Ankle surgery inferior tibiofibular syndesmosis reduction fixing guider

Abstract

The invention discloses an ankle surgery inferior tibiofibular syndesmosis reduction fixing guider, and relates to the field of ankle surgery, the ankle surgery inferior tibiofibular syndesmosis reduction fixing guider comprises a protection plate, the bottom of the protection plate is rotatably connected with a bottom plate, the side face, close to the bottom plate, of the protection plate is connected with a binding belt, a dismounting and mounting mechanism comprises a first clamping groove, the first clamping groove is formed in the upper surface of an external connection block, and a second clamping groove is formed in the lower surface of the external connection block. The external connection blocks are symmetrically distributed up and down relative to the fixing block, and a through groove is formed in the side face of the connection arc block in a penetrating mode. According to the ankle surgery inferior tibiofibular combined reduction fixing guider, when the fixing block slides, the positioning plate can be driven to slide to the side face of the injured position of the ankle tibiofibular for extrusion and attachment, after the positioning plate is extruded, the position of the ankle can be fixed to prevent shaking, and after the fixing block is detached, the positioning plates of different specifications and shapes can be replaced; the position of the positioning plate can be adjusted up and down when the positioning plate is used for positioning, the adjusting efficiency is high, and the adaptability of the fixed guider to the ankle injury is improved.

Description

Technical Field

[0001] The invention relates to the technical field of foot and ankle surgery, in particular to a distal tibiofibular syndesmotic reduction and fixation guide for foot and ankle surgery. Background Art

[0002] Foot and ankle surgery mainly involves the diagnosis and treatment of the anatomical structure, function, diseases and injuries of the foot and ankle joint. The foot and ankle are located with the tibia and fibula. The tibia and fibula refer to the two main bones of the lower leg. When the tibia and fibula are injured, a joint reduction and fixation guide is required. This is an auxiliary tool used in tibia and fibula fracture or tibia and fibula injury surgery. Its main purpose is to help surgeons accurately reduce and fix the tibia and fibula during surgery to promote bone healing and restore function.

[0003] At present, there are still some shortcomings in the reduction and fixation guide. If there is no special guide and fixation device, the position of the Kirschner nail may be deviated during insertion: In order to overcome the problem of unstable fixation in foot and ankle surgery and the deflection of the insertion position of the Kirschner nail, a Chinese patent of the prior art (publication number: CN215018804U) discloses a guide for the reduction and fixation of the distal tibiofibular joint in foot and ankle surgery, which can adjust the position of the fixing structure by the distance between the sleeve frame and the inner frame through the set sleeve frame and the inner frame, so that the position of the positioning plate can be adjusted, so that the No. 1 guide cylinder and the No. 2 guide cylinder can correspond to the connection of the bone body, and when the doctor inserts the Kirschner nail, the Kirschner nail is guided, so that the Kirschner nail is not easy to deflect when inserted, and will not interfere with each other; The Chinese patent of the prior art (publication number: CN212788812U) discloses a syndesmotic reduction and fixation guide for foot and ankle surgery, which can push the handle to slide the slide buckle along the guide rail by setting a stretching structure torsion structure, and can stretch or push the top side of the foot plate with the cooperation of the stretching rod, and can change the forward and backward inclination of the foot, and can appropriately change the angle of the ankle. By rotating the wheel, the fixing buckle can be stretched, and the foot plate can be rotated, and the wheel on the other side can be released synchronously, and the left and right swing of the foot plate can be coordinated, and the ankle can be reset, fixed and guided in a controllable direction, and can assist in better treatment and recuperation; However, the reduction and fixation guides currently used still have certain shortcomings. The above-mentioned document 1 states that "the position of the fixed structure can be adjusted by the distance between the outer frame and the inner frame, so that the position of the positioning plate can be adjusted". This method uses a fixed pin for adjustment, which is cumbersome. Different people require different sizes of ankles. The fixed positioning plate is difficult to adapt to different types and is troublesome to use. The positioning strength of the positioning plate on the ankle is not high. The fixing strength of the ankle fixator on the ankle is not stable enough, which may cause secondary injury to the ankle. Therefore, the existing structure needs to be improved. Summary of the invention

[0004] The purpose of the present invention is to provide a tibiofibular syndesmotic reduction and fixation guide for foot and ankle surgery to solve the problems raised in the above background technology that the guide is not convenient for stably positioning the ankle and the fixator, different sizes of positioning plates are required for different injury locations and degrees, and the positioning plate is not convenient for height adjustment according to the injury location.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a foot and ankle surgery tibiofibular joint reduction and fixation guide, comprising a guard plate, the bottom of which is rotatably connected to a base plate, and the side of the guard plate close to the base plate is connected to a binding belt: The side of the guard plate close to the binding belt is provided with a guide groove, the guide grooves are symmetrically distributed with respect to the guard plate, the guide grooves have two groups, a first guide rod slides through the guide groove of one group, a connecting arc block is fixed to the end of the first guide rod away from the guard plate, the first guide rod is symmetrically distributed up and down about the connecting arc block, a second guide rod is fixed to the side of the connecting arc block close to the middle of the first guide rod, the second guide rod slides through the other group of guide grooves, a fixed block is fixed to the side of the connecting arc block away from the first guide rod, a positioning plate is connected to the side of the fixing block away from the connecting arc block, an oblique hole is penetrated from the side of the positioning plate, and an extrusion mechanism for improving the stability of the fixed guide is arranged inside the guide groove; An external block is fixed to the outside of the fixing block close to the connecting arc block, and a disassembly and assembly mechanism for replacing positioning plates of different specifications is arranged on the outside of the fixing block; A sliding groove is formed through the side of the fixing block close to the positioning plate, and an adjustment mechanism for improving the adaptability of the patient's foot and ankle is arranged inside the first guide rod.

[0006] Furthermore, the extrusion mechanism includes a threaded rod, the threaded rod passes through a bearing and rotates inside the guide groove and the guard plate, and the threaded rod is threadedly connected inside the second guide rod.

[0007] Furthermore, the disassembly and assembly mechanism includes a first snap-fit ​​groove, which is arranged on the upper surface of the external block, and the external block is symmetrically distributed up and down about the fixed block. A through groove is penetrated through the side of the connecting arc block, and a first connecting frame is arranged on the side of the connecting arc block close to the through groove.

[0008] Furthermore, a second connecting frame slides through the first connecting frame, a second engaging groove is symmetrically provided on the inner side of the second connecting frame, a rotating groove is provided inside the first connecting frame, a rotating wheel is rotatably connected inside the rotating groove, and a first engaging block slides through the rotating groove.

[0009] Furthermore, the first engaging blocks are symmetrically distributed about the rotating groove, a pull rope is connected to the side of the first engaging block close to the rotating wheel, the pull rope is wound around and connected to the surface of the rotating wheel, and a first spring is connected between the first engaging block and the rotating groove.

[0010] Furthermore, the first engaging block forms a telescopic structure with the rotating groove through the first spring, a connecting block is fixed to the side of the rotating wheel, the connecting block penetrates and rotates inside the rotating groove, and the rotating wheel, the first engaging block, the pull rope and the connecting block are transmission connected.

[0011] Furthermore, the adjustment mechanism includes a third engaging groove, the third engaging groove is arranged on a side of the sliding groove away from the positioning plate, the third engaging groove is arranged in multiple groups, and a sliding block slides through the interior of the sliding groove.

[0012] Furthermore, the sliding block is fixed to a side of the positioning plate close to the fixed block, and a telescopic groove is formed through the side of the sliding block close to the fixed block.

[0013] Furthermore, a second spring is connected inside the telescopic slot, and a T-shaped block is connected to the end of the second spring. The T-shaped block penetrates and slides inside the telescopic slot.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The foot and ankle surgical syndesmotic reduction and fixation guide can drive the positioning plate to slide to the side of the injured position of the foot and ankle syndesmotic injury for extrusion and fit when the fixing block slides. After the positioning plate is squeezed, the position of the ankle can be fixed to prevent shaking. After the fixing block is removed, positioning plates of different specifications and shapes can be replaced to adapt to various positions of foot and ankle syndesmotic injuries. When the positioning plate is positioned, its own position can be adjusted up and down, with high adjustment efficiency, which improves the adaptability of the fixing guide to foot and ankle injuries. 2. A first guide rod is provided, through which the positioning plate can be driven to move stably to prevent deviation. Since the two first guide rods are not deviated, the positioning plate can be driven to squeeze the ankle evenly, thereby improving the stability of ankle fixation; 3. A threaded rod is provided, through which two positioning plates can be driven simultaneously to squeeze the ankle synchronously, and the moving distance is the same, which can further improve the stability of ankle positioning and reduce the damage caused by ankle swing; 4. A first connecting frame and a second connecting frame are provided, and the first engaging groove can be engaged and positioned by telescopic sliding of the first connecting frame and the second connecting frame, so as to facilitate the disassembly and assembly of the positioning plate, and fix the two external blocks at the same time, without affecting the stability of the positioning plate; 5. A sliding block is provided, through which the position height of the positioning plate can be adjusted, so that the positioning plate is more suitable for fixing the injured part of the tibia and fibula, which can better ensure the accuracy of the surgical position and improve the protective strength after tibia and fibula surgery. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall front-view stereoscopic structure of the present invention; Figure 2 It is a schematic diagram of the overall side-view stereoscopic structure of the present invention; Figure 3 This is an enlarged three-dimensional structural schematic diagram of the positioning plate of the present invention; Figure 4 It is a schematic diagram of an enlarged three-dimensional structure of a threaded rod of the present invention; Figure 5 This is a schematic diagram of the split three-dimensional structure of the fixing block of the present invention; Figure 6 It is a schematic diagram of a cross-sectional three-dimensional structure of the first connecting frame of the present invention; Figure 7 For the present invention Figure 6 The enlarged three-dimensional structure diagram of the middle part A; Figure 8 This is an enlarged three-dimensional structural schematic diagram of the sliding block of the present invention; Fig. 9 It is a schematic diagram of the cross-sectional three-dimensional structure of the sliding block of the present invention.

[0016] In the figure: 1, guard plate; 2, bottom plate; 3, binding belt; 101, guide groove; 102, first guide rod; 103, connecting arc block; 104, second guide rod; 105, threaded rod; 106, fixed block; 107, positioning plate; 108, external block; 109, first engaging groove; 110, through groove; 111, first connecting frame; 112, second connecting frame; 113, second engaging groove; 114, rotating groove; 115, rotating wheel; 116, first engaging block; 117, pull rope; 118, first spring; 119, connecting block; 120, sliding groove; 121, third engaging groove; 122, sliding block; 123, telescopic groove; 124, second spring; 125, T-shaped block. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0018] like Figure 1-Figure 4The technical solution shown in the figure, the present invention provides the following technical solution: In order to solve the problem that the tibiofibular joint reduction and fixation guide is inconvenient to stably position the ankle and the fixation device, and it is easy to shake and cause secondary injuries, a squeezing mechanism is disclosed: The invention comprises a guard plate 1, wherein the bottom of the guard plate 1 is rotatably connected to a bottom plate 2, a binding belt 3 is connected to the side of the guard plate 1 close to the bottom plate 2, a guide groove 101 is provided on the side of the guard plate 1 close to the binding belt 3, and the guide grooves 101 are symmetrically distributed about the guard plate 1, and there are two groups of guide grooves 101, a first guide rod 102 is slidably penetrated inside the guide grooves 101 of one group, a connecting arc block 103 is fixed to the end of the first guide rod 102 away from the guard plate 1, the first guide rod 102 is symmetrically distributed up and down about the connecting arc block 103, a second guide rod 104 is fixed to the side of the middle part of the connecting arc block 103 close to the first guide rod 102, the second guide rod 104 penetrates and slides inside another group of guide grooves 101, and a fixing block 1 is fixed to the side of the connecting arc block 103 away from the first guide rod 102 06, the side of the fixed block 106 away from the connecting arc block 103 is connected with a positioning plate 107, the side of the positioning plate 107 is penetrated with an oblique hole, the guide groove 101 is provided with an extrusion mechanism for improving the stability of the fixed guide, the fixed block 106 is fixed with an external block 108 on the outside of the connecting arc block 103, the outside of the fixed block 106 is provided with a disassembly mechanism for replacing positioning plates 107 of different specifications, the side of the fixed block 106 close to the positioning plate 107 is penetrated with a sliding groove 120, the first guide rod 102 is provided with an adjustment mechanism for improving the adaptability of the patient's ankle, the extrusion mechanism includes a threaded rod 105, the threaded rod 105 is rotated in the guide groove 101 and the guard plate 1 through a bearing, and the threaded rod 105 is threadedly connected to the inside of the second guide rod 104; When the fixed guide is in use, the heel is placed on the upper surface of the base plate 2, and then the ankle and calf are pressed against the inner side of the guard plate 1, and then the leg is bound by the binding belt 3. At this time, the injured part of the ankle will be close to the inner side of the positioning plate 107, and the rotating threaded rod 105 can rotate through the guide groove 101. When the threaded rod 105 rotates, it can drive the second guide rod 104 to slide threadedly, and when the second guide rod 104 slides threadedly, it can slide through the guide groove 101. The sliding of the second guide rod 104 can also drive the connecting arc block 103 to move. When the connecting arc block 103 moves, it can drive the two first guide rods 102 to slide inside the other group of guide grooves 101, and when the connecting arc block 103 slides, it can drive the fixed block 106 to slide. When the fixing block 106 slides, it can drive the positioning plate 107 to slide to the side of the injured position of the ankle tibia and fibula for squeezing and fitting. After squeezing, the positioning plate 107 can fix the position of the ankle, so that the ankle can shake synchronously with the fixator, which can prevent damage caused by arbitrary swinging of the ankle. After fixation, the perforations on the side of the positioning plate 107 will be aligned with the surgical position of the tibia and fibula, and the surgical screws will be driven into the tibia and fibula through the perforations on the side of the positioning plate 107 to connect the composite parts. Since the perforations of the positioning plate 107 are oblique, the surgical screws will be guided by the perforations of the positioning plate 107 when being driven in, and are not easy to tilt, thereby realizing the resetting connection of the skeleton by the positioning plate 107, and improving the stability and fit of the ankle fixation by the positioning plate 107. Example

[0019] like Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 The technical solution shown in the figure, the present invention provides the following technical solution: In order to solve the problem that the number and position of surgical fixation nails required for fixation are different due to different injury positions and degrees of the tibiofibular joint reduction and fixation guide, different sizes and specifications of positioning plates 107 are required, based on the first embodiment, a disassembly and assembly mechanism is disclosed: The disassembly and assembly mechanism includes a first engaging groove 109, which is provided on the upper surface of the external block 108, and the external block 108 is symmetrically distributed about the fixed block 106. A through groove 110 is provided on the side of the connecting arc block 103, and a first connecting frame 111 is provided on the side of the connecting arc block 103 close to the through groove 110. A second connecting frame 112 is slidably penetrated inside the first connecting frame 111, and a second engaging groove 113 is symmetrically provided inside the second connecting frame 112. A rotating groove 114 is provided inside the first connecting frame 111, and a rotating wheel 115 is rotatably connected inside the rotating groove 114, and a first engaging block 116 is slidably penetrated inside the rotating groove 114. The first engaging block 116 is symmetrically distributed about the rotating groove 114. A pull rope 117 is connected to the side of the first engaging block 116 close to the rotating wheel 115. The pull rope 117 is wound and connected to the surface of the rotating wheel 115. A first spring 118 is connected between the first engaging block 116 and the rotating groove 114. The first engaging block 116 and the rotating groove 114 form a telescopic structure through the first spring 118. A connecting block 119 is fixed on the side of the rotating wheel 115. The connecting block 119 penetrates and rotates inside the rotating groove 114. The rotating wheel 115, the first engaging block 116, the pull rope 117 and the connecting block 119 are transmission connected. Before the fixed guide is repositioned for ankle surgery, the rotation The connecting block 119 can drive the rotating wheel 115 to rotate, and when the rotating wheel 115 rotates, it can rotate through the rotating groove 114. When the rotating wheel 115 rotates, the pull rope 117 can be wound. When the pull rope 117 is wound, the two first engaging blocks 116 can be pulled to move. When the first engaging block 116 moves, it can slide through the rotating groove 114 and the second engaging groove 113. When the first engaging block 116 slides, the first spring 118 can be squeezed. When the first engaging block 116 squeezes out of the second engaging groove 113, the second connecting frame 112 is pulled upward. When the second connecting frame 112 is pulled, it can slide through the inside of the first connecting frame 111. At the same time, the first connecting frame 111 and the second connecting frame 112 can both slide through the first locking groove 109. When the first connecting frame 111 and the second connecting frame 112 slide out of the first locking groove 109, they pull the fixed block 106. When the fixed block 106 is pulled, it can drive the external block 108 to move. When the external block 108 moves, it can slide through the through groove 110. When the external block 108 slides out of the through groove 110, the fixed block 106 can be disassembled. After the fixed block 106 is disassembled, the positioning plates 107 of different specifications and shapes can be replaced, so as to adapt to various positions of tibia and fibula injuries of the ankle, thereby improving the adaptability of the fixed guide to the ankle and making it more convenient to use. Example

[0020] like Figure 8 and Fig. 9The technical solution shown in the figure, the present invention provides the following technical solution: In order to solve the problem that the height required for the tibiofibular joint reduction and fixation guide is different for different injured positions, and the guide is difficult to adapt to different injured positions, on the basis of the second embodiment, an adjustment mechanism is disclosed: The adjusting mechanism includes a third engaging groove 121, which is arranged on a side of the sliding groove 120 away from the positioning plate 107. The third engaging groove 121 has multiple groups. A sliding block 122 is inserted and slidably penetrates the sliding groove 120. The sliding block 122 is fixed on a side of the positioning plate 107 close to the fixed block 106. A telescopic groove 123 is inserted and opened on the side of the sliding block 122 close to the fixed block 106. A second spring 124 is connected to the telescopic groove 123. A T-shaped block 125 is connected to the end of the second spring 124. The T-shaped block 125 penetrates and slides in the telescopic groove 123. Before being fixed, the positioning plate 107 of the fixing guide can have a height difference with the injured part of the tibia and fibula, and the T-shaped block 125 can be pushed to slide through the third engaging groove 121 and the telescopic groove 123. The T-shaped block 125 slides When the second spring 124 is moved, the second spring 124 can be squeezed, and the T-shaped block 125 can push the positioning plate 107 up and down when it is squeezed into the telescopic groove 123. When the positioning plate 107 is pushed, it can drive the sliding block 122 to move. When the sliding block 122 moves, it can slide through the sliding groove 120. When the sliding block 122 slides to the specified position, it can drive the T-shaped block 125 to move to the side of another group of third engaging grooves 121. At this time, the T-shaped block 125 is released and can be reset by the elastic force of the second spring 124 itself. When the T-shaped block 125 is reset, it can be engaged and positioned with the third engaging groove 121. When the T-shaped block 125 is positioned, it can drive the positioning plate 107 to be positioned. When the positioning plate 107 is positioned, its own position can be adjusted up and down, and the adjustment efficiency is high, which further improves the adaptability of the fixed guide to ankle injuries.

[0021] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A syndesmotic reduction and fixation guide for foot and ankle surgery, comprising a guard plate (1), the bottom of the guard plate (1) being rotatably connected to a base plate (2), and a binding belt (3) being connected to the side of the guard plate (1) close to the base plate (2), characterized in that: A guide groove (101) is provided on the side of the guard plate (1) close to the binding belt (3). The guide grooves (101) are symmetrically distributed with respect to the guard plate (1). There are two groups of guide grooves (101). A first guide rod (102) slides through the inside of the guide groove (101) of one group. A connecting arc block (103) is fixed to the end of the first guide rod (102) away from the guard plate (1). The first guide rod (102) is symmetrically distributed with respect to the connecting arc block (103) in the upper and lower directions. The connecting arc block (103) is close to the first guide rod (102). A second guide rod (104) is fixed to the side of the middle part of the guide rod (102), the second guide rod (104) penetrates and slides inside another group of guide grooves (101), a fixing block (106) is fixed to the side of the connecting arc block (103) away from the first guide rod (102), a positioning plate (107) is connected to the side of the fixing block (106) away from the connecting arc block (103), an oblique hole penetrates the side of the positioning plate (107), and a squeezing mechanism for improving the stability of the fixed guide is arranged inside the guide groove (101); An external connection block (108) is fixed to the outside of the fixing block (106) close to the connecting arc block (103), and a disassembly and assembly mechanism for replacing positioning plates (107) of different specifications is provided on the outside of the fixing block (106); A sliding groove (120) is provided through the side surface of the fixing block (106) close to the positioning plate (107), and an adjustment mechanism for improving the adaptability of the patient's foot and ankle is arranged inside the first guide rod (102).

2. A tibiofibular syndesmotic reduction and fixation guide for foot and ankle surgery according to claim 1, characterized in that: The extrusion mechanism comprises a threaded rod (105), wherein the threaded rod (105) passes through a bearing and rotates inside the guide groove (101) and the guard plate (1), and the threaded rod (105) is threadedly connected inside the second guide rod (104).

3. The guide for reduction and fixation of the distal tibiofibular syndesmotic joint in foot and ankle surgery according to claim 1, characterized in that: The disassembly and assembly mechanism comprises a first engaging groove (109), the first engaging groove (109) being provided on the upper surface of the external block (108), the external block (108) being symmetrically distributed up and down with respect to the fixed block (106), a through groove (110) being provided through the side surface of the connecting arc block (103), and a first connecting frame (111) being provided on the side surface of the connecting arc block (103) close to the through groove (110).

4. The guide for reduction and fixation of the distal tibiofibular syndesmotic joint in foot and ankle surgery according to claim 3, characterized in that: A second connecting frame (112) slides through the first connecting frame (111), a second engaging groove (113) is symmetrically provided on the inner side of the second connecting frame (112), a rotating groove (114) is provided inside the first connecting frame (111), a rotating wheel (115) is rotatably connected inside the rotating groove (114), and a first engaging block (116) slides through the rotating groove (114).

5. The guide for reduction and fixation of the distal tibiofibular syndesmotic joint in foot and ankle surgery according to claim 4, characterized in that: The first engaging block (116) is symmetrically distributed with respect to the rotating groove (114); a pull rope (117) is connected to a side of the first engaging block (116) close to the rotating wheel (115); the pull rope (117) is wound around and connected to the surface of the rotating wheel (115); and a first spring (118) is connected between the first engaging block (116) and the rotating groove (114).

6. The guide for reduction and fixation of the distal tibiofibular syndesmotic joint in foot and ankle surgery according to claim 4, characterized in that: The first engaging block (116) forms a telescopic structure with the rotating groove (114) via a first spring (118); a connecting block (119) is fixed to the side of the rotating wheel (115); the connecting block (119) penetrates and rotates inside the rotating groove (114); and the rotating wheel (115), the first engaging block (116), the pull rope (117) and the connecting block (119) are in transmission connection.

7. The guide for reduction and fixation of the distal tibiofibular syndesmotic joint in foot and ankle surgery according to claim 1, characterized in that: The adjustment mechanism comprises a third engaging groove (121), the third engaging groove (121) being arranged on a side of the sliding groove (120) away from the positioning plate (107), the third engaging groove (121) being arranged in a plurality of groups, and a sliding block (122) slidingly passing through the interior of the sliding groove (120).

8. The guide for reduction and fixation of the distal tibiofibular syndesmotic joint in foot and ankle surgery according to claim 7, characterized in that: The sliding block (122) is fixed to a side of the positioning plate (107) close to the fixed block (106), and a telescopic groove (123) is provided through the side of the sliding block (122) close to the fixed block (106).

9. The guide for reduction and fixation of the distal tibiofibular syndesmotic joint in foot and ankle surgery according to claim 8, characterized in that: A second spring (124) is connected inside the telescopic slot (123), and an end of the second spring (124) is connected to a T-shaped block (125), and the T-shaped block (125) penetrates and slides inside the telescopic slot (123).

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