JP2000190963A - Easy-to-open can-lid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lighten the operation of opening a can lid by means of a tab and ensure the safety of an opened piece, by independently providing gap forming portions, in each of which a fold between the intermediate layer and lowermost layer of an overlapping part is projecting down apart from the lower face of an uppermost layer, in the circumferential, narrow range of the annular overlapping part of a panel. SOLUTION: Gap forming portions 8a, in each of which a fold 2d between an intermediate layer 2b and a lowermost layer 2c is made to project down apart from the lower face of an uppermost layer 2a by forming a gap portion 2e between the uppermost layer 2a and intermediate layer 2b of an annular overlapping part 8, are independently formed in the circumferential, narrow range of the annular overlapping part 8 so as to be situated in the directions of the sides of a tab 4 on the side of a tab leading-end 4a and almost symmetrically with the longitudinal center line Y of the tab 4 between them. Thus, when an annular score line 5 is initially broken, the outermost layer 2a of the annular overlapping part 8 in a portion subjected to a pressing force from the tab leading-end 4a is easily displaced downward. Accordingly, the annular score line 5 can easily and safely be broken with a small force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a full-open type easy-open can lid which is fixedly wound around a can body as an end wall on the top plate side of a can container, and in particular, a portion which is removed when the can lid is opened. In order to prevent the consumer from being injured by the broken end of the opening piece), the panel portion is folded in an annular shape along the edge of the opening piece to be broken and removed, and the panel portion is folded in an S-shape in cross-section to overlap three times. The present invention relates to a full-open type easy-open can lid provided with a safety structure for an opening piece in which a can is formed.

[0002]

2. Description of the Related Art In cans containing contents that require a wide opening, such as canned fruits, canned fish, canned beef, canned vegetables, canned mizuyokan, canned pudding, etc. An opening piece is defined by engraving an annular (endless) score line (notch line) along the periphery of the panel portion of the end wall), and breaking the annular score line to break and remove the opening piece. By fixing the operation tab to the panel so that its tip is close to the annular score line, most of the can lid panel can be opened with the tab operation without the need for a separate can opener. A so-called full-open (easy open) can lid, which is easy to open (easy open), has been conventionally used.

[0003] In such a full-open type easy-open can lid, the panel portion is formed in an S-shaped cross section so as to prevent a consumer from being injured by touching a sharp broken end of a portion (opening piece) removed when the can lid is opened. A multilayer part which is folded three times and is formed in an annular shape (endless along the peripheral part of the panel part) along the edge of a part to be an opening piece of the panel part of the can lid, and the opening piece The structure in which an annular score line is defined in the uppermost layer of the annular multilayer portion is disclosed in, for example, JP-A-48-98899 and JP-A-49-73285.
As disclosed in Japanese Patent Laid-Open Publication No. Sho.

[0004]

By the way, in a full-open type easy-open can lid provided with an annular multilayer portion in order to prevent injuries due to the above-mentioned opening pieces, the opening pieces are broken and removed by operation with a tab. In this case, first, the rear end of the tab fixed near the peripheral portion of the panel portion is lifted (or pulled up) so that the rear end of the tab is a point of force, the fixed portion of the tab is a fulcrum, and the front end of the tab. By applying a pressing force from above to a part of the annular score line engraved around the panel by the tip of the tab, the annular score line is initially set It is broken.

At the time of such initial breakage of the annular score line, a part of the opening piece corresponding to the circularly broken portion of the annular score line is bent downward by the pressing force from above by the tip of the tab. It goes into the can (in this case, the tab is almost perpendicular to the panel part of the can lid),
Thereafter, by pulling the tab upward (or upward and on the side of the rear end of the tab), the portion of the opening piece that has entered the can is pulled upward, and the remaining annular score line is broken, and finally, , The entire score line is broken, and the portion surrounded by the score line is removed as an opening piece.

In a full-open type easy-open can lid from which an opening piece is broken and removed, if the panel portion is triple folded at a portion where the annular score line is engraved, the annular score line is initially broken. At this time, since the portion of the panel portion on which the annular score line is engraved is unlikely to be displaced downward even when receiving the pressing force of the tab, a large force is required to initially break the annular score line.

In this regard, at least in the portion receiving the pressing force of the tab, the uppermost layer engraved with the annular score line is easily displaced downward with respect to the annular multilayer portion along the periphery of the panel portion. The gap forming portion in the state where the intermediate layer and the lowermost bent portion of the portion protrude downward away from the lower surface of the uppermost layer includes a portion receiving a pressing force by the tab (a portion located at the tip of the tab). The formation in the range is described in JP-A-49-73285 and JP-A-49-118589, respectively, and the initial break of the annular score line is considerably caused by such a gap forming portion. It will be easy.

However, after the initial break of the annular score line, in the step of pulling the tab upward (or upward and on the rear end side of the tab) to break the remaining annular score line, the tab is broken and entered into the can. The opening piece portion is hardly deformed even when the tab is lifted upward (or upward and on the rear end side of the tab) because the broken edge portion is triple folded and thickened. When pulling up, the edge of the opening piece that has entered the can comes into contact with the part that was connected before the break (the opening edge of the panel along the flange of the can lid) and receives frictional resistance. Accordingly, a considerable force is required to pull the portion of the opening piece that has entered the can out of the can.

That is, the portion of the opening piece that enters the can along with the initial break of the annular score line is lowered downward at the edges on both sides (near the end points on both sides of the fracture end 51 of the initially broken annular score line). Looking at the degree of bending, if there is no annular layered portion at the edge of the opening piece, as shown in FIG. It is in a state of being sharply bent downward.

On the other hand, when the annular multilayer portion 8 is formed at the edge (portion along the broken end 51) of the opening piece that enters the can, the edge is thick and has high rigidity. As a result, as shown in FIG. 6 (B), the downward bend of the edge portion (the portion along the broken end 51) of the opening piece that enters the can becomes gradual and long, and therefore, it enters the can. When the portion of the opening piece is lifted out of the can, the broken end 51 of the edge of the opening piece comes into contact with the portion that was connected before the rupture was rubbed over the long portion d, resulting in friction. You will receive much resistance.

In the easy opening can lid of the full-opening type, a tab fixed portion (a rivet portion formed integrally with the panel portion for fixing the tab) is fixed to the tab fixed to the panel portion. Are engraved in an arc shape on the center side of the can lid, and an auxiliary score line different from the annular score line is engraved on the panel portion so as to extend both ends thereof in a direction orthogonal to the longitudinal center line of the tab. It is conventionally known that this is the case. (See, for example, Japanese Patent Publication No. 47-31992)

In the easy opening can lid provided with such an auxiliary score line, when the rear end portion of the tab is lifted (or pulled up), first, the front end portion of the tab is near a part of the annular score line defining the opening piece. To apply a pressing force by contacting the tab with the tip of the tab as a fulcrum, the rear end of the tab as a point of force, and the second type of leverage with the tab fixing part as the point of action. The extended auxiliary score line is broken.

The breakage of the auxiliary score line makes it easy to lift the rear end of the tab. When the rear end of the tab is further lifted, the tab fixing portion becomes a fulcrum, the rear end of the tab becomes a force point, and the front end of the tab becomes an action point. The first kind of lever action causes an initial break of an annular score line provided around the panel portion. (The initial break of this annular score line depends on the degree of force applied to lift the rear end of the tab, but even if it breaks in the widest range, it will be a virtual extension line extending in both directions from the arc of the auxiliary score line. It is up to the position where the circular score line intersects.)

Regarding the structure of the auxiliary score line in the easy-opening can lid as described above, the structure of the easy-opening can lid in which the annular layer portion is formed along the edge of the opening piece as described above. Even in an easy opening can lid having an annular layered portion, the provision of the auxiliary score line makes it easy to lift the tab at the time of the initial operation of the opening. The initial break of the score line can be made lighter.

However, the provision of the auxiliary score line, on the other hand, increases the portion of the opening piece that enters the can at the time of the initial breakage of the annular score line, thereby causing the opening piece to break at both side edges at the time of the initial breakage. Since the downward bending is more gentle and longer, when the opening piece that has entered the can is pulled out of the can, the frictional resistance due to the contact of the broken end of the edge of the opening piece as described above is remarkable. As a result, a large force is required to pull up the tab after the initial break of the annular score line, which may give a consumer an impression that it is difficult to open.

An object of the present invention is to solve the above-mentioned problems. More specifically, the present invention relates to a full-open type easy-open can lid provided with a safety structure for an opening piece to be broken and removed. After ensuring the safety of the opening piece to be broken and removed, the portion of the opening piece that entered the can at the time of the initial breakage of the annular score line is pulled out of the can with a small force during the subsequent lifting operation It is an object of the present invention to make it easy to open a can lid in such a manner.

[0017]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a metal can lid in which a flange portion for fixing a can body is integrally formed on an outer periphery of a panel portion.
Along the edge of the part removed at the time of opening the can lid, the panel part is folded into an S-shaped cross section, and an annular multilayer part that is triple overlapped, the side following the can lid center side becomes the lowest layer and the can lid peripheral side A continuous side is formed as the uppermost layer, and an annular score line is engraved on the uppermost layer of the annular multilayer portion. A tab for breaking the annular score line has a tab at the distal end thereof. In an easy-open can lid which is fixed to the panel at the center of the can lid rather than the annular layered portion so as to be close to a part of the line, the center of the tab in the longitudinal direction of the tab is located on the side of the tab on the tip end side of the tab. The gap forming portion in a state where the middle layer of the multilayer portion and the bent portion of the lowermost layer project downward from the lower surface of the uppermost layer at a position substantially symmetrical with respect to the line, in a narrow range in the circumferential direction of the annular multilayer portion. It is characterized by being formed independently of each other.

According to the above-described configuration, the annular score line is initially broken by the operation of the tab, and at the same time, is pressed by the tip of the tab to form one of the opening pieces (the portion removed when the can lid is opened). The part is bent downward and enters the can. At this time, the gap forming part in a narrow range is formed on the side of the tab on the tip end side of the tab with respect to the annular multilayer part along the edge of the opening piece. 6A, the edge of the opening piece is sharply bent downward at the boundary between the gap forming portion 8a of the annular multilayer portion 8 and the other portion, as shown in FIG. The initial break of the annular score line is stopped near the downwardly bent portion of such an opening piece.

Since the edge of the opening piece is sharply bent downward near the portion where the initial break of the annular score line has been stopped (end point of the broken end 51), the opening which has entered the can is obtained. When pulling the piece out of the can,
Compared to the structure shown in FIG. 7B, the broken end 51 of the edge of the opening piece hardly comes into contact with the portion connected before the opening piece was broken, and the frictional resistance due to such contact is almost zero. Since the tab disappears, the tab can be pulled up with a small force after the initial break of the annular score line.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a can lid with easy opening according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a top view of the entire can lid before being wound around the upper end of the can body, and FIG. C-C
3 shows a part of the top surface of the can lid shown in FIG. 1, FIG. 4 shows a part of the cross section of the can lid shown in FIG. 2, and FIG. The cross section along the line AA in FIG.
4 shows a cross section taken along line B.

The can lid 1 is formed by press-molding a thin plate of an aluminum alloy into a body in which a flange portion 3 serving as a portion to be fixed to a can body is integrally formed on the outer periphery of a panel portion 2 serving as an upper end wall of a can container. A separate tab 4 for opening the canned container is integrally fixed to the panel portion 2, and an organic polymer polymer (not shown) is provided on the back side of the flange portion 3. The sealant is applied and adhered.

The panel portion 2 serving as the upper end wall of the canned container includes:
An annular (endless) score line 5 defining an opening piece (a part to be broken and removed when the can lid is opened) is engraved so as to be breakable along the inside of the flange part 3 at a peripheral part of the panel part 2. The tab 4 for breaking the annular score line 5 to remove the opening piece is placed inside the annular score line 5 (can) so that the tip 4a is close to a part of the annular score line 5. At the center of the lid), it is fixed by a rivet portion 21 formed integrally with the panel portion 2.

The portion of the panel portion 2 of the can lid 1 surrounded by the annular score line 5 (the portion to be broken off as an opening piece) is provided with rigidity to the panel portion 2 and a rear end of the tab 4. A concave portion (protruding portion on the back side of the can lid) 22 for facilitating the picking of the portion 4b and providing a printing space for the date of canning and the expiration date, and a tab provided by providing rigidity to the panel portion 2. 4, a convex portion (protruding portion on the surface side of the can lid) 23 in contact with the lower surface of the container 4, a spherical convex portion 24 for keeping the canned upright stability when the cans are stacked, A rib-shaped concave portion 25 for providing rigidity to the panel portion 2 is formed.

An auxiliary score line 6 for facilitating the lifting of the tab 4 in the initial opening operation surrounds the center of the can lid at the center of the can lid of the fixing portion (rivet portion 21) of the tab 4 and has both ends thereof. The tabs 4 are formed so as to extend in a direction perpendicular to the longitudinal center line Y of the tab 4 and to be breakable. In this embodiment, the tab 4
The auxiliary score line 6 (main score line), which is not broken when the tab 4 is pulled up, and the auxiliary score line 6 (main score line) is broken due to the existence of the auxiliary score line 6 (main score line) which is broken when the tab 4 is pulled up. It is formed along the auxiliary score line 6 (main score line) so as to be easily performed.

For such a panel portion 2 of the can lid 1,
To prevent the consumer from being injured by touching the sharp broken end of the opening piece that is broken and removed along the annular score line 5 when the can lid is opened,
A multilayer portion 8 in which the metal plate of the panel portion 2 is folded in an S-shaped cross section and overlapped three times is formed in an annular shape (endless shape) along an edge portion (annular score line 5) of a portion to be an opening piece. .

That is, as shown in FIG. 5 (A), the annular multilayer portion 8 in which the metal plate of the panel portion 2 is folded in an S-shaped cross section and three times overlapped,
The side following the can lid peripheral side (the side of the flange portion 3) is the uppermost layer 2a.
It is formed in an annular shape (endless shape) along the inside of the flange portion 3 around the panel portion 2 so that the side following the can lid center side becomes the lowermost layer 2c. An annular score line 5 is engraved on the upper surface side of the uppermost layer 2a.

With respect to such an annular multilayer portion 8, FIG.
As shown in (B), the uppermost layer 2a of the multilayer portion 8 and the intermediate layer 2
The gap forming portion 8a in a state where the bent portion 2d of the intermediate layer 2b and the lowermost layer 2c is protruded downward away from the lower surface of the uppermost layer 2a by forming the gap 2e between the upper and lower layers 2b and 2b as shown in FIG. A narrow area in the circumferential direction of the annular multilayer portion 8 (preferably in the range of 5 to 10 mm) is located at a position substantially symmetrical with respect to the longitudinal center line Y of the tab 4 on the side of the tab 4 on the side of the tab tip 4a. ) Are formed independently of each other.

That is, in the present embodiment, the gap forming portion 8a of the annular multilayer portion is close to the intersection P between the virtual extension line X extending in both directions from the arc shape of the auxiliary score line 6 and the annular score line 5. In the region on the tip end portion 4a side of the tab 4 with respect to the intersection point P, they are formed independently in a narrow range in the circumferential direction of the annular multilayer portion 8.

Then, each gap forming portion 8 of the annular multilayer portion formed at a position substantially symmetrical with respect to the longitudinal center line Y of the tab 4 apart from the tip end portion 4a of the tab 4 as described above.
A convex portion (a concave portion) 26 serving as a reinforcing rib is formed in the panel portion 2 on the inner side (a can lid center side) with respect to a.

Further, in the present embodiment, apart from the gap forming portions 8a formed substantially symmetrically with respect to the longitudinal center line Y of the tab 4, the gap forming portions shown in FIG. The gap forming portion 8b having the same structure as that of the tab 4a
The portion where the pressing force by the tip 4a of the
Are formed independently of each gap forming portion 8a in a narrow range in the circumferential direction.

Although not shown, the can lid 1 of the present embodiment having the above-described configuration has a can body and a can bottom integrally formed so as to form an upper end wall of a can container. In the case of a canned container, after the content is filled in the main body of the canned container, it is integrally fixed to the upper end of the can body by a flange portion 3 by tightening. The opening operation of the canned container using No. 1 is as follows.

Holding the can with one hand, lift (or pull up) the rear end 4b of the tab 4 with the other hand.
First, the tip 4a of the tab 4 is formed into an annular score line by a second type of leverage action using the tab tip 4a as a fulcrum, the tab rear end 4b as a point of force, and the tab fixing portion (rivet portion 21) as a point of action. 5, a pressing force is applied in contact with the upper surface of the panel portion 2 in the vicinity of the portion, and a lifting force is applied to the tab fixing portion (rivet portion 21).
The auxiliary score line 6 provided around 1) and extending to the left and right thereof is broken.

The breaking of the auxiliary score line 6 facilitates the lifting of the tab rear end 4b, and furthermore, the tab rear end 4b.
When the b is lifted, it is engraved on the peripheral portion of the panel portion 2 by a first type of leverage action having the tab fixing portion (rivet portion 21) as a fulcrum, the tab rear end portion 4b as a force point, and the tab tip portion 4a as an action point. The broken annular score line 5 is initially broken.

The range of initial breakage of the annular score line 5 at this time depends on the degree of force applied to lift the tab rear end 4b. Virtual extension line X extending in both directions
And the vicinity of a position P where the circular score line 5 intersects.

After the initial breakage of the annular score line 5, the tab 4 is lifted (pulled) upward (or upward and on the rear end side of the tab), so that the opening that has entered the can is opened. While pulling the piece out of the can, the remaining annular score line 5 is subsequently broken, and the annular score line 5 is removed.
The opening operation of the canned container is completed by separating the portion surrounded by the canned container from the canned container together with the tab 4 as an opening piece.

In the easily opened can lid of the present embodiment which is opened as described above, when the annular score line 5 is initially broken,
First, at the portion where the pressing force is applied by the tip 4a of the tab 4, a gap forming portion 8b is formed in the annular multilayer portion 8 even though the panel thickness of the portion is increased by the annular multilayer portion 8. The tab tip 4a
Uppermost layer 2 of the annular multilayer portion 8 at the portion receiving the pressing force from
a can be easily displaced downward, and the circular score line 5
In the initial breaking portion where the greatest force is required among the portions that are initially broken, the annular score line 5 engraved on the uppermost layer 2a can be easily broken with a small force. The force required for initial breakage of the annular score line 5 can be reduced.

When the annular score line 5 is initially broken, the annular score line 5 is broken on both sides from the vicinity of the tab tip 4a, and at the same time, an opening piece having the broken annular score line 5 as an edge. Is bent downward by the pressing force of the tab tip 4a and enters the can. At this time, the longitudinal center line Y of the tab 4 is located beside the tab 4 on the tab tip 4a side. As shown in FIG. 6 (A), the gap forming portion 8a is independently and partially formed in the annular multilayer portion 8 at a position substantially symmetrical with respect to the opening piece, and the portion of the opening piece that enters the can is formed as shown in FIG. (The portion along the fractured edge 51) is sharply bent downward at the boundary between the gap forming portion 8a of the annular multilayer portion 8 and the other portion, and the annular score is formed near the bent portion of the edge. The initial break of line 5 will be stopped.

That is, since the gap forming portion 8a has a higher resistance to bending downward (higher rigidity) than the other portions of the annular layer portion 8, the edge of the portion of the opening piece that enters into the can is formed. When a downward bending force acts on (the portion along the fractured edge 51), the downward bending force concentrates at the boundary between the gap forming portion 8a of the annular multilayer portion 8 and the other portions, and this portion is bent. As a result, the edge of the opening piece (the portion along the fractured edge 51) is rapidly bent downward.

In particular, in the present embodiment, a convex portion (or concave portion) 26 serving as a reinforcing rib is formed inside each of the gap forming portions 8a of the annular multilayer portion 8 (on the center side of the can lid). By doing so, such a gap forming portion 8a
Is sharply bent at one edge of the opening, and the position of each gap forming portion 8a is defined by the virtual extension line X extending in the direction extending from the arc shape of the auxiliary score line 6 to both sides.
Is closer to the intersection P of the tangent score line 5 and the annular score line 5 and is closer to the tip 4a of the tab than the intersection P. The stop of the initial break of the annular score line 5 near the bent portion is relatively reliably performed.

Then, the edge of the portion of the opening piece that enters the can as described above (the portion along the broken edge 51) is sharply bent downward at the gap forming portion 8a, and the edge is bent. Since the initial break of the annular score line 5 is stopped in the vicinity of the portion, the portion of the opening piece that has entered the can when the tab 4 is subsequently pulled upward (or upward and on the side of the tab rear end). Can be lifted out of the can with almost no broken end 51 remaining in contact with the broken end remaining on the container body side, so that there is almost no resistance due to contact between the broken end on one side of the opening and the broken end on the container body side. By breaking the score line 5, the opening piece can be removed together with the tab 4 from the container body side.

It should be noted that, for example, Japanese Patent Application Laid-Open No.
In Japanese Patent No. 3285, when an annular score line is initially broken, an annular score line is formed on an annular multilayer portion (annular folded panel) formed along the edge of the opening piece. In order to make it easier for the upper layer to be displaced downward when receiving the pressing force of the tab, the gap forming part that does not completely fold the top cover plate of the annular multilayer part with the intermediate layer is placed on both sides of the tab tip It is described that they are formed over an arc range of 50 degrees (a total of 100 degrees).

In such a structure, at the time of the initial breakage of the annular score line due to the lifting of the tab, the opening piece having the broken annular score line as an edge is bent downward by the pressing force of the tab tip. When entering into the can, at both ends (ie, the boundary between the gap forming portion and other portions) of the range of the arc of 100 degrees where the gap forming portion of the annular layer portion is formed, the portion of the opening piece entering the can is formed. It is also conceivable that the edge is bent down and the initial break of the annular score line is stopped.

However, in such a device, although the gap forming portion of the annular multilayer portion is partially crushed at the portion where the pressing force of the tab tip directly acts, the range of the 100 ° arc excluding such a point is excluded. In most cases, since the gap forming portion exists continuously and long, the risk of injury due to the broken end formed in the uppermost layer is avoided by the bent portion of the intermediate layer and the lowermost layer below, The safety of the opening piece by the annular multilayer portion cannot be sufficiently ensured.

On the other hand, in the present embodiment, the gap forming portion 8b formed at the position of the tab tip 4a is almost crushed by the pressing force of the tab tip 4a when the annular score line 5 is initially broken. The gap forming portions 8a formed at positions substantially symmetric with respect to the longitudinal center line Y of the tab 4 are not crushed when the annular score line 5 is initially broken. Since the gap 8 is formed independently and partially in a narrow range in the circumferential direction of the portion 8, there is a danger of injury due to a broken end formed in the uppermost layer of the annular multilayer portion 8 by the gap forming portion 8 a. This does not occur, and the safety of the opening piece due to the provision of the annular multilayer portion 8 is sufficiently ensured as compared with the structure described in the above cited publication.

Although the embodiment of the can lid of the present invention which can be easily opened has been described above, the present invention is not limited to the specific structure as shown in the above embodiment, but can be appropriately designed. Needless to say, it can be changed.

For example, as for the shape of the can lid, the can lid 1 shown in the drawings as the embodiment is circular, but may be an elliptical shape or a rounded rectangular shape according to the shape of the canned container. The meaning of "annular" in the case of "line" or "annular multilayer part" is not limited to a circular shape, but it means, of course, simply an endless shape along the outer shape of the can lid.

In the above embodiment, the auxiliary score line 6 is formed in order to facilitate the lifting of the tab 4,
In order to facilitate the first breakage of the annular score line 5 by the tab tip 4a, a gap forming portion 8b is formed at the position of the tab tip 4a of the annular layer portion 8, but an auxiliary score line is provided. The present invention can also be applied to an easy-to-open can lid having no opening, and the gap forming portion located at the tip of the tab can be omitted in some cases.

[0049]

According to the easy-open can lid of the present invention as described above, in order to prevent injury due to the broken end of the opening piece to be broken and removed, the can piece is formed along the edge of the opening piece. Despite the annular layer portion being formed on the panel portion, the edge of the opening piece that enters the can is sharply bent downward due to the initial breakage of the annular score line, and in the vicinity of this bent portion By stopping the initial rupture of the annular score line, in the opening operation after the initial rupture of the annular score line, the portion of the opening piece that has entered the can can be out of the can with little force with little frictional resistance. In this way, the opening operation of the can lid by the tab can be performed lightly, and the safety of the opening piece due to the formation of the annular layer portion can be sufficiently ensured.

[Brief description of the drawings]

FIG. 1 is a top view showing an embodiment of an easily openable can lid according to the present invention before being fixed to an upper end of a can body as an upper end wall of a canned container.

FIG. 2 is a cross-sectional view of the can lid shown in FIG. 1 taken along line CC.

FIG. 3 is a top view partially showing the vicinity of a tab of the can lid shown in FIG. 1;

FIG. 4 is a cross-sectional view of the can lid shown in FIG. 3 taken along a center line Y in the tab longitudinal direction.

FIG. 5 is a cross-sectional view taken along line AA of FIG. 1 and FIG. 5B is a cross-sectional view taken along line BB of FIG. 1 with respect to an annular multilayer portion formed on the panel portion of the can lid shown in FIG. Sectional view along the line.

FIG. 6 shows a gap between the edge of the opening piece (the portion along the broken end) which enters into the can with the tip of the tab when the annular score line is initially broken, and (A) a gap between the annular multilayer portion at the edge of the opening. A can lid of the present invention in which a forming portion is provided, (B) a comparative example in which no gap forming portion is provided in the annular multilayer portion at one edge of the opening,
(C) An explanatory side view showing each of the can lids having no annular layer portion at one edge of the opening.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Can lid 2 Panel part 2a Uppermost layer (of annular multilayer part) 2b Middle layer (of annular multilayer part) 2c Bottom layer (of annular multilayer part) 2d Bending part of intermediate layer and lowermost layer (of annular multilayer part) 3 Flange Part 4 Tab 4a Tab tip part 5 Annular score line 6 Auxiliary score line 8 Annular multilayer part 8a Gap forming part 8b (at a position distant from tab tip) Gap forming part (located at tab tip) 26 Reinforcing X The virtual extension line extending in both directions from the arc shape of the auxiliary score line Y The longitudinal center line of the tab P The intersection of the virtual extension line of the auxiliary score line and the circular score line

Claims (4)

[Claims] 1. A panel section is cut along an edge of a portion to be removed when a can lid is opened with respect to a metal can lid in which a flange section for fixing a can body is integrally formed on an outer periphery of the panel section. S
An annular multilayer portion folded in a letter shape and overlapped three times is formed so that the side following the can lid center side is the lowermost layer and the side following the can lid peripheral side is the uppermost layer, and on the uppermost layer of the annular multilayer portion. An annular score line is engraved, and a tab for breaking the annular score line is provided at the center of the can lid with respect to the annular layer portion so that its tip is close to a part of the annular score line. In the easy-open can lid fixed to the part, bend the middle layer and the lowermost layer of the multilayer part at the side of the tab on the tip side of the tab and at a position substantially symmetrical with respect to the longitudinal center line of the tab. An easily openable can lid, wherein gap forming portions in which the portions protrude downward away from the lower surface of the uppermost layer are formed independently in a narrow range in the circumferential direction of the annular multilayer portion. 2. An auxiliary score line for facilitating an opening operation using a tab is formed in an arc shape around the center of the can lid at the center of the can lid, separately from an annular score line serving as an opening cut portion of the can lid. A virtual extension line and a circular score line extending in the direction extending to both sides from the arc shape of the auxiliary score line are engraved on the panel portion so as to extend from the both ends thereof in the direction orthogonal to the longitudinal center line of the tab. The easy-open can lid according to claim 1, wherein the gap forming portion is formed near the intersection of the can. 3. A gap forming portion having a similar structure to a gap forming portion independently formed at a position substantially symmetrical with respect to a longitudinal center line of the tab and corresponding to a tip end portion of the tab. 3. The ring-shaped multilayer portion is formed independently in a narrow area in the circumferential direction at the position. 4.
The easy opening can lid according to 4. 4. A reinforcing projection is provided on a panel portion on the center side of a can lid for a gap forming portion of an annular multilayer portion independently formed at a position substantially symmetrical with respect to a longitudinal center line of a tab. The easy-open can lid according to any one of claims 1 to 3, wherein a portion or a concave portion is formed, respectively.