Endoscopic intervertebral space planer tool device

Abstract

The utility model belongs to but not limited to the technical field of medical instruments, and discloses an endoscopic intervertebral space planer tool device which comprises a connecting part, a working part is arranged at one end of the connecting part, and a universal connecting interface is arranged at the other end of the connecting part and is in butt joint with a power system; the inner diameter of the working part is larger than that of the connecting part, the working part expands at the far end, the diameter of the working part cutter head is larger than that of the connecting part outer sleeve rod, and a working part shell and the cutter head are both provided with openings. A communicated hollow pipeline is arranged between the inner core rod of the connecting part and the tool bit of the working part and communicated with the connector, and after the power system is connected with the connector, the inner core rod and the tool bit axially move and rotate in the outer sleeve rod and the shell. And the suction function is realized through the working part shell opening, the tool bit opening and a hollow pipeline between the connecting part inner core rod and the working part tool bit. When being used for treating the intervertebral space, the device can be inserted into the intervertebral space under the microscope to finish one-time treatment, so that the operation efficiency is improved, and the operation difficulty is reduced.

Description

Technical Field

[0001] This utility model belongs to, but is not limited to, the field of medical device technology, and particularly relates to an endoscopic intervertebral disc shaving device. Background Technology

[0002] Spinal interbody fusion surgery is an effective treatment for degenerative spinal diseases. Traditional open spinal interbody fusion surgery allows for the manipulation of the intervertebral space with larger instruments under a wide field of vision; however, open surgery is highly invasive, involves significant bleeding, and poses a considerable challenge to patients. Furthermore, open surgery relies solely on touch to manipulate the intervertebral space and endplates, without direct visualization, leading to inaccurate assessment of the extent of manipulation and affecting the fusion rate. To overcome the shortcomings of traditional open surgery, minimally invasive endoscopic spinal interbody fusion surgery has emerged in recent years. Minimally invasive endoscopic spinal interbody fusion surgery does not require extensive dissection of paravertebral muscles, resulting in less trauma and bleeding. It also allows for direct visualization of the nucleus pulposus and cartilaginous endplates within the intervertebral space, ensuring efficient fusion. However, currently, due to the limited scope of the endoscope, only small instruments such as nucleus pulposus forceps and curettes are used to manipulate the nucleus pulposus and cartilaginous endplates within the intervertebral space. These instruments need to be repeatedly inserted and withdrawn around the nerves, resulting in low efficiency, long processing time, and a high risk of nerve damage. This requires long-term technical expertise and significantly increases the workload of surgeons and the anesthesia time for patients. Currently, arthroscopic shaving tools commonly used in sports medicine can shave soft tissue and simultaneously aspirate tissue debris. However, the thickness and length of arthroscopic shaving tools are not compatible with spinal endoscopy systems. More importantly, arthroscopic shaving tools are simple straight-cylinder shapes, which can only handle the nucleus pulposus tissue within the intervertebral space in the confined space under endoscopy, making it difficult to thoroughly handle the cartilaginous endplates that are concave in the middle and bulging at the edges.

[0003] Therefore, there is an urgent need to develop a tool that can efficiently and quickly complete the nucleus pulposus tissue and depressed cartilaginous endplate within the intervertebral space under endoscopic guidance in a confined space. This would greatly shorten the time of minimally invasive endoscopic spinal interbody fusion surgery, reduce the difficulty of the surgery, improve the safety of the surgery, reduce the workload of medical staff, facilitate the promotion of minimally invasive technology, and benefit a large number of patients. Utility Model Content

[0004] To address the problems existing in the prior art, this utility model provides an endoscopic intervertebral disc planer device.

[0005] This invention is implemented as follows: an endoscopic intervertebral disc reshaping device includes a connecting part, one end of which is provided with a working part, and the other end of which is provided with a universal connection interface for docking with a power system. The working part includes a shell and a cutting head. The inner diameter of the working part is larger than that of the connecting part, and it is distally bulging. The diameter of the cutting head of the working part is larger than that of the outer sleeve of the connecting part. The tip of the shell of the working part adopts a blunt rounded design and can be equipped with a 0.1mm-4mm protective rail. Both the shell of the working part and the cutting head are provided with openings. The connecting part includes an outer sleeve and an inner core. A hollow pipe is provided between the inner core of the connecting part and the cutting head of the working part, and it is connected to a connector. After the power system is connected to the connector, the inner core and the cutting head can move and rotate axially within the outer sleeve and the shell, and achieve a suction function through the opening of the shell of the working part, the opening of the cutting head, and the hollow pipe between the inner core of the connecting part and the cutting head of the working part.

[0006] Furthermore, the outer sleeve of the connecting part matches the inner core rod, and can be straight or made into a crescent shape of 0-45 degrees.

[0007] Furthermore, the outer shell of the working part matches the cutting head of the working part, and its shape can be spherical, elliptical, cylindrical, olive-shaped, etc.

[0008] Furthermore, both the working part housing and the cutting head can be single-sided, double-sided, or multi-sided openings, and the cutting edge type can be flat, beveled semi-circular, single serrated, double serrated, etc.

[0009] Furthermore, the working head can be an open, hollow, bladed structure, or it can be a solid grinding head with a surface shape such as a watermelon or gravel that matches the outer shell of the working part.

[0010] Furthermore, a smooth coating can be added between the inner and outer layers.

[0011] Furthermore, a dedicated suction pipe can be designed at the outer sleeve of the connecting part.

[0012] Furthermore, the device is made of metallic materials such as titanium alloy, stainless steel, shape memory alloy, and high-strength steel, or non-metallic materials such as ceramics; the manufacturing process includes molding, laser cutting, thermoforming, welding and precision machining.

[0013] Furthermore, the outer sleeve of the connecting part and the outer shell of the working part can be an integral structure or made into one piece through welding, bonding or other processes; the inner core rod of the connecting part and the cutter head of the working part can be an integral structure or made into one piece through welding, bonding or other processes.

[0014] Furthermore, the working part is 3-30mm long, and red, green, and yellow conspicuous lines are set at 10mm (or 1mm near the opening of the outer shell), 20mm, and 30mm from the tip of the working part to the connecting part. Directional indicator marks can be set at the connecting part's outer shell to indicate the direction of the working part's outer shell opening.

[0015] Based on the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solution to be protected by this utility model are as follows:

[0016] First, the cutting head and matching outer sleeve of this invention are elliptical in shape at the distal end, allowing for easy and thorough treatment of the cartilaginous endplate, which has a raised edge and a concave center, within the confined space under the endoscope without much or no movement. Red, green, and yellow warning lines are provided to provide real-time monitoring and alerts to the surgeon regarding the depth of entry, highlighting potential dangers. The yellow line indicates a depth of 30mm into the intervertebral space, preventing excessive depth treatment and effectively reducing the risk of injury to abdominal organs from the annulus fibrosus during blind surgical manipulation. The red line indicates the opening position of the working section, preventing shallow insertion into the intervertebral space and potential nerve damage from the planer. A 0.1-4mm protective rail is designed at the distal end of the working section to prevent excessive depth treatment, which could lead to the planer penetrating the annulus fibrosus structure and damaging adjacent organs. Furthermore, this device can be used in conjunction with an endoscope to simultaneously plan the nucleus pulposus and cartilaginous endplate within the intervertebral space, allowing for real-time observation of the treatment process. The processed tissue debris can be aspirated through a hollow tube, improving efficiency. By applying this invention to treat intervertebral discs, the procedure can be completed in one go after endoscopic insertion. It effectively avoids the risk of nerve irritation and damage caused by repeated insertion and removal of instruments such as nucleus pulposus forceps and curettes during the treatment of intervertebral discs, thus simplifying the surgical procedure and improving surgical safety.

[0017] Secondly, as supplementary evidence of the inventive step of the claims of this utility model, it is also reflected in the following important aspects:

[0018] (1) The expected benefits and commercial value of the technical solution of this utility model after transformation are as follows:

[0019] After the technical solution of this utility model is transformed, it can easily and thoroughly treat the cartilaginous endplate with raised edges and a concave center in a confined space under endoscopy without or with only slight oscillation, and simultaneously aspirate the nucleus pulposus debris and cartilaginous endplate debris, thereby improving surgical efficiency and reducing the difficulty of surgical operation. After the technical solution of this utility model is transformed, it is expected to become an essential tool for endoscopic intervertebral discectomy, similar to the sports medicine joint shaver, and will be widely promoted in the field of endoscopic fusion.

[0020] (2) The technical solution of this utility model solves a technical problem that people have long wanted to solve but have never been able to solve successfully:

[0021] Existing techniques for endoscopic fusion surgery involve using only tiny nucleus pulposus forceps and curettes to treat the nucleus pulposus and cartilaginous endplates within the intervertebral space. This requires repeated insertion and removal of instruments around the nerve, resulting in low efficiency, long treatment time, and a high risk of nerve damage. It also necessitates long-term technical expertise and significantly increases the workload for surgeons and anesthesia time for patients. This new invention features red, green, and yellow warning lines. Under endoscopic guidance, the surgeon can monitor and be alerted to the depth of insertion, highlighting potentially dangerous depths. The yellow line indicates a depth of 30mm into the intervertebral space, preventing excessive depth treatment and effectively reducing the risk of injury to abdominal organs from the annulus fibrosus during blind surgical manipulation. The red line indicates the opening position of the working section, preventing shallow insertion and potential nerve damage from the shaving tool. This new invention allows for easy and thorough treatment of the cartilaginous endplate, which has a raised edge and a concave center, within the confined space under endoscopic guidance without or with only slight movement. The procedure is monitored in real time, and debris is aspirated through a hollow tube, improving efficiency. By applying this invention to treat intervertebral discs, the procedure can be completed in one go after endoscopic insertion. It effectively avoids the risk of nerve irritation and damage caused by repeated insertion and removal of instruments such as nucleus pulposus forceps and curettes during the treatment of intervertebral discs, thus simplifying the surgical procedure and improving surgical efficiency and safety.

[0022] (3) The technical solution of this utility model overcomes technical bias:

[0023] Currently available shaving systems on the market are simple, straight-cylinder-shaped. In the confined space under endoscopy, they can only process the nucleus pulposus tissue within the intervertebral space, making it difficult to thoroughly process the cartilaginous endplates with raised edges and a concave center. Therefore, shaving systems are considered unsuitable for endoscopic spinal fusion surgery. This invention features a cutting head and a matching outer sleeve with an enlarged elliptical distal end, allowing for easy and thorough processing of the cartilaginous endplates with raised edges and a concave center within the confined space under endoscopy without much or no movement. This improves surgical efficiency and reduces the difficulty of the procedure. In the future, this shaving system is expected to become an essential tool for endoscopic intervertebral disc resection, similar to sports medicine joint shaving devices. Attached Figure Description

[0024] Figure 1 This is a structural diagram of the endoscopic intervertebral disc planer device provided in this embodiment of the utility model;

[0025] Figure 2 This is an internal structural diagram of the endoscopic intervertebral disc planer device provided in this embodiment of the utility model;

[0026] Figure 3 This is a schematic diagram of the operation of the endoscopic intervertebral disc planer device provided in this embodiment of the utility model;

[0027] In the diagram: 1. Connector; 2. Connecting part; 2-1. Outer rod; 2-2. Inner core rod; 2-3. Scale marking line on the outer rod; 3. Working part; 3-1. Outer shell; 3-2. First opening of the cutter head; 3-3. Opening of the outer shell; 3-4. Distal blunt rounded protective sheath; 3-5. Second opening of the cutter head; 3-6. Cutter head. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this utility model.

[0029] like Figure 1 As shown, this embodiment of the utility model provides an endoscopic intervertebral disc shaving device, which consists of three main parts: a connector 1, a connecting part 2, and a working part 3. Figure 2 As shown, the connecting part 2 includes an outer sleeve rod 2-1 and an inner core rod 2-2. The outer sleeve rod 2-1 and the inner core rod 2-2 are matched, and can be made into a straight cylindrical shape or a meniscus structure of 0-45 degrees according to the usage requirements, providing flexible surgical angle adjustment capabilities. The working part 3 includes a housing 3-1 and a blade 3-6. The two are highly matched, and the internal diameter is designed such that the inner diameter of the working part is larger than the inner diameter of the connecting part, and the blade diameter of the working part is larger than the diameter of the outer sleeve rod of the connecting part. That is, the blade of the working part is higher than the cut surface of the outer sleeve rod of the connecting part, which is convenient for treating cartilage endplates with raised edges and concave centers. The shape of the working part can be spherical, elliptical, cylindrical, olive-shaped, etc., and the design of various shapes (such as spherical, elliptical, cylindrical, etc.) ensures that the device is suitable for different surgical needs.

[0030] Tip and blade design

[0031] The tip of the working part housing 3-1 features a blunt, rounded design and can be fitted with a 0.1mm-4mm protective guard to prevent accidental damage to surrounding tissues. The cutting edge opening and design are diverse; both the working part housing 3-1 and the cutting head 3-6 can have single-sided, double-sided, or multi-sided openings. Cutting edge types include flat edges, beveled semi-circular edges, single serrated edges, and double serrated edges, supporting different cutting edge structures, angles, and sharpness requirements. Adjustments to the rotation angle and sharpness improve planing or grinding efficiency.

[0032] Materials and Manufacturing Processes

[0033] The device is primarily constructed from metallic materials such as titanium alloy, stainless steel, shape memory alloy, and high-strength steel, or non-metallic materials such as ceramics, ensuring strength and durability. Manufacturing processes include molding, laser cutting, thermoforming, welding, and precision machining to ensure structural accuracy and surface finish. The connecting outer sleeve rod 2-1 and the working outer shell 3-1 can be integrally formed or manufactured as a single unit through welding, bonding, or other processes; the connecting inner core rod 2-2 and the working blade head 3-6 can also be integrally formed or manufactured as a single unit through welding, bonding, or other processes. A smooth coating can be added between the inner and outer sleeves to significantly improve the device's smoothness, reduce intraoperative resistance, and facilitate operation.

[0034] Planing chip management and connection function

[0035] A hollow tube is designed between the inner core rod 2-2 of the connecting part and the cutter head 3-6 of the working part, which can carry away planing debris with the water flow and keep the surgical area clean. In addition, a dedicated suction tube is also designed at the outer sleeve rod 2-1 of the connecting part. The tail end is designed with a universal connection interface to support docking with common power systems on the market, ensuring the applicability and compatibility of the device.

[0036] Depth markers and direction indicators

[0037] The working section length can be customized from 3-30mm according to requirements. Conspicuous red, green, and yellow marking lines are set at 10mm (or 1mm proximal to the opening of the outer shell), 20mm, and 30mm from the tip of the working section to the connecting section. Operators can use these markings to accurately observe the instrument insertion depth and avoid damage to nearby vital tissues and organs. Directional indicator marks can be attached to the connecting section's outer shell to indicate the direction of the working section's outer shell opening, or directional identification can be achieved through a prominent marking at the tail end.

[0038] The device provided by this invention is not only suitable for endoscopic intervertebral disc manipulation, but also for microscopic or open surgery intervertebral disc manipulation, and can be used in other medical fields such as arthroscopy. By changing the structure of the working part, the blade design, or adjusting the angle, it can be adapted to various surgical scenarios, providing efficient and safe solutions for different clinical needs. This flexibility and adaptability give the device high industrialization value and promotion potential.

[0039] Example 1

[0040] Endoscopic spinal intervertebral space cleaning device

[0041] Structural design: The connecting part is cylindrical, the outer shell of the working part is spherical with a single-sided opening and double serrated blades, and the cutter head has double-sided openings and double serrated blades.

[0042] Applications: Used for endoscopic intervertebral discectomy during spinal surgery. It can clean the nucleus pulposus tissue of the intervertebral disc and simultaneously use the serrated blade of the blade, which extends above the cut surface of the outer sleeve, to efficiently plan and remove the cartilaginous endplate with raised edges and a concave center.

[0043] Materials: Both the outer and inner core rods are made of stainless steel, while the working part is made of high-strength steel.

[0044] Operation: In conjunction with the power system, it achieves precise planing through rotation, and the debris is sucked out through the hollow pipe.

[0045] Example 2

[0046] Joint soft tissue repair device

[0047] Structural design: The connecting part is cylindrical, the outer shell of the working part is an elliptical single-opening beveled semi-circular blade, and the cutting head is a single-opening beveled semi-circular blade.

[0048] Purpose: To remove soft tissue hyperplasia and improve joint function during arthroscopic surgery.

[0049] Materials: Both the outer shell and the cutting head are made of ceramic material to improve wear resistance and cutting ability.

[0050] Operation: Use directional markers to control the direction of the cutting edge to ensure precise dressing.

[0051] Example 3

[0052] Spinal intervertebral disc clearing device

[0053] Structural design: The connecting part is 45° crescent-shaped, the working part shell is spherical with double-sided opening and double serrated blades, and the cutter head has double-sided opening and double serrated blades.

[0054] Applications: Used for opening the annulus fibrosus on one side during spinal surgery. The meniscus-shaped connector allows the working part to extend to the opposite side, enabling treatment of the contralateral intervertebral space. Simultaneously, without changing tools, the two cartilaginous endplates at the proximal and distal ends of the target space can be treated through the double-sided openings of the working part shell.

[0055] Materials: The outer sleeve is made of shape memory alloy, and the blade is made of stainless steel.

[0056] Operation: In conjunction with the power system, the chips are discharged through the tail end suction pipe after grinding.

[0057] Example 4

[0058] Osteoarthritis Fusion Device

[0059] Structural design: The connecting part is crescent-shaped, the outer shell of the working part is cylindrical, and the cutting head is a gravel-shaped grinding head.

[0060] Uses: Used in osteoarthritis surgery to remove bone tissue and promote bone fusion.

[0061] Materials: The outer shell is made of ceramic material, and the blade is made of titanium alloy.

[0062] Operation: Equipped with directional and depth markers, allowing the surgeon to monitor the progress in real time.

[0063] like Figure 3 As shown, the bony endplates of the vertebral bodies are convex at the edges and concave in the middle. Whether performing open or minimally invasive endoscopic intervertebral fusion surgery, it is necessary to manage the intervertebral space, remove the nucleus pulposus, and scrape away the cartilaginous endplates attached to the concave bony endplates to expose the bony endplates, facilitating intervertebral bone grafting and fusion. Minimally invasive endoscopic intervertebral fusion surgery involves less paravertebral muscle dissection, resulting in less trauma and bleeding compared to open surgery. It also allows direct visualization of the nucleus pulposus and cartilaginous endplates within the intervertebral space under endoscopic guidance, ensuring efficient fusion. However, currently, due to the narrow endoscopic scope, only small nucleus pulposus forceps and curettes are used to manage the nucleus pulposus and cartilaginous endplates within the intervertebral space. These instruments need to repeatedly enter and exit around the nerves, leading to low efficiency, long processing time, and a high risk of nerve damage. This requires long-term technical accumulation and significantly increases the workload of the surgeon and the anesthesia time for the patient. The arthroscopic shaving tool, commonly used in sports medicine, can shave soft tissue and simultaneously aspirate to remove tissue debris. However, the thickness and length of the arthroscopic shaver are not compatible with the spinal endoscopy system. More importantly, the arthroscopic shaver is a simple straight cylinder, which can only process the nucleus pulposus tissue in the intervertebral space in the narrow space under endoscopy, and it is difficult to completely remove the cartilaginous endplate with raised edges and a concave center.

[0064] This invention relates to an endoscopic intervertebral disc shaving device, the size and length of which are matched to conventional spinal endoscopes. Unlike traditional sports medicine straight-tube shaving tools, this invention features an enlarged elliptical cutting head and a matching outer sleeve, allowing for easy access to the cartilaginous endplate—with its raised edges and concave center—without much or no movement within the confined space under the endoscope. Red, green, and yellow warning lines are provided to provide real-time monitoring and alerts to the surgeon regarding the depth of insertion, highlighting potentially dangerous depths. The yellow line indicates a depth of 30mm into the intervertebral space, preventing excessive depth cutting and effectively reducing the risk of injury to abdominal organs from the annulus fibrosus during blind surgical manipulation. The red line indicates the opening position of the working section, preventing shallow insertion into the intervertebral space and potential nerve damage from the shaving tool. A 0.1-4mm protective rail is designed at the distal end of the working section to prevent excessive depth cutting into the intervertebral space, which could break through the annulus fibrosus structure and damage adjacent organs. Furthermore, this device, when used in conjunction with an endoscope, simultaneously excises the nucleus pulposus and cartilaginous endplate within the intervertebral space, allowing for real-time observation of the treatment process. The processed tissue debris is then aspirated through a hollow tube, improving efficiency. Applying this invention to treat the intervertebral space allows for a single, endoscopic procedure after insertion, effectively avoiding the risks of nerve disturbance and damage caused by repeated insertion and removal of instruments such as nucleus pulposus forceps and curettes during traditional intervertebral space treatment, thus simplifying the surgery.

[0065] In the description of this utility model, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In addition, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0066] The above description is only a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any modifications, equivalent substitutions and improvements made by those skilled in the art within the technical scope disclosed in this utility model, and within the spirit and principles of this utility model, should be included within the protection scope of this utility model.

Claims

1. An endoscopic intervertebral disc shaving device, characterized in that, The device includes a connecting part, one end of which has a working part, and the other end has a universal connection interface for docking with a power system. The working part includes a housing and a cutter head. The inner diameter of the working part is larger than that of the connecting part, and it is bulging at the distal end. The diameter of the cutter head in the working part is larger than that of the outer sleeve rod in the connecting part. The tip of the housing of the working part has a blunt rounded design and can be fitted with a 0.1mm-4mm protective rail. Both the housing and the cutter head of the working part have openings. The connecting part includes an outer sleeve rod and an inner core rod. A hollow pipe is provided between the inner core rod of the connecting part and the cutter head of the working part, and it is connected to a connector. After the power system is connected to the connector, the inner core rod and the cutter head move and rotate axially within the outer sleeve rod and the housing. The suction function is achieved through the openings in the housing of the working part, the openings in the cutter head, and the hollow pipe between the inner core rod of the connecting part and the cutter head of the working part.

2. The endoscopic intervertebral disc shaving device as described in claim 1, characterized in that, The outer sleeve of the connecting part matches the inner core rod, and is either straight or crescent-shaped at 0-45 degrees.

3. The endoscopic intervertebral disc shaving device as described in claim 1, characterized in that, The outer shell of the working part matches the cutting head of the working part. The outer shell is a distally enlarged structure, and its shape can be spherical, elliptical, cylindrical, or olive-shaped.

4. The endoscopic intervertebral disc shaving device as described in claim 1, characterized in that, The working part housing and the cutting head are single-sided, double-sided, or multi-sided openings, and the cutting edge type is flat, beveled semi-circular, single serrated, or double serrated.

5. The endoscopic intervertebral disc shaving device as described in claim 1, characterized in that, The working head is an open, hollow, bladed structure, or a solid grinding head with a surface shape that matches the outer shell of the working part, such as a watermelon shape or a gravel shape.

6. The endoscopic intervertebral disc shaving device as described in claim 1, characterized in that, A smooth coating can be added between the inner and outer layers.

7. The endoscopic intervertebral disc shaving device as described in claim 1, characterized in that, A dedicated suction pipe can be designed at the outer sleeve of the connecting part.

8. The endoscopic intervertebral disc shaving device as described in claim 1, characterized in that, The device is made of titanium alloy, stainless steel, shape memory alloy, high-strength steel metal materials, or ceramic non-metal materials; the manufacturing process includes casting, laser cutting, thermoforming, welding and precision machining.

9. The endoscopic intervertebral disc shaving device as described in claim 1, characterized in that, The connecting part outer sleeve rod and the working part outer shell are an integral structure or are made into one piece through welding or bonding processes; the connecting part inner core rod and the working part cutter head are an integral structure or are made into one piece through welding or bonding processes.

10. The endoscopic intervertebral disc shaving device as described in claim 1, characterized in that, The working part is 3-30mm long. Red, green and yellow conspicuous lines are set at 10mm, 20mm and 30mm from the tip of the working part to the connecting part. A direction indicator mark is set at the connecting part's outer sleeve to indicate the direction of the opening of the working part's outer shell.

Images