Reclosable containers are convenient and easily loadable packages which are advantageously used when it is desired to repeatedly access a product within a container, or more commonly when a package with a positive locking closure is needed which may be easily loaded and sealed without the need for adhesives or sealing tools. These containers are commonly thermoformed of thin thermoplastic material and have a bottom portion or base and a top lid or cover. To keep the container closed after initial opening, it is necessary to provide some means of interlocking the cover and the base. A common type of interlocking structure employs projections and depressions on shoulders extending from the cover and base which engage with each other in a "snap" fit. The cover and the base are thus held together during normal usage but may be pulled apart by applying sufficient force.
To avoid unwanted opening of the container, it is advantageous to have a tight seal between the cover and the base. However, if the seal is too tight it will require excessive force to reopen the container. This difficulty in opening is compounded by the fact that with a standard snap fit closure the separating force must be applied by pulling the top cover and base in opposite directions. With containers that are too large or too small to be easily grasped, even greater difficulties in opening will be encountered.
The problem of producing a container with a tight reliable seal, yet that is easy to open, is long standing in the art and has evoked many different approaches to solution. What is needed is an easily manufactured package that may be securely closed yet easily opened.