JP3396947B2 - Method for producing deformed seamless cans - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a relatively elongated seamless can used for carbonated drink cans, beer cans, coffee drink cans, fruit drink cans and the like.

[0002]

2. Description of the Related Art Conventional seamless cans such as squeezed and ironed cans (so-called DI cans) and squeezed and re-squeezed cans used in carbonated beverage cans, coffee beverage cans, etc. It was cylindrical throughout. Therefore, there were the following problems. When empty cans are conveyed on the conveyor with no gaps and in close contact with each other while being shaken at high speed in the can making process, filling process, etc., the bottom corner of the adjacent empty can hits the body part and the body part has a defect such as a dent. Is likely to occur. When used for so-called negative pressure canned products (canned products whose internal pressure is lower than atmospheric pressure) filled with coffee drinks, fruit drinks, etc., the body is likely to be dented. When several stages are stacked on a refrigerating shelf such as a supermarket without any gap, the one placed near the center requires a relatively long time for cooling because the circulation of cold air is poor. If you drop this type of canned food on a slope, you will end up rolling straight, and it will be extremely difficult to chase after it, and sometimes it will be lost.

[0003]

DISCLOSURE OF THE INVENTION The present invention is intended for use in negative pressure canning, because it is unlikely to cause a defect such as a dent in the body when conveyed while being in close contact with a conveyor in an empty can state and shaking at high speed. Even when used, the body is difficult to dent, and even when several cans are stacked in a refrigerating shelf without gaps, the cans placed near the center cool relatively quickly, and when the cans are dropped on a slope, etc. But
An object of the present invention is to provide a method for manufacturing a deformed seamless can that is relatively easy to pick up.

[0004]

According to the method for producing a modified seamless can of claim 1 of the present application, the seamless can body 11 is made into a diameter reducing die 2.
Placed on the hole 22 of No. 1, inside the seamless can body 11,
The diameter of the upper end portion 33a is such that it can be loosely inserted into the open end portion 12b of the seamless can body 11, the diameter of the body main portion 33b is set smaller than the inner diameter of the working surface 22b of the diameter reducing die 21, and the supporting tool By inserting and lowering the punch 32 suspended to form a gap 26 with respect to 30, the main body portion 12c of the seamless can body 11 is moved to the working surface 2 of the diameter reducing die 21.
The step of pressing the main body portion 33b of the punch 32 by 2b to reduce the diameter is performed at least once to form the reduced lower cylindrical portion having the reduced diameter portion and the step, and the diameter is reduced. And a tapered portion 52 having an inverted truncated cone shape in the lower cylindrical portion.
By inserting and lowering the rigid punch 52 having b, the reduced diameter portion is expanded by the taper portion 52b of the rigid punch 52 to shape the lower cylindrical portion into an inverted truncated cone shape.

According to the method for manufacturing a modified seamless can of claim 2, the seamless can body 11 is placed on the hole portion 22 of the diameter reducing die 21, and the diameter of the upper end portion 33a is within the seamless can body 11. The size of the body portion 33b is set so that it can be loosely inserted into the open end 12b of the seamless can body 11, and the diameter of the body main portion 33b is set smaller than the inner diameter of the working surface 22b of the diameter-reducing die 21. Insert the punch 32 that has been formed and suspended.
By lowering, the body main portion 12c of the seamless can 11 is pressed against the body main portion 33b of the punch 32 by the working surface 22b of the diameter reducing die 21 to reduce the diameter at least once. To form a diameter-reduced lower cylindrical portion having a diameter-reduced portion and a step. Inside the diameter-reduced lower cylindrical portion, a rigid body portion 78 having an upper portion and a lower inverted truncated cone shape having lower elasticity are hollow elastic bodies. By inserting and lowering the punch 76 including the portion 79, the reduced diameter portion is spread by the elastic portion 79, and the lower cylindrical portion is formed into an inverted truncated cone shape. In the modified seamless can manufacturing method of claim 3, in the case of the preceding paragraph, an air blow-in introduction hole is provided in a punch that forms the lower cylindrical portion into an inverted truncated cone shape, and the punch is blown while blowing pressurized air. It is characterized in that the punch is pulled out from the base can by raising it, and the lower cylindrical portion is formed into an inverted truncated cone shape. The method for manufacturing a modified seamless can according to claim 4, wherein in the case of the preceding paragraph, an outer surface of the cylindrical body of the seamless can body, which has the shape of an inverted truncated cone, is externally printed in a pre-distorted shape, and then the inverted cone is formed. It is characterized in that it is formed in a trapezoidal shape.

[0006]

In the deformed seamless can produced by the production method of the present invention, the upper part of the body is a cylindrical part, and the lower part is
It has an inverted truncated cone shape, that is, a downward tapered shape.
Therefore, in the can making process and the filling process, even when the empty cans are conveyed on the conveyor with the upper part in close contact with each other while shaking at high speed, there is a considerable gap between the adjacent bottoms of the empty cans. Therefore, it is unlikely that the bottom corner of the adjacent can hits the body to cause a defect such as a dent in the body. When used for negative pressure canning, an inward force due to atmospheric pressure acts on the body. However, since the cross-section in the height direction of the body portion has a shape close to an arch, due to the so-called arch effect, when the thickness and hardness are equal to other conditions, the body portion is less likely to be dented and deformed than when the body portion is cylindrical. Even if the upper part is stacked in several rows on a refrigerating shelf such as a supermarket without any gap, there is a considerable gap in the lower part of the adjacent cans, so the cans placed near the center also pass through the gap. Since it is exposed to cold air sufficiently, it is cooled for a relatively short time. Even if the canned food is dropped on a slope or the like, it rolls toward the lower part of the inverted truncated cone shape and easily hits an obstacle at the roadside or the like to stop, so it is relatively easy to chase and pick up.

In the method for producing a modified seamless can according to the present invention, first, a cylindrical body of a seamless can is first formed from a bottom side to a hole having a predetermined depth in a hole portion of a diameter reducing die which is smaller than an outer diameter of the body. The indenting step is performed at least once to form a reduced diameter lower cylindrical portion. Forming the lower cylindrical part without wrinkles in steps by appropriately setting the number of steps at this time according to the thickness and hardness of the body of the seamless can or the type of tool. You can Next, the diameter-reduced lower cylindrical portion is formed into an inverted truncated cone shape, but in this case, since there is no compression processing, wrinkles hardly occur. In addition, the lower cylinder part has increased the meat pressure than before the diameter reduction, and it seems that it is due to the Bausinger effect,
Since it is softer than before the diameter reduction (for example, the Vickers hardness Hv is reduced from 230 to 217), cracking is unlikely to occur when forming into an inverted truncated cone shape. When the lower part of the seamless can body is directly compression-processed by a die or the like to form an inverted truncated cone shape without going through the step of forming the diameter-reduced lower cylindrical part, remarkable vertical wrinkles are likely to occur. . Also, when a seamless can body with a total height equal to the diameter of the lower cylindrical portion is expanded by a rigid punch or elastic internal pressure to form a deformed seamless can with a large upper diameter, the body of the seamless can body is Since the portion is stretched in the height direction and the extension rate in the circumferential direction is small, the body portion is easily broken.

Further, in the method for manufacturing a deformed seamless can according to the present invention, the rigid punch is pushed into the seamless can body having the reduced diameter lower cylindrical portion, and the reduced diameter lower cylindrical portion is expanded. Therefore, as described above, wrinkles are less likely to occur when forming the lower cylindrical portion. Moreover, since a rigid punch is used, the life of the punch is long. Further, in the method for manufacturing a modified seamless can according to the present invention, an elastic pressure or a fluid pressure is applied to the lower cylindrical portion in a state where the reduced lower cylindrical portion is inserted into a die having an inverted truncated cone-shaped cavity. Since the lower cylindrical portion is expanded, as described above, wrinkles are less likely to occur when the lower cylindrical portion is formed. Further, elastic pressure or fluid pressure is applied to the lower cylindrical portion by, for example, a punch made of elastic rubber to expand the lower cylindrical portion into an inverted truncated cone shape, so that the inner organic coating is less likely to be damaged by friction. Furthermore, in the method for producing a modified seamless can according to the present invention, since the outer surface of the cylindrical body of the seamless can is previously printed, it is possible to produce a modified seamless can having a satisfactory printing surface. it can. Since the print screen is formed in the shape of a circular truncated cone to the shape of an inverted truncated cone, it tends to extend in the height direction and contract in the circumferential direction. Therefore, a desired print screen can be obtained after deformation by performing so-called distortion printing, in which characters, images, barcodes, and the like are printed in advance in an appropriately distorted form only in the portion having the inverted truncated cone shape. It is very difficult to simultaneously and satisfactorily print the outer surface of the upper cylindrical portion and the lower portion of the inverted truncated cone shape simultaneously in the deformed seamless can.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A modified seamless can 1 according to an embodiment of the present invention shown in FIG. 1 has an inverted frustoconical shape in which an outer diameter of an upper portion 2a made of a cylindrical portion and an upper end portion 2b1 is equal to the outer diameter of the upper portion 2a. That is, the outer diameter is gradually reduced toward the bottom 5 with a relatively gentle gradient, and the lower end 2b2 is a body 2 having a short cylindrical lower part 2b, and the smooth neck-in part 3 is connected to the upper end of the upper part 2a. , A flange portion 4 and a bottom portion 5. The upper end 2b1 of the lower portion 2b is at a position approximately half the height of the can 1, in the case of FIG. 1, slightly higher than half. Although not shown, the neck-in part 3 may be a multi-stage neck-in part. The upper end 2b1 may be located at an appropriate position depending on the use of the can or the like, but when rolling on a gently sloping surface such as a slope, the inverted frustoconical lower part 2b comes into contact with the ground and rolls. Further, it is preferable that the height is about 1/2 or more from the bottom with respect to the total height of the can 1. On the other hand, the height of the cylindrical upper portion 2a is about ⅓ or more of the total height of the can 1 so that adjacent cans can be stably aligned when packing the cans of this kind side by side. It is preferable. From these points, the upper end 2b1 is about 1 from the bottom with respect to the total height of the can 1.
It is preferably / 2 to 2/3. The bottom portion 5 is provided with a chime portion 5a, a ground contact portion 5b composed of a curved portion, an inner wall portion 5c rising slightly inward from the ground contact portion 5b, and a dome-shaped central panel portion 5d, and is excellent in buckling resistance. There is.

The outer diameter of the lower end 2b2 of the lower portion 2b is such that the cans produced from the modified seamless can 1 can be stacked on top of each other, that is, the contents 7
After filling the can, the can lid 6 is double-wound, and the neck of the can (the double-wound portion is not shown) can be placed on the double-wound portion of the can. It is desirable that the inner diameter is approximately equal to the inner diameter of the neck portion 3a of the in portion 3. The intersecting portion 8 between the lower end 2b2 and the chime portion 5a slightly protrudes, as will be described later, when the lower portion 2b is formed, and may not be protruded depending on the condition for forming the lower portion 2b. it can.

Next, an embodiment of a method of manufacturing the modified seamless can 1 will be described. 2 to 8 show a step of forming a reduced diameter cylindrical portion below the body portion 12 of the seamless can body 11. In FIG. 2, reference numeral 11 denotes a seamless can body formed from a circular blank (not shown) by drawing-ironing, drawing-thinning redrawing, drawing-thinning redrawing-ironing, and the like. The seamless can body 11 has a bottom portion 15 including a chime portion 15a curved inward, a ground portion 15b, and a dome-shaped central panel 15c. The chime portion 15 a is connected to the body portion 12 via the curvature portion 13. Deformed seamless can 1 of body 12
The thickness of the opening end portion 12b including the neck-in portion 3 and the flange portion 4 of the
It is slightly larger than the thickness of c. In the body 12,
The outer surface is previously printed by a conventional method.

As a material for the blank, various surface-treated steel plates and light metal plates such as aluminum thin plates are used.
As the surface-treated steel sheet, cold rolling, or subsequent annealing, secondary cold rolling, one or more surface treatments such as tin plating, nickel plating, zinc plating, aluminum plating and electrolytic chromic acid treatment are performed. There are things like Among them, tin-plated steel sheet having a plating amount of 0.5 to 11.2 g / m ² , or 10 to 200 mg / m
An electrolytic chromic acid-treated steel plate (tin-free steel) having a ^second metal chromium layer and a chromium oxide layer of 1 to 50 mg / m ² (metal chromium conversion) thereon is preferably used.
The latter is excellent in work adhesion and corrosion resistance to the organic coating, and is therefore preferably used as an organic coating-coated blank in the case of thin-walled redraw forming. As a light metal plate,
A so-called pure aluminum plate or an aluminum alloy plate is used. Among them, Mn 0.1 to 1.5% by weight, Mg 0.
12-5% by weight, Zn 0.01-0.4% by weight, Cu
0.15-0.45% by weight, Si 0.6% by weight or less, F
An aluminum alloy having a composition of 0.7% by weight or less and the balance of Al is preferably used because it has excellent corrosion resistance and workability.

The thickness of the blank varies depending on the kind of metal, the use of the deformed seamless can, the size, the shape, etc., but is generally 0.1 to 0.5 mm, and the thickness of the surface-treated steel sheet is 0.1 to 0. 3 mm, 0.15 to 0.
4 mm is preferably used. The strength of the blank varies depending on the type of metal plate, thickness, use of deformed seamless can, size, shape, processing method of the seamless can body 11, etc., but in the case of the surface-treated steel plate, it is 33 to 80 kgf / m.
m ² and a light metal plate having a tensile strength of 23 to 42 kgf / mm ² is preferably used. When the seamless can body 11 is formed by drawing-ironing (so-called DI molding), the thickness (metal portion) of the body 12 is 0.06 to 0.
It is preferably 2 mm. JP-A 1-255822
In the case where the seamless can body 11 is formed by using thinning and redrawing molding as disclosed in Japanese Patent Laid-Open Publication No.
The thickness of 2 is 60 to 90% of the thickness of the blank.

It is preferable that both surfaces of the seamless can body 11 have an organic film coated at the time of blanking or after the seamless can body 11 is formed. This is because in addition to improving the storage performance as a can, when forming the deformed seamless can 1, the frictional resistance between the tool and the seamless can body 11 is reduced to facilitate molding. Examples of the organic coating film coated at the time of blanking include a coating film made of a thermosetting resin or a thermoplastic resin, or a thermoplastic resin film. The thickness of the coating film (in the dry state) is 2 to 20 from the viewpoint of corrosion resistance and workability.
It is preferably μm. In the case of a thermoplastic resin film, it is usually covered by thermal bonding. From the viewpoint of processing adhesion and corrosion resistance, a polyester film having a thickness of 10 to 30 μm formed by unstretching or biaxial stretching is preferably used from the viewpoint of processing adhesion and corrosion resistance. Seamless can 11
When the organic film is to be coated after the above condition, a method generally used for DI cans, that is, spray coating, roller coating, or the like is adopted.

The die device 20 includes a diameter-reducing die 21 having a hole portion 22 and a knockout plate 25. The diameter reducing die 21 is fixed to the die plate 23 by a support 24. The knockout plate 25 is a shaft 25a that is inserted through the through hole 23a of the die plate 23.
Via a drive device (not shown) such as an air cylinder.

The inner peripheral surface of the hole 22 has a shape corresponding to the body lower end 12a and the curved portion 13 near the curved portion 13 of the seamless can body 11, that is, the body lower end 12a and the curved portion 1.
Seat part 2 that can seat 3 almost exactly
2a, a working surface 22b that is connected to the lower end of the seat portion 22a and hangs downward, and a flank 22c that extends obliquely downward and outward. The inner diameter of the action surface 22b is set to be equal to the outer diameter of the lower portion of the body portion 12 to be reduced in diameter (see the reduced diameter portion 40a in FIG. 6).

In FIG. 3, the punching device 28 for reducing the diameter is
A punch support 30 attached to the punch plate 29, a bolt 31 and a punch 3 screwed to the punch support 30.
Equipped with 2. The punch plate 29 can be reciprocated (moved up and down in the case of a figure) with a predetermined stroke length by a drive mechanism (not shown: crank mechanism, for example). The punch support tool 30 includes a main portion 30a and a main portion 30.
It has a short cylindrical lower projection 30c connected to a via a step portion 30b extending in the radial direction. The diameter of the lower projection 30c is the relatively thick open end 12b of the seamless can body 11.
It has a size that can be loosely inserted into. The side surface 30c1 of the lower protrusion and the step portion 30b intersect at a right angle to the cross section. The punch 32 has an upper hole portion 3 through which the bolt 31 is inserted.
2a, a lower hole portion 32b that is connected to the upper hole portion 32a via a step portion 32b1 is provided, and as shown in the figure, the step portion 32b1 is engaged with the upper surface 31a1 of the bolt head 31a, and the punch 32 is It is suspended at a distance from the support tool 30, that is, a gap 26 is formed.

The diameter of the upper end portion 33a of the body portion 33 of the punch 32 is set so that it can be loosely inserted into the open end portion 12b of the seamless can body 11. The diameter of the trunk main portion 33b below the upper end 33a is equal to that of the working surface 22 of the diameter reducing die 21.
It is set to be smaller than the inner diameter of b by 2x (1.1 to 1.5) xt (t is the thickness of the main body portion 12c of the seamless can body 11). The bottom portion 34 of the punch 32 has a curved portion 34a connected to the lower end of the body main portion 33b, a step portion 34b extending radially inward from the end of the curved portion 34a, an annular projection 34c connected to the inner end of the step portion 34b, and The inner peripheral surface, which is located inside the annular protrusion 34c and communicates with the lower hole portion 32b, is provided with a concave portion 34d having a short cylindrical shape. Punch 32 seamless can body 1
1, the bottom curved portion 34a and the bottom surface of the annular projection 34c contact the inner surface near the upper end of the chime portion 15a of the seamless can 11 and the inner surface of the ground portion 15b, respectively, as shown in FIG. And the height h1 of the gap 26 is
Body end face 12d of seamless can 11 and step 30 of support
The size of each part is determined so that it is larger than the height h2 between the inner ends 30b1 of b. The punch support 30 and the punch 32 are formed with an air blow-out guide hole 35 that is connectable via a gap 26 and is connected to a pressurized air source (not shown).

The above die device 20 and punch device 28
Thus, the seamless can body 40 having one step (hereinafter referred to as a one-step seamless can body: see FIG. 6) is formed as follows. As shown in FIG. 2, a seamless can body 11
Is placed on the sheet portion 22a of the hole 22 of the diameter reducing die 21. At this point, the punch 32 of the punch device 28 is located right above the seamless can body 11 at a height at which the distance from the body end face 12d is at least about twice the can height. In this state, the punch plate 29 descends, and as shown in FIG.
The annular projection 34c of the punch is the grounding portion 1 of the seamless can body 11.
It contacts the inner surface of 5b. When the descent is further continued, as shown in FIG. 4, the body end face 12d of the seamless can body contacts the inner end 30b1 of the step portion of the punch support, and the body part 12c of the seamless can body 11 becomes , Decreasing diameter die 21
Is pressed against the main body portion 33b of the punch by the working surface 22b of the punch to reduce the diameter, and the reduced diameter portion 40a and the reduced diameter die 21
A step 40b having a shape corresponding to the seat portion 22a is formed. When the height of the reduced diameter portion 40a becomes almost half of the total height of the seamless can body 11, the punch plate 29 reaches the bottom dead center and thereafter rises, and the punch 32 moves to the reduced diameter portion 40a.
And the single-step seamless can body 40 having the step 40b formed thereon (FIG. 5). Immediately, the knockout plate 25 rises and pushes up the one-step seamless can body 40 above the diameter reducing die 21 (FIG. 6).

FIGS. 7 and 8 show the main part of the process of forming the two-step seamless can body 41 from the one-step seamless can body 40. The main difference between the tool used and the case where the one-step seamless can body 40 is formed is that the lower projection 37a1 (corresponding to 30c in FIG. 3) of the punch support 37a of the punch device 37 is formed by molding. In this case, the body end face 40d of the one-step seamless can 40 is so long that it does not come into contact with the step 37c (FIG. 8), and the radius of curvature of the bottom curvature portion 37a2 of the lower protrusion 37a1 is equal to that of the inner surface of the step 40b. That, punch 37b
The diameter of the body portion of the two is substantially equal to the inner diameter of the reduced diameter portion 41a of the two-step seamless can body 41 to be formed over the entire height, and a plurality of small spring constants are provided between the lower protrusion 37a and the punch 37b. The coil springs 39 are provided at equal intervals, and the inner diameter of the working surface 38a of the die 38 is equal to the outer diameter of the reduced diameter portion 41a of the two-step seamless can body 41. The diameter of the lower projection 37a1 is set to such a size that it can be loosely inserted into the upper portion 40c of the one-step seamless can body 40. The plurality of coil springs 39 are for correctly positioning the punch 37b during molding, and do not function as a pressing cushion.

The two-step seamless can body 41 is formed as follows. As shown in FIG. 7, one-step seamless can body 4
0 is seated on the seat portion 38a of the die 38 (the cross-sectional shape is substantially the same as the seat portion 22a of FIG. 3, but the inner diameter is different), and then the punch 37b and the lower projection 37a1 are respectively attached to the seamless can body 40. The reduced diameter portion 40a and the upper portion 40c are inserted. When the punch device 37 is immediately lowered, since the coil spring 39 is weak, the punch 37b remains in the position shown in FIG. 7 and only the lower projection 37a1 is lowered so that the bottom curvature portion 37a2 contacts the step 40b.

When the punch device 37 is further lowered, the step portion 40b is pressed by the bottom curvature portion 37a2, while the reduced diameter portion 40a is pressed against the side wall of the punch 37b by the working surface 38a of the die 38 and contracted. The diameter is reduced to form the reduced diameter portion 41a. The lowering of the punch device 37 is stopped just before the bottom curvature portion 37a2 contacts the upper corner 38a1 of the seat portion 38 via the step 40b (FIG. 8).
At this point, the second step 41b is formed and the two-step seamless can body 41 is formed. The subsequent operation is the same as in the case of forming the one-step seamless can body 40. Then, the two-step seamless can body 41 is replaced with the step 42 by using the same device except that the inner diameter of the working surface and the diameter of the punch are smaller.
Formed into a 3-step seamless can body 42 (FIG. 9) having b1, 42b2 and 42b3. The reason why there are three steps in the above method is that the upper surface of the step during molding is free, and therefore wrinkles are likely to occur in the step when the radial width of each step is increased. Therefore, a blank can 1'described later (see FIG. 13)
When the difference in diameter between the upper part 1'a and the lower part 1'b of the lower part is relatively small, or the body part of the seamless can body 11 is relatively thick,
The number of steps may be one or two when wrinkles are unlikely to occur in the case of being soft. If necessary, four or more steps may be formed. Further, where two or more steps are formed, the steps may be smoothly connected to each other in a tapered shape so that the steps are not formed.

9 to 13 show a three-step seamless can body 42.
3A to 3D are drawings for explaining a process of forming a plain can 1 ′ of the modified seamless can 1. Bed 50 (Fig. 9)
The short cylindrical portion 5 having a shape corresponding to the vicinity of the bottom portion 45 including the lower end portion 42a1 of the reduced diameter portion 42a of the seamless can body 42.
A concave portion 51 having a peripheral surface composed of a curved portion 51b which is slightly convex toward the inner side is formed which is connected to 1a and the short cylindrical portion 51a via a sharp corner 51c. The inner diameter of the short cylindrical portion 51a is set so that the lower end portion 42a1 of the reduced diameter portion can be loosely inserted, that is, there is a slight gap between the short cylindrical portion 51a and the lower end portion 42a1. Figure 1
As shown in FIG. 0, a rigid punch 52 fixed to a punch plate 53 (for example, tool steel, cemented carbide, ceramics or the like tool) that can be moved up and down at a predetermined timing and stroke length by a drive mechanism (not shown). The outer peripheral surface (of the material) has a shape substantially corresponding to the inner surface of the body portion 2 of the deformed seamless can 1 to be formed. That is, the punch 52 has a cylindrical cylindrical portion 52a having a diameter substantially equal to the inner diameter of the open end 42c of the three-step seamless can body 42.
The taper portion 52b has a shape of an inverted truncated cone that gradually becomes thinner toward the bottom portion 52c. The diameter of the lower end 52b1 of the taper portion 52b is 3 steps and the reduced diameter portion 42 of the seamless can body 42.
equal to the inner diameter of a. The bottom 52c of the punch 52 is formed with a short cylindrical recess 52c1 communicating with an air blowing guide hole 54 connected to a pressurized air source (not shown). This is to accommodate the central panel 45b at the end of molding (FIG. 12).

The modified seamless can 1 is formed as follows using the bed 50 and punch 52 described above. The three-step seamless can body 42 is inserted and placed in the recess 51 of the bed (FIG. 9), and the rigid plate punch 52 together with the punch plate 53.
Is lowered and pushed into the seamless can 42. Punch 52
The lower end 52b1 of the tapered portion 52b of the
After contacting the reduced diameter portion 42a of FIG. 10 (FIG. 10), the reduced diameter portion 42a is expanded from above by the taper portion 52b as the punch descends, and the steps 42b3, 42b2 and 42b1 disappear sequentially (FIG. 11). Then, as shown in FIG. 12, when the bottom surface 52c2 of the punch reaches almost the same level as the upper surface 50a of the bed 50, the punch 52 reaches the bottom dead center and the upper portion 1'a is cylindrical and the lower portion 1'a is cylindrical. A base can 1'of a modified seamless can 1 having a shape of an inverted truncated cone 1'b is formed.
Lower end 1'b1 of the lower part of the bare can 1 '(deformed seamless can 1
(See FIGS. 1 and 13) slightly protrudes because there is a slight gap between the short cylindrical portion 51a and the lower end portion 42a1 (FIG. 9). This is because 1'b1 is slightly expanded.

Next, the pressurized air 5 is supplied from the air blowing introduction hole 54.
Punch 5 while raising 5 while blowing 5.
2 is pulled out from the can 1 '(FIG. 13). After that, can 1 '
Is taken out of the bed 50 and the open end 1'of a relatively thick wall
The modified seamless can 1 having the neck-in portion 3 and the flange portion 4 is manufactured by subjecting a1 to the neck-in processing and the flange processing by a conventional method. The diameter of the grounding portion 5b of the modified seamless can 1 is the same as the diameter of the grounding portion 15b of the seamless can body 11.

A seamless can body 56 with one step (hereinafter referred to as a seamless can body 56 with one step) whose outer diameter of the reduced diameter portion from the seamless can body 11 is equal to that of the seamless can 42 with three steps.
(See FIG. 18) is shown in FIGS. 14 to 18 in which the steps are formed without wrinkles. Figure 14
The punch device 60 used in this case is shown. The punch device 60 includes a punch 62 fixed to a punch plate 61, a wrinkle retainer 63, and a wrinkle retainer plate 64. The wrinkle retainer 63 is inserted through the through hole 64a of the wrinkle retainer plate 64 and is normally suspended as shown by a plurality of bolts 65 screwed to the flange portion 63a. Flange portion 63a and wrinkle holding plate 6
Coil springs 66 for cushioning are provided between 4 to surround the bolts 65. Between the punch 62 and the wrinkle retainer 63, a gap portion 67 having a slight gap width that does not interfere with each other is provided. The diameter of the wrinkle retainer 63 is set to a size such that it can be loosely inserted into the open end 12b of the seamless can body 11. The bottom portion 68 of the punch 62 has a curved portion 68 connected to the lower end of the side wall portion 62a.
a, a stepped portion 68b extending inward in the radial direction from the end of the curved portion 68a, an annular protrusion 68c connected to the inner end of the stepped portion 68b, and an inner peripheral surface located inside the annular protrusion 68c has a concave portion 68d having a short cylindrical shape. I have it.

As shown in FIG. 15, the punch device 60 is provided.
Below the, compared to the die assembly 20 shown in FIG.
The inner diameter of the working surface 44b is equal to the outer diameter of the reduced diameter portion 56a of the one-step seamless can body 56, and accordingly the radial width of the seat portion 44a is provided with a diameter reduction die 43 larger than that of the seat portion 22a. A die device 46, which is similar except for the above, is provided. The lower end surface 63b of the wrinkle retainer 63 has a shape corresponding to the sheet portion 44a of the diameter reducing die 43.
The inner diameter of the inner peripheral surface 63c of the wrinkle retainer 63 is equal to the diameter reduction die 43.
Is substantially equal to the inner diameter of the working surface 44b. The diameter of the punch 62 is set to be smaller than the inner diameter of the working surface 44b of the diameter reduction die 43 by 2x (1.1 to 1.5) xt (t is the thickness of the main body portion 12c of the seamless can body 11). Has been. As shown in FIG. 16, when the punch 62 is pushed into the seamless can body 11, the bottom surface of the bottom annular protrusion 68c is
The size and shape of the punch 62 are determined so as to contact the inner surface of the grounding portion 15b of the seamless can body 11. The punch 62 is formed with an air blowing guide hole 69 that is connected to a pressurized air source (not shown) and reaches the recess 68d.

The die device 46 and punch device 60 described above
Thus, the one-step seamless can body 56 is formed as follows. In the same manner as in the case of forming the one-step seamless can body 40, the seamless can body 11 is attached to the hole 4 of the diameter reducing die 43.
4 is placed on the seat portion 44a (this state is not shown). At this point, the punch 62 and the wrinkle retainer 63 of the punch device 60 are located right above the seamless can body 11 at a height such that the distance from the body end face is at least about twice the can height. In this state, as shown in FIG. 15, the wrinkle retainer plate 64 descends, and at the same time, the wrinkle retainer 63 descends so that the lower end surface 63b thereof is elastically pressed by the pressing spring 66 to bend the curved portion 13 of the seamless can body 11. Also, the upper half of the chime portion 15a is pressed.

The punch plate 61 immediately descends, and the annular projection 68c of the punch comes into contact with the inner surface of the grounding portion 15b of the seamless can body 11 as shown in FIG.
The main body portion 12c of No. 1 is squeezed by the working surface 44b of the diameter-reducing die 43 under pressure by the wrinkle retainer 63 to reduce the diameter, and corresponds to the diameter-reduced portion 56a and the sheet portion 44a of the diameter-reduction die 43. A one-step seamless can body 56 having a step 56b shaped like this is formed. The punch plate 61 reaches the bottom dead center when the height of the reduced-diameter portion 56a becomes almost half of the total height of the seamless can body 11, and thereafter, the pressurized air 70 is blown from the air blowing guide hole 69. While rising, the punch 62 is 1
The stepless seamless can body 56 is pulled out, and then the wrinkle retainer 63 and the wrinkle retainer plate 64 are lifted out of the one step seamless canister 56 (FIG. 17). Immediately, the knockout plate 59 rises, and the one-step seamless can body 56
Is pushed up from the diameter reducing die 43 (FIG. 18).

19 to 25 show an embodiment in which a base can 1'of a modified seamless can 1 is formed from a seamless can body with steps using an elastic punch. In FIG. 19, the die device 7
1 includes a die 73 fixed to the bed 72, a recess 75 of the bed 72, and a knockout plate 74 that can move up and down in the cavity 73a of the die 73. The peripheral surface 73a1 of the cavity 73 is a blank can 1'to be formed.
It has a truncated cone shape corresponding to the lower part 1′b (see FIG. 13) of the inverted truncated cone shape. The inner peripheral surface of the concave portion 75 has a short cylindrical surface portion 75a having an inner diameter equal to the outer diameter of the lower end portion 42a1 of the reduced diameter portion 42a of the three-step seamless can body 42, and the chime portion 42.
It comprises a curved portion 75b having a shape corresponding to the upper portion of a2 and a short cylindrical surface portion 75c hanging from the lower end of the curved portion 75b. The knockout plate 74 is formed with an annular cutout portion having an L-shaped cross section, which is composed of a horizontal portion 74a and a hanging portion 74b along the upper surface rim. The knockout plate 74 is always in contact with the bottom surface 75d of the recess 75,
With the chime portion 42a2 at the bottom of the seamless can body 42 seated on the bed 72, the horizontal portion 74a has the seamless can body 4
2 grounding portions (corresponding to 5b of the modified seamless can 1),
The hanging portion 74 is dimensioned so as to contact the inner wall portion (corresponding to 5c of the deformed seamless can 1).

As shown in FIG. 20, the punch plate 77 is used.
The punch 76 fixed to the main part is mainly composed of a rigid portion 78 (made of, for example, tool steel or the like) in the upper portion, and a hollow elastic portion 79 (made of, for example, elastic rubber or elastic plastic) in the lower portion. The outer diameter of the rigid body portion 78 is set to be substantially equal to the inner diameter of the open end portion 1′a1 (FIG. 13) of the base can 1 ′. The outer surface of the elastic portion 79 has a cylindrical portion 79a at the top,
Inverted frustoconical portion 79b whose lower portion extends slightly inward and downward
It has become. The hollow portion 81 has the enlarged diameter portion 80a at the lower end.
And a central shaft 80 screwed to the rigid body portion 78 through
The elastic portion 79 is fixed to the rigid body portion 78. Central axis 80
Further, the rigid body portion 78 is formed with an air blowing guide hole 82 communicating with a pressurized air source (not shown). Expanded part 8
A concave portion 80a1 is formed on the lower surface of 0a. The height from the bottom surface of the central shaft 80 to the upper surface of the elastic portion 79 is set to be slightly higher than the height of the lower portion 1′b of the bare can to be formed.

Using the die device 71 and the punch 76 described above, the base can 1'is formed from the three-step seamless can body 42 as follows. After inserting and placing the three-step seamless can body 42 in the cavity 73a of the die and the recess 75 of the bed 72 (FIG. 19), as shown in FIGS. 21, 22 and 23, the punch plate 77 is lowered. , Punch 7
6 is pushed into a three-step seamless can body 42 (not shown, a one-step seamless can body 56 may be used). Deformation of the seamless can 42 hardly occurs until the lower end of the elastic portion 79 contacts the upper step 42b1 (FIG. 21), but when the punch 76 further descends, the upper step 42b1 and the intermediate step 42
b2 and the lower step 42b3 are pressed against the cavity peripheral surface 73a1 of the die 73 by the elastic portion 79 to disappear (FIG. 22), and the reduced diameter portion 42a is sequentially arranged from the upper side on the peripheral surface 73a.
The lower part 1'of the shape of an inverted circular truncated cone is pressed against 1 and expands.
A bare can 1 ′ having b is formed (FIG. 23). At this time, the central panel (corresponding to 5d of the deformed seamless can 1) enters the recess 80a1. Immediately after the pressurized air 83 is blown out from the air blow-out guide hole 82, the punch 76 is raised to be pulled out from the raw can 1 '(FIG. 24). Next, the knockout plate 74 is raised to push out the can 1'from the die 73 (FIG. 25).

The modified seamless can according to claim 1 can take various forms other than the embodiment shown in FIG. For example, as shown in FIG. 26, a modified seamless can 1 for negative pressure canning in which the central panel 105d of the bottom 105 is flat.
May be 05. In this case, accurate internal pressure (negative pressure) measurement is easy by vibrating the panel unit 105d with a percussion instrument (not shown). The deformed seamless can 101 is a seamless can body 1 similar to the seamless can body 11 except that the bottom central panel 111d is flat.
11 (FIG. 27) is manufactured in the same manner as the modified seamless can 1. Also, as shown in FIG. 28, a modified seamless can 201 similar to the modified seamless can 101 except that the lower portion 202b of the body is slightly recessed inward.
May be The modified seamless can 201 is particularly suitable for use in negative pressure canned products having an internal pressure lower than atmospheric pressure, such as coffee drink cans. The deformed seamless can 201 includes a cavity peripheral surface (73) of a die (73) used when forming a blank can.
a1: See FIG. 19) except that the shape corresponding to the lower portion 202b is formed, and the modified seamless can 101 is manufactured in the same manner.

Further, as shown in FIG. 29, the bottom annular protrusion 301b has a chime portion (5a), which is a simple curved portion, and the body 301a and the central panel 301c directly connect the annular protrusion 301b. It may be a modified seamless can 301 of a type that is connected via. The deformed seamless can 301 is similar to the seamless can 11 except that the deformed seamless can 311 has an annular projection 311a made of a curved portion having a relatively large radius of curvature, as shown in FIG. It is manufactured by a method similar to. Further, the neck-in part may be a single-step or multi-step neck-in part. Also, there is no neck-in part, and the upper part 2a
The flange portion may be directly formed on the upper end of the. Although not shown in the drawings, after forming a blank can by the above method from a seamless can body having a flat bottom, an annular protrusion and a central panel may be formed on the bottom. In the state of FIG. 19, the fluid pressure (liquid pressure or gas pressure) to the extent that the bottom central panel (5d) does not buckle inside the three-step seamless can body 42.
In addition, the reduced diameter portion 42a and the steps 42b1, 42b2,
42b3 may be expanded to form a can 1 '(Fig. 24). Similarly, fluid pressure may be applied to the one-step seamless can body 56 to form the canister 1 ′.

[0035]

EFFECTS OF THE INVENTION The deformed seamless can produced by the production method of the present invention is less likely to cause a defect such as a dent in the body when it is conveyed in an empty can state while being in close contact with the conveyor and shaking at high speed. Even when it is used for negative pressure canning, the body is not likely to be dented, and even when it is stacked on a refrigerating shelf etc. without gaps, the cans placed near the center cool relatively quickly and Even when dropped on a slope or the like, it is relatively easy to pick up. Furthermore, in the case of the modified seamless can manufactured by the manufacturing method of the present invention, the upper part has a nominal can diameter of about # 211 (diameter about 66.2 mm) and the inner capacity is about 350 ml. Since it is easy to grasp the lower portion by hand, there is an advantage that it is easy to drink the content beverage or the like directly from the opening of the can lid.

Further, the method for producing a deformed seamless can of the present invention has an effect that a deformed seamless can having an inverted frustoconical shape at the lower part of the body can be produced without generating wrinkles or cracks, and the life of the punch is increased. It has the advantage of being long. Furthermore, the manufacturing method of the modified seamless can of the present invention,
It also has an advantage that the inner organic coating is less likely to be damaged and a deformed seamless can having a satisfactory outer printed surface can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a modified seamless can according to a first embodiment of the present invention.

FIG. 2 is a view showing an example of forming a three-step seamless can body having a reduced lower cylindrical portion for manufacturing the modified seamless can of FIG. 1, in which a cylindrical seamless can body is die-cast. It is a longitudinal cross-sectional view showing a state of being placed on.

3 is a longitudinal sectional view showing a state in which a punch is inserted in the seamless can body of FIG.

FIG. 4 is a view of the seamless can body of FIG. 3 having a lower cylindrical portion 1
It is a longitudinal cross-sectional view showing a state immediately after the stepless seamless can body is formed.

5 is a vertical cross-sectional view showing a state in which a punch is pulled out from the seamless can body of FIG.

FIG. 6 is a vertical cross-sectional view showing a state where the seamless can body of FIG. 5 is pushed up.

7 is a vertical cross-sectional view showing a state in which a one-step seamless can body is placed on a die and a punch is inserted to form a two-step seamless can body from the one-step seamless can body of FIG. is there.

8 is a vertical cross-sectional view showing a state immediately after a two-step seamless can body is formed from the one-step seamless can body of FIG.

9 is a view showing a first embodiment for forming a plain can of the modified seamless can of FIG. 1 from a three-step seamless can body, in which the three-step seamless can body is placed on a bed. It is a longitudinal cross-sectional view showing a state.

FIG. 10 is a vertical cross-sectional view showing a state immediately before the lower portion of the seamless can body of FIG. 9 is opened by a punch.

11 is a vertical cross-sectional view showing a state in which the seamless can body of FIG. 9 is being expanded by a punch.

FIG. 12 is a vertical cross-sectional view showing a state immediately after the unsealing of the seamless can body of FIG. 9 is finished and a blank can is formed.

FIG. 13 is a vertical cross-sectional view showing a state immediately after the punch is pulled out from the raw can of FIG.

14 is used in an example of forming a one-step seamless can body having a lower cylindrical portion reduced in diameter to the same diameter as the three-step seamless can body of FIG. 9 to manufacture the modified seamless can of FIG. It is a longitudinal cross-sectional view of the punch device.

15 is a vertical cross-sectional view showing a state in which the wrinkle retainer of the punch device shown in FIG. 14 is inserted into a seamless can body mounted on a die.

FIG. 16 is a diagram showing a case where a punch is pushed into the seamless can body shown in FIG.
It is a longitudinal cross-sectional view showing the state immediately after the one-step seamless can body is formed.

FIG. 17 is a vertical cross-sectional view showing a state where the punch device is extracted from the one-step seamless can body of FIG. 16.

FIG. 18 is a vertical cross-sectional view showing a state where the one-step seamless can body of FIG. 16 is pushed up onto the die.

FIG. 19 is a view showing a second embodiment for forming a plain can of the modified seamless can of FIG. 1 from a three-step seamless can body, in which the three-step seamless can body is placed on a die. It is a longitudinal cross-sectional view showing a state.

20 is a vertical cross-sectional view of a punch for forming a blank can of the modified seamless can of FIG. 1 in cooperation with the die of FIG.

21 is a vertical cross-sectional view showing an initial state in which a punch is inserted into the three-step seamless can body of FIG.

22 is a vertical sectional view showing a state where a punch is pushed into the three-step seamless can body of FIG.

23 is a longitudinal sectional view showing a state immediately after the base can of the modified seamless can of FIG. 1 is formed from the three-step seamless can body of FIG.

FIG. 24 is a vertical cross-sectional view showing a state where a punch is extracted from the bare can of FIG.

FIG. 25 is a vertical cross-sectional view showing a state where the blank can of FIG. 24 is pushed up from a die.

FIG. 26 is a vertical cross-sectional view of a modified seamless can according to the second embodiment of the present invention.

27 is a vertical cross-sectional view of a seamless can body used to form the modified seamless can of FIG.

FIG. 28 is a vertical sectional view of a modified seamless can according to a third embodiment of the present invention.

FIG. 29 is a vertical sectional view of a modified seamless can according to a fourth embodiment of the present invention.

30 is a longitudinal sectional view of a seamless can body used to form the modified seamless can of FIG. 29. FIG.

[Explanation of symbols]

1 deformation seamless can 2 torso 2a upper part 2b lower part 4 Flange part 11 Seamless can body 12 torso 15 bottom 21 diameter reduction die 22 holes 42 (3 steps) Seamless can body 42a Reduced diameter portion (reduced diameter lower cylindrical portion) 43 diameter reducing die 52 Rigid body punch 56 (1 step) Seamless can body 56a Reduced diameter portion (reduced diameter lower cylindrical portion) 73 die 73a cavity 101 Deformed Seamless Can 201 deformed seamless can 301 Deformed seamless can

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A 1-226550 (JP, A) JP-A 2-156243 (JP, A) JP-A 60-82228 (JP, A) JP-A 55- 54223 (JP, A) JP-A-61-56736 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B65D 1/16 B21D 41/02 B21D 41/04

Claims (4)

(57) [Claims] 1. A seamless can body 11 is provided with a hole 2 of a diameter reducing die 21.
2 and is placed in the seamless can body 11 and has an upper end 33
The diameter of a is such that it can be loosely inserted into the open end 12b of the seamless can body 11, the diameter of the body main portion 33b is set smaller than the inner diameter of the working surface 22b of the diameter reducing die 21, and Punch 32 suspended to form a gap 26
By inserting and lowering the main body 12c of the seamless can body 11 into a diameter-reducing die 21
The action surface 22b of the punch 32 presses the body 32b of the punch 32 to reduce the diameter to form a diameter-reduced lower cylindrical portion having a diameter-reduced portion and a step. By inserting and lowering the rigid punch 52 having an inverted truncated cone-shaped tapered portion 52b in the reduced diameter lower cylindrical portion, the reduced diameter portion is expanded by the tapered portion 52b of the rigid punch 52 to expand the lower cylindrical portion. A method for producing a deformed seamless can, which is characterized by forming into an inverted truncated cone shape. 2. A seamless can body 11 is provided with a hole 2 of a diameter reducing die 21.
2 and is placed in the seamless can body 11 and has an upper end 33
The diameter of a is such that it can be loosely inserted into the open end 12b of the seamless can body 11, the diameter of the body main portion 33b is set smaller than the inner diameter of the working surface 22b of the diameter reducing die 21, and Punch 32 suspended to form a gap 26
By inserting and lowering the main body 12c of the seamless can body 11 into a diameter-reducing die 21
The action surface 22b of the punch 32 presses the body 32b of the punch 32 to reduce the diameter to form a diameter-reduced lower cylindrical portion having a diameter-reduced portion and a step. Inside the reduced cylindrical portion, the upper portion is a cylindrical rigid body portion 78, and the lower portion is an inverted truncated cone-shaped hollow elastic portion 79.
A method of manufacturing a deformed seamless can, comprising inserting and lowering a punch 76 made of the material to spread the reduced diameter portion by an elastic portion 79 to form the lower cylindrical portion into an inverted truncated cone shape. 3. A punch for molding the lower cylindrical portion into an inverted truncated cone shape is provided with an air blow-in introduction hole, and the punch is lifted while ejecting pressurized air to extract the punch from the can. The method for producing a modified seamless can according to claim 1 or 2, wherein the portion is formed into an inverted truncated cone shape. 4. The inverse frustoconical shape is formed by printing the outer surface of the cylindrical body portion of the seamless can body, which has an inverted frustoconical shape, in a distorted shape in advance, and then printing the outer frustoconical shape. 3. The method for producing a modified seamless can according to any one of 3 above.