US3303959A

US3303959A - Can top

Info

Publication number: US3303959A
Application number: US408239A
Authority: US
Inventors: Omar L Brown
Original assignee: Dayton Reliable Tool and Manufacturing Co
Current assignee: Dayton Reliable Tool and Manufacturing Co
Priority date: 1964-11-02
Filing date: 1964-11-02
Publication date: 1967-02-14
Anticipated expiration: 1984-02-14
Also published as: NL149758B; NL6514168A; DK123011B; DE1486353A1; GB1086989A

Description

Feb. 14, 1967 o, BROWN 3,303,959

CAN TOP Filed Nov. 2, 1964 4 Sheets-Sheet 1 Omar Z. E va 7 zzevmzw'g O. L. BROWN Feb. 14, 1967 CAN TOP 4 Sheets-Sheet 2 Filed NOV. 2, 1964 Feb. 14, 1967 o. L. BROWN 3,303,959

CAN TOP Filed Nov. 2, 1964 4 Sheets-Sheet 3 IA/I/EA/TUL Omar Z. 5/440 Feb. 14, 1967 o. BROWN 3,303,959

CAN TOP Filed Nov. 3, 1964 4 Sheets-Sheet 4 United States Patent 3,303,959 CAN TOP Omar L. Brown, Dayton, Ohio, assignor to Dayton Reliable Tool and Mfg. Co., Dayton, Ohio, a corporation of Ohio Filed Nov. 2, 1964, Ser. No. 408,239 24 Claims. (Cl. 220-54) This invention relates to a container having a portion of its wall weakened to serve as a tear strip and having a tab attached to the tear strip to serve as a lever for initiating the severing operation.

In general, the invention is directed to two problems which have come to the fore with widespread acceptance of this type of container. One problem is to make it easier to manipulate the tab for leverage action to initiate the severance of the tear strip. The second problem arises in the use of a container for carbonated beverages and is the hazardous effect of the internal fluid pressure on the tear strip. When the severance of the leading end of the tear strip is initiated by manipulation of the lever, the internal fluid pressure is directed against the underside of the tab while the tab is at a low angle and consequently the pressure against the tab may abruptly complete the severance of the whole tear strip and propel the separated tab away from the container at a dangerously high velocity.

With reference to the first problem of making it easy to lift the tab, it is essential that the tab lie flat until the time arrives to open the container and especially so if the tab is in the top wall of a can. Protruding tabs in tops of the can would create a problem in the fabrication of the cans by high speed machinery and the protruding tabs would also interfere with stacking the cans for storage and shipment.

A conflicting consideration, however, is that if the tab does lie flat against the container wall, it is awkward and diflicult to carry out the lever action for severance of the tear strip because there is insuflicient room for the user to insert his thumb or finger under the free end of the tab. In fact the usual tab lies at such a low angle that the finger force exerted against the end of the tab is largely endwise force with only a small fraction of the applied force converted into a lifting component.

The present invention solves both of these two problems by so constructing and mounting the tab that the actual work performed by the lever action, i.e. the actual severance of the tear strip, is delayed until the tab swings away from the container Wall to an angle great enough for the operator to insert his thumb under the tab sufficiently to grip the tab effectively. At this relatively high angle of the tab, even a force supplied to the end of the tab parallel to the can top has a relatively large lifting component and, of course, thumb pressure applied directly to the underside of the tab is wholly a lifting force.

The invention teaches further facilitating access to the underside of the tab by bending the handle end of the tab slightly outward and by forming an indentation in the container wall adjacent the handle end of the tab. With these further features it is easy to lift the tab to the starting angle and especially so because initially no work load is imposed on the lever. With further reference to the second problem, the invention further teaches the deformation of the leading end of the tear strip by the lever action in such manner that the initially severed metal is positioned to serve as a baffle for directing the high velocity gaseous fluid away from the tilted path.

Given the concept of delaying the severance operation through an initial range of the outward swing of the tab and the further concept of initially deforming the tear strip in a manner to divert the high velocity fluid away from the tab, the problem is presented of constructing the tab and the tear strip in the manner to carry out the two concepts. A new approach is required because in the prevailing types of such containers immediate initiation instead of delayed initiation of the metal severing operation is inherent in the construction of the tab and full impact of the escaping high velocity fluid against the underside of the tab is inherent in the manner in which the tab initially deforms the severed metal.

The invention solves this problem by a novel tab construction which results inherently in delayed resistance to lifting of the tab.

In the usual construction, the whole tab is rigid including the portion of the tab that is connected to the tear strip. For example, in a widely used can construction, the tab is apertured for engagement by a hollow rivet that is formed in the tear strip and the hollow rivet, in effect, becomes a rigid part of the tab. In the new construction, a minor end portion of the tab is connected to the hollow rivet of the tear strip and the remaining major portion of the tab functions as a second-class lever adapted for cam action against the can top. The tab is in effect hingedly connected to the rivet because the tab is flexible to yield and bend freely at the juncture of the two portions of the tab, and the yielding and bending action occurs during an initial portion of the upward swing of the lever before the upward swing encounters the resistance of the actual severance of the tear strip.

In carrying out this concept, the fulcrum end of the second-class lever is made relatively short and is of forked configuration to straddle the rivet. Fortuitously, hingedly connecting the second-class lever to the leading end of the tab together with shortening the fulcrum end of the second-class lever results in initially lifting the leading end of the tear strip to only a slight angle thereby to cause the leading end of the tear strip to serve as a baffle for deflecting the high velocity gases away from the upturned tab.

The second-class lever may be spaced appreciably outward from the can top but such spacing is not necessary for obtaining the delayed action. In the preferred practice of the invention, the aperture of the tab that receives the hollow rivet is formed with a flange or hub portion which may either be turned inward towards the can top or may be turned outward away from the can top. This flange or hub portion which serves as -a collar that tightly embraces the rivet also strengthens the connection between the lever and the rivet and additionally gives high rigidity to the rivet and the adjacent portions of the tab and tear strip that surround the rivet.

Preferably another provision is to round to a radius the forked fulcrum end of the lever that acts against the can top. The rounding of the fulcrum end delays the contact of the fulcrum end with the can top and provides a cam action to lift the rivet for initiating the severance of the tear strip.

These provisions of freeing the lever portion of the tab for swinging movement independent of the rivet, of forming the lever with a relatively short fulcrum end that straddles the rivet, and of rounding the forked fulcrum end of the lever, make it possible to swing the lever outward to a liberal angle before the cam action for severing the metal is started. In addition, the provisions result in initial deformation of the severed metal to a configuration that diverts the escaping fluids from the tab. The liberal angle to which the tab is swung before the severed action is started enables the user to grip the tab effectively for the severing operation and the more effective grip on the tab further reduces the possibility of the tab being projected to the air.

A certain safety feature is provided in that if the lever is swung through the maximum angle of approxi- 3 mately 180 only the leading end of the tear strip is severed and thus there is no tendency for the follow through of the leverage operation to remove the whole tear strip. A further safety feature is the narrowing of the tear strip adjacent its leading end to reduce the magnitude of the force on the tear strip exerted by the internal fluid pressure immediately after the lever action, the force being reduced to such degree that there is no significant tendency for the fluid pressure alone to complete the tearing operation.

The features and advantages of the invention will be understood from the following detailed description and the accompanying drawings.

In the drawings which are to be regarded as merely illustrative FIG. 1 is a fragmentary plan view of a metal can top incorporating the presently preferred embodiment of the invention;

FIG. 1a is a cross section of the tab taken along line 1a1a of FIG. 1

FIG. 2 is a greatly enlarged fragment of FIG.1;

FIG. 3 is a sectional view showing the lever ,at its normal position prior to the operation of opening the can;

FIG. 4 is a similar view' showing the lever lifted through an initial range of movement to a relatively high angle before the lever exerts severing force;

the

FIG. 5 is a similar view indicating how upward swing of the lever through a second short range of movement results in straining the structure without actual severing the metal;

FIG. 6 shows how the lever enters into a third range of its swinging movement to sever the leading end of the tear strip and to deform the leading end to a configuration for deflecting the escaping gases away from the tilted tab, and

outward spacing is not essential. In addition the hub rigidly connects the tab to the rivet and strengthens the portion of the tab that surrounds the rivet.

Two arcuate slots or slits 24 in the metal of the tab on opposite sides of the rivet terminating at two corresponding minute apertures 25 permit the pliable metal of the tab to be bent at the juncture of the two portions of the tab along a transverse dotted line 26. Thus the portion of the lever which extends forward beyond the dotted bend line 26 is of forked configuration to provide two fulcrum ends 27 which straddle the rivet, the fulcrum ends of the rivet being free to swing relative to the rivet instead of being fixedly attached to the rivet. In effect the lever 22 is flexibly or hingedly attached to the hollow rivet 18.

The sheet metal of the lever 22 is suitably offset for longitudinal stiffness. In this instance, the two longitudinal sides and the handle end of the lever are stiffened by a peripheral flange which is shown in section in FIG. 1a and which is rolled under to form a bead 28. In addition the lever 22 is offset to form a shoulder which is U-shaped in plan with the opposite ends of the shoulder extending along the two fulcrum ends 27 of the lever adjacent the two slots 24.

It is important to note that the U-shaped shoulder 30 forms a longitudinal trough 32 in the lever 22, as indicated in FIGS. 1 and 1a, and it is the web in the sheet metal at the bottom of the trough that is flexibly or hingedly connected to the hollow rivet 18. Prefer- FIG. 7 is a fragmentary sectional view showing how the can top may be indented under a fulcrumend to reduce resistance to initial lifting of the tab.

In the embodiment of the invention shown in FIG. 1, a sheet metal can top, generally designated 10, which may be made of a suitable material such as aluminum or steel, is of the usual peripherally flanged configuration as required for joining the can top to a cylindri-' cal can body. The can top 10 is scored along a continuous line 12 to form an elongated tear strip 14 and a suitable sheet metal tab, generally designated 15, is attached to the leading end of the tear strip to function as a second-class lever for initiating severance of the tear strip from the can top. In the construction shown, the tear strip 14 is enlarged in area at its trailing end and short ribs 16 are embossed in the can top adjacent the opposite sides of the tear strip to stiffen the can top and thus facilitate the final severance of the tear strip. It is to be noted that the tear strip 14 is reduced in width in the region 17 adjacent its leading end.

Within the scope of the invention the tab 15 may be connected to the tear strip 14 in any suitable manner. In the present embodiment ofthe invention, however, the leading end of the tear strip is formed with a hollow rivet 18 of circular configuration which extends through a corresponding aperture of the tab in overlapping engagement with the rim of the aperture. A minor forward end portion 20 of the tab is engaged by thehollow rivet 18 and is of circular configuration to conform to the circular configuration of the rivet. The remaining major portion 22 of the tab functions as a second-class lever for initiating the severance of the tear strip.

It is to be noted that the aperture in the minor end portion of the tab that is engaged by the rivet is formed with an inwardly extending cylindrical circumferential flange or hub 23, as shown in FIG. 3 that tightly embraces the rivet. The hub 23 materially strengthens the hollow rivet and in addition spaces the lever 22 outward from the can top, but as heretofore stated such ably the bottom of the trough is stiffened by a short embossed rib 33 spaced from the bend line 26. The shoulder 30 forms a step from the bottom of the trough 32 to a relatively wide U-shaped' marginal portion 34 of the lever that extends along the two longitudinal sides of the lever and around the arcuate end of the lever. The hub 23 of the end portion 20 of the tab spaces the bottom of the trough 32 of the lever 22 outward from the can top 10 and the major area of the ,tab represented by the U-shaped margin 34 is additionally spaced outward from the can top for improved access to the underside of the lever.

Access to the underside of the lever is further facilitated 'by slightly bending up the free end of the lever as shown in section in FIG. 3. A still further provision for improving access to the underside of the lever is the formation of a recess, for example a C-shaped recess 35 in the can top that extends or it could be any other practical depression adjacent the free end of the lever, the recess having sloping sides and extending around the major portion of the circumference of the can top. In addition to improving access to the underside of the lever 22, the recess 35 serves the purpose of eliminating any tendency for the metal of the can top to oil-cam. i.e. snap from a convex configuration in one direction to a convex configuration in the opposite direction when the can is in upside down position and is being filled with liquid.

Preferably the under face of the lever 22 is roughened for more effective gripping of the lever by the fingers of the user. For this purpose the metal of the lever may be offset at distributed points to form bosses or hob nails 37 shown in FIG. 3. I

Since the length of the pair of fulcrum ends 27 of the lever 22 as measured from the bend line 26 is relatively short and since there is an appreciable amount of lost motion in the bending and yielding of the pliable web of the lever in the region of the bend line, the lever may be swung upward to a substantial angle'before the two fulcrum ends start to work on themetal of the can top with cam action on opposite sides of the tear strip to initiate the severance of the tear strip. A further feature of the invention is that the rounding of the two fulcrum ends 27 of the lever as indicated at 38 in FIGS. 3 and 4 to provide the cam action also increases this angle and smooths the action of the lever.

The manner in which the invention serves its purpose may be understood from the foregoing description. The only resistance to the lifting of the lever 22 through an initial range to the relatively large angle shown in FIG. 4 is the relatively slight resistance to yielding and bending of the pliable web of the tab along the transverse bend line 26. Merely engaging the handle end of the lever 22 by the tip of a finger or even by a fingernail is sufficient to lift the tab and the required initial finger engagement with the end of the tab is facilitated by the C-shaped recess 35 in the can top and by the fact that the free end of the lever is bent outwardly in addition to being appreciably spaced from the can top.

Once the lever 22 is swung upward through its first range to this working position in FIG. 4 where the cam action begins, there is adequate room for insertion of the thumb 40 of the user under the lever, as shown, to permit the user to grip the lever firmly between the thumb 40 and the forefinger 42.

In the second range of the outward swinging movement of the lever 22, the two fulcrum ends 27 of the lever exert pressure on the can top on opposite sides of the rivet 18 by cam action with progressively increased stressing of the parts involved without actually initiating severance of the tear strip. This second range starts at the position of the lever shown in FIG. 4 and terminates at a higher angle which may be approximately the angle shown in FIG. 5 where the leading end of the tear strip is ready to rupture. During this second range of swinging movement from the position shown in FIG. 4 to approximately the position shown in FIG. 5, the applied energy results in slight indenting of the metal of the contact of the can top by the short fulcrum ends 27 of the lever and results in deformation of the leading end of the tear strip with slight tilting upward of the hollow rivet 18 as indicated in FIG. 5.

The upward tilting of the hollow rivet results in concentrated stress on the tear strip near the score line 12 in the region indicated 44 in FIG. 5, this region being under the previously mentioned bend line 26 about which the lever pivots. The stress developed by the lever is of high magnitude both because of the cam action and because the length of the two fulcrum ends of the lever is several times the length of the handle portion of the lever as measured from the bend line 26. The progressively increasing stressing of the metal in the region 44 reaches a maximum at approximately the angle shown in FIG. 5 and then the metal yields and ruptures with a snap action. It is to be noted that the metal is thinned by coining as shown in the region 44 to favor the tearing action and to increase the axial dimension of the hollow rivet. The snap action from the position of the lever shown in FIG. 5 to the position of the lever shown in FIG. 6 is the third range of swinging movement of the lever.

FIG. 5 shows how the rivet 18 is tilted by the snap action as the metal is initially torn and it is important to note that the rivet 18 which is the leading end of the tear strip is inclined outward at only a small angle in FIG. 6. Thus it is apparent in FIG. 6 that the lever 22 is bent outward to a high angle to favor avoiding impact by the escaping gaseous fluid and that the tilted rivet or leading end of the tear strip serves as a batfie to deflect the escaping gaseous fluid away from the lever. It will be readily appreciated that the hollow rivet 18 and the associated leading end portion of the tab constitute a rigid tiltable structure and the hub 23 is important in contributing to the required rigidity.

It is to be especially noted that even if the lever is swung beyond the position shown in FIG. 6 to the maximum, no additional lifting action is applied -to the tilted rivet. It is also to be noted that if the user follows through the swinging of the tab from the position shown in FIG. 6 the continued motion of the tab is at an angle to the longitudinal axis of the tear strip with little tendency to cause further tearing of the metal. The user then employs the tab as a handle to pull the tear strip free with the pulling force directed longitudinally of the tear strip.

It may be readily appreciated that it is inherent in the construction of the tab for the resistance to lifting of the tab to rise slowly instead of abruptly as the tab is lifted from its starting position. Since a conventional tab is rigidly connected to the hollow rivet, lifting the tab 3 tilts the rivet 3. In the present lever-cam mechanism, the lever may be lifted several times 3 with only slight tilting of the rivet. Another factor is that only slightly lifting a conventional tab creates stress over a large area of the can wall with a resultant high magnitude resistance. In the present arrangement the stress is concentrated at the two fulcrum ends of the lever and because of the small area a high unit stress results in only moderate resistance to lifting of the tab. When it is further considered that the new arrangement provides a high leverage advantage as well as the force-multiplying advantage of a cam it is easy to understand the freedom with which the lifting of the tab can be initiated. A further factor is in the yielding action of the tab in the region of the connection of the lever with the rivet.

FIG. 7 shows how an indentation 46 may be made in the wall of the can below each fulcrum end 27 of the lever to delay the pressure contact of the lever with the can top and thereby reduce further initial resistance to raising of the tab.

My description in specific detail of the selected embodiment of the invention will suggest various changes, substitutions and other departures from my disclosure within the spirit and scope of the appended claims.

I claim:

1. In a container structure having a wall the combination of:

tear line means forming a tear strip in the wall of the container and having a leading end;

a tab having a lever portion and an end portion, said lever portion defining a fulcrum end adjacent said end portion and a handle portion;

means for securing said end portion of said tab to said tear strip with said handle portion extending generally along the container wall and said fulcrum end spaced from the container wall; and

said tab being pliable at the juncture of said lever and said end portion to allow a predetermined amount of hinged movement of said fulcrum end and said handle portion toward and away from the container wall, respectively, without substantially stressing said tear line means whereby a minimum force can cause said predetermined amount of hinged movement, said fulcrum end being engageable with the container wall and substantially rigidly supported thereby upon said predetermined amount of hinged movement of said handle portion away from the container wall whereby additional hinged movement of said handle portion away from the wall of the container lifts the tear strip to initiate severance thereof.

2. A combination as defined in claim 1 wherein said juncture is intermediate said securing means and the outer extremity of said handle portion whereby said juncture is prevented from moving substantially away from the wall of the container during said predetermined amount of hinged movement and said fulcrum end includes two fulcrum members at least partially straddling said securing means.

3. An improvement as set forth in claim 1 in which said end portion of the tab and the corresponding portion of the tear strip are interconnected to form a rigid structure that is bendable relative to the remainder of the tear strip whereby the rigid structure is tilted outward by the action of the lever portion with the effect of the lever action limited to the severance of the tear strip in the region immediately adjacent to the rigid structure.

4. An improvement as set forth in claim 3 in which the leading end of the tear strip is narrow to minimize the outward force exerted thereon by fluid pressure inside the container thereby to minimize any tendency for the fluid pressure to continue the severance of the tear strip beyond the effect of the lever action.

5. In the construction of a container wherein a wall of the container is weakened to'form a tear strip having a leading end and a tab is connected to the leading end of the tear strip for manual severance of the tear strip, the improvement comprising:

an end portion of the tab being connected to the leading end of the tear strip, the remaining portion of the tab being a second-class lever manually swingable by one end to fulcrum at its other end against the wall of the container to applylifting force to the leading end of the tear strip to initiate severance of the tear strip; the'tab being pliable at the juncture of the two portions for swinging of the lever relative to the end portion, said juncture lying intermediate said one end of said lever and the segment of said end portion of said tab that is connected to the leading end of the tear strip; the lever being longitudinally rigid; and

the end portion of the tab and the corresponding portion of the tear strip being interconnected and forming a rigid structure that is tiltable relative to the remainder of the tear strip whereby the rigid structure is tiltable outward by the action of the lever'with the effect of the lever action limited to the severance of the tear strip in the region immediately adjacent to the rigid structure.

6. In the construction of a container wherein a wall of the container is weakened to form a tear strip and a tab is connected to the tear strip for manual severance of the tear strip, the improvement comprising:

an end portion of the tab being connected to the tear strip, the remaining portion'of the tab being a lever manually swingable by one end to initiate severance of the tear strip;

the tab being pliable at" the juncture of the two portions to yield and bend at the juncture for operation of the lever;

said lever having two fulcrum e portion of the tab; the material of the lever being oifset to stiffen the lever longitudinally; V the material of the tab being cut on opposite sides of the end portion of the tab from said juncture towards the ends of the two fulcrum ends of the lever.

7. An improvement as set forth in claim 6 in which two slits are cut in the material of the end portion of the tab, the two slits extending from said juncture to the ends of the two fulcrum ends respectively; and

in which minute apertures in the tab are provided at the inner ends of the two slits, respectively. 8. In the construction of a container wherein a wall of the container is weakened to form a tear' strip and -a tab is connected to the tear strip for manual severance of the tear strip, the improvement comprising:

an end portion of the tab being connected to the tear strip, the remaining portion of the tab being a lever manually swingable to initiate severance of the tear strip; 7 I

the tab being bendable at the juncture of the two portions for operation of the lever;

the lever being longitudinally rigid and having two fulcrum ends straddling said end portion of the tab; substantially the whole of the lever lying outside the area of the tear strip.

9. In the construction of a container wherein a wall of the container is weakened to form a tear strip and a tab is connected to the tear strip for manual severance of the tear strip, the improvement comprising:

an end portion of the tab being connected to the leading end of the tear strip, the remaining portion of the ds straddling said .end

tab being a lever manually operable to initiate severance of the tear strip;

the lever being longitudinally rigid and having two fulcrum ends straddling said end portion of the tab; and the fulcrum ends of the lever being rounded for cam action against the wall of the container.

10. An improvement as set forth in claim 9 in which the leading end of the tear strip and said end portion of the tab are united to form a rigid structure that is tiltable relative to the remainder of the tear strip and is tilted outward by the action of the lever with consequent severance of the tear strip limited to the leading end of the tear strip.

11. In the structure of a container wherein a wall of the container is weakened to form a tear strip with an outwardly protruding hollow rivet formed in the tear strip and a tab is attached to the hollow rivet for manual severance of the tear strip, the improvement comprising:

an end portion of the tab being connected to the rivet,

the remaining portion of the tab being a second-class lever manually outwardly swingable by one end relative to said end portion of said tab to initiate severance of the tear strip;

the end portion of the tab being formed with an aperture to receive the hollow rivet; and.

the aperture being formed with a flange embracing the rivet to stiffen the rivet and the end portion of the tab.

12. An improvement as set forth in claim 11 which further includes a recess formed in the container wall adjacent the handle end of the lever for better access to the underside of the lever.

13. An improvement as set forth in claim 11 in which the outer end of the lever is bent outward for better access to the underside of the lever.

14. In the construction of a container wherein a wall of the container is weakened to form a tear strip and means is connected to the. leading end of the tear strip to facilitate manual severance of the tear strip, the improvement comprising: 7

a second-class lever hingedly'connected to the leading end of the tear strip, said lever having a handle end, the leading end of the tear strip being offset outwardly to space the lever outward from the container wall; and

the handle end of the lever being offset outwardly from the hinge connection of the lever with the leading end of the tear strip for additional spacing of the handle end outward from the container wall to improve access to the underside of the lever to facilitate manual gripping of the lever.

15. In the construction of a container wherein a wall of the container is weakened to form a tear strip and means is connected to the leading end of the tear strip to facilitate manual severance of the tear strip, the improvement comprising:

a second-class lever hingedly connected to the leading end of the tear strip, the leading end of the tear strip being oifset outwardly to space the lever outwardly from the container wall;

the lever being formed with two fulcrum ends extending forward from the hinge connection and straddling the leading end of the tear strip, said fulcrum ends having rounded surfaces for fulcrum contact with the Wall of the container.

16. In the structure of a container wherein a wall of the container is weakened to form a tear strip with an outwardly protruding hollow rivet formed in the tear strip and a tab has an aperture receiving the hollow rivet with the hollow rivet in overlapping engagement with the rim of the aperture, the improvement comprising:

an end portion of the tab having the aperture that receives the rivet, the end portion being flanged around the rim of the aperture to form 'a collar rigidly embracing the hollow rivet with the collar extending towards the container wall;

the remaining portion of the tab being a second-class lever swingable outward relative to said end portion for severance of the tear strip;

said collar spacing the lever outwardly from the wall of the container to permit the lever to swing to a substantial angle relative to the container wall before the fulcrum ends exert pressure against the container wall for severance of the tear strip.

17. In the construction of a container wherein a metal wall of the container is weakened by a line of scoring to form a tear strip and a tab is connected to the tear strip for manual severance of the tear strip, the improvement comprising:

an end portion of the tab being connected to the tear strip adjacent a portion of the line of scoring, the remaining portion of the tab being a second-class lever manually swingable to initiate severance of the tear strip;

the tab being pliable at the juncture of the two portions;

the lever being longitudinally rigid;

the metal wall of the container in the region of said portion of the line of scoring being coined to facilitate fracture of the metal at said portion of the line of scoring.

18. In the structure of a container wherein a metal wall of the container is weakened by a line of scoring to form a tear strip with an outwardly protruding hollow rivet formed in the tear strip and a tab has an aperture receiving the hollow rivet with the hollow rivet in overlapping engagement with the rim of the aperture, the improvement comprising:

the hollow rivet being adjacent a portion of the line of scoring; the metal can top being coined inwardly in the region of said portion of the line of scoring to increase the axial dimension of the hollow rivet and to facilitate tearing of the metal along said portion of the line of scoring;

an end portion of the tab having the aperture that receives the rivet, the end portion being flanged around the rim of the aperture to form a hub rigidly embracing the hollow rivet; and

the remaining portion of the tab being a second-class lever swingable outward relative to said end portion for severance of the tear strip.

19. In the construction of a container wherein a wall of the container is weakened to form a tear strip and a second-class lever is attached to the tear strip to fulcrum at its end against the container wall, the improvement comprising the forming of an indentation in the container wall in the path of the fulcrum end of the lever to receive the fulcrum end to delay the pressure contact of the fulcrum end against the container wall and thereby reduce resistance to initial swinging movement of the lever.

20. In a container structure, thet combination of:

a container wall;

a tear strip formed in said container wall and manually removable therefrom, said tear strip having a leading end;

a tab having an end portion and a longitudinally rigid second-class lever portion joined by a pliable portion, said second-class lever portion extending outwardly from said end portion and terminating in a handle end; and

connecting means for securing said end portion to the leading end of said tear strip, said pliable portion lying between said connecting means and said handle end, said handle end being manually swingable away from said container wall to cause said second-class lever portion to fulcrum against the container wall to lift the end of the tear strip to initiate severance thereof.

21. In a container structure having a wall, the combination of:

tear line means forming 'a tear strip in the wall of the container;

a tab defining a handle portion adjacent one end thereof and a fulcrum end adjacent the other end thereof;

means for securing said tab adjacent said fulcrum end thereof to said tear strip; and

means for permitting a predetermined amount of hinged movement of said fulcrum end and said handle portion toward and away from the wall of the container, respectively, without substantially'stressing said tear line means whereby a minimum force can cause said predetermined amount of hinged movement, said fulcrum end of said tab being engage-able with the container wall and substantially rigidly supported thereby upon said predetermined amount of hinged movement of said handle portion away from the container wall whereby additional hinged movement of said handle portion of said tab away from the wall of the container lifts the end of the tear strip to initiate severance thereof.

22. In a container structure having a wall, the combination of:

a tab having a lever portion and end portion joined by a pliable portion, said lever portion defining a fulcrum end adjacent said end portion and a handle portion, said pliable portion permitting hinged movement of said lever portion relative to said end portion;

connecting means for securing said end portion of said tab to said tear strip, s'aid pliable portion lying intermediate said connecting means and the outer extremity of said handle portion; and

means for permitting a predetermined amount of hinged movement of said fulcrum end and said handle portion about said pliable portion toward and away from the container wall, respectively, without substantially stressing said tear line means whereby a minimum force can cause said predetermined amount of hinged movement, said fulcrum end being engageable with the wall of the container substantially rigidly supported thereby upon said predetermined amount of hinged movement of said handle portion away from the wall of the container whereby additional hinged movement of said handle portion away from the wall of the container lifts the tear strip to initiate severance thereof.

23. In the construction of a container wherein a wall of the container is weakened to form a tear strip having a leading end and a tab is connected to the leading end of the tear strip for manual severance of the tear strip, the improvement comprising:

an end portion of the tab being connected to the leading end of the tear strip, the remaining portion of the tab being a second-class lever manually swingable by one end to fulcrum at its other end against the wall of the container to apply lifting force to the leading end of the tear strip to initiate severance of the tear strip;

the tab being pliable at the juncture of the two portions for swinging of the lever relative to the end portion;

the lever being longitudinally rigid;

the end portion of the tab and the corresponding portion of the tear strip being interconnected and forming a rigid structure that is tiltable relative to the remainder of the tear strip whereby the rigid structure is tiltable outward by the action of the lever with the effect of the lever action limited to the severance of the tear strip in the region immediately adjacent to the rigid structure;

the continuation of the tear srtip beyond the rigid structure being narrow to minimize the outward force exerted thereon by fluid pressure inside the container to minimize any tendency of the fluid pressure 1 1 1 2 alone to continue the severance of the tear strip be- 1 an end portion of the tab being connected to the hollow yond the effect of the lever action; and rivet, the remaining portion of the tab being a secondthe longitudinal axis of the lever being at a substantial Class level" swillgable y one end t fl at its angle relative to the longitudinal axis of the tear (that end agamst the Wall of the contalnfcl' to pp y lifting force to said end portion of the tab to tilt the hollow rivet to initiate severance of the tear strip;

and l 1 the tab being pliable at the juncture of the two portions for swinging of the lever relative to the end portion.

strip whereby the swinging movement of the lever is 5 directed laterally away from the tear strip to mini mize the tendency of the swinging action to completely sever the tear strip.

24. In the construction of a container wherein a wall of the container is weakened to form a tear strip having Referen'es'cited by the Examiner a leading end and a tab is connected to the leading end of UNITED STATES PATENTS the tear strip for manual severance of the tear strip, the t improvement comprising: 6, 5/1932 Ericsson 220-43 the tear strip being narrowed towards its leading end; 512 1252321 21 an w r ly extending hollow IlVet being formed in 3,225,957 9 Huth V 220 54 the leading end of the tear strip with the hollow rivet extending across the major portion Of the Of E. Primary Exanu-nerthe leading end of the tear strip to stiffen the leading I 7 Y end of the tear strip; G. '1 HALL, Asszstant Exammer.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,303,959 February 14, 1967 Omar L. Brown in the above numbered patthat error appears ent should read as It is hereby certified d that the said Letters Pat ent requiring correction an corrected below.

In the heading to the pr for "assignor to Dayton Reliable To a corporation of Ohio" read assignor, b

to Ermal C. Fraze, Dayton, Ohio inted specification, lines 3 to 5,

01 and Mfg Co Dayton, Ohi

y mesne assignments,

Signed and sealed this 17th day of October 1967.

(SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, Jr. Attesting Officer Commissioner of Patents

Claims

1. IN A CONTAINER STRUCTURE HAVING A WALL THE COMBINATION OF: TEAR LINE MEANS FORMING A TEAR STRIP IN THE WALL OF THE CONTAINER AND HAVING A LEADING END; A TAB HAVING A LEVER PORTION AND AN END PORTION, SAID LEVER PORTION DEFINING A FULCRUM END ADJACENT SAID END PORTION AND A HANDLE PORTION; MEANS FOR SECURING SAID END PORTION OF SAID TAB TO SAID TEAR STRIP WITH SAID HANDLE PORTION EXTENDING GENERALLY ALONG THE CONTAINER WALL AND SAID FULCRUM END SPACED FROM THE CONTAINER WALL; AND SAID TAB BEING PLIABLE AT THE JUNCTURE OF SAID LEVER AND SAID END PORTION TO ALLOW A PREDETERMINED AMOUNT OF HINGED MOVEMENT OF SAID FULCRUM END AND SAID HANDLE PORTION TOWARD AND AWAY FROM THE CONTAINER WALL, RESPECTIVELY, WITHOUT SUBSTANTIALLY STRESSING SAID TEAR