Pneumatic demolding device for plastic mold

Abstract

The pneumatic demolding device for the plastic mold belongs to the technical field of demolding devices and comprises a lower mold and a protruding part fixedly arranged on the top end face of the lower mold, a top plate is movably arranged on the top end face of the lower mold, an ejector rod is arranged below the top plate, and a guide hole matched with the ejector rod is formed in the top end face of the lower mold; through the cooperation of the arranged jacking part and the sliding frame, the sliding frame can drive the jacking rod and the jacking plate to move upwards by a small distance in the process of sliding along the annular groove, so that a formed product can be quickly and stably jacked up from the protruding part, and in the process of further jacking up the jacking plate by the jacking rod, the formed product can be quickly and stably jacked up. The sliding frame can return to one side of the positioning plate again to be reset, so that continuous use of the device is facilitated, and compared with a traditional pneumatic demolding mode, the structure can still stably conduct demolding under the condition that a formed product is severely bonded with the protruding part.

Description

Technical Field

[0001] The invention relates to the technical field of demoulding devices, and in particular to a pneumatic demoulding device for a plastic mold. Background Art

[0002] An injection mold is a tool for producing plastic products; it is also a tool that gives plastic products a complete structure and precise dimensions. Specifically, it refers to the process of injecting heated and molten plastic into a mold cavity under high pressure by an injection molding machine, and then cooling and solidifying to obtain a molded product.

[0003] Chinese patent CN217395611U discloses an injection mold with a pneumatic demolding structure, which pushes the pneumatic rod and the ejector block by injecting gas into the main airway and the branch airway respectively, so that the ejector block can push the side wall of the product to demold, and the pneumatic rod can drive the ejector rod to push the bottom of the product through the cross plate to complete the demolding, finally facilitating the removal of the product from the mold body.

[0004] The above-mentioned device applies power to the ejector pin through the pneumatic structure, thereby pushing the plastic product out through the ejector pin. However, in actual use, due to factors such as the rough inner wall of the mold cavity or the mold temperature being too high, the plastic product may stick to the mold. At this time, a large amount of gas will accumulate under the ejector pin. When the injection molded product is separated from the mold, the rapid release of gas will cause the ejector pin to move upward too quickly, which is not conducive to the stable demolding of the injection molded product. In summary, the above-mentioned device still has room for improvement.

[0005] Therefore, it is necessary to provide a pneumatic demoulding device for plastic molds to solve the above technical problems. Summary of the invention

[0006] The object of the present invention is to provide a pneumatic demolding device for a plastic mold, so as to solve the problem that the existing device proposed in the above background technology applies power to the ejector pin by means of a pneumatic structure, thereby pushing out the plastic product through the ejector pin. However, in actual use, due to factors such as the rough inner wall of the mold cavity or the mold temperature being too high, the plastic product may adhere to the mold. At this time, a large amount of gas may accumulate under the ejector pin. When the injection molded product is separated from the mold, the rapid release of the gas may cause the ejector pin to move upward too quickly, which is not conducive to the stable demolding of the injection molded product.

[0007] Based on the above ideas, the present invention provides the following technical solutions: a pneumatic demoulding device for a plastic mold, comprising a lower mold and a raised portion fixedly arranged on the top end surface of the lower mold, a top plate movably arranged at the top end surface of the lower mold, a push rod arranged below the top plate, a guide hole matching with the push rod is provided at the top end surface of the lower mold, an annular groove is provided at the inner wall of the guide hole, a notch is provided at the top end surface of the annular groove, and a positioning plate is provided at the notch, an annular plate is rotatably sleeved on the push rod, a sliding frame is connected to the outer peripheral surface of the annular plate, and the sliding frame is located on one side of the positioning plate; The top and bottom surfaces of the annular groove are both provided with upwardly protruding pressing parts, and an exhaust hole is opened on one side surface of the sliding frame close to the positioning plate. When the gas is discharged through the exhaust hole, the sliding frame can rotate along the annular groove, and the pressure of the pressing part on the sliding frame can drive the top rod and the top plate to move upward.

[0008] As a further solution of the present invention: a guide groove is provided on the top rod, the bottom end of the guide groove extends to the bottom end surface of the top rod, the top end of the guide groove extends to the outer peripheral surface of the top rod, and a safety valve is provided at the bottom end of the guide groove.

[0009] As a further solution of the present invention: a slot matching the sliding frame is opened at the top end surface of the annular groove, the sliding frame is located below the slot, a positioning strip is fixedly arranged on the inner bottom surface of the annular groove, the positioning strip is located below the notch and on the side of the positioning plate away from the sliding frame.

[0010] As a further solution of the present invention: a slider is fixedly provided on the bottom surface of the positioning plate, a sliding groove slidably matched with the slider is provided at the bottom surface of the annular groove, the slider is elastically arranged in the sliding groove, a limiting hole is provided at the bottom surface of the inner part of the sliding groove, and a limiting block matching with the limiting hole is provided at the bottom end surface of the slider, an inclined extrusion surface is provided on the top side of the positioning plate and the bottom side of the sliding frame, a magnetic strip is fixedly embedded on the extrusion surface on the sliding frame, and a magnetic plate is slidably provided on the extrusion surface of the positioning plate, when the sliding frame moves to the top side of the positioning plate, the magnetic plate and the magnetic strip can be aligned, and the opposite side of the magnetic plate and the magnetic strip have different magnetic poles, and a pull rope is fixedly provided between the magnetic plate and the limiting block.

[0011] As a further solution of the present invention: a straight groove and an oblique groove that are interconnected are provided on the circumferential surface of the inner cavity of the groove, an inclined surface is provided at the bottom end surface of the oblique groove, an inclined plate is elastically installed at the junction of the straight groove and the oblique groove, the inclined plate is hinged to the lower mold, when the inclined plate is in a state parallel to the oblique groove, the inclined plate can deflect relative to the lower mold toward the direction close to the oblique groove, and a guide column is elastically provided on the side of the sliding frame away from the top rod.

[0012] As a further solution of the present invention: a stopper is provided on one side of the slide frame away from the positioning plate, the stopper is elastically mounted on the inner bottom surface of the annular groove, and a side of the top of the stopper close to the slide frame is an inclined guide surface.

[0013] As a further solution of the present invention: a limit spring is fixedly arranged between the bottom surface of the inclined plate and the inner wall of the straight groove.

[0014] As a further solution of the present invention: the interior of the annular plate is a cavity structure, and the side of the annular plate that fits the push rod is an annular opening structure.

[0015] As a further solution of the present invention: the bottom end surface of the positioning plate contacts the bottom end surface of the annular groove, and the top end of the positioning plate is placed on the bottom side of the notch and contacts the top end surface of the annular groove.

[0016] As a further solution of the present invention: an air inlet hole connected to the guide hole is provided at the bottom end surface of the lower mold.

[0017] Compared with the prior art, the beneficial effect of the present invention is that the device cooperates with the sliding frame through the provided pressing portion, so that the sliding frame can drive the ejector rod and the ejector plate to move upward a short distance in the process of sliding along the annular groove, so that the molded product can be quickly and stably lifted from the protruding portion, and in the process of the ejector rod further lifting the top plate, the sliding frame can return to the side of the positioning plate and reset, so as to facilitate the continuous use of the device. Compared with the traditional pneumatic demolding method, this structure can still stably demold when the molded product is severely adhered to the protruding portion, and can maintain the integrity of the product to the maximum extent. The position of the molded product relative to the top plate will not change significantly. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0019] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 is a cross-sectional view of the present invention; Figure 3 The present invention Figure 2 A schematic diagram of the enlarged structure at B; Figure 4 The present invention Figure 2 A schematic diagram of the enlarged structure at point A; Figure 5 It is a schematic diagram of the guide hole and the annular groove structure of the present invention; Figure 6 It is a schematic diagram of the positioning plate and the sliding frame structure of the present invention; Figure 7 It is a schematic diagram of the structure of the slider and the limiting hole of the present invention; Figure 8 It is a schematic diagram of the structure of the magnetic strip and magnetic plate of the present invention; Fig. 9 It is a schematic diagram of the block structure of the present invention; Fig.10 It is a schematic diagram of the straight slot and the inclined slot structure of the present invention; Fig.11 It is a schematic structural diagram of the top pressing part of the present invention; Fig.12 It is a schematic diagram of the inclined plane structure of the present invention.

[0020] In the figure: 1. lower die; 101. air inlet; 102. guide hole; 103. annular groove; 104. slot; 105. notch; 106. straight groove; 107. inclined groove; 2. top plate; 3. ejector rod; 301. guide groove; 4. raised portion; 5. inclined surface; 6. annular plate; 7. stopper; 701. guide surface; 8. slide frame; 801. exhaust hole; 9. positioning plate; 10. positioning strip; 11. limit hole; 12. slide block; 13. magnetic strip; 14. magnetic plate; 15. pull rope; 16. limit block; 17. guide column; 18. inclined plate; 19. top pressure portion; 20. exhaust channel; 21. extrusion surface; 22. sealing block. DETAILED DESCRIPTION

[0021] like Figure 1 As shown, a pneumatic demoulding device for a plastic mold comprises a lower mold 1 and a raised portion 4 fixedly arranged on the top end surface of the lower mold 1, a top plate 2 is movably arranged at the top end surface of the lower mold 1, and a push rod 3 is arranged below the top plate 2. Specifically, the bottom end of the push rod 3 extends into the lower mold 1 and can move in the vertical direction relative to the lower mold 1. In actual use, the upper mold is driven to move downward and press on the push plate 2 by an external power mechanism, and the cooperation between the upper mold and the lower mold 1 is utilized to complete the molding of the plastic product. In the demoulding process, the push rod 3 can be lifted up by pneumatic means, and the push rod 3 is used to drive the push plate 2 to move upward. Since the injection molded product is located on the top plate 2, when the top plate 2 moves upward, the formed product can be lifted up from the raised portion 4, thereby completing the demoulding operation.

[0022] Reference Figure 1-Figure 2 , Figure 5-Figure 6As shown, the top end surface of the lower mold 1 is recessed downward to form a recessed portion matching the top plate 2, and a guide hole 102 matching the ejector rod 3 is opened at the recessed portion on the top end surface of the lower mold 1, and an air inlet hole 101 connected with the guide hole 102 is opened at the bottom end surface of the lower mold 1. In actual use, high-pressure gas is introduced into the guide hole 102 through the air inlet hole 101, and the pressure exerted on the ejector rod 3 by the guide hole 102 can drive the ejector rod 3 to move upward. Of course, in actual use, an air outlet hole connected with the guide hole 102 can be provided on the lower mold 1, and a solenoid valve can be installed in the air outlet hole to export the gas in the guide hole 102, so that the ejector rod 3 and the top plate 2 can move downward.

[0023] like Figure 2-Figure 6 As shown, in actual use, when the adhesion between a certain part of the injection molded product and the raised portion 4 is relatively strong, during the demoulding process, more gas will accumulate in the guide hole 102 below the ejector pin 3. When the product is separated from the raised portion 4, the ejector plate 2 will bounce upward at a relatively fast speed under the gas pressure, which is not conducive to the stable demoulding of the molded product. In order to solve this problem, the present invention provides an annular groove 103 on the inner wall of the guide hole 102. Figure 6 As shown, a notch 105 is provided at the top end surface of the annular groove 103, and a positioning plate 9 is provided at the notch 105, and an annular plate 6 is rotatably sleeved at the outer circumference of the ejector rod 3, and a sliding frame 8 is fixedly provided at the outer circumference of the annular plate 6, and the sliding frame 8 is connected with the annular plate 6, so that the gas passing through the ejector rod 3 can reach the sliding frame 8, and the sliding frame 8 is located on one side of the positioning plate 9, specifically, the bottom end surface of the positioning plate 9 is in contact with the bottom end surface of the annular groove 103, and the top end of the positioning plate 9 is placed on the bottom side of the notch 105 and in contact with the top end surface of the annular groove 103; For the convenience of description, the top end surface of the annular groove 103 is recorded as surface a, and the bottom end surface of the annular groove 103 is recorded as surface b. In actual use, a top pressing portion 19 that bulges upward is provided on both surface a and surface b of the annular groove 103. The top pressing portions 19 on surface a and surface b are parallel to each other. In actual use, an exhaust hole 801 is provided on one side surface of the slide frame 8 close to the positioning plate 9, so that the gas in the slide frame 8 can be discharged through the exhaust hole 801. When the molded product is severely bonded to the raised portion 4, the pressure on the ejector pin 3 will increase accordingly, so that the gas can be introduced into the slide frame 8 through the annular plate 6 and discharged through the exhaust hole 801. At this time, the pressure in the space formed by the positioning plate 9, the ejector rod 3, the slide frame 8 and the inner circumference of the annular groove 103 (for the convenience of description, this space is recorded as a sealed chamber) will gradually increase, thereby increasing the pressure on the slide frame 8 and enabling it to rotate along the annular groove 103. When the slide frame 8 rotates to the top pressing portion 19, the pressure of the top pressing portion 19 on the slide frame 8 can drive the ejector rod 3 to move upward for a distance, thereby driving the ejector plate 2 to move upward for a distance, so as to facilitate lifting the molded product from the raised portion 4. Since the raised height of the top pressing portion 19 is small, the ejector plate 2 can quickly and stably lift the molded product during the demolding process.

[0024] Reference Figure 2 As shown, a T-shaped guide groove 301 is provided on the push rod 3, the bottom end of the guide groove 301 extends to the bottom end surface of the push rod 3, and the top end of the guide groove 301 extends to the outer peripheral surface of the push rod 3. The interior of the annular plate 6 is a cavity structure, and the side of the annular plate 6 that is in contact with the push rod 3 is an annular opening structure. In actual use, a safety valve can be installed at the bottom end of the guide groove 301. When the pressure in the guide groove 301 below the push rod 3 reaches a threshold value, the safety valve can be opened to allow the gas to pass through the guide groove 301 and enter the annular plate 6.

[0025] Reference Figure 6-Figure 12 As shown, a slot 104 matching with the slide frame 8 is also provided at the top end surface of the annular groove 103. In the initial state, the slide frame 8 is located directly below the slot 104. A positioning bar 10 is fixedly provided at the inner bottom surface of the annular groove 103. The positioning bar 10 is located below the notch 105 and on the side of the positioning plate 9 away from the slide frame 8. When the slide frame 8 is driven by the force of air pressure to slide along the annular groove 103 to the positioning bar 10, the slide frame 8 stops rotating, and at this time, the slide frame 8 is below the notch 105. The bottom surface of the positioning plate 9 is fixedly provided with a slider 12, and the bottom surface of the annular groove 103 is provided with a slide groove that slidably cooperates with the slider 12. The slider 12 is elastically arranged in the slide groove, and a limiting hole 11 is provided on the bottom surface of the inner part of the slide groove, and a limiting block 16 that cooperates with the limiting hole 11 is provided on the bottom end surface of the slider 12. An inclined extrusion surface 21 is provided on the top side of the positioning plate 9 and the bottom side of the slide frame 8. A magnetic strip 13 is fixedly embedded on the extrusion surface 21 on the slide frame 8, and a magnetic plate 14 is slidably provided on the extrusion surface 21 of the positioning plate 9. When the slide frame 8 moves to the top side of the positioning plate 9, the magnetic plate 14 and the magnetic strip 13 can be aligned, and the opposite side of the magnetic plate 14 to the magnetic strip 13 has different magnetic poles. A pull rope 15 is fixedly provided between the magnetic plate 14 and the limiting block 16, and the pull rope 15 passes through the positioning plate 9 and the slider 12 and slidably cooperates with them; A straight groove 106 and an inclined groove 107 are provided on the inner surface of the notch 105. Fig.10 As shown, the top of the straight slot 106 is connected to the top of the oblique slot 107, and the bottom of the oblique slot 107 is offset toward the direction close to the slot 104. Fig.10 As shown, the bottom end of the inclined groove 107 is deflected downward to be in a vertical state, and a slope 5 is provided at the bottom end surface of the inclined groove 107. An inclined plate 18 is elastically installed at the junction of the straight groove 106 and the inclined groove 107. The inclined plate 18 is hinged to the lower mold 1. Specifically, the hinge position of the inclined plate 18 and the lower mold 1 is located between the top surface of the inclined plate 18 and the bottom surface of the inclined groove 107. Through this structure, when the inclined plate 18 is in a state parallel to the inclined groove 107, the inclined plate 18 can only deflect relative to the lower mold 1 in the direction close to the inclined groove 107, and a guide column 17 is elastically provided on the side of the slide frame 8 away from the top rod 3.

[0026] In actual use, when the molded product is in normal contact with the raised portion 4, in the process of injecting gas into the guide hole 102 through the air inlet 101, the pressure of the gas on the ejector pin 3 can drive the ejector pin 3 and the ejector plate 2 to move upward, thereby lifting the molded product from the raised portion 4. When the mold cavity is not smooth enough or the demoulding slope is unreasonable, the bonding force between the molded product and the raised portion 4 is large, as the air pressure in the guide hole 102 increases, the safety valve can be opened, so that the gas passes through the annular plate 6 to the slide frame 8 and is finally discharged through the exhaust hole 801. In this process, the air pressure in the sealed chamber will increase. Since in the initial state, the limiting The positioning block 16 is inserted into the limiting hole 11, so that the positioning plate 9 and the lower mold 1 are in a locked state, so that when the air pressure in the sealed chamber increases, the slide frame 8 can be pushed to slide along the annular groove 103, and through the provided pressing portion 19, when the slide frame 8 moves to the pressing portion 19, the pressure of the pressing portion 19 on the slide frame 8 can drive the ejector rod 3 to move upward for a distance, thereby driving the ejector plate 2 to move upward and lift the molded product, and when the slide frame 8 slides to the positioning strip 10, the slide frame 8 stops rotating. In this state, when the pressure in the guide hole 102 gradually increases, the ejector rod 3 and the ejector plate 2 can be driven to move upward, thereby further completing the demoulding operation; When the push rod 3 moves further upward, the slide frame 8 can move upward into the notch 105, and at this time, the side of the slide frame 8 with the exhaust hole 801 can contact the inner wall of the notch 105. When the guide column 17 is aligned with the straight groove 106, the guide column 17 can pop out and insert into the straight groove 106. As the push rod 3 moves upward, the guide column 17 will pass over the inclined plate 18 and move to the intersection of the straight groove 106 and the inclined groove 107. When the demoulding is completed and the guide hole 106 is released, 2, the top plate 2 and the top rod 3 will move downward under the action of gravity, so that the sliding frame 8 outside the top rod 3 can move downward. In this process, the guide column 17 on one side of the sliding frame 8 will slide along the inclined plate 18 into the inclined groove 107. The pressure of the inclined groove 107 on the guide column 17 can drive the sliding frame 8 to deflect in the direction close to the slot 104, so that the sliding frame 8 can move to the side of the positioning plate 9 close to the slot 104. As the top rod 3 continues to move downward, the sliding frame 8 The frame 8 will fall to the side of the positioning plate 9 and the extrusion surface 21 on the sliding frame 8 will fit with the extrusion surface 21 on the positioning plate 9. At the same time, the guide column 17 will also move to the inclined surface 5. The pressure of the inclined surface 5 on the guide column 17 enables the guide column 17 to retract into the sliding frame 8. When the sliding frame 8 is located on the side of the positioning plate 9, the suction force between the magnetic strip 13 and the magnetic plate 14 can pull the pull rope 15, so that the bottom end of the limit block 16 moves out of the limit hole 11 through the pulling force of the pull rope 15 on the limit block 16. At this point, the positioning plate 9 releases the locking relationship with the lower mold 1, so that the sliding frame 8 moves downward with the push rod 3. The interaction force between the sliding frame 8 and the extrusion surface 21 on the positioning plate 9 can push the positioning plate 9 in the direction away from the slot 104. When the sliding frame 8 completely falls to the bottom surface of the annular groove 103, the sliding frame 8 is no longer limited by the side wall of the notch 105, so the positioning plate 9 can push the sliding frame 8 to move back to the bottom of the slot 104 and reset it for the next use.

[0027] In summary, this device cooperates with the sliding frame 8 through the provided pressing portion 19, so that the sliding frame 8 can drive the ejector rod 3 and the top plate 2 to move upward a short distance during the sliding process along the annular groove 103, so that the molded product can be quickly and stably lifted from the protruding portion 4. In the process of the ejector rod 3 further lifting the top plate 2, the sliding frame 8 can return to the side of the positioning plate 9 and reset to facilitate the continuous use of the device. Compared with the traditional pneumatic demolding method, this structure can still stably demold when the molded product is severely adhered to the protruding portion 4, and can maintain the integrity of the product to the maximum extent. The position of the molded product relative to the top plate 2 will not change significantly.

[0028] Reference Figure 6 , Fig. 9As shown, a stopper 7 is provided on the side of the sliding frame 8 away from the positioning plate 9, and a groove slidably matched with the stopper 7 is opened at the inner bottom surface of the annular groove 103, and a spring is fixedly arranged between the inner end surface of the groove and the stopper 7, and the side of the top of the stopper 7 close to the sliding frame 8 is an inclined guide surface 701. In actual use, when the push rod 3 moves downward to drive the sliding frame 8 to be located on the side of the positioning plate 9 close to the slot 104, the positioning plate 9 can push the sliding frame 8 to reset, and when the sliding frame 8 moves to the stopper 7, it stops moving. At this time, the sliding frame 8 is located directly below the slot 104. Later, when the pressure between the sliding frame 8 and the guide surface 701 increases, the stopper 7 can be compressed into the groove.

[0029] Reference Figure 2 As shown, an exhaust channel 20 is opened on the inner bottom surface of the annular groove 103, the top end of the exhaust channel 20 is connected with the annular groove 103, and the bottom end of the exhaust channel 20 extends to the bottom end surface of the lower mold 1, and the exhaust channel 20 is located on the side of the positioning plate 9 away from the slot 104. In actual use, when the gas is discharged through the exhaust hole 801 to drive the slide frame 8 to move, the gas between the slide frame 8 and the positioning plate 9 can be discharged through the exhaust channel 20.

[0030] Reference Figure 3 As shown, a through groove is provided on the surface of the annular plate 6 opposite to the sliding frame 8 so as to facilitate the connection between the sliding frame 8 and the annular plate 6 .

[0031] An annular receiving groove is provided on the outer peripheral surface of the push rod 3 , and the annular plate 6 is rotatably disposed in the receiving groove. Specifically, the annular plate 6 can be matched with the push rod 3 via a sealed bearing.

[0032] Reference Figure 4 As shown, in addition to installing a safety valve at the bottom of the guide groove 301, a sealing block 22 can be elastically installed at the bottom of the guide groove 301. The sealing block 22 can move in the vertical direction relative to the guide groove 301. A baffle is provided below the sealing block 22. A through hole is opened at the center of the baffle. The through hole can be sealed by the sealing block 22. This structure can also play the role of a safety valve.

[0033] Reference Figure 7 As shown, an arc rod is fixedly arranged in the slide groove, the arc rod passes through the slider 12 and slides with it, and a first spring is sleeved on the outer side of the arc rod, the first spring is located on the side of the slider 12 away from the slide frame 8, and the first spring is between the slider 12 and the inner end face of the slide groove.

[0034] The extrusion surface 21 of the positioning plate 9 is provided with a mounting groove that slidably cooperates with the magnetic plate 14 , and the bottom surface of the positioning plate 9 is provided with a blind hole that slidably cooperates with the limit block 16 , and a second spring is fixedly arranged between the inner end surface of the blind hole and the limit block 16 .

[0035] Reference Fig.10 As shown, a limit spring is fixedly arranged between the bottom surface of the inclined plate 18 and the inner wall of the straight groove 106. The limit spring exerts a pulling force on the inclined plate 18 so that the bottom end of the inclined plate 18 abuts against the side wall of the straight groove 106 without rotating.

Claims

1. A pneumatic demoulding device for a plastic mold, comprising a lower mold and a raised portion fixedly arranged on the top end surface of the lower mold, a top plate movably arranged at the top end surface of the lower mold, a push rod arranged below the top plate, a guide hole cooperating with the push rod opened at the top end surface of the lower mold, characterized in that: An annular groove is provided on the inner wall of the guide hole, a notch is provided on the top end surface of the annular groove, and a positioning plate is provided at the notch, an annular plate is rotatably sleeved on the top rod, and a sliding frame is connected to the outer peripheral surface of the annular plate, and the sliding frame is located on one side of the positioning plate; The top and bottom surfaces of the annular groove are both provided with upwardly protruding pressing parts, and an exhaust hole is opened on one side surface of the sliding frame close to the positioning plate. When the gas is discharged through the exhaust hole, the sliding frame can rotate along the annular groove, and the pressure of the pressing part on the sliding frame can drive the top rod and the top plate to move upward.

2. A pneumatic demoulding device for a plastic mold according to claim 1, characterized in that: The top rod is provided with a guide groove, the bottom end of the guide groove extends to the bottom end surface of the top rod, the top end of the guide groove extends to the outer peripheral surface of the top rod, and a safety valve is provided at the bottom end of the guide groove.

3. A pneumatic demoulding device for a plastic mold according to claim 2, characterized in that: A slot matching the slide frame is provided at the top end surface of the annular groove, and the slide frame is located below the slot. A positioning strip is fixedly provided at the inner bottom surface of the annular groove, and the positioning strip is located below the notch and on the side of the positioning plate away from the slide frame.

4. A pneumatic demoulding device for a plastic mold according to claim 3, characterized in that: A slider is fixedly provided on the bottom surface of the positioning plate, a sliding groove that slidably cooperates with the slider is provided on the bottom surface of the annular groove, the slider is elastically arranged in the sliding groove, a limiting hole is provided on the bottom surface of the inner part of the sliding groove, and a limiting block that cooperates with the limiting hole is provided on the bottom end surface of the slider. Inclined extrusion surfaces are provided on the top side of the positioning plate and the bottom side of the sliding frame, a magnetic strip is fixedly embedded on the extrusion surface of the sliding frame, and a magnetic plate is slidably provided on the extrusion surface of the positioning plate. When the sliding frame moves to the top side of the positioning plate, the magnetic plate and the magnetic strip can be aligned, and the opposite side of the magnetic plate and the magnetic strip has different magnetic poles, and a pull rope is fixedly provided between the magnetic plate and the limiting block.

5. A pneumatic demoulding device for a plastic mold according to claim 4, characterized in that: A straight groove and an oblique groove that are interconnected are provided on the circumferential surface of the inner cavity of the slot, an inclined surface is provided on the bottom end surface of the oblique groove, an inclined plate is elastically installed at the junction of the straight groove and the oblique groove, the inclined plate is hinged to the lower mold, when the inclined plate is in a state parallel to the oblique groove, the inclined plate can deflect relative to the lower mold toward the direction close to the oblique groove, and a guide column is elastically provided on the side of the sliding frame away from the push rod.

6. A pneumatic demoulding device for a plastic mold according to claim 1, characterized in that: A stopper is arranged on one side of the slide frame away from the positioning plate. The stopper is elastically mounted on the inner bottom surface of the annular groove, and a side of the top of the stopper close to the slide frame is an inclined guide surface.

7. A pneumatic demoulding device for a plastic mold according to claim 5, characterized in that: A limit spring is fixedly arranged between the bottom surface of the inclined plate and the inner wall of the straight groove.

8. The pneumatic demoulding device for plastic mold according to claim 1, characterized in that: The interior of the annular plate is a cavity structure, and the side of the annular plate that fits the push rod is an annular opening structure.

9. The pneumatic demoulding device for plastic mold according to claim 1, characterized in that: The bottom end surface of the positioning plate contacts the bottom end surface of the annular groove, and the top end of the positioning plate is placed on one side of the bottom of the notch and contacts the top end surface of the annular groove.

10. The pneumatic demoulding device for plastic mold according to claim 1, characterized in that: An air inlet hole connected with the guide hole is provided at the bottom end surface of the lower mold.

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