Embedded device for mine engineering blasting

Abstract

The invention relates to the technical field of mine engineering, and discloses an embedded device for mine engineering blasting, which comprises an end cover, a plurality of expansion valves capable of radially moving are uniformly distributed at the bottom of the end cover in the circumferential direction, and a hollow cylinder with a conical opening in the lower end is defined by the plurality of expansion valves; an expansion plug matched with the conical opening is movably assembled in the conical opening, and the inner side face of the lower end of the expansion valve is provided with an expansion inclined face in sliding fit with the outer circle inclined face of the expansion plug; the upper end of the expansion plug is connected with a positioning disc, a hollow threaded rod is rotationally installed at the upper end of the end cover, and the lower end of the hollow threaded rod sequentially penetrates through the positioning disc and the expansion plug and is in threaded connection with the positioning disc. According to the device, a double anchoring mechanism is formed by combining the huge friction force between the expansion valve and the hole wall and the mechanical interlocking force between the anchoring teeth and the rock mass, the anti-pulling strength is far better than that of a traditional device only depending on friction, strong explosion impact can be effectively resisted, and the device is prevented from flying out.

Description

Technical Field

[0001] This invention relates to the field of mining engineering technology, specifically to a pre-embedded device for blasting in mining engineering. Background Technology

[0002] In blasting operations in mining engineering, the stability and sealing of pre-embedded devices are directly related to the blasting effect and operational safety. Currently, traditional blasting pre-embedded devices face the following two major technical challenges: 1. Poor installation stability: Existing pre-embedded devices usually rely on precise matching with pre-excavated drill pits to achieve fixation. If the pit size is slightly large, gaps will be generated between the device and the rock mass, resulting in unstable installation. During blasting, this instability will cause the device to shift or vibrate, causing leakage of blasting energy and loss of directional control, which seriously affects the effect of directional blasting and makes it impossible to achieve precise rock crushing and throwing control. 2. The connection structure is prone to failure and the pull-out resistance is insufficient: Many devices use threaded connections to fix the sleeve and the end cap. However, under the action of a violent blast shock wave, the threaded connection may loosen, causing high-pressure blasting gas to leak directly out through the sleeve opening. This not only greatly reduces the blasting efficiency and increases the amount of explosives consumed, but more seriously, the loosened device components may fly out of the borehole under the action of the explosion and become high-speed projectiles, posing a great safety threat to personnel and equipment.

[0003] Therefore, there is an urgent need in this field for a blasting pre-embedding device that can adapt to different borehole sizes, achieve reliable mechanical locking, and provide strong pull-out resistance, so as to fundamentally improve the efficiency and safety of blasting operations. Summary of the Invention

[0004] To achieve the above objectives, the present invention adopts an integrated solution that combines expansion anchoring, mechanical locking, and enhanced pull-out resistance. The core objective is to drive the expansion plug upward by a hollow threaded rod, which forces the circumferential expansion flap to expand radially and press against the hole wall. Through the cooperation of the locking wedge block and the wedge groove, self-locking is achieved after expansion. The anchoring teeth with reverse teeth penetrate deep into the rock mass, providing mechanical interlocking pull-out resistance far exceeding friction.

[0005] The present invention proposes a pre-embedded device for blasting in mining engineering, comprising an end cap, wherein multiple radially movable expansion petals are evenly distributed around the bottom of the end cap, and the multiple expansion petals surround to form a hollow cylinder with a conical opening at the lower end; an expansion plug adapted to the conical opening is movably fitted inside the conical opening, and an expansion inclined surface is provided on the inner side of the lower end of each expansion petal, which slides in cooperation with the outer circumferential inclined surface of the expansion plug; a positioning plate is connected to the upper end of the expansion plug, and a hollow threaded rod is rotatably mounted on the upper end of the end cap, the lower end of which passes through the positioning plate and the expansion plug in sequence, and is threadedly connected to the positioning plate; by rotating the hollow threaded rod, the positioning plate and the expansion plug are driven to move upward, forcing the expansion petals to expand radially; The expansion valve adopts a fan-ring structure design. The circumferentially distributed layout ensures uniform force distribution during radial expansion. The conical opening and the inclined surface of the expansion plug form an efficient force transmission structure. Rotating the hollow threaded rod can realize the axial movement of the expansion plug, which is then converted into the radial expansion force of the expansion valve. This structure does not require complex drive components, is easy to operate, and has a controllable expansion stroke. It can adapt to the gap requirements of drilling excavation. In addition, the outward expansion valve will compact the rock and soil on the borehole sidewall, increase frictional resistance, and further improve installation stability.

[0006] As a further optimization of the present invention, the upper end face of the positioning disk is provided with a radially sliding locking wedge and an elastic component that drives the locking wedge to have an outward movement tendency; the lower end center of the end cover is provided with a locking groove adapted to the positioning disk, and the side wall of the locking groove is provided with wedge-shaped grooves corresponding to the locking wedges; when the positioning disk moves upward into the locking groove, the locking wedges are embedded in the corresponding wedge-shaped grooves under the action of the elastic component, thereby achieving mechanical locking; The locking wedge and wedge groove adopt a wedge-shaped surface fit design, which can form a reverse self-locking after being embedded, effectively resisting the reverse force brought by the explosion vibration and avoiding thread reversal or component retraction; the elastic component provides continuous radial thrust to the locking wedge, ensuring that locking can be completed quickly after the positioning plate is in place, without additional operation, which improves the convenience and stability of the device installation.

[0007] As a further optimization of the present invention, the elastic component includes a radially movable cavity disposed inside the positioning disk, a guide rod fixed inside the radially movable cavity, a guide block slidably sleeved on the guide rod, and a spring sleeved on the guide rod; the two ends of the spring respectively abut against the inner wall of the radially movable cavity and the guide block; the upper end of the guide block passes through the movable groove opened at the upper end of the positioning disk and is fixedly connected to the locking wedge block; The cooperation between the guide rod and the guide block ensures that the locking wedge slides smoothly in the radial direction, avoiding jamming; the pre-compression design of the spring provides a stable elastic driving force, and the spring is confined within the radial moving cavity to prevent it from falling off or failing due to vibration during the bursting process, ensuring the long-term reliability of the elastic component.

[0008] As a further optimization of the present invention, the bottom of the expansion flap is fixed with a plurality of anchoring teeth, the free end of the anchoring teeth is provided with a reverse tooth, the anchoring teeth are made of metal springs, and the middle part forms a downward protrusion, so that when the expansion flap expands, the free end of the anchoring teeth can drive the reverse tooth to embed into the rock and soil of the borehole sidewall. The anchoring teeth made of metal spring material have both elasticity and rigidity. When initially entering the borehole, the protrusion is deformed by the expansion flap, causing the free end of the anchoring tooth to extend radially into the soil. When the expansion flap expands, it can also expand further outward, ensuring that the inverted teeth are tightly embedded in the rock and soil. The barbed structure of the inverted teeth forms a mechanical interlock, transforming the traditional friction pull-out resistance into a dual pull-out resistance of friction and mechanical interlock, significantly improving the pull-out strength of the device and effectively preventing the device from flying out during blasting.

[0009] As a further optimization of the present invention, the upper end of the hollow threaded rod is rotatably connected to the end cap via a one-way bearing; a drive ring is installed at the top end of the hollow threaded rod. The one-way bearing restricts the hollow threaded rod to rotate only in the direction of the drive expansion, preventing reverse rotation caused by burst vibration or misoperation, and ensuring stable expansion. The drive ring provides operators with a convenient force application point and can be quickly rotated with tools such as wrenches, reducing installation labor intensity and improving work efficiency.

[0010] As a further optimization of the present invention, the inner ring of the drive ring is hinged with a plurality of circumferentially distributed baffles by a hinge and a torsion spring; in the natural state, the plurality of baffles partially cover the opening of the drive ring, forming a limiting structure for the detonating element. The baffle closes naturally under the action of the torsion spring, which can limit and hold the inserted detonating element, preventing it from shaking or falling off in the borehole. When the detonating element is inserted, the baffle can automatically flip to avoid it and automatically reset after insertion. This does not affect the installation of the detonating element and protects its tail wire, preventing the wire from being compressed or worn.

[0011] As a further optimization of the present invention, an axially extending guide groove is provided on the upper inner side of the expansion valve; a guide plate that slides axially with the guide groove is fixed on the outer periphery of the positioning disk. The sliding fit between the guide groove and the guide plate provides precise guidance for the axial movement of the positioning plate, avoiding uneven force on the expansion plug caused by the positioning plate offset. The side wall of the guide groove is designed to be parallel to the expansion slope, ensuring that the guide plate can still slide smoothly when the expansion flap expands radially without affecting the expansion stroke, while ensuring the tightness of the assembly of each component.

[0012] As a further optimization of the present invention, the lower end face of the end cap is provided with a radially extending T-shaped radial groove; the upper end of the expansion valve is fixed with a T-shaped anti-detachment post that slides in cooperation with the T-shaped radial groove. The radial groove of the T-shaped structure and the anti-detachment column form an anti-detachment limit, which allows the expansion valve to slide freely in the radial direction and prevents the expansion valve from falling off during expansion or burst vibration. The T-shaped structure has a large contact area and low sliding resistance, ensuring smooth expansion of the expansion valve and improving the overall structural robustness of the device.

[0013] As a further optimization of the present invention, the lower end of the expansion plug is provided with an inverted bowl-shaped groove, which together with the multiple expansion petals forms an expansion cavity for accommodating the detonating element. The expansion chamber, enclosed by the bowl-shaped groove and the expansion flap, provides an independent protective space for the detonating element, preventing it from being affected by borehole collapse, crushing rocks, or water immersion. The spherical space design of the expansion chamber allows the detonation shock wave to spread evenly, efficiently detonating the outer main charge and improving the utilization rate and directional effect of the blasting energy.

[0014] As a further optimization of the present invention, multiple pre-embedded devices can be connected in series through their hollow threaded rods to form a blasting network that can be detonated in stages. The hollow structure of the hollow threaded rod provides a channel for the detonating element and can also serve as an interface for series connection. After multiple devices are connected in series with fasteners, they can be used with a time-delay fuse to achieve millisecond-level time-delay detonation. This design is suitable for precision-controlled blasting scenarios such as pre-splitting blasting and smooth blasting. It can release blasting energy in a predetermined sequence, effectively control the direction of rock throwing and vibration intensity, and improve the precision level of blasting operations.

[0015] The pre-embedded device for blasting in mining engineering proposed in this invention has the following beneficial effects: (i) It combines the huge frictional force between the expansion valve and the borehole wall with the mechanical interlocking force between the anchoring teeth and the rock mass, forming a dual anchoring mechanism. Its pull-out strength far exceeds that of traditional devices that rely solely on friction, and it can effectively resist strong explosive impacts and prevent the device from flying out. (ii) The unique locking wedge block and wedge groove design automatically achieves mechanical locking after the device expands to the position. This locking structure can effectively prevent loosening caused by thread reversal or component retraction under the impact of blasting vibration, ensuring the stability of the device throughout the blasting process. (iii) The radial expansion of the expansion valve can adapt to boreholes of different sizes within a certain range, ensuring that the outer wall of the device is in close contact with the borehole rock, reducing the installation gap, thereby minimizing the leakage of blasting energy through this path, and ensuring the efficient utilization and directional effect of blasting energy. (iv) The present invention provides a dedicated and protected channel and accommodating space for the detonating element through the combination design of the hollow threaded rod, the bowl-shaped groove at the lower end of the expansion plug and multiple expansion petals, thereby improving the reliability and safety of detonation. Multiple pre-embedded devices can be easily connected in series and combined with a delay fuse to easily realize a millisecond-level delay detonation network, which is suitable for precise control blasting scenarios such as pre-splitting blasting and smooth blasting. (v) The hollow threaded rod is driven by a one-way bearing, which is simple to operate and can prevent accidental reverse rotation. The T-shaped anti-detachment column and other designs ensure the reliability of the moving parts. The overall structure is robust and suitable for harsh mining environments.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a schematic diagram of the first cross-sectional structure of the present invention; Figure 3 This is a schematic diagram of the second cross-sectional structure of the present invention; Figure 4 For the present invention Figure 3 Schematic diagram of the middle end cap; Figure 5 This is a schematic diagram of the completed installation structure of the present invention inside the borehole; Figure 6 This is a partial cross-sectional view of the upper part of the positioning disk of the present invention; Figure 7 For the present invention Figure 2 Enlarged structural diagram at point A; Figure 8 For the present invention Figure 5 Enlarged structural diagram at point B; Figure 9 This is a top view of the drive ring structure of the present invention; Figure 10 This is a top view of the normal structure of the multiple expansion lobes of the present invention; Figure 11 This is a top view of the positioning disk of the present invention.

[0018] Figure descriptions: 1. End cap; 2. Expansion flap; 3. Expansion plug; 4. Expansion ramp; 5. Positioning plate; 6. Hollow threaded rod; 7. Anchoring tooth; 8. Guide groove; 9. Guide plate; 10. Locking wedge; 11. Wedge groove; 12. Radial slide groove; 13. Anti-detachment column; 14. One-way bearing; 15. Drive ring; 16. Locking groove; 17. Radial movable cavity; 18. Guide rod; 19. Guide block; 20. Spring; 21. Movable groove; 22. Back tooth; 23. Baffle; 24. Detonating element. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar symbols denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0020] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0021] Please see Figures 1-11 The pre-embedded device for blasting in mining engineering proposed in this invention includes an end cap 1 and multiple expansion petals 2. The multiple expansion petals 2 are evenly distributed around the bottom of the end cap 1, and the expansion petals 2 can move radially along the bottom of the end cap 1. Each expansion petal 2 is a fan-ring structure, and the multiple expansion petals 2 surround the bottom of the end cap 1 to form a hollow cylinder. The lower end opening of the hollow cylinder is a conical opening and is movably fitted with an expansion plug 3 adapted to it. The lower inner side of each expansion petal 2 has an expansion inclined surface 4. The upper end of the expansion inclined surface 4 is inclined toward the center of the hollow cylinder and is slidably fitted with the outer circular inclined surface of the expansion plug 3. like Figure 2 and Figure 3As shown, the upper diameter of the expansion plug 3 is smaller than the lower diameter, and a positioning disc 5 is installed on the upper end. The positioning disc 5 is axially slidably assembled with the upper cylindrical cavity of the hollow cylinder. A hollow threaded rod 6 is rotatably installed on the upper end of the end cap 1. The lower end of the hollow threaded rod 6 extends into the hollow cylinder and passes through the positioning disc 5 and the expansion plug 3 in sequence. The positioning disc 5 is threadedly connected to the hollow threaded rod 6. By rotating the upper end of the hollow threaded rod 6, the positioning disc 5 moves upward along the hollow threaded rod 6, thereby driving the expansion plug 3 to move upward synchronously. The expansion plug 3 and the expansion inclined surface 4 are utilized... The inclined design allows multiple expansion flaps 2 to slide outwards synchronously, so that the expansion flaps 2 can press against the borehole sidewall and apply a huge normal pressure N to the borehole sidewall. According to the physical formula static friction force F=μ×N (μ is the coefficient of friction), this normal pressure is directly converted into a huge static friction force between the outer wall of the casing and the rock and soil. The direction of this static friction force is axially upward, which constitutes the first and most important line of defense against the device flying out of the borehole. As long as the upward explosive impact force is less than this total static friction force, the casing will be difficult to move.

[0022] like Figure 3 and Figure 11 As shown, each expansion petal 2 has an axially extending guide groove 8 on its upper inner side. Multiple guide plates 9 are installed on the outer periphery of the positioning disk 5. The guide plates 9 and guide grooves 8 are axially slidably assembled, and the multiple guide plates 9 correspond one-to-one with the multiple guide grooves 8, which can guide the positioning disk 5. The side wall of the guide groove 8 is inclined and parallel to the expansion inclined surface 4. The end of the guide plate 9 away from the positioning disk 5 is inclined and adapted to the guide groove 8, so that the guide plate 9 can still slide normally upward during the expansion of the expansion petal 2. When the expansion petal 2 expands to the maximum range, the guide plate 9 slides to the upper end of the inner cavity of the guide groove 8 and does not disengage, ensuring tight assembly.

[0023] like Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 10 as well as Figure 11As shown, a plurality of circumferentially distributed locking wedges 10 are installed on the upper end face of the positioning disk 5. Each locking wedge 10 corresponds to a plurality of expansion flaps 2. The locking wedges 10 can slide radially and abut against the upper inner wall of the expansion flaps 2 under the compression and energy storage action of the elastic component. A locking groove 16 adapted to the positioning disk 5 is opened at the lower center of the end cover 1. A plurality of circumferentially distributed wedge-shaped grooves 11 are opened on the side wall of the locking groove 16. Each wedge-shaped groove 11 corresponds to a plurality of locking wedges 10. When the positioning disk 5 moves upward to the maximum stroke, the positioning disk 5 is located in the locking position. Inside the stop groove 16, at this time, the locking wedge 10 and the wedge groove 11 are at the same horizontal height. Since there is no obstruction at the outer end of the locking wedge 10, the elastic component returns to its extended state and pushes the locking wedge 10 to move radially outward, so that the locking wedge 10 and the wedge groove 11 are inserted. By using the insertion of multiple locking wedges 10 and multiple wedge grooves 11, the positioning disk 5 and the end cover 1 are tightly connected, thereby realizing the positioning of the positioning disk 5 and the end cover 1, and then realizing the locking after the multiple expansion petals 2 are expanded outward, thereby realizing the tight connection between the device and the drill hole and preventing loosening. Furthermore, such as Figure 6 As shown, the upper end of the positioning disk 5 has a plurality of radially movable cavities 17 that are evenly distributed in the circumference and extend radially. The elastic component is disposed inside the radially movable cavity 17. The locking wedge block 10 is slidably disposed on the upper end surface of the positioning disk 5 and is fixedly connected to the movable end of the elastic component. Furthermore, the elastic component includes a guide rod 18 fixedly installed in the radially movable cavity 17, and the axis of the guide rod 18 is parallel to the radially movable cavity 17. A guide block 19 and a spring 20 are slidably installed on the guide rod 18. The guide block 19 is radially slidably assembled with the inner wall of the radially movable cavity 17. The two ends of the spring 20 respectively abut against the guide block 19 and the inner wall of the radially movable cavity 17 near the center of the positioning disk 5. The upper end face of the positioning disk 5 is provided with a movable groove 21 that communicates with the radially movable cavity 17. The upper end of the guide block 19 passes through the movable groove 21 and is fixedly connected to the lower end face of the locking wedge block 10. The movable groove 21 is located on the side away from the center of the positioning disk 5, and the upper end of the guide block 19 is radially slidably assembled with the movable groove 21. like Figure 2In the initial stage shown, the locking wedge 10 abuts against the upper inner wall of the expansion petal 2, the guide block 19 is located at the end of the movable groove 21 away from the expansion petal 2, and the spring 20 is compressed and deformed. When the hollow threaded rod 6 rotates and drives the positioning disk 5 to move upward, the expansion petal 2 expands outward under the upward movement of the expansion plug 3, and a radial gap is generated between the positioning disk 5 and the expansion petal 2. Due to the lack of obstruction on the outer side of the locking wedge 10, the spring 20 gradually extends outward, causing the guide block 19 to drive the locking wedge 10 to gradually move outward in the movable groove 21. When the positioning disk 5... When the upper end moves to near the lower opening of the locking groove 16, and the wedge-shaped inclined surface of the locking wedge 10 contacts the edge of the opening of the locking groove 16, as the positioning plate 5 continues to move upward, the direction of the force is changed by the inclined surface, so that the locking wedge 10 is compressed again until the upper end of the positioning plate 5 enters the locking groove 16, and the locking wedge 10 abuts against the side wall of the locking groove 16. When the positioning plate 5 moves to the highest point, the locking wedge 10 is flush with the wedge groove 11, and the locking wedge 10 moves radially outward and inserts into the wedge groove 11, thereby achieving mechanical locking.

[0024] like Figures 3-5 As shown, the lower end face of the end cap 1 is provided with a plurality of radially distributed and radially extended radial grooves 12. The plurality of radial grooves 12 correspond one-to-one with the upper ends of the plurality of expansion petals 2. Each expansion petal 2 is provided with an anti-detachment post 13 that is slidably assembled with the radial groove 12. Both the radial groove 12 and the anti-detachment post 13 adopt an anti-detachment design with a T-shaped longitudinal section, so that the expansion petal 2 can expand radially outward while being tightly assembled with the end cap 1 without falling off.

[0025] like Figures 3-5 As shown, the upper end of the hollow threaded rod 6 has a smooth shaft section, which is rotatably connected to the end cover 1 via a one-way bearing 14. The end of the smooth shaft section extends to the top of the end cover 1 and is fitted with a drive ring 15. When the drive ring 15 is rotated clockwise or counterclockwise, the drive ring 15 can drive the hollow threaded rod 6 to rotate, thereby driving the positioning disk 5 to move the expansion plug 3 upward. However, when the drive ring 15 rotates in the other direction, it will generate huge resistance and be difficult to rotate, thus making it difficult to drive the hollow threaded rod 6 to rotate in the other direction. As a result, in actual operation, the positioning disk 5 can only move the expansion plug 3 upward and cannot move it downward, which improves the outward expansion stability of the expansion flap 2 and thus improves the installation stability of the device in the borehole.

[0026] Furthermore, such as Figure 9As shown, the inner ring of the drive ring 15 is provided with multiple baffles 23 evenly distributed around the circumference. The baffles 23 are fan-shaped and their outer arc surfaces are hinged to the inner wall of the drive ring 15 through hinges and torsion springs. The baffles 23 can be kept horizontal under the action of the torsion springs, thereby partially covering the opening of the drive ring 15. When it is necessary to place an initiating element such as a detonator, the lower end of the initiating element 24 is inserted into the drive ring 15, so that multiple baffles 23 flip into the drive ring 15 at the same time, and the initiating element 24 can be inserted. Then the initiating element 24 slides down along the hollow inner cavity of the hollow threaded rod 6 to the bottom of the device and is located in the expansion cavity formed by the lower ends of multiple expansion petals 2, which provides sufficient expansion space for the initial explosion of the initiating element 24, so that it can be quickly converted into a spherical shock wave, thereby efficiently detonating the outer main charge. The lead wire at the tail end of the initiating element 24 extends outward through the circular hole formed by multiple baffles 23, so as to remotely control the detonation. Furthermore, multiple of these pre-embedded devices can be connected in series to form a blasting network. By precisely designing the time-delay electronic fuse of the detonating element 24 in each device, a precise detonation sequence at the millisecond level can be achieved. This is crucial for achieving precise blasting such as pre-splitting blasting and smooth blasting. The blasting energy can be released in a predetermined sequence, effectively controlling the direction of blasting, the direction of rock throwing, and the intensity of vibration. Furthermore, the lower end of the expansion plug 3 has an inverted bowl-shaped groove, which cooperates with multiple expansion flaps 2 to provide an all-round protective cover for the detonation element 24, protecting it from the effects of borehole collapse, crushing of gravel, or water immersion, greatly improving the reliability and safety of detonation. In traditional bottom-hole detonation, energy is released from a single point. In this device, since the detonating element 24 is located on the axis of the hollow threaded rod 6, its explosion wave can act more evenly and simultaneously on the entire bottom section of the outer cylindrical charge through the bottom expansion chamber. This helps to generate a more planar and uniform initial stress wave that propagates forward. For scenarios that require a flat blasting surface, such as tunnel contour control, a smoother wall surface with less over- and under-excavation can be obtained.

[0027] Specifically, such as Figure 2 , Figure 3 , Figure 5 , Figure 7 , Figure 8As shown, the bottom of the expansion petal 2 is equipped with anchoring teeth 7. There are multiple anchoring teeth 7, which are evenly distributed along the arc of the expansion petal 2. When the expansion petal 2 is installed in the borehole, under the upward movement of the positioning plate 5 and the expansion plug 3, the expansion petal 2 drives the anchoring teeth 7 to expand outward synchronously, so that the anchoring teeth 7 are inserted into the bottom of the borehole sidewall. These anchoring teeth 7 are like countless tiny barbs, forming a mechanical interlock with the rock and soil. When the expansion petal 2 tends to move upward under the action of explosion, the anchoring teeth 7 will squeeze and try to lift the rock and soil in front of it. The shear and compression strength of the rock and soil is much greater than the friction force, thus providing a pull-out force far exceeding that of pure friction. The anchoring teeth 7 then direct the pull-out force from simple borehole wall friction to the deeper and wider rock and soil area below the borehole wall, mobilizing greater foundation resistance to resist pull-out. Furthermore, such as Figure 7 and Figure 8 As shown, the anchoring tooth 7 is fixedly connected to the bottom of the expansion petal 2. The free end of the anchoring tooth 7 is inclined downward, then bent upward and horizontally, thus forming a downward protrusion in the middle of the anchoring tooth 7. The free end of the anchoring tooth 7 is equipped with a reverse tooth 22. The anchoring tooth 7 is made of metal spring material. When the expansion petal 2 is installed in the borehole, the protrusion of the anchoring tooth 7 contacts the bottom surface of the borehole and is compressed, so that the free end of the anchoring tooth 7 can extend outward and insert into the rock and soil body of the borehole sidewall. When the expansion petal 2 drives the anchoring tooth 7 to expand outward, the reverse tooth 22 also expands outward synchronously. The pull-out resistance is improved by multiple reverse teeth 22, and the anchoring reinforcement is achieved.

[0028] The working principle of this invention is a continuous process of "expansion-locking-anchoring", as detailed below: Step 1, Initial Installation: Place the device into the drilled blast hole; Step 2, Expansion Drive: The operator rotates the drive ring 15 to drive the hollow threaded rod 6 to rotate. Since the hollow threaded rod 6 is threadedly connected to the positioning disk 5, and the positioning disk 5 cannot rotate because it is slidably engaged with the guide groove 8 on the expansion petal 2 through the guide plate 9, the rotational motion of the hollow threaded rod 6 is converted into the upward linear motion of the positioning disk 5 and the expansion plug 3 connected to it. Step 3, Radial Expansion: During the upward movement of the expansion plug 3, its outer conical surface slides relative to the expansion slope 4 at the lower end of the expansion petal 2, generating a radial component force that forces multiple expansion petals 2 to expand outward radially in sync, pressing tightly against the borehole wall. At this time, the inverted teeth 22 at the end of the anchoring teeth 7 at the bottom of the expansion petal 2 also expand outward and penetrate into the surrounding rock mass. Step 4, Mechanical Locking: As the positioning disc 5 moves upward with the expansion plug 3, the expansion flap 2 expands outward under the upward movement of the expansion plug 3, creating a radial gap between the positioning disc 5 and the expansion flap 2. Due to the lack of obstruction on the outer side of the locking wedge 10, the spring 20 gradually extends outward, causing the guide block 19 to drive the locking wedge 10 to gradually move outward through the severely movable groove 21. When the upper end of the positioning disc 5 moves to near the lower end opening of the locking groove 16, and the wedge-shaped inclined surface of the locking wedge 10 contacts the opening edge of the locking groove 16, as the positioning disc 5 continues to move upward, the locking wedge 10 is compressed again until the upper end of the positioning disc 5 enters the locking groove 16, and the locking wedge 10 abuts against the side wall of the locking groove 16. When the positioning disc 5 moves to the highest point, the locking wedge 10 is flush with the wedge groove 11, and the locking wedge 10 moves radially outward and inserts into the wedge groove 11, thus realizing the mechanical locking action and completing the mechanical self-locking. Step 5, Detonation preparation: Insert the detonating element 24 into the opening of the drive ring 15, push the baffle 23 open, and let it fall through the inner hole of the hollow threaded rod 6 into the expansion chamber formed by the bowl-shaped groove at the bottom of the expansion plug 3 and the expansion petal 2. The baffle 23 is reset under the action of the torsion spring, which plays a certain clamping role on the lead wire of the detonating element. Step Six: Resisting Blasting: During blasting, the enormous impact force causes the device to tend to move upward. At this time, the first layer of protection is the static friction force generated between the expansion valve 2 and the borehole wall due to the huge positive pressure. The second layer of protection is the mechanical interlocking between the anchoring teeth 7 and the inverted teeth 22 and the rock mass. Its shear strength is extremely high, and together they form an indestructible pull-out defense line to ensure the stability of the device and the directional release of energy.

[0029] In summary, the pre-embedded device for blasting in mining engineering provided by this invention combines the frictional force of "surface contact" with the mechanical interlocking force of "point penetration," exhibiting extremely excellent pull-out resistance. It achieves automatic mechanical locking in the expanded state, fundamentally solving the problem of vibration loosening. The hollow threaded rod has three functions: transmission, channel, and protection, providing a dedicated and safe housing space for the detonating element, improving detonation reliability. Moreover, multiple devices can be easily connected in series, and a millisecond-level delay detonation network can be easily achieved through preset delay, making it suitable for precise control scenarios such as smooth blasting and pre-splitting blasting. This device upgrades the blasting pre-embedded device from a simple container into a reliable and efficient anchoring system. It can not only significantly improve the blasting effect and energy utilization rate, but also greatly ensure operational safety and prevent the device from flying out. It is an important technological innovation that promotes the development of mine blasting operations towards automation, precision and high safety.

[0030] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A pre-embedded device for blasting in mining engineering, comprising an end cap (1), characterized in that: The bottom of the end cap (1) is evenly distributed with multiple radially movable expansion petals (2), and the multiple expansion petals (2) surround to form a hollow cylinder with a conical opening at the lower end. An expansion plug (3) is movably fitted inside the conical opening, and an expansion slope (4) is provided on the inner side of the lower end of the expansion flap (2) to slide with the outer circumferential slope of the expansion plug (3). The upper end of the expansion plug (3) is connected to the positioning plate (5), and the upper end of the end cap (1) is rotatably mounted with a hollow threaded rod (6). The lower end of the hollow threaded rod (6) passes through the positioning plate (5) and the expansion plug (3) in sequence, and is threadedly connected to the positioning plate (5). By rotating the hollow threaded rod (6), the positioning disk (5) and the expansion plug (3) are driven to move upward, forcing the expansion valve (2) to expand radially.

2. The pre-embedded device for blasting in mining engineering according to claim 1, characterized in that, The upper end face of the positioning disk (5) is provided with a radially sliding locking wedge (10) and an elastic component that drives the locking wedge (10) to have an outward movement tendency; The lower center of the end cap (1) is provided with a locking groove (16) that is compatible with the positioning plate (5), and the side wall of the locking groove (16) is provided with a wedge-shaped groove (11) that corresponds one-to-one with the locking wedge (10). When the positioning disk (5) moves upward into the locking groove (16), the locking wedge (10) is embedded in the corresponding wedge groove (11) under the action of the elastic component, thereby achieving mechanical locking.

3. The pre-embedded device for blasting in mining engineering according to claim 2, characterized in that, The elastic component includes a radial movable cavity (17) disposed inside the positioning disk (5), a guide rod (18) fixed inside the radial movable cavity (17), a guide block (19) slidably sleeved on the guide rod (18), and a spring (20) sleeved on the guide rod (18). The two ends of the spring (20) abut against the inner wall of the radial movable cavity (17) and the guide block (19), respectively; The upper end of the guide block (19) passes through the movable groove (21) opened at the upper end of the positioning plate (5) and is fixedly connected to the locking wedge block (10).

4. The pre-embedded device for blasting in mining engineering according to claim 1, characterized in that, The bottom of the expansion valve (2) is fixed with a plurality of anchoring teeth (7), and the free end of the anchoring teeth (7) is provided with a reverse tooth (22). The anchoring tooth (7) is made of a metal spring with a downward protrusion in its middle, so that when the expansion valve (2) expands, the free end of the anchoring tooth (7) can drive the inverted tooth (22) to embed into the rock and soil of the borehole sidewall.

5. A pre-embedded device for blasting in mining engineering according to claim 1, characterized in that, The upper end of the hollow threaded rod (6) is rotatably connected to the end cap (1) via a one-way bearing (14); A drive ring (15) is installed at the top of the hollow threaded rod (6).

6. The pre-embedded device for blasting in mining engineering according to claim 5, characterized in that, The inner ring of the drive ring (15) is hinged with multiple circumferentially distributed baffles (23) by hinges and torsion springs. In its natural state, the plurality of baffles (23) partially cover the opening of the drive ring (15), forming a limiting structure for the detonating element (24).

7. A pre-embedded device for blasting in mining engineering according to claim 1, characterized in that, The upper inner side of the expansion valve (2) is provided with an axially extending guide groove (8). The outer periphery of the positioning disk (5) is fixed with a guide plate (9) that slides axially with the guide groove (8).

8. The pre-embedded device for blasting in mining engineering according to claim 1, characterized in that, The lower end face of the end cap (1) is provided with a radially extending T-shaped radial groove (12). The upper end of the expansion valve (2) is fixed with a T-shaped anti-detachment column (13) that slides in conjunction with the T-shaped radial groove (12).

9. A pre-embedded device for blasting in mining engineering according to claim 1, characterized in that, The lower end of the expansion plug (3) is provided with an inverted bowl-shaped groove, which together with the multiple expansion petals (2) forms an expansion cavity for accommodating the detonating element (24).

10. A pre-embedded device for blasting in mining engineering according to any one of claims 1-9, characterized in that, Multiple pre-embedded devices can be connected in series through their hollow threaded rods (6) to form a blasting network that can be detonated in segments.

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