body, and improving the overall service life of the impactor.

[0012] According to the pneumatic down-the-hole impactor of the present invention, a drainage air channel is provided on the lower end of the impact piston, which can be connected with the air inlet end of the air channel in the bushing during the upward movement of the piston.

[0013] In the present invention, the so-called "up" and "down" are relative terms based on the drilling direction of the drill bit body, that is, relatively speaking, the position toward or close to the drilling direction of the drill bit body can be designated as down, and the position away from or away from the drilling direction of the drill bit body can be designated as up.

[0014] According to the pneumatic down-the-hole impactor of the present invention, the lower end of the impact piston is formed as a necked section, which is embedded in the limiting bushing in a tightly fitting manner and abuts against the top of the drill body in an initial state.

[0015] According to the pneumatic down-the-hole impactor of the present invention, the pneumatic down-the-hole impactor also includes an air distribution pipe, which has an attachment portion and a tube body portion. The attachment portion is located above the impact piston and is supported and arranged in the cylinder body in a circumferentially sealed manner; in the cylinder body, an upper air cavity is formed between the top of the impact piston and the attachment portion of the air distribution pipe; in the cylinder body, a lower air cavity is formed between the shoulder of the necked section of the impact piston and the top of the limit bushing.

[0016] According to the pneumatic down-the-hole impactor of the present invention, the interior of the impact piston has an upper gas distribution chamber and a lower gas distribution chamber in the axial direction, the lower end of the tube body of the gas distribution pipe extends into the upper gas distribution chamber, and a first air flow channel that is constantly connected to the upper gas distribution chamber is provided on the extended pipe section, and the lower gas distribution chamber is constantly connected to the lower gas chamber of the impact piston; the impact piston can be driven by the gas medium to perform axial reciprocating movement relative to the gas distribution pipe to perform impact work on the drill bit body; with the aid of the axial reciprocating movement of the impact piston, the upper gas distribution chamber can switch and connect between the lower gas distribution chamber and the upper gas chamber.

[0017] In the present invention, the upper gas distribution chamber and the lower gas distribution chamber are both formed by the inner cavity of the piston, wherein the upper gas distribution chamber is located above the lower gas distribution chamber, and the two can be connected through the inner hole of the radial inner flange of the second piston mentioned below. That is, in the present invention, the upper gas chamber, the upper gas distribution chamber and the lower gas distribution chamber are coaxially arranged, that is, from the overall view of the impactor, the upper gas chamber, the upper gas distribution chamber and the lower gas distribution chamber are arranged in sequence from top to bottom.

[0018] According to the pneumatic down-the-hole impactor of the present invention, an air outlet hole capable of communicating with the upper air chamber is provided on the wall of the cylinder body, and the air outlet hole can be blocked during the rising process of the piston relative to the initial position so that the connection between the upper air chamber and the air outlet hole is cut off; a connecting air passage is provided on the wall of the impact piston to keep the lower air chamber and the lower gas distribution chamber of the impact piston in constant connection.

[0019] According to the pneumatic down-the-hole impactor of the present invention, the impact piston and the gas distribution pipe are cooperatively constructed such that, in an initial state, the gas distribution upper chamber and the upper gas chamber remain disconnected, and the gas distribution upper chamber is connected with the gas distribution lower chamber, so that the gas medium can enter the lower gas chamber, and push the impact piston to produce an axial movement upward relative to the gas distribution pipe; with the help of the upward axial movement of the impact piston relative to the gas distribution pipe, the connection between the gas distribution upper chamber and the gas distribution lower chamber can be disconnected, and the gas distribution upper chamber can be connected with the upper gas chamber, so that the gas medium can enter the upper gas chamber, and then can push the impact piston to produce an axial movement downward relative to the gas distribution pipe.

[0020] The so-called disconnection refers to disconnection of connectivity, that is, there is no connectivity between the two.

[0021] In the present invention, the piston can be driven reciprocally by switching the upper gas distribution chamber between the lower gas distribution chamber and the upper gas chamber, which not only greatly simplifies the gas flow channel structure of the impactor, but also makes it easier to switch the flow channels between the gas flow channels for reciprocating the piston. That is, the flow channel switching and / or the switching of the reciprocating piston drive that require a complex structure in the prior art can be achieved through an extremely simple structure.

[0022] Moreover, more importantly, by configuring an upper gas distribution chamber and a lower gas distribution chamber in the inner cavity of the piston, and allowing the upper gas distribution chamber to switch between the lower gas distribution chamber and the upper gas distribution chamber with the help of the reciprocating movement of the piston, there is no need to arrange a fluid channel on the piston as in the prior art, thereby greatly improving the overall structural strength of the piston and further increasing its service life.

[0023] According to the pneumatic down-the-hole impactor of the present invention, a radially inner flange of the first piston protruding radially inward is provided at a position near the top end in the inner cavity of the impact piston, and a radially outer flange of the first tube body protruding radially outward is provided on the outer side of the tube body portion, and the tube body portion extends into the upper gas distribution cavity after passing through the channel of the radially inner flange of the first piston; in an initial state, the radially inner flange of the first piston and the radially outer flange of the first tube body are in contact with each other and form a tight and / or sealed fit with each other, so that the upper gas distribution cavity and the upper air cavity are kept disconnected; by means of the upward axial movement of the impact piston relative to the gas distribution pipe, the radially inner flange of the first piston can be separated from the contact with the radially outer flange of the first tube body, so that the upper gas distribution cavity and the upper air cavity are connected.

[0024] According to the pneumatic down-the-hole impactor of the present invention, a second piston radial inner flange is arranged between the upper gas distribution chamber and the lower gas distribution chamber in the inner cavity of the impact piston; a second tube body radial outer flange is arranged on the outer side of the tube body below the radial outer flange of the first tube body; in an initial state, the second piston radial inner flange remains disengaged from the second tube body radial outer flange so that the upper gas distribution chamber and the lower gas distribution chamber remain connected; with the help of the upward axial movement of the impact piston relative to the gas distribution pipe, the second piston radial inner flange can form a tight and / or sealed contact fit with the second tube body radial outer flange so that the connection between the upper gas distribution chamber and the lower gas distribution chamber is disconnected.

[0025] In the present invention, the switching connection between the upper gas distribution chamber and the lower gas distribution chamber and the upper gas chamber is achieved by means of a simple flange structure, so there is no need to separately set up an additional reversing valve as in the prior art, thereby greatly simplifying the number of required parts, reducing the complexity of the impactor structure, and further reducing the manufacturing cost.

[0026] Beneficial effects: In the pneumatic down-the-hole impactor of the present invention, the transition air passage is formed by means of the spline gap at the spline connection between the drill body and the spline sleeve, so that the opening of the piston and / or the cylinder body is unnecessary or reduced, thereby extremely ensuring the structural strength of the piston and / or the cylinder body and improving the service life of the impactor as a whole. Moreover, since the transition air passage is formed by means of the existing structure, this also virtually reduces the processing difficulty and manufacturing cost.

[0027] The pneumatic down-the-hole impactor of the present invention is disclosed in detail below with reference to the embodiments shown in the accompanying drawings and the accompanying drawing numbers. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The overall structural diagram of the present invention is shown.

[0029] Reference numerals

[0030] 1 cylinder body, 2 impact piston, 3 distribution pipe, 4 drill body, 5 upper joint, 6 valve body, 7 valve spring, 8 spline sleeve, 9 retaining ring, 10 limit bushing, 11 spline transition air passage, 12 upper transition air passage, 13 bushing inner air passage.

[0031] 101 upper air cavity, 102 lower air cavity, 103 air outlet.

[0032] 201 is an upper gas distribution chamber, 202 is a lower gas distribution chamber, 203 is a radial inner flange of a first piston, 204 is a radial inner flange of a second piston, 205 is a drainage airway, 206 is a necking section, and 207 is a connecting airway.

[0033] 301 attachment portion, 302 pipe body portion, 303 air distribution pipe air inlet passage; 304 air distribution pipe internal passage, 305 first air flow passage, 306 first pipe body radial outer flange, 307 second pipe body radial outer flange.

[0034] 401 drill bit internal air passage.

[0035] 501 connector is the air inlet, 502 connector is the expansion cone channel.

[0036] 901 spline section, 902 annular groove. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0039] Figure 1 The overall structural diagram of the present invention is shown.

[0040] Combination Figure 1 As shown, the present invention discloses a pneumatic down-the-hole impactor, comprising a cylindrical cylinder 1, an impact piston 2, a gas distribution pipe 3 and a drill body 4. In addition, it also includes an upper joint 5, an opening and closing valve, a spline sleeve 8, a retaining ring 9 and a limit bushing 10. The drill body cooperates with the spline sleeve in a manner of passing through the inside of the spline sleeve and forming a spline connection.

[0041] The specific structure is as follows: the lower end of the cylinder body 1 is connected to the spline sleeve 8 through a thread, the spline on the drill body 4 cooperates with the spline groove on the spline sleeve 8, the retaining ring 9 is clamped in the annular groove 902 above the spline section 901 of the drill body 4, and is blocked on the top surface of the spline sleeve 8 to prevent the drill body 4 from falling off the spline sleeve 8. In a preferred embodiment, the retaining ring is a semicircular clamp; the limiting bushing 10 is sleeved on the upper periphery of the drill body 4, and the upper top surface of the limiting bushing 10 presses against the lower end surface of the radial inner flange of the second cylinder body 1 and the lower bottom surface presses on the retaining ring 9 to limit the retaining ring 9. The piston is arranged in the cylinder body 1 through a sliding clearance fit, and can be pushed by gas to move axially back and forth relative to the cylinder body 1 to form impact work on the drill body 4.

[0042] In addition, the distribution pipe 3 has an attachment portion 301 and a pipe body portion 302, the attachment portion 301 is supported and arranged in the cylinder body 1 in a circumferentially sealed manner, and the lower end of the pipe body portion 302 of the distribution pipe 3 extends into the piston. The upper joint 5 has a joint air inlet 501, and the lower part of the upper joint is expanded to form a joint expansion cone channel 502, the upper end of the pipe body portion 302 of the distribution pipe 3 extends into the joint expansion cone channel 502 of the upper joint 5, and the upper part of the pipe body portion 302 of the distribution pipe 3 is provided with an opening and closing valve, the opening and closing valve includes a valve body 6 and a valve spring 7, the valve body 6 and the valve spring 7 are sequentially arranged in the upper part of the pipe body portion 302 of the distribution pipe 3 from top to bottom, the bottom cylinder of the valve body 6 is interference fit and embedded in the valve spring 7, and the top surface of the valve body 6 has a closed state in close contact with the joint expansion cone channel 502, and an open state in which it is separated from the joint expansion cone channel 502.

[0043] In the present invention, an upper air chamber 101 capable of receiving gas medium is formed between the top of the piston and the attachment portion 301 of the gas distribution pipe 3 in the cylinder body 1, and a lower air chamber 102 capable of receiving gas medium is formed on the outer side of the lower portion of the piston in the cylinder body 1; the interior of the piston has an upper gas distribution chamber 201 and a lower gas distribution chamber 202 in the axial direction, the lower end of the pipe body 302 of the gas distribution pipe 3 extends into the upper gas distribution chamber 201 of the piston, and a first air flow channel 305 is provided on the extended pipe section to be constantly connected with the upper gas distribution chamber 201, and the lower gas distribution chamber 202 is constantly connected with the lower gas distribution chamber 102 of the piston. The impact piston 2 is constructed to be able to be pushed by the gas medium to axially reciprocate relative to the gas distribution pipe 3 to perform impact work on the drill bit body 4; by means of the axial reciprocating movement of the impact piston 2, the upper gas distribution chamber 201 can switch between the lower gas distribution chamber 202 and the upper gas chamber 101. The so-called switching connection means that one of the upper gas distribution chamber 201, the lower gas distribution chamber 202 and the upper gas chamber 101 is connected and disconnected from the other; when connected to the other, it is disconnected from the previous one.

[0044] An air outlet hole 103 which can be connected with the upper air chamber is arranged on the wall of the cylinder body. During the rising process of the impact piston relative to the initial position, the air outlet hole 103 can be blocked so that the connection between the upper air chamber and the air outlet hole 103 is cut off; a connecting air channel 207 which keeps the lower air chamber and the lower gas distribution chamber of the impact piston in constant connection is arranged on the wall of the impact piston.

[0045] The specific implementation process of switching the connection in the present invention is: in the initial state, the upper gas distribution chamber 201 and the upper gas chamber 101 remain disconnected, and the upper gas distribution chamber 201 is connected with the lower gas distribution chamber 202, so that the gas medium can enter the lower gas chamber 102, pushing the piston to produce an upward axial movement relative to the gas distribution pipe 3; with the help of the upward axial movement of the piston relative to the gas distribution pipe 3, the connection between the upper gas distribution chamber 201 and the lower gas distribution chamber 202 can be disconnected, and the connection between the upper gas chamber and the air outlet 103 is cut off, while the upper gas distribution chamber 201 can be connected with the upper gas chamber 101, so that the gas medium can enter the upper gas chamber 101, pushing the piston to produce a downward axial movement relative to the gas distribution pipe 3.

[0046] In the present invention, the piston can be driven reciprocally by switching the upper gas distribution chamber 201 between the lower gas distribution chamber 202 and the upper gas chamber 101, which not only greatly simplifies the gas flow channel structure of the impactor, but also makes it easier to switch the flow channels between the gas flow channels for reciprocating the piston. That is, the flow channel switching and / or the switching of the reciprocating piston drive that require a complex structure in the prior art can be achieved through an extremely simple structure.

[0047] Moreover, more importantly, by configuring an upper gas distribution chamber 201 and a lower gas distribution chamber 202 in the inner cavity of the piston, and making the upper gas distribution chamber 201 switch between the lower gas distribution chamber 202 and the upper gas chamber 101 with the help of the reciprocating movement of the piston, there is no need to arrange a fluid channel on the piston as in the prior art, thereby greatly improving the overall structural strength of the piston and further increasing its service life.

[0048] In a preferred embodiment, the switching connection between the upper gas distribution chamber 201 and the lower gas distribution chamber 202 and the upper gas chamber 101 is achieved by the following structure:

[0049] A first piston radial inner flange 203 protruding radially inward is provided at a position near the top end in the inner cavity of the piston, and a first tube body radial outer flange 306 protruding radially outward is provided on the outer side of the tube body 302, and the tube body 302 extends into the upper gas distribution chamber 201 after passing through the channel of the radial inner flange; in the initial state, the first piston radial inner flange 203 and the first tube body radial outer flange 306 are in contact with each other and form a tight and / or sealed fit with each other, so that the upper gas distribution chamber 201 and the upper gas chamber 101 are kept disconnected; by means of the upward axial movement of the piston relative to the gas distribution pipe 3, the first piston radial inner flange 203 can be separated from the contact with the first tube body radial outer flange 306, so that the upper gas distribution chamber 201 and the upper gas chamber 101 are connected.

[0050] In the inner cavity of the piston, a second piston radial inner flange 204 is arranged between the upper gas distribution chamber 201 and the lower gas distribution chamber 202; below the first tube body radial outer flange 306, a second tube body radial outer flange 307 is arranged on the outer side of the tube body portion 302; in the initial state, the second piston radial inner flange 204 and the second tube body radial outer flange 307 remain disengaged, so that the upper gas distribution chamber 201 and the lower gas distribution chamber 202 remain connected; with the help of the upward axial movement of the piston relative to the gas distribution pipe 3, the second piston radial inner flange 204 can form a tight and / or sealed contact fit with the second tube body radial outer flange 307, so that the connection between the upper gas distribution chamber 201 and the lower gas distribution chamber 202 is disconnected.

[0051] Specifically, the axial position of the first air flow channel 305 is located between the first tube radial outer flange 306 and the second tube radial outer flange 307, and the radial cross-sectional outer diameter of the tube section where the first air flow channel 305 is located is smaller than the outer diameters of the first tube radial outer flange 306 and the second tube radial outer flange 307, so that the first air flow channel 305 can maintain constant communication with the upper valve distribution chamber 201 regardless of whether the first tube radial outer flange 306 is in contact with the first piston radial inner flange 203 or the second tube radial outer flange 307 is in contact with the second piston radial inner flange 204.

[0052] Preferably, the outer diameters of the first tube body radial outer flange 306 and the second tube body radial outer flange 307 are equal. Also, preferably, the outer diameter of the tube section of the tube body portion 302 of the gas distribution pipe 3 located in the upper gas cavity 101 is smaller than the outer diameters of the first tube body radial outer flange 306 and the second tube body radial outer flange 307, so that when the piston moves upward until the first piston radial inner flange 203 is separated from the first tube body radial outer flange 306, the gas distribution upper cavity 201 and the upper gas cavity 101 can be connected.

[0053] In addition, the pneumatic down-the-hole impactor of the present invention also includes a bottom hole slag removal and purge air path, which includes a drill bit internal air channel 401 arranged on the drill bit body. Preferably, the spline gap at the spline connection between the drill bit bodies 4 and 8 forms a spline transition air channel 11, and the spline transition air channel 11 constitutes a part of the bottom hole slag removal and purge air path, and the air inlet end of the drill bit internal air channel 401 is connected to the spline transition air channel 11.

[0054] The bottom hole slag removal and purge air path also includes an upper transition airway 12 and a bushing inner airway 13. The upper transition airway 12 is formed by the gap between the limiting bushing and the retaining ring and the upper part of the drill body 4; the upper transition airway 12 is always connected to the spline gap; the gas outlet end of the bushing inner airway 13 is always connected to the upper transition airway 12; during the upward movement of the impact piston, the gas inlet end of the bushing inner airway 13 can be connected to the inner cavity of the impact piston, so that part of the gas can enter the bottom hole slag removal and purge air path from the inner cavity of the impact piston to perform bottom hole slag removal. That is, in the present invention, the airways used to form the bottom hole slag removal and purge air path are all formed with the help of existing accessories, and the only channel that needs to be opened is the bushing inner airway 13 on the limiting bushing, and the other gaps forming the upper transition airway 12 and the spline transition airway 11 are all automatically formed by the original accessories of the impactor after matching.

[0055] The lower end of the impact piston is provided with a drainage air channel 205, which can be connected with the air inlet end of the air channel 13 in the bushing during the upward movement of the piston. Preferably, the lower end of the impact piston is formed as a necking section 206, which is embedded in the limiting bushing 10 in a tightly fitting manner and stops at the top of the drill body 4 in the initial state.

[0056] The working process of the bottom hole slag removal and purge air circuit is as follows: when the impact piston moves upward to a certain stroke, the connection between the upper gas distribution chamber 201 and the lower gas distribution chamber 202 is cut off, and the drainage airway 205 is connected with the airway 13 in the bushing. At this time, the compressed air in the lower gas distribution chamber 202 and the lower air chamber 102 of the impact piston 2 can be discharged to the drill bit internal airway 401 of the drill bit body 4 through the drainage airway 205, the airway 13 in the bushing, the upper transition airway 12, and the spline transition airway 11, and then introduced to the bottom of the borehole to purge the drill cuttings at the bottom of the hole, thereby achieving bottom hole slag removal.

[0057] The overall working principle of the impactor of the present invention is as follows: in the initial state, the air compressor operates, and the compressed air is pressed into the joint air inlet 501 of the upper joint 5, pushing the valve body 6 of the opening and closing valve, entering the internal channel 304 of the distribution pipe through the air distribution pipe air inlet channel 303, and then entering the upper distribution chamber 201 (specifically, the fluid channel gap formed by the distribution pipe 3 and the piston) through the first air flow channel 305 on the distribution pipe 3, and then entering the lower distribution chamber 202 of the piston, and then entering the lower air chamber 102 of the piston through the connecting air channel 207; in the lower air chamber 102, the compressed gas is pressed to push the piston to produce an upward axial movement. When the piston moves upward, the fluid in the upper air chamber 101 can be discharged through the air outlet 103. When the piston moves upward to a certain stroke, the connection between the upper gas distribution chamber 201 and the lower gas distribution chamber 202 is cut off, the connection between the upper gas distribution chamber 201 and the upper gas chamber 101 is opened, and the connection between the upper gas chamber 101 and the air outlet 103 is cut off. At this time, since the upper gas distribution chamber 201 and the lower gas distribution chamber 202 are connected, and the drainage airway 205 is connected with the airway 13 in the bushing, the compressed air in the lower gas distribution chamber and the lower gas chamber of the impact piston can be discharged to the internal airway of the drill bit body 4 through the drainage airway 205, the airway 13 in the bushing, the upper transition airway 12, and the spline transition airway 11. 401, and then introduced to the bottom of the borehole to purge the drill cuttings at the bottom of the hole, thereby achieving bottom hole slag removal; at the same time, since the connection between the upper gas distribution chamber 201 and the upper gas chamber 101 is opened, the compressed air in the gas distribution pipe will enter the upper gas distribution chamber 201 through the first air flow channel 305, and then enter the upper gas chamber 101, and since the connection between the upper gas chamber 101 and the air outlet 103 is cut off, the compressed air will form a pressure in the upper gas chamber 101, and at this time, a pressure difference will be formed between the upper gas chamber 101 and the lower gas chamber 102, and the impact piston will decelerate upward and accelerate downward to impact the top of the drill bit body 4 by means of the pressure difference. Repeat the above process to achieve impact drilling.

[0058] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0059] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0060] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0061] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A pneumatic down-the-hole impactor, comprising a cylinder body (1) of a cylindrical structure, an impact piston (2) and a drill body (4), wherein the impact piston (2) is arranged in the cylinder body (1); further comprising a spline sleeve (8) attached to the end of the cylinder body (1), wherein the drill body (4) cooperates with the spline sleeve (8) in a manner of passing through the inside of the spline sleeve (8) and forming a spline connection; the pneumatic down-the-hole impactor comprises a bottom hole deslagging purge air path, which comprises an internal drill air passage (401) arranged on the drill body (4), It is characterized in that The spline gap at the spline connection between the drill body (4) and the spline sleeve (8) forms a spline transition air passage (11), the spline transition air passage (11) constitutes a part of the bottom hole slag removal and purge air passage, and the air inlet end of the drill internal air passage (401) is connected to the spline transition air passage (11); The pneumatic down-the-hole impactor further comprises an air distribution pipe (3), wherein the air distribution pipe (3) comprises an attachment portion (301) and a pipe body portion (302); an upper air chamber (101) is formed between the top of the impact piston (2) and the attachment portion (301) of the air distribution pipe (3) in the cylinder body (1); the pneumatic down-the-hole impactor further comprises a limiting bushing (10), wherein a lower air chamber (102) is formed between the impact piston (2) and the top of the limiting bushing (10) in the cylinder body (1); The interior of the impact piston (2) has an upper gas distribution chamber (201) and a lower gas distribution chamber (202) in the axial direction, the lower end of the pipe body (302) of the gas distribution pipe (3) extends into the upper gas distribution chamber (201), and the extending pipe section has a first air flow channel (305) which is always connected to the upper gas distribution chamber (201), and the lower gas distribution chamber (202) is always connected to the lower gas chamber (102) of the impact piston (2); The impact piston (2) can be driven by the gas medium to perform axial reciprocating movement relative to the gas distribution pipe (3) to perform impact work on the drill bit body (4); by means of the axial reciprocating movement of the impact piston (2), the gas distribution upper chamber (201) can be switched and connected between the gas distribution lower chamber (202) and the upper gas chamber (101); The impact piston (2) and the gas distribution pipe (3) are structured in cooperation such that, in an initial state, the gas distribution upper chamber (201) and the upper gas chamber (101) are disconnected, and the gas distribution upper chamber (201) and the gas distribution lower chamber (202) are connected, so that a gas medium can enter the lower gas chamber (102) and push the impact piston (2) to generate an axial movement upward relative to the gas distribution pipe (3); by means of the upward axial movement of the impact piston (2) relative to the gas distribution pipe (3), the connection between the gas distribution upper chamber (201) and the gas distribution lower chamber (202) can be disconnected, and the gas distribution upper chamber (201) can be connected to the upper gas chamber (101), so that a gas medium can enter the upper gas chamber (101), and then push the impact piston (2) to generate an axial movement downward relative to the gas distribution pipe (3); An air outlet hole (103) capable of communicating with the upper air chamber (101) is provided on the wall of the cylinder body (1), and the air outlet hole (103) can be blocked during the ascending process of the impact piston (2) relative to the initial position, so that the communication between the upper air chamber (101) and the air outlet hole (103) is cut off; When the impact piston (2) moves upward to a certain stroke, the compressed air in the lower gas distribution chamber (202) and the lower gas chamber (102) of the impact piston (2) can be discharged to the internal gas passage of the drill bit body through the spline transition gas passage (11), and then introduced to the bottom of the drill hole to blow away the drill cuttings at the bottom of the hole, so as to achieve slag removal at the bottom of the hole; at the same time, the compressed air in the gas distribution pipe (3) will enter the upper gas distribution chamber (201) through the first air flow channel (305), and then enter the upper gas chamber (101), and because the connection between the upper gas chamber (101) and the gas outlet (103) is cut off, the compressed air will form a pressure in the upper gas chamber (101).

2. The pneumatic down-the-hole impactor according to claim 1, characterized in that: The pneumatic down-the-hole impactor further comprises a retaining ring (9), wherein the retaining ring (9) is clamped in an annular groove (902) above the spline section (901) of the drill bit body (3) and abuts against the top surface of the spline sleeve (8); The limiting bushing (10) is sleeved on the upper periphery of the drill bit body (3), and the lower end of the limiting bushing (10) abuts against the retaining ring (9), and the upper end abuts against a limiting step provided inside the cylinder body (1); The bottom hole deslagging purge gas circuit also includes: An upper transition air passage (12) is formed by the gap between the limiting bushing (10) and the retaining ring (9) and the upper part of the drill body (3); the upper transition air passage (12) is always connected to the spline gap; An air passage (13) in the bushing, the air outlet end of which is in constant communication with the upper transition air passage (12); During the upward movement of the impact piston (2), the air inlet end of the air passage (13) in the bushing can be connected to the inner cavity of the impact piston (2), so that part of the gas can enter the bottom hole slag removal and purge air path from the inner cavity of the impact piston (2) to perform bottom hole slag removal and purge.

3. The pneumatic down-the-hole impactor according to claim 2, characterized in that: A drainage air channel (205) is provided on the lower end of the impact piston (2), which can be connected with the air inlet end of the air channel (13) in the bushing during the upward movement of the piston.

4. The pneumatic down-the-hole impactor according to claim 3, characterized in that: The lower end of the impact piston (2) is formed as a necked section (206), and the necked section (206) is embedded in the limiting bushing (10) in a tightly fitting manner and abuts against the top of the drill bit body (3) in an initial state.

5. The pneumatic down-the-hole impactor according to claim 4, characterized in that: The attachment portion (301) is located above the impact piston (2) and is supported and arranged in the cylinder body (1) in a manner having a circumferential seal.

6. The pneumatic down-the-hole impactor according to claim 5, characterized in that: A communicating air passage (207) is provided on the wall of the impact piston (2) to keep the lower air chamber (102) and the gas distribution lower chamber (202) of the impact piston (2) in constant communication.

7. The pneumatic down-the-hole impactor according to claim 6, characterized in that: A first piston radial inner flange (203) protruding radially inward is provided at a position near the top end in the inner cavity of the impact piston (2), a first tube body radial outer flange (306) protruding radially outward is provided on the outer side of the tube body (302), and the tube body (302) passes through the channel of the first piston radial inner flange (203) and then extends into the gas distribution upper cavity (201); In the initial state, the radial inner flange (203) of the first piston and the radial outer flange (306) of the first tube body are in contact with each other and form a tight and / or sealed fit with each other, so that the upper gas distribution chamber (201) and the upper gas chamber (101) are disconnected; By means of the upward axial movement of the impact piston (2) relative to the gas distribution pipe (3), the radial inner flange (203) of the first piston can be separated from the radial outer flange (306) of the first tube body, so that the gas distribution upper chamber (201) and the upper air chamber (101) are connected.

8. The pneumatic down-the-hole impactor according to claim 7, characterized in that: In the inner cavity of the impact piston (2), a second piston radial inner flange (204) is provided between the gas distribution upper cavity (201) and the gas distribution lower cavity (202); below the first tube body radial outer flange (306), a second tube body radial outer flange (307) is provided on the outer side of the tube body portion (302); In the initial state, the radial inner flange (204) of the second piston and the radial outer flange (307) of the second tube body remain separated, so that the upper gas distribution chamber (201) and the lower gas distribution chamber (202) remain in communication; By means of the upward axial movement of the impact piston (2) relative to the gas distribution pipe (3), the radial inner flange (204) of the second piston can form a tight and / or sealed contact fit with the radial outer flange (307) of the second tube body, so that the connection between the gas distribution upper chamber (201) and the gas distribution lower chamber (202) is disconnected.

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