CN110370550B

CN110370550B - Automatic liftout injection moulding mould of desk support frame

Info

Publication number: CN110370550B
Application number: CN201910742522.1A
Authority: CN
Inventors: 陈宇; 庄爱妹
Original assignee: Guangzhou Wangcheng Technology Information Co ltd
Current assignee: Shandong Jiahua New Energy Development Co.,Ltd.
Priority date: 2019-08-13
Filing date: 2019-08-13
Publication date: 2021-05-25
Anticipated expiration: 2039-08-13
Also published as: CN110370550A

Abstract

The invention discloses an automatic ejection injection molding die of a table support frame, which structurally comprises an upper die, a lower die, a base, an ejection mechanism and connecting blocks, wherein the upper die is matched with the lower die, and two sides of the bottom surface of the lower die are connected with the base through the connecting blocks. Through the location slow-falling group, flexible group, the scissors fork, mould the ejecting power unit of piece, mould the combination setting of the ejecting group of piece, make and go up the mould and can slowly fall, take place the rigidity collision with the lower mould when avoiding the compound die, prevent to go up, the lower mould is impaired, avoid going up, the intervalve produces the gap, can not have the air admission when moulding plastics, can avoid moulding the piece gassing, make the intensity of moulding the piece can obtain guaranteeing, it is more firm with the ejecting in-process of injection molding, need not artifical assistance, high efficiency, the dynamics is balanced, can be ejecting with the injection molding can effectively prevent that the liftout plate from keeping the trace on moulding fast, make the quality of moulding the piece can obtain guaranteeing.

Description

Automatic liftout injection moulding mould of desk support frame

Technical Field

The invention relates to the technical field of molds, in particular to an automatic ejection injection molding mold for a table support frame.

Background

The bottom support frame of the existing combined plastic table is X-shaped, and a formed product is obtained by injecting heated and melted plastic into a mold cavity of a mold from an injection molding machine at high pressure, kneading, cooling and solidifying.

The existing injection molding mold has the following defects to be improved due to the incomplete technology:

1) because the upper die and the lower die are made of solid steel materials, the contact surface of the upper die and the lower die can be in rigid collision when the dies are closed, so that the upper die and the lower die are easily abraded, a gap is formed between the closed upper die and the closed lower die after long-time use, air can enter during injection molding, and therefore a plastic part can generate bubbles, and the strength of the injection molding part is further influenced;

2) the ejecting mode of the piece of moulding adopts manual promotion roof, ejector pin ejecting mostly, and ejecting process needs artifical assistance drawing of patterns promptly, and is inefficient, and because of still having the residual heat behind the plastic forming, the difficult control of the dynamics of manual promotion roof, ejector pin, if the dynamics is too big, can produce stress, easily makes roof, ejector pin leave the trace on the injection molding to influence the quality of injection molding, if the dynamics undersize, then can not be ejecting with the injection molding fast.

Disclosure of Invention

The invention mainly aims to overcome the defects of the prior art and provides an automatic ejection injection molding die for a table support frame.

The invention is realized by adopting the following technical scheme: an automatic ejection injection molding die of a table support frame structurally comprises an upper die, a lower die, a base, an ejection mechanism and connecting blocks, wherein the upper die is matched with the lower die;

ejection mechanism is including the location slow group that falls, flexible group, scissors fork, mould the ejecting power unit of piece, mould the ejecting group of piece, the location is slow to fall the group, flexible group, is moulded the ejecting group of piece and all respectively is provided with four groups, it all communicates to mould the ejecting group of piece in four positions in the top of the ejecting power unit of piece, the bottom of the ejecting power unit of piece and the top surface fixed connection of scissors fork to mould, the equal hinged joint in both sides both ends of scissors fork has flexible group, one side that scissors fork was kept away from to flexible group all is connected with the location and slowly falls the group, go up the mould and all slowly fall the group through the location and link together in four bight positions of lower mould, flexible group, scissors fork all are connected with the base, mould the ejecting group of piece and match with the lower mould.

As optimization, the location is slowly fallen the group including locating lever, a location section of thick bamboo, weight balancing piece, spacing ring, insulated wire, guide wire pole, an inboard of a location section of thick bamboo is equipped with the locating lever, and another inboard clearance fit has the weight balancing piece, the weight balancing piece contacts with the spacing ring, the outer wall of spacing ring and the inner wall fixed connection of a location section of thick bamboo, weight balancing piece top is equipped with the guide wire pole that is connected with a location section of thick bamboo inner wall, the one end of insulated wire is connected with the top surface center of weight balancing piece, and the other end passes through guide wire pole and flexible group link, the locating lever is connected with the bottom surface angle position of last mould is perpendicular, a location section of thick bamboo is installed.

As optimization, the positioning cylinder comprises a first cavity, a through hole, a second cavity, a cylinder body and a guide hole, the cylinder body is averagely divided into two cavities, one cavity is the first cavity, the other cavity is the second cavity, the second cavity is communicated with the first cavity through the through hole, the guide hole is formed in the top of one side, away from the first cavity, of the second cavity, the first cavity is matched with the positioning rod, the weight balance block, the limiting ring and the wire guide rod are located in the second cavity, the guide hole is in clearance fit with the insulating wire, and the cylinder body is embedded in the lower die.

As an optimization, the telescopic group comprises a small hole, a first spring, an inner rod and an outer barrel, the inner rod penetrates through the outer barrel and is connected with the outer barrel through the first spring, the outer barrel is provided with the small hole, the insulating wire penetrates through the small hole and the first spring and is connected with the inner rod, and one end, far away from the first spring, of the inner rod is hinged to the scissors fork.

Preferably, the scissor fork comprises an X-shaped hinge frame, a gear and hinge plates, the hinge plates are fixed at four corners of the X-shaped hinge frame, the gear is fixedly connected to the top surface of one hinge rod of the X-shaped hinge frame, the gear is matched with the bottom of the plastic part ejection power set, the hinge plates are hinged to the inner rod, and a central shaft of the type hinge frame is connected with the base through a bearing seat.

As optimization, mould ejecting power unit of piece including gasbag group, ring, pivot, connecting plate, the pivot is gone up the cover and is put the ring that adopts interference fit with it, all be connected with the connecting plate perpendicularly on the ring outer wall quartering position, one side of connecting plate all is connected with gasbag group, the pivot adopts excessive cooperation and bottom surface between them to be tangent setting with the gear, gasbag group communicates in the ejecting group of piece of moulding.

As optimization, the gasbag group is including gasbag, arc urceolus, arc interior pole, the arc urceolus embeds there is the gasbag, the arc interior pole runs through in the arc urceolus and is connected with the gasbag, the gasbag communicates in the ejecting group of piece of moulding.

Preferably, the plastic part ejection assembly comprises an ejection block, a corrugated pipe and a second spring, the second spring connected with the corrugated pipe is arranged in the corrugated pipe, the ejection block is fixed at the top of the corrugated pipe, and the bottom of the corrugated pipe is communicated with the air bag.

Preferably, the long wave corrugated section of the corrugated pipe is connected with a spring ring of a second spring,

preferably, the first cavity and the second cavity are filled with vegetable oil.

Advantageous effects

Compared with the prior art, the invention provides an automatic ejection injection molding mold for a table support frame, which has the following beneficial effects:

(I) according to the invention, through the combined arrangement of the positioning rod, the positioning cylinder and the vegetable oil, the positioning rod and the positioning hole of the existing injection mold are reformed and designed, the positioning rod is designed into a piston type positioning rod, the positioning hole is designed into a double-cavity positioning cylinder with the vegetable oil inside, based on the pressure difference and the principle of a communicating vessel, when the positioning rod retracts towards the positioning cylinder, the vegetable oil in the first cavity flows to the second cavity, the weight balance block rises, so that the upper mold can slowly fall down, the upper mold and the lower mold are prevented from rigidly colliding during mold closing, the upper mold and the lower mold are prevented from being damaged, gaps are prevented from being generated between the upper mold and the lower mold, air cannot enter during injection molding, bubbles can be prevented from being generated in the plastic part, and the;

according to the invention, (II) through the combined arrangement of the positioning slow-falling group, the telescopic group, the scissor fork, the plastic part ejection power group and the plastic part ejection group, when the mold is closed, the upper mold descends to be the main power, the gear drives the circular ring to rotate anticlockwise indirectly through the compression of the hinge frame, so that the air bag extracts the air in the corrugated pipe, the corrugated pipe is compressed, and subsequent injection molding is facilitated.

According to the invention, (III) the corrugated pipe and the second spring are combined, and the spring ring can be increased and reduced at equal intervals when the springs stretch, so that the corrugated section and the corrugated section of the corrugated pipe can be increased or reduced at equal intervals along with the stretching of the second spring, an injection molding piece is ejected more stably without manual assistance, the corrugated pipe is protected, and the service life of the corrugated pipe is prolonged.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

fig. 1 is a schematic structural view of an automatic ejection injection molding mold of a table support frame according to the present invention.

Fig. 2 is a schematic front view of the ejection mechanism of the present invention.

Fig. 3 is a schematic top view of the ejection mechanism according to the first working state of the present invention.

Fig. 4 is a schematic top view of the ejection mechanism of the present invention in a second operating state.

Fig. 5 is a schematic cross-sectional view illustrating a first operating state of the slow drop positioning set according to the present invention.

Fig. 6 is a schematic cross-sectional view illustrating a second working state of the positioning slow-falling group according to the present invention.

Fig. 7 is a schematic cross-sectional view of the telescopic group of the present invention.

Fig. 8 is a schematic cross-sectional structure view of the plastic ejection power unit of the present invention.

Fig. 9 is a schematic cross-sectional structure view of the plastic ejection assembly of the present invention.

In the drawings, the corresponding relationship between the component names and the reference numbers is as follows:

an upper die-1, a lower die-2, a base-3, an ejection mechanism-4, a connecting block-5, a positioning slow-falling group-a, a telescopic group-b, a scissor fork-c, a plastic ejection power group-d, a plastic ejection group-e, a positioning rod-a 1, a positioning cylinder-a 2, a weight balance block-a 3, a limiting ring-a 4, an insulating wire-a 5, a wire guide rod-a 6, a first cavity-a 21, a through hole-a 22, a second cavity-a 23, a cylinder-a 24, a guide hole-a 25, a small hole-b 1, a first spring-b 2, an inner rod-b 3, an outer cylinder-b 4, an X-type hinge frame-c 1, a gear-c 2, a hinge plate-c 3, an air bag group-d 1, a ring-d 2, a rotating shaft-d 3, a connecting plate-d 4, An air bag-d 11, an arc outer cylinder-d 12, an arc inner rod-d 13, an ejection block-e 1, a corrugated pipe-e 2 and a second spring-e 3.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "connected" and "connected" are to be interpreted broadly, e.g., as being fixed or detachable or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Referring to fig. 1-9, the present invention provides a technical solution of an automatic ejecting injection molding mold for a table support frame: the structure of the device comprises an upper die 1, a lower die 2, a base 3, an ejection mechanism 4 and connecting blocks 5, wherein the upper die 1 is matched with the lower die 2, two sides of the bottom surface of the lower die 2 are connected with the base 3 through the connecting blocks 5, and the ejection mechanism 4 connected with the lower die 2 and the base 3 is arranged between the two connecting blocks 5;

ejection mechanism 4 is including the location slowly fall group an, flexible group b, scissors fork c, mould the ejecting power pack d of piece, mould the ejecting group e of piece, the location slowly falls group a, flexible group b, moulds the ejecting group e of piece and all respectively is provided with four groups, mould all the intercommunication in four positions in the top of the ejecting power pack d of piece and mould the ejecting group e of piece, the bottom of the ejecting power pack d of piece and scissors fork c's top surface fixed connection, the equal hinged joint in both sides both ends of scissors fork c has flexible group b, one side that scissors fork c was kept away from to flexible group b all is connected with the location slowly falls group an, go up the mould 1 and link together through location slowly falling group a with four angle positions of lower mould 2, flexible group b, scissors fork c all are connected with base 3, mould the ejecting group e of piece and cooperate with lower mould 2.

The positioning slow-falling group a comprises a positioning rod a1, a positioning cylinder a2, a weight balance a3, a limit ring a4, an insulated wire a5 and a wire guide rod a6, wherein one inner side of the positioning cylinder a2 is provided with a positioning rod a1, the other inner side of the positioning cylinder a2 is movably matched with the weight balance a3, the weight balance a3 is in contact with the limit ring a4, the outer wall of the limit ring a4 is fixedly connected with the inner wall of the positioning cylinder a2, the wire guide rod a6 connected with the inner wall of the positioning cylinder a2 is arranged above the weight balance a3, one end of the insulated wire a5 is connected with the center of the top surface of the weight balance a3, the other end of the insulated wire a 6336 is connected with a telescopic group b through the wire guide rod a6, the positioning rod a1 is vertically connected with the bottom surface of the upper die 1, the positioning cylinder a2 is arranged at the corner of the lower die 2, the positioning slow-falling group a can effectively slow-falling speed, meanwhile, power can be provided for the plastic part ejection group e.

The positioning cylinder a2 comprises a first cavity a21, a through hole a22, a second cavity a23, a cylinder a24 and a guide hole a25, the cylinder a24 is divided into two cavities, one is a first cavity a21, the other is a second cavity a23, the second cavity a23 is communicated with the first cavity a21 through the through hole a22, the top of one side of the second cavity a23, which is far away from the first cavity a21, is provided with the guide hole a25, the first cavity a21 is matched with the positioning rod a1, the weight 3, the limit ring a4 and the wire rod a6 are located in the second cavity a23, the guide hole a25 is in clearance fit with the insulated wire a5, and the cylinder a24 is embedded in the lower die 2.

The telescopic group b comprises a small hole b1, a first spring b2, an inner rod b3 and an outer cylinder b4, the inner rod b3 penetrates through the outer cylinder b4 and is connected with the outer cylinder b4 through a first spring b2, the outer cylinder b4 is provided with a small hole b1, the insulating wire a5 penetrates through the small hole b1 and the first spring b2 and is connected with the inner rod b3, and one end, far away from the first spring b2, of the inner rod b3 is hinged to the scissors fork c.

The scissors fork c comprises an X-shaped hinge frame c1, a gear c2 and a hinge plate c3, wherein the hinge plates c3 are fixed at four corners of the X-shaped hinge frame c1, the gear c2 is fixedly connected to the top surface of a hinge rod of the X-shaped hinge frame c1, the gear c2 is matched with the bottom of a plastic part ejection power set d, the hinge plate c3 is hinged to an inner rod b3, the central shaft of the X-shaped hinge frame c1 is connected with the base 3 through a bearing seat, the scissors fork c is arranged in a mode that the gear c2 rotates anticlockwise when the X-shaped hinge frame c1 is compressed, the air bag set d1 sucks air, the gear c2 rotates clockwise when the X-shaped hinge frame c1 stretches and retracts, and the air bag set d1 inflates air.

Mould ejecting power pack d of piece and including gasbag group d1, ring d2, pivot d3, connecting plate d4, pivot d3 goes up the cover and has put the ring d2 who adopts interference fit with it, all be connected with connecting plate d4 on the ring d2 outer wall quartering position perpendicularly, one side of connecting plate d4 all is connected with gasbag group d1, pivot d3 and gear c2 adopt excessive cooperation and bottom surface between them is tangent setting, gasbag group d1 communicates in the ejecting group e of piece of moulding.

The airbag group d1 comprises an airbag d11, an arc-shaped outer cylinder d12 and an arc-shaped inner rod d13, an airbag d11 is arranged in the arc-shaped outer cylinder d12, the arc-shaped inner rod d13 penetrates through the arc-shaped outer cylinder d12 and is connected with the airbag d11, the airbag d11 is communicated with a plastic part ejection group e, the airbag group d1 is arranged in a manner that the arc-shaped inner rod d13 extends outwards, the airbag d11 inhales air, the arc-shaped inner rod d13 contracts inwards, the airbag d11 inflates air, and therefore the plastic part ejection group e can eject out a plastic part.

The plastic piece ejection group e comprises an ejection block e1, a corrugated pipe e2 and a second spring e3, the second spring e3 connected with the corrugated pipe e2 is arranged in the corrugated pipe e2, an ejection block e1 is fixed at the top of the corrugated pipe e2, the bottom of the corrugated pipe e2 is communicated with an air bag d11, the corrugated pipe e2 has a telescopic function, can be retracted after air suction so that injection molding can be normally carried out, and can be extended outwards to eject a plastic piece when air penetrates inwards.

The long corrugated node of the corrugated pipe e2 is connected with the spring ring of the second spring e3, so that the corrugated node and the corrugated energy of the corrugated pipe e2 are increased or reduced at equal intervals along with the expansion and contraction of the second spring e3, the corrugated pipe e2 is protected, and the service life of the corrugated pipe e2 is prolonged.

Vegetable oil is arranged in the first cavity a21 and the second cavity a23, when the positioning rod a1 retracts towards the positioning cylinder a2, the vegetable oil in the first cavity a21 flows to the second cavity a23 based on the principle of a communicating vessel, and when the positioning rod a1 extends towards the positioning cylinder a2, the vegetable oil in the second cavity a2 flows to the first cavity a 21.

The working principle of the invention is as follows: when the die is closed, the positioning rod a1 retracts towards the positioning cylinder a2, the volume of the vegetable oil in the first cavity a21 is reduced, the retraction amount of the positioning rod a1 towards the positioning cylinder a2 is in proportion to the amount of the vegetable oil flowing from the through hole a22 to the second cavity a23, so that the weight balance a3 rises under the thrust of the vegetable oil, the rise amount of the weight balance a3 is in proportion to the amount of the vegetable oil flowing to the second cavity a23, the weight a3 rises to release the pulling force on the inner rod b3, the first spring b2 is reduced in pulling force to provide the pushing force on the inner rod b3 due to the pulling and retracting, so that the b3 moves towards the inner rod b4 of the outer cylinder b, so that the b3 extends to generate pressure on the X-shaped hinge frame c1, so that the X-shaped hinge frame c1 rotates and compresses around the central axis thereof, thereby rotating the gear c2 counterclockwise, the connecting plate 4 drives the arc 13 to extend towards the arc outer cylinder d12, thereby stretching the air suction bag 11, the gas in the bellows e2 is pumped out, so that the second spring e3 is not stressed and is stretched to reset to generate pulling force on the bellows e2, and the bellows e2 is reset;

when the mold is opened, the positioning rod a1 extends to the positioning cylinder a2, the volume of the first cavity a21 is increased, the vegetable oil in the second cavity a23 flows to the first cavity a21 through the through hole a22 based on the principle of a communicating vessel, so that the weight balance a3 is stressed to be reduced and descends due to self weight, the descending amount of the weight balance a3 is in direct proportion to the amount of vegetable oil flowing to the first cavity a21, the descending amount of the weight balance a3 generates tension on the inner rod b3, the first spring b2 is pulled and contracted, the inner rod b3 retracts towards the outer cylinder b4, so that the inner lever b3 generates a pulling force on the X-shaped hinge bracket c1, so that the X-shaped hinge bracket c1 rotates around the central axis thereof as an axis to stretch and unfold, so that the gear c2 rotates clockwise, the connecting plate d4 drives the arc inner rod d13 to retract towards the arc outer cylinder d12, therefore, the air bag d11 is compressed to discharge air, air penetrates into the bellows e2, the second spring e3 is stretched, and the bellows e2 drives the ejection block e1 to extend outwards to eject the plastic part.

In summary, the technical progress obtained by the invention compared with the prior art is as follows:

1) according to the invention, through the combined arrangement of the positioning rod, the positioning cylinder and the vegetable oil, the positioning rod and the positioning hole of the existing injection mold are reformed and designed, the positioning rod is designed into a piston type positioning rod, the positioning hole is designed into a double-cavity positioning cylinder with the vegetable oil inside, based on the pressure difference and the principle of a communicating vessel, when the positioning rod retracts towards the positioning cylinder, the vegetable oil in the first cavity flows to the second cavity, the weight balance block rises, so that the upper mold can slowly fall down, the upper mold and the lower mold are prevented from rigidly colliding during mold closing, the upper mold and the lower mold are prevented from being damaged, gaps are prevented from being generated between the upper mold and the lower mold, air cannot enter during injection molding, bubbles can be prevented from being generated in the plastic part, and the;

2) according to the invention, through the combined arrangement of the positioning slow-falling set, the telescopic set, the scissors fork, the plastic part ejection power set and the plastic part ejection set, when the mold is closed, the upper mold is lowered into the main power, the gear drives the circular ring to rotate anticlockwise indirectly through the compression of the hinge frame, so that the air bag pumps the air in the corrugated pipe, the corrugated pipe is compressed, and the subsequent injection molding is facilitated.

3) According to the invention, through the combination of the corrugated pipe and the second spring, the spring ring and the spring ring can be increased and reduced at equal intervals when the spring stretches, so that the corrugated section and the corrugation of the corrugated pipe can be increased or reduced at equal intervals along with the stretching of the second spring, an injection molding piece is ejected more stably without manual assistance, the corrugated pipe is protected, and the service life of the corrugated pipe is prolonged.

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes in the embodiments and/or modifications of the invention can be made, and equivalents and modifications of some features of the invention can be made without departing from the spirit and scope of the invention.

Claims

1. The utility model provides an automatic liftout injection moulding mould of desk support frame, its structure includes mould (1), lower mould (2), base (3), ejection mechanism (4), connecting block (5), it cooperatees with lower mould (2) to go up mould (1), lower mould (2) are connected its characterized in that through ejection mechanism (4), connecting block (5) and base (3):

the ejection mechanism (4) comprises a positioning slow-falling group (a), a telescopic group (b), a scissor fork (c), a plastic ejection power group (d) and a plastic ejection group (e), the top of the plastic ejection power group (d) is communicated with four plastic ejection groups (e), the bottom of the plastic ejection power group is connected with the scissor fork (c), the scissor fork (c) is connected with the positioning slow-falling group (a) through the telescopic group (b), and the upper die (1) is connected with the lower die (2) through the positioning slow-falling group (a);

the positioning slow-falling group (a) comprises a positioning rod (a1), a positioning cylinder (a2), a weight balance block (a3), a limiting ring (a4), an insulating wire (a5) and a wire guide rod (a6), wherein a positioning rod (a1), a weight balance block (a3), a limiting ring (a4) and a wire guide rod (a6) are arranged in the positioning cylinder (a2), one end of the insulating wire (a5) is connected with the weight balance block (a3), and the other end of the insulating wire (a5) is connected with the telescopic group (b);

the positioning cylinder (a2) comprises a first cavity (a21), a through hole (a22), a second cavity (a23), a cylinder body (a24) and a guide hole (a25), wherein the first cavity (a21) and the second cavity (a23) are communicated through the through hole (a22) in the cylinder body (a24), the second cavity (a23) is provided with the guide hole (a25), the first cavity (a21) is matched with the positioning rod (a1), the guide hole (a25) is matched with an insulating wire (a5), and the cylinder body (a24) is embedded in the lower die (2);

the telescopic group (b) comprises a small hole (b1), a first spring (b2), an inner rod (b3) and an outer cylinder (b4), the inner rod (b3) penetrates through the outer cylinder (b4) to be connected with the first spring (b2), the outer cylinder (b4) is provided with the small hole (b1), and the inner rod (b3) is connected with an insulating wire (a5) and a scissor fork (c);

the scissors fork (c) comprises an X-shaped hinge frame (c1), a gear (c2) and a hinge plate (c3), wherein four hinge plates (c3) are fixed on the X-shaped hinge frame (c1), one gear (c2) is arranged, the gear (c2) is matched with a plastic part ejection power set (d), and the hinge plate (c3) is connected to an inner rod (b 3);

the plastic part ejection power group (d) comprises an air bag group (d1), a circular ring (d2), a rotating shaft (d3) and a connecting plate (d4), wherein the rotating shaft (d3) is provided with the circular ring (d2) with the connecting plate (d4), the connecting plate (d4) is connected with the air bag group (d1), the rotating shaft (d3) is matched with the gear (c2), and the air bag group (d1) is communicated with a plastic part ejection group (e);

the airbag group (d1) comprises an airbag (d11), an arc-shaped outer cylinder (d12) and an arc-shaped inner rod (d13), an airbag (d11) connected with the arc-shaped inner rod (d13) is arranged in the arc-shaped outer cylinder (d12), and the airbag (d11) is communicated with the plastic part ejection group (e);

the plastic part ejection group (e) comprises an ejection block (e1), a corrugated pipe (e2) and a second spring (e3), wherein the corrugated pipe (e2) is connected with the ejection block (e1) at the upper part, connected with the air bag (d11) at the lower part and internally provided with the second spring (e 3).