Three-section type center counter-pressing pre-pressing forming machine and using method thereof

Abstract

The invention discloses a three-section type center opposite-pressing pre-pressing forming machine and a using method thereof. The three-section type center opposite-pressing pre-pressing forming machine comprises a rack, a top plate arranged on the rack, a discharging hopper arranged on the top plate and a lower pushing oil cylinder with an upper pressing head, a hole plate arranged on the rack, an upper sliding plate arranged on the hole plate in a left-right sliding mode, and a feeding barrel arranged on the upper sliding plate. A bottom plate is arranged on the machine frame, an upper jacking oil cylinder, a material jacking air cylinder and a lower sliding plate capable of sliding left and right are arranged on the bottom plate, a discharging barrel and a heightening frame are fixedly arranged on the lower sliding plate, a lower pressing head is movably arranged in the discharging barrel in a sealed mode, a hinge seat is hinged to the heightening frame, and a liftable supporting plate is arranged on the hinge seat. A detachable middle charging barrel is arranged on the supporting plate, needle holes are formed in the side wall of the upper charging barrel, the side wall of the middle charging barrel and the side wall of the lower charging barrel, and a feeding mechanism is arranged on the machine frame. According to the invention, the compactness and the working efficiency of plastic can be improved.

Description

Technical Field

[0001] The invention relates to the field of plastic molding equipment, and in particular to a three-stage center-pressing pre-pressing molding machine and a use method thereof. Background Art

[0002] When using a plunger extruder for extrusion, the plastic needs to be pushed forward by the reciprocating motion of the plunger, because the plunger works intermittently, and each movement pushes a certain amount of plastic. If the plastic itself is not dense enough or contains air, it may cause unstable pressure during the extrusion process and defects in the product, such as pores or rough surface. This requires pre-pressing the loose plastic to expel the air in the plastic and increase the density of the plastic. At present, traditional pre-pressing equipment generally uses a cylinder to squeeze the loose plastic downward. During unidirectional extrusion, the plastic is only compressed from one direction and is affected by the friction of the barrel wall, causing the pressure to gradually decay along the transmission direction. The area far away from the pressure source may reduce the density due to insufficient pressure, forming a density gradient. At the same time, the bubbles or gaps in the plastic may be pushed to the end during unidirectional extrusion and are difficult to be completely discharged, forming defects. In addition, when taking and discharging materials, the compacted plastic needs to be taken out before the loose plastic can be put back in for pre-pressing, which reduces work efficiency. Summary of the invention

[0003] The object of the present invention is to provide a three-stage center-pressure pre-pressing forming machine and a method of using the same, which can improve the pre-pressing effect and facilitate the taking and placing of materials.

[0004] To achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: a three-stage center-to-center pressure pre-pressing forming machine, comprising: a frame, a top plate is arranged on the top of the frame, a liftable discharge hopper and a push-down cylinder are arranged on the top plate, an upper pressure head is arranged on the push-down cylinder, a liftable orifice plate is arranged on the frame below the top plate, an upper slide plate is arranged on the orifice plate for sliding left and right, a loading barrel passing through the orifice plate is fixedly arranged on the upper slide plate, a left upper limit seat is arranged on the left side of the orifice plate, when the upper slide plate abuts against the left upper limit seat, the loading barrel is coaxially aligned with the upper pressure head, two counterweights are symmetrically arranged front and back on the left side wall of the upper slide, a bottom plate is arranged at the bottom of the frame, an upper top cylinder and a lower slide plate which can slide left and right are arranged on the bottom plate, a through hole is arranged on the lower slide plate, a lower barrel and a heightening frame are fixedly arranged on the lower slide plate, a left lower limit seat and a right lower limit seat are respectively arranged on the left and right sides of the bottom plate, the left lower limit seat is aligned up and down with the left upper limit seat, when When the lower slide plate abuts against the lower right limit seat, the lower material barrel is coaxially aligned with the discharge hopper, a lower pressure head is provided in the lower material barrel for movable sealing, a material ejecting cylinder is provided on the bottom plate, a strong magnetic block is provided on the piston rod of the material ejecting cylinder, an articulated seat is hinged on the elevated frame, a lifting cylinder is provided on the articulated seat, the piston rod of the lifting cylinder is connected to the support plate, two rows of linear bearings are provided on the support plate, a guide rod is slidably provided in the linear bearing on the same side, the guide rod is fixed in the articulated seat, and the guide rod is fixed on the support plate. A detachable middle barrel is provided on the upper part, a turning cylinder is hinged on the elevated frame, a connecting plate is provided between the two guide rods, the piston rod of the turning cylinder is hinged to the connecting plate, vertical limit seats are provided at the front and rear ends of the elevated frame, pinholes are provided on the side walls of the upper barrel, the middle barrel and the lower barrel, the bottom end of the upper barrel can be connected with the top end of the middle barrel, the bottom end of the middle barrel can be connected with the top end of the lower barrel, and a feeding mechanism capable of feeding materials into the discharge hopper is provided on the frame.

[0005] Furthermore, the aforementioned three-stage center-pressure pre-pressing forming machine, wherein the feeding mechanism includes: a connection structure between the feeding hopper and the frame: a fixed plate arranged at the rear side of the frame, two guide rail seats and a double-axis reduction motor are vertically arranged on the fixed plate, a driving gear is connected to the two output shafts of the double-axis reduction motor, a rotating shaft is rotatably arranged between the tops of the two guide rail seats, a driven gear is arranged at both ends of the rotating shaft, a transmission chain is connected between the driving gear and the driven gear on the same side, a chain connecting pin is arranged on the transmission chains on both sides, a connecting shaft is rotatably arranged between the two chain connecting pins, a straight guide rail is arranged on the guide rail seat, an arc guide rail is extended from the top of the straight guide rail, the arc guide rail is connected to the top plate, a guide wheel is rotatably arranged in the two straight guide rails, a moving shaft is rotatably arranged between the two guide wheels, a feeding hopper is arranged between the connecting shaft and the moving shaft, and the moving shaft is located on the discharge end of the feeding hopper.

[0006] Furthermore, in the aforementioned three-stage center-pressure pre-pressing forming machine, a slide groove is provided on the top of the guide rail seat, a sprocket slider is slidably clamped in the slide groove, a rotating shaft is rotatably arranged in the sprocket slider, an adjusting block is arranged on the slide groove, an adjusting bolt is threadedly connected in the adjusting block, and the adjusting bolt is rotatably clamped in the sprocket slider.

[0007] Furthermore, in the aforementioned three-stage center-pressure pre-pressing forming machine, the connection structure between the discharge hopper and the top plate is as follows: a fixed frame is provided on the outer wall of the discharge hopper, four upper spring seats are provided around the fixed frame, a buffer frame is provided below the fixed frame, four lower spring seats are provided around the buffer frame, a buffer spring is provided between the upper and lower spring seats aligned vertically, four sliding sleeves are provided on the buffer frame, the four sliding sleeves are symmetrical in pairs, four guide pillars are provided on the top plate, the four sliding sleeves are slidably provided on the four guide pillars, two mounting blocks are also symmetrically provided on the buffer frame, two tension cylinders are provided on the top plate, and the piston rods on the two tension cylinders are respectively connected to the two mounting blocks.

[0008] Furthermore, in the aforementioned three-stage center-pressure pre-pressing forming machine, a shielding plate is mounted on the discharge end of the discharge hopper, and a vibration motor is arranged on the fixed frame.

[0009] Furthermore, in the aforementioned three-stage center-to-center pre-pressing forming machine, the connection structure between the orifice plate and the frame is as follows: an intermediate plate is arranged on the frame, an avoidance hole is opened on the intermediate plate, four columns are arranged between the intermediate plate and the top plate, the four columns are symmetrical in pairs, two lifting cylinders are symmetrically arranged on the intermediate plate, the piston rods of the lifting cylinders are connected to the orifice plate, a reinforcing plate is slidably arranged between the two columns on the same side, two reinforcing rods are arranged between the reinforcing plate and the orifice plate, and two are symmetrically arranged on the left side wall of the upper slide plate. A chain screw is connected to a counterweight chain, the counterweight block is connected to the counterweight chain, two gear seats are symmetrically arranged front and back on the left side wall of the orifice plate, a counterweight sprocket is rotatably arranged on the gear seat, the counterweight chain is connected to the counterweight sprocket on the same side, two upper guide rails are symmetrically arranged front and back on the orifice plate, a plurality of upper sliders are symmetrically arranged front and back on the upper slide plate, the upper sliders are slidably clamped on the upper guide rails on the corresponding side, a mounting hole is arranged on the upper slide plate, an upper clamp coaxial with the mounting hole is arranged on the upper slide plate, and the upper clamp is clamped on the upper barrel.

[0010] Furthermore, in the aforementioned three-stage center-pressure pre-pressing molding machine, a first positioning ring is mounted on the bottom end of the upper barrel, the first positioning ring extends downward from the upper barrel, the distance between the bottom wall of the first positioning ring and the bottom wall of the upper barrel is H, a first limiting ring is mounted on the top end of the middle barrel, the distance between the top wall of the first limiting ring and the top wall of the middle barrel is also H, a second positioning ring is mounted on the bottom end of the middle barrel, the second positioning ring extends downward from the middle barrel, the distance between the bottom wall of the second positioning ring and the bottom wall of the middle barrel is h, a second limiting ring is mounted on the top end of the lower barrel, the distance between the top wall of the second limiting ring and the top wall of the lower barrel is also h.

[0011] Furthermore, in the aforementioned three-stage center-to-center pre-pressing forming machine, the connection structure between the support plate and the middle barrel is as follows: positioning plates are provided at both upper and lower ends of the support plate, arc-shaped holes are provided on the positioning plates, a clamping plate is rotatably provided on the positioning plate, and an arc-shaped hole is also provided on the clamping plate. After the clamping plate and the positioning plate are rotated and matched, the middle barrel is clamped through the two arc-shaped holes, and a lower hoop is surrounded and provided on the outer side wall of the middle barrel, and the lower hoop is against the positioning plate and the clamping plate located at the upper end of the support plate, and is fixed on the fixed plate. A locking member capable of locking the positioning plate and the clamping plate is arranged between the positioning plate and the clamping plate, and the locking member includes: a sliding sleeve seat fixed on the side wall of the positioning plate and a top block fixed on the side wall of the clamping plate, a push rod is slidably arranged at one end of the sliding sleeve seat close to the top block, a handle is hinged at one end of the sliding sleeve seat away from the top block, a connecting rod is hinged between the handle and the push rod, an adjusting screw is threadedly connected in one end of the push rod close to the top block, a locking nut is threadedly connected on the adjusting screw, and the locking nut is screwed against the push rod.

[0012] Furthermore, in the aforementioned three-stage center-pressure pre-pressing forming machine, two lower guide rails are arranged on the bottom plate, a push-pull cylinder is horizontally arranged on the bottom plate between the two lower guide rails, the piston rod of the push-pull cylinder is connected to the lower slide plate, and a plurality of lower slide blocks are arranged on the front and rear sides of the lower slide plate, and the lower slide blocks are slidably clamped on the lower guide rails on the corresponding sides.

[0013] The method for using the three-stage center-to-center pre-pressing forming machine is as follows: the middle barrel is mounted on the support plate, the flip cylinder pushes the support plate to a vertical state, the middle barrel and the lower barrel are coaxially aligned, the lifting cylinder drives the support plate to descend, the middle barrel and the lower barrel are docked, the lower slide plate moves to the left and rests on the lower left limit seat, the middle barrel and the upper barrel are coaxially aligned, the orifice plate drives the upper barrel to descend, the upper barrel and the middle barrel are docked, and the lower slide plate carries the docked lower barrel, middle barrel and The upper barrel moves to the right and abuts against the lower right limit seat, the discharge hopper presses downward against the upper barrel, the feeding mechanism feeds the plastic into the discharge hopper and flows from the discharge hopper into the docked lower barrel, middle barrel and upper barrel. After the discharge is completed, the discharge hopper rises and leaves the upper barrel, and the lower slide drives the docked lower barrel, middle barrel and upper barrel to move to the left and abut against the lower left limit seat, the lower push cylinder drives the upper pressure head to extend into the upper barrel, and the upper push cylinder passes through the lower The slide plate extends into the lower barrel and pushes the lower pressure head. The upper and lower pressure heads squeeze the plastic at the same time, so that the plastic is compacted in the middle barrel. The lower push cylinder drives the upper pressure head to reset upward and disengage from the upper barrel, and the upper lifting cylinder resets downward and disengages from the lower slide plate. The orifice plate drives the upper barrel to rise and disengage from the middle barrel. The lower slide drives the middle barrel and the lower barrel to move right and rest against the right lower limit seat. The lifting cylinder drives the strong magnetic block to pass through the lower slide and adsorb on the lower pressure head and push the lower pressure head to the top of the lower barrel. The lifting cylinder drives the pallet to rise, and the middle barrel is separated from the lower barrel. The flip cylinder pushes the pallet and the middle barrel on the pallet to rotate to a horizontal state. The upper pressure head blocks the dense plastic from falling out of the middle barrel, and the lifting cylinder drives the strong magnetic block to reset downward with the lower pressure head. The lower pressure head returns to the lower barrel, and the staff removes the middle barrel filled with dense plastic from the pallet, and then installs the new middle barrel on the pallet.

[0014] The advantages of the present invention are: the upper pressure head and the lower pressure head extrude the plastic at the same time, and the bidirectional extrusion applies pressure on both sides at the same time, which effectively offsets the attenuation effect of friction, makes the overall force of the material more uniform, the density distribution more consistent, and reduces the internal loose area, and the bidirectional extrusion compresses the plastic from two directions, forcing the bubbles to be discharged outward through the pinholes, thereby reducing internal defects and improving the compactness of the plastic. The upper pressure head and the lower pressure head apply force at the same time to perform bidirectional extrusion, which can compact the plastic and accumulate it in the middle barrel, and then rotate the middle barrel to a horizontal state and remove it from the pallet, transport the middle barrel filled with dense plastic to the next station for material collection, and install the new middle barrel on the pallet to re-perform pre-compression work, so that the staff can continue to perform pre-compression work while the equipment is taking the material, thereby improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the three-stage center-pressure pre-pressing molding machine described in the present invention.

[0016] Figure 2 yes Figure 1Schematic diagram of the connection structure between the middle discharge hopper and the top plate.

[0017] Figure 3 yes Figure 1 Schematic diagram of the connection structure between the middle and upper barrel and the frame.

[0018] Figure 4 yes Figure 3 Schematic diagram of the cross-sectional structure.

[0019] Figure 5 yes Figure 1 Schematic diagram of the connection structure between the middle and lower barrels and the middle barrel and the bottom plate.

[0020] Figure 6 yes Figure 5 Schematic diagram of the cross-sectional structure.

[0021] Figure 7 yes Figure 5 Schematic diagram of the connection structure between the middle support plate and the middle barrel.

[0022] Figure 8 It is a schematic diagram of the structure of the upper barrel, the middle barrel and the lower barrel.

[0023] Fig. 9 yes Figure 1 Schematic diagram of the structure of the feeding mechanism.

[0024] Fig.10 It is a structural schematic diagram of the three-stage center-pressure pre-pressing molding machine of the present invention when the middle barrel is being disassembled and assembled. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and preferred embodiments.

[0026] like Figures 1 to 10As shown, the three-stage center-to-center pre-pressing forming machine of the present invention comprises: a frame 1, a top plate 11 is arranged on the top of the frame 1, a discharging hopper 2 and a downward-pushing oil cylinder 12 are arranged on the top plate 11, an upper pressing head 121 is arranged on the downward-pushing oil cylinder 12, a liftable orifice plate 13 is arranged on the frame 1 below the top plate 11, and a connection structure between the orifice plate 13 and the frame 1 is as follows: an intermediate plate 15 is arranged on the frame 1, an avoidance hole is opened on the intermediate plate 15, four columns 151 are arranged between the intermediate plate 15 and the top plate 11, and the four columns 151 Two lifting cylinders 152 are symmetrically arranged on the middle plate 15, and the piston rods of the lifting cylinders 152 are connected to the orifice plate 13. A reinforcing plate 153 is slidably arranged between the two columns 151 on the same side, and two reinforcing rods 154 are arranged between the reinforcing plate 153 and the orifice plate 13. The lifting cylinder 152 can drive the orifice plate 13 to rise and fall. By adding the reinforcing rods 154 and the reinforcing plate 153, the lifting stability of the orifice plate 13 can be improved. Two upper guide rails 131 are symmetrically arranged on the orifice plate 13, and an upper slider 132 is slidably arranged on the upper guide rail 131. An upper slide plate 133 is provided between the upper sliders 132, a mounting hole is provided on the upper slide plate 133, an upper clamp 1331 coaxial with the mounting hole is provided on the upper slide plate 133, a material barrel 3 is provided in the mounting hole, the material barrel 3 passes through the avoidance holes of the orifice plate 13 and the middle plate 15 and then extends downward from the middle plate 15, the upper clamp 1331 is clamped on the material barrel 3 to fix the material barrel 3 on the upper slide plate 133, a left upper limit seat 134 is provided on the left side of the orifice plate 13, when the upper slide plate 133 abuts against the left upper limit seat 134, the material barrel 3 and the upper pressure head are 121 is coaxially aligned, two chain screws are symmetrically arranged front and back on the left side wall of the upper slide plate 133, a counterweight chain 1332 is connected to the chain screw, a counterweight block 1333 is connected to the counterweight chain 1332, two gear seats are symmetrically arranged front and back on the left side wall of the orifice plate 13, a counterweight sprocket 135 is rotatably arranged on the gear seat, the counterweight chain 1332 is connected to the counterweight sprocket 135 on the same side, and the upper slide plate 133 will automatically rest against the left upper limit seat 134 under the gravity pull of the counterweight block 1333 and be coaxially aligned with the upper pressure head 121 on the push-down cylinder 12.

[0027] A bottom plate 14 is provided at the bottom of the frame 1, an upper oil cylinder 141 and a lower slide plate 142 which can slide left and right are provided on the bottom plate 14, two lower guide rails 143 are provided on the bottom plate 14, a push-pull cylinder 144 is horizontally provided on the bottom plate 14 between the two lower guide rails 143, a piston rod of the push-pull cylinder 144 is connected to the lower slide plate 142, a plurality of lower slide blocks 1421 are provided on the front and rear sides of the lower slide plate 142, and the lower slide blocks 1421 are slidably mounted on the lower slides on the corresponding sides. On the guide rail 143, a left lower limit seat 145 and a right lower limit seat 146 are respectively arranged on the left and right sides of the bottom plate 14, the left lower limit seat 145 is aligned with the left upper limit seat 134, a through hole 1422 is opened on the lower slide plate 142, a lower barrel 4 is connected to the lower slide plate 142 by bolts, the lower barrel 4 is coaxially aligned with the through hole 1422, and a heightening frame 5 is fixedly arranged on the lower slide plate 142. When the push-pull cylinder 144 drives the lower slide plate 142 to abut against the left lower limit seat 1 When the push-pull cylinder 144 drives the lower slide 142 to abut against the right lower limit seat 146, the lower barrel 4 is coaxially aligned with the discharge hopper 2. A lower pressure head 41 is provided in the lower barrel 4 in a movable seal. The lower pressure head 41 abuts against the lower slide 142 under its own weight. A material ejection cylinder 147 is provided on the bottom plate 14. When the push-pull cylinder 144 drives the lower slide 142 to abut against the right lower limit seat 146, the lower barrel 4 is coaxially aligned with the discharge hopper 2. A strong magnetic block 1471 is provided on the plug rod. When the ejection cylinder 147 is in a retracted state, the strong magnetic block 1471 will not interfere with the movement of the lower slide plate 142. When the lower slide plate 142 abuts against the lower right limit seat 146, the through hole 1422 on the lower slide plate 142 is aligned with the ejection cylinder 147 up and down, and the piston rod in the ejection cylinder 147 passes upward through the through hole 1422 on the lower slide plate 142 and contacts with the lower pressure head 41 in the lower barrel 4, thereby being able to push the lower pressure head 41 upward.

[0028] A hinged seat 51 is hinged on the elevated frame 5, and a lifting cylinder 52 is arranged on the hinged seat 51. The piston rod of the lifting cylinder 52 is connected to the support plate 6. Two rows of linear bearings 61 are arranged on the support plate 6. A guide rod 62 is slidably arranged in the linear bearings 61 on the same side. The guide rod 62 is fixed in the hinged seat 51. A detachable middle barrel 7 is arranged on the support plate 6. A flip cylinder 53 is hinged on the elevated frame 5. A coupling plate 63 is arranged between the two guide rods 62. The piston rod of the flip cylinder 53 is hinged to the coupling plate 63. Vertical limit seats 54 are arranged at the front and rear ends of the elevated frame 5. When the piston rod in the flipping cylinder 53 is extended, it can push the pallet 6 and the hinged seat 51 connected to the pallet 6 to rotate counterclockwise through the coupling plate 63. When the pallet 6 rotates and rests on the vertical limit seat 54, the pallet 6 and the middle barrel 7 on the pallet 6 are in a vertical state, and the lifting cylinder 52 can drive the pallet 6 to rise and fall. When the piston rod in the flipping cylinder 53 is contracted, it can pull the pallet 6 to rotate clockwise. When the piston rod in the flipping cylinder 53 is contracted into place, the pallet 6 rotates to a horizontal state.

[0029] Pinholes are provided on the side walls of the upper barrel 3, the middle barrel 7 and the lower barrel 4. A first positioning ring 31 is mounted on the bottom end of the upper barrel 3. The first positioning ring 31 extends downward from the upper barrel 3. The distance between the bottom wall of the first positioning ring 31 and the bottom wall of the upper barrel 3 is H. A first limiting ring 71 is mounted on the top end of the middle barrel 7. The distance between the top wall of the first limiting ring 71 and the top wall of the middle barrel 7 is also H. When the upper barrel 3 is docked with the middle barrel 7, the bottom wall of the upper barrel 3 abuts against the top wall of the middle barrel 7, and the first positioning ring 31 on the upper barrel 3 is sleeved on the outer wall of the middle barrel 7 and abuts against On the first limiting ring 71 of the middle barrel 7, a second positioning ring 72 is mounted on the bottom end of the middle barrel 7, and the second positioning ring 72 extends downward from the middle barrel 7, and the distance between the bottom wall of the second positioning ring 72 and the bottom wall of the middle barrel 7 is h. A second limiting ring 42 is mounted on the top end of the lower barrel 4, and the distance between the top wall of the second limiting ring 42 and the top wall of the lower barrel 4 is also h. When the middle barrel 7 is docked with the lower barrel 4, the bottom wall of the middle barrel 7 abuts against the top wall of the lower barrel 4, and the second positioning ring 7 on the middle barrel 7 is sleeved on the outer wall of the lower barrel 4 and abuts against the second limiting ring 42 of the lower barrel 4.

[0030] A feeding mechanism 8 capable of feeding materials into the discharge hopper 2 is arranged on the frame 1, and the feeding mechanism 8 includes: a fixing plate 81 arranged at the rear side of the frame 1. In this embodiment, the load of the frame 1 is heavy. In order to improve the installation strength of the frame 1, the supporting feet are generally pre-buried underground, and then the bottom plate 14 is fixed on the supporting feet and pressed against the ground. The load of the feeding mechanism 8 is light, so the fixing plate 81 is directly connected to the ground. Figure 1 and Fig.10It can be seen that the fixed plate 81 is flush with the bottom plate 14, two guide rail seats 811 and a dual-axis reduction motor 812 are vertically arranged on the fixed plate 81, and the two output shafts of the dual-axis reduction motor 812 are connected with a driving gear 82, a slide groove is opened on the top of the guide rail seat 811, a sprocket slider 83 is slidably clamped in the slide groove, an adjusting block 831 is arranged on the slide groove, an adjusting bolt 832 is threadedly connected in the adjusting block 831, the adjusting bolt 832 is rotatably clamped in the sprocket slider 83, a rotating shaft 813 is rotatably arranged between the sprocket sliders 83 of the two guide rail seats 811, and a driven gear 814 is arranged at both ends of the rotating shaft 813, a transmission chain is connected between the driving gear 82 and the driven gear 814 on the same side, and the transmission chain is not shown in the figure, and the adjusting bolt 832 is rotated to adjust the screw thread between the adjusting bolt 832 and the adjusting block 831. The transmission can adjust the height position of the sprocket slider 83, thereby adjusting the tension of the transmission chain. Chain connecting pins 84 are provided on the transmission chains on both sides. The connection structure between the chain connecting pin 84 and the transmission chain is the prior art. When the transmission chain is not shown, the technicians in this field know the connection structure between the chain connecting pin 84 and the transmission chain. A connecting shaft 841 is rotatably arranged between the two chain connecting pins 84, a straight guide rail 85 is arranged on the guide rail seat 811, and an arc guide rail 851 is extended from the top of the straight guide rail 85, and the arc guide rail 851 is connected to the top plate 11. A guide wheel 86 is rotatably arranged in the two straight guide rails 85, and a moving shaft 861 is rotatably arranged between the two guide wheels 86. A feeding hopper 87 is arranged between the connecting shaft 841 and the moving shaft 861, and the moving shaft 861 is located on the discharge end of the feeding hopper 87. Starting the dual-axis reduction motor 812 can drive the transmission chain to move clockwise or counterclockwise between the driving gear 82 and the driven gear 814, thereby driving the chain connecting pin 84 to rise and fall. During the lifting process, the two chain connecting pins 84 will drive the feeding hopper 87 to rise and fall through the connecting shaft 841. During the lifting process, the feeding hopper 87 will drive the two guide wheels 86 to move along the straight guide rail 85 and the arc guide rail 851 through the moving shaft 861. When the guide wheel 86 enters the arc guide rail 851, the feeding hopper 8 will rotate, and the discharge end of the feeding hopper 8 will dump into the discharge hopper 2 on the top plate 11, thereby pouring the material in the feeding hopper 8 into the discharge hopper 2.

[0031] When in use, the middle barrel 7 is installed on the support plate 6 in a horizontal state, and then the support plate 6 is pushed to rotate to a vertical state by the turning cylinder 53. At this time, the middle barrel 7 is coaxially aligned with the lower barrel 4, and then the support plate 6 and the middle barrel 7 on the support plate 6 are driven to descend by the lifting cylinder 52 until the lower end of the middle barrel 7 is engaged with the upper end of the lower barrel 4, and then the lower slide plate 142 is driven to move to the left by the push-pull cylinder 144 until the lower slide plate 142 abuts against the left lower limit seat 145. At this time, the docked lower barrel 4 and middle barrel 7 are coaxially aligned with the upper barrel 3 on the upper slide plate 133 abutting against the left upper limit seat 134, the orifice plate 13 descends to dock the upper barrel 3 with the middle barrel 7, and the push-pull cylinder 144 drives the lower slide plate 142 to move to the right. Until the lower slide plate 142 abuts against the lower right limit seat 146, since the upper barrel 3 is connected to the middle barrel 7, the lower slide plate 142 will move rightward with the upper slide plate 133 and the upper barrel 3 during the rightward movement. In order to prevent the discharge hopper 2 from interfering with the movement of the upper barrel 3, the discharge hopper 2 needs to be lifted upward. When the lower slide plate 142 abuts against the lower right limit seat 146, the docked upper barrel 3, middle barrel 7 and lower barrel 4 are coaxially aligned with the discharge hopper 2, and then the discharge hopper 2 descends and extends into the upper barrel 3, pouring the plastic into the feeding hopper 87 in the feeding mechanism 8. The feeding hopper 87 moves along the straight guide rail 85 and the arc guide rail 851 driven by the transmission chain. The feeding hopper 87 pours the plastic into the discharge hopper 2 when it is turned over, and then from the discharge hopper 2 The plastic will not overflow from the pinholes on the side walls of the upper barrel 3, the middle barrel 7 and the upper barrel 3. After the feeding is completed, the discharge hopper 2 is lifted upward, and the push-pull cylinder 144 drives the lower slide plate 142 to move to the left again until the lower slide plate 142 abuts against the lower left limit seat 145. The lower push cylinder 12 drives the upper press head 121 to extend into the upper barrel 3. The upper press head 121 is movably sealed with the upper barrel 3. The piston rod of the upper push cylinder 141 passes through the through hole 1422 on the lower slide plate 142 and extends into the lower barrel 4 to abut against the lower press head 145. 41, and then the push-down cylinder 12 and the upper cylinder 141 are started at the same time, the push-down cylinder 12 drives the upper pressure head 121 to squeeze the plastic downward, and the upper cylinder 141 drives the lower pressure head 41 to squeeze the plastic upward. The plastic will be compacted in the middle barrel 7 under the two-way extrusion of the upper pressure head 121 and the lower pressure head 41. During the extrusion process, the air in the plastic is discharged out through the pinhole. After the extrusion is completed, the push-down cylinder 12 drives the upper pressure head 121 upward away from the upper barrel 3, and the upper cylinder 141 drives the piston rod downward away from the lower barrel 4 and the lower slide plate 142. When the lower pressure head 41 loses the support of the upper cylinder 141, the compacted plastic and the lower pressure head 41 are easily dropped into the lower barrel 4 under their own weight, and the orifice plate 13 rises to separate the upper barrel 3 from the middle barrel 7.The upper slide plate 133 abuts against the left upper limit seat 134 under the pulling force of the counterweight block 1333, and the push-pull cylinder 144 drives the lower slide plate 142 to move rightward again until the lower slide plate 142 abuts against the right lower limit seat 146. At this time, the through hole 1422 on the lower slide plate 142 is aligned with the ejection cylinder 147 up and down, and the ejection cylinder 147 drives the strong magnetic block 1471 to pass through the through hole 1422 upward and magnetically attract the lower pressure head 41, and then push the lower pressure head 41 upward to The lower pressure head 41 pushes to the top of the lower barrel 4. At this time, the dense plastic accumulated on the lower pressure head 41 is in the middle barrel 7. Then the lifting cylinder 52 drives the support plate 6 to rise, and the middle barrel 7 on the support plate 6 is separated from the lower barrel 4. Then, the flip cylinder 53 pushes the support plate 6 and the middle barrel 7 to rotate to a horizontal state. During the flipping process, the dense plastic will flip with the middle barrel 7. The lower pressure head 41 blocks the dense plastic to prevent it from falling from the middle barrel 7. When the dense plastic turns over with the middle barrel 7, the contact surface with the lower pressure head 41 will be reduced. When the middle barrel 7 is tilted, the dense plastic will increase the adhesion strength with the side wall of the middle barrel 7 under gravity. Therefore, the more the middle barrel 7 tends to be horizontal, the greater the adhesion strength between the dense plastic and the middle barrel 7. Therefore, the lower pressure head 41 only needs to block the dense plastic when the middle barrel 7 is in a vertical state. After the middle barrel 7 starts to tilt, the dense plastic is not easy to fall out of the middle barrel 7. After the middle barrel 7 rotates to a horizontal state, the ejection cylinder 147 drives the strong magnetic block 1471 to shrink and reset with the lower pressure head 41, and the lower pressure head 41 returns to the lower barrel 4. The strong magnetic block 1471 retracts to a position where it does not interfere with the movement of the lower slide 142. The staff removes the middle barrel 7 filled with dense plastic from the support plate 6 and sends it to the next station for processing, and then installs the empty middle barrel 7 on the support plate 6 for subsequent work.

[0032] In order to improve the connection strength and disassembly efficiency between the middle barrel 7 and the support plate 6, in this embodiment, the connection structure between the support plate 6 and the middle barrel 7 is as follows: positioning plates 64 are provided at the upper and lower ends of the support plate 6, and arc-shaped holes are provided on the positioning plates 64. An adapter plate 641 is rotatably provided on the positioning plate 64, and a clamping plate 65 is provided on the adapter plate 641. An arc-shaped hole is also provided on the clamping plate 65. After the clamping plate 65 is rotated and matched with the positioning plate 64, the middle barrel 7 is clamped through the two arc-shaped holes. A lower hoop 73 is surrounded and provided on the outer side wall of the middle barrel 7. The lower hoop 73 abuts against the positioning plate 64 and the clamping plate 65 at the upper end of the support plate 6, and the positioning plate 64 and the clamping plate 65 at the lower end of the support plate 6 abut against the second positioning plate of the middle barrel 7. On the ring 72, a locking member capable of locking the positioning plate 64 and the clamping plate 65 is provided between the positioning plate 64 and the clamping plate 65, and the locking member includes: a sliding seat 66 fixed on the side wall of the positioning plate 64 and a top block 67 fixed on the side wall of the clamping plate 65, a push rod 661 is slidably provided at one end of the sliding seat 66 close to the top block 67, a handle 662 is hinged at one end of the sliding seat 66 away from the top block 67, a connecting rod 663 is hinged between the handle 662 and the push rod 661, an adjusting screw 664 is threadedly connected in one end of the push rod 661 close to the top block 67, a locking nut 665 is threadedly connected on the adjusting screw 664, and the locking nut 665 is screwed against the push rod 661 to lock the adjusting screw 664. When disassembling the middle barrel 7, the support plate 6 is rotated to a horizontal state, the lower hoop 73 is removed, and then the handle 662 is pulled away from the top block 67. The handle 662 pulls the top rod 661 out of the top block 67 through the connecting rod 663, and the clamping plate 65 is opened to remove the middle barrel 7 filled with dense plastic from the positioning plate 64. Then, the new middle barrel 7 is placed in the arc-shaped holes of the two positioning plates 64, wherein the second positioning ring 72 of the new middle barrel 7 abuts against the positioning plate 64 and the positioning plate 64 at the lower end of the support plate 6. The clamping plate 65 is placed on the support plate 65, so that the new middle barrel 7 can be quickly positioned. When the support plate 6 is in a horizontal state, the positioning plate 64 and the clamping plate 65 at the lower end of the support plate 6 are located on the left side, and then the clamping plate 65 is rotated to align, and then the handle 66 is pulled in the direction of the top block 67, driving the top rod 661 to abut against the top block 67 so that the positioning plate 64 corresponding to the clamping plate 65 clamps the middle barrel 7, and then the lower clamping hoop 73 is clamped on the middle barrel 7 and abuts against the positioning plate 64 and the clamping plate 65 at the upper end of the support plate 6.

[0033] When compressing different types of plastics, since the compression ratios of different types of plastics are different, it is necessary to replace the upper barrel 3, the middle barrel 7 and the lower barrel 4 of different diameters according to the different types of plastics. When replacing the upper barrel 3, it is only necessary to replace the matching upper clamp 1331 to fix the upper barrel 3 of different diameters on the upper slide 133. When replacing the lower barrel 4, it is only necessary to directly fix it on the lower slide 142 by bolts. When replacing the middle barrel 7, it is necessary not only to replace the matching lower clamp 73, but also to screw the adjusting screw 664 to extend the length of the ejector rod 661. Or shorten the length of the push rod 661. When the length of the push rod 661 is extended, the push rod 661 pushes on the top block 67 to increase the rotation angle of the clamping plate 65, thereby reducing the clamping hole diameter between the clamping plate 65 and the positioning plate 64, and the clamping plate 65 and the positioning plate 64 can clamp the middle barrel 7 with a smaller diameter. When the length of the push rod 661 is shortened, the push rod 661 pushes on the top block 67 to reduce the rotation angle of the clamping plate 65, thereby increasing the clamping hole diameter between the clamping plate 65 and the positioning plate 64, and the clamping plate 65 and the positioning plate 64 can clamp the middle barrel 7 with a larger diameter, thereby increasing the scope of application.

[0034] In this embodiment, the connection structure between the discharge hopper 2 and the top plate 11 is as follows: a fixed frame 21 is provided on the outer wall of the discharge hopper 2, four upper spring seats 211 are provided around the fixed frame 21, a buffer frame 22 is provided below the fixed frame 21, four lower spring seats 221 are provided around the buffer frame 22, a buffer spring 23 is provided between the upper spring seat 211 and the lower spring seat 221 aligned up and down, and four sliding sleeves 222 are provided on the buffer frame 22. The four sliding sleeves 222 are symmetrical in pairs, and four guide pillars 111 are arranged on the top plate 11. The four sliding sleeves 222 are slidably arranged on the four guide pillars 111. Two mounting blocks 223 are also symmetrically arranged on the buffer frame 22. Two tension cylinders 112 are arranged on the top plate 11, and the piston rods on the two tension cylinders 112 are respectively connected to the two mounting blocks 223. A material shielding plate 24 is mounted on the discharging end of the discharging hopper 2, and a vibration motor 212 is arranged on the fixed frame 21. The tension cylinder 112 can drive the discharge hopper 2 to rise and fall. When the upper barrel 3 is coaxially aligned with the discharge hopper 2, the tension cylinder 112 drives the discharge hopper 2 to descend, and the discharge hopper 2 extends into the upper barrel 3. The shielding plate 24 on the discharge hopper 2 rests against the upper barrel 3 to play a limiting role. When the discharge hopper 2 is discharging materials, the vibration of the vibration motor 212 can improve the discharge effect and efficiency of the plastic. When the vibration motor 212 vibrates the discharge hopper 2, due to the buffering effect of the buffer spring 23, the vibration effect will not be transmitted to the top plate 11 to cause resonance.

[0035] In this embodiment, the automation degree and operation accuracy are improved by adding some induction switches and electrically connecting them to the PLC equipment. The tension cylinder 112 is a through-type cylinder, that is, the piston rod of the tension cylinder 112 runs through the entire cylinder and extends from both ends. The upper end of the piston rod of the tension cylinder 112 is connected to the mounting block 223. A first induction block 1121 is provided at the lower end of the piston rod of the tension cylinder 112. A first switch support rod 1122 is vertically provided on the tension cylinder 112. A first upper limit induction switch 1123 and a first lower limit induction switch 1124 are provided at the upper and lower ends of the first switch support rod 1122, respectively. When the tension cylinder 112 drives the discharge hopper 2 to rise and fall, the tension cylinder 112 The first sensing block 1121 on the cylinder 112 can be sensed by the first upper limit sensing switch 1123 or the first lower limit sensing switch 1124. When the first sensing block 1121 on the tension cylinder 112 is sensed by the first upper limit sensing switch 1123, it means that the discharge hopper 2 has risen into place and will not interfere with the movement of the upper barrel 3. When the first sensing block 1121 on the tension cylinder 112 is sensed by the first lower limit sensing switch 1124, it means that the discharge hopper 2 has descended to extend into the upper barrel 3 and the shielding plate 24 on the discharge hopper 2 is against the upper barrel 3.

[0036] The lifting cylinder 152 is also a through-type cylinder, and a second sensing block 1521 is arranged at the lower end of the piston rod of the lifting cylinder 152, and a second switch support rod 155 is arranged on the middle plate 15, and a second upper limit sensing switch 1551 and a second lower limit sensing switch 1552 are respectively arranged at the upper and lower ends of the second switch support rod 155. When the lifting cylinder 152 drives the orifice plate 13 to rise and fall, the second sensing block 1521 on the lifting cylinder 152 can be sensed by the second upper limit sensing switch 1551 or the second lower limit sensing switch 1552. When the second sensing block 1521 is sensed by the second upper limit sensing switch 1551, it indicates that the upper barrel 3 on the orifice plate 13 moves upward to a height position that is separated from the middle barrel 7. When the second sensing block 1521 is sensed by the second lower limit sensing switch 1552, it indicates that the upper barrel 3 on the orifice plate 13 is clamped downward with the middle barrel 7.

[0037] A left sensing switch 136 and a right sensing switch 137 are respectively provided on the left and right sides of the orifice plate 13. The distance between the left sensing switch 136 and the right sensing switch 137 is greater than the left and right widths of the upper slide plate 133. When the upper slide plate 133 abuts against the left upper limit seat 134, the left sensing switch 136 senses the upper slide plate 133, and the right sensing switch 137 does not sense the upper slide plate 133. If the second upper limit sensing switch 1551 senses the second sensing block 1521 at this time, it means that the orifice plate 13 and the upper barrel 3 are in a lifting state, that is, the upper barrel 3 and the middle barrel 7 are in a separated state, and the loading has not been completed, and the push-down cylinder 12 and the upper cylinder 141 will not move. If the second lower limit sensing switch 1552 senses the second sensing block 1521 at this time, it means that the orifice plate 13 and the upper barrel 3 are in a lifting state, that is, the upper barrel 3 and the middle barrel 7 are in a separated state, and the loading has not been completed, the push-down cylinder 12 and the upper cylinder 141 will not move. 3 and the upper barrel 3 are in a descending state, that is, the upper barrel 3 and the middle barrel 7 are in a docking state, and the loading has been completed, the push cylinder 12 and the upper cylinder 141 will start to move, and when the upper slide plate 133 moves to the right and is sensed by the right sensing switch 137, and the left sensing switch 136 cannot sense the upper slide plate 133, the lower slide plate 142 rests on the lower right limit seat 146. Since the upper slide plate 133 must rely on the push-pull cylinder 144 to drive the lower slide plate 142 to move to the right, when the upper slide plate 133 is sensed by the right sensing switch 137, it means that the upper barrel 3, the middle barrel 7 and the lower barrel 4 are docked together in sequence and coaxially aligned with the discharge hopper 2, the feeding mechanism 8 can feed the plastic into the discharge hopper 2 and then flow into the docked upper barrel 3, the middle barrel 7 and the lower barrel 4.

[0038] A stretch sensor 113 and a transition roller 114 are provided on the top plate 11. The pull rope in the stretch sensor 113 is connected to the upper pressure head 121 after passing through the transition roller 114. When the push cylinder 12 drives the upper pressure head 121 to move downward, it pulls the pull rope in the stretch sensor 113. The stretch sensor 113 can record the running speed and distance of the upper pressure head 121, which is convenient for PLC control. A third upper limit sensing switch 115 is provided on the top plate 11. The third upper limit sensing switch 115 cooperates with the upper pressure head 121. When the upper pressure head 121 moves downward, the third upper limit sensing switch 115 is connected to the upper pressure head 121. When it is reset upward to the position sensed by the third upper limit sensing switch 115, it means that the upper pressure head 121 has risen to a position where it will not interfere with the movement of the upper barrel 3. A third lower limit sensing switch 148 is provided on the bottom plate 14. The third lower limit sensing switch 148 cooperates with the piston rod in the upper cylinder 141. When the piston rod in the upper cylinder 141 is reset downward to the position sensed by the third lower limit sensing switch 148, it means that the piston rod in the upper cylinder 141 has descended to a position where it will not interfere with the movement of the lower slide plate 142.

[0039] A fourth upper limit sensing switch 8111 and a fourth lower limit sensing switch 8112 are respectively provided at the upper and lower ends of the two guide rail seats 811. When the hopper 87 is at the lowest position, the connecting shaft 841 on the hopper 87 can be sensed by the two fourth lower limit sensing switches 8112. When the hopper 87 turns over and discharges materials under the guidance of the arc guide rail 851, the connecting shaft 841 on the hopper 87 can be sensed by the two fourth upper limit sensing switches 8111. A speed limit sensing switch 8113 is provided on any one of the guide rail seats 811. The position of the speed limit sensing switch 8113 is lower than the transition between the straight guide rail 85 and the arc guide rail 851. The hopper 87 can move up and down at a faster speed in the straight guide rail 85. When the moving shaft 861 on the hopper 87 is sensed by the speed limit sensing switch 8113, it indicates that the hopper 87 is in a state of being ... When the feeding hopper 87 is about to enter the arc guide rail 851 for flipping and unloading, the PLC can be used to control the dual-axis reduction motor 812 to reduce the rotation speed, thereby reducing the running speed of the feeding hopper 87, to prevent the situation where the flipping speed is too large due to the running speed being too fast and the material is spilled out. When flipping and unloading, the connecting shaft 841 on the feeding hopper 87 will continue to move upward and be sensed by the speed limit sensing switch 8113. After continuously sensing the moving shaft 861 and the connecting shaft 841, the speed limit sensing switch 8113 will form a control node in the PLC. After the feeding hopper 87 completes unloading, when the feeding hopper 87 is resetting, the connecting shaft 841 and the moving shaft 861 on the feeding hopper 87 are continuously sensed by the speed limit sensing switch 8113, and the PLC can control the dual-axis reduction motor 812 to increase the rotation speed, thereby increasing the running speed of the feeding hopper 87, thereby achieving the effect of rapid resetting.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. Three-stage center-pressure pre-pressing forming machine, including: The frame is characterized in that: a top plate is arranged on the top of the frame, a liftable discharging hopper and a push-down cylinder are arranged on the top plate, an upper pressure head is arranged on the push-down cylinder, a liftable orifice plate is arranged on the frame located below the top plate, an upper slide plate is arranged on the orifice plate for sliding left and right, a loading barrel passing through the orifice plate is fixedly arranged on the upper slide plate, a left upper limit seat is arranged on the left side of the orifice plate, when the upper slide plate abuts against the left upper limit seat, the loading barrel is coaxially aligned with the upper pressure head, two counterweights are symmetrically arranged front and back on the left side wall of the upper slide, a bottom plate is arranged at the bottom of the frame, an upper top cylinder and a lower slide plate which can slide left and right are arranged on the bottom plate, a through hole is arranged on the lower slide plate, a loading barrel and a heightening frame are fixedly arranged on the lower slide plate, a left lower limit seat and a right lower limit seat are respectively arranged on the left and right sides of the bottom plate, the left lower limit seat is aligned up and down with the left upper limit seat, and when the lower slide abuts against the right lower limit seat, the loading barrel is coaxially aligned with the upper pressure head, The cylinder is coaxially aligned with the discharge hopper, a lower pressure head is provided in the movable seal in the discharge cylinder, a material ejecting cylinder is provided on the bottom plate, a strong magnetic block is provided on the piston rod of the material ejecting cylinder, an articulated seat is hinged on the elevated frame, a lifting cylinder is provided on the articulated seat, the piston rod of the lifting cylinder is connected to the support plate, two rows of linear bearings are provided on the support plate, a guide rod is slidably provided in the linear bearing on the same side, the guide rod is fixed in the articulated seat, and a detachable A middle barrel is hinged with a turning cylinder on the elevated frame, a connecting plate is arranged between the two guide rods, the piston rod of the turning cylinder is hinged with the connecting plate, vertical limit seats are arranged at the front and rear ends of the elevated frame, pinholes are arranged on the side walls of the upper barrel, the middle barrel and the lower barrel, the bottom end of the upper barrel can be connected with the top end of the middle barrel, and the bottom end of the middle barrel can be connected with the top end of the lower barrel, and a feeding mechanism capable of feeding materials into the discharge hopper is arranged on the frame.

2. The three-stage center-pressure pre-pressing forming machine according to claim 1 is characterized in that: The feeding mechanism includes: a connection structure between the feeding hopper and the frame: a fixed plate arranged at the rear side of the frame, two guide rail seats and a double-axis reduction motor are vertically arranged on the fixed plate, a driving gear is connected to the two output shafts of the double-axis reduction motor, a rotating shaft is rotatably arranged between the tops of the two guide rail seats, a driven gear is arranged at both ends of the rotating shaft, a transmission chain is connected between the driving gear and the driven gear on the same side, a chain connecting pin is arranged on the transmission chains on both sides, a connecting shaft is rotatably arranged between the two chain connecting pins, a straight guide rail is arranged on the guide rail seat, an arc guide rail is extended from the top of the straight guide rail, the arc guide rail is connected to the top plate, a guide wheel is rotatably arranged in the two straight guide rails, a moving shaft is rotatably arranged between the two guide wheels, a feeding hopper is arranged between the connecting shaft and the moving shaft, and the moving shaft is located on the discharge end of the feeding hopper.

3. The three-stage center-pressure pre-pressing forming machine according to claim 2 is characterized in that: A slide groove is provided on the top of the guide rail seat, a sprocket slider is slidably clamped in the slide groove, a rotating shaft is rotatably arranged in the sprocket slider, an adjusting block is arranged on the slide groove, an adjusting bolt is threadedly connected in the adjusting block, and the adjusting bolt is rotatably clamped in the sprocket slider.

4. The three-stage center-pressure pre-pressing forming machine according to claim 1 is characterized in that: The connection structure between the discharge hopper and the top plate is as follows: a fixed frame is provided on the outer side wall of the discharge hopper, four upper spring seats are provided around the fixed frame, a buffer frame is provided below the fixed frame, four lower spring seats are provided around the buffer frame, a buffer spring is provided between the upper and lower spring seats aligned up and down, four sliding sleeves are provided on the buffer frame, the four sliding sleeves are symmetrical in pairs, four guide pillars are provided on the top plate, the four sliding sleeves are slidably provided on the four guide pillars, two mounting blocks are symmetrically provided on the buffer frame, two tension cylinders are provided on the top plate, and the piston rods on the two tension cylinders are respectively connected to the two mounting blocks.

5. The three-stage center-pressure pre-pressing forming machine according to claim 4 is characterized in that: A material shielding plate is mounted on the discharging end of the discharging hopper, and a vibration motor is arranged on the fixing frame.

6. The three-stage center-pressure pre-pressing forming machine according to claim 1 is characterized in that: The connection structure between the orifice plate and the frame is as follows: an intermediate plate is arranged on the frame, an avoidance hole is opened on the intermediate plate, four columns are arranged between the intermediate plate and the top plate, the four columns are symmetrical in pairs, two lifting cylinders are symmetrically arranged on the intermediate plate, the piston rods of the lifting cylinders are connected to the orifice plate, a reinforcing plate is slidably arranged between the two columns on the same side, two reinforcing rods are arranged between the reinforcing plate and the orifice plate, two chain screws are symmetrically arranged on the left side wall of the upper slide plate, and the chain screws are connected to the chain screws. A counterweight chain is connected, and the counterweight block is connected to the counterweight chain. Two gear seats are symmetrically arranged on the left side wall of the orifice plate. A counterweight sprocket is rotatably arranged on the gear seat. The counterweight chain is connected to the counterweight sprocket on the same side. Two upper guide rails are symmetrically arranged on the orifice plate. Several upper sliders are symmetrically arranged on the upper slide. The upper sliders are slidably clamped on the upper guide rails on the corresponding side. A mounting hole is arranged on the upper slide. An upper clamp coaxial with the mounting hole is arranged on the upper slide, and the upper clamp is clamped on the upper barrel.

7. The three-stage center-pressure pre-pressing forming machine according to claim 1 is characterized in that: A first positioning ring is mounted on the bottom end of the upper barrel, and the first positioning ring extends downward from the upper barrel. The distance between the bottom wall of the first positioning ring and the bottom wall of the upper barrel is H. A first limiting ring is mounted on the top end of the middle barrel, and the distance between the top wall of the first limiting ring and the top wall of the middle barrel is also H. A second positioning ring is mounted on the bottom end of the middle barrel, and the second positioning ring extends downward from the middle barrel. The distance between the bottom wall of the second positioning ring and the bottom wall of the middle barrel is h. A second limiting ring is mounted on the top end of the lower barrel, and the distance between the top wall of the second limiting ring and the top wall of the lower barrel is also h.

8. The three-stage center-pressure pre-pressing forming machine according to claim 1 is characterized in that: The connecting structure between the support plate and the middle barrel is as follows: a positioning plate is provided at the upper and lower ends of the support plate, an arc hole is provided on the positioning plate, a clamping plate is rotatably provided on the positioning plate, and an arc hole is also provided on the clamping plate. After the clamping plate and the positioning plate are rotated and matched, the middle barrel is clamped through the two arc holes. A lower clamping hoop is surrounded and provided on the outer wall of the middle barrel, and the lower clamping hoop abuts against the positioning plate and the clamping plate at the upper end of the support plate. A locking member capable of locking the positioning plate and the clamping plate is provided between the positioning plate and the clamping plate. The locking member comprises: a sliding sleeve seat fixed on the side wall of the positioning plate and a top block fixed on the side wall of the clamping plate, a push rod is slidably provided at one end of the sliding sleeve seat close to the top block, a grip is hinged at one end of the sliding sleeve seat away from the top block, a connecting rod is hinged between the grip and the push rod, an adjusting screw is threadedly connected at one end of the push rod close to the top block, a locking nut is threadedly connected on the adjusting screw, and the locking nut is screwed and abutted against the push rod.

9. The three-stage center-pressure pre-pressing forming machine according to claim 1, characterized in that: Two lower guide rails are arranged on the bottom plate, a push-pull cylinder is arranged horizontally on the bottom plate between the two lower guide rails, the piston rod of the push-pull cylinder is connected with the lower slide plate, a plurality of lower slide blocks are arranged on the front and rear sides of the lower slide plate, and the lower slide blocks are slidably clamped on the lower guide rails on the corresponding sides.

10. A method for using the three-stage center-pressure pre-pressing molding machine according to any one of claims 1 to 9, characterized in that: The upper and lower limit seats are aligned coaxially, and the lower push cylinder drives the upper pressure head to extend into the upper barrel, and the upper top cylinder passes through the lower slide and extends into the middle barrel to push the upper barrel in the middle position. The upper and lower pressure heads are pushed down, and the upper and lower pressure heads squeeze the plastic at the same time, so that the plastic is compacted in the middle barrel. The lower push cylinder drives the upper pressure head to reset upward and disengage from the upper barrel, and the upper lifting cylinder resets downward and disengages from the lower slide. The orifice plate drives the upper barrel to rise and disengage from the middle barrel, and the lower slide drives the middle barrel and the lower barrel to move to the right and rest against the lower right limit seat. The lifting cylinder drives the strong magnetic block to pass through the lower slide and adsorb on the lower pressure head and push the lower pressure head to the top of the lower barrel. The lifting cylinder drives the pallet to rise, and the middle barrel is separated from the lower barrel. The flip cylinder pushes the pallet and the middle barrel on the pallet to rotate to a horizontal state. The upper pressure head blocks the compacted plastic from falling out of the middle barrel, and the lifting cylinder drives the strong magnetic block to reset downward with the lower pressure head, and the lower pressure head returns to the lower barrel. The staff removes the middle barrel filled with compacted plastic from the pallet, and then installs the new middle barrel on the pallet.

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