Prestress tensioning jack and using method thereof

Abstract

The invention relates to the technical field of prestress tensioning equipment, in particular to a prestress tensioning jack and a using method thereof.The prestress tensioning jack comprises an outer cylinder, a middle cylinder arranged in the outer cylinder, a first piston arranged at the bottom of the middle cylinder, a cylinder outlet oil port and a cylinder return oil port which are formed in the positions, on the two sides of the first piston, of the outer cylinder, and an inner cylinder arranged in the middle cylinder; the inner cylinder is sleeved with the first piston in a sliding and sealing mode, a bottom shell is arranged at the bottom of the inner cylinder, and a pressurization mechanism is arranged on the bottom shell; the pressurizing mechanism comprises a bottom cylinder arranged below the outer cylinder, a second piston sleeved in the bottom cylinder in a sliding and sealing mode and a third piston sleeved in the outer cylinder in a sliding and sealing mode, the second piston and the third piston are of an integrated structure, the second piston and the third piston are both movably sleeved on the inner cylinder, and the inner cylinder, the second piston and the third piston form a conveying channel. The invention provides a prestress tensioning jack and a using method thereof. The prestress tensioning jack widens the stress application range and enhances the stability of an anchoring system in the tensioning process, and the prestress tensioning jack is used for overcoming the defects in the prior art.

Description

Technical Field

[0001] The invention relates to the technical field of prestressed tensioning equipment, and in particular to a prestressed tensioning jack and a use method thereof. Background Art

[0002] Prestressed jack is a hydraulic jack device specially designed for tensioning prestressed tendons such as steel strands and steel bars. The working principle of this equipment is to generate prestressed stress in the concrete structure before it bears the load by tensioning the prestressed tendons, thereby significantly improving the crack resistance and bearing capacity of the structure. Therefore, prestressed jacks have been widely used in many fields such as bridge construction, building construction, and tunnel engineering. Prestressed jacks are a type of through-hole hydraulic jacks. Their unique structural design is that a through-hole is set on the central axis. By passing the prestressed tendons through the through-hole and then firmly anchoring the jack on the prestressed tendons with anchors, the required stress can be effectively applied to the prestressed tendons. In the actual use of prestressed jacks, the prestressed jacks need to work in conjunction with the high-pressure oil pump, which is responsible for delivering high-pressure oil to the jacks, and the hydraulic system inside the jacks converts these high-pressure oils into powerful tensioning forces. By utilizing this tensioning force, the prestressing jack can apply the necessary stress to the prestressed tendons passing through it, thereby achieving tensioning of the prestressed tendons. After the prestressed tendons are tensioned to the required degree, anchors are needed to anchor these prestressed tendons to ensure that the prestress can be stably maintained on the prestressed tendons. Through such an operation process, the prestressing jack applies prestress to the prestressed tendons.

[0003] In the field of prestressed construction, handheld and pedestal jacks are two common types. Pedestal prestressed jacks are suitable for occasions that require stable support and large tension. For this reason, pedestal prestressed jacks play an important role in the construction of large structures such as large bridges and high-rise buildings. However, when facing narrow spaces or complex environments with unstable support conditions, pedestal prestressed jacks are difficult to use on prestressed tendons due to their large size. Relatively speaking, handheld prestressed jacks are widely used in various prestressed construction projects such as highway bridges, railway bridges, hydropower dams, high-rise buildings, etc. due to their compact structure, easy to carry, simple assembly, and suitable for use in a variety of complex environments.

[0004] Handheld jacks are the preferred tool for construction workers due to their excellent portability and adaptability. However, due to their small size, the stress that handheld prestressed jacks can provide is far less than that of pedestal jacks. In specific environments and working conditions where the tension design requirements are high, the stress applied by handheld jacks is difficult to meet the design requirements, which will cause the stress amplitude of the constructed structure to increase when subjected to repeated loads, resulting in premature cracking of the structure and a large deflection, which will reduce the service life of the structure and even cause the clip to loosen or even fall out of the anchor ring, thus affecting the safety of the entire building. Therefore, there is room for improvement in handheld jacks for prestressed construction. By optimizing the structure of the handheld jack, increasing the range of applied stress of the handheld jack, and enhancing the stability of the anchoring system during the tensioning process, such improvements are not only of great practical significance for prestressed construction, but also of considerable value in improving project quality and ensuring building safety. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a prestressed tensioning jack and a method of using the same, which can improve the range of applied stress and enhance the stability of the anchoring system during the tensioning process, so as to overcome the defects in the prior art.

[0006] The technical solution adopted by the present invention is: a prestressed tensioning jack, comprising an outer cylinder, a middle cylinder arranged in the outer cylinder, a first piston arranged at the bottom of the middle cylinder, and the outer cylinders on both sides of the first piston are respectively provided with cylinder oil outlets and cylinder oil return ports, the inner cylinder arranged in the middle cylinder, the first piston slidingly sealingly sleeved on the inner cylinder, a bottom shell is arranged at the bottom of the inner cylinder, and a booster mechanism is arranged on the bottom shell; the booster mechanism comprises a bottom cylinder arranged below the outer cylinder, a second piston slidingly sealingly sleeved in the bottom cylinder, and a third piston slidingly sealingly sleeved in the outer cylinder, the second piston and the third piston are an integral structure, the second piston and the third piston are movably sleeved on the inner cylinder, the inner cylinder and the second piston and the third piston form a conveying channel, the cylinder oil outlet is connected to the inner cavity of the outer cylinder through the inner cavity of the bottom cylinder and the conveying channel; a pressure relief hole is opened on the outer wall of the bottom cylinder, and the pressure relief hole is located above the second piston.

[0007] Preferably, a press body is provided on the side of the inner cylinder away from the bottom shell, the press body and the inner cylinder are an integral structure, and a press mechanism is provided on the press body; the press mechanism includes a spring provided in the press body, an anchor ring provided at one end of the press body away from the inner cylinder, and a plurality of clips movably mounted in the anchor ring, the anchor ring is mounted on the press body, the inner cavity of the anchor ring adopts a conical groove structure, the outer shapes of the plurality of clips are consistent with the inner cavity shape of the anchor ring, and the plurality of clips are fixed in the anchor ring by spring extrusion.

[0008] Preferably, a top anchor tube is provided on the side of the clip away from the spring, the top anchor tube is movably sleeved in the anchor ring, one side of the top anchor tube is in contact with the clip, and a top head is provided on the other side of the top anchor tube, and the top anchor tube is connected to the middle cylinder through the top head; a compression sleeve is sleeved inside the spring, a compression ring is provided at one end of the compression sleeve, the compression ring and the compression sleeve are an integral structure, the compression ring is located between the spring and the clip, and both sides of the spring are in contact with the inner cylinder and the compression ring respectively.

[0009] Preferably, the inner diameter of the outer cylinder is and the inner diameter of the sump The relationship between them should satisfy Formula 1, which is ,in is the coefficient of applied force, .

[0010] Preferably, the top of the bottom cylinder is installed on the bottom of the outer cylinder, the inner thread of the pressure relief hole is sleeved with a cover, and a fixing groove and a ventilation groove are respectively provided on the cover. The pressure relief hole is connected to the bottom cylinder through the ventilation groove. The fixing groove adopts a polygonal groove structure, and the fixing groove is opened on the side of the cover away from the inner cylinder.

[0011] Preferably, a transverse hole and a through groove are respectively provided at one end of the third piston away from the second piston, the transverse hole is transversely provided on the end face of the third piston, the through groove adopts a circular groove structure, the through groove extends along the end face of the third piston toward the middle part of the third piston, the through groove is connected with the conveying channel through the transverse hole, a sealing gasket is provided between the second piston and the bottom shell, the sealing gasket is installed on the bottom shell, the sealing gasket is fixedly mounted between the bottom cylinder and the inner cylinder, a sleeve groove is provided on the side of the sealing gasket close to the second piston, and the sleeve groove is provided in the middle part of the end face of the sealing gasket.

[0012] Preferably, a transverse groove is provided on the outer cylinder above the return oil port, the transverse groove is provided on the inner wall of the outer cylinder, a sealing ring made of elastic material is interference fit in the transverse groove, and the sealing ring is interference fit on the middle cylinder.

[0013] Preferably, a handle is provided on the outer cylinder, one side of the handle is mounted on the outer wall of the outer cylinder, the first piston sliding seal is sleeved in the outer cylinder, the first piston and the middle cylinder are an integral structure, and the cylinder oil outlet is located between the bottom cylinder and the first piston.

[0014] The method for using the prestressed tensioning jack includes the following steps: S1, taking out the oil pump and the prestressed tensioning jack, placing the oil pump on one side of the prestressed tensioning jack, then connecting the oil outlet of the cylinder with the oil outlet of the oil pump by using a high-pressure hose, and connecting the oil return port of the cylinder with the oil return port of the oil pump by using another high-pressure hose to complete the assembly of the oil pump and the prestressed tensioning jack; S2, controlling the operating valve of the oil pump to control the middle cylinder to move toward the bottom cylinder, thereby driving the top anchor pipe toward Move close to the clip to drive the clip to move away from the anchor ring, thereby completing the preparation operation; S3, move the oil pump and the prestressed tensioning jack into the operating area, insert the prestressed tendons to be tensioned into the inner cylinder, and make the top head contact the anchor cable anchor installed on the prestressed tendons, and control the operating valve of the oil pump to make the oil flow toward the oil outlet of the cylinder, thereby pushing the first piston, the middle cylinder, the top anchor pipe and the top head to move along the inner wall of the outer cylinder in the direction away from the bottom cylinder. At the same time, Under the squeezing action of the spring, the pressure ring and several clips are pushed toward the anchor ring to anchor the prestressed tendon in the anchor ring, thereby applying a tensioning force to the prestressed tendon; S4. As the oil pressure delivered by the oil pump continues to increase, the oil entering the outer cylinder pushes the second piston and the third piston to move toward the first piston, thereby exerting a squeezing force on the first piston and the middle cylinder to increase the tensioning force of the prestressed tendon anchor, thereby improving the tensioning effect of the prestressed tendon; S5. After the prestressed tendon is tensioned, the operating valve of the oil pump is operated in the reverse direction , so that the oil is transported toward the return cylinder oil port, pushing the first piston, the middle cylinder, the top anchor pipe and the top head to reset, thereby driving the top anchor pipe to move toward the direction close to the clamp, and squeezing the clamp to move in the direction away from the anchor ring to release the anchoring of the prestressed tendon. At the same time, the second piston and the third piston are reset by the first piston; S6, close the operating valve of the oil pump, remove the prestressed tensioning jack from the prestressed tendon, so that the prestressed tensioning jack and the oil pump can be used again to tension the prestressed tendon.

[0015] Preferably, after the oil pump and the prestressed tensioning jack are assembled, the hydraulic system between the oil pump and the prestressed tensioning jack equipment should be checked for leakage. The oil pump operating valve is controlled to deliver oil toward the cylinder oil outlet or cylinder oil return port, and the oil pump, prestressed tensioning jack and high-pressure hose are observed to see if there is leakage. If leakage occurs, the oil pump operating valve is closed first, and then the leakage is maintained to ensure the safety of using the oil pump and the prestressed tensioning jack.

[0016] The beneficial effects of the present invention are as follows: first, the present invention converts the pressure of the oil into a tensioning force by means of a first piston arranged in the outer cylinder, and creates a delivery channel between the inner cylinder and the second piston, so that the second piston can be pushed toward the first piston by using high-pressure oil to increase the applied stress, thereby improving the tensioning effect. The third piston sliding seal is sleeved in the outer cylinder to prevent the oil from flowing between the outer cylinder and the third piston, restricting the oil from being delivered through the delivery channel, and the pressure relief hole opened on the outer wall of the bottom cylinder makes the bottom cylinder above the second piston connected to the outside world, so as to prevent the air pressure in the outer cylinder from hindering the second piston from converting the pressure into a tensioning force, thereby improving the stability of the tensioning effect.

[0017] Secondly, the spring provided in the present invention can drive the clip to move toward the direction close to the anchor ring, so as to anchor the prestressed tendons inserted into the inner cylinder to the anchor ring, so as to assemble the present invention to the prestressed tendons. The top anchor pipe provided is connected to the middle cylinder, so that the middle cylinder can drive the top anchor pipe to move, so as to use the top anchor pipe to drive the clip to move in the direction away from the anchor ring, thereby releasing the anchoring between the prestressed tendons and the anchor ring, so as to facilitate the removal of the present invention from the prestressed tendons and reduce the difficulty of assembling the present invention with the prestressed tendons. In addition, the present invention provides a compression ring and a compression sleeve, so that the elastic force of the spring is uniformly applied to a plurality of clips, thereby preventing the clips from being offset during the tensioning process.

[0018] Thirdly, the present invention prevents sand, dust and other suspended impurities visible to the naked eye from entering the pressure relief hole through the cover and the ventilation grooves on the cover, thereby preventing the suspended impurities from wearing the second piston and the third piston. The polygonal groove-shaped fixing groove on the side of the cover away from the inner cylinder facilitates the use of a polygonal screwdriver to drive the cover to twist, thereby facilitating the loading and unloading of the cover. The present invention provides transverse holes and through grooves on the third piston to facilitate the delivery of oil to the delivery channel through the through grooves and transverse holes, so as to control the boost mechanism to perform the boost process. The inner cylinder and the bottom cylinder are sealed by the sealing gasket, thereby preventing the oil from leaking from the chamber between the bottom cylinder and the inner cylinder.

[0019] In addition, the present invention has a transverse groove on the inner wall of the outer cylinder to limit the seal ring, and the seal ring is fitted on the middle cylinder through interference fit to seal the outer cylinder and the middle cylinder to prevent oil from leaking from the chambers of the outer cylinder and the middle cylinder. The present invention also has a handle to facilitate carrying the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a three-dimensional schematic diagram of the present invention.

[0021] Figure 2 It is a cross-sectional schematic diagram of the present invention.

[0022] Figure 3 for Figure 2 A magnified schematic diagram of center A.

[0023] Figure 4 for Figure 2 A magnified schematic diagram of point B in the middle.

[0024] Figure 5 It is an exploded view of the assembly of the spring, the compression sleeve, the clip and the anchor ring in the present invention.

[0025] Figure 6 It is a schematic diagram of the structure of the sealing cover in the present invention.

[0026] Figure 7 It is a schematic diagram of the assembly of the second piston and the third piston in the present invention. DETAILED DESCRIPTION

[0027] like Figures 1 to 7 As shown, a prestressed tensioning jack comprises an outer cylinder 1, a middle cylinder 2 arranged in the outer cylinder 1, a first piston 3 arranged at the bottom of the middle cylinder 2, and the outer cylinder 1 on both sides of the first piston 3 are respectively provided with an out-of-cylinder oil port 4 and a return-to-cylinder oil port 5, the first piston 3 is slidingly and sealingly sleeved in the outer cylinder 1, the inner cylinder 6 is arranged in the middle cylinder 2, the first piston 3 is slidingly and sealingly sleeved on the inner cylinder 6, a bottom shell 7 is arranged at the bottom of the inner cylinder 6, and a booster mechanism is arranged on the bottom shell 7; the booster mechanism comprises a bottom cylinder 8 arranged below the outer cylinder 1, a second piston 9 slidingly and sealingly sleeved in the bottom cylinder 8, and a third piston 10 slidingly and sealingly sleeved in the outer cylinder 1, the second piston 9 and the third piston 10 are an integral structure, the second piston 9 and the third piston 10 are both movably sleeved on the inner cylinder 6, the inner cylinder 6 and the second piston 9 and the third piston 10 form a delivery channel 11, the out-of-cylinder oil port 4 is connected to the outer cylinder 1 through the inner cavity of the bottom cylinder 8 and the delivery channel 11 The inner cavity is connected; it is connected to the cylinder oil port 4 through an oil pump, so that the oil is transported to the outer cylinder 1, the delivery channel 11 and the bottom cylinder 8 below the first piston 3 through the oil pump. As the oil pressure continues to increase, the pressure on the outer cylinder 1 and the bottom cylinder 8 is also continuously increased, thereby pushing the first piston 3 and the middle cylinder 2 to move along the inner wall of the outer cylinder 1 for tensioning operation; if pressure increase is required, the oil pressure is continuously increased so that the oil entering the outer cylinder 1 pushes the second piston 9 and the third piston 10 to move, and the oil between the third piston 10 and the first piston 3 is used to transmit force to squeeze the first piston 3 and the middle cylinder 2, thereby increasing the tensioning force, thereby improving the tensioning effect of the present invention; a pressure relief hole 12 is opened on the outer wall of the bottom cylinder 8, and the pressure relief hole 12 is located above the second piston 9, so that the bottom cylinder 8 above the second piston 9 is connected to the outside world to prevent the air pressure in the outer cylinder 1 from affecting the tensioning operation.

[0028] In this embodiment, a press body 13 is provided on the side of the inner cylinder 6 away from the bottom shell 7. The press body 13 and the inner cylinder 6 are an integral structure, and a press mechanism is provided on the press body 13; the press mechanism includes a spring 14 provided in the press body 13, an anchor ring 15 provided at one end of the press body 13 away from the inner cylinder 6, and a plurality of clips 16 movably mounted in the anchor ring 15, the anchor ring 15 is installed on the press body 13, the inner cavity of the anchor ring 15 adopts a conical groove structure, the external shapes of the plurality of clips 16 are consistent with the inner cavity shape of the anchor ring 15, and the plurality of clips 16 are all squeezed and fixed in the anchor ring 15 by the spring 14, and the prestressed tendons inserted into the inner cylinder 6 are anchored to the anchor ring 15 by the clips 16, so that the prestressed tendons are clamped and fixed to the present invention.

[0029] Specifically, a top anchor tube 17 is provided on the side of the clip 16 away from the spring 14, and the top anchor tube 17 is movably mounted in the anchor ring 15. One side of the top anchor tube 17 is in contact with the clip 16, and a top head 18 is provided on the other side of the top anchor tube 17. The top anchor tube 17 is connected to the middle cylinder 2 through the top head 18. The movement of the middle cylinder 2 can drive the top anchor tube 17 and the top head 18 to move. Under the action of the spring 14 squeezing the clip 16, the clip 16 can be controlled to move in or out of the anchor ring 15, so that when oil is applied to the cylinder oil port 4, the middle cylinder 2 drives the top anchor tube 17 to move in a direction away from the clip 16. Under the squeezing action of the spring 14, the clip 16 moves into the anchor ring 15, so that the prestressed tendon passes through the clip 16 is anchored and clamped on the anchor ring 15; and when oil is applied to the return cylinder oil port 5, the middle cylinder 2 drives the top anchor tube 17 to move in the direction close to the clip 16, so as to use the top anchor tube 17 to squeeze the clip 16, thereby releasing the anchoring between the prestressed tendon and the anchor ring 15, so as to facilitate the removal of the present invention from the prestressed tendon; the spring 14 is provided with a compression sleeve 19, and a compression ring 20 is provided at one end of the compression sleeve 19. The compression ring 20 and the compression sleeve 19 are an integral structure, and the compression ring 20 is located between the spring 14 and the clip 16. The two sides of the spring 14 are respectively in contact with the inner cylinder 6 and the compression ring 20. The compression ring 20 is used to make the elastic force of the spring 14 uniform on a plurality of clips 16, thereby preventing the clips 16 from deviating during the tensioning process.

[0030] In this embodiment, the inner diameter of the outer cylinder 1 is and the inner diameter of the bottom cylinder 8 The relationship between them should satisfy Formula 1, which is ,in is the coefficient of applied force. The relationship between applied force and pressure is ,in To apply force, is the area of ​​the effective cross section, is the applied oil pressure; therefore, the force applied by the first piston 3 is ; The force exerted by the second piston 9 ;in is the outer wall diameter of the inner cylinder 6, is the inner diameter of the second piston 9, and the coefficient , , due to the outer diameter of the inner cylinder 6 The inner diameter of the second piston 9 are approximately equal, so we can infer In order to prevent the second piston 9 from applying too little or too much force, the coefficient needs to be selected. Need to meet .

[0031] Please refer to Figure 3 and 5 The top of the bottom cylinder 8 is installed on the bottom of the outer cylinder 1, and the pressure relief hole 12 is internally threaded with a cover 21. The cover 21 is respectively provided with a fixing groove 22 and a ventilation groove 23. The pressure relief hole 12 is connected to the bottom cylinder 8 through the ventilation groove 23. The width of the ventilation groove 23 is not greater than 0.1 mm. Since the diameter of suspended impurities visible to the naked eye, such as sand and dust, is generally above 0.1 mm, the suspended impurities visible to the naked eye are prevented from entering the pressure relief hole 12. The fixing groove 22 adopts a polygonal groove structure. The fixing groove 22 is arranged on the side of the cover 21 away from the inner cylinder 6. The polygonal screwdriver is inserted into the fixing groove 22 and twisted to facilitate the loading and unloading of the cover 21.

[0032] In this embodiment, a transverse hole 24 and a through groove 25 are respectively provided at one end of the third piston 10 away from the second piston 9. The transverse hole 24 is transversely provided on the end face of the third piston 10. The through groove 25 adopts a circular groove structure. The through groove 25 extends along the end face of the third piston 10 toward the middle part of the third piston 10. The through groove 25 is connected with the delivery channel 11 through the transverse hole 24 to facilitate the delivery of oil to the delivery channel 11 through the through groove 25 and the transverse hole 24. A sealing gasket 26 is provided between the second piston 9 and the bottom shell 7. The sealing gasket 26 is installed on the bottom shell 7. The sealing gasket 26 is fixedly sealed and sleeved between the bottom cylinder 8 and the inner cylinder 6 to prevent the oil from leaking from the bottom end of the bottom cylinder 8. A sleeve groove 27 is provided on the side of the sealing gasket 26 close to the second piston 9. The sleeve groove 27 is provided in the middle part of the end face of the sealing gasket 26 so that the oil can be used to apply pressure to the bottom face of the second piston 9.

[0033] Please participate again Figure 3 A transverse groove 28 is provided on the outer cylinder 1 above the return oil port 5. The transverse groove 28 is provided on the inner wall of the outer cylinder 1. A sealing ring 29 made of elastic material is interference fit in the transverse groove 28. The sealing ring 29 is interference fit on the middle cylinder 2, thereby sealing the inner cavity of the outer cylinder 1 to prevent oil from leaking from the top of the outer cylinder 1.

[0034] Please refer again Figure 1 The outer cylinder 1 is provided with a handle 30, one side of which is mounted on the outer wall of the outer cylinder 1. The handle 30 is held to facilitate carrying the present invention. The first piston 3 is slidingly sealed and sleeved in the outer cylinder 1. The first piston 3 and the middle cylinder 2 are an integrated structure. The oil outlet 4 is located between the bottom cylinder 8 and the first piston 3, so that it is convenient to add oil to the bottom cylinder 8 through the oil outlet 4.

[0035] According to the above-mentioned method of using the prestressed tensioning jack, Figure 1-7 As shown, the following steps are included: S1, take out the oil pump and the prestressed tensioning jack, place the oil pump on one side of the prestressed tensioning jack, then connect the cylinder oil port 4 with the oil outlet of the oil pump by using a high-pressure hose, and connect the cylinder oil port 5 with the oil return port of the oil pump by using another high-pressure hose to complete the assembly of the oil pump and the prestressed tensioning jack; S2, control the middle cylinder 2 to move toward the bottom cylinder 8 by controlling the operating valve of the oil pump, thereby driving the top anchor pipe 17 to move toward the clamp 16, so as to drive the clamp 16 toward Move in the direction away from the anchor ring 15 to complete the preparation work; S3, move the oil pump and the prestressed tensioning jack into the working area, insert the prestressed tendons to be tensioned into the inner cylinder 6, and make the head 18 contact the anchor cable anchor installed on the prestressed tendons, and control the operating valve of the oil pump to transport the oil toward the cylinder oil port 4, thereby pushing the first piston 3, the middle cylinder 2, the top anchor pipe 17 and the head 18 to move along the inner wall of the outer cylinder 1 in the direction away from the bottom cylinder 8. At the same time, under the extrusion of the spring 14, Push the pressure ring 20 and several clips 16 to move toward the anchor ring 15 to anchor and fix the prestressed tendon in the anchor ring 15, thereby applying a tensioning force to the prestressed tendon; S4, as the oil pressure delivered by the oil pump continues to increase, the oil entering the outer cylinder 1 pushes the second piston 9 and the third piston 10 to move toward the first piston 3, thereby exerting a squeezing force on the first piston 3 and the middle cylinder 2 to increase the tensioning force of the prestressed tendon anchor, thereby improving the tensioning effect of the prestressed tendon; S5, after the prestressed tendon is tensioned, reverse the operation valve of the oil pump so that the oil moves toward The oil is delivered to the return cylinder oil port 5, pushing the first piston 3, the middle cylinder 2, the top anchor pipe 17 and the top head 18 to reset, thereby driving the top anchor pipe 17 to move in the direction close to the clamp 16, and squeezing the clamp 16 to move in the direction away from the anchor ring 15 to release the anchoring of the prestressed tendon. At the same time, the second piston 9 and the third piston are driven to reset by the first piston 3; S6, close the operating valve of the oil pump, remove the prestressed tensioning jack from the prestressed tendon, so that the prestressed tensioning jack and the oil pump can be used again to tension the prestressed tendon.

[0036] It should be noted that after the oil pump and the prestressed tensioning jack are assembled, the hydraulic system between the oil pump and the prestressed tensioning jack equipment should be checked for leakage. The oil pump operating valve is controlled to deliver oil toward the cylinder oil port 4 or the cylinder oil port 5, and the oil pump, the prestressed tensioning jack and the high-pressure hose are observed to see if there is any leakage. If there is any leakage, the oil pump operating valve is closed first, and then the leakage is maintained to ensure the safety of using the oil pump and the prestressed tensioning jack.

[0037] In this embodiment, the first piston 3 is arranged in the outer cylinder 1 to convert the pressure of the oil into a tensioning force, and a delivery channel 11 is created between the inner cylinder 6 and the second piston 9, so that the high-pressure oil can push the second piston 9 toward the first piston 3 to increase the applied stress, thereby improving the tensioning effect. The third piston 10 is slidingly sealed and sleeved in the outer cylinder 1 to prevent the oil from flowing between the outer cylinder 1 and the third piston 10, and to restrict the oil from being transported through the delivery channel 11. The bottom cylinder 8 above the second piston 9 is connected to the outside world through the pressure relief hole opened on the outer wall of the bottom cylinder 8, so as to prevent the air pressure in the outer cylinder from hindering the second piston 2 from converting the pressure into a tensioning force, thereby improving the stability of the tensioning effect.

[0038] The embodiments described above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Therefore, any equivalent changes or modifications made according to the structures, features and principles described in the patent scope of the present invention should be included in the scope of the patent application of the present invention.

Claims

1. A prestressed tensioning jack, comprising an outer cylinder (1), a middle cylinder (2) arranged in the outer cylinder (1), a first piston (3) arranged at the bottom of the middle cylinder (2), and the outer cylinder (1) on both sides of the first piston (3) are respectively provided with a cylinder oil outlet (4) and a cylinder oil return port (5), characterized in that: An inner cylinder (6) is arranged in the middle cylinder (2), the first piston (3) is slidingly and sealingly sleeved on the inner cylinder (6), a bottom shell (7) is arranged at the bottom of the inner cylinder (6), and a pressurizing mechanism is arranged on the bottom shell (7); The booster mechanism comprises a bottom cylinder (8) arranged below the outer cylinder (1), a second piston (9) with a sliding seal sleeve inside the bottom cylinder (8), and a third piston (10) with a sliding seal sleeve inside the outer cylinder (1); the second piston (9) and the third piston (10) are an integrated structure; the second piston (9) and the third piston (10) are both movably sleeved on the inner cylinder (6); the inner cylinder (6) and the second piston (9) and the third piston (10) form a delivery channel (11); the oil outlet (4) is connected to the inner cavity of the outer cylinder (1) through the inner cavity of the bottom cylinder (8) and the delivery channel (11); A pressure relief hole (12) is provided on the outer wall of the bottom cylinder (8), and the pressure relief hole (12) is located above the second piston (9).

2. The prestressed tensioning jack according to claim 1, characterized in that: A pressurizing device body (13) is provided on the side of the inner cylinder (6) away from the bottom shell (7); the pressurizing device body (13) and the inner cylinder (6) are an integral structure; and a pressurizing mechanism is provided on the pressurizing device body (13); The pressing mechanism comprises a spring (14) arranged in a pressing device body (13), an anchor ring (15) arranged at one end of the pressing device body (13) away from the inner cylinder (6), and a plurality of clips (16) movably mounted in the anchor ring (15); the anchor ring (15) is mounted on the pressing device body (13); the inner cavity of the anchor ring (15) adopts a conical groove structure; the outer shapes of the plurality of clips (16) are consistent with the inner cavity shape of the anchor ring (15); and the plurality of clips (16) are squeezed and fixed in the anchor ring (15) by the spring (14).

3. The prestressed tensioning jack according to claim 2, characterized in that: A top anchor tube (17) is provided on the side of the clip (16) away from the spring (14), and the top anchor tube (17) is movably sleeved in the anchor ring (15). One side of the top anchor tube (17) is in contact with the clip (16), and a top head (18) is provided on the other side of the top anchor tube (17). The top anchor tube (17) is connected to the middle cylinder (2) via the top head (18); a pressing sleeve (19) is sleeved inside the spring (14), and a pressing ring (20) is provided at one end of the pressing sleeve (19). The pressing ring (20) and the pressing sleeve (19) are an integral structure, and the pressing ring (20) is located between the spring (14) and the clip (16). Both sides of the spring (14) are in contact with the inner cylinder (6) and the pressing ring (20) respectively.

4. The prestressed tensioning jack according to claim 1, characterized in that: The inner diameter of the outer cylinder (1) and the inner diameter of the sump (8) The relationship between them should satisfy Formula 1, which is ,in is the coefficient of applied force, .

5. The prestressed tensioning jack according to claim 1, characterized in that: The top of the bottom cylinder (8) is mounted on the bottom of the outer cylinder (1); the pressure relief hole (12) is internally threadedly sleeved with a cover (21); a fixing groove (22) and a venting groove (23) are respectively provided on the cover (21); the pressure relief hole (12) is connected to the bottom cylinder (8) via the venting groove (23); the fixing groove (22) has a polygonal groove structure; the fixing groove (22) is provided on a side of the cover (21) away from the inner cylinder (6).

6. The prestressed tensioning jack according to claim 1, characterized in that: The third piston (10) is provided with a transverse hole (24) and a through groove (25) at one end away from the second piston (9). The transverse hole (24) is transversely formed on the end surface of the third piston (10). The through groove (25) is of an annular groove structure. The through groove (25) extends along the end surface of the third piston (10) toward the middle of the third piston (10). The through groove (25) is connected to the delivery channel (11) through the transverse hole (24). A sealing gasket (26) is provided between the second piston (9) and the bottom shell (7). The sealing gasket (26) is mounted on the bottom shell (7). The sealing gasket (26) is fixedly sealed and sleeved between the bottom cylinder (8) and the inner cylinder (6). A sleeve groove (27) is provided on the side of the sealing gasket (26) close to the second piston (9). The sleeve groove (27) is provided in the middle of the end surface of the sealing gasket (26).

7. The prestressed tensioning jack according to claim 1, characterized in that: A transverse groove (28) is provided on the outer cylinder (1) above the return oil port (5). The transverse groove (28) is provided on the inner wall of the outer cylinder (1). A sealing ring (29) made of elastic material is interference fit in the transverse groove (28). The sealing ring (29) is interference fit on the middle cylinder (2).

8. The prestressed tensioning jack according to claim 1, characterized in that: The outer cylinder (1) is provided with a handle (30), one side of the handle (30) is mounted on the outer wall of the outer cylinder (1), the first piston (3) is slidingly sealed and sleeved in the outer cylinder (1), the first piston (3) and the middle cylinder (2) are an integral structure, and the cylinder oil outlet (4) is located between the bottom cylinder (8) and the first piston (3).

9. The method for using the prestressed tensioning jack according to claim 3, characterized in that: The following steps are included: S1. Take out the oil pump and the prestressed tensioning jack, place the oil pump on one side of the prestressed tensioning jack, then connect the oil outlet port (4) of the cylinder with the oil outlet port of the oil pump by using a high-pressure rubber hose, and connect the oil return port (5) of the cylinder with the oil return port of the oil pump by using another high-pressure rubber hose, so as to complete the assembly of the oil pump and the prestressed tensioning jack; S2, by controlling the operating valve of the oil pump, the middle cylinder (2) is controlled to move toward the bottom cylinder (8), thereby driving the top anchor pipe (17) to move toward the clamping piece (16), thereby driving the clamping piece (16) to move in a direction away from the anchor ring (15), thereby completing the preparation operation; S3, moving the oil pump and the prestressing tensioning jack together into the working area, inserting the prestressed tendon to be tensioned into the inner cylinder (6), and making the top head (18) contact the anchor cable anchor installed on the prestressed tendon, and controlling the operating valve of the oil pump so that the oil is transported toward the oil outlet (4) of the cylinder, thereby pushing the first piston (3), the middle cylinder (2), the top anchor pipe (17) and the top head (18) to move along the inner wall of the outer cylinder (1) in a direction away from the bottom cylinder (8). At the same time, under the squeezing action of the spring (14), the pressure ring (20) and the plurality of clips (16) are pushed toward the anchor ring (15) to anchor and fix the prestressed tendon in the anchor ring (15), thereby applying a tensioning force to the prestressed tendon; S4. As the oil pressure delivered by the oil pump continues to increase, the oil entering the outer cylinder (1) pushes the second piston (9) and the third piston (10) to move toward the first piston (3), thereby exerting a squeezing force on the first piston (3) and the middle cylinder (2), thereby increasing the tensioning force of the prestressed tendon anchor, thereby improving the tensioning effect of the prestressed tendon; S5. After the prestressed tendon is tensioned, the operating valve of the oil pump is operated in the reverse direction so that the oil is transported toward the return cylinder oil port (5), pushing the first piston (3), the middle cylinder (2), the top anchor pipe (17) and the top head (18) to reset, thereby driving the top anchor pipe (17) to move toward the direction close to the clamping piece (16), and squeezing the clamping piece (16) to move toward the direction away from the anchor ring (15), so as to release the anchoring of the prestressed tendon. At the same time, the second piston (9) and the third piston are driven to reset through the first piston (3); S6. Close the operating valve of the oil pump and remove the prestressed tensioning jack from the prestressed tendon so that the prestressed tensioning jack and the oil pump can be used again to tension the prestressed tendon.

10. The method for using the prestressed tensioning jack according to claim 9, characterized in that: After the oil pump and the prestressed tensioning jack are assembled, the hydraulic system between the oil pump and the prestressed tensioning jack should be checked for leakage. The oil pump operating valve is controlled to deliver oil to the cylinder oil outlet (4) or the cylinder oil return port (5). The oil pump, the prestressed tensioning jack and the high-pressure rubber hose are observed to see if there is leakage. If there is leakage, the oil pump operating valve is closed first, and then the leaking part is maintained to ensure the safety of the oil pump and the prestressed tensioning jack.

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