JP6873609B2 - Metal cans and their manufacturing methods - Google Patents

Description

The present invention relates to a can formed of a thin metal plate as a material, and more particularly to a metal can having a body formed into a special shape other than a simple cylindrical shape and a method for manufacturing the same.

Metal cans such as beverage cans are required not only to have airtightness and strength for holding and protecting the contents, but also to be easy to hold, openable, and have excellent designability to attract customers. Since the body of a metal can (hereinafter referred to as the can body) is most noticeable and it is usually handled by holding the can body, various metal cans with elaborate shapes of the can body have been proposed in the past. Has been done. For example, in Patent Document 1, a groove-shaped recess is formed in a substantially central portion in the height direction of the can body over the entire circumference, the diameter of the can body is 60 to 70 mm, and the can body is in the direction of the central axis. A metal can in which the length of the recessed portion is 20 to 80% of the height of the can body and the position of the deepest portion of the recessed portion is 10 to 40% lower than the upper end of the can body is described. The metal can described in Patent Document 1 is configured for the purpose of improving ease of holding and cooling efficiency by heat dissipation.

Further, in Patent Document 2, a substantially central portion in the height direction of the can body is constricted, and a plurality of reinforcing beads along the circumferential direction are formed in the constricted portion (constricted portion), and the constricted portion is formed. A can with a bead is described so that the height of the reinforcing bead gradually increases on the deepest side. The beaded can described in Patent Document 2 is configured for the purpose of equalizing the distribution of strength and suppressing the shortening of the height of the can as much as possible. Further, Patent Document 3 describes a metal container having a can body having a peculiar shape and being configured to improve buckling strength. This container forms a retracted portion that recedes inward from the outer surface of the body at two points facing each other in the diameter direction of the body, and a plurality of vertical beads (in the direction of the central axis of the body) inside the retracted portion. A bead along the line) is formed, and the portion of the outer surface of the body portion other than the retracting portion is configured as a cylindrical non-molded portion.

Further, Patent Document 4 and Patent Document 5 describe a method of forming a body portion having a special shape different from the cylindrical shape. In the method described in Patent Document 4, the body portion is drawn from the opening portion of the body portion toward the bottom portion, and then the portion extending from the position closer to the opening portion than the bottom portion to the opening portion is formed. The outer diameter is expanded, and the portion of the expanded portion on the opening side is drawn again to draw the portion closer to the bottom than the expanded portion. It is a method of forming a part. Further, in the method described in Patent Document 5, the peripheral wall portion forming the body portion is sandwiched between the outer tool and the inner tool to form a narrow and shallow annular concave groove, and further, the annular concave groove is formed. This is a method of forming a wide and deep bead by grooving the part with another outer tool and inner tool.

Japanese Patent No. 5290632 Jitsukosho 60-4904 Japanese Unexamined Patent Publication No. 2014-61919 Japanese Patent No. 4217992 Special Publication No. 62-1934

In the metal can described in Patent Document 1, since the substantially central portion of the can body is recessed, the finger holding the metal can does not slip easily in the vertical direction, and in this respect, the metal can can be easily held. .. However, since the dented portion is smooth in the circumferential direction, if the can body is wet due to dew condensation or the like, the finger holding the dented portion is slippery in the circumferential direction, and it is difficult to grasp (hold) at this point. ) There is a possibility that it will become a metal can. Further, since the recessed portion acts to increase the surface area of the can body, heat exchange between the contents and the outside is promoted, and the cooling efficiency becomes good when the contents are cooled. On the other hand, when the temperature of the contents is high, heat dissipation to the outside is promoted, so that the amount of heat transferred to the finger holding the dent is increased, and the person holding the metal can feels hot or metal. There is a possibility that it will often not be possible to hold a can.

Further, in the can described in Patent Document 2, since a so-called horizontal bead is formed at a portion confined over the entire circumference of the can body, the shape of the can body is special. However, the configuration described in Patent Document 2 has a structure similar to that in which a so-called bellows is provided in a part of the can body, so that the rigidity or strength of the can body in the central axis direction (vertical direction) is low. It ends up. Therefore, for example, there is a possibility that the can body may be deformed without being able to withstand the lifter pressure of the seamer to which the can lid is attached, and in order to prevent such deformation, there is a problem that the plate thickness of the can body must be increased. Occurs. Further, since the horizontal bead extends in the circumferential direction, even if the finger holding the can body is not slippery in the vertical direction, it is slippery in the circumferential direction, which makes the can difficult to hold. Furthermore, if a barcode is attached to the surface of the can body, each bar should be attached side by side in parallel with the axis direction (vertical direction) of the can body in order to minimize the change in distance from the leader. However, in the configuration described in Patent Document 2, if the bar code is hung on the horizontal bead, the bar code may not be read accurately.

Further, in the metal container described in Patent Document 3, since the retracting portion is formed in a part of the outer circumference of the can body (two places facing each other in the diameter direction), the metal container (or the can body) can be used depending on the viewing direction. The shape or appearance will be different. That is, the structure becomes directional. Therefore, the non-molded portion may be gripped with a finger to hold the metal container, and in that case, since the simple cylindrical portion is gripped, the finger is slippery and the container becomes difficult to hold. In addition, since the outer surface of the body has two types, a retracted portion with a vertical bead and a cylindrical non-molded portion, the recessed portion and the non-molded portion are used for printing such as product display and decoration. It becomes necessary to specify one of them, or the boundary between them, and therefore, when printing or processing the recessed part, the posture (orientation) of the metal container must be determined one by one, and manufacturing workability is such. Has a drawback.

On the other hand, in the method described in Patent Document 4, since drawing processing for reducing the outer diameter and diameter expansion processing for increasing the outer diameter are performed, the inner surface of the body portion is rubbed and the metal surface is partially exposed. There is a possibility that it will end up. Further, in the method described in Patent Document 5, two processes, a process of forming a narrow and shallow concave groove and a process of forming a wide and deep bead, are performed, so that man-hours are required. In addition, there are problems such as large size or complicated equipment.

The present invention has been made in the context of the above circumstances, and although it has a peculiar shape other than a simple cylindrical shape, it does not impair other functions such as ease of holding and manufacturing. And the purpose of the present invention is to provide a method for producing the same.

To achieve the above object, the present onset Ming, the metal can body portion is formed into a cylindrical shape by a metal thin plate, the upper end and the lower end portion of the body portion and the respective cylindrical upper cylindrical portion A plurality of vertical beads extending in the direction of the central axis of the body portion and swelling linearly are formed in the middle portion between the upper cylindrical portion and the lower cylindrical portion, which is regarded as a lower cylindrical portion, over the entire circumference. The intermediate portion is formed in an arc shape in which the ridgeline of the vertical bead is gradually curved inward in the radial direction of the body portion from the upper cylindrical portion and the lower cylindrical portion to a portion between these cylindrical portions. The most constricted part of the middle part is the minimum outer diameter part, and the vertical bead is the valley part between the ridges of the adjacent vertical beads. The bead height, which is the dimension from the valley portion to the ridge line, is the highest in the minimum outer diameter portion and gradually decreases in the upper cylindrical portion side and the lower cylindrical portion side. is there.

In the present invention, the height is 80 mm or more and 170 mm or less, the outer diameters of the upper cylindrical portion and the lower cylindrical portion are 50 mm or more and 70 mm or less, and the body portion of the constricted portion in the intermediate portion is used. The length in the central axis direction is 40 mm or more and 120 mm or less, and the outer diameter of the minimum outer diameter portion formed by the ridgeline of the vertical bead is 85% of the outer diameter of the upper cylindrical portion or the lower cylindrical portion. It may be more than and 95% or less.

Further, in the present invention, the thickness of the body portion is 0.1 mm or more and 0.25 mm or less, the bead height is the highest in the minimum outer diameter portion, and the upper cylindrical portion side and the lower portion. it becomes increasingly lower cylindrical portion, the lowest height at which the highest height becomes the gradually lower at 1.5mm or less Ru der least 0.3 mm.

Further, in the present invention, the pitch of the vertical beads may be 3.5 mm or more and 5.5 mm or less.

On the other hand, the method of the present invention is a method for producing a metal can gradually smaller constricted portion outer diameter to a cylindrical barrel made of a thin metal plate is made form the entire circumference, the rotation to the outer peripheral portion around A plurality of concave portions and convex portions extending in a direction parallel to the axis and retracting in a radial direction perpendicular to the rotation center axis so that the outer diameter gradually decreases in the middle portion in the rotation center axis direction. The core having the formed core is inserted into the body portion, and has a rib portion that bites into the concave portion and a concave groove portion that bites the convex portion, and the rib portion and the concave groove portion are formed with each other. While pressing the body portion by the core, the body is pressed against the outer mold protruding toward the core so as to have a shape corresponding to the receding of the concave portion and the convex portion in the radial direction. The portion is relatively moved and rotated along the outer mold together with the core, and the concave portion and the convex portion and the rib portion and the concave groove portion mesh with each other to cover the entire circumference of the body portion. over the longitudinal bead is formed extending in the center axis direction of the front kidou portion, and the engagement depth of the concave portion and the engagement depth and the ridge of the rib portion and the groove portion, the The vertical bead and the constricted portion whose height gradually changes by being deep at the concave portion and the portion of the convex portion that is most retracted in the radial direction and gradually becoming shallower as the distance from the portion is increased are simultaneously provided. It is a method characterized by molding.

In the method of the present invention, the number of the rib portion and the groove portion provided in the outer mold is greater than the number of the longitudinal bead is formed in the body portion, the front kidou portion inserting said core The moving distance along the outer mold may be longer than the length of the outer circumference of the body portion.

Further, in the method of the present invention, the number of the convex portions and the concave portions provided on the core is 60% or more and 70% or less of the number of the vertical beads formed on the body portion. The vertical bead can be formed by rotating the core more than one rotation.

According to the onset bright, and constricted portion between the upper and lower cylindrical portion of the body portion over the entire circumference, the longitudinal bead of the plurality of are formed on the constricted portion, the appearance is singular It has a shape and is excellent in design, or has an excellent function of attracting the attention or eyes of the purchaser. In particular, in the invention of claim 1, since the height of the vertical bead is high in the minimum outer diameter portion, the so-called surplus due to the narrowing of the outer diameter is sufficiently absorbed by the vertical bead, and the constricted shape and the vertical bead are formed. The shape of can be made into a smooth shape. Further, since the constriction and the vertical bead are formed over the entire circumference of the body portion, the so-called directionality of the body portion or the metal can as a whole does not occur. Therefore, there are no restrictions on the printing of the body and the display of the metal can, and it becomes easy to handle or handle the metal can or the product in which the metal can is filled with the contents at the time of manufacturing. Furthermore, since the body is constricted, the finger holding the body is prevented from slipping in the vertical direction, and the vertical bead is formed so that the finger holding the body is slipped in the circumferential direction. Since it is suppressed, it can be a metal can that is easy to hold by hand. The finger holding the torso comes into contact with the ridgeline of the vertical bead, and the contact area between the torso and the finger becomes smaller, so heat transfer from the finger to the torso is suppressed and the contents of the metal can are less likely to warm up. On the contrary, when the temperature of the metal can is high, the heat transfer to the finger is suppressed and the purchaser is less likely to feel hot. When printing the barcode bars side by side in the direction of the central axis of the can body, even if the barcode hangs on the vertical bead, one of the bars will not be buried between the vertical beads. It can be a metal can that does not interfere with reading. Furthermore, even if the body portion is constricted over the entire circumference, a vertical bead is formed in the entire confined portion, so that a decrease in buckling strength can be suppressed.

According to the onset bright, the minimum outer diameter of the portion that the constriction, since 95% or less of the original outer diameter of ie constricted portion of the upper cylindrical portion or the lower cylindrical portion, constricted body portion or specific shape Is surely or strongly recognized, and since it is 85% or more of the original outer diameter, it is possible to avoid or suppress that the visibility of the printed image applied to the body portion is impaired.

According to the onset bright, since the height of the bead was 0.3mm be lowest, clearly be a longitudinal bead visible, also the height of the bead was 1.5mm be highest Therefore, it becomes easy to process a vertical bead without breakage or cracking of the body portion, and a metal can with good manufacturability can be obtained.

According to the onset bright, since the pitch of the longitudinal beads were or more and less 5.5 mm 3.5 mm, with vertical beads is visually clear, since no such excessive coining during molding, cracks Ya Abnormalities such as breakage are less likely to occur.

According to the method of the present invention, since the vertical bead can be formed at the same time as the body is constricted, the number of steps for manufacturing the metal can can be reduced, and the coating film on the inner surface of the body is damaged. This can be prevented or suppressed. Further, since the meshing depth between the concave portion and the rib portion and the meshing depth between the convex portion and the concave groove portion at the portion to be constricted most are deepened, the so-called surplus meat accompanying the constriction is beaded. It can be absorbed and processed into a constricted shape and a bead shape with no disorder in shape.

According to the method of the present invention in particular, since the processing of the longitudinal bead to rotate the barrel 1 rotating or more, a vertical bead at the machining start portion to be processed twice, machining lack or processing of the portion Defects can be avoided or suppressed.

Then , according to the method of the present invention, since the core can be made smaller in diameter than the body portion, it is easy to put the core in and out of the body portion, and when the core is rotated by one or more rotations, the core has already been rotated. It is possible to stably process the vertical bead by reducing the difference in pitch between the formed vertical bead and the convex portion and the concave portion.

It is a front view which shows an example of the metal can which concerns on this invention. It is sectional drawing which follows the line II-II of FIG. It is sectional drawing which follows the line III-III of FIG. It is a chart which shows the result of having evaluated the constriction about Examples 1 to 3 and Comparative Examples 1 and 2 collectively. It is a figure for demonstrating the part where the height of a vertical bead is the smallest, (a) shows the end part of a vertical bead, and (b) is the arrow view along the line BB of (a). .. It is a chart which shows the result of having evaluated the finish of the vertical bead about Examples 4 to 6 and Comparative Examples 3 and 4. It is a chart which shows the result of having performed the constriction evaluation about Examples 7 to 9 and Comparative Examples 5 and 6. It is a chart which shows the result of the sensory test of the heat and the ease of holding a metal can and a normal can according to the Example of this invention in the hand. It is a figure which shows an example of the change of the shape when the method in the Example of this invention is carried out. It is a schematic diagram for demonstrating the process of processing a vertical bead and a constriction part by a core and an outer die. It is a figure which shows typically the state which the peripheral wall part of a rough-printed material is sandwiched between a core and an outer mold. It is a front view which shows an example of a core. It is a side view which shows an example of an outer mold. It is explanatory drawing which shows the state which the print rough shape material is formed by the outer mold. It is a partial cross-sectional view which shows the meshing state of the concave part and the convex part in the core in the upper end side or the lower end side in a constriction part, and the rib part and the concave groove part in an outer mold. It is a partial cross-sectional view which shows the meshing state of the concave part and the convex part in the core in the minimum outer diameter part in a constriction part, and the rib part and the concave groove part in an outer mold.

The metal can 1 according to the present invention is a container whose body is formed of a thin metal plate at least, and typical examples are a metal two-piece can, a metal three-piece can, and a metal reseal can. Therefore, the material is steel, aluminum, aluminum alloy, or the like. FIG. 1 is a two-piece can for beverages, which is an embodiment of the present invention, and is a DI can (a can formed by drawing and ironing) in which a body 2 and a bottom 3 are integrally formed. In the case of a two-piece can, the bottom portion 3 is subjected to a doming process that is convex inward, and in the case of a three-piece can, it is formed by a flat bottom lid.

A flange portion 4 for attaching a can lid (not shown) is formed at the upper end portion of the body portion 2. The lower portion following the flange portion 4 is a neck-in portion 5 that has been neck-in processed so that the outer diameter gradually decreases toward the flange portion 4. A lower portion following the neck-in portion 5 and a portion above the bottom portion 3 are formed in a cylindrical shape, and these portions form an upper cylindrical portion 6 and a lower cylindrical portion 7. The upper cylindrical portion 6 and the lower cylindrical portion 7 may have the same outer diameter or may have different outer diameters.

The portion between the upper cylindrical portion 6 and the lower cylindrical portion 7 is a constricted portion 8 having an outer diameter smaller than those of the cylindrical portions 6 and 7. The constricted portion 8 is a portion formed over the entire circumference of the body portion 2 and whose outer diameter gradually decreases toward the intermediate portion in the direction along the central axis of the constricted portion 8. A plurality of vertical beads 9 are formed in the constricted portion 8 along the direction of the central axis (or the bus line of the body portion 2). The vertical bead 9 is a portion linearly raised on the outer surface side of the constricted portion 8, and the ridge line 9a forms a straight line in the direction of the central axis of the body portion 2 and the body portion 2 in the radial direction of the body portion 2. It has an arc shape that is smoothly convex toward the inside (smoothly recessed inward from the outer surface of the body portion 2).

The ridges 9a form the outer diameter of the constricted portion 8, and the ridges 9a of the vertical beads 9 farthest in the diameter direction of the body 2 face each other at intervals (when the number of vertical beads 9 is an odd number) or on the diameter. The distance between the ridge lines 9a (when the number of vertical beads 9 is an even number) is the outer diameter of the constricted portion 8. As shown in FIGS. 2 and 3, the outer diameter of the constricted portion 8 is the smallest in the middle portion in the central axis direction of the constricted portion 8. The position of the minimum outer diameter portion 8a is a position slightly lower than the central portion in the central axis direction of the constricted portion 8, and a position slightly lower than the central portion in the central axis direction of the body portion 2. It has become. The reason why the minimum outer diameter portion 8a is set to be slightly lower than the central portion in the central axis direction is to make the shape similar to a beverage container such as a cup.

The dimension from the valleys 9b on both sides sandwiched by the ridge line 9a to the ridge line 9a is the height Hb of the vertical bead 9, and the height Hb of the vertical bead 9 is the above-mentioned upper cylindrical portion as shown in FIGS. 2 and 3. It gradually changes so as to be the lowest on the 6 and the lower cylindrical portion 7 side and the highest on the minimum outer diameter portion 8a. The cross-sectional shapes of the ridge line 9a and the valley portion 9b are rounded as shown in FIGS. 2 and 3.

In the metal can 1 according to the embodiment of the present invention, the plate thickness of the body portion 2 is 0.1 mm or more and 0.25 mm or less, and the outer diameter of the body portion 2 (outside the above-mentioned upper cylindrical portion 6 and lower cylindrical portion 7). A metal can having a diameter) of 50 mm or more and 70 mm or less. The height H is 80 mm or more and 170 mm or less. The height H of the metal can 1 is the height from the bottom 3 to the flange 4 in the case of the two-piece can shown in FIG. 1 or the three-piece can (not shown), and in the case of the reseal can, the mouth from which the male screw is formed from the bottom. The height to the lower end of the neck. Further, the length (length in the vertical direction) L of the constricted portion 8 is 40 mm or more and 120 mm or less. This is determined based on the design of the metal can 1. Since the constricted portion 8 is a portion deformed by a process of reducing the outer diameter of the body portion 2, its length L is the length of the portion where such deformation occurs in the direction of the central axis of the body portion 2. May be. Therefore, even if the constricted portion 8 is not actively processed, the length of the portion having a trace of deformation (for example, the deformed portion that occurs as so-called sagging) occurs at the upper end portion and the lower end portion of the constricted portion 8 due to the processing of the constricted portion 8. It may be the end of L.

<About the minimum outer diameter of the constricted part>
The outer diameter Dmin of the minimum outer diameter portion 8a of the constricted portion 8 is smaller than the original outer diameter before the constriction processing, that is, the outer diameter D0 of the upper cylindrical portion 6 and the lower cylindrical portion 7, and the ratio of the diameters (diameter ratio) is It is 85% or more and 95% or less. This is based on the results of the experiments below. A can diameter of 66 mm, a height of 123.5 mm, and a wall thickness of 0.105 mm are formed by squeezing and ironing using a 3004 aluminum alloy material with an original plate thickness of 0.3 mm, and then printing and drying are performed. Forty-two vertical beads 9 described above were formed on the two-piece DI can, and the constricted portion 8 was formed. The minimum outer diameter (constriction diameter) of the constricted portion 8 is 63 mm (Comparative Example 1), 62 mm (Example 1), 60 mm (Example 2), 57 mm (Example 3), 53 mm (Comparative Example 2). Part 8 was visually evaluated. The results are shown in a chart in FIG.

In Comparative Example 1, the minimum outer diameter (constriction diameter) of the constricted portion 8 is 95.5% of the original diameter before processing, and the difference from the diameters of the upper cylindrical portion 6 and the lower cylindrical portion 7 described above is small. Yes, it did not appear that the constricted portion 8 was formed, and the impression of constriction was impossible (x). On the other hand, in Examples 1 to 3, the minimum outer diameter (constriction diameter) of the constricted portion 8 is in the range of 85% or more and 95% or less of the original diameter before processing, and is constricted. This can be clearly seen, and in particular, the shape of Example 2 is the closest to the shape assumed in the design, and therefore the impression of constriction for each of Examples 1 to 3 was acceptable (◯). In Comparative Example 2, the vertical beads 9 in the minimum outer diameter portion 8a become dense and the impression of the vertical beads 9 becomes too strong, and the printed pattern or the printed characters applied to the constricted portion 8 are deformed. As it became larger, it had a great influence on the design as a metal can 1, and therefore the impression of constriction was impossible (x). After all, if it is smaller than 85%, the printed characters or printed patterns applied to the body portion 2 (constricted portion 8) become difficult to see, and the visibility of printing deteriorates. Further, if the outer diameter is larger than 95%, the impression of the constriction of the body portion 2 is weakened, and it becomes difficult to impress the purchaser with the peculiarity of the shape.

<About the height (depth) of the vertical bead>
The height (depth) Hb of the vertical bead 9 is the dimension from the valley portion 9b to the ridge line 9a as described above, and is 0.3 mm at the smallest and 1.5 mm at the largest. The lowest portion is the so-called end portion on the upper cylindrical portion 6 side and the lower cylindrical portion 7 side, the highest portion is the portion of the minimum outer diameter portion 8a, and the height (depth) Hb of the vertical bead 9 is In this range, it gradually changes from the ends on the upper cylindrical portion 6 side and the lower cylindrical portion 7 side toward the portion of the minimum outer diameter portion 8a. The portion having the smallest height Hb of the vertical bead 9 is a portion corresponding to the end portion of the ridge line 9a as shown in FIGS. 5A and 5B. The ridge line 9a is a portion formed between the valley portions 9b by denting both sides to form the valley portion 9b, and when the valley portion 9b is recessed, the valley portions 9b are formed at the upper and lower ends of the figure. Along with molding (or being dragged), a dented portion is gradually formed. The portion where the contours of the recessed portions match or intersect is the ridge line 9a. As described above, there is a gradually recessed portion above or below the end of the ridge line 9a, but there is no ridge line 9a corresponding to the gradually recessed portion. Therefore, in the embodiment of the present invention, the vertical portion is used. The portion having the smallest height Hb of the bead 9 is a portion corresponding to the end portion of the ridge line 9a, and the height Hb of that portion is the smallest height. The height (depth) Hb of the vertical bead 9 is set in the above range based on the results of the following experiment. Forty-two vertical beads of equal pitch are formed in the DI can described above, and the bead depths are 0.2 mm (Comparative Example 3), 0.3 mm (Example 4), 0.6 mm (Example 5), 1 The bead finish was visually evaluated at 5.5 mm (Example 6) and 1.6 mm (Comparative Example 4). The results are shown in a chart in FIG.

In Comparative Example 3, the depth of the vertical bead is out of the above range, and the bead shape at the end of the upper cylindrical portion 6 side and the lower cylindrical portion 7 side cannot be clearly visually recognized, and it may be a molding defect. It was visible, and the impression of the bead finish was impossible (x). On the other hand, in Examples 4 to 6, the bead depth is within the above range, and the vertical bead 9 can be clearly seen as a whole including the upper and lower ends thereof. The impression of the finish was acceptable (○). In Comparative Example 4, the bead depth is outside the above range and is excessively deep, and the bead depth is deep at the most constricted portion, so that the printed pattern or the printed character is excessively folded. This makes the print design difficult to see. Therefore, the impression of the bead finish in Comparative Example 4 was not possible (x). After all, the height Hb of the vertical bead 9 is set to 0.3 mm or more and 1.5 mm or less. By doing so, the portion where the height of the vertical bead 9 is the lowest is the portion on the upper cylindrical portion 6 side and the lower cylindrical portion 7 side described above, and the height Hb of this portion is at least 0.3 mm. Therefore, the vertical bead 9 can be clearly visible. Further, since the maximum height of the vertical bead 9 is 1.5 mm or less, the material of the body 2 is not excessively deformed or pulled while the clarity of the vertical bead 9 is ensured. The constricted portion 8 and the vertical bead 9 can be processed without causing damage such as cracks or breaks in the constricted portion 8), and the metal can 1 having good manufacturability can be obtained. Further, the position where the height Hb of the vertical bead 9 is the highest is the position of the minimum outer diameter portion 8a described above. Therefore, the vertical bead 9 absorbs the decrease in the surplus wall or the outer diameter in the place where the amount of constriction is large, and is unnecessary. It becomes a metal can 1 without wrinkles or deformation of beads.

<About the pitch and number of vertical beads>
Since the outer diameter of the body portion 2 or the constricted portion 8 is determined as described above, if the pitch P of the vertical beads 9 is widened, the number of vertical beads 9 is reduced, and conversely, the number of vertical beads 9 is narrowed. Can be increased. Therefore, in the embodiment of the present invention, the pitch P of the vertical bead 9 is 3.5 mm or more and 5.5 mm or less. This is based on the results of the following experiments. The pitch P of the vertical beads 9 formed in the constricted portion 8 of the DI can described above is 3.3 mm (number 63: Comparative Example 5), 3.5 mm (number 59: Example 7), 4.9 mm (number 42:). Example 8) was set to 5.5 mm (number 38: Example 9) and 5.7 mm (number 36: Comparative Example 6), and the finish of the bead was visually evaluated. The results are shown in a chart in FIG.

In Comparative Example 5, the vertical bead 9 is fine, the vertical bead 9 is difficult to see, and the impression of the vertical bead 9 is diminished. Further, since the vertical bead 9 becomes a thin convex portion, the height (depth) Hb of the vertical bead 9 cannot be increased, and if it is intentionally increased, the possibility of breakage or cracking increases. Therefore, as the pitch P is narrow, the height Hb of the vertical bead 9 becomes lower and the folding amount (absorption amount of surplus meat) of the wall portion becomes smaller, so that the minimum outer diameter of the constricted portion 8 can be reduced. It becomes difficult and the impression of constriction (shape specificity) becomes poor. Therefore, when the pitch P is 3.5 mm, the impression of bead finish is not possible (x). On the other hand, in Examples 7 to 9, the pitch P is in the range of 3.5 mm or more and 5.5 mm or less, the bead can be clearly seen, and the minimum outer diameter of the constricted portion 8 is required. It can be small enough. Therefore, the impression of the bead finish was acceptable (○). In Comparative Example 6, the pitch P of the vertical bead 9 is wide, and therefore the height (depth) Hb of the vertical bead 9 becomes large, and the impression of the vertical bead 9 becomes rough and has a strong “rugged” feeling. The impression of the bead finish was not possible (x). When the pitch P of the vertical bead 9 is widened and the height (depth) Hb is reduced, the cross-sectional shape of the bead becomes a so-called divergent shape, and the bead or the ridgeline becomes blurred.

In the metal can 1 according to the embodiment of the present invention described above, as described above, a clear vertical bead 9 and a constricted portion 8 can be formed, and the metal can can attract the attention of the purchaser with a favorable impression. Not only that, but also the minimum outer diameter of the constricted portion 8 can be made sufficiently small, so that the finger holding the metal can 1 can be prevented or suppressed from slipping in the vertical direction, and the bead is vertical. Since the bead 9 is formed over the entire circumference, it is possible to prevent or suppress the finger from slipping in the circumferential direction. That is, even if the metal can 1 is wet, it can be reliably grasped, and the metal can can be easily held. Further, since the vertical beads 9 are formed at substantially equal intervals on the entire circumference, the metal can 1 has no directionality because it looks almost the same shape when viewed from any position in the circumferential direction. It is not necessary to adjust the orientation of the metal can 1 at the time of display, and in that respect, the manufacturability or handleability is improved. Further, the finger holding the metal can 1 comes into contact with the ridgeline of the vertical bead 9, and since the contact area is small, the heat of the finger is not easily transferred to the metal can 1, and the heat of the contents is transmitted to the finger. It is difficult, and therefore it is possible to prevent or suppress situations such as the contents becoming warm or the fingers becoming hot.

FIG. 8 shows the results of the sensory test of ease of grip and heat. The number of vertical beads 9 is 42, the minimum outer diameter of the constricted portion 8 is 58 mm, and the maximum height (depth) of the vertical beads 9 is shown. ) Is 1.1 mm, and the results are shown for an example (bead can) in which other conditions are the same as those of the metal can 1 described above, and a normal can in which the constricted portion 8 and the vertical bead 9 are not formed.

Regarding the bead can, which is an example of the present invention, all 10 monitors recognized that it was easier to hold than a normal can. In addition, nine monitors confirmed that the bead cans relieved the heat.

Then, according to the metal can 1 described above, even when the barcode bars are printed on the constricted portion 8 so as to be aligned in the direction parallel to the central axis of the body portion 2, the distance between the bars is particularly large. Does not change, so it can be a metal can that does not interfere with the reading of barcodes. Further, in the metal can 1 described above, not only the constricted portion 8 is formed on the body portion 2, but also a large number of vertical beads 9 are formed on the constricted portion 8, which accompanies the formation of the constricted portion 8. The decrease in buckling strength is suppressed by the vertical bead 9.

Next, the method for manufacturing the metal can 1 described above will be described. FIG. 9 shows the process of changing the shape when the method of the embodiment of the present invention is carried out, and by drawing and ironing a blank (thin metal plate) (not shown), the rough shape shown in FIG. 9 (a) is shown. Material 10A is prepared. Further, the bottom portion 3 is subjected to a doming process. The squeezing process and the doming process may be conventionally known methods. Then, printing 11 is applied to the surface of the rough shape material 10A to obtain a print rough shape material 10B (see (b) in FIG. 9). The printing method may be a conventionally known method. In the case of a three-piece can, a printed metal plate is formed and welded into a cylindrical shape, and a lid is attached to one of the open ends to obtain a rough print material.

The body 2 of the rough printed material 10B is beaded leaving the upper cylindrical portion 6 and the lower cylindrical portion 7 to obtain the bead rough material 10C shown in FIG. 9 (c). In the bead processing, as shown in FIGS. 10 and 11, the core 12 is inserted into the rough printing material 10B, and in that state, the rough printing material 10B is pressed against the outer mold 13 by the core 12, and the core 12 and The rough printing material 10B and the outer mold 13 are rotated while being relatively moved with respect to at least one of them.

FIG. 12 shows an example of the core 12, and the core 12 is the inner diameter of the rough print material 10B (the inner diameter of the upper cylindrical portion 6 and the lower cylindrical portion 7 described above) so that the core 12 can be inserted into the rough print material 10B. ), And has a substantially drum shape having a constricted portion 12a having a shape corresponding to the constricted portion 8 to be applied to the metal can 1. Both the upper and lower portions of the constricted portion 12a have a cylindrical shaft shape or a cylindrical shaft shape. The constricted portion 12a is formed with a plurality of concave portions 12b and a plurality of convex portions 12c for forming the vertical bead 9 described above.

The concave portion 12b is for forming the valley portion 9b of the vertical bead 9, and the convex portion 12c is for forming the ridge line 9a between the vertical beads 9. The concave portion 12b and the convex portion 12c are linear in the direction parallel to the central axis of the core 12. Further, the ridge portion 12c has an arc shape that is smoothly recessed toward the center of the core 12 in the radial direction of the core 12. The arc shape is substantially the same as the shape of the vertical bead 9 to be formed on the metal can 1. By setting the bottom of the concave portion 12b at a position of a constant radius of the core 12, the height of the convex portion 12c is high on the upper end side and the lower end side in the central axis direction, and the above-mentioned minimum outer diameter portion 8a It is the lowest at the position corresponding to.

Therefore, the pitch that is the distance between the concave portions 12b or the pitch that is the distance between the convex portions 12c matches the pitch P of the vertical beads 9 to be formed in the metal can 1. On the other hand, since the core 12 has an outer diameter that can be inserted into the rough printing material 10B and is smaller than the outer diameter of the rough printing material 10B, the number of the concave portions 12b and the convex portions 12c is metal. The number is less than the number of vertical beads 9 to be formed in the can 1. In the embodiment of the present invention, the number of the concave portions 12b and the convex portions 12c in the core 12 is 60% or more and 70% or less of the number of the vertical beads 9 to be formed in the metal can 1. If it is less than 60%, the core 12 becomes thin, and in the so-called cantilever shape in which the core 12 is rotatably supported on only one side in the axial direction, the rigidity of the core 12 is insufficient and the pitch P of the vertical bead 9 is deviated. May occur. On the other hand, if it is more than 70%, the core 12 becomes thicker, and there is a high possibility that it becomes difficult to remove the core 12 from the metal can 1 in the state where the constricted portion 8 is formed.

The outer mold 13 includes a flat plate-shaped substrate portion 13a, and the recessed groove portions 13c, which are portions between the plurality of rib portions 13b and the rib portions 13b, are provided on the surface of the substrate portion 13a facing the core 12 at regular intervals. It is formed in parallel. The rib portion 13b is for forming the portion of the valley portion 9b in the vertical bead 9, and is configured so that the tip portion is inserted into the concave portion 12b in the core 12 described above. Further, the concave groove portion 13c is a relief groove for forming the ridge line 9a in the vertical bead 9, and is configured so that the tip end portion of the ridge portion 12c in the core 12 described above can be inserted. The rib portion 13b and the concave groove portion 13c are configured to form the above-mentioned vertical bead 9 and at the same time form the constricted portion 8. That is, the rib portion 13b and the concave groove portion 13c are linear in the vertical direction of the substrate portion 13a, and the thickness direction of the substrate portion 13a (the direction perpendicular to the surface facing the core 12 side) is shown in FIG. As shown in 13, the arc shape substantially matches the arc shape of the constricted portion 8 to be formed in the metal can 1. The height of the rib portion 13b (the dimension from the bottom of the concave groove portion 13c to the ridgeline of the rib portion 13b) is low on the upper end side and the lower end side of the vertical bead 9, and is the highest at the portion corresponding to the minimum outer diameter portion 8a. It gradually changes in the vertical direction so that it becomes higher.

The pitch of each rib portion 13b and each concave groove portion 13c coincides with the pitch P of the vertical bead 9 to be formed in the metal can 1. Further, the number of each rib portion 13b and each concave groove portion 13c is larger than the number of vertical beads 9 to be formed in the metal can 1. In order to make the shape of one or several vertical beads 9 formed first when the rough printing material 10B is pressed against the outer mold 13, these vertical beads 9 are combined with the outer mold 13 and the core 12. It is preferable to perform the molding process twice. Therefore, in order to rotate the rough printing material 10B by one rotation or more with respect to the outer mold 13 and to form the vertical bead 9 in the meantime, the number of each rib portion 13b and each concave groove portion 13c is added to the metal can 1. The number is larger than the number of vertical beads 9 to be formed. The number of vertical beads larger than 9 is about 1 to 4, and more preferably 2.

The core 12 is inserted into the rough printing material 10B, the core 12 is brought close to the outer mold 13, and the outer peripheral wall of the rough printing material 10B is sandwiched between the core 12 and the outer mold 13. In that case, in addition to bringing the core 12 closer to the outer mold 13, the outer mold 13 may be brought closer to the core 12. With the rough print material 10B sandwiched between the core 12 and the outer mold 13, the core 12 and the outer mold 13 are moved relative to the central axis of the core 12. Such relative movement may be performed by moving the core 12 along the outer mold 13, or simply holding the core 12 rotatably and moving the outer mold 13 in the direction of the arrow in FIG. It may be done by moving to.

The relative distance between the core 12 and the outer mold 13 is the distance at which the concave portion 12b and the convex portion 12c in the core 12 and the rib portion 13b and the concave groove portion 13c in the outer mold 13 mesh with each other. Therefore, by moving the core 12 and the outer mold 13 relative to each other as described above, the core 12 and the rough print material 10B rotate while moving along the outer mold 13. As described above, the rib portion 13b provided on the outer mold 13 projects in an arc shape toward the core 12, so that the body portion of the rough print material 10B is inward as shown in FIG. It is recessed and the constricted portion 8 is formed. Further, since the concave portion 12b and the convex portion 12c of the core 12 and the rib portion 13b and the concave groove portion 13c of the outer mold 13 are sequentially meshed with each other, the vertical bead 9 is formed in the constricted portion 8.

The vertical bead 9 has a shape corresponding to the shape and meshing depth of the concave portion 12b and the convex portion 12c of the core 12 and the rib portion 13b and the concave groove portion 13c of the outer mold 13. FIG. 15 shows the meshing state of the concave portion 12b and the convex portion 12c in the core 12 on the upper end side or the lower end side of the constricted portion 8 and the rib portion 13b and the concave groove portion 13c in the outer mold 13, and FIG. 16 shows the constricted state. It shows the meshing state of the concave portion 12b and the convex portion 12c in the core 12 in the minimum outer diameter portion 8a in the portion 8 or in the vicinity thereof and the rib portion 13b and the concave groove portion 13c in the outer mold 13. As shown in FIGS. 15 and 16, at the upper end and the lower end of the vertical bead 9, the concave portion 12b and the convex portion 12c of the core 12 and the rib portion 13b and the concave groove portion 13c of the outer mold 13 are engaged with each other. The depth is shallow, and in the minimum outer diameter portion 8a of the constricted portion 8 or its vicinity, the meshing depth between the concave portion 12b and the convex portion 12c in the core 12 and the rib portion 13b and the concave groove portion 13c in the outer mold 13 is large. Get deeper. Therefore, in the minimum outer diameter portion 8a or its vicinity, the amount of folding as the vertical bead 9 increases, so that the vertical bead 9 absorbs the surplus portion or the surplus thickness of the peripheral wall portion due to the reduction in the outer diameter of the body portion. , The amount of absorption becomes the amount corresponding to the decrease of the outer diameter. As a result, the constricted portion 8 and the vertical bead 9 can be formed at the same time without causing deformation of the vertical bead 9 or abnormal shape such as wrinkles. The cross-sectional shape of the ridge line 9a in the vertical bead 9 has a rounded shape that follows the cross-sectional shape of the tip of the convex portion 12c in the core 12, and the cross-sectional shape of the valley portion 9b is The outer mold 13 has a rounded shape that follows the cross-sectional shape of the tip portion of the rib portion 13b.

The core 12 is formed to have an outer diameter smaller than the outer diameter of the rough material 10A to 10C or the metal can 1 in order to be taken in and out of the rough material 10A to 10C or the metal can 1, and therefore the core 12 rotates one or more turns. By relatively moving the core 12 and the outer mold 13 in this way, the constricted portion 8 and the vertical bead 9 are formed over the entire outer circumference of the metal can 1. In the embodiment of the present invention, the relative moving distance is longer than the outer peripheral length of the metal can 1. Specifically, it is a distance at which several (for example, two) of the vertically formed vertical beads 9 can be re-engaged between the core 12 and the outer mold 13 at the end of the relative movement. .. As a result, the number of vertical beads 9 determined by design can be formed, and the shape of several vertical beads 9 initially formed can be adjusted. Further, since the number of vertical beads 9 to be reprocessed at the final stage is not particularly large, even if there is a slight slip between the core 12 in the process of processing and the rough printing material 10B, the vertically formed vertical bead 9 is formed at the initial stage. The pitch deviation between the bead 9 and the rib portion 13b or the concave groove portion 13c of the outer mold 13 is slightly reduced, and the vertical bead 9 can be accurately formed.

The bead rough shape member 10C shown in FIG. 9C is subjected to neck-in processing and flange forming processing. The neck-in processing is a processing for forming a taper so that the outer diameter gradually decreases on the upper end side, and the flange forming processing is a processing for forming a flange portion 4 for attaching a lid (not shown). Can also be processed by a conventionally known method. FIG. 9D shows the metal can 1 obtained by performing these processes.

In the method according to the embodiment of the present invention described above, the body 2 of the metal can 1 is squeezed so that the outer diameter is small, and at the same time, the constricted portion 8 and the vertical bead 9 are formed by bending (or folding) the metal can 1 into irregularities at a constant pitch. Therefore, the coating film on the inner surface and the outer surface of the metal can 1 is hardly damaged. Therefore, it is possible to improve the manufacturability by omitting processing such as repairing the coating film. Further, since the molding of the constricted portion 8 and the molding of the vertical bead 9 can be performed at the same time, the number of steps is reduced and the number of molds to be used is reduced, so that the manufacturability can be improved in this respect as well. Further, by changing the mold in the conventional bead molding apparatus to the core 12 and the outer mold 13 described above, the metal can 1 described above can be molded, which simplifies the equipment and reduces the manufacturing cost. it can.

1 ... metal can, 2 ... body, 6 ... upper cylinder, 7 ... lower cylinder, 8 ... constriction, 9 ... vertical bead, 9a ... ridge, 8a ... minimum outer diameter, 9b ... valley, Hb ... Height (of vertical bead), H ... Height (of metal can), Dmin ... Outer diameter (of minimum outer diameter), D0 ... Outer diameter (of upper cylinder and lower cylinder), 12 ... Core, 13 ... outer mold, 12b ... concave portion, 12c ... convex portion, 13a ... substrate portion, 13b ... rib portion, 13c ... concave groove portion, L ... (constricted portion) length.

Claims (4)

In a metal can whose body is formed into a tubular shape by a thin metal plate
The height is 80 mm or more and 170 mm or less,
The thickness of the body is 0.1 mm or more and 0.25 mm or less.
The upper end portion and the lower end portion of the body portion are formed into an upper cylindrical portion and a lower cylindrical portion having a cylindrical shape and an outer diameter of 50 mm or more and 70 mm or less, respectively.
2. In the intermediate portion between the upper cylindrical portion and the lower cylindrical portion, a plurality of linear vertical beads extending in the central axis direction of the body portion and protruding outward in the radial direction of the body portion are formed. It is formed over the entire circumference of the intermediate portion at a pitch of 5 mm or more and 5.5 mm or less.
In the intermediate portion, the ridgeline of the vertical bead extends in the radial direction of the body portion from the upper cylindrical portion and the lower cylindrical portion to the portion between these cylindrical portions over the entire circumference of the intermediate portion. It is constricted so as to form an arc shape that is gradually curved inward, and the length of the confined portion in the direction of the central axis of the body is 40 mm or more and 120 mm or less.
The most constricted portion of the intermediate portion is the minimum outer diameter portion, and the outer diameter of the minimum outer diameter portion is 85% or more and 95% or less of the outer diameter of the upper cylindrical portion or the lower cylindrical portion. And
The longitudinal bead portion between the ridges of the longitudinal beads adjacent is a valley, the highest in the bead height is pre SL minimum outer diameter which is dimensioned to the ridge from valley, and the upper cylindrical It is characterized in that the height is gradually lowered on the portion side and the lower cylindrical portion side, the highest height is 1.5 mm or less, and the lowest height gradually lowered is 0.3 mm or more. Metal can.

In the method for manufacturing a metal can gradually smaller constricted portion outer diameter to a cylindrical barrel made of a thin metal plate is made form the entire circumference,
A plurality of concave portions extending in a direction parallel to the rotation center axis and retreating in a radial direction perpendicular to the rotation center axis so that the outer diameter gradually decreases in the middle portion in the rotation center axis direction. Insert the core in which the ridge and the ridge are formed into the inside of the body,
It has a rib portion that bites into the concave portion and a concave groove portion that bites the convex portion, and the rib portion and the concave groove portion are formed in the radial direction of the concave portion and the convex portion. While the body is pressed by the core against the outer mold protruding toward the core so as to have a shape that matches the retreat, the body is relatively moved along the outer mold together with the core. It is dynamic and is rotated once or more rotating,
The concave portion and the longitudinal beads extending in the center axis direction of kidou portion before the entire circumference of the body portion is formed with the convex portion and the rib portion and the concave groove portion by the mesh with each other, and The meshing depth between the concave portion and the rib portion and the meshing depth between the convex portion and the concave groove portion are the positions where the concave portion and the convex portion are most retracted in the radial direction. A method for producing a metal can, characterized in that the vertical bead and the constricted portion, whose height gradually changes, are simultaneously molded by making the vertical bead deeper and shallower as the distance from the portion increases. In the method for manufacturing a metal can according to claim 2.
The number of the rib portion and the concave groove portion provided on the outer mold is larger than the number of the vertical beads formed on the body portion.
Method for producing a metal can, characterized in that the moving distance along the outer die before kidou portion inserting said core greater than the length of the outer circumference of the barrel. In the method for manufacturing a metal can according to claim 2 or 3.
The number of the convex portion and the concave portion provided on the core is 60% or more and 70% or less of the number of the vertical beads formed on the body portion.
A method for producing a metal can, which comprises rotating the core more than one rotation to form the vertical bead.

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