A mold capable of multi-mode production and molding

Abstract

The present invention discloses a mold capable of multi-mode production and molding, which belongs to the technical field of mold product production, and includes an upper mold, a lower mold, a molding and blanking component, a product lifting component, a demoulding and taking-out component, and a molding and cooling component. The upper mold and the lower mold are arranged in correspondence with each other, the molding and blanking component is located on the upper mold, the product lifting component is arranged on the lower mold, and the product lifting component and the lower mold are slidably matched, the demoulding and taking-out component is arranged on the product lifting component, the demoulding and taking-out component is rotationally connected with the product lifting component, and the molding and cooling component is arranged in the lower mold and the molding and cooling component surrounds the lower mold. The present invention lifts the product upward by cooperating with the product lifting component through the demoulding and taking-out component, so that the product can be lifted upward evenly when it is lifted upward without adhesion and affecting the integrity of the product, so as to quickly demould the product without affecting the quality and quality of subsequent products.

Description

Technical Field

[0001] The invention belongs to the technical field of mold product production, and in particular relates to a mold capable of multi-mode production and molding. Background Art

[0002] In today's manufacturing industry, efficient, flexible and cost-effective production models have become key factors in corporate competition. As the core tool for molding processing, molds play a vital role in many fields such as plastic products, metal die-casting, and rubber products. Although the traditional single-mold production method is mature, it often exposes problems such as low production efficiency, frequent mold changes, and high costs when facing diversified and small-batch market demands. With the development of intelligent manufacturing, the demand for intelligent and multifunctional mold systems is growing.

[0003] Molds are various molds and tools used in industrial production to obtain the desired products by injection molding, blow molding, extrusion, die casting or forging, smelting, stamping and other methods. Traditional single-function mold design is only suitable for a single product form. Once the product design changes, the mold needs to be redesigned and manufactured, resulting in a long production cycle and high costs.

[0004] However, the prior art still has the following problems: when demolding the finished product, the mold and the product fit tightly, which causes the product to get stuck on the mold and is difficult to demold; forcibly demolding the product during the demolding process will cause damage to the product and affect the subsequent use of the mold; and the existing mold can only mold one product at a time during the molding process, which affects the efficiency of product molding. Summary of the invention

[0005] The embodiment of the present invention provides a mold capable of multi-mode production and molding to solve the problems in the prior art.

[0006] The embodiment of the present invention adopts the following technical scheme: a mold capable of multi-mode production and molding, comprising an upper mold, a lower mold, a molding and unloading assembly, a product lifting assembly, a demoulding and removing assembly, and a molding and cooling assembly, wherein the upper mold and the lower mold are arranged in correspondence with each other, the molding and unloading assembly is located on the upper mold and a horizontally arranged discharge trough is provided on the upper mold, the product lifting assembly is arranged on the lower mold and the product lifting assembly and the lower mold are slidably matched, the demoulding and removing assembly is arranged on the product lifting assembly, the demoulding and removing assembly is rotatably connected with the product lifting assembly, the molding and cooling assembly is arranged in the lower mold and the molding and cooling assembly surrounds the lower mold, the lower mold is provided with a mold molding cavity, the mold molding cavity is provided with a plurality of horizontally arranged molding cavities, and the product lifting assembly can drive the mold molding cavity to move upward. The present invention lifts the product upward by cooperating with the product lifting assembly through the demoulding and removing assembly, so that the product can be lifted upward evenly when it is lifted upward without adhesion affecting the integrity of the product, so as to quickly demould the product without affecting the quality and quality of subsequent products.

[0007] Furthermore, the molding and unloading assembly includes a power transmission structure, a moving rod, a moving screw, a moving block and a unloading funnel, the moving rod is horizontally arranged in the upper mold, the two ends of the moving screw are rotatably connected in the upper mold, and the moving rod and the moving screw are symmetrically arranged on both sides of the top of the discharge trough, the moving block is slidably matched with the moving rod, and the moving block is threadedly connected with the moving screw, the power transmission structure is located in the upper mold, and the power transmission structure is transmission-connected with the moving screw, the unloading funnel is vertically arranged on the moving block, and the unloading funnel is located at the top of the discharge trough. The raw materials can be evenly transported to multiple horizontally arranged molding cavities on the lower mold, and multiple products can be molded at one time, and the raw materials will not be piled up in one place to affect the molding of the products.

[0008] Furthermore, a horizontally arranged movable cylinder is provided in the upper mold, and a movable cover plate cooperating with the movement of the upper mold is provided on the telescopic end of the movable cylinder.

[0009] Furthermore, the product lifting assembly includes a base, a lifting block, a lifting seat, a lifting movable plate, a lifting electric cylinder and two moving wheels. The base is horizontally arranged in the molding cavity of the lower mold, the lifting block is horizontally arranged on the base and the lifting block and the base are slidably matched, the two moving wheels are symmetrically connected to the lifting block, the lifting movable plate is vertically arranged at the bottom of the lifting seat, the lifting movable plate is provided with an inclined groove for the movement of the two moving wheels, the lifting electric cylinder is horizontally arranged inside the lower mold and the lifting electric cylinder is connected to the lifting block, the lower mold is provided with a lifting groove that is slidably matched with the lifting seat, and the lifting movable plate and the base are slidably matched up and down. The finished product in the lower mold can be lifted and lifted upward, and the product can be moved out of the lower mold, which is convenient for workers to take the product.

[0010] Furthermore, a mounting cavity is provided in the lifting seat, and grid holes are provided on the four side walls of the lifting seat.

[0011] Furthermore, the demoulding and removing assembly includes a rotating motor, a rotating wheel and a plurality of air outlet nozzles. The rotating wheel is horizontally rotatably connected in the installation cavity, and the plurality of air outlet nozzles are equidistantly arranged on the rotating wheel. The rotating motor is located on the lifting movable plate and the main shaft of the rotating motor is transmission-connected to the rotating wheel.

[0012] When in use, the rotating motor drives the rotating wheel to rotate in the installation cavity, so that the multiple air outlet nozzles can transport the gas outward more evenly.

[0013] Furthermore, the molding cooling assembly includes a cooling pipe and a water inlet pipe. The cooling pipe is arranged in a curved shape in the lower mold, and the water inlet pipe is connected to the cooling pipe.

[0014] It can make the product and the lower mold separate quickly, and is also conducive to the subsequent demoulding operation of the product.

[0015] Furthermore, four positioning rods are provided at the bottom of the upper mold, and four shock-absorbing dampers are provided on the lower mold, and the four shock-absorbing dampers are arranged corresponding to the four positioning rods.

[0016] At least one of the above technical solutions adopted in the embodiments of the present invention can achieve the following beneficial effects:

[0017] Firstly, when the product needs to be demolded after being formed, the lifting electric cylinder of the present invention drives the lifting block to move horizontally on the base, thereby driving the two moving wheels to move in the two inclined grooves in the lifting moving plate. The movement causes the position of the lifting moving plate to move upward, thereby causing the position of the lifting block to move upward in the lifting groove, thereby lifting and lifting the product formed in the lower mold upward, and moving the product out of the lower mold, making it convenient for workers to take the product.

[0018] Secondly, when the present invention is lifted upward by the lifting seat, several air outlet nozzles all discharge gas outward, and the gas is transported outward to between the product and the lower mold through the grid holes. When the lifting block is lifted upward for demoulding, the gas can lift the product upward evenly and separate the product from the lower mold, support the bottom of the product, so that there is no adhesion when the product is separated upward, and the product is lifted upward evenly, so that the demoulding effect of the product is better; after the product is demoulded and separated, several air outlet nozzles work to spray gas to clean the lower mold. When in use, the rotating motor works to drive the rotating wheel to rotate in the installation cavity, which can make the several air outlet nozzles more uniform when transporting gas outward.

[0019] Thirdly, the water inlet pipe of the present invention is connected to the external circulation pump. After the product is formed, the cooling water is transported to the cooling pipe through the water inlet pipe by the circulation pump. The formed mold is quickly cooled and formed through the cooling pipe, which can quickly separate the product from the lower mold and is also beneficial to the subsequent demolding operation of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0021] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0022] Figure 2 It is a three-dimensional structural schematic diagram of the forming and blanking component in the present invention;

[0023] Figure 3 It is a schematic diagram of a first partial three-dimensional structure of the present invention;

[0024] Figure 4 It is a schematic diagram of a second partial three-dimensional structure of the present invention;

[0025] Figure 5 It is a schematic diagram of the first three-dimensional structure of the product lifting assembly in the present invention;

[0026] Figure 6 It is a second three-dimensional structural schematic diagram of the product lifting assembly in the present invention;

[0027] Figure 7 It is a schematic diagram of the three-dimensional structure of the demoulding and removing component in the present invention;

[0028] Figure 8 It is a schematic diagram of the three-dimensional structure of the upper mold in the present invention;

[0029] Fig. 9It is a schematic diagram of the three-dimensional structure of the lower mold in the present invention;

[0030] Reference numerals

[0031] Upper mold 1; discharge chute 11; positioning rod 12; lower mold 2; shock absorbing damper 21; lifting groove 22; molding unloading component 3; power transmission structure 31; moving rod 32; moving screw rod 33; moving block 34; unloading funnel 35; moving cylinder 4; moving cover plate 41; product lifting component 5; base 51; lifting block 52; lifting seat 53; lifting moving plate 54; lifting electric cylinder 55; moving wheel 56; grid hole 57; inclined groove 58; demoulding and removing component 6; rotating motor 61; rotating wheel 62; air outlet nozzle 63; molding cooling component 7; cooling pipe 71. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. 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 making creative work are within the scope of protection of the present invention.

[0033] The technical solutions provided by various embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0034] Reference Figures 1 to 9 As shown, the embodiment of the present invention provides a mold capable of multi-mode production and molding, including an upper mold 1, a lower mold 2, a molding and unloading assembly 3, a product lifting assembly 5, a demoulding and removing assembly 6, and a molding and cooling assembly 7. The upper mold 1 and the lower mold 2 are arranged in correspondence with each other from top to bottom. The molding and unloading assembly 3 is located on the upper mold 1 and the upper mold 1 is provided with a horizontally arranged discharge trough 11. The product lifting assembly 5 is arranged on the lower mold 2 and the product lifting assembly 5 is slidably matched with the lower mold 2. The demoulding and removing assembly 6 is arranged on the product lifting assembly 5, and the demoulding and removing assembly 6 is rotatably connected with the product lifting assembly 5. The molding and cooling assembly 7 is arranged in the lower mold 2 and surrounds the lower mold 2. A mold molding cavity is provided in the lower mold 2, and a plurality of horizontally arranged molding cavities are provided on the mold molding cavity. The product lifting assembly 5 can drive the mold molding cavity to move upward; the plurality of horizontally arranged molding cavities can realize simultaneous molding operations for multiple products, thereby improving work efficiency.

[0035] The upper mold 1 is connected to a downward conveying power assembly in the prior art, which can drive the upper mold 1 to move downward and move closer to the lower mold 2 for mold closing.

[0036] In this embodiment, when the product is being molded, the upper mold 1 moves downward and approaches the lower mold 2, and the raw material is evenly transported between the upper mold 1 and the lower mold 2 through the molding and unloading component 3, and the position of the molding and unloading component 3 during the unloading process can be moved left and right, so when the products in multiple horizontally arranged molding cavities are carried, the molding and unloading work can be carried out in sequence, and when the product is being molded, the molding cooling component 7 is used to evenly cool the completed molded product, and after cooling and molding, the product lifting component 5 is used to lift the product upward from the lower mold 2, and the demolding and removal component 6 cooperates with the product lifting component 5 to lift the product upward, so that the product can be evenly lifted upward when it is lifted upward without adhesion affecting the integrity of the product, so that the product can be quickly demolded without affecting the quality and quality of subsequent products, and the demolding and removal component 6 can also be used to clean the lower mold 2.

[0037] Specifically, the molding and unloading assembly 3 includes a power transmission structure 31, a moving rod 32, a moving screw 33, a moving block 34 and a unloading funnel 35, wherein the moving rod 32 is horizontally arranged in the upper mold 1, the two ends of the moving screw 33 are rotatably connected in the upper mold 1, and the moving rod 32 and the moving screw 33 are symmetrically arranged on both sides of the top of the discharge trough 11, the moving block 34 is slidably matched with the moving rod 32, and the moving block 34 is threadedly connected with the moving screw 33, the power transmission structure 31 is located in the upper mold 1, and the power transmission structure 31 is transmission-connected with the moving screw 33, and the unloading funnel 35 is vertically arranged on the moving block 34, and the unloading funnel 35 is located at the top of the discharge trough 11. The power transmission structure 31 can be a motor, a rotating disk or other power structure that drives the moving rod 33 to rotate, and can drive the moving screw 33 to rotate.

[0038] In this embodiment, external raw materials pass through the discharge funnel 35 between the closed upper mold 1 and the lower mold 2. At this time, the power transmission structure 31 works to drive the movable screw 33 to rotate in the upper mold 1, so that the position of the movable block 34 moves horizontally along the position of the movable rod 32. When the raw materials are discharged, the raw materials can be evenly transported to multiple horizontally arranged molding cavities on the lower mold 2, and multiple products can be molded at one time without causing the raw materials to accumulate in one place and affecting the molding of the products.

[0039] Specifically, a horizontally arranged mobile cylinder 4 is provided in the upper mold 1, and a mobile cover plate 41 is provided on the telescopic end of the mobile cylinder 4 to cooperate with the movement of the upper mold 1; when the product is formed, the mobile cylinder 4 drives the position of the mobile cover plate 41 to move, and the discharge trough 11 can be covered by the mobile cover plate 41 to ensure sealing during molding.

[0040] Specifically, the product lifting assembly 5 includes a base 51, a lifting block 52, a lifting seat 53, a lifting movable plate 54, a lifting electric cylinder 55 and two moving wheels 56. The base 51 is horizontally arranged in the mold molding cavity of the lower mold 2, the lifting block 52 is horizontally arranged on the base 51 and the lifting block 52 is slidably matched with the base 51, the two moving wheels 56 are symmetrically connected to the lifting block 52, the lifting movable plate 54 is vertically arranged at the bottom of the lifting seat 53, and the lifting movable plate 54 is provided with an inclined groove 58 for the two moving wheels 56 to move, the lifting electric cylinder 55 is horizontally arranged inside the lower mold 2 and the lifting electric cylinder 55 is connected to the lifting block 52, the lower mold 2 is provided with a lifting groove 22 that is slidably matched with the lifting seat 53, and the lifting movable plate 54 is slidably matched with the base 51 up and down.

[0041] In this embodiment, when the product needs to be demolded after being formed, the lifting electric cylinder 55 works to drive the lifting block 52 to move horizontally on the base 51, thereby driving the two moving wheels 56 to move in the two inclined grooves 58 in the lifting moving plate 54. The movement causes the position of the lifting moving plate 54 to move upward, thereby causing the position of the lifting block 52 to move upward in the lifting groove 22, thereby lifting and lifting the product that has been formed in the lower mold 2, and moving the product out of the lower mold 2, which makes it convenient for workers to take the product without causing the product to be stuck in the lower mold 2, causing trouble in taking out the product, and also improves work efficiency.

[0042] Specifically, an installation cavity is provided in the lifting seat 53, and grid holes 57 are provided on the four side walls of the lifting seat 53; the demolding and removal component 6 includes a rotating motor 61, a rotating wheel 62 and a plurality of air outlet nozzles 63, the rotating wheel 62 is horizontally rotatably connected in the installation cavity, and a plurality of the air outlet nozzles 63 are equidistantly arranged on the rotating wheel 62, the rotating motor 61 is located on the lifting movable plate 54, and the main shaft of the rotating motor 61 is transmission-connected to the rotating wheel 62.

[0043] In this embodiment, when the lifting seat 53 is used to lift the product upward, a plurality of air outlet nozzles 63 discharge gas outward, and the gas is transported outward to between the product and the lower mold 2 through the grid holes 57. When the lifting block 52 is lifted upward for demolding, the gas can lift the product upward evenly and separate the product from the lower mold 2, and support the bottom of the product, so that there is no adhesion when the product is separated upward, and the product is lifted upward evenly, so that the demolding effect of the product is better; after the product is demolded and separated, a plurality of air outlet nozzles 63 work to spray gas to clean the lower mold 2. When in use, the rotating motor 61 works to drive the rotating wheel 62 to rotate in the installation cavity, so that the plurality of air outlet nozzles 63 can transport the gas outward more evenly.

[0044] Specifically, the molding cooling assembly 7 includes a cooling pipe 71 and a water inlet pipe. The cooling pipe 71 is arranged in a curved shape in the lower mold 2 , and the water inlet pipe is connected to the cooling pipe 71 .

[0045] In this embodiment, the water inlet pipe is connected to an external circulation pump. After the product is formed, the cooling water is transported to the cooling pipe 71 through the water inlet pipe by the circulation pump. The formed mold is quickly cooled by the cooling pipe 71, which can quickly separate the product from the lower mold 2 and is also beneficial to the subsequent demolding operation of the product.

[0046] Specifically, four positioning rods 12 are provided at the bottom of the upper mold 1, and four shock absorbing dampers 21 are provided on the lower mold 2. The four shock absorbing dampers 21 are arranged corresponding to the four positioning rods 12;

[0047] In this embodiment, when the upper mold 1 moves downward, the four positioning rods 12 move downward into the four shock-absorbing dampers 21 of the lower mold 2, which can absorb the impact force and reduce the vibration, thereby avoiding the influence of the vibration on the cooperation between the upper mold 1 and the lower mold 2 on the molded product.

[0048] Working principle: When using the product,

[0049] In the first step, the upper mold 1 moves downward to approach the lower mold 2, and the external raw materials pass through the feeding funnel 35 between the closed upper mold 1 and the lower mold 2. At this time, the power transmission structure 31 drives the moving screw 33 to rotate in the upper mold 1, so that the position of the moving block 34 moves horizontally along the position of the moving rod 32, so that when the raw materials are discharged, the raw materials can be evenly transported to multiple molding cavities on the lower mold 2;

[0050] In the second step, the water inlet pipe is connected to the external circulation pump. After the product is formed, the cooling water is transported to the cooling pipe 71 through the water inlet pipe by the circulation pump. The formed mold is quickly cooled and formed through the cooling pipe 71, which can quickly separate the product from the lower mold 2 and facilitate the subsequent demoulding operation of the product.

[0051] In the third step, when the product needs to be demoulded, the lifting electric cylinder 55 drives the lifting block 52 to move horizontally on the base 51, thereby driving the two moving wheels 56 to move in the two inclined grooves 58 in the lifting moving plate 54, so that the position of the lifting moving plate 54 moves upward, thereby causing the position of the lifting block 52 to move upward in the lifting groove 22, and the product formed in the lower mold 2 is lifted and lifted upward, and the product is moved out of the lower mold 2, so that the workers can take the product conveniently;

[0052] In the fourth step, when the lifting seat 53 is lifted upward, the plurality of gas outlet nozzles 63 discharge gas outward, and the gas is transported outward to the space between the product and the lower mold 2 through the grid holes 57. When the lifting block 52 is lifted upward for demoulding, the gas can lift the product upward uniformly and separate the product from the lower mold 2, support the bottom of the product, so that the product does not stick to the lower mold 2 when it is separated upward, and lift the product upward uniformly, so that the demoulding effect of the product is better;

[0053] After the product is demoulded and separated, the plurality of air outlet nozzles 63 work to spray gas to clean the lower mold 2. When in use, the rotating motor 61 works to drive the rotating wheel 62 to rotate in the installation cavity, so that the plurality of air outlet nozzles 63 can transport the gas outward more evenly.

[0054] The fifth step is to lift the product upward and then take it out manually.

[0055] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A mold capable of multi-mode production, characterized in that: It comprises an upper mold (1), a lower mold (2), a molding and unloading component (3), a product lifting component (5), a demoulding and removing component (6) and a molding and cooling component (7); The upper mold (1) and the lower mold (2) are arranged in correspondence with each other in the upper and lower parts, the molding and unloading assembly (3) is located on the upper mold (1), and the upper mold (1) is provided with a horizontally arranged discharge chute (11); The product lifting component (5) is arranged on the lower mold (2) and the product lifting component (5) and the lower mold (2) are slidably matched; The demoulding and removing component (6) is arranged on the product lifting component (5), and the demoulding and removing component (6) is rotatably connected to the product lifting component (5); The molding cooling component (7) is arranged in the lower mold (2) and the molding cooling component (7) surrounds the lower mold (2); The lower mold (2) is provided with a mold forming cavity, and the mold forming cavity is provided with a plurality of horizontally arranged forming cavities, and the product lifting component (5) can drive the mold forming cavity to move upwards.

2. A multi-mode production mold according to claim 1, characterized in that: The molding and unloading assembly (3) comprises a power transmission structure (31), a moving rod (32), a moving screw rod (33), a moving block (34) and a unloading funnel (35); The moving rod (32) is horizontally arranged in the upper mold (1), the two ends of the moving screw rod (33) are rotatably connected in the upper mold (1), and the moving rod (32) and the moving screw rod (33) are symmetrically arranged on both sides of the top of the discharge trough (11); The moving block (34) and the moving rod (32) are slidably matched and the moving block (34) and the moving screw rod (33) are threadedly connected, the power transmission structure (31) is located in the upper mold (1) and the power transmission structure (31) and the moving screw rod (33) are transmission-connected; The material discharge funnel (35) is vertically arranged on the moving block (34) and the material discharge funnel (35) is located at the top of the material discharge trough (11).

3. A multi-mode production mold according to claim 2, characterized in that: A horizontally arranged movable cylinder (4) is provided in the upper mold (1), and a movable cover plate (41) which is movable in coordination with the upper mold (1) is provided on the telescopic end of the movable cylinder (4).

4. The multi-mode production mold according to claim 1, characterized in that: The product lifting assembly (5) comprises a base (51), a lifting block (52), a lifting seat (53), a lifting movable plate (54), a lifting electric cylinder (55) and two movable wheels (56); The base (51) is horizontally arranged in the mold forming cavity of the lower mold (2), and the lifting block (52) is horizontally arranged on the base (51), and the lifting block (52) and the base (51) are slidably matched; The two moving wheels (56) are symmetrically connected to the lifting block (52), and the lifting moving plate (54) is vertically arranged at the bottom of the lifting seat (53). The lifting movable plate (54) is provided with an inclined groove (58) for the two movable wheels (56) to move, and the lifting electric cylinder (55) is horizontally arranged inside the lower mold (2) and the lifting electric cylinder (55) is connected to the lifting block (52); The lower mold (2) is provided with a lifting groove (22) that is slidably matched with the lifting seat (53), and the lifting movable plate (54) is slidably matched with the base (51) up and down.

5. A multi-mode production mold according to claim 4, characterized in that: The lifting seat (53) is provided with a mounting cavity, and the four side walls of the lifting seat (53) are provided with grid holes (57).

6. A multi-mode production mold according to claim 5, characterized in that: The demoulding and removing component (6) comprises a rotating motor (61), a rotating wheel (62) and a plurality of air outlet nozzles (63); The rotating wheel (62) is horizontally rotatably connected in the installation cavity, and a plurality of the air outlet nozzles (63) are arranged on the rotating wheel (62) at equal intervals; The rotating motor (61) is located on the lifting moving plate (54), and the main shaft of the rotating motor (61) is drivingly connected to the rotating wheel (62).

7. The multi-mode production mold according to claim 1, characterized in that: The molding cooling assembly (7) comprises a cooling pipe (71) and a water inlet pipe. The cooling pipe (71) is arranged in a bent shape in the lower mold (2), and the water inlet pipe is connected to the cooling pipe (71).

8. The multi-mode production mold according to claim 1, characterized in that: The bottom of the upper mold (1) is provided with four positioning rods (12), and the lower mold (2) is provided with four shock absorbing dampers (21), and the four shock absorbing dampers (21) are arranged corresponding to the four positioning rods (12).

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