A kind of automatic tightening tool for secondary tensioning pressure-bearing nuts of low retraction anchor

Abstract

The present invention relates to the field of prestressed anchors, and in particular to an automatic tightening tool for secondary tensioning pressure nuts of low-shrinkage anchors, which is used for tightening the pressure nuts of low-shrinkage anchors, wherein the pressure nuts are arranged in deep buried grooves of beam concrete, and include tensioning stools, which are arranged on the beam concrete; the tensioning stools include panels and legs, a prestressed bundle passing hole is provided at one end of the panel and at the center, and two groups of legs are fixedly connected in a rectangular shape at the bottom end of the panel, and both groups of legs are located on the outside of the prestressed bundle passing hole; a torsion sleeve is connected to the end of the panel close to the leg through a torsion track, and an inner lining sleeve is connected to the inner wall of the torsion sleeve and the side away from the panel, and the inner wall of the lining sleeve is connected to the outer surface of the pressure nut; in the present invention, the pressure nut is tightened automatically, which reduces manual operation, eliminates human deviation, reduces construction errors, and thus ensures the quality of prestressed construction.

Description

Technical Field

[0001] The invention relates to the field of prestressed anchors, and in particular to an automatic tightening tool for secondary tensioning pressure-bearing nuts of low-retraction anchors. Background Art

[0002] Low-retraction anchor is a kind of low-retraction and high-efficiency prestressed anchor specially developed to solve the problem that the prestressed anchor has too large retraction during tensioning and releasing, which leads to large loss of effective permanent prestress. It is widely used in vertical prestressed structures of bridges such as large-span prestressed concrete continuous beams and continuous steel structures. The national standard stipulates that the retraction of the anchor should not exceed 5mm. In practice, the compression of the anchor itself is less than 5mm, but the retraction of the steel strand is generally around 8mm, sometimes more than 8mm. The amount of retraction of the steel strand depends on whether the clip is followed up in time. The retraction of the steel strand of the low-retraction anchor is only 0-0.2mm, which makes the low-retraction anchor and the pressure-bearing nut structure achieve the purpose of good self-locking performance, reliable anchoring, small retraction and small prestress loss.

[0003] At present, in the actual on-site operation process, there is no complete set of standard tooling for tightening pressure nuts. Pressure nuts are generally tightened manually using a tightening wrench, and the installation of low-retraction anchors generally adopts a deep buried method. The anchor ring and the pressure nut are generally in a deep buried groove, which brings inconvenience to the tightening of the pressure nut in construction; some existing secondary tensioning tooling for low-retraction anchors only solves the problem that the deep buried groove brings inconvenience to the tensioning work. The pressure nut still needs to be tightened manually. There is no uniform standard for the tightening torque of the pressure nut. The manual operation is relatively random, which inevitably leads to human deviation. The tightening quality of the pressure nut is uneven and the construction error is large. Summary of the invention

[0004] The purpose of the present invention is to provide an automatic tightening tool for secondary tensioning pressure-bearing nuts of low-retraction anchors, which mainly solves the technical problems raised in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An automatic tightening tool for secondary tensioning pressure-bearing nuts of low-retraction anchors, used for tightening pressure-bearing nuts of low-retraction anchors, wherein the pressure-bearing nuts are arranged in deep buried grooves of beam concrete, and include tensioning support stools, wherein the tensioning support stools are arranged on the beam concrete;

[0007] The tensioning stool comprises a panel, one end of the panel is provided with a prestressed bundle through hole at the center, the bottom end of the panel is rectangular and fixedly connected with two groups of legs, and the two groups of legs are both located outside the prestressed bundle through hole;

[0008] One end of the panel close to the leg is connected to a torsion sleeve through a torsion track, an inner wall of the torsion sleeve and a side away from the panel is connected to a lining sleeve, and the inner wall of the lining sleeve is connected to the outer surface of the pressure nut;

[0009] The torsion track is configured as an annular structure, and the torsion track is sequentially provided with an inner fixed ring, a rotating ring and an outer fixed ring from the inside to the outside, the rotating ring is rotatably connected between the inner fixed ring and the outer fixed ring, the top ends of the inner fixed ring and the outer fixed ring are respectively fixedly connected to the bottom end of the panel, and the bottom end of the rotating ring is fixedly connected to the top end of the torsion sleeve;

[0010] The outer surface of the outer fixed ring is fixedly connected to a torsion motor, the output end of the torsion motor is fixedly connected to a gear, the outer surface of the rotating ring is provided with an annular tooth profile, the outer side of the gear passes through the outer surface of the outer fixed ring and meshes with the inner wall of the tooth profile.

[0011] Preferably, a through-hole jack is provided at the top of the panel, and the central axis of the through-hole jack coincides with the central axis of the prestressed bundle passing hole.

[0012] Preferably, a tool anchor is provided at one end of the through-hole jack away from the panel.

[0013] Preferably, an anchor plate is screwed onto the inner wall of the pressure-bearing nut, and anchor rings are fixedly connected to the top and bottom of the anchor plate.

[0014] Preferably, the two groups of legs include two parallel first legs and two parallel second legs, the ends of the first legs and the second legs close to each other and the end of the second legs away from the panel are reserved with an observation window. The fixed connection encloses to form a rectangle, and the end of the second legs away from the panel is reserved with an observation window.

[0015] An intelligent control switch box is fixedly connected to the outer surface of the first leg, an intelligent control panel is arranged inside the intelligent control switch box, an intelligent control switch is arranged outside the intelligent control switch box for operating the intelligent control panel to start the torsion motor, and the intelligent control panel is electrically connected to the torsion motor and the intelligent control switch respectively.

[0016] Preferably, the bottom end of the inner wall of the torsion sleeve is evenly provided with a plurality of primary tongue and grooves along a ring shape;

[0017] A plurality of primary tenons are evenly arranged along a ring at the bottom end of the outer surface of the liner sleeve, and the positions and sizes of the plurality of primary tenons are respectively adapted to the positions and sizes of the plurality of primary tenons.

[0018] Preferably, a plurality of secondary tongue and grooves are evenly formed along a ring shape on the top of the outer surface of the pressure-bearing nut;

[0019] A plurality of secondary tenons are evenly arranged along a ring at the top end of the inner wall of the lining sleeve, and the positions and sizes of the plurality of secondary tenons are respectively adapted to the positions and sizes of the plurality of secondary tenons.

[0020] Preferably, the number and size of the primary tenons are the same as those of the secondary tenons, and the widths of the primary tenons and the secondary tenons are both set to 5 mm, and the heights are both set to 15 mm.

[0021] Preferably, the number and size of the primary mortise and tenon grooves are the same as those of the secondary mortise and tenon grooves, and the widths of the primary mortise and tenon grooves and the secondary mortise and tenon grooves are both set to 7 mm, and the heights are both set to 15 mm.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. In the present invention, the pressure-bearing nut is tightened automatically, which reduces manual operation, eliminates human deviation, reduces construction errors, and thus ensures the quality of prestressed construction.

[0024] 2. In the present invention, the pressure-bearing nut, the lining sleeve, and the torsion sleeve are connected by a mortise and tenon structure, which is easy to install. The cross-sectional size of the mortise and tenon structure is small, and there is no need to drill holes on the pressure-bearing nut, thereby ensuring the structural integrity of the pressure-bearing nut.

[0025] 3. In the present invention, before the start of the secondary prestressing, the lining sleeve and the torsion sleeve are installed in place in sequence along with the tensioning support bench. During the prestressing and tightening of the pressure nut, there is no need for personnel to operate under the tensioning support bench, thereby ensuring the safety of the tensioning operators. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 This is a structural diagram of an automatic tightening tooling for secondary tensioning pressure-bearing nuts of a low-retraction anchor of the present invention;

[0028] Figure 2 For the present invention Figure 1 A magnified image of point A;

[0029] Figure 3 For the present invention Figure 1 A stereogram of the torsion orbit;

[0030] Figure 4 For the present invention Figure 1 A three-dimensional diagram of a pressure nut;

[0031] Figure 5 For the present invention Figure 1 A three-dimensional view of an inner liner sleeve;

[0032] Figure 6 For the present invention Figure 1 A three-dimensional view of a torsion sleeve;

[0033] Figure 7 For the present invention Figure 1 Installation diagram of the pressure nut, liner sleeve and torsion sleeve;

[0034] Figure 8 For the present invention Figure 1 A three-dimensional image of a tensioned stool.

[0035] In the figure: a tensioning support stool 1, a panel 101, a prestressed beam through hole 1011, a first leg 102, a second leg 103, an observation window 104, an intelligent control switch box 2, a torsion motor 3, a gear 31, a torsion track 4, an inner fixed ring 41, a rotating ring 42, a tooth profile 421, an outer fixed ring 43, a torsion sleeve 5, a primary mortise and tenon 51, a pressure nut 6, a secondary mortise and tenon 61, an inner lining sleeve 7, a primary tenon 71, a secondary tenon 72, an anchor plate 8, an anchor ring 9, a through jack 10, a tool anchor 11, a steel strand 12, a beam concrete 13, a deep buried groove 131, and a tool clip 14. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] like Figure 1-8As shown, the present invention provides an automatic tightening tool for secondary tensioning pressure nuts of low-retraction anchors, which is used to tighten the pressure nuts 6 of low-retraction anchors. The pressure nuts 6 are arranged in the deep buried groove 131 of the beam concrete 13, and include a tensioning support stool 1, which is arranged on the beam concrete 13; the tensioning support stool 1 includes a panel 101 and legs, and the legs and the panel 101 are both made of 20mm thick steel plates. A prestressed beam passing hole 1011 with a diameter of Ф≥50mm is opened at one end of the panel 101 and at the center. The bottom end of the panel 101 is rectangular and fixedly connected with two groups of legs, and the two groups of legs are located on the outside of the prestressed beam passing hole 1011; the end of the panel 101 close to the legs is connected to a torsion sleeve 5 through a torsion track 4, and the inner wall of the torsion sleeve 5 and the side away from the panel 101 are connected to an inner lining sleeve 7, and the inner wall of the inner lining sleeve 7 is connected to the outer surface of the pressure nut 6;

[0038] The torsion track 4 is set as an annular structure, and the torsion track 4 is sequentially provided with an inner fixed ring 41, a rotating ring 42 and an outer fixed ring 43 from the inside to the outside, and the rotating ring 42 is rotatably connected between the inner fixed ring 41 and the outer fixed ring 43, and the top ends of the inner fixed ring 41 and the outer fixed ring 43 are respectively fixedly connected to the bottom end of the panel 101, and the bottom end of the rotating ring 42 is fixedly connected to the top end of the torsion sleeve 5; wherein, the torsion track 4 limits the horizontal displacement of the torsion sleeve 5 and allows the vertical displacement of the torsion sleeve 5, and the displacement amount is: 1-15mm, so as to meet the tightening displacement of the pressure nut 6; the outer surface of the outer fixed ring 43 is fixedly connected to the torsion motor 3, and the output end of the torsion motor 3 is fixedly connected There is a gear 31, and the outer surface of the rotating ring 42 is provided with an annular tooth profile 421. The outer side of the gear 31 passes through the outer surface of the outer fixed ring 43 and meshes with the inner wall of the tooth profile 421. When in use, the torsion motor 3 is started, so that the torsion motor 3 drives the gear 31 to rotate, and then the gear 31 drives the rotating ring 42 to rotate along the inner and outer fixed rings, and then the rotating ring 42 drives the torsion sleeve 5, the lining sleeve 7 and the pressure nut 6 to rotate synchronously in turn, so as to automatically tighten the pressure nut 6. It can reduce manual operation, eliminate human deviation, reduce construction errors, ensure the tightening quality of the pressure nut 6, and thus ensure the quality of bridge prestressing construction.

[0039] Specifically, a through-hole jack 10 is provided at the top of the panel 101 , and the central axis of the through-hole jack 10 coincides with the central axis of the prestressed bundle through hole 1011 , so as to apply tension to the steel strand 12 .

[0040] Specifically, a tool anchor 11 is provided at one end of the through-hole jack 10 away from the panel 101 . When the steel strand 12 passes through the tool anchor 11 , the tool clip 14 is inserted into the tool anchor 11 along the outer surface of the steel strand 12 to clamp and fix the steel strand 12 .

[0041] Specifically, an anchor plate 8 is screwed onto the inner wall of the pressure-bearing nut 6, and anchor rings 9 are fixedly connected to opposite sides of the anchor plate 8 for prestressing.

[0042] Specifically, the two groups of legs include two parallel first legs 102 and two parallel second legs 103. The ends of the first legs 102 and the second legs 103 close to each other are fixedly connected to form a rectangle, and the first legs 102 serve as the main load-bearing structure, and the steel plate adopts a full-section form; an observation window 104 is reserved at the lower part of the second leg 103 to ensure a stable connection; the first legs 102 and the second legs 103 are respectively connected to the inner and outer connections of the panel 101 with 10 mm thick steel plates as reinforcing plates to increase the rigidity, integrity and stability of the tensioned support stool 1; all parts of the tensioned support stool 1 are connected by double-sided welding.

[0043] Specifically, the outer surface of the first leg 102 is fixedly connected to an intelligent control switch box 2, and an intelligent control panel is provided in the intelligent control switch box 2. An intelligent control switch is provided outside the intelligent control switch box 2 for operating the intelligent control panel to start the torsion motor 3, and the intelligent control panel is electrically connected to the torsion motor 3 and the intelligent control switch respectively; before use, the user can set the tightening torque through the intelligent control panel according to the use requirements, which is used to control the torsion motor 3, so as to facilitate the automatic tightening of the tooling.

[0044] Specifically, the torsion sleeve 5 is made of DN150 hot-rolled seamless steel pipe (wall thickness ≥10mm), and its length is determined according to the depth of the tensioning support stool 1 and the deep buried groove 131, and a plurality of first-level mortise and tenon grooves 51 are evenly arranged along a ring at the bottom end of the inner wall of the torsion sleeve 5; a plurality of first-level tenons 71 are evenly arranged along a ring at the bottom end of the outer surface of the lining sleeve 7, and the positions and sizes of the plurality of first-level tenons 71 are respectively adapted to the positions and sizes of the plurality of first-level mortise and tenon grooves 51; and they are used to position and install the torsion sleeve 5 and the lining sleeve 7.

[0045] Specifically, a plurality of secondary tenons 61 are evenly arranged along a ring at the top end of the outer surface of the pressure-bearing nut 6; a plurality of secondary tenons 72 are evenly arranged along a ring at the top end of the inner wall of the lining sleeve 7, and the positions and sizes of the plurality of secondary tenons 72 are respectively adapted to the positions and sizes of the plurality of secondary tenons 61; and they are used for positioning and installing the pressure-bearing nut 6 and the lining sleeve 7.

[0046] Among them, the lining sleeve 7 is processed according to the on-site low-retraction anchor pressure nut 6, the height is set to 35 mm, and the diameter and wall thickness are determined according to the gap width between the pressure nut 6 and the torsion sleeve 5.

[0047] Specifically, the number and size of the primary tenons 71 and the secondary tenons 72 are the same, and the width of the primary tenons 71 and the secondary tenons 72 are both set to 5 mm, and the height is both set to 15 mm.

[0048] Specifically, the number and size of the primary tenon grooves 51 and the secondary tenon grooves 61 are the same, and the width of the primary tenon grooves 51 and the secondary tenon grooves 61 are both set to 7 mm, and the height is both set to 15 mm.

[0049] Among them, the use method of automatic tightening tooling is:

[0050] The first tensioning of low retraction anchor: The first tensioning is carried out in accordance with the requirements of conventional anchor tensioning. Before tensioning, the pressure nut 6 is screwed upwards away from the anchor pad 8 to 1mm-2mm. The second tensioning construction is carried out within 2-16 hours after the first tensioning is completed.

[0051] Second tensioning of low retraction anchor: install lining sleeve 7 → install tensioning support stool 1 → install through-hole jack 10 → install tool anchor 11 → prestressing → turn on intelligent control switch → intelligent control switch automatically turns off → tensioning completed, release and remove tooling.

[0052] The specific installation process is as follows:

[0053] Install the lining sleeve 7: install the secondary tenons 72 on the lining sleeve 7 in one-to-one correspondence with the secondary tenons 61 on the pressure nut 6.

[0054] Installing the tensioning support stool 1: the torsion sleeve 5 and the tensioning support stool 1 are connected as a whole through the torsion track 4, so that the torsion sleeve 5 can be installed at the same time as the tensioning support stool 1, and the first-level mortise 51 on the torsion sleeve 5 and the first-level tenon 71 on the lining sleeve 7 are installed one by one; and during the installation process, the installation position can be observed through the observation window 104 reserved on the tensioning support stool 1 to avoid the occurrence of improper installation; finally, the steel strand 12 can be passed through the prestressed bundle through hole 1011 on the panel 101 of the tensioning support stool 1.

[0055] Install the through-hole jack 10: pass the steel strand 12 through the through-hole jack 10.

[0056] Install the tool anchor 11: After the steel strand 12 passes through the tool anchor 11, the tool clip 14 is inserted into the tool anchor 11 to fix the steel strand 12.

[0057] Prestressing tensioning: The prestressing steel strand together with the anchor ring 9 is tensioned to 1.03δcon, so that the lower end surface of the anchor ring 9 located above the anchor plate 8 is 5 to 13 mm away from the anchor plate 8 and the load is maintained for 2 minutes.

[0058] Turn on the intelligent control switch: pre-set the tightening torque, turn on the intelligent control switch, and the torsion motor 3 drives the torsion sleeve 5 through the torsion track 4 to start working.

[0059] The intelligent control switch automatically closes: when the tightening torque reaches the set torque, the intelligent control switch automatically closes and the pressure nut 6 is tightened into place.

[0060] After the tensioning is completed, the tooling is released and removed: After the pressure-bearing nut 6 is tightened, the second tensioning is completed, the prestressed tendons are released, and the tooling is removed in reverse order according to the second tensioning process of the low-shrinkage anchor, and the anchor is sealed by grouting.

[0061] As a further optimization of this embodiment, a data storage device may be provided inside the intelligent control switch box 2 , and a digital display screen may be provided outside the intelligent control switch box 2 , which may record and display the final tightening torque of the pressure nut 6 .

[0062] As a further optimization of this embodiment, the tensioned support stool 1 can adjust the arrangement and height of the support stool legs according to the plane size and depth of the deep buried groove 131 on site.

[0063] As a further optimization of this embodiment, the contact surface between the lining sleeve 7 and the pressure-bearing nut 6 can be customized according to the size of the low-retraction anchor pressure-bearing nut 6 produced by different manufacturers.

[0064] As a further optimization of this embodiment, the legs and torsion sleeve 5 of the tensioning stool 1 can be made into retractable devices to solve the problem of inconsistent reserved lengths of the on-site steel strands 12 and the depths of the deep buried grooves 131.

[0065] As a further optimization of this embodiment, friction material can be added to the support pad under the first leg 102 (the main load-bearing leg) of the tensioning stool 1 to ensure that the friction between the tensioning stool 1 and the bridge deck is sufficient to resist the tightening torque of the pressure nut 6.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An automatic tightening tool for secondary tensioning pressure nuts of low retraction anchors, used for tightening the pressure nuts (6) of low retraction anchors, wherein the pressure nuts (6) are arranged in a deep buried groove (131) of beam concrete (13), characterized in that: It comprises a tensioning support stool (1), wherein the tensioning support stool (1) is arranged on the beam body concrete (13); The tensioning stool (1) comprises a panel (101), one end of the panel (101) is provided with a prestressed bundle through hole (1011) at the center, the bottom end of the panel (101) is rectangular and fixedly connected with two groups of legs, and the two groups of legs are located outside the prestressed bundle through hole (1011); The end of the panel (101) close to the leg is connected to a torsion sleeve (5) via a torsion track (4); the inner wall of the torsion sleeve (5) and the side away from the panel (101) is connected to an inner lining sleeve (7); the inner wall of the inner lining sleeve (7) is connected to the outer surface of the pressure nut (6); The torsion track (4) is arranged in an annular structure, and the torsion track (4) is provided with an inner fixed ring (41), a rotating ring (42) and an outer fixed ring (43) in sequence from the inside to the outside, the rotating ring (42) is rotatably connected between the inner fixed ring (41) and the outer fixed ring (43), the top ends of the inner fixed ring (41) and the outer fixed ring (43) are respectively fixedly connected to the bottom ends of the panel (101), and the bottom end of the rotating ring (42) is fixedly connected to the top end of the torsion sleeve (5); The outer surface of the outer fixed ring (43) is fixedly connected to a torsion motor (3), the output end of the torsion motor (3) is fixedly connected to a gear (31), the outer surface of the rotating ring (42) is provided with an annular tooth profile (421), and the outer side of the gear (31) passes through the outer surface of the outer fixed ring (43) and meshes with the inner wall of the tooth profile (421); The bottom end of the inner wall of the torsion sleeve (5) is evenly provided with a plurality of primary tongue and tongue grooves (51) along a ring shape; A plurality of primary tenons (71) are evenly arranged in a ring shape at the bottom end of the outer surface of the lining sleeve (7), and the positions and sizes of the plurality of primary tenons (71) are respectively adapted to the positions and sizes of the plurality of primary tenons (51).

2. The automatic tightening tool for secondary tensioning pressure-bearing nuts of low retraction anchors according to claim 1 is characterized by: A through-hole jack (10) is provided at the top end of the panel (101), and the central axis of the through-hole jack (10) coincides with the central axis of the prestressed bundle through hole (1011).

3. The automatic tightening tool for secondary tensioning pressure-bearing nuts of low retraction anchors according to claim 2 is characterized by: A tool anchor (11) is provided at one end of the through-hole jack (10) away from the panel (101).

4. The automatic tightening tool for secondary tensioning pressure-bearing nuts of low retraction anchors according to claim 1 is characterized by: An anchor plate (8) is screwed onto the inner wall of the pressure-bearing nut (6), and anchor rings (9) are fixedly connected to the top and bottom of the anchor plate (8).

5. The automatic tightening tool for secondary tensioning pressure-bearing nuts of low retraction anchors according to claim 1 is characterized by: The two groups of legs include two parallel first legs (102) and two parallel second legs (103); the first legs (102) and the second legs (103) are fixedly connected at their mutually adjacent ends to enclose a rectangle; an observation window (104) is reserved at one end of the second legs (103) away from the panel (101).

6. The automatic tightening tool for secondary tensioning pressure-bearing nuts of low retraction anchors according to claim 5 is characterized by: The outer surface of the first leg (102) is fixedly connected to an intelligent control switch box (2), an intelligent control panel is provided inside the intelligent control switch box (2), an intelligent control switch is provided outside the intelligent control switch box (2), and is used to operate the intelligent control panel to start the torsion motor (3), and the intelligent control panel is electrically connected to the torsion motor (3) and the intelligent control switch, respectively.

7. The automatic tightening tool for secondary tensioning pressure-bearing nuts of low retraction anchors according to claim 1 is characterized by: The top end of the outer surface of the pressure-bearing nut (6) is evenly provided with a plurality of secondary tongue and grooves (61) along a ring shape; A plurality of secondary tenons (72) are evenly arranged in a ring shape at the top end of the inner wall of the lining sleeve (7), and the positions and sizes of the plurality of secondary tenons (72) are respectively adapted to the positions and sizes of the plurality of secondary tenons (61).

8. The automatic tightening tool for secondary tensioning pressure-bearing nuts of low retraction anchors according to claim 7 is characterized by: The number and size of the primary tenons (71) and the secondary tenons (72) are the same, and the widths of the primary tenons (71) and the secondary tenons (72) are both set to 5 mm, and the heights are both set to 15 mm.

9. The automatic tightening tool for secondary tensioning pressure-bearing nuts of low retraction anchors according to claim 7 is characterized by: The number and size of the primary tenon groove (51) and the secondary tenon groove (61) are the same, and the width of the primary tenon groove (51) and the secondary tenon groove (61) are both set to 7 mm, and the height is both set to 15 mm.

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