Low-clearance rotary drill and method

Abstract

The application belongs to the technical field of bored pile drilling construction, in particular to a low-clearance rotary drilling rig and method. The structure design of the power drill bit at the end is adopted, the power drill bit is lowered into the hole for drilling operation by the power element two telescopic, and the top of the power drill bit is enhanced in torsional stiffness by the telescopic drill rod during the drilling operation, so as to ensure that the perpendicularity deviation is controlled within the allowable range. In addition, the soil suction and discharge assembly is arranged at the power drill bit to perform active dry method negative pressure soil discharge operation, which is high in operation efficiency and good in hole excavation effect, solves the problems of drill bit breakage and drill rod clamping, and the power drill bit cooperates with the multi-stage telescopic structure to adapt to and solve the problem of low-clearance drilling.

Description

Technical Field

[0001] This invention belongs to the field of bored pile construction technology, specifically a low-headroom rotary drilling rig and method. Background Technology

[0002] Rotary drilling rigs are a relatively advanced pile foundation construction technology that has developed in my country in recent years. Known as a "green construction technology," it is characterized by its automatic positioning, vertical drilling, and high-quality hole formation. Rotary drilling rigs are suitable for hole-forming operations in building foundation engineering. They are primarily suitable for construction in soil layers such as sand, cohesive soil, and silty soil, and are widely used in various foundation construction projects, including cast-in-place piles and continuous wall foundation reinforcement.

[0003] Currently, the construction of cast-in-place piles in low-clearance areas is a major weakness in geotechnical engineering machinery construction both domestically and internationally, such as tunnels, indoor factories, and under viaducts. In these confined spaces, traditional construction equipment, such as CN118933554A, CN119553948A, and CN119062240A, uses a top-mounted power unit to drive a multi-stage drill rod and drill bit assembly to complete the rotary drilling cast-in-place pile structure. However, as the drill bit descends deeper, the distance between the power unit and the drill bit gradually increases, easily causing the drill rod to tilt to one side, leading to deviations in borehole verticality. Simultaneously, a large amount of soil accumulates at the drill bit end, significantly increasing the workload on the drill bit and potentially causing drill bit breakage or drill rod jamming.

[0004] In this context, in order to enable rotary drilling rigs to carry out efficient and safe construction, a low-headroom rotary drilling rig with a working height of less than 4 meters, a working depth of 6 meters, and the ability to efficiently remove soil in real time is needed. Summary of the Invention

[0005] The technical problem to be solved by this invention is: how to solve the problems of drill bit breakage, drill rod jamming, and inability to remove soil in a timely and efficient manner in low-headroom drilling equipment.

[0006] To solve the above-mentioned technical problems, the inventors, through practice and summarization, derived the technical solution of this invention, which adopts the following technical solution:

[0007] A low-headroom rotary drilling rig, comprising:

[0008] The drill bit assembly includes a rotary drill bit and a power element 1, which drives the rotary drill bit to rotate and drill downwards.

[0009] The drill bit lifting assembly includes an end plate, the bottom of which is connected to a power element one, and the top of which is equipped with a power element two and a telescopic drill rod.

[0010] The drill bit lifting assembly includes a stand, on which a vertically adjustable lifting platform is mounted. The lifting platform is connected to the top of the telescopic drill rod and the top of the second power element.

[0011] The soil suction and discharge assembly includes a soil discharge pump, a soil discharge pipe, and a soil discharge head. The soil discharge pump is connected to the soil discharge pipe and the soil discharge head, which is installed on an end plate.

[0012] In one embodiment, the telescopic drill rod is a four-section telescopic rod with an extended dimension of 6 meters or more and a retracted dimension of 1.3 meters or less. From top to bottom, they are the first-stage drill rod, the second-stage drill rod, the third-stage drill rod, and the fourth-stage drill rod, and the drill rod size gradually decreases from top to bottom. Each section of the drill rod except the fourth-stage drill rod is provided with a groove inside, and each section of the drill rod except the first-stage drill rod is provided with a locking block at the top inside. The locking block and the groove are elastically locked and adapted to each other.

[0013] Each section of the drill rod is equipped with a soil discharge pipe installation structure on its outer side.

[0014] In one embodiment, the second power element is a multi-stage hydraulic cylinder with a flange mounted on one end and a lifting device mounted on the other end. A clamping ring is mounted on the lifting device, and the clamping ring is connected to the fourth-stage drill pipe.

[0015] In one embodiment, the upright frame is equipped with a winch, four corner frames, and connecting lugs. The winch is installed on the rear side of the upright frame, the four corner frames are fixedly installed on the top of the upright frame and have pulley blocks installed on them, and the connecting lugs are installed on the top of the lifting platform. The connecting lugs are connected to the winch by passing a connecting rope around the pulley blocks on the four corner frames.

[0016] In one embodiment, the drilling rig further includes two sets of single-stage hydraulic cylinders, which are hinged to the mobile vehicle and have their free ends hinged to the rear side of the upright frame. The working height of the drilling rig does not exceed four meters.

[0017] In one embodiment, the outer side of the fourth-stage drill pipe is fitted with an in-hole verticality control component. The in-hole verticality control component includes a fixed sleeve, on which an inflation / deflation device and an expansion airbag are installed. The inflation / deflation device controls the expansion airbag to actively expand and contract. Multiple reinforcing bodies are evenly distributed around the outer circumference of the expansion airbag. Each reinforcing body is slidably fitted onto the fixed sleeve. A battery is embedded in the fixed sleeve to provide power to the inflation / deflation device.

[0018] In one embodiment, elastic trigger 1 and elastic trigger 2 are installed on the inner side of the fixed sleeve, and an axial groove is installed on the outer side of the fourth-stage drill rod. The depth of the axial groove gradually decreases from top to bottom. An exhaust switch of the air filling and exhaust device is provided at the top of the axial groove, and an air filling switch of the air filling and exhaust device is provided at the bottom. Elastic trigger 1 and elastic trigger 2 are slidably engaged in the axial groove.

[0019] Both the first and second elastic triggers include a mounting groove. A trigger terminal and an elastic body are slidably fitted in the mounting groove. The trigger terminal is exposed on the outside of the mounting groove and slidably fitted in the axial slide groove. A U-shaped circuit is provided in the axial slide groove.

[0020] In one embodiment, a fixed seat is installed on the end plate, and two sets of horizontally arranged rotating shafts are installed in the fixed seat. The output end of the power element one is connected to the rotating shaft through a bevel gear set. The transmission shaft is connected to the rotary drilling bit through the bevel gear set. Soil-breaking blades are installed on the rotating shafts and are positioned directly below the soil discharge head.

[0021] In one embodiment, the rotary drilling bit is provided with blades arranged in a spiral pattern.

[0022] In one embodiment, the rotary drilling bit has a hollow internal structure and an open bottom structure. The blades include an upper reaming blade and a lower drilling blade. The upper reaming blade is circumferentially distributed on the outer side of the rotary drilling bit, and the lower drilling blade covers the bottom and outer side of the rotary drilling bit.

[0023] The outer side of the rotary drilling bit is connected to a fixed ring via an electromagnetic socket. The fixed ring is fitted with two movable ring plates and a double-headed electric cylinder. The two movable ring plates are respectively connected to the corresponding output ends of the double-headed electric cylinder. The two movable ring plates are connected to the hole wall pressure plate via a connecting rod.

[0024] The fixed ring is connected to a clearing blade via a connecting rod, and the clearing blade is located inside the rotary drilling bit.

[0025] The top of the rotary drilling bit is equipped with a soil discharge side opening and a rotating cover. A soil discharge ring is located outside the soil discharge side opening, and the soil discharge ring is connected to the soil discharge head.

[0026] Construction methods for low-headroom rotary drilling rigs include:

[0027] Step 1: The mobile vehicle moves the upright to the predetermined drilling position, and two single-stage hydraulic cylinders control the upright to keep it in a vertical state;

[0028] Step 2: Power component one drives the rotary drill bit to rotate, while power component two drives the end plate and drill bit assembly to move down, and the rotary drilling operation begins.

[0029] During rotary drilling, after the clamping ring drives the four-stage drill rod down to the set depth, both power element one and power element two stop working. The elastic trigger one moves to the top of the axial slide 7 and triggers the exhaust switch. The expansion airbag actively exhausts air. After exhausting air, the fixing sleeve moves down until it reaches the bottom of the axial slide 7 and triggers the inflation switch. After the expansion airbag inflates until its outer wall abuts against the hole wall, power element one and power element two restart to continue drilling. The cycle continues until the hole is completed.

[0030] During rotary drilling, the soil removal pumps dryly remove loose soil from the borehole through the soil removal pipes and heads.

[0031] The loose soil inside the hole is further broken up by the rotating shaft and the rotation of the power element, which drives the soil-breaking blades to rotate, preventing the soil discharge head from being blocked.

[0032] or,

[0033] During rotary drilling, loose soil in the hole is discharged through the bottom opening of the rotary drill bit by a soil discharge pump via a soil discharge pipe, soil discharge head, and soil discharge ring, using a dry method under negative pressure. During operation, a pressure sensor is pre-installed inside the soil discharge ring. The change in the pressure sensor value determines whether there is a blockage. When a blockage occurs, the double-headed electric cylinder drives the two moving ring plates to move closer together, and the connecting rod presses the hole wall pressure plate against the hole wall. At this time, the electromagnetic connector separates the fixed ring and the rotary drill bit. The winch drives the rotary drill bit to move up and down repeatedly via the connecting rope or power element two. The cleaning blade cleans the blockage inside the rotary drill bit. After cleaning, the rotary drill bit is reset to the position where the fixed ring and the rotary drill bit are aligned again. The electromagnetic connector reassembles the fixed ring and the rotary drill bit. After the double-headed electric cylinder drives the two moving ring plates away from each other to the initial position, power element one and power element two start working again, driving the rotary drill bit to continue drilling.

[0034] Step 3: After rotary drilling reaches the target depth, ensure that the expansion airbag is in the contracted state, disconnect the circuit of the battery and the charging and degassing device, and the winch and / or power element 2 drive the drill bit assembly upward. The telescopic drill rod retracts until the rotary drill bit disengages from the hole.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. This invention adopts a structure design with a power drill bit at the end. It utilizes the telescopic power element to realize the drilling operation of the power drill bit. During the drilling operation, the top of the power drill bit is reinforced with torsional stiffness through the telescopic drill rod to ensure that the verticality deviation is controlled within the allowable range. Secondly, a soil suction and discharge assembly is set at the power drill bit to carry out active dry negative pressure soil discharge operation. The operation efficiency is high and the excavation and hole formation effect is good. It solves the problems of drill bit breakage and drill rod jamming. The power drill bit combined with the multi-stage telescopic structure can adapt to and solve the problem of low headroom drilling.

[0037] 2. This invention utilizes a telescopic drill rod to lay the excavation pipe, facilitating its efficient and orderly installation. Secondly, the second power element applies axial pressure only to the drill bit, ensuring effective hole formation. The telescopic drill rod and the second power element are connected by a clamping ring for synchronized operation, ensuring torsional rigidity in the top area of ​​the drill bit. A winch is used to lift the drill bit via a connecting rope onto the lifting platform, facilitating the assembly and disassembly of the drill bit, the second power element, and the telescopic drill rod.

[0038] 3. This invention features a hole verticality control component on the outer side of the fourth-stage drill rod. An inflation / deflation device is used to expand and contract the air bladder, ensuring concentricity between the fourth-stage drill rod and the hole wall. This guarantees the verticality of the power drill bit during drilling, especially in unpredictable environments where the drilling location contains hard soil or underground reinforced concrete structures. To ensure verticality during drilling, the air bladder on the fixed sleeve expands and maintains pressure, forming a verticality-maintaining structure at the top of the power drill bit. Furthermore, the inflation / deflation device's trigger mechanism enables inflation / deflation at the end. After deflation, gravity and changes in the axial groove depth allow for automatic descent to a new position within the hole, ensuring concentricity during drilling again. Simultaneously, the air bladder seals the top of the soil suction / discharge area, facilitating soil removal operations.

[0039] 4. The present invention also provides a rotating shaft at the power drill bit, which forms a transmission connection with the rotary drill bit through the rotating shaft and the power output end, thereby further crushing the soil below the discharge head and preventing blockage problems.

[0040] 5. This invention also optimizes the structure of the rotary drilling bit, using a hollow structure with an external soil discharge head to achieve dry soil discharge operations. However, due to the drilling pressure during drilling, blockages can easily occur inside the drill bit. An electromagnetic connector is used to separate the fixed ring and the drill bit. A double-headed electric cylinder drives the moving ring plate to approach, thereby pressing the hole wall pressure plate against the hole wall to provide temporary support for the fixed ring. The up-and-down movement of the cleaning blade is achieved by lifting the drill bit to clear the blockages inside the drill bit. Attached Figure Description

[0041] Figure 1 , Figure 2 This is a schematic diagram of the overall structure of one embodiment of the present invention;

[0042] Figure 3 A structural diagram showing the relationship between the upright frame and the lifting work platform;

[0043] Figure 4 A structural diagram showing the relationship between the drill bit lifting assembly and the drill bit assembly;

[0044] Figure 5 This is a schematic diagram of the structure of the second power element;

[0045] Figure 6 A schematic diagram of a telescopic drill pipe;

[0046] Figure 7 A schematic diagram of a telescopic drill pipe according to another embodiment;

[0047] Figure 8 for Figure 7Cross-sectional view of the connection relationship between the middle fixed sleeve and the fourth-stage drill pipe;

[0048] Figure 9 for Figure 8 A magnified view of a section at point A in the middle;

[0049] Figure 10 for Figure 9 Schematic diagram of the structure of the elastic trigger element;

[0050] Figure 11 for Figure 7 Cross-sectional view of the connection relationship between the fixed sleeve and the fourth-stage drill pipe at another angle;

[0051] Figure 12 for Figure 11 A magnified view of a section at point B in the middle;

[0052] Figure 13 A schematic diagram of a drill bit assembly equipped with soil-breaking blades;

[0053] Figure 14 This is a schematic diagram of the overall structure of another embodiment of the present invention;

[0054] Figure 15 for Figure 14 A schematic diagram of the overall structure of the drill bit assembly;

[0055] Figure 16 for Figure 14 A schematic diagram of one possible scheme for a drill bit assembly;

[0056] Figure 17 for Figure 16 This is a magnified view of a portion of point C;

[0057] Figure 18 This is a structural diagram showing the relationship between the fixing sleeve and the unclogging blade.

[0058] In the diagram: 100, Drill bit assembly; 110, Rotary drill bit; 111, Lower drill blade; 112, Upper reamer; 113, Fixing ring; 114, Electromagnetic socket; 115, Moving ring plate; 116, Double-headed electric cylinder; 117, Unblocking blade; 118, Soil discharge ring cover; 119, Hole wall pressure plate; 120, Power component one;

[0059] 200. Drill bit lifting assembly; 210. End plate; 211. Fixing seat; 212. Rotating shaft; 213. Soil-breaking blade; 220. Power element two; 221. Flange; 222. Lifter; 223. Clamping ring; 230. Telescopic drill rod; 231. Primary drill rod; 232. Secondary drill rod; 233. Tertiary drill rod; 234. Quaternary drill rod; 235. Locking block; 236. Slot; 237. Axial slide groove; 240. Fixing sleeve; 241. Inflation and de-inflation device; 242. Inflatable airbag; 243. Reinforcing body; 244. Elastic trigger element one; 245. Elastic trigger element two;

[0060] 300. Drill bit lifting assembly; 310. Frame; 311. Winch; 312. Four-corner frame; 313. Pulley block; 314. Connecting lug; 315. Connecting rope; 320. Power component two;

[0061] 400. Soil suction and discharge assembly; 410. Soil discharge pump; 420. Soil discharge pipe; 430. Soil discharge head; 500. Single-stage hydraulic cylinder; 600. Mobile vehicle. Detailed Implementation

[0062] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0063] Example 1, as Figure 1 To the diagram Figure 6 As shown, a low-headroom rotary drilling rig includes:

[0064] The drill bit assembly 100 includes a rotary drill bit 110 and a power element 120, which drives the rotary drill bit 110 to rotate and drill downwards.

[0065] The drill bit lifting assembly 200 includes an end plate 210, the bottom of which is connected to a power element 120, and the top of which is equipped with a power element 220 and a telescopic drill rod 230.

[0066] The drill bit lifting assembly 300 includes a stand 310, on which a vertically adjustable lifting worktable 320 is installed. The lifting worktable 320 is connected to the top of the telescopic drill rod 230 and the top of the power element 220.

[0067] The soil suction and discharge assembly 400 includes a soil discharge pump 410, a soil discharge pipe 420, and a soil discharge head 430. The soil discharge pump 410 is connected to the soil discharge head 430 via the soil discharge pipe 420, and the soil discharge head 430 is mounted on the end plate 210.

[0068] During implementation, power element 120 drives the rotary drill bit 110 to rotate, while power element 220 applies downward pressure to the drill bit assembly 100 to achieve drilling and hole formation. At the same time, the telescopic drill rod 230 enhances the torsional rigidity of the drill rod to ensure that the drill bit assembly 100 can drill vertically. Simultaneously, the soil discharge head 430 discharges the loose soil excavated by the rotary drill bit 110 to the outside of the hole through the soil discharge pump 410 and the soil discharge pipe 420.

[0069] In the above implementation scheme, the telescopic drill rod 230 is a four-section telescopic rod with an extended dimension greater than or equal to six meters and a retracted dimension less than or equal to 1.3 meters. This enables low-headroom operation with a working height of less than 4 meters and a working depth of six meters. From top to bottom, the sections are: primary drill rod 231, secondary drill rod 232, tertiary drill rod 233, and quaternary drill rod 234, with the drill rod dimensions gradually decreasing from top to bottom. Each drill rod section, except for the quaternary drill rod 234, has a slot 236 inside. Each drill rod section, except for the primary drill rod 231, has a locking block 235 at its top. The locking block 235 and the slot 236 are elastically locked together. The elastic locking between the locking block 235 and the slot 236 ensures the structural stability at the telescopic joint. Each drill rod section has a soil discharge pipe 420 installation structure on its outer side, with the soil discharge pipes 420 neatly arranged.

[0070] In the above implementation scheme, the second power element 220 is a multi-stage hydraulic cylinder, with a flange 221 installed at one end and a lifting device 222 installed at the other end. A clamping ring 223 is installed on the lifting device 222, and the clamping ring 223 is connected to the fourth-stage drill rod 234. The flange 221 is fixed on the lifting work platform 320, which is provided with mounting holes. The oil pipe of the multi-stage hydraulic cylinder is connected to the hydraulic station on the mobile vehicle from this side, and the soil discharge pipe is led out from this side and connected to the soil discharge pump. It is connected to the fourth-stage drill rod 234 through the clamping ring 223, so that when the rotary drill bit 110 moves down, the telescopic drill rod 230 also moves synchronously, ensuring that the verticality is maintained within the allowable range of torsional stiffness during drilling.

[0071] In the above implementation scheme, to achieve the lifting action of the lifting work platform 320, a winch 311, a four-corner frame 312, and a connecting lug 314 are installed on the upright frame 310. The winch 311 is installed on the rear side of the upright frame 310, the four-corner frame 312 is fixedly installed on the top of the upright frame 310 and a pulley block 313 is installed on it, and the connecting lug 314 is installed on the top of the lifting work platform 320. The connecting lug 314 is connected to the winch 311 by a connecting rope 315 passing around the pulley block 313 on the four-corner frame 312. The winch 311 drives the connecting rope 315 to achieve the lifting action of the lifting work platform 320.

[0072] In the above embodiment, the drilling rig also includes two sets of single-stage hydraulic cylinders 500, which are hinged to the mobile carriage 600, with their free ends hinged to the rear side of the upright frame 310. The working height of the drilling rig does not exceed four meters. The single-stage hydraulic cylinders 500 are externally connected to the hydraulic station on the mobile carriage via oil pipes. By controlling the extension of the two single-stage hydraulic cylinders 500, the verticality of the upright frame 310 can be ensured, thereby ensuring the initial verticality of the drill bit.

[0073] Example 2, as Figure 7 To the diagram Figure 12 As shown in the above implementation scheme, the soil at the drilling location often contains hard soil or underground reinforced concrete structures, which are unpredictable. In order to ensure the verticality of the power drill bit during drilling, the following improvements are made:

[0074] The outer side of the fourth-stage drill rod 234 is fitted with an in-hole verticality control component. The in-hole verticality control component includes a fixed sleeve 240, on which a filling and venting device 241 and an expansion airbag 242 are installed. The filling and venting device 241 controls the expansion airbag 242 to actively expand and contract. Multiple reinforcements 243 are evenly distributed around the outer circumference of the expansion airbag 242. Each reinforcement 243 is slidably fitted onto the fixed sleeve 240. A battery is embedded in the fixed sleeve 240 and provides power to the filling and venting device 241 via a circuit (equipped with a remote control switch). An axial sliding groove 237 is installed on the outer side of the fourth-stage drill rod 234. The filling and venting device can be a combination of a micro air pump and a micro air pump. The pump and control principle are existing mature technologies, so they will not be explained in detail.

[0075] A torque sensor can be added to the power output end of the power element 120. The change of the torque sensor can be used to determine whether there is hard soil. The inflation and deflation of the air bladder 242 is achieved by the inflation and deflation device 241. When inflated, it can abut against the hole wall, thereby ensuring the concentricity of the fourth-stage drill rod 234 and the borehole. Even when encountering hard soil, the verticality of the borehole can be ensured to prevent the drill bit from deviating to one side.

[0076] In the above embodiment, the inner side of the fixed sleeve 240 is equipped with an elastic trigger 1 244 and an elastic trigger 245. The depth of the axial slide groove 237 gradually decreases from top to bottom. The top of the axial slide groove 237 is provided with an exhaust switch of the inflation / deflation device 241, and the bottom is provided with an inflation switch of the inflation / deflation device 241. The elastic trigger 1 244 and the elastic trigger 245 slide in the axial slide groove 237.

[0077] like Figure 10As shown, both the first elastic trigger 244 and the second elastic trigger 245 include a mounting groove. A trigger body terminal and an elastic body are slidably fitted in the mounting groove. The trigger body terminal is exposed on the outside of the mounting groove and slidably fitted in the axial slide groove 237. A U-shaped circuit is provided in the axial slide groove 237. The trigger body terminal has two ends that contact the two ends of the U-shaped circuit respectively. The two ends are connected to the two ends of the battery respectively through a line. Since the trigger body terminal is sliding, a conductive plate can be provided on the inner wall of the mounting groove and connected to the two ends of the battery. The terminal is always in contact with the conductive plate to ensure that the circuit is always in the connected state.

[0078] The difference from the above scheme is that the expansion airbag operates intermittently. After each drilling to a certain depth, it is deflated, contracts, and falls to the bottom of the fourth-stage drill rod 234 to be re-inflated. The inflation and deflation of the expansion airbag is achieved by elastic trigger 1 244 and elastic trigger 2 245 at different positions, thereby maintaining the allowable verticality error range during the drilling process.

[0079] Example 3, in the above implementation scheme, as follows Figure 13 As shown, a fixed seat 211 is installed on the end plate 210, and two sets of horizontally arranged rotating shafts 212 are installed in the fixed seat 211. The output end of the power element 120 forms a transmission connection with the rotating shaft 212 through a bevel gear set. The transmission shaft forms a transmission connection with the rotary drilling bit 110 through the bevel gear set. A soil-breaking blade 213 is installed on the rotating shaft 212, and the soil-breaking blade 213 is located directly below the soil discharge head 430.

[0080] The rotary drilling bit 110 is equipped with blades arranged in a spiral pattern.

[0081] During the drilling process, the transmission cooperation formed by the power element 120 (motor), the rotary drill bit 110 and the rotating shaft 212 ensures that the soil at the discharge head 430 is broken soil, thus preventing the problem of blockage.

[0082] Example 4, as Figures 14 to 18 As shown, the difference lies in the structure of the rotary drilling bit and the connection relationship of the soil discharge head. Of course, the structure of embodiment 2 can also be applied to this embodiment. In the above implementation scheme, the structure of the drill bit is optimized, and the rotary drilling bit and the soil discharge head 430 are directly connected, which can discharge the soil in the hole in a timely and efficient manner, so that the soil accumulation at the end of the drill bit is minimized, reducing the rotary cutting resistance of the drill bit and facilitating drilling.

[0083] The rotary drilling bit 110 has a hollow internal structure and an open bottom. The blades include an upper reaming blade 112 and a lower drilling blade 111. The upper reaming blade 112 is distributed circumferentially on the outer side of the rotary drilling bit 110, and the lower drilling blade 111 covers the bottom and outer side of the rotary drilling bit 110. The lower drilling blade 111 and the upper reaming blade 112 are used to drill the hole twice in succession to reduce the drilling resistance.

[0084] The outer side of the rotary drilling bit 110 is connected to a fixed ring 113 via an electromagnetic socket 114. Two movable ring plates 115 and a double-headed electric cylinder 116 are mounted and slidably fitted on the fixed ring 113. The two movable ring plates 115 are respectively connected to the corresponding output ends of the double-headed electric cylinder 116. The two movable ring plates 115 are connected to a hole wall pressure plate 119 via a connecting rod. The electromagnetic socket 114 includes an installation port on the fixed ring 113. An electromagnet, an elastic body, and a connector are installed in the installation port. The connector is exposed on the outside of the installation port.

[0085] The fixed ring 113 is connected to the unblocking blade 117 via the connecting rod, and the unblocking blade 117 is located inside the rotary drilling bit 110;

[0086] The top of the rotary drilling bit 110 is provided with a soil discharge side opening and a rotating cover 118 on the outside of the soil discharge side opening. The soil discharge ring 118 is connected to the soil discharge head 430.

[0087] A pressure sensor is added inside the soil discharge ring shroud 118. The change in pressure sensor is used to determine whether there is a blockage. When a blockage occurs, the double-headed electric cylinder 116 drives the two moving ring plates 115 to move closer to each other, which in turn drives the hole wall pressure plate 119 to move outward and press tightly against the hole wall. At this time, the fixed ring 113 is fixed. After the electromagnet is energized, it can attract the connector to separate the fixed ring 113 and the rotary drilling bit 110. With the lifting worktable 320 lifting the drill bit up and down multiple times, the fixed ring 113 moves up and down relative to the drill bit, and the clearing blade 117 will clear the blockage inside the rotary drilling bit 110.

[0088] Construction methods for low-headroom rotary drilling rigs include:

[0089] Step 1: The moving vehicle 600 moves the upright 310 to the predetermined drilling position, and the two single-stage hydraulic cylinders 500 control the upright 310 to keep it in a vertical position.

[0090] Step 2: Power component 120 drives the rotary drill bit 110 to rotate, while power component 220 drives the end plate 210 and drill bit assembly 100 to move downward, and the rotary drilling operation begins.

[0091] During rotary drilling, after the clamping ring 223 drives the fourth-stage drill rod 234 down to the set depth, both power element 120 and power element 220 stop working. The elastic trigger 244 moves to the top of the axial slide 237 and triggers the exhaust switch. The expansion airbag 242 actively exhausts air. After exhausting, the fixing sleeve 240 descends until it reaches the bottom of the axial slide 237 and triggers the inflation switch. After the expansion airbag 242 inflates until its outer wall abuts against the hole wall, power element 120 and power element 220 restart to continue drilling. The cycle continues until the hole is completed.

[0092] One method is as follows: During rotary drilling, the soil discharge pump 410 discharges the loose soil in the hole through the soil discharge pipe 420 and the soil discharge head 430. The loose soil in the hole is further crushed by the rotation shaft 212 along with the rotation of the power element 210, which drives the soil crushing blade 213 to rotate, thus preventing the soil discharge head 230 from being blocked.

[0093] Another method is as follows: During rotary drilling, loose soil in the hole is discharged dry through the bottom opening of the rotary drill bit 110 by the soil discharge pump 410 via the soil discharge pipe 420, soil discharge head 230, and soil discharge ring 118 under negative pressure. During operation, a pressure sensor is pre-installed inside the soil discharge ring 118. The change in the pressure sensor value determines whether there is a blockage. When a blockage occurs, the double-headed electric cylinder 116 drives the two moving ring plates 115 to move closer to each other, and the connecting rod abuts the hole wall pressure plate 119 against the hole wall. At this time, the electromagnetic connector 114 separates the fixed ring 113 from the rotary drill bit 110. The winch 311 drives the rotary drilling bit 110 to move up and down repeatedly via the connecting rope 315 or the second power element 220. The cleaning blade 117 cleans the blockage inside the rotary drilling bit 110. After cleaning, the rotary drilling bit 110 returns to the original position where the fixed ring 113 and the rotary drilling bit 110 are aligned again. The electromagnetic connector 114 reassembles the fixed ring 113 and the rotary drilling bit 110. After the double-headed electric cylinder 116 drives the two moving ring plates 115 away from each other to the initial position, the first power element 110 and the second power element 220 start working again, driving the rotary drilling bit 110 to continue drilling.

[0094] Step 3: After the rotary drilling reaches the target depth, ensure that the expansion airbag 242 is in the contracted state, disconnect the circuit of the battery and the charging and decharging device 241, and the winch 311 and / or power element 220 drive the drill bit assembly 110 upward, and the telescopic drill rod 230 retracts until the rotary drilling bit 110 disengages from the hole.

[0095] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. The substitutions may be replacements of some structures, devices, or method steps, or they may be complete technical solutions. Equivalent substitutions or modifications made to the technical solutions and inventive concepts of the present invention should all be covered within the scope of protection of the present invention.

Claims

1. A low-clearance rotary excavator characterized by, The utility model relates to a rotary drilling rig, which comprises a drill bit assembly (100), a drill bit lifting assembly (200), a drill bit lifting assembly (300) and a soil suction and discharge assembly (400). The drill bit assembly (100) comprises a rotary drill bit (110) and a power element I (120), and the power element I (120) drives the rotary drill bit (110) to rotate and drill downward. The drill bit lifting assembly (200) comprises an end plate (210), the bottom of the end plate (210) is connected with the power element I (120), and the top of the end plate (210) is provided with a power element II (220) and a telescopic drill rod (230). The drill bit lifting assembly (300) comprises a vertical stand (310), and a lifting workbench (320) is installed on the vertical stand (310) and can be adjusted in vertical position, the lifting workbench (320) is connected with the top of the telescopic drill rod (230) and the top of the power element II (220). The soil suction and discharge assembly (400) comprises a soil discharge pump (410), a soil discharge pipe (420) and a soil discharge head (430), the soil discharge pump (410) is connected with the soil discharge pipe (420) and the soil discharge head (430), and the soil discharge head (430) is installed on the end plate (210). The telescopic drill rod (230) is a four-section telescopic rod with a stretching size greater than or equal to six meters and a shrinking size less than or equal to 1.3 meters, and comprises a first drill rod (231), a second drill rod (232), a third drill rod (233) and a fourth drill rod (234) from top to bottom, and the size of the drill rod gradually decreases from top to bottom. Each drill rod is provided with a soil discharge pipe (420) mounting structure on the outside. The power element II (220) is a multi-stage hydraulic cylinder, one end of which is provided with a flange plate (221) and the other end of which is provided with a pulling device (222), the pulling device (222) is provided with a clamping ring (223), and the clamping ring (223) is connected with the fourth drill rod (234). The fourth drill rod (234) is provided with a hole verticality control assembly on the outside, the hole verticality control assembly comprises a fixed sleeve (240), the fixed sleeve (240) is provided with a gas charging and discharging device (241) and an inflatable air bag (242), the gas charging and discharging device (241) controls the inflatable air bag (242) to actively expand and shrink, a plurality of reinforcing bodies (243) are distributed on the outside of the inflatable air bag (242) at equal intervals in the circumferential direction, each reinforcing body (243) is in sliding fit with the fixed sleeve (240), a storage battery is embedded in the fixed sleeve (240) to provide electric energy for the gas charging and discharging device (241), and the fourth drill rod (234) is provided with an axial sliding groove (237) on the outside. The inner side of the fixed sleeve (240) is provided with elastic trigger one (244) and elastic trigger two (245), the depth of the axial sliding groove (237) gradually decreases from top to bottom, the top of the axial sliding groove (237) is provided with the exhaust switch of the charging and exhausting device (241), the bottom is provided with the inflation switch of the charging and exhausting device (241), the elastic trigger one (244) and the elastic trigger two (245) are slidingly fitted in the axial sliding groove (237); The elastic trigger one (244) and the elastic trigger two (245) both include a mounting slot, a trigger body terminal and an elastic body are slidingly fitted in the mounting slot, the trigger body terminal is partially exposed to the outside of the mounting slot and is slidingly fitted in the axial sliding groove (237), and the axial sliding groove (237) is provided with a U-shaped circuit.

2. A low headroom rotary excavator according to claim 1, characterized in that The stand (310) is provided with a winch (311), a four-corner frame (312) and a connecting lug (314), the winch (311) is installed on the rear side of the stand (310), the four-corner frame (312) is fixedly installed on the top of the stand (310) and is provided with a pulley block (313) thereon, the connecting lug (314) is installed on the top of the lifting workbench (320), the connecting lug (314) passes through the pulley block (313) on the four-corner frame (312) through a connecting rope (315) and is connected with the winch (311).

3. A low headroom rotary excavator according to claim 2, wherein, The drilling machine further comprises two groups of single-stage hydraulic cylinders (500), which are hingedly connected to the moving vehicle (600) and are hingedly connected to the rear side of the stand (310), and the working height of the drilling machine is not more than four meters.

4. The low headroom rotary excavator of claim 3, wherein, The end plate (210) is provided with a fixed seat (211), two groups of transversely arranged rotating shafts (212) are installed in the fixed seat (211), the output end of the power element one (120) is in transmission cooperation with the rotating shaft (212) through a bevel gear set, the transmission shaft is in transmission cooperation with the rotary drilling head (110) through a bevel gear set, the rotating shaft (212) is provided with a soil breaking blade (213), and the soil breaking blade (213) is arranged directly below the soil discharging head (430).

5. A low headroom rotary excavator according to claim 4, wherein, The rotary drilling head (110) is internally hollow and is provided with an open structure at the bottom, the blade includes an upper hole expanding piece (112) and a lower hole drilling piece (111), the upper hole expanding piece (112) is circumferentially distributed on the outer side of the rotary drilling head (110), and the lower hole drilling piece (111) covers the bottom and the outer side of the rotary drilling head (110); The outer side of the rotary drilling head (110) is connected with a fixed ring (113) through an electromagnetic socket body (114), the fixed ring (113) is provided with two moving ring plates (115) and a double-head electric cylinder (116) slidingly fitted thereon, the two moving ring plates (115) are connected with the corresponding output ends of the double-head electric cylinder (116), respectively, and the two moving ring plates (115) are commonly connected with a hole wall pressing plate (119) through connecting rods; The fixed ring (113) is connected with a blockage cleaning blade (117) through a connecting rod, and the blockage cleaning blade (117) is located in the interior of the rotary drilling head (110); The top of the rotary drilling head (110) is provided with a soil discharge side opening and a rotating cover, and a soil discharge ring cover (118) is arranged outside the soil discharge side opening.

6. A method of construction of a low headroom rotary excavator as claimed in claim 5, characterised in that, The method comprises the following steps: Step 1: the moving vehicle (600) moves the stand (310) to a predetermined drilling position, and two single-stage hydraulic cylinders (500) control the stand (310) to keep vertical; Step 2: the power element one (120) drives the rotary drilling head (110) to rotate, and the power element two (220) drives the end plate (210) and the drill head assembly (100) to move downward, and the rotary drilling operation is performed; During the rotary drilling, after the clamping ring (223) drives the four-stage drill rod (234) to move downward to a set depth, the power element one (120) and the power element two (220) are both temporarily stopped, the elastic trigger one (244) moves to the top of the axial sliding groove (237) and triggers the exhaust switch, the inflatable air bag (242) actively exhausts, the fixed sleeve (240) moves downward, and moves downward until the bottom of the axial sliding groove (237) and triggers the inflation switch, after the inflatable air bag (242) is inflated to the outer wall and abuts against the hole wall, the power element one (120) and the power element two (220) are restarted to perform the drilling work, and the cycle operation is performed until the hole forming operation is completed; During the rotary drilling, the loosened soil in the hole is discharged outside the hole by the soil discharge pump (410) through the soil discharge pipe (420) and the soil discharge head (430) in a dry manner; The loosened soil in the hole is rotated by the rotating shaft (212) along with the power element one (120) to drive the soil cutting blade (213) to rotate to further cut the loosened soil, so as to prevent the soil discharge head (430) from being blocked; Alternatively, During the rotary drilling, the loosened soil in the hole is discharged outside the hole by the soil discharge pump (410) through the soil discharge pipe (420), the soil discharge head (430) and the soil discharge ring cover (118) in a dry manner, and a pressure sensor is prearranged in the soil discharge ring cover (118) during the operation, the value change of the pressure sensor is detected to determine whether there is a blockage problem, when the blockage occurs, the double-head electric cylinder (116) drives the two moving ring plates (115) to approach each other, and the hole wall pressing plate (119) is pressed against the hole wall through the connecting rod, at this time, the electromagnetic socket body (114) separates the fixed ring (113) and the rotary drilling head (110), the winch (311) drives the rotary drilling head (110) to reciprocate up and down through the connecting rope (315) or the power element two (220) for multiple times, the unblocking blade (117) cleans the blockage in the rotary drilling head (110), after the cleaning is completed, the rotary drilling head (110) is reset to the position where the fixed ring (113) and the rotary drilling head (110) correspond again, the electromagnetic socket body (114) reassembles the fixed ring (113) and the rotary drilling head (110), the double-head electric cylinder (116) drives the two moving ring plates (115) to move away from each other to the initial position, and then the power element one (120) and the power element two (220) are restarted to drive the rotary drilling head (110) to continue the drilling operation. Step 3, when the rotary excavating reaches the target depth, make sure the inflatable air bag (242) is in the contracted state, disconnect the circuit between the battery and the air charging and discharging device (241), the winch (311) and or the power element two (220) drive the drill bit assembly (100) to go up, the telescopic drill rod (230) retracts until the rotary drill bit (110) is separated from the hole.

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