Orthopedic brace for spinal fracture
By designing a spinal fracture orthotic brace with compression tightening and unlocking components, and utilizing a ratchet module and winch structure, the problem of secondary injury caused by uneven pressure and the difficulty of autonomous wearing in existing technologies have been solved, enabling fast and safe operation of the spinal fracture orthotic brace.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHANGZHOU HUANUO MEDICAL TECHNOLOGY CO LTD
- Filing Date
- 2026-03-10
- Publication Date
- 2026-05-12
AI Technical Summary
Existing spinal fracture orthotic braces suffer from secondary injuries due to uneven pressure during the binding process, and patients find it difficult to wear and operate them independently.
An orthopedic brace for spinal fractures, comprising a compression tightening component and a compression unlocking component, was designed. It utilizes a ratchet module and a winch structure to achieve rapid tightening and unlocking. The rope is wound and unwound by a compression ball and a gas-driven piston disc. Combined with the unidirectional rotational characteristics of the ratchet module, it ensures uniform clamping and autonomous operation.
It enables patients to tighten and loosen the pressure quickly and independently, avoiding secondary injuries caused by uneven pressure and improving the convenience and safety of use.
Smart Images

Figure CN122005175A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of medical device technology, specifically an orthotic brace for spinal fractures. Background Technology
[0002] In cases of accidental injury, the spine is highly susceptible to fractures due to external impact. These injuries often disrupt the physiological stability of the spine, leading to secondary problems such as vertebral displacement and nerve compression. This severely impacts the patient's physical function and rehabilitation process. Clinically, spinal correction surgery is often used to treat this condition. However, the spine's mechanical support capacity is not fully restored post-surgery, necessitating long-term assisted rehabilitation intervention with orthotic braces. Orthotic braces, through their structural design that conforms to the physiological curvature of the human spine, precisely clamp and fix the patient's body, effectively distributing the weight-bearing pressure on the spine, reducing the mechanical burden on the affected vertebrae, preventing abnormal spinal movement after surgery, and creating a stable mechanical environment for callus growth at the fracture site. This, in turn, accelerates the patient's rehabilitation process and improves the quality of post-operative physical function recovery.
[0003] In existing technologies, when fixing a splint, the straps need to be fixed sequentially. During the binding process, one side is usually compressed while the other side is loose, which can cause secondary injuries to the patient due to uneven pressure. In addition, this structure requires the patient to connect the straps to the back or apply tension, which cannot achieve the effect of self-wearing and is inconvenient to operate and use. Summary of the Invention
[0004] To address the problems mentioned in the background art, the present invention provides an orthotic brace for spinal fractures, which solves the problem that existing devices are usually compressed on one side and loose on the other side when being bound, causing secondary injury to the patient due to uneven pressure. At the same time, the structure requires the patient to connect the strap to the back or apply tension, which cannot achieve the effect of self-wearing and is inconvenient to operate and use.
[0005] To achieve the above objectives, the present invention provides the following technical solution: an orthotic brace for spinal fractures, comprising a front splint, wherein a compression tightening component is provided on one side of the front splint; The compression tightening assembly includes a winch, and six sets of connecting ropes are wound around the inner side of the winch. The compression tightening assembly includes a sealing tube, and a movable tube is slidably arranged in the middle of the sealing tube. Piston discs are installed at both ends of the movable tube. The piston discs are slidably arranged inside the movable tube. A telescopic inclined block is telescopically arranged at the lower end of the movable tube. The compression tightening assembly includes a first ratchet module, and several sets of fixed helical teeth are installed on the outer ring of the first ratchet module. A sliding column is installed at the top of the movable tube, and a sliding frame is slidably arranged on the outer side of the sliding column. Two sets of pushing columns are respectively arranged on both sides of the sliding frame, and a bistable buckling beam is arranged on the inner side of the two sets of pushing columns.
[0006] Preferably, a winch box is provided on the outer side of the winch via a bearing, and the winch box is fixedly installed on one side of the front clamping plate. Six sets of guide ends are installed on the outer side of the winch box, and the connecting rope is movably arranged on the inner side of the guide ends. A hook is installed at the end of the connecting rope.
[0007] Preferably, a second ratchet module is assembled on the inner side of the first ratchet module away from the winch box, a drive box is installed on the side of the winch box away from the front clamp, the sealing tube is fixedly installed on the inner side of the upper end of the drive box, guide rods are installed on both sides of the upper end of the drive box, and the movable tube is slidably arranged on the outer side of the guide rods.
[0008] Preferably, the second ratchet module is fixedly installed on one side inside the drive box, an adjustment frame is installed on the top of the drive box, the sliding frame is slidably and reciprocally arranged inside the adjustment frame, and a splicing groove is opened in the middle of the first ratchet module.
[0009] Preferably, a telescopic cylinder is installed in the middle of the movable tube, a compression block is installed on the top of the telescopic inclined block, and the compression block is slidably disposed inside the telescopic cylinder. The top of the compression block and the telescopic cylinder are elastically connected by a compression spring, and one-way valves are provided at both ends of the sealing tube.
[0010] Preferably, a squeeze unlocking component is provided in the middle of the winch; The squeeze unlocking component includes a fixed frame, and a telescopic frame is telescopically provided on the inner side of the fixed frame. The telescopic frame is slidably spliced on the inner side of the splicing groove. A limit ring is installed on one end of the telescopic frame near the fixed frame, and the limit ring is slidably disposed on the inner side of the fixed frame.
[0011] Preferably, the telescopic frame and the fixed frame are elastically connected by a return spring, a pressing column is installed at the end of the telescopic frame away from the fixed frame, and a rotating disk is installed at the end of the pressing column away from the fixed frame. The rotating disk and the drive box are elastically connected by a flexible sheet.
[0012] Preferably, a switching valve is installed on the upper end of the drive box near the winch box, and an air inlet hose is installed on the top of the switching valve. A pressure ball is installed on the end of the air inlet hose away from the switching valve. Exhaust hoses are installed on both sides of the switching valve, and the end of the exhaust hose away from the switching valve is fixedly connected to both ends of the sealing pipe.
[0013] Preferably, the bottom of the switching valve is provided with a valve lever, which is movably located in the middle of one side of the sliding frame. The two ends of the bistable buckling beam are equipped with fixing rods, which are fixedly installed on the top of the drive box.
[0014] Preferably, the upper end of the front clamp is provided with two sets of shoulder straps, and the end of the shoulder straps is provided with a rear clamp. Three sets of tightening waist belts are respectively installed on both sides of the rear clamp. The hook assembly is located at the end of the tightening waist belt. Several sets of heat dissipation holes are opened on the inner side of the front clamp and the rear clamp.
[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention utilizes a combination of a compression tightening component and a tightening belt to achieve rapid tightening through compression in conjunction with a ratchet module. By compressing the pressure ball, air inside is introduced through the intake hose to the switching valve and then through the exhaust hose to the sealed tube. During this process, the compression piston disc and the movable tube slide laterally. During adjustment, the vertical surface of the telescopic inclined block abuts against the plane of the fixed inclined tooth block, pushing the first ratchet module to rotate along the second ratchet module. This rotation simultaneously drives the winch to rotate via the telescopic frame and the fixed frame, winding up the connecting rope. Pulling the connecting rope simultaneously rotates the hook at the end, controlling the tightening belt to tighten the front and rear clamps. This tightening process simultaneously clamps the patient's torso, effectively preventing strain caused by tightening on one side. Furthermore, the patient can use it independently, facilitating operation and reducing the risk of secondary injury from excessive force exerted by staff.
[0016] This invention utilizes a combination of a squeeze-to-unlock component and a squeeze-to-tighten component to facilitate rapid unlocking via pressing. During the pressing process, the squeeze column drives the telescopic frame into the interior of the fixed frame, compressing the internal reset spring. Once the telescopic frame separates from the splicing groove of the first ratchet module, the tension generated by the original tightening will cause the winch to automatically rotate in the opposite direction. After rotation, the connecting rope will be simultaneously loosened, avoiding the problem of uneven tension causing injury to the patient due to sequential loosening. At the same time, the patient can unlock quickly and independently, making it easy to operate and use. Attached Figure Description
[0017] Figure 1This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the cross-sectional structure of the winch assembly of the present invention; Figure 3 This is a schematic cross-sectional view of the extrusion tightening component of the present invention; Figure 4 For the present invention Figure 3 Enlarged structural diagram at point B; Figure 5 This is a schematic diagram of the cross-sectional structure of the adjustment frame of the present invention; Figure 6 For the present invention Figure 2 Enlarged structural diagram at point A in the middle; Figure 7 This is a schematic diagram of the combined cross-sectional structure of the present invention.
[0018] In the diagram: 100, front brace; 101, shoulder strap; 102, rear brace; 103, ventilation holes; 104, waist belt; 001. Extrusion tightening assembly; 200. Winch; 201. Winch box; 202. Guide end; 203. Connecting rope; 204. Hook; 002. Compression unlocking assembly; 300. Flexible sheet; 301. Fixed frame; 302. Telescopic frame; 303. Limiting ring; 304. Return spring; 305. Compression column; 306. Rotary disk; 400. Fixed helical tooth block; 401. Drive box; 402. First ratchet module; 403. Second ratchet module; 404. Splicing groove; 405. Adjustment frame; 406. Guide rod; 500. Telescopic inclined block; 501. Sealing tube; 502. Telescopic cylinder; 503. Movable tube; 504. Piston disc; 505. Compression spring; 506. Compression block; 507. Sliding column; 508. One-way valve; 600. Bistable buckling beam; 601. Switching valve; 602. Inlet hose; 603. Exhaust hose; 604. Valve lever; 605. Sliding frame; 606. Push column; 607. Fixing rod; 608. Pressure ball. Detailed Implementation
[0019] 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.
[0020] like Figures 1 to 7As shown, the present invention provides an orthotic brace for spinal fractures, including a front splint 100, and a compression tightening assembly 001 is provided on one side of the front splint 100; The compression tightening assembly 001 includes a winch 200, and six sets of connecting ropes 203 are wound around the inner side of the winch 200. The compression tightening assembly 001 includes a sealing tube 501, and a movable tube 503 is slidably arranged in the middle of the sealing tube 501. Piston discs 504 are installed at both ends of the movable tube 503. The piston discs 504 are slidably arranged inside the movable tube 503. A telescopic inclined block 500 is telescopically arranged at the lower end of the movable tube 503. The compression tightening assembly 001 includes a first ratchet module 402, and several sets of fixed helical teeth 400 are installed on the outer ring of the first ratchet module 402. A sliding column 507 is installed on the top of the movable tube 503, and a sliding frame 605 is slidably arranged on the outer side of the sliding column 507. Two sets of push columns 606 are respectively arranged on both sides of the sliding frame 605, and a bistable buckling beam 600 is arranged inside the two sets of push columns 606.
[0021] Using the above scheme: the front clamping plate 100 and the rear clamping plate 102 can clamp the torso; the winch 200 can wind up the connecting rope 203 wound inside by rotating; adjusting the winding can pull the hook 204 at the end to achieve a synchronous tightening effect; the sealing tube 501 can maintain the sealed cavity at both ends; the piston disc 504 is slidably set inside, and when gas fills the interior, it will push the piston disc 504 to slide laterally; the movable tube 503 can connect the two sets of piston discs 504; the telescopic inclined block 500 can squeeze and fix the helical tooth block 400 for movement adjustment when pushed laterally; the first ratchet module 402 and the second ratchet module 402... The wheel module 403 is a ratchet module structure, which enables rotation in only one direction. The sliding column 507 performs lateral reciprocating sliding adjustment under the synchronous movement of the movable tube 503. The inner side of the sliding frame 605 is a cavity structure. The sliding column 507 can only squeeze the two ends of the sliding frame 605, thereby driving the sliding frame 605 to perform lateral sliding adjustment. The pushing column 606 can clamp the bistable buckling beam 600. When the pressure exceeds the threshold, the bistable buckling beam 600 will quickly deform and move to the other side, thereby realizing a switch-like structure. By moving quickly, the valve lever 604 is driven to swing, thereby achieving the effect of valve flow switching.
[0022] like Figure 2 - Figure 4 As shown, a winch box 201 is provided on the outer side of the winch 200 via a bearing, and the winch box 201 is fixedly installed on one side of the front clamp 100, so that six sets of guide ends 202 are installed on the outer side of the winch box 201, and the connecting rope 203 is movably arranged on the inner side of the guide ends 202, and a hook 204 is installed at the end of the connecting rope 203.
[0023] The second ratchet module 403 is assembled on the inner side of the first ratchet module 402 away from the winch box 201. The drive box 401 is installed on the side of the winch box 201 away from the front clamping plate 100. The sealing tube 501 is fixedly installed on the inner side of the upper end of the drive box 401. Guide rods 406 are installed on both sides of the upper end of the drive box 401. The movable tube 503 is slidably arranged on the outer side of the guide rods 406.
[0024] The second ratchet module 403 is fixedly installed on one side inside the drive box 401. An adjustment frame 405 is installed on the top of the drive box 401. A sliding frame 605 is slidably and reciprocally arranged inside the adjustment frame 405. A splicing groove 404 is opened in the middle of the first ratchet module 402.
[0025] A telescopic cylinder 502 is installed in the middle of the movable tube 503, and a pressing block 506 is installed on the top of the telescopic inclined block 500. The pressing block 506 is slidably disposed inside the telescopic cylinder 502. The top of the pressing block 506 and the telescopic cylinder 502 are elastically connected by a pressing spring 505. One-way valves 508 are provided at both ends of the sealing tube 501.
[0026] Using the above scheme: the winch box 201 can provide an installation position for the internal structure, the guide end 202 can guide the connecting rope 203, ensuring that the connecting rope 203 can be connected to the hook 204 at the end, and the hook 204 can be connected to the tightening belt 104. After connection, the pulling effect can be achieved. The drive box 401 can provide a constraint for the internal structure, the guide rod 406 can guide the movable tube 503, ensuring the stability of the lateral movement of the movable tube 503, the adjustment frame 405 can constrain the internal structure, and the splicing groove 404 can be spliced with the telescopic frame 302. After splicing, the kinetic energy transmission effect can be achieved.
[0027] like Figure 3 and Figure 6 As shown, a squeeze unlocking component 002 is provided in the middle of the winch 200; The squeeze unlocking component 002 includes a fixed frame 301, and a telescopic frame 302 is telescopically provided on the inner side of the fixed frame 301. The telescopic frame 302 is slidably spliced on the inner side of the splicing groove 404. A limit ring 303 is installed on one end of the telescopic frame 302 near the fixed frame 301, and the limit ring 303 is slidably disposed on the inner side of the fixed frame 301.
[0028] The telescopic frame 302 and the fixed frame 301 are elastically connected by a reset spring 304. A pressing column 305 is installed at the end of the telescopic frame 302 away from the fixed frame 301, and a rotating disk 306 is installed at the end of the pressing column 305 away from the fixed frame 301. The rotating disk 306 and the drive box 401 are elastically connected by a flexible sheet 300.
[0029] The above scheme is as follows: the fixed frame 301 can restrict the inner structure, the telescopic frame 302 can be telescopically adjusted inside the fixed frame 301, the limiting ring 303 can ensure the stability of the sliding adjustment of the telescopic frame 302, the extrusion column 305 can extrude and adjust the telescopic frame 302, the return spring 304 can push the telescopic frame 302 outward, and after outward, the telescopic frame 302 and the splicing groove 404 can be in a combined state, thereby achieving kinetic energy transfer, the rotating disk 306 can assist in the rotation adjustment, and the flexible sheet 300 can deform to form a closed space to prevent dust from entering the interior.
[0030] like Figure 3 and Figure 6 As shown, a switching valve 601 is installed on the upper end of the drive box 401 near the winch box 201, and an air intake hose 602 is installed on the top of the switching valve 601. A pressure ball 608 is installed at the end of the air intake hose 602 away from the switching valve 601. Exhaust hoses 603 are installed on both sides of the switching valve 601, and the end of the exhaust hose 603 away from the switching valve 601 is fixedly connected to both ends of the sealing pipe 501.
[0031] The bottom of the switching valve 601 is equipped with a valve lever 604, which is movably located in the middle of one side of the sliding frame 605. The two ends of the bistable buckling beam 600 are equipped with fixing rods 607, which are fixedly installed on the top of the drive box 401.
[0032] Using the above scheme: the switching valve 601 can achieve the effect of flow channel switching by rotating the valve lever 604 at the bottom; the air inlet hose 602 and the air outlet hose 603 can transmit gas, and the drive adjustment can be performed through transmission; the pressure ball 608 is an inflation device that can assist the patient in squeezing and inflating; and the fixing rod 607 can restrict the bistable buckling beam 600 to ensure the stability of the structure.
[0033] like Figure 1 As shown, the upper end of the front plate 100 is provided with two sets of shoulder straps 101, and the end of the shoulder straps 101 is provided with a rear plate 102. Three sets of waist belts 104 are installed on both sides of the rear plate 102, and hooks 204 are arranged at the end of the waist belts 104. Several sets of heat dissipation holes 103 are opened on the inner side of the front plate 100 and the rear plate 102.
[0034] Using the above solution: the shoulder strap 101 can place the device on the patient's shoulder and maintain a back-carrying position. By tightening the waist belt 104, the front clamp 100 and the rear clamp 102 can be pulled to clamp, thereby achieving the effect of supporting the patient's torso. The heat dissipation hole 103 can help dissipate heat and avoid the problem of eczema in the clamping area of the patient.
[0035] The working principle and usage process of this invention are as follows: The shoulder strap 101 is placed on the patient's shoulder, and then the six sets of connecting ropes 203 are pulled to combine the hook 204 with the hole at the end of the tightening belt 104. After the combination is completed, the patient holds the pressure ball 608 and applies pressure to inject gas into the air inlet hose 602. After entering, the gas enters the corresponding exhaust hose 603 through the switching valve 601. The gas enters the sealed tube 501 and pushes the piston disc 504 and the movable tube 503 to move laterally. At the same time, the lower telescopic inclined block 500 will move laterally. When moving, it will contact the fixed helical tooth block 400 to push the first ratchet module 402 to rotate. When rotating, the telescopic frame 302 will drive the fixed frame 301 and the winch 200 to rotate. When rotating, the connecting rope 203 will be pulled to reset. When pulled, it will be tightened to increase the clamping force of the splint. When disassembly is required, the patient touches the rotating disc 306 with both hands and applies pressure. The pressure will cause the telescopic frame 302 to retract into the fixed frame 301 through the squeezing column 305. After retraction, the telescopic frame 302 separates from the splicing groove 404. After separation, the winch 200 will lose its restraint and will be pulled back to its original position under the original contraction force. After repositioning, the connecting rope 203 will loosen. After loosening, the hook 204 will separate from the tightening belt 104. After separation, the front splint 100 and the rear splint 102 will be separated directly.
[0036] 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.
[0037] 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 spinal fracture orthotic brace, comprising a front splint (100), wherein a compression tightening assembly (001) is provided on one side of the front splint (100), characterized in that: The compression tightening assembly (001) includes a winch (200), and six sets of connecting ropes (203) are wound around the inner side of the winch (200). The compression tightening assembly (001) includes a sealing tube (501), and a movable tube (503) is slidably disposed in the middle of the sealing tube (501). Piston discs (504) are installed at both ends of the movable tube (503). The piston discs (504) are slidably disposed inside the movable tube (503). A telescopic inclined block is telescopically disposed at the lower end of the movable tube (503). 500), the extrusion tightening assembly (001) includes a first ratchet module (402), and a number of fixed helical teeth (400) are installed on the outer ring of the first ratchet module (402). A sliding column (507) is installed on the top of the movable tube (503), and a sliding frame (605) is slidably arranged on the outer side of the sliding column (507). Two sets of push columns (606) are respectively arranged on both sides of the sliding frame (605), and a bistable buckling beam (600) is arranged on the inner side of the two sets of push columns (606).
2. The orthotic brace for spinal fractures according to claim 1, characterized in that: The winch (200) has a winch box (201) on its outer side via a bearing, and the winch box (201) is fixedly installed on one side of the front clamp (100). Six sets of guide ends (202) are installed on the outer side of the winch box (201). The connecting rope (203) is movably arranged on the inner side of the guide ends (202), and a hook (204) is installed at the end of the connecting rope (203).
3. The orthotic brace for spinal fractures according to claim 2, characterized in that: A second ratchet module (403) is assembled on the inner side of the first ratchet module (402) away from the winch box (201). A drive box (401) is installed on the side of the winch box (201) away from the front clamp (100). The sealing tube (501) is fixedly installed on the inner side of the upper end of the drive box (401). Guide rods (406) are installed on both sides of the upper end of the drive box (401). The movable tube (503) is slidably arranged on the outer side of the guide rods (406).
4. The orthotic brace for spinal fractures according to claim 3, characterized in that: The second ratchet module (403) is fixedly installed on one side inside the drive box (401). An adjustment frame (405) is installed on the top of the drive box (401). The sliding frame (605) is slidably and reciprocally arranged inside the adjustment frame (405). A splicing groove (404) is opened in the middle of the first ratchet module (402).
5. The orthotic brace for spinal fractures according to claim 1, characterized in that: A telescopic cylinder (502) is installed in the middle of the movable tube (503), and a pressing block (506) is installed on the top of the telescopic inclined block (500). The pressing block (506) is slidably disposed inside the telescopic cylinder (502). The top of the pressing block (506) and the telescopic cylinder (502) are elastically connected by a pressing spring (505). One-way valves (508) are provided at both ends of the sealing tube (501).
6. The orthotic brace for spinal fractures according to claim 1, characterized in that: A squeeze unlocking assembly (002) is provided in the middle of the winch (200). The squeeze unlocking component (002) includes a fixed frame (301), and a telescopic frame (302) is telescopically arranged on the inner side of the fixed frame (301). The telescopic frame (302) is slidably spliced on the inner side of the splicing groove (404). A limit ring (303) is installed on one end of the telescopic frame (302) near the fixed frame (301), and the limit ring (303) is slidably arranged on the inner side of the fixed frame (301).
7. The orthotic brace for spinal fractures according to claim 6, characterized in that: The telescopic frame (302) and the fixed frame (301) are elastically connected by a return spring (304). A pressing column (305) is installed at one end of the telescopic frame (302) away from the fixed frame (301), and a rotating disk (306) is installed at one end of the pressing column (305) away from the fixed frame (301). The rotating disk (306) and the drive box (401) are elastically connected by a flexible sheet (300).
8. The orthotic brace for spinal fractures according to claim 7, characterized in that: A switching valve (601) is installed on the upper end of the drive box (401) near the winch box (201), and an air intake hose (602) is installed on the top of the switching valve (601). A pressure ball (608) is installed at the end of the air intake hose (602) away from the switching valve (601). Exhaust hoses (603) are installed on both sides of the switching valve (601), and the end of the exhaust hose (603) away from the switching valve (601) is fixedly connected to both ends of the sealing tube (501).
9. The orthotic brace for spinal fractures according to claim 8, characterized in that: The bottom of the switching valve (601) is provided with a valve lever (604), and the valve lever (604) is movably disposed in the middle of one side of the sliding frame (605). The two ends of the bistable buckling beam (600) are equipped with fixing rods (607), and the fixing rods (607) are fixedly installed on the top of the drive box (401).
10. The orthotic brace for spinal fractures according to claim 2, characterized in that: The upper end of the front plate (100) is provided with two sets of shoulder straps (101), and the end of the shoulder straps (101) is provided with a rear plate (102). Three sets of waist belts (104) are installed on both sides of the rear plate (102). The hooks (204) are arranged at the end of the waist belts (104). Several sets of heat dissipation holes (103) are opened on the inner side of the front plate (100) and the rear plate (102).