JPS63122530A - Forming device for paper vessel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for forming paper containers by drawing.

BACKGROUND ART Containers made of paper have come into widespread use in recent years because paper is light, has excellent heat insulation properties, and is easy to burn and dispose of.

On the other hand, paper does not have a lot of strength and properties, so when forming a container, ruled lines, that is, fold lines, are coined on the blank, and when forming the pattern, wrinkles are created along these lines. Generally, it is formed into a container shape.

Conventionally, in order to generate wrinkles with uniform size and spacing, the peripheral edge of the blank was held with elastic force of a predetermined strength and drawn. If this holding elastic force is too strong, the blank will break during pattern forming. On the other hand, if this elastic force is too weak, large wrinkles will occur locally, causing problems such as poor appearance. .

The appropriate range of this elastic force is relatively delicate, and its intensity is difficult to determine. First, if the elastic force required to generate wrinkles with uniform size and spacing is small, the elastic force is weaker than the frictional force when the support member moves up and down (this is likely to occur due to the position of the support member being unable to return to
This creates problems that make continuous production difficult. Furthermore, when this elastic force is generated using a normal metal spring, there are problems such as difficulty in maintaining this appropriate range over a long period of time.

Means for Solving the Problems According to the present invention, the above-mentioned problems are solved as follows: In a paper container forming apparatus for forming a paper container by drawing a blank, which is equipped with a punch and a die, the blank is ff! at the position where wrinkles are formed in the blank between the supporting members supporting the periphery. Gap C
(-1) and in the part of the blank where wrinkles are formed!
The ratio C/t0 of IJ and t0 (mm) is 3.58
> C/t0 > 1.59 by providing a paper container forming apparatus.

In this specification, the term "paper container" refers to not only a container formed from a single piece of paper such as paperboard or coated paper, but also a paper composite containing paper coated or impregnated with attenuated fat or wax, resin, etc. It also includes containers formed from materials, or laminates with plastics, metals, etc., including at least one layer of paper.

In addition, the thickness of paper specified in this specification is JIS 8
118-1976r Paper and Paperboard Thickness and Density Test Methods.

EMBODIMENT OF THE INVENTION A paper container forming apparatus according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

(Forming device of first embodiment) Forming device r! of FIG. 1! 110 includes a punch 14 fixed to an upper holder 12, a blank holder 16 fitted to the punch 14, and a die 18 fixed to a lower holder (not shown), and is shown in FIG. A circular tray 20 made of paper is formed as shown in FIG.

The upper holder 12 and the punch 14 fixed thereto by bolts 22 are provided with an air hole 24 for exhaust, thereby venting air during pattern forming.

The blank holder 16 is fitted into the punch 14 and includes, for example, three guide pins 2 fixed to the upper holder 12.
6 (only one is shown), it is supported so that it can move vertically but cannot rotate. Furthermore, the blank holder 16 is forced downward by the coil spring 28, and its downward movement is restricted by the shoulder 30 of the punch 14.

The die 18 is fixed to a lower holder (not shown), and is provided with an air hole 32 like the punch 14.

A recess 3G having a shape that matches the circular blank 34 is formed in the blank holder 16. According to the present invention, the depth of this r5 portion 36, that is, the gap C between the die 18 and the blank holder 16, is determined by the thickness of the paper 1. is selected to a predetermined value.

That is, the ratio C/t0 of the gap C (era) between the die 18 and the blank holder 16 to the paper thickness t, (ms) is set so that 3.58>C/t0>1.59. has been selected.

As detailed below (if this ratio C/t0 becomes 3.58 or more, large wrinkles will occur locally and the wrinkle size will increase).
The edges become uneven and the appearance deteriorates.

On the other hand, if this ratio C/t0 is less than 1.59, the blank will break during formation, making it impossible to properly form a container.

This forming device t10 operates as follows.

First, a circular blank 3 with radial ruled lines stamped on its periphery.
4 is placed in a predetermined position on the die 18.

Next, when a press fiIll (not shown) is operated to bring the upper holder 12 and lower holder (not shown) close to each other, the convex portion on the periphery of the blank holder 16 comes into contact with the die 18. Furthermore, when these are brought close to each other, the blank holder 16 resists the elastic force of the coil spring 28 and approaches the upper holder 12, and the bunch 14 moves closer to the blank 3.
4, the punch 14 and die 18 form the blank 34 into a container shape.

At this time, since the length of the peripheral edge of the blank 34 is reduced and stitched, wrinkles are generated along the ruled lines.

Gap C between die 18 and blank holder 16 and paper E
l Insert. If the ratio C/lO is selected within the above-described range, wrinkles as shown in FIGS. 3a to 3c will occur, for example, at the periphery of the blank 34 during the forming process. Then, a paper container having wrinkles of uniform size can be formed.

If the ratio C/lO between the gap C between the die 18 and the blank holder 16 and the thickness to of the paper is larger than the above range, wrinkles as shown in FIG. 4 will occur during formation, resulting in As a result, large wrinkles will be generated, making it impossible to form a good-looking paper container.

On the other hand, the dark rrRl between the die 18 and the blank holder 16
If the ratio C/L6 between liljC and the paper thickness to is smaller than the above range, the deformation resistance (shrinkage 7 run deformation resistance force) when the periphery of the blank 34 wrinkles increases, and the periphery of the blank 34 is narrowed. The resistance force (forming force) increases and the blank 34 breaks near the punch radius portion 166 during formation, making it impossible to form it properly.

(Square Tray) A square tray 38 as shown in FIG. 5 can be formed using an apparatus similar to the forming apparatus 10 shown in FIG. 1.

The 7-run shape of the rectangular tray 38 consists of a right side u40 and a corner portion 42. In the right side portion 40, only bending deformation is performed without shrinkage and 7-run deformation, and the corner portion 40 is simply bent.
2, a contraction 7-Runno deformation is performed.

The deformation at this corner portion 42 is substantially the same as the deformation at the periphery of the circular tray. Therefore, the gap C (
am) and the paper thickness to(-1) C/L. is selected so that 3.58>C/t0>1.59.

In the right side 11s40, no shrinkage deformation occurs as described above. Therefore, the gap c(e+a) between the die 18 and the blank holder 16 and the paper thickness t in this part
. (am) ratio C/t0 is C/Lo>1. o.

It is only necessary to select it so that it becomes .

In this case, if the ratio C/t0 at the right side portion 40 is selected to be a value larger than 1°59, the ratio C at the corner portion 42
/t0 and the ratio C/l at the right side portion 40.

It is also possible to make them the same. FIG. 6 shows a blank holder 44 that may form part of such a device. In this blank holder 44, the depth of the mouth portion 46 is uniform, so that the ratio C/t0 at the corner 11s42 and the ratio C/t0 at the proximal portion 40 are the same.

On the other hand, if a sufficient number of wrinkles are not generated in the corner portion 42, the right side portion 40 may be wrinkled and one or two wrinkles may be generated. In order to suppress wrinkles in the immediate area 40, the ratio C/l between the dark gap C(-1) between the die 18 and the blank holder 16 in this area and the lγ length t, (+am) of the paper. is selected so that 1.59>C/t0>1.00, more preferably 1.40>C/t0>1.00. rtS7 shows a blank holder 48 which may form part of such a device. In this blank holder 48, a corner portion 42
The depth of the recess at the side portion 40 is deep, and the depth of the recess at the right side portion 40 is shallow.

(Second aspect of forming apparatus!> The forming apparatus ra110 shown in FIG. 8 has an upper holder 1
A punch 114 installed in the lower holder 12, a folding ring 115 fitted to the punch 114, and a lower holder 1
58 and a blank holder 116 fitted to the die 118, forming a circular tray with 7-run folds.

The punch 114 is attached to the upper holder 112 in the vertical direction by, for example, three coil springs 150 and three coil springs 152 (only one of which is shown) arranged at equal angular intervals. It is set up so that it can be moved. punch 11
4 is provided with an air hole 124 for exhaust.

The folding ring 115 is fitted into the punch 114, and is fixed to the upper holder 112, e.g., three stripper poles 154 (only one shown) arranged at equal angular intervals, and the upper holder For example, three coil springs 156 (only one shown) are arranged between 112 and folding ring 115.
It is installed so that it can move up and down within a limited range.

The die 118 is attached to the lower holder 15 by the port 157.
8, and like the punch 114, the F hole 13
2.

The blank holder 116 is fitted into the die 118,
Similarly, it is forced upwardly by the fill spring 162, and its upward movement is restricted by the ζ guide bolt 160.

A recess 136 having a shape that matches the circular blank 134 is formed in the blank holder 116 . This four part 1
The depth of 36, ie the interleaving gap C between the folding ring 115 and the blank holder 116, is selected according to the invention to a predetermined value for the paper thickness to.

That is, the ratio C/t0 between the gap C (am) between the folding ring 115 and the blank holder 116 and the paper thickness t, ) (am) is 3.58>C/L. >1.59.

The forming device 110 operates as follows.

First, a substantially circular blank 134 with radial ruled lines stamped on its periphery is placed in the recess 136 of the blank holder 116.Next, a press mechanism (not shown) is operated,
When the upper holder 112 and the lower holder 158 are brought close to each other, a convex portion on the peripheral edge of the blank holder 116 comes into contact with the folding ring 115.

Further, when these are brought close to each other, the coil spring 162 for the blank holder 116 arranged below becomes the coil spring 1 for the folding ring 115 arranged above.
56, the folded ring 115 resists the elastic force of the coil spring 156 and approaches the upper holder 112. Then, punch 114 is blank 1
341: In contact, the punch 114 and die 118 form the blank 134 into a container shape. At this time, since the length of the peripheral edge of the blank 34 is reduced and stitched, wrinkles are generated along the ruled lines.

The upper holder 112 and the lower holder 158 are brought closer together, and the punch 114 is inserted into the die 1 through the blank 134.
18, i.e. punch 114, blank 13
The prayer return ring 115 contacts the upper holder 112 at a position where there is substantially no space between the opening of the holder 4 and the die 118.

Furthermore, when the upper holder 112 and the lower holder 158 are brought close to each other, the folding ring 115 is in contact with the upper holder 112 and does not move upward, so the folding ring 115 causes the blank holder 116 to resist the coil spring 162. and move it downward, then punch 11.
4 is in contact with the die 118 via the blank 134, so it is moved upward against the coil spring 150. This forms a fold in the outermost portion of the blank 134.

Also in this forming device 110, the folding ring 115
Since the ratio C/t0 between FIXC and the paper thickness to between the blank holder 116 and the blank holder 116 is selected within the above range, for example, the blank 13
Wrinkles of uniform size will occur around the periphery of 4.

In addition, in the above-mentioned aspect, a support member that supports the peripheral edge of the blank during drawing forming, for example, the folding ring 1
A recess is provided in the blank holder 116, which is one of the blank holder 15 and the blank holder 116, and a gap C is formed between them. The four parts may be provided on both sides, and the gap may also be formed by a spacer separate from these members.

Examples In Examples 1.2 and 3, JIS P8118
- each material thickness measured using a method based on 1976
to"0.251mw5to=0.314-1,t,=
In Example 4, resin-coated paper with a material thickness of t0 = 0.378 mm measured in the same manner was used.

Width x length x corner radius of curvature = 116
A blank was produced by cutting into a rectangular shape measuring 178 mm x 178 mm x 34 mm, and radially stamping a ruled line (fold line) with a depth of about 0.1 mm on a part of the corner.

Moisture content M (%) of these blanks (M=L/5x
ioo, where S is the weight of the blank (g) and L is the weight loss (g) when the blank is dried at 100±3°C for 2 hours)
was 5-6%.

Using these blanks, make a mold as shown in Figure 11 with a rectangular opening of width x length x radius of corner curvature = 84 soso x 145 + 5m x 16- and depth 15mm, and create a gap C (m■). Tray-shaped containers were formed by varying the ratio C/t0 between the sample and the thickness t (am) of the material.

It was evaluated whether the size of the wrinkles generated along the ruled line of a part of the corner of the tray-shaped container was uniform and whether the tray-shaped container could be formed. The results are shown in Table 1.

In Table 1, wrinkles that occur along ruled lines are considered to be good (marked with ○) if they are uniform in size or wrinkles that are approximately the same size, and those in which wrinkles occur along the ruled lines are considered good (marked with ○), and wrinkles that occur along the ruled lines are considered good (marked with ○), and wrinkles that occur along the ruled lines are considered good (marked with ○). Items with uneven wrinkles and poor appearance are considered defective (
× mark).

Regarding whether or not the formation was possible, those that broke at the corner corner of the tray-like container 166 (Fig. 5) were marked as unacceptable (x mark), and those that could be formed without breaking were marked as good (○ mark). .

As shown in Table 1, the interval C (ms) and the material thickness t
If the ratio C/t0 to o (-ring) is C/t0≦1.59, it cannot be formed (x mark), and if C/t0≧3.58, large wrinkles will occur locally and the size will increase. The appearance is poor due to irregular wrinkles (x mark), and 3.58>C/t0>
Good results were obtained in the range of 1.59.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a forming apparatus according to a preferred embodiment of the invention. FIG. 2 is a perspective view of a circular tray formed by the forming apparatus shown in FIG. 1. FIGS. 3(a) to 3(c) are cross-sectional views of examples of well-formed wrinkles. Pt54 diagram is a cross-sectional view of an example of wrinkles in bad form. ms diagram is a perspective view of a square tray formed by a forming apparatus similar to the forming apparatus shown in FIG. 1. 6 is a perspective view of an example of a blank holder that can be used in the forming apparatus for forming the rectangular tray shown in FIG. 5. FIG. FIG. 7 is a perspective view of another example of the blank holder similar to FIG. 6. FIG. 8 is a cross-sectional view of a forming apparatus according to another preferred embodiment of the invention. 10.110...Forming device 12.112...Upper holder 14.114...Punch 16.116...Blank holder 18.118 ・φ φ die 20 ・Circular tray 34.134... Blank 36.136...Concavity 38...Square tray

Claims (1)

[Claims] 1. In a paper container forming apparatus for forming a paper container by drawing a blank, which is equipped with a punch and a die, the blank is placed between support members that support the periphery of the blank during drawing. Gap C (m
m) and the thickness t of the blank at the part where the wrinkles are formed
The ratio C/t_0 to _0 (mm) is 3.58>C/t_
A paper container forming apparatus characterized in that 0>1.59. 2. The paper container forming apparatus according to claim 1, wherein the supporting member is constituted by a die and a blank holder. 3. The paper container forming apparatus according to claim 1, wherein the support member is constituted by a folding ring and a blank holder. 4. Claim 1, wherein a recess is formed in one of the support members, thereby forming the gap C.
The paper container forming apparatus according to any one of Items 1 to 3. 5. Claim 1, wherein a recess is formed on both sides of the support member, thereby forming the gap C.
The paper container forming apparatus according to any one of Items 1 to 3. 6. The paper container forming apparatus according to any one of claims 1 to 3, wherein a spacer is arranged between the supporting members, thereby forming the gap C.