A plastic bucket extrusion blow molding machine

Abstract

This utility model relates to the field of plastic bucket manufacturing technology and discloses a plastic bucket extrusion blow molding hollow forming machine, including a frame, an extrusion assembly, a lifting device, and a mold clamping device; the lifting device includes two ball screws mounted on the bottom of the inner cavity of the frame via bearings, each ball screw having a ball nut threadedly connected to its surface, and a support plate fixedly connected to the surface of the ball nut; one end of each of the two ball screws is connected to a first synchronous pulley and a second synchronous pulley, which are connected by a synchronous belt; the inner surface of the synchronous belt has multiple protrusions evenly distributed circumferentially, and the outer circumferential surfaces of the first and second synchronous pulleys have grooves adapted to the protrusions; the inner cavity of the frame is provided with a tensioning mechanism, which includes a connecting rod slidably connected to the frame, a tensioning wheel rotatably connected to the inner cavity of the connecting rod, a compression spring between the connecting rod and the frame, and the outer circumferential surface of the tensioning wheel rolling contact with the outer surface of the synchronous belt.

Description

Technical Field

[0001] This utility model relates to the field of plastic bucket manufacturing technology, specifically a plastic bucket extrusion blow molding hollow forming machine. Background Technology

[0002] A plastic bucket extrusion blow molding machine is a specialized piece of machinery used to manufacture hollow plastic products such as buckets, cans, and bottles. This equipment enables a continuous production process from raw plastic materials to finished products, improving production efficiency and reducing costs. It is widely used in the chemical, food, and pharmaceutical industries. Its working principle involves first heating and softening plastic granules or other raw materials to meet the requirements for plastic processing. The softened plastic raw material is then fed into an extruder, where it is extruded by a rotating screw. The high-speed rotation generates heat, causing the molten plastic to form a continuous hollow tubular or solid strip material. This tubular or strip material is then molded into a hollow product of a specific shape using a mold. The molded plastic product needs to be cooled in a water tank to rapidly solidify the plastic at a low temperature, shaping it into the desired form. After cooling and solidification, the product is removed from the mold and processed to the required dimensions using cutting equipment, resulting in the final plastic bucket or other hollow product.

[0003] Chinese Patent Publication No. (CN221660056U) discloses a hollow blow molding machine for plastic buckets, including a main body device for extruding a preform and moving the mold clamp. The bottom of the main body device is provided with an air blowing device for lifting and extending into the mold cavity to blow air and shape the preform. It also includes a support device provided on one side of the air blowing device for lifting and supporting the preform and limiting its sway when extending into the preform at two stations. The support device includes a lifting frame, on which two lifting screws are symmetrically installed front and rear. Synchronous pulleys are provided at the bottom of the lifting screws.

[0004] In the lifting device mentioned above, synchronous belt drive is widely used to connect the lead screws on both sides. The lead screws are driven to rotate by the synchronous belt, thereby realizing the lifting and lowering movement of the pallet and effectively lifting the blank. However, during long-term operation, the slippage phenomenon caused by tension decay of the synchronous belt is common. This directly affects the consistency of the rotation speed of the lead screws on both sides. If the rotation speed of the lead screws on both sides is inconsistent, it will cause different degrees of synchronization problems in the lifting and lowering process of the pallet, further aggravating the shaking of the blank and increasing the risk and the possibility of material damage in the production process.

[0005] In view of this, the present invention solves the above-mentioned technical problems by proposing a plastic bucket extrusion blow molding hollow forming machine. Utility Model Content

[0006] To address the shortcomings of the aforementioned background technology, this utility model provides a technical solution for a plastic bucket extrusion blow molding hollow forming machine. The tensioning mechanism uses a spring to push the tensioning wheel to press the outer side of the synchronous belt in real time, automatically compensating for the tension decay of the synchronous belt during long-term operation. Combined with the meshing transmission between the inner protrusion of the synchronous belt and the groove of the synchronous wheel, the slippage phenomenon caused by the looseness of the traditional synchronous belt is completely eliminated. The speed consistency error of the ball screws on both sides is reduced, and the synchronous error of the pallet lifting is reduced.

[0007] This utility model provides the following technical solution: a plastic bucket extrusion blow molding hollow forming machine, including a frame, an extrusion assembly, a lifting device and a mold closing device;

[0008] The lifting device includes two ball screws mounted on the bottom of the inner cavity of the frame via bearings. Each ball screw has a ball nut threaded onto its surface, and a support plate is fixedly connected to the surface of the ball nut.

[0009] One end of each of the two ball screws is connected to a first synchronous pulley and a second synchronous pulley, respectively, and the first synchronous pulley and the second synchronous pulley are connected by a synchronous belt drive.

[0010] The inner surface of the synchronous belt is evenly distributed with multiple protrusions along the circumference, and the outer peripheral surfaces of the first and second synchronous pulleys are provided with grooves that are adapted to the protrusions.

[0011] The inner cavity of the frame is provided with a tensioning mechanism, which includes a connecting rod slidably connected to the frame, a tensioning wheel rotatably connected to the inner cavity of the connecting rod, a compression spring between the connecting rod and the frame, and the outer peripheral surface of the tensioning wheel rolling contact with the outer surface of the synchronous belt.

[0012] As a preferred technical solution of this utility model, the top of the pallet is fixedly connected to two tube sleeves, and one end of each tube sleeve is provided with an axially penetrating through hole. The top of the frame is fixedly connected to two air blowing pipes, the axis of each air blowing pipe coincides with the axis of the through hole, and the outer diameter of the air blowing pipe is smaller than the inner diameter of the through hole.

[0013] As a preferred embodiment of this utility model, the two air blowing pipes are connected by an air inlet pipe, and the air inlet end of the air inlet pipe is provided with a quick-connect air pipe connector.

[0014] As a preferred embodiment of this utility model, an installation plate is fixedly connected to the inner cavity of the frame, and a servo motor is fixedly connected to the bottom of the installation plate by bolts. The output shaft of the servo motor is connected to the central shaft of the first synchronous pulley by a coupling.

[0015] As a preferred embodiment of the present invention, the mold closing device includes a guide groove formed on the opposite side of the frame, and two mold closing seats are slidably connected in the guide groove, with a split mold fixed on the opposite side of each of the two mold closing seats.

[0016] As a preferred embodiment of this utility model, one side of one of the split molds is fixedly connected with a plurality of guide pillars, and the other side of the split mold is provided with a guide hole adapted to the guide pillars, wherein the outer diameter of the guide pillars and the inner diameter of the guide hole are clearance-fitted.

[0017] As a preferred embodiment of this utility model, double-acting hydraulic cylinders are fixedly connected to both sides of the inner cavity of the frame, and the ends of the telescopic rods of the double-acting hydraulic cylinders are connected to the outer side of the mold clamping seat through ball joints.

[0018] As a preferred embodiment of this utility model, pressure sensors are respectively installed in the oil circuits of the rod chamber and the rodless chamber of the double-acting hydraulic cylinder.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The tensioning mechanism of this utility model uses a spring to push the tensioning wheel to press the outer side of the synchronous belt in real time, automatically compensating for the tension decay of the synchronous belt during long-term operation. Combined with the meshing transmission between the inner protrusion of the synchronous belt and the groove of the synchronous wheel, it completely eliminates the slippage phenomenon caused by the looseness of the traditional synchronous belt, reduces the speed consistency error of the ball screws on both sides, and reduces the synchronous error of the lifting of the pallet. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of this utility model;

[0022] Figure 2 This is the front view of the present invention;

[0023] Figure 3 This is a cross-sectional view of the present invention;

[0024] Figure 4 This is a schematic diagram of the tensioning wheel structure of this utility model.

[0025] In the diagram: 1. Frame; 101. Extrusion assembly; 2. Ball screw; 201. Ball nut; 202. Support plate; 203a. First synchronous pulley; 203b. Second synchronous pulley; 204. Synchronous belt; 205. Protrusion; 206. Groove; 207. Connecting rod; 208. Tensioning wheel; 209. Compression spring; 3. Tube sleeve; 301. Through hole; 302. Air blowing pipe; 4. Air inlet pipe; 401. Quick-connect air pipe connector; 5. Mounting plate; 501. Servo motor; 6. Guide groove; 601. Mold closing base; 602. Split mold; 7. Guide post; 701. Guide hole; 8. Double-acting hydraulic cylinder. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0027] Please see Figure 1-4 As shown, a plastic bucket extrusion blow molding machine includes a frame 1, an extrusion assembly 101, a lifting device, and a mold closing device.

[0028] The lifting device includes two ball screws 2 mounted on the bottom of the inner cavity of the frame 1 via bearings. Each ball screw 2 has a ball nut 201 threadedly connected to its surface, and a support plate 202 is fixedly connected to the surface of the ball nut 201.

[0029] One end of each of the two ball screws 2 is connected to the first synchronous pulley 203a and the second synchronous pulley 203b respectively. The first synchronous pulley 203a and the second synchronous pulley 203b are connected by a synchronous belt 204.

[0030] The inner surface of the synchronous belt 204 is evenly distributed with a plurality of protrusions 205 along the circumferential direction, and the outer peripheral surfaces of the first synchronous pulley 203a and the second synchronous pulley 203b are provided with grooves 206 that are adapted to the protrusions 205.

[0031] The inner cavity of the frame 1 is provided with a tensioning mechanism, which includes a connecting rod 207 slidably connected to the frame 1, a tensioning wheel 208 rotatably connected to the inner cavity of the connecting rod 207, a compression spring 209 between the connecting rod 207 and the frame 1, and the outer peripheral surface of the tensioning wheel 208 rolling contact with the outer surface of the synchronous belt 204.

[0032] Two sleeves 3 are fixedly connected to the top of the pallet 202. Each sleeve 3 has an axial through hole 301 at one end. Two air blowing pipes 302 are fixedly connected to the top of the frame 1. The axis of each air blowing pipe 302 coincides with the axis of the through hole 301, and the outer diameter of the air blowing pipe 302 is smaller than the inner diameter of the through hole 301.

[0033] The two air blowing pipes 302 are connected by an air inlet pipe 4, and the air inlet end of the air inlet pipe 4 is provided with a quick-connect air pipe connector 401.

[0034] A mounting plate 5 is fixedly connected to the inner cavity of the frame 1. A servo motor 501 is fixedly connected to the bottom of the mounting plate 5 by bolts. The output shaft of the servo motor 501 is connected to the central shaft of the first synchronous pulley 203a by a coupling.

[0035] The mold closing device includes a guide groove 6 opened on the opposite side of the frame 1. Two mold closing seats 601 are slidably connected in the guide groove 6. A split mold 602 is fixed on the opposite side of the two mold closing seats 601.

[0036] One of the split molds 602 has multiple guide pillars 7 fixedly connected to one side, and the other split mold 602 has a guide hole 701 adapted to the guide pillars 7 on one side, with the outer diameter of the guide pillars 7 and the inner diameter of the guide hole 701 in clearance fit.

[0037] Double-acting hydraulic cylinders 8 are fixedly connected to both sides of the inner cavity of the frame 1. The end of the telescopic rod of the double-acting hydraulic cylinder 8 is connected to the outer side of the mold clamping base 601 through a ball joint.

[0038] Pressure sensors are installed in the oil lines of the rod chamber and rodless chamber of the double-acting hydraulic cylinder 8, respectively.

[0039] Overall Workflow Overview

[0040] The molding machine generates a molten preform through the extrusion component 101, which is then lifted by the lifting device to prevent sagging. The preform is then clamped by the mold clamping device and blow-molded. The entire process is precisely controlled by servo motor drive, hydraulic system mold clamping, and pressure sensor feedback.

[0041] Working principle of the lifting device (core synchronous control)

[0042] Power transmission:

[0043] After the servo motor 501 is started, it drives the first synchronous pulley 203a to rotate through the coupling, and drives the second synchronous pulley 203b to rotate synchronously through the synchronous belt 204 (the inner protrusion 205 of the synchronous belt 204 meshes with the groove 206 of the synchronous pulley to eliminate transmission gap).

[0044] The two ball screws 2 rotate synchronously with the synchronous pulley, and the ball nuts 201 on their surfaces move linearly along the screw axis, driving the support plate 202 to rise and fall smoothly.

[0045] Tension compensation:

[0046] The compression spring 209 pushes the connecting rod 207 to keep the tensioning wheel 208 pressed against the outside of the synchronous belt, automatically compensating for the tension attenuation of the synchronous belt during long-term operation and ensuring transmission accuracy.

[0047] Billet support:

[0048] The sleeve 3 on the top of the pallet 202 rises and falls with the pallet, and its through hole 301 is aligned with the axis of the air blowing pipe 302 on the top of the frame to form a guide channel for the falling of the blank (the outer diameter of the air blowing pipe 302 is less than the inner diameter of the through hole 301 to avoid contact friction).

[0049] Working principle of mold closing device

[0050] Mold closing drive:

[0051] The telescopic rod of the double-acting hydraulic cylinder 8 is connected to the mold clamping base 601 via a ball joint. After pressurized oil is introduced into the rod chamber / rodless chamber of the cylinder, the mold clamping base 601 is pushed to slide along the guide groove 6 of the frame.

[0052] The two-sided split molds 602 move towards each other with the mold closing base 601 to achieve the clamping of the blank (the clamping force is controlled by the hydraulic system pressure, which can reach a maximum of 10T).

[0053] Precise positioning:

[0054] The guide post 7 of the split mold 602 on one side is inserted into the guide hole 701 of the split mold 602 on the other side. The tapered guide part at the front end of the guide post ensures quick alignment and eliminates mold closing deviation.

[0055] Pressure feedback control:

[0056] The pressure sensor monitors the pressure in the rod-side / rodless chamber of the hydraulic cylinder in real time, and the signal is transmitted to the PLC controller. When the pressure fluctuation exceeds the threshold, the proportional solenoid valve is automatically adjusted to correct the output force of the hydraulic cylinder and avoid mold overload or insufficient mold closing.

[0057] Blow molding and collaborative control

[0058] Blow molding:

[0059] Compressed air enters the air inlet pipe 4 through the quick-connect air pipe connector 401, is split to the two side air blowing pipes 302, and is blown into the interior of the blank through the through hole 301 of the support plate sleeve, where it expands and is formed into a plastic bucket in the split mold cavity.

[0060] Speed ​​matching:

[0061] The rotational speed of the servo motor 501 is linked to the parison extrusion speed of the extrusion assembly 101 (by preset parameters of the PLC). The lifting speed of the pallet 202 is matched in real time with the parison falling speed to avoid deformation of the parison due to pulling or lifting lag (e.g., the parison lifting speed of a 20L barrel is 200mm / s, with an error of ≤5% with the extrusion speed).

[0062] Key technological advantages

[0063] Synchronous drive reliability:

[0064] The combination of 204 synchronous belt, ball screw, and tensioning mechanism reduces noise compared to traditional gear transmission, eliminates the need for regular lubrication, and extends the maintenance cycle to 5000 hours.

[0065] Mold closing accuracy guarantee:

[0066] The guide post 7 guides and hydraulic cylinder ball joint connection solves the problem of uneven load when the traditional threaded rod is closed, and improves the uniformity of the plastic barrel wall thickness.

[0067] Intelligent feedback control:

[0068] The pressure sensor is linked with the PLC to achieve adaptive adjustment of the mold closing force (e.g., 5T for small-sized barrels, automatically increasing to 8T for large-sized barrels), thus reducing the defect rate.

[0069] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Additionally, in the accompanying drawings of this utility model, the fill patterns are merely for distinguishing layers and do not constitute any other limitation.

[0070] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A plastic bucket extrusion blow molding machine, comprising: Frame (1), extrusion assembly (101), lifting device and mold closing device; The feature is that the lifting device includes two ball screws (2) installed at the bottom of the inner cavity of the frame (1) by bearings, and each ball screw (2) is threaded with a ball nut (201) on its surface, and a support plate (202) is fixedly connected to the surface of the ball nut (201). One end of each of the two ball screws (2) is connected to a first synchronous pulley (203a) and a second synchronous pulley (203b), respectively. The first synchronous pulley (203a) and the second synchronous pulley (203b) are connected by a synchronous belt (204). The inner surface of the synchronous belt (204) is evenly distributed with a plurality of protrusions (205) along the circumferential direction, and the outer peripheral surfaces of the first synchronous pulley (203a) and the second synchronous pulley (203b) are provided with grooves (206) that are adapted to the protrusions (205). The inner cavity of the frame (1) is provided with a tensioning mechanism, which includes a connecting rod (207) slidably connected to the frame (1), a tensioning wheel (208) rotatably connected to the inner cavity of the connecting rod (207), a compression spring (209) between the connecting rod (207) and the frame (1), and the outer peripheral surface of the tensioning wheel (208) rolling contact with the outer surface of the synchronous belt (204).

2. The plastic bucket extrusion blow molding machine according to claim 1, characterized in that: The top of the pallet (202) is fixedly connected to two sleeves (3), and one end of each sleeve (3) is provided with an axially penetrating through hole (301). The top of the frame (1) is fixedly connected to two air blowing pipes (302), the axis of each air blowing pipe (302) coincides with the axis of the through hole (301), and the outer diameter of the air blowing pipe (302) is smaller than the inner diameter of the through hole (301).

3. The plastic bucket extrusion blow molding hollow forming machine according to claim 2, characterized in that: The two air blowing pipes (302) are connected by an air inlet pipe (4), and the air inlet end of the air inlet pipe (4) is provided with a quick-connect air pipe connector (401).

4. The plastic bucket extrusion blow molding hollow forming machine according to claim 1, characterized in that: The inner cavity of the frame (1) is fixedly connected to a mounting plate (5), and the bottom of the mounting plate (5) is fixedly connected to a servo motor (501) by bolts. The output shaft of the servo motor (501) is connected to the central shaft of the first synchronous pulley (203a) by a coupling.

5. A plastic bucket extrusion blow molding machine according to claim 1, characterized in that: The mold clamping device includes a guide groove (6) opened on the opposite side of the frame (1), and two mold clamping bases (601) are slidably connected in the guide groove (6). A split mold (602) is fixed on the opposite side of the two mold clamping bases (601).

6. A plastic bucket extrusion blow molding machine according to claim 5, characterized in that: One of the split molds (602) has a plurality of guide posts (7) fixedly connected to one side, and the other split mold (602) has a guide hole (701) adapted to the guide post (7) on one side, with the outer diameter of the guide post (7) and the inner diameter of the guide hole (701) in clearance fit.

7. A plastic bucket extrusion blow molding machine according to claim 5, characterized in that: Double-acting hydraulic cylinders (8) are fixedly connected to both sides of the inner cavity of the frame (1). The end of the telescopic rod of the double-acting hydraulic cylinder (8) is connected to the outer side of the mold clamping base (601) through a ball joint.

8. A plastic bucket extrusion blow molding machine according to claim 7, characterized in that: Pressure sensors are installed in the oil lines of the rod chamber and rodless chamber of the double-acting hydraulic cylinder (8).

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