Tray-shaped article having smooth edges and amenable to multiple film sealing methods
AssigneeConverter Manufacturing, LLC
InventorMillard F Wallace
Life of this patent
Estimating the term…
Abstract
The disclosure relates to forming shaped thermoplastic articles having smooth peripheries. Many thermoplastic articles have sharp edges formed upon molding or cutting the article from a feedstock sheet. Such sharp edges can damage thin plastic films or flesh which they contact, and smoothing the edges is desirable. Described herein are methods of forming a smooth periphery for such sharp-edged articles by rolling over the sharp edge. The smoothing operation is performed by forming a deflectable flange including a bend region separated from the potentially sharp peripheral edge by a spacer, deflecting a portion of the deflectable flange, and softening at least one bent portion of the deflectable flange to yield a smooth periphery upon cooling.
Claims29
A tray intended to be suitable for use in any or all of overwrap (OW), vacuum-sealed packaging (VSP), and modified atmosphere packaging (MAP) sealing technologies, the tray being;
- an article formed from a thermoplastic sheet having a peripheral edge, the article comprising a tray-shaped body having a concave portion surrounded by an extension extending peripherally away from the concave portion;
- the extension including the peripheral edge, a flat sealing surface surrounding the concave portion and being suitable for sealing a sealing film thereto using either of VSP and MAP sealing technologies, a bend region adjacent the sealing surface and interposed between the peripheral edge and the sealing surface, the bend region having the conformation of a smooth curve, and a bent portion interposed between the peripheral edge and a spacer separating the bent portion from the bend region;
- and
- the article having a smooth periphery and having the overall shape of a rectangular tray with rounded corners, and the bent portion being bent sufficiently that the peripheral edge is turned at least approximately opposite the periphery.
Dependencies are inferred from the claim text.