A fast and accurate method to stack plastic containers

Abstract

A stable, fast and accurate method for stacking cups in plastic containers, characterized in that: a cup taking station, a stacking station, a transfer station and a finished product output station are sequentially arranged along the moving direction of the plastic container, and the method includes the following steps: a. taking out the plastic container and stacking it; b. two cup stacking devices exchanging positions; c. stacking the finished plastic container stack; d. delivering the finished plastic container stack. The present invention has a higher accuracy when stacking because the process of taking out the plastic container is stable and fast; because two cup stacking devices are used to continuously exchange positions, the steps of stacking the semi-finished plastic container stack and stacking the finished plastic container stack and delivering the finished plastic container stack can be performed simultaneously, which can greatly reduce the wasted time and effectively improve the work efficiency. The stacking process can be completed entirely by automated equipment; because the stacking accuracy is high and accidents are not likely to occur, the number of finished plastic container stacks obtained is accurate and does not need to be counted; it can effectively improve the work efficiency.

Description

Technical Field

[0001] The invention relates to a cup stacking method which can smoothly, quickly and accurately complete the process of taking cups, placing cups and stacking cups into a finished plastic container stack. Background Art

[0002] At present, plastic container cup making machines are generally divided into two types: one is a flip molded cup machine. After the air pressure thermoforming cup making machine automatically and quickly completes the shaping and punching, the lower mold body flips 90 degrees, and the cup bottom rod pushes the cup in the mold cavity out of the mold cavity to automatically stack and count the cups; however, the price of this equipment is particularly expensive, and due to the influence of the specifications and cavity number distance of the lateral mold cavity, the dense stacked cups, and the influence of the stacked cup guide frame, it is impossible to spot check the product quality in time. The other is a thermoforming cup making machine whose lower mold body cannot be flipped. Its upper mold body is fixed, and the lower mold body is raised and lowered. When it is lowered into place, the mold is closed, the shaping and punching are completed, and the mold is opened. When the lower mold body is in place, the cup bottom rod pushes the cup out of the mold cavity, and the high-pressure gas blows the cup out of the mold body. This air pressure thermoforming cup making machine that cannot flip the mold has similar production efficiency and cup making quality as the flip molded cup machine, but the price is one twentieth of the flip molded cup machine. Its disadvantage is that it cannot complete automatic counting and automatic cup stacking. At the same time, this cup making machine opens the mold after forming, punching and shearing, the mold bottom pushes the container out of the mold cavity, and the air pressure blows the cup out of the mold body and scatters it to the cup inspection position, and then the cup is inspected manually.

[0003] In order to solve the above problems, the commonly used cup stacking method for plastic containers is usually to use a robot to take out all the plastic containers in the mold of the molding machine at the same time, and then stack them into a long plastic container pile, and then send them out for packaging, so as to obtain the plastic container packaging we often see on the market. However, the disadvantage of this cup stacking method is that the mold of the molding machine usually has a large number of plastic containers, which are arranged in an array (such as 5 rows and 6 columns, 8 rows and 9 columns, etc.), and the action end of the robot is usually set on one side of the frame. The cup holder needs to be connected to the action end of the robot through a long arm. Therefore, the cup holder is prone to shaking during operation, which affects the accuracy of the cup taking action and easily causes the plastic container to be skewed, fall off, or unable to be taken out.

[0004] For example, a counting and stacking machine disclosed in a Chinese patent document with publication number CN103086160A and titled “Automatic High-Speed ​​Cup Picking and Counting Stacking Machine” discloses a cup stacking method and a cup stacking device. The cup picking rack is connected to the action end of the manipulator through a long arm. Therefore, the cup picking rack is prone to shaking during action, affecting the accuracy of the cup picking action, and easily causing the plastic containers to be skewed, dropped, or unable to be taken out. Moreover, the plastic containers are prone to misalignment during the stacking operation, so that the stacking fails completely, the plastic container is stuck on the cup mouth of the next plastic container, and the plastic container stack overturns. Moreover, the number and height of the plastic containers in the plastic container stack are greatly limited (i.e., the semi-finished plastic container stack). After being transferred to the packaging station, they need to be manually stacked and counted again to obtain a finished plastic container stack with a sufficient number of plastic containers before packaging. The work efficiency is low, so this technology cannot meet the needs of large-scale industrial production. Summary of the invention

[0005] The purpose of the present invention is to provide a stable, fast and accurate method for stacking plastic container cups, which can steadily and accurately take the cups and stack them in sequence. The technical solution adopted is as follows:

[0006] A stable, fast and accurate method for stacking cups of plastic containers, characterized in that a cup taking station, a stacking station, a transfer station and a finished product output station are sequentially arranged along the moving direction of the plastic container, comprising the following steps:

[0007] a. Taking out plastic containers and stacking them. The cup taking device takes out multiple plastic containers from the mold of the molding machine at the cup taking station and smoothly puts them into a cup stacking device at the stacking station to stack them, thereby obtaining multiple semi-finished plastic container stacks;

[0008] b. The two cup stacking devices exchange positions. The cup stacking device with multiple semi-finished plastic container stacks at the stacking station and the empty cup stacking device at the transfer station exchange positions with each other;

[0009] c. Stacking the finished plastic container stacks, feeding all the semi-finished plastic container stacks of the cup stacking device located at the transfer station into the transfer device in a vertical state in batches until all the semi-finished plastic container stacks are fed into the transfer device and a plurality of finished plastic container stacks are formed;

[0010] d. Send out the finished plastic container stacks, rotate the transfer device to a horizontal state, push all the finished plastic container stacks in the transfer device to the finished product output station, and then reverse the transfer device back to a vertical state.

[0011] In a preferred embodiment, in step a, all plastic containers in the mold are removed from the mold of the molding machine simultaneously, smoothly and quickly.

[0012] In a more preferred solution, in step a, the middle stable pick-up and place unit is used to move steadily and exert force on the middle of the cup-taking device, driving the cup-taking device to move steadily up and down or move linearly in the horizontal direction to complete the cup-taking and cup-placing actions. Since the middle stable pick-up and place unit moves steadily and exerts force on the middle of the cup-taking device, the cup-taking device is evenly stressed and is not easy to shake during the movement, and can maintain good stability, so that the plastic container can be well kept stable during the cup-taking and cup-placing process, and is convenient for accurate stacking.

[0013] In a preferred solution, the first track of the cup stacking device moving from the stacking station to the transfer station in step b is parallel to the second track of the cup stacking device moving from the transfer station to the stacking station. That is, one track is located above the other track (the first track is located above the second track, or the second track is located above the first track), so that the two will not interfere with each other.

[0014] A preferred solution is that the cup stacking device has multiple rows of cup stacking rack groups, each row of cup stacking rack groups has multiple cup stacking racks, and all cup stacking rack groups have the same number of cup stacking racks; in step c, the transfer device has a row of transfer cup rack groups, the transfer cup rack group has multiple transfer cup racks, and the number of transfer cup racks and the number of cup stacking racks of any row of cup stacking rack groups of the cup stacking device are the same and correspond one to one, and each transfer cup rack is located directly above the movement trajectory of the corresponding cup stacking rack; each row of cup stacking rack groups of the cup stacking device makes intermittent motion along the first trajectory and stops in sequence directly below the transfer cup rack group of the transfer device when stopping, and when a row of cup stacking rack groups stops directly below the transfer cup rack group of the transfer device, the semi-finished plastic container stacks of each cup stacking rack are respectively sent to the corresponding transfer cup rack located above.

[0015] Compared with the prior art, the beneficial effects of the present invention are that since the process of taking out the plastic containers is smooth and fast, the stacking accuracy is higher; since two cup stacking devices are used to continuously exchange positions, the steps of stacking the semi-finished products of the plastic container pile and the steps of stacking the finished products of the plastic container pile and sending them out can be performed simultaneously, which can greatly reduce the idle time and effectively improve the work efficiency, and the stacking step of the finished plastic container pile is divided into two steps: stacking the plastic containers one by one into the semi-finished products of the plastic container pile and stacking the semi-finished products of the plastic container pile one by one into the finished plastic container pile, so that the stacking process can be completed entirely by automated equipment; since the stacking accuracy is high and accidents are not prone to occur, the number of finished plastic container piles obtained is accurate and does not need to be counted; since the processing method is improved, the processing method is more reasonable and the time consumption of each step is not much different, so the work efficiency can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1is a schematic diagram of the structure of a device used in an embodiment of the present invention;

[0017] Figure 2 yes Figure 1 A schematic structural diagram of two cup stacking devices and a corresponding first reciprocating motion device in the illustrated embodiment;

[0018] Figure 3 yes Figure 1 Schematic diagram of the transfer device, the vertical pushing device, and the two cup stacking devices of the illustrated embodiment;

[0019] Figure 4 is a schematic structural diagram of a cup taking device according to an embodiment of the present invention;

[0020] Figure 5 It is a schematic structural diagram of a cup taking device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] like Figure 1 As shown, a stable, fast and accurate plastic container cup stacking method in one embodiment of the present application includes a cup taking station A, a stacking station B, a transfer station C and a finished product output station D arranged in sequence along the moving direction of the plastic container, and includes the following steps:

[0022] a. Taking out plastic containers and stacking them. The cup taking device takes out multiple plastic containers from the mold of the molding machine at the cup taking station A and puts them into a cup stacking device 3 at the stacking station B for stacking, thereby obtaining multiple semi-finished plastic container stacks;

[0023] b. The two cup stacking devices 3 exchange positions. The cup stacking device 3 with multiple semi-finished plastic container stacks at the stacking station B and the empty cup stacking device 3 at the transfer station C exchange positions with each other;

[0024] c. Stacking the finished plastic container stacks, feeding all the semi-finished plastic container stacks of the cup stacking device 3 located at the transfer station C into the transfer device 5 in a vertical state in batches until all the semi-finished plastic container stacks are fed into the transfer device 5 and a plurality of finished plastic container stacks are formed;

[0025] d. Send out the finished plastic container stacks, the transfer device 5 rotates to a horizontal state, and then pushes all the finished plastic container stacks in the transfer device 5 to the finished product output station D, and then the transfer device 5 reverses back to a vertical state. Since the process of taking out the plastic containers is smooth and fast, the stacking is more accurate.

[0026] like Figure 1-3 As shown, an optional embodiment of the present application is an apparatus used in a stable, fast and accurate method for stacking plastic containers.

[0027] like Figure 1As shown, an optional embodiment of the present application, step a is to simultaneously and smoothly and quickly remove all plastic containers in the mold from the mold of the molding machine.

[0028] like Figure 1 As shown, an optional embodiment of the present application, in the step a, the middle stable pick-up and place unit 1 is used to move steadily and apply force to the middle of the cup-taking device 2, driving the cup-taking device 2 to move steadily up and down or move linearly in the horizontal direction to complete the cup-taking and cup-placing actions. Since the middle stable pick-up and place unit 1 moves steadily and applies force to the middle of the cup-taking device 2, the cup-taking device 2 is evenly stressed and is not easy to shake during the movement, and can maintain good stability, so that the plastic container can be well kept stable during the process of taking and placing the cup, and is convenient for accurate stacking.

[0029] like Figure 1 As shown, in an optional embodiment of the present application, in step a, the middle stable pick-and-place unit 1 uses the first driving device 101 on both sides of the sliding frame to synchronously pull the two sides of the sliding frame 102 to rise and fall along the two guide rails 103. This driving method is to make the larger sliding frame 102 more evenly stressed, move more smoothly, and not easily shake.

[0030] like Figure 1 As shown, in an optional embodiment of the present application, the first driving device 101 uses a servo motor and a synchronous shaft to drive two synchronous belts to move, thereby achieving the purpose of synchronously pulling the two sides of the sliding frame 102.

[0031] like Figure 1 As shown, in an optional embodiment of the present application, in the step a, the middle stable pick-up and place unit 1 uses the second driving device 104 to push or pull the cup-taking device 2 to move linearly along the horizontal direction at the middle of the top surface of the cup-taking device 2. This driving method is to make the middle of the top surface of the cubic cup-taking device 2 bear force when the cup-taking device 2 moves in the horizontal direction, so that it is not easy to shake during movement, and it can move more smoothly.

[0032] like Figure 1 As shown, an optional embodiment of the present application, the second driving device 104 uses a servo motor to drive multiple rollers to rotate, and then all the rollers are brought into rolling contact with a slide groove that can move linearly in the horizontal direction, thereby converting the rotation into linear motion of the slide groove, and the middle part of the top surface of the cup-taking device 2 is installed on the bottom surface of the slide groove, which can prevent the cup-taking device 2 from shaking easily during movement and make it move more smoothly.

[0033] In an optional embodiment of the present application, the second driving device 104 uses a rodless cylinder to drive the cup taking device 2 to move.

[0034] In an optional embodiment of the present application, in step a, the cup stacking device 3 is vibrated below a cup stacking device 3 located at the stacking station B. This can further prevent the plastic container from getting stuck and ensure the quality of the semi-finished plastic container stack.

[0035] In an optional embodiment of the present application, in step a, a vibrator is used to vibrate the cup stacking device 3 below the cup stacking device 3 located at the stacking station B.

[0036] like Figure 1 As shown, an optional embodiment of the present application, in step a, the cup-taking device 2 includes a positioning frame 201 and a plurality of vacuum suction cups 202 mounted on the positioning frame, and the positioning frame 201 is mounted on the middle stable pick-and-place unit 1. This solution adopts a traditional vacuum suction cup 202, and when taking the cup, the vacuum suction cup 202 needs to be lowered and extended into the inner cavity of the plastic container to suck the bottom surface of the inner cavity of the plastic container, and then the middle stable pick-and-place unit 1 drives the positioning frame 201 and all vacuum suction cups 202 to rise and leave the mold.

[0037] like Figure 4 As shown, an optional embodiment of the present application, in step a, the cup-taking device 2 includes a positioning plate 203 and a plurality of negative pressure cup-taking and placing units 204 mounted on the bottom surface of the positioning plate 203, the negative pressure cup-taking and placing units 204 include a mounting base 20401, a cup-mouth sealing disc 20402, an air pipe connected to the vacuum device is opened between the top and bottom surfaces of the mounting base 20401, the top surface of the mounting base 20401 is mounted on the positioning plate 203, the cup-mouth sealing disc 20402 is mounted on the bottom surface of the negative pressure mounting base 20401, a vacuum hole 204021 is opened in the middle of the cup-mouth sealing disc 20402, and the vacuum hole 204021 is connected to the air pipe. During the process of taking and placing the cup, this suction cup type cup-taking device 2 can complete the cup-taking work without extending into the plastic container. Compared with the traditional vacuum suction cup cup-taking method, this section of the descending process and the subsequent ascending process are saved, so the work efficiency can be further improved.

[0038] like Figure 5As shown, an optional embodiment of the present application, in step a, the cup taking device 2 includes a mounting frame 205, a clamping frame 206 and a clamping frame telescopic member 207, the mounting frame 205 is mounted on the middle stable taking and placing unit 1, the clamping frame 206 is slidably arranged on the top surface of the mounting frame 205, the clamping frame telescopic member 207 is mounted on the top surface of the mounting frame 205, and the clamping frame telescopic member 207 has a telescopic end 20701, and the telescopic end 20701 is connected to the clamping frame 20 6 and moves with the clamping frame 206 on the top surface of the mounting frame 205; the mounting frame 205 is provided with a plurality of cup holes 20501, the clamping frame 206 includes a positioning frame 20601 and a plurality of clamping units 20602, the clamping units 20602 and the cup holes 20501 are of the same number and correspond one to one, and when the clamping frame 206 moves, each clamping unit 20602 cooperates with the corresponding cup hole 20501 to clamp the cup mouth of the plastic container passing through the cup hole 20501 from bottom to top. During the process of taking and placing the cup, the clamping cup taking device 2 can complete the cup taking work without extending into the plastic container, and compared with the traditional method of taking the cup by vacuum suction cup, this section of the descending process and the subsequent ascending process are saved, so the work efficiency can be further improved. Moreover, the clamping cup taking and placing mechanism of this embodiment can be applied to a wide range of plastic container cup mouth sizes (all plastic containers with cup mouth sizes smaller than the inner diameter of the cup hole 101 are applicable), and the depth of the plastic container is not limited.

[0039] like Figure 1 As shown, in an optional embodiment of the present application, in step b, the first track of the cup stacking device 3 moving from the stacking station B to the transfer station C is parallel to the second track of the cup stacking device 3 moving from the transfer station C to the stacking station B. In other words, one track is located above the other track (the first track is located above the second track, or the second track is located above the first track), so that the two will not interfere with each other. The two cup stacking devices 3 continuously and alternately move along the first track (processing) and the second track (return), and the processing on the two stations is completed in turn in relay, so the two stations will not be vacant, and each processing equipment does not need to wait for the cup stacking device 3.

[0040] like Figure 3 As shown, in an optional embodiment of the present application, the movement of the two cup stacking devices 3 in step b is achieved by different first reciprocating motion devices 4 .

[0041] like Figure 3As shown, an optional embodiment of the present application, the first reciprocating motion device 4 uses a servo motor to drive the synchronous belt to move, and a track parallel to the first track and the second track is set, and a sliding seat is set on the track, and a first cylinder is set on the sliding seat, and the cup stacking device 3 is installed on the piston shaft of the first cylinder. The synchronous belt drives the cup stacking device 3 to move smoothly along the track, and the first cylinder allows the cup stacking device 3 to change the motion track between the first track and the second track.

[0042] like Figure 1-3 As shown, an optional embodiment of the present application, the cup stacking device 3 has multiple rows of cup stacking rack groups 301, each row of cup stacking rack groups 301 has multiple cup stacking racks 3011, and the number of cup stacking racks 3011 in all cup stacking rack groups 301 is the same; in step c, the transfer device 5 has a row of transfer cup rack groups 501, the transfer cup rack group 501 has multiple transfer cup racks 5011, and the number of transfer cup racks 5011 and the number of stacking cup racks 3011 in any row of cup stacking rack groups 301 of the cup stacking device 3 are the same. The same and one-to-one correspondence, each transfer cup rack 5011 is located directly above the movement trajectory of the corresponding cup stacking rack 3011; each row of cup stacking rack groups 301 of the cup stacking device 3 makes intermittent motion along the first trajectory and stops in sequence directly below the transfer cup rack group 501 of the transfer device 5 when stopping motion; when a row of cup stacking rack groups 301 stops directly below the transfer cup rack group 501 of the transfer device 5, the semi-finished plastic container stacks of each cup stacking rack 3011 are respectively delivered to the corresponding transfer cup rack 5011 located above.

[0043] like Figure 3 As shown, in an optional embodiment of the present application, in step c, a vertical pushing device 10 is used to send the semi-finished plastic container stacks of each cup stacking rack 3011 into the corresponding transfer cup rack 5011 located above.

[0044] like Figure 1 , 3 As shown, in an optional embodiment of the present application, the transfer device 5 further includes a swing mechanism 502, and the swing mechanism 502 drives the transfer cup rack group 501 to swing between a vertical state and a horizontal state.

[0045] like Figure 1As shown, an optional embodiment of the present application, in step d, a second reciprocating motion device 6 is used to drive the second cylinder 7 to move between the transfer station C and the finished product output station D, and a lever frame 8 is installed on the piston shaft of the second cylinder 7, and the lever of the lever frame 8 extends downward; when the second cylinder 7 moves to the entrance of the transfer device 5 in a horizontal state, the piston shaft of the second cylinder 7 drives the lever frame 8 to descend until the bottom end of the lever of the lever frame 8 is inserted into the entrance of the transfer device 5, and then the second reciprocating motion device 6 drives the second cylinder 7 and the lever frame 8 to move in the opposite direction, thereby pushing all the finished plastic container stacks in the transfer device 5 to the finished product output station D, and finally the second cylinder 7 drives the lever frame 8 to rise and return to its original position.

[0046] like Figure 1 As shown, an optional embodiment of the present application is that the finished product output station D is provided with a plastic container stack finished product receiving device 9, and all the plastic container stack finished products in the transfer device 5 are pushed to the plastic container stack finished product receiving device 9 of the finished product output station D, and then these plastic container stack finished products are loaded into packaging manually or by equipment to make packaged finished products.

[0047] like Figure 1-3 As shown, the present application adopts the middle stable pick-up and placement unit 1 to move smoothly and apply force to the middle of the cup-taking device 2, so that the process of the cup-taking device 2 taking out the plastic container is smooth and fast, so the stacking accuracy is higher; two cup stacking devices 3 are used to exchange positions and relay to complete the work of the stacking station B and the transfer station C in turn, so the steps of stacking the semi-finished plastic container piles and stacking the finished plastic container piles and sending them out can be carried out simultaneously, which can greatly reduce the idle time and effectively improve the work efficiency; and the step of stacking the finished plastic container piles is divided into two steps: stacking the plastic containers one by one into the semi-finished plastic container piles and stacking the semi-finished plastic container piles one by one into the finished plastic container piles, so that the stacking process can be completed entirely by automated equipment; since the stacking accuracy is high and accidents are not likely to occur, the number of finished plastic container piles obtained is accurate and does not need to be counted; since the processing method has been improved, the processing method is more reasonable and the time consumption of each step is not much different, so the work efficiency can be effectively improved.

[0048] In addition, it should be noted that the names of the various parts of the specific embodiments described in this specification may be different, and any equivalent or simple changes made based on the structure, features and principles described in the patent concept of the present invention are included in the protection scope of the patent of the present invention. The technicians in the technical field of the present invention can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A stable, fast and accurate method for stacking plastic containers, characterized by: Along the moving direction of the plastic container, a cup taking station, a stacking station, a transfer station, and a finished product output station are sequentially arranged, including the following steps: a. Taking out plastic containers and stacking them. The cup taking device takes out multiple plastic containers from the mold of the molding machine at the cup taking station and smoothly puts them into a cup stacking device at the stacking station to stack them, thereby obtaining multiple semi-finished plastic container stacks; b. The two cup stacking devices exchange positions. The cup stacking device with multiple semi-finished plastic container stacks at the stacking station and the empty cup stacking device at the transfer station exchange positions with each other; c. Stacking the finished plastic container stacks, feeding all the semi-finished plastic container stacks of the cup stacking device located at the transfer station into the transfer device in a vertical state in batches until all the semi-finished plastic container stacks are fed into the transfer device and a plurality of finished plastic container stacks are formed; d. Send out the finished plastic container stacks, rotate the transfer device to a horizontal state, push all the finished plastic container stacks in the transfer device to the finished product output station, and then reverse the transfer device back to a vertical state; In step b, the first trajectory of the cup stacking device moving from the stacking station to the transfer station is parallel to the second trajectory of the cup stacking device moving from the transfer station to the stacking station; The movement of the two cup stacking devices in step b is achieved by different first reciprocating motion devices; The first reciprocating motion device uses a servo motor to drive the synchronous belt to move, and a track parallel to the first track and the second track is set, and a sliding seat is set on the track, and a first cylinder is set on the sliding seat, and the cup stacking device is installed on the piston shaft of the first cylinder; In step d, a second reciprocating motion device is used to drive the second cylinder to move between the transfer station and the finished product output station, and a lever frame is installed on the piston shaft of the second cylinder, and the lever of the lever frame extends downward; when the second cylinder moves to the entrance of the transfer device in a horizontal state, the piston shaft of the second cylinder drives the lever frame to descend until the bottom end of the lever of the lever frame is inserted into the entrance of the transfer device, and then the second reciprocating motion device drives the second cylinder and the lever frame to move in the opposite direction, thereby pushing all the finished plastic container stacks in the transfer device to the finished product output station, and finally the second cylinder drives the lever frame to rise and return to its original position.

2. The method for stacking plastic containers quickly and accurately as claimed in claim 1, characterized in that: In the step a, all plastic containers in the mold are taken out from the mold of the molding machine simultaneously, smoothly and quickly.

3. The method for stacking plastic containers quickly and accurately as claimed in claim 1, characterized in that: In step a, the middle stable picking and placing unit moves steadily and applies force to the middle of the cup picking device, driving the cup picking device to move up and down steadily or move linearly in the horizontal direction to complete the cup picking and placing actions.

4. The method for stacking plastic containers quickly and accurately as claimed in claim 3, characterized in that: In the step a, the middle stable pick-and-place unit uses a first driving device on both sides of the sliding frame to synchronously pull the two sides of the sliding frame to rise and fall along the two guide rails respectively.

5. The method for stacking plastic containers quickly and accurately as claimed in claim 4, characterized in that: In the step a, the middle stable picking and placing unit uses a second driving device to push or pull the cup picking device to perform linear motion along the horizontal direction in the middle of the top surface of the cup picking device.

6. The method for stacking plastic containers quickly and accurately as claimed in claim 1, characterized in that: The cup stacking device has multiple rows of cup stacking rack groups, each row of cup stacking rack groups has multiple cup stacking racks, and the number of cup stacking racks in all cup stacking rack groups is the same; in step c, the transfer device has a row of transfer cup rack groups, the transfer cup rack group has multiple transfer cup racks, and the number of transfer cup racks and the number of cup stacking racks in any row of cup stacking rack groups of the cup stacking device are the same and correspond one to one, and each transfer cup rack is located directly above the motion trajectory of the corresponding cup stacking rack; Each row of cup stacking rack groups of the cup stacking device makes intermittent motion along the first trajectory and stops in sequence directly below the transfer cup rack group of the transfer device when the motion stops. When a row of cup stacking rack groups stops directly below the transfer cup rack group of the transfer device, the semi-finished products of the plastic container stacks of each cup stacking rack are respectively sent into the corresponding transfer cup rack located above.

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