JPH0794055B2 - Molding method for can lid with reinforced edges - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for forming a can lid having a reinforced end portion.

[Prior Art] As a method of forming a can lid, for example, as described in JP-A-60-193834 and U.S. Pat. No. 4571978, cut edges arranged on concentric circles, A pair of shearing punches and a drawing die provided on the center side,
Further, a cup-shaped body is formed from the metal blank by using a forming device composed of a pair of drawing punches and a lift ring arranged on the center side thereof and a pair of pads and rings arranged on the center side thereof. A method of manufacturing a can lid by forming a flange portion from the above and then moving the lift ring in the opposite direction to form the countersink portion without restraint is known.

However, this conventional method has a drawback that the formation of the counter sync radius becomes non-uniform.

As a result of various studies on the cause, the present inventors have found that there is a cause that the lift ring is moved in the opposite direction to perform unconstrained molding.

Further, regarding the constrained molding of the counter sink, it is proposed in US Pat.No. 4,716,755,
Even with this method, a good can lid cannot be obtained.

As a result of research on the cause, the following facts were clarified.

The method proposed in the first U.S. Pat. No. 4,716,755 cuts the periphery of a metal blank by a cutting edge, moves a shear punch to a position where a cup-shaped body is formed, and further forms an annular groove. In this case, since the shear punch has to be moved deeper into the die cutter, the movement distance of the shear punch is long, and therefore, the shear punch touches the cut surface of the cut metal blank at a long distance. The so-called metal swarf that is sometimes generated is brought in by the movement of the shearing punch and the movement of the metal blank toward the center, and the phenomenon that the protective layer of the metal blank is damaged or pierced frequently occurs.

The protective layer of the lid has a function of blocking contact between the contents of the can and the metal when it is coated on the can and protecting the metal from corrosion. After filling the product, there is a problem that holes may be formed due to corrosion, and depending on the contents, the generation of hydrogen gas may cause expansion cans and blackening of the contents, and damage to the protective layer must be prevented. That is not the case.

Second, moving the shearing punch deeper from the position where the cup-shaped body is formed requires a long movement distance, which results in a long stroke in the manufacturing process. Is required, the number of products manufactured per unit time is reduced, and a long stroke is required. Therefore, large operating energy is required.

Third, when the die core is fixed and the punch core ring is moved deeply to form the final radius, the movement distance is large, so the stroke in the manufacturing process becomes long, and therefore, it takes a long time to mold the lid. It takes time, the number of products manufactured per unit time decreases, and moreover,
Since it requires a long stroke, it requires a large amount of operating energy.

These are major manufacturing drawbacks.

[Problems to be Solved by the Invention] As a result of various studies, the present inventor has formed a counter-sync radius into a sufficiently rounded and accurate and highly accurate shape, and the movement distance of the punch cutter 2 is set to a necessary minimum length. By shortening it, we succeeded in forming a good peripheral wall,
The problem of bringing in chips and the problem of a longer stroke in the second manufacturing process were solved, and the problem of a longer stroke in the final process was also solved.

MEANS FOR SOLVING THE PROBLEM The present invention is: 1. In the method for strengthening the end portion of a can lid, (a) a die cutter 1 arranged concentrically, and (b) a pair arranged on the center side of the die cutter 1. Eggplant punch cutter 2 and die drawing ring 3, (c) Further, a pair of upper pressure sleeves 4 arranged on the center side of the punch cutter 2 and a die center ring 5 provided with a slope on the center side, and (d) an upper pressure sleeve. 4, a punch center ring 16 disposed adjacent to the center of the punch center ring 4 and (e) a pair of punch centers 6 disposed on the center side of the punch center ring, and a cutting edge into which the tip of the punch center ring 16 is inserted. (A) Punch cutter 2, upper pressure sleeve 4, and punch center 6 are used by using a molding device composed of a die center 7 having a cutout portion 17 in the peripheral portion. The inch center ring 16,
Punch center ring 16 by moving all in the same direction,
The punch center 6 and the upper pressure sleeve 4 are moved to the side of the metal blank 10 provided with a protective layer on the inner side of the can where the protective layer is not provided. (B) Next, the peripheral portion of the cut metal blank 10 is sandwiched by the punch cutter 2 and the die drawing ring 3, and the punch cutter 2 is radiated at the radius base point 8 on the inner peripheral surface of the cutter.
Moves to a position approximately the same as the height of the outer peripheral wall of the flange portion of the can lid to be molded, stops the punch cutter 2 at this position, and moves the wall portion to be the outer peripheral wall 14 of the flange portion of the can lid. Forming the upper pressure sleeve 4
With the die center ring 5, the metal blank 10 is sandwiched and brought into contact with each other, and the punch center ring 16 and the punch center 6 are moved to form the flange portion 15 of the can lid, the chuck wall 11, and the center panel chuck radius 12. (C) Next, by moving the die center 7 and the punch center 6 which are in contact with each other by sandwiching the metal blank in the opposite direction, the notch 17 and the die center ring 5 provided on the peripheral edge of the die center 7 are used. The tip of the punch center ring 16 is inserted into the groove to be formed, and the lower end of the chuck wall 11 is brought into contact with the tip of the punch center ring 16 so that the metal blank is attached to the die center ring 5 and the punch center ring 16.
And a die center 7 to restrain the counter sink radius 13 so as to form the end-reinforced annular groove by restraining the metal blank.

2. In the method of strengthening the end of the can lid, (a) a die cutter 1 arranged concentrically, (b) a pair of punch cutters 2 and a die drawing ring 3 arranged on the center side thereof, c) Further, a pair of upper pressure sleeves 4 arranged on the center side of the die center ring 5 and a die center ring 5 provided with a slope on the center side, and (d) and adjacent to the upper pressure sleeve 4 and the center side thereof. Punch center ring 16 placed in
(E) A pair of punch centers 6 arranged closer to the center than the punch center ring, and a punchin center ring 16
Using a molding device consisting of a die center 7 having a notch 17 into which the tip of is inserted in the peripheral portion, (A) the punch cutter 2, the upper pressure sleeve 4, the punch center 6 and the punch center ring 16,
Punch center ring 16 by moving all in the same direction,
The punch center 6 and the upper pressure sleeve 4 are moved to the side of the metal blank 10 provided with a protective layer on the inner side of the can where the protective layer is not provided. (B) The peripheral portion of the cut metal blank 10 is sandwiched between the punch cutter 2 and the die drawing ring 3, and the punch cutter 2 is moved to form a flanged cup-shaped body. Move the punch cutter 2 at least to a position where it is removed from the punch cutter 2 and the die drawing ring 3 to form a wall portion which becomes the outer peripheral wall 14 of the flange portion of the can lid, and while moving the punch cutter 2 upward from this position, With the upper pressure sleeve 4 and the die center ring 5, the metal blank 10 is sandwiched and brought into contact, and the punch centering is performed. By moving the punch 16 and the punch center 6 to form the flange portion 15 of the can lid, the chuck wall 11 and the center panel chuck radius 12, (C) Next, the die center 7 and the punch that are in contact with the metal blank are sandwiched. By moving the center 6 in the opposite direction, the tip of the punch center ring 16 is inserted into the groove formed by the notch 17 provided in the peripheral edge of the die center 7 and the die center ring 5, and the lower end of the chuck wall 11 is inserted. Part is brought into contact with the front end of the punch center ring 16 to attach the metal blank to the die center ring 5 and the punch center ring 16.
And a die center 7 to restrain the counter sink radius 13 so as to form the end-reinforced annular groove by restraining the metal blank.

3. In the method of strengthening the end of the can lid, (a) a die cutter 1 arranged concentrically, (b) a pair of punch cutters 2 and a die drawing ring 3 arranged on the center side thereof, c) Further, a pair of upper pressure sleeves 4 arranged on the center side of the die center ring 5 and a die center ring 5 provided with a slope on the center side, and (d) and adjacent to the upper pressure sleeve 4 and the center side thereof. Punch center ring 16 placed in
(E) Forming of a pair of punch centers 6 arranged on the center side of the punch center ring, and a die center 7 provided with a notch 17 into which the tip of the punch center ring 16 is inserted in the peripheral portion. Using the device, (A) punch cutter 2, upper pressure sleeve 4, punch center 6, and punch center ring 16,
Punch center ring 16 by moving all in the same direction,
The punch center 6 and the upper pressure sleeve 4 are moved to the side of the metal blank 10 provided with a protective layer on the inner side of the can where the protective layer is not provided. (B) Next, the peripheral portion of the cut metal blank 10 is sandwiched by the punch cutter 2 and the die drawing ring 3, and the punch cutter 2 is moved to form a cup-shaped body with a flange.
Further, the peripheral portion of the flange is at least the punch cutter 2.
The punch cutter 2 is moved to a position where it is disengaged from the die drawing ring 3 to form a wall portion which becomes the outer peripheral wall 14 of the flange portion of the can lid. From this position, the punch cutter 2 is further moved in the same direction while the upper pressure sleeve is being moved. Four
, Die center ring 5 and punch center ring 16
And the punch center 6 are moved to form the flange portion 15 of the can lid, the chuck wall 11 and the center panel chuck radius 12, and (C) Next, the punch center 6 and the die center 7 that is in contact with the metal blank are in contact with each other. By moving the center 6 in the opposite direction, the tip of the punch center ring 16 is inserted into the groove formed by the notch 17 provided in the peripheral edge of the die center 7 and the die center ring 5, and the lower end of the chuck wall 11 is inserted. Part is brought into contact with the front end of the punch center ring 16 to attach the metal blank to the die center ring 5 and the punch center ring 16.
The method for forming a can lid according to claim 1, wherein the end-reinforcing annular groove is formed by constraining a metal blank by constraining it with a die center 7 to form a counter sink radius 13.

4. Move the punch cutter 2, the upper pressure sleeve 4, the punch center 6 and the punch center ring 16 in the same direction so that the punch center ring 16, the punch center 6 and the upper pressure sleeve 4 are located inside the can. The metal blank 10 provided with the protective layer is moved to the side where the protective layer is not provided, and the metal blank 10
4. The punch cutter 2 and the upper pressure sleeve 4 are preceded by the punch center ring 16 and the punch center 6 when the peripheral part of the punch is cut into a circle by the punch cutter 2. A method for forming a can lid, which comprises forming the end-reinforced annular groove according to item 1 by restraining a metal blank.

Is.

[Operation] The first feature of the present invention is to eliminate the unconstrained means in the formation of the counter sink as in the conventional method, and to remove the chuck wall 11 and the center panel chuck radius 12.
When the punch center ring 16 is stopped, the punch center ring 16 is stopped, the punch center 6 and the die center 7 are moved in the opposite directions, and the center side of the metal blank is sandwiched by the punch center ring 16 and the die center 7 to be countered. It forms Syncradius 13.

In this way, by forming the counter sink radius 13 by restraining the metal blank, it is possible to form a counter sink having an accurate shape, so that the fitting with the seaming chuck becomes good when the lid is wound around the can body. The effect of no leakage of the contents is obtained because the thickness of winding is constant without slippage.

The second feature of the present invention is that the radius base point 8 of the inner peripheral surface on the center side of the punch cutter 2 moves to a position substantially the same as the height of the outer peripheral wall of the flange portion of the can lid to be molded, and this position Stop the punch cutter 2 or move the punch cutter 2 until the flange peripheral edge of the flanged cup-shaped body comes off the punch cutter 2 and the die drawing ring 3, and the peripheral edge of the cut metal blank is placed on the center side of the punch cutter 2. By forming a wall portion that becomes the outer peripheral wall 14 of the flange portion while sandwiching it between the inner peripheral surface of the die center ring 5 and the outer peripheral surface of the die center ring 5, the movement distance of the punch cutter is reduced to the minimum distance required for forming the flange outer peripheral wall. Therefore, it was possible to prevent the introduction of cutting chips, eliminate the drawback of damaging the protective layer, and form a good outer peripheral wall of the flange portion.

As described above, according to the present invention, since the stroke of the punch cutter 2 is shortened, the manufacturing speed can be increased and the required energy can be reduced.

Also, while restraining the above-mentioned, Counter Sync Radius 13
Since the punch center 6 and the die center 7 are also moved in the opposite directions when forming, also in this step, the excellent effect that the stroke is short, the manufacturing speed is high, and the required energy is small is obtained.

Further, the third feature of the present invention is to provide these molding devices,
This is to act from the side of the metal blank on which the protective layer is provided on the side that becomes the inner surface of the can without the protective layer.

By carrying out in this way, a burr portion, a so-called burr, generated at the cut end of the metal blank projects only on the side without the protective layer.

Therefore, after forming the lid, it is convenient for stacking and conveying the cans, and as will be described in detail later, in the curling step that is the preforming of winding, the end is curled with the side having the protective layer inside. When the lid molded by the molding method of the present invention, the burr always contacts the curling device,
It is not removed, crushed, or rolled in this step, and does not exist in a so-called burr-like shape.

Therefore, the opening end of the can and the protective layer of the can body are not damaged by burrs when the can is closed, and no corrosion occurs after the can is made.

According to the present invention, the punch cutter 2 is moved to a position where the radius base point 8 of the inner peripheral surface of the center side of the cutter 2 is substantially the same as the height of the outer peripheral wall of the flange portion of the can lid to be molded. It also includes a method of forming a can lid with reinforced end portions by performing all steps while moving in the same direction in the following steps without stopping at. In this case, the effect of the second feature of the present invention is also inferior, but the first and third features
Since it has the feature of (1), it has a far superior effect as compared with the conventional method of manufacturing a can lid.

These effects of the present invention will be described in detail in the next section with reference to comparative examples.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.

In the embodiment, aluminum is used as the metal blank.
A5182P material with a plate thickness of 0.13 to 0.32 was used, and a protective layer of epoxyphenolic resin was provided on the inner surface of the can. The same effect can be obtained by forming the protective layer using a vinyl organosol. A resin coating was also applied to the outer surface of the can for the purpose of lubrication and the like.

1 to 3 are front views in longitudinal section of a part of the molding apparatus used in the present invention. 1 is a die cutter, 2 is a punch cutter, 3 is a die drawing ring, 4 is an upper pressure sleeve, 5 is a die center ring, 6 is a punch center, 7 is a die center having a notch 17 on the outer peripheral surface, and 16 is a punch center. It's a ring.

These devices are arranged concentrically, with the die cutter 1 on the outer peripheral side and the die center 7 on the central side. Each of these devices moves in the direction of the arrow to form the metal blank 10. The metal blank 10 is provided with a protective layer on its inner surface side. Each device contacts the metal blank from the surface side of the metal blank on which the protective layer is not provided to perform the forming process. Each stage of A, B, C, D, E, and F in each drawing shows the progress of the molding process.

Example 1 The apparatus of FIG. 1 is used.

In the stage A, the punch cutter 2 and the die cutter 1 cut the metal blank, and the punch cutter 2 and the die drawing ring 3 sandwich the metal blank and move in the arrow direction.

In the B stage, the punch cutter 2 moves and the metal blank
The ends of 10 are forming a vertical wall, the punch center 6 has not yet hit the metal blank and a cup-shaped lid precursor has been formed. The preceding punch center ring 16 is in contact with the metal blank 10.

In stage C, the radius base point 8 on the inner peripheral surface of the center side of the punch cutter 2 is moved to a position almost the same as the height of the outer peripheral wall of the flange portion of the can lid to be formed, and the punch cutter 2 is stopped at this position. Then, while sandwiching the peripheral edge of the cut metal blank between the inner peripheral surface on the center side of the punch cutter 2 and the outer peripheral surface of the die center ring 5, a wall portion serving as the flange outer peripheral wall 14 is formed, and the punch center 6 is formed. It can be seen that it is in contact with the metal blank.

At the stage D, the upper pressure sleeve 4 is further moved to sandwich the metal blank and contact the die center ring 5 to form the flange 15, and the punch center ring 16
Is shown bending the metal blank 10 downwards.

At the stage E, the punch center 6 moves with the metal blank 10 sandwiched between the die center 7 and the punch center ring 16 moves the metal blank 10 with the die center ring 5 to move the chuck wall 11 and the center panel chuck radius 12. It can be seen that is formed.

In the F stage, the punch center 6 and the die center 7 move in opposite directions with the metal blank 10 sandwiched between them while the upper pressure sleeve 4, the die center ring 5 and the punch center ring 16 sandwiching the metal blank are stopped. It is understood that the counter sync radius 13 is formed with the punch center ring 16 inserted and constrained in the notch 17 formed between the ring 5 and the die center 7.

Example 2 In step C, punch centering was performed as shown in FIG.
The same molding as in Example 1 except that the punch center 16 comes into contact with the metal blank prior to the punch center 6 and the punch center ring 16 is started to be inserted into the cutout portion 17 as shown in FIG. A can lid having a reinforced end portion was formed by the method.

Example 3 The apparatus uses the apparatus shown in FIG.

The steps A, B, D, E, and F are performed in the same manner as in Example 1,
In the step C, the punch cutter 2 is moved to a position where the flange peripheral edge of the flanged cup-shaped body is disengaged from the punch cutter 2 and the die drawing ring 3, and when this position is reached, the punch cutter 2 is moved in the reverse direction, that is, upward. To do.

The position where the peripheral edge of the flange of the flanged cup-shaped body is disengaged from the punch cutter 2 and the die drawing ring 3 is enlarged and shown in FIG. While holding the peripheral edge of the cut metal blank between the inner peripheral surface of the punch cutter 2 on the center side and the outer peripheral surface of the die center ring 5, the flange outer peripheral wall
It can be seen that a wall portion 14 is formed and the punch center 6 is in contact with the metal blank.

In this embodiment, the peripheral portion of the cut metal blank is held between the punch cutter 2 and the die center ring 5 and the punch cutter 2 is moved in the opposite direction, that is, upward to form the flange outer peripheral wall 14, so that the flange portion is When forming, the punch cutter 2 moves in the same direction as the movement of the metal blank drawn toward the center side, and there is no defect that tension is applied to the metal blank, and there is an advantage that performance and thickness of the metal blank are not adversely affected. In addition, the problem of damage to the protective film due to chips does not occur.

Example 4 In step C, the punch center ring 16 contacts the metal blank ahead of the punch center 6 as shown in FIG. 14 and punches in the notch 17 as shown in FIG. 15 in step D. A can lid whose end portion was reinforced was molded by the same molding method as in Example 3 except that the insertion of the center ring 16 was started.

Example 5 The apparatus uses the apparatus shown in FIG. 3, the steps A, B, D, E, and F are performed in the same manner as in Example 3, and the step C is performed on the inner peripheral surface of the punch cutter 2 on the center side. The radius base point 8 is moved to a position almost the same as the height of the outer peripheral wall of the flange portion of the can lid to be formed, and the punch cutter 2 is stopped at this position, or the flange peripheral portion of the flanged cup-shaped body is punch cutter 2. After moving the punch cutter 2 to a position away from the die drawing ring 3 and then moving in the opposite direction without moving in the opposite direction, the entire process is performed while moving in the same direction in the next steps D and E, and the can is reinforced at the end. The lid was molded.

FIG. 16 is an enlarged view of the position where the peripheral edge of the flange of the flanged cup-shaped body is disengaged from the punch cutter 2 and the die draw ring 3 for easy understanding.

This embodiment is different from the above-described first to fourth embodiments in that the punch cutter 2 has a large moving distance, so that a lot of chips are brought in and the stroke in the manufacturing process becomes long. 4 is inferior to Example 4,
Compared with the prior art, for example, the method proposed in US Pat. No. 4,716,755, the moving distance of the punch cutter 2 is smaller by about twice the height of the center panel, and there is no problem in practical use. With the upper presser sleeve 4, the die center ring 5, and the punch center ring 16 sandwiching the punch, the punch center 6 and the die center 7 move in opposite directions with the metal blank 10 sandwiched, and the die center ring 5 and the die center 7 Notch 17 formed between
Since the punch center ring 16 is inserted in and constrained to form the counter sink radius 13, it is possible to form a counter sink with a more accurate shape than the conventional can lid molding method, and the lid is placed on the can body. At the time of winding, the fitting with the seaming chuck is good, slipping does not occur, and the thickness of the winding is constant, so that the contents are not leaked.

Example 6 In step C, punch centering was performed as shown in FIG.
The same as in Example 5, except that the punch center 16 comes into contact with the metal blank prior to the punch center 6 and the punch center ring 16 is inserted into the cutout portion 17 as shown in FIG. A can lid having a reinforced end portion was formed by the method.
Next, in order to specifically explain the effect of the present invention, an example of using the lid obtained by the present invention will be shown.

FIG. 4 is a cross-sectional view showing curling, which is preforming for tightening the lid around the can body. It is understood that the curl forming device 18 has a burr 19 which is a burr 19 protruding outward at the end of the outer peripheral wall of the flange of the lid and is in contact with the curl forming device.

FIG. 5 shows that the burr 19 has disappeared by the curl molding device.

Thus, when the molding device is brought into contact with the metal blank from the side where the protective layer is provided and cut, the burr disappears in the curling process.

FIG. 6 shows the conventional curl molding. As in the present invention, when the metal blank is not subjected to the contact processing of the forming device from a specific direction, the burr 19 does not come into contact with the curl device during the curling and does not contact the curling device.
As shown in the figure, the burr that protrudes inward even after
It turns out that 19 exists.

FIG. 8 shows a cross section of the lid body wound around the can body. It is clearly shown that the burr 19 contacts the can body and damages the protective layer. In addition, if the burr is severe, the hook part of the can body may be cut and the molten metal may leak.

FIG. 9 shows how the lid obtained in the present invention is wound around the can body. Attach the winding device 22 to the outer peripheral wall 14 of the flange portion of the lid.
And the peripheral wall 20 of the opening of the can body is inserted and is now tightened. The seaming chuck 21 is inserted into the countersink of the lid and is fitted precisely to hold the lid in a fixed position during winding. If the counter sync radius does not have a uniform shape with high accuracy, proper fitting with the seaming chuck cannot be obtained, and when the lid is wound around the can body, the seaming chuck and the lid slip and the thickness of the winding tightens. Is not constant and the contents leak. It is understood that the lid body obtained in the present invention has a high precision and a constant shape because the counter blank radius is formed by restraining the metal blank, so that the lid body is properly fitted with the seaming chuck. .

FIG. 10 shows a comparative example, in which a lid having a counter sink radius formed thereon is wound around a can body without restraining a metal blank. It is understood that the accuracy of the counter sync radius is poor and the proper mixing with the seaming chuck is not performed.

[Effect] The present invention provides an accurate and highly accurate counter sync radius by forming a counter sync radius while restraining a metal blank in the molding of the lid,
Accurate winding of the lid and can body, and cutting and molding of the metal blank from the side that is the outer surface of the can prevent damage to the can body protection layer due to burrs and improve product accuracy. Is significantly improved.

[Brief description of drawings]

1 to 3 are embodiments of the present invention and are front sectional views of a part of a molding apparatus used in the present invention, showing each molding apparatus and a molding process at each stage. FIG. 4 is a front sectional view showing a curling step which is a preliminary step of winding around the can body, and FIG. 5 is a front sectional view at the end of the curling step. 6 and 7 are front sectional views showing a conventional curling process, and FIG. 8 is a front sectional view showing a state in which the can body is wound. FIG. 9 is a front sectional view showing a place where the lid body and the can body obtained by the present invention are fastened. FIG. 10 is a front sectional view showing a state where a lid and a can body of a conventional example are wound and tightened. 11 and 12 show another embodiment of the present invention and are front sectional views of a part of the molding apparatus used in the present invention. FIG. 13 is an enlarged front sectional view of a part of the molding apparatus used in the embodiment of FIG. 2 of the present invention. FIGS. 14 and 15 show another embodiment of the present invention and are front sectional views of a part of the molding apparatus used in the present invention. FIG. 16 is an enlarged front sectional view of a part of the molding apparatus used in the embodiment of FIG. 3 of the present invention. FIGS. 17 and 18 are other embodiments of the present invention and are front sectional views of a part of the molding apparatus used in the present invention. 1: Die cutter, 2: Punch cutter, 3: Die drawing ring, 4: Upper pressure sleeve, 5: Die center ring, 6: Punch center, 7: Die center, 8: Punch cutter radius base point, 10: Metal blank, 11: Chuck wall, 12: Center panel chuck radius, 13: Counter sink radius, 14: Flange outer wall, 15: Flange, 16: Punch center ring, 17: Notch, 18: Curling device, 19: Burr, 20 : Peripheral wall of opening of can body, 21: Seaming chuck, 22: Winding device,

Claims (4)

[Claims] 1. A method of reinforced molding the end of a can lid, comprising:
(A) a die cutter 1 arranged concentrically, (b) a pair of punch cutters 2 and a die drawing ring 3 arranged on the center side, and (c) a pair arranged further on the center side. Equipped upper pressure sleeve 4 and die center ring 5 provided with a slope on the center side, (d) punch center ring 16 arranged adjacent to the upper pressure sleeve 4 and on the center side thereof, (e) the punch center ring A punching machine comprising a pair of punch centers 6 arranged closer to the center side and a die center 7 having a notch 17 into which the tip of the punch center ring 16 is inserted is provided at the peripheral edge. 2, upper pressure sleeve 4, punch center 6 and punch center ring 16,
Punch center ring 16 by moving all in the same direction,
The punch center 6 and the upper pressure sleeve 4 are moved to the side of the metal blank 10 provided with a protective layer on the inner side of the can where the protective layer is not provided. (B) Next, the peripheral portion of the cut metal blank 10 is sandwiched by the punch cutter 2 and the die drawing ring 3, and the punch cutter 2 is radiated at the radius base point 8 on the inner peripheral surface of the cutter.
Moves to a position approximately the same as the height of the outer peripheral wall of the flange portion of the can lid to be molded, stops the punch cutter 2 at this position, and moves the wall portion to be the outer peripheral wall 14 of the flange portion of the can lid. Forming the upper pressure sleeve 4
With the die center ring 5, the metal blank 10 is sandwiched and brought into contact with each other, and the punch center ring 16 and the punch center 6 are moved to form the flange portion 15 of the can lid, the chuck wall 11, and the center panel chuck radius 12. (C) Next, by moving the die center 7 and the punch center 6 which are in contact with each other by sandwiching the metal blank in the opposite direction, the notch 17 and the die center ring 5 provided on the peripheral edge of the die center 7 are used. The tip of the punch center ring 16 is inserted into the groove to be formed, and the lower end of the chuck wall 11 is brought into contact with the tip of the punch center ring 16 so that the metal blank is attached to the die center ring 5 and the punch center ring 16.
And a die center 7 to restrain the counter sink radius 13 so as to form the end-reinforced annular groove by restraining the metal blank. 2. A method for strengthening the end of a can lid, comprising:
(A) a die cutter 1 arranged concentrically, (b) a pair of punch cutters 2 and a die drawing ring 3 arranged on the center side, and (c) a pair arranged further on the center side. The upper pressure sleeve 4 and the die center ring 5 provided with a slope on the center side, and (d) and the punch center ring 16 disposed adjacent to and on the center side of the upper pressure sleeve 4.
(E) Forming of a pair of punch centers 6 arranged on the center side of the punch center ring, and a die center 7 provided with a notch 17 into which the tip of the punch center ring 16 is inserted in the peripheral portion. Using the device, (A) punch cutter 2, upper pressure sleeve 4, punch center 6, and punch center ring 16,
Punch center ring 16 by moving all in the same direction,
The punch center 6 and the upper pressure sleeve 4 are moved to the side of the metal blank 10 provided with a protective layer on the inner side of the can where the protective layer is not provided. (B) The peripheral portion of the cut metal blank 10 is sandwiched between the punch cutter 2 and the die drawing ring 3, and the punch cutter 2 is moved to form a flanged cup-shaped body. Move the punch cutter 2 at least to a position where it is removed from the punch cutter 2 and the die drawing ring 3 to form a wall portion which becomes the outer peripheral wall 14 of the flange portion of the can lid, and while moving the punch cutter 2 upward from this position, With the upper pressure sleeve 4 and the die center ring 5, the metal blank 10 is sandwiched and brought into contact, and the punch centering is performed. The punch 16 and the punch center 6 are moved to form the flange portion 15 of the can lid, the chuck wall 11, and the center panel chuck radius 12. (C) Next, the die center 7 and the punch that are in contact with the metal blank are sandwiched. By moving the center 6 in the opposite direction, the tip of the punch center ring 16 is inserted into the groove formed by the notch 17 provided in the peripheral edge of the die center 7 and the die center ring 5, and the lower end of the chuck wall 11 is inserted. Part is brought into contact with the front end of the punch center ring 16 to attach the metal blank to the die center ring 5 and the punch center ring 16.
And a die center 7 to restrain the counter sink radius 13 so as to form the end-reinforced annular groove by restraining the metal blank. 3. A method for reinforcing the end of a can lid, the method comprising:
(A) a die cutter 1 arranged concentrically, (b) a pair of punch cutters 2 and a die drawing ring 3 arranged on the center side, and (c) a pair arranged further on the center side. The upper pressure sleeve 4 and the die center ring 5 provided with a slope on the center side, and (d) and the punch center ring 16 disposed adjacent to and on the center side of the upper pressure sleeve 4.
(E) Forming of a pair of punch centers 6 arranged on the center side of the punch center ring, and a die center 7 provided with a notch 17 into which the tip of the punch center ring 16 is inserted in the peripheral portion. Using the device, (A) punch cutter 2, upper pressure sleeve 4, punch center 6, and punch center ring 16,
Punch center ring 16 by moving all in the same direction,
The punch center 6 and the upper pressure sleeve 4 are moved to the side of the metal blank 10 provided with a protective layer on the inner side of the can where the protective layer is not provided. (B) Next, the peripheral portion of the cut metal blank 10 is sandwiched by the punch cutter 2 and the die drawing ring 3, and the punch cutter 2 is moved to form a cup-shaped body with a flange.
Further, the peripheral portion of the flange is at least the punch cutter 2.
The punch cutter 2 is moved to a position where it is disengaged from the die drawing ring 3 to form a wall portion which becomes the outer peripheral wall 14 of the flange portion of the can lid. From this position, the punch cutter 2 is further moved in the same direction while the upper pressure sleeve is being moved. Four
, Die center ring 5 and punch center ring 16
And the punch center 6 are moved to form the flange portion 15 of the can lid, the chuck wall 11 and the center panel chuck radius 12, and (C) Next, the die center 7 and punch which sandwich the metal blank and are in contact with each other. By moving the center 6 in the opposite direction, the tip of the punch center ring 16 is inserted into the groove formed by the notch 17 provided in the peripheral edge of the die center 7 and the die center ring 5, and the lower end of the chuck wall 11 is inserted. Part is brought into contact with the front end of the punch center ring 16 to attach the metal blank to the die center ring 5 and the punch center ring 16.
The method for forming a can lid according to claim 1, wherein the end-reinforcing annular groove is formed by constraining a metal blank by constraining it with a die center 7 to form a counter sink radius 13. 4. A punch cutter 2, an upper pressure sleeve 4, a punch center 6, and a punch center ring.
A metal blank in which 16 are all moved in the same direction, and the punch center ring 16, the punch center 6, and the upper pressure sleeve 4 are provided with a protective layer on the inner side of the can.
When the peripheral portion of the metal blank 10 is cut into a circle by the punch cutter 2 by moving the punch cutter 2 and the upper pressure sleeve 4 to the side where the protective layer 10 is not provided, the punch center ring 16 and the punch center ring 16 are provided. 6. A method of forming a can lid, wherein the end reinforced annular groove according to any one of claims 1 to 3 is formed by constraining a metal blank.