A rapid forming and demolding device for paper tableware

Abstract

The utility model provides a kind of paper dinner plate rapid forming demolding device, belong to demolding device technical field, this paper dinner plate rapid forming demolding device includes: upper die, for forming dinner plate;Lower die, it is oppositely arranged with the upper die, for supporting dinner plate;Symmetrically arranged elastic wedge-shaped slide rail group, located the lower die below, the elastic wedge-shaped slide rail group includes spring steel sheet and low friction sliding block, one end of the spring steel sheet is fixed, other end is connected with the low friction sliding block, the low friction sliding block has gradually increasing angle inclined plane, the inclined plane is towards dinner plate bottom edge;Wherein, when the upper die is down, the low friction sliding block is laterally slid into dinner plate bottom edge under the elastic force of the spring steel sheet, forms progressive multi-point support stripping, solves the core problem that traditional vertical ejector pin pushes locally to paper tray, causes stress concentration, easily torn and broken.

Description

Technical Field

[0001] This utility model belongs to the technical field of demolding devices, specifically, it relates to a rapid prototyping and demolding device for paper plates. Background Technology

[0002] Paper plates are rapidly replacing plastic plates in the disposable tableware market due to their biodegradability, recyclability, and printability. Wet thermoforming is currently the most common method for manufacturing paper plates: pulp is initially shaped on a die under vacuum, then the upper and lower dies are closed, and the plates are dehydrated, dried, and calendered through hot pressing to achieve sufficient stiffness and surface quality. After forming, the upper die is raised, but the plate remains wrapped around or tightly adhered to the lower die, requiring a demolding mechanism to remove it smoothly. The demolding process directly determines whether the finished product can proceed intact to subsequent sterilization, stacking, and packaging processes, and also directly affects production cycle time and raw material utilization.

[0003] Current technology generally employs vertical ejection demolding: multiple ejector pins are arranged at the bottom of the mold, and the plate is lifted vertically as a whole using the force of cylinders, cams, or springs, and then removed manually or by a robotic arm. This method is simple in structure and easy to manufacture, but it has revealed obvious drawbacks in actual operation. First, the contact area between the ejector pins and the paper plate is small, and the pressure is high, making it easy to puncture or leave pinholes when the wet paper fibers are not fully cured, creating a risk of leakage. Second, the synchronization error of multiple ejector pins can lead to uneven force distribution, causing thin-walled parts to tear first, resulting in gaps or cracks. Third, when the ejector pins reset, they can easily bring a small amount of paper scraps back into the mold cavity, which accumulates and affects the vacuum suction effect of the next mold, requiring frequent machine stops for cleaning. In addition, for complex plates with deep cavities, rolled edges, or reinforcing ribs, it is difficult to arrange ejector pins at all key support points, often resulting in local sticking to the mold, requiring manual tapping to assist demolding, which is labor-intensive and noisy. Utility Model Content

[0004] In view of this, the present invention provides a rapid forming and demolding device for paper plates, which solves the core problem of stress concentration and easy tearing and damage caused by the local pushing of paper plates by traditional vertical pushers.

[0005] This utility model is implemented as follows:

[0006] This utility model provides a rapid forming and demolding device for paper dinner plates, comprising:

[0007] The upper mold is used to shape the dinner plate;

[0008] The lower mold, positioned opposite the upper mold, is used to support the plate;

[0009] A symmetrically arranged elastic wedge slide rail assembly is located below the lower mold. The elastic wedge slide rail assembly includes a spring steel sheet and a low-friction slider. One end of the spring steel sheet is fixed, and the other end is connected to the low-friction slider. The low-friction slider has a gradually rising angle slope, and the slope faces the bottom edge of the plate.

[0010] When the upper mold moves downward, the low-friction slider slides laterally into the bottom edge of the plate under the elastic force of the spring steel sheet, forming a progressive multi-point support peeling.

[0011] The technical effects of the paper plate rapid forming and demolding device provided by this utility model are as follows: by symmetrically arranging elastic wedge slide rails below the lower mold, the low-friction slider automatically slides laterally into the bottom edge of the plate when the upper mold moves downward, forming a progressive multi-point support peeling, replacing the traditional vertical ejector pin, fundamentally eliminating local stress concentration, and achieving gentle demolding with no ejector pins and zero tearing.

[0012] Based on the above technical solution, the paper plate rapid forming and demolding device of this utility model can be further improved as follows:

[0013] The elastic wedge-shaped slide rails are symmetrically arranged on both sides of the lower mold, and the inclined surface of the low-friction slider contacts the bottom edge of the plate to form a line contact support.

[0014] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the elastic wedge slide rails are symmetrically placed on both sides of the lower mold and the inclined surface forms a line contact with the bottom edge of the plate, so that the peeling force is evenly distributed along the circumference, preventing edge gaps caused by unilateral pulling and ensuring the integrity of the plate outline.

[0015] Furthermore, the spring steel sheet is curved in an arc shape, the low-friction slider is located at the free end of the spring steel sheet, and the fixed end of the spring steel sheet is connected to the device base.

[0016] The beneficial effects of adopting the above-mentioned improved scheme are as follows: an arc-shaped bent spring steel sheet is used and a low-friction slider is set at the free end. The fixed end of the steel sheet is connected to the base. The elastic potential energy stored by the arc deformation is used to drive the slider to slide laterally. No additional power is required. The structure is simple and the response is fast. At the same time, the arc bending provides a larger elastic stroke, which can adapt to the slight height difference of pulp of different thicknesses.

[0017] Furthermore, the inclined surface of the low-friction slider is a smooth curved surface, and the helix angle of the inclined surface gradually increases along the sliding direction.

[0018] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: by setting the inclined surface of the low-friction slider as a smooth curved surface and gradually increasing the rise angle, the direction of the supporting force of the slider on the bottom of the plate gradually changes from approximately horizontal to obliquely upward during the sliding process, the peeling action is smooth and continuous, avoiding sudden impact and reducing paper fiber damage.

[0019] Furthermore, the lower mold has a recess that matches the shape of the plate, and the elastic wedge-shaped slide rail assembly is located on the outside and below the recess.

[0020] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the elastic wedge slide rail group is arranged on the outside and below the recessed part of the lower mold, so that the slider acts directly on the lower part of the most vulnerable flange area of ​​the plate. The peeling point is close to the corner with the strongest adhesion. By using the lever principle, the edge is first pried loose in the least effort, and then the whole is lifted up. The demolding is smooth and the overall height of the mold is reduced.

[0021] Furthermore, a guide mechanism is provided between the upper mold and the lower mold to guide the vertical movement of the upper mold.

[0022] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: setting a guide mechanism between the upper and lower molds guides the upper mold to move strictly vertically, preventing horizontal deviation during the downward movement from causing misalignment between the wedge slider and the plate, ensuring accurate repeatability of the peeling point position each time, and improving the reliability of the device operation.

[0023] Furthermore, the number of elastic wedge-shaped slide rail assemblies is two, which are respectively arranged on opposite sides of the lower mold.

[0024] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: by arranging two sets of elastic wedge-shaped slide rails in opposite directions, a synchronous support of more than four points is formed, so that each side of the round or polygonal plate is subjected to peeling force at the same time, eliminating torsional deformation caused by the sequential application of force and keeping the plate flat.

[0025] Furthermore, the low-friction slider is made of a wear-resistant material, and the inclined surface has self-lubricating properties.

[0026] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the low-friction slider is made of wear-resistant and self-lubricating material, which maintains the integrity of the inclined surface shape and reduces the coefficient of friction during long-term high-frequency sliding, reduces heat and dust accumulation, extends the maintenance cycle, and ensures the stability of continuous production.

[0027] Furthermore, the thickness of the spring steel sheet gradually varies along its length to provide a gradual elastic force.

[0028] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the thickness of the spring steel sheet gradually changes along the length direction, so that the stiffness of the fixed end is large and the stiffness of the free end is small, providing sufficient support force in the early stage of demolding, and the elastic force rises gently as the deformation increases in the later stage, avoiding the instantaneous excessive thrust from breaking through the wet paper tray, and realizing elastic self-adaptation.

[0029] Furthermore, a gap is provided between the elastic wedge-shaped slide rail assembly and the lower mold to avoid interfering with the vertical movement of the lower mold.

[0030] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the gap between the elastic wedge slide rail assembly and the lower mold ensures that the slider is not interfered with when sliding laterally, and allows the lower mold to make a slight clearance at the moment of mold closing, preventing rigid collision. The whole device operates smoothly, has low noise, and is easy to disassemble and maintain.

[0031] Compared with existing technologies, the beneficial effects of the rapid prototyping and demolding device for paper plates provided by this utility model are as follows: This utility model fundamentally changes the way the peeling force is applied by symmetrically arranging elastic wedge-shaped slide rails below the lower mold, transforming the traditional "vertical ejection" into "progressive lateral lifting". During the mold closing stage, the wedge-shaped slide rails are in a retracted state, not interfering with the pulp filling and hot pressing; when the upper mold begins to rise, the spring steel sheet releases its elastic potential energy, pushing the low-friction slider to slide laterally along the inclined surface into the bottom edge of the plate, forming a continuous, multi-point, line-contact support band. The peeling force is dispersed to the thickest flanged area of ​​the plate, avoiding local stress concentration, and preventing the paper fibers from breaking due to point loads. As the angle of the slider's inclined surface gradually increases, the direction of the lifting force gradually changes from horizontal to obliquely upward. The plate separates from the lower mold in a flexible bending state. The entire process is smooth, impact-free, and noiseless, completely eliminating quality defects such as ejector pin holes, cracks, and missing edges. The curved structure of the spring steel sheet provides ample elastic stroke, allowing for adaptive support of plates of varying thicknesses, depths, and rim shapes. This enables multi-specification co-production without replacing any parts, significantly reducing changeover downtime. The slider uses wear-resistant, self-lubricating materials, maintaining low friction and low dust levels even during extended operation, significantly extending the mold cavity cleaning cycle. The guiding mechanism ensures strictly vertical movement of the upper mold, and the pre-reserved gap between the wedge-shaped slide rail and the lower mold prevents rigid collisions. The entire machine operates smoothly and reliably, reducing maintenance workload. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 A separation example diagram of a rapid prototyping and demolding device for paper dinner plates;

[0034] Figure 2 A bottom view showing the separation of a rapid prototyping and demolding device for paper plates;

[0035] Figure 3 A combined example diagram of a rapid prototyping and demolding device for paper dinner plates;

[0036] The attached diagram lists the components represented by each number as follows:

[0037] 10. Upper mold; 20. Lower mold; 30. Elastic wedge slide rail assembly; 31. Spring steel sheet; 32. Low friction slider. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0039] like Figures 1-3 The image shown is an example diagram of a rapid prototyping and demolding device for paper plates provided by this utility model, comprising:

[0040] Upper mold 10 is used to shape the dinner plate;

[0041] The lower mold 20 is positioned opposite the upper mold 10 and is used to support the dinner plate;

[0042] The symmetrically arranged elastic wedge slide rail assembly 30 is located below the lower mold 20. The elastic wedge slide rail assembly 30 includes a spring steel sheet 31 and a low friction slider 32. One end of the spring steel sheet 31 is fixed and the other end is connected to the low friction slider 32. The low friction slider 32 has a gradually rising angle slope, and the slope faces the bottom edge of the plate.

[0043] When the upper mold 10 moves downward, the low-friction slider 32 slides laterally into the bottom edge of the plate under the elastic force of the spring steel sheet 31, forming a progressive multi-point support peeling.

[0044] In the above technical solution, the elastic wedge slide rail group 30 is symmetrically arranged on both sides of the lower mold 20, and the inclined surface of the low friction slider 32 contacts the bottom edge of the plate to form a line contact support.

[0045] Furthermore, in the above technical solution, the spring steel sheet 31 is curved in an arc shape, the low-friction slider 32 is located at the free end of the spring steel sheet 31, and the fixed end of the spring steel sheet 31 is connected to the device base.

[0046] Furthermore, in the above technical solution, the inclined surface of the low-friction slider 32 is a smooth curved surface, and the helix angle of the inclined surface gradually increases along the sliding direction.

[0047] Furthermore, in the above technical solution, the lower mold 20 has a recessed portion that matches the shape of the plate, and the elastic wedge-shaped slide rail assembly 30 is located on the lower outer side of the recessed portion.

[0048] Furthermore, in the above technical solution, a guide mechanism is provided between the upper mold 10 and the lower mold 20 to guide the vertical movement of the upper mold 10.

[0049] The guiding mechanism consists of cylindrical guide rods fixed at the four corners of the upper mold and extending downwards, and oil-free lubricated copper sleeves fixed at the four corners of the lower mold or on the frame. The guide rods and copper sleeves are clearance fits with a clearance of 0.05mm to 0.15mm. The lower end of the guide rod is provided with a stop boss to limit the maximum downward stroke of the upper mold and prevent the guide rods from disengaging from the copper sleeves.

[0050] Furthermore, in the above technical solution, there are two sets of elastic wedge slide rails 30, which are respectively set on opposite sides of the lower mold 20.

[0051] Furthermore, in the above technical solution, the low-friction slider 32 is made of wear-resistant material, and the inclined surface has self-lubricating properties.

[0052] Material examples: The wear-resistant matrix uses polyetheretherketone (PEEK) or polyoxymethylene (POM), with a layer of polytetrafluoroethylene (PTFE) micro powder filling layer embedded or co-injected on the inclined surface, with a thickness of 0.2mm to 0.5mm, to form a self-lubricating working surface; alternatively, an integrally sintered oil-filled nylon 6 can be used for one-time molding, which also has self-lubricating properties.

[0053] Furthermore, in the above technical solution, the thickness of the spring steel sheet 31 gradually changes along the length direction to provide a gradual elastic force.

[0054] The spring steel sheet maintains a constant thickness for one-third of its length from the fixed end, and then gradually thins towards the free end in a linear or quadratic curve, with the thinning rate being 20% ​​to 40% of the original thickness. This reduces the stiffness of the free end and increases its deformation capacity, thereby providing a gradual elastic force under the same load, adapting to the demolding requirements of pulp plates of different thicknesses.

[0055] Furthermore, in the above technical solution, a gap is provided between the elastic wedge slide rail assembly 30 and the lower mold 20 to avoid interfering with the vertical movement of the lower mold 20.

[0056] The low-friction slider of the elastic wedge slide rail assembly maintains a static gap of 0.5mm to 2mm between the top surface of the slider and the bottom surface of the lower mold. This gap can be reduced to 0.1mm to 0.3mm when the upper mold descends to the lowest point, which ensures that the slider can slide laterally into the bottom of the plate and avoids rigid collision or jamming with the lower mold.

[0057] Example 1: The rotary four-station paper tray forming machine adopts the elastic wedge-shaped slide rail synchronous demolding device described in this utility model. A horizontal turntable with intermittent rotation is arranged in the center of the frame, with the lower mold fixed at the four corners of the turntable. The upper mold is connected to the top thermostatic cylinder via guide rods, which cooperate with oil-free copper sleeves embedded in the frame to form a strictly vertical guiding mechanism. The elastic wedge-shaped slide rail assembly is installed on the frame crossbeam directly below the lower mold: one end of a spring steel sheet is fixed to the crossbeam with a pressure plate, and the other end is hinged to a low-friction slider via a pin. A linear wear-resistant strip is embedded in the bottom of the slider, allowing it to slide laterally on the stainless steel guide rails on the surface of the crossbeam. The top surface of the slider is machined with a gradually increasing angle slope, with a gap of a few tenths of a millimeter between the highest point of the slope and the bottom surface of the lower mold, ensuring that the slider is pushed back by the lower mold during mold closing without interfering with pulp filling.

[0058] Workflow and Applicable Scenarios: After pulp injection, the hot press cylinder drives the upper die downwards, while the lower die remains stationary with the turntable. The bottom surface of the lower die presses against the top surface of the slider, compressing the spring steel sheet. The slider retracts to its limit position, and the inclined surface completely leaves the plate area. After hot pressing, the upper die rises, the lower die loses pressure, the spring steel sheet releases, and the slider slides towards the center. The inclined surface gradually lifts the plate from the outside in, causing it to flip. Multi-point line contact ensures even distribution of peeling force, allowing the wet paper plate to detach completely from the lower die without ejector pins. It is then picked up by the receiving robot on the outside of the turntable. This embodiment is suitable for high-speed production of round plates with large diameters and neatly rolled edges. The turntable has a stable cycle time, the slider requires no additional power, and maintenance only requires periodic wiping of the guide rails. It is suitable for continuous operation on long shifts in the food industry.

[0059] Example 2: The chain-type flexible deep-cavity dinner plate production line adopts the elastic wedge-shaped slide rail synchronous demolding device described in this utility model. Synchronous chains are arranged on both sides of the frame. The lower mold is suspended below the chain through a hinged seat and can move horizontally with the chain. The upper mold is fixed in a portal frame, and linear bearings are set on the inner side of the frame columns as a guiding mechanism. The elastic wedge-shaped slide rail assembly is installed on a fixed base plate below the chain, and the base plate is parallel to the synchronous section of the chain. The fixed end of the spring steel sheet is locked to the base plate with a clamp, and the free end is connected to a low-friction slider. The bottom of the slider is embedded with a needle roller guide rail, resulting in extremely low lateral movement resistance. The slider's inclined surface width is reduced, and the initial rise angle is gentler to adapt to the high sidewalls of the deep-cavity dinner plate.

[0060] Workflow and Applicable Scenarios: The lower mold, carrying wet pulp, is fed into the hot pressing frame by a chain. The upper mold descends and closes, with the bottom surface of the lower mold pressing the slider back. After hot pressing, the upper mold rises, the chain continues to advance, and the lower mold leaves the hot pressing area. At the moment of departure, a spring steel plate pushes the slider into the bottom edge of the deep cavity. The gradually tapered surface first loosens the sidewalls and then lifts and flips the edge. The deep cavity tray falls smoothly onto the conveyor belt below without impact or ejector pins. This embodiment is suitable for square or oval trays with large depth and reinforced sidewalls. The flexible chain arrangement allows for easy addition or removal of workstations, and the slider and needle roller guide rails are dust-resistant, making it suitable for rapid switching between multiple varieties and small to medium batch orders.

[0061] Specifically, the principle of this utility model is as follows: the core of the device lies in the coupling of the "elastic wedge-shaped slide rail assembly" and the "mold opening and closing motion". One end of the spring steel sheet is fixed to the frame, and the other end is connected to the low-friction slider. The steel sheet is pre-bent into an arc shape and stores elastic deformation energy. A small gap is maintained between the bottom surface of the lower mold and the top surface of the slider, allowing the slider to freely extend and retract in the horizontal direction. When the mold is closed, the upper mold moves downward and presses against the lower mold. The bottom surface of the lower mold pushes the slider back to its retracted position, and the spring steel sheet is further compressed. At this time, the inclined surface of the slider is completely separated from the plate area, and the pulp can be smoothly filled and hot-pressed. After molding is completed, the upper mold is raised, the lower mold loses pressure, the spring steel sheet rebounds, and pushes the slider to slide along the horizontal guide rail towards the center of the mold cavity. The gradually increasing angle inclined surface at the front end of the slider first contacts the lower edge of the plate flange. As it continues to slide in, the angle of the inclined surface gradually increases, generating an upward lifting force, and the edge of the plate is pried up simultaneously at multiple points. Because the lifting force is evenly distributed circumferentially and the point of application is located in the thickest flanged area, the shear and tensile stresses borne by the paper fibers are far lower than their wet strength, thus preventing tearing. When the slider reaches its maximum extension position, the plate is completely detached from the lower mold and falls onto the slider's inclined surface solely by its own weight, then is removed manually or by a conveyor belt. When the upper mold descends again, the lower mold re-presses the slider to retract, the mechanism automatically resets, and enters the next cycle. The guiding mechanism ensures the verticality of the upper mold and prevents misalignment between the slider and the plate through the clearance fit between the guide rod and the copper sleeve. The self-lubricating properties of the slider material and the gradual stiffness of the steel sheet together ensure the stability and smoothness of long-cycle operation, achieving pinless, impact-free, and self-adaptive continuous demolding.

Claims

1. A rapid forming and demolding device for paper plates, characterized in that, include: The upper mold is used to shape the dinner plate; The lower mold, positioned opposite the upper mold, is used to support the plate; A symmetrically arranged elastic wedge slide rail assembly is located below the lower mold. The elastic wedge slide rail assembly includes a spring steel sheet and a low-friction slider. One end of the spring steel sheet is fixed, and the other end is connected to the low-friction slider. The low-friction slider has a gradually rising angle slope, and the slope faces the bottom edge of the plate. When the upper mold moves downward, the low-friction slider slides laterally into the bottom edge of the plate under the elastic force of the spring steel sheet, forming a progressive multi-point support peeling.

2. The rapid forming and demolding device for paper plates according to claim 1, characterized in that, The elastic wedge-shaped slide rails are symmetrically arranged on both sides of the lower mold, and the inclined surface of the low-friction slider contacts the bottom edge of the plate to form a line contact support.

3. The rapid forming and demolding device for paper plates according to claim 2, characterized in that, The spring steel sheet is curved in an arc shape, the low-friction slider is located at the free end of the spring steel sheet, and the fixed end of the spring steel sheet is connected to the device base.

4. The rapid forming and demolding device for paper plates according to claim 3, characterized in that, The inclined surface of the low-friction slider is a smooth curved surface, and the helix angle of the inclined surface gradually increases along the sliding direction.

5. The rapid forming and demolding device for paper plates according to claim 4, characterized in that, The lower mold has a recess that matches the shape of the plate, and the elastic wedge-shaped slide rail assembly is located on the outside and below the recess.

6. The rapid forming and demolding device for paper plates according to claim 5, characterized in that, A guide mechanism is provided between the upper mold and the lower mold to guide the vertical movement of the upper mold.

7. A rapid forming and demolding device for paper plates according to claim 6, characterized in that, The number of elastic wedge-shaped slide rails is two, which are respectively set on opposite sides of the lower mold.

8. The rapid forming and demolding device for paper plates according to claim 7, characterized in that, The low-friction slider is made of wear-resistant material, and the inclined surface has self-lubricating properties.

9. A rapid forming and demolding device for paper plates according to claim 8, characterized in that, The thickness of the spring steel sheet gradually changes along its length to provide a gradual elastic force.

10. A rapid forming and demolding device for paper plates according to claim 9, characterized in that, A gap is provided between the elastic wedge-shaped slide rail assembly and the lower mold to avoid interfering with the vertical movement of the lower mold.

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