Punch stripper ring knock-out for pressware die sets

Abstract

In a pressware die set, a segmented punch for fabricating a pressed disposable food service article having a substantially planar bottom portion, a sidewall and a rim portion. In one embodiment, the punch is mounted to reciprocate cyclically between an open position and a forming position about an axis of reciprocation and includes outer punch surfaces for forming the sidewall and rim portions of the pressed disposable food service articles, as well as a substantially planar punch surface suitably mounted and dimensioned to engage the substantially planar bottom portion of the disposable food service article. The improved punch includes a knock-out stripper ring juxtaposed with the substantially planar punch surface, defining a knock-out surface and which is reciprocally mounted with respect to the central substantially planar punch surface such that the knock-out surface is contiguous with the substantially planar punch surface when the punch is in a forming position. The knock-out surface of the knock-out stripper member projects axially from the substantially planar punch surface when the punch reciprocates towards its open position. The knock-out surface area is generally from about 3 to about 50% of the area of the substantially planar surface of the punch.