Automatic packaging method and apparatus with heat-sealing elements having resilient heat conducting members

Claim 1

In automatic packaging apparatus of the type including means for supporting cup-shaped containers having peripheral flanges around the open mouths thereof; a sealing station; means for transporting said supported container into and through said sealing station; means for supplying to each container a sheet of material to serve as a top for the container; and means at said sealing station for heat-sealing the top to the container flanges to produce hermetically sealed packages, said heat-sealing means including first means to engage and support the under surface of the container flange during the heat-sealing operation; that improvement of said packaging apparatus wherein the sealing station further comprises: resilient means mounted for relative reciprocal movement towards and away from said first means and arranged to press the top and the adjacent portion of the cup flange together against said first means with at least a moderate degree of sealing pressure; heat conducting means forming part of said resilient means to provide substantially enhanced conduction of heat through said resilient means to the engaged surface thereof pressed against said top; the engaged surface of said resilient means being sufficiently flexible to conform under said sealing pressure to irregularities presented by the flange surface of the container and to effect a close, intimate, heat-transferring contact between said resilient means, said top, and said container flanges throughout a region extending entirely around said flanges; and means to supply heat to said resilient means for conduction through said heat conducting means to raise said engaged surface to an Elevated temperature, said heat supply means and said heat conduction means cooperating to supply through said resilient means all of the heat required to seal said top to said flanges and providing effective heat-sealing thereof.