Rotary heat-sealing and cut-off mechanism

Claim 1

A packaging machine for enclosing articles in individual packages by heat-sealing webs of thermoplastic material over the top of an open tray containing the articles to be packaged which comprises, in combination: a. a carrier movable to convey longitudinally and sequentially a series of open top trays containing the articles to be packaged, b. web feeding means for conveying a continuous web of thermoplastic material over the tops of said trays, c. heat-sealing means positioned downstream of said web feeding means for sealing said web to the top edges of said trays as they are sequentially conveyed under said heat-sealing means, said heat-sealing means including a heated drum mounted on and rotatable with an axle having an axial bore, said drum extending transversely of said web and having at least one cavity extending axially and radially therethrough, d. cut-off means operable from within said heat-sealing means to sever transversely said continuous web between successive trays, said cut-off means including a blade mounted axially within said cavity near the periphery of said drum and being biased radially inwardly thereof, a first cam means extending axially within the bore of said axle and adapted to reciprocate selectively in an axial direction, and a second cam means connected to said blade and extending radially into the interior of the bore of said axle through slots provided therein at the base of said cavity, said first cam means being operable to engage and disengage said second cam means to move said blade radially outwardly and inwardly from the periphery of said drum, respectively.

Claim 9

An apparatus for applying covers from a continuous cover strip to rim top containers comprising, conveyor means having a plurality of container support frames shaped to support a container, means on the machine for positioning a cover strip in overlying relation to the containers in the frames and with one end of the cover strip at a selected location along the conveyor means, a combination rotary sealing and cutting head at said location having a sealing face on its periphery and cutting means extending outwardly from the periphery of the sealing head and pitched around the head a distance corresponding to the pitch of the container support frames on the conveyor means, and means for rotating said sealing and cutting head at a peripheral speed corresponding to the linear speed of said conveyor means whereby said head progressively seals the cover strip to a container rim as it is advanced and severs the cover film between adjacent containers.

Claim 10

An apparatus for applying covers from a continuous cover strip to rim top containers comprising, conveyor means having a plurality of container support frames shaped to support a container, means on the machine for positioning a cover strip in overlying relation to the containers in the frames and with one end of the cover strip at a selected location along the conveyor means, a combination rotary sealing and cutting head at said location having a sealing face on its periphery and cutting means extending outwardly from the periphery of the sealing head and pitched around the head a distance corresponding to the pitch of the container support frames on the conveyor means, and means for rotating said sealing and cutting head at a peripheral speed corresponding to the linear speed of said conveyor means whereby said head progressively seals the cover strip to a container rim as it is advanced and severs the cover film between adjacent containers.