An adaptive last holding jig

Abstract

The application relates to the technical field of shoemaking equipment, in particular to a self-adaptive last clamping jig, which comprises a toe supporting mechanism, a pin moving mechanism and a clamping mechanism arranged in sequence from front to back, the clamping mechanism comprises a clamping cylinder and two clamping jigs symmetrically arranged at the front end of the clamping cylinder, the two clamping jigs are arranged in an eight-shaped mode, and two second-stage flexible clamping jaws are additionally arranged on the two clamping jigs, the two second-stage flexible clamping jaws are symmetrically arranged left and right, wherein the first stage is a fractal vice structure, and the second stage is an outer self-adaptive structure; the second-stage flexible clamping jaws complete rough clamping through the first stage, provide basic fixing force, the second stage is matched with the surface curve of a last, automatic positioning and self-adaptive firm clamping are realized, manual intervention is reduced, and the application has the characteristics of improving production efficiency.

Description

Technical Field

[0001] This application relates to the field of shoemaking equipment technology, and in particular to an adaptive last clamping fixture. Background Technology

[0002] The last serves as a molding mold for shoes, shaping the shoe's outline and curvature by simulating the shape of the foot. The last clamp mainly uses multi-point clamping to fix the last and prevent surface scratches.

[0003] In related technologies, the last clamps in the current shoe manufacturing industry mainly adopt rigid clamping structures, which directly clamp the last through metal claws. The advantage is that the structure is simple, but it cannot adapt to changes in curved surfaces and requires manual adjustment to adapt to different shoe sizes or last shapes, which is inefficient. The existing last clamps have the following problems: they cannot actively take into account the synchronous fitting of multi-directional irregular curved surfaces, manual adjustment is time-consuming, and seriously affect production efficiency. Utility Model Content

[0004] To improve production efficiency, this application provides an adaptive last clamping fixture.

[0005] The adaptive last clamping fixture provided in this application adopts the following technical solution: An adaptive last clamping fixture includes a shoe toe support mechanism, a pin moving mechanism, and a clamping mechanism arranged sequentially from front to back. The clamping mechanism includes a clamping cylinder and two clamping fixtures symmetrically arranged at the front end of the clamping cylinder. The two clamping fixtures are arranged in a figure-eight shape and each is equipped with a second-order flexible gripper. The two second-order flexible grippers are symmetrically arranged from left to right. The first order is a fractal vise structure, and the second order is an outer adaptive structure.

[0006] By adopting the above technical solution, the two-stage flexible gripper completes coarse clamping in the first stage, providing basic fixing force; the second stage conforms to the surface curve of the last, realizing automatic positioning and adaptive firm clamping, reducing manual intervention and improving production efficiency.

[0007] Preferably, the fractal vise structure is composed of a first-stage rotating plate and a first-stage rotating medium, wherein the first-stage rotating plate is rotatably connected to the rotating top of the clamping fixture through the first-stage rotating medium; the outer adaptive structure is composed of no less than two second-stage rotating plates and second-stage rotating mediums, wherein the second-stage rotating plates are rotatably connected to the inner side of the first-stage rotating plate through the second-stage rotating medium.

[0008] By adopting the above technical solution, the first-stage rotating plate and the second-stage rotating plate respectively completed the angle adjustment of the basic clamping surface and the multi-level flexible adjustment, reducing the occurrence of preferential contact on the inner side of the figure-eight fixture and irregularities at the clamping point of the last.

[0009] Preferably, the first-stage rotating medium is a large-sized round-headed crimping screw, and the second-stage rotating medium has a T-slot structure or is a small-sized round-headed crimping screw.

[0010] By adopting the above technical solutions, both connection structures can form a stable rotary pair and use mechanical cooperation to limit the direction of rotation, while reducing the fatigue risk at the rotary connection and improving the reliability and durability of the fixture.

[0011] Preferably, both the first-stage rotating plate and the second-stage rotating plate have a semi-circular arc structure, and the inner side of the first-stage rotating plate has a rotating groove with a matching shape corresponding to the second-stage rotating plate.

[0012] By adopting the above technical solution, the semi-circular arc design enables the rotating plate to form a natural arc motion trajectory when rotating around the axis, which fits better with the curved surface of the last, reduces the risk of interference during the clamping process, and reduces offset or jamming by ensuring the synchronous movement of the two-stage rotating plates.

[0013] Preferably, a third rotating plate is fixed to the inner side of the second rotating plate, and the third rotating plate has a semi-circular arc structure or a block structure.

[0014] By adopting the above technical solution, a progressive contact is formed, which further improves the contact fit and reduces the clamping dead zone.

[0015] Preferably, the top of the pin moving mechanism is provided with a pin fixing pad, the pin fixing pad includes a pad body and a cylindrical pin, the head of the cylindrical pin extends downward and is provided with a positioning part coaxial with the pin body, the positioning part is provided with annular grooves spaced along the length direction, the cylindrical pin is fixed to the top of the pad body through the positioning part and the shaft hole of the pad body, and the tail of the cylindrical pin has a hemispherical structure for connecting with the pin hole at the top of the last.

[0016] By adopting the above technical solution, the positioning part of the cylindrical pin forms an interference fit with the shaft hole of the pad body through the annular groove, which ensures the verticality and axial stability of the pin. At the same time, the hemispherical structure at the tail of the pin allows for quick alignment and insertion into the pin hole at the top of the last, reducing installation errors.

[0017] Preferably, a handle bolt is connected to each of the left and right sides of the positioning part, and the two handle bolts are coaxially arranged. The head of the handle bolt extends out of the side wall of the pad body, and its rod is built into the pad body and the height of the cylindrical pin can be adjusted by rotation.

[0018] By adopting the above technical solution, operators can manually rotate the handle bolt to change the tightness, thereby releasing and locking the height of the cylindrical pin and achieving flexible adjustment.

[0019] Preferably, the toe support mechanism can move forward and backward and rise and fall, and the pin moving mechanism is used to move the pin forward and backward and left and right to adapt to the offset of the left and right pin hole positions.

[0020] By adopting the above technical solutions, the positioning, calibration, adjustment, and locking support of the last are comprehensively realized, thereby improving clamping accuracy and compatibility.

[0021] In summary, this application includes at least one of the following beneficial technical effects: 1. By adjusting the angle of the basic clamping surface and through multi-level flexible adjustment, the occurrence of preferential contact on the inner side of the figure-eight fixture and irregularities at the clamping point of the last is reduced, achieving automatic positioning and adaptive firm clamping, reducing manual intervention and improving production efficiency; 2. The semi-circular arc design of the rotating plate can form a natural arc motion trajectory when rotating around the axis, which fits better with the curved surface of the last, reduces the risk of interference during the clamping process, and reduces offset or jamming by ensuring the synchronous movement of the two-stage rotating plates. 3. It comprehensively realizes the positioning, calibration, adjustment and locking support of the last, improving clamping accuracy and compatibility. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of this application.

[0023] Figure 2 This is a schematic diagram showing the cooperation relationship between the first-stage rotating plate and the second-stage rotating plate in Embodiment 1 of this application.

[0024] Figure 3 This is an exploded view of the pin fixing pad in Embodiment 1 of this application.

[0025] Figure 4 This is a schematic diagram of the overall structure of Embodiment 2 of this application.

[0026] Figure 5 This is a schematic diagram of the usage scenario of Embodiment 2 of this application.

[0027] Figure 6 This is a schematic diagram of the cooperation relationship between the clamping fixture and the second-order flexible gripper in Embodiment 2 of this application.

[0028] Explanation of reference numerals in the attached drawings: 1. Toe support mechanism; 2. Pin moving mechanism; 3. Pin fixing pad; 31. Pad body; 32. Cylindrical pin; 33. Positioning part; 331. Annular groove; 332. Handle bolt; 4. Clamping mechanism; 41. Clamping cylinder; 42. Clamping fixture; 43. Second-stage flexible gripper; 431. First-stage rotating medium; 432. First-stage rotating plate; 433. Second-stage rotating medium; 434. Second-stage rotating plate; 435. Third-stage rotating plate. Detailed Implementation

[0029] The following is in conjunction with the appendix Figure 1-6 This application will be described in further detail.

[0030] Example 1 This application discloses an adaptive last clamping fixture. (Refer to...) Figure 1-3 An adaptive last clamping fixture includes a shoe toe support mechanism 1, a pin moving mechanism 2, and a clamping mechanism 4 arranged sequentially from front to back. The shoe toe support mechanism 1 can move back and forth and rise and fall. The pin moving mechanism 2 is used to move the pins back and forth and left and right to adapt to the offset of the left and right code pin hole positions.

[0031] Correspondingly, the toe support mechanism 1, as the front-end fixing unit, has a uniform contact curved surface to stably support the head of the last, thereby reducing displacement or deformation during processing. It also matches the length and longitudinal curve changes of different lasts through front and rear position adjustment and height adjustment functions, providing a standard positioning reference for subsequent clamping. The pin moving mechanism 2, as the intermediate adjustment unit, precisely aligns with the pin hole at the top of the last through the axial movement of the pin, thereby achieving fine adjustment or positioning compensation of the last position and ensuring that the last is in the preset position before clamping.

[0032] Specifically, the clamping mechanism 4 includes a clamping cylinder 41 and two clamping fixtures 42 symmetrically arranged at the front end of the clamping cylinder 41. The two clamping fixtures 42 are arranged in a figure-eight shape and are each equipped with a second-order flexible gripper 43. The two second-order flexible grippers 43 are symmetrically arranged on the left and right sides to form a mechanical self-locking effect, which can evenly distribute the clamping force and reduce the damage to the last caused by local stress concentration.

[0033] Furthermore, the first stage is a fractal vise structure, and the second stage is an outer adaptive structure. In this embodiment, the fractal vise structure is composed of a first-stage rotating plate 432 and a first-stage rotating medium 431. The first-stage rotating plate 432 is rotatably connected to the top of the clamping fixture 42 through the first-stage rotating medium 431. The outer adaptive structure is composed of two second-stage rotating plates 434 and a second-stage rotating medium 433. The two second-stage rotating plates 434 are rotatably connected to the inner side of the first-stage rotating plate 432 through the second-stage rotating medium 433.

[0034] Therefore, the first stage realizes the angle adjustment of the basic clamping surface. This structure provides the initial clamping force and adapts to the contours of different sizes of lasts through the opening and closing action of the rotating plate, forming a mechanical coarse positioning and reducing the problem of preferential contact on the inner side of the figure-eight fixture. The second stage constitutes a multi-level flexible adjustment unit. Through the independent movement of the two rotating plates, it can automatically fit the irregular curves of the last surface, forming a composite clamping mode of "rigid positioning + flexible fitting".

[0035] In summary, this device achieves rapid coarse positioning and high-precision flexible clamping of the last head through graded rotation and multi-plate adaptive design. It is suitable for batch processing scenarios of complex curved surfaces or easily deformable materials. Compared with traditional clamping fixtures, it reduces manual intervention and effectively improves production efficiency.

[0036] Specifically, in this embodiment, the first-stage rotating medium 431 is set as a large-size round-headed rivet screw, and the second-stage rotating medium 433 is a T-slot structure. This structure design forms a stable rotating pair through the cooperation of the T-slot and the corresponding key, which allows the second-stage rotating plate 434 to rotate radially relative to the first-stage rotating plate 432 and restricts its axial displacement. At the same time, it effectively disperses stress concentration, improves fatigue resistance, and realizes multi-degree-of-freedom rotation adjustment of the two-stage rotating plates in a single plane.

[0037] On the other hand, both the first-stage rotating plate 432 and the second-stage rotating plate 434 have a semi-circular arc structure, and the inner side of the first-stage rotating plate 432 is provided with a rotating groove of a matching shape corresponding to the second-stage rotating plate 434.

[0038] Therefore, the semi-circular arc design allows the rotating plate to form a natural arc motion trajectory when rotating around the axis, which fits the curved surface of the last better, reduces the risk of interference during clamping, and reduces offset or jamming. This not only enhances clamping stability but also maintains the overall compactness of the fixture.

[0039] Furthermore, the rotating groove on the inner side of the first-stage rotating plate 432 serves as a dynamic guide for the second-stage rotating medium 433. The groove plate fitting design allows the rotational force to be directly transmitted to the contact surface, reducing energy loss and ensuring the synchronization of the movement of the two-stage rotating plates. This improves the clamping response speed and is suitable for processing scenarios that require rapid adjustment.

[0040] Meanwhile, in this embodiment, a third rotating plate 435 with a block structure is fixed inside the second rotating plate. It is screwed to the inside of the second rotating plate 434 by four countersunk screws to form a progressive contact, further conforming to the micro-curved surface of the last. The rectangular cross-section of the block structure maximizes the effective contact area within a limited volume, reducing the clamping dead zone.

[0041] Corresponding to the above process, in this embodiment, the clamping cylinder 41 adopts an SMC finger cylinder, which drives two clamping fixtures 42 respectively through a dual-piston symmetrical structure. It has high repeatability and positioning accuracy and a wide range of clamping force adjustment. The structure is simple and reliable. The main body is made of aluminum alloy, and the piston and fingers are made of stainless steel, ensuring long-term stability and requiring less maintenance. It is suitable for precision clamping scenarios.

[0042] In addition, a pin fixing pad 3 is installed on the top of the pin moving mechanism 2. The pin fixing pad 3 includes a pad body 31 and a cylindrical pin 32. The head of the cylindrical pin 32 extends downward and is provided with a positioning part 33 coaxial with the pin body. The positioning part 33 is provided with annular grooves 331 spaced along the length direction. The cylindrical pin 32 is fixed to the top of the pad body 31 through the positioning part 33 and the shaft hole of the pad body 31.

[0043] Therefore, the positioning part 33 of the cylindrical pin 32 forms an interference fit with the shaft hole of the pad body 31 through the annular groove 331, which ensures the perpendicularity and axial stability of the pin. The design of the annular groove 331 can enhance the frictional resistance and reduce the risk of vibration and loosening.

[0044] Furthermore, the tail of the cylindrical pin 32 has a hemispherical structure, which can be quickly aligned and inserted into the pin hole at the top of the last. The hemispherical design compensates for slight alignment deviations, reduces jamming or installation errors, and comprehensively improves anti-loosening performance, positioning accuracy and assembly convenience. It is suitable for mechanical connections that require repeated disassembly and assembly or are in high-vibration environments.

[0045] Meanwhile, a handle bolt 332 is connected to each of the left and right sides of the positioning part 33, and the two handle bolts 332 are coaxially arranged. The head of the handle bolt 332 extends out of the side wall of the pad body 31, and its rod is built into the pad body 31 and the height of the cylindrical pin 32 can be adjusted by rotation.

[0046] Correspondingly, the coaxial handle bolts 332 on both sides are linked by threads, and their exposed design facilitates manual adjustment. The operator can rotate any bolt to change the tightness of the threaded fit, thereby releasing the lock on the pin positioning part 33. Then, the operator can lift or press the cylindrical pin 32 to reach the preset position and then retighten the handle bolt 332 to achieve fine adjustment of the pin height. At the same time, the annular groove 331 restricts the rotation of the pin, ensuring uniform force distribution and reducing the occurrence of tilting caused by unilateral load. It is suitable for lasts or other workpieces of different thicknesses.

[0047] The implementation principle of the adaptive last clamping fixture in this application embodiment is as follows: the shoe toe support mechanism 1 moves to a preset position and is adjusted to the standard height of the current last. The pin moving mechanism 2 slides laterally to compensate for the offset, driving the pin to align with the pin hole of the last. After the last and the pin are connected and locked, the clamping fixture 42 is activated to achieve rapid coarse positioning and high-precision flexible clamping of the last. This device reduces manual intervention compared with traditional clamping fixtures through graded rotation and multi-plate adaptive design. It is suitable for batch processing scenarios of complex curved surfaces or easily deformable materials, and effectively improves production efficiency.

[0048] Example 2 This application discloses an adaptive last clamping fixture. (Refer to...) Figure 4-6 An adaptive last clamping fixture includes a shoe toe support mechanism 1, a pin moving mechanism 2, and a clamping mechanism 4 arranged sequentially from front to back. The shoe toe support mechanism 1 can move back and forth and rise and fall. The pin moving mechanism 2 is used to move the pins back and forth and left and right to adapt to the offset of the left and right code pin hole positions.

[0049] Specifically, the clamping mechanism 4 includes a clamping cylinder 41 and two clamping fixtures 42 symmetrically arranged at the front end of the clamping cylinder 41. The two clamping fixtures 42 are arranged in a figure-eight shape and are each equipped with a second-order flexible gripper 43. The two second-order flexible grippers 43 are symmetrically arranged on the left and right sides to form a mechanical self-locking effect, which can evenly distribute the clamping force and reduce the damage to the last caused by local stress concentration.

[0050] Furthermore, the first stage is a fractal vise structure, and the second stage is an outer adaptive structure. In this embodiment, the fractal vise structure is composed of a first-stage rotating plate 432 and a first-stage rotating medium 431. The first-stage rotating plate 432 is rotatably connected to the top of the clamping fixture 42 through the first-stage rotating medium 431. The outer adaptive structure is composed of two second-stage rotating plates 434 and a second-stage rotating medium 433. The two second-stage rotating plates 434 are rotatably connected to the inner side of the first-stage rotating plate 432 through the second-stage rotating medium 433.

[0051] Furthermore, in this embodiment, the first-stage rotating medium 431 and the second-stage rotating medium 433 are respectively set as round-headed rivet screws of different sizes, and the diameter of the first-stage rotating medium 431 is larger than the diameter of the second-stage rotating medium 433.

[0052] Therefore, the first-stage rotating medium 431, as the basic clamping unit, usually requires a larger diameter to withstand the basic clamping force, limiting the coarse adjustment range; the second-stage rotating medium 433, responsible for flexible adjustment, has a smaller size to ensure fine angle changes and dynamic compensation capabilities. This differential size design naturally forms a "rigid-flexible" transition, allowing each axis to bear only the optimal load required for its function, reducing overload or strength waste; the rigid connection of the round-headed rivet screw ensures the stability of force transmission, reduces offset during clamping, and the riveting structure itself can also reduce vibration transmission, reduce the fatigue risk at the rotating connection, and synergistically improve the reliability and durability of the fixture.

[0053] The implementation principle of the adaptive last clamping fixture in this application embodiment is as follows: the shoe toe support mechanism 1 moves to a preset position and is adjusted to the standard height of the current last. The pin moving mechanism 2 slides laterally to compensate for the offset, driving the pin to align with the pin hole of the last. After the last and the pin are connected and locked, the clamping fixture 42 is activated to achieve rapid coarse positioning and high-precision flexible clamping of the last. This device reduces manual intervention compared with traditional clamping fixtures through graded rotation and multi-plate adaptive design. It is suitable for batch processing scenarios of complex curved surfaces or easily deformable materials, and effectively improves production efficiency.

[0054] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," "third," and similar terms used in this application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising" or "including" and similar terms mean that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, and do not exclude other elements or objects. "Above," "below," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0055] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An adaptive last clamping fixture, characterized in that, The shoe includes a toe support mechanism (1), a pin moving mechanism (2), and a clamping mechanism (4) arranged sequentially from front to back. The clamping mechanism (4) includes a clamping cylinder (41) and two clamping fixtures (42) symmetrically arranged at the front end of the clamping cylinder (41). The two clamping fixtures (42) are arranged in a figure-eight shape and are respectively provided with a second-order flexible gripper (43). The two second-order flexible grippers (43) are symmetrically arranged from left to right. The first order is a fractal vise structure and the second order is an outer adaptive structure.

2. The adaptive last clamping fixture according to claim 1, characterized in that, The fractal vise structure consists of a first-stage rotating plate (432) and a first-stage rotating medium (431). The first-stage rotating plate (432) is rotatably connected to the top of the clamping fixture (42) via the first-stage rotating medium (431). The outer adaptive structure consists of at least two second-stage rotating plates (434) and a second-stage rotating medium (433). The second-stage rotating plates (434) are rotatably connected to the inner side of the first-stage rotating plate (432) via the second-stage rotating medium (433).

3. The adaptive last clamping fixture according to claim 2, characterized in that, The first-stage rotating medium (431) is configured as a large-sized round-headed crimping screw, and the second-stage rotating medium (433) has a T-slot structure or is configured as a small-sized round-headed crimping screw.

4. The adaptive last clamping fixture according to claim 2, characterized in that, Both the first-stage rotating plate (432) and the second-stage rotating plate (434) have a semi-circular arc structure, and the inner side of the first-stage rotating plate (432) is provided with a rotating groove of a matching shape corresponding to the second-stage rotating plate (434).

5. The adaptive last clamping fixture according to claim 4, characterized in that, A third rotating plate (435) is also fixed inside the second rotating plate. The third rotating plate (435) has a semi-circular arc structure or a block structure.

6. The adaptive last clamping fixture according to claim 1, characterized in that, The pin moving mechanism (2) is provided with a pin fixing pad (3) at the top. The pin fixing pad (3) includes a pad body (31) and a cylindrical pin (32). The head of the cylindrical pin (32) extends downward and is provided with a positioning part (33) coaxial with the pin body. The positioning part (33) is provided with annular grooves (331) spaced along the length direction. The cylindrical pin (32) is fixed to the top of the pad body (31) through the positioning part (33) and the shaft hole of the pad body (31). The tail of the cylindrical pin (32) has a hemispherical structure and is used to connect with the pin hole at the top of the last.

7. The adaptive last clamping fixture according to claim 6, characterized in that, The positioning part (33) is connected to a handle bolt (332) on each of its left and right sides, and the two handle bolts (332) are coaxially arranged. The head of the handle bolt (332) extends out of the side wall of the pad body (31), and its rod is built into the pad body (31) and the height of the cylindrical pin (32) can be adjusted by rotation.

8. The adaptive last clamping fixture according to claim 1, characterized in that, The toe support mechanism (1) can move forward and backward and rise and fall, and the pin moving mechanism (2) is used to move the pin forward and backward and left and right to adapt to the offset of the left and right pin hole positions.

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