Elastic retaining type denture securement device

Abstract

This invention belongs to the field of denture stabilization and installation technology, and discloses a flexible clamping denture stabilization and installation device, including a denture body. The denture body has multiple flexible clamping parts, each of which includes a holding rod fixedly connected to the inner wall of the bottom end of the denture body. A clamping block is fixedly connected to the bottom end of the holding rod, and the clamping block can intermittently clamp onto the implanted staples in the patient's dental arch. Through a combination of a micro DC motor, a threaded cylinder, a beveled conical groove, and a beveled clamping plate, the clamping force of the rubber abutment on the holding rod can be precisely adjusted by presetting the number of motor rotations via a controller. This adapts to different abutment tooth conditions and solves the problem of uncontrollable clamping force in traditional methods. The elastic pressure-relieving structure of the magnetic groove plate, the beveled rubber rod, and the double ball bar combines magnetic positioning and tilting buffering functions, further enhancing the dynamic adaptability of the holding rod and the staples, and reducing the risk of denture loosening.

Description

Technical Field

[0001] This invention belongs to the field of denture stabilization technology, specifically a flexible clamping denture stabilization device. Background Technology

[0002] Dentures are devices used to replace missing teeth. They play a role in many aspects, including restoring chewing function, improving aesthetics, maintaining oral structure, preventing adjacent teeth from shifting, and enhancing speech clarity. They are of great significance to people with missing teeth and can improve their oral condition and quality of life in many ways. In dental clinical treatment, denture installation mostly relies on traditional clasp fixation or adhesive fixation methods. However, existing installation techniques have many shortcomings. Traditional clasp fixation methods have poor adaptability and insufficient stability, and are prone to loosening and wobbling after installation. On the other hand, adhesive fixation methods are inconvenient to disassemble and have high maintenance costs. When using adhesive to fix dentures, the adhesive is difficult to remove after it has hardened. During subsequent denture repair, replacement or cleaning, it is easy to cause secondary damage to the abutment teeth and surrounding periodontal tissues. In addition, the adhesive is prone to aging and failure in the moist environment of the oral cavity for a long time, which will lead to denture falling off and require frequent re-bonding, increasing the patient's treatment costs and pain. Summary of the Invention

[0003] To address the problems mentioned in the background art, the present invention provides a flexible clasp-type denture stabilization device.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a flexible clamping denture stabilization device, comprising a denture body, wherein the denture body is provided with a plurality of flexible clamping parts, each of the flexible clamping parts including a holding rod fixedly connected to the inner wall of the bottom end of the denture body, a clamping block fixedly connected to the bottom end of the holding rod, the clamping block being intermittently clamped to a stapled tube implanted in the human dental bed, a pressing block fixedly connected to the bottom end of the holding rod, ball-head abutments being slidably connected to the four outer walls of the pressing block, the other end of each ball-head abutment being fixedly connected to the inner wall of the stapled tube, and a spring being jointly and fixedly connected between the inner wall of the stapled tube and each ball-head abutment for providing initial elastic pressure on the holding rod that is fixed to the denture body; the stapled tube is also provided with a clamping structure for stabilizing and limiting the holding rod. The clamping structure includes three inclined cone clamps, each with a rubber abutment fixedly connected to its inner wall, and the other end of each rubber abutment can intermittently and tightly fit against the outer wall of the holding rod.

[0005] Preferably, a slot is provided in the bottom cylinder of the nailing component, and the locking block can be intermittently inserted into the slot.

[0006] Preferably, the clamping structure further includes a miniature pressure sensor fixedly connected to the inner cavity of the bottom end of the nailed cylinder, and the top end of the miniature pressure sensor and the bottom end of the clamping block can be intermittently fitted and connected.

[0007] Preferably, a miniature DC motor is provided inside the cylinder near the top of the nailed cylinder, and an extension rod is fixedly connected to the shaft of the miniature DC motor, while a grooved wheel column is fixedly connected to the body of the extension rod.

[0008] Preferably, a rotating wheel is rotatably connected to the grooved wheel column, a threaded cylinder is fixedly connected to the rotating wheel, a threaded groove plate is threadedly connected to the cylinder body of the threaded cylinder, the outer wall of the threaded groove plate is fixedly connected to the inner wall of the nailed cylinder, and the bottom end of the micro DC motor is fixedly connected to the top side plate of the threaded groove plate.

[0009] Preferably, the bottom inner wall of the threaded cylinder is provided with a sloping conical groove, and three sloping conical plates are rotatably connected to the inner wall of the sloping conical groove. Each of the three sloping conical plates is fixedly connected to a rubber abutment, and the other end of each rubber abutment can be intermittently connected to the outer wall of the holding rod.

[0010] Preferably, each of the inclined cone clamps is fixedly connected to an elastic telescopic member on its outer wall, and the other end of each elastic telescopic member is fixedly connected to the inner wall of the nailed cylinder.

[0011] Preferably, four ball-head abutments are intermittently attached to the inner wall of the nailing cylinder, and the ball end of each ball-head abutment can be intermittently attached to and slidably connected to the four sides of the pressing block. Each ball-head abutment is also fixedly connected to the inner wall of the nailing cylinder with a spring. The inner wall of the nailed cylinder is also provided with an elastic pressure-relieving structure.

[0012] Preferably, the elastic pressure-relieving structure includes multiple oblique rubber rods that are inserted and fixedly connected in the slot, and four sets of horizontal rubber rods are also fixedly connected in the inner wall of the slot. The other end of each oblique rubber rod and each set of horizontal rubber rods can be tightly fitted and connected to the outer wall of the block.

[0013] Preferably, four ear plates are fixedly connected to the inner wall of the nailing cylinder, and a set of inclined groove rubber rods are fixedly connected to the top plate of each ear plate. A magnetic groove plate is fixedly connected to the other end of each set of inclined groove rubber rods. Each magnetic groove plate can be magnetically connected to the holding rod intermittently. Each of the magnetic slot plates and ear plates is movably connected to a double ball rod, and each ear plate has a ring cylinder fixedly connected to its top plate. The ring cylinder and the double ball rod can be intermittently fitted and connected.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention utilizes a combination of a micro DC motor, a threaded cylinder, an inclined conical groove, and an inclined conical clamping plate for driving and clamping. The controller can preset the number of motor rotations and precisely adjust the clamping force of the rubber abutment on the holding rod to adapt to different tooth conditions, thus solving the problem of uncontrollable clamping force in traditional methods. The elastic pressure-relieving structure of the magnetic groove plate, the inclined groove rubber rod, and the double ball rod combines magnetic positioning and tilting buffer functions, further enhancing the dynamic adaptability of the holding rod and the nailing sleeve and reducing the risk of denture loosening.

[0015] This invention utilizes gelatin-modified oblique rods, horizontal rods, and oblique groove rods to correspond to the periodontal ligament fiber structures such as root apical fibers and horizontal fibers, respectively. Combined with elastic expansion components and springs, it achieves multi-directional dispersion and elastic recovery of chewing force, avoids bone damage caused by hard contact, and significantly improves wearing comfort and long-term stability. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the overall planar structure of the elastic locking part of the present invention; Figure 3 For the present invention Figure 2 A magnified view of the structure at point A in the middle; Figure 4 This is a schematic diagram of the overall cross-sectional structure of the threaded cylinder of the present invention; Figure 5 This is a schematic diagram of the overall structure of the inclined groove rubber rod of the present invention.

[0017] In the picture: 1. Denture body; 2. Elastic locking part; 201. Holding rod; 202. Locking block; 203. Pressing block; 204. Stapling sleeve; 205. Locking groove; 206. Miniature pressure sensor; 207. Miniature DC motor; 208. Grooved wheel column; 209. Rotary wheel; 210. Threaded cylinder; 211. Threaded groove plate; 212. Inclined conical groove; 213. Inclined conical clamp plate; 214. Rubber abutment plate; 215. Elastic telescopic component; 216. Ball head abutment rod; 217. Spring; 218. Inclined rubber rod; 219. Horizontal rubber rod; 220. Ear plate; 221. Inclined groove rubber rod; 222. Magnetic groove plate; 223. Double ball rod; 224. Ring cylinder. Detailed Implementation

[0018] 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.

[0019] like Figures 1 to 5 As shown, the present invention provides a flexible clasp-type denture stabilization device, including a denture body 1. The denture body 1 has multiple flexible clasping parts 2. Each flexible clasp-type part 2 includes a holding rod 201 fixedly connected to the inner wall of the bottom end of the denture body 1. A locking block 202 is fixedly connected to the bottom end of the holding rod 201. The locking block 202 can intermittently engage with a staple tube 204 implanted in the human dental arch. A pressing block is fixedly connected to the bottom end of the holding rod 201. 203, ball-head abutment rods 216 are slidably connected to the outer walls of the four ends of the pressing block 203. The other end of each ball-head abutment rod 216 is fixedly connected to the inner wall of the nailing cylinder 204. A spring 217 is also fixedly connected between the inner wall of the nailing cylinder 204 and each ball-head abutment rod 216 for initial elastic pressure on the holding rod 201 of the fixed denture body 1. The nailing cylinder 204 is also provided with a clamping structure for stable and limited positioning of the holding rod 201. The clamping structure includes three inclined cone clamps 213. Each inclined cone clamp 213 has a rubber abutment 214 fixedly connected to its inner wall. The other end of each rubber abutment 214 can be intermittently and tightly connected to the outer wall of the rod 201. The bottom end of the nailed cylinder 204 has a slot 205, and the locking block 202 can be intermittently inserted into the slot 205.

[0020] Using the above method: the denture body 1 is vertically lowered to contact the lower jawbone. This process allows the retaining bar 201 in the denture body 1 to move downwards into the implant-installed staple sleeve 204 in the jawbone, such as... Figure 2 As shown, when the bottom end of the screw rod 202 is engaged in the slot 205 and the rod 201 moves the screw rod 202 and the pressing block 203 simultaneously into the nailed cylinder 204, the pressing block 203 will simultaneously slide and squeeze the four ball-headed rods 216, causing the spring 217 to deform elastically. The passively moving threaded cylinder 210 will press and tighten the multiple inclined cone plates 213 through the inclined cone groove 212 opened in the inner wall. This drives the inclined cone plates 213 to contact the rubber abutment 214 fixed in the inner wall to hold the rod 201, providing a stable and undamaged limit.

[0021] The clamping structure also includes a miniature pressure sensor 206 fixedly connected to the inner cavity of the bottom end of the nailed cylinder 204. The top end of the miniature pressure sensor 206 and the bottom end of the clamping block 202 can be intermittently fitted together. A miniature DC motor 207 is provided in the inner cavity of the nailed cylinder 204 near the top. An extension rod is fixedly connected to the shaft of the miniature DC motor 207, and a grooved wheel column 208 is fixedly connected to the body of the extension rod. A rotating wheel 209 is fitted and rotatably connected to the grooved wheel column 208. A threaded cylinder 210 is fixedly connected to the rotating wheel 209. A threaded grooved plate 211 is threadedly connected to the body of the threaded cylinder 210. The outer wall of the threaded grooved plate 211 and the nailed cylinder 204 are connected together. The inner wall of 4 is fixedly connected, the bottom end of the micro DC motor 207 is fixedly connected to the top side plate of the threaded groove plate 211, the bottom inner wall of the threaded cylinder 210 is provided with a sloping conical groove 212, and three sloping conical clamps 213 are rotatably connected to the inner wall of the sloping conical groove 212. Rubber abutments 214 are fixedly connected to the inner walls of the three sloping conical clamps 213, and the other end of each rubber abutment 214 can be intermittently connected to the outer wall of the holding rod 201. An elastic telescopic member 215 is fixedly connected to the outer wall of each sloping conical clamp 213, and the other end of each elastic telescopic member 215 is fixedly connected to the inner wall of the nailed cylinder 204.

[0022] Using the above scheme: the pressure block 203 simultaneously slides and compresses the four ball-headed abutments 216, causing the spring 217 to deform elastically under pressure. The ball-headed abutments 216 then abut against the inner wall of the nail-attached cylinder 204, thereby generating elastic pressure on the pressure block 203 fixed on the holding rod 201. This effectively absorbs and disperses impact force, protecting the mechanism from rigid collision damage. Simultaneously, the lowered locking block 202, inserted into the locking slot 205, abuts against the miniature pressure sensor 206, converting the pressure signal into an electrical signal. The miniature pressure sensor 206, with a volume controlled within 10mm × 5mm × 3mm, enables precise control without affecting the wearing comfort of the denture body 1. Figure 2 and Figure 4As shown, the operation of the micro DC motor 207 drives the extension rod and the grooved wheel column 208 fixed on the extension rod to rotate forward together. In the passively rotating state, the grooved wheel column 208 will frictionally drive the rotating wheel 209 to rotate. The rotating wheel 209 will drive the threaded cylinder 210 to rotate downward in the threaded groove plate 211. When the grooved wheel column 208 is passively rotated in the reverse direction, it can again frictionally drive the rotating wheel 209 and the threaded cylinder 210 to move upward and reset. At that time, the passively downward-moving threaded cylinder 210 will press and tighten the multiple inclined cone clamps 213 through the inclined cone groove 212 opened in the inner wall, thereby driving the inclined cone clamps 213 to drive the rubber abutment plate 2 fixed in the inner wall. 14. Contact clamping rod 201 provides a stable and undamaged limit. As the passively tightening and moving inclined cone clamp 213 moves, it stretches the elastic telescopic member 215 that limits it, causing it to undergo elastic deformation. The setting of the elastic telescopic member 215 also facilitates the subsequent direct drive of the unforced inclined cone clamp 213 to automatically reset. As the threaded cylinder 210 moves downward, the rubber abutment 214 will be subjected to different degrees of pressure on the holding rod 201, thereby generating different clamping and pressing forces with the holding rod 201. The micro DC motor 207 that drives the threaded cylinder 210 to move downward can be controlled in advance by setting a controller to control the number of rotations of the micro DC motor 207, achieving the benefit of adaptive and stable clamping.

[0023] The inner wall of the nailing cylinder 204 is also intermittently fitted with four ball-head abutments 216. The ball end of each ball-head abutment 216 can intermittently slide and fit against the four sides of the pressing block 203. Each ball-head abutment 216 is fixedly connected to the inner wall of the nailing cylinder 204 with a spring 217. The inner wall of the nailing cylinder 204 is also provided with an elastic pressure-relieving structure, which includes multiple oblique rubber rods 218 inserted and fixedly connected in the slot 205. The inner wall of the slot 205 is also fixedly connected with four sets of horizontal rubber rods 219. The other end of each oblique rubber rod 218 and each set of horizontal rubber rods 219 can fit against the slot 203. The outer wall of block 202 is tightly fitted and connected. Four ear plates 220 are fixedly connected to the inner wall of the nailed cylinder 204. A set of inclined groove rubber rods 221 are fixedly connected to the top plate of each ear plate 220. A magnetic groove plate 222 is fixedly connected to the other end of each set of inclined groove rubber rods 221. The plate of each magnetic groove plate 222 can be magnetically fitted and connected to the holding rod 201 intermittently. A double ball rod 223 is movably connected between each magnetic groove plate 222 and ear plate 220. A ring cylinder 224 is fixedly connected to the top plate of each ear plate 220. The ring cylinder 224 and the rod of the double ball rod 223 can be intermittently fitted and connected.

[0024] The above solution is adopted: such as Figure 2 , Figure 3 as well as Figure 5As shown, during the downward movement of the holding rod 201, it will slide into contact with multiple magnetic slot plates 222. The magnetic slot plates 222 that are in contact will tilt and shift at a fixed point on the ear plate 220 according to the double ball rod 223. This shift will cause contact with the cylinder wall of the ring cylinder 224. At the same time, the inclined groove rubber rod 221 will deform. When the magnetism of the magnetic slot plate 222 and the metal material of the holding rod 201 come into contact, they will attract each other, so that the magnetic slot plate 222 is tightly attached to the holding rod 201. The inclined rubber rod 218, horizontal rubber rod 219 and inclined groove rubber rod 221 attached to the card block 202 are used to simulate the periodontal ligament fibers connecting the teeth and the gums. The fiber bundles in the periodontal ligament suspend the teeth in the alveolar socket, maintaining stability, distributing chewing force, and preventing bone damage caused by direct contact with hard structures. The oblique rubber rods 218, lateral rubber rods 219, and oblique groove rubber rods 221 are all modified gelatin-based materials, possessing viscoelasticity and biocompatibility that match natural periodontal ligament fibers. They can be processed into fiber-like structures through 3D printing, electrospinning, and other technologies to accurately simulate the mechanical buffering characteristics of the periodontal ligament (such as elastic recovery and load distribution capacity), and have good cell compatibility, which can reduce irritation to oral tissues. They are very suitable for use as buffer structures in denture installation equipment, achieving an elastic and stable clamping effect in combination with the above.

[0025] One point to add is that when the denture body 1 is removed from the mouth, the micro DC motor 207 can be started to rotate in reverse by a remote control, and the denture body 1 can be pulled out by itself. The inclined conical groove 212 represents the alveolar ridge fiber in the periodontal ligament, the inclined rubber bar 218 represents the apical fiber, and the transverse rubber bar 219 represents the transverse fiber.

[0026] The working principle and usage process of this invention are as follows: The denture body 1 is manually placed into the oral cavity and vertically lowered to contact the lower jawbone. This process allows the holding rod 201 in the denture body 1 to move downwards into the implant-installed staple sleeve 204 in the jawbone until the bottom locking block 202 engages with the slot 205. Simultaneously, as the holding rod 201 moves the locking block 202 and the pressure block 203 downwards into the staple sleeve 204, the pressure block 203 slides and compresses the four ball-headed abutments 216, causing the spring 217 to elastically deform. At the same time, the ball-headed abutments 216 abut against the inner wall of the staple sleeve 204, thus generating elastic pressure on the pressure block 203 fixed on the holding rod 201. Simultaneously, the locking block 202, which moves downwards and engages with the slot 205, abuts against the micro pressure sensor 206, causing it to convert the pressure signal into an electrical signal. The micro DC motor 20... The operation of 7 will drive the extension rod and the grooved wheel column 208 fixed on the extension rod to rotate forward together. The grooved wheel column 208 in the passive rotation state will cause the rotating wheel 209 to rotate due to friction. The rotating wheel 209 will drive the threaded cylinder 210 to rotate and move downward in the threaded groove plate 211. At that time, the passively moving threaded cylinder 210 will press and tighten multiple inclined cone clamps 213 through the inclined cone groove 212 opened in the inner wall. This will drive the inclined cone clamps 213 to contact the rubber abutment plate 214 fixed in the inner wall to clamp the holding rod 201, providing a stable and undamaged limit. As the passively tightened and moved inclined cone clamps 213 move, they will stretch the elastic telescopic member 215 that limits them, causing it to undergo elastic deformation. As the threaded cylinder 210 moves downward, the rubber abutment plate 214 will be subjected to different degrees of pressure on the holding rod 201, thereby generating different forces of clamping and pressing with the holding rod 201. As the holding rod 201 moves downward, it will slide into contact with multiple magnetic slot plates 222. The magnetic slot plates 222 that are in contact will tilt and shift at a fixed point on the ear plate 220 according to the double ball rod 223. This shift will cause contact with the cylinder wall of the ring cylinder 224. At the same time, the inclined groove rubber rod 221 will deform. When the magnetism of the magnetic slot plate 222 and the metal material of the holding rod 201 come into contact, they will attract each other, so that the magnetic slot plate 222 is tightly attached to the holding rod 201. The inclined rubber rod 218, horizontal rubber rod 219 and inclined groove rubber rod 221 attached to the locking block 202 are used to simulate the periodontal ligament fibers connecting the teeth and the gums. The above combination achieves the effect of elastic and stable locking.

[0027] 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.

[0028] 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 flexible retaining denture stabilization device, comprising a denture body (1), characterized in that: The denture body (1) is provided with multiple elastic locking parts (2), each of which includes a holding rod (201) fixedly connected to the inner wall of the bottom end of the denture body (1). A locking block (202) is fixedly connected to the bottom end of the holding rod (201), and the locking block (202) can intermittently engage with the staple tube (204) implanted in the human dental bed. A pressing block (203) is fixedly connected to the bottom end of the holding rod (201). Ball-head abutments (216) are slidably connected to the outer walls of all four ends. The other end of each ball-head abutment (216) is fixedly connected to the inner wall of the nailing sleeve (204). A spring (217) is also fixedly connected between the inner wall of the nailing sleeve (204) and each ball-head abutment (216) for initial elastic pressure on the holding rod (201) of the fixed denture body (1). The nailing sleeve (204) is also provided with a clamping structure for stabilizing and limiting the holding rod (201). The clamping structure includes: three inclined cone clamps (213), a rubber abutment (214), and a miniature pressure sensor (206). The miniature pressure sensor (206) is fixedly connected to the inner cavity of the bottom cylinder of the nailed cylinder (204). The top of the miniature pressure sensor (206) and the bottom of the clamping block (202) can be intermittently fitted and connected. A miniature DC motor (207) is provided inside the cylinder near the top of the nailed cylinder (204). An extension rod is fixedly connected to the shaft of the miniature DC motor (207), and a grooved wheel column (208) is fixedly connected to the body of the extension rod. A rotating wheel (209) is rotatably connected to the grooved wheel column (208), and a threaded cylinder (210) is fixedly connected to the rotating wheel (209). A threaded groove plate (211) is threadedly connected to the body of the threaded cylinder (210). The outer wall of the threaded groove plate (211) is fixedly connected to the inner wall of the nailed cylinder (204), and the bottom end of the miniature DC motor (207) is fixedly connected to the top side plate of the threaded groove plate (211). The bottom inner wall of the threaded cylinder (210) is provided with a sloping conical groove (212). Three sloping conical plates (213) are rotatably connected to the inner wall of the sloping conical groove (212). A rubber abutment (214) is fixedly connected to the inner wall of each of the three sloping conical plates (213). The other end of each rubber abutment (214) can be intermittently connected to the outer wall of the holding rod (201).

2. The flexible retaining denture stabilizing device according to claim 1, characterized in that: The bottom end of the nailed cylinder (204) is provided with a slot (205), and the locking block (202) can be intermittently inserted into the slot (205).

3. The flexible retaining denture stabilizing device according to claim 1, characterized in that: Each of the inclined cone clamps (213) has an elastic telescopic member (215) fixedly connected to its outer wall, and the other end of each elastic telescopic member (215) is fixedly connected to the inner wall of the nailed cylinder (204).

4. The flexible-holding denture stabilizing device according to claim 1, characterized in that: The inner wall of the nailed cylinder (204) is also intermittently fitted with four ball-head abutments (216). The ball end of each ball-head abutment (216) can be intermittently fitted and slidably connected with the four sides of the pressing block (203). Each ball-head abutment (216) is also fixedly connected with a spring (217) to the inner wall of the nailed cylinder (204). The inner wall of the nailed cylinder (204) is also provided with an elastic pressure-relieving structure.

5. The flexible-holding denture stabilizing device according to claim 4, characterized in that: The elastic pressure-relieving structure includes multiple oblique rubber rods (218) that are inserted and fixedly connected in the slot (205). Four sets of horizontal rubber rods (219) are also fixedly connected in the inner wall of the slot (205). The other end of each oblique rubber rod (218) and each set of horizontal rubber rods (219) can be tightly fitted and connected to the outer wall of the block (202).

6. The flexible-holding denture stabilizing device according to claim 1, characterized in that: The inner wall of the nailed cylinder (204) is fixedly connected with four ear plates (220). Each ear plate (220) has a set of inclined groove rubber rods (221) fixedly connected to its top plate. Each set of inclined groove rubber rods (221) has a magnetic groove plate (222) fixedly connected to its other end. Each magnetic groove plate (222) can be magnetically connected to the holding rod (201) intermittently. Each of the magnetic slot plates (222) and ear plates (220) is movably connected to a double ball rod (223). Each ear plate (220) is fixedly connected to a ring cylinder (224) at its top end. The ring cylinder (224) and the double ball rod (223) can be intermittently fitted together.

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