Tensioning jack rear anchor type and front clamp type

Abstract

The invention relates to the technical field of prestressed beam tensioning, in particular to a tensioning jack rear anchor type and front clamp type replacement, which comprises a jack assembly, a front clamp anchorage device assembly and a box beam anchorage device assembly, the jack assembly comprises a cylinder body, a support cylinder is fixedly arranged at the end part of the cylinder body, a piston cylinder is movably connected to the middle of the support cylinder, and the front clamp anchorage device assembly is fixedly connected with the piston cylinder. A sealing seat is fixedly arranged at the end of the piston barrel, a first through groove is formed in the middle of the cylinder body, a sliding groove is formed in the cylinder body for the sealing seat to slide, and a first oil nozzle is connected to the side wall of the cylinder body in an inserted mode. Through cooperation of a jack assembly, a front clamping anchorage device assembly, a box girder anchorage device assembly, a first clamping piece assembly, a positioning assembly and a second clamping piece assembly, the outer surface of a piston barrel is sleeved with a supporting barrel for supporting a limiting cylinder body, and through cooperation of a limiting disc, the front clamping anchorage device assembly and a limiting nut, the arrangement distance between a second anchorage device disc and a first anchorage device disc is shortened; therefore, loss of the prestressed tendons is reduced, and production cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of prestressed beam tensioning, in particular to a tensioning jack which is changed from a rear anchor type to a front clamp type. Background Art

[0002] Prestressed concrete beam is a component widely used in bridges and other structures. Prestressed box beam is mainly used to improve the bearing capacity and crack resistance of the structure. Prestressed concrete beam: The prestressed tendons are prestressed in advance to generate negative bending moment in the span of the beam to partially offset the positive bending moment of the beam in use, thereby improving the performance of the beam. In the production process of prestressed concrete beams, anchors and jacks are required to tension the two ends of the prestressed tendons.

[0003] Prestressed concrete beam construction usually includes pre-tensioning and post-tensioning. The basic principle of the post-tensioning method is to insert the steel bars or steel strands (prestressed tendons) into the rubber of the box beam mold before pouring the concrete, and then pour it in the mold. After the concrete is completely solidified, the inserted prestressed tendons are tensioned. The anchors at both ends of the prestressed tendons are fixed at both ends of the box beam, and then sealed in the rubber pipe after tensioning. The post-tensioning method is opposite to the pre-tensioning method. It can be tensioned in the later stage of construction, which is convenient for controlling the application time and effect of prestressing. It is suitable for structures with large spans and complex shapes, causes less damage to concrete, helps to improve the overall performance of concrete, can be adjusted and reinforced in the later stage, and has high flexibility.

[0004] Existing tensioning jacks usually adopt the rear anchor type. During the tensioning process, the operator needs to clamp the rear anchor on the end of the jack. The output end of the jack is supported on the end of the box girder anchor in turn. The prestressed tendons need to pass through the middle of the jack cylinder and then connect the box girder anchor and the rear anchor. Since the rear anchor and the box girder anchor are far apart, the prestressed tendons are wasted after tensioning, which affects the production cost of the prestressed beam. Summary of the invention

[0005] Based on this, it is necessary to provide a tensioning jack that can be replaced by a front-clip type with a rear-anchor type in order to solve the existing technical problems.

[0006] In order to solve the problems of the prior art, the technical solution adopted by the present invention is:

[0007] The rear anchor type of the tensioning jack is changed to the front clamp type, including a jack assembly, a front clamp anchor assembly and a box beam anchor assembly. The jack assembly includes a cylinder body, an end of the cylinder body is fixedly provided with a support cylinder, the middle of the support cylinder is movably connected with a piston cylinder, the end of the piston cylinder is fixedly provided with a sealing seat, the middle of the cylinder body is provided with a through groove 1, the inside of the cylinder body is provided with a sliding groove for the sealing seat to slide, the side wall of the cylinder body is plugged into a first oil nozzle, the side wall of the cylinder body is plugged into a second oil nozzle on the side wall of the cylinder body close to the first oil nozzle, a connecting seat is fixedly provided on the inner side wall of the piston cylinder, the middle of the connecting seat is provided with a through groove 2, the surface of the connecting seat close to the through groove 2 is provided with a positioning groove 1, and the piston cylinder is provided with a positioning assembly near the connecting seat, and the positioning assembly includes a limit plate clamped in the middle of the piston cylinder, the surface of the limit plate is provided with a plurality of slots 3, and the surface of the limit plate is plugged with a plurality of limit bolts. The surface of the limit plate is provided with a positioning groove three for the limit bolt to be inserted, and the end of the limit bolt is threadedly connected to the limit nut, and the front anchor assembly includes an anchor plate 1 inserted in the support tube, and a plurality of slots 1 are provided on the surface of the anchor plate 1, and a plurality of positioning slots 2 are provided on the surface of the anchor plate 1 for the limit nut to be inserted, and a plurality of clamping grooves 1 are provided on the surface of the anchor plate 1 close to the limit plate, and the clamping grooves 1 are connected with the slots 1 in sequence, and the interior of the clamping grooves 1 is provided with a second clip assembly, and the second clip assembly includes a clip 2 that is clamped in the interior of the clamping groove 1, and the box beam anchor assembly includes an anchor plate 2, a slot 2 is provided on the side wall of the anchor plate 2, and a clamping groove 2 is provided on the side wall of the anchor plate 2 close to the anchor plate 1, and a first clip assembly is provided in the interior of the clamping groove 2, and the first clip assembly includes a clip 1 that is clamped in the interior of the clamping groove 2.

[0008] Furthermore, a lifting ear is fixedly provided on the top of the cylinder body, a plurality of holes and grooves are opened on the side wall of the lifting ear, a supporting foot is fixedly provided on the end of the support tube, the internal size of the support tube is matched with the external size of the anchor plate 2, and the support tube is connected with the through slot 1, which improves the convenience of lifting the cylinder body.

[0009] Furthermore, the piston cylinder and the sealing seat are fixedly connected to form an integrated structure. The sealing seat is annular and matched with the internal size of the slide groove. A sealing ring is clamped on the outer surface of the sealing seat. The first oil nozzle and the second oil nozzle are connected to the slide groove in sequence, thereby improving the stability of the piston cylinder movement.

[0010] Furthermore, the slot one is symmetrically distributed, and the slot one is adapted to the internal dimensions of the slot two and the limit bolt in turn. The slot one corresponds to the position of the slot two and the limit bolt in turn for the prestressed tendon to be plugged in, thereby improving the convenience of the installation and positioning of the prestressed tendon.

[0011] Furthermore, the positioning grooves 2 are symmetrically distributed, and the positioning grooves 2 correspond to the positions of the positioning grooves 3 and 1 respectively. The external dimensions of the limit bolts are matched with the internal dimensions of the positioning grooves 2, 3 and 1 respectively, thereby improving the convenience of installation and positioning of the anchor plate 1 and the limit plate.

[0012] Furthermore, a slot three is provided in the middle of the clip one, and a clamp one is clamped on the side wall of the clip one. The clamp one is made of rubber and is in a circular ring shape. The outer size of the clip one is matched with the inner size of the slot two, thereby improving the stability of the installation of the clip one.

[0013] Furthermore, a slot four is provided in the middle of the clip two for inserting the prestressed tendons, a clamp two is clamped on the outer surface of the clip two, and the outer dimensions of the clip two are matched with the inner dimensions of the slot two in turn. The clip two and the clip one are both made of titanium alloy, which improves the stability of the installation of the clip two.

[0014] Furthermore, a spring is fixedly provided on the surface of the limit plate close to the slot three, and a support ring is fixedly provided on the other end of the spring. The support ring is supported on the end of the clip two, and the support ring is in a circular ring shape and is connected with the spring and the slot three in sequence, thereby improving the convenience of locking the clip two.

[0015] The process of changing the rear anchor type tensioning jack to the front card type includes the following steps:

[0016] S1: Preparation work, three clips 2 are spliced ​​into a group, and then the clamp 2 is set on the outer surface of the clip 2, and the clamp 2 is clamped on the outer surface of the clip 2 in sequence, and then the assembled clip 2 is inserted into the inside of the slot 1 in sequence, and the limit plate is clamped on the inner wall of the connecting seat. The limit bolt passes through the positioning slot 3, positioning slot 1 and positioning slot 2 in sequence, and the limit nut is threadedly connected to the end of the limit bolt, so that the slot 1 corresponds to the slot 3 in sequence, and the support tube is set on the outer surface of the anchor plate 2 through the lifting equipment, so that the prestressed tendon inserted between the anchor plate 2 and the slot 3 is inserted in the middle of the slot 1, slot 4 and slot 3 in sequence, and the limit nut is turned to adjust the distance between the anchor plate 1 and the limit plate, so that the spring is compressed, so that the clip 2 is locked, and the distance between the anchor plate 2 and the anchor plate 1 is shortened. The installation method of the other end of the prestressed tendon is the same as above.

[0017] S2: tensioning operation, the positioning groove three and the support ring are connected with the oil pump through the pipeline in turn, the oil pump is started to transport the hydraulic oil from the first oil nozzle to the inside of the slide groove, and the hydraulic oil inside the slide groove is discharged from the second oil nozzle, so as to maintain the oil pressure balance, and push the sealing seat to move horizontally along the slide groove, thereby driving the limit plate and the anchor plate 1 to move horizontally synchronously, so as to tension the steel bar. When the tensioning is completed, the clamp 1 is clamped at the end of the clamping groove 2 under the action of the friction force of the prestressed tendon, so as to realize the anchoring of the two ends of the prestressed tendon.

[0018] S2: Dismantling operation, the oil pump returns oil to reset the piston cylinder, thereby releasing the tension at both ends of the prestressed tendons. The operator turns the limit nut to release the support limit of the anchor plate 1, thereby separating the anchor plate 1 and the support cylinder. At this time, the operator can remove the Qianjinding assembly to facilitate cutting the two ends of the anchor plate to tension the excess prestressed tendons.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] Firstly, the rear anchor type of the tensioning jack in the present invention is replaced by the front clamp type through the cooperation of the jack assembly, the front clamp anchor assembly, the box beam anchor assembly, the first clip assembly, the positioning assembly and the second clip assembly, the support cylinder is sleeved on the outer surface of the piston cylinder to support the limit cylinder body, and the limit plate, the front clamp anchor assembly and the limit nut are matched, so as to shorten the layout spacing of the anchor plate 2 and the anchor plate 1, thereby reducing the loss of prestressed tendons and thus the production cost;

[0021] Secondly, the rear anchor type of the tensioning jack in the present invention is changed to the front clamp type through the matching of the slot 1, the positioning slot 2, the slot 3, the positioning slot 3, the positioning slot 1 and the limit bolt, thereby improving the efficiency of the installation and positioning of the limit plate, the clip 2 and the prestressed tendon;

[0022] Thirdly, the rear anchor type of the tensioning jack in the present invention is replaced by the front clamp type by providing a spring and a support ring, and the support ring is supported on the end of the second clip, thereby improving the stability of the installation and positioning of the second clip. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the front three-dimensional structure of the present invention;

[0024] Figure 2 It is a side view stereoscopic structural schematic diagram of the present invention;

[0025] Figure 3 is a schematic diagram of the first anchor installation structure of the present invention;

[0026] Figure 4 It is a schematic diagram of the cross-sectional installation structure of the Qianjinding component of the present invention;

[0027] Figure 5 It is a schematic diagram of the cross-sectional installation structure of the piston cylinder of the present invention;

[0028] Figure 6 It is a schematic diagram of the front view of the three-dimensional structure of the piston cylinder of the present invention;

[0029] Figure 7 It is a schematic diagram of the installation structure of the front anchoring device of the present invention from a side view;

[0030] Figure 8 It is a schematic diagram of the front stereoscopic structure of the front anchor of the present invention;

[0031] Fig. 9 It is a schematic diagram of the front view of the three-dimensional structure of the limiting component of the present invention.

[0032] The numbers in the figure are: 1. Qianjinding assembly; 101. Cylinder; 102. Support cylinder; 103. Piston cylinder; 104. First oil nozzle; 105. Lifting ear; 106. Second oil nozzle; 107. Through slot 1; 108. Hole slot; 109. Support foot; 110. Sealing seat; 111. Slide slot; 112. Connecting seat; 113. Through slot 2; 114. Sealing ring; 115. Positioning slot 1; 2. Front anchor assembly; 201. Anchor plate 1; 202. Slot 1; 203. Positioning slot 2; 20 4. Slot one; 3. Box girder anchor assembly; 301. Anchor plate two; 302. Slot two; 303. Slot two; 4. First clip assembly; 401. Clip one; 402. Slot three; 403. Clamp one; 5. Positioning assembly; 501. Limit plate; 502. Limit bolt; 503. Slot three; 504. Positioning slot three; 505. Spring; 506. Support ring; 507. Limit nut; 6. Second clip assembly; 601. Clip two; 602. Slot four; 603. Clamp two. DETAILED DESCRIPTION

[0033] In order to further understand the features, technical means, specific objectives and functions of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0034] refer to Figures 1 to 9The tensioning jack shown in the figure has a rear anchor type and a front clamp type, which includes a jack assembly 1, a front clamp anchor assembly 2 and a box beam anchor assembly 3. The jack assembly 1 includes a cylinder body 101. The ends of the cylinder body 101 are fixedly provided with support cylinders 102 by welding to support the cylinder body 101 at both ends of the prefabricated beam to limit the position. The middle of the support cylinder 102 is movably connected with a piston cylinder 103. The end of the piston cylinder 103 is fixedly provided with a sealing seat 110. A through groove 107 is provided in the middle of the cylinder body 101. The support cylinder 102 and the through groove 107 are connected for the insertion of prestressed tendons. A slide groove 111 is provided inside the cylinder body 101 for the sealing seat 110 to slide. The piston cylinder 103 and the sealing seat 110 are fixedly connected to form an integrated structure. The sealing seat 110 is annular and is connected to the inside of the slide groove 111. The sizes are adapted to improve the stability of the piston cylinder 103 movement. The outer surface of the sealing seat 110 is clamped with a sealing ring 114 to improve the sealing of the sealing seat 110 movement. The first oil nozzle 104 is inserted on the side wall of the cylinder body 101, and the second oil nozzle 106 is inserted on the side wall of the cylinder body 101 close to the first oil nozzle 104. The first oil nozzle 104 and the second oil nozzle 106 are connected to the slide groove 111 in turn, and the first oil nozzle 104 and the second oil nozzle 106 are connected to the oil pump through a pipeline in turn. When the oil pump is started, the hydraulic oil inside the slide groove 111 can be adjusted to push. A connecting seat 112 is fixed on the inner wall of the piston cylinder 103 for supporting and limiting. A through groove 113 is opened in the middle of the connecting seat 112 for the prestressed tendon to be inserted. The connecting seat 112 is close to the through groove The surface of the second 113 is provided with a positioning groove 115 for installation and positioning, and a positioning component 5 is arranged inside the piston cylinder 103 near the connecting seat 112. The positioning component 5 includes a limit plate 501 which is clamped in the middle of the piston cylinder 103, and a plurality of slots 503 are provided on the surface of the limit plate 501. A plurality of limit bolts 502 are inserted on the surface of the limit plate 501 for connection and positioning, and a positioning groove 3 504 is provided on the surface of the limit bolt 502 for insertion, and the end of the limit bolt 502 is threadedly connected to the limit nut 507. The front anchor assembly 2 includes an anchor plate 201 which is inserted into the inside of the support cylinder 102, and a plurality of slots 202 are provided on the surface of the anchor plate 201. A plurality of positioning grooves 204 are provided on the surface of the anchor plate 201. 203 is provided for the insertion of the limiting nut 507, and a plurality of card slots 204 are provided on the surface of the anchor plate 201 near the limiting plate 501, and the card slots 204 are connected with the slots 202 in sequence, and the interior of the card slots 204 is provided with a second clip assembly 6, and the second clip assembly 6 includes a clip 2 601 clamped in the interior of the card slot 204, and a card slot 4 602 is provided in the middle of the clip 2 601 for the insertion of the prestressed tendon, and the outer surface of the clip 2 601 is clamped with a clamp 2 603, and the outer dimensions of the clip 2 601 are adapted to the inner dimensions of the card slot 2 303 in sequence, thereby improving the installation stability of the clip 2 601, and the clip 2 601 clamps the prestressed tendon by friction, so that the two ends of the prestressed tendon are clamped stably in the interior of the slot 202 in sequence,The second clip 601 is pre-clamped in the interior of the card slot 204 to improve the assembly efficiency during tensioning. The box girder anchor assembly 3 includes a second anchor plate 301, a second slot 302 is provided on the side wall of the second anchor plate 301, a second card slot 303 is provided on the side wall of the second anchor plate 301 close to the first anchor plate 201, and a first clip assembly 4 is provided inside the second card slot 303. The first clip assembly 4 includes a clip 401 clamped in the interior of the second card slot 303, and a third card slot 4 is provided in the middle of the clip 401. 02, the side walls of the clip 1 401 are clamped with a clamp 1 403, the clamp 1 403 is made of rubber and is in a circular ring shape, the outer size of the clip 1 401 is adapted to the inner size of the slot 2 303, the clip 2 601 and the clip 1 401 are both made of titanium alloy, which improves the stability of the installation of the clip 1 401, and the support tube 102 is set on the outer surface of the anchor plate 2 301 through the lifting equipment, so that the prestressed tendons inserted between the anchor plate 2 301 and the slot 3 402 are inserted in the slot 1 202, the slot 4 601 and the slot 5 602 in sequence. 02, the middle of the slot three 503, turn the limit nut 507 to adjust the distance between the anchor plate 1 201 and the limit plate 501, so that the spring 505 is compressed, so that the clamp 2 601 is locked, shortening the distance between the anchor plate 2 301 and the anchor plate 1 201, the installation method of the other end of the prestressed tendon is the same as above, start the oil pump to make the hydraulic oil, from the first oil nozzle 104 to the inside of the slide 111, the hydraulic oil in the slide 111 is discharged from the second oil nozzle 106, so as to maintain the oil pressure balance, from pushing the sealing seat 110 along the slide The groove 111 moves horizontally, thereby driving the limit plate 501 and the anchor plate 1 201 to move horizontally synchronously, so that the steel bar is tensioned. When the tensioning is completed, the clip 1 401 is clamped at the end of the clamping groove 2 303 under the action of the friction force of the prestressed tendon, thereby realizing the anchoring of both ends of the prestressed tendon. The support cylinder 102 and the connecting seat 112 support the limit, thereby shortening the layout spacing of the anchor plate 1 201 and the anchor plate 2 301, thereby reducing the length of loss when the prestressed tendon is tensioned, thereby reducing the loss cost and improving the production efficiency of prefabricated beams.

[0035] Furthermore, a first oil nozzle 104 is fixedly provided at the top of the cylinder body 101, a plurality of holes 108 are opened on the side wall of the lifting ear 105, and a supporting foot 109 is fixedly provided at the end of the support tube 102, thereby increasing the contact area and improving the stability of the support of the support tube 102. A plurality of slots are opened on the side wall of the support tube 102 near the supporting foot 109 for equipment operation, which facilitates the operator to turn the limit nut 507. The internal dimensions of the support tube 102 are compatible with the external dimensions of the anchor plate 301, thereby improving the convenience of lifting the cylinder body 101.

[0036] Furthermore, slot one 202 is symmetrically distributed, and slot one 202 is adapted to the internal dimensions of slot two 302 and the limit bolt 502 in turn. Slot one 202 corresponds to the positions of slot two 302 and the limit bolt 502 in turn for the prestressed tendons to be plugged in, thereby improving the convenience of the installation and positioning of the prestressed tendons.

[0037] Furthermore, the positioning grooves 203 are symmetrically distributed, and the positioning grooves 203 correspond to the positions of the positioning grooves 3 504 and the positioning grooves 1 115 in sequence. The external dimensions of the limit bolt 502 are adapted to the internal dimensions of the positioning grooves 203, 504 and the positioning grooves 1 115 in sequence, thereby improving the convenience of installation and positioning of the anchor plate 201 and the limit plate 501.

[0038] Furthermore, a spring 505 is fixedly provided on the surface of the limit plate 501 close to the slot three 503, and a support ring 506 is fixedly provided at the other end of the spring 505. The support ring 506 is supported on the end of the clip two 601. The support ring 506 is in a circular ring shape and is connected with the spring 505 and the slot three 503 in sequence, thereby improving the convenience of locking the clip two 601.

[0039] The process of changing the rear anchor type tensioning jack to the front card type includes the following steps:

[0040] S1: Preparation work, three clips 601 are spliced ​​into a group, and then the clamp 603 is set on the outer surface of the clip 601, and the clamp 603 is clamped on the outer surface of the clip 601 in sequence, and then the assembled clips 601 are inserted into the inside of the slot 1 202 in sequence, and the limit plate 501 is clamped on the inner side wall of the connecting seat 112. The limit bolt 502 passes through the positioning groove 3 504, the positioning groove 1 115 and the positioning groove 203 in sequence, and the limit nut 507 is threadedly connected to the end of the limit bolt 502, so that the slot 1 202 is connected according to Corresponding to slot three 503, the support tube 102 is sleeved on the outer surface of the anchor plate two 301 through the lifting equipment, so that the prestressed tendon inserted between the anchor plate two 301 and the slot three 402 is inserted in the middle of the slot one 202, the slot four 602 and the slot three 503 in sequence, and the limit nut 507 is rotated to adjust the distance between the anchor plate one 201 and the limit plate 501, so that the spring 505 is compressed, so that the clip two 601 is locked, and the distance between the anchor plate two 301 and the anchor plate one 201 is shortened. The installation method of the other end of the prestressed tendon is the same as above.

[0041] S2: tensioning operation, the positioning groove three 504 and the support ring 506 are connected to the oil pump through the pipeline in sequence, and the oil pump is started to transport the hydraulic oil from the first oil nozzle 104 to the inside of the slide groove 111, and the hydraulic oil inside the slide groove 111 is discharged from the second oil nozzle 106, so as to maintain the oil pressure balance, and push the sealing seat 110 to move horizontally along the slide groove 111, thereby driving the limit plate 501 and the anchor plate 201 to move horizontally synchronously, so as to tension the steel bar. When the tensioning is completed, the clip 1 401 is clamped at the end of the clamping groove 2 303 under the action of the friction force of the prestressed tendon, thereby realizing the anchoring of the two ends of the prestressed tendon.

[0042] S2: Dismantling operation, the oil pump returns oil to reset the piston cylinder 103, thereby releasing the tension at both ends of the prestressed tendons, and the operator turns the limit nut 507 to release the support limit on the anchor plate 201, thereby separating the anchor plate 201 and the support cylinder 102. At this time, the operator can remove the Qianjinding assembly 1 to facilitate the cutting of the end of the anchor plate 2 301 to tension the excess prestressed tendons.

[0043] The above embodiments only express one or several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the attached claims.

Claims

1. A tensioning jack that changes from a rear anchor type to a front clamp type, comprising a jack assembly (1), a front clamp anchor assembly (2) and a box beam anchor assembly (3), characterized in that: The Qianjinding assembly (1) comprises a cylinder body (101), a support cylinder (102) is fixedly provided at the end of the cylinder body (101), a piston cylinder (103) is movably connected in the middle of the support cylinder (102), a sealing seat (110) is fixedly provided at the end of the piston cylinder (103), a through groove (107) is provided in the middle of the cylinder body (101), a sliding groove (111) is provided inside the cylinder body (101) for the sealing seat (110) to slide, and a plug-in element (112) is inserted on the side wall of the cylinder body (101). A first oil nozzle (104) is connected, a second oil nozzle (106) is inserted on the side wall of the cylinder body (101) close to the first oil nozzle (104), a connecting seat (112) is fixedly provided on the inner side wall of the piston cylinder (103), a second through groove (113) is provided in the middle of the connecting seat (112), a first positioning groove (115) is provided on the surface of the connecting seat (112) close to the second through groove (113), and a positioning assembly (5) is provided inside the piston cylinder (103) close to the connecting seat (112); The positioning assembly (5) comprises a limiting plate (501) clamped in the middle of the piston cylinder (103), a plurality of slots (503) are provided on the surface of the limiting plate (501), a plurality of limiting bolts (502) are plugged into the surface of the limiting plate (501), a positioning groove (504) is provided on the surface of the limiting plate (501) for the limiting bolts (502) to be plugged in, and the end of the limiting bolt (502) is threadedly connected to a limiting nut (507); The front anchor assembly (2) includes an anchor plate (201) inserted into the support tube (102), a plurality of slots (202) are provided on the surface of the anchor plate (201), a plurality of positioning slots (203) are provided on the surface of the anchor plate (201) for the limit nut (507) to be inserted, a plurality of slots (204) are provided on the surface of the anchor plate (201) close to the limit plate (501), the slots (204) are connected with the slots (202) in sequence, a second clip assembly (6) is provided inside the slots (204), and the second clip assembly (6) includes a clip (601) which is clamped inside the slots (204); The box girder anchor assembly (3) includes an anchor plate 2 (301), a slot 2 (302) is provided on the side wall of the anchor plate 2 (301), a clamping groove 2 (303) is provided on the side wall of the anchor plate 2 (301) close to the anchor plate 1 (201), a first clip assembly (4) is arranged inside the clamping groove 2 (303), and the first clip assembly (4) includes a clip 1 (401) clamped inside the clamping groove 2 (303).

2. The tensioning jack of rear anchor type changing to front clamp type according to claim 1 is characterized in that: A lifting ear (105) is fixedly provided at the top of the cylinder body (101), and a plurality of holes (108) are opened on the side wall of the lifting ear (105). A supporting foot (109) is fixedly provided at the end of the support tube (102). The internal dimensions of the support tube (102) are compatible with the external dimensions of the anchor plate 2 (301), and the support tube (102) is connected to the through groove 1 (107).

3. The tensioning jack of rear anchor type changing to front clamp type according to claim 1 is characterized in that: The piston cylinder (103) and the sealing seat (110) are fixedly connected to form an integrated structure; the sealing seat (110) is annular and matches the inner dimensions of the slide groove (111); a sealing ring (114) is clamped on the outer surface of the sealing seat (110); and the first oil nozzle (104) and the second oil nozzle (106) are connected to the slide groove (111) in sequence.

4. The tensioning jack of rear anchor type changing to front clamp type according to claim 1, characterized in that: The slots 1 (202) are symmetrically distributed, and the slots 1 (202) are adapted to the internal dimensions of the slots 2 (302) and the limit bolt (502) in turn. The slots 1 (202) are positioned correspondingly to the slots 2 (302) and the limit bolt (502) for the prestressed tendons to be plugged in.

5. The tensioning jack of rear anchor type changing to front clamp type according to claim 1 is characterized in that: The second positioning grooves (203) are symmetrically distributed, and the second positioning grooves (203) correspond to the positions of the third positioning groove (504) and the first positioning groove (115) in sequence. The external dimensions of the limit bolt (502) are adapted to the internal dimensions of the second positioning groove (203), the third positioning groove (504) and the first positioning groove (115) in sequence.

6. The tensioning jack of rear anchor type changing to front clamp type according to claim 1, characterized in that: A clamping groove three (402) is provided in the middle of the clamping piece one (401), and a clamping hoop one (403) is clamped on the side wall of the clamping piece one (401). The clamping hoop one (403) is made of rubber material and is in a circular ring shape. The external dimensions of the clamping piece one (401) are compatible with the internal dimensions of the clamping groove two (303).

7. The tensioning jack of rear anchor type changing to front clamp type according to claim 1 is characterized in that: A fourth clamping groove (602) is provided in the middle of the second clip (601) for inserting the prestressed tendon, and a second clamp (603) is clamped on the outer surface of the second clip (601). The outer dimensions of the second clip (601) are matched with the inner dimensions of the second clamping groove (303) in turn. The second clip (601) and the first clip (401) are both made of titanium alloy.

8. The tensioning jack of rear anchor type changing to front clamp type according to claim 1 is characterized in that: A spring (505) is fixedly provided on the surface of the limiting plate (501) close to the third slot (503), and a support ring (506) is fixedly provided on the other end of the spring (505). The support ring (506) is supported on the end of the second clamp (601), and the support ring (506) is in a circular ring shape and is connected with the spring (505) and the third slot (503) in sequence.

9. A tensioning jack of rear anchor type is changed to front clamp type, adopting the tensioning jack of rear anchor type is changed to front clamp type as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: S1: Preparation work, three clips 2 (601) are spliced ​​into a group, and then the clamp 2 (603) is sleeved on the outer surface of the clip 2 (601), and the clamp 2 (603) is clamped on the outer surface of the clip 2 (601) in sequence, and then the assembled clip 2 (601) is inserted into the inside of the slot 1 (202) in sequence, and the limit plate (501) is clamped on the inner side wall of the connecting seat (112), and the limit bolt (502) passes through the positioning groove 3 (504), the positioning groove 1 (115) and the positioning groove 2 (203) in sequence, and the limit nut (507) is threadedly connected to the end of the limit bolt (502), so that the slot 1 (202) Corresponding to slot three (503) in sequence, the support tube (102) is sleeved on the outer surface of the anchor plate two (301) through the lifting equipment, so that the prestressed tendon inserted between the anchor plate two (301) and the slot three (402) is inserted in the middle of slot one (202), slot four (602), and slot three (503) in sequence, and the limiting nut (507) is rotated to adjust the distance between the anchor plate one (201) and the limiting plate (501), so that the spring (505) is compressed, so that the clip two (601) is locked, shortening the distance between the anchor plate two (301) and the anchor plate one (201), and the installation method of the other end of the prestressed tendon is the same as above. S2: tensioning operation, the positioning groove three (504) and the support ring (506) are connected to the oil pump through the pipeline in sequence, the oil pump is started to transport the hydraulic oil from the first oil nozzle (104) to the inside of the slide groove (111), and the hydraulic oil inside the slide groove (111) is discharged from the second oil nozzle (106), so as to maintain the oil pressure balance, and push the sealing seat (110) to move horizontally along the slide groove (111), thereby driving the limit plate (501) and the anchor plate one (201) to move horizontally synchronously, so that the steel bar is tensioned. When the tensioning is completed, the clamp one (401) is clamped at the end of the clamping groove two (303) under the action of the friction force of the prestressed tendon, so as to realize the anchoring of the two ends of the prestressed tendon. S2: Dismantling operation, the oil pump returns oil to reset the piston cylinder (103), thereby releasing the tension at both ends of the prestressed tendons. The operator turns the limit nut (507) to release the support limit on the anchor plate 1 (201), thereby separating the anchor plate 1 (201) and the support cylinder (102). At this time, the operator can remove the Qianjinding assembly (1) to facilitate cutting the end of the anchor plate 2 (301) to tension the excess prestressed tendons.

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