Rapid positioning and clamping device of high-strength vehicle body covering part stamping die
The high-strength car body cover component pressing die with a quick positioning and clamping device addresses the inefficiencies of existing molds by providing adaptable and rapid mold positioning, reducing costs and enhancing production efficiency.
Patent Information
- Application Number
- CN202421883710.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-06
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2034-08-06
AI Technical Summary
In the prior art, the positioning and clamping structure of the stamping mold of the vehicle body cover part is not universal, which leads to difficulty in replacing the mold, affects production efficiency and increases costs.
A quick positioning and clamping device including a stamping platform, a lower module, an upper module and a frame is designed. By setting limiting grooves and limiting blocks on the stamping platform, combined with limiting pins, guide grooves and return springs, the rapid positioning and clamping of the mold is achieved.
It realizes rapid positioning and clamping of molds, and is suitable for stamping processing of various vehicle body coverings, improving production efficiency and reducing production costs.
Smart Images
Figure CN223097815U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of stamping processing of vehicle body covering parts, in particular to a rapid positioning and clamping device for a high-strength vehicle body covering part stamping die. Background Technique
[0002] Vehicle body covering parts refer to the surface or internal parts in the shape of a space made of metal sheets that cover the engine and chassis and form the cab and the vehicle body. They can be divided into three categories according to functions and positions: external covering parts, internal covering parts, and skeleton covering parts. A stamping die is a special process equipment that processes materials into parts in cold stamping processing and is called a cold stamping die. Stamping is a pressure processing method in which, at room temperature, a die installed on a press applies pressure to the material to cause separation or plastic deformation, thereby obtaining the required parts.
[0003] During the stamping process of different types of vehicle body covering parts, corresponding dies need to be selected. The die generally consists of an upper part and a lower part, and both the upper and lower dies need to be connected to the stamping equipment. When connecting, the upper and lower dies need to be positioned, and it is necessary to ensure a firm connection between the die and the stamping equipment. In the prior art, when replacing different types of dies, it is often necessary to cooperate with a specific positioning and clamping structure to firmly fix the die on the stamping equipment. The positioning and clamping structure is not universal, which will lead to an increase in production costs. At the same time, the existing positioning and clamping structure is difficult to quickly position different dies, affecting production efficiency. Content of the Utility Model
[0004] The purpose of the utility model is to provide a rapid positioning and clamping device for a high-strength vehicle body covering part stamping die to solve the problems raised in the above background technique.
[0005] To achieve the above purpose, the utility model provides the following technical solution:
[0006] A rapid positioning and clamping device for a high-strength vehicle body covering part stamping die, comprising
[0007] A stamping platform, on which a lower die set and a first positioning mechanism for quickly positioning the lower die set are arranged, and a lower die and a second positioning mechanism for clamping and positioning the lower die are arranged in the lower die set;
[0008] A stamping cylinder, on the stamping end of which an upper die set is arranged. An upper die is arranged in the upper die set. The upper die is arranged opposite to and cooperates with the lower die for stamping and forming high-strength vehicle body covering parts. A third positioning mechanism for clamping and positioning the upper die is also arranged in the upper die set;
[0009] A frame for mounting the stamping platform, the stamping cylinder, the lower die set disposed on the stamping platform, and the upper die set disposed at the stamping end of the stamping cylinder.
[0010] As a further solution of the present utility model: on both sides near the center of the upper surface of the stamping platform, guiding grooves are provided. At both ends corresponding to the front sides of the two guiding grooves on the upper surface of the stamping platform, first limiting grooves are provided. On the rear side corresponding to the two guiding grooves on the upper surface of the stamping platform, second limiting grooves are provided. Limiting blocks are slidably connected to both sides inside the second limiting grooves and in the two first limiting grooves. The lower die set is disposed on the upper surface of the stamping platform, and a plurality of the limiting blocks are respectively located at the front and rear ends of the lower die set. The plurality of limiting blocks cooperate to abut and fix the lower die set on the stamping platform.
[0011] As a further solution of the present utility model: Limiting holes penetrating up and down are provided between each of the plurality of limiting blocks and the inner walls of the corresponding first limiting grooves and second limiting grooves. A limiting pin is provided on each of the limiting blocks, and one end of the limiting pin is inserted into the corresponding limiting hole. The plurality of limiting blocks are respectively connected and fixed to the corresponding first limiting grooves and second limiting grooves through the cooperation of the limiting pins and the limiting holes. The first limiting grooves, the second limiting grooves, the guiding grooves and the corresponding limiting blocks cooperate to form the first positioning mechanism for quickly positioning the lower die set.
[0012] As a further solution of the present utility model: The lower die set includes a lower die base. On one side corresponding to the two guiding grooves at the bottom of the lower die base, guiding strips are fixed respectively. The two guiding strips are respectively slidably connected in the guiding grooves on the corresponding side. A lower die chuck is disposed on the top of the lower die base. A lower die is clamped on the lower die chuck. Lower die angle plates are provided at the four corners of the lower die chuck, and the lower die chuck is detachably connected to the lower die base through the lower die angle plates at its four corners.
[0013] As a further solution of the present utility model: The lower die chuck is a hollow frame structure, and a positioning ring is provided at the center inside it. The positioning ring is a ring structure penetrating up and down, and a cross beam is integrally formed on the outer periphery of the positioning ring. The end of the cross beam away from the positioning ring is connected and fixed to the lower die chuck. A sliding groove is provided on the upper surface of each end of the cross beam. A sliding rod is fixed in each of the plurality of sliding grooves, and a clamping block is slidably sleeved on each sliding rod. The plurality of clamping blocks respectively abut against the outer wall of the lower die on the corresponding side. The plurality of clamping blocks cooperate to clamp and fix the lower die on the lower die chuck.
[0014] As a further solution of the present utility model: multiple clamping blocks are respectively slidably connected in the corresponding chutes on one side, return springs are sleeved on multiple sliding rods, and two ends of multiple return springs are respectively connected and fixed to the corresponding clamping blocks on one side and the inner wall on one side of the chute. Multiple clamping blocks and multiple return springs cooperate to form the second positioning mechanism for positioning and clamping the lower die.
[0015] As a further solution of the present utility model: the upper die module includes an upper die base, an upper die chuck is arranged at the bottom of the upper die base, upper die angle plates are arranged at four corners of the upper die chuck, and the upper die chuck is detachably connected to the bottom of the upper die base through the upper die angle plates at its four corners. A clamping groove is formed at the center of the bottom of the upper die chuck, an upper die is clamped in the clamping groove, and the lower surface of the upper die extends below the upper die chuck.
[0016] As a further solution of the present utility model: through holes are respectively formed in the inner wall of the upper die chuck around the clamping groove, positioning rods are slidably inserted in multiple through holes, positioning holes are formed in one side of the upper die inner wall corresponding to multiple through holes, multiple positioning holes are concentric and coaxial with the corresponding through holes on one side and have the same aperture, and one ends of multiple positioning rods are respectively inserted into the corresponding positioning holes on one side. The upper die is limited and fixed in the clamping groove through the cooperation of the positioning rods and the positioning holes.
[0017] As a further solution of the present utility model: one ends of multiple positioning rods all extend into the clamping groove, return springs are sleeved on multiple positioning rods, and two ends of multiple return springs are respectively connected and fixed to the corresponding positioning rods and the inner wall on one side of the upper die chuck. Multiple positioning rods, multiple return springs, multiple through holes and multiple positioning holes cooperate to form the third positioning mechanism for positioning and clamping the upper die.
[0018] Compared with the prior art, the beneficial effects of the present utility model are as follows:
[0019] 1. In the present utility model, a first limiting groove, a second limiting groove and a guiding groove are formed on the upper surface of the stamping platform, limiting blocks are arranged in the limiting grooves, and the lower die module can be quickly positioned and fixed on the stamping platform through the cooperation of the first limiting groove, the second limiting groove, the guiding groove and the corresponding limiting blocks. Further, a lower die chuck is detachably connected to the top of the lower die base, and the lower die can be clamped and fixed in the chuck through the cooperation of multiple clamping blocks and corresponding return springs in the lower die chuck, etc., to complete the quick fixation of the lower die.
[0020] 2. In the present utility model, the upper die and the lower die are arranged opposite to each other, and the stamping forming of high-strength vehicle body covering parts is carried out through the cooperation of the upper and lower dies. There is no obstruction on the contact surface of the upper and lower dies, which will not affect the forming quality of the stamping parts. At the same time, both the upper and lower dies are detachably connected to the frame. When stamping a covering part with a specific shape is required, the die can be easily replaced. The clamping and positioning structure of the die is applicable to most stamping scenarios, the device has stronger adaptability and wider application range, which can meet the daily processing needs and save production costs at the same time. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for describing the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present utility model, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.
[0022] Figure 1 It is a schematic structural diagram of the present utility model.
[0023] Figure 2 It is a front view schematic diagram of the present utility model.
[0024] Figure 3 It is an exploded structural diagram of the stamping platform and the lower die module in the present utility model.
[0025] Figure 4 It is an exploded structural diagram of the lower die module in the present utility model.
[0026] Figure 5 It is a first perspective view of the exploded structure of the upper die module in the present utility model.
[0027] Figure 6 It is a second perspective view of the exploded structure of the upper die module in the present utility model.
[0028] Annotation of reference numerals in the drawings: 1 - frame, 2 - stamping platform, 21 - first limiting groove, 22 - second limiting groove, 23 - limiting block, 24 - limiting pin, 25 - limiting hole, 26 - guiding groove, 3 - stamping cylinder, 4 - upper die module, 41 - upper die base, 42 - upper die chuck, 43 - positioning rod, 44 - upper die, 45 - positioning hole, 46 - upper die gusset, 47 - clamping groove, 48 - through hole, 5 - lower die module, 51 - guiding strip, 52 - lower die base, 53 - lower die chuck, 54 - cross beam, 55 - sliding groove, 56 - sliding rod, 57 - lower die, 58 - positioning ring, 59 - clamping block, 510 - return spring, 511 - lower die gusset. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0029] The following embodiments will describe the present utility model in detail with reference to the accompanying drawings. In the drawings or descriptions, similar or identical parts are denoted by the same reference numerals, and in actual applications, the shapes, thicknesses or heights of the various components can be enlarged or reduced. The various embodiments listed for the present utility model are only used to illustrate the present utility model and are not intended to limit the scope of the present utility model. Any obvious modification or change made to the present utility model does not depart from the spirit and scope of the present utility model.
[0030] Embodiment 1
[0031] Please refer to Figures 1 - 2 , in the embodiment of the present utility model, a rapid positioning and clamping device for a stamping die of a high-strength vehicle body covering member includes a frame 1, a stamping platform 2 and a stamping cylinder 3. The frame 1 is used to install the stamping platform 2 and the stamping cylinder 3. A lower die set 5 is arranged on the stamping platform 2, and an upper die set 4 is arranged at the stamping end of the stamping cylinder 3. The upper die set 4 and the lower die set 5 are arranged opposite to each other and cooperate with each other for stamping and forming a high-strength vehicle body covering member.
[0032] Please refer to Figure 3 , on both sides of the upper surface of the stamping platform 2 near the center, guiding grooves 26 are opened. At both ends corresponding to the front sides of the two guiding grooves 26 on the upper surface of the stamping platform 2, first limiting grooves 21 are opened. On the rear side corresponding to the two guiding grooves 26 on the upper surface of the stamping platform 2, second limiting grooves 22 are opened. Limiting blocks 23 are slidably connected to both sides inside the second limiting grooves 22 and in the two first limiting grooves 21. Limiting holes 25 penetrating up and down are opened between the multiple limiting blocks 23 and the inner walls of the corresponding first limiting grooves 21 and second limiting grooves 22. A limiting pin 24 is arranged on each limiting block 23, and one end of the limiting pin 24 is inserted into the corresponding limiting hole 25. The multiple limiting blocks 23 are respectively connected and fixed to the corresponding first limiting grooves 21 and second limiting grooves 22 through the cooperation of the limiting pins 24 and the limiting holes 25.
[0033] In this embodiment, the first limiting grooves 21, the second limiting grooves 22 and the guiding grooves 26 are opened on the upper surface of the stamping platform 2, and the limiting blocks 23 are arranged in the limiting grooves. Through the cooperation of the first limiting grooves 21, the second limiting grooves 22, the guiding grooves 26 and the corresponding limiting blocks 23, the lower die set 5 can be quickly positioned and fixed on the stamping platform 2. The first limiting grooves 21, the second limiting grooves 22, the guiding grooves 26 and the corresponding limiting blocks 23 cooperate with each other to jointly constitute the first positioning mechanism in this device for quickly positioning the lower die set 5.
[0034] Please refer to Figure 4, the lower die module 5 includes a lower die base 52. On one side of the lower die base 52 corresponding to the two guide grooves 26 at the bottom, a guide bar 51 is fixed. The two guide bars 51 are respectively slidably connected in the guide grooves 26 on the corresponding side. On the top of the lower die base 52, a lower die chuck 53 is provided. The lower die chuck 53 is a hollow frame structure, and a positioning ring 58 is provided at the center of its interior. The positioning ring 58 is a ring structure that penetrates up and down, and a cross beam 54 is integrally formed on the outer periphery of the positioning ring 58. One end of the cross beam 54 away from the positioning ring 58 is connected and fixed to the lower die chuck 53. A chute 55 is formed on the upper surface of each end of the cross beam 54;
[0035] A slide bar 56 is fixed in each of the multiple chutes 55, and a clamping block 59 is slidably sleeved on each slide bar 56. The multiple clamping blocks 59 are respectively slidably connected in the corresponding chutes 55 on one side. A return spring 510 is sleeved on each of the multiple slide bars 56. The two ends of the multiple return springs 510 are respectively connected and fixed to the clamping block 59 on the corresponding side and the inner wall of one side of the chute 55. A lower die 57 is placed on the lower die chuck 53. The multiple clamping blocks 59 respectively abut against the outer wall of the lower die 57 on the corresponding side. The multiple clamping blocks 59 cooperate to clamp and fix the lower die 57 on the lower die chuck 53. Lower die angle plates 511 are provided at the four corners of the lower die chuck 53, and the lower die chuck 53 is detachably connected to the lower die base 52 through the lower die angle plates 511 at its four corners;
[0036] In this embodiment, the lower die base 52 is slidably connected to the top of the stamping platform 2 through the guide bars 51 on both sides of its bottom. The guide bars 51 cooperate with the guide grooves 26 to position the lower die base 52 on the stamping platform 2. At this time, the lower die base 52 is movable relative to the stamping platform 2. It is necessary to use multiple limit blocks 23 on the front and back sides of the upper surface of the stamping platform 2 to respectively abut against the front and back ends of the lower die base 52, so as to fix the lower die base 52 on the stamping platform 2. The lower die chuck 53 is detachably connected to the top of the lower die base 52. By the cooperation of the multiple clamping blocks 59 and the corresponding return springs 510 in the lower die chuck 53, the lower die 57 can be clamped and fixed in the chuck, completing the fixation of the lower die 57. In this device, through the cooperation of the lower die chuck 53 and the clamping blocks 59, return springs 510 and other components inside the chuck, a positioning and clamping structure for the lower die 57 can be formed.
[0037] Embodiment 2
[0038] Please refer to Figures 5 - 6, on the basis of Embodiment 1, the upper die set 4 includes an upper die base 41. At the bottom of the upper die base 41, there is an upper die chuck 42. At the four corners of the upper die chuck 42, there are upper die angle plates 46. The upper die chuck 42 is detachably connected to the bottom of the upper die base 41 through the upper die angle plates 46 at its four corners. At the center of the bottom of the upper die chuck 42, there is a card slot 47. A upper die 44 is clamped in the card slot 47. The lower surface of the upper die 44 extends below the upper die chuck 42. Through holes 48 are opened around the inner wall of the upper die chuck 42 corresponding to the card slot 47. Positioning rods 43 are slidably inserted into the plurality of through holes 48;
[0039] One end of each of the plurality of positioning rods 43 extends into the card slot 47. Springs are sleeved on the plurality of positioning rods 43, and both ends of the plurality of springs are fixedly connected to the corresponding positioning rod 43 and the inner wall of one side of the upper die chuck 42 respectively. Positioning holes 45 are opened on one side of the inner wall of the upper die 44 corresponding to the plurality of through holes 48. The plurality of positioning holes 45 are concentric and coaxial with the corresponding through holes 48 on one side and have the same aperture. One end of each of the plurality of positioning rods 43 is inserted into the positioning hole 45 on the corresponding side. The upper die 44 is limited and fixed in the card slot 47 through the cooperation of the positioning rods 43 and the positioning holes 45;
[0040] In this embodiment, a card slot 47 is provided in the upper die chuck 42. The card slot 47 is used to accommodate the upper die 44. Positioning holes 45 are opened on the inner wall of the upper die 44. Correspondingly, through holes 48 are opened at the corresponding positions on the inner wall of the upper die chuck 42. The through holes 48 and the positioning holes 45 are located on the same straight line. Positioning rods 43 are inserted into the through holes 48. One end of the positioning rod 43 is inserted into the positioning hole 45. By inserting the plurality of positioning rods 43 into the positioning holes 45 on the inner wall of the upper die 44 from different directions respectively, the upper die 44 can be limited and fixed in the card slot 47 to prevent the upper die 44 from falling off during the stamping process. In this device, through the cooperation of the upper die chuck 42 and the card slot 47, positioning rods 43, etc. provided in the chuck, a positioning and clamping structure for the upper die 44 can be formed.
[0041] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be encompassed by the present invention. Any reference signs in the claims should not be regarded as limiting the claims involved.
[0042] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only includes an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A rapid positioning and clamping device for a stamping die of a high-strength vehicle body covering part, characterized in that, including a stamping platform (2), on which a lower die set (5) and a first positioning mechanism for quickly positioning the lower die set (5) are arranged, and a lower die (57) and a second positioning mechanism for clamping and positioning the lower die (57) are arranged in the lower die set (5); a stamping cylinder (3), an upper die set (4) is arranged at the stamping end of the stamping cylinder (3), an upper die (44) is arranged in the upper die set (4), the upper die (44) is arranged opposite to and cooperates with the lower die (57) for stamping and forming high-strength vehicle body cover parts, and a third positioning mechanism for clamping and positioning the upper die (44) is further arranged in the upper die set (4); a frame (1) for mounting the stamping platform (2) and the stamping cylinder (3), the lower die set (5) arranged on the stamping platform (2), and the upper die set (4) arranged at the stamping end of the stamping cylinder (3).
2. The quick positioning and clamping device for the stamping die of the high-strength vehicle body covering part according to claim 1, characterized in that, Guide grooves (26) are respectively formed on both sides of the upper surface of the stamping platform (2) near the center, first limiting grooves (21) are respectively formed at both ends of the front side of the upper surface of the stamping platform (2) corresponding to the two guide grooves (26), second limiting grooves (22) are formed at the rear side of the upper surface of the stamping platform (2) corresponding to the two guide grooves (26), limiting blocks (23) are slidably connected to both sides in the second limiting grooves (22) and in the two first limiting grooves (21), the lower die set (5) is arranged on the upper surface of the stamping platform (2), and a plurality of the limiting blocks (23) are respectively located at the front and rear ends of the lower die set (5), and the plurality of the limiting blocks (23) cooperate to abut and fix the lower die set (5) on the stamping platform (2).
3. The rapid positioning and clamping device for the stamping die of the high-strength vehicle body covering part according to claim 2, characterized in that, Limiting holes (25) penetrating up and down are formed between the plurality of limiting blocks (23) and the inner walls of the corresponding first limiting grooves (21) and second limiting grooves (22), a limiting pin (24) is arranged on each limiting block (23), and one end of the limiting pin (24) is inserted into the corresponding limiting hole (25). The plurality of limiting blocks (23) are respectively connected and fixed to the corresponding first limiting grooves (21) and second limiting grooves (22) through the cooperation of the limiting pins (24) and the limiting holes (25). The first limiting grooves (21), the second limiting grooves (22), the guide grooves (26) and the corresponding limiting blocks (23) cooperate to form the first positioning mechanism for quickly positioning the lower die set (5).
4. The rapid positioning and clamping device for the stamping die of the high-strength vehicle body covering part according to claim 3, characterized in that, The lower die module (5) includes a lower die base (52). On one side of the bottom of the lower die base (52) corresponding to the two guiding grooves (26), a guiding bar (51) is fixed respectively. The two guiding bars (51) are respectively slidably connected in the guiding grooves (26) on the corresponding side. On the top of the lower die base (52), a lower die chuck (53) is provided. A lower die (57) is clamped on the lower die chuck (53). Lower die angle plates (511) are provided at the four corners of the lower die chuck (53), and the lower die chuck (53) is detachably connected to the lower die base (52) through the lower die angle plates (511) at its four corners.
5. The rapid positioning and clamping device for the stamping die of the high-strength vehicle body covering part according to claim 4, characterized in that, The lower die chuck (53) is a hollow frame structure, and a positioning ring (58) is provided at the center of its interior. The positioning ring (58) is a ring structure penetrating up and down. A cross beam (54) is integrally formed on the outer periphery of the positioning ring (58). One end of the cross beam (54) far from the positioning ring (58) is fixedly connected to the lower die chuck (53). A chute (55) is opened on the upper surface of each end of the cross beam (54). A slide bar (56) is fixed in each of the plurality of chutes (55), and a clamping block (59) is slidably sleeved on each slide bar (56). The plurality of clamping blocks (59) respectively abut against the outer wall of the lower die (57) on the corresponding side. The plurality of clamping blocks (59) cooperate to clamp and fix the lower die (57) on the lower die chuck (53).
6. The rapid positioning and clamping device for the stamping die of the high-strength vehicle body covering part according to claim 5, characterized in that The plurality of clamping blocks (59) are respectively slidably connected in the chutes (55) on the corresponding side. A return spring (510) is sleeved on each of the plurality of slide bars (56). Two ends of the plurality of return springs (510) are respectively fixedly connected to the clamping block (59) on the corresponding side and the inner wall of one side of the chute (55). The plurality of clamping blocks (59) and the plurality of return springs (510) cooperate to form the second positioning mechanism for positioning and clamping the lower die (57).
7. The rapid positioning and clamping device for the stamping die of the high-strength vehicle body covering part according to claim 1 or 6, characterized in that, The upper die module (4) includes an upper die base (41). A upper die chuck (42) is provided at the bottom of the upper die base (41). Upper die angle plates (46) are provided at the four corners of the upper die chuck (42). The upper die chuck (42) is detachably connected to the bottom of the upper die base (41) through the upper die angle plates (46) at its four corners. A clamping groove (47) is opened at the center of the bottom of the upper die chuck (42). An upper die (44) is clamped in the clamping groove (47). The lower surface of the upper die (44) extends below the upper die chuck (42).
8. The rapid positioning and clamping device for the stamping die of the high-strength vehicle body covering part according to claim 7, characterized in that, The inner wall of the upper die chuck (42) corresponding to the periphery of the card slot (47) is provided with through holes (48). A positioning rod (43) is slidably inserted into each of the through holes (48). The inner wall of the upper die (44) corresponding to one side of each of the through holes (48) is provided with a positioning hole (45). The positioning holes (45) are concentric and coaxial with the corresponding through holes (48) on one side and have the same aperture. One ends of the positioning rods (43) are respectively inserted into the positioning holes (45) on the corresponding side. The upper die (44) is limited and fixed in the card slot (47) through the cooperation of the positioning rods (43) and the positioning holes (45).
9. The rapid positioning and clamping device for the stamping die of the high-strength vehicle body covering part according to claim 8, characterized in that, One ends of the positioning rods (43) all extend into the card slot (47). Springs are sleeved on the positioning rods (43). Two ends of each of the springs are respectively connected and fixed to the corresponding positioning rod (43) and the inner wall on one side of the upper die chuck (42). The positioning rods (43), the springs, the through holes (48) and the positioning holes (45) cooperate with each other to form the third positioning mechanism for positioning and clamping the upper die (44).