Patent EA-000805-B1 (EA)
Title: Cans or group of cans for food products with a hygeinic protection, method and protection therefor
Inventor: GROPPI SILVANO
IPC: B65D71/50
Filed: 1997-07-09
Abstract: 1. A capping method for cans having an. upper portion formed from the substantially flat cop end of the can, its upper frusco-conical neck and. the circular rim which joins the flat top end to the neck, comprising the steps of placing a portion of film of thermoformiable plastic material on the upper portion of the can in contact with the upper border of its rim, to define a closed chamber in combination with said upper border of the rim; softening by heating the portion of the film limited to the area aligned with the top of the can; pushing by a forming plate the film against the can top so that the softened area of the film is above the top of the can, and the unsoftened area snaps around and beneath the upper rim of the can, characterized in that the film is heated to a suitable temperature such that the film is able to satisfy the conditions of thermoformability; the air is extracted from said chamber; and by hardening following cooling the film adheres intimately to the surface or the can which it covers and retains its shape. 2. A can capping method as claimed in claim 1, characterized in that the plastic material film is heated before being placed on the upper portion of the can. 3. A can capping method as claimed in claim 1, characterized in that that film portion adhering to the upper portion of each can is separated by cutting along a closed line which closely surrounds said upper portion. 4. A can capping method as claimed in claim l, characterized in that that film portion adhering to the upper portion of at least two cans is separated by cutting along a closed line which closely surrounds on the outside the line constituting the envelope o<= said upper portion of the at least two cans. 5. An apparatus for capping cans having an upper portion formed from the substantially flat top end of the can, its zipper frusco-conical neck and the circular rim which joins the flat top end to the neck, comprising a carrier for advancing at least one can through said machine, a plastic sheet supply, a heather for softening said plastic sheet and means for moving said sheet into contact with the upper portions of the cans, characterized by further comprising: at least one tray provided with recesses as-ranged to each receive at least one can; an overlying backing/centering plate with a plurality of through apertures, each arranged to receive, with slight clearance, the upper portion of the at least one can contained in each of said recesses; means for arranging said tray in correspondence with said backing/centering place in a position such that the upper portion of each can contained in the tray recesses projects beyond the upper surface of the backing/centering place; means for softening by heating a web of plastic film; means for arranging the softened web of plastic film above the backing/centering plate and above the projecting upper portions of the cans; grid means defining a corresponding plurality of apertures, each arranged to surround a corresponding aperture of the centering plate, the lower edge of said grid means being arranged to press the film against the upper surface of the centering plate; between said centering plate and said tray, pneumatic seal means which surround the recesses each containing at least one can; means for putting the chambers formed by the recesses and the overlying film under vacuum; and means for cutting said film in proximity to the outer edge of said through aperture of the centering plate. 6. An apparatus for capping cans according to claim 5 characterized by each recess arranged to receive at least two cans being provided with a partitioning baffle which occupies the apace left free between the outer walls of the cans and the inner wall of the recess. 7. An apparatus as claimed in claim 5, characterized in- that the pneumatic seal means consist of an annular gasket. 8. An apparatus as claimed in claim 5, characterized in that the pneumatic seal means act between the backing/centering plate and the neck of the can. 9. An apparatus as claimed in claim 5, characterized in that the pneumatic seal means act between the backing/centering plate and the tray. 10. An apparatus as claimed in claim 5, characterized by comprising yieldable presser means for pressing the plastic film against the upper end of the cans. 11. An apparatus as claimed in claim 5, characterized by comprising, in correspondence with each aperture of the centering plats, a sleeve of hard material against which the film cutting means act. 12. An apparatus as claimed in claim 5, characterized in that the film cutting means are a plurality of vertically movable cylindrical blades, the cutting edge of which faces downwards and has a closed contour arranged to circumscribe at a short distance therefrom the edge of the through aperture of the centering plate. 13. An apparatus as claimed in claim 5, characterized in chat the blade cutting edge rests en the sleeve to act as a punch. 14. An apparatus as claimed in claim 5, characterized in that the blade cutting edge enters the sleeve to act as shears. 15. A container can for food products and drinks comprising a single portion of film which mates with and covers the surface of the can upper portion, characterized in that the films a thermoformable plastic film, substantially rigid at room temperature so that the cap can be removed from the cam upper portion without breaking and can be reapplied to the can upper potion by elastically snapping under the cam rim. 16. A covered top can package for a group of cans consisting of a single portion or film which covers the upper portion of each can of the group and mates with the whole surface of the top of each can, the lid included.