A large angle swelled shell anchor head for loose rock anchoring

Abstract

A large-angle expanding shell anchor head for anchoring loose rock strata relates to the field of anchoring equipment technology. By improving the anchor head structure, the opening direction of the expanding plates is changed, significantly increasing the opening angle while also enhancing the anchoring strength through mechanical self-locking. The anchor head includes a main body and multiple tensioning components arranged circumferentially thereon. The main body has an axial inner cavity, one end of which has a threaded interface for connecting the anchor rod, and the other end is a closed end. The tensioning components include expanding plates, each comprising an inner connecting section near the axis of the main body and an outer anchoring section for contacting the rock strata. The inner connecting section is pivotally connected to the closed end. The expanding plates can rotate outward from an initial contracted state under the action of the axial thrust of the anchor rod, and when a set maximum unfolding angle is reached, the inner connecting sections of each expanding plate adhere to each other to form a self-locking structure. The outer surface of the outer anchoring section has several friction-enhancing structures.

Description

Technical Field

[0001] This utility model relates to the field of anchoring equipment technology, specifically to a large-angle expansion shell type anchor head for anchoring loose rock strata. Background Technology

[0002] Anchor heads have a wide range of applications throughout industry, including building grouting, bridge construction, slope stabilization, structural installation, and the Internet. Hollow grouting anchors, in particular, can effectively improve the stability and safety of underground engineering projects. The main structure of an anchor head consists of an anchor head column and a expansion plate. In practical applications, the hollow anchor rod pushes the expansion plate out to abut against the inner wall of the pre-drilled hole, and then the anchor rod is pulled back to pre-tighten, thus completing the fastening.

[0003] However, in loose rock strata, due to the unstable geological conditions of the rock strata, the gripping force and friction force provided by the rock mass are significantly reduced, and the stress distribution is uneven. Therefore, when opening anchor holes, it is necessary to drill anchor holes larger than those of anchor rods, and the expansion angle requirements of the expansion plates are also greater. Furthermore, traditional straight-tube grouting anchor rods and anchor heads are prone to pull-out damage due to their small expansion angle and reliance on friction anchoring.

[0004] Application CN202210145109.9 discloses an expansion shell anchor head with a large expansion size and an anchor rod including the anchor head, comprising an internally hollow expansion shell wedge and two expansion shell plates that can slide along the expansion shell wedge. The worktable has symmetrical inclined surfaces on both sides, which are inclined from the worktable toward the connecting part. Each of the two inclined surfaces has a sliding groove, and the two sliding grooves are centrally symmetrically arranged through the axis of the work part. The expansion shell plates are provided with sliders that slide in cooperation with the sliding grooves. In this application, the maximum expansion size of the expansion shell on the anchor head can reach three times the diameter of the anchor head, which avoids the shortcomings of small expansion size of the expansion shell, poor anchoring effect or even failure to form support. Moreover, due to the excellent expansion size of the expansion shell, the anchor head has a large margin after expansion, so the size of the anchor head can be reduced, which facilitates the entry of the anchor rod and anchor head into the anchor hole, and the anchoring bearing capacity is strong.

[0005] Although the application increases the expansion size, its anchor head is shortened, and the inclination of its expansion shell needs to be greater. The expansion shell is also appropriately shortened. When this structure is used in loose rock strata, the changes in various angles may exert a pushing force on the expansion shell, causing the expansion shell to slide along the sliding groove. Due to the large inclination, even a small amount of sliding may cause the expansion shell to open significantly, affecting the support strength and anchorage bearing capacity. Utility Model Content

[0006] I. Technical problems to be solved This invention addresses the shortcomings of existing technologies by proposing a large-angle expanding shell anchor head for anchoring loose rock strata. By improving the anchor head structure, the opening direction of the expanding plates is changed, which significantly increases the opening angle while also enhancing the anchoring strength through mechanical self-locking.

[0007] II. Specific Technical Solutions A large-angle expanding shell anchor head for anchoring loose rock strata includes an anchor head body and multiple tensioning components disposed circumferentially thereon. The anchor head body has an axial inner cavity, one end of which has a threaded interface for connecting an anchor rod, and the other end is a closed end. The tensioning components include expanding plates, each expanding plate having an inner connecting section near the axis of the anchor head body and an outer anchoring section for contacting the rock strata. The inner connecting section is pivotally connected to the closed end. The expanding plates can rotate outward from an initial retracted state under the action of the axial thrust of the anchor rod, and when a set maximum unfolding angle is reached, the inner connecting sections of each expanding plate fit together to form a self-locking structure. The outer surface of the outer anchoring section is provided with several friction-enhancing structures.

[0008] The basic principle of this scheme is: Before the anchor head is inserted into the anchor hole, each expansion joint is in a closed state. At this time, the inner connecting sections fit together, and the overall profile is slender, making it easy to insert into the pre-drilled anchor hole with a larger diameter in the loose rock layer. The rotation of the hollow anchor rod converts the continuous spiraling motion into a thrust on the expansion joint. Since the expansion joint is connected to the closed end through a pivotal connection, this thrust forces the expansion joint to rotate outward around the axis of rotation, rather than sliding axially. As the expansion joint continues to rotate, its opening angle continuously increases, which is very suitable for the large opening angle required by loose rock layers. When the rotation reaches the set maximum angle, the sides of the inner connecting sections of each expansion joint fit together tightly and work together with the closed end to form a stable self-adhesive structure. The locking structure effectively resists the closing tendency caused by the reaction force of the rock strata, solving the problem of potential retraction of traditional sliding structures in loose rock strata. In practical applications, the fully opened and self-locking expansion plate will break through and penetrate the rock strata. The friction protrusions on its outer connection part are firmly pressed against the rock strata on the anchor hole wall. At this time, the anchor rod is pulled back, and the entire device enters a high-strength anchoring state. Due to its mechanical self-locking and the constraint and limitation formed with the rock strata after penetration, its pull-out resistance and strength far exceed those of traditional anchor heads that rely solely on friction. When applied to relatively soft rock strata, the volume of its anchor head end is larger, and after grouting reinforcement, a larger anchor head is formed with better strength.

[0009] Preferably, the circumferential outer wall of the anchor head body is provided with multiple first oblique surfaces, and each first oblique surface has an installation groove. The expansion piece is assembled onto the anchor head body through the installation groove, and the edge of the inner connecting section of the expansion piece fits against the first oblique surface. The width of the installation groove on the closed end side is greater than the width on the threaded interface side. The outer surface of the outer anchoring section is provided with several friction-enhancing structures. The beneficial effect of this preferred embodiment is that the inclined first oblique surface provides a natural guide and initial angle for the rotation of the expansion piece, making its unfolding process smoother. The width difference caused by the oblique surface facilitates better accommodation of the expansion piece and better fit with the expansion piece structure. Through the layout of the installation groove, structural interference with the anchor head body is avoided, and large-angle expansion is easily achieved.

[0010] Preferably, in the initial retracted state, the inner connecting sections of each expansion joint are fitted together, and an inclined guide surface is provided on the side near the threaded interface. The inclined guide surfaces of multiple expansion joints constitute a guide space for accommodating and guiding the end of the anchor rod. The beneficial effects of this preferred embodiment are: the initial and rotational fitting ensures the integrity of the anchor head before installation, facilitating insertion into the borehole; the inclined guide surface can more smoothly guide the end of the anchor rod to insert into and contact the expansion joint, efficiently transferring the axial thrust to the expansion joint, reducing the resistance during insertion and the impact on the components, and improving installation efficiency.

[0011] Preferably, the end of the inner connecting section is arc-shaped, and during the rotation of the expansion piece, the arc-shaped structures of multiple inner connecting sections abut each other. The advantage of this preferred embodiment is that the arc-shaped structure facilitates better rotation of the expansion piece.

[0012] Preferably, a limiting boss is provided on the inner side of the closed end, and a second beveled surface that mates with the limiting boss is provided on the inner connecting section of the expanding piece; when the expanding piece is extended to its maximum angle, the second beveled surface abuts against the limiting boss; the beneficial effect of this preferred embodiment is that it provides a double-safety hard limiting mechanism, precisely defining the maximum extension angle of the expanding piece. When the expanding piece rotates to this angle, the second beveled surface and the limiting boss fit tightly together, not only preventing further rotation, but also effectively transferring the external load to the anchor head body through this contact surface, greatly enhancing the load-bearing capacity and rigidity of the entire anchor head under maximum working conditions.

[0013] Preferably, the expansion joint consists of two pieces, symmetrically arranged on both sides of the anchor head body; the inner connecting section has a shaft hole, and the anchor head body has a rotating shaft that passes through the shaft hole and has limiting components at both ends; the advantages of this preferred design are that the symmetrical double expansion joint design has a simple structure, balanced force distribution, and can provide symmetrical radial support force, preventing the anchor head from tilting within the hole. The rotating shaft connection method allows for flexible rotation and high reliability. The limiting components prevent the expansion joints from falling off the rotating shaft, ensuring the product's service life and safety.

[0014] Preferably, the limiting component includes a limiting plate and a limiting pin; the anchor head body is also provided with an elastic retaining plate, one end of which is fixed to the anchor head body, and the other end cooperates with the friction enhancement structure on the outer anchoring section of the expansion joint; the beneficial effect of this preferred embodiment is that the limiting plate and the limiting pin provide simple and reliable axial fixation. The key function of the elastic retaining plate is: before installation, it applies a preload to the expansion joint to keep it in a contracted state, facilitating insertion into the borehole; after installation, it can open along with the expansion joint and continuously press against its outer surface, playing a role in preventing loosening, reducing vibration, and assisting in anchoring, further enhancing the reliability of the anchoring.

[0015] Preferably, the elastic retaining piece is a spring clip structure, including a central portion that fits against the outer surface of the closed end, and fastening wings on both sides of the central portion, the ends of which are engaged with a friction-enhancing structure. The advantages of this preferred embodiment are that the spring clip structure is simple, has good elasticity, and is easy to manufacture and install; the central portion provides stable support, and the fastening wings on both sides can simultaneously and symmetrically press the two symmetrical expansion pieces, ensuring a balanced force on the expansion pieces, making their closing and opening actions more synchronized and stable; at the same time, it can prevent sand and gravel from entering the gap between the expansion piece and the anchor head body, affecting the smooth rotation of the expansion piece.

[0016] Preferably, there are 3-5 expansion joints, which are pivotally connected around the closed end at even intervals; the end of the inner connecting section of the expansion joint is set as a spherical surface; the beneficial effect of this preferred option is that by setting this number of expansion joints, the connection strength is guaranteed, and the anchoring effect is better through more support points. Attached Figure Description

[0017] Figure 1 This is a front view schematic diagram of a large-angle expansion shell anchor head for loose rock strata, according to an embodiment of the utility model.

[0018] Figure 2 This is an isometric schematic diagram of the anchor head column of the large-angle expansion shell anchor head according to an embodiment of the utility model.

[0019] Figure 3 for Figure 1 A side sectional view.

[0020] Figure 4 This is a front view of the expansion plate of the large-angle expansion shell anchor head according to an embodiment of the utility model.

[0021] Figure 5 This is a side sectional view of the anchor head column of the large-angle expansion shell anchor head according to an embodiment of the present invention.

[0022] Figure 6 This is a cross-sectional view of the anchor head column of the large-angle expansion shell anchor head according to an embodiment of the present invention.

[0023] Figure 7This is an isometric view of the expansion plate of the large-angle expansion shell anchor head according to an embodiment of the present invention.

[0024] Figure 8 This is a front view of the large-angle expansion shell anchor head with spring sheet according to an embodiment of the present invention.

[0025] Figure 9 This is a schematic diagram showing the interaction between the large-angle expansion anchor head and the rock wall in an embodiment of the present invention at the maximum opening angle.

[0026] Explanation of reference numerals in the attached figures: Anchor head body 1, threaded interface 101, closed end 102, mounting groove 103, first oblique surface 104, limiting boss 105, rotating shaft 106, expansion plate 2, inner connecting section 201, outer anchoring section 202, friction enhancement structure 203, inclined guide surface 204, arc-shaped structure 205, second oblique surface 206, shaft hole 207, limiting component 208, limiting plate 209, limiting pin 210, central part 301, fastening wing 302. Detailed Implementation

[0027] The preferred embodiments of this utility model will now be described in detail with reference to the accompanying drawings, so that the advantages and features of this utility model can be more easily understood by those skilled in the art, thereby providing a clearer and more definite definition of the scope of protection of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model. Example 1:

[0028] like Figure 1-8 As shown: A large-angle expanding shell anchor head for anchoring loose rock strata includes an anchor head body 1 and multiple tensioning components disposed around its circumference. Specifically, the anchor head body 1 has an axial inner cavity in the middle, with a threaded interface 101 for connecting the anchor rod at the bottom end and a closed end 102 at the top. The tensioning components include expanding plates 2, which include an inner connecting section 201 near the axis of the anchor head body 1 and an outer anchoring section 202 located outside the axis of the anchor head body 1 for contacting the rock strata. The inner connecting section 201 is pivotally connected to the closed end 102. The expanding plates 2 can rotate outward from the initial contracted state under the action of the axial thrust of the anchor rod, and when the set maximum unfolding angle is reached, they form a self-locking structure by the inner connecting sections 201 of each expanding plate 2 fitting together.

[0029] In implementation, the circumferential outer wall of the anchor head body 1 is provided with multiple first oblique cut surfaces 104, and each first oblique cut surface 104 has an installation groove 103. The installation groove 103 is located at the connection between the first oblique cut surface 104 and the closed end 102. The expansion piece 2 is assembled onto the anchor head body 1 through the rotating shaft 106 on the installation groove 103, and the edge of the inner connecting section 201 of the expansion piece 2 is in contact with the first oblique cut surface 104. The width of the installation groove 103 at the top of the closed end 102 is greater than the width of the threaded interface 101 side, i.e., the bottom. The outer anchoring section 202... The surface is provided with several friction-enhancing structures 203, specifically friction protrusions; the outer surface of the outer anchoring section 202 is provided with several friction-enhancing structures 203 at even intervals; the inclined first bevel surface 104 provides a natural guide and initial angle for the rotation of the expansion piece 2, making its unfolding process smoother; the width difference caused by the first bevel surface 104 facilitates better accommodation of the expansion piece 2 and better fit with the structure of the expansion piece 2; through the layout of the mounting groove 103, structural interference with the anchor head body 1 is avoided, facilitating large-angle expansion.

[0030] During implementation, when the expansion plates 2 are in their initial retracted state, the inner connecting sections 201 of each expansion plate 2 fit together, and an inclined guide surface 204 is integrally formed on the side near the threaded interface 101. The inclined guide surfaces 204 of multiple expansion plates 2 constitute a guide space for accommodating and guiding the end of the anchor rod. The inclined guide surface 204 can guide the end of the anchor rod to insert into and contact the expansion plate 2 more smoothly, efficiently transferring the axial thrust to the expansion plate 2, reducing the resistance during insertion and the impact on the components, and improving the installation efficiency.

[0031] In implementation, the top end of the inner connecting section 201 is an arc-shaped structure 205, wherein the arc-shaped structure 205 is a circular arc. During the rotation of the expansion piece 2, the arc-shaped structures 205 of multiple inner connecting sections 201 abut against each other during rotation; the setting of the arc-shaped structure 205 makes the rotation of the expansion piece 2 smoother; in specific implementation, a limiting boss 105 is integrally formed at the bottom of the closed end 102, and a second oblique surface 206 that cooperates with the limiting boss 105 is integrally formed on the inner connecting section 201 of the expansion piece 2; when When the expansion piece 2 is extended to its maximum angle, the second oblique surface 206 abuts against the limiting boss 105. The arc-shaped structure 205 and the limiting boss 105 provide a double-safety hard limiting mechanism, which precisely defines the maximum extension angle of the expansion piece. When the expansion piece 2 rotates to its maximum angle, the second oblique surface 206 and the limiting boss 105 fit tightly together, which not only prevents further rotation, but also effectively transmits the external load to the anchor head body through the fitting surface, greatly enhancing the load-bearing capacity and rigidity of the entire anchor head under maximum working conditions.

[0032] In implementation, the expansion plates 2 consist of two pieces, symmetrically arranged on the left and right sides of the anchor head body 1. A shaft hole 207 is provided in the inner connecting section 201, and a rotating shaft 106 is provided on the anchor head body 1. This rotating shaft 106 passes through the shaft hole 207 and has limiting members 208 at both ends. The symmetrical double expansion plate 2 design is simple in structure, provides balanced force, and can offer symmetrical radial support, preventing the anchor head from tilting within the hole. The rotating shaft connection method allows for flexible rotation and high reliability; the limiting members 208 prevent the expansion plates from falling off the rotating shaft, ensuring the product's service life and safety.

[0033] In implementation, the limiting component 208 includes a limiting plate 209 and a limiting pin 210; the anchor head body 1 is also provided with an elastic retaining plate 3, one end of which is fixed to the anchor head body 1, and the other end cooperates with the friction enhancement structure 203 on the outer anchoring section 202 of the expansion piece 2; wherein, the limiting plate and the limiting pin provide simple and reliable axial fixation; and are staggered on the corresponding expansion pieces 2, the key function of the elastic retaining plate 3 is: before installation, it applies a pre-tightening force to the expansion piece 2 to keep it in a contracted state, making it easy to insert into the borehole; after installation, it can open with the expansion piece and continuously press its outer surface, playing the roles of anti-loosening, vibration reduction and auxiliary anchoring. This further enhances the reliability of the anchoring. Specifically, the elastic retaining piece 3 is a spring clip structure, including a central part 301 that fits against the outer surface of the closed end 102. The central part 301 has fastening wings 302 on both sides, and the ends of the fastening wings 302 are engaged with the friction enhancement structure 203. The spring clip structure is simple, has good elasticity, and is easy to manufacture and install. The central part 301 provides stable support, and the fastening wings 302 on both sides can simultaneously and symmetrically press the two symmetrical expansion pieces, ensuring that the force on the expansion pieces is balanced, making their closing and opening actions more synchronous and stable. It can also shield and protect the position of the expansion piece rotation connection, ensuring the smooth rotation of the expansion piece.

[0034] The specific implementation principle is as follows: Before the anchor head is inserted into the anchor hole, each expansion piece 2 is in a closed state; at this time, each inner connecting section 201 is closely fitted together, with a slender overall profile, making it easy to insert into the pre-drilled anchor hole with a larger diameter in the loose rock layer; through the rotation of the hollow anchor rod, the continuous spiraling action is converted into a thrust on the expansion piece 2; since the expansion piece 2 is connected to the closed end through a pivotal connection, this thrust will force the expansion piece to rotate outward around the axis of rotation, rather than sliding axially; as the expansion piece 2 continues to rotate, its opening angle continuously increases, which is very suitable for the large opening angle required by the loose rock layer; when rotated to the set maximum angle, the sides of the inner connecting sections 201 of each expansion piece 2 are tightly fitted together and work together to form the closed end. It forms a stable self-locking structure; this structure can effectively resist the closing tendency brought about by the reaction force of the rock strata, solving the problem that traditional sliding structures may shrink back in loose rock strata; in practical applications, the fully opened and self-locking expansion piece 2 will destroy the rock strata and invade the rock strata. The friction enhancement structure on the outer anchoring section 202 has been firmly pressed against the rock strata of the anchor hole wall. At this time, the anchor rod is pulled back, and the entire device enters a high-strength anchoring state; because it is mechanically self-locking and forms a constraint limit with the rock strata after invasion, its pull-out resistance and strength far exceed those of traditional anchor heads that rely solely on friction. When applied to relatively soft rock strata, its anchor head end has a larger volume, and after grouting reinforcement, it forms a larger anchor head with better strength. Example 2:

[0035] The difference between this embodiment and Embodiment 1 is that, Figure 9 In this scheme, there are 3-5 expansion plates 2, specifically 3, which are evenly spaced and pivotally connected around the circumference of the closed end 102; the end of the inner connecting section 201 of the expansion plate 2 is set as a spherical surface; by setting this number of expansion plates 2, while ensuring the connection strength, more support points with the anchor hole are provided, and the anchoring effect is better.

[0036] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims.

Claims

1. A large-angle expansion-shell type anchor head for anchoring loose rock strata, comprising an anchor head body (1) and a plurality of tensioning components disposed circumferentially thereon; the anchor head body (1) is provided with an axial inner cavity, one end of which is provided with a threaded interface (101) for connecting an anchor rod, and the other end is a closed end (102); characterized in that: The tensioning assembly includes a tension plate (2), which includes an inner connecting section (201) near the axis of the anchor head body (1) and an outer anchoring section (202) for contacting the rock strata; the inner connecting section (201) is pivotally connected to the closed end (102); the tension plate (2) can rotate outward from the initial retracted state under the action of the axial thrust of the anchor rod, and when the set maximum unfolding angle is reached, the inner connecting sections (201) of each tension plate (2) fit together to form a self-locking structure.

2. The large-angle expansion shell anchor head for anchoring loose rock strata according to claim 1, characterized in that: The circumferential outer wall of the anchor head body (1) is provided with a plurality of first oblique cut surfaces (104), and each first oblique cut surface (104) is provided with an installation groove (103). The expansion piece (2) is rotatably connected to the anchor head body (1) through the installation groove (103). The edge of the inner connecting section (201) of the expansion piece (2) is in contact with the first oblique cut surface (104). The width of the installation groove (103) on the closed end (102) side is greater than the width on the threaded interface (101) side. The outer surface of the outer anchoring section (202) is provided with a plurality of friction enhancement structures (203).

3. The large-angle expansion shell anchor head for anchoring loose rock strata according to claim 1, characterized in that: In the initial retracted state, the inner connecting sections (201) of each expansion piece (2) fit together, and an inclined guide surface (204) is provided on the side near the threaded interface (101). The inclined guide surfaces (204) of the multiple expansion pieces constitute a guide space for accommodating and guiding the end of the anchor rod.

4. The large-angle expansion shell anchor head for anchoring loose rock strata according to claim 1, characterized in that: The end of the inner connecting section (201) is an arc-shaped structure (205). During the rotation of the expansion piece (2), the arc-shaped structures (205) of multiple inner connecting sections (201) abut against each other when rotating.

5. The large-angle expansion shell anchor head for anchoring loose rock strata according to claim 4, characterized in that: The inner side of the closed end (102) is provided with a limiting boss (105), and the inner connecting section (201) of the expansion piece (2) is provided with a second oblique surface (206) that cooperates with the limiting boss (105); when the expansion piece (2) is unfolded to the maximum angle, the second oblique surface (206) abuts against the limiting boss (105).

6. The large-angle expansion shell anchor head for anchoring loose rock strata according to claim 1, characterized in that: The expansion piece (2) consists of two pieces, symmetrically arranged on both sides of the anchor head body (1); the inner connecting section (201) is provided with a shaft hole (207), and the anchor head body (1) is provided with a rotating shaft (106), which passes through the shaft hole (207) and has limiting parts (208) at both ends.

7. The large-angle expansion shell anchor head for anchoring loose rock strata according to claim 6, characterized in that: The limiting component (208) includes a limiting plate (209) and a limiting pin (210); the anchor head body (1) is also provided with an elastic retaining plate (3), one end of which is fixed to the anchor head body (1), and the other end is engaged with the friction enhancement structure (203) on the outer anchoring section (202) of the expansion plate (2).

8. The large-angle expansion shell anchor head for anchoring loose rock strata according to claim 7, characterized in that: The elastic retaining piece (3) is a spring clip structure, including a central part (301) that fits against the outer surface of the closed end (102), and fastening wings (302) on both sides of the central part (301), the ends of which are engaged with the friction enhancement structure (203).

9. The large-angle expansion shell anchor head for anchoring loose rock strata according to claim 1, characterized in that: The expansion piece (2) has 3 to 5 pieces, which are pivotally connected around the closed end (102) at even intervals.

10. The large-angle expansion shell anchor head for anchoring loose rock strata according to claim 9, characterized in that: The end of the inner connecting section (201) of the expansion piece (2) is set as a spherical surface.

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