A demoulding device and method for a coverless rectangular concrete inner form

Abstract

The present application relates to a kind of no top rectangular concrete inner mold stripping device and stripping method, the device is divided into two corner molds and two L-shaped molds by innovative structural design, and is matched with the track of specific angle (45 ° in horizontal direction) extension arrangement and intermittent driving device.When stripping, intermittent driving device can first accurately drive two corner molds to slide inwards synchronously, effectively reduce the contact area and friction between inner mold and concrete, then drive two L-shaped molds to slide inwards synchronously, complete the whole stripping process.Compared with traditional stripping mode, it greatly improves the stripping efficiency and reduces the stripping time;Using this step-by-step stripping method, direct knocking and violent disassembly of the mold and concrete are avoided, effectively reducing the risk of damage to the inner mold and concrete, ensuring the surface integrity and internal structure strength of the concrete, prolonging the service life of the inner mold and reducing the production cost.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to a demolding device and method for a topless rectangular concrete inner mold. Background Technology

[0002] In building construction and the production of precast concrete components, the fabrication of open-top rectangular concrete structures is quite common. Traditional open-top rectangular concrete inner molds are mostly monolithic structures or employ simple splicing methods. With monolithic inner molds, the adhesion and friction between the concrete and the inner mold are extremely high during demolding, often requiring significant manpower and forced demolding methods such as hammering. This not only results in low demolding efficiency but also easily damages both the concrete and the inner mold, affecting the surface quality of the concrete and the number of times the inner mold can be reused. While simple splicing inner molds reduce demolding difficulty to some extent, the splicing and disassembly process is cumbersome and consumes a lot of time and effort. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the problems existing in the existing related technologies. To this end, the present invention proposes a demolding device and demolding method for a rectangular concrete inner mold without a top cover.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A demolding device for a rectangular concrete inner mold without a top cover includes a rectangular inner mold, which is divided into four templates, including two corner molds and two L-shaped molds. The two corner molds and the two L-shaped molds are arranged alternately around each other. A rectangular inner frame is provided inside the rectangular inner mold. Each of the four corners of the lower end of the rectangular inner frame is provided with an outwardly extending track. Each track extends at a 45° angle in the horizontal direction. The corner molds and L-shaped molds slide on the corresponding tracks. An intermittent driving device is also provided inside the rectangular inner frame.

[0006] When the rectangular inner mold is demolded, the intermittent driving device first drives the two corner molds to slide inward synchronously, and then drives the two L-shaped molds to slide inward synchronously.

[0007] When the rectangular inner mold is closed, the intermittent driving device first drives the two L-shaped molds to slide outward synchronously, and then drives the two corner molds to slide outward synchronously.

[0008] In some embodiments, a first guide rod is provided on the inner side of the corner mold, a first guide sleeve is provided on the rectangular inner frame for the first guide rod to pass through, a second guide rod is provided on the inner side of the L-shaped mold, and a second guide sleeve is provided on the rectangular inner frame for the second guide rod to pass through.

[0009] In some embodiments, the intermittent drive device includes a drive motor and two sets of transmission devices. The corner molds and L-shaped molds on the same left and right sides are divided into one group. The drive motor is located at the center of the rectangular inner frame. One end of each of the two sets of transmission devices is connected to the corner molds and L-shaped molds of the two groups respectively, and the other end is connected to the drive motor. The transmission devices can drive the corner molds and L-shaped molds to slide sequentially.

[0010] In some embodiments, the transmission device includes a first rack disposed on one side of the first guide rod, a first groove for sliding the first rack being opened on one side of the first guide sleeve, a second rack disposed on one side of the second guide rod, a second groove for sliding the second rack being opened on one side of the second guide sleeve, a vertical rotating shaft rotatably disposed on the rectangular inner frame, a first incomplete gear, a second incomplete gear and a first transmission wheel being disposed on the vertical rotating shaft, the first incomplete gear meshing with the first rack, the second incomplete gear meshing with the second rack, a second transmission wheel being disposed on the output shaft of the drive motor, and a transmission belt being sleeved between the first transmission wheel and the second transmission wheel.

[0011] In some embodiments, a first housing is provided at the upper end of the first guide sleeve, a first sliding plate is slidably arranged up and down inside the first housing, a first positioning steel ball is provided at the lower end of the first sliding plate, a first spring is provided at the upper end, and a first positioning groove is spaced along the length direction at the upper end of the first guide rod, and the first positioning steel ball abuts against the first positioning groove under the action of the first spring.

[0012] In some embodiments, a second housing is provided at the upper end of the second guide sleeve, a second sliding plate is slidably arranged inside the second housing, a second positioning steel ball is provided at the lower end of the second sliding plate, a second spring is provided at the upper end, and a second positioning groove is spaced along the length direction at the upper end of the second guide rod, and the second positioning steel ball abuts against the second positioning groove under the action of the second spring.

[0013] In some embodiments, the two side walls of the corner mold and the L-shaped mold that are fitted together are parallel to the extension direction of the corresponding track and form a first fitting surface. The two side walls of the L-shaped mold and the corner mold that are fitted together are a second fitting surface. The outer end of the first fitting surface is provided with a notch. The second fitting surface is provided with a boss that matches the notch. A sealing strip is also provided on the inner side of the boss.

[0014] In some embodiments, rollers that roll on the track are provided at the lower ends of both the angle mold and the L-shaped mold.

[0015] In some embodiments, vertically arranged hydraulic cylinders and vertically slidable vertical guide rods are provided at both ends of the inner side of the L-shaped mold. Connecting plates are spaced vertically on one side of the vertical guide rods. The piston rod of the hydraulic cylinder is fixedly connected to one of the connecting plates. Locking pin ear plates are provided at both ends of the inner side of the corner mold. Locking pin ear plates are provided with locking holes. Locking pins that can be inserted into the locking holes are provided on both connecting plates.

[0016] The present invention also provides a method for demolding a topless rectangular concrete inner mold, using the above-mentioned topless rectangular concrete inner mold demolding device, comprising the following steps:

[0017] Step 1: Demolding preparation. After confirming that the rectangular concrete body has reached the preset demolding strength, start the hydraulic cylinder inside the L-shaped mold. The piston rod of the hydraulic cylinder retracts and drives the connecting plate and locking pin to move synchronously, so that the locking pin exits from the locking hole on the locking pin ear plate of the corner mold, releasing the lock between the corner mold and the L-shaped mold.

[0018] Step 2: Demolding of the corner mold. Start the drive motor of the intermittent drive device. The drive motor drives the first drive wheel on the vertical rotating shaft to rotate through the second transmission wheel and the transmission belt, thereby causing the first incomplete gear on the vertical rotating shaft to rotate synchronously. The first incomplete gear meshes with the first rack on the first guide rod of the corner mold, driving the two corner molds to slide synchronously inward along the track at the lower end of the rectangular inner frame. During the sliding process, the first guide rod moves along the first guide sleeve. After the corner mold is completely separated from the inner wall of the concrete body, the first positioning steel ball abuts against the first positioning groove under the action of the first spring, realizing the positioning of the first guide rod and the corner mold.

[0019] Step 3: Demolding of the L-shaped mold. After the corner mold is demolded, the vertical shaft continues to rotate. At this time, the first incomplete gear disengages from the first rack, while the second incomplete gear meshes with the second rack on the second guide rod of the L-shaped mold, driving the two L-shaped molds to slide inward synchronously along their corresponding tracks. During the sliding process, the second guide rod moves along the second guide sleeve. After the L-shaped mold is completely separated from the inner wall of the concrete body, the second positioning steel ball abuts against the second positioning groove under the action of the second spring, realizing the positioning of the second guide rod and the L-shaped mold, and completing the overall demolding.

[0020] 1. This device, through its innovative structural design, divides the rectangular inner mold into two corner molds and two L-shaped molds, along with tracks extending at a specific angle (45° horizontally) and an intermittent drive mechanism. During demolding, the intermittent drive mechanism first precisely drives the two corner molds to slide inward synchronously, effectively reducing the contact area and friction between the inner mold and the concrete. Then, it drives the two L-shaped molds to slide inward synchronously, completing the entire demolding process. Compared to traditional demolding methods, this significantly improves demolding efficiency and reduces demolding time.

[0021] 2. This gradual demolding method avoids direct hammering and violent disassembly of the mold and concrete, effectively reducing the risk of damage to the inner mold and concrete. It not only ensures the surface integrity and internal structural strength of the concrete, but also extends the service life of the inner mold and reduces production costs.

[0022] 3. There is no need to equip the corner mold and L-shaped mold with separate drive devices, which saves the space occupied by the device and facilitates installation and operation in a confined construction environment. In addition, the same intermittent drive device drives the corner mold and L-shaped mold, which can strictly control the action sequence and time interval of the two, ensuring that the corner mold completes the movement before the L-shaped mold starts. This avoids action conflicts or coordination errors caused by poor synchronization of multiple drive devices, and improves the stability and reliability of the demolding and mold closing process. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the three-dimensional structure of the inner mold after it is closed according to the present invention.

[0024] Figure 2 This is a schematic diagram of the main structure of the inner mold after it is closed according to the present invention.

[0025] Figure 3 This is a top view of the structure of the inner mold after it is closed according to the present invention.

[0026] Figure 4 This is a top view of the structure of the present invention when the corner mold moves inward to demold.

[0027] Figure 5 For the present invention Figure 1 Enlarged diagram of point A.

[0028] Figure 6 For the present invention Figure 3 Enlarged diagram of point B.

[0029] Figure 7 This is a schematic diagram of the structure of the inner mold and the L-shaped mold of the present invention.

[0030] Figure 8 This is a schematic diagram of the rectangular inner frame of the present invention.

[0031] Figure 9 This is a partial structural schematic diagram of the gap driving device of the present invention.

[0032] Figure 10 This is one of the partial structural schematic diagrams of the present invention.

[0033] Figure 11 This is a second partial structural schematic diagram of the present invention. Detailed Implementation

[0034] The following detailed description provides various embodiments or examples for carrying out the present invention. Of course, these are merely embodiments or examples and are not intended to be limiting. Additionally, repeated reference numerals, such as repeated numbers and / or letters, may be used in different embodiments. These repetitions are for the purpose of simple and clear description of the invention and do not represent a specific relationship between the different embodiments and / or structures discussed.

[0035] like Figures 1-11 The device shown is a topless rectangular concrete inner mold demolding device, which includes a rectangular inner mold 1. The rectangular inner mold 1 is divided into four templates, including two corner molds 2 and two L-shaped molds 3. The two corner molds 2 and the two L-shaped molds 3 are arranged alternately around each other. A rectangular inner frame 4 is arranged inside the rectangular inner mold 1. The four corners of the lower end of the rectangular inner frame 4 are provided with outwardly extending tracks 5. Each track 5 extends at 45° in the horizontal direction. The corner molds 2 and L-shaped molds 3 slide on the tracks 5 respectively. An intermittent driving device is also provided inside the rectangular inner frame 4.

[0036] When the rectangular inner mold 1 is demolded, the intermittent driving device first drives the two corner molds 2 to slide inward synchronously, and then drives the two L-shaped molds 3 to slide inward synchronously.

[0037] When the rectangular inner mold 1 is closed, the intermittent driving device first drives the two L-shaped molds 3 to slide outward synchronously, and then drives the two corner molds 2 to slide outward synchronously.

[0038] This device, through its innovative structural design, divides the rectangular inner mold 1 into two corner molds 2 and two L-shaped molds 3, and is equipped with a track 5 extending at a specific angle (45° horizontally) and an intermittent drive device. During demolding, the intermittent drive device first precisely drives the two corner molds 2 to slide inward synchronously, effectively reducing the contact area and friction between the inner mold and the concrete. Then, it drives the two L-shaped molds 3 to slide inward synchronously, completing the entire demolding process. Compared with traditional demolding methods, this significantly improves demolding efficiency and reduces demolding time.

[0039] This gradual demolding method avoids direct hammering and violent disassembly of the mold and concrete, effectively reducing the risk of damage to the inner mold and concrete. It ensures the surface integrity and internal structural strength of the concrete, extends the service life of the inner mold, and reduces production costs.

[0040] Moreover, there is no need to equip corner mold 2 and L-shaped mold 3 with separate drive devices, saving space and making it easier to install and operate in confined construction environments. In addition, the same intermittent drive device drives corner mold 2 and L-shaped mold 3, which can strictly control the sequence and time interval of their actions, ensuring that corner mold 2 completes its movement before L-shaped mold 3 starts, avoiding action conflicts or coordination errors caused by poor synchronization of multiple drive devices, and improving the stability and reliability of the demolding and mold closing process.

[0041] See Figure 3 , Figure 4 , Figure 7 , Figure 8 As shown, a first guide rod 21 is provided on the inner side of the corner mold 2, a first guide sleeve 22 is provided on the rectangular inner frame 4 for the first guide rod 21 to pass through, a second guide rod 23 is provided on the inner side of the L-shaped mold 3, and a second guide sleeve 24 is provided on the rectangular inner frame 4 for the second guide rod 23 to pass through.

[0042] The cooperation between the first guide rod 21 and the first guide sleeve 22, and the second guide rod 23 and the second guide sleeve 24, provides precise guidance for the sliding of the corner mold 2 and the L-shaped mold 3, ensuring the straightness and stability of the template sliding, avoiding problems such as offset and jamming during the sliding process, and ensuring the smooth progress of the demolding and mold closing process.

[0043] The intermittent drive device includes a drive motor 30 and two sets of transmission devices. The corner mold 2 and L-shaped mold 3 on the same side are divided into one group. The drive motor 30 is located at the center of the rectangular inner frame 4. One end of each of the two sets of transmission devices is connected to the corner mold 2 and L-shaped mold 3 of the two groups respectively, and the other end is connected to the drive motor 30. The transmission devices can drive the corner mold 2 and L-shaped mold 3 to slide sequentially.

[0044] Therefore, during the demolding process, the transmission device, driven by the drive motor 30, first drives the corner mold 2 to slide, and then drives the L-shaped mold 3 to slide; similarly, during the mold closing process, the drive motor 30 rotates in the opposite direction, first driving the L-shaped mold 3 to slide, and then driving the corner mold 2 to slide.

[0045] Furthermore, a drive motor 30, in conjunction with two sets of transmission devices, is used to drive the two sets of corner molds 2 and L-shaped molds 3, simplifying the device structure and reducing costs. Simultaneously, the transmission devices ensure that the corner molds 2 and L-shaped molds 3 slide sequentially in a preset order, guaranteeing the coordination and accuracy of demolding and mold closing actions.

[0046] See Figure 3 , Figure 4 , Figure 8 , Figure 9As shown, the transmission device includes a first rack 31 disposed on one side of the first guide rod 21, a first groove 32 for sliding the first rack 31 is provided on one side of the first guide sleeve 22, a second rack 33 is disposed on one side of the second guide rod 23, a second groove 34 for sliding the second rack 33 is provided on one side of the second guide sleeve 24, a vertical rotating shaft 35 is rotatably disposed on the rectangular inner frame 4, a first incomplete gear 36, a second incomplete gear 37 and a first transmission wheel 38 are respectively disposed on the vertical rotating shaft 35, the first incomplete gear 36 meshes with the first rack 31, the second incomplete gear 37 meshes with the second rack 33, a second transmission wheel 39 is disposed on the output shaft of the drive motor 30, and a transmission belt 310 is connected and sleeved between the first transmission wheel 38 and the second transmission wheel 39.

[0047] When the drive motor 30 is working, it drives the vertical rotating shaft 35 to rotate through the transmission belt 310. The first incomplete gear 36 first meshes with the first rack 31 to drive the angle mold 2 to slide, and then the second incomplete gear 37 meshes with the second rack 33 to drive the L-shaped mold 3 to slide.

[0048] It should be noted that when the first incomplete gear 36 meshes with the first rack 31, the second incomplete gear 37 disengages from the second rack 33, and when the second incomplete gear 37 meshes with the second rack 33, the first incomplete gear 36 disengages from the first rack 31.

[0049] By utilizing the meshing transmission of incomplete gears and racks, the sequential operation of angle mold 2 and L-shaped mold 3 is precisely achieved, resulting in reliable and highly efficient transmission. The belt drive system is simple in structure, low in cost, and capable of long-distance transmission, adapting well to the structural layout of the device. The overall transmission system ensures the stability of power transmission and the sequential nature of actions.

[0050] See Figure 8 , Figure 10 As shown, a first housing 51 is provided at the upper end of the first guide sleeve 22, a first sliding plate 52 is slidably mounted inside the first housing 51, a first positioning steel ball 53 is provided at the lower end of the first sliding plate 52, a first spring 54 is provided at the upper end, and a first positioning groove 55 is spaced along the length of the upper end of the first guide rod 21. The first positioning steel ball 53 abuts against the first positioning groove 55 under the action of the first spring 54.

[0051] The first positioning steel ball 53 and the first positioning groove 55 work together to accurately position the sliding position of the corner mold 2, ensuring that the corner mold 2 can be stably maintained in this position after demolding or mold closing, avoiding slippage or displacement, and improving the reliability of the device. At the same time, the positioning method is simple and does not affect the normal sliding of the guide rod.

[0052] See Figure 8 , Figure 11 As shown, a second housing 61 is provided at the upper end of the second guide sleeve 24, a second sliding plate 62 slides up and down inside the second housing 61, a second positioning steel ball 63 is provided at the lower end of the second sliding plate 62, a second spring 64 is provided at the upper end, and a second positioning groove 65 is spaced along the length direction at the upper end of the second guide rod 23. The second positioning steel ball 63 abuts against the second positioning groove 65 under the action of the second spring 64.

[0053] The positioning structure of L-shaped mold 3 is the same as that of corner mold 2, which accurately positions the sliding position of L-shaped mold 3, ensuring that L-shaped mold 3 remains stable after it is in place, further improving the reliability of the device and ensuring the accuracy of the demolding and mold closing process.

[0054] It should be noted that when the first incomplete gear 36 disengages from the first rack 31, the first positioning steel ball 53 abuts against the first positioning groove 55, thereby positioning the diagonal mold 2; while when the second incomplete gear 37 disengages from the second rack 33, the second positioning steel ball 63 abuts against the second positioning groove 65, thereby positioning the L-shaped mold 3.

[0055] See Figure 3 , Figure 4 , Figure 6 , Figure 7 As shown, the two side walls of the corner mold 2 and the L-shaped mold 3 that are attached to each other are parallel to the extension direction of the corresponding track 5 and form a first fitting surface 71. The two side walls of the L-shaped mold 3 and the corner mold 2 that are attached to each other are a second fitting surface 72. The outer end of the first fitting surface 71 is provided with a notch 73. The second fitting surface 72 is provided with a boss 74 that is adapted to the notch 73. A sealing strip 75 is also provided on the inner side of the boss 74.

[0056] When the corner mold 2 and the L-shaped mold 3 are closed, the boss 74 is embedded in the notch 73, and the sealing strip 75 is squeezed to achieve a seal.

[0057] The fit between the notch 73 and the boss 74 enhances the tightness of the fit between the corner mold 2 and the L-shaped mold 3. The sealing strip 75 further improves the sealing performance, effectively reduces the leakage of grout during the concrete pouring process, ensures the molding quality of the concrete body, and makes the internal structure of the concrete body more compact.

[0058] In addition, a first guide slope 76 is provided at both ends of the inner side of the corner mold 2, and a second guide slope 77 is provided at both ends of the inner side of the L-shaped mold 3. Thus, the template plays a certain guiding role when the mold is closed, preventing the template from colliding.

[0059] In this invention, rollers 91 that roll on the track 5 are provided at the lower ends of both the corner mold 2 and the L-shaped mold 3, making the template slide more smoothly and effortlessly, reducing the load on the drive device, extending the service life of the device, and also improving the efficiency of demolding and mold closing.

[0060] See Figure 1 , Figure 5 As shown, vertically arranged hydraulic cylinders 10 and vertically sliding guide rods 11 are provided at both ends of the inner side of the L-shaped mold 3. Connecting plates 12 are spaced vertically on one side of the vertical guide rods 11. The piston rod of the hydraulic cylinder 10 is fixedly connected to one of the connecting plates 12. Locking pin ear plates 13 are provided at both ends of the inner side of the corner mold 2. Locking pin ear plates 13 are provided with locking holes 14. Locking pins 15 that can be inserted into the locking holes 14 are provided on both connecting plates 12.

[0061] After the corner mold 2 and the L-shaped mold 3 are closed, the hydraulic cylinder 10 drives the connecting plate 12 to drive the locking pin 15 to insert into the locking hole 14, thereby locking the corner mold 2 and the L-shaped mold 3; before demolding, the hydraulic cylinder 10 drives the locking pin 15 to exit the locking hole 14 to release the lock.

[0062] The locking and unlocking of the corner mold 2 and L-shaped mold 3 are achieved by driving the locking pin 15 through the hydraulic cylinder 10. The operation is convenient and the locking is firm. When the mold is closed, it can ensure the overall stability of the inner mold under the pressure of concrete pouring, and prevent the template from shifting or deforming. When demolding, it can quickly release the lock without affecting the normal sliding of the template, which improves the safety and reliability of the device.

[0063] The present invention also provides a method for demolding a topless rectangular concrete inner mold, using the above-mentioned topless rectangular concrete inner mold demolding device, comprising the following steps:

[0064] Step 1: Demolding preparation. After confirming that the rectangular concrete body has reached the preset demolding strength, start the hydraulic cylinder 10 inside the L-shaped mold 3. The piston rod of the hydraulic cylinder 10 retracts and drives the connecting plate 12 and the locking pin 15 to move synchronously, so that the locking pin 15 exits from the locking hole 14 on the locking pin ear plate 13 of the corner mold 2, thereby releasing the lock between the corner mold 2 and the L-shaped mold 3.

[0065] Step 2: Demolding of the corner mold. Start the drive motor 30 of the intermittent drive device. The drive motor 30 drives the first drive wheel 38 on the vertical rotating shaft 35 to rotate through the second transmission wheel 39 and the transmission belt 310. This causes the first incomplete gear 36 on the vertical rotating shaft 35 to rotate synchronously. The first incomplete gear 36 meshes with the first rack 31 on the first guide rod 21 of the corner mold 2, driving the two corner molds 2 to slide synchronously inward along the track 5 at the lower end of the rectangular inner frame 4. During the sliding process, the first guide rod 21 moves along the first guide sleeve 22. After the corner mold 2 is completely separated from the inner wall of the concrete body, the first positioning steel ball 53 abuts against the first positioning groove 55 under the action of the first spring 54, realizing the positioning of the first guide rod 21 and the corner mold 2.

[0066] Step 3: Demolding of L-shaped mold. After the corner mold 2 is demolded, the vertical rotating shaft 35 continues to rotate. At this time, the first incomplete gear 36 disengages from the first rack 31, while the second incomplete gear 37 meshes with the second rack 33 on the second guide rod 23 of the L-shaped mold 3, driving the two L-shaped molds 3 to slide inward synchronously along the corresponding track 5. During the sliding process, the second guide rod 23 moves along the second guide sleeve 24. After the L-shaped mold 3 is completely separated from the inner wall of the concrete body, the second positioning steel ball 63 abuts against the second positioning groove 65 under the action of the second spring 64, realizing the positioning of the second guide rod 23 and the L-shaped mold 3, and completing the overall demolding.

[0067] This demolding method features clear steps and standardized operation. It involves first unlocking the concrete before demolding in stages, ensuring a smooth and safe process. Through the coordinated work of all components, efficient, precise, and safe demolding is achieved, preventing damage to the concrete and inner mold, and improving construction quality and efficiency.

[0068] Based on the accompanying drawings and the foregoing illustrations and descriptions, the basic principles and main features of the present invention, as well as its advantages, those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A demolding device for a rectangular concrete inner mold without a top cover, comprising a rectangular inner mold (1), characterized in that: The rectangular inner mold (1) is divided into four templates, including two corner molds (2) and two L-shaped molds (3). The two corner molds (2) and the two L-shaped molds (3) are arranged in a row and spaced apart. A rectangular inner frame (4) is provided in the rectangular inner mold (1). The four corners of the lower end of the rectangular inner frame (4) are provided with outward extending tracks (5). Each track (5) extends at 45° in the horizontal direction. The corner molds (2) and L-shaped molds (3) slide on each track (5) respectively. An intermittent drive device is also provided in the rectangular inner frame (4). When the rectangular inner mold (1) is demolded, the two corner molds (2) are first driven to slide inward synchronously by the intermittent driving device, and then the two L-shaped molds (3) are driven to slide inward synchronously. When the rectangular inner mold (1) is closed, the intermittent driving device first drives the two L-shaped molds (3) to slide outward synchronously, and then drives the two corner molds (2) to slide outward synchronously. A first guide rod (21) is provided on the inner side of the corner mold (2), and a first guide sleeve (22) is provided on the rectangular inner frame (4) for the first guide rod (21) to pass through. A second guide rod (23) is provided on the inner side of the L-shaped mold (3), and a second guide sleeve (24) is provided on the rectangular inner frame (4) for the second guide rod (23) to pass through. The intermittent driving device includes a drive motor (30) and two sets of transmission devices. The corner mold (2) and L-shaped mold (3) on the same side are divided into one group. The drive motor (30) is located at the center of the rectangular inner frame (4). One end of each set of transmission devices is connected to the corner mold (2) and L-shaped mold (3) of the two groups respectively, and the other end is connected to the drive motor (30). The transmission device can drive the corner mold (2) and L-shaped mold (3) to slide sequentially. The transmission device includes a first rack (3) provided on one side of the first guide rod (21). 1) A first groove (32) for sliding the first rack (31) is provided on one side of the first guide sleeve (22), a second rack (33) is provided on one side of the second guide rod (23), a second groove (34) for sliding the second rack (33) is provided on one side of the second guide sleeve (24), a vertical shaft (35) is rotatably provided on the rectangular inner frame (4), a first incomplete gear (36), a second incomplete gear (37) and a first transmission wheel (38) are respectively provided on the vertical shaft (35), the first incomplete gear (36) meshes with the first rack (31), the second incomplete gear (37) meshes with the second rack (33), a second transmission wheel (39) is provided on the output shaft of the drive motor (30), and a transmission belt (310) is connected and sleeved between the first transmission wheel (38) and the second transmission wheel (39).

2. The demolding device for a topless rectangular concrete inner mold according to claim 1, characterized in that: A first housing (51) is provided at the upper end of the first guide sleeve (22). A first sliding plate (52) slides up and down inside the first housing (51). A first positioning steel ball (53) is provided at the lower end of the first sliding plate (52). A first spring (54) is provided at the upper end. A first positioning groove (55) is spaced along the length direction at the upper end of the first guide rod (21). The first positioning steel ball (53) abuts against the first positioning groove (55) under the action of the first spring (54).

3. The topless rectangular concrete inner mold demolding device according to claim 2, characterized in that: A second housing (61) is provided at the upper end of the second guide sleeve (24). A second sliding plate (62) slides up and down inside the second housing (61). A second positioning steel ball (63) is provided at the lower end of the second sliding plate (62), and a second spring (64) is provided at the upper end. A second positioning groove (65) is spaced along the length direction at the upper end of the second guide rod (23). The second positioning steel ball (63) abuts against the second positioning groove (65) under the action of the second spring (64).

4. The topless rectangular concrete inner mold demolding device according to claim 1, characterized in that: The two side walls of the corner mold (2) and the L-shaped mold (3) are parallel to the extension direction of the corresponding track (5) and form a first mating surface (71). The two side walls of the L-shaped mold (3) and the corner mold (2) are a second mating surface (72). The outer end of the first mating surface (71) is provided with a notch (73). The second mating surface (72) is provided with a boss (74) that matches the notch (73). A sealing strip (75) is also provided on the inner side of the boss (74).

5. The demolding device for a topless rectangular concrete inner mold according to claim 1, characterized in that: Rollers (91) that roll on the track (5) are provided at the lower ends of both the corner mold (2) and the L-shaped mold (3).

6. The demolding device for a topless rectangular concrete inner mold according to claim 3, characterized in that: At both ends of the inner side of the L-shaped mold (3), there are vertically arranged oil cylinders (10) and vertically sliding guide rods (11). There are connecting plates (12) spaced vertically on one side of the vertical guide rods (11). The piston rod of the oil cylinder (10) is fixedly connected to one of the connecting plates (12). At both ends of the inner side of the corner mold (2), there are locking pin ear plates (13). The locking pin ear plates (13) are provided with locking holes (14). On both connecting plates (12), there are locking pins (15) that can be inserted into the locking holes (14).

7. A method for demolding a topless rectangular concrete inner formwork, characterized in that: The demolding device for the topless rectangular concrete inner mold of claim 6 includes the following steps: Step 1: Demolding preparation. After confirming that the rectangular concrete body has reached the preset demolding strength, start the oil cylinder (10) inside the L-shaped mold (3). The piston rod of the oil cylinder (10) retracts and drives the connecting plate (12) and the locking pin (15) to move synchronously, so that the locking pin (15) exits from the locking hole (14) on the locking pin ear plate (13) of the corner mold (2), and releases the locking between the corner mold (2) and the L-shaped mold (3). Step 2: Demolding of the corner mold, start the drive motor (30) of the intermittent drive device. The drive motor (30) drives the first drive wheel (38) on the vertical shaft (35) to rotate through the second drive wheel (39) and the drive belt (310), thereby causing the first incomplete gear (36) on the vertical shaft (35) to rotate synchronously. The first incomplete gear (36) meshes with the first rack (31) on the first guide rod (21) of the corner mold (2), driving the two corner molds (2) to slide synchronously inward along the track (5) at the lower end of the rectangular inner frame (4). During the sliding process, the first guide rod (21) moves along the first guide sleeve (22). After the corner mold (2) is completely separated from the inner wall of the concrete body, the first positioning steel ball (53) abuts against the first positioning groove (55) under the action of the first spring (54), realizing the positioning of the first guide rod (21) and the corner mold (2). Step 3: Demolding of L-shaped mold. After the corner mold (2) is demolded, the vertical rotating shaft (35) continues to rotate. At this time, the first incomplete gear (36) disengages from the first rack (31), while the second incomplete gear (37) meshes with the second rack (33) on the second guide rod (23) of the L-shaped mold (3), driving the two L-shaped molds (3) to slide inward synchronously along the corresponding track (5). During the sliding process, the second guide rod (23) moves along the second guide sleeve (24). After the L-shaped mold (3) is completely separated from the inner wall of the concrete body, the second positioning steel ball (63) abuts against the second positioning groove (65) under the action of the second spring (64), realizing the positioning of the second guide rod (23) and the L-shaped mold (3), and completing the overall demolding.

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