METHOD AND APPARATUS FOR CLOSING A FILLED, FLANGED CARTON TRAY

Abstract: A method and apparatus for sealing a filled, flanged carton tray with a flat lid. The tray is advanced into a sealing machine while resting on a conveyor means (3) and at random spacing between trays. At a predetermined position the tray has a lid (2) placed on it, the lid (2) engaging against a stop curtain (4) and awaiting the tray (1), this being the lid (2) which is to be sealed against the flanges of the tray. The tray with the lid on it is then advanced by rollers (5-8) into a first microwave applicator (11), which includes longitudinal rails (12, 13) with a C-shaped cross section, for sealing a pair of opposing lid edge portions against respective flanges of the tray (1), subsequent to which, compression or sealing rollers (14-17) situated in the advancing direction of the conveyor means press against the lid (2), which was sealed immediately previously, and before the tray (1) is turned 90 DEG horizontally for sealing in a second microwave applicator (19) the remaining, opposing parts of the lid (2) against the respective flanges on the tray (1).

Description: Method and 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. This has been achieved by a method and apparatus which have the characterizing features disclosed in the accompanying claims. 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 1-2, 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 90° 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.

Claims: CLAIMS 1. Method of sealing a filled, flanged tray with a fla lid, characterized in that the filled tray is fed into sealing machine while resting on a conveyor means and a random spacing between trays, such that a tray comes unde rails on which lids are fed from a magazine, and up to stop curtain situated in the vicinity of the ends of th rails, this curtain also arresting each lid, in that fee rollers situated on either side of the transport mean simultaneously advance a tray with a lid lying on it int coaction with a first microwave applicator, which include a pair of rails with a C-shaped cross section, eac extending round one side part of the lid and one edge flange of the tray, there being one such rail on either side of the conveyor means, in that compression rollers situated after the applicator subsequently press the lid against respective tray flanges simultaneously as the tray is advanced in the machine, and in that after this procedure the tray is rotated horizontally 90°and taken into a second microwave applicator, in which the remaining end wall flanges of the tray are sealed against the respective edge part of the lid, after which the ready- sealed tray is fed out from the machine. 2. Apparatus for sealing a filled, flanged carton tray with the aid of a flat lid and comprising a sealing machine with at least one conveyor means (3) passing through the machine and independent of tray spacing, characterized in that at the beginning of the conveyor means (3), seen in the advancing direction, there is a stop curtain (4) adapted to keep a lid (2) engaged against rails (9, 10) situated above the means (3) and the trays (1) resting thereon, until a tray (1) is advanced under the lid (2), in that there are advancing rollers (5-8) situated a short distance thereafter for advancing a tray (1) with a lid (2) lying on it such that opposing side parts of the lid and the respective flanges on the tray (1) are accommodated in rails (12, 13) with a C-shaped cross section and which are associated with a first microwave applicator (11), for fixing the lid (2) to said flanges of the tray (1), in that pressure or sealing rollers (14-17) are situated after these rails for pressing down the lid (2) before the tray with lid on it comes to a turntable means (18) where the tray is turned 90° horizontally, and in that a second microwave applicator (19) is there adapted in the advancing direction for sealing the remaining opposing flanges of the tray (1) against the lid (2). ■ *

Inventors: WALLIN KAY, WALLIN, KAY
Applicants: SPRINTER SYSTEM AB
Application year: 1987
Main classification: B65B7
IPC codes: B29C65, B65B7, B65B51