Patent Application
20130082065
The invention relates to storage containers such as are commonly used for food storage where the storage container comprises a container such as a plastic bowl or dish for retaining the stored product and a matching plastic cover that snap fits onto the container to create a liquid and/or air tight seal. The containers typically come in a variety of sizes to give the user a choice in the size of container used based on the size of the product being stored. One issue with such containers is the difficulty for the user in storing the containers and lids such that the user may easily locate a desired container and the matching lid. One such system is the Easy Find Lids system sold by Newell Rubbermaid Inc.
A glass container system comprises a glass container and lid. The glass container comprises a base that defines a bottom of the container and a sidewall formed integrally with the base to define an interior space. A protuberance is formed integrally with the base where the protuberance extends beyond a side wall of the base. The lid is dimensioned such that the protuberance engages the lid such that the lid may be releasably secured to the base.
The protuberance may extend beyond the side wall of the base less than 1 mm and approximately 0.25 mm. The glass container may comprise a plurality of protuberances. The plurality of protuberances may be spaced about the base. The system may further comprise a second glass container where the second glass container may be dimensioned to nest in the glass container. The lid may comprise a lip where the lip is releasbly engageable with the protuberance such that the lid may be releasably secured to the base.
A glass container made by a process comprising the steps of providing a mold having a mold cavity defining a container having a base at a bottom of the mold cavity where the mold cavity comprises an undercut portion that defines a recess in the mold cavity; introducing molten glass to the mold such that the glass fills the recess of the undercut portion to create a protuberance on the base; cooling the glass to cause the glass to shrink a sufficient amount that the protuberance withdraws from the recess; and removing the container from the mold in a linear upward direction.
The process may further comprise the step of lubricating the mold cavity before each step of introducing molten glass. The process may further comprise the step of flame treating the container without distorting the protuberance. The step of cooling may comprise running coolant over the mold in the area adjacent to the base and recess. The coolant may comprise air. The step of cooling may comprise adequately running coolant over the mold. The process may further comprise the step of tempering the glass.
The following detailed description refers to the accompanying drawings, which illustrate specific embodiments of the invention. Other embodiments having different structures and operation do not depart from the scope of the present invention. Like reference numbers refer to like structures throughout.
Referring to
Referring to
The top of the lid 14 is provided with an inwardly facing lip or series of lips 30 that are engaged by the base 4 of the container 2 such that the base 4 of the container 2 may be secured to the top of the lid 14. By securing the base 4 of the container 2 to the lid 14 the user can store a lid with the like sized container. The lip 30 is formed as part of the molded plastic rim portion 14a on an upwardly extending annular flange 32. The annular flange 32 extends above the top surface of the lid such that the lip 30 is spaced from the top surface of the lid a sufficient distance to receive the base 4 of the container 2. A protuberance or series of protuberances 40 formed on the base 4 (
The lid 14 is are also provided with an outwardly facing protuberance or a series of lips 50 formed on the bottom of the rim portion 14a that are releasably engageable with the lips 30 such that the lids may be secured to one another as well as to the base 4 of container 2. The lips 50 are formed at the bottom side of the rim portion 14a and are located such that the lips 50 are disposed opposite to the lips 30 when one lid 14 is placed on top of another lid 14. The lips 50 and lips 30 are both made of molded plastic and are deformable such that both elements can deform to releasably engage one another. To store the containers 2 and lids 14, the containers may be nested inside of one another with the base of the outermost container 2′ secured to a first lid 14′ and the remaining lids 14″ secured to one another and to the first lid as shown in
Referring to
In order to be able to engage the lips 30 the protuberances 40 must extend beyond the wall portion 4a of the base 4 a predetermined distance to provide sufficient surface area against which the lips 30 can bear. In one embodiment the protuberance 40 extends beyond the wall portion 4a less than 1 mm and approximately 0.25 mm. The extent the protuberance 40 extends beyond the wall 4a is limited by the manufacturing tolerances associated with molding a glass article having an undercut portion as described herein. The container system described herein provides a glass container having undercut protuberances to be used with a deformable lid such that the lid may be releasably attached to the base 4 of the glass container using the protuberances 40.
Referring to
It is to be understood that in glass molding operations the mold 60 and plunger 61 are one-piece structures. The article is removed from the mold by retracting the plunger 61 from the mold 60. The mold 60 is not otherwise disassembled to remove the molded glass article from the mold. The molded glass article 2 is removed in an upward linear fashion from the mold 60 through opening 64 as represented by arrow A. One problem with a molded glass article is that any protuberance formed near the bottom of a molded glass article or formed in a position where the protrusion extends beyond the portion of the article located above the protuberance in the mold cannot be easily removed from the mold 60 because the molded glass protuberance will tend to strike the undercut area of the mold causing the glass article to fracture or chip. Referring to
In order to avoid breaking the article yet still provide a glass container 2 that has protuberances 40 on the base 4, the manufacturing process of the invention has been developed.
As glass cools it shrinks slightly. The present invention takes advantage of this shrinkage by dimensioning the protuberance 40 such that the length the protuberance that extends beyond the wall portion 4a and accordingly the length L of the undercut portion 66 is selected to be approximately the same or less than the amount of shrinkage of the glass as it cools. As a result, as the glass cools the base 4 and protuberance 40 shrink to the point that the glass protuberance 40 is withdrawn from the recess 67 and the distal end of the protuberance 40 will clear the undercut area 66 when the container 2 is removed from the mold 60 (Block 605). In one embodiment the distance the protuberance 40 extends beyond wall 4a is less than 1 mm and may be approximately 0.25 mm although the absolute amount of shrinkage in linear distance will vary based on the size of the container and the amount of glass in the base 4.
To control the cooling of the molded glass container and to ensure that the base 4 cools sufficiently to obtain the desired shrinkage a plurality of cooling stations, Stations 3 through 6, are provided prior to releasing the container from the mold. The cooling stations run coolant over the mold 60 in the area adjacent to the base 4 to cool the base 4 sufficiently to cause the desired shrinkage (Block 606). The coolant may comprise air, water or other coolant blown or sprayed over and/or through the mold adjacent to at least the base 4 of the container 2. After the cooling stations the table 70 indexes the mold 60 and container 2 to Station 10 where the container 2 is removed from the mold 60 (Block 607).
Even with the appropriate cooling and shrinking, the tolerances necessary to make the protuberances work properly with the lid are very small. Because the protuberance extends for less than 1 mm and may be approximately 0.25 mm, the total dimension D (
Finally, because the dimension D of the base has a small tolerance in order to be able to attach to the lids 14, a fire polishing or flame treatment step of the glass molded article to smooth the finish of the container 2 is provided such that the protuberances are not distorted during the flame treatment step. For example, as shown in
The polished containers 2 may then be introduced to a tempering oven 72 where the glass is tempered as is known (Block 610). The heat tempered articles may then be air cooled, sprayed with a food safe spray and inspected (Block 611).
Although specific embodiments have been illustrated and described herein, those of ordinary skill in the art appreciate that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiments shown and that the invention has other applications in other environments. This application is intended to cover any adaptations or variations of the present invention. The following claims are in no way intended to limit the scope of the invention to the specific embodiments described herein.
