Reclosable lid for a food or beverage container and having a vacuum or pressure release button

A sheet metal lid has a rim portion removably secured and sealed to a container and the lid includes a vent button having a top wall portion surrounded by a side wall portion and an outwardly projecting flange portion. The flange portion of the button has a short arcuate score or shear line extending substantially into the sheet metal, and additional score lines extend into the flange portion at lesser depths to protect a coating on the inner surface of the lid. A resilient sealant material may be bonded to the inner surface of the vent button, and the opposing sheet metal portions of the score line form a small gap for releasing a vacuum or pressure from the container in response to a controlled downward pressure on the top wall portion of the vent button.

BACKGROUND OF THE INVENTION

This invention relates to a closure or lid for a food or beverage container as disclosed, for example, in applicant's U.S. Pat. Nos. 5,979,688, 6,206,220, and 9,701,447 the disclosures of which are herein incorporated by reference. These patents are directed to a thin sheet metal closure or cap or lid for a sealed food or beverage container wherein the closure is removably sealed to the container and reclosable on the container. Commonly, the container is formed of glass but may also be formed plastic or thin sheet metal, and the vacuum or pressure within the sealed container is released to facilitate or simplify the removal of the closure or lid from the container with reduced torque. Other forms of containers with reusable closures for containers and having a vacuum or pressure release structure before the closure is removed from the container are disclosed in U.S. Pat. No. 3,410,436 and U.S. Patent Publication No. US 2014/0103044,

As used herein, the term container includes a glass or sheet metal or plastic container, and the term lid includes any form of removable closure such as a twist-on, twist-off sheet metal cap or a press-on, press-off sheet metal cap or lid for a container. The lid has a peripheral chime or rim portion with a bonded sealant material to form a releasable sealed coupling between the lid and the container.

The lid inner surface may also have a thin plastic coating which protects the contents of the container from exposure to the sheet metal forming the lid. In such an enclosed container and lid assembly, it has been found desirable to add an easily activated and dependable vacuum or pressure release button to the lid, including after the lid has been formed on tooling which shapes the lid and which may have bonded sealant material on the inner surface of the rim portion of the lid. It is also sometimes desirable to minimize the thickness of the sheet metal which forms the lid and to provide some form of visible tamper-proof indication when vacuum or pressure has been released from the container, for example, as disclosed in U.S. Pat. No. 3,152,911.

SUMMARY OF THE INVENTION

The present invention is directed to an improved sheet metal removable lid for a container having a vacuum or pressure enclosed food or beverage product and which includes a vacuum or pressure release button operable with a controlled and dependable pressure to facilitate easy removal of the lid, and to the tooling and method for producing the lid. The method steps of forming the lid are especially adapted for adding the vacuum or pressure release button to a lid which has been pre-formed for removably attaching to a glass jar or sheet metal container. In accordance with one embodiment of the invention, a sheet metal lid having a peripheral rim portion with a bonded sealant material has a center portion formed with tooling in successive stages of a progressive die to form an upwardly projecting vent button within an annular cavity. The button has a top wall portion surrounded by a side wall portion which is surrounded by a flange portion. A main or first score or shear line is formed within the flange portion adjacent the bottom of the side wall portion, and a small portion of the score line is formed to produce a small vent gap in response to a limited pressure on the top wall of the button. The score line extends through at least eighty percent of the thickness of the sheet metal forming the flange portion and may extend completely through the sheet metal. Additional score lines at lesser depths than the main score line may be formed in the flange portion of the button to prevent distortion of the flange portion and the inner plastic coating when forming the button.

An arcuate or annular rib or bead may project downwardly within the flange portion of the vent button and extends adjacent the main score line. The opposing flange portions that define the score or shear line may be pressed axially together or flattened for closing the shear line and controlling the pressure required on the top wall to separate the flange portions and define the small vent gap. A sealant material may be bonded to the inner surface of the vent button below the score line and may have a lip portion which extends to a retention bead. When the top wall of the vacuum release button is pressed downwardly, the opposing flange portions of the button separate and the lip portion of the sealant material extending to the bead peels away from the inner surface of the flange portion of the button and air or gas flows through the gap to release the vacuum or pressure within the container. When the button is released, the sealant recontacts the inner surface of the flange portion of the button due to spring hinge action produced by the sheet metal portions at the opposite ends of the main score line and by the reinforcement provided by the retention rib or bead. These sheet metal portions also limit the small vent gap.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1illustrates a conventional sheet metal removable lid20having a vertical center line21and commonly formed from thin sheet steel having a thickness of about 0.007 or 0.008 inch. The lid20includes a flat circular top wall23surrounded by peripheral horizontal rim portion24with inwardly projecting portions26for releasably engaging or coupling the lid20to an upper portion28of a container30(FIG. 4) in a conventional manner with a twist on, twist off coupling or a press-on and press-off coupling to the container. The inner surface of the rim portion24includes an annular bonded resilient sealant material34(FIG. 3) such as a food grade PVC or plastisol, which forms a tight seal with the container30, in a conventional manner. Either before or after the annular layer of sealant material34is added to the lid20, the lid is formed by progressive die stages to produce a removable lid35(FIG. 2) having a push button vacuum or pressure release vent button40constructed in accordance with the invention.

Referring toFIGS. 3-8, the vent button40is preferably circular and may be located in the center portion of the lid35. The vent button40includes a substantially flat top wall portion44surrounded by a side wall portion46which extends to a surrounding flange wall portion48. The flange wall portion48extends to an outer flange portion52(FIG. 8) connected by an inclined annular wall portion54(FIGS. 7 & 8) to the top wall23of the lid. A downwardly projecting annular rib or bead56projects below the flange wall portion48. As shown inFIG. 7, a semi-circular or arcuate portion of the bead56is spaced outwardly from the side wall portion46of the button40, and as shown inFIGS. 6 and 8, the bead56extends at the bottom of the side wall portion46of the vent button40.

Referring toFIGS. 6 & 7, an arcuate shear line60extends into the flange portion48and is located radially inwardly from the downwardly projecting bead56and adjacent the side wall portion46of the vent button. As shown inFIG. 9, the shear line60may extend completely through the flange portion48of the button40and this is performed by lancing the flange portion between shear die tooling components63and65to separate opposing flange portions48′ and48″. After the shearing or lancing operation ofFIG. 9, the opposing flange portions48′ and48″ are pressed or compressed back together as shown inFIG. 11and into alignment by tooling components67and69to form a tight friction fit between the opposing flange portions48′ and48″.

The optimum desired downward pressure on the vent button40to separate the flange portions48′ and48″ at the shear line60, may also be obtained by pressing a shearing or scoring tool75(FIG. 12) into the flange portion48of the vent button40and against a tooling component or anvil78having a slightly crowned top surface79. The shearing or scoring tool75is pressed into the flange portion48by at least 80% of the sheet metal thickness of flange portion48so that the remaining or residual60′ at the shear line60is approximately 0.0008 inch or less and forms the opposing flange portions48′ and48″. As shown inFIG. 13, the opposing flange portions48′ and48″ are then flattened or pressed back together between opposing flat surfaces of tooling components or members82and83.

Referring toFIG. 14, the residual85at the shear line60of about 0.0008 inch may also be obtained by opposing shearing or scoring members or tools87and88which simultaneously shear or score from both the top surface and the bottom surface of the flange wall48to form the opposing flange portions48′ and48″ and produce the residual85at the shear line60.

Referring toFIGS. 15-17, the downwardly projecting rib or bead56is circular within the flange wall portion48of the vent button40and is concentric with the arcuate shear line60(FIG. 16). As also shown inFIG. 6andFIG. 16, a generally triangular and tapered depression90is formed within the top wall portion44and provides an indication of where the top wall should be pressed above the shear line60to separate the opposing flange portions48′ and48″ as shown inFIGS. 5 and 10. As also shown inFIGS. 5 and 10, a sealant material95such as PVC or plastisol, which may be the same as the resilient sealant material34, is added to the inner surface of the vent button40when the lid is inverted, and the sealant material includes a flange or lip portion97(FIG. 10) which projects radially past the arcuate shear line60and releasably attaches to the retention bead56formed in the flange wall portion48of the vent button40.

Thus, when the top wall portion44of the vent button40is pressed downwardly with a predetermined pressure, the flange portions48′ and48″ separate (FIG. 10) and the flange or lip portion97of the sealant material95peels away from the retention bead56to form a very narrow space or gap100(FIG. 10). The gap permits air above the vent button40to flow into the container28or pressurized gas within the container to flow out of the container and eliminate any vacuum or pressure within the container. Since the sealant material95is in a fluid condition when it is added to the vent button40, and is heated, the sealant material flows under the shear line60and is retained by the bead56under the flange wall portion48of the vent button.

FIG. 18shows another lid110constructed in accordance with a modification of the invention and which is similar to the lid35shown inFIG. 3and which is partially identified with the same reference numbers for similar structure or components but with the addition of a prime mark. In this embodiment, a vacuum or pressure release button120has a top wall portion122, and a surrounding side wall portion124projects downwardly to a surrounding annular flange portion126connected to the top wall portion23′ of the lid by an annular inclined wall portion128. Referring toFIGS. 19 and 20, the flange portion126of the push button120has a main or first score line130and a second score line132which is spaced radially outwardly from the first score line130by a distance D (FIG. 22) of about 0.025 inch. Both of the score lines130and132have a “V” shaped center portion and extend an angle A of about 70 degrees with the main score line130tapering into the metal to the center of the “V”.

As shown inFIG. 22, the score lines130and132are formed by a die135which is pressed into the flange portion126supported by an anvil138having rounded surfaces139below the V-shaped scoring portions142and143of the die135. When the score lines130and132are pressed into the flange portion126against the anvil138, the residual metal thickness R1formed by the main or first scoring die portion142is about 0.001 inch at the center of the “V”, and the residual metal thickness R2formed by the scoring die portion143is about 0.002 inch. As shown inFIG. 20, the main or first score line130is located adjacent the bottom of the side wall124of the button120. The second score line132is located radially outwardly from the first score line130by about 0.025 inch.

Referring toFIGS. 19 and 23, an array or series of ancillary or third score lines148are arcuate and radially within the flange portion126of the button120and are formed by the scoring dies149and an anvil150having a flat surface151to form a metal residual R3within the flange portion126of about 0.0035 inch. Also formed within the top wall122of the button120is a triangular recess155to form an arrow indicating where the top wall122should be pressed in order to rupture the main or first score line130in response to depressing the top wall122of the button.

FIGS. 24-27show a modified form of a button120′ which is identified with some of the same reference numbers as used to describe the push button120, but with the addition of a prime mark. The difference in the button120′ is that the surrounding annular side wall124′ slopes downwardly from the top wall portion122′ to the annular flange portion126′. In all other respects, the score lines130′,132′ and140′ are formed at the same depth as described above for the corresponding score lines inFIGS. 22 and 23. Referring toFIGS. 28 and 29, these show the scoring dies which are the same as disclosed inFIGS. 22 and 23except for forming the first score line130′, the second score line132′ and the third score lines148′ in the flange portion126′ having the sloping side wall portion124′.

FIG. 30illustrates the removable lid110with the push button vacuum release button120attached to a container28and shown slightly concaved as a result of a vacuum within the container28. With a vacuum in the container28, the top wall portion122of the push button120is below the chime or rim24of the lid110. When the top wall portion122of the button120is pushed downwardly, the main or first score line130is slightly ruptured, as shown inFIG. 32to define a small slit or gap100′ to release the vacuum or air within the container. As shown inFIG. 31, when the vacuum is released, the top wall portion122of the button120is still below the chime24of the lid110.

FIGS. 33-35are similar toFIGS. 30-32except that the lid110′ has a push button120′ with a sloping or inclined annular side wall124′ as shown inFIGS. 24-27, with the vacuum release button120′ having the main or first score line130′, the secondary score line132′ and the ancillary or third score lines148′. The primary purpose of the second score lines132and132′ and the third score lines148and148′ are to minimize any distortion or wrinkles within the flange portion126and126′ and thereby protect the thin plastic coating on the inside surface of lid110and110′.

It apparent from the drawings and the above description that a removable container lid provided with a vent button40or120or120′ in accordance with the invention, provides desirable features and advantages. For example, the forming the vent button with the score or shear line60as shown inFIGS. 9 & 11or the shear or score lines as shown inFIGS. 12-14andFIGS. 19-21 and 25-27, provide for obtaining precision and dependable control over the desired pressure on the button to produce a very small gap100or100′ between the opposing flange portions. Also, when the pressure on the top wall portion is released, the spring hinge effect in the sheet metal produced by the annular flange portion on the opposite ends of the score line causes the opposing flange portions to return to their original opposing position or causes the lip portion97of the sealant material to recontact the flange portion48′, thereby closing the gap100to prevent or restrict liquid within the container from flowing through the gap100from the container in the event the container was accidentally tilted onto its side. After the vent gap is open, a light outward or upward pressure on the opposing flange portions defining the gap will also cause the annular flange portion to snap overcenter, thereby closing the gap.

While the reclosable lids and vacuum or pressure release buttons and their method of construction herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to the precise methods and forms of release button described, and that changes may be made therein without departing from the scope of the invention as defined in the appended claims.