Apparatus for Closing a Filled, Flanged Carton Tray

The present invention relates to a method and apparatus for closing a filled, flanged carton tray with the aid of a flat lid.

The machines used today for sealing such packs have been found to be both expensive in manufacture and operation as well as in maintenance.

The object of the present invention is to provide a machine which is cheap to produce and to operate, with the aid of which a filled tray can be sealed very efficiently.

The present invention relates to a method and apparatus for sealing lids onto cartons, the apparatus including: conveying means for conveying the cartons without regard to the spacing between the cartons; lid applying means for applying the lids onto the cartons; heat generating means for generating heat to fix the lids to the cartons; pressing means for subsequently pressing the lids against the cartons; turning means for subsequently turning the cartons; and further fixing means for subsequently further fixing the lids to the cartons.

Preferably, the conveying means includes a belt conveyor. Preferably, the belt conveyor includes a short feed section for conveying the cartons toward the lid applying means, the conveying means including a second belt conveyor for conveying the cartons from the lid applying means.

Preferably, the lid applying means includes moving means for moving the lids to a lid applying position above the conveying means. Preferably, the lid applying means includes stopping means for stopping each of the lids until a respective one of the cartons is located below the lid applying position. Preferably, the apparatus includes transferring means for transferring the lids and the cartons to the heat generating means. Preferably, the stopping means is actuated by the cartons to release the lids from the stopping means. Preferably, the stopping means includes a stop curtain. Preferably, the moving means includes rails. Preferably, the transferring means includes rollers.

Preferably, the heating means includes a microwave applicator. Preferably, the microwave applicator includes rails, the rails being C-shaped so as to accommodate the lids and the cartons.

Preferably, the pressing means includes rollers.

Preferably, the turning means includes means for horizontally rotating the cartons through 90.degree..

Preferably, the further fixing means includes a microwave applicator.

The invention will now be described in more detail below with reference to the accompanying drawings, on which

FIG. 1 is a schematic plan of a sealing machine in accordance with the present invention,

FIG. 2 is a schematic perspective view of a part of the machine illustrated in FIG. 1, this part being at the approach end of the machine seen in the advancing direction of the tray,

FIG. 3 is a schematic side view of the approach part seen in the direction of tray advance of the machine illustrated in FIG. 1, and also shows the part of the machine illustrated in FIG. 2.

The machine illustrated on the drawings has at least one conveying means 3 passing through it for advancing and simultaneously sealing flanged trays 1, which have been filled somewhere else. The trays 1 are advanced with no particular spacing on the conveyor means 3 and come into the forward part of the machine, seen in the advancing direction of the trays 1, and up to a position in front of a stop curtain 4, against which a lid 2 is already lying in wait for the tray 1 it is to seal. The lid 2 is supplied from a magazine 20 situated above the conveyor means 3, and is supported in position above the carton by longitudinal rails 9, 10 situated along and above the means 3 and the trays 1 on said means 3. When the lid 2 is situated directly above a tray 1 below it, both are simultaneously advanced by rollers 5, 6, 7, 8 situated on either side of the means 3. Tray and lid are advanced together to a first microwave applicator 11, which includes C-shaped rails 12, 13 on either side of the conveyor means 3. The flanges of the tray and the sealing edges of the lid are accommodated in the gaps of the rails 12, 13 and sealed together with the aid of microwaves. After the applicator 11 there are pressure rollers 14, 15, 16, 17 intended to press the sealed flange and lid parts together before the tray 1 is advanced to a turntable means 18, where the tray 2 is turned horizontally through an angle of 9O.degree. to enable sealing the remaining flanges of the tray 1 to the lid or vice versa, with the aid of a second microwave applicator 19, which is situated after the turntable means 18 but before a discharge part of the machine. The second microwave applicator 19 is formed similar to the first one, and operates in the same way. In the illustrated embodiment, the conveyor means 3 is made up from standard belt conveyors, and comprises two sections, a short feed section and a section for remaining steps in the machine. A rotary principle is used for transferring the lids from the magazine 20. Setting-up for different tray sizes can be done manually within a period of 30 minutes.