Positioning tool for CNC machining of arc-shaped shell

Abstract

The utility model discloses a positioning tool for CNC machining of an arc-shaped shell. The device comprises a base, a movable positioning plate, a first positioning mechanism, a second positioning mechanism and a first supporting assembly, wherein the movable positioning plate is arranged on the base in a front-back moving mode and is used for positioning an arc-shaped shell; the first positioning mechanism is used for positioning a first arc-shaped end at the left end of the arc-shaped shell; the second positioning mechanism is used for positioning a second arc-shaped end at the right end of the arc-shaped shell; the first pressing assembly is used for pressing the upper surface of the arc-shaped shell, the first limiting module is used for limiting the front side of the arc-shaped shell, and the second limiting module is used for limiting the rear side of the arc-shaped shell. The fixture can be used for positioning the front and rear sides, the left and right sides and the upper and lower surfaces of the arc-shaped shell in six directions, is accurate in positioning, and can ensure the machining precision of the arc-shaped shell.

Description

[Technical Field]

[0001] This utility model belongs to the field of clamping tooling technology, and in particular relates to a positioning tooling for CNC machining of arc-shaped shells. [Background Technology]

[0002] When machining the curved outer shell of medical testing equipment, it is usually necessary to use fixtures for precise fixation before the CNC center can perform accurate machining. Because the curved outer shell of medical testing equipment has an irregular overall structure, with semi-circular curved surfaces on both sides of different widths, and the front and rear contours are also curved, the CNC center needs to drill and mill the interior of the curved shell. If existing conventional fixing devices are used, they cannot effectively position the curved shell on all four sides.

[0003] In the prior art, there are jigs designed and manufactured for curved shells. For example, Chinese Patent Publication No. CN209425039U discloses a jig for fixing the processing of a robotic arm shell. When using this jig, the first curved connecting end is first placed on the pressing part of the positioning block, and then the side of the second curved connecting end is abutted against the first limiting block of the first limiting mechanism to achieve positioning. The second limiting mechanism cooperates with the positioning block to limit the first curved connecting end, and the second limiting mechanism and the first limiting mechanism cooperate to limit the second curved connecting end. By controlling the telescopic cylinder, the pressing mechanism can further press the side of the robotic arm shell. When machining the curved outer shell of medical testing equipment, the fixture in this solution cannot be used. On the one hand, while this solution clamps and limits the outer periphery of the robotic arm shell, restricting its horizontal movement, it does not limit its vertical movement. When machining one end of the robotic arm shell, the other end may sway upwards, reducing machining accuracy. On the other hand, the bottom surface of the robotic arm shell is flat, allowing it to be directly positioned onto the base plate. However, the curved outer shell of the medical testing equipment has a curved structure on the corresponding side, making it impossible to directly position it onto the base plate. Therefore, the above solution cannot be used to position the curved outer shell of the medical testing equipment.

[0004] Therefore, it is necessary to provide a positioning fixture for CNC machining of curved shells to solve the above-mentioned technical problems. [Utility Model Content]

[0005] The main purpose of this utility model is to provide a positioning fixture for CNC machining of arc-shaped shells, which can be used to complete the positioning of the arc-shaped shells in six directions: front and back sides, left and right sides, and upper and lower surfaces. The positioning is accurate and can ensure the precision of the machining of the arc-shaped shells.

[0006] This utility model achieves the above-mentioned objective through the following technical solution: a positioning fixture for CNC machining of an arc-shaped shell, comprising a base, a movable positioning plate movably disposed on the base for positioning the arc-shaped shell, a first positioning mechanism for positioning the first arc-shaped end on the left side of the arc-shaped shell, a second positioning mechanism for positioning the second arc-shaped end on the right side of the arc-shaped shell, a first support component for supporting the lower surface of the arc-shaped shell, a first pressing component for pressing the upper surface of the arc-shaped shell, a first limiting module for limiting the front side of the arc-shaped shell, and a second limiting module for limiting the rear side of the arc-shaped shell.

[0007] Furthermore, the movable positioning plate is provided with a plurality of first positioning blocks on the front side of the positioning arc-shaped shell and a plurality of second positioning blocks on the rear side of the positioning arc-shaped shell. The positions of the plurality of first positioning blocks are arranged to conform to the contour of the front side of the arc-shaped shell, and the positions of the plurality of second positioning blocks are arranged to conform to the contour of the rear side of the arc-shaped shell. The first positioning blocks and the second positioning blocks are arranged opposite each other and together support the front and rear sides of the arc-shaped shell.

[0008] Both the first positioning block and the second positioning block include a support surface that supports the bottom surface of the arc-shaped shell and a limiting surface that limits the side of the arc-shaped shell.

[0009] Furthermore, the first positioning mechanism includes a first positioning component for positioning the arc surface of the first arc end, a second support component for supporting the lower surface of the first arc end, and a second pressing component for pressing against the upper surface of the first arc end. The first positioning component is provided with a first arc-shaped positioning groove that conforms to the arc surface of the first arc end.

[0010] Furthermore, the second positioning mechanism includes a second positioning member for positioning the arc surface of the second arc end, a third support component for supporting the lower surface of the second arc end, and a third pressing component for pressing against the upper surface of the second arc end. The second positioning member is provided with a second arc-shaped positioning groove that conforms to the arc surface of the second arc end.

[0011] Furthermore, an arc-shaped positioning block is provided in the second arc-shaped positioning groove, and the arc-shaped positioning block is elastically floating on the second positioning member by a first spring.

[0012] Furthermore, the first support assembly, the second support assembly, and the third support assembly all include a cylinder and a support member that is driven by the cylinder to move up and down.

[0013] Furthermore, the first clamping assembly includes a hinge seat disposed on the front side of the movable positioning plate, a swing rod hinged to the hinge seat, a drive handle hinged to the hinge seat and driving the swing rod to swing in the front-back direction, and a first clamping member disposed on the swing rod and pressed against the upper surface of the arc-shaped housing.

[0014] Furthermore, the second clamping assembly includes a first swing arm rotatably disposed at one end of the first positioning member and a second clamping member disposed at the other end of the first swing arm and pressed against the upper surface of the arc-shaped housing;

[0015] The third clamping assembly includes a second swing arm with one end rotatably disposed on the upper end of the second positioning member, and a third clamping member disposed on the other end of the second swing arm and pressed against the upper surface of the arc-shaped housing.

[0016] Furthermore, the first limiting module includes a first limiting component and a second limiting component pressed against the front side of the arc-shaped shell. The first limiting component includes a support crossbar extending in the front-rear direction and a roller rotatably disposed on the support crossbar and pressed against the front side of the arc-shaped shell.

[0017] The second limiting component includes a mounting bracket disposed on the base and a limiting block disposed on the mounting bracket. The limiting block is elastically floating on the mounting bracket by a second spring, and a third arc-shaped positioning groove is provided on the limiting block.

[0018] Furthermore, the second limiting module includes a limiting seat and a limiting rod that is movably disposed within the limiting seat. The limiting rod is elastically floating within the limiting seat via a third spring. The movable positioning plate is provided with an avoidance opening to avoid the limiting seat.

[0019] Compared with the prior art, the beneficial effects of this utility model's positioning fixture for CNC machining of arc-shaped shells are as follows: the movable positioning plate is movably mounted on the base. When the movable positioning plate, on which the arc-shaped shell is placed, is pushed forward, the arc-shaped ends at the left and right ends of the arc-shaped shell can respectively extend into the first positioning mechanism and the second positioning mechanism for contour-following positioning. Moreover, the second positioning mechanism is equipped with an elastically floating arc-shaped positioning block, which ensures that even if the arc-shaped shell undergoes local deformation, the arc-shaped positioning block can still make contour-following contact with the arc-shaped shell for positioning. The cooperation between the first positioning component and the second positioning component can limit the lateral movement of the arc-shaped shell, preventing the arc-shaped shell from deforming. The shell moves in the left and right direction. The second support component and the second pressing component are arranged vertically opposite each other, the first support component and the first pressing component are arranged vertically opposite each other, and the third support component and the third pressing component are arranged vertically opposite each other. The shell is pressed and positioned vertically at the left, middle and right positions, which can prevent the shell from moving vertically and ensure positioning accuracy. The first limit module and the second limit module cooperate with each other to restrict the movement of the shell in the front and back direction. Therefore, the shell can be positioned in six directions: front and back, left and right sides and top and bottom surfaces. The positioning is accurate and can ensure the processing accuracy of the shell. [Attached Image Description]

[0020] Figure 1 This is a top view of the clamping fixture for CNC machining of the arc-shaped shell according to an embodiment of the present invention;

[0021] Figure 2 This is a three-dimensional structural diagram of a clamping fixture for CNC machining of an arc-shaped shell according to an embodiment of the present invention;

[0022] Figure 3 This is a three-dimensional structural diagram of the first positioning mechanism according to an embodiment of the present utility model;

[0023] Figure 4 This is a three-dimensional structural diagram of the second positioning mechanism according to an embodiment of the present utility model;

[0024] Figure 5 This is a three-dimensional structural diagram of a clamping fixture for CNC machining of an arc-shaped shell according to an embodiment of the present invention;

[0025] The numbers in the diagram represent:

[0026] 100 - Clamping fixture for CNC machining of arc-shaped shell; 200 - Arc-shaped shell, 201 - First arc-shaped end, 202 - Second arc-shaped end;

[0027] 1-Base, 11-Slide rail, 12-Slider;

[0028] 2-Moveable positioning plate, 21-First positioning block, 22-Second positioning block, 23-Supporting surface, 24-Limiting surface, 25-Avoidance opening;

[0029] 3-First positioning mechanism, 31-Second support assembly, 311-Support frame, 32-Second clamping assembly, 321-First swing arm, 322-Second clamping element, 33-First positioning element, 331-First arc-shaped positioning groove;

[0030] 4-Second positioning mechanism, 41-Third support assembly, 42-Third clamping assembly, 421-Second swing arm, 422-Third clamping component, 43-Second positioning component, 431-Second arc-shaped positioning groove, 432-Arc-shaped positioning block;

[0031] 5-First support assembly, 51-Cylinder, 52-Support component;

[0032] 6-First clamping assembly, 61-Hinge seat, 62-Swing rod, 63-Drive handle, 64-First clamping element;

[0033] 7-First limiting module, 71-First limiting component, 711-Support crossbar, 712-Roller, 72-Second limiting component, 721-Mounting bracket, 722-Limiting block, 723-Third arc-shaped positioning groove;

[0034] 8-Second limit module, 81-Limit seat, 82-Limit rod.

Detailed Implementation Methods

[0035] Please refer to Figures 1-5 This embodiment is a positioning fixture 100 for CNC machining of an arc-shaped shell. The positioning fixture 100 for CNC machining of an arc-shaped shell includes a base 1, a movable positioning plate 2 that is movably disposed on the base 1 and positions the arc-shaped shell 200, a first positioning mechanism 3 that positions the first arc-shaped end 201 on the left side of the arc-shaped shell 200, a second positioning mechanism 4 that positions the second arc-shaped end 202 on the right side of the arc-shaped shell 200, a first support component 5 that supports the lower surface of the arc-shaped shell 200, a first pressing component 6 that presses the upper surface of the arc-shaped shell 200, a first limiting module 7 that limits the front side of the arc-shaped shell 200, and a second limiting module 8 that limits the rear side of the arc-shaped shell 200.

[0036] A pair of sliding rails 11 extending forward and backward are provided on the base 1, and the movable positioning plate 2 is movably mounted on the base 1 via a slider 12. The movable positioning plate 2 is located in the middle of the base 1, and the first positioning mechanism 3 and the second positioning mechanism 4 are located on the base 1 and are respectively located at the left and right ends of the movable positioning plate 2.

[0037] The movable positioning plate 2 is provided with a plurality of first positioning blocks 21 on the front side of the positioning arc-shaped outer shell 200 and a plurality of second positioning blocks 22 on the rear side of the positioning arc-shaped outer shell 200. The positions of the plurality of first positioning blocks 21 are arranged to conform to the contour of the front side of the arc-shaped outer shell 200, and the positions of the plurality of second positioning blocks 22 are arranged to conform to the contour of the rear side of the arc-shaped outer shell 200. The first positioning blocks 21 and the second positioning blocks 22 are arranged opposite to each other and together support the front and rear sides of the arc-shaped outer shell 200. The first positioning blocks 21 and the second positioning blocks 22 each include a support surface 23 for supporting the bottom surface of the arc-shaped outer shell 200 and a limiting surface 24 for limiting the side of the arc-shaped outer shell 200. The support surface 23 and the limiting surface 24 are perpendicular to each other. When the arc-shaped outer shell 200 is placed on the movable positioning plate 2, the front side of the arc-shaped outer shell 200 is supported on several first positioning blocks 21, and the rear side of the arc-shaped outer shell 200 is supported on several second positioning blocks 22. The support surfaces 23 of the first positioning blocks 21 and the second positioning blocks 22 both support the bottom surface of the arc-shaped outer shell 200. The limiting surface 24 of the first positioning block 21 restricts the arc-shaped outer shell 200 from moving forward. At the same time, the limiting surface 24 of the second positioning block 22 restricts the arc-shaped outer shell 200 from moving backward. Therefore, the first positioning blocks 21 and the second positioning blocks 22 provided on the movable positioning plate 2 can restrict the forward and backward movement of the arc-shaped outer shell 200.

[0038] The first positioning mechanism 3 includes a first positioning member 33 for positioning the arc surface of the first arc end 201, a second support component 31 for supporting the lower surface of the first arc end 201, and a second pressing component 32 for pressing the upper surface of the first arc end 201. The first positioning member 33 is provided with a first arc-shaped positioning groove 331 that conforms to the arc surface of the first arc end 201.

[0039] The second positioning mechanism 4 includes a second positioning member 43 for positioning the arc surface of the second arc end 202, a third support component 41 supported on the lower surface of the second arc end 202, and a third pressing component 42 pressed against the upper surface of the second arc end 202. The second positioning member 43 is provided with a second arc-shaped positioning groove 431 that conforms to the arc surface of the second arc end 202. The first arc-shaped positioning groove 331 and the second arc-shaped positioning groove 431 are arranged opposite each other to each other, respectively positioning the arc surfaces at the left and right ends of the arc shell 200.

[0040] In order to more accurately position the arc-shaped outer shell 200, an arc-shaped positioning block 432 is provided in the second arc-shaped positioning groove 431. The arc-shaped positioning block 432 is elastically floating on the second positioning member 43 by the first spring. The arc-shaped positioning block 432 can elastically float left and right. Even if the arc-shaped outer shell 200 has local deformation, it can still ensure that the arc-shaped positioning block 432 makes conformal contact with the arc-shaped outer shell 200 for positioning. Thus, the cooperation between the first positioning member 33 and the second positioning member 43 can limit the arc-shaped outer shell 200 in the left and right directions and prevent the arc-shaped outer shell 200 from moving in the left and right directions.

[0041] The second support component 31, the first support component 5, and the third support component 41 are arranged from left to right and conform to the contour of the arc-shaped outer shell 200. In this embodiment, the second support component 31, the first support component 5, and the third support component 41 are distributed from left to right with a staggered front-to-back arrangement, respectively supporting the left, middle, and right parts of the lower surface of the arc-shaped outer shell 200, ensuring stable support. The second clamping component 32 and the third clamping component 42 are arranged opposite each other from left to right and conform to the contour of the arc-shaped outer shell 200. In this embodiment, the second clamping component 32, the first clamping component 6, and the third clamping component 42 are distributed from left to right with a staggered front-to-back arrangement, respectively clamping the left, middle, and right parts of the upper surface of the arc-shaped outer shell 200, ensuring stable clamping. The second support component 31 and the second pressing component 32 are arranged vertically opposite each other, the first support component 5 and the first pressing component 6 are arranged vertically opposite each other, and the third support component 41 and the third pressing component 42 are arranged vertically opposite each other. They are pressed and positioned vertically at the left, middle and right positions of the arc-shaped outer shell 200, which can prevent the arc-shaped outer shell 200 from moving in the vertical direction and ensure the positioning accuracy.

[0042] The first support assembly 5, the second support assembly 31, and the third support assembly 41 all include a cylinder 51 and support members 52 that are driven by the cylinder 51 to move up and down. Since the width of the first arc-shaped end 201 is relatively wide, to ensure the stability of the support, the second support assembly 31 is provided with two support members 52. The two support members 52 are jointly mounted on a support frame 311. When the cylinder 51 drives the support frame 311 to move up and down, it can drive the two support members 52 to move up and down. In other embodiments, the number of support members 52 is set according to the width of the arc-shaped outer shell 200, and is not limited here.

[0043] The first pressing assembly 6 includes a hinge seat 61 disposed on the front side of the movable positioning plate 2, a swing rod 62 hinged to the hinge seat 61, a drive handle 63 hinged to the hinge seat 61 and driving the swing rod 62 to swing in the front-back direction, and a first pressing member 64 disposed on the swing rod 62 and pressed against the upper surface of the arc-shaped housing 200. The first pressing member 64 is a pressing wheel or a pressing plate, which is not limited here.

[0044] The second clamping assembly 32 includes a first swing arm 321 rotatably mounted on the upper end of the first positioning member 33 at one end, and a second clamping member 322 mounted on the other end of the first swing arm 321 and pressed against the upper surface of the arc-shaped housing 200; the third clamping assembly 42 includes a second swing arm 421 rotatably mounted on the upper end of the second positioning member 43 at one end, and a third clamping member 422 mounted on the other end of the second swing arm 421 and pressed against the upper surface of the arc-shaped housing 200. Since the width of the first arc-shaped end 201 is relatively wide, to ensure clamping stability, the second clamping member 322 can be configured as a clamping plate, and the length of the clamping plate can be adjusted according to the width of the first arc-shaped end 201. The structure of the third clamping member 422 can be configured to be consistent with the structure of the support member 52, or it can be configured as a clamping plate, which can be adjusted according to the actual situation and is not limited here.

[0045] The first limiting module 7 and the second limiting module 8 cooperate with each other to restrict the movement of the arc-shaped outer shell 200 in the front-back direction. The first limiting module 7 includes a first limiting component 71 and a second limiting component 72 pressed against the front side of the arc-shaped outer shell 200. The first limiting component 71 includes a support crossbar 711 disposed on the hinge seat 61 and extending in the front-back direction, and a roller 712 rotatably disposed on the support crossbar 711 and pressed against the front side of the arc-shaped outer shell 200. Since it is necessary to machine a hole on the front side of the second arc-shaped end 202, in order to ensure the stability of the positioning, a second limiting component 72 is provided at the second arc-shaped end 202 on the front side of the arc-shaped outer shell 200 to further limit the front side of the arc-shaped outer shell 200 and prevent the arc-shaped outer shell 200 from moving forward. The second limiting component 72 includes a mounting bracket 721 provided on the base 1 and a limiting block 722 provided on the mounting bracket 721. The limiting block 722 is elastically floating on the mounting bracket 721 by a second spring. A third arc-shaped positioning groove 723 is provided on the limiting block 722, and the third arc-shaped positioning groove 723 is positioned opposite to the second arc-shaped positioning groove 431.

[0046] The second limiting module 8 includes a limiting seat 81 and a limiting rod 82 that is movably disposed within the limiting seat 81. The limiting rod 82 is elastically floating within the limiting seat 81 via a third spring. The limiting seat 81 is directly disposed on the cylinder 51 of the first support component 5 or on the base 1. Correspondingly, the movable positioning plate 2 is provided with an avoidance opening 25 to avoid the limiting seat 81.

[0047] When using the positioning fixture 100 for CNC machining of an arc-shaped shell provided in this solution, the arc-shaped shell 200 is placed on the movable positioning plate 2. The front side of the arc-shaped shell 200 is supported on several first positioning blocks 21, and the rear side of the arc-shaped shell 200 is supported on several second positioning blocks 22. The support surfaces 23 of the first positioning blocks 21 and the second positioning blocks 22 both support the bottom surface of the arc-shaped shell 200. The limiting surface 24 of the first positioning block 21 restricts the arc-shaped shell 200 from moving forward, while the limiting surface 24 of the second positioning blocks 22 restricts the arc-shaped shell 200 from moving backward. The first positioning blocks 21 and the second positioning blocks 22 provided on the movable positioning plate 2 can restrict the arc-shaped shell 200 from moving backward. The arc-shaped outer shell 200 moves back and forth. The moving positioning plate 2 is manually pushed forward. The arc surface of the first arc-shaped end 201 conforms to the first arc-shaped positioning groove 331, and the arc surface of the second arc-shaped end 202 conforms to the second arc-shaped positioning groove 431. The arc-shaped positioning block 432 can elastically float left and right, ensuring that the arc-shaped positioning block 432 makes conformal contact with the arc-shaped outer shell 200 for positioning. During the forward movement of the moving positioning plate 2, it presses against the limiting rod 82. At this time, the third spring is compressed. When the moving positioning plate 2 moves forward to its designated position, the third spring extends, causing the limiting rod 82 to rise. The limiting rod 82 is positioned at the rear of the arc-shaped outer shell 200. Positioning is performed on the rear side of the arc-shaped outer shell 200. The roller 712 of the first limiting component 71 abuts against the front side of the arc-shaped outer shell 200. At the same time, the limiting block 722 of the second limiting component 72 also abuts against the front side of the arc-shaped outer shell 200, completing the positioning of the front and rear sides of the arc-shaped outer shell 200. The arc surface of the first arc-shaped end 201 is positioned in a contour fit with the first arc-shaped positioning groove 331, and the arc surface of the second arc-shaped end 202 is positioned in a contour fit with the second arc-shaped positioning groove 431, completing the positioning of the left and right ends of the arc-shaped outer shell 200. The second support component 31, the first support component 5, and the third support component 41 all start working. The cylinder 51 drives the support component 52 to support the lower part of the arc-shaped outer shell 200. On the surface, the second clamping assembly 32, the first clamping assembly 6, and the third clamping assembly 42 begin to work. The first swing arm 321 is manually rotated to press the second clamping member 322 against the upper surface of the first arc-shaped end 201. The second swing arm 421 is manually rotated to press the third clamping member 422 against the upper surface of the second arc-shaped end 202. The drive handle 63 is rotated to drive the swing rod 63 to rotate backward, so that the first clamping member 64 is pressed against the upper surface of the arc-shaped shell 200, completing the positioning of the upper and lower surfaces of the arc-shaped shell 200. At this time, the positioning of the arc-shaped shell 200 is completed in six directions: front and rear sides, left and right sides, and upper and lower surfaces. The positioning is accurate and can ensure the processing accuracy of the arc-shaped shell 200.

[0048] The above descriptions are merely some embodiments of this utility model. For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of this utility model, and all such modifications and improvements fall within the protection scope of this utility model.

Claims

1. A positioning tool for arc-shaped shell CNC machining, characterized in that: It includes base, mobile positioning plate which is movably arranged on the base and positions arc-shaped shell, first positioning mechanism which positions first arc-shaped end of left end of arc-shaped shell, second positioning mechanism which positions second arc-shaped end of right end of arc-shaped shell, first supporting assembly which supports lower surface of arc-shaped shell, first pressing assembly which presses upper surface of arc-shaped shell, first limiting module which limits front side of arc-shaped shell and second limiting module which limits rear side of arc-shaped shell.

2. The positioning tool for arc-shaped shell CNC machining according to claim 1, characterized in that: The mobile positioning plate is provided with a plurality of first positioning blocks which position front side of arc-shaped shell and a plurality of second positioning blocks which position rear side of arc-shaped shell, the position distribution of the plurality of first positioning blocks is profiled with front side of arc-shaped shell, the position distribution of the plurality of second positioning blocks is profiled with rear side of arc-shaped shell, the first positioning blocks and the second positioning blocks are oppositely arranged and jointly support front and rear sides of arc-shaped shell; The first positioning blocks and the second positioning blocks both include supporting surface which supports bottom surface of arc-shaped shell and limiting surface which limits side edge of arc-shaped shell.

3. The positioning tool for arc-shaped shell CNC machining according to claim 1, characterized in that: The first positioning mechanism includes first positioning piece which positions arc surface of first arc-shaped end, second supporting assembly which supports lower surface of first arc-shaped end and second pressing assembly which presses upper surface of first arc-shaped end, the first positioning piece is provided with first arc-shaped positioning groove which profiledly cooperates with arc surface of first arc-shaped end.

4. The positioning tool for arc-shaped shell CNC machining according to claim 3, characterized in that: The second positioning mechanism includes second positioning piece which positions arc surface of second arc-shaped end, third supporting assembly which supports lower surface of second arc-shaped end and third pressing assembly which presses upper surface of second arc-shaped end, the second positioning piece is provided with second arc-shaped positioning groove which profiledly cooperates with arc surface of second arc-shaped end.

5. The positioning tool for CNC machining of an arc-shaped shell according to claim 4, characterized in that: The second arc-shaped positioning groove is provided with arc-shaped positioning block, the arc-shaped positioning block is elastically and floatingly arranged on the second positioning piece by first spring.

6. The positioning tool for CNC machining of an arc-shaped shell according to claim 4, characterized in that: The first supporting assembly, the second supporting assembly and the third supporting assembly all include air cylinder and supporting piece which is driven by the air cylinder to move up and down.

7. The positioning tool for CNC machining of an arc-shaped shell according to claim 1, characterized in that: The first pressing assembly includes hinged seat which is arranged on front side of the mobile positioning plate, swing rod which is hinged on the hinged seat, driving handle which is hinged on the hinged seat and drives the swing rod to swing in front and rear directions and first pressing piece which is arranged on the swing rod and presses on upper surface of arc-shaped shell.

8. The positioning tool for CNC machining of an arc-shaped shell according to claim 4, characterized in that: The second pressing assembly includes first swing arm which is rotatably arranged on upper end of the first positioning piece and second pressing piece which is arranged on other end of the first swing arm and presses on upper surface of arc-shaped shell. The third pressing assembly includes second swing arm which is rotatably arranged on upper end of the second positioning piece and third pressing piece which is arranged on other end of the second swing arm and presses on upper surface of arc-shaped shell.

9. The positioning tool for CNC machining of an arc-shaped shell according to claim 1, characterized in that: The first limiting module includes first limiting assembly and second limiting assembly which press on front side of arc-shaped shell, the first limiting assembly includes supporting cross bar which extends in front and rear directions and roller which is rotatably arranged on the supporting cross bar and presses on front side of arc-shaped shell. The second limiting assembly comprises a mounting frame arranged on the base and a limiting block arranged on the mounting frame, the limiting block is elastically and floatingly arranged on the mounting frame by a second spring, and a third arc-shaped positioning groove is arranged on the limiting block.

10. The positioning tool for CNC machining of an arc-shaped shell according to claim 1, characterized in that: The second limiting assembly comprises a limiting seat and a limiting rod movably arranged in the limiting seat, the limiting rod is elastically and floatingly arranged in the limiting seat by a third spring, and an avoiding opening avoiding the limiting seat is arranged on the moving positioning plate.

Images