CN116851708A - Low-pressure casting device and low-pressure casting die bottom die synchronous jacking device - Google Patents

Abstract

The invention discloses a low-pressure casting device and a bottom die synchronous ejection device of a low-pressure casting die. The device comprises the top plate assembly, a plurality of sliding blocks, a plurality of sliding block fixing blocks, a plurality of springs, a plurality of top die inclined rods, a plurality of bottom die inclined rods, a plurality of ejector rods and a plurality of reset rods, wherein the contact surfaces of the sliding blocks, the top die inclined blocks and the bottom die inclined blocks are inclined planes for providing driving for the top die and reset, the bottom of the top die inclined rods is in a hook shape, and the sliding blocks can be hooked to move upwards to realize the top die. The material ejection device in the low-pressure casting device adopts a pure mechanical structure design, the manufacturing cost is far lower than that of a side-drawing assembly with an oil cylinder, a hydraulic system of a low-pressure machine is not required to be connected, manual independent operation is not required, the complete automatic synchronization of the opening time and displacement distance of the bottom die ejector plate and the top die can be ensured, the problem that the top die is difficult to remain in castings with large bottom die holding force and the problem that thin plate castings are easy to deform in die opening are solved, and the operation is safe, reliable and efficient.

Description

Low-pressure casting device and low-pressure casting die bottom die synchronous jacking device

Technical Field

The invention relates to an auxiliary device for casting, in particular to a bottom die synchronous jacking device of a low-pressure casting die.

Background

The low pressure casting process is that a crucible furnace is placed under a mould, a liquid lifting pipe is used in the middle to connect a furnace chamber with a mould cavity, compressed air of 100-500 mbar is introduced into the furnace chamber, molten metal in the furnace chamber flows into the mould cavity through the liquid lifting pipe in a rising way, after the molten metal in the mould cavity is cooled and solidified, the pressure of the furnace chamber is relieved, the rest of molten metal flows back into the furnace chamber, and the mould is opened to take out castings to finish the casting process once.

Because of the special equipment and process, the design principle of low-pressure casting is that a bottom die (also called a lower die) is not provided with an ejection device, a casting is left on a top die (also called an upper die) under the action of holding force after die opening, the casting is ejected onto a receiving tray through a material ejection cylinder of the top die, and if the casting is carelessly left on the bottom die, the casting cannot be normally taken out, and the production can only be forcedly interrupted.

For example, after the casting position of some castings, especially castings of thin plate end covers, is determined according to the principle of optimal casting, mold filling and solidification, the holding force of the bottom mold may be far greater than that of the top mold, which can lead to that the castings are not left on the top mold during mold opening, and continuous production cannot be performed.

The solutions of the prior art have two kinds: the first is to add a jacking cylinder on the bottom die, but as shown in the above figure, there is usually not enough installation space between the bottom die and the furnace, even if the jacking cylinder can be installed, the jacking cylinder and the equipment die-opening cylinder cannot be hydraulically synchronized (the non-synchronization can lead to the deformation of the top of the casting), in addition, the temperature of the area close to the furnace is very high, the rubber sealing ring of the cylinder can be damaged frequently, and the method is almost unmanned in practical production.

The second method is to add some side core-pulling cores at the part of the casting formed by the top die to clamp the casting, and open the core-pulling cores after the casting is completely separated from the bottom die, so that the casting can be ejected.

Disclosure of Invention

In order to overcome the defects or shortcomings in the prior art, according to one aspect of the present invention, there is provided a low pressure casting device, including a top mold and a bottom mold, wherein a mold cavity is formed inside the assembled top mold and bottom mold, and the top mold is located above the bottom mold, the device further includes:

a top plate assembly;

a plurality of sliders; the sliding block comprises a sliding block body, wherein a second inclined plane A is arranged on one end face of the sliding block body, a through hole is further formed in the sliding block body, the axial direction of the through hole is parallel to the end face, a first inclined plane A is arranged on the inner side wall of the through hole, and the end face where the second inclined plane A is located is parallel to the inner side face where the first inclined plane A is located;

a plurality of slider fixing blocks; the sliding block fixing block comprises a fixing block body, a cavity is formed in the fixing block body, a first hole and a second hole are formed in the fixing block body at the same time, the first hole is communicated with the cavity, the second hole penetrates through the cavity and penetrates through the bottom of the cavity, and the first hole is parallel to the second hole in the axial direction;

a plurality of springs;

a plurality of top mold diagonal bars; the top die inclined rod comprises a rod body, wherein the bottom end of the rod body is provided with a hook structure, and one side of the bottom surface of the hook is provided with a first inclined plane B;

a plurality of bottom mold diagonal bars; the bottom die diagonal bar comprises a body bar, and a second inclined plane B is arranged at the bottom of the body bar;

a plurality of ejector rods and a plurality of reset rods;

the top plate assembly is arranged below the bottom die, one end of each ejector rod is fixed on the top plate assembly, the other end of each ejector rod penetrates through the bottom die and stretches into the bottom of the die cavity, and the plurality of ejector rods are uniformly distributed at the bottom of the die cavity;

one end of each reset rod is fixed on the top plate assembly, and the other end of each reset rod passes through the bottom die and contacts with the parting surface of the top die;

the sliding block fixing blocks are fixed on the top plate assembly and distributed on the front side and the rear side of the top plate assembly; the sliding block is arranged in the cavity of each sliding block fixing block, the sliding block can move left and right in the cavity, meanwhile, a spring is arranged between one end of the sliding block and the inner wall of the cavity, and the compression direction of the spring is along the movement direction of the sliding block; the first holes and the second holes are distributed along the moving direction of the sliding block, and the springs are positioned at the end parts close to the second holes;

the top of each die diagonal bar is fixed on the die block, and the distribution mode of many die diagonal bars satisfies: the bottom end of each bottom die diagonal rod extends into the cavity through a first hole at the lower position of the bottom die diagonal rod and is positioned at the same end with a second inclined plane A of the sliding block, and meanwhile, the second inclined plane B is matched with the second inclined plane A;

the top of each top mould diagonal bar is fixed on the top mould, and the distribution mode of many top mould diagonal bars satisfies: the bottom end of each top die inclined rod stretches into the cavity through a second hole at the lower position of the bottom die inclined rod and penetrates through the through hole of the sliding block, the hook surface is partially attached to the bottom surface of the sliding block, and in the process that the top surface inclined rod penetrates through the through hole downwards, the first inclined surface B is matched with the first inclined surface A; the part of the hook surface, which is jointed with the bottom surface of the sliding block, is jointed with an inclined surface.

In a further scheme, the inclination angles of the second inclined plane A, the first inclined plane A and the inclined plane of the joint part of the hook surface and the bottom surface of the sliding block are different.

Alternatively, two slide block fixing blocks are respectively arranged on the front side and the rear side of the top plate assembly.

Alternatively, the extension dimension of the hooks is the minimum distance that the castings need to be separated from the bottom die. Further alternatively, the minimum distance that the casting needs to be separated from the bottom die is 20-40mm.

The alternative scheme is that the die comprises four reset rods, wherein the four reset rods are distributed at four vertex angle positions of the parting surface of the top die.

The optional scheme is that the roof subassembly is assembled by two plates, be equipped with the central through-hole that holds the lift cover on the roof subassembly, a plurality of ejector pins distribute with around the central through-hole.

In a further aspect, the low pressure casting apparatus of the present invention further comprises a crucible furnace, the crucible furnace being located below the lower mold, and the top plate assembly being located between the crucible furnace and the lower mold. The die further comprises a low-pressure machine and a die opening oil cylinder, wherein the bottom die and the top surface are connected with the low-pressure machine, and the top die is connected with the die opening oil cylinder.

The invention also provides a bottom die synchronous ejection device of the low-pressure casting die, which comprises the top plate assembly, a plurality of sliding blocks, a plurality of sliding block fixing blocks, a plurality of springs, a plurality of top die diagonal rods, a plurality of bottom die diagonal rods, a plurality of ejector rods and a plurality of reset rods.

The material ejection device in the low-pressure casting device adopts a pure mechanical structure design, the manufacturing cost is far lower than that of a side-drawing assembly with an oil cylinder, a hydraulic system of a low-pressure machine is not required to be connected, manual independent operation is not required, the complete automatic synchronization of the movement of the bottom die material ejection plate and the opening time and displacement distance of the top die can be ensured, the problem that the casting with high holding force of the bottom die is difficult to leave the top die and the problem that the sheet casting is easy to deform can be solved at one time, and the operation is safe, reliable and efficient.

Drawings

FIG. 1 is a top plan view of a top plate assembly and mounting components thereon of the present invention;

FIG. 2 is a side view of the top plate assembly and mounting components thereon of the present invention;

FIG. 3 is a partial block diagram of the low pressure casting apparatus of the present invention;

FIG. 4 is an enlarged view of the structure within the slider mount of FIG. 3;

FIG. 5 is a schematic view of the structure of the slider of the present invention.

Detailed Description

Unless specifically stated otherwise, scientific and technical terms herein have been understood based on the knowledge of one of ordinary skill in the relevant art.

The terms of front, back, left, right, bottom, top, upper, lower, etc. as used herein, are used in reference to corresponding directions or orientations in the drawings. It is noted that the specific direction or orientation in the drawings in the specification is intended to explain the present invention, and that equivalent changes of orientation, rotation, exchange, etc. made by those skilled in the art based on the disclosure herein are within the scope of the present invention.

The minimum distance the castings described herein will be removed from the bottom mold is typically the minimum distance from the bottom of the casting to the top of the mold core, typically 20-40mm.

Examples:

referring to fig. 1 to 5, the ejection device of this embodiment includes a top plate assembly 8, a plurality of sliders 6, a plurality of slider fixing blocks 5, a plurality of springs 7, a plurality of top mold diagonal rods 3, a plurality of bottom mold diagonal rods 4, a plurality of ejector rods 9, and a plurality of reset rods 10; wherein, the liquid crystal display device comprises a liquid crystal display device,

a second inclined plane A62 is arranged on one end face of the sliding block body, a through hole 61 is further formed in the sliding block body, the axial direction of the through hole is parallel to the end face, a first inclined plane A63 is arranged on one inner side wall of the through hole, and the end face of the second inclined plane A is parallel to the inner side face of the first inclined plane A;

the sliding block fixing block comprises a body, a first hole and a second hole, wherein the body of the sliding block fixing block is internally provided with a cavity, the first hole is communicated with the cavity, the second hole penetrates through the cavity and penetrates through the bottom of the cavity, and the first hole is parallel to the second hole in the axial direction;

the bottom end of the top die inclined rod body is provided with a hook structure, and one side of the bottom surface of the hook is provided with a first inclined plane B; the bottom of the bottom die diagonal bar body is provided with a second inclined plane B;

the ejection device is matched with the existing low-pressure machine and ejection oil cylinder of the ejection die to finish die opening and casting separation, and the specific installation mode is that the ejection device is characterized in that the ejection die 1 and the bottom die 2 are installed on the low-pressure machine after being closed together, the bottom die 2 and a bottom plate of the low-pressure machine are fixed together, the ejection die 1, an ejection die mounting plate of the low-pressure machine and the ejection oil cylinder of the ejection die can be moved up and down during die opening, a cavity in the middle of the bottom die and the ejection die after assembly is a die cavity 11, and the cavity is a casting forming position.

The crucible furnace is communicated with the mold cavity through a liquid lifting pipe, and the liquid lifting sleeve is tightly attached to the liquid lifting pipe opening of the crucible furnace; the top plate assembly 8 is arranged between the crucible furnace and the bottom die, and the top plate assembly 8 is positioned around the liquid lifting sleeve of the bottom die or the liquid lifting sleeve of the bottom die passes through the top plate assembly 8;

according to the technical scheme of the invention, one end of each top die inclined rod 3 is fixed with the top die 1 and can move up and down along with the opening and closing of the top die; the bottom die diagonal rods 4 are fixed with the bottom die 2 at one section, and common fixing modes such as welding, bolting and the like can be adopted in the concrete scheme;

a plurality of ejector rods 9 are arranged on the top plate assembly 8, a reset rod 10 is further arranged at the position, close to the four corners, of the top plate, the upper end parts of the ejector rods 9 are in contact with the casting cavity, and the upper end parts of the reset rods 10 are in contact with the parting surface of the die.

The sliding block fixing block 5 of the embodiment is arranged on the side surfaces of four corners of the top plate assembly 8, the cavity of the sliding block 6 for installing the sliding block fixing block can move left and right, and one end of the sliding block 6 close to the outer side is provided with a reset spring 7;

the contact surfaces of the sliding block 6, the top die inclined rod 3 and the bottom die inclined rod 4 are inclined planes, the inclination angles of the contact inclined planes are different, and meanwhile, the bottom of the top die inclined rod 3 is in a hook shape and can hook the sliding block 6 and related components to move upwards; the inclination angle of each inclined surface is required to ensure that the device works smoothly and that the demolding and the mold assembly are realized smoothly, in the embodiment, the inclined surface a is 5 degrees, the inclined surface b is 75 degrees, and the inclined surface c is 60 degrees.

The working principle of the device is as follows:

(1) The top die 1 and the bottom die 2 are in a closed state, molten metal enters the die cavity 11 from a liquid lifting pipe of the crucible furnace, and castings are formed after the molten metal is filled, and the molten metal is gradually cooled and solidified;

(2) The die opening cylinder of the low-pressure machine drives the top die 1 and the top die inclined rod 3 to move upwards; simultaneously, under the sliding action of the bottom die inclined rod and the inclined plane B (second inclined planes A and B) at the end part of the sliding block at each position (such as four corners of the top plate assembly), the sliding action of the inclined plane a of the hook surface of the top die inclined rod 3, which is contacted with the bottom surface of the sliding block 6, and the driving action of the hook, the sliding block 6 synchronously moves rightward (away from the bottom die inclined rod) and upward in two directions, and because the sliding block 6 is arranged in the transverse cavity of the sliding block fixing block 5, the top plate assembly 8, the ejector rods 9 and the reset rod 10 are driven to move upward together, a plurality of uniformly distributed ejector rods 9 enable castings to be uniformly stressed and gradually separated from the bottom die 2 without deformation, and the reset spring 7 is in a gradually compressed state;

(3) After each slide block 6 moves rightwards for a certain distance (the distance is determined by the extending size of the hook and the minimum distance that the casting needs to be separated from the bottom die, the common minimum distance is 20-40 mm), the top die diagonal rod 3 is separated from the slide block 6, and at the moment, the slide block fixing block 5, the top plate assembly 8, the ejector rod 9 and the reset rod 10 stop moving upwards at the same time; the top die 1 carries the top die inclined rod 3 and the casting to move upwards, the top die inclined rod is separated from the slide block fixing block 5, and the return spring 7 starts to push the slide block 6 to return to the left until the two second inclined surfaces are contacted with the bottom die inclined rod 4 for lamination;

(4) After the ejector die diagonal rod 3 reaches a proper position, the low-pressure receiving tray rotates to extend below the ejector die, the ejector die ejector cylinder ejects the casting 11 out of the die and falls on the receiving tray, and the receiving tray withdraws;

(5) After the casting is taken out, the top die 1 moves downwards with each top die inclined rod 3, when the top die inclined rods move to inclined planes c (first inclined planes A and B) where the side parts of hooks at the bottom of the top die inclined rods 3 are contacted with corresponding sliding blocks 6, the sliding blocks 6 move rightwards to give up positions, and when hooks of the top die inclined rods 3 extend into the lower parts of the sliding blocks 6 completely, the sliding blocks 6 return leftwards under the action of the springs 7 to enable the hooks of the top die inclined rods 3 to hook the sliding blocks 6 again; at the same time, the parting surface of the top die 1 contacts with the end surface of the reset rod 10, and the reset rod 10 is pressed to drive the top plate assembly 8, the ejector rod 9 and the sliding block fixing block 5 to move downwards to return to the initial position in the step (1) until the die is completely closed.

Repeating the steps (1) - (5) to continuously produce castings; when one round of production is finished, after the device is cleaned and lubricated, the next round of production can be prepared, and all accessories (about 3 ten thousand to 5 ten thousand moulds) do not need to be replaced within the service life.

The hook surface is in inclined surface contact with the bottom surface of the sliding block (namely, the hook surface and the partial surface of the bottom surface of the sliding block are inclined surfaces), the contact inclined surface is an inclined pin sliding mechanism which can convert vertical input motion into horizontal output motion, so that the sliding block is driven to move towards a spring direction when the top die inclined rod moves upwards, and meanwhile, the sliding block fixing block, the top plate assembly and the top rod are driven to move upwards; the hooks at the bottom are separated from the sliding blocks.

The number of the sliding blocks, the sliding block fixing blocks, the top die and the reset rods is determined according to the size of low-pressure casting die equipment and the size of casting areas, and the larger equipment needs more sliding blocks and the fixing blocks thereof to realize the material ejection function so as to ensure the stability of work in the working process. In an actual scheme, a proper number can be selected and set according to the size of the equipment.

The structure and the shape of the top plate assembly can be designed according to the actual low-pressure casting die scene, so that each part of the material ejection device is convenient to install and the material ejection function is realized. An example is that the top plate assembly is assembled by two plates, a central through hole 81 for accommodating the liquid lifting sleeve and the liquid lifting pipe is formed in the top plate assembly, and the plurality of ejector rods are distributed around the central through hole.

In the concrete scheme, the top die diagonal rod 3, the bottom die diagonal rod 4, the slide block fixing block 5 and the slide block 6 are all made of alloy steel with treated surfaces, have higher hardness and wear resistance, and the rest are all made of common hot work die steel such as H13.

The above examples are preferred examples of the present invention, and equivalents and combinations thereof by those skilled in the art on the basis of the present disclosure are intended to be within the scope of the present invention.

Claims (10)

1. The utility model provides a low pressure casting device, includes top mould (1) and die block (2), inside mould die cavity (11) of formation after top mould and the die block equipment, and top mould is located the die block top, its characterized in that still includes:

a top plate assembly (8);

a plurality of sliders (6); the sliding block comprises a sliding block body, wherein a second inclined plane A (62) is arranged on one end face of the sliding block body, a through hole (61) is further formed in the sliding block body, the axial direction of the through hole is parallel to the end face, a first inclined plane A (63) is arranged on the inner side wall of the through hole, and the end face where the second inclined plane A is located is parallel to the inner side face where the first inclined plane A is located;

a plurality of slider fixing blocks (5); the sliding block fixing block comprises a fixing block body, a cavity is formed in the fixing block body, a first hole and a second hole are formed in the fixing block body at the same time, the first hole is communicated with the cavity, the second hole penetrates through the cavity and penetrates through the bottom of the cavity, and the first hole is parallel to the second hole in the axial direction;

a plurality of springs (7);

a plurality of top mold diagonal rods (3); the top die inclined rod comprises a rod body, wherein the bottom end of the rod body is provided with a hook structure, and one side of the bottom surface of the hook is provided with a first inclined plane B;

a plurality of bottom mold diagonal rods (4); the bottom die diagonal bar comprises a body bar, and a second inclined plane B is arranged at the bottom of the body bar;

a plurality of ejector rods (9) and a plurality of reset rods (10);

the top plate assembly (8) is arranged below the bottom die, one end of each ejector rod (9) is fixed on the top plate assembly, the other end of each ejector rod penetrates through the bottom die and stretches into the bottom of the die cavity, and the plurality of ejector rods are uniformly distributed at the bottom of the die cavity;

one end of each reset rod (10) is fixed on the top plate assembly, and the other end of each reset rod passes through the bottom die and contacts with the parting surface of the top die;

the sliding block fixing blocks are fixed on the top plate assembly and distributed on the front side and the rear side of the top plate assembly; the sliding block is arranged in the cavity of each sliding block fixing block, the sliding block can move left and right in the cavity, meanwhile, a spring is arranged between one end of the sliding block and the inner wall of the cavity, and the compression direction of the spring is along the movement direction of the sliding block; the first holes and the second holes are distributed along the moving direction of the sliding block, and the springs are positioned at the end parts close to the second holes;

the top of each die diagonal bar is fixed on the die block, and the distribution mode of many die diagonal bars satisfies: the bottom end of each bottom die diagonal rod extends into the cavity through a first hole at the lower position of the bottom die diagonal rod and is positioned at the same end with a second inclined plane A of the sliding block, and meanwhile, the second inclined plane B is matched with the second inclined plane A;

the top of each top mould diagonal bar is fixed on the top mould, and the distribution mode of many top mould diagonal bars satisfies: the bottom end of each top die inclined rod stretches into the cavity through a second hole at the lower position of the bottom die inclined rod and penetrates through the through hole of the sliding block, the hook surface is partially attached to the bottom surface of the sliding block, and in the process that the top surface inclined rod penetrates through the through hole downwards, the first inclined surface B is matched with the first inclined surface A; the part of the hook surface, which is jointed with the bottom surface of the sliding block, is jointed with an inclined surface.

2. The low pressure casting device according to claim 1, wherein the second inclined plane a, the first inclined plane a, and the inclined plane of the portion where the hook surface is attached to the bottom surface of the slider are different in inclination angle.

3. The low pressure casting apparatus according to claim 1, wherein two slider fixing blocks are installed at both front and rear sides of the top plate assembly.

4. The low pressure casting apparatus of claim 1 wherein the hook is sized to extend a minimum distance to disengage the casting from the bottom die.

5. A low pressure casting apparatus according to claim 3, wherein the minimum distance the casting needs to be separated from the bottom die is 20-40mm.

6. The low pressure casting device according to claim 1, characterized by comprising four reset bars (10) distributed at four apex angle positions of the parting surface of the top die.

7. The low pressure casting device according to claim 1, characterized in that the top plate assembly is assembled from two plates, the top plate assembly is provided with a central through hole (81) for accommodating the liquid lifting sleeve, and the plurality of ejector rods are distributed around the central through hole.

8. The low pressure casting apparatus of claim 1, further comprising a crucible furnace positioned below the lower mold, and wherein the top plate assembly is positioned between the crucible furnace and the lower mold.

9. The low pressure casting apparatus of claim 1, further comprising a low pressure machine and a die opening cylinder, wherein the bottom die and the top surface are both connected to the low pressure machine, and the top die is connected to the die opening cylinder.

10. Synchronous liftout device of low pressure casting mould die block, its characterized in that, liftout device includes:

a top plate assembly (8);

a plurality of sliders (6); the sliding block comprises a sliding block body, a second inclined plane A (62) is arranged on one end face of the sliding block body, a through hole (61) is further formed in the sliding block body, the axial direction of the through hole is parallel to the end face, a first inclined plane A (63) is arranged on one inner side wall of the through hole, and the end face where the second inclined plane A is located is parallel to the inner side face where the first inclined plane A is located;

a plurality of slider fixing blocks (5); the sliding block fixing block comprises a fixing block body, a cavity (51) is formed in the fixing block body, a first hole and a second hole are formed in the fixing block body at the same time, the first hole is communicated with the cavity, the second hole penetrates through the cavity and penetrates through the bottom of the cavity, and the first hole is parallel to the second hole in the axial direction;

a plurality of springs (7);

a plurality of top mold diagonal rods (3); the top die inclined rod comprises a rod body, wherein the bottom end of the rod body is provided with a hook structure, and one side of the bottom surface of the hook is provided with a first inclined plane B;

a plurality of bottom mold diagonal rods (4); the bottom die diagonal bar comprises a body bar, and a second inclined plane B is arranged at the bottom of the body bar;

a plurality of ejector rods (9) and a plurality of reset rods (10);

in the use process, the water-soluble fiber is prepared,

the top plate assembly (8) is arranged below the bottom die, one end of each ejector rod (9) is fixed on the top plate assembly, the other end of each ejector rod penetrates through the bottom die and stretches into the bottom of the die cavity, and the plurality of ejector rods are uniformly distributed at the bottom of the die cavity;

one end of each reset rod (10) is fixed on the top plate assembly, and the other end of each reset rod passes through the bottom die and contacts with the parting surface of the top die;

the sliding block fixing blocks are fixed on the top plate assembly and distributed on the front side and the rear side of the top plate assembly; the sliding block is arranged in the cavity of each sliding block fixing block, the sliding block can move left and right in the cavity, meanwhile, a spring is arranged between one end of the sliding block and the inner wall of the cavity, and the compression direction of the spring is along the movement direction of the sliding block; the first holes and the second holes are distributed along the moving direction of the sliding block, and the springs are positioned at the end parts close to the second holes;

the top of each die diagonal bar is fixed on the die block, and the distribution mode of many die diagonal bars satisfies: the bottom end of each bottom die diagonal rod extends into the cavity through a first hole at the lower position of the bottom die diagonal rod and is positioned at the same end with a second inclined plane A of the sliding block, and meanwhile, the second inclined plane B is matched with the second inclined plane A;

the top of each top mould diagonal bar is fixed on the top mould, and the distribution mode of many top mould diagonal bars satisfies: the bottom end of each top die inclined rod stretches into the cavity through a second hole at the lower position of the bottom die inclined rod and penetrates through the through hole of the sliding block, the hook surface is partially attached to the bottom surface of the sliding block, and in the process that the top surface inclined rod penetrates through the through hole downwards, the first inclined surface B is matched with the first inclined surface A; the part of the hook surface, which is jointed with the bottom surface of the sliding block, is jointed with an inclined surface.