US 3160302 A
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Description (OCR text may contain errors)
e. F. CHAPLIN 3,160,302
CONTAINER CLOSURE Filed NOV. 3, 1960 nvvmron. 4 GeorgeFCizapan,
United States Patent 3,160,302 CONTAINER CLOSURE George F. Chaplin, Elmwood Park, 111;, assignor to Continental Can Company, Inc., New York, N.Y., a corporation of New York Filed Nov. 3, 1960, Ser. No. 67,192 Claims. (Cl.21538) This invention relates to containers and is more particularly concerned with improvements in a presusre indicating member therefor which is in the form of a flexible panel constructed to assume different positions depending upon the pressure condition within the container.
In the vacuum packaging of certain products such as a number of different foods, the products are placed in cans, jars or similar containers and the necessary caps or equivalent closure members are applied to the same while under vacuum, after which, the closed and sealed containers are placed in a retort or similar apparatus for processing. In thecourse of processing, substantial pressure will build up in the retort which holds the closure members on the containers and imposes a force on the outside of the same which is generally greater than the pressure built up in the container due to the heating of the contents and which is, of course, relieved when the processing is completed and the containers are removed and cooled to a point where vacuum conditions are restored in the container. Proposals have heretofore been made for providing cans or jars for this type of vacuum packaging which would have pressure responsive panels designed to indicate by their position the presence or absence of vacuum conditions in the containers after they have been processed so as to enable leakers to be readily detected and segregated from those in which the vacuum has not been lost through the processing or han dling. However, the pressure or vacuum indicating panels proposed have not proven satisfactory because they were deformed or distorted when subjected to the overriding pressures of the retort or other processing apparatus and subsequently failed to function properly when the containers were restored to their normal condition. It is an object of the present invention, therefore, to provide an improved pressure indicating means for use in the vacuum packaging of food or similar products which is so constructed that it will not be damaged or its proper functioning impaired by the pressure conditions encountered during the processing of the filled package in a retort or similar processing apparatus.
It is a more specific object of the invention to provide a closure member for a sealed container having a portion of the wall thereof which is flexible and which will assume different positions in response to a change in the pressure differential on opposite faces thereof without becoming permanently deformed or distorted to an extent which would prevent it from returning to its initial condition when the pressure on opposite faces is equal.
It is a further object of the invention to provide a pressure indicating portion in a closure cap or other wall forming member of an hermetically sealed container Which normally has a convexo-concaved or dome shape and which can be flexed into a concavo-couvexed position by the application of pressure on the exterior surface thereof, which pressure indicating portion will automatically return to its normal position when the pressure is discontinued.
It is a still further object of the invention to provide a closure cap for application to a jar or similar container which has a flexible panel portion in the shape of a dome with center and peripheral sections of the dome being on different radii, whereby the dome will flex toward one side or the other of the panel in response to changes in p 3,160,302 Patented Dec. 8, 1964 the pressure on the opposite sides of the panel and automatically provide an indication of the pressure conditions within the container.
These and other objects and advantages of the invention will be apparent from a consideration of the closure member which is shown by way of illustration in the accompanying drawings wherein:
FIGURE 1 is a perspective view of the top portion of a container having a closure cap applied thereto which embodies the principal features of the invention;
FIGURE 2 is a cross section of the cap in its initial condition prior to application to a container taken on the line 2-2 of FIGURE 1, to an enlarged scale;
FIGURE 3 is a cross section, to an enlarged scale, taken on the line 22 of FIGURE 1 showing the cap after the same is applied to a vacuumized container; and
FIGURE 4 is a partial cross section taken as in FIG- URE 2, but to a still larger scale.
Referring to the drawings, the invention is illustrated as embodied in a Twist-Off closure member 10 which may be a screw cap or a lug cap as shown in FIGURES 2 to 4, of the type commonly used in conjunction with a resilient gasket material 11 for sealing a glass jar 12 or similar container. The closure member or cap 10 has a top panel 13 and a peripheral skirt 14 with the marginal edge of the skirt curled at 15 and provided with a plurality of spaced lugs '16 for wedging beneath the bottom of a head or thread portion 17 on the exterior edge of the jar 12 adjacent the mouth or top opening thereof. The top panel 13 is shaped to provide a central dome portion 13 which is in the form of two intersecting spherical sections having different radii. The center section or portion 1? of the dome 13 has a diameter D-l as indicated in FIGURE 4 and is formed on a radius R'1 while the remainder or outer section or portion 20 of the dome has a diameter D-2 as indicated in FIGURE 4 and is formed on a radius R-2. In a typical cap formation which has been found to operate successfully, the center portion 19 is one-half inch diameter and is formed on a radius of six inches while the outer portion 20 has a diameter of one inch and is formed on a radius of four inches, the radii R-1 and R-2 both having their centers on a vertical center line which is perpendicular to the top 7 plane of the cap as indicated in FIGURE 4. The dome section 23. The angular relation of section 22 with section 23 which is indicated at a in FIGURE 4 is in the neighborhood of 10 degrees but may vary within limits of;
approximately 4 to 2 degrees relative to the plane of the section 23. The flat section 23 extends to an upwardly tapered section 24 which is relatively narrow and which connects the same with the outermost panel section 25, the latter constituting the margin of the top panel 13 of the cap. and lying in the topmost plane thereof. The outermost tapered portion 24 is at an angle to the topmost plane of the cap which is sufficient to bring the dome portion 18 below the top planeof the cap when the dome portion is flexed upwardly to the limit of its movement as in FIGURE 2 so as not to interfere with stacking.
In the dome portion 18 of the cap, which constitutes the primary flexible portion, the center spherical section 19 has a radius R-l which is in all instances made greater than the radius R-2 of the surrounding spherical section 20 so that there is a slightly greater curvature or convexity in the outer or peripheral portions or area of the dome 13, while the center area is on a somewhat flatter curve.
In use, the cap is adapted to be applied to the top of a glass jar or similar threaded container 11 and rotated or sealed container is removed from the vacuum chamber the dome portion 18 of the top panel of the cap is forced by atmospheric pressure on the outside surface of the cap into the inwardly flexed position shown in FIG- URE 3. Thereafter, when the capped container is placed row, upwardly and outwardly tapered band portion, and an upwardly domed center portion which is connected at its margins to said flat portion by a relatively narrow band portion which tapers inwardly and upwardly of said flat portion, said domed center portion being in the form of intersecting spherical sections on two different radii with the radius of the section at the center being larger than the radius of the section at the perimeter whereby said domed portion will flex downwardly when predetermined vacuum is retained in the container 11. Should a leak occur, or when the cap 10 is twisted to remove the same,
the dome section 18 will spring back to its normal position as shown in FIGURES 2'and 4 with a snapping sound which is clearly audible, thus enabling the change in the internal condition of the container to be observed and also heard.
While the invention has been illustrated and described as embodied in a closure cap for a container, it may be incorporated in any other wall forming portion of the container so as to serve as an indicator of the internal pressure conditions in the container.
I claim: a
1. A closure cap for an hermetically sealed container which cap is adapted to provide audible and visual indication of pressure changes within said container, said cap having a top panel and an integral peripheral skirt with friction means on said skirt for engaging with cooperating means on the container to hold said cap in sealed relation over the mouth of the container, said top panel having a peripheral portion which is in the plane of the top of the cap, an adjacent fiat portion which is in a plane approximately parallel with and downwardly offset relative to the plane of the top of the cap and which is connected to said peripheral portion by a relatively narrow, upwardly and outwardly tapered portion, and an upwardly bowed domeshaped center portion which is connected to the inner periphery ofsaid flat portion by a relatively narrow portion which is tapered upwardly and inwardly of said flat portion, said upwardly bowed center portion having a section in its center area formed on a radius which is larger than the radius of the adjoining section which pressure is applied to the top surface thereof and when said pressure is removed said domed portion will resume its original position.
3. A closure cap for an hermetically sealed container having a panel which forms a wall of the container and a pressure indicating portion in said panel which is joined to an outer peripheral portion thereof by a relatively narrow portion tapering inwardly from said pressure indicating portion toward the inside of the container and outwardly toward the outer periphery of said panel, said pressure indicating portion being normally convex on its outside surface and having a center portion formed as a spherical segment with a predetermined radius of curvature and a surrounding portion extending outwardly of said centerportion which is also formed as a spherical segment with a radius of curvature which is less than the radius of curvature of said center portion, said surrounding portion terminating at said relatively narrow tapered portion, said pressure indicating portion being adapted to be forced into a position in which its outside surface is concave when the pressure on the outside surface thereof exceeds the pressure on the inside surface by a predetermined amount.
4. In a wall forming member of an hermetically sealed container, a panel which is constructed to provide audible and visual indication of pressure changes within said container, said panel having a peripheralportion which is in the outermost plane of said Wall forming member, an adjacent portion which is in a plane approximately parallel with said first mentioned plane and which is offset inwardly of the same, said adjacent portion being connected to said peripheral portion by a relatively narrow, outwardly. tapering band portion, and an outwardly bowed center portion which .is adapted to be flexed inwardly when greater pressure is applied to the outside surface than to the inside surface thereof, said bowed portion being connected to the surrounding portion by a relatively narrow, inwardly tapered band portion, said bowed center forms the outside margin of said upwardly bowed center portion and said upwardly bowed center portion being adapted to flex downwardly when predetermined pressure is applied to the top surface thereof and to snap back into its initial position when the pressure is removed.
2. A closure cap for an hermetically sealed container which is adapted to provide visible indication of pressure changes within said container, said cap having a top panel and an integral peripheral skirt with friction means on said shirt for engaging with cooperating means on the container to hold said cap in sealed relation over the mouth of said container, said top panel having a peripheral portion which is in the plane of the top of the cap, an adjacent relatively narrow flat portion which is in a downwardly offset plane approximately parallel with the plane of the uppermost portion of the cap, and which is connected to said peripheral portion by a relatively narportion being in the form of intersecting spherical sections with the outside surfaces thereof normally convex and with two different radii, and the radius of the center section being larger than the radius of the section at the perimeter of said center portion.
5. In a wall forming member of an hermetically sealed container as recited in claim 4, and said relatively narrow inwardly tapered band portion which connects the bowed center portion with the surrounding adjacent portion being in a plane which diverges in the direction inwardly of the wall forming member from the plane of said surrounding adjacent portion within a range of from 4 to 20 degrees.
References Cited in the file of this patent UNITED STA'II'ESv PATENTS 1,805,623 Hammer May 19, 1931 2,027,430 Hansen Jan. 14, 1936 2,423,295 Crabbe et al. July 1, 1947 2,449,014 Shaifer Sept. 7, 1948 2,458,360 Fay et al Jan. 4, 1949 2,953,272 Mumford et al. Sept. 20, 1960