CN113263144A

CN113263144A - Cold box core shooter

Info

Publication number: CN113263144A
Application number: CN202110609433.7A
Authority: CN
Inventors: 王绍希
Original assignee: Xiangshan Lianqiang Automotive Mould Co ltd
Current assignee: Xiangshan Lianqiang Automotive Mould Co ltd
Priority date: 2021-06-01
Filing date: 2021-06-01
Publication date: 2021-08-17
Anticipated expiration: 2041-06-01
Also published as: CN113263144B

Abstract

The application discloses a cold core box core shooter, which comprises a workbench, a lower die holder, a movable die, an upper die plate and a sand core, wherein the lower die holder is arranged on the workbench, the lower die holder, the movable die and the upper die plate can be matched to form a core box, and the sand core is accommodated in the core box; the movable mould comprises an end mould and side moulds, the end mould is detachably arranged at two ends of the core box, the end mould can be matched with the lower die holder to form the end part of the core box, the side moulds are detachably arranged at two sides of the core box, and the end mould can be clamped and matched with the lower die holder to form the side wall of the core box; be provided with mold opening device on the die holder, mold opening device includes first drive assembly, second drive assembly, guide post and guide rod, and first drive assembly can control the end mould and remove along the axial of core box, and second drive assembly can control the side mould and remove along the radial of core box, and this core shooting machine is small compact structure, can be automatic and quick carry out the die sinking compound die operation, and the product surface of producing is smooth, and the planarization is high.

Description

Cold box core shooter

Technical Field

The application relates to the technical field of mold casting equipment, in particular to a cold box core shooter.

Background

The core shooter is a device that uses compressed air to uniformly inject the molding sand into the flask for pre-compaction, and then applies pressure to compact the molding sand. Core shooters are widely used in recent years, and high molding wages can be saved by using the core shooter for molding. Because the waste of a casting head can be reduced by stacking and pouring the multiple boxes, the collapsibility of the coated sand after pouring is good, and the sand cleaning is facilitated. In addition, the core shooter has high production efficiency and accurate size of the sand mold, and can properly reduce the processing amount; the operation is simple and convenient, the casting yield is high, and more foundries begin to favor the use of the core shooting machine for modeling.

The core shooter adopts precoated sand to make cores, and is suitable for both hot core boxes and cold core boxes. The core shooting machine has the working principle that a core-sand mixture taking liquid or solid thermosetting resin as a binder is shot into a heated core box, a sand core is preheated in the core box and quickly hardened to a certain thickness (about 5-10 mm), and the sand core is taken out, so that a high-quality sand core finished product with a smooth surface and an accurate size is formed.

However, the existing core shooter has the following disadvantages:

1. in order to increase the production efficiency, the core shooter generally has an automatic die opening and closing structure, but the core shooter with the automatic die opening and closing structure has a large volume and occupies a large space.

2. After the core shooter is used for shooting the sand in the mold, the residual molding sand in the sand shooting channel can form waste materials, the mold opening difficulty of the mold is increased, and the waste materials at the position need to be processed after the mold opening, so that the production efficiency is influenced.

3. Because the mould on the core shooter is combined and fixed by the mould opening and closing structure, if the product size is large, the structure is complex, installation errors can occur after combination, and meanwhile, extrusion and impact can be caused to the mould during sand shooting forming, the combination stability of the mould is influenced, and the quality of the product is finally influenced.

Disclosure of Invention

An object of this application provides a volume is less, compact structure, can be automatic and quick carry out die sinking compound die operation, and the product surface of producing is smooth, cold-box core shooter that the planarization is high.

In order to achieve the above purposes, the technical scheme adopted by the application is as follows: a cold core box core shooter comprises a workbench, a lower die holder, a movable die, an upper die plate and a sand core, wherein the lower die holder is arranged on the workbench, the lower die holder, the movable die and the upper die plate can be matched to form a core box, and the sand core is accommodated in the core box;

the movable mould comprises an end mould and side moulds, the end mould is detachably arranged at two ends of the core box, the end mould can be matched with the lower die holder to form the end part of the core box, the side moulds are detachably arranged at two sides of the core box, and the end mould can be clamped and matched with the lower die holder to form the side wall of the core box;

the lower die base is provided with a die sinking device which comprises a first driving component, a second driving component, a guide post and a guide rod, the first driving component is arranged on the workbench and connected with the end mold, the first driving component can control the end mold to move along the axial direction of the core box, the guide posts are arranged at two sides of the lower die holder, the guide rods are arranged in parallel with the first driving component, one end of the guide rod is fixedly connected with the end die, the other end of the guide rod penetrates through the lower die holder and is connected with the guide column in a sliding manner, the second driving assembly is arranged below the guide rod and can control the side die to move along the radial direction of the core box, when the second driving assembly controls the side die to open, the guide column can limit the opening range of the side die.

As an improvement, the upper template is provided with a sand shooting channel communicated to the sand core, the upper template is provided with a flattening device, the flattening device comprises an installation platform, an upper pressure plate and a pressure rod, the installation platform can be lifted and arranged above the upper template, the installation platform is provided with a sand shooting nozzle, the sand shooting nozzle is matched with the sand shooting channel, the upper pressure plate can be lifted and arranged above the installation platform, the pressure rod is arranged on the upper pressure plate, when the lower pressure plate descends, the pressure rod can penetrate through the sand shooting nozzle to be pushed to the sand core, and the shape of the bottom end of the pressure rod is matched with the outer surface of the sand core.

As an improvement, still be provided with in the core box with the psammitolite complex takes out the piece, the installing port has been seted up at the die holder both ends, the end mould can peg graft to in the installing port with take out the both ends cooperation joint of piece, take out the piece both sides and seted up the joint piece, be provided with the cooperation on the side mould the joint groove of joint piece.

Specifically, set up in the workstation and hold the chamber, it is provided with the liftout device to hold the intracavity, the liftout device includes slide bar, ejector plate and ejector rod, the slide bar set up in the bottom of die holder, the ejector plate with slide bar sliding connection, the ejector rod fixed set up in on the ejector plate, the ejector rod can pass the die holder top extremely the psammitolite, the workstation has seted up all around and has observed the window of liftout device.

As an improvement, the bottom of cope match-plate pattern is provided with a plurality of locking pieces and reference column, the cooperation joint has been seted up on the movable mould the locking groove of locking piece, the reference column set up respectively in the four corners of cope match-plate pattern, the both sides cutting of reference column forms the locating surface, adjacent two on the reference column the orientation of locating surface is different, the cooperation has been seted up on the die holder the locating hole of reference column.

As an improvement, a strengthening rod penetrates through the inside of the sand core, two ends of the strengthening rod extend out of the sand core, a supporting table extending into the core box is arranged on the lower die base, and the supporting table is matched and fixed with two ends of the strengthening rod.

As an improvement, the internal diameter of shooting mouth is from last to shrinking gradually down and forming infundibulate structure, the mount table with be provided with the buffering reset assembly between the top board, the buffering reset assembly includes bracing piece and elasticity piece that resets, the both ends of bracing piece respectively with the mount table with top board sliding connection, elasticity resets the cover and locates make on the bracing piece the mount table with the top board can keep away from each other.

As an improvement, the drawing block can be disconnected from the middle part to realize separation, and the outer diameters of the two ends of the drawing block are not smaller than the outer diameter of the middle part of the drawing block.

As an improvement, an auxiliary sliding rail is arranged below the side die and is fixedly arranged along the die opening direction of the side die.

As an improvement, the first driving assembly comprises a long air cylinder, the long air cylinders on the same side are connected with each other to form a guardrail, the second driving assembly comprises a short air cylinder, and a cushion pad facing the lower die holder is arranged on the end die.

Compared with the prior art, the beneficial effect of this application lies in:

1. carry out configuration optimization with the mold opening device of end mould and side mould, increased the stability of structure when reducing occupation space, can be automatic and quick carry out the die sinking compound die operation, the structural guide post of die sinking can enough regard as guide structure simultaneously, increases the die sinking stability of end mould, can also regard as limit structure, limits the die sinking scope of offside mould, causes the impact to second drive assembly when avoiding the side mould die sinking, influences life.

2. In order to promote machining efficiency, set up flattening device on the cope match-plate pattern, flattening device can flatten the surface along the psammitolite to the waste material of penetrating in the sand passageway after penetrating the sand operation and accomplishing, can enough increase the degree of compactness of molding sand, also can avoid forming the waste material, reduce subsequent processing degree of difficulty, promote production efficiency, still be provided with the buffering reset assembly on the flattening device, the buffering reset assembly can restrict the pushing down position of depression bar, avoid excessively pushing down, damage the product, after pushing down the completion, still can reset to the position of depression bar.

3. Be provided with multiple locking and positioner between each mould, the side form mould with take out the piece and pass through joint groove and joint piece and be connected, it can be direct to peg graft with the end mould to take out the piece, the movable mould locks through locking groove and locking piece with the cope match-plate pattern, die holder and cope match-plate pattern are fixed a position through locating hole and reference column, it is provided with the bracing piece to run through in the psammitolite, the mould makes up to have high stability behind the core box, each position is connected closely, can not take place the skew and warp, above-mentioned structure makes the die sinking process can only carry out the die sinking according to the order, each mould can not take place to break away from in advance, prevent damaging the product.

Drawings

FIG. 1 is a perspective view of a preferred embodiment according to the present application;

FIG. 2 is a front view of a preferred embodiment according to the present application;

FIG. 3 is a cross-sectional view taken along the line A-A of FIG. 2, in accordance with a preferred embodiment of the present application;

fig. 4 is a structural view of a moving mold in a clamped state according to a preferred embodiment of the present application;

FIG. 5 is a structural view of a moving mold in an open state according to a preferred embodiment of the present application;

FIG. 6 is a structural view of the bottom of the upper platen according to a preferred embodiment of the present application;

FIG. 7 is an enlarged view at a in FIG. 3 according to a preferred embodiment of the present application;

FIG. 8 is an enlarged view at b of FIG. 6 in accordance with a preferred embodiment of the present application;

fig. 9 is an enlarged view at c of fig. 5 according to a preferred embodiment of the present application.

In the figure: 1. a work table; 11. a window; 2. a lower die holder; 21. an installation port; 22. positioning holes; 23. a support table; 3. moving the mold; 31. an end mold; 311. a cushion pad; 32. a side mold; 321. a clamping groove; 322. an auxiliary slide rail; 33. a locking groove; 4. mounting a template; 41. a sand shooting channel; 42. extracting blocks; 421. a clamping block; 43. a locking block; 44. a positioning column; 441. positioning the surface; 5. a sand core; 51. a reinforcing rod; 6. a mold opening device; 61. a first drive assembly; 62. a second drive assembly; 63. a guide post; 64. a guide rod; 7. a flattening device; 71. an installation table; 711. a sand shooting nozzle; 72. pressing a plate; 73. a pressure lever; 731. a concave arc surface; 74. a buffer reset component; 741. a support bar; 742. an elastic reset member; 8. a material ejecting device; 81. a slide bar; 82. a material ejecting plate; 83. and a material ejecting rod.

Detailed Description

The present application is further described below with reference to specific embodiments, and it should be noted that, without conflict, any combination between the embodiments or technical features described below may form a new embodiment.

In the description of the present application, it should be noted that, for the terms of orientation, such as "central", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., it indicates that the orientation and positional relationship shown in the drawings are based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, but does not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be construed as limiting the specific scope of protection of the present application.

It is noted that the terms first, second and the like in the description and in the claims of the present application are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.

The terms "comprises," "comprising," and "having," and any variations thereof, in the description and claims of this application, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The present application is further described with reference to the accompanying drawings:

as shown in fig. 1 to 5, a preferred embodiment of the present application includes a workbench 1, a lower die holder 2, a movable die 3, an upper die plate 4 and a sand core 5, the lower die holder 2 is disposed on the workbench 1, the lower die holder 2, the movable die 3 and the upper die plate 4 can be matched to form a core box, the sand core 5 is accommodated in the core box, the lower die holder 2, the movable die 3, the upper die plate 4 and the sand core 5 form a basic die structure, and the design can be performed according to different product shapes, so as to ensure that the die and the product do not interfere when the die is opened and closed.

As shown in fig. 4 to 5, the movable mold 3 includes an end mold 31 and side molds 32, the end mold 31 is detachably disposed at two ends of the core box, the end mold 31 can cooperate with the lower mold base 2 to form an end portion of the core box, the side molds 32 are detachably disposed at two sides of the core box, the end mold 31 can cooperate with the lower mold base 2 to form a sidewall of the core box, and the movable mold can be suitable for casting a relatively complex mold, especially a product with a cylindrical structure, and can enable both the end portion and the two sides of the product to be precisely formed.

Be provided with mold opening device 6 on die holder 2, mold opening device 6 is used for assisting movable mould 3 to realize automatic die sinking compound die, mold opening device 6 includes first drive assembly 61, second drive assembly 62, guide post 63 and guide bar 64, first drive assembly 61 sets up on workstation 1 and is connected with end mould 31, first drive assembly 61 can control end mould 31 and remove along the axial of core box, guide post 63 sets up in die holder 2 both sides, guide bar 64 and first drive assembly 61 parallel arrangement, guide bar 64 one end and end mould 31 fixed connection, the guide bar 64 other end passes die holder 2 and with guide post 63 sliding connection, second drive assembly 62 sets up in the below of guide bar 64, second drive assembly 62 can control side mould 32 and remove along the radial of core box.

End mould 31 can form the extension structure through first drive assembly 61 and guide rod 64, avoids first drive assembly 61 to bear great pressure when the die sinking and leads to the deformation to damage, can promote stability in use and life, and second drive assembly 62 sets up in guide rod 64 below, through vertically placing reduction equipment volume, makes the structure compacter when realizing the quadriversal die sinking structure.

Because second drive assembly 62 sets up in the die sinking direction of side form 32, and the weight of side form 32 is great, and side form 32 probably causes the impact to second drive assembly 62 because of inertia when opening the die, and guide post 63 can support side form 32 as limit structure this moment, and the die sinking scope of side form 32 is restricted, avoids side form 32 to cause the impact to second drive assembly 62 simultaneously, influences life.

As shown in fig. 3, a sand shooting channel 41 communicated to a sand core 5 is formed in an upper template 4, a flattening device 7 is arranged on the upper template 4, the flattening device 7 comprises an installation platform 71, an upper pressure plate 72 and a pressure lever 73, the installation platform 71 can be arranged in a lifting manner and above the upper template 4, a sand shooting nozzle 711 is arranged on the installation platform 71, the sand shooting nozzle 711 is matched with the sand shooting channel 41, the upper pressure plate 72 can be arranged above the installation platform 71 in a lifting manner, the pressure lever 73 is arranged on the upper pressure plate 72, when the lower pressure plate 72 descends, the pressure lever 73 can penetrate through the sand shooting nozzle 711 to push the sand core 5, the flattening device 7 can flatten waste materials in the sand shooting channel 41 along the outer surface of the sand core 5 after sand shooting operation is completed, not only can the compactness of molding sand be increased, but also waste materials can be avoided being formed, subsequent processing difficulty is reduced, and production efficiency is improved.

The buffering reset assembly 74 is arranged between the mounting table 71 and the upper pressing plate 72, the buffering reset assembly 74 comprises a supporting rod 741 and an elastic reset piece 742, the elastic reset piece 742 preferably uses a pressure spring, the structure is simple, the installation is convenient, two ends of the supporting rod 741 are respectively in sliding connection with the mounting table 71 and the upper pressing plate 72, the elastic reset piece 742 is sleeved on the supporting rod 741 to enable the mounting table 71 and the upper pressing plate 72 to be away from each other, the buffering reset assembly 74 can limit the pressing position of the pressing rod 73, excessive pressing is avoided, the position of the pressing rod 73 can be reset after pressing is completed, in addition, the minimum telescopic amplitude of the elastic reset piece 742 can be set to enable the pressing rod 73 to just push against the tail end of the sand shooting channel 41, and damage to products is avoided.

Set up in the workstation 1 and hold the chamber, it is provided with liftout device 8 to hold the intracavity, liftout device 8 includes slide bar 81, ejector plate 82 and ejector bar 83, slide bar 81 sets up in the bottom of die holder 2, ejector plate 82 and slide bar 81 sliding connection, ejector bar 83 is fixed to be set up on ejector plate 82, ejector bar 83 can pass die holder 2 top to psammitolite 5, the height of workstation 1 can be promoted in this design, accord with the operation custom of operative employee, and utilize the space of workstation 1 below, reduce the equipment volume, realize automatic liftout simultaneously, reduce the operation degree of difficulty of the ejection of compact, workstation 1 has seted up the window 11 that can observe liftout device 8 all around. Conveniently observe the function of liftout device 8, also can conveniently overhaul, can subtract heavy by workstation 1 simultaneously.

As shown in fig. 7, the concave arc surface 731 is arranged on the outer surface of the sand core 5 matched with the shape at the bottom end of the pressing rod 73, the sand channel 41 can be extruded by molding sand, the surface of a formed product is smoother, extra waste removal operation is not needed, the processing efficiency is increased, the inner diameter of the sand shooting nozzle 711 gradually shrinks from top to bottom to form a funnel-shaped structure, the pressing rod 73 can be guided to enter the sand shooting nozzle 711, and the pressing stability of the pressing rod 73 is improved.

As shown in fig. 3 to 5, still be provided with in the core box with 5 complex of psammitolite and take out piece 42, it is used for filling the supplementary of core box inner structure to take out piece 42, make things convenient for the product shaping, installing port 21 has been seted up at lower bolster 2 both ends, end mould 31 can be pegged graft in installing port 21 and take out the both ends cooperation joint of piece 42, it has seted up joint piece 421 to take out piece 42 both sides, be provided with the joint groove 321 of cooperation joint piece 421 on the side form 32, it all uses solitary structure to fix with end mould 31 and side form 32 to take out piece 42, promote joint strength and stability between each mould.

As shown in fig. 4 to 6, the bottom of the upper mold plate 4 is provided with a plurality of locking blocks 43 and positioning posts 44, the movable mold 3 is provided with locking slots 33 for engaging with the locking blocks 43, the positioning posts 44 are respectively disposed at four corners of the upper mold plate 4, and the lower mold base 2 is provided with positioning holes 22 for engaging with the positioning posts 44. Be provided with locking structure on cope match-plate pattern 4 and lock moving die utensil 3, before cope match-plate pattern 4 was opened, moving die utensil 3 can't carry out the die sinking in advance, ensures can not cause the damage to the product

As shown in fig. 8, two sides of the positioning posts 44 are cut to form positioning surfaces 441, and the positioning surfaces 441 on two adjacent positioning posts 44 have different orientations, so that the upper template 4 is convenient to mount and position, the mounting direction error of the upper template 4 is avoided, and the efficiency reduction caused by misoperation is reduced.

As shown in fig. 3, the reinforcing rod 51 is inserted into the sand core 5, and when the volume of the product casting is large, the volume of the sand core 5 is also large, so the reinforcing rod 51 is arranged in the sand core 5 to reinforce the structure of the sand core 5, thereby avoiding the breakage and damage of the sand core 5.

As shown in fig. 9, both ends of the reinforcing rod 51 extend out of the sand core 5, the lower die holder 2 is provided with a support platform 23 extending into the core box, the support platform 23 is matched with and fixes both ends of the reinforcing rod 51, the sand core 5 is supported by the support platform 23, the movement of the sand core 5 is avoided, and the installation stability is increased.

As shown in fig. 4 to 5, the pulling block 42 can be separated from the middle of the pulling block 42, and the outer diameters of the two ends of the pulling block 42 are not smaller than the outer diameter of the middle of the pulling block 42.

The auxiliary slide rail 322 is arranged below the side die 32, the auxiliary slide rail 322 is fixedly arranged along the die opening direction of the side die 32, and the auxiliary slide rail 322 can help the side die 32 to open and close the die due to the fact that the side die 32 is heavy in weight, burden of the second driving assembly 62 is reduced, and structural stability and service life are improved.

First drive assembly 61 preferably uses long cylinder, and the long cylinder interconnect with one side forms the guardrail, can play the protection and shelter from the effect, increases space utilization, and second drive assembly 62 preferably uses short cylinder, is provided with the blotter 311 towards die holder 2 on the end mould 31, and the blotter 311 can reduce the impact of end mould 31 to die holder 2 at the compound die in-process, reduces the wearing and tearing of mould, promotes life.

The foregoing has described the general principles, essential features, and advantages of the application. It will be understood by those skilled in the art that the present application is not limited to the embodiments described above, which are merely illustrative of the principles of the application, but that various changes and modifications may be made without departing from the spirit and scope of the application, and these changes and modifications are intended to be within the scope of the application as claimed. The scope of protection claimed by this application is defined by the following claims and their equivalents.

Claims

1. A cold box core shooter is characterized in that: the sand core forming machine comprises a workbench, a lower die holder, a movable die, an upper die plate and a sand core, wherein the lower die holder is arranged on the workbench, the lower die holder, the movable die and the upper die plate can be matched to form a core box, and the sand core is contained in the core box;

2. A cold box core shooter as claimed in claim 1 wherein: the sand core injection molding device is characterized in that a sand injection channel communicated to the sand core is formed in the upper template, a flattening device is arranged on the upper template and comprises an installation platform, an upper pressing plate and a pressing rod, the installation platform can be lifted and arranged above the upper template, a sand injection nozzle is arranged on the installation platform and matched with the sand injection channel, the upper pressing plate can be lifted and arranged above the installation platform, the pressing rod is arranged on the upper pressing plate, when the lower pressing plate descends, the pressing rod can penetrate through the sand injection nozzle to be pushed to the sand core, and the shape of the bottom end of the pressing rod is matched with the outer surface of the sand core.

3. A cold box core shooter as claimed in claim 1 wherein: the core box is internally provided with a pulling block matched with the sand core, mounting ports are formed in two ends of the lower die holder, the end die can be inserted into the mounting ports and is clamped with the two ends of the pulling block in a matched mode, clamping blocks are formed in two sides of the pulling block, and clamping grooves matched with the clamping blocks are formed in the side die.

4. A cold box core shooter as claimed in claim 1 wherein: the utility model discloses a sand core ejecting device, including workstation, ejector pin, the workstation is seted up all around and is held the chamber, it is provided with the liftout device to hold the intracavity, the liftout device includes slide bar, ejector plate and ejector pin, the slide bar set up in the bottom of die holder, the ejector plate with slide bar sliding connection, the ejector pin fixed set up in on the ejector plate, the ejector pin can pass the die holder top extremely the psammitolite, the workstation has seted up all around and has observed the window of liftout device.

5. A cold box core shooter as claimed in claim 1 wherein: the bottom of cope match-plate pattern is provided with a plurality of locking pieces and reference column, the cooperation joint has been seted up on the movable mould the locking groove of locking piece, the reference column set up respectively in the four corners of cope match-plate pattern, the both sides cutting of reference column forms the locating surface, adjacent two on the reference column the orientation of locating surface is different, the cooperation has been seted up on the die holder the locating hole of reference column.

6. A cold box core shooter as claimed in claim 1 wherein: the sand core is internally provided with a reinforcing rod in a penetrating manner, two ends of the reinforcing rod extend out of the sand core, the lower die base is provided with a supporting table extending into the core box, and the supporting table is matched and fixed with two ends of the reinforcing rod.

7. A cold box core shooter as claimed in claim 2 wherein: the internal diameter of sand shooting mouth is from last to shrinking gradually down and forming infundibulate structure, the mount table with be provided with the buffering reset assembly between the top board, the buffering reset assembly includes bracing piece and elasticity piece that resets, the both ends of bracing piece respectively with the mount table with top board sliding connection, elasticity resets and overlaps and locates make on the bracing piece the mount table with the top board can keep away from each other.

8. A cold box core shooter as claimed in claim 3 wherein: the drawing block can be disconnected from the middle part to realize separation, and the outer diameters of the two ends of the drawing block are not smaller than the outer diameter of the middle part of the drawing block.

9. A cold box core shooter as claimed in claim 1 wherein: and an auxiliary sliding rail is arranged below the side die and is fixedly arranged along the die opening direction of the side die.

10. A cold box core shooter as claimed in claim 1 wherein: the first driving assembly comprises a long air cylinder, the long air cylinders are connected with each other to form a guardrail, the second driving assembly comprises a short air cylinder, and a cushion pad facing the lower die holder is arranged on the end die.