Flexible tool clamp for numerical control machining of metal parts

Abstract

The invention discloses a metal piece numerical control machining flexible tool clamp, and relates to the technical field of metal piece numerical control machining equipment, the metal piece numerical control machining flexible tool clamp comprises a driving assembly, the top of the driving assembly is fixedly connected with two clamping assemblies, and the two clamping assemblies are symmetrically arranged. According to the flexible tool clamp for numerical control machining of the metal pieces, the metal pieces with the arc-shaped appearance can be clamped through the first clamping block, the flexible tool clamp is suitable for round and cylindrical workpieces with regular shapes, plane metal pieces such as metal plates and bolts can be clamped through the second clamping block, and in addition, the flexible tool clamp can be used for clamping some irregular metal pieces. The third clamping blocks are used for clamping, when a metal piece is clamped between the two third clamping blocks, the clamping jaw making contact with the metal piece can position the metal piece, the clamping jaw which does not make contact with the metal piece blocks the edge of the metal piece under the elastic effect of the fixing spring, the edge positioning effect can be achieved, and clamping flexibility and stability are improved.

Description

Technical Field

[0001] The invention relates to the technical field of metal parts numerical control processing equipment, in particular to a metal parts numerical control processing flexible tooling fixture. Background Art

[0002] CNC machining of metal parts is an advanced manufacturing technology that uses digital control systems to process metal materials. It plays an important role in the field of mechanical manufacturing. During machining, it is necessary to use pre-compiled CNC programs to control the movement and processing parameters of the machine tool, so that the tool can perform cutting, drilling, boring, grinding and other processing operations on the metal parts, thereby obtaining metal parts with the required shape and dimensional accuracy. During CNC machining of metal parts, they need to be precisely positioned to ensure that the tool is processed according to the preset path. The fixture can provide an accurate positioning reference for the metal parts, limit their degrees of freedom during the machining process, and make the position of the metal parts in the machine tool coordinate system fixed and unique, thereby ensuring the accuracy of the machining dimensions.

[0003] However, in the prior art, in the field of CNC machining of metal parts, traditional tooling and fixtures are often specially designed and manufactured for specific metal parts models or shapes. Therefore, when metal parts of different models or shapes need to be processed, the corresponding fixtures must be replaced, which not only increases the procurement cost of the tooling and fixtures and the difficulty of inventory management, but also each replacement of the fixture requires a lot of time for debugging and installation, which seriously affects the production efficiency. Especially in small-batch and diversified metal parts processing and production, this problem of low efficiency and high cost is more prominent.

[0004] Therefore, we proposed a flexible tooling fixture for CNC machining of metal parts to solve the problems raised above. Summary of the invention

[0005] The object of the present invention is to provide a flexible fixture for CNC machining of metal parts, so as to solve the problem that the traditional fixtures mentioned in the above background technology have a fixed shape and cannot meet the clamping requirements of metal parts of different models.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a flexible tooling fixture for CNC machining of metal parts, comprising a driving component, wherein two clamping components are fixedly connected to the top of the driving component, the two clamping components are symmetrically arranged, and the two clamping components each include a reinforcing block, a positioning groove is provided on the opposite side of the two reinforcing blocks, a sliding groove is provided near the top on the opposite side of the two reinforcing blocks, the inner walls of the two sliding grooves are slidably connected with a tooth plate, the outer surfaces of the two tooth plates are provided with a connecting groove, wherein the inner walls of the two connecting grooves are slidably connected with a first clamping block, the inner walls of the other two connecting grooves are slidably connected with a second clamping block, and the inner walls of the two connecting grooves are slidably connected with a third clamping block.

[0007] Preferably, the driving assembly includes a mounting frame, one side of the mounting frame is fixedly connected to a fixing plate, an inner wall of the fixing plate is rotatably connected to an I-shaped plate, and the other side of the mounting frame is fixedly connected to a limiting plate.

[0008] Preferably, one side of the mounting frame is fixedly connected to a fixing frame, a servo motor is arranged on the top of the fixing frame, and an output shaft of the servo motor is fixedly connected to one side of the I-shaped plate.

[0009] Preferably, a bidirectional screw is fixedly connected to the other side of the I-shaped plate, and one end of the bidirectional screw rotates on the inner wall of the limiting plate.

[0010] Preferably, the outer surface of the bidirectional screw is threadedly connected to two moving blocks, the two moving blocks are symmetrically arranged, and the two moving blocks both slide inside the mounting frame.

[0011] Preferably, a controller is arranged on the outer surface of the mounting frame, and the two reinforcing blocks are respectively fixedly connected to the tops of the two moving blocks, and the two reinforcing blocks are symmetrically arranged.

[0012] Preferably, mounting grooves are provided on the sides of the two reinforcement blocks that are away from each other, support plates are fixedly connected to the inner walls of the two mounting grooves, and forward and reverse motors are provided on the tops of the two support plates.

[0013] Preferably, the output shafts of the two forward and reverse motors are fixedly connected to gears, a rotating groove is opened on one side of the two gears, the inner walls of the two rotating grooves are rotatably connected to rotating blocks, and the two rotating blocks are respectively fixedly installed on the inner walls of the two installation grooves.

[0014] Preferably, the outer surfaces of the two gears are respectively meshed with the bottoms of the two tooth plates, and the gears are used to drive the tooth plates to reciprocate, the tops of the two reinforcement blocks are fixedly connected to support rods, one end of the two support rods is provided with an electric push rod, and one end of the two electric push rods is fixedly connected to an iron block.

[0015] Preferably, one side of each of the first clamp block, the second clamp block and the third clamp block is fixedly connected to a magnetic block, the other side of each of the first clamp blocks is arranged in an arc shape, the other side of each of the second clamp blocks is arranged in a plane, the other side of each of the third clamp blocks is arranged in a claw shape, and a plurality of fixing grooves are provided on the opposite side of each of the third clamp blocks, a fixing spring is provided on the inner wall of each of the fixing grooves, and one end of each of the fixing springs is fixedly connected to a clamping claw.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. When in use, the first clamping block can clamp metal parts with arc-shaped appearance, which is suitable for relatively regular round and cylindrical workpieces, while the second clamping block can clamp flat metal parts, such as metal plates, bolts and other workpieces. In addition, for some irregularly shaped metal parts, the third clamping block is used for clamping. When the metal part is clamped between the two third clamping blocks, the clamping claws in contact with the metal part can position it, and the non-contacting clamping claws are blocked at the edge of the metal part under the elastic action of the fixed spring, which can play the role of edge positioning and improve the flexibility and stability of clamping.

[0018] 2. When in use, the controller is used to control the start of the forward and reverse motors, so that the gear drives the tooth plate to move left and right, and the clamping block is selected. The electric push rod is started to drive the iron block to move forward. Since the magnetic block can generate adsorption force on the iron block, the electric push rod can drive the corresponding clamping block to be transported forward, so that it can pass through the positioning groove to facilitate clamping of the metal part. When replacing the clamping block, it is necessary to start the electric push rod again to shrink it, and pull the clamping block back under the action of magnetic adsorption. When the clamping block is completely separated from the positioning groove, the forward and reverse motors are started to drive the gear and the tooth plate to move, so that the magnetic block can be peeled off from the iron block. The clamping tool has the advantage of flexible replacement of the clamping block according to the shape of the metal part, and has a wider range of applications.

[0019] 3. When in use, the servo motor is started through the controller to make the bidirectional screw rotate synchronously with the rotation of the I-shaped plate. By setting the two moving blocks in the inner groove of the mounting frame, the moving blocks can only move left and right when following the rotation of the bidirectional screw, and cannot rotate. At this time, the movement directions of the two moving blocks are opposite. When the two moving blocks move toward each other, the metal parts are clamped, and when the two moving blocks move in opposite directions, the clamping of the metal parts is released. When processing metal parts, the mounting frame is fixed on the CNC machine tool to ensure the firmness of the clamping. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A first-perspective stereoscopic view of a flexible fixture for numerically controlling metal parts of the present invention;

[0021] Figure 2 A second-angle stereoscopic view of a flexible fixture for numerically controlling metal parts of the present invention;

[0022] Figure 3 It is a partial stereoscopic view from a driving perspective of a flexible fixture for numerically controlling metal parts of the present invention;

[0023] Figure 4 This is a first-angle stereoscopic view of a clamping component portion of a flexible fixture for numerically controlling metal parts of the present invention;

[0024] Figure 5It is a perspective view of the second perspective structure of the clamping component part of a flexible fixture for numerical control machining of metal parts according to the present invention;

[0025] Figure 6 It is a third-angle stereoscopic view of a clamping component part of a flexible fixture for numerically controlling metal parts of the present invention;

[0026] Figure 7 It is a fourth perspective stereogram of a clamping assembly portion of a flexible fixture for numerically controlling metal parts of the present invention;

[0027] Figure 8 It is a stereoscopic diagram of the fifth viewing angle structure of the clamping component part of a flexible tooling fixture for CNC machining of metal parts according to the present invention.

[0028] In the figure:

[0029] 1. Driving assembly; 101. Mounting frame; 102. Fixing plate; 103. I-shaped plate; 104. Fixing frame; 105. Servo motor; 106. Bidirectional screw; 107. Moving block; 108. Limiting plate; 2. Clamping assembly; 201. Reinforcement block; 202. Mounting slot; 203. Slide slot; 204. Support plate; 205. Forward and reverse motor; 206. Gear; 207. Rotating slot; 208. Rotating block; 209. Support rod; 210. Electric push rod; 211. Iron block; 212. Tooth plate; 213. First clamping block; 214. Connecting slot; 215. Second clamping block; 216. Third clamping block; 217. Fixing slot; 218. Fixing spring; 219. Clamping claw; 220. Positioning slot; 221. Magnetic block; 3. Controller. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the implementation regulations described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Example 1: Reference Figure 1-Figure 8As shown, the present invention provides a technical solution: a flexible fixture for CNC machining of metal parts, including a driving component 1, the top of the driving component 1 is fixedly connected to two clamping components 2, the two clamping components 2 are symmetrically arranged, the two clamping components 2 each include a reinforcing block 201, the two reinforcing blocks 201 have positioning grooves 220 on opposite sides, the two reinforcing blocks 201 have sliding grooves 203 near the top on the opposite sides, the inner walls of the two sliding grooves 203 are slidably connected to tooth plates 212, and the outer surfaces of the two tooth plates 212 are provided with There are connecting grooves 214, wherein the inner walls of two connecting grooves 214 are slidably connected with first clamping blocks 213, the inner walls of the other two connecting grooves 214 are slidably connected with second clamping blocks 215, and the inner walls of the two connecting grooves 214 are slidably connected with third clamping blocks 216. The two reinforcing blocks 201 are provided with mounting grooves 202 on the opposite sides, and the inner walls of the two mounting grooves 202 are fixedly connected with supporting plates 204. The tops of the two supporting plates 204 are provided with forward and reverse motors 205, and the output shafts of the two forward and reverse motors 205 are fixedly connected with gears 206. A rotating groove 207 is provided on one side of the two gears 206, and a rotating block 208 is rotatably connected to the inner wall of the two rotating grooves 207. The two rotating blocks 208 are respectively fixedly installed on the inner wall of the two mounting grooves 202. The outer surfaces of the two gears 206 are respectively meshed with the bottom of the two toothed plates 212, and the gears 206 are used to drive the toothed plates 212 to reciprocate. The tops of the two reinforcement blocks 201 are fixedly connected to support rods 209, and one end of the two support rods 209 is provided with electric push rods 210, and one end of the two electric push rods 210 is fixedly connected to the inner wall of the two mounting grooves 202. An iron block 211 is connected, and one side of each of the first clamping block 213, the second clamping block 215 and the third clamping block 216 is fixedly connected with a magnetic block 221, the other side of each first clamping block 213 is arranged in an arc shape, the other side of each second clamping block 215 is arranged in a plane, and the other side of each third clamping block 216 is arranged in a claw shape, and a plurality of fixing grooves 217 are opened on the opposite side of each third clamping block 216, and a fixing spring 218 is arranged on the inner wall of each fixing groove 217, and one end of each fixing spring 218 is fixedly connected with a clamping claw 219.

[0032] In this embodiment, when in use, the clamp is selected according to the appearance of the metal piece to be clamped, that is, a selection is made between the first clamp block 213, the second clamp block 215 and the third clamp block 216. The first clamp block 213 can clamp metal pieces with an arc appearance, which is suitable for round and cylindrical workpieces with relatively regular shapes, while the second clamp block 215 can clamp metal pieces with a flat surface, such as metal plates, bolts and other workpieces. In addition, for some irregularly shaped metal pieces, when clamping by a flat surface and a curved surface is not ideal, the third clamp block 216 can be used for clamping. When the metal piece When clamped between the two third clamping blocks 216, the clamping claw 219 in contact with the metal piece can position it, and the clamping claw 219 not in contact is blocked at the edge of the metal piece under the elastic action of the fixing spring 218, which can play the role of edge positioning, thereby improving the flexibility and stability of clamping. When the first clamping block 213, the second clamping block 215 and the third clamping block 216 need to be replaced, the controller 3 controls the start of the forward and reverse motor 205, so that the output shaft of the forward and reverse motor 205 rotates, thereby driving the gear 206 to rotate. At this time, since the rotating groove 207 is sleeved on the outside of the rotating block 208 and rotates, Therefore, the gear 206 can be prevented from shifting during the rotation process. The gear 206 and the tooth plate 212 are meshed with each other, so that the tooth plate 212 can move left and right when the gear 206 rotates. When the clamp type is selected, the corresponding connection groove 214 and the positioning groove 220 are aligned. The number of rotations of the forward and reverse motor 205 is set by the program. Each rotation should just make the positioning groove 220 correspond to a connection groove 214. Then, the electric push rod 210 is started to drive the iron block 211 to move forward. Since the magnetic block 221 is on the iron block 21 1 can generate adsorption force, then the electric push rod 210 can drive the corresponding clamping block to be transported forward, so that it can pass through the positioning groove 220 to facilitate clamping of the metal part. When replacing the clamping block, it is necessary to start the electric push rod 210 again to shrink it, and pull the clamping block back under the action of magnetic adsorption. When the clamping block is completely separated from the positioning groove 220, the forward and reverse motor 205 is started to drive the gear 206 and the tooth plate 212 to move, so that the magnetic block 221 can be peeled off from the iron block 211. The clamping tool has the advantage of being able to flexibly replace the clamping block according to the shape of the metal part, and has a wider range of applications.

[0033] Embodiment 2: Figure 1-Figure 8As shown, the driving assembly 1 includes a mounting frame 101, one side of the mounting frame 101 is fixedly connected to a fixing plate 102, the inner wall of the fixing plate 102 is rotatably connected to an I-shaped plate 103, the other side of the mounting frame 101 is fixedly connected to a limiting plate 108, one side of the mounting frame 101 is fixedly connected to a fixing frame 104, a servo motor 105 is arranged on the top of the fixing frame 104, the output shaft of the servo motor 105 is fixedly connected to one side of the I-shaped plate 103, the other side of the I-shaped plate 103 is fixedly connected to a bidirectional screw 106, one end of the bidirectional screw 106 rotates on the inner wall of the limiting plate 108, the outer surface of the bidirectional screw 106 is threadedly connected to two moving blocks 107, the two moving blocks 107 are symmetrically arranged, the two moving blocks 107 both slide inside the mounting frame 101, the outer surface of the mounting frame 101 is provided with a controller 3, and two reinforcing blocks 201 are respectively fixedly connected to the tops of the two moving blocks 107, and the two reinforcing blocks 201 are symmetrically arranged.

[0034] In this embodiment, when in use, the controller 3 is electrically connected to the servo motor 105, the forward and reverse motor 205, and the electric push rod 210. The controller 3 controls the servo motor 105 to start and rotate its output shaft, thereby driving the I-shaped plate 103 to rotate inside the fixed plate 102. Since the I-shaped plate 103 and the bidirectional screw 106 are connected, the bidirectional screw 106 will rotate synchronously with the rotation of the I-shaped plate 103. At this time, under the limiting action of the limiting plate 108, the bidirectional screw 106 can keep rotating. In order to ensure the stability, two moving blocks 107 are arranged in the inner groove of the mounting frame 101, so that the moving blocks 107 can only move left and right when following the rotation of the bidirectional screw 106, and cannot rotate. At this time, the movement directions of the two moving blocks 107 are opposite. When the two moving blocks 107 move toward each other, the metal parts are clamped, and when the two moving blocks 107 move in opposite directions, the clamping of the metal parts is released. When the metal parts are processed, the mounting frame 101 is fixed on the CNC machine tool to ensure the firmness of the clamping.

[0035] The method of use and working principle of the device: When in use, the controller 3 is electrically connected to the servo motor 105, the forward and reverse motor 205, and the electric push rod 210. The servo motor 105 is started by the controller 3 to rotate its output shaft, thereby driving the I-shaped plate 103 to rotate inside the fixed plate 102. Since the I-shaped plate 103 and the bidirectional screw 106 are connected, the bidirectional screw 106 will rotate synchronously with the rotation of the I-shaped plate 103. At this time, under the limiting action of the limiting plate 108, the bidirectional screw 106 can maintain the stability of rotation. By arranging the two moving blocks 107 in the inner groove of the mounting frame 101, the moving block 107 can only move left and right when rotating with the bidirectional screw 106, and cannot rotate. When the two moving blocks 107 move toward each other, the metal parts are clamped, and when the two moving blocks 107 move in opposite directions, the clamping of the metal parts is released. When the metal parts are processed, the clamping tool can be fixed on the CNC machine tool by using the mounting frame 101. When in use, the clamp is selected according to the appearance of the metal parts to be clamped, that is, the first clamp block 213, the second clamp block 215 and the third clamp block 216 are selected. Among them, the first clamp block 213 can clamp metal parts with an arc appearance, which is suitable for round and cylindrical workpieces with relatively regular shapes, and the second clamp block 215 can clamp metal parts with a plane, such as metal plates, bolts and other workpieces. In addition, for When it is not ideal to clamp some irregularly shaped metal parts by flat surfaces or curved surfaces, the third clamp block 216 can be used for clamping. When the metal part is clamped between the two third clamp blocks 216, the clamping claw 219 in contact with the metal part can position it, and the non-contacting clamping claw 219 is blocked at the edge of the metal part under the elastic action of the fixing spring 218, which can play a role in edge positioning. When the first clamp block 213, the second clamp block 215 and the third clamp block 216 need to be replaced, the controller 3 controls the start of the forward and reverse motor 205, so that the output shaft of the forward and reverse motor 205 rotates, thereby driving the gear 206 to rotate. At this time, since the rotating groove 207 is rotated on the outside of the rotating block 208, the gear 206 can be prevented from shifting during the rotation process. , through the mutual meshing between the gear 206 and the tooth plate 212, the tooth plate 212 can realize left and right movement when the gear 206 rotates. When the clamp type is selected, the corresponding connection groove 214 and the positioning groove 220 are aligned. The number of rotations of the forward and reverse motor 205 is set by the program. Each rotation should just make the positioning groove 220 correspond to a connection groove 214. Then, by starting the electric push rod 210, it drives the iron block 211 to move forward. Since the magnetic block 221 can generate an adsorption force on the iron block 211, the electric push rod 210 can drive the corresponding clamping block to be transported forward so that it can pass through the positioning groove 220 to clamp the metal part. When replacing the clamping block, it is necessary to start the electric push rod 210 again.The clamping block is pulled back under the action of magnetic attraction to make it shrink. When the clamping block is completely separated from the positioning groove 220, the forward and reverse motor 205 is started to drive the gear 206 and the tooth plate 212 to move, so that the magnetic block 221 can be peeled off from the iron block 211.

[0036] The wiring diagram of the servo motor 105, the forward and reverse motor 205, the electric push rod 210 and the controller 3 in the present invention is common knowledge in the field, and its working principle is a well-known technology. The model is selected according to the actual use, so the control method and wiring layout of the servo motor 105, the forward and reverse motor 205, the electric push rod 210 and the controller 3 will not be explained in detail.

[0037] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A flexible fixture for CNC machining of metal parts, comprising a drive assembly (1), the top of which is fixedly connected to two clamping assemblies (2), the two clamping assemblies (2) being symmetrically arranged, and characterized in that: The two clamping assemblies (2) each include a reinforcing block (201), a positioning groove (220) is provided on the opposite side of the two reinforcing blocks (201), a sliding groove (203) is provided near the top on the opposite side of the two reinforcing blocks (201), the inner walls of the two sliding grooves (203) are slidably connected to a tooth plate (212), the outer surfaces of the two tooth plates (212) are provided with a connecting groove (214), wherein the inner walls of the two connecting grooves (214) are slidably connected to a first clamping block (213), the inner walls of the other two connecting grooves (214) are slidably connected to a second clamping block (215), and the inner walls of the other two connecting grooves (214) are slidably connected to a third clamping block (216).

2. The flexible fixture for CNC machining of metal parts according to claim 1 is characterized in that: The driving assembly (1) comprises a mounting frame (101), one side of the mounting frame (101) is fixedly connected to a fixing plate (102), the inner wall of the fixing plate (102) is rotatably connected to an I-shaped plate (103), and the other side of the mounting frame (101) is fixedly connected to a limiting plate (108).

3. The flexible fixture for CNC machining of metal parts according to claim 2 is characterized in that: A fixing frame (104) is fixedly connected to one side of the mounting frame (101), a servo motor (105) is arranged on the top of the fixing frame (104), and an output shaft of the servo motor (105) is fixedly connected to one side of the I-shaped plate (103).

4. The flexible fixture for CNC machining of metal parts according to claim 3 is characterized in that: A bidirectional screw rod (106) is fixedly connected to the other side of the I-shaped plate (103), and one end of the bidirectional screw rod (106) rotates on the inner wall of the limiting plate (108).

5. The flexible fixture for CNC machining of metal parts according to claim 4, characterized in that: The outer surface of the bidirectional screw (106) is threadedly connected to two moving blocks (107), the two moving blocks (107) are symmetrically arranged, and both of the two moving blocks (107) slide inside the mounting frame (101).

6. The flexible fixture for CNC machining of metal parts according to claim 5, characterized in that: A controller (3) is arranged on the outer surface of the mounting frame (101), and the two reinforcing blocks (201) are respectively fixedly connected to the tops of the two moving blocks (107), and the two reinforcing blocks (201) are symmetrically arranged.

7. The flexible fixture for CNC machining of metal parts according to claim 6, characterized in that: The two reinforcement blocks (201) are each provided with a mounting groove (202) on one side away from the other, the inner walls of the two mounting grooves (202) are each fixedly connected with a support plate (204), and the tops of the two support plates (204) are each provided with a forward and reverse motor (205).

8. The flexible fixture for CNC machining of metal parts according to claim 7, characterized in that: The output shafts of the two forward and reverse motors (205) are fixedly connected to gears (206), one side of the two gears (206) is provided with a rotation groove (207), the inner walls of the two rotation grooves (207) are rotatably connected to rotation blocks (208), and the two rotation blocks (208) are respectively fixedly installed on the inner walls of the two installation grooves (202).

9. The flexible fixture for CNC machining of metal parts according to claim 8, characterized in that: The outer surfaces of the two gears (206) are respectively meshed with the bottoms of the two toothed plates (212), and the gears (206) are used to drive the toothed plates (212) to reciprocate. The tops of the two reinforcement blocks (201) are fixedly connected with support rods (209), one end of the two support rods (209) is provided with electric push rods (210), and one end of the two electric push rods (210) is fixedly connected with iron blocks (211).

10. The flexible fixture for CNC machining of metal parts according to claim 9, characterized in that: One side of each of the first clamping block (213), the second clamping block (215) and the third clamping block (216) is fixedly connected to a magnetic block (221); the other side of each of the first clamping blocks (213) is arranged in an arc shape; the other side of each of the second clamping blocks (215) is arranged in a plane shape; the other side of each of the third clamping blocks (216) is arranged in a claw shape; a plurality of fixing grooves (217) are provided on the opposite side of each of the third clamping blocks (216); a fixing spring (218) is provided on the inner wall of each of the fixing grooves (217); and one end of each of the fixing springs (218) is fixedly connected to a clamping claw (219).

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