Lifting Hammer and Air-Operated DTH Hammer with Air Shut-off

Abstract

The present invention discloses a hammer and a pneumatic down-the-hole hammer with a lifting hammer airtight structure, belonging to the technical field of pneumatic down-the-hole hammers. The present invention includes an impactor and a bit, the bit is slidably connected to the lower end of the impactor, and there is a limiting device for the bit inside the impactor. The bit has two extreme positions of full extension and full retraction. It is characterized in that an air path control device is provided, which disconnects the air supply air path of the impactor when the bit is in the full extension position and connects the air supply air path of the impactor when the bit is in the full retraction position. The present invention solves the special technical problems of the cluster pneumatic down-the-hole hammer when dealing with inclined rocks, half rocks, karst caves and other strata, solves the problem of a large amount of air jet from the non-ringing sub-hammer, prevents the sudden drop of the air pressure of the whole system, and ensures the hitting force of the ringing hammer part on the rock; improves the construction efficiency in special strata, reduces energy consumption waste, and improves safety.

Description

Technical Field

[0001] The invention relates to a pneumatic down-the-hole hammer, belonging to the technical field of down-the-hole hammers. Background Art

[0002] Under current technical conditions, for projects requiring the bearing layer at the bottom of a pile foundation to extend deep into the bedrock or for pile foundations to penetrate below the rock surface, cluster pneumatic down-the-hole hammers are often used to drill into the rock to enhance the pile foundation's bearing capacity. Currently, there are two main configurations of cluster pneumatic down-the-hole hammers: one with a central (usually larger) main hammer surrounded by smaller hammers; the other with all sub-hammers identical. Regardless of the configuration, the cluster hammer is designed using a single hammer from a standard impactor as its basic component.

[0003] In the Chinese patent "An external structure of a special sub-hammer for a cluster-type pneumatic down-the-hole hammer" (ZL202122860649.9) disclosed on December 17, 2021, the inventor improved the external structure of the sub-hammer based on the design characteristics of the cluster hammer, making certain technical contributions to the design of the cluster hammer, but the internal core part of the special sub-hammer, that is, the impactor part, has not changed in structure and function.

[0004] A particular technical problem facing existing cluster hammers is that, while tracking the actual operation of cluster pneumatic down-the-hole hammers, the inventors of this case discovered that many rock formations encounter oblique rock when the hammer head enters the rock, or that half-rock or caves appear during drilling. This situation has a certain, but not significant, impact on the operation of single hammers; however, it has a significant impact on existing cluster hammers. The presence of oblique rock, half-rock, or caves can cause the sub-hammers on one side of the cluster hammer to strike the rock, while the sub-hammers on the other side, not in the rock, may remain suspended in the air due to lack of support under the drill bit. The key problem is that the sub-hammers that do not strike the rock emit a large amount of air, causing the air pressure of the entire system to drop significantly, resulting in the hammers being unable to strike the rock. This situation makes cluster pneumatic down-the-hole hammers very inefficient when dealing with oblique rock, half-rock, caves, and other formations, resulting in significant energy waste and the possibility of the airflow in the hole collapsing, causing in-hole accidents. Therefore, there is an urgent need to address the technical problems unique to cluster hammers and improve existing cluster hammers and sub-hammers. Summary of the Invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a pneumatic down-the-hole hammer with a raised hammer and air-sealed function and a pneumatic down-the-hole hammer, so that each sub-hammer of the cluster hammer can control the air intake and exhaust according to the situation. When there is no support under the drill bit and the sub-hammer is not working, the air path can be automatically cut off, and no air is released or a small amount of air is released, thereby realizing "raised hammer and air-sealed"; and when there is a support under the drill bit, the impactor can automatically enter the working state to realize "bottoming out strike".

[0006] The present invention is achieved through the following technical solution: a hammer-lifting, air-sealed pneumatic down-the-hole hammer, comprising an impactor and a drill bit, the drill bit being slidably connected to the lower end of the impactor, a limit device for the drill bit being provided inside the impactor, the drill bit having two extreme positions of fully extended and fully retracted, and characterized in that an air path control device is provided for disconnecting the air supply path of the impactor when the drill bit is in the fully extended position, and connecting the air supply path of the impactor when the drill bit is in the fully retracted position.

[0007] As an embodiment, the impactor includes an outer cylinder, the upper end of the outer cylinder is connected to the air inlet joint, the interior of the outer cylinder is sequentially installed with an inner cylinder, a piston and the drill bit, the upper end of the inner cylinder is connected to the gas distribution mechanism, the piston is slidably connected to the outer cylinder and the inner cylinder, the upper end of the piston has a piston upper ring surface extending into the inner cylinder, the lower inner wall of the inner cylinder is provided with an inner cylinder air hole, the outer wall of the piston is provided with a piston air guide groove communicating with the inner cylinder air hole, the lower end surface of the piston is in contact with the upper end surface of the drill bit; the air path control device includes the inner cylinder air hole, the piston upper ring surface and the piston air guide groove, when the drill bit is in the fully extended position, the piston upper ring surface seals the inner cylinder air hole to block the air path between the inner cylinder air hole and the piston air guide groove, when the drill bit is in the fully retracted position, the inner cylinder air hole is located below the piston upper ring surface and communicates with the piston air guide groove.

[0008] Furthermore, the inner cylinder air hole is located below the upper ring surface of the piston, and there is a closed stroke section on the axial direction of the piston between the upper ring surface of the piston and the inner cylinder air hole, and there is a drill bit stroke section on the axial direction of the drill bit between the drill bit and the impactor. The stroke of the closed stroke section should ensure that when the drill bit stroke section is extended downward to fully extended, the upper ring surface of the piston can cover the inner cylinder air hole, and when the drill bit stroke section is retracted upward to fully retracted, the upper ring surface of the piston can stagger the inner cylinder air hole.

[0009] Furthermore, the limiting device is a clamping ring, and the drill bit is installed on the lower end of the outer cylinder through the clamping ring and the drill sleeve.

[0010] Furthermore, the valve mechanism includes a check valve, a spring and a valve seat. The valve seat is fixed to the upper end of the inner cylinder, and the check valve is movably connected between the valve seat and the air intake joint through the spring.

[0011] As an embodiment, the air circuit control device includes an electromagnetic valve arranged on the air supply path of the impactor for controlling the on-off of the air supply path, and an induction device for controlling the on-off of the electromagnetic valve is arranged at the two extreme positions of full extension and full retraction of the drill bit.

[0012] A pneumatic down-the-hole hammer adopts any one of the pneumatic down-the-hole hammers with a raised hammer and air-sealed function.

[0013] The beneficial effects of the present invention are as follows: The present invention provides a new pneumatic down-the-hole hammer with the function of "lifting the hammer to cut off air". The sub-hammer of the present invention is divided into two parts: an impactor and a bit. The impactor is a general term for the impact part of the sub-hammer and does not include the bit part. The impactor of the present invention can achieve the function of "lifting the hammer to cut off air and striking when touching the bottom", that is, when the bit leaves the bottom and is suspended, the impactor closes the air passage, making the air passage blocked and saving air energy; when the bit touches the bottom and is in place, the impactor starts to work. The function of striking when touching the bottom is a function that existing sub-hammers all have. Here, it means that when the sub-hammer touches the bottom again after lifting the hammer to cut off air, the sub-hammer can restore its original striking function.

[0014] The present invention solves the problem of a large amount of air jet from the non-ringing sub-hammer, prevents the sudden drop of the air pressure in the whole system, and ensures the force of the ringing part hitting the rock; it solves the special technical problems of the cluster pneumatic down-the-hole hammer when dealing with inclined rocks, half rocks, karst caves and other strata, improves the construction efficiency in special strata, reduces energy consumption waste, and prevents the accident of the hole being blown collapse by the air flow in the hole, improving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below with reference to the drawings and embodiments.

[0016] Figure 1 It is a schematic structural diagram of the present invention in the state of air supply when touching the bottom;

[0017] Figure 2 It is a schematic structural diagram of the present invention in the state of lifting the hammer to cut off air;

[0018] In the figure, 1, air inlet joint; 2, check valve; 3, spring; 4, air distribution seat; 5, inner cylinder; 5-1, inner cylinder air hole; 5-2, closed stroke section; 6, outer cylinder; 7, piston; 7-1, piston air guide groove; 7-2, upper piston ring surface; 8, bushing; 9, snap ring; 10, bit chuck; 11, bit; 11-1, bit stroke section. EMBODIMENTS

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and not intended as any limitation to the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0020] For technologies, methods and equipment known to those skilled in the art, detailed discussions may not be made, but where appropriate, the said technologies, methods and equipment should be regarded as part of the specification.

[0021] The present invention provides a pneumatic down-the-hole hammer with a raised hammer and airtight seal, comprising an impactor and a drill bit 11. The drill bit 11 is slidably connected to the lower end of the impactor. A limit device for the drill bit 11 is located within the impactor. The drill bit 11 has two extreme positions: fully extended and fully retracted. An air path control device is provided for disconnecting the air supply to the impactor when the drill bit 11 is in the fully extended position, and connecting the air supply to the impactor when the drill bit 11 is in the fully retracted position. The present invention creatively refines the technical problems faced by cluster hammers in construction on special inclined strata by transforming them into the problem of determining whether the impactor air path is "open" or "disconnected" by utilizing the drill bit's "suspended" and "bottomed" states. Example

[0022] like Figure 1 - Figure 2 As shown, the impactor includes an outer cylinder 6, the upper end of the outer cylinder 6 is connected to the air inlet joint 1, the inner cylinder 5, the piston 7 and the drill bit 11 are installed in sequence from top to bottom inside the outer cylinder 6, the upper end of the inner cylinder 5 is connected to the gas distribution mechanism, the piston 7 is slidably connected to the outer cylinder 6 and the inner cylinder 5, the upper end of the piston 7 has a piston upper ring surface 7-2 extending into the inner cylinder 5, the lower inner wall of the inner cylinder 5 is provided with an inner cylinder air hole 5-1, and the outer wall of the piston 7 is provided with a piston air guide groove 7-1 communicating with the inner cylinder air hole 5-1. The lower end surface of the piston 7 is in contact with the upper end surface of the drill bit 11; the air path control device includes the inner cylinder air hole 5-1, the piston upper ring surface 7-2 and the piston air guide groove 7-1. When the drill bit 11 is in the fully extended position, the piston upper ring surface 7-2 seals the inner cylinder air hole 5-1 to block the air path between the inner cylinder air hole 5-1 and the piston air guide groove 7-1. When the drill bit 11 is in the fully retracted position, the inner cylinder air hole 5-1 is located below the piston upper ring surface 7-2 and communicates with the piston air guide groove 7-1.

[0023] As an optimization of Example 1, the inner cylinder air hole 5-1 is located below the piston upper ring surface 7-2, and there is an axially closed stroke section 5-2 on the piston 7 between the piston upper ring surface 7-2 and the inner cylinder air hole 5-1. There is an axially drill bit stroke section 11-1 on the drill bit 11 between the drill bit 11 and the impactor. The stroke of the closed stroke section 5-2 should ensure that when the drill bit stroke section 11-1 is extended downward to be fully extended, the piston upper ring surface 7-2 can cover the inner cylinder air hole 5-1, and when the drill bit stroke section 11-1 is retracted upward to be fully retracted, the piston upper ring surface 7-2 can be staggered from the inner cylinder air hole 5-1.

[0024] As an optimization of Example 1, the limiting device is a retaining ring 9 , and the drill bit 11 is installed on the lower end of the outer cylinder 6 through the retaining ring 9 and the drill sleeve 10 .

[0025] As an optimization of Embodiment 1, the gas distribution mechanism includes a check valve 2, a spring 3, and a gas distribution seat 4. The gas distribution seat 4 is fixed to the upper end of the inner cylinder 5, and the check valve 2 is movably connected between the gas distribution seat 4 and the air inlet joint 1 through the spring 3.

[0026] In this embodiment, without major changes to the main components and structure of the original pneumatic down-the-hole hammer, the position of the air holes in the inner cylinder is adjusted, and the length or structure of the upper ring surface of the piston is adjusted so that the upper ring surface of the piston just closes the air holes in the inner cylinder when the piston falls, realizing the airtight function. At the same time, the stroke length of the bit is adjusted to ensure that when there is no support under the bit (the bit is suspended), the bottom of the piston falls to the upper end surface of the bit, closing the air holes in the inner cylinder; when the bit touches the bottom and lifts up, the piston is lifted, and the upper ring surface of the piston leaves the air holes in the inner cylinder, and the air holes in the inner cylinder resume the ventilation function.

[0027] The working principle of this embodiment is: Figure 1 This is the working state of the sub-hammer when the invention touches the bottom and ventilates. There is support at the bottom of the bit 11, and the bit is at the highest point of the stroke; the bit stroke section 11-1 is above the snap ring 9; at this time, the bottom surface of the piston 7 is in contact with the upper end surface of the bit, and the upper ring surface 7-2 of the piston is higher than the inner cylinder air hole 5-1 of the inner cylinder 5. The inner cylinder air hole 5-1 is communicated with the piston air guide groove 7-1, and all air paths are unblocked, and the impactor works the same as an ordinary sub-hammer.

[0028] When there is no support under the bit, the bit falls to the lowest point under the action of gravity, and the sub-hammer transforms into Figure 2 a state, that is, the "lifting hammer airtight" state. At this time, the bit 11 is at the lowest point of the stroke; the bit stroke section 11-1 has turned to between the bit and the sticking sleeve 10; at this time, the bottom surface of the piston 7 is in contact with the top surface of the bit, and the upper ring surface 7-2 of the piston just blocks the inner cylinder air hole 5-1, and the inner cylinder air hole 5-1 is not communicated with the piston air guide groove 7-1, and the air path is blocked by the upper ring surface 7-2 of the piston, achieving the purpose of "airtight".

[0029] When the sub-hammer is lowered to the bottom of the hole and the bit is lifted upward after there is support at the bottom of the bit, the sub-hammer returns to Figure 1 a state, resumes the striking work, and realizes "striking when touching the bottom". Embodiment

[0030] The gas path control device includes a solenoid valve for controlling the on / off of the gas supply path provided on the gas supply path of the impactor, and an induction device for controlling the on / off of the solenoid valve is provided at two extreme positions of the full extension and full retraction of the bit 11. The induction device can be various sensors, travel switches, etc. By measuring the position of the bit and determining the on / off of the solenoid valve according to the signal of the induction device, the ventilation and airtight functions are realized.

[0031] A pneumatic down-the-hole hammer adopts the sub-hammer of the lifting hammer airtight type pneumatic down-the-hole hammer in Embodiment 1 or Embodiment 2.

[0032] In Embodiment 1, the position of the bit is used to push the piston of the impactor to two different positions, and these two positions are exactly designed to be the "venting" and "airtight" states of the inner cylinder air holes. The sub-hammer impactor needs to be redesigned. In Embodiment 2, the existing sub-hammer can be directly used, and only the circuit and air circuit are added to the periphery. The impactors of the two types of embodiments of the present invention can both achieve the functions of "lifting the hammer to close the air and hitting the bottom when touching the bottom", that is, when the bit leaves the bottom surface and is suspended, the impactor closes the air circuit to make the air circuit blocked, saving air energy; when the bit touches the bottom surface and is in place, the impactor starts to work. The function of hitting the bottom when touching the bottom is a function that existing sub-hammers all have. Here, it means that when the sub-hammer touches the bottom again after lifting the hammer to close the air, the sub-hammer can restore its original hitting function.

[0033] The above are only exemplary embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A pneumatic down-the-hole hammer with a hammer lifting and airtight function, comprising a percussion drill and a bit (11), the bit (11) is slidably connected to the lower end of the percussion drill, and there is a limiting device for the bit (11) inside the percussion drill. The bit (11) has two extreme positions: fully extended and fully retracted. It is characterized in that: An air path control device is provided for disconnecting the air path of the impactor when the drill bit (11) is in a fully extended position and connecting the air path of the impactor when the drill bit (11) is in a fully retracted position; The impactor comprises an outer cylinder (6), the upper end of the outer cylinder (6) is connected to the air inlet joint (1), the inner cylinder (5), the piston (7) and the drill bit (11) are sequentially installed inside the outer cylinder (6) from top to bottom, the upper end of the inner cylinder (5) is connected to the gas distribution mechanism, the piston (7) is slidably connected to the outer cylinder (6) and the inner cylinder (5), the upper end of the piston (7) has a piston upper ring surface (7-2) extending into the inner cylinder (5), the lower inner wall of the inner cylinder (5) is provided with an inner cylinder air hole (5-1), and the outer wall of the piston (7) is provided with a piston air guide groove (7-1) communicating with the inner cylinder air hole (5-1). ), the lower end surface of the piston (7) contacts the upper end surface of the drill bit (11); the air path control device includes the inner cylinder air hole (5-1), the piston upper ring surface (7-2) and the piston air guide groove (7-1); when the drill bit (11) is in the fully extended position, the piston upper ring surface (7-2) seals the inner cylinder air hole (5-1) to block the air path between the inner cylinder air hole (5-1) and the piston air guide groove (7-1); when the drill bit (11) is in the fully retracted position, the inner cylinder air hole (5-1) is located below the piston upper ring surface (7-2) and communicates with the piston air guide groove (7-1); The inner cylinder air hole (5-1) is located below the piston upper ring surface (7-2), and the piston (7) between the piston upper ring surface (7-2) and the inner cylinder air hole (5-1) has a closed stroke section (5-2) in the axial direction, and the drill bit (11) between the drill bit (11) and the impactor has a drill bit stroke section (11-1) in the axial direction. The stroke of the closed stroke section (5-2) should ensure that when the drill bit stroke section (11-1) is extended downward to be fully extended, the piston upper ring surface (7-2) can cover the inner cylinder air hole (5-1), and when the drill bit stroke section (11-1) is retracted upward to be fully retracted, the piston upper ring surface (7-2) can stagger the inner cylinder air hole (5-1).

2. The pneumatic down-the-hole hammer with a lifting hammer and air shut-off according to claim 1, wherein: The limiting device is a clamping ring (9), and the drill bit (11) is installed on the lower end of the outer cylinder (6) through the clamping ring (9) and the clamping sleeve (10).

3. The hammer of the lifting hammer airtight pneumatic down-the-hole hammer according to claim 1, characterized in that: The gas distribution mechanism comprises a check valve (2), a spring (3) and a gas distribution seat (4); the gas distribution seat (4) is fixed to the upper end of the inner cylinder (5); and the check valve (2) is movably connected between the gas distribution seat (4) and the air inlet joint (1) via the spring (3).

4. The hammer of the lift-hammer airtight pneumatic down-the-hole hammer according to claim 1, characterized in that: The air circuit control device comprises an electromagnetic valve provided on the air supply circuit of the impactor for controlling the on-off of the air supply circuit, and an induction device for controlling the on-off of the electromagnetic valve is provided at the two extreme positions of the drill bit (11) of full extension and full retraction.

5. A pneumatic down-the-hole hammer, comprising the hammer-lifting, air-sealing pneumatic down-the-hole hammer according to any one of claims 1 to 4.

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