Hollow electrical contact processing device

Abstract

The invention discloses a hollow electric contact processing device, which relates to the technical field of electric contact precious metal material manufacturing, and comprises a mounting assembly and a processing assembly, the installation assembly comprises an installation base, a center cylinder arranged on the installation base, a fixing ring connected with the center cylinder, a fixing cylinder connected with the fixing ring, a sliding cylinder connected to the exterior of the fixing cylinder in a sleeving mode, a handle connected with the sliding cylinder, a limiting rod arranged in the fixing cylinder, a pushing cylinder connected to the interior of the fixing cylinder in a sleeving mode and a chuck. The machining assembly comprises a mounting frame, a motor arranged on the mounting frame and a transmission wheel connected with the motor. By means of the unique linkage design of the handle, the sliding barrel, the limiting rod, the pushing barrel and the clamping head and the slope matching and lever principle, a workpiece can be rapidly clamped and loosened through one hand and one action, operation is visual and labor-saving, the workpiece clamping and replacing time is greatly shortened, and the clamping device is suitable for the machining scene of frequent feeding and discharging.

Description

Technical Field

[0001] This invention relates to the technical field of manufacturing precious metal materials for electrical contacts, and more particularly to a processing apparatus for hollow electrical contacts. Background Technology

[0002] Electrical contacts, as the "heart" of low-voltage electrical appliances, are widely used in temperature control switches, automotive and motorcycle electrical components, and other fields. Electrical contacts are typically made of precious metals such as Ag (silver), AgSnO2 (silver tin oxide), and AgNi (silver nickel), or their composite materials. Currently, the most commonly used riveted electrical contacts in the industry mainly include two types: solid and hollow structures. While the traditional solid riveted electrical contact has a relatively simple manufacturing process, the solid rod portion of the solid contact does not play a major role in conductivity and contact, yet it occupies a large volume of material. This structure results in expensive silver alloy material being wasted in non-functional areas, failing to meet the company's continuous cost reduction needs. Furthermore, when riveting the contact to hardware terminals or springs, the solid rod has high deformation resistance. To induce plastic deformation of the solid rod to form a secure rivet head, the riveting equipment must apply enormous impact force. Excessive riveting force often causes thin springs or terminal substrates to warp, deform, or even crack, severely affecting the dimensional accuracy and electrical operating characteristics stability of the switch assembly. Therefore, in order to solve the problems of high cost, difficult riveting, and heavy weight of solid contacts, the industry is gradually shifting towards hollow riveted electrical contacts, and there is an urgent need to develop a hollow electrical contact processing device for processing electrical contacts. Summary of the Invention

[0003] In order to solve the problems of existing hollow electrical contact processing devices, the present invention proposes a hollow electrical contact processing device, which performs hollow processing on electrical contacts.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A hollow electrical contact processing device includes an installation assembly, comprising a mounting base, a central cylinder disposed on the mounting base, a fixing ring connected to the central cylinder, a fixing cylinder connected to the fixing ring, a sliding cylinder sleeved outside the fixing cylinder, a handle connected to the sliding cylinder, a limiting rod disposed inside the fixing cylinder, a push cylinder sleeved inside the fixing cylinder, and a chuck; a processing assembly, disposed on the mounting base, including a mounting frame, a motor disposed on the mounting frame, a transmission wheel connected to the motor, a fixing frame disposed on the mounting frame, a fixing rod fixedly connected to the fixing frame, a rotating cylinder sleeved on the fixing rod, a gear fixedly connected to the rotating cylinder, a first bevel gear disposed in the middle of the fixing rod, a second bevel gear meshing with the first bevel gear, and an outer cylinder sleeved outside the fixing rod.

[0005] In a preferred embodiment of the hollow electrical contact processing device of the present invention, the central cylinder passes through the mounting base and is fixedly disposed within the mounting base. The end of the central cylinder is connected to the fixing ring by a thread, and the fixing ring is connected to the fixing cylinder by a thread. The end of the fixing cylinder has a trumpet-shaped inner wall, and the side wall of the fixing cylinder has several through holes, which are located on the same vertical plane.

[0006] In a preferred embodiment of the hollow electrical contact processing device of the present invention, the slide cylinder is slidably connected to the fixed cylinder, the slide cylinder has a groove, and the inner wall of the slide cylinder is funnel-shaped; the mounting base is also provided with a universal ball, the universal ball is fixedly connected to the handle, the handle is ring-shaped, and a slider is rotatably provided on the inner wall of the handle, the slider being embedded in the groove.

[0007] In a preferred embodiment of the hollow electrical contact processing device of the present invention, the limiting rod is disposed in the through hole and is slidably disposed, and the end of the limiting rod is provided with an inclined surface; the chuck is sleeved in the fixed cylinder and the end of the chuck is in contact with the inner wall of the fixed cylinder; the push cylinder is sleeved outside the chuck and is disposed between the fixed cylinder and the chuck, and the push cylinder has an inclined surface that is in contact with the limiting rod, and the push cylinder abuts against the chuck.

[0008] In a preferred embodiment of the hollow electrical contact processing device of the present invention, the motor output shaft is fixedly connected to the transmission wheel, and the transmission wheel meshes with a gear; the fixing frame is fixedly installed on the mounting frame, two fixing frames are provided, the fixing rod is arranged between the fixing frames, and the fixing rod is fixedly connected to one fixing frame.

[0009] In a preferred embodiment of the hollow electrical contact processing device of the present invention, the rotating cylinder is rotatably mounted on the fixed rod, the gear is fixedly connected to the end of the rotating cylinder, and a slide bar is provided on the side wall of the rotating cylinder, the slide bar being in a straight line.

[0010] In a preferred embodiment of the hollow electrical contact processing device of the present invention, the first bevel gear is fixedly disposed in the middle of the fixed rod, the second bevel gear is rotatably connected to the rotating cylinder, and a guide groove is formed on the inner wall of the outer cylinder.

[0011] In a preferred embodiment of the hollow electrical contact processing device of the present invention, a lever is also fixedly provided on the back of the second bevel gear, the lever is embedded in the guide groove, and the lever is not located at the center of the second bevel gear.

[0012] In a preferred embodiment of the hollow electrical contact processing device of the present invention, the outer cylinder has a notch, the slide bar is embedded in the notch, and the outer cylinder is slidably connected to the rotating cylinder.

[0013] In a preferred embodiment of the hollow electrical contact processing device of the present invention, one end of the outer cylinder is inserted into the central cylinder, and a drill bit is fixed at the end of the outer cylinder.

[0014] The beneficial effects of this invention are:

[0015] This invention allows the sliding cylinder to move by turning a handle, causing a limiting rod to extend into the fixed cylinder through the inner wall of the sliding cylinder. Utilizing the principle of inclined planes and levers, it enables rapid clamping and releasing of workpieces with a single hand and a single action. The operation is intuitive and labor-saving, greatly reducing workpiece clamping and changeover time, making it suitable for processing scenarios with frequent loading and unloading. The drill bit continuously rotates while automatically reciprocating; when the drill bit moves forward, it drills a hole in the electrical contact, and when it moves backward, it separates from the electrical contact. This dynamic "drill-retreat-drill" machining method is beneficial for chip breaking and removal, effectively preventing chips from clogging deep holes, thereby improving the surface finish of the inner hole, ensuring stable machining dimensions, and reducing drill wear. The machining assembly is driven by a single motor 202, cleverly utilizing the first and second bevel gears and the lever-guide groove mechanism to automatically convert the rotary motion into a composite motion of rotation and axial feed. In the clamping state, the limit rod is locked by the inner wall of the flared opening of the slide cylinder, and the push cylinder generates a continuous clamping force on the chuck, ensuring that the clamping is firm and reliable during the machining process and preventing the workpiece from loosening and affecting accuracy. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the hollow electrical contact processing device of the present invention;

[0017] Figure 2 This is a schematic diagram of the handle structure of the hollow electrical contact processing device of the present invention;

[0018] Figure 3 This is a schematic diagram of the slide cylinder structure of the hollow electrical contact processing device of the present invention;

[0019] Figure 4 This is a schematic diagram of the chuck structure of the hollow electrical contact processing device of the present invention;

[0020] Figure 5 This is a cross-sectional view of the mounting assembly structure of the hollow electrical contact processing device of the present invention;

[0021] Figure 6 This is a schematic diagram of the processing component structure of the hollow electrical contact processing device of the present invention;

[0022] Figure 7 This is a schematic diagram of the rotating cylinder structure of the hollow electrical contact processing device of the present invention;

[0023] Figure 8 This is a schematic diagram of the fixing rod structure of the hollow electrical contact processing device of the present invention;

[0024] Figure 9 This is a schematic diagram of the outer cylinder structure of the hollow electrical contact processing device of the present invention;

[0025] Figure 10 This is a cross-sectional view of the processing component structure of the hollow electrical contact processing device of the present invention;

[0026] Reference numerals: 100, Mounting assembly; 101, Mounting base; 102, Center cylinder; 103, Retaining ring; 104, Retaining cylinder; 1041, Through hole; 105, Sliding cylinder; 1051, Groove; 106, Handle; 1061, Universal ball; 1062, Slider; 107, Limiting rod; 108, Push cylinder; 109, Chuck; 200, Machining assembly; 201, Mounting frame; 202, Motor; 203, Transmission wheel; 204, Fixing frame; 205, Fixing rod; 206, Rotating cylinder; 2061, Sliding bar; 2062, Guide groove; 207, Gear; 208, First bevel gear; 209, Second bevel gear; 2091, Lever; 210, Outer cylinder; 2101, Notch; 2102, Drill bit. Detailed Implementation

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0028] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0029] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0030] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0031] Example 1

[0032] This embodiment provides a hollow electrical contact processing device, referring to... Figure 1 This device includes an installation component 100 and a processing component 200.

[0033] Reference Figures 2-5 The mounting assembly 100 includes a mounting base 101, a central cylinder 102 disposed on the mounting base 101, a fixing ring 103 connected to the central cylinder 102, a fixing cylinder 104 connected to the fixing ring 103, a sliding cylinder 105 sleeved on the fixing cylinder 104, a handle 106 connected to the sliding cylinder 105, a limiting rod 107 disposed inside the fixing cylinder 104, a push cylinder 108 sleeved inside the fixing cylinder 104, and a clamp 109.

[0034] The processing component 200 is disposed on the mounting base 101, as shown in the reference. Figures 6-10 The processing component 200 includes a mounting frame 201, a motor 202 mounted on the mounting frame 201, a transmission wheel 203 connected to the motor 202, a fixing frame 204 mounted on the mounting frame 201, a fixing rod 205 fixedly connected to the fixing frame 204, a rotating cylinder 206 sleeved on the fixing rod 205, a gear 207 fixedly connected to the rotating cylinder 206, a first bevel gear 208 located in the middle of the fixing rod 205, a second bevel gear 209 meshing with the first bevel gear 208, and an outer cylinder 210 sleeved outside the fixing rod 205.

[0035] Among them, such as Figure 5 As shown, the central cylinder 102 penetrates the mounting base 101 and is fixedly installed inside the mounting base 101. The end of the central cylinder 102 is connected to the fixing ring 103 by a thread, and the fixing ring 103 is connected to the fixing cylinder 104 by a thread. The end of the fixing cylinder 104 has a trumpet-shaped inner wall, and a plurality of through holes 1041 are opened on the side wall of the fixing cylinder 104. The through holes 1041 are located on the same vertical plane. The limiting rod 107 is disposed in the through hole 1041 and is slidably disposed. The end of the limiting rod 107 is provided with an inclined surface. The clamp 109 is sleeved in the fixed cylinder 104 and the end of the clamp 109 is in contact with the inner wall of the fixed cylinder 104. The push cylinder 108 is sleeved outside the clamp 109 and is disposed between the fixed cylinder 104 and the clamp 109. The push cylinder 108 has an inclined surface that is in contact with the limiting rod 107 and abuts against the clamp 109.

[0036] like Figures 2-5To allow for easy clamping and fixing of the electrical contacts and their replacement after processing, the electrical contacts are inserted into the chuck 109. To control the clamping and loosening of the chuck 109, the handle 106 can be adjusted. In this embodiment, a manual adjustment method using the handle 106 is provided. A universal ball 1061 is provided at the bottom of the handle 106, embedded in the mounting base 101. The universal ball 1061 can move freely. The bottom of the handle 106 is fixedly connected to the universal ball 1061, and the handle 106 as a whole forms a ring around the slide cylinder 1. 05. A plurality of sliders 1062 are provided on the inner wall of the handle 106. The sliders 1062 are embedded in the grooves 1051 of the slide cylinder 105. The sliders 1062 are rotatably connected to the inner wall of the handle 106. When the handle 106 is turned, the slide cylinder 105 can be pushed to slide on the fixed cylinder 104 through the sliders 1062. Adjusting the handle 106 can directly control the forward and backward movement of the slide cylinder 105. When clamping the electrical contacts, turning the handle 106 causes the slide cylinder 105 to move towards the processing assembly 200. When the slide cylinder 105 moves backward, the slide cylinder 106... The inner wall of the slide cylinder 105 moves synchronously. For the limiting rod 107, which abuts against the inner wall of the slide cylinder 105, the inner wall of the slide cylinder 105 continuously contracts. The inner wall of the slide cylinder 105 causes the limiting rod 107 to extend into the fixed cylinder 104. An inclined surface is provided at the end of the limiting rod 107, which fits against the inclined surface on the push cylinder 108. When the limiting rod 107 contracts into the fixed cylinder 104, the inclined surface drives the push cylinder 108 to move towards the end of the fixed cylinder 104. The push cylinder 108 abuts against the clamp 109. Therefore, when the push cylinder 108... When 08 moves, it will push the chuck 109 to move synchronously, so that the chuck 109 extends outward from the fixed cylinder 104. The fixed cylinder 104 has a flared inner wall at the end. At the same time, the end of the chuck 109 is in contact with the inner wall of the fixed cylinder 104. When the chuck 109 moves outward, the end will be squeezed and contracted by the inner wall of the fixed cylinder 104, thereby clamping the electrical contact in the central cylinder 102. Moving the handle 106 forward can stop the limit rod 107 from being squeezed. Pressing the chuck 109 can reset the chuck 109 and stop clamping the electrical contact.

[0037] For processing the electrical contacts, the output shaft of the motor 202 is fixedly connected to the transmission wheel 203, and the transmission wheel 203 meshes with the gear 207. Two fixing frames 204 are fixedly mounted on the mounting frame 201, and a fixing rod 205 is positioned between the fixing frames 204 and fixedly connected to one of them. The rotating cylinder 206 is rotatably mounted on the fixing rod 205, and the gear 207 is fixedly connected to its end. A sliding strip 2061, which is straight, is provided on the side wall of the rotating cylinder 206. The first bevel gear 208 is fixedly mounted in the middle of the fixing rod 205, and the second bevel gear 209 is rotatably connected to the rotating cylinder 206. A guide groove 2062 is formed on the inner wall of the outer cylinder 210. A lever 2091 is fixedly mounted on the back of the second bevel gear 209. The lever 2091 is embedded in the guide groove 2062, and the lever 2091 is not located at the center of the second bevel gear 209. A notch 2101 is provided on the outer cylinder 210, and the slide bar 2061 is embedded in the notch 2101. The outer cylinder 210 is slidably connected to the rotating cylinder 206. One end of the outer cylinder 210 is inserted into the central cylinder 102, and a drill bit 2102 is fixed to the end of the outer cylinder 210.

[0038] After clamping and fixing the electrical contacts, as Figures 6-10The motor 202 is started, driving the transmission wheel 203 to rotate. The transmission wheel 203 meshes with the gear 207, so the motor 202 can directly transmit power to the gear 207, causing the gear 207 to rotate. The gear 207 is fixedly mounted on the rotating cylinder 206. The rotation of the gear 207 drives the rotating cylinder 206 to rotate synchronously. The rotating cylinder 206 is sleeved on the fixed rod 205, which remains stationary. The first bevel gear 208 on the fixed rod 205 is also fixed. Therefore, when the rotating cylinder 206 rotates, the second bevel gear 209, which is rotated on the rotating cylinder 206, will rotate. The first bevel gear 208 remains stationary. The meshing relationship between the two will cause the second bevel gear 209 to rotate around the first bevel gear 208. A lever 2091 is also provided on the back of the second bevel gear 209. The lever 2091 is embedded in the guide groove 2062 on the inner wall of the outer cylinder 210. When the second bevel gear 209 rotates, the lever 2091... 091 will move synchronously in a circular motion. When lever 2091 moves in a circular motion, it will move the outer cylinder 210 back and forth cyclically through guide groove 2062. A slider 2061 is also provided on the rotating cylinder 206. The notch 2101 on the outer cylinder 210 is connected to the slider 2061. When the rotating cylinder 206 rotates, the slider 2061 will synchronously drive the outer cylinder 210 to rotate. Since the slider 2061 is a straight line, the back and forth movement of the outer cylinder 210 will not cause the outer cylinder 210 to rotate. 10 disengages from the slide bar 2061, thus affecting the rotation of the outer cylinder 210. Therefore, in summary, the motor 202 can make the outer cylinder 210 rotate while also moving back and forth in a cyclic manner. A drill bit 2102 is provided at the end of the outer cylinder 210. The drill bit 2102 extends into the central cylinder 102. The drill bit 2102 rotates continuously while also moving back and forth in a cyclic manner, drilling holes in the electrical contacts as they move forward and separating them as they move backward. After the processing is completed, the clamping of the electrical contacts is released, and the finished product is removed.

[0039] The advantage of this solution lies in the fact that the processing device integrates the clamping mechanism and the compound motion processing mechanism into one unit, achieving a highly efficient, precise, and easy-to-operate processing flow. Through a unique linkage design of handle 106-slide cylinder 105-limiting rod 107-push cylinder 108-clamp 109, utilizing inclined plane cooperation and lever principles, it enables rapid clamping and unclamping of workpieces with a single hand and a single action. The operation is intuitive and labor-saving, greatly shortening the workpiece clamping and changeover time, making it suitable for processing scenarios with frequent loading and unloading; the drill bit 2102 performs automatic reciprocating feed while rotating continuously. This dynamic "drill-retreat-drill" machining method facilitates chip breaking and removal, effectively preventing chips from clogging deep holes, thereby improving the surface finish of the inner hole, ensuring dimensional stability, and reducing wear on the drill bit 2102. The machining assembly 200, driven by a single motor 202, cleverly utilizes the first bevel gear 208, the second bevel gear 209, and the lever 2091-guide groove 2062 mechanism to automatically convert rotational motion into a composite motion of rotation and axial feed. In the clamped state, the limiting rod 107 is locked by the inner wall of the flared opening of the slide cylinder 105, and the push cylinder 108 generates a continuous clamping force on the chuck 109, ensuring a firm and reliable clamping during machining and preventing workpiece loosening that could affect accuracy. This high-precision, high-quality inner hole machining achieved through composite motion allows for precise formation of the required hollow structure with minimal material removal. This directly reduces the amount and weight of precious metal blanks, maximizing cost savings for this core cost element while meeting electrical performance requirements.

[0040] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A hollow electrical contact processing device, characterized in that, include: The mounting assembly (100) includes a mounting base (101), a central cylinder (102) disposed on the mounting base (101), a retaining ring (103) connected to the central cylinder (102), a retaining cylinder (104) connected to the retaining ring (103), a sliding cylinder (105) sleeved outside the retaining cylinder (104), a handle (106) connected to the sliding cylinder (105), a limiting rod (107) disposed inside the retaining cylinder (104), a push cylinder (108) sleeved inside the retaining cylinder (104), and a clamp (109). The processing component (200) is mounted on the mounting base (101) and includes a mounting frame (201), a motor (202) mounted on the mounting frame (201), a transmission wheel (203) connected to the motor (202), a fixed frame (204) mounted on the mounting frame (201), a fixed rod (205) fixedly connected to the fixed frame (204), a rotating cylinder (206) sleeved on the fixed rod (205), a gear (207) fixedly connected to the rotating cylinder (206), a first bevel gear (208) located in the middle of the fixed rod (205), a second bevel gear (209) meshing with the first bevel gear (208), and an outer cylinder (210) sleeved outside the fixed rod (205).

2. The hollow electrical contact processing device as described in claim 1, characterized in that: The central cylinder (102) penetrates the mounting base (101) and is fixedly installed inside the mounting base (101). The end of the central cylinder (102) is connected to the fixing ring (103) by a thread, and the fixing ring (103) is connected to the fixing cylinder (104) by a thread. The end of the fixing cylinder (104) is provided with a trumpet-shaped inner wall, and a plurality of through holes (1041) are provided on the side wall of the fixing cylinder (104). The through holes (1041) are located on the same vertical plane.

3. The hollow electrical contact processing device as described in claim 2, characterized in that: The slide cylinder (105) is slidably connected to the fixed cylinder (104). The slide cylinder (105) has a groove (1051) and the inner wall of the slide cylinder (105) is funnel-shaped. The mounting base (101) is also provided with a universal ball (1061). The universal ball (1061) is fixedly connected to the handle (106). The handle (106) is ring-shaped. The inner wall of the handle (106) is rotatably provided with a slider (1062). The slider (1062) is embedded in the groove (1051).

4. The hollow electrical contact processing device as described in claim 3, characterized in that: The limiting rod (107) is slidably disposed in the through hole (1041), and the end of the limiting rod (107) is provided with an inclined surface; the clamp (109) is sleeved in the fixed cylinder (104), and the end of the clamp (109) is in contact with the inner wall of the fixed cylinder (104); the push cylinder (108) is sleeved outside the clamp (109), and the push cylinder (108) is disposed between the fixed cylinder (104) and the clamp (109), and the push cylinder (108) is provided with an inclined surface that is in contact with the limiting rod (107), and the push cylinder (108) abuts against the clamp (109).

5. The hollow electrical contact processing apparatus as described in claim 4, characterized in that: The output shaft of the motor (202) is fixedly connected to the transmission wheel (203), and the transmission wheel (203) meshes with the gear (207); two fixing brackets (204) are fixedly installed on the mounting bracket (201), and the fixing rod (205) is arranged between the fixing brackets (204), and the fixing rod (205) is fixedly connected to one fixing bracket (204).

6. The hollow electrical contact processing apparatus as described in claim 5, characterized in that: The rotating cylinder (206) is rotatably mounted on the fixed rod (205), and the gear (207) is fixedly connected to the end of the rotating cylinder (206). A linear slide bar (2061) is provided on the side wall of the rotating cylinder (206).

7. The hollow electrical contact processing apparatus as described in claim 6, characterized in that: The first bevel gear (208) is fixedly disposed in the middle of the fixed rod (205), the second bevel gear (209) is rotatably connected to the rotating cylinder (206), and a guide groove (2062) is formed on the inner wall of the outer cylinder (210).

8. The hollow electrical contact processing apparatus as described in claim 7, characterized in that: A lever (2091) is also fixedly provided on the back of the second bevel gear (209). The lever (2091) is embedded in the guide groove (2062) and is not located at the center of the second bevel gear (209).

9. The hollow electrical contact processing apparatus as described in claim 8, characterized in that: The outer cylinder (210) has a notch (2101), the slide bar (2061) is embedded in the notch (2101), and the outer cylinder (210) is slidably connected to the rotating cylinder (206).

10. The hollow electrical contact processing apparatus as described in claim 9, characterized in that: One end of the outer cylinder (210) is inserted into the central cylinder (102), and a drill bit (2102) is fixed at the end of the outer cylinder (210).

Images