A vacuum stretching device for a plastic vertical foaming furnace

Abstract

The present invention discloses a vacuum stretching device for a plastic vertical foaming furnace, which comprises two vacuum clamping mechanisms symmetrically arranged on both sides of a foamed sheet; the vacuum clamping mechanism comprises a bottom plate, a front suction plate and a rear suction plate which are installed on the bottom plate and arranged oppositely, and a holding gap for the foamed sheet to pass through is arranged between the front suction plate and the rear suction plate; a group of suction holes are uniformly distributed on the opposite surfaces of the front suction plate and the rear suction plate, and the other ends of the suction holes are connected with a vacuum pumping device. By means of the front suction plate and the rear suction plate, the foamed sheet is kept in the holding gap and maintained in a semi-adsorbed state, so as to ensure the stability of the stretching operation of the foamed sheet, reduce the maintenance cost, and can be widely applied to the field of vacuum stretching devices for plastic vertical foamed sheets.

Description

Technical Field

[0001] The present invention relates to the technical field of plastic foam processing, and in particular to a vacuum stretching device for a plastic vertical foam furnace. Background Art

[0002] In the processing of plastic foam products, the plastic raw material in a molten state is foamed in a plastic vertical foam furnace. During the foaming process, expansion occurs in terms of thickness and width. At this time, the raw material is in a semi-molten state. If it is not unfolded in time, the sheets will overlap and stick to each other, affecting the quality of the finished product. Therefore, it is necessary to use a vacuum stretching device to unfold it in time. The current vacuum stretching device stretches the sheet to both sides through a mechanical vacuum clamping mechanism, but there is a problem that the foamed sheet sticks to the vacuum stretching device, which requires regular cleaning, resulting in cumbersome later maintenance and affecting the surface quality of the sheet. For example, Chinese Patent Application No. 2015209586032 discloses a vacuum stretching device for a plastic vertical foam furnace, especially a vacuum stretching device for crosslinked polyolefin foam plastics vertically. It includes a first stretching roller and a second stretching roller. An outer sleeve one is arranged outside the first stretching roller, and an outer sleeve two is arranged outside the second stretching roller. The outer sleeve two is connected to the bottom plate through a first mounting seat and a second mounting seat. A first transmission gear is arranged on the outer sleeve one, and a second transmission gear is arranged on the outer sleeve two. The first transmission gear and the second transmission gear cooperate with each other. This structure needs to wait for 10 minutes for replacement every 48 hours. Although it has been improved compared with the previous ones, it still affects the production efficiency.

[0003] At the same time, in the existing stretching device structure, the angle adjustment is not convenient, and for sheets of different thicknesses, corresponding replacement and adjustment are required, with poor versatility and unable to simultaneously meet the stretching of sheets of different widths and thicknesses. Summary of the Invention

[0004] The purpose of the present invention is to provide a vacuum stretching device for a plastic vertical foam furnace, which solves the problems that the existing stretching device will contact the sheet, has unstable operation, and is inconvenient for maintenance and use.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a vacuum stretching device for plastics vertically includes two vacuum clamping mechanisms symmetrically arranged on both sides of the foamed sheet; the vacuum clamping mechanism includes a bottom plate, a front suction plate and a rear suction plate which are installed on the bottom plate and arranged opposite to each other. A holding gap for the foamed sheet to pass through is arranged between the front suction plate and the rear suction plate; a group of suction holes are evenly distributed on the opposite surfaces of the front suction plate and the rear suction plate, and the other ends of the suction holes are connected with a vacuum pumping device.

[0006] To ensure that the suction holes can provide an upward pulling force to the foamed sheet, ensure that the foamed sheet has a certain tension and is conveyed downward, the suction holes are of an inclined hole structure arranged obliquely upward.

[0007] To ensure the clamping stability of the vacuum clamping mechanism and avoid the interference of external air flow on the clamping effect, an air suction chamber is connected and arranged at the rear end of the holding gap, and the air suction chamber is connected to a vacuum pumping device.

[0008] To prevent the side bulge of the foamed sheet from getting stuck in the holding gap and affecting the propulsion speed, an auxiliary perforated belt that moves along the conveying direction of the foamed sheet is arranged inside the holding gap.

[0009] To facilitate the adjustment of the positions of the front air suction plate and the rear air suction plate, an upper slide rail is arranged at the top of the bottom plate, and a lower slide rail is arranged at the bottom. Upper guide rails adapted to the upper slide rail are arranged at the top of the front air suction plate and the rear air suction plate, and lower guide rails adapted to the lower slide rail are arranged at the bottom.

[0010] Furthermore, a gap adjustment structure for adjusting the width of the holding gap is arranged between the front air suction plate and the rear air suction plate. The gap adjustment structure includes an adjustment rod, on which a forward thread section and a reverse thread section are arranged. A forward threaded hole adapted to the forward thread section is arranged on the front air suction plate, and a reverse threaded hole adapted to the reverse thread section is arranged on the rear air suction plate.

[0011] To ensure the running stability of the auxiliary belt, a first vertical plate is also arranged. A group of guide wheels are rotatably installed on the first vertical plate, and the auxiliary belt is wound around the guide wheels. One of the guide wheels is connected to a guide wheel drive motor; the bottom plate is fixedly installed on the first vertical plate.

[0012] To facilitate the adjustment of the inclination angle of the holding gap, the first vertical plate is connected to a rotating shaft that drives the first vertical plate to rotate, and the other end of the rotating shaft is connected to a rotating shaft drive motor.

[0013] To facilitate the adjustment of the distance between the two vacuum clamping mechanisms, it further includes a frame, a driving lead screw installed on the frame, and a slide table that moves back and forth along the driving lead screw. The guide wheel drive motor and the rotating shaft drive motor are fixedly installed on the slide table.

[0014] A position sensor for detecting the edge position of the foamed sheet is arranged above the vacuum clamping mechanism, and a PLC controller is also arranged. The PLC controller receives the signal of the position sensor and controls the rotation of the driving lead screw. The edge position of the foamed sheet is detected in real time through the position sensor, and then the slide table is driven to move back and forth through the driving lead screw, so as to ensure that the edge of the foamed sheet is always within the holding gap, so as to maintain the clamping force of the vacuum clamping mechanism on the foamed sheet.

[0015] Advantages of the present invention: By the simultaneous suction of the front suction plate and the rear suction plate acting on the front and back surfaces of the foamed sheet, the foamed sheet is maintained in a semi-adsorbed state. Compared with other stretching devices, this structure will not cause the foamed sheet to adhere to the vacuum stretching device, solving the problem of sheet breakage caused by the adhesion of the foamed sheet to the vacuum stretching device. At the same time, it also eliminates the trouble of regular maintenance and cleaning, improves the operation stability and reliability of the equipment, and also ensures the surface quality of the foamed sheet, avoiding the problem of irregular wrinkles on the surface of the foamed sheet caused by the contact and pulling between the foamed sheet and the vacuum stretching device. Due to the existence of the suction chamber, when the foamed sheet enters the stretching device, under the action of the vacuum device, a certain three-sided negative pressure will be formed in the holding gap, thereby ensuring the adsorption and clamping effect on the foamed sheet. At the same time, since the suction holes are upward inclined hole structures, an upward inclined suction force can be provided to the foamed sheet. Cooperating with the cooling roller below the stretching device, the cooling roller provides a downward pulling force to drive the sheet forward, so that the foamed sheet always maintains a certain tension and is conveyed downward, thereby improving the stretching effect of the foamed sheet and avoiding wrinkles. When the auxiliary belt contacts the side of the foamed sheet, it can apply a certain downward conveying force to the foamed sheet, avoiding the problem that the local protrusion of the side of the foamed sheet contacts and jams with the bottom plate, affecting the conveying progress. The first vertical plate is driven to rotate by a rotating shaft, which is used to adjust the inclination angle of the holding gap, thereby adjusting the opening angle of the two vacuum clamping mechanisms to meet the requirements of different foamed sheets, and the adjustment is simple and convenient. The vacuum clamping mechanism is integrally installed on the driving lead screw and can move back and forth, thereby adjusting the distance between the two vacuum clamping mechanisms to meet the processing requirements of foamed sheets with different widths, and the adjustment accuracy is high and the adjustment is convenient. At the same time, by cooperating the position sensor with the driving lead screw, the position of the sliding table is adjusted in real time to ensure that the edge of the foamed sheet is always within the holding gap, so as to maintain the clamping force of the vacuum clamping mechanism on the foamed sheet.

[0016] The present invention will be described in more detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a three-dimensional structural schematic diagram of the present invention.

[0018] Figure 2 is a three-dimensional structural schematic diagram of the unilateral structure in the present invention.

[0019] Figure 3 is an exploded view of the support assembly and the vacuum clamping mechanism installed on the support assembly in the present invention.

[0020] Figure 4 is a cross-sectional view of the rear suction plate in the present invention.

[0021] Figure 5 is a structural schematic diagram of the gap adjustment structure in the present invention. Detailed implementation manners

[0022] Examples are as follows Figures 1 to 5 As shown, a vacuum stretching device for a plastic vertical foaming furnace includes a frame 16. Two driving lead screws 17 are symmetrically arranged on the frame 16. Vacuum clamping mechanisms are respectively installed on the driving lead screws 17 for clamping both sides of the foamed sheet material.

[0023] Four lead screw fixing seats 19 are fixedly installed on the frame 16. Both ends of the driving lead screw 17 are rotatably installed on the lead screw fixing seats 19 through support bearings. A slide table 18 that moves back and forth along the driving lead screw is arranged on the driving lead screw 17. A lead screw nut is fixedly arranged on the slide table 18, and the lead screw nut cooperates with the driving lead screw 17 to drive the slide table 18 to move back and forth. One end of the driving lead screw 17 is connected with a lead screw driving motor 20 that drives the driving lead screw 17 to rotate. Two guide rails 23 are also arranged on the lead screw fixing seats 19. A guide sleeve adapted to the guide rails 23 is arranged below the slide table 18 to ensure the running accuracy of the slide table 18. A PLC controller 29 is also provided, which is used to control the operation of the lead screw driving motor 20, drive the driving lead screw 17 to rotate, and make the slide table 18 move back and forth.

[0024] A guide wheel driving motor 13, a rotating shaft driving motor 15 and a reducer matching the driving motors are fixedly installed on the slide table 18. The output end of the rotating shaft driving motor 15 is connected with a rotating shaft 14, and a support assembly is fixedly installed at the other end of the rotating shaft 14. The rotation of the rotating shaft 14 drives the support assembly to rotate. The support assembly includes a first vertical plate 11, a second vertical plate 24 and a support plate 25 arranged between the first vertical plate 11 and the second vertical plate 24. The first vertical plate 11, the second vertical plate 24 and the support plate 25 are fixedly connected by bolts. The rotating shaft 14 is fixedly connected with the first vertical plate 11, and the rotation of the rotating shaft drives the entire support assembly to rotate.

[0025] One side of the support component is fixedly installed with a bottom plate 1. The first vertical plate 11, the second vertical plate 24 and the support plate 25 form a suction chamber 27 at the rear end of the bottom plate 1. A suction hole 111 communicating with the suction chamber 27 is provided on the first vertical plate 11. The suction hole 111 is connected to a vacuum pumping device 5 to pump the suction chamber 27 to a vacuum. The bottoms 1 of the two vacuum clamping mechanisms are arranged oppositely. A front suction plate 2 and a rear suction plate 3 are installed on the bottom plate 1. The front suction plate 2 and the rear suction plate 3 are arranged oppositely. A holding gap 6 for the foamed sheet to pass through is provided between the front suction plate 2 and the rear suction plate 3. The holding gap 6 communicates with the suction chamber 27. A group of suction holes 4 are evenly distributed on the opposite surfaces of the front suction plate 2 and the rear suction plate 3. The other ends of the suction holes 4 are connected with a vacuum pumping device 5. The vacuum pumping device 5 can adopt a common vacuum pump structure, and no examples will be given one by one here. A main air duct 26 is arranged in the front suction plate 2 and the rear suction plate 3. One end of the main air duct 26 is connected to the vacuum pumping device 5. The suction holes 4 communicate with the main air duct 26. The suction holes 4 are inclined hole structures arranged obliquely upward, and the inclination angle is 45-55°. That is, the end of the suction hole 4 located on the surface of the front suction plate 2 or the rear suction plate 3 is at a lower position, and the end connected to the main air duct 26 is at a higher position. By pumping air through the vacuum device 5, the holding gap 6 is in a negative pressure state, and the vacuum pumping forces of the front suction plate 2 and the rear suction plate 3 are kept in a certain balance. At the same time, under the action of the inclined holes of the suction holes 4, the foamed sheet passing through the holding gap 6 always has an upward and lateral pulling force. A cooling roller for driving the foamed sheet to move forward is arranged below the spreader. The cooling roller gives the foamed sheet a downward force, and the front suction plate and the rear suction holes provide an upward force to the foamed sheet. Of course, the upward force is less than the downward force provided by the cooling roller, so that the foamed sheet can maintain a certain tension and be conveyed downward under the action of the cooling roller and the spreader.

[0026] To facilitate the adjustment of the distance between the front suction plate 2 and the rear suction plate 3, that is, to adjust the width of the holding gap 6 to meet the clamping of foamed sheets of different thicknesses, an upper slide rail 101 is provided at the top of the bottom plate 1, and a lower slide rail 102 is provided at the bottom. Upper guide rails 8 adapted to the upper slide rail 101 are provided at the tops of the front suction plate 2 and the rear suction plate 3, and lower guide rails 9 adapted to the lower slide rail 102 are provided at the bottoms. This structure enables the front suction plate 2 and the rear suction plate 3 to move back and forth on the bottom plate 1. For convenient adjustment, a gap adjustment structure 10 for adjusting the width of the holding gap 6 is provided between the front suction plate 2 and the rear suction plate 3. The gap adjustment structure 10 includes an adjustment rod 1001. A forward thread section 1002 and a reverse thread section 1003 are provided on the adjustment rod 1001. A forward threaded hole (not marked in the figure) adapted to the forward thread section 1002 is provided on the front suction plate 2, and a reverse threaded hole 31 adapted to the reverse thread section 1003 is provided on the rear suction plate 3. By rotating the adjustment rod 1001, the front suction plate 2 and the rear suction plate 3 can be driven to move towards each other and in opposite directions simultaneously. Of course, the front suction plate 2 and the rear suction plate 3 can also be adjusted to move separately by two threaded rods.

[0027] To prevent the side end of the foamed sheet from being severely deformed and contacting the bottom plate at the bottom of the holding gap 6, resulting in adhesion or tearing and affecting the running speed of the foamed sheet, an auxiliary belt 7 moving along the conveying direction of the foamed sheet is provided inside the holding gap 6. When the foamed sheet contacts the auxiliary belt 7, the auxiliary belt 7 drives the foamed sheet to move downward to ensure normal operation.

[0028] The specific installation structure of the auxiliary belt 7 is as follows: A set of guide wheels 12 are rotatably installed on the support assembly, and the auxiliary belt 7 is wound around the guide wheels 12. The support shafts of the guide wheels 12 are respectively supported on the first vertical plate 11 and the second vertical plate 24. The support plate 25 is provided with a relief groove at the position of the guide wheels 12. One of the guide wheels 12 is connected to a guide wheel drive motor 13, and the guide wheel drive motor 13 drives the auxiliary belt 7 to rotate.

[0029] In order to be able to maintain a clamping force on the foamed sheet in real time and prevent the foamed sheet from detaching from the holding gap or seriously exceeding the depth of the holding gap due to changes in the edge dimensions of the foamed sheet, a position sensor 28 for detecting the edge position of the foamed sheet is provided above the vacuum clamping mechanism. The PLC controller 29 receives the signal from the position sensor 28 and controls the operation of the lead screw drive motor 20 to drive the lead screw 17 to rotate, causing the slide table 18 to move back and forth to adjust the position of the clamping mechanism, ensuring that the foamed sheet is always in the holding gap 6 and ensuring the stable operation of the foamed sheet. Two position sensors 28 are arranged side by side. When the edge of the foamed sheet is not between the two position sensors 28, the lead screw drive motor 20 operates to ensure that the edge of the foam is always in the area between the two position sensors 28.

[0030] In the present invention, the slide table moves back and forth on the lead screw, so that the distance between the two vacuum clamping mechanisms can be conveniently adjusted to meet the processing requirements of foamed sheets with different widths. At the same time, the support assembly can be rotated by the rotating shaft to adjust the inclination angle of the holding gap to meet the requirements of the foaming speeds of different foamed sheets. For different foamed sheets, the speed of expanding to both sides is different, some are fast and some are slow. In addition, through the action of the vacuum pumping device, the foamed sheet is in a semi-adsorbed state, that is, it has a certain adsorption force and is not completely adsorbed and stuck, avoiding the adhesion of the foamed sheet and affecting the quality of the sheet, and there is no need for regular cleaning, so the stability of the equipment is better. It can also monitor the position of the edge of the foamed sheet in real time through the position sensor and make real-time adjustments to ensure that the vacuum clamping mechanism always acts on the foamed sheet during the transportation of the foamed sheet, ensuring the stability of the operation of the foamed sheet.

[0031] The present invention has been described exemplarily in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above methods. As long as various non-substantive improvements are made by adopting the method concept and technical solution of the present invention; or without improvement, the above concept and technical solution of the present invention are directly applied to other occasions, they are all within the protection scope of the present invention.

Claims

1. A vacuum stretching device for a plastic vertical foaming furnace, characterized in that: It includes two vacuum clamping mechanisms symmetrically arranged on both sides of the foaming sheet; the vacuum clamping mechanism includes a bottom plate (1), a front suction plate (2) and a rear suction plate (3) which are installed on the bottom plate (1) and arranged oppositely, and a holding gap (6) for the foaming sheet to pass through is arranged between the front suction plate (2) and the rear suction plate (3); a group of suction holes (4) are evenly distributed on the opposite surfaces of the front suction plate (2) and the rear suction plate (3), and the other ends of the suction holes (4) are connected with a vacuum pumping device (5). The suction holes (4) are of an inclined hole structure arranged obliquely upward, and a cooling roller for driving the foaming sheet to move forward is arranged below the vacuum expander. An auxiliary belt (7) moving along the conveying direction of the foaming sheet is arranged inside the holding gap (6), and an air suction chamber (27) is connected and arranged at the rear end of the holding gap (6), and the air suction chamber (27) is connected with the vacuum pumping device (5).

2. The vacuum stretching device for the plastic vertical foaming furnace according to claim 1, characterized in that: An upper slide rail (101) is arranged at the top of the bottom plate (1), and a lower slide rail (102) is arranged at the bottom. Upper guide rails (8) adapted to the upper slide rail (101) are arranged at the tops of the front suction plate (2) and the rear suction plate (3), and lower guide rails (9) adapted to the lower slide rail (102) are arranged at the bottoms.

3. The vacuum stretching device for a plastic vertical foaming furnace according to claim 1, characterized in that: A gap adjusting structure (10) for adjusting the width of the holding gap (6) is arranged between the front suction plate (2) and the rear suction plate (3). The gap adjusting structure (10) includes an adjusting rod (1001). A forward thread section (1002) and a reverse thread section (1003) are arranged on the adjusting rod (1001). A forward threaded hole adapted to the forward thread section (1002) is arranged on the front suction plate (2), and a reverse threaded hole (31) adapted to the reverse thread section (1003) is arranged on the rear suction plate (3).

4. The vacuum stretching device for a plastic vertical foaming furnace according to claim 1, characterized in that: A first vertical plate (11) is also arranged. A group of guide wheels (12) are rotatably installed on the first vertical plate (11). The auxiliary belt (7) is wound around the guide wheels (12), and one of the guide wheels (12) is connected with a guide wheel driving motor (13); the bottom plate (1) is fixedly installed on the first vertical plate (11).

5. The vacuum stretching device for the plastic vertical foaming furnace according to claim 4, characterized in that: The first vertical plate (11) is connected with a rotating shaft (14) for driving the first vertical plate (11) to rotate, and the other end of the rotating shaft (14) is connected with a rotating shaft driving motor (15).

6. The vacuum stretching device for a plastic vertical foaming furnace according to claim 4, characterized in that: It also includes a frame (16), a driving lead screw (17) installed on the frame (16), and a slide table (18) moving back and forth along the driving lead screw on the driving lead screw (17). The guide wheel driving motor (13) and the rotating shaft driving motor (15) are fixedly installed on the slide table (18).

7. The vacuum stretching device for the plastic vertical foaming furnace according to claim 6, characterized in that: A position sensor (28) for detecting the edge position of the foaming sheet is arranged above the vacuum clamping mechanism, and a PLC controller (29) is also arranged. The PLC controller (29) receives the signal of the position sensor (28) and controls the rotation of the driving lead screw (17).

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