Eye axis length compensation device

Abstract

The present invention provides an eye axis length compensation device, which relates to the technical field of medical machinery and comprises a suspension mechanism and a wide-angle auxiliary lens system. The suspension mechanism comprises a connecting rod and a first compensation member, wherein one end portion of the connecting rod is fixedly connected to the first compensation member, and the other end portion thereof is rotatably connected to an accessory mounting platform of a surgical microscope. The wide-angle auxiliary lens system comprises a lens mounting member, a lens assembly, an auxiliary connecting member, a rotating assembly, and a second compensation member, wherein the lens assembly is fixedly arranged on the lens mounting member, one end portion of the auxiliary connecting member is rotatably connected to the lens mounting member by means of the rotating assembly, the other end portion thereof is fixedly connected to the second compensation member, the second compensation member is slidably connected to the first compensation member, and the central axis of the lens assembly is parallel to the second compensation member. The present invention allows a doctor to accurately adjust the axial length of the eyes for different patients by introducing an eye axis length compensation knob and a locking device having a highly quantitative adjustment function, thereby improving the applicability.

Description

An axial length compensation device Technical Field

[0001] This invention relates to the field of medical device technology, and more specifically, to an axial length compensation device. Background Technology

[0002] In retinal surgery, wide-angle auxiliary lens systems are commonly used to provide clear fundus images while maintaining a certain working distance. Existing wide-angle auxiliary lens systems typically include a focusing lens suspended below the surgical microscope. This focusing lens adjusts its distance from the surgical microscope objective via a mechanical structure to match the patient's axial length and the imaging position of the fundus. However, the main limitation of this system is the limited focusing range of the focusing lens. This is especially true when the patient has refractive abnormalities (such as high myopia or hyperopia), when gas-fluid exchange is being performed, or when observing fundus protrusions during retinal surgery. In these cases, the focusing lens often cannot provide sufficient adjustment range to accommodate these changes, resulting in unclear fundus images and affecting the precision and efficiency of the surgery.

[0003] Based on the shortcomings of the existing technology, there is an urgent need for an axial length compensation device. Summary of the Invention

[0004] The purpose of this invention is to provide an axial length compensation device to improve the aforementioned problems. To achieve this purpose, the technical solution adopted by this invention is as follows:

[0005] This application provides an axial length compensation device, characterized in that it includes: a suspension mechanism and a wide-angle auxiliary lens system. The suspension mechanism includes a connecting rod and a first compensation member. One end of the connecting rod is fixedly connected to the first compensation member, and the other end is rotatably connected to an accessory mounting platform of a surgical microscope. The wide-angle auxiliary lens system includes a lens mounting member, a lens assembly, an auxiliary connecting member, a rotating assembly, and a second compensation member. The lens assembly is fixedly mounted on the lens mounting member. One end of the auxiliary connecting member is rotatably connected to the lens mounting member through the rotating assembly, and the other end is fixedly connected to the second compensation member. The second compensation member is slidably connected to the first compensation member, and the central axis of the lens assembly is parallel to the second compensation member.

[0006] Furthermore, the second compensation member is provided with a sliding part and an adjustment device, and the first compensation member is provided with a sliding groove and a locking device that cooperate with the sliding part.

[0007] Furthermore, the sliding part includes a flat sliding area and a cylindrical area arranged coaxially. The adjusting device includes a lead screw section and a compensation knob. One end of the flat sliding area is fixedly connected to the auxiliary lens arm, and the other end is fixedly connected to the cylindrical area. One end of the cylindrical area away from the flat sliding area is fixedly connected to the lead screw section. The compensation knob has a screw hole that mates with the lead screw section. The compensation knob is rotatably connected to the lead screw section.

[0008] Furthermore, the first compensation component includes a sliding mounting base, which is fixedly connected to the connecting rod. The sliding mounting base has a first sliding groove and a second sliding groove that are interconnected. The width of the first sliding groove is greater than the diameter of the column area, and the width of the second sliding groove is less than the width of the first sliding groove but greater than the minimum width of the flat sliding area. A through hole that mates with the column area is provided on the inner side of the second sliding groove.

[0009] Furthermore, the locking device includes a fixed base plate, a spring, and an elastic locking pin that are fixedly connected in sequence. The inner side of the second slide groove is provided with a recessed surface that cooperates with the fixed base plate. The fixed base plate is fixedly disposed in the recessed surface. The elastic locking pin includes a cylinder and a pressure plate disposed at the bottom of the cylinder. The sliding mounting seat is provided with a blind hole that cooperates with the cylinder. The elastic locking pin is disposed in the blind hole.

[0010] Furthermore, the sliding part also includes a directional positioning block, which is fixedly disposed between the lead screw section and the column area. One end of the directional positioning block coincides with the circular cross-section of the column area, and the other end is rectangular in shape and protrudes outward along the diameter direction of the column area.

[0011] Furthermore, an alignment mark is provided on the end face of the sliding mounting base that is parallel to the directional positioning, and a compensation value mark corresponding to the alignment mark is provided on the sliding mounting base.

[0012] Furthermore, the lens mounting component includes a cantilever and lens mounting rings fixedly disposed at both ends of the cantilever, and the lens assembly is fixedly disposed within the lens mounting rings.

[0013] Furthermore, the rotating assembly includes a flange bearing and a rivet. The cantilever has a first through hole at its center that mates with the flange bearing. The auxiliary connector has a second through hole at its center that mates with the rivet. The flange bearing is disposed in the first through hole of the cantilever, and the rivet is disposed in the second through hole. The fixed part of the flange bearing is fixedly connected to the cantilever, and the rotating part of the flange bearing is fixedly connected to the rivet.

[0014] Furthermore, the rotating assembly also includes two spring balls. A first blind hole is provided on the outer side of the first through hole to accommodate the spring balls. A second blind hole is provided on the end face of the auxiliary connector near the cantilever to cooperate with the spring balls. The spring balls are disposed in the first blind hole.

[0015] The beneficial effects of this invention are as follows:

[0016] This invention provides an additional compensation mechanism for wide-angle auxiliary lens systems by introducing an axial length compensation knob and locking device with highly quantitative adjustment capabilities. This allows doctors to make precise adjustments for the axial length of different patients, improving applicability. By setting a sliding mounting base and orientation positioning block, the stability and correct orientation of the lens during surgery are ensured, thus providing surgeons with a clearer and more stable field of vision.

[0017] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing embodiments of the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 is a schematic diagram of the axial length compensation device described in the embodiment of this application;

[0020] Figure 2 is a schematic diagram of the suspension mechanism structure described in the embodiment of this application;

[0021] Figure 3 is a schematic diagram of the wide-angle auxiliary lens system described in the embodiment of this application;

[0022] Figure 4 is an exploded view of the wide-angle auxiliary lens system described in the embodiment of this application;

[0023] Figure 5 is an enlarged view of point I in Figure 1;

[0024] Figure 6 is a schematic diagram of the locking device described in the embodiment of this application.

[0025] The diagram shows the following markings: 1. Suspension mechanism; 11. Connecting rod; 12. First compensation component; 121. Locking device; 1211. Fixed base plate; 1212. Spring; 1213. Elastic locking pin; 122. Sliding mounting seat; 1221. First slide groove; 1222. Second slide groove; 1223. Compensation value indicator; 2. Wide-angle auxiliary lens system; 21. Lens mounting component; 211. Cantilever; 212. Lens mounting ring; 22. Lens assembly; 23. Auxiliary connecting component; 24. Rotating assembly; 241. Flange bearing; 242. Rivet; 243. Spring ball; 25. Second compensation component; 251. Sliding part; 2511. Flat sliding area; 2512. Column area; 2514. Direction positioning block; 2515. Alignment indicator; 252. Adjustment device; 2521. Lead screw section; 2522. Compensation knob. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0027] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0028] As shown in Figure 1, this embodiment provides an axial length compensation device, including a suspension mechanism 1 and a wide-angle auxiliary lens system 2. The core function of the suspension mechanism 1 is to provide a stable and flexible support structure, enabling the wide-angle auxiliary lens to be adjusted as needed to adapt to different surgical requirements. The suspension mechanism 1 includes a connecting rod 11 and a first compensation member 12. One end of the connecting rod 11 is fixedly connected to the first compensation member 12, and the other end is rotatably connected to the accessory mounting platform of the surgical microscope. This rotatable connection design allows the entire device to be flexibly adjusted during surgery to adapt to different angles and positions, thereby ensuring that the lens system can be aligned with the patient's eye. The wide-angle auxiliary lens system 2 is the core visual component of this device. The wide-angle auxiliary lens system 2 includes a lens mounting member 21, a lens assembly 22, an auxiliary connector 23, a rotating assembly 24, and a second compensation member 25. The lens assembly 22 is fixedly mounted on the lens mounting member 21. The design of the auxiliary connector 23 allows one end to be rotatably connected to the lens mounting member 21 via the rotating assembly 24, enabling the alternating use of different lenses as needed during surgery. The other end is fixedly connected to the second compensation member 25. The second compensating member 25 is slidably connected to the first compensating member 12, and the central axis of the lens assembly 22 is parallel to the second compensating member 25. This sliding connection design provides further adjustment flexibility for the lens assembly 22. Through the interaction of the first compensating member 12 and the second compensating member 25, this device can precisely adjust the position of the lens to match the patient's axial length, thereby providing a clearer field of vision for fundus surgery. The combination of rotational and sliding connections increases operational flexibility during surgery, allowing surgeons to adjust the lens position according to surgical needs and optimize the surgical field of vision. The parallel design of the central axis of the lens assembly 22 and the second compensating member 25 ensures the consistency of the lens's optical axis with the patient's axial length, which is crucial for achieving high-quality fundus imaging.

[0029] Preferably, as shown in Figures 1 and 3, the second compensator 25 is provided with a sliding part 251 and an adjusting device 252. The sliding part 251 allows the lens component to move smoothly along a specific trajectory, achieving precise position adjustment. Furthermore, the adjusting device 252 allows the operator to precisely control the degree and position of movement of the sliding part 251 to adapt to specific changes in the patient's axial length. The first compensator 12 is designed with a groove that mates with the sliding part 251, providing a defined path for the sliding part 251 and ensuring its linearity and accuracy. The locking device 121 is used to fix the sliding part 251 in the appropriate position, which is particularly important during surgery as it prevents positional displacement due to accidental contact or other external factors, ensuring the precision and safety of the surgery. These optimized designs enable the axial length compensation device not only to provide the necessary adjustment functions but also to ensure the accuracy and safety of the entire surgical procedure, significantly improving medical outcomes and the patient's treatment experience.

[0030] Preferably, as shown in Figures 2 and 3, the sliding part 251 includes a flat sliding area 2511 and a cylindrical area 2512 coaxially arranged. The adjusting device includes a lead screw section 2521 and a compensation knob 2522. One end of the flat sliding area 2511 is fixedly connected to the auxiliary lens arm, and the other end is fixedly connected to the cylindrical area 2512. One end of the cylindrical area 2512 away from the flat sliding area 2511 is fixedly connected to the lead screw section 2513. The compensation knob 2522 has a screw hole that mates with the lead screw section 2521, and the compensation knob 2522 is rotatably connected to the lead screw section 2521. Furthermore, the second compensation component 25 includes a sliding mounting base 122, which is fixedly connected to the connecting rod 11. The sliding mounting base 122 has a first sliding groove 1221 and a second sliding groove 1222 that are connected to each other. The width of the first sliding groove 1221 is greater than the diameter of the column area 2512, and the width of the second sliding groove 1222 is less than the width of the first sliding groove 1221, but greater than the minimum width of the flat sliding area 2511. A through hole that mates with the column area 2512 is provided on the inner side of the second sliding groove 1222.

[0031] It should be noted that the flat sliding area 2511 is located at the bottom of the sliding part 251, and its width is specifically designed to match the second groove 1222 of the suspension mechanism 1. This design ensures that the irregular main arm can be smoothly installed and removed through the opening of the suspension mechanism 1, providing basic installation support. The flat sliding area 2511 connects to the cylindrical area 2512, which provides structural stability and rigidity, enabling the sliding part 251 to withstand various forces during surgical operations. The other end of the cylindrical area 2512 is fixedly connected to the lead screw section 2521, which in turn works with the compensation knob 2522. The compensation knob 2522 has a screw hole that is threadedly connected to the lead screw section 2521, allowing the sliding part 251 to move precisely in a straight line along the lead screw section 2521 when the compensation knob 2522 is rotated. This design allows the surgeon to make fine adjustments during surgery by rotating the compensation knob 2522, achieving precise compensation for the axial length of the eye. The coaxially arranged flat sliding area 2511 and cylindrical area 2512 ensure the stable movement of the sliding part 251 within the groove, preventing rotation and offset, and providing higher operational stability.

[0032] Preferably, as shown in Figure 6, the locking device 121 includes a fixed base plate 1211, a spring 1212, and an elastic locking pin 1213, which are fixedly connected in sequence. A recessed surface that mates with the fixed base plate 1211 is provided on the inner side of the second slide groove 1222. The fixed base plate 1211 is fixedly disposed within the recessed surface. The elastic locking pin 1213 includes a cylinder and a pressure plate disposed at the bottom of the cylinder. A blind hole that mates with the cylinder is provided on the sliding mounting base 122, and the elastic locking pin 1213 is disposed within the blind hole. The fixed base plate 1211 is the basic part of the locking device 121, and preferably, it is fixed to the suspension mechanism 1 or the sliding mounting base 122 by welding. The fixed base plate 1211 provides a stable platform for mounting components of other locking mechanisms. The spring 1212 is connected to the fixed base plate 1211, and its main purpose is to provide the necessary pressure and restoring force for the elastic locking pin 1213. In this way, spring 1212 not only supports the dynamic movement of the locking pin, but also ensures that the locking pin can automatically return to its original position when no external force is applied. The elastic locking pin 1213 is the core of this locking device 121, comprising a cylinder and a pressure plate disposed at the bottom of the cylinder. The cylinder is designed to slide into or out of its mating blind hole, while the pressure plate is used to achieve the locking function. When the locking pin is pressed into the blind hole, the pressure plate contacts the recessed surface or other locking surface of the light column, thereby fixing the entire device. Through the combined use of the fixed base plate 1211 and the recessed surface, and the engagement of the elastic locking pin 1213 with the blind hole, this locking device 121 effectively fixes the irregular main arm or other critical components in a specific operating position, preventing movement caused by vibration or excessive operating force. Furthermore, the locking device 121 allows the operator to quickly and accurately lock or unlock components when needed, which is particularly important for the operation of medical equipment requiring frequent adjustments.

[0033] Preferably, as shown in Figures 1 and 4, the sliding part 251 further includes a directional positioning block 2514. The directional positioning block 2514 is fixedly disposed between the lead screw section 2521 and the cylindrical section 2512. One end of the directional positioning block 2514 coincides with the circular cross-section of the cylindrical section 2512, which helps ensure its alignment within the device. The other end is rectangular and protrudes outward along the diameter of the cylindrical section 2512. This design provides additional mechanical support, ensuring that the directional positioning block 2514 maintains the correct orientation during movement and preventing rotation or offset. The main function of the directional positioning block 2514 is to ensure the directional stability of the sliding part 251 during adjustment. The protruding rectangular end restricts the rotation or lateral movement of the component through physical contact, thereby maintaining the set path and orientation. The addition of the directional positioning block 2514 enhances the stability of the device and the accuracy of operation.

[0034] Preferably, as shown in Figure 5, an alignment mark 2515 is provided on the end face of the directional positioning block 2514 parallel to the sliding mounting base 122, and a compensation value mark 1223 corresponding to the alignment mark 2515 is provided on the sliding mounting base 122. The length of the lead screw section 2521 and the thickness of the directional positioning block 2514 together determine the adjustment stroke of the axial length compensation device. The compensation value mark 1223 provides doctors with a visual reference for adjusting the device to a specific compensation position. The marks typically include the center position, the upper 1 / 2 stroke, and the lower 1 / 2 stroke, which are preset according to the stroke limits of the structure. Furthermore, for wide-angle auxiliary lenses with different parameters, the axial length compensation value corresponding to each compensation value mark 1223 position is different, but for wide-angle compensation lenses with fixed parameters, the axial length compensation value corresponding to each scale position is unique. Preferably, a corresponding axial length compensation value reference table can be provided for doctors' reference based on the configured wide-angle auxiliary lens parameters.

[0035] Preferably, as shown in FIG4, the lens mounting component 21 includes a cantilever 211 and a lens mounting ring 212 fixedly disposed at both ends of the cantilever 211, and the lens assembly 22 is fixedly disposed within the lens mounting ring 212.

[0036] Preferably, as shown in Figure 4, the rotating assembly 24 includes a flange bearing 241, a rivet 242, and two spring balls 243. The cantilever 211 has a first through hole at its center that mates with the flange bearing 241, and a first blind hole outside the through hole that accommodates the spring balls 243. The auxiliary connector 23 has a second blind hole on its end face near the cantilever 211 that mates with the spring balls 243. The auxiliary connector 23 has a second through hole at its center that mates with the rivet 242. The flange bearing 241 is disposed within the first through hole of the cantilever 211, the rivet 242 is disposed within the second through hole, and the spring balls 243 are disposed within the first blind hole. The fixed part of the flange bearing 241 is fixedly connected to the cantilever 211, and the rotating part of the flange bearing 241 is fixedly connected to the rivet 242. The cantilever 211 is designed to support different lenses at both ends. By rotating the cantilever 211, it is possible to switch between two different types of lenses. This design is particularly suitable for situations where it is necessary to quickly change the observation method or imaging technology during surgery. A flange bearing 241 is installed in a through hole at the center of the cantilever 211, working with rivets 242 to ensure stability during rotation. This structural design allows the cantilever 211 to bear the weight of the lens without sacrificing stability, while maintaining smooth rotation. The key function of the spring ball bearing 243 is to quickly and precisely lock the lens when the cantilever 211 rotates to a specific position (e.g., 180 degrees). This is achieved by pre-setting the spring ball bearing 243 in a blind hole in the cantilever 211. When the cantilever 211 rotates to the corresponding position, the spring ball bearing 243 is compressed and quickly expands into the corresponding blind hole on the auxiliary connector 23, thereby achieving locking. Through the combination of the spring ball bearing 243 and the flange bearing 241, the cantilever 211 can lock quickly and precisely when rotated to the desired position, ensuring the stability of the lens during use and preventing visual field shift or vibration during surgery. At the same time, this design takes into account the smoothness of operation and physical feedback, ensuring that the surgeon can feel the precise locking of the lens position during surgery.

[0037] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0038] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A device for compensating for axial length, characterized in that, include: A suspension mechanism (1) comprising a connecting rod (11) and a first compensating member (12), wherein one end of the connecting rod (11) is fixedly connected to the first compensating member (12), and the other end is rotatably connected to the accessory mounting platform of the surgical microscope; and A wide-angle auxiliary lens system (2) includes a lens mounting component (21), a lens assembly (22), an auxiliary connector (23), a rotating component (24), and a second compensation component (25). The lens assembly (22) is fixedly mounted on the lens mounting component (21). One end of the auxiliary connector (23) is rotatably connected to the lens mounting component (21) through the rotating component (24), and the other end is fixedly connected to the second compensation component (25). The second compensation component (25) is slidably connected to the first compensation component (12). The central axis of the lens assembly (22) is parallel to the second compensation component (25).

2. The axial length compensation device according to claim 1, characterized in that: The second compensation member (25) is provided with a sliding part (251) and an adjusting device (252), and the first compensation member (12) is provided with a sliding groove and a locking device (121) that cooperate with the sliding part (251).

3. The axial length compensation device according to claim 2, characterized in that: The sliding part (251) includes a flat sliding area (2511) and a cylindrical area (2512) arranged coaxially. The adjusting device (252) includes a lead screw section (2521) and a compensation knob (2522). One end of the flat sliding area (2511) is fixedly connected to the auxiliary connector (23), and the other end is fixedly connected to the cylindrical area (2512). One end of the cylindrical area (2512) away from the flat sliding area (2511) is fixedly connected to the lead screw section (2521). The compensation knob (2522) has a screw hole that mates with the lead screw section (2521). The compensation knob (2522) is rotatably connected to the lead screw section (2521).

4. The axial length compensation device according to claim 3, characterized in that: The first compensation component (12) includes a sliding mounting base (122), which is fixedly connected to the connecting rod (11). The sliding mounting base (122) has a first sliding groove (1221) and a second sliding groove (1222) that are connected to each other. The width of the first sliding groove (1221) is greater than the diameter of the column area (2512). The width of the second sliding groove (1222) is less than the width of the first sliding groove (1221) and greater than the minimum width of the flat sliding area (2511). The inner side of the second sliding groove (1222) has a through hole that mates with the column area (2512).

5. The axial length compensation device according to claim 4, characterized in that: The locking device (121) includes a fixed base plate (1211), a spring (1212), and an elastic locking pin (1213) that are fixedly connected in sequence. The second slide groove (1222) has a recessed surface that cooperates with the fixed base plate (1211) on its inner side. The fixed base plate (1211) is fixedly installed in the recessed surface. The elastic locking pin (1213) includes a cylinder and a pressure plate installed at the bottom of the cylinder. The sliding mounting base (122) has a blind hole that cooperates with the cylinder. The elastic locking pin (1213) is installed in the blind hole.

6. The axial length compensation device according to claim 4, characterized in that: The sliding part (251) further includes a directional positioning block (2514), which is fixedly disposed between the lead screw section (2513) and the cylindrical area (2512). One end of the directional positioning block (2514) coincides with the circular cross section of the cylindrical area (2512), and the other end is rectangular in shape and protrudes outward along the diameter direction of the cylindrical area (2512).

7. The axial length compensation device according to claim 6, characterized in that: The directional positioning block (2514) is provided with an alignment mark (2515), and the sliding mounting base (122) is provided with a compensation value mark (1223) corresponding to the alignment mark (2515).

8. The axial length compensation device according to any one of claims 1-7, characterized in that: The lens mounting component (21) includes a cantilever (211) and a lens mounting ring (212) fixedly disposed at both ends of the cantilever (211), and the lens assembly (22) is fixedly disposed within the lens mounting ring (212).

9. The axial length compensation device according to claim 8, characterized in that: The rotating assembly (24) includes a flange bearing (241) and a rivet (242). The cantilever (211) has a first through hole at its center that mates with the flange bearing (241). The auxiliary connector (23) has a second through hole at its center that mates with the rivet (242). The flange bearing (241) is disposed in the first through hole of the cantilever (211), and the rivet (242) is disposed in the second through hole. The fixing part of the flange bearing (241) is fixedly connected to the cantilever (211), and the rotating part of the flange bearing (241) is fixedly connected to the rivet (242).

10. The axial length compensation device according to claim 9, characterized in that: The rotating assembly (24) also includes two spring balls (243). A first blind hole is provided on the outside of the first through hole to accommodate the spring balls (243). A second blind hole is provided on the end face of the auxiliary connector (23) near the cantilever (211) to cooperate with the spring balls (243). The spring balls (243) are disposed in the first blind hole.

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