Impact hole forming device of a self-closing airway punch pile driver and its operation method

Abstract

This invention discloses an impact drilling device for a percussion pile driver with self-closing air channels, comprising a suspended gantry, a pile hammer, a first rotary joint, a hose, and valves. The top of the suspended gantry has a lifting hole, and the bottom of the suspended gantry is rotatably connected to the top of the pile hammer via a turntable bearing. The pile hammer has multiple air channels inside. The first rotary joint includes a fixed sleeve and a rotating mandrel. The inner cavity of the rotating mandrel communicates with each air channel. One end of the hose is connected to the fixed sleeve, and the other end is used to connect to an air compressor on the ground. A valve is installed at the lower end of each air channel. When the air compressor supplies air to the hose, the airflow opens the valve and sprays out of the air channel. When the air compressor stops supplying air, the valve automatically closes to prevent drill cuttings from clogging the air channels. This invention effectively prevents hose entanglement caused by the pile hammer's rotation, and the valves automatically close when air supply stops, effectively preventing drill cuttings backflow and air channel blockage.

Description

Technical Field

[0001] This invention belongs to the field of percussion pile drivers, and more specifically, relates to an impact hole-forming device for a percussion pile driver with a self-closing air passage and its operating method. Background Technology

[0002] In the field of percussion pile driving and in pile foundation construction for building foundations, percussion pile driving machines are a widely used conventional drilling equipment. Traditional percussion drilling typically involves suspending a heavy pile hammer with a steel cable, and relying on a winch to drive the hammer in a reciprocating motion inside the pile hole. The hammer's immense gravitational potential energy impacts the hard rock layer at the bottom of the hole, causing it to fracture. After the rock is broken, the flow and buoyancy of the drilling mud suspend the drill cuttings, such as gravel and sand, at the bottom of the hole, carrying them to the surface for discharge.

[0003] However, with the increasing depth of construction operations and the rise in large-diameter pile foundation projects, the traditional method of relying solely on mud circulation for cuttings removal has revealed serious limitations. In deep-hole operations, the flow rate and carrying capacity of the mud decrease significantly, causing large particles of gravel and high-density sediment to remain and deposit at the bottom of the borehole instead of rising quickly. This deposited drill cuttings form a thick buffer layer at the bottom of the hole. When the pile hammer falls again, most of the impact kinetic energy is absorbed by this layer, significantly reducing the energy actually transferred to the unbroken bedrock below. This results in a significant decrease in drilling efficiency and exacerbates wear on the bottom of the pile hammer.

[0004] To improve this situation, the industry has begun to experiment with introducing high-pressure gas inside the pile hammer to assist in slag removal. Existing auxiliary slag-blowing pile hammers typically have ventilation holes inside the hammer that extend to the bottom of the hole. Compressed air from the ground is introduced to the bottom of the hole through a high-pressure hose connected to the top. The high-pressure gas expands and releases at the bottom of the hole, disturbing the sediment and mixing with the mud to form a three-phase flow of gas, liquid, and solid, thereby accelerating the slag removal speed.

[0005] Due to the immense hydrostatic pressure within the borehole, primarily generated by the high-density mud column, the air pressure inside the air duct drops rapidly when the pile hammer is being lifted or the surface air compressor stops supplying air. At this time, the high-pressure mud from the bottom of the borehole, carrying a large amount of sharp gravel and hard rock fragments, instantly floods into the open air duct. This solid-liquid mixture of viscous mud and sharp gravel easily accumulates, compresses, and settles within the narrow passage. Because of the complex borehole environment and the continuous accumulation of drill cuttings, the high-pressure airflow during the next air supply often fails to dislodge the compacted mud-rock mixture. Construction workers are forced to stop work and manually clear the borehole of the pile hammer, which weighs tens of tons. This not only consumes a significant amount of time and manpower but also severely slows down the overall construction progress and increases the project's additional costs.

[0006] Furthermore, the impact drilling device of a percussion pile driver is connected via a flexible steel cable during suspended operation. When subjected to immense tension, the steel cable generates torsional stress. When the pile hammer impacts the rock strata at the bottom of the hole or is lifted and suspended, the stress release in the steel cable causes the pile hammer below to rotate uncontrollably and irregularly. In existing slag-blowing pile hammers, the high-pressure air supply hose is often directly and rigidly connected to the top of the pile hammer using a standard fixed connector. This forces the hose to rotate along with the pile hammer as it rotates within the hole. Over time, the hose gradually becomes entangled in the steel cable. Excessive twisting of the hose drastically reduces its internal cross-sectional area, hindering the normal flow of high-pressure gas and resulting in insufficient air supply to the bottom of the hole. In severe cases, prolonged twisting and pulling can create significant stress concentration on the hose surface, eventually causing the high-pressure hose to burst or break within the hole, leading to a failure of the air supply system and posing a high-risk safety hazard. Summary of the Invention

[0007] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides an impact hole forming device and its operation method for a punching pile driver with a self-closing air passage. The coaxial first rotary joint effectively prevents the hose from getting tangled due to the rotation of the pile hammer, and the self-closing valve at the bottom of the air passage realizes automatic closure when the air is stopped, thereby effectively avoiding the backflow of drilling cuttings and blockage of the air passage.

[0008] To achieve the above objectives, according to one aspect of the present invention, an impact drilling device for a self-closing air passage percussion pile driver is provided, comprising a suspension gantry, a pile hammer, a first rotary joint, a hose, and a valve, wherein: The top of the suspension gantry is provided with a lifting hole for connecting steel ropes. The bottom of the suspension gantry is rotatably connected to the top of the pile hammer through a turntable bearing, so that the pile hammer has a vertical rotation center line when suspended. The outer ring of the turntable bearing is fixedly connected to the suspension gantry by bolts, and the inner ring of the turntable bearing is fixedly connected to the pile hammer by bolts. The pile hammer has multiple air channels inside, and the lower end of each air channel extends to the bottom of the pile hammer. The rotation center line of the first rotary joint is coaxial with the center line of the turntable bearing. The first rotary joint includes a fixed sleeve and a rotating mandrel that are rotatably fitted. The fixed sleeve is fixedly connected to the suspension gantry through a rigid connector. The rotating mandrel is fixedly connected to the pile hammer, and the inner cavity of the rotating mandrel is connected to each of the air passages respectively. One end of the hose is connected to the fixed sleeve, and the other end of the hose is used to connect to the air compressor on the ground; Each of the air passages is provided with a valve at its lower end, so that when the air compressor supplies air into the hose, the airflow opens the valve and sprays out of the air passage, and when the air compressor stops supplying air, the valve automatically closes to prevent drill cuttings from passing through the valve and causing blockage in the air passage.

[0009] Preferably, the lower end of each air passage is provided with a cylindrical mounting hole, and a valve is embedded in each cylindrical mounting hole. Furthermore, a limiting ring is provided at the opening of the cylindrical mounting hole to prevent the valve from falling downward.

[0010] Preferably, the openings of the cylindrical mounting holes are evenly distributed circumferentially on the bottom surface of the pile hammer; The centerline of each cylindrical mounting hole is inclined relative to the horizontal plane. The horizontal projection lines of the centerlines of all cylindrical mounting holes are distributed on the side of a regular polygon on the same horizontal plane, and there is a gap between any two adjacent horizontal projection lines. The bottom of the pile hammer is also provided with a spiral guide groove corresponding to the opening of each of the cylindrical mounting holes. Each spiral guide groove starts from the opening of the corresponding cylindrical mounting hole, extends outward in an Archimedean spiral shape and penetrates to the outer wall of the pile hammer, so as to form a vortex at the bottom of the pile hammer, thereby discharging the drill cuttings along the spiral guide groove.

[0011] Preferably, the lower end of the rotating mandrel is integrally formed with a flange, and the flange is fixedly connected to the pile hammer by bolts.

[0012] Preferably, a confluence air chamber is formed inside the pile hammer near the top, and the rotating mandrel is connected to each of the air passages through the confluence air chamber; The manifold chamber is laterally provided with a porous buffer baffle, which divides the manifold chamber into an upper jet buffer chamber and a lower pressure stabilizing and diverting chamber. The porous buffer plate is provided with multiple throttling buffer holes; Multiple air passages are evenly spaced along the inner circumference of the pile hammer, and the upper end of each air passage is connected to the pressure stabilizing and diverting cavity.

[0013] Preferably, the bottom of the pile hammer has a plurality of protruding carbide teeth for crushing rock, and these protruding carbide teeth form a chip removal channel at the bottom of the pile hammer. The orifice at the lower end of each of the air passages is located at the bottom of the chip removal channel to prevent the valve from colliding with and being damaged by the rock layer when the pile hammer falls and impacts the rock layer.

[0014] Preferably, at least one slag discharge guide channel is provided on the outer side wall of the pile hammer along the axial or spiral direction. The slag discharge guide channel extends upward from the bottom of the pile hammer and penetrates to the top end face of the pile hammer so that the drill cuttings are discharged upward along the slag discharge guide channel.

[0015] Preferably, it further includes a tension-following winding and unwinding device, which includes a support frame, a winding and unwinding drum, a second rotary joint, and a torque limiter. The support frame is set on the ground, the take-up and undo drum is rotatably mounted on the support frame, and the hose is wound around the take-up and undo drum; The second rotary joint is located at the rotation axis of the winding and unwinding drum. The fixed end of the second rotary joint is connected to the air compressor pipeline on the ground, and the rotating end of the second rotary joint is connected to the end of the hose away from the first rotary joint. The torque limiter is connected to the central shaft of the take-up and undo drum.

[0016] Preferably, the bottom end of the valve is higher than the orifice at the bottom of the air passage, and a wear-resistant alloy coating is provided on the inner wall of the air passage. The wear-resistant alloy coating is located below the valve and extends to the orifice at the bottom of the air passage.

[0017] According to another aspect of the invention, a method of operation based on the aforementioned impact drilling apparatus is also provided, comprising the following steps: 1) Suspend the pile hammer on the steel rope of the drilling pile driver, connect one end of the hose to the fixing sleeve of the first rotary joint, and connect the other end of the hose to the air compressor on the ground through a two-position three-way valve; 2) The pile hammer falls to impact the bottom of the hole. At the same time as the pile hammer contacts the bottom of the hole, the two-position three-way valve is controlled to connect the air passage, so that the airflow output by the air compressor is sprayed out from the hole opening through the hose and the air passage to blow up the drill cuttings at the bottom of the hole, thereby causing the drill cuttings to rise along the hole wall with the mud and be discharged from the hole opening. 3) The drilling and piling machine drives the pile hammer to lift. At the same time as lifting, the two-position three-way valve is controlled to switch the state to cut off the air passage to the hose and unload and empty the airflow output by the air compressor, thereby pausing the air supply to the hose. At this time, the valve automatically closes. 4) Repeat steps 2) and 3) until the depth of the pile hole reaches the design requirements; during this cycle, the air compressor always keeps supplying air to the two-position three-way valve.

[0018] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: 1) The impact drilling device of the self-closing air passage percussion pile driver of the present invention, by setting a first rotary joint, and the rotation center line of the first rotary joint is coaxially arranged with the center line of the turntable bearing, so that when the pile hammer rotates, the fixed sleeve in the first rotary joint and the hose remain relatively stationary, while the rotating spindle rotates synchronously with the pile hammer. This coaxial decoupling design effectively avoids the twisting and pulling of the hose in the hole, reduces surface stress concentration, and significantly reduces the safety hazard of high-pressure hose rupture.

[0019] 2) The impact drilling device of the self-closing air duct percussion pile driver of the present invention is equipped with a one-way valve at the lower end of each air duct. When the air compressor supplies air, the airflow can smoothly open the valve to spray out the slag, and when the air supply stops, the valve will automatically close. This effectively prevents mud and drill cuttings from entering the air duct, avoids the squeezing and compaction of solid-liquid mixture in the narrow pipe, eliminates the tedious process of frequently lifting the hammer to clear the blockage, and effectively ensures the overall construction progress.

[0020] 3) The impact drilling device of the self-closing air-channel percussion pile driver of the present invention employs multiple air channels, which improves the uniformity of slag removal from the bottom of the hole. Multiple through-channels are provided inside the pile hammer, enabling the high-pressure gas to be dispersed and guided to multiple locations at the bottom of the hammer. Compared to a single air channel, this design provides a wider flow field coverage. Combined with the opening and closing of valves, this helps to more efficiently blow up the drill cuttings from the bottom of the hole and discharge them with the rising mud, improving the overall performance of auxiliary slag removal. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating the operation of the present invention; Figure 2 This is a schematic diagram showing the connection between the turntable bearing and the suspension frame on the pile hammer of the present invention; Figure 3 This is a schematic diagram showing the projection of the center lines of the cylindrical mounting holes of all air passages in this invention onto the same horizontal plane. Figure 4 This is a schematic diagram showing the relative positions of the support frame, the take-up and undo drum, and the second rotary joint of the tension-following take-up and undo device in this invention. In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1. Pile hammer; 2. Turntable bearing; 3. First rotary joint; 4. Hoses; 5. Valves; 10. Air passages; 11. Cylindrical mounting holes; 111. Horizontal projection lines; 12. Suspension gantry; 13. Combination air chamber; 14. Porous buffer plate; 15. Carbide teeth; 16. Chip removal channel; 6. Support frame; 61. Winding drum; 611. Central shaft; 62. Second rotary joint; 100. Pile hole; 200. Air compressor; 300. Piling machine; 301. Steel rope. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0023] Reference Figures 1-4 The impact drilling device of a self-closing air duct percussion pile driver includes a suspension gantry 12, a pile hammer 1, a first rotary joint 3, a hose 4, and a valve 5, wherein: The top of the suspension gantry 12 is provided with a lifting hole for connecting the steel rope 301. The bottom of the suspension gantry 12 is rotatably connected to the top of the pile hammer 1 through a turntable bearing 2, so that the pile hammer 1 has a vertical rotation center line when suspended. Bolt holes are provided on the outer and inner rings of the turntable bearing 2 respectively. The outer ring of the turntable bearing 2 is fixedly connected to the suspension gantry 12 by bolts, and the inner ring of the turntable bearing 2 is fixedly connected to the pile hammer 1 by bolts. The pile hammer 1 has multiple air passages 10 inside, and the lower end of each air passage 10 extends to the bottom of the pile hammer 1. The rotation center line of the first rotary joint 3 is coaxial with the center line of the turntable bearing 2. The first rotary joint 3 includes a fixed sleeve and a rotating spindle that are rotatably fitted. The fixed sleeve is fixedly connected to the suspension gantry through a rigid connector, so that the fixed sleeve is less affected by the rotation of the rotating spindle. The rotating spindle is fixedly connected to the pile hammer 1, and the inner cavity of the rotating spindle is connected to each of the air passages 10 respectively. One end of the hose 4 is connected to the fixed sleeve, and the other end of the hose 4 is used to connect to the air compressor 200 on the ground; The inner ring of the turntable bearing 2 can surround the first rotary joint 3, that is, the first rotary joint 3 can pass through the inner ring of the turntable bearing 2 as a whole. The upper end of the first rotary joint 3 is the upper end of the fixed sleeve, and the lower end of the first rotary joint 3 is the lower end of the rotating spindle. The upper end of the fixed sleeve extends beyond the upper end of the inner ring of the turntable bearing 2. The pile hammer 1 is provided with a groove at the position corresponding to the first rotary joint 3. The lower end of the rotating spindle is fixedly connected to the bottom of the groove. The rotating spindle can be directly connected to each air passage. Alternatively, the pile hammer 1 has an upwardly extending hollow cylinder, the inner cavity of which is connected to each air passage 10. The upper end of the hollow cylinder extends beyond the inner ring of the turntable bearing 2 and is fixedly connected to the lower end of the rotating spindle. There is a gap or interference fit between the hollow cylinder and the inner ring of the turntable bearing 2, and the rotating spindle is connected to the hollow cylinder.

[0024] Each of the air passages 10 is provided with a valve 5 at its lower end, so that when the air compressor 200 supplies air to the hose 4, the airflow opens the valve 5 and sprays out of the air passage 10, and when the air compressor 200 stops supplying air, the valve 5 automatically closes to prevent drill cuttings from causing blockage in the air passage 10 after passing through the valve 5.

[0025] In drilling operations, the equipment needs to withstand frequent and high-intensity gravity lifting and impact feedback. The suspension gantry 12 bears the upward lifting load, while the turntable bearing 2 forms a reliable pivot node. Through the introduction of the turntable bearing 2, the structure, while bearing enormous axial tensile force, releases circumferential rotational freedom. This allows the pile hammer 1 to smoothly rotate around the vertical rotation centerline when it encounters complex geological reaction forces at the bottom of the hole and experiences a tendency to rotate. This rotational decoupling design prevents torsional stress from being transmitted upwards along the suspension gantry 12, protecting the connected cables or wire ropes from torsional fatigue damage.

[0026] Meanwhile, the use of bolts for fixing provides a strong and uniform pre-tightening clamping force for the structure. The contact surfaces between the outer ring and the suspension gantry 12, and between the inner ring and the pile hammer 1, form a high-strength rigid fit under the tightening of the bolts. This large-area flange-type fixing method effectively resists the severe longitudinal vibration and lateral jump generated by the pile hammer 1 when repeatedly impacting the rock strata, preventing loosening, slippage, or tearing of the connection nodes, and ensuring the structural stability of the overall suspension system under harsh working conditions. Furthermore, the outer ring and the inner ring respectively bear the stationary end and the rotating end, making the transmission paths of gravity load and rotational kinetic energy clearly distinct, maintaining the long-term accurate positioning of the vertical rotation center line, and helping to improve the verticality and hole formation quality of the pile hole 100.

[0027] This invention employs a multi-parallel gas channel design, overcoming the uneven flow field distribution that is easily caused by a single gas supply point. Multiple gas channels 10 can disperse and guide the high-pressure gas supplied from above to various areas at the bottom of the pile hammer 1, forming a broad and uniform fluid disturbance field at the bottom of the hole. The uniformly distributed airflow, when ejected from the bottom, can cover a wider area of ​​the hole bottom, promoting the synchronous lifting of a large amount of drill cuttings. Furthermore, the multiple gas channels 10 inside the pile hammer 1 body maintain the symmetry of the overall mass distribution of the pile hammer 1. This symmetrical mass distribution corresponds to the vertical rotation centerline, preventing tilting and flow deviation of the pile hammer 1 during free fall due to a shift in the center of gravity, ensuring the concentrated release of impact kinetic energy and the stability of the equipment's posture.

[0028] Since the first rotary joint 3 and the turntable bearing 2 are coaxially arranged and both operate around the vertical rotation center line, they maintain a high degree of consistency in their operating trajectories. The huge impact load and radial sway caused by the heavy pile hammer 1 are mainly borne and dissipated by the robust turntable bearing 2, thereby creating a stable and low-vibration working microenvironment for the first rotary joint 3 inside.

[0029] The fixed sleeve in the first rotary joint 3 remains in a non-rotating state, while the rotating mandrel rotates synchronously with the pile hammer 1. The rotational cooperation between the two is smooth and unobstructed, reducing the probability of eccentric compression deformation of the internal sealing components and extending the service life of the airway rotary joint 3. In addition, the inner cavity of the rotating mandrel is connected to each of the air passages 10, forming a smooth and unobstructed fluid convergence and distribution path with low pressure loss, ensuring efficient transfer and pressure equalization of airflow energy during the diversion process.

[0030] Because the fixed sleeve is constrained during operation and does not rotate with the pile hammer 1, the connected hose 4 can always maintain a relatively static, vertically suspended posture. This feature effectively prevents the hose 4 from tangling, knotting, or twisting due to the rotation of the pile hammer 1 in deep hole environments. The hose 4 is protected from torsional stress, preventing structural cracking of the pipe wall material due to excessive tension and ensuring that the flow cross-sectional area inside the hose 4 does not shrink due to twisting. The constant and spacious hose 4 channel allows the high-pressure gas output from the air compressor 200 to be continuously delivered to the fixed sleeve at a stable flow rate and velocity, ensuring a continuous gas supply for the bottom-hole slag removal operation and significantly improving the reliability and durability of the equipment's air supply system.

[0031] During the active slag removal phase, the air compressor 200 continuously pumps in high-pressure gas, establishing a strong positive air pressure inside the pipeline. This positive air pressure acts directly on the valve 5, overcoming the hydrostatic pressure of the high-density drilling mud deep at the bottom of the hole, and smoothly pushing the valve 5 open. The high-pressure airflow then sprays out of the air passage 10, forming a powerful jet that forcefully blows up the deposited drill cuttings, reducing the local density of the mixed fluid, promoting the discharge of a large amount of drill cuttings out of the hole, and significantly improving the cuttings removal rate of the drilling operation.

[0032] During work breaks or routine hammer lifting when air supply is interrupted (i.e., when the air compressor 200 stops supplying air), the positive drive air pressure inside the pipeline drops rapidly. At this time, the high-density mud and cuttings mixture at the bottom of the hole will experience a strong inward squeezing tendency under the enormous hydrostatic pressure. Thanks to this feedback feature, the valve 5 can quickly and automatically close. After closing, the valve 5 forms a robust protective barrier at the lower end of each air passage 10, precisely blocking external fluids. This mechanism effectively prevents drilling cuttings containing a large number of hard particles from flowing back in after passing through the valve 5, avoiding the accumulation and compaction of mud and gravel in the narrow air passage 10 cavity, which can lead to difficult-to-clear blockages. Since the inside of the air passage 10 remains clean, the airflow can be instantly unobstructed when the air supply is restarted, eliminating the need for construction personnel to frequently lift heavy equipment out of the hole for manual clearing, shortening ineffective working time, and improving the continuous advancement efficiency of the overall drilling operation.

[0033] During the hammer lifting and free fall impact phases, the suspension gantry 12 bears the tension from the lifting hole of the drilling pile driver 300. The bolts are tightly fitted with the outer and inner rings to ensure the connection does not slip. If the pile hammer 1 rotates due to stress release, the fixed sleeve remains stationary, leaving the hose 4 in a stress-free relaxed state. At the moment of impact, the kinetic energy at the bottom of the pile hammer 1 is released violently, and a strong recoil load is transmitted along the vertical rotation center line, preventing eccentric torque from damaging the components. The rotating mandrel fixedly connected to the pile hammer 1 resists shock waves through a stable assembly relationship, ensuring a constant operating clearance between it and the fixed sleeve. During the high-pressure blowing phase, the gas from the air compressor 200 flows smoothly through the stationary hose 4, passes through the rotating interface, enters the inner cavity of the rotating mandrel, and then splits into multiple air channels 10, finally opening the valve 5 and directly converting the airflow power into a strong flow field to remove drill cuttings. During shutdown, the automatic closing feedback action of valve 5 provides reliable anti-backflow protection for this cycle. The impact drilling device of the entire self-closing air passage 10 of the percussion pile driver 300 improves the operational stability of the equipment under harsh working conditions and significantly optimizes the fluid cleaning efficiency and continuous drilling performance in deep hole construction operations.

[0034] In some embodiments, the lower end of each air passage 10 is provided with a cylindrical mounting hole 11, and a valve 5 is respectively embedded in each cylindrical mounting hole 11. Preferably, the valve 5 is embedded by means of threaded connection or interference fit, and a limiting ring is also provided at the opening of the cylindrical mounting hole 11 to prevent the valve 5 from falling downward.

[0035] The cylindrical mounting hole 11 provides a regular and symmetrical internal space for the valve 5. The cylindrical internal structure has good geometric consistency and smoothness, ensuring a uniform stress distribution around the installation area when the valve 5 is installed, preventing localized stress concentration. This uniform stress distribution helps to smoothly disperse the impact load transferred from the bottom rock layer to the pile hammer 1 during high-frequency impact operations of the percussion drilling device, thus ensuring the structural stability of the material surrounding the mounting hole. Simultaneously, the smooth transition of the inner wall of the cylindrical mounting hole 11 reduces structural weak points caused by abrupt changes in cross-section, improving the overall compressive strength and structural stiffness of the pile hammer 1 at the hole opening.

[0036] The design of embedding one valve 5 in each of the cylindrical mounting holes 11 enables independent opening and closing control of multiple air passages 10 at the fluid end. Each valve 5 occupies an independent cylindrical mounting hole 11, ensuring that the working states of each valve 5 do not interfere with each other. When the air compressor 200 supplies air to the hose 4, the airflow distributed in different air passages 10 opens their respective valves 5, forming multiple and independent fluid injection points on the bottom surface of the pile hammer. This independent embedding method gives each air passage 10 a strong autonomous operating capability when performing slag removal operations. Even if the external mud pressure fluctuates at a certain point, each valve 5 can still operate independently based on its own structure, ensuring a balanced and stable overall flow field distribution at the bottom of the pile hammer and improving the coordinated operation level of the exhaust and slag removal system.

[0037] In actual operation of drilling pile drivers, the heavy pile hammer continuously and violently impacts the hard rock layer at the bottom of the hole, generating extremely high-intensity impact loads and high-frequency vibrations. If the valve is fixed solely by the radial static friction force of the interference fit, under long-term alternating stress and strong vibration impact, the metal parts are prone to microscopic slippage, leading to valve loosening and a significant risk of falling to the bottom of the pile hole. This invention provides a robust axial barrier for the valve through a limiting retaining ring, effectively resisting the downward inertial impact force generated when the drill bit breaks the rock, effectively eliminating the risk of valve falling off due to vibration, and ensuring the long-term integrity of the one-way valve's anti-backflow sealing line. This avoids serious engineering accidents caused by valve falling off, such as mud backflow, air passage blockage, or even the need for shutdown and hammer removal for major repairs, effectively ensuring the continuity and safety of deep hole construction operations.

[0038] In some embodiments, the openings of the cylindrical mounting holes 11 are evenly distributed circumferentially on the bottom surface of the pile hammer 1; The center line of each cylindrical mounting hole 11 is inclined relative to the horizontal plane. The horizontal projection lines 111 of the center lines of all cylindrical mounting holes 11 are distributed on the side of a regular polygon on the same horizontal plane, and there is a gap between any two adjacent horizontal projection lines 111. The bottom of the pile hammer 1 is also provided with a spiral guide groove corresponding to the opening of each of the cylindrical mounting holes 11. Each spiral guide groove starts from the opening of the corresponding cylindrical mounting hole 11, extends outward in an Archimedean spiral shape and penetrates to the outer wall of the pile hammer 1, so as to form a vortex at the bottom of the pile hammer 1, thereby discharging the drill cuttings along the spiral guide groove.

[0039] The openings of the cylindrical mounting holes 11 are evenly distributed circumferentially on the bottom surface of the pile hammer 1, ensuring the uniform distribution of high-pressure airflow in the hole bottom space. This uniform circumferential distribution allows the airflow ejected from each of the cylindrical mounting holes 11 to cover the bottom surface of the pile hole 100 in a symmetrical pattern, maintaining a balanced hydrodynamic field at the bottom of the pile hammer 1. This balanced flow field distribution not only enables simultaneous, multi-directional blowing of the drill cuttings at the bottom of the pile hole 100, but also prevents the pile hammer 1 from shifting its center of gravity and tilting its posture during suspension, descent, and lifting due to uneven airflow loading, thus improving the stability of the pile hammer 1 during operation.

[0040] This invention defines that the centerline of each cylindrical mounting hole 11 is inclined relative to the horizontal plane, and the horizontal projection lines 111 of the centerlines of all cylindrical mounting holes 11 are distributed on the side of a regular polygon on the same horizontal plane, with a gap between any two adjacent horizontal projection lines 111. This gives the ejected airflow excellent swirling guiding effect. The inclined centerline of each cylindrical mounting hole 11 changes the straight up-and-down ejection trajectory of the high-pressure gas, giving the airflow a lateral thrust. The horizontal projection lines 111 of the centerlines of all cylindrical mounting holes 11 are distributed on the side of a regular polygon on the same horizontal plane, with a gap between any two adjacent horizontal projection lines 111, so that multiple lateral airflows ejected from different cylindrical mounting holes 11 form a tangential force with a unified deflection direction in space. These tangential forces superimpose on each other in the space at the bottom of the pile hole 100, forcibly generating rising fluid vortices rotating in the same direction below the pile hammer 1, allowing the drill cuttings to be lifted and tumble along with the rotating flow field.

[0041] The bottom of the pile hammer 1 is also provided with spiral guide grooves corresponding one-to-one with the openings of the cylindrical mounting holes 11. Each spiral guide groove starts from the opening of the corresponding cylindrical mounting hole 11, extends outward in an Archimedean spiral shape, and penetrates to the outer wall of the pile hammer 1. This provides a smooth guide channel for swirling slag removal. After the high-pressure airflow is ejected from the opening of the cylindrical mounting hole 11, it directly enters the corresponding spiral guide groove. The Archimedean spiral structure of the spiral guide groove conforms to the natural outward motion trajectory of the fluid, reducing the flow resistance when the airflow diffuses outward. During the process of forming a swirling flow at the bottom of the pile hammer 1, these spiral guide grooves serve as slag removal paths, discharging the drill cuttings along the spiral guide grooves. Under the dual guidance of the fluid swirling flow and the spiral guide channel, the drill cuttings move smoothly towards the outer wall of the pile hammer 1 and flow into the surrounding rising mud, thus being carried away from the bottom of the hole, which greatly improves the smoothness and discharge capacity of deep hole cuttings.

[0042] In some embodiments, the lower end of the rotating mandrel is integrally formed with a flange, which is fixedly connected to the pile hammer 1 by bolts.

[0043] The flange provides a large annular base support surface for the bottom end of the rotating mandrel. This large planar structure transforms the originally localized concentrated stress area at the end of the rotating mandrel into a large contact stress area. The large contact surface effectively disperses the localized high pressure generated during the impact operation of the heavy hammer, allowing the longitudinal excitation force from the pile hammer 1 below to be evenly distributed across the entire bottom surface of the flange. Simultaneously, the flange structure radially expands the geometric dimensions of the connection, enhancing the connection node's resistance to lateral shear force and lateral bending moment. This ensures the vertical stability of the rotating mandrel under complex stress conditions at the bottom of the hole, preventing skewing due to uneven stress, and thus maintaining the stability of the entire coaxial rotating pneumatic system's operating trajectory.

[0044] The flange is fixedly connected to the pile hammer 1 by bolts. As fasteners, the bolts provide a strong and quantifiable axial preload clamping force during assembly, ensuring a high-strength, rigid fit between the bottom surface of the flange and the top mounting surface of the pile hammer 1. In the operating environment of giant, heavy-duty equipment facing severe impacts and continuous vibrations, the strong preload force resists the tendency for micro-slippage between components caused by vibrations, preventing loosening or detachment of the connection nodes and ensuring a constant relative spatial position between the rotating mandrel and the pile hammer 1. Furthermore, the bolted connection provides excellent disassembly and ease of maintenance in this area. When it is necessary to clean the fluid channels inside the rotating mandrel, or to inspect and replace relevant components after long-term high-pressure use, the rotating mandrel can be quickly separated from the pile hammer 1 by removing the bolts. This reduces the maintenance difficulty and downtime of large piling equipment, improving the continuity of on-site operations and the reliability of long-term equipment operation.

[0045] In some embodiments, a confluence air chamber 13 is formed inside the pile hammer 1 near the top, and the inner cavity of the rotating mandrel is connected to each air passage through the confluence air chamber 13; The inside of the manifold 13 is provided with a porous buffer baffle 14, which divides the manifold 13 into an upper jet buffer chamber and a lower pressure stabilizing and diverting chamber. The porous buffer plate 14 is provided with multiple throttling buffer holes; Multiple air passages 10 are evenly spaced along the inner circumference of the pile hammer 1, and the upper end of each air passage 10 is connected to the pressure stabilizing and diverting cavity.

[0046] This invention defines a converging air chamber 13 located near the top of the pile hammer 1, with the inner cavity of the rotating mandrel connected to the converging air chamber 13. This provides ample transition buffer space for externally input high-pressure gas within the pile hammer 1. When high-pressure airflow is input via the rotating mandrel, it is often accompanied by a relatively high flow velocity and concentrated local kinetic energy. The converging air chamber 13 allows air entering from a narrow channel to expand in volume and decrease in velocity, preventing fluid shock waves and pressure surges caused by high-speed airflow directly impacting downwards through the narrow channel. This spatial expansion design serves to converge airflow and smooth energy, ensuring a smooth transition of pressure transmission within the gas supply system.

[0047] The gas confluence chamber 13 is horizontally divided by a porous buffer baffle 14, which separates it into an upper jet buffer chamber and a lower pressure-stabilizing and diverting chamber. This layered structure further refines the airflow distribution path within the pile hammer 1. The jet buffer chamber, as the first receiving space after the high-pressure gas enters, receives the initial airflow injected by the rotating mandrel, providing a first-stage weakening and buffering of its longitudinal kinetic energy. Subsequently, the airflow passes through the porous buffer baffle 14 and enters the pressure-stabilizing and diverting chamber. The pressure-stabilizing and diverting chamber acts as a uniform gas storage tank, allowing the gas, after primary buffering, to re-establish a balanced static pressure field within this area. The coordinated operation of these two chambers ensures a smooth transition of internal gas pressure from a dynamic impact state to a static, stable pressure state.

[0048] The porous buffer plate 14 has multiple throttling buffer holes. This feature provides precise guidance and constraint on the microscopic movement trajectory of the airflow. The presence of multiple throttling buffer holes forces the airflow to undergo forced diversion and throttling pressure reduction as it passes through the porous buffer plate 14.

[0049] Multiple air channels 10 are evenly spaced along the inner circumference of the pile hammer 1, and the upper end of each air channel 10 is connected to the pressure-stabilizing and diverting cavity. Under the combined action of the aforementioned airflow buffering and pressure-stabilizing mechanism, a uniformly distributed fluid pressure field is formed within the pressure-stabilizing and diverting cavity. The upper end of each air channel 10 is connected to the pressure-stabilizing and diverting cavity, ensuring that all air channels 10 are under the same initial pressure environment when receiving gas input. Simultaneously, the evenly spaced distribution of multiple air channels 10 along the inner circumference of the pile hammer 1 allows the pressure-equalized gas to be evenly distributed to each downward-extending channel with equal flow rate and velocity. This equal-pressure, equal-flow distribution pattern ensures that the airflow ejected from various positions at the bottom of the pile hammer 1 has a consistent purging intensity, preventing uneven slag discharge due to local pressure imbalances and improving the symmetry and balance of the overall slag and chip removal operation.

[0050] In some embodiments, the bottom of the pile hammer 1 has a plurality of carbide teeth 15 protruding for crushing rock, and these protruding carbide teeth 15 form a chip removal channel 16 at the bottom of the pile hammer 1 (if the bottom of the pile hammer 1 is not provided with a spiral guide groove, then carbide teeth 15 and chip removal channel 16 can be provided). The orifice at the lower end of each of the air passages 10 is located at the bottom of the chip removal channel 16 to prevent the valve 5 from colliding with and being damaged by the rock layer when the pile hammer 1 falls and impacts the rock layer.

[0051] This invention specifies that the bottom of the pile hammer 1 has multiple protruding carbide teeth 15 for rock breaking. These carbide teeth 15 possess excellent hardness and wear resistance, and their protruding placement on the bottom of the pile hammer 1 makes them the primary working surface for direct contact and impact with the rock strata at the bottom of the borehole. During the reciprocating lifting and lowering motion of the pile hammer 1, these protruding carbide teeth 15 concentrate the gravity potential energy of the pile hammer 1 onto a small contact area, generating enormous pressure, thereby successfully breaking the hard bedrock below and ensuring that the pile hammer 1 possesses powerful rock-breaking drilling capabilities.

[0052] These protruding carbide teeth 15 create a chip removal channel 16 at the bottom of the pile hammer 1. Because the carbide teeth 15 are arranged in a protruding pattern, a natural height difference exists between adjacent teeth 15, thus forming the chip removal channel 16. The chip removal channel 16 provides ample space at the bottom of the pile hammer 1, allowing newly generated rock fragments and drill cuttings to quickly enter and temporarily reside within the chip removal channel 16 after the carbide teeth 15 break the rock. This structural design facilitates the outward flow of drill cuttings, preventing excessive accumulation of rock fragments at the end faces of the carbide teeth 15, ensuring that the carbide teeth 15 can directly impact the unbroken rock surface during the next impact, thus improving the performance of continuous rock breaking operations.

[0053] This invention specifies that the orifice at the lower end of each air passage 10 is located at the bottom of the chip removal channel 16. This spatial arrangement cleverly combines the paths for chip blowing and chip removal. Placing the orifice at the lower end of each air passage 10 at the bottom of the chip removal channel 16 allows the high-pressure airflow ejected from the orifice to be directly blown outward along the chip removal channel 16. The high-pressure airflow expands and releases inside the chip removal channel 16, applying a direct thrust to the drill cuttings temporarily stored therein, causing the drill cuttings to tumble rapidly along with the mud and be pushed away from the bottom area of ​​the pile hammer along the direction of the chip removal channel 16. This airflow guiding effect makes the chip removal process smoother and accelerates the cleaning speed of the bottom surface of the hole.

[0054] In some embodiments, at least one slag discharge guide channel is provided on the outer side wall of the pile hammer 1 along the axial or helical direction. The slag discharge guide channel extends upward from the bottom of the pile hammer 1 and penetrates to the top end face of the pile hammer 1 so that the drill cuttings are discharged upward along the slag discharge guide channel.

[0055] This invention specifies that at least one slag discharge guide channel is formed on the outer wall of the pile hammer 1 along the axial or helical direction. This creates a dedicated fluid passage space between the outer wall of the pile hammer 1 and the borehole wall 100. During pile hole 100 drilling, the outer wall of the pile hammer 1 is typically close to the borehole wall, resulting in a narrow annular space and significant resistance to fluid flow. By creating the slag discharge guide channel on the outer wall of the pile hammer 1, the cross-sectional area of ​​this local region is expanded, providing a low-resistance upward channel for the drilling mud carrying drill cuttings.

[0056] This invention further defines the slag discharge guide channel as extending upwards from the bottom of the pile hammer 1 and penetrating to the top end face of the pile hammer 1. This fully continuous structural design establishes a fluid transport link between the high-pressure area at the bottom of the pile hammer and the low-pressure area at the top of the pile hammer. When the air compressor 200 injects high-pressure airflow into the bottom of the hole through the air passage 10 and blows up the drill cuttings at the bottom of the hole, the mud mixed with a large amount of drill cuttings is in a high-pressure expansion state in the flow field at the bottom. The slag discharge guide channel extends upwards from the bottom of the pile hammer 1, directly receiving and guiding this high-pressure mixed fluid rich in drill cuttings. The design of penetrating to the top end face of the pile hammer 1 ensures the continuity and smoothness of the fluid's upward path, so that the mixed fluid is not obstructed by the abrupt change in the shape of the pile hammer 1 during the upward process, reducing the kinetic energy loss and local fluid resistance of the fluid during upward movement.

[0057] Meanwhile, at least one slag discharge guide channel is provided along the axial or spiral direction. If the channel is axially oriented, it provides a shorter linear upward path, allowing the fluid carrying drill cuttings to flow upwards at a faster speed, increasing the slag discharge rate per unit time. If the channel is spirally oriented, it follows the rotational upward trend of the fluid inside the borehole 100 caused by the movement of the pile hammer. The spiral slag discharge guide channel can apply a certain tangential guiding force to the rising fluid, keeping the drill cuttings and mud in a swirling state during the upward movement. This swirling upward movement increases the fluid's travel distance within the borehole, which is beneficial for large drill cuttings to be pushed into the channel and towards the borehole wall edge under centrifugal force, reducing the probability of drill cuttings falling back to the bottom of the borehole and improving the stability of the slag discharge process.

[0058] Ultimately, through the coordinated operation of the aforementioned structures, drill cuttings are discharged upwards along the cuttings discharge guide channel. Under the combined effect of the reciprocating lifting and lowering motion of the pile hammer and the airflow injected towards the bottom of the hole, the cuttings discharge guide channel acts as a flow channel, accelerating the upward migration of the sediment at the bottom of the hole. This structure reduces the concentration of drill cuttings at the bottom of the hole, preventing repeated deposition of drill cuttings at the bottom of the pile hammer 1. It also reduces the fluid resistance during the vertical movement of the pile hammer in the deep hole, improving the smoothness of the lifting and lowering motion of the pile hammer and ensuring the stable progress of deep hole drilling operations.

[0059] In some embodiments, a tension-following take-up and release device is also included, which includes a support frame 6, a take-up and release drum 61, a second rotary joint 62, and a torque limiter. The support frame 6 is set on the ground, the take-up and undo drum 61 is rotatably mounted on the support frame 6, and the hose 4 is wound around the take-up and undo drum 61; The second rotary joint 62 is located at the rotation axis of the winding and unwinding drum 61. The fixed end of the second rotary joint 62 is connected to the air compressor 200 pipeline on the ground. The rotating end of the second rotary joint 62 is connected to the end of the hose 4 away from the first rotary joint 3. Thus, one end of the hose 4 is connected to the air compressor 200 through the second rotary joint 62. The torque limiter is connected to the central shaft 611 of the take-up and undo drum 61.

[0060] To achieve the aforementioned winding torque, those skilled in the art can employ various existing transmission structures. For example, the torque limiter can be a torque motor with a tension controller; it can also be a hydraulic motor with a constant-pressure relief valve connected in parallel in a hydraulic drive circuit; or a slip transmission mechanism connected to a constant-speed power source via a magnetic powder clutch; or it can be a purely mechanical constant-force spiral spring assembly. All of the above structures can maintain a set rotational torque during passive unwinding and active winding.

[0061] This invention also includes a tension-following retraction device, which comprises a support frame 6, a retraction drum 61, a second rotary joint 62, and a torque limiter. The support frame 6 is mounted on the ground, providing a stable foundation for the entire pipeline storage and distribution system, ensuring the stability and structural rigidity of the ground facilities during operation. The retraction drum 61 is rotatably mounted on the support frame 6, and the flexible hose 4 is wound around it. This spatial layout centralizes and orderly arranges the long-distance flexible hoses 4 that were originally scattered across the construction site, preventing the hoses 4 from becoming knotted, folded, or damaged by other construction equipment on the ground, thus improving the cleanliness of the construction site and the safety of pipeline operation. Simultaneously, the rotatable design of the retraction drum 61 allows the flexible hose 4 to be released and retrieved in real time according to the depth changes of the pile hammer within the pile hole 100, meeting the actual working requirements of dynamic adjustment of pipeline length in deep-hole lifting operations.

[0062] The second rotary joint 62 is located at the rotation axis of the take-up and unwinding drum 61. The fixed end of the second rotary joint 62 is connected to the air compressor 200 pipeline on the ground, and the rotating end of the second rotary joint 62 is connected to the end of the hose 4 away from the first rotary joint 3. During the frequent forward and reverse rotation of the take-up and unwinding drum 61 as it rises and falls with the pile hammer, the hose 4 wound on the drum needs to rotate synchronously, while the air compressor 200 pipeline on the ground remains stationary. The second rotary joint 62 here forms a fluid dynamic transmission hub. Its fixed end remains stationary to connect to the air compressor 200 pipeline, while its rotating end rotates together with the take-up and unwinding drum 61 and the hose 4, ensuring smooth conduction of high-pressure gas during the transfer from the stationary air compressor 200 pipeline to the rotating hose 4. This structure cuts off the transmission and accumulation of torsional stress at the source of the pipeline, ensuring that even with the continuous dynamic expansion and contraction of the hose 4, the high-pressure airflow can still be steadily and continuously delivered to the pile hammer at the bottom of the hole, thus guaranteeing the continuity and reliability of the airflow transmission.

[0063] The torque limiter is connected to the central shaft 611 of the take-up and release drum 61. During the reciprocating lifting and lowering motion of the pile hammer, the moving speed and stress state of the hose 4 change drastically. The torque limiter precisely constrains and dynamically adjusts the rotational torque of the take-up and release drum 61. When the pile hammer rapidly falls and pulls the hose 4, the torque limiter provides appropriate yielding resistance to prevent the hose 4 from being excessively stretched and generating tensile stress exceeding the material's bearing capacity, protecting the hose 4 from tearing and breakage. When the pile hammer rises, the torque limiter drives the take-up and release drum 61 to provide the corresponding winding torque in a timely manner, keeping the hose 4 in a moderately taut state and preventing the hose 4 from bending, stacking, or being jammed and damaged by drilling traction equipment inside the pile hole 100 due to redundant length. Through the coordinated operation of the above components, the tension-following take-up and release device achieves automated tension management and continuous fluid supply for the hose 4 in complex construction environments, improving the sensitivity and stability of the overall pipeline system in conjunction with the main body's lifting and lowering movements.

[0064] In some embodiments, the bottom end of the valve 5 is higher than the orifice at the bottom of the air passage 10, and a wear-resistant alloy coating is provided on the inner wall of the air passage 10. The wear-resistant alloy coating is located below the valve 5 and extends to the orifice at the bottom of the air passage 10.

[0065] This invention defines that the bottom end of the valve 5 is higher than the orifice at the bottom of the air passage 10. This spatial positioning feature provides a reliable buffer and concealment space for the valve 5 in the complex environment at the bottom of the pile hole 100. During the reciprocating lifting and lowering and gravity impact of the impact drilling device of the percussion pile driver on the rock strata at the bottom of the hole, the orifice at the bottom of the air passage 10 is in close contact with hard rock, large-particle gravel, and high-concentration mud. By positioning the bottom end of the valve 5 higher than the orifice at the bottom of the air passage 10, the valve 5 is retracted into the air passage 10. When the bottom of the pile hammer impacts the rock strata, even if the gravel at the bottom of the hole is squeezed and splashes upward, or if the high-pressure mud generates an upward backflow instantaneously, this retraction distance can act as a buffer zone, preventing the hard solid material at the bottom of the hole from directly contacting or impacting the delicate valve 5 component. This structural layout prevents the moving parts of the valve 5 from deforming, breaking, or jamming due to collisions with external objects, ensuring the sensitivity and sealing reliability of the valve 5 during opening and automatic closing, and extending the service life of the control components under harsh working conditions.

[0066] This invention specifies that the inner wall of the air passage 10 is provided with a wear-resistant alloy coating. When the air compressor 200 supplies air to the hose 4, the airflow opens the valve 5 and is ejected out of the air passage 10. The airflow has a high velocity in the lower end of the air passage 10. During the up-and-down movement of the pile hammer, the airflow often carries some fine drill cuttings and mud, forming a solid-liquid-gas mixture with strong scouring properties. The wear-resistant alloy coating has high surface hardness and wear resistance. When it is attached to the inner wall of the air passage 10, it can build a robust protective layer on the surface of the base metal material of the air passage 10. When the high-speed flowing mixture generates intense friction and scouring inside the air passage 10, the wear-resistant alloy coating can resist the cutting and erosion of drill cuttings, preventing material loss and thinning of the inner wall of the air passage 10 due to long-term high-speed friction, thus ensuring the structural strength and internal channel size stability of the air passage 10.

[0067] This invention further clarifies that the wear-resistant alloy coating is located below the valve 5 and extends to the orifice at the bottom of the air passage 10. This feature precisely positions the wear-resistant protection area. The area below the valve 5 is precisely the flow channel where the high-pressure gas expands and its flow velocity increases after being ejected, and it is also the area where external mud first rushes in and rubs against the inner wall of the air passage 10 when the gas supply stops. Placing the wear-resistant alloy coating below the valve 5 can specifically strengthen this severely eroded flow channel without interfering with the conventional structure of the air passage 10 above the valve 5. Furthermore, the wear-resistant alloy coating extends to the orifice at the bottom of the air passage 10, ensuring that the edge at the junction of the air passage 10 and the bottom surface of the pile hammer is fully wrapped and protected. This prevents the high-pressure gas flow containing drill cuttings from enlarging and eroding the edge of the orifice when it exits, avoids airflow divergence and velocity reduction caused by orifice deformation and diameter expansion, ensures the concentration of the high-pressure gas jet pattern and the purging kinetic energy, and maintains the long-term slag removal performance of the pile hammer.

[0068] According to another aspect of the present invention, a method for operating the impact drilling device of the self-closing air passage percussion pile driver is also provided, comprising the following steps: 1) The pile hammer 1 is suspended on the steel rope 301 of the drilling pile driver 300. One end of the hose 4 is connected to the fixing sleeve of the first rotary joint 3, and the other end of the hose 4 is connected to the air compressor 200 on the ground through a two-position three-way valve. The two-position three-way valve has one air inlet and two air outlets. The air inlet is connected to the air compressor 200, one of the air outlets is connected to one end of the hose 4, and the other air outlet is connected to the atmospheric environment. 2) The pile hammer 1 falls to impact the bottom of the hole. At the same time as the pile hammer 1 contacts the bottom of the hole, the two-position three-way valve is controlled to connect the air passage, so that the airflow output by the air compressor 200 is sprayed out from the hole opening through the hose 4 and the air passage 10 to blow up the drill cuttings at the bottom of the hole, thereby causing the drill cuttings to rise along the hole wall with the mud and be discharged from the hole opening of the pile hole 100. 3) The punching and piling machine 300 drives the pile hammer 1 to lift. At the same time as lifting, the two-position three-way valve is controlled to switch the state to cut off the air passage to the hose 4 and unload and empty the airflow output by the air compressor 200, thereby pausing the air supply to the hose 4. At this time, the valve 5 automatically closes. 4) Repeat steps 2) and 3) until the depth of the pile hole 100 reaches the design requirements; during this cycle, the air compressor 200 always maintains the operation of supplying air to the two-position three-way valve.

[0069] In step 1), one end of the hose 4 is connected to the fixing sleeve of the first rotary joint 3, and the other end of the hose 4 is connected to the air compressor 200 on the ground via a two-position three-way valve, thus constructing a gas transmission pipeline system from the ground to the underground. The two-position three-way valve, located between the hose 4 and the air compressor 200, provides a control center for the pipeline system to quickly respond to fluid on / off commands. This connection method ensures that the system can accurately control the execution of gas supply and cut-off actions during subsequent high-frequency cyclic piling operations, laying the foundation for the smooth operation of the entire process.

[0070] In step 2), the pile hammer 1 falls to impact the bottom of the hole. Simultaneously with the contact of the pile hammer 1 with the bottom of the hole, the two-position three-way valve is connected to the air passage, allowing the airflow output from the air compressor 200 to be ejected from the hole opening through the hose 4 and the air passage 10 to blow up the drill cuttings at the bottom of the hole. The ejection of the airflow is synchronized with the contact of the pile hammer 1 with the bottom of the hole, allowing the airflow to directly act on the drill cuttings, which are now loosened by the impact, giving them upward kinetic energy. This causes the drill cuttings to rise along the hole wall with the mud and be discharged from the hole opening of the pile hole 100. The intervention of the airflow accelerates the upward movement of the drill cuttings carried by the mud, promotes the circulation of fluid inside the pile hole 100, and allows the drill cuttings to detach from the bottom area in a timely manner, maintaining the relative exposure of the rock strata at the bottom of the hole, which is beneficial for the pile hammer 1 to carry out subsequent continuous direct impact actions.

[0071] In step 3), the drilling and piling machine 300 drives the pile hammer 1 to lift. Simultaneously, the two-position three-way valve is switched to cut off the air path to the hose 4 and unload and vent the airflow output from the air compressor 200. This unloading and venting action directly guides the high-pressure gas, preventing excessive internal pressure caused by gas accumulation inside the pipeline when the fluid is cut off. This maintains the pressure balance between the airflow source and the fluid pipeline, reducing the probability of structural fatigue in the hose 4 due to frequent alternating high pressure and extending its service life. Simultaneously, with the suspension of air supply to the hose 4, the valve 5 automatically closes. The automatic closing of the valve 5 blocks the inward seepage of fluid from the bottom of the hole, preventing high-concentration mud containing drill cuttings from flowing backward into the air passage 10 under hydrostatic pressure. This maintains the cleanliness and unobstructed flow of the air passage 10, eliminating the arduous process of manually lifting the hammer to clear blockages.

[0072] In step 4), the constant operating conditions keep the internal components of the air compressor 200 in a stable working range, reducing current surges and wear caused by frequent starts and stops, and ensuring the continuity and stability of gas output. The cyclical execution of this method combines the internal air supply action, the air path cut-off action, and the unloading and venting action in an orderly manner, ensuring the continuity of the work process and improving the overall work progress rate and the stability of system operation.

[0073] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An impact drilling device for a self-closing air passage percussion pile driver, characterized in that, Includes the suspended gantry, pile hammer, first rotary joint, hoses, and valves, among which: The top of the suspension gantry is provided with a lifting hole for connecting steel ropes. The bottom of the suspension gantry is rotatably connected to the top of the pile hammer through a turntable bearing, so that the pile hammer has a vertical rotation center line when suspended. The outer ring of the turntable bearing is fixedly connected to the suspension gantry by bolts, and the inner ring of the turntable bearing is fixedly connected to the pile hammer by bolts. The pile hammer has multiple air channels inside, and the lower end of each air channel extends to the bottom of the pile hammer. The rotation center line of the first rotary joint is coaxial with the center line of the turntable bearing. The first rotary joint includes a fixed sleeve and a rotating mandrel that are rotatably fitted. The fixed sleeve is fixedly connected to the suspension gantry through a rigid connector. The rotating mandrel is fixedly connected to the pile hammer, and the inner cavity of the rotating mandrel is connected to each of the air passages respectively. One end of the hose is connected to the fixed sleeve, and the other end of the hose is used to connect to the air compressor on the ground; Each of the air passages is provided with a valve at its lower end, so that when the air compressor supplies air into the hose, the airflow opens the valve and sprays out of the air passage, and when the air compressor stops supplying air, the valve automatically closes to prevent drill cuttings from passing through the valve and causing blockage in the air passage.

2. The impact drilling device for a self-closing air passage percussion pile driver according to claim 1, characterized in that, Each of the air passages has a cylindrical mounting hole at its lower end, and a valve is installed in each cylindrical mounting hole. A limiting ring is also provided at the opening of the cylindrical mounting hole to prevent the valve from falling downward.

3. The impact drilling device for a self-closing air passage percussion pile driver according to claim 2, characterized in that, The openings of the cylindrical mounting holes are evenly distributed circumferentially on the bottom surface of the pile hammer. The centerline of each cylindrical mounting hole is inclined relative to the horizontal plane. The horizontal projection lines of the centerlines of all cylindrical mounting holes are distributed on the side of a regular polygon on the same horizontal plane, and there is a gap between any two adjacent horizontal projection lines. The bottom of the pile hammer is also provided with a spiral guide groove corresponding to the opening of each of the cylindrical mounting holes. Each spiral guide groove starts from the opening of the corresponding cylindrical mounting hole, extends outward in an Archimedean spiral shape and penetrates to the outer wall of the pile hammer, so as to form a vortex at the bottom of the pile hammer, thereby discharging the drill cuttings along the spiral guide groove.

4. The impact drilling device for a self-closing air passage percussion pile driver according to claim 1, characterized in that, The lower end of the rotating mandrel is integrally formed with a flange, which is fixedly connected to the pile hammer by bolts.

5. The impact drilling device for a self-closing air passage percussion pile driver according to claim 1, characterized in that, The pile hammer has a confluence air chamber near the top, and the rotating mandrel is connected to each of the air passages through the confluence air chamber; The manifold chamber is laterally provided with a porous buffer baffle, which divides the manifold chamber into an upper jet buffer chamber and a lower pressure stabilizing and diverting chamber. The porous buffer plate is provided with multiple throttling buffer holes; Multiple air passages are evenly spaced along the inner circumference of the pile hammer, and the upper end of each air passage is connected to the pressure stabilizing and diverting cavity.

6. The impact drilling device for a self-closing air passage percussion pile driver according to claim 1, characterized in that, The bottom of the pile hammer has multiple protruding carbide teeth for breaking rock, which make the bottom of the pile hammer form a chip removal channel. The orifice at the lower end of each of the air passages is located at the bottom of the chip removal channel to prevent the valve from colliding with and being damaged by the rock layer when the pile hammer falls and impacts the rock layer.

7. The impact drilling device for a self-closing air passage percussion pile driver according to claim 1, characterized in that, At least one slag discharge guide channel is provided on the outer side wall of the pile hammer along the axial or spiral direction. The slag discharge guide channel extends upward from the bottom of the pile hammer and penetrates to the top end face of the pile hammer so that the drill cuttings can be discharged upward along the slag discharge guide channel.

8. The impact drilling device for a self-closing air passage percussion pile driver according to claim 1, characterized in that, It also includes a tension-following take-up and release device, which comprises a support frame, a take-up and release drum, a second rotary joint, and a torque limiter. The support frame is set on the ground, the take-up and undo drum is rotatably mounted on the support frame, and the hose is wound around the take-up and undo drum; The second rotary joint is located at the rotation axis of the winding and unwinding drum. The fixed end of the second rotary joint is connected to the air compressor pipeline on the ground, and the rotating end of the second rotary joint is connected to the end of the hose away from the first rotary joint. The torque limiter is connected to the central shaft of the take-up and undo drum.

9. The impact drilling device for a self-closing air passage percussion pile driver according to claim 1, characterized in that, The bottom of the valve is higher than the orifice at the bottom of the air passage. A wear-resistant alloy coating is provided on the inner wall of the air passage. The wear-resistant alloy coating is located below the valve and extends to the orifice at the bottom of the air passage.

10. A method for operating the impact drilling apparatus according to any one of claims 1 to 9, characterized in that, Includes the following steps: 1) Suspend the pile hammer on the steel rope of the drilling pile driver, connect one end of the hose to the fixing sleeve of the first rotary joint, and connect the other end of the hose to the air compressor on the ground through a two-position three-way valve; 2) The pile hammer falls to impact the bottom of the hole. At the same time as the pile hammer contacts the bottom of the hole, the two-position three-way valve is controlled to connect the air passage, so that the airflow output by the air compressor is sprayed out from the hole opening through the hose and the air passage to blow up the drill cuttings at the bottom of the hole, thereby causing the drill cuttings to rise along the hole wall with the mud and be discharged from the hole opening. 3) The drilling and piling machine drives the pile hammer to lift. At the same time as lifting, the two-position three-way valve is controlled to switch the state to cut off the air passage to the hose and unload and empty the airflow output by the air compressor, thereby pausing the air supply to the hose. At this time, the valve automatically closes. 4) Repeat steps 2) and 3) until the depth of the pile hole reaches the design requirements; during this cycle, the air compressor always keeps supplying air to the two-position three-way valve.

Images