GB2026993A

GB2026993A - Crimping-on Device

Info

Publication number: GB2026993A
Application number: GB7921329A
Authority: GB
Original assignee: Nyffeler Corti AG
Current assignee: Nyffeler Corti AG
Priority date: 1978-06-20
Filing date: 1979-06-19
Publication date: 1980-02-13
Also published as: FR2429155A1; ES481360A1; DE2918429A1; GB2026993B; FR2429155B1; DE2918429C2; CH636814A5

Abstract

A crimping-on device in apparatus for affixing and sealing a flat film or foil (9) to a container rim (3), comprises a sealing head (4) consisting of a sealing socket (7) surrounding a sealing tool (5). The sealing socket is in turn surrounded by crimping tool (11), the bottom edge of which projects inwardly and has a guide surface (13). Held between this guide surface and the underside of the sealing socket (7) is an annular elastic crimping member (15) which, upon upwards movement of the crimping tool (11) relative to the sealing socket (7), is pushed into the neck-groove (2) by the guide surface (13). Sealing tool (5) is guided in the sealing socket (7) for resilient movement in line with the axis of the container, and the sealing socket (7) and the crimping tool (11) can be moved up and down independently of one another in line with the axis of the container (1). <IMAGE>

Description

SPECIFICATION Crimping-on Device in Apparatus for Affixing a Film or Foil to the Rim of a Container This invention relates to the sealing of containers, and more particularly to a crimping-on device in apparatus for affixing a film or foil to the rim of a container, as well as a method of operating the device.

Apparatus has already been proposed for attaching a foil, coated on the underside with a thermoplastic material, to the rim of a container by applying pressure and heat. Such apparatus comprises a sealing head movable in line with the axis-of the container and having on the underside thereof cup-spring blades projecting obliquely outwards, these blades being intended and adapted to rest upon the portion of foil to be affixed to the container rim and to roll this portion of foil onto the container rim.

Moreover, crimping-on devices have already been disclosed, e.g. in the specifications of French Patent No. 1,320,268, German Patent No.

809,381, Belgian Patent No.498,230, and U.K.

Patent No. 426,609, wherein a crimping member is pressed into a neck-groove adjacent to the container rim by the relative movement of crimping tools.

However, all of these prior art crimping-on devices require preshaped foils, i.e. such as have the edge already bent down and, in particular, must not have any pull-tab projecting at right angles to the axis of the container. The reason is that if such a pull-tab were present, one of the axially movable crimping tools would strike against the top of the tab and thereby tend to tilt the lid formed by the foil, leading to crumpling on the side opposite the pull-tab, and this is to be avoided.

Thus, there is a need for a device aliowing the use of flat foils with pulltabs for the container closure, without having to put up with the risk of the lid's being lifted off and crumpled, and without having to bend the edge of the foil beforehand.

In accordance with the present invention, there is provided a crimping-on device in apparatus for affixing a film or foil to the rim of a container, adjacent to the neck-groove thereof, the apparatus comprising a sealing head movable parallel to the axis of the container, the sealing head comprising a sealing socket surrounding a sealing tool, the sealing socket being in turn surrounded by a socket-shaped crimping tool, the lower edge of which projects inwardly and includes a guide surface running obliquely downwards on the upper side thereof, a crimping member in the form of an elastic annular spring being held between the guide surface and the underside of the edge of the sealing socket, the annular ring being pressed by the guide surface into the neck-groove of the container upon an upward movement of the crimping tool relative to the sealing socket, characterized in that the sealing tool is guided within the sealing socket for resilient movement parallel to the axis of the container, and that the sealing socket and the crimping tool are movable up and down independently of one another in the direction of the axis of the container.

A preferred embodiment of the invention will now be described in detail, by way of example, with reference to the accompanying drawings, the three figures of which are cross-sections through this embodiment in three different phases of operation.

A container 1 to be sealed, preferably made of glass or plastics, has an upper neck portion which passes into a bulging rim 3 at a neck-groove 2. A sealing head 4 surrounds a heatable sealing tool 5, which can move up and down in line with the axis of the container 1, as well as a spring element 6 and a sealing socket 7. Attached to the underside of the sealing tool 5 are cup-spring blades 8, directed obliquely outwardly and downwardly, which, in a manner of no further interest in this context, upon a downward movement of the sealing head 4, roll the edge of a foil 9, coated with the thermoplastic material, laid over the mouth of the container 1, and extending somewhat beyond the container rim 3, over and onto the rim 3 for the purpose of sealing the container 1.

The sealing tool 5 is connected to the floor of the sealing socket 7 by a spring element 6 which, in the embodiment illustrated, takes the form of a number of superposed cup-springs. The sealing socket 7 comprises walls 7a surrounding the sealing tool 5 on all sides. The height of the walls 7a is such that when there is no load on the spring element 6 (Figure 1), the free edges of the walls 7a are still situated above the surface formed by the underside of the sealing tool 5.

Secured to the floor of the sealing socket 7 are two drive rods 10 which can be moved up and down parallel to the axis of the container 1 in a manner not shown, e.g. by pneumatic means, these movements being transmitted to the sealing tool 5 via the spring element 6.

The rods 10 pass through the floor of a likewise socket-shaped crimping tool 11, the sidewalls 11 a of which similarly surround the sealing socket 7 on all sides. Connected to the floor of the crimping tool 11 is a drive rod 12 disposed parallel to the rods 10, so that the crimping tool 11 and the sealing head 4 can each move up and down independently of one another, but parallel to the axis of the container 1.The free lower edge of the walls 11 a of the crimping tool -11 is provided on the inside with an inwardly and downwardly inclined conical guide surface 13 which forms an angle of between 200 and 450 to the horizontal, The height of the walls 11 a is such that in the resting state, i.e. when neither the sealing head 4 nor the crimping tool 11 is being driven (Figure 1), a space 14 remains between the lower bounding surface of the walls 7a and the guide surface 13. Inserted in the space 14 is an annular, radially elastic crimping member 15 which may take the form of a spiral spring or a split spring ring.

The mode of operation of the device described above is as follows: In the starting position shown in Figure 1, the relative positions of the sealing tool 5 of the sealing socket 7, the crimping tool 11, and the container 1 are such that a plane running at right angles to the container axis through the free lower edge of the wall 11 a lies above a similar plane running through the container rim 3, while the lower end face of the sealing tool 5 lies above the plane through the edge of the wall 11 a or below that through the free lower edge of the wall 7a. In this starting position, the oblique cupspring blades 8 rest upon the thermoplasticcoated foil 9 lying on the container rim 3, so that the blades 8 hold the foil 9 firmly against the rim 3.

It is the task of the cup-spring blades 8 to hold the foil 9 thus firmly against the rim 3 even if the latter exhibits considerable surface irregularities, as is generally true of glass containers. In the case of containers having smooth, even rims, e.g.

plastics containers, the provision of such cupspring blades is superfluous as far as the crimping operation is concerned, for the foil is held securely to the container rim just by the sealing tool 5, resiliently guided within the sealing socket 7 by means of the spring element 6.

Starting from the position shown in Figure 1, the first phase of operation consists in lowering the sealing head 4 and the crimping tool 11 together, the spring element 6 being simultaneously compressed, until the foil 9 has been rolled onto the container rim 3, the edge of the foil 9 being brought into a position substantially parallel to the axis of the container 1 by the crimping member 1 5 situated beneath the wall 7a, and the lower inner edge of the crimping tool 11 pointing substantially towards the neckgroove 2 (Figure 2). The crimping tool 11 is now moved upwards alone, so that the crimping member 1 5 bears against the free edge of the sealing wall 7a and is pushed by the slope of the guide surface 13, counter to the natural bias of the member 15, into the neck-groove 2.The edges of the foil 9 are thereby tucked under the bulging container rim 3 on all sides and forced into the neck-groove 2, whereupon the crimping operation is ended (Figure 3).

If the crimping tool 11 is now lowered once more, i.e. if the apparatus is returned to the position shown in Figure 2, the crimping member 1 5, owing to its elasticity, withdraws from the neck-groove 2 and reaches the position illustrated in Figure 2, from which it once more attains the resting position shown in Figure 1 by means of the joint upwards movement of the sealing head 4 and the crimping tool 11, in which resting state all of the parts have regained their starting positions.

The crimping-on device described above, in conjunction with the described apparatus for affixing a film or foil, makes it possible not only to carry out the crimpingon in a single operation together with the sealing operation, and thereby substantially to facilitate and shorten the entire closure process, but also to use flat closure foils with pull-tabs, without having either to pre-bend the edges of the foil or to put up with the risk of the lid's lifting off or crumpling.

Claims

1. A crimping-on device in apparatus for affixing a film or foil to the rim of a container, adjacent to the neckgroove thereof, the apparatus comprising a sealing head movable parallel to the axis of the container, the sealing head comprising a sealing socket surrounding a sealing tool, the sealing socket being in turn surrounded by a socket-shaped crimping tool, the lower edge of which projects inwardly and includes a guide surface::running obliquely downwards on the upper side thereof, a crimping member in the form of an elastic annular spring being held between the guide surface and the underside of the edge of the sealing socket, the annular ring being pressed by the guide surface into the neckgroove of the container upon an upward movement of the crimping tool relative to the sealing socket, characterized in that the sealing tool is guided within the sealing socket for resilient movement parallel to the axis of the container, and that the sealing socket and the crimping tool are movable up and down independently of one another in the direction of the axis of the container.

2. A method of operating the device of claim 1, characterized in that the sealing socket and the crimping tool are lowered together towards the container until cup-spring blades of the sealing tool lie resiliently upon the rim of the container, in that the sealing socket and the crimping tool are then moved farther downward together, the sealing tool remaining stationary, until the lower edge of the sealing socket is situated substantially opposite the neck-groove of the container, and in that the crimping tool is then moved upwards, the sealing socket and the sealing tool remaining stationary, whereby the crimping member is pressed along the oblique guide surface into the neck-groove.

3. A crimping-on device substantially as hereinbefore described with reference to the accompanying drawings.

4. A method of operating a crimping-on device substantially as hereinbefore described with reference to the accompanying drawings.

5. Apparatus for affixing a film or foil to the rim of a container, comprising a crimping-on device substantially as hereinbefore described and claimed.