A pretensioning method prestressed precast beam preparation equipment and method

Abstract

The application relates to the technical field of precast beam preparation, and discloses a pretensioning prestressed precast beam preparation device and method, which comprises a pedestal, fixed crossbeams, a movable crossbeam, a plurality of prestressed tendons and a jack, one side of one fixed crossbeam is provided with sliding rails, rollers are arranged in the movable crossbeam, one side of the rollers is provided with a driving main shaft, strip-shaped friction plates are arranged on the two sides of the sliding rails, a ring-shaped turntable is symmetrically arranged on the driving main shaft, a plurality of rectangular frames are arranged on the ring-shaped turntable, a driving part is arranged in the rectangular frame, a partition plate is further arranged below the ring-shaped turntable, a fixed plate frame is arranged on the partition plate, a friction block is arranged on one side of the fixed plate frame, and the pretensioning prestressed precast beam preparation device is linked through a centrifugal force and a friction brake mechanism; when the movable crossbeam moves too fast, the moving sliding block on the ring-shaped turntable drives the arc-shaped plate frame to move under the action of the centrifugal force, the friction block is triggered to contact the strip-shaped friction plate through the connecting part, and relevant braking force is generated.

Description

Technical Field

[0001] This invention relates to the field of precast beam manufacturing technology, specifically to a prestressed precast beam manufacturing equipment and method using the pre-tensioning method. Background Technology

[0002] Prestressed precast beams are load-bearing components in civil engineering formed by pre-tensioning steel bars to generate prestress before pouring concrete. The core principle is to use the elastic recoil of the steel bars to apply prestress to the concrete, thereby improving the crack resistance and load-bearing capacity of the beam. This process is widely used in the production of standardized components in bridges, buildings and other fields, such as hollow slab beams and T-beams, due to its convenient construction and stable structural performance. The preparation of prestressed precast beams mainly relies on a long-line pedestal system. Its basic process includes the installation of prestressing tendons, tensioning, formwork installation, concrete pouring and curing, release of prestressing tendons and component cutting. Specifically, the process begins by fixing one end of the prestressing tendon to a fixed crossbeam using clamps, and the other end passing through another fixed crossbeam and connecting to a movable crossbeam. Then, jacks on the movable crossbeam are activated, pushing it away from the fixed crossbeams, stretching the prestressing tendon to its designed length and generating prestress. Next, formwork is installed, ordinary reinforcing bars are tied, concrete is poured, and curing is performed. Once the concrete reaches its designed strength, the clamps on the fixed crossbeams are released, allowing the prestressing tendons to retract and applying prestress to the concrete. Finally, excess prestressing tendons are cut to complete the precast beam production. However, the speed control of the movable crossbeam primarily relies on manual operation of hydraulic valves, with workers adjusting the hydraulic supply speed of the jacks based on experience. The manual control method of using a rate to control the moving speed is easily affected by factors such as operator proficiency and reaction speed. During tensioning or releasing, the problem of excessive speed of the moving crossbeam often occurs. For example, if the worker fails to reduce the oil supply flow in time during tensioning, the moving crossbeam may exceed the preset stroke in a short period of time, causing the prestressed tendons to bear excessive tension instantaneously. During releasing, if the jack controls the retraction speed of the moving crossbeam too fast, it will generate a large impact load, which may not only damage the anchoring clamps and pedestal structure, but also cause stress concentration inside the concrete, resulting in cracks and affecting the structural performance and service life of the precast beam. To address this, we propose a pre-tensioned prestressed precast beam preparation equipment and method. Summary of the Invention

[0003] The purpose of this invention is to provide a prestressed precast beam preparation equipment and method using the pre-tensioning method to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a prestressed precast beam preparation device using the pretensioning method, comprising a platform, fixed crossbeams fixedly installed at both ends of the platform, a movable crossbeam provided on one side of one of the fixed crossbeams, multiple prestressing tendons installed between the fixed crossbeams, and jacks symmetrically installed between the movable crossbeam and the fixed crossbeam, a slide rail symmetrically provided on one side of one of the fixed crossbeams located below the movable crossbeam, and rollers symmetrically arranged inside the movable crossbeam that limit sliding inside the slide rail, and a drive spindle provided on one side of the rollers, and a speed-changing mechanism provided between the rollers and the drive spindle; Each slide rail has strip-shaped friction plates fixedly installed on both sides. An annular turntable is symmetrically installed on the drive spindle, with the annular turntable symmetrically installed on the drive spindle with the center line of the roller as the axis. Multiple rectangular frames are fixedly installed on the annular turntable, and a drive unit is provided inside the rectangular frame. A partition plate is also provided below the annular turntable and fixedly installed on the movable crossbeam. A fixed plate frame is fixedly installed on the partition plate. A friction block is provided on one side of the fixed plate frame, and the friction block is close to the strip-shaped friction plate. A connecting part is provided between the friction block and the drive unit.

[0005] Preferably, the driving unit includes a movable slider installed inside a rectangular frame, the movable slider being limited to slide within the rectangular frame, and an extension shaft being fixedly installed on the movable slider. The end of the extension shaft passes through the side wall of the rectangular frame and extends to the outside, and an arc-shaped plate frame is fixedly installed at the end of the extension shaft located outside the rectangular frame. A spring body is connected between the movable slider and the inner wall of the rectangular frame, and the spring body is sleeved on the extension shaft.

[0006] Preferably, the connecting part includes a positioning sleeve, a rotary sleeve, a positioning shaft, and an arc-shaped groove; The positioning sleeve is fixedly installed on the partition, and a spring mechanism is installed on the top of the positioning sleeve; The rotary sleeve is mounted on the positioning sleeve, and the bottom of the rotary sleeve is located inside the positioning sleeve and can move within the positioning sleeve. The top of the rotary sleeve is in contact with the spring mechanism, and the top of the rotary sleeve is also located on the movement trajectory of the arc-shaped plate frame. The positioning shaft is installed inside the rotary sleeve and is rotatably connected to the rotary sleeve. The positioning shaft is slidably connected to the partition plate. A torsion spring is connected between the positioning shaft and the bottom of the rotary sleeve. The arc-shaped groove is located inside the positioning shaft.

[0007] Preferably, the inner wall of the positioning sleeve is symmetrically equipped with a plurality of arc-shaped protrusions, one side of which is an arc-shaped surface and the other side is a right-angled surface. The outer wall of the rotary sleeve is symmetrically equipped with a telescopic shaft, and the end of the telescopic shaft is embedded with a ball bearing. The ball bearing at the end of the telescopic shaft contacts the arc-shaped surface of the arc-shaped protrusion during the descent process.

[0008] Preferably, a support sleeve is also fixedly installed on the partition plate. A rotating panel is installed inside the support sleeve and rotatably connected to its inner wall. A connecting shaft is fixedly installed on the rotating panel. The end of the connecting shaft is located inside the positioning shaft. A plurality of balls are movably installed on the outer wall of the connecting shaft, and the balls can slide within the arc-shaped groove.

[0009] Preferably, a fixed panel is fixedly installed inside the support sleeve, wherein the fixed panel is provided with multiple through slots, and multiple strong magnets are fixedly installed on the rotating panel. During the rotation of the rotating panel, the strong magnets will pass through the through slots. Below the fixed panel, there is also an iron plate frame that is slidably connected to the inner wall of the support sleeve. A support shaft with its end penetrating the inner wall of the support sleeve and extending to the outside is fixedly installed on the iron plate frame. A plastic spring sleeved on the support shaft is connected between the iron plate frame and the inner wall of the support sleeve. A trapezoidal slider one is fixedly installed at the end of the support shaft. A trapezoidal slider two is installed on the fixed plate frame and slidably connected to its inner wall. The trapezoidal slider two is located on the movement trajectory of the trapezoidal slider one. The friction block is fixedly installed on the trapezoidal slider two. Multiple return springs are connected between the trapezoidal slider two and the fixed plate frame.

[0010] Preferably, a force-bearing frame is fixedly installed on the top of the rotary sleeve, and an action frame is fixedly installed at both ends of the slide rail. The action frame is located on the movement trajectory of the force-bearing frame. When the movable crossbeam moves to the end of the slide rail, the action frame will contact the force-bearing frame and apply force to it. The rotary sleeve drives the telescopic shaft to rotate, and the end of the telescopic shaft rotates without contacting the arc-shaped protrusion.

[0011] Preferably, a strip frame is fixedly installed on one side of each of the fixed crossbeams, and a plurality of square sliders are installed inside the strip frame and slidably connected to its inner wall. Limiting sleeves are fixedly installed at the top and bottom of the square sliders. A pressing shaft is installed inside the limiting sleeve. The end of the pressing shaft penetrates the inner wall of the strip frame and extends to the outside. A constant force spring is connected between the pressing shaft and the inner wall of the limiting sleeve.

[0012] Preferably, the inner walls of the strip frame are symmetrically equipped with snap-fit ​​blocks at the top and bottom, and the outer walls of the pressing shaft are symmetrically equipped with snap-fit ​​shafts. When the snap-fit ​​shafts are between the snap-fit ​​blocks, the pressing shafts cannot move. The outer walls of the strip frame are also provided with scale grooves.

[0013] A method for using a prestressed precast beam fabrication equipment using the pre-tensioning method includes the following steps: S1. Installation and fixing of prestressed tendons: Determine the installation position of the prestressed tendons, and then adjust the position of the square slider to ensure that the axis of the prestressed tendons is consistent with the moving direction of the movable crossbeam. That is, press down the pressing shaft on one of the fixed crossbeams to make the locking shaft separate from the locking blocks. Push the pressing shaft to the installation position of the prestressed tendons and then release it. The pressing shaft will reset under the action of the constant force spring, and the locking shaft will enter the locking blocks for limitation. Repeat this operation to adjust the square slider on the other fixed crossbeam so that the center lines of the corresponding square sliders of the two fixed crossbeams coincide. S2. Tensioning Process: Activate the jacks on the movable crossbeam to push it away from the fixed crossbeam, stretching the prestressed tendons to the designed length and generating prestress. During tensioning, the movement of the movable crossbeam causes the rollers to slide on the slide rails. The rollers, through a speed-changing mechanism, cause the drive shaft to rotate, which in turn causes the annular turntable to rotate synchronously. When the annular turntable rotates, the movable slider inside the rectangular frame moves towards the other end of the rectangular frame under the action of centrifugal force. Through the extension shaft, the arc-shaped plate frame moves synchronously. If the moving speed of the movable crossbeam is normal, the centrifugal force is less than the elastic force of the spring body and the spring mechanism, and the friction block does not contact the strip friction plate. If the speed is too fast, the centrifugal force overcomes the elastic force, causing the rotary sleeve to move. Through the linkage of the positioning shaft and the rotating panel, the friction block eventually contacts the strip friction plate to generate friction, reducing the speed of the movable crossbeam to a constant value. S3. Template installation, concrete pouring and curing: After the prestressed tendons are tensioned to the design length and stabilized, install the template and tie the ordinary steel bars, pour the concrete and cure it in accordance with the specifications to ensure that the concrete reaches the design strength. S4. Prestressed Tendon Release and Component Cutting: After the concrete reaches its design strength, the clamps on the fixed crossbeam are released, allowing the prestressed tendons to retract and apply prestress to the concrete. During the release process, the jack controls the retraction of the movable crossbeam. During retraction, the rollers slide on the slide rails. If the movable crossbeam moves too fast, the rollers, through the speed-changing mechanism, cause the drive shaft to rotate, driving the annular turntable to rotate synchronously. Centrifugal force overcomes the elastic force, causing the rotating sleeve to move. Through the linkage of the positioning shaft and the rotating panel, the friction block eventually contacts the strip friction plate, generating friction and reducing the speed of the movable crossbeam to a constant value. If the movable crossbeam moves at a normal speed, the centrifugal force is less than the elastic force of the spring body and the spring mechanism, and the friction block does not contact the strip friction plate. After the release is completed, the excess prestressed tendons are cut to complete the precast beam production.

[0014] Compared with the prior art, the beneficial effects of the present invention are: This invention achieves adaptive control of the speed of the moving crossbeam through the linkage mechanism of centrifugal force and friction braking. When the moving crossbeam moves too fast, the moving slider on the annular turntable drives the arc-shaped plate frame to move under the action of centrifugal force. The friction block is triggered to contact the strip friction plate through the connecting part, thereby generating the relevant braking force and avoiding the problem of prestressed tendon overload or concrete cracking caused by the lag of manual operation of hydraulic valve. This invention achieves precise alignment of prestressed tendons through a square slider and a pressing shaft. The square slider within the strip frame can be adjusted in position by the pressing shaft to ensure that the axis of the prestressed tendon is consistent with the moving direction of the movable crossbeam, effectively eliminating the problem of uneven prestress distribution caused by lateral force. At the same time, the cooperation between the snap-fit ​​block and the snap-fit ​​shaft enables rapid adaptation of prestressed tendons of various specifications. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a top view of the overall structure of the present invention; Figure 3 This is a schematic diagram of the internal structure of the movable crossbeam of the present invention; Figure 4 This is a schematic diagram of the speed-changing mechanism of the present invention; Figure 5 This is a schematic diagram of the drive spindle and rotating shaft structure of the present invention; Figure 6 This is a schematic diagram of the drive unit structure of the present invention; Figure 7 This is a schematic diagram of the connecting part structure of the present invention; Figure 8 This is a schematic diagram of the rotary sleeve and positioning sleeve structure of the present invention; Figure 9 This is a schematic diagram of the working and load-bearing rod structures of the present invention; Figure 10 This is a schematic diagram of the internal structure of the support sleeve of the present invention; Figure 11 This is a schematic diagram of the through-slot and powerful magnet structure of the present invention; Figure 12 This is a schematic diagram of the trapezoidal slider one and trapezoidal slider two of the present invention; Figure 13 This is a schematic diagram of the fixed crossbeam and strip frame structure of the present invention; Figure 14 This is a schematic diagram of the internal structure of the strip frame of the present invention; Figure 15 This is a schematic diagram of the square slider and limiting sleeve structure of the present invention.

[0016] In the diagram: 1. Base; 2. Fixed crossbeam; 3. Movable crossbeam; 31. Partition plate; 32. Fixed plate frame; 33. Friction block; 34. Trapezoidal slider II; 35. Return spring; 4. Prestressed tendon; 5. Jack; 6. Slide rail; 61. Strip friction plate; 62. Actuating rod frame; 7. Roller; 71. Drive spindle; 72. Annular turntable; 73. Rectangular frame; 8. Speed ​​changing mechanism; 81. Rotating shaft; 82. Main gear; 83. Driven gear; 9. Drive unit; 91. Moving slider; 92. Extension shaft; 93. Arc-shaped plate frame; 94. Spring body; 10. Connecting part; 101. Positioning sleeve; 102. Rotary sleeve; 103. Fixed... 104. Positioning shaft; 105. Arc-shaped groove; 106. Spring mechanism; 107. Torsion spring; 108. Arc-shaped protrusion; 109. Telescopic shaft; 1000. Force-bearing frame; 11. Support sleeve; 111. Rotating panel; 112. Connecting shaft; 113. Ball bearing; 114. Fixed panel; 115. Through groove; 116. Strong magnet; 12. Iron plate frame; 121. Supporting shaft; 122. Plastic spring; 123. Trapezoidal slider; 13. Strip frame; 131. Square slider; 132. Limiting sleeve; 133. Pressing shaft; 134. Constant force spring; 135. Snap-fit ​​block; 136. Snap-fit ​​shaft; 137. Scale groove. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see Figure 1-15 This invention provides a technical solution: a prestressed precast beam preparation device using the pre-tensioning method. This invention addresses the technical problems in the background art by controlling the movement speed of the movable crossbeam during tensioning or detensioning to avoid quality problems in the precast beam caused by excessive movement speed of the movable crossbeam. The device includes a platform 1, fixed crossbeams 2 fixedly installed at both ends of the platform 1, and a movable crossbeam 3 on one side of one of the fixed crossbeams 2. Figure 1 Appendix Figure 2 Appendix Figure 3 and attached Figure 4As shown, both the fixed crossbeams 2 and the movable crossbeam 3 have strip-shaped grooves. In actual operation, the prestressing tendons 4 pass through the strip-shaped grooves on the fixed crossbeams 2 and the movable crossbeam 3, and are then fixed with clamps. Since the prestressing tendons 4 need to be cut after tensioning and untensioning, in order to save material, steel bars are usually used to replace the cut parts of the prestressing tendons 4, i.e., combined with... Figure 1 and attached Figure 2 As shown, the prestressing tendon 4 is located between the two fixed crossbeams 2. The steel bar is the part that ultimately contacts the strip groove on the fixed crossbeam 2 and the movable crossbeam 3. The steel bar is then fixed with a clamp. After the tensioning is completed, the steel bar is cut off, and the prestressing tendon 4 remains in the precast beam. The steel bar and the prestressing tendon 4 are connected by a connector. It should be noted that the above-mentioned technologies are all prior art, and therefore, this invention will not describe them in detail. As for the steel bar, prestressing tendon 4, and connectors, this invention uses the term prestressing tendon 4 to uniformly replace them in the following description; combined with the appendix Figure 1 and attached Figure 2 As shown, jacks 5 are symmetrically installed between the movable crossbeam 3 and the fixed crossbeam 2. A slide rail 6 located below the movable crossbeam 3 is symmetrically arranged on one side of one of the fixed crossbeams 2. Rollers 7, which slide within the slide rail 6, are symmetrically arranged inside the movable crossbeam 3 and are limited in their sliding motion. A drive spindle 71 is arranged on one side of the roller 7. A speed-changing mechanism 8 is arranged between the roller 7 and the drive spindle 71. As a further limitation of this invention, in conjunction with the attached... Figure 3 Appendix Figure 4 and attached Figure 5 As shown, the speed changing mechanism 8 includes a rotating shaft 81 rotatably connected to the movable crossbeam 3, a roller 7 fixedly mounted on the rotating shaft 81, a main gear 82 fixedly mounted at one end of the rotating shaft 81, and a driven gear 83 meshing with the main gear 82 fixedly mounted on the drive shaft 71. The radius and number of teeth of the main gear 82 are much larger than the radius and number of teeth of the driven gear 83. The specific speed changing ratio can be set according to the actual situation on site. Strip-shaped friction plates 61 are fixedly installed on both sides of each slide rail 6. Annular turntables 72 are symmetrically installed on the drive spindle 71. The two annular turntables 72 are symmetrically installed on the drive spindle 71 with the center line of the roller 7 as the axis. Multiple rectangular frames 73 are fixedly installed on the annular turntables 72. A drive unit 9 is provided inside the rectangular frame 73. When the drive spindle 71 rotates, the drive unit 9 will move within the rectangular frame 73 under the action of centrifugal force. A partition plate 31 is also fixedly installed on the movable crossbeam 3 below the annular turntable 72. A fixed plate frame 32 is fixedly installed on the partition plate 31. A friction block 33 is provided on one side of the fixed plate frame 32. The friction block 33 is close to the strip-shaped friction plate 61. A connecting part 10 is provided between the friction block 33 and the drive unit 9.

[0019] Combined with appendix Figure 5 and attached Figure 6 As shown, as a further limitation of the present invention, the driving unit 9 includes a movable slider 91 installed within a rectangular frame 73. The movable slider 91 slides within the rectangular frame 73 and is limited in its movement. An extension shaft 92 is also fixedly installed on the movable slider 91. The end of the extension shaft 92 penetrates the side wall of the rectangular frame 73 and extends to the outside. An arc-shaped plate frame 93 is fixedly installed at the end of the extension shaft 92 located outside the rectangular frame 73. A spring body 94 is connected between the movable slider 91 and the inner wall of the rectangular frame 73. The spring body 94 is sleeved on the extension shaft 92. Therefore, in actual application, when the roller 7 slides on the slide rail 6, the roller 7 will drive the rotating shaft 81 and its end... The main gear 82 rotates, meshing with the driven gear 83. The shifted driven gear 83 causes the drive shaft 71 to rotate, which in turn drives the annular turntable 72 on the drive shaft to rotate synchronously. During the rotation of the annular turntable 72, the movable slider 91 inside the rectangular frame 73 is subjected to centrifugal force and moves to the other end of the rectangular frame 73. During the movement, the movable slider 91 compresses the spring body 94, and the movable slider 91 causes the arc-shaped plate frame 93 to move synchronously through the extension shaft 92. It should be noted that the spring body 94 is preferably made of a spring with a low elastic coefficient, so that the movable slider 91 can move under the action of centrifugal force.

[0020] Combined with appendix Figure 6 Appendix Figure 7 and attached Figure 8 As shown, as a further limitation of the present invention, the connecting part 10 includes a positioning sleeve 101 fixedly mounted on the partition 31, and a rotary sleeve 102 that can move within the positioning sleeve 101 is also mounted on the positioning sleeve 101. The bottom of the rotary sleeve 102 is located inside the positioning sleeve 101, and a spring mechanism 105 is provided between the top of the rotary sleeve 102 and the positioning sleeve 101. The spring mechanism 105 is mounted on the positioning sleeve 101, and the spring mechanism 105 is in contact with the top of the rotary sleeve 102. The rotary sleeve 102 is also located on the movement trajectory of the arc-shaped plate frame 93. When the arc-shaped plate frame 93 moves under the action of centrifugal force, the top of the rotary sleeve 102 will be subjected to force and slide inside the positioning sleeve 101. The positioning shaft 103 is also rotatably installed inside the rotary sleeve 102. The positioning shaft 103 is slidably connected to the partition plate 31, and a torsion spring 106 is connected between the positioning shaft 103 and the bottom of the rotary sleeve 102. An arc-shaped groove 104 is provided on the inner wall of the positioning shaft 103. Multiple arc-shaped protrusions 107 are symmetrically and fixedly installed on the inner wall of the positioning sleeve 101. These protrusions are equidistant from each other, with one side being an arc surface and the other a right-angled surface. A telescopic shaft 108 is symmetrically installed on the outer wall of the rotating sleeve 102, with ball bearings embedded at its ends. During descent, the ball bearings contact the arc surface of the arc-shaped protrusions 107. A force-bearing frame 109 is fixedly installed on the top of the rotating sleeve 102, and actuating frames 62 are fixedly installed at both ends of the slide rail 6. The actuating frames 62 are located on the movement trajectory of the force-bearing frame 109. When the movable crossbeam 3 moves... When the slide rail 6 is moved to the end of the slide rail 6, the action rod 62 at the end of the slide rail 6 will contact the force-bearing rod 109 and apply force to it. The rotating sleeve 102 drives the telescopic shaft 108 to rotate. The end of the telescopic shaft 108 rotates without contacting the arc-shaped protrusion 107. A support sleeve 11 is also fixedly installed on the partition plate 31. A rotating panel 111 is installed inside the support sleeve 11 and is rotatably connected to its inner wall. A connecting shaft 112 is fixedly installed on the rotating panel 111. The end of the connecting shaft 112 is located inside the positioning shaft 103. Multiple balls 113 are movably installed on the outer wall of the connecting shaft 112, and the balls 113 can slide within the arc-shaped groove 104. Combined with appendix Figure 9 Appendix Figure 10 and appendix Figure 11 As shown, a fixed panel 114 is fixedly installed inside the support sleeve 11. The fixed panel 114 has multiple through slots 115, and a multiple powerful magnet 116 is fixedly installed on the rotating panel 111. During the rotation of the rotating panel 111, the powerful magnets 116 pass through the through slots 115. When the moving beam 3 moves at a normal speed, the powerful magnets 116 will not move to the through slots 115, meaning the fixed panel 114 blocks the powerful magnets 116. Below the fixed panel 114, an iron plate frame 12 is slidably connected to the inner wall of the support sleeve 11. A support shaft 121 with its end penetrating the inner wall of the support sleeve 11 and extending to the outside is also fixedly installed on the support shaft 121. A plastic spring 122 sleeved on the support shaft 121 is connected between the iron plate frame 12 and the inner wall of the support sleeve 11. A trapezoidal slider 123 is fixedly installed at the end of the support shaft 121. A trapezoidal slider 2 34 that is slidably connected to the inner wall of the fixed plate frame 32 is installed on the fixed plate frame 32. The trapezoidal slider 2 34 is located on the movement trajectory of the trapezoidal slider 123. A friction block 33 is fixedly installed on the trapezoidal slider 2 34. Multiple return springs 35 are connected between the trapezoidal slider 2 34 and the fixed plate frame 32.

[0021] Furthermore, during the actual tensioning or untensioning process, the jack 5 controls the movement or retraction of the movable crossbeam 3. During the movement of the movable crossbeam 3, the roller 7, which contacts the slide rail 6, rotates. This, in turn, causes the main gear 82 to rotate in engagement with the driven gear 83 under the action of the rotating shaft 81. The shifted driven gear 83 then causes the drive shaft to rotate, which in turn drives the annular turntable 72 to rotate synchronously. During the rotation of the annular turntable 72, the movable slider 91 within the rectangular frame 73 is subjected to centrifugal force and exhibits a tendency to move. Therefore, when the moving speed of the movable crossbeam 3 is normal, the centrifugal force on the movable slider 91 will be small. The spring body 94 and the spring mechanism 105 exert their elastic force. However, if the moving speed of the movable crossbeam 3 is too fast, the centrifugal force on the moving slider 91 will increase, thereby overcoming the elastic force of the spring body 94 and the spring mechanism 105 and moving towards the other end of the rectangular frame 73. During the movement, the moving slider 91 will compress the spring body 94, and the moving slider 91 will cause the arc-shaped plate frame 93 to move synchronously through the extension shaft 92. The movement of the arc-shaped plate frame 93 will act on the rotating sleeve 102 on the positioning sleeve 101, thereby causing the rotating sleeve 102 to move into the positioning sleeve 101. During the movement, the rotating sleeve 102 will act on the spring body 94. When the spring mechanism 105 compresses, and the rotary sleeve 102 moves, the telescopic shaft 108 on its outer wall moves along the arc-shaped surface of the arc-shaped protrusion 107. During the movement of the arc-shaped surface, the telescopic shaft 108 retracts, and when it passes the right-angle surface, the telescopic shaft 108 returns to its original position. During the movement of the rotary sleeve 102, the positioning shaft 103 inside moves synchronously with it, so that the arc-shaped groove 104 on the inner wall of the positioning shaft 103 applies a force to the multiple balls 113 on the outer wall of the connecting shaft 112. That is, the balls 113 are subjected to a force that causes the connecting shaft 112 to rotate, thereby causing the connecting shaft 112 to drive the rotating surface. As the plate 111 rotates, the powerful magnet 116 on it rotates to the through slot 115, thereby generating a repulsive force on the iron plate frame 12 below. The iron plate frame 12 is subjected to the repulsive force and moves downward. During the descent, it compresses the plastic spring 122. The support shaft 121 on the iron plate frame 12 drives the trapezoidal slider 123 to act on the trapezoidal slider 24, thereby causing the trapezoidal slider 24 to slide at the upper limit of the fixed plate frame 32 and stretch the return spring 35. The friction block 33 will contact the strip friction plate 61 under the action of the trapezoidal slider 24. Furthermore, when the roller 7 rotates at a higher speed, the meshing action of the main gear 82 and the driven gear 83 will increase the rotation speed of the drive shaft 71 and the annular turntable 72 on it. That is, the moving slider 91 moves a greater distance under the action of centrifugal force. As a result, under the action of the extension shaft 92 and the arc-shaped plate frame 93, the moving distance of the rotary sleeve 102 will increase accordingly. Consequently, the arc-shaped groove 104 on the inner wall of the positioning shaft 103 will act on the ball 113, increasing the rotation angle of the connecting shaft 112. This will increase the exposed area of ​​the strong magnet 116 on the rotating panel 111 at the through groove 115. Consequently, the repulsive force on the iron plate frame 12 will increase. To further explain, the fixed panel 1 14 is actually a plate frame that can isolate magnetic force, which increases the force of trapezoidal slider 123 on trapezoidal slider 234. That is, friction block 33 will be in close contact with strip friction plate 61, and the movement speed of movable beam 3 will be reduced. The contact pressure between friction block 33 and strip friction plate 61 is determined according to the movement speed of movable beam 3. Although the rotation speed of roller 7 is reduced, the arc plate frame 93 will retract under the action of spring body 94, and the telescopic shaft 108 on rotary sleeve 102 will be unable to reset due to the action of right angle surface of arc protrusion 107. Thus, rotary sleeve 102 will be in a stationary state, thereby making the speed of movable beam 3 constant. After tensioning or releasing, the movable crossbeam 3 moves to the end of the slide rail 6. Since the slide rail 6 is symmetrically equipped with actuating rods 62 at both ends, when the movable crossbeam 3 moves to the end of the slide rail 6, the actuating rods 62 apply a force to the force-bearing rods 109 on the rotating sleeve 102, causing the force-bearing rods 109 to drive the rotating sleeve 102 to rotate. Consequently, the torsion spring 106 between the rotating sleeve 102 and the positioning shaft 103 is in a deformable and stored state, while the telescopic shaft 108 on the outer wall of the rotating sleeve 102 moves away from the arc-shaped protrusion 107. At this time, the arc-shaped protrusion 107 is no longer moving with the telescopic shaft 108. On the trajectory, the rotating sleeve 102 will be reset under the action of the spring mechanism 105. It should be noted that the length of the actuating rod 62 is much greater than that of the force-bearing rod 109. Even after the rotating sleeve 102 is reset, the actuating rod 62 will still be in contact with the force-bearing rod 109. When the movable crossbeam 3 starts to move, the force-bearing rod 109 moves away from the actuating rod 62, and the rotating sleeve 102 will be reset under the action of the torsion spring 106. That is, the arc-shaped protrusion 107 is located on the movement trajectory of the telescopic shaft 108. During the movement of the rotating sleeve 102, the arc-shaped protrusion 107 will limit the movement direction of the telescopic shaft 108.

[0022] In practical applications, the dimensions, number of prestressing tendons 4, and position of prestressing tendons 4 vary among different precast beams. This can lead to the prestressing tendons 4 easily shifting when passing through the strip grooves on the fixed crossbeam 2 and the movable crossbeam 3. Specifically, there is an angular difference between the axial direction of the prestressing tendon 4 and the moving direction of the movable crossbeam 3. During tensioning or releasing, the prestressing tendon 4 is subjected to a lateral force, which increases linearly with the tension stress. When the moving speed of the movable crossbeam 3 is high, the lateral force exhibits periodic fluctuations, further amplifying the lateral shift of the prestressing tendon 4 and reducing the load-bearing capacity of the precast beam structure. Based on this, the present invention incorporates the following design: A strip frame 13 is fixedly installed on one side of each fixed crossbeam 2, and multiple square sliders 131 that are slidably connected to the inner wall of the strip frame 13 are installed inside the strip frame 13. The square sliders 131 have round holes for the prestressing tendons 4 to pass through. The clamps are fixed on the square sliders 131. Limiting sleeves 132 are fixedly installed at the top and bottom of the square sliders 131. A pressing shaft 133 is installed inside the limiting sleeve 132. The end of the pressing shaft 133 penetrates the inner wall of the strip frame 13 and extends to the outside. A constant force spring 134 is connected between the inner wall of the limiting sleeve 132 and the outer wall of the strip frame 13. A scale groove 137 is also provided on the outer wall of the strip frame 13. A pointer is also installed at the end of the pressing shaft 133 located outside the strip frame 13. The distance of movement of the square slider 131 can be known by the pointer. The top and bottom inner walls of the inner wall of the strip frame 13 are symmetrically installed with locking blocks 135. The outer wall of the pressing shaft 133 is symmetrically installed with locking shafts 136. When the locking shafts 136 are between the locking blocks 135, the pressing shaft 133 cannot move. Combined with appendix Figure 13 Appendix Figure 14 and attached Figure 15As shown, before installing the prestressing tendon 4, the installation position of the prestressing tendon 4 is first determined. After determining the installation position, the pressing shaft 133 on one of the fixed crossbeams 2 is pressed down, causing the pressing shaft 133 to move within the limiting sleeve 132, thus compressing the constant force spring 134. During the movement of the pressing shaft 133 inside the limiting sleeve 132, the locking shaft 136 on it will disengage from between the locking blocks 135. Then, the pressing shaft 133 is pushed to move it to the installation position of the prestressing tendon 4. Then, release the pressing shaft 133. The pressing shaft 133 is reset under the action of the constant force spring 134, that is, the locking shaft 136 enters between the locking blocks 135. The locking blocks 135 limit the locking shaft 136, so that the square slider 131 cannot move. According to the position of the square slider 131, press the pressing shaft 133 corresponding to the other fixed crossbeam 2. Repeat the above operation so that the center lines of the square sliders 131 on the two fixed crossbeams 2 coincide.

[0023] A method for using a prestressed precast beam fabrication equipment using the pre-tensioning method includes the following steps: S1. Installation and fixing of prestressing tendon 4: Determine the installation position of prestressing tendon 4, and then adjust the position of square slider 131 to ensure that the axial direction of prestressing tendon 4 is consistent with the moving direction of movable crossbeam 3. That is, press down on the pressing shaft 133 on one of the fixed crossbeams 2, so that the snap-fit ​​shaft 136 leaves between the snap-fit ​​blocks 135. Push the pressing shaft 133 to the installation position of prestressing tendon 4 and then release it. The pressing shaft 133 is reset under the action of constant force spring 134, and the snap-fit ​​shaft 136 enters the snap-fit ​​blocks 135 for limitation. Repeat this operation to adjust the square slider 131 on the other fixed crossbeam 2 so that the center lines of the corresponding square sliders 131 of the two fixed crossbeams 2 coincide. S2. Tensioning process: Start the jack 5 on the movable crossbeam 3 to push the movable crossbeam 3 away from the fixed crossbeam 2, so that the prestressed tendon 4 is stretched to the design length and generates prestress. During the tensioning process, the movement of the movable crossbeam 3 drives the roller 7 to slide on the slide rail 6. The roller 7 drives the drive shaft 71 to rotate through the speed changing mechanism 8, which in turn drives the annular turntable 72 to rotate synchronously. When the annular turntable 72 rotates, the movable slider 91 in the rectangular frame 73 moves to the other end of the rectangular frame 73 under the action of centrifugal force. Through the extension shaft 92, the arc plate frame 93 moves synchronously. If the moving speed of the movable crossbeam 3 is normal, the centrifugal force is less than the elastic force of the spring body 94 and the spring mechanism 105, and the friction block 33 does not contact the strip friction plate 61. If the speed is too fast, the centrifugal force overcomes the elastic force and causes the rotary sleeve 102 to move. Through the linkage of the positioning shaft 103 and the rotating panel 111, the friction block 33 finally contacts the strip friction plate 61 to generate friction, reducing the speed of the movable crossbeam 3 to a constant value. S3. Template installation, concrete pouring and curing: After the prestressed tendons are tensioned to the design length and stabilized, install the template and tie the ordinary steel bars, pour the concrete and cure it in accordance with the specifications to ensure that the concrete reaches the design strength. S4. Release of Prestressed Tendons 4 and Cutting of Components: After the concrete reaches the design strength, the clamps on the fixed crossbeam 2 are released, allowing the prestressed tendons 4 to retract and apply prestress to the concrete. During the release process, the jack 5 controls the retraction of the movable crossbeam 3. During the retraction, the roller 7 slides on the slide rail 6. If the movable crossbeam 3 moves too fast, the roller 7 drives the drive shaft 71 to rotate through the speed-changing mechanism 8, causing the annular turntable 72 to rotate synchronously. The centrifugal force overcomes the elastic force, causing the rotary sleeve 102 to move. Through the linkage of the positioning shaft 103 and the rotating panel 111, the friction block 33 finally contacts the strip friction plate 61 to generate friction, reducing the speed of the movable crossbeam 3 to a constant value. If the moving speed of the movable crossbeam 3 is normal, the centrifugal force is less than the elastic force of the spring body 94 and the spring mechanism 105, and the friction block 33 does not contact the strip friction plate 61. After the release is completed, the excess prestressed tendons 4 are cut to complete the production of the precast beam.

[0024] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0025] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A prestressed precast beam preparation device using the pre-tensioning method, comprising a platform (1), fixed crossbeams (2) fixedly installed at both ends of the platform (1), wherein a movable crossbeam (3) is also provided on one side of one of the fixed crossbeams (2), multiple prestressing tendons (4) are installed between the fixed crossbeams (2), and jacks (5) are symmetrically installed between the movable crossbeam (3) and the fixed crossbeam (2), characterized in that: One of the fixed crossbeams (2) is also symmetrically provided with a slide rail (6) located below the movable crossbeam (3) on one side, and the movable crossbeam (3) is symmetrically provided with rollers (7) that slide within the slide rail (6) and a drive spindle (71) is provided on one side of the rollers (7), and a speed changing mechanism (8) is provided between the rollers (7) and the drive spindle (71). Each of the slide rails (6) has a strip-shaped friction plate (61) fixedly installed on both sides. A ring turntable (72) is symmetrically installed on the drive spindle (71). The ring turntable (72) is symmetrically installed on the drive spindle (71) with the center line of the roller (7) as the axis. Multiple rectangular frames (73) are fixedly installed on the ring turntable (72). A drive unit (9) is provided inside the rectangular frame (73). A partition (31) is fixedly installed on the movable crossbeam (3) below the ring turntable (72). A fixed plate frame (32) is fixedly installed on the partition (31). A friction block (33) is provided on one side of the fixed plate frame (32). The friction block (33) is close to the strip-shaped friction plate (61). A connecting part (10) is provided between the friction block (33) and the drive unit (9).

2. The equipment for preparing prestressed precast beams using the pre-tensioning method according to claim 1, characterized in that: The drive unit (9) includes a movable slider (91) installed in a rectangular frame (73). The movable slider (91) slides within the rectangular frame (73) and an extension shaft (92) is fixedly installed on the movable slider (91). The end of the extension shaft (92) passes through the side wall of the rectangular frame (73) and extends to the outside. An arc-shaped plate frame (93) is fixedly installed at one end of the extension shaft (92) located outside the rectangular frame (73). A spring body (94) is connected between the movable slider (91) and the inner wall of the rectangular frame (73). The spring body (94) is sleeved on the extension shaft (92).

3. The equipment for preparing prestressed precast beams using the pre-tensioning method according to claim 2, characterized in that: The connecting part (10) includes a positioning sleeve (101), a rotating sleeve (102), a positioning shaft (103), and an arc-shaped groove (104). The positioning sleeve (101) is fixedly installed on the partition plate (31), and a spring mechanism (105) is installed on the top of the positioning sleeve (101). The rotary sleeve (102) is mounted on the positioning sleeve (101), and the bottom of the rotary sleeve (102) is located inside the positioning sleeve (101), and can be limited to move inside the positioning sleeve (101). The top of the rotary sleeve (102) is in contact with the spring mechanism (105), and the top of the rotary sleeve is also located on the movement trajectory of the arc plate frame (93). The positioning shaft (103) is installed inside the rotary sleeve (102) and is rotatably connected to the rotary sleeve (102). The positioning shaft (103) is slidably connected to the partition plate (31). A torsion spring (106) is connected between the positioning shaft (103) and the bottom of the rotary sleeve (102). The arc-shaped groove (104) is formed inside the positioning shaft (103).

4. The equipment for preparing prestressed precast beams using the pre-tensioning method according to claim 3, characterized in that: The inner wall of the positioning sleeve (101) is symmetrically equipped with multiple arc-shaped protrusions (107). One side of the arc-shaped protrusion (107) is an arc-shaped surface and the other side is a right-angled surface. The outer wall of the rotary sleeve (102) is symmetrically equipped with a telescopic shaft (108), and the end of the telescopic shaft (108) is embedded with a ball. The ball at the end of the telescopic shaft (108) contacts the arc-shaped surface of the arc-shaped protrusion (107) during the descent process.

5. The equipment for preparing prestressed precast beams using the pre-tensioning method according to claim 4, characterized in that: A support sleeve (11) is also fixedly installed on the partition (31). A rotating panel (111) is installed inside the support sleeve (11) and rotatably connected to its inner wall. A connecting shaft (112) is fixedly installed on the rotating panel (111). The end of the connecting shaft (112) is located inside the positioning shaft (103). A plurality of balls (113) are movably installed on the outer wall of the connecting shaft (112), and the balls (113) can slide within the arc-shaped groove (104).

6. The equipment for preparing prestressed precast beams using the pre-tensioning method according to claim 5, characterized in that: The support sleeve (11) has a fixed panel (114) fixedly installed inside, wherein the fixed panel (114) is provided with multiple through slots (115), and multiple strong magnets (116) are fixedly installed on the rotating panel (111). During the rotation of the rotating panel (111), the strong magnets (116) will pass through the through slots (115). Below the fixed panel (114), there is also an iron plate frame (12) that is slidably connected to the inner wall of the support sleeve (11). A support shaft (121) with its end penetrating the inner wall of the support sleeve (11) and extending to the outside is also fixedly installed on the iron plate frame (12). A plastic spring (122) sleeved on the support shaft (121) is connected between the iron plate frame (12) and the inner wall of the support sleeve (11). A trapezoidal slider one (123) is fixedly installed at the end of the support shaft (121). A trapezoidal slider two (34) that is slidably connected to the inner wall of the fixed plate frame (32) is installed on the fixed plate frame (32). The trapezoidal slider two (34) is located on the movement trajectory of the trapezoidal slider one (123). The friction block (33) is fixedly installed on the trapezoidal slider two (34). A plurality of return springs (35) are connected between the trapezoidal slider two (34) and the fixed plate frame (32).

7. The equipment for preparing prestressed precast beams using the pre-tensioning method according to claim 6, characterized in that: The top of the rotary sleeve (102) is also fixedly installed with a force-bearing rod (109), and both ends of the slide rail (6) are fixedly installed with an action rod (62). The action rod (62) is located on the movement trajectory of the force-bearing rod (109). When the movable crossbeam (3) moves to the end of the slide rail (6), the action rod (62) will contact the force-bearing rod (109) and apply force to it. The rotary sleeve (102) drives the telescopic shaft (108) to rotate. The end of the telescopic shaft (108) rotates and does not contact the arc-shaped protrusion (107).

8. A prestressed precast beam fabrication equipment according to any one of claims 1-7, characterized in that: Each of the fixed crossbeams (2) is fixedly installed with a strip frame (13) on one side, and a plurality of square sliders (131) are installed inside the strip frame (13) and slidably connected to its inner wall. Limiting sleeves (132) are fixedly installed at the top and bottom of the square sliders (131). A pressing shaft (133) is installed inside the limiting sleeve (132). The end of the pressing shaft (133) penetrates the inner wall of the strip frame (13) and extends to the outside. A constant force spring (134) is connected between the pressing shaft (133) and the inner wall of the limiting sleeve (132).

9. The equipment for preparing prestressed precast beams using the pre-tensioning method according to claim 8, characterized in that: The inner walls of the strip frame (13) are symmetrically fitted with snap-fit ​​blocks (135) at the top and bottom. The outer walls of the pressing shaft (133) are symmetrically fitted with snap-fit ​​shafts (136). When the snap-fit ​​shafts (136) are between the snap-fit ​​blocks (135), the pressing shafts (133) cannot move. The outer walls of the strip frame (13) are also provided with scale grooves (137).

10. A method for using a prestressed precast beam fabrication equipment, characterized in that: The prestressed precast beam fabrication equipment based on claim 9 specifically includes the following steps: S1. Installation and fixing of prestressed tendons (4): Determine the installation position of the prestressed tendons (4), and then adjust the position of the square slider (131) to ensure that the axis of the prestressed tendons (4) is consistent with the moving direction of the movable crossbeam (3). That is, press down the pressing shaft (133) on one of the fixed crossbeams (2) so that the snap-fit ​​shaft (136) leaves between the snap-fit ​​blocks (135). Push the pressing shaft (133) to the installation position of the prestressed tendons (4) and then release it. The pressing shaft (133) is reset under the action of the constant force spring (134), and the snap-fit ​​shaft (136) enters the snap-fit ​​blocks (135) for limit. Repeat this operation to adjust the square slider (131) on the other fixed crossbeam (2) so that the center lines of the square sliders (131) corresponding to the two fixed crossbeams (2) coincide. S2, Tensioning process: Start the jack (5) on the movable crossbeam (3) to push the movable crossbeam (3) away from the fixed crossbeam (2), so that the prestressed tendon (4) is stretched to the design length and generates prestress. During the tensioning process, the movable crossbeam (3) moves and drives the roller (7) to slide on the slide rail (6). The roller (7) drives the drive shaft (71) to rotate through the speed changing mechanism (8), which in turn drives the annular turntable (72) to rotate synchronously. When the annular turntable (72) rotates, the movable slider (91) in the rectangular frame (73) is subjected to centrifugal force and moves towards the rectangular frame ( 73) The other end moves, and the arc-shaped plate frame (93) moves synchronously through the extension shaft (92). If the moving speed of the movable crossbeam (3) is normal, the centrifugal force is less than the elastic force of the spring body (94) and the spring mechanism (105), and the friction block (33) does not contact the strip friction plate (61). If the speed is too fast, the centrifugal force overcomes the elastic force and moves the rotating sleeve (102). Through the linkage of the positioning shaft (103) and the rotating panel (111), the friction block (33) finally contacts the strip friction plate (61) to generate friction, reducing the speed of the movable crossbeam (3) to a constant value. S3. Template installation, concrete pouring and curing: After the prestressed tendons (4) are tensioned to the design length and stabilized, install the template and tie the ordinary steel bars, pour the concrete and cure it in accordance with the specifications to ensure that the concrete reaches the design strength. S4. Prestressing tendon (4) release and component cutting: After the concrete reaches the design strength, loosen the clamps on the fixed crossbeam (2) to allow the prestressing tendon (4) to retract and apply prestress to the concrete. During the release process, the jack (5) controls the retraction of the movable crossbeam (3). During the retraction process, the roller (7) slides on the slide rail (6). If the movable crossbeam (3) moves too fast, the roller (7) will rotate the drive shaft (71) through the speed changing mechanism (8), driving the annular turntable (72) to rotate synchronously. The centrifugal force overcomes the spring. Force causes the rotating sleeve (102) to move. Through the linkage of the positioning shaft (103) and the rotating panel (111), the friction block (33) finally comes into contact with the strip friction plate (61) to generate friction, reducing the speed of the moving beam (3) to a constant value. If the moving beam (3) moves at a normal speed, the centrifugal force is less than the elastic force of the spring body (94) and the spring mechanism (105), and the friction block (33) does not come into contact with the strip friction plate (61). After the tensioning is completed, the excess prestressing tendons (4) are cut to complete the production of the precast beam.

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