Method and apparatus for closing a thin-walled container body

#This invention relates to methods and apparatus for closing an open end of a thin-walled, hollow container body, by application of a diaphragm which is adhered to the can body across the open end.

#This specification will concern itself particularly with metal cans, but it is to be understood that the thin-walled container may be of any material (such as plastics or paperboard) suitable for use as a container for use by a consumer and for containing products which may typically be perishable, such as foodstuffs. The term "thin-walled" indicates that the walls of the container body are sufficiently thin to be likely to have randomly uneven contours. The wall will also, typically, have significant flexibility.

#For some years there has been a requirement for a metal can which is hermetically sealed but which has a readily openable top to enable a consumer to gain access to the contents of the can without generating potentially harmful ragged metal edges. One proposal has been to seal one end (the top) with a diaphragm which is adhered to a rim formed on the can body. Such a can would be produced by the can manufacturer with an open bottom and the product manufacturer would invert the can, fill it and then close the bottom by conventional means, for example using a rigid metal base and a rolled double seam.

#A method and apparatus therefor, according to the present invention, will now be described by way of example only, with reference to the drawings hereof, in which:

#FIG. 1 is a simplified perspective view of an apparatus according to the invention;

#FIG. 2 is an elevation, partly in section, of a diaphragm cutting and forming device provided at a diaphragm feed station illustrated in FIG. 1;

#Referring to FIG. 1, the illustrated apparatus basically comprises a fixed support 10 adjacent to which is mounted a heater 12, and analog which a succession of can bodies 14, open at both ends, are conveyed to an indexing transfer turret 16. The turret 16 is arranged to carry the bodies 14 to a diaphragm feed station 18, where diaphragms are cut from a web 20 and are brought into initial contact with a curled rim 22 at the open upper end of each can body 14. A sealing station 24 is situated downstream of the diaphragm feed station 18, for finally sealing the diaphragms to the can bodies, whilst a discharge station 25 is provided beyond the sealing station 24.

#In order to convey the can bodies 14 along the support 10, a drive belt 26 is provided above and to one side of the support and is mounted about a pair of wheels 28 having vertical axes. One wheel 28 is driven by means not shown and the other is freely rotatable. The belt 26 co-operates with a fixed guide 30, disposed above and at an opposite side of the support 10, to advance the bodies 14 whilst rotating them. The heater 12 comprises an array of gas jets 32 mounted over the guide 30 and directed so that as the bodies are advanced along the support 10 their rims 22 are heated.

#A fixed support 34 is disposed at the level of the support 10 to receive the bodies 14 once their rims have been heated. The turret 16 is disposed above the support 34 and has a pair of circular plates 36, provided at intervals about their circumferences with pockets 38 within which the bodies 14 are engageable, to carry the bodies in spaced relation to each successive station 18, 24, 25. A guide bar 40 retains the bodies 14 in the pockets 38.