Forming Structure for Internal Snap Ring of Pulp Molded Cup Lid

BACKGROUND OF THE INVENTION

The present invention is generally directed to a forming structure for the internal snap ring of a pulp molded cup lid, and more particularly to a forming structure comprising a pulp suction mold which absorbs a layer of pulp and sends it to a hot press upper mold for clamping and squeezing to shape the layer of pulp into a primary blank, meanwhile producing an internal snap ring part on the primary blank.

DESCRIPTION OF THE RELATED ART

In consideration of the hazard of plastic products to the environment, pulp molding products are developed and have become popular. Paper fiber materials and/or plant fiber materials are mixed to form a pulp material. Then, a pulp suction mold is used to suck the pulp to produce a “pulp layer”. The “pulp layer” undergoes squeezing and shaping to from a “primary blank”. Then, the “primary blank” undergoes hot pressing and shaping to form a “pulp molding product”. Pulp molding products can be easily recycled for repeated manufacturing and can therefore meet the demand of energy saving and carbon reduction. They are quickly accepted in the industrial and commercial sector and are welcomed by the public. At present, in a global perspective, as numerous drinks (such as hot coffee, hot tea, etc.) are taken out every day, disposable pulp molded cups and pulp molded cup lids have become a big concern.

A prior-art pulp molded cup lid 1 is shown in FIGS. 1˜3. It has a lid top 11. The lid top 11 has a drinking mouth 111 for drinking the liquid inside the cup body. The structure of the lid top 11 can have various styles. However, as the various structures of the lid top 11 has nothing to do with the present invention, the possible structures on the top surface 11 are not described herein. The periphery of the lid top 11 is curved downward to form an upper surround wall 12. The bottom edge of the upper surround wall 12 expands outward and is then curved downward and slightly recessed to form an external covering edge 13. The bottom edge of the external covering edge 13 is firstly recessed and then expanded in the opposite direction to from a concave arc 14. Then, the bottom edge of the concave arc 14 is deflected outward to form a lifting wall 15.

In practice, the pulp molded cup lid 1 is used to cover the lip of a corresponding cup body 2. The using state is shown in FIG. 3. As the outer ring of the lip of the cup body 2 is a convex edge 21, due to the blocking of this convex edge 21, initially it cannot be completely covered. Firstly, the external covering edge 13 on one side of the pulp molded cup lid 1 must be covered on the convex edge 21 at the corresponding position on the cup body 2. Then, under a force, the remaining external covering edge 13 is slightly expanded outward and then recovered to forcibly pass the remaining convex edge 21, so that the external covering edge 13 can tightly cover the whole convex edge 21 of the cup body 2. Meanwhile, as the concave arc 14 supports the outside bottom edge of the convex edge 21 in a tilted manner, it is difficult to flip up the pulp molded cup lid 1 after it is covered. Hence, the coverage between the external covering edge 13 and the convex edge 21 is very stable

As can be known from FIG. 3, the prior-art pulp molded cup lid 1 must be formed with an external covering edge 13 and a concave arc 14 to tightly cover the convex edge 21 on the lip of the cup body 2. However, the pulp molded cup lid 1 must undergo a second operation to form the external covering edge 13 and the concave arc 14. The first operation is to produce a “preliminary product of the pulp molded cup lid” through pulp suction, squeezing, and hot pressing procedures. The “preliminary product of the pulp molded cup lid” is as shown in FIG. 4. The top surface 11, the upper surround wall 12, the upper part of the external covering edge 13 and the lifting wall 15 are completely formed. However, the lower part of the external covering edge 13 and the concave arc 14 are not seen. Therefore, a second operation (processing) is required to form the lower part of the external covering edge 13 and the concave arc 14 as shown in FIGS. 2 and 3. The reason that the prior-art pulp molded cup lid 1 must undergo a second operation to completely form the lower part of the external covering edge 13 and the concave arc 14 is the directional consideration and limitation of the pulp suction mold during the demolding process. The continuous reverse curving on the lower part of the external covering edge 13 and the concave arc 14 cannot be produced at the same time. Therefore, the upper part of the external covering edge 13 and the lifting wall 15 must be formed at first, and then, through a second operation (processing), the lower part of the external covering edge 13 and the concave arc 14 are completely formed.

Conventionally, the first operation forms the top surface, the upper surround wall, the upper part of the external covering edge and the lifting wall. Then, through a second operation (processing), the lower part of the external covering edge and the concave arc are formed. TWI430923 and CNZL200910157668.6 titled “Method for producing the snap groove on the plant fiber pulp molded cup lid” is an example. It uses a forming bar coupled with a slide block to support the surface of the pulp molded cup lid. Internally, a ring-shaped concave groove on an inner mold is used to form the lower part of the external covering edge and the concave arc (the name is “snap groove” in the patent). Then, the slide block is pushed inward from outside, so that the surface of the pulp molded cup lid is deformed along with the contour of the forming bar and is shrunk into the receiving groove of the inner mold, thus forming a ring-shaped “snap groove” (equivalent to the lower part of the external covering edge and the concave arc).

Moreover, there are other prior-art patents that use a first operation to form the top surface, the upper surround wall, the concave arc and the lifting wall. Then, a second operation (processing) is used to form the external covering edge. TWI542755 and CNZL201410151021.3 patent titled “Manufacturing method and finished product of pulp molded cup lid with external covering edge” is an example. It uses a slide block on an outer mold that moves on the outside surface to form the external covering edge, and the center part of an inner mold holds a forming mold that can move transversely. The forming mold moves forward to squeeze the internal surface on the pulp molded cup lid outward to form the external covering edge, so that it is deformed and formed into a ring-shaped external covering edge.

Later, there are patents like TW 1730350 and CN ZL201921023649.X, which also use a first operation to form the top surface, the upper surround wall, the upper part of the external covering edge and the lifting wall. Then, a second operation (processing) is used to form the lower part of the external covering edge and the concave arc. In the second operation (processing), a rubber ring is used. The rubber ring is an elastic body. The rubber ring is placed on the bottom of an upper mold. Through a pushing force, the upper mold part presses the rubber ring outside the part to form the concave arc. Thus, the concave arc is produced through the pushing force.

When implementing the above prior-art patents, a mold is required for the second operation (processing), and a complete external covering edge and concave arc cannot be produced without the second operation (processing) Therefore, the manufacturing cost is high and the manufacturing process is complicated. This is a problem that calls for improvement.

SUMMARY OF THE INVENTION

In view of the above requirements, the inventor of the present invention has carried out in-depth research and development and made numerous improvements in an attempt to provide a forming structure for the internal snap ring of a pulp molded cup lid. Characteristically, when manufacturing the pulp molded cup lid, the pulp suction mold sucks the pulp layer and sends it into the hot press upper mold for clamping and squeezing to shape the pulp layer into a primary blank, meanwhile producing an internal snap ring part on the primary blank. After subsequent hot pressing and shaping, the finished product of the pulp molded cup lid will have an integral internal snap ring part. Thus, it requires neither a second operation (processing), nor the preparation of a mold for the second operation (processing), and can therefore reduce manufacturing cost and time. The present invention has been successfully developed from the above creative idea after a long-term endeavor.

Therefore, it is a primary object of the present invention to provide a forming structure for the internal snap ring of a pulp molded cup lid that can save manufacturing cost and time. It is another primary object of the present invention to provide a forming structure for the internal snap ring of a pulp molded cup lid characterized in that, when manufacturing the pulp molded cup lid, the pulp suction mold sucks the pulp layer and sends it to the hot press upper mold for clamping and squeezing to shape the pulp layer into a primary blank, meanwhile forming an internal snap ring part on the primary blank.

To achieve the above-mentioned object, the present invention provides a forming structure for the internal snap ring of a pulp molded cup lid, wherein said pulp molded cup lid is formed by an automatic forming machine for manufacturing pulp molding products, the automatic forming machine for manufacturing pulp molding products has a pulp sucking and forming zone and a hot press shaping zone, the pulp sucking and forming zone is provided with a pulp box and a pulp suction mold in a working space, the pulp box is filled with pulp, the pulp suction mold can rise and fall inside the working space, the hot press shaping zone is provided with a hot press upper mold and a hot press lower mold inside a working space, the hot press upper mold is provided at an upper position inside the working space, and can be pushed to move transversely, the mold surface of the hot press upper mold faces downward, the hot press lower mold is provided beneath the hot press upper mold, and can be pushed to move upward and downward, the surface of the hot press lower mold faces upward, the pulp suction mold sucks pulp from inside the pulp box to form a pulp layer, and moves upward while sucking the pulp layer to leave the pulp box, the hot press upper mold moves toward the middle position and stops above the pulp suction mold, then, the pulp suction mold moves upward to clamp with the hot press upper mold to squeeze the pulp layer, so that the pulp layer is hardened and formed into a primary blank, then, the pulp suction mold leaves the primary blank and moves downward, the hot press upper mold sucks the primary blank to move transversely to reset, then, the hot press lower mold moves upward to clamp with the hot press upper mold to press and shape the primary blank, so that the primary blank is hardened and formed into a pulp molded cup lid, characteristically, the outer edge on the lateral surface of the hot press upper mold is configured with a ring groove, when the pulp suction mold rises and clamps with the hot press upper mold to squeeze the pulp layer, due to the squeezing, part of the pulp will enter the groove and is left there, so that the pulp layer will produce an integral internal snap ring, together with the pulp layer, the internal snap ring is squeezed and formed into part of the primary blank, and after hot pressing and shaping, it becomes part of the pulp molded cup lid.

Based on the above structure, comparing to the prior art, the present invention neither requires a second operation (processing), nor a mold to be prepared for the second operation (processing), and can therefore reduce manufacturing cost and time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the prior-art pulp molded cup lid.

FIG. 2 is a lateral view of the prior-art pulp molded cup lid.

FIG. 3 is a sectional view of the prior-art pulp molded cup lid in use when covering on the lip of the cup body.

FIG. 4 is a sectional view of the prior-art pulp molded cup lid before the concave arc is formed.

FIG. 5 is a structural view of an automatic forming machine for manufacturing pulp molding products.

FIG. 6 is a sectional view of the pulp suction mold in the present invention sucking a pulp layer.

FIG. 7 is a structural view of the hot press upper mold disclosed in the present invention.

FIG. 8 is a sectional view showing the pulp suction mold and the hot press upper mold in the present invention clamping each other to squeeze the pulp layer to form a primary blank while producing an internal snap ring.

FIG. 9 is a sectional view of the hot press upper mold in the present invention sucking a primary blank and of the internal snap ring.

FIG. 10 is a structural view of the hot press lower mold disclosed in the present invention.

FIG. 11 is a sectional view of the hot press lower mold and the hot press upper mold in the present invention clamping each other to press the primary blank and shape it into a pulp molded cup lid and an internal snap ring.

FIG. 12 is a sectional view of the hot press lower mold in the present invention sucking a pulp molded cup lid (including the internal snap ring).

FIG. 13 is a sectional view showing the pulp molded cup lid (including the internal snap ring) in use, covering the cup body lip.

REFERENCE NUMERALS IN DRAWING FIGS

- 1 Pulp molded cup lid
- 11 Lid top
- 111 Drinking mouth
- 12 Upper surround wall
- 13 External covering edge
- 14 Concave arc
- 15 Lifting wall
- 2 Cup body
- 21 Convex edge
- 3 Automatic forming machine for pulp molding product
- 30 Pulp suction forming zone
- 31 Working space
- 32 Pulp box
- 33 Pulp suction mold
- 33A Model
- 40 Hot pressing shaping zone
- 40L Left hot pressing shaping zone
- 40R Right hot pressing shaping zone
- 41 Working space
- 42 Hot pressing upper mold
- 42A Model
- 42B Groove
- 43 Hot pressing lower mold
- 43A Model
- 5A Pulp layer
- 5
  a Internal snap ring
- 5B Primary blank
- 5C Pulped mold cup lid

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Before explaining the structural and functional details of the forming structure for the internal snap ring of a pulp molded cup lid disclosed in the present invention, we shall firstly look into the overall structure and function of a general automatic forming machine for manufacturing pulp molding products.

An automatic forming machine for manufacturing pulp molding products 3 is disclosed in FIG. 5. Its structure is divided into a pulp suction forming zone 30 located in the middle and a hot press shaping zone 40 located on the left and right sides of the pulp suction forming zone 30. To facilitate explanation, it is further divided into a left hot press shaping zone 40L and a right hot press shaping zone 40R. Inside a working space 31, the pulp suction forming zone 30 is provided with a pulp box 32 and a pulp suction mold 33, wherein, the pulp box 32 is fixed inside the working space 31. The pulp box 32 is filled with pulp, with its top side open. The pulp suction mold 33 is sunk into the pulp box 32. In the initial (reset) state, the mold surface of the pulp suction mold 33 is lower than the pulp surface of the pulp box 32. The bottom of the pulp suction mold 33 is driven by a supporting component to move upward or downward. Any of the hot press shaping zones 40 (either 40L or 40R) forms a working space 41. Inside the working space 41, a hot press upper mold 42 and a hot press lower mold 43 are provided. The hot press upper mold 42 is configured at an upper position inside the working space 41, and is hung on a rail, so that it can be pushed to move transversely. The mold surface of the hot press upper mold 42 faces downward. The hot press lower mold 43 is located below the hot press upper mold 42. The mold surface of the hot press lower mold 4 faces upward. The bottom of the hot press lower mold 43 is pushed by a power cylinder to move upward or downward.

The mold surface of the pulp suction mold 33 will be configured with multiple identical models, so that the multiple models will suck pulp all at once to accelerate the production One single model 33A on the mold surface of the pulp suction mold 33 is shown in FIG. 6. It is configured in the shape of a pulp molded cup lid. The mold surface of the pulp suction mold 33 has a plurality of models 33A arranged in an array. When the pulp suction mold 33 starts pulp suction, the top surface of each model 33A will suck a pulp layer 5A (see FIG. 6). Due to the high humidity at this time, the pulp layer 5A is obviously thick.

After completion of pulp suction, the pulp suction mold 33 will suck the whole pulp layer 5A and move upward to leave the pulp box 32. During the process, the sucking device (not shown in the figure) connected to the pulp suction mold 33 is started for suction, so that the pulp layer 5A is gradually dehydrated. Meanwhile, the hot press upper mold 42 is pushed to move toward the middle position and stops at the position above the pulp suction mold 33. Then, the pulp suction mold 33 moves upward to clamp with the hot press upper mold 42 to squeeze the pulp layer 5A. The mold surface of the hot press upper mold 42 will be configured with a plurality of identical models 42A that match the models 33A on the pulp suction mold 33 in both quantity and shape, to receive the clamping and squeezing by each model 33A. Each model 42A on the mold surface of the hot press upper mold 42 is as shown in FIG. 7. The shape of the model 42A is largely the same as the model 33A on the pulp suction mold 33, but there is a special position not matching the model 33A. This special structure refers to the ring-shaped groove 42B configured on the external edge on the side of the model 42A. Therefore, when the pulp suction mold 33 moves upward to clamp with the hot press upper mold 42 to squeeze the pulp layer 5A, as shown in FIG. 8, the pulp layer 5A is squeezed to become thinner. Meanwhile, some of the pulp enters the groove 42B and is kept there. Thus, on the pulp layer 5A, an integral internal snap ring 5a is produced. During the process of squeezing, the pulp layer 5A (including the internal snap ring 5a) will be dramatically dehydrated (comparing to the time when it just leaves the pulp box 32). Therefore, it becomes more solid and is shaped into a primary blank 5B (including the internal snap ring Sa).

When the squeezing working is completed, the sucking device connected to the pulp suction mold 33 is converted to a blowing device, so as to separate the mold from the primary blank 5B (including the internal snap ring 5a). Then, the mold moves downward to conduct pulp suction, which belongs to the next cycle. Meanwhile, the sucking device (not shown in the figure) connected to the hot press upper mold 42 is started to suck the primary blank 5B (including the internal snap ring 5a). As shown in FIG. 9, the hot press upper mold 42 sucks the primary blank 5B (including the internal snap ring 5a) and moves toward the original side to reset.

Then, the hot press lower mold 43 moves upward to clamp with the hot press upper mold 42 to conduct hot pressing and shaping for the primary blank 5B (including the internal snap ring 5a). The mold surface of the hot press lower mold 43 is configured with a plurality of identical models 43A that match the models 42A on the hot press upper mold 42 in both quantity and shape, so as to clamp with each model 42A for hot pressing. One model 43A on the hot press lower mold 43 is as shown in FIG. 10. The shape of the model 43A is largely the same as the model 42A on the hot press upper mold 42, but there is no structure that corresponds to the groove 42B.

When the hot press lower mold 43 moves upward to clamp with the hot press upper mold 42 to conduct hot pressing and shaping for the primary blank 5B (including the internal snap ring Sa), as shown in FIG. 11, under the heat and pressure, the primary blank 5B (including the internal snap ring 5a) will become thinner. Meanwhile, the internal snap ring 5a is heated and pressed so that it is firmly connected with the main body of the primary blank 5B (actually it is integrally formed). After completion of the hot pressing, the original primary blank 5B (including the internal snap ring 5a) is dried and shaped into a pulp molded cup lid 5C (including the internal snap ring 5a).

After the operation of hot pressing and formation, the hot press upper mold 42 is shifted from the sucking mode to the blowing mode, so as to be separated from the pulp molded cup lid 5C (including the internal snap ring 5a). Meanwhile, as shown in FIG. 12, the sucking device (not shown in the figure) connected on the hot press lower mold 43 is started to suck the pulp molded cup lid 5C (including the internal snap ring 5a), and the hot press lower mold 43 moves downward to reset, waiting for the material acquiring device (not shown in the figure) to remove and collect the pulp molded cup lid 5C (including the internal snap ring Sa).

The pulp molded cup lids 5C (including the internal snap rings 5a) completed after hot pressing and shaping are actually distributed in an array corresponding to the plurality of models 43A on the hot press lower mold 43. Therefore, when the material acquiring device removes the pulp molded cup lid 5C (including the internal snap ring 5a) from the hot press lower mold 43, a cutting operation is required, so as to separate the plurality of pulp molded cup lids 5C (including the internal snap rings 5a) connected to each other. As shown in FIG. 13, when a pulp molded cup lid 5C (including the internal snap ring 5a) is used to cover the lip of a corresponding cup body 2, the internal snap ring 5a can perfectly catch the convex edge 21 of the cup body 2, so that, after the coverage, it is hard to open the pulp molded cup lid 5C, preventing the liquid (especially hot liquid) inside the cup body 2 from spilling out.

Based on the above descriptions of the various structures, the formation and manufacturing of the pulp molded cup lid 5C (including the internal snap ring 5a) include the following steps:

- 1. The pulp suction mold 33 sucks pulp from inside the pulp box 32, so that the top surface of each model 33A is attached with a pulp layer 5A.
- 2. The hot press upper mold 42 moves toward the middle position, meanwhile the pulp suction mold 33 sucks the whole pulp layer 5A and moves up to clamp and squeeze with the hot press upper mold 42, so that an integral internal snap ring 5a is produced on the pulp layer 5A. Meanwhile, the pulp layer 5A (including the internal snap ring Sa) is squeezed and dehydrated to become more solid and is shaped into a primary blank 5B (including the internal snap ring 5a).
- 3. The pulp suction mold 33 is separated from the primary blank 5B (including the internal snap ring Sa) and moves downward to reset. Meanwhile, the hot press upper mold 42 sucks the primary blank 5B (including the internal snap ring Sa) and moves to the side to reset.
- 4. The hot press lower mold 43 moves up to clamp with the hot press upper mold 42, the primary blank 5B (including the internal snap ring 5a) undergoes hot pressing and shaping, so that the primary blank 5B (including the internal snap ring 5a) is dried and shaped into a pulp molded cup lid 5C (including the internal snap ring 5a).

From the above structures and manufacturing process, the formation of the internal snap ring Sa can be easily understood. When the pulp suction mold 33 sucks the pulp layer 5A and moves up to clamp with the hot press upper mold 42, because the pulp layer 5A is squeezed and partly goes into the groove 42B configured on the external edge on the side of the hot press upper mold 42, the internal snap ring 5a can be formed. Meanwhile, during the process when the pulp layer 5A is squeezed and shaped into the primary blank 5B, the internal snap ring 5a is also squeezed along with the pulp layer 5A and is dehydrated to become more solid, making the internal snap ring 5a an integral part of the primary blank 5B. Finally, after the primary blank 5B (including the internal snap ring 5a) undergoes hot pressing and shaping to become a pulp molded cup lid 5C, the pulp molded cup lid 5C will have the part of the internal snap ring 5a. Therefore, the internal snap ring 5a is already produced when the pulp suction mold 33 clamps with the hot press upper mold 42.

Based on the above descriptions, during the manufacturing process of the pulp molded cup lid, the pulp suction mold sucks the pulp layer and sends it to the hot press upper mold for clamping and squeezing so as to shape the pulp layer into a primary blank, meanwhile producing the part of internal snap ring on the primary blank. After hot pressing and shaping, the finished product of the pulp molded cup lid already has an internal snap ring. Therefore, comparing to the prior-art patents, the present invention neither requires a second operation (processing), nor a mold for the second operation (processing), and can save manufacturing cost and time.

Forming Structure for Internal Snap Ring of Pulp Molded Cup Lid

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