JPH0651211B2 - Can barrel manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of manufacturing a can body used for a beverage can or the like having an inclined portion at an opening end.

(Prior Art) In recent years, deformed cans have been widely used in metal beverage cans and the like due to diversification of hobbies.

As a type of such, a two-piece deformed can is known which is provided with a smooth inclined portion in which the diameter of the can body gradually decreases toward the opening of the can body. As shown in FIG. 4A, as a method for manufacturing this two-piece deformed can, as shown in FIG. 4A, a step portion is formed by narrowing the opening b side of the can body a. A plurality of small-diameter portions d having c are formed, and then a processing roll e is brought into contact with the outside of the opening b of the can body a so that the step c and the small-diameter portion d of the can body a are formed by the processing roll e. Push it inward, and as shown in FIG.
A method of forming the is proposed.

However, in the case of such a manufacturing method, the step c and the small diameter part d on the opening b side of the can body a are processed by the processing roll e.
When the inclined portion f is formed by pressing with, the opening diameter h of the end portion g connected to the inclined portion f is reduced inward of the can body a by the pressing force of the processing roll e. That is, the multi-stage small-diameter portion d is flattened and the opening diameter h of the opening b of the can body a is also reduced.
The end portion g of the can body a is reduced in diameter, and the step portion c and the small diameter portion d are formed.
In order to perform processing such that the processing roll e is pressed to form an inclination, the processing roll e requires a large pressing force, and the processing roll e also needs a complicated movement. Therefore, the apparatus becomes complicated, and there is a problem that the sharp pressing process causes wrinkles on the inclined portion f and the opening end of the can body a to deteriorate the appearance. In particular, when the can body material is hard and drawability is poor, or when the amount of work deformation is large, wrinkles are prominent.

In order to avoid such a wrinkle caused by a sudden and large pressing force, it is necessary to apply a very large pressing force very gradually, and there is a disadvantage that the manufacturing efficiency is extremely lowered.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems and provides an open end portion of a bottomed tubular can body for a two-piece can or for a three-piece can in which one open end is closed. An object of the present invention is to provide a method for efficiently manufacturing a can body having a smooth sloped portion without causing wrinkles.

(Means for Solving the Problems) The present invention has been made to solve the above problems, and a can is provided at the opening end of a bottomed tubular can body toward the opening end of the can body. In a method of forming a continuous inclined portion in which the barrel diameter becomes gradually smaller, there are a plurality of intervals at the opening end of the can barrel from the center side of the can barrel to the opening end side, and a plurality of times in order from the opening end side. Are narrowed down to form a plurality of small-diameter portions each having a step portion with a diameter smaller than the diameter of the adjacent narrowing portion from the center side of the can body toward the opening end side, and then formed at the opening end portion. It is characterized in that the small diameter portion having the stepped portion is pressed by the roll from the inner and outer surfaces of the can body to form a flat inclined portion.

EXAMPLES The present invention will be described below with reference to the drawings.

FIGS. 1A to 1G show an example of a method for manufacturing a can body according to the present invention, and in this embodiment, the can body diameter gradually decreases toward the open end side of the can body (1) as shown in FIG. This shows a method of forming a continuous inclined portion (10) that becomes

Further, the can body (1) used in this embodiment is for a conventionally used two-piece can having the same can body diameter W from the opening end side to the bottom part (3) side before being narrowed down as shown in FIG. 1A. It is a can body.

First, as shown in FIG. 1B, the body part (4) of the can body (1) is held by the turret feeder (25), and the bottom part (3) is held by the holding part (27) of the holding device (26). The open end portion (2) of the can body (1) is advanced toward the outer die (16) side of the first narrowing device (11), and the first narrowing device (1)
The open end portion (2) of the can body (1) is fitted to the holding surface (19) of the guide portion (18) of (1). Next, the can body (1) is advanced toward the inner die (17) side of the first narrowing device (11) to insert the inner die (17) into the open end portion (2) of the can body (1). And again, the outer die (1
When the can body (1) is advanced to the 6) side, the open end (2) of the can body (1)
Along the step forming surface (22) of the outer mold (16) and then along the inner peripheral surface (21) of the molding part (20) of the outer mold (16) with the inner peripheral surface (21) and the inner mold ( 1
The end (24) of the gap (24) formed by the outer periphery (23) of (7)
a), which results in a length L ₁ as shown in the second illustration
The first small diameter portion (6) having the stepped portion (5) is formed with the diameter W ₁ smaller than the diameter W of the can body. The process of narrowing down the can body shown in FIG. 1B will be described with reference to FIG.

First, as shown in FIG. 5A, the can body (1) held by the holding device (26) is advanced to the outer mold (16) side to insert the inner mold (17) into the can body (1). After that, the inner mold (17) is moved to the outer mold (16) side to a predetermined position at a speed higher than the moving speed of the can body (1) to the outer mold (16) side.

Next, as shown in FIG. 5B, when the can body (1) advances toward the outer mold (16) side, the tip of the open end (2) of the can body (1) forms a stepped portion of the outer mold (16). Contact surface (22).

Then, as shown in FIG. 5C, the can body (1) is advanced toward the outer mold (16) side so that the open end (2) of the can body (1) contacts the step forming surface (22). It has been narrowed down and its tip is the end (24a) of the gap (24).
To contact.

Next, as shown in FIG. 5D, the can body (1) is advanced to the outer mold (16) side so that the tip of the open end (2) of the can body (1) is the outer mold (16) and the inner mold. (1
It is bent back in the gap (24) between the
In step (2), a step (5) is formed at the open end (2) of the can body (1).

Then, as shown in FIG. 5E, the can body (1) is further advanced to the outer mold (16) side, and the can body is moved by the gap (24) between the outer mold (16) and the inner mold (17).
A can body W ₁ having a length L ₁ as shown in the second illustration and a diameter smaller than the body diameter W is formed by straightening the tip end of the opening end (2) of (1) and completing the narrowing process. Thus, the first small diameter portion (6) having the step portion (5) is formed.

Next, as shown in FIG. 1C, the body portion (4) of the can body (1) having the first small diameter portion (6) formed at the opening end portion (2) in the previous step is held by the turret feeder (30). The bottom part (3) of the holding device (41).
The opening end portion (2) of the can body (1) held by (42) is a second narrowing device.
It is advanced to the outer mold (31) side of (12), and the holding surface (34) of the guide portion (33) of the second narrowing device (12) is moved to the opening end portion (2) of the can body (1). 1 Fit the small diameter part (6). Next, the inner type of the first narrowing device (11)
A can body on the inner die (32) side of the second narrowing device (12) having a smaller diameter than (17).
(1) is advanced to insert the inner mold (32) into the open end (2) of the can body (1). And again the outer mold (31) of the second narrowing device (12)
When the can body (1) is advanced to the side, the open end (2) of the can body (1) follows the step forming surface (37) of the outer mold (31), and then the outer mold (31) is formed. Along the inner peripheral surface (36) of the part (35), the inner peripheral surface (36) and the inner mold (3
The end (39) of the gap (39) formed between the outer peripheral surface (38) of (2)
Proceed to a), which allows the can body (1) as shown in Figure 2.
The first small-diameter portion (6) to the second small-diameter portion having stepped portions at the small diameter of the trunk diameter W ₂ than and the distance to the opening end side is to the length L ₂ exist first small diameter portion (6) to (5) of (7) is formed. The process of narrowing down the can body (1) shown in FIG. 1C is performed in accordance with the process of narrowing down the can body shown in FIG.

Then, as shown in FIG. 1D, the first step is performed on the opening end (2) in the previous step.
The barrel portion (4) of the can barrel (1) having the small diameter portion (6) and the second small diameter portion (7) is held by the turret feeder (50), and the bottom portion (3) is held by the holding device (61). The open end portion (2) of the can body (1) held by the holding portion (62) is advanced to the outer die (51) side of the third narrowing device (13),
The can body (1) is attached to the holding surface (54) of the guide portion (53) of the third narrowing device (13).
The second small-diameter portion (7) of the open end (2) is fitted. Next, the third narrowing device (1) having a smaller diameter than the inner die (32) of the second narrowing device (12).
Move the can body (1) to the inner mold (52) side of (3) to move the inner mold (52)
Insert it into the open end (2) of (1). When the can body (1) is advanced to the outer die (51) side of the third narrowing device (13) again, the open end portion (2) of the can body (1) forms a stepped portion of the outer die (51). The inner peripheral surface (56), the inner mold (52) and the outer peripheral surface (58) along the inner peripheral surface (56) of the molding portion (55) of the outer mold (51) along the surface (57). It is advanced to the end (59a) of the gap (59) formed by the above, and as a result, the second small diameter part (7) of the can body (1) as shown in the second figure is extended to the open end side with a space. A third small diameter portion (8) having a step portion (5) is formed with a body diameter W ₃ having a length L ₃ and a diameter smaller than that of the second small diameter portion (7).
The narrowing process of the can body (1) shown in FIG.
The process is performed according to the process of narrowing down the can body shown in the figure.

Through the above steps, a plurality of small diameter parts (9) having stepped parts (5) are formed at the open end part (2) of the can body (1) as shown in the second illustration, and the inclined part (10) described below is formed. A can body (1) having a body diameter W _{3 of a} third small diameter portion (8) having the same diameter as the opening diameter W _X of the predetermined opening end at that time is manufactured.

In order to form a smooth sloped portion (10) at the open end (2) of the can body (1) as shown in FIG. 3, first, as shown in FIG. 1E, the can body obtained in the previous step. The bottom part (3) of (1) is held by the holding part (77) of the holding device (76), and the opening end part (2) of the held can body (1) is provided with the inclined part forming surface (73). External type (72),
The roll forming device (71) including an inner mold (74) having a forming surface (75) having a shape corresponding to the inclined portion forming surface (73) of the outer mold (72) is moved forward to advance the roll forming device. The inner mold (74) of (71) is inserted into the open end (2) of the can body (1). Then the inner mold (7
4), the outer mold (72) is brought closer by an eccentric cam (not shown)
The inclined portion forming surface (73) of (72) is connected to the open end portion (2) of the multi-step small diameter portion.
Faced to (9) and sloped surface (75) of inner mold (74)
To face the multi-stage small diameter portion (9). Then, FIG. 1F
As shown, the outer die (72) and the inner die (74) of the roll forming apparatus (71) are brought close to each other. Then, as shown in FIG. 1G, when the holding device (76) is rotated, the outer mold (72) and the inner mold (74) are rotated together, and the outer mold is rotated.
Between the inclined part forming surface (73) of the (72) and the forming surface (75) of the inner mold (74), the multi-stage small diameter part (9) of the open end (2) of the can body (1) is entirely formed. It is pinched in sequence around the circumference, and has a predetermined opening diameter Wx at the open end of the can body (1) as shown in the third drawing, and the can body diameter goes from the center side of the can body (1) toward the open end side. To form a sloping portion (10) having a continuous length L _X with a gradually decreasing diameter.

Through the above steps, as shown in the third illustration, the open end of the can body (1)
A can body (1) having a sloped portion (10) formed on (2) is manufactured.

In this case, even if the difference between the can body diameter W and the opening diameter W _X at the opening end is remarkable, the roll forming device is formed from the inner and outer surfaces of the can body (1) after forming the multi-stage small diameter portion (9). The outer mold (72) and the inner mold (74) of (71) are pressed to form a flat sloped part (10), which is stiff and sharp even if a can body material with poor narrowing workability is used. Since no compressive strain is applied, wrinkles are not generated in the inclined portion (10) and the opening end, and the opening diameter W _X of the predetermined opening end is changed to the body diameter W ₃ of the small-diameter portion (9) formed in advance. It can be manufactured continuously and efficiently without any problems.

In the illustrated embodiment, the method of forming the inclined portion at the opening end of the can body for the two-piece can is shown, but at the other opening end of the can body for the three-piece can in which one opening end is closed in advance. Similar methods and devices can be applied in forming the ramps.

In each narrowing step of forming the small diameter portion (9) as in the above embodiment, By sequentially reducing the diameter reduction ratio before the narrowing step, it is not necessary to sequentially increase the narrowing molding pressure for forming the small diameter portion (9) at the opening end (2), and the step ( 5) Does not cause wrinkles.

In addition, the can body (1) obtained by this manufacturing method has an inclined portion (10).
Although the flange portion is formed on the edge of the opening end portion (2) subsequently, the conventional method and apparatus for forming the flange portion can be used.

(Effect of the invention) As described above, according to the present invention, there are a plurality of intervals at the opening end of the can body from the center side of the can body to the opening end side, and the narrowing processing is performed a plurality of times in the order farther from the opening end side. And a plurality of small-diameter portions each having a step portion having a diameter smaller than the diameter of the narrowing portion adjacent to each other from the center side of the can body toward the opening end side are formed, and the opening diameter of the opening end is set to the inclined portion. Two-piece by forming to a predetermined diameter when formed, and then forming a small-diameter portion having a step formed at the open end of the can body from the inner and outer surfaces of the can body by a roll to form a flat inclined portion A bottomed tubular can body for a can or for a three-piece can with one open end closed is manufactured. Therefore, first, a multi-stage small-diameter portion is formed at the open end of the can body, and then the multi-stage small-diameter portion is pressed from the inner and outer surfaces of the can body to form an inclined portion. Even if the difference from the opening diameter is significant, there is an effect that a can barrel having a predetermined opening diameter and having no wrinkles on the inclined portion or the opening end and having an excellent appearance can be continuously and efficiently manufactured.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an example of the manufacturing method of the present invention, and FIG. 2 is a cutaway side view showing an example of a can body in the middle of the manufacturing method of FIGS. 1A to 1D. FIG. 4 is a side view of a can of the can body obtained by the manufacturing method of FIG. 1, showing a cut side view, FIG. 4 is a side view of a part of the can body of a conventional example, and FIG. It is a schematic diagram for explaining a narrowing processing step to the opening end. (1) …… Can barrel (2) …… Opening end (5) …… Step (9) …… Small diameter part (10) …… Inclined part

Claims (1)

[Claims] 1. A method of forming a continuous inclined portion in which the diameter of the can body gradually decreases toward the opening end side of the can body at the opening end of the bottomed tubular can body, the opening end of the can body. There are multiple intervals from the center side of the can body to the opening end side, and the narrowing processing is performed multiple times in the order distant from the opening end side to narrow down adjacent to each other from the center side of the can body toward the opening end side. A plurality of small-diameter portions each having a step portion having a diameter smaller than the body diameter, and then the small-diameter portion having a step portion formed at the opening end is pressed from the inner and outer surfaces of the can body by a roll to form a flat inclined portion. A method for manufacturing a can body, which comprises forming.