Molding shoe hollow-core shoe last forming processing technology

Abstract

The invention relates to a mold shoe hollow shoe last molding processing technology which mainly comprises the following steps: firstly, obtaining three-dimensional data of a sample through a 3D scanning technology; secondly, carrying out product modeling by utilizing computer aided design software, designing an outer blank iron mold and an inner sand core mold, and arranging a guide positioning block and a positioning reference plane on the iron mold; then, a core box for sand mold casting is prepared, sand filling molding and compaction are carried out, molten metal is poured through a pouring gate, and a first-stage shoe tree is taken out after cooling molding; thirdly, the first-stage shoe tree is placed on a special clamping tool, positioning holes in the upper end face are machined, and a second-stage shoe tree is obtained; and finally, placing the second-stage shoe tree on a finished product processing tool, and removing the guide positioning block and the positioning reference plane to obtain a finished shoe tree. A specific clamping tool is adopted in the process, it is guaranteed that the upper end face of the shoe tree is horizontal, machining precision is improved, the process is suitable for shoe trees of different specifications, and production efficiency and product quality are improved.

Description

Technical Field

[0001] The invention specifically relates to a forming process for a hollow last of a molded shoe. Background Art

[0002] A shoe last is a model used to make shoes. Shoe lasts are mainly divided into three categories: wooden lasts, plastic lasts and metal lasts.

[0003] For the metal shoe last, its production and manufacturing method mainly adopts sand casting. First, the shoe mold is designed and manufactured according to customer needs, and the shoe mold is placed between the upper and lower molds, and then sand is filled to shape and compact it. The upper and lower molds are separated, and the shoe mold is taken out. Then the sand core mold is put in, and the upper and lower molds are covered. The molten metal liquid is poured from the casting hole, and the initial stage shoe last is taken out after cooling and forming. Next, the outer surface of the initial stage shoe last is processed, and the required positioning holes are processed at the upper end of the shoe last. For example, the Chinese invention patent document with publication number "CN207444402U" discloses a through-hole structure injection shoe last, and two groups of positioning holes 2 are provided on the shoe last body. Combined with the specification of the public document, Figures 2 to 5 The position of the positioning hole 2 can be clearly seen. These two sets of positioning holes are structures that must be processed in the processing and manufacturing of the shoe last. The role of the positioning holes is to allow the robot arm to be fixed to the shoe last body and realize the automatic operation of the movement of the shoe last body. It is not only for the convenience of processing the shoe last, but also for the later use of the shoe last in the process of producing shoes. The shoe last is not considered to be processed until the positioning holes are processed.

[0004] When processing the positioning holes of the shoe last, it is crucial to ensure that the upper end of the shoe last is exposed and remains horizontal, because any tilt will directly affect the position and direction of the positioning holes. In addition, in order to accurately process two sets of positioning holes, the upper end of the shoe last must not only be horizontal, but also be oriented in a predetermined direction so that reference positioning can be performed.

[0005] In summary, for the production and manufacturing process of metal shoe lasts, how to quickly and accurately process the positioning holes on the shoe lasts and solve the above-mentioned technical problems must be considered. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a hollow shoe last forming process in view of the deficiencies of the above-mentioned prior art.

[0007] To achieve the above object, the present invention provides the following technical solutions: The hollow shoe last forming process is characterized by comprising the following steps: S1, scan the samples provided by customers through 3D scanning technology to obtain three-dimensional data of the samples; S2, using computer-aided design software to model the product according to the three-dimensional data, including a split outer blank iron mold, the inner part of the outer blank iron mold is provided with a hollow sand-filling cavity, and an inner sand core mold with the same structure is designed according to the sand-filling cavity, and the foot-treading surface of the outer blank iron mold is provided with two groups of guide positioning blocks, one group of guide positioning blocks is close to the toe part, and the other group of guide positioning blocks is at the heel, and symmetrical positioning reference planes are respectively provided on both sides of each group of guide positioning blocks, and the positioning reference planes are kept parallel to the upper end surface of the shoe last; S3, prepare a core box for sand casting, the core box is divided into an upper mold and a lower mold which are separated and relatively arranged; put the outer blank iron mold between the upper mold and the lower mold, then fill with sand to shape and compact; open the upper mold and the lower mold, take out the outer blank iron mold, at this time, a shoe last outer blank molding cavity consistent with the structure of the outer blank iron mold is formed between the upper mold and the lower mold; then put the inner sand core mold into the shoe last outer blank molding cavity, the inner sand core mold and the inner wall of the shoe last outer blank molding cavity have the shoe last molding wall thickness, and cover the upper and lower molds; pour the molten metal into the shoe last outer blank molding cavity through the gate, cool and shape; open the mold to take out the molded product, and pour out the inner sand core mold to obtain a first-stage shoe last; S4, placing the first-stage shoe last on a special clamping tool for shoe lasts, processing the upper end surface of the first-stage shoe last, processing the required positioning holes on the upper end surface of the first-stage shoe last, and obtaining the second-stage shoe last; S5, placing the second-stage shoe last on a shoe last finished product processing tool, removing two sets of guide positioning blocks on the foot-treading surface of the second-stage shoe last and the positioning reference planes on both sides of each set of guide positioning blocks, and obtaining a finished shoe last.

[0008] The design points of this technical solution are as follows: First, when modeling in step S2, "two sets of guide positioning blocks and positioning reference planes need to be designed on the foot surface of the outer blank iron mold". The purpose is that when the positioning holes are processed on the upper end surface of the shoe last in step S4, the upper end surface of the special-shaped shoe last can be quickly and accurately guided according to the guide positioning blocks and positioning reference planes to ensure that it is located on the horizontal plane, so as to ensure that the position and direction of the processed positioning holes are accurate. Second, a specific "shoe last special clamping tool" is used to cooperate with the aforementioned guide positioning blocks and positioning reference planes to realize the rapid and accurate processing of the positioning holes on the upper end surface of the shoe last, which is of great help in the actual production process in this field, effectively improving production efficiency, and the shoes produced are more beautiful and practical. Third, after the positioning holes are processed, a specific "finished shoe last processing tooling" is used. The second-stage shoe last is clamped on the tooling using the positioning holes processed previously, and then the "guide positioning block and positioning reference surface" are cut off using the machine tool in the workshop to obtain the finished shoe last. Among them, the "computer-aided design software" mentioned in step S2 refers to three-dimensional design software, such as UG, solidworks, CAD, etc.; the material of the inner sand core mold is different from that of the outer blank iron mold. The inner sand core mold is actually a mold sand composed of silicate (such as quartz sand, talcum powder, etc.) or oxide (such as aluminum, magnesium, etc.), which can maintain a certain structural shape. After the first-stage shoe last is formed, it can be loosened by shaking and other methods, so as to be discharged from the first-stage shoe last.

[0009] The above-mentioned hollow shoe last forming process can be further configured as follows: during modeling in step S2, several groups of positioning rods are designed on the periphery of the inner sand core mold, the length of the positioning rods is consistent with the thickness of the shoe last forming wall, and sand discharge holes are designed at the heel of the outer blank iron mold.

[0010] By adopting the above technical solution, when the inner sand core mold is placed in the outer blank molding cavity of the shoe last, the end of the positioning rod contacts the inner wall of the outer blank molding cavity of the shoe last, thereby positioning the inner sand core mold, ensuring that the inner sand mold is stably maintained inside the outer blank molding cavity of the shoe last, and there is a gap between the two with the thickness of the shoe last molding wall, so that after the molten metal is injected, it can be cooled to form a first-stage shoe last.

[0011] The above-mentioned mold shoe hollow last forming processing technology can be further configured as follows: the shoe last special clamping tooling includes a relatively distributed shoe last fixed guide plate, a shoe last movable guide plate, a last heel limit block fixed on the shoe last fixed guide plate, and a last limit block fixed on the shoe last movable guide plate, the shoe last fixed guide plate is fixed on the frame, and the shoe last fixed guide plate is provided with a left longitudinal center positioning groove on one side facing the shoe last movable guide plate, and the left longitudinal center positioning groove is open towards the end of the shoe last movable guide plate. A right longitudinal center positioning groove is provided on the side of the movable guide plate of the shoe last facing the fixed guide plate of the shoe last, and the end of the right longitudinal center positioning groove facing the fixed guide plate of the shoe last is open. The movable guide plate of the shoe last is linked with a linear motion mechanism, and the linear motion mechanism can drive the movable guide plate of the shoe last to reciprocate toward the fixed guide plate of the shoe last. The fixed guide plate of the shoe last is linked with a centering positioning device capable of clamping the top of the shoe last, and the movable guide plate of the shoe last is linked with a flipping positioning device capable of pressing the shoe last.

[0012] By adopting the above technical solution, the linear motion mechanism drives the movable guide plate of the shoe last to move to an initial position, so that the spacing between the fixed guide plate of the shoe last and the movable guide plate of the shoe last is large enough to accommodate the insertion of a first-stage shoe last. The foot-treading surface of the first-stage shoe last is facing the two shoe last guide plates, and the two groups of guide positioning blocks are respectively inserted into the left longitudinal center positioning groove and the right longitudinal center positioning groove to ensure that the placement direction of the first-stage shoe last is correct and unique. Furthermore, the positioning reference planes on both sides of each group of guide positioning blocks on the first-stage shoe last are respectively in contact with the planes of the fixed guide plate of the shoe last and the movable guide plate of the shoe last, so as to realize the positioning of the upper end surface of the first-stage shoe last, ensure that it is located in the horizontal plane, and can accurately perform reference positioning, so as to ensure that the position and direction of the processed positioning holes are accurate. The centering positioning device clamps the upper part of the first-stage shoe last and centers the upper part of the first-stage shoe last. Once the first-stage shoe last is correctly guided and positioned, the linear motion mechanism starts, driving the movable guide plate of the shoe last to move to the left until the movable guide plate of the shoe last reaches the predetermined position. Then the flip positioning device presses the first-stage shoe last. At this time, the position and direction of the first-stage shoe last are firmly locked, and the positioning hole is processed using a cutting tool (ordinary machine tools can be used). Furthermore, the linear motion mechanism drives the movable guide plate of the shoe last to move, which can adapt to shoe lasts of different specifications and types, and expand the adaptability of the shoe last plane guiding and positioning mechanism. In summary, the special clamping tool for the shoe last provided by this solution can ensure that the upper end of the shoe last remains horizontal, ensure that the shoe last is placed in the correct direction, stably fix the shoe last, effectively prevent the displacement of the shoe last during processing, ensure the accuracy of the positioning hole, and can also adapt to shoe lasts of different specifications and types.

[0013] The above-mentioned mold shoe hollow last forming processing technology can be further configured as follows: the centering positioning device includes a centering frame and positive and negative threaded screws rotatably mounted on the centering frame at both ends through bearings, the centering frame is detachably mounted on the shoe last fixing guide plate through screws, the positive and negative threaded screws are sequentially provided with positive threaded screw segments and negative threaded screw segments along their own axial direction, the positive threaded screw segments and negative threaded screw segments are symmetrically arranged with each other, the positive threaded screw segments are threadedly linked with a positive threaded nut sleeve, and the negative threaded screw segments are threadedly linked with a A reverse thread nut sleeve, the forward thread nut sleeve is linked to a forward thread centering block, the reverse thread nut sleeve is linked to a reverse thread centering block, the forward and reverse thread screws are linked to a rotating drive mechanism capable of driving the forward and reverse thread screws to rotate, the rotating drive mechanism includes a centering drive driven sprocket linked to the ends of the forward and reverse thread screws, the centering drive driven sprocket is linked to a centering drive active sprocket through a chain, the centering drive active sprocket is linked to a centering hydraulic motor, and the body of the centering hydraulic motor is installed on a centering frame.

[0014] With the above technical solution, the rotary drive mechanism is started to drive the screw to rotate. As the screw rotates, the positive thread nut sleeve and the negative thread nut sleeve move on the positive thread screw section and the negative thread screw section respectively. Due to the opposite thread directions, the two nut sleeves will move in opposite directions. The positive thread nut sleeve and the negative thread nut sleeve are respectively linked with the positive thread centering block and the negative thread centering block. Therefore, when the nut sleeve moves, the centering block will also move accordingly. When the positive and negative thread screws rotate to make the two nut sleeves move toward each other, the two centering blocks will also approach each other until the top of the first-stage shoe last is clamped and positioned in the middle of the shoe last fixed guide plate. Conversely, when the positive and negative thread screws rotate to make the two nut sleeves move away from each other, the two centering blocks will separate from each other and release the shoe last. Through the centering and positioning device designed in this application, the upper end of the first-stage shoe last is exposed, which can facilitate the processing of the positioning hole. At the same time, the structure is simple, the cost of the entire mechanism is low, and rapid centering and clamping can be achieved.

[0015] The above-mentioned mold shoe hollow last forming processing technology can be further set as: the flip positioning device includes a clamping body and a support frame, the support frame is detachably mounted on the movable guide plate of the shoe last by screws, one end of the clamping body is linked to a rotating shaft, both ends of the rotating shaft are hinged to the support frame by bearings, the end of the rotating shaft is linked to a second driven sprocket, the second driven sprocket is linked to a second driving sprocket through a chain, the second driving sprocket is linked to a flip hydraulic motor, and the flip hydraulic motor is installed on the support frame.

[0016] By adopting the above technical solution, when the flip positioning device follows the movable guide plate of the shoe last and moves toward the shoe last until it is close to the shoe last, the flip hydraulic motor drives the second active sprocket to rotate, and the chain drives the second driven sprocket to rotate synchronously, thereby driving the rotating shaft to rotate, and one end of the clamping body will rotate accordingly until the other end of the clamping body flips to the shoe last, pressing the two sides of the shoe last to fix the shoe last. The clamping body directly acts on the shoe last to position or release it, which greatly saves space compared to the traditional linear movement method. Furthermore, the use of a flip hydraulic motor not only has a fast response speed, but also can change the flip angle of the clamping body according to actual needs to adapt to shoe lasts of different specifications and types.

[0017] The above-mentioned mold shoe hollow last forming processing technology can be further set as follows: the left longitudinal center positioning groove and the right longitudinal center positioning groove are parallel to each other, and the two are on the same straight line trajectory; the upper end surface of the shoe last fixed guide plate is the left positioning reference plane, and the upper end surface of the shoe last movable guide plate is the right positioning reference plane, and the left positioning reference plane and the right positioning reference plane are parallel to each other and on the same horizontal plane.

[0018] By adopting the above technical solution, "the left longitudinal center positioning groove and the right longitudinal center positioning groove are parallel to each other, and the two are located on the same straight line track", it is ensured that the first-stage shoe last can move along a stable, straight path during the insertion process, avoiding the first-stage shoe last from being offset or tilted during the insertion process, thereby improving the precision of the guide and the accuracy of positioning. Furthermore, the left positioning reference plane and the right positioning reference plane are located on the same horizontal plane and on the same plane, ensuring that the upper end face of the first-stage shoe last (this is mainly because the positioning reference planes on both sides of the guide positioning block are parallel to the upper end face of the first-stage shoe last) is accurately positioned in the horizontal direction, avoiding the positioning error caused by the inconsistent height of the two guide plates, and further improving the positioning accuracy of the shoe last.

[0019] The above-mentioned mold shoe hollow last forming processing technology can be further set as follows: the linear motion mechanism includes a lifting block fixed to the bottom of the shoe last movable guide plate by screws, the lifting block is linked to a third slider, the third slider is slidably matched with a second slide rail, the second slide rail is fixed on the frame and the second slide rail is arranged parallel to the right longitudinal center positioning groove, a transmission block is fixed under the shoe last movable guide plate, the transmission block is linked to a cylinder, the body of the cylinder is fixed on the frame, and the cylinder can drive the shoe last movable guide plate to reciprocate axially along the second slide rail through the transmission block.

[0020] With the above technical solution, when the first-stage shoe last is inserted into the fixed guide plate of the shoe last and the movable guide plate of the shoe last through two sets of guide positioning blocks, the cylinder pushes the movable guide plate of the shoe last to move axially along the slide rail through the transmission block. Since the slide rail is arranged parallel to the right longitudinal center positioning groove, the movable guide plate of the shoe last maintains a stable direction during the movement until the centering positioning device and the flip positioning device clamp the shoe last, which is convenient for subsequent processing operations. After the processing is completed, the centering positioning device and the flip positioning device withdraw, and the cylinder drives the movable guide plate of the shoe last to move in the opposite direction along the slide rail to release the first-stage shoe last.

[0021] The above-mentioned mold shoe hollow last forming processing technology can be further set as: the shoe last finished product processing tooling includes two groups of rotating seats fixedly installed on the frame, and cutting positioning plates distributed between the two groups of rotating seats, and both ends of the cutting positioning plates are linked with rotating blocks, and the rotating blocks can be rotatably installed on the rotating seats. One group of rotating blocks is linked with a shoe last positioning hydraulic motor, and the outer periphery of the rotating blocks is evenly distributed with scale marks, and the rotating seat is provided with a directional arrow for pointing to the scale marks.

[0022] By adopting the above technical solution, the second-stage shoe last can be fixed on the cutting positioning plate by machining a clamping positioning hole corresponding to the positioning hole of the upper part of the second-stage shoe last on the cutting positioning plate, and the foot-treading surface is exposed. Then, the "guide positioning block and positioning reference surface" of the foot-treading surface can be cut and removed by using a cutting tool (ordinary machine tools can be used). Among them, the shoe last positioning hydraulic motor is used to adjust the angle of the cutting positioning plate according to actual conditions, so as to adapt to different shoe lasts or working conditions, so as to more efficiently and accurately remove the "guide positioning block and positioning reference surface" to obtain a finished shoe last.

[0023] The present invention is further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of an outer blank iron mold according to an embodiment of the present invention; Figure 2 A schematic diagram of an inner sand core mold according to an embodiment of the present invention; Figure 3 Schematic diagram of a shoe last at a first stage according to an embodiment of the present invention; Figure 4 Schematic diagram of a two-stage shoe last according to an embodiment of the present invention; Figure 5 Schematic diagram of a finished shoe last according to an embodiment of the present invention; Figure 6 This is a schematic diagram of a special clamping tool for a shoe last according to an embodiment of the present invention; Figure 7 It is a schematic diagram of a shoe last being clamped on a special clamping tool for a shoe last in a first stage of an embodiment of the present invention; Figure 8A schematic diagram of a flip positioning device according to an embodiment of the present invention; Fig. 9 This is a schematic diagram of the linkage between the shoe last and the flip positioning device in the first stage of an embodiment of the present invention; Fig.10 Schematic diagram of the explosion of the flip positioning device and the linear motion mechanism according to the embodiment of the present invention Fig.11 It is an exploded schematic diagram of a centering and positioning device according to an embodiment of the present invention; Fig.12 This is a schematic diagram of the linkage between the shoe last and the centering positioning device in the first stage of an embodiment of the present invention; Fig.13 Schematic diagram of a shoe last fixed guide plate and a shoe last movable guide plate according to an embodiment of the present invention; Fig.14 It is a schematic diagram of a tooling for processing a finished shoe last according to an embodiment of the present invention; Fig.15 It is a schematic diagram of the guide positioning block and the positioning reference plane according to an embodiment of the present invention.

[0025] Label notes: finished shoe last a, guide positioning block a1, positioning reference plane a2, outer blank iron mold a3, inner sand core mold a4, positioning rod a5, sand discharge hole a6, first-stage shoe last a7, second-stage shoe last a8, positioning hole a9; shoe last movable guide plate b, right longitudinal center positioning groove b1, right positioning reference plane b2; linear motion mechanism c, lifting block c1, third slider c2, second slide rail c3, transmission block c4, cylinder c5; centering positioning device d, centering frame d1, positive thread screw section d2, negative thread screw section d3, positive thread nut sleeve d4, negative thread nut sleeve d5, positive thread centering block d6, negative thread centering block d7, centering drive driven sprocket d8 , centering driving sprocket d9, centering hydraulic motor d10, first linkage block d11, first slider d12, first slide rail d13, second linkage block d14, second slider d15; flip positioning device e, clamping body e1, support frame e2, rotating shaft e3, second driven sprocket e4, arc chamfer e5, flip hydraulic motor e6, U-shaped groove e7, V-shaped welt e8; last heel limit block f, last head limit block g; shoe last fixed guide plate h, left longitudinal center positioning groove h1, left positioning reference plane h2; shoe last finished product processing tooling k, rotating seat k1, rotating block k2, shoe last positioning hydraulic motor k3, scale mark k4, cutting positioning plate k5. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] like Figures 1 to 15 As shown, the hollow shoe last forming process includes the following steps: S1: Scan the sample provided by the customer through 3D scanning technology to obtain the three-dimensional data of the sample. Among them, the scanner includes but is not limited to laser scanner, structured light scanner and white light scanner.

[0028] S2: Product modeling is performed using computer-aided design software based on three-dimensional data, including a split outer blank iron mold a3, the inner part of which is provided with a hollow sand-filling cavity, and an inner sand core mold a4 with the same structure is designed based on the sand-filling cavity. "Computer-aided design software" refers to three-dimensional design software, such as UG, solidworks, CAD, etc.

[0029] Several groups of positioning rods a5 are designed on the periphery of the inner sand core mold a4, and the length of the positioning rods a5 is consistent with the thickness of the shoe last molding wall, and sand discharge holes a6 are designed at the heel of the outer blank iron mold a3. When the inner sand core mold a4 is placed in the outer blank molding cavity of the shoe last, the end of the positioning rod a5 contacts the inner wall of the outer blank molding cavity of the shoe last, thereby positioning the inner sand core mold a4, ensuring that the inner sand mold is stably maintained inside the outer blank molding cavity of the shoe last, and there is a gap between the two with the thickness of the shoe last molding wall for molding the shoe last.

[0030] The foot-treading surface of the outer blank iron mold a3 is provided with two groups of guide positioning blocks a1, one group of guide positioning blocks a1 is close to the toe part, and the other group of guide positioning blocks a1 is at the heel. Both sides of each group of guide positioning blocks a1 are respectively provided with symmetrical positioning reference planes a2, and the positioning reference planes a2 and the upper end surface of the shoe last are kept parallel to each other. The purpose is that when the positioning hole a9 is processed on the upper end surface of the shoe last in step S4, the upper end surface of the special-shaped shoe last can be quickly and accurately guided according to the guide positioning blocks a1 and the positioning reference plane a2 to ensure that it is located on the horizontal plane, so as to ensure that the position and direction of the processed positioning hole a9 are accurate.

[0031] S3: prepare the upper mold and lower mold for sand casting; put the outer blank iron mold a3 between the upper mold and the lower mold, then fill with sand to shape and compact; open the upper mold and the lower mold, take out the outer blank iron mold a3, at this time, a shoe last outer blank molding cavity consistent with the structure of the outer blank iron mold a3 is formed between the upper mold and the lower mold; then put the inner sand core mold a4 into the shoe last outer blank molding cavity, the inner sand core mold a4 and the inner wall of the shoe last outer blank molding cavity have the shoe last molding wall thickness, and cover the upper and lower molds; pour the molten metal into the shoe last outer blank molding cavity through the gate, cool and shape; open the mold to take out the molded product, and pour out the inner sand core mold a4 to obtain a first-stage shoe last a7.

[0032] S4: placing the first-stage shoe last a7 on a special clamping tool for shoe lasts, processing the upper end surface of the first-stage shoe last a7, processing the required positioning holes a9 on the upper end surface of the first-stage shoe last a7, and obtaining the second-stage shoe last a8.

[0033] Among them, the special clamping tooling for shoe lasts includes a relatively distributed shoe last fixed guide plate h and a shoe last movable guide plate b. The shoe last fixed guide plate h is fixed on the frame, and a left longitudinal center positioning groove h1 is provided on the side of the shoe last fixed guide plate h facing the shoe last movable guide plate b, and the left longitudinal center positioning groove h1 is open toward the end of the shoe last movable guide plate b, and a right longitudinal center positioning groove b1 is open toward the end of the shoe last fixed guide plate h. The shoe last movable guide plate b is linked to a linear motion mechanism c, which can drive the shoe last movable guide plate b to reciprocate toward the shoe last fixed guide plate h. The shoe last fixed guide plate h is linked to a centering positioning device d that can clamp the top of a first-stage shoe last a7, and the shoe last movable guide plate b is linked to a flip positioning device e that can press the first-stage shoe last a7.

[0034] The left longitudinal center positioning groove h1 and the right longitudinal center positioning groove b1 are parallel to each other and are on the same straight line trajectory, ensuring that the first-stage shoe last a7 can move along a stable, straight path during the insertion process, avoiding the first-stage shoe last a7 from deflecting or tilting during the insertion process, thereby improving the guiding precision and positioning accuracy.

[0035] The upper end surface of the shoe last fixed guide plate h is the left positioning reference plane h2, and the upper end surface of the shoe last movable guide plate b is the right positioning reference plane b2. The left positioning reference plane h2 and the right positioning reference plane b2 are parallel to each other and are on the same horizontal plane. This ensures that the upper end surface of the first-stage shoe last a7 (this is mainly because the positioning reference planes a2 on both sides of the guide positioning block a1 are parallel to the upper end surface of the first-stage shoe last a7) is accurately positioned in the horizontal direction, avoiding positioning errors caused by inconsistent heights of the two guide plates, and further improving the positioning accuracy of the first-stage shoe last a7.

[0036] The linear motion mechanism c includes a lifting block c1 fixed by screws below the last movable guide plate b, the lifting block c1 is linked to a third slider c2, the third slider c2 is slidably matched with a second slide rail c3, the second slide rail c3 is fixed on the frame and the second slide rail c3 is arranged parallel to the right longitudinal center positioning groove b1, a transmission block c4 is fixed below the last movable guide plate b, the transmission block c4 is linked to a cylinder c5, the body of the cylinder c5 is fixed on the frame, and the cylinder c5 can drive the last movable guide plate b to reciprocate along the axial direction of the second slide rail c3 through the transmission block c4. When the first-stage shoe last a7 is respectively inserted into the last fixed guide plate h and the last movable guide plate b through two sets of guide positioning blocks a1, the cylinder c5 pushes the last movable guide plate b to move along the axial direction of the slide rail through the transmission block c4. Since the slide rail is arranged parallel to the right longitudinal center positioning groove b1, the shoe last movable guide plate b maintains a stable direction during the movement until the centering positioning device d and the flip positioning device e clamp the first-stage shoe last a7, which is convenient for subsequent processing operations. After the processing is completed, the centering positioning device d and the flip positioning device e withdraw, and the cylinder c5 drives the shoe last movable guide plate b to move in the opposite direction along the slide rail to release the first-stage shoe last a7.

[0037] The centering and positioning device d comprises a centering frame d1 and a forward and reverse threaded screw rod rotatably mounted on the centering frame d1 at both ends through bearings; the centering frame d1 is detachably mounted on a shoe last fixing guide plate h through screws; the forward and reverse threaded screw rods are sequentially provided with a forward threaded screw rod segment d2 and a reverse threaded screw rod segment d3 along their own axial direction; the forward threaded screw rod segment d2 and the reverse threaded screw rod segment d3 are symmetrically arranged with each other; the forward threaded screw rod segment d2 is threadedly linked with a forward threaded nut sleeve d4; the reverse threaded screw segment d3 is threadedly linked with a reverse threaded nut sleeve d5; the forward threaded nut sleeve d4 is linked with a forward threaded centering block d6; the reverse threaded nut sleeve d5 is linked with a reverse threaded centering block d7; the forward and reverse threaded screw rods are linked with a rotating drive mechanism capable of driving the forward and reverse threaded screw rods to rotate; when the rotating drive mechanism drives the forward and reverse threaded screw rods to rotate, the forward threaded centering block d6 and the reverse threaded centering block d7 can approach or separate from each other. The rotary drive mechanism starts, driving the positive and negative threaded screws to rotate. As the positive and negative threaded screws rotate, the positive threaded nut sleeve d4 and the negative threaded nut sleeve d5 move on the positive threaded screw segment d2 and the negative threaded screw segment d3 respectively. Since the thread directions are opposite (the positive threaded screw segment d2 and the negative threaded screw segment d3 are symmetrically arranged), the two nut sleeves will move in opposite directions, and the positive threaded nut sleeve d4 and the negative threaded nut sleeve d5 are respectively linked with the positive threaded centering block d6 and the negative threaded centering block d7. Therefore, when the nut sleeve moves, the centering block will also move accordingly. When the positive and negative threaded screws rotate to cause the two nut sleeves to move toward each other, the two centering blocks will also approach each other until the top of the first-stage shoe last a7 is clamped and positioned in the middle of the shoe last fixed guide plate h. Conversely, when the positive and negative threaded screws rotate to cause the two nut sleeves to move away from each other, the two centering blocks will separate from each other and release the first-stage shoe last a7. Through the centering and positioning device d designed in the present application, the upper end of the shoe last a7 is exposed at a stage, which can facilitate the processing of the positioning hole a9. At the same time, the structure is simple, the cost of the entire mechanism is low, and rapid centering and clamping can be achieved.

[0038] A last heel limit block f is provided below the positive and negative threaded rods, and the last heel limit block f is detachably connected to the shoe last fixing guide plate h through screws. The last heel limit block f positions the heel part of the first-stage shoe last a7, thereby preliminarily positioning the first-stage shoe last a7 in the correct position. The last heel limit block f cooperates with the two sets of centering guide positioning blocks a1 to achieve multi-directional positioning of the first-stage shoe last a7. The last heel limit block f is detachably connected to the centering frame d1 through screws, so that the last heel limit block f can be quickly disassembled and assembled to adapt to first-stage shoe lasts a7 of different specifications and types.

[0039] The rotary drive mechanism includes a centering driven sprocket d8 linked with the ends of the forward and reverse screw rods, and the centering driven sprocket d8 is linked with the centering driving sprocket d9 through a chain (not shown in the figure), and the centering driving sprocket d9 is linked with the centering hydraulic motor d10, and the body of the centering hydraulic motor d10 is installed on the centering frame d1. When the centering positioning device d is working, the centering hydraulic motor d10 drives the centering driving sprocket d9 to rotate, and the centering driving sprocket d9 is linked with the centering driven sprocket d8 through the chain. When the centering driving sprocket d9 rotates, the chain drives the centering driven sprocket d8 to rotate synchronously, thereby driving the forward and reverse screw rods to rotate, and the two sets of centering blocks approach each other to clamp and center the upper part of the first-stage shoe last a7.

[0040] The outer periphery of the positive thread nut sleeve d4 is provided with a first linkage block d11, one side of the first linkage block d11 is detachably connected to the first slider d12 by screws, the first slider d12 is slidably matched with the first slide rail d13, the first slide rail d13 is fixed on the centering frame d1 and the first slide rail d13 is parallel to the positive and negative thread screws, and the other side of the first linkage block d11 is detachably connected to the positive thread centering block d6 by screws; the outer periphery of the negative thread nut sleeve d5 is provided with a second linkage block d14, one side of the second linkage block d14 is detachably connected to the second slider d15 by screws, the second slider d15 is slidably matched with the first slide rail d13, and the other side of the second linkage block d14 is detachably connected to the negative thread centering block d7 by screws. The linkage block is an intermediate component connecting the nut sleeve and the slider, and the linkage block can convert the movement of the nut sleeve into the movement of the slider. At the same time, the linkage block is also detachably connected to the centering block by screws, which facilitates the installation and disassembly of the centering block. The first slide rail d13, the first slider d12 and the second slider d15 are used to reduce the stress on the positive and negative screw rods and improve the movement stability of the two sets of centering blocks.

[0041] The flip positioning device e includes a clamping body e1 and a support frame e2. The support frame e2 is detachably mounted on the movable guide plate b of the shoe last by screws. One end of the clamping body e1 is linked to a rotating shaft e3. Both ends of the rotating shaft e3 are hinged to the support frame e2 by bearings. The end of the rotating shaft e3 is linked to a second driven sprocket e4. The second driven sprocket e4 is linked to a second driving sprocket through a chain (not shown in the figure). The second driving sprocket is linked to a flip hydraulic motor e6. The flip hydraulic motor e6 is installed on the support frame e2. When the flip positioning device e follows the shoe last movable guide plate b and moves toward the first-stage shoe last a7 until it is close to the first-stage shoe last a7, the flip hydraulic motor e6 drives the second active sprocket to rotate, and the chain drives the second driven sprocket e4 to rotate synchronously, thereby driving the rotating shaft e3 to rotate, and one end of the clamping body e1 will rotate accordingly until the other end of the clamping body e1 flips to the first-stage shoe last a7, and the two sides of the first-stage shoe last a7 are pressed to fix the first-stage shoe last a7. The clamping body e1 directly acts on the first-stage shoe last a7 to position or release it, which greatly saves space compared to the traditional linear movement method. Furthermore, the use of the flip hydraulic motor e6 not only has a fast response speed, but also can change the flip angle of the clamping body e1 according to actual needs to adapt to first-stage shoe lasts a7 of different specifications and types.

[0042] A last limit block g is provided below the clamping body e1, and the two sides of the last limit block g are detachably connected to the two sides of the last movable guide plate b by screws. The last limit block g positions the front end of the first-stage shoe last a7, thereby preliminarily positioning the first-stage shoe last a7 in the correct position. While the clamping body e1 clamps the first-stage shoe last a7, the last limit block g continues to play a supporting and limiting role, ensuring that the first-stage shoe last a7 will not shake or shift during the positioning process, greatly improving the stability and accuracy of the positioning of the first-stage shoe last a7. Furthermore, the two sides of the last limit block g are detachably connected to the two sides of the last movable guide plate b by screws, which facilitates the replacement of the last limit block g to meet the positioning requirements of different first-stage shoe lasts a7.

[0043] The other end of the clamping body e1 is provided with a U-shaped groove e7, and the end of the U-shaped groove e7 away from the rotating shaft e3 is open, and the other end of the U-shaped groove e7 is provided with a symmetrically distributed V-shaped welt e8, and the open end of the U-shaped groove e7 of the clamping body e1 is provided with an arc chamfer e5. The U-shaped groove e7 is used to accommodate and position the first-stage shoe last a7, and an opening is provided at the end of the U-shaped groove e7, so that the clamping body e1 can easily enter or exit the first-stage shoe last a7. The V-shaped welt e8 is convenient to adapt to the arc of the front side of the first-stage shoe last a7. The arc chamfer e5 prevents the clamping body e1 from scratching the hands, and plays a protective role for the operator.

[0044] The specific operation method of the shoe last special clamping tool is as follows: First, the linear motion mechanism c drives the movable guide plate b of the shoe last to move to an initial position, so that the distance between the fixed guide plate h of the shoe last and the movable guide plate b of the shoe last is large enough to accommodate the insertion of a first-stage shoe last a7. Secondly, the foot-treading surface of the first-stage shoe last a7 faces the two shoe last guide plates, and the two sets of guide positioning blocks a1 are respectively inserted into the left longitudinal center positioning groove h1 and the right longitudinal center positioning groove b1 to ensure that the placement direction of the first-stage shoe last a7 is correct and unique. Furthermore, the first-stage shoe last a7 moves to its heel and contacts the last heel limit block f, and the centering positioning device d clamps the upper part of the first-stage shoe last a7 and centers the upper part of the first-stage shoe last a7. Finally, the linear motion mechanism c is started, driving the movable guide plate b of the shoe last to move to the left until the movable guide plate b of the shoe last reaches the predetermined position (that is, the toe of the first-stage shoe last a7 contacts the last head limit block g). Then, the positioning device e is turned over to press the first-stage shoe last a7, ensuring that the positioning reference planes a2 on both sides of each group of guide positioning blocks a1 on the first-stage shoe last a7 are in contact with the planes of the shoe last fixed guide plate h and the shoe last movable guide plate b. At this time, the position and direction of the first-stage shoe last a7 are firmly locked, thereby realizing the positioning of the upper end surface of the first-stage shoe last a7, ensuring its horizontal plane, and being able to accurately perform reference positioning, so that the position and direction of the processed positioning holes a9 are accurate.

[0045] S5: Place the second-stage shoe last a8 on the shoe last finished product processing tool k, remove the two groups of guide positioning blocks a1 on the foot surface of the second-stage shoe last a8 and the positioning reference planes a2 on both sides of each group of guide positioning blocks a1, and obtain the finished shoe last a.

[0046] The shoe last finished product processing tool k includes two groups of rotating seats k1 fixedly mounted on the frame, and cutting positioning plates k5 distributed between the two groups of rotating seats k1. Both ends of the cutting positioning plates k5 are linked with rotating blocks k2, and the rotating blocks k2 can be rotatably mounted on the rotating seats k1. One group of rotating blocks k2 is linked with a shoe last positioning hydraulic motor k3. The outer periphery of the rotating blocks k2 is evenly distributed with scale marks k4, and the rotating seats k1 are provided with a directional arrow for pointing to the scale mark k4. By machining a clamping positioning hole a9 corresponding to the upper end positioning hole a9 of the second-stage shoe last a8 on the cutting positioning plate k5, the second-stage shoe last a8 can be fixed on the cutting positioning plate k5, and the foot surface is exposed. Then, the "guide positioning block a1 and positioning reference surface" of the foot surface can be cut and removed by using a cutting tool (ordinary machine tools can be used). Among them, the shoe last positioning hydraulic motor k3 is used to adjust the angle of the cutting positioning plate k5 according to actual conditions, so as to adapt to different shoe lasts or working conditions, so as to more efficiently and accurately remove the "guide positioning block a1, positioning reference surface" to obtain the finished shoe last a.

[0047] Among them, the first-stage shoe last a7 has no positioning hole a9 processed on the upper end. The first-stage shoe last a7 is clamped on the shoe last special clamping fixture. The positioning hole a9 is processed on the upper end of the first-stage shoe last a7 using a cutting tool (ordinary machine tools are available), and the second-stage shoe last a8 (with positioning hole a9) is obtained. The second-stage shoe last a8 is clamped on the shoe last finished product processing fixture k, and the cutting angle is adjusted according to the actual situation. The "guide positioning block a1 and positioning reference surface" on the foot surface of the second-stage shoe last a8 can be cut and removed using a cutting tool (ordinary machine tools are available), and the finished shoe last a is obtained. The inner sand core mold a4 is made of a different material from the outer blank iron mold a3. The inner sand core mold a4 is actually mold sand composed of silicates (such as quartz sand, talcum powder, etc.) or oxides (such as aluminum, magnesium, etc.), which can maintain a certain structural shape. After the first-stage shoe last a7 is formed, it can be loosened by shaking and the like, and thus discharged from the first-stage shoe last a7.

[0048] The key points of the hollow shoe last forming process provided in this embodiment are as follows: First, when modeling in step S2, "the foot-treading surface of the outer blank iron mold a3 needs to be designed with two sets of guide positioning blocks a1 and positioning reference plane a2", the purpose of which is that when the positioning hole a9 is processed on the upper end face of the shoe last in step S4, the upper end face of the special-shaped shoe last can be quickly and accurately guided according to the guide positioning blocks a1 and positioning reference plane a2 to ensure that it is located on the horizontal plane, so as to ensure that the position and direction of the processed positioning hole a9 are accurate. Second, a specific "shoe last special clamping tool" is used, which cooperates with the aforementioned guide positioning blocks a1 and positioning reference plane to realize the rapid and accurate processing of the positioning hole a9 on the upper end face of the shoe last, which is of great help in the actual production process in this field, effectively improves production efficiency, and produces shoes that are more beautiful and practical. Third, after the positioning hole a9 is processed, a specific "finished shoe last processing tool k" is used. The second-stage shoe last a8 is clamped on the tool using the positioning hole a9 processed previously, and then the "guide positioning block a1 and positioning reference surface" are cut off using the machine tool in the workshop to obtain the finished shoe last.

Claims

1. The hollow shoe last forming process is characterized by: The following steps are included: S1, scan the samples provided by customers through 3D scanning technology to obtain three-dimensional data of the samples; S2, using computer-aided design software to model the product according to the three-dimensional data, including a split outer blank iron mold, the inner part of the outer blank iron mold is provided with a hollow sand-filling cavity, and an inner sand core mold with the same structure is designed according to the sand-filling cavity, and the foot-treading surface of the outer blank iron mold is provided with two groups of guide positioning blocks, one group of guide positioning blocks is close to the toe part, and the other group of guide positioning blocks is at the heel, and symmetrical positioning reference planes are respectively provided on both sides of each group of guide positioning blocks, and the positioning reference planes are kept parallel to the upper end surface of the shoe last; S3, prepare a core box for sand casting, the core box is divided into an upper mold and a lower mold which are separated and relatively arranged; put the outer blank iron mold between the upper mold and the lower mold, then fill with sand to shape and compact; open the upper mold and the lower mold, take out the outer blank iron mold, at this time, a shoe last outer blank molding cavity consistent with the structure of the outer blank iron mold is formed between the upper mold and the lower mold; then put the inner sand core mold into the shoe last outer blank molding cavity, the inner sand core mold and the inner wall of the shoe last outer blank molding cavity have the shoe last molding wall thickness, and cover the upper and lower molds; pour the molten metal into the shoe last outer blank molding cavity through the gate, cool and shape; open the mold to take out the molded product, and pour out the inner sand core mold to obtain a first-stage shoe last; S4, placing the first-stage shoe last on a special clamping tool for shoe lasts, processing the upper end surface of the first-stage shoe last, processing the required positioning holes on the upper end surface of the first-stage shoe last, and obtaining the second-stage shoe last; S5, placing the second-stage shoe last on a shoe last finished product processing tool, removing two sets of guide positioning blocks on the foot surface of the second-stage shoe last and the positioning reference planes on both sides of each set of guide positioning blocks, and obtaining a finished shoe last.

2. The hollow last forming process for molded shoes according to claim 1, characterized in that: During modeling in step S2, several groups of positioning rods are designed on the periphery of the inner sand core mold, the length of the positioning rods being consistent with the thickness of the shoe last molding wall, and sand discharge holes are designed at the heel of the outer blank iron mold.

3. The hollow last forming process of a molded shoe according to claim 1 or 2, characterized in that: The shoe last special clamping tool comprises a relatively distributed shoe last fixed guide plate, a shoe last movable guide plate, a last heel limit block fixed on the shoe last fixed guide plate, and a last head limit block fixed on the shoe last movable guide plate. The shoe last fixed guide plate is fixed on the frame. A left longitudinal center positioning groove is provided on the side of the shoe last fixed guide plate facing the shoe last movable guide plate. The end of the left longitudinal center positioning groove facing the shoe last movable guide plate is open. The shoe last movable guide plate faces A right longitudinal center positioning groove is provided on one side of the shoe last fixed guide plate, and the right longitudinal center positioning groove is open at the end facing the shoe last fixed guide plate. The shoe last movable guide plate is linked with a linear motion mechanism, and the linear motion mechanism can drive the shoe last movable guide plate to reciprocate toward the shoe last fixed guide plate. The shoe last fixed guide plate is linked with a centering positioning device capable of clamping the top of the shoe last, and the shoe last movable guide plate is linked with a flipping positioning device capable of pressing the shoe last.

4. The hollow last forming process for shoe molds according to claim 3 is characterized in that: The centering positioning device includes a centering frame and a positive and negative threaded screw rods rotatably mounted on the centering frame at both ends through bearings, the centering frame is detachably mounted on the shoe last fixing guide plate through screws, the positive and negative threaded screw rods are sequentially provided with a positive threaded screw rod segment and a negative threaded screw rod segment along their own axial direction, the positive threaded screw rod segment and the negative threaded screw rod segment are symmetrically arranged with each other, the positive threaded screw rod segment is threadedly linked with a positive threaded nut sleeve, the negative threaded screw rod segment is threadedly linked with a negative threaded nut sleeve, the positive threaded nut sleeve is linked with a positive threaded centering block, the negative threaded nut sleeve is linked with a negative threaded centering block, the positive and negative threaded screw rods are linked with a rotating drive mechanism capable of driving the positive and negative threaded screw rods to rotate, the rotating drive mechanism includes a centering drive driven sprocket linked with the ends of the positive and negative threaded screw rods, the centering drive driven sprocket is linked with a centering drive active sprocket through a chain, the centering drive active sprocket is linked with a centering hydraulic motor, and the body of the centering hydraulic motor is installed on the centering frame.

5. The hollow last forming process of a molded shoe according to claim 4, characterized in that: The flip positioning device includes a clamping body and a support frame. The support frame is detachably mounted on the movable guide plate of the shoe last by screws. One end of the clamping body is linked to a rotating shaft. Both ends of the rotating shaft are hinged to the support frame by bearings. The end of the rotating shaft is linked to a second driven sprocket. The second driven sprocket is linked to a second driving sprocket through a chain. The second driving sprocket is linked to a flip hydraulic motor. The flip hydraulic motor is mounted on the support frame.

6. The hollow last forming process for molded shoes according to claim 5, characterized in that: The left longitudinal center positioning groove and the right longitudinal center positioning groove are parallel to each other and are on the same straight line trajectory; the upper end surface of the shoe last fixed guide plate is the left positioning reference plane, and the upper end surface of the shoe last movable guide plate is the right positioning reference plane. The left positioning reference plane and the right positioning reference plane are parallel to each other and are on the same horizontal plane.

7. The hollow last forming process for molded shoes according to claim 6, characterized in that: The linear motion mechanism includes a lifting block fixed to the bottom of the shoe last movable guide plate by screws, the lifting block is linked to a third slider, the third slider is slidably matched with a second slide rail, the second slide rail is fixed on the frame and the second slide rail is arranged parallel to the right longitudinal center positioning groove, a transmission block is fixed under the shoe last movable guide plate, the transmission block is linked to a cylinder, the body of the cylinder is fixed on the frame, and the cylinder can drive the shoe last movable guide plate to reciprocate axially along the second slide rail through the transmission block.

8. The process for forming a hollow shoe last according to claim 1 or 2, characterized in that: The shoe last finished product processing tooling includes two groups of rotating seats fixedly installed on the frame and cutting positioning plates distributed between the two groups of rotating seats. Both ends of the cutting positioning plates are linked with rotating blocks, and the rotating blocks can be rotatably installed on the rotating seats. One group of rotating blocks is linked with a shoe last positioning hydraulic motor, and the outer periphery of the rotating blocks is evenly distributed with scale marks. The rotating seat is provided with a directional arrow for pointing to the scale marks.

Images