Heat sealing machine

Claim 2

Apparatus for applying covers to peripherally flanged trays, said apparatus being of the type which comprises conveyor means for advancing a series of spaced trays, means for applying and sealing a cover web to the tray flanges, and knife means for severing the cover web between adjacent trays; the improvement wherein said conveyor means comprises fixed, laterally spaced longitudinal rails for slidably supporting the side flanges of each tray, an endless moving conveyor having a reach that passes between said rails, and transverse flights on said conveyor, the upper surfaces of said flights being flush with the upper surfaces of said rails along said conveyor reach for supporting the end flanges of adjacent trays, each of said flights being formed to provide a full length recess for receiving a blade of said web severing knife means.

Claim 3

In a packaging machine of the type including a tray conveyor for supporting a file of trays having peripheral upper flanges, said conveyor advancing the trays along with a continuous covering web past sealing and cutting stations where the web is sealed to the tray flanges and is then transversely severed to produce individual covered trays, the improvement wherein said tray conveyor comprises a pair of driven endless chains, a plurality of equally spaced transverse flights interconnecting said chains for supporting the trailing and leading flanges of adjacent trays carried by the upper reach of said chains, each of said transverse flights having an upwardly open longitudinal recess intermediate the confronting edges of adjacent tray flanges for receiving a knife blade that severs the covering web, and a fixed support rail at each side of said upper conveyor reach having an upper surface for slidably supporting the lateral flanges of said trays.

Claim 4

In a packaging machine of the type including a tray conveyor for supporting a file of trays having peripheral upper flanges, said conveyor advancing the trays along with a continuous covering web past sealing and cutting stations where the web is sealed to the tray flanges and is then transversely severed to produce individual covered trays, the improvement wherein said tray conveyor comprises a pair of driven endless chains, a plurality of equally spaced transverse flights interconnecting said chains for supporting the trailing and leading flanges of adjacent trays carried by the upper reach of said chains, each of said transverse flights having an upwardly open longitudinal recess intermediate the confronting edges of adjacent tray flanges for receiving a knife blade that severs the covering web, and a fixed support rail at each side of said upper conveyor reach having an upper surface for slidably supporting the lateral flanges of said trays.

Claim 5

In a multiple lane heat sealing machine including two side by side continuously driven chain conveyors each having an upper reach for advancing a file of trays having horizontally projecting peripheral flanges, the improvement comprising a common fixed support rail between and parallel to said conveyors for slidably supporting the longitudinally extending inner flanges of laterally adjacent trays, a fixed support rail at the side of each conveyor for supporting the outer longitudinal tray flanges, a plurality of spaced transverse flights mounted on the chains of each conveyor, each of said flights supporting both the leading and trailing flanges of adjacent trays and having an upwardly open grove intermediate said flanges, means for supplying a cover web for the trays on each conveyor, a presser roll mounted over each of said conveyors for bonding the associated web onto the flanges of underlying trays, an overhead knife drum mounted downstream of each presser roll on a common driveshaft extending over both of said conveyors, and a plurality of knife blades carried by each knife drum for movement in a circular path downward into said support flight grooves for severing the cover webs between successive trays.

Claim 6

In a multiple lane heat sealing machine including two side by side continuously driven chain conveyors each having an upper reach for advancing a file of trays having horizontally projecting peripheral flanges, the improvement comprising a common fixed support rail between and parallel to said conveyors for slidably supporting the longitudinally extending inner flanges of laterally adjacent trays, a fixed support rail at the side of each conveyor for supporting the outer longitudinal tray flanges, a plurality of spaced transverse flights mounted on the chains of each conveyor, each of said flights supporting both the leading and trailing flanges of adjacent trays and having an upwardly open grove intermediate said flanges, means for supplying a cover web for the trays on each conveyor, a presser roll mounted over each of said conveyors for bonding the associated web onto the flanges of underlying trays, an overhead knife drum mounted downstream of each presser roll on a common driveshaft extending over both of said conveyors, and a plurality of knife blades carried by each knife drum for movement in a circular path downward into said support flight grooves for severing the cover webs between successive trays.

Claim 7

A heat sealing machine comprising a continuously driven tray conveyor for trays having a planar peripheral flange around a receptacle, a pair of laterally spaced fixed longitudinal rails for slidably supporting the lateral flanges of said trays, transverse flights movable with said conveyor extending between said longitudinal rails for supporting the leading and trailing flanges of the trays, said flights each having a longitudinal central groove opening to its upper surface and disposed between the confronting flanges of two adjacent trays, a heated presser roll having a lower surface substantially coincident with the upper surfaces of said rails, means for supplying a continuous web of thErmoplastic material intermediate said presser roll and the trays in covering relation with said tray flanges, said presser roll heating and intimately engaging the web with said tray flanges to bond the web to said flanges, a plurality of knife blades, and means mounting said knife blades for movement in a circular path downward into each passing groove in said support flights to sever the web intermediate each two adjacent trays.

Claim 8

A heat sealing machine comprising a continuously driven tray conveyor for trays having a planar peripheral flange around a receptacle, a pair of laterally spaced fixed longitudinal rails for slidably supporting the lateral flanges of said trays, transverse flights movable with said conveyor extending between said longitudinal rails for supporting the leading and trailing flanges of the trays, said flights each having a longitudinal central groove opening to its upper surface and disposed between the confronting flanges of two adjacent trays, a heated presser roll having a lower surface substantially coincident with the upper surfaces of said rails, means for supplying a continuous web of thErmoplastic material intermediate said presser roll and the trays in covering relation with said tray flanges, said presser roll heating and intimately engaging the web with said tray flanges to bond the web to said flanges, a plurality of knife blades, and means mounting said knife blades for movement in a circular path downward into each passing groove in said support flights to sever the web intermediate each two adjacent trays.