JPS6235849B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a double seaming method, and more particularly to a double seaming method in which the axial load applied to the can body is extremely small when forming the double seam portion.

In the conventional double seaming method, as shown in FIG.
After placing the curled part 4 (lid part or bottom part) and fitting the chuck 6 into the end member 3 having the recessed panel part 5, the can body 1 is placed with a lifter (not shown).
While supporting the lower part of the
The curled part 4 and the flange part 2 are pressed between the first seaming roll 7 and the chuck 6, and the end 4a of the curled part is directed upward, and the preliminary winding is inserted into the inside of the downwardly directed flange part 2. forming a tightening part 8;
Subsequently, by the second seaming roll 9, a portion 4a' corresponding to the curled portion end 4a (usually called a cover hook) and a portion 2' corresponding to the flange portion 2 (usually called a body hook) are sealed with a sealing member (not shown). This is done by forming a double seam 10, shown in FIG. 1c, in close contact with the compound. Incidentally, the bent portion 11 at the upper end of the body hook 2' is usually called the body hook radius.

As described above, in the conventional double seaming method, especially in the step of forming the preliminary seaming part 8, the axial component force applied to the flange part is supported, and the flange part 2
In order to prevent the escape of the body hook 2' and to ensure the specified length of the body
120 to 200 kg) must be added to the can body 1 using a lifter. Therefore, if the conventional double seaming method is applied to a can body made of a material with low axial load resistance, the can body will not sit properly. I can't give in and get a satisfactory product. Therefore, the thickness of the can body is
Due to constraints from the axial load applied during double seaming, a predetermined value (for example, in the case of steel such as tinned steel plate, approx.
0.10mm, approximately 0.13mm for aluminum alloy) (even if it is thinner than the specified value above, for example, in the case of a sealed can with internal pressure higher than atmospheric pressure, problems such as deformation due to external pressure such as impact will not occur). Therefore, it has been difficult to reduce costs by reducing the thickness of the can body. For the same reason, it has been difficult to apply the conventional double seaming method to can bodies made of relatively thin plastic, paper, or laminates thereof (including laminates with metal foil). Therefore, although the double-sealed part has the advantage of superior reliability in airtightness, the conventional double-sealed method cannot form the part of the can body mentioned above. The problem was that it was difficult.

The present invention aims to solve the problems of the prior art described above.

To achieve the above object, the present invention comprises a can body having a cylindrical open end, a panel part, and a side wall, the side wall comprising a bent part and a hanging part connected to the upper end of the main part of the side wall. A method of double-sealing an end member having an outwardly curled portion with a gap width approximately equal to the wall thickness of the opening end, the method comprising: inserting the opening end into the curling portion and tightening the opening. The end part and the main part of the side wall contact each other to form a double wall part, and the most protruding part of the spinning roll, which rotates around a vertical axis and has a dogleg shape with a circumferential surface convex outward in cross section, is the hanging part. pressing the double wall portion inward in the radial direction with the spinning roll so as to hit a slightly lower portion of the spinning roll;
A circumferential groove portion having a dogleg-shaped cross section consisting of a lower tapered portion that curves inward and extends obliquely upward from a position slightly above the panel portion, and an upper tapered portion that extends obliquely upwardly on the outside, leaving a short cylindrical portion. After forming the heavy wall portion by spinning, the inner surface of the short cylindrical portion of the double wall portion below the lower tapered portion and the lower surface of the lower tapered portion are supported by a rotating chuck. While pressing the outer surface of the short cylindrical part with a presser roll, the upper tapered part is pressed by a seaming roll rotating around a horizontal axis and having a pressing circumferential surface having an inclination corresponding to the lower tapered part. To provide a double seaming method characterized in that the hanging part is pressed downward by spinning until it comes into contact with the outer surface of the lower tapered part to form a double seaming part extending inward and obliquely upward. It is something.

The present invention will be described below with reference to drawings showing embodiments.

First, a panel portion 21 as shown in FIG. 2, a side wall main portion 22 vertically rising from the panel portion 21, and a side wall main portion 22 hanging down from the upper end of the side wall main portion 22 via a bent portion 23,
Cover hook (fifth
The hanging part 24 has a height equal to the length (see 68 in figure b).
(the outward curl portion 19 is formed by the bent portion 23 and the hanging portion 24), the outer diameter of the main side wall portion 22 is approximately equal to the inner diameter of the open end portion 26 of the can body 25, and the outer diameter of the main side wall portion 22 is approximately equal to the inner diameter of the open end 26 of the can body 25. An end member 27 (in the case of a three-piece can, an end member 27 including a side wall 18 having a gap width between the part 22 and the hanging part 24 that is approximately equal to the wall thickness of the open end 26 (the lid part and the bottom part in the case of a three-piece can)
In the case of a two-piece can, the lid is manufactured by a pressing method or the like.

The material of the end member 27 is a tin-plated steel plate, a sheet made of steel such as stain-free steel,
and metal plates such as aluminum (alloy) plates (including those with interlayers, printed films, etc. formed on the surface), or metal foils (in the case of steel or iron-based foils to ensure seaming strength) Thickness of approximately 20 μm or more,
A laminate of aluminum foil (preferably about 50 μm or more in thickness) and a plastic film or sheet is selected depending on the purpose of use.

Although not shown in FIG. 2, the hanging portion 24,
As shown in FIG. 3, a sealing compound layer 20 is usually formed on the bent portion 23 and the upper inner surface of the side wall main portion 22 to ensure sealing performance.

The can body 25 is made of a metal plate, a plastic sheet,
It is formed of a paper material (impregnated or coated with wax or plastic, etc.), or a laminate made of a suitable combination of a plastic sheet or film, paper material, and metal foil. Instead of using the aforementioned sealing compound, the inner and/or outer layer (not shown) of at least the open end 26 of the can body 25 and/or the inner layer of the end member can be used to ensure the airtightness of the double seam. and/or the outer layer (not shown) is formed of a heat-fusible plastic film (for example, acid-modified polyolefin resin), or a hot-melt adhesive is applied to the surface instead of the heat-fusible plastic film, After the open end portion 26 is fitted into the end member 27, or during or after double seaming, thermal fusion or thermal bonding may be performed.

Next, as shown in FIG. 2, the open end 26 of the can body is inserted into the gap between the side wall main part 22 and the hanging part 24 of the end member 27, that is, the curled part 19, so that the open end 26 and the side wall main part 22 are in contact with each other and form a double wall portion 28.
form. Next, a circumferential groove portion 29 having a dogleg-shaped cross section is formed in the double wall portion 28 using the apparatus A shown in FIG. 2 (see FIG. 3a).

The apparatus A includes a rotary chuck 30, a spinning roll 31 and a rotary support plate 32. The rotary chuck 30 includes a cylindrical sleeve 33 in which a tapered part 33a extending inwardly downward is formed at the lower part, a split mold 34, and a central shaft 3 for expanding the split mold 34.
5. A spring 36 is provided for contracting the split mold 34 when the central shaft 35 rises.

The split mold 34 is comprised of a plurality of split mold pieces 37, each of which has a vertical portion 38, a horizontal outer protrusion 39, and a lower inner tapered portion 40. Vertical section 38
The outer peripheral surface 38a has a shape corresponding to the inner peripheral surface 33b of the sleeve 33. As shown in FIG. 3, the lower portion 39a of the outer peripheral surface of the horizontal outer protrusion 39 has a straight cylindrical shape, and when the split mold 34 is expanded (the state shown in FIG. 2), the main portion of the side wall 22 of the end member 27 is Furthermore, as shown in FIG. 3a, the circumferential surface of the horizontal outer protrusion 39 has a taper extending inward and obliquely upward from the straight cylindrical outer circumferential lower part 39a. A portion 39b is formed, and when the split die 34 is expanded, it cooperates with the tapered portion 33a of the sleeve 33 to form a circumferential groove 41 having a dogleg-shaped cross section in the lower part of the rotary chuck 30. The upper surface 39c of the horizontal outer protrusion 39 is configured to be slidable on the bottom surface 33c of the sleeve 33.

The lower inner tapered portion 40 engages with the lower tapered portion 35a of the center shaft 35, and when the center shaft 35 descends, the split mold 34 expands, and when the center shaft 35 rises, the lower part of the vertical portion 38 of the split mold expands. The split mold 34 is configured to contract due to the action of a spring 36 surrounding it.

In order to move the center shaft 35 up and down, the center shaft 35
A roller 42 that engages with a circumferential groove 35b formed at the upper end, a lever 43 that pivotally supports the roller 42 at one end, a driven roller 44 that is pivotally supported at the other end of the lever 43, and a lever 44 that engages with the driven roller 44. , a cam 45 that can move the driven roller 44 up and down, and a spring 46 that engages the driven roller 44 with the cam 45. lever 43 and cam 4
5 is pivotally supported by a frame 47, and the central shaft 35 is vertically slidable along a bearing 48 provided on the frame 47. The sleeve 33 is pivotally supported by a fixed platen 49, and is rotated via gears 50 and 51 by a drive mechanism (not shown).

The spinning roll 31 is disposed at a position facing the circumferential groove 41 of the rotary chuck 30, and is moved toward and away from the circumferential groove 41 by a support 52 that supports the spinning roll 31 so as to rotate around a vertical axis. is now possible. The circumferential surface 31a of the spinning roll 31 is connected to the circumferential groove 4 of the rotating chuck 30.
It has a shape corresponding to 1. That is, the cross section has a dogleg shape with an outward convexity. The shaft 53 fixed to the rotary support plate 32 has a common axis with the central axis 35, and is rotatably supported by a vertically movable support (not shown).

Using the above-mentioned apparatus A, the double wall portion 28 is formed in the circumferential groove portion having a dogleg shape in cross section as follows.

First, in the position where the rotary support plate 32 is lowered,
The can body 25 having the double wall portion 28 formed between it and the end member 27 is placed on the rotary support plate 32 so that its axis coincides with the axis of the shaft 53.
Next, with the center shaft 35 raised and the split mold 34 contracted, and the spinning roll 31 separated, the rotary support plate 32 is raised, and the split mold 34 is retracted.
4, the end member 27 is brought into contact with the bottom surface of the split mold 34, and then the center shaft 35 is lowered, as shown in FIG.
expand.

Next, when the gear 50 is rotated to rotate the sleeve 33, the can body 25 also rotates together with the rotary support plate 32. The roll 31 is brought close to the rotating double wall portion 28, and as shown in FIG. Part 3
1b hits a portion slightly below the hanging portion 24, pressing the double wall portion 28, forming a circumferential groove portion 29 with a dogleg-shaped cross section in the double wall portion 28, leaving a short cylindrical portion 63;
Formed by spinning.

In order for the circumferential groove portion 29 to form a short cylindrical portion 63,
A predetermined point P located slightly above the panel part 21 and below the position where the lower end 70 of the double seaming part 56 (see FIG. 5b) is to be formed.
A lower tapered portion 5 extending inwardly and obliquely upward from the starting point.
4 and the body foot radius 7 of the double seam portion 56
1 (corresponding to the upper end of the lower tapered part 54) and extends outward and obliquely upward. The height of the outer protrusion 39 and the lower end 39 of the tapered portion 39b
The position of b′ is determined.

After the circumferential groove portion 29 is formed as described above, the rotation of the sleeve 33 is stopped, the spinning roll 31 is separated, and the rotation of the cam 45 causes the center shaft 35 to rise and the split mold 34 to contract, and to protrude horizontally outward. The lower portion 39a of the outer circumferential surface of the portion 39 is the shortest inner diameter portion of the circumferential groove portion 29.
It moves inward from Q' (that is, the inner side of the side wall main portion 22 deformed into a dogleg shape at position Q).
After that, the rotary support plate 32 is lowered.

Next, as shown in FIG.
b' and the tapered part 33'a of the sleeve 33' have a larger slope than the tapered part 39b and the tapered part 33'a of the device A (preferably the tapered part 3
The angle θ between 9′b and tapered portion 33′a is approximately 90
degree), that is, the circumferential groove 41' has a sharper angle θ than the circumferential groove 41 of the device A, and the circumferential surface 31'a of the spinning roll 31' has a shape corresponding to the circumferential groove 41'. In this case, using device B (overview not shown) having the same structure as device A,
In a similar manner, a circumferential groove portion 29' having a sharper angle θ is formed from the circumferential groove portion 29.

The reason why the circumferential groove portion 29' is formed in two steps as described above is because if it is done in one step, there is a risk that wrinkles will occur. Therefore, if there is no risk of wrinkles occurring in even one step depending on the type and wall thickness of the materials constituting the can body 25 and end members 27, there is no problem in completing the molding in one step.

Next, using the seaming device C shown in FIG. 4, the circumferential groove portion 2 is seamed as shown in FIGS.
A double seam portion 56 is formed from 9'. In FIG. 4, 57 is a seaming rotary chuck, and the peripheral surfaces of its lower straight cylindrical portion 57a and tapered portion 57b are the outer peripheral surface lower portion 39'a and tapered portion of the split mold piece 37' shown in FIG. 3b, respectively. It has the same shape and dimensions as the husband of 39'b. Furthermore, the lower straight cylinder part 5
The outer diameter of 7a is determined to be smaller than the minimum inner diameter of the double-sealed portion 56, so that it can be inserted into and taken out from the end member 27 before and after forming the double-sealed portion 56.

The seaming rotary chuck 57 is fixed to the lower end of a vertical shaft 58, which is rotatably supported by a support 59 and rotated via a gear 60 by a drive mechanism (not shown). Note that the support body 59 is provided so as to be rotatable about a vertical axis (not shown), and the vertical shaft 58 is eccentrically supported with respect to the rotation center.

Then, by rotating the support body 59, the fifth
As shown in FIG. 22a and the lower tapered portion 22b, and by further rotating the support body 59 in the reverse direction, the seaming rotary chuck 57 can be brought into close contact with the side wall main portion 22b.
The structure is such that it is possible to move the can body 25 further apart and lower the can body 25 without the end member 27 coming into contact with the seaming rotary chuck 57.

Reference numeral 61 denotes a presser roll having a flat circumferential surface 61a, which is rotatably supported by a support 62, and by moving the support 62, it can approach the lower straight cylindrical portion 57a of the seaming rotary chuck 57. , are configured so that they can be separated, and in the approached state, in cooperation with the lower straight cylindrical portion 57a of the seaming rotary chuck 57, the short cylindrical portion 63 of the double wall portion 28 below the lower tapered portion 54', that is, the end Short cylindrical side wall main portion 22a of edge material 27
Then, the opening end portion 26a of the can body 25 facing the side wall main portion 22a can be pressed.

A seaming roll 65 is rotatably supported by a horizontal shaft 67 on a vertically movable support 66. The seaming roll 65 is attached to the circumferential groove portion 2
It has a pressing circumferential surface 65a having an inclination corresponding to the lower tapered portion 54' of 9', and the pressing circumferential surface 65a is disposed so as to be vertically movable above the circumferential groove portion 29'. Although not shown, the device C further includes a rotary support plate having a structure similar to the rotary support plate 32 shown in FIG.

Double seaming is performed using the above device C as follows. The can body 25 formed with the circumferential groove portion 29' is placed on a rotary support plate (not shown) in a lowered position so that its axis coincides with the can body 25. At that point, the axis of the seaming rotary chuck 57 is located at the can body 2.
5, the presser roll 61 is spaced apart to the left, and the seaming roll is also located above. Next, the rotary support plate is raised to a position where the bottom surface of the seaming rotary chuck 57 and the panel portion 21 of the end member come into contact.

Next, the support body 59 is rotated, and at the same time the presser roll 61 is moved to the right, so that the lower straight cylindrical portion 5 of the seaming rotary chuck 57 is moved as shown in FIG. 5a.
7a and the presser roll 61, the short cylindrical side wall main portion 22a of the end member and the opening end portion 26a opposite thereto are pressed and supported, and the lower tapered portion 22b of the side wall main portion is seamed by a rotary chuck. 57, and rotate the seaming rotary chuck 57 in the direction of the arrow to open the can body 2.
5 and the circumferential groove portion 29'.

As shown in FIGS. 4 and 5b, the seaming roll 65 is immediately lowered and the circumferential groove 29'
The upper tapered part 55' is pressed until the hanging part 24 comes into contact with the outer surface of the lower tapered part 54', and a double-sealed part 56 is formed by spinning. At this time, the presser roll 61 and the seaming roll 65 rotate in the direction of the arrow. The hanging part 24 is a double seaming part 5
6 becomes the cover hook 68, and the upper tapered part 5
The open end portion 26b located at 5' serves as a body hook 69. 70 is the lower end of the double-sealed portion 56, and 71 is the body foot radius. The double seam portion 56 is made of the sealing compound layer 2.
0 (note that the sealing compound layer 20 is not shown in FIG. 4).

According to the present invention, the circumferential groove portion in the double wall portion is formed by spinning, and since the pressing force is applied in the horizontal direction, substantially no axial load is applied to the can body at this time.

In addition, to form a double seam portion from the circumferential groove, the inner surface of the short cylindrical portion of the double wall portion and the lower surface of the lower tapered portion are supported by a rotary chuck, and the outer surface of the short cylindrical portion is held by a press roll. This is done by spinning while pressing using a seaming roll with a pressing peripheral surface having an inclination that corresponds to the lower tapered part, so that virtually no axial load is applied to the can body during this process. It has this effect.

Therefore, even if the can body is made of a material with low axial load resistance due to thin walls or relatively low rigidity, the double-sealed part with excellent airtightness can be used without causing deformation such as buckling. It has the advantage that it can be formed.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of the main part for explaining the conventional double seaming method, in which Fig. 1a shows the state before double seaming, and Fig. 1b shows the preliminary seaming section. Fig. 1c is a drawing showing a state in which a double seam part is formed, and Fig. 2 is a longitudinal section of an example of an apparatus for forming a circumferential groove part in a double wall part. 3A and 3B are longitudinal cross-sectional views of essential parts for explaining the process of forming a circumferential groove using the apparatus shown in FIG. 2, and FIG.
Figure 3b is a drawing showing the state in which the first step has been completed.
4 is a longitudinal cross-sectional view of an example of a device for forming a double seam portion from a circumferential groove portion, and FIG. 5 is a drawing showing a state in which the second step has been completed, and FIG. FIG. 5A is a vertical cross-sectional view of a main part showing the process of forming a double seam part, and FIG. 5A shows the state immediately before the double seam part is formed, and FIG. It is a drawing. 18...Side wall, 19...Outward curl part, 21...Panel part, 22...Side wall main part, 23...Bending part, 24...
Hanging portion, 25... Can body, 26... Open end, 27...
End member, 28...double wall part, 29, 29'...peripheral groove part, 31...spinning roll, 31a...peripheral surface, 3
1b...Most protruding part, 54, 54'...Lower taper part,
55, 55'... Upper tapered part, 56... Double seaming part, 57... Rotating chuck, 61... Presser roll, 6
3...Short cylindrical part, 65...Seaming roll, 65
a... (pressure) peripheral surface.

Claims (1)

[Claims] 1 A can body having a cylindrical open end is provided with a panel part and a side wall, and the side wall is composed of a bent part and a hanging part connected to the upper end of the main part of the side wall, and the gap width is equal to the thickness of the open end. A method of double-sealing an end member having an outward curl portion approximately equal to the thickness, the open end portion being inserted into the curl portion so that the open end portion and the main portion of the side wall come into contact with each other. The most protruding part of the spinning roll, which rotates around a vertical axis and has a dogleg-shaped peripheral surface convex outward in cross section, hits a part slightly below the hanging part. hand,
a lower tapered portion that presses the double wall portion inward in the radial direction by the spinning roll, bends inward from a position slightly above the panel portion, and extends obliquely upward;
After forming a circumferential groove portion having a dogleg shape in cross section and having an upper tapered portion extending outwardly and obliquely upward, leaving a short cylindrical portion on the double wall portion, by spinning,
The inner surface of the short cylindrical portion of the double wall portion below the lower tapered portion and the lower surface of the lower tapered portion are supported by a rotary chuck, and the outer surface of the short cylindrical portion is pressed by a presser roll. Meanwhile, a seaming roll rotating around a horizontal axis and having a pressing circumferential surface having an inclination corresponding to the lower tapered part presses the upper tapered part until the hanging part contacts the outer surface of the lower tapered part. A double seaming method characterized by forming a double seaming part extending inward and diagonally upward by pressing downward by spinning processing.