JPH0829781B2 - Impact-resistant easy-opening can lid and its manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a can lid for an easy opening container.

Today, various can lids called so-called easy open lids that can easily open the container by attaching a pull tab etc. are used, and a pull open type that pulls up the opening piece forming the opening part and removes it from the lid body Further, there are various easy opening containers such as those that are opened without leaving the connecting portion with the can lid top plate without removing the opening piece from the lid, and further bush open type in which the opening piece is pushed into the container.

The present invention belongs to the pull-open type that causes the tab, but the opening piece is pushed down into the container by the tab tip,
The present invention relates to an easy opening can lid having a bush open type character.

[Conventional technology]

As the can lid of the easy opening container, a type having a pull tab generally called a pull open type is very often used.

However, in the case of the pull-open type, the opening piece forming the opening portion is generally removed from the top plate of the can lid, and the opening piece dissipates, and the end of the opening piece is relatively sharp, so that the limb There is a risk of damaging the device. Therefore, a can lid of a type in which the opening piece has a connecting portion to the top plate so that the opening piece cannot be completely separated from the can lid top plate has been proposed.

In this type of can having a pull-open type connecting portion, when the contents are to be directly drunk from a container such as a container for liquid beverage, an opening piece is located at the tip of the nose, and the break end of the opening piece is relatively sharp. Therefore, there is a drawback that the opening piece at the tip of the nose cannot avoid a sense of incongruity and is not preferred by consumers.

Further, as a can lid of an easy opening container that does not completely separate the opening piece from the top plate, there is a type called a push open type in which the opening piece is pushed into the container.

In this push-open type, there is no danger that the opening piece is located at the tip of the nose, but on the other hand, there is danger because the opening piece is pushed directly with the finger, and in the case where the finger tip etc. is dirty, unsanitary feeling is inevitable There were drawbacks.

For this reason, it is necessary to form a push-open type opening piece and attach a pull tab, and even if it is a pull-open type can lid, give the opening piece a push-open type character and completely remove the opening to the top plate. None, and
The can lid of the easy-open container that does not give a feeling of discomfort or unsanitaryness as described above has been attracting attention.

Conventionally, this type of can lid has been mainly used for internal pressure cans. However, in recent years, it has been strongly required to adopt it for pressure reducing cans as its development in Japan progresses.

A vacuum can easily causes score breakage due to the water hammer phenomenon when dropped. In the can lid used for the decompression can, the top plate is recessed inward due to the pressure difference between the inside and the outside of the can, but when the can is dropped, the liquid in the can jumps up and pushes the can lid at the time of landing. This is the water hammer phenomenon, but at this time, shear stress is applied to the score, the score jumps, and the can lid opens. This tendency was remarkable in the case of the above-mentioned so-called non-separable can lid in which it was necessary to reduce the remaining score thickness in order to minimize the force required for opening the can.

Further, the can lid described in Japanese Utility Model Publication No. 63-23316 is also known. This lid has a continuous deep recess and a shallow recess on the top plate below the tab nose, and when the tip is pressed down, one corner of the tab nose enters the deep recess and does not contact the top plate. The corners go into shallow depressions, which makes it easier to pull tabs. However, at the time of opening by pushing down, one corner of the tab tip hits the bottom of the shallow recess of the recess and pushes down, but since a step with a deep recess is formed in this part, when pushing down,
The shallow depressions are pushed down until they approach the deep depressions and deform, and then act as a pushing force that breaks the score. For this reason, there is a drawback that a part of the pushing-down force is consumed for the deformation of the recess and an extra force is required for the opening. Further, since the power point, the fulcrum, and the point of action are not on a straight line, concentration of the power cannot be performed.

[Problems to be solved by the invention]

As described above, the tab-unseparated can lid, which is a conventional pull-open type and the opening piece has a push-open type, has the drawbacks that it has a weak drop strength and is difficult to open when used for a decompression can. It was

The present invention eliminates such drawbacks, has a sufficient drop strength even with a decompression canister, secures a gap between the canopy top plate of the tab nose portion and the tab, and facilitates the raising of the tab. The pushing force of the opening piece is concentrated on the opening piece so that the opening can be opened with a small force.

[Means for solving the problem]

According to the present invention, "(1) a tab 20 having an arcuate tab nose 21 connected by a rivet 13 and a space 24 that is a hinge between the start point 16 and the end point 17 and is a hinge are provided substantially at the center of the top plate 11. Scored 15 arranged and the opening piece 18 surrounded by the score
In the can lid that is formed by pressing the opening piece down with the tab nose, the water hammer shock absorbing recess 19 having a stepless bottom surface along the score near the rivet is arranged in the area surrounded by the score. A shock-resistant easy-opening can lid in which a buffer band 25 having a narrow width of 0.5 mm to 2.5 mm is arranged between the outer peripheral edge of the recess on the rivet side and the score near the rivet.

(2) The impact-resistant easy-opening can lid according to claim 1, wherein the bottom surface of the water hammer shock absorbing recess 19 is a flat bottom surface having no step.

(3) The impact-resistant easy-opening can lid according to claim 1, wherein the bottom surface of the water hammer shock absorbing recess 19 is a bottom surface of an inclined surface without steps.

(4) The easy opening can lid according to claim 1, wherein the bottom surface of the water hammer shock absorbing depression 19 is a bottom surface of a stepless inverted conical slope formed by a plurality of inclined surfaces.

(5) The impact resistant easy opening can lid according to any one of claims 1 to 4, wherein the water hammer shock absorbing recess is a half-moon shaped recess having an arcuate tip shape.

(6) The score 15 is the score 15 in which the start point 16 and the end point 17 are arranged in front of the rivet and on the same side of either the right or left side of the rivet with a gap 24 serving as a hinge provided therebetween. Impact-resistant easy-opening can lid described in paragraph.

(7) The opening piece 18 surrounded by the score has the irregular beat 14
7. The impact-resistant easy-opening can lid according to claim 1, further comprising:

(8) The impact-resistant easy-opening can lid according to any one of claims 1 to 7, wherein a tab grip portion 22 having an end bent slightly upward is provided at an end of the tab opposite to the tab nose.

(9) On the top plate of the lower surface of the tab grip portion 22, the tab grip recess is formed.
The impact resistant easy opening can lid according to any one of claims 1 to 8, wherein 23 is arranged.

(10) A tab 20 having an arcuate tab nose 21 is connected by a rivet 13 to almost the center of the top plate 11, and a start point 16 and an end point 17 of a score 15 are provided on the side of the rivet with a gap 24 serving as a hinge. , After forming the score by coining in the area surrounded by the score, a water hammer shock absorbing recess 19 having a bottom surface with no step is formed between the outer edge of the recess rivet side and the score near the rivet. Is formed by providing a buffer band 25 having a narrow width of 0.5 mm to 2.5 mm, and a method of manufacturing an impact-resistant easy-opening can lid. Regarding

[Work]

The pull-open type can lid causes the tab near the rivet to cause an initial failure by pulling up the tab when opened. Then, by pulling up the tab, the tab nose pushes down the opening piece downward, and the fracture proceeds along the score.

However, if the opening piece is soft and easily bent when pushed down, or if the pushing down force of the tab does not act intensively, the pushing down cannot be sufficiently exerted and breakage along the score does not occur. In addition, it is necessary to force the tab to be pulled, and it is necessary to hang the finger well.

In particular, in the case of a decompression can, since the top plate is dented inward, the end of the tab is in close contact with the top plate, and there is a strong tendency that fingers cannot be caught. Further, the rectangular tab nose has a disadvantage that the pushing force cannot be concentrated.

The first feature of the present invention is that the water hammer shock absorbing depression prevents the score from being broken due to the water hammer phenomenon when the can is dropped. When the can is dropped, the liquid in the can at the time of landing jumps up in the can and pushes the can lid outward. At this time, a shock called a forter hammer is applied to the can lid. By the way, such a can lid requires pre-processing for attaching tabs, but when baton coining and score processing are performed at this time, a so-called metal remainder is produced in the metal, and especially the score opening piece is remarkably outside. Swell. According to the research by the present inventor, in the case of a decompression can, the can lid top plate is recessed inward due to the pressure difference between the inside and outside of the can, but when the can falls and lands, it is swollen to the outside instantaneously due to the water hammer phenomenon of the content liquid. . In particular, if the can lid top plate has a metal surplus, the bulge becomes large when dropped, so that a larger shear stress is applied to the score, and the score is easily broken.

The problem is that non-separable tub lids tend to have low physical strength because it is necessary to reduce the remaining score thickness in order to minimize the force required for opening the can. When dropped with the lid down, the score is severely broken.

As a result of various studies, the present inventor has found that it is not possible to prevent the opening of the can with a water hammer unless the excess metal phenomenon caused by the arrangement of the scores is solved.

Since the water hammer shock absorbing dent of the present invention absorbs the metal excess generated by the score arrangement, there is no excess metal in the can lid, and the expansion at the time of landing and dropping of the can is reduced, preventing the score from breaking. You can
Moreover, since the water hammer shock absorbing dent on the bottom having no step is arranged along the score on the rivet side where the score is most likely to be broken, breakage of the score can be completely prevented.

As will be clarified in a comparative test to be described later, for example, a recess on the bottom surface having a step like the can lid described in Japanese Utility Model Publication No. 63-23316 described above cannot solve the metal residue phenomenon, and it is opened by a water hammer shock. Will end up.

The fourth feature of the present invention is that the tip of the tab nose is formed in an arc shape. With such a shape, since the opening piece is pushed down by the arcuate tip portion, the force point, the fulcrum, and the point of action can be arranged on a straight line, and the pushing down force is concentrated to perform a strong pushing down action. With a rectangular tab nose, the pressing force is dispersed, and it is not possible to apply sufficient force to the opening piece. Even if only one of the corners is brought into contact with the top plate, one corner of the contacting tab nose rectangle is the point of action but deviates from the line connecting the force point and the fulcrum, and force cannot be concentrated sufficiently due to an unreasonable structure. Further, since the present invention pushes down the bottom surface of the depression at a position away from the start point and the end point of the score, there is no danger of breaking the hinge portion between the start point and the end point. Furthermore, the arc shape increases the rigidity of the tab nose,
It also has the effect of not bending.

The fifth feature of the present invention is that the top plate of the lower surface of the tab nose is
A half-moon shaped water hammer shock absorbing dent is provided so that the bottom surface that receives the tab nose when pulling up the tab knob has a stepless surface.

If the tab nose lowers when pulling up the tab grip portion, it is easy to put a finger on the pulling end, and a sufficient pulling force can be applied. When the crescent-shaped tab nose receiving recess is installed on the top plate, the tab of the tab can be easily pulled up until the tip of the arc-shaped tab nose comes into contact with the bottom of the recess.

The second feature of the present invention is that the bottom surface of the water hammer shock absorbing recess is a stepless surface. According to the research conducted by the present inventor, when a step is provided on the bottom surface of the water hammer shock absorbing dent, the stepped portion has a large distortion, so when the tab nose is pressed down, the stepping force is absorbed and deformed until the step disappears and the step disappears. After that, it was found that it acts as a pushing-down force for score rupture. Therefore, since a part of the applied force is not used for opening the can, a large force is required for opening the can.

Therefore, no step shall be provided on the bottom surface of the water hammer shock absorbing recess.

The bottom surface may be a flat surface or an inclined surface. In the case of a plurality of inclined surfaces, it is preferable that the tab nose tip comes into contact with the lowest part. This area is the most effective as the point of action where the pressing force is concentrated.

A third feature of the present invention is that a buffer band is provided between the stepless bottom dent and the score near the rivet.

As described above, the water hammer shock absorbing depression serves to prevent the score from being broken by the water hammer and to concentrate the pushing down force by the tab nose on the opening force.

According to the study by the present inventor, when the score comes into contact with the depression or is too close to the depression, if not touched, the score is cut by a water hammer. It was found that this kind of score breakage occurs more frequently in the score between the rivet and the water hammer shock absorption recess.

This problem is solved by a buffer zone which is one of the features of the present invention. The buffer zone is arranged between the outer peripheral edge of the depression on the rivet side and the score on the rivet side, and the width is preferably 0.5 mm to 2.5 mm.

 Especially, 1.5 mm to 2.5 mm is optimal.

If it is narrower than this, the score will break during the recess processing. If it is wider than this, the shock absorbing effect cannot be obtained.

A sixth feature of the present invention is that the water hammer shock absorbing recess is provided at a portion of the top plate which is in contact with the opening piece surrounded by the score, so that rigidity is given to the opening piece and the opening piece is deformed and pushed down when it is pushed down by the tab nose. That is, it absorbs the force and prevents the score from breaking.

The seventh feature of the present invention is that the water hammer shock absorbing recess is arranged after the score is arranged.

This is because when the depressions are formed in such an order, the metal surplus generated due to the placement of the score by coining or the like is very effectively absorbed. From the results of the experiment, it was found that absorption of the metal excess was better when the score was formed and then the depression was formed than when the score was formed after the depression was previously formed.

 The can lid of the present invention thus exerts an excellent action.

If the water hammer shock absorbing dent of the present invention is too shallow in order to exert the above-mentioned excellent effects, the open canal effect and the water hammer resistance effect are reduced. On the other hand, if it is too deep, the restraint of the fulcrum will be small and the effect of opening canal will be small. If it is too shallow, the canning effect and water hammer resistance will be less.
The depth of this depression is also related to the length of the tab nose from the rivet. The tab nose length from the rivet is 7-9mm
The effective effect can be seen in the depth range of 0.2 to 1.0 mm.
A depth range of 4 to 0.6 mm is preferred, and the best effect was obtained when the length from the tab nose rivet was 8 mm and the depth was 0.5 mm.

〔Example〕

 Next, the present invention will be specifically described with reference to examples.

FIG. 1 shows the surface of the can lid of the present invention. Reference numeral 10 denotes a can lid, and a top plate recess 12 is provided across the center of the top plate 11. This recess has the effect of providing rigidity, but is not absolutely necessary. A tab 20 is fixed by a rivet 13 to the inside of the recess 12 and substantially at the center of the top plate. The tab nose 21 has an arc shape. A water hammer shock absorbing recess 19 having a half-moon-shaped stepless bottom surface is provided on the top plate on the lower surface of the tab nose. 15 is a score. The scorer is positioned from the front of the rivet around the recess 12 and around the water hammer shock absorbing depression to form an opening piece 18. In addition, in the opening piece, in front of the water hammer shock absorption recess,
A bead 14 is provided to increase the rigidity of the opening piece.

FIG. 2 shows the back of the can lid shown in FIG. It can be seen that the score goes almost once around the opening piece from the front of the rivet. 16 is the starting point of the score and 17 is the ending point of the score. The top plate between the start point and the end point remains uncut at the time of opening, and acts as a hinge 24 connecting the opening piece and the top plate, and functions so that the opening piece does not separate from the lid. Pollution caused by the separated plastic tabs is prevented. The tab knoll is arcuate, and the pushing force concentrates on the tip, so the point where the force is concentrated and the hinge are separated, and the hinge portion is not broken. Numeral 23 denotes a tab knob recess provided on the top plate on the lower surface of the tab knob. If the tip of a finger is inserted into this recess when the tab is raised, the finger is better hooked and the tab can be easily raised.

The buffer zone 25 is arranged between the score 15 near the rivet and the outer peripheral edge of the water hammer shock absorbing recess 19 on the rivet side, and prevents the score hammer from breaking.

FIG. 3 is a sectional view of the can lid of the present invention shown in FIG. 1 taken along the line I-I ', and it is understood that the water hammer shock absorbing recess 19 is formed of a bottom surface having no step. It Since there is no step, the tab nose 21 directly pushes the bottom surface when the opening piece is pushed down, so that all the force is used to push down and open the can. If there is a step, the rigidity of the step is small as described above, and the pushing force is absorbed by the deformation of the step.
Since the force used for opening can be reduced, there is a disadvantage that opening can require much power and time.

In addition, the end portion of the tab grip portion 22 stands slightly upward. Reference numeral 23 denotes a tab knob recess provided on the top plate below the tab knob, and a fingertip can be inserted therein.

As described above, when the tab end portion of the tab is raised and the tab tab depression is provided below the tab end portion, the fingers are satisfactorily hooked when the tab is raised, which is advantageous.

According to the present invention, with such a configuration, the breaking force directly acts on the opening piece by the tab tip, and the score is broken properly. And since an opening piece has a large rigidity and does not bend, it is easy to open a can. Since the tab nose does not hit the hinge part between the start point and the end point of the score, the pushing down force does not act and the break does not occur. Furthermore, the excellent effect that the tab can be easily raised is exhibited.

FIG. 4 is a sectional view of a can lid according to another embodiment of the present invention.
In this embodiment, the bottom surface of the water hammer shock absorbing recess is formed as an inclined surface. Also in this example, there is no step on the bottom surface. When the bottom surface is formed by two or more inclined surfaces, it is most preferable that the tab nose contacts the bottom point formed by these inclined surfaces. Again, there should be no steps.

In order to clarify the effect of the present invention, a conventional can lid is shown and described as a comparative example.

FIGS. 5 to 7 are can lids described in Japanese Utility Model Publication No. 63-23316, and FIGS. 8 to 10 are Japanese Patent Publication No. 57-42545.
The can lids described in the above publications are all conventional can lids shown for comparison.

FIG. 5 shows the front surface of the conventional can described in Japanese Utility Model Publication No. 63-23316, FIG. 6 shows the back surface thereof, and FIG. 7 shows a cross section taken along line II-II 'of FIG.

The tab nose is rectangular, and a recess 19 is provided on the lower top plate at the corner of one tab nose to accept this corner when pushing down and prevent contact with the top plate, and it is shallow next to the recess that receives the corner of the tab nose when pushing down. A recess is provided to prevent the tab grip portion 22 from coming into close contact with the top plate and to facilitate the tab grip portion 22 to be raised. However, since pressing is performed at one corner of the rectangular tab nose, the force point, the fulcrum, and the point of action are not on a straight line, and it is difficult to concentrate the pressing force. Furthermore, in this conventional example, a step is formed between the deep depression and the shallow depression,
Not only can it not absorb the excess metal, but it also has the drawback that it requires a large amount of force and a long time to open because it absorbs the push-down force during opening.

FIG. 8 shows the front surface of the can lid described in Japanese Patent Publication No. 57-42545, and FIG. 9 shows the back surface. FIG. 10 is a sectional view taken along the line III-III 'of FIG.
It is sectional drawing by a line.

In FIG. 8, the tab nose is still rectangular,
Similar to the conventional example shown in FIG. 5, a depression is formed in the top plate below one corner.
19 are provided.

As is clear from FIG. 10, since the other corner of the tab nose is in close contact with the top plate, the tab knob 22 is in close contact with the top plate and it is difficult to raise the tab nose. It can be seen that the point of force, the fulcrum, and the point of action are not on a straight line because the part is depressed, and a sufficient depressing force cannot be exerted structurally.

Further, these canisters have not only a small concentration of the pushing-down force as shown in the comparative test, but also have no protection effect against the water hammer phenomenon due to the small area of the deep depression.

Comparative Test 1 Water Hammer Resistance Can Opening Test In Example 1 of the present invention, the can lid shown in FIGS. 1 to 3 was used. Tab nose recess depth is 0.5mm and inner volume is 350
It is a steel can with a wall thickness of 0.1 mm.
It is a 0.3mm aluminum plate. Also the can lid diameter is 60mm,
The remaining score is 120 μm. The width of the buffer strip is 1.5 mm.

In Comparative Example 1, the can lid shown in FIGS. 5 and 6 was used. The depth of the dent is 0.6 mm and the depth is 0.4 mm, which is a step of 0.2 mm. It is a steel can with an inner volume of 350 ml and a wall thickness of 0.1 mm, and the top plate is an aluminum plate with a thickness of 0.3 mm. The diameter of the can lid is 60 mm, and the remaining score thickness is 120 μm.

In Comparative Example 2, the can lid shown in FIGS. 8 to 9 was used.
The depth of the depression is 0.6 mm, and the thickness of the can wall is 350 mm.
It is a 1mm steel can and the top plate is a 0.3mm thick aluminum plate. Also, the diameter of the can lid is 60 mm, and the score plate thickness is 12
It is 0 μm.

In Comparative Example 3, the same lid was used except that the buffer band of the can lid of Example 1 was removed. The rivet of the water hammer shock absorbing depression 19 on the lid touches the score near the rivet on the outer peripheral edge.

A drop test was performed by filling 100 cans with water. In the test can, the inside of the can was evacuated to 40 cm of mercury. Table 1 shows the test results.
Shown in

<Note> In the test, a single unit was dropped on a wooden board from a height of 100 cm.

All the cans whose scores had run out were counted as crack cans.

Comparative Test 2 Open Can Test The can used in Comparative Test 1 was used in both the examples and comparative examples of the present invention. Each can was filled with water and filled with pure water, and the degree of vacuum in the can was set to 40 cm of mercury.

In the test, the can was fixed and the tab knob was pulled upward, and the force until the score was broken was measured. I also took it on the Kaikan chart at that time.

The results of the comparative test are shown in Table 2, and the open can chart is shown in Figs.
Shown in Figure 13. 11 shows Example 1, FIG. 12 shows Comparative Example 1, and FIG. 13 shows Comparative Example 2.

As is apparent from FIG. 11, in Comparative Example 1 and Comparative Example 2, when the tab grip portion is pulled upward, the opening force is increased at a stroke,
It will be appreciated that a large initial opening force is required.

As described above, the present invention can be opened with a small force, but Comparative Example 1 requires a force until the step is eliminated, and Comparative Examples 2 and 3 have difficulty in causing the tab. Compared to Example 1, 26% of Comparative Example 1, 37% of Comparative Example 2, and Comparative Example 3
Needed a great deal of 16%.

<Evaluation> As is clear from this comparative test, it is understood that the can lid of the present invention can be opened with a small force in a short time and there is no score breakage due to the water hammer phenomenon when the can is dropped. To be done.

[Effects] As described above, the present invention shows excellent opening properties and water hammer resistance, which cannot be achieved by the conventional can lid, because the respective constituent elements are combined with each other, and is extremely easy and safe to handle.

[Brief description of drawings]

FIG. 1 is a plan view of a can lid of the present invention. FIG. 2 is a rear view of the can lid of the present invention, and FIG. 3 is a cross-sectional view taken along line II ′ of FIG. FIG. 4 is a sectional view of a can lid according to another embodiment of the present invention. 5 and 6 are a plan view and a rear view of a conventional can lid, and FIG. 7 is a sectional view taken along the line II-II 'in FIG.
8 and 9 are a plan view and a rear view of another conventional can lid, and FIG. 10 is a sectional view taken along the line III-III 'of FIG. 11 to 13 are charts showing the results of the open canal test. 10; canister 11; top plate 12; top plate recess 13; rivet 14; beads 15; score 16; score start point 17; score end point 18; opening piece 19; water hammer shock absorption recess 20; tab 21; tab nose portion 22 ; Tab tab 23; tab tab recess 24; hinge 25; buffer strip

Claims (10)

[Claims] 1. A tab 20 having an arcuate tab nose 21 connected by a rivet 13 and a start point 16 and an end point 17 are arranged on the side of the rivet and at an interval 24 which serves as a hinge. Score 15 and the opening piece surrounded by the score
In the can lid consisting of 18 and opening the opening piece by pressing down the opening piece with the tab nose, in the area surrounded by the score, a water hammer shock absorbing depression 19 having a bottom surface with no step along the score near the rivet is provided. A shock-resistant easy-opening can lid in which a buffer band 25 having a narrow width of 0.5 mm to 2.5 mm is arranged between the outer peripheral edge of the recess on the rivet side and a score near the rivet. 2. The impact-resistant easy-opening can lid according to claim 1, wherein the bottom surface of the water hammer shock absorbing recess 19 is a flat bottom surface having no step. 3. The impact-resistant easy-opening can lid according to claim 1, wherein the bottom surface of the water hammer shock absorbing recess 19 is a bottom surface of an inclined surface having no step. 4. The easy opening can lid according to claim 1, wherein the bottom surface of the water hammer shock absorbing dent 19 is a bottom surface of a stepless inverted conical slope formed by a plurality of inclined surfaces. 5. A water hammer shock absorbing depression is provided.
A half-moon shaped depression having an arcuate tip shape.
The impact resistant easy opening can lid described in any one of 1 to 4. 6. The score 15 according to any one of claims 1 to 5, wherein the start point 16 and the end point 17 are arranged in front of the rivet and on the same side of either the right or left side of the rivet with a gap 24 serving as a hinge. The impact-resistant easy-opening can lid described in 1 above. 7. The impact-resistant easy-opening can lid according to any one of claims 1 to 6, wherein the concave-convex beat 14 is arranged in the opening piece 18 surrounded by the score. 8. An impact-resistant easy-opening can according to claim 1, wherein a tab grip portion 22 is provided at an end of the tab opposite to the tab nose, and the end is bent slightly upward. lid. 9. The impact resistant easy opening can lid according to any one of claims 1 to 8, wherein a tab knob recess 23 is arranged on a top plate of a lower surface of the tab knob portion 22. 10. A tab 20 having an arcuate tab nose 21 is connected to a substantially central portion of a top plate 11 with a rivet 13, and a start point 16 and an end point 17 of a score 15 are provided on a side of the rivet with an interval 24 serving as a hinge. 19 of the water hammer shock absorption dents that have a bottom of the step-free surface after placing and forming the score by coining in the area surrounded by the score
Is formed by providing a buffer band 25 having a narrow width of 0.5 mm to 2.5 mm between the outer peripheral edge of the recessed rivet side and the score at a position close to the rivet. Manufacturing method.