GB2213450A

GB2213450A - A sealing device for packaging machines

Info

Publication number: GB2213450A
Application number: GB8830173A
Authority: GB
Inventors: Werner Kmoch; Gunter Muller; Michael Spranger; Ursula Reinhold
Original assignee: Nagema VEB
Current assignee: Nagema VEB
Priority date: 1987-12-30
Filing date: 1988-12-23
Publication date: 1989-08-16
Anticipated expiration: 2008-12-23
Also published as: DE3836057A1; BR8806861A; IT1224848B; IT8848727A0; GB2213450B; JPH01199828A; GB8830173D0; DD269592A1

Description

22 1345 U' 1 A SEALING DEVICE FOR PACKAGING MACHINES The invention relates

to a sealing device for use in packaging machines for producing sealed wrapped packages. The invention is particularly, but not solely, concerned with items of confectionery which are sealed in folded plastics film wrappers.

It is known to wrap articles, such as confectionery items, in plastics f ilm so that the f ilm is wrapped as a U-shaped envelope or cover around each item. The wrappers are then subjected to heat sealing along their overlapping longitudinal edges to provide a tubular cover with end portions projecting outwardly from the article itself. These end portions are then folded, flattened and sealed and then bent back onto the covered surfaces of the article. Apparatus for performing this method is described in DE OS 3420023. The main disadvantage of this apparatus is that the operation is intermittent and cannot match the speed of modern packaging machinery. Furthermore, the sealing tools are expensive.

1 A continuous method and apparatus for heating wrapping_ material in order to stabilise the packaging cover in the fold regions in a take-off wheel while the wrapping material is still being held has also been proposed. This method cannot be used for producing a stable seal for i 2 folded wrappers.

Finally, a further apparatus for sealing folded wrappers has been proposed in which the packaging arrangement is followed by a heating wheel, a turning wheel and a cooling wheel. In this arrangement holding elements arranged in pairs round the peripheries of the wheels co-operate with one another as the wheels revolve.

This apparatus can be used only for outputs of up to about 1000 packages per minute owing to the relatively short heating section of the heating wheel which extends from the position of transfer from the packaging arrangement to the delivery to the turning wheel and, similarly, the relatively short cooling section of the cooling wheel, which extends from the position of transfer from the turning wheel to the delivery station. This apparatus cannot guarantee stable sealed folded edges for the packaging wrappers at outputs of up to about 1500 packages per minute and higher.

An object of the invention is to provide a device capable of producing a more stable seal for the folded edges of the packaging material.

According to the present invention there is provided a sealing device for use in the production of seal-wrapped packaged articles; said device comprising a wheel t51 W j 3 structure rotatable about an axis, a plurality of sets of holding elements arranged around the periphery of the wheel structure, the holding elements of the sets being movable relative to one another to clamp or release the articles which are subjected to heating and/or cooling as the holding elements and articles progress around the rotational axis to seal wrappers containing the articles and camming means for selectively actuating the holding elements at rotational positions where articles are takenup by the device and delivered from the device; wherein there are in total an odd number of sets of holding elements with the camming means being adapted to actuate every other set of holding elements and there are an even number of sets of holding elements between the take-up and delivery locations in the direction of rotation of the wheel structure whereby the articles progress around the rotational axis from the take-up and delivery locations more than once to extend the duration of the heating and/or cooling.

With a sealing device in accordance with the invention a substantially longer heating and/or cooling period can be achieved while maintaining the position of the delivery and take-up stations. It is thus possible to obtain a stable seal for the folded edges of the packaging filni material in the high output range and thus considerably to increase the quality of the packages.

4 The wheel structure can confront a fixed base on which a drive shaft is rotatably mounted. The wheel structure is then fixed to the drive shaft as is a toothed drive wheel between the wheel structure and the base. The camming means may then include rotatable spools with toothed wheels meshing with the drive wheel and driven thereby and cams which actuate mechanisms to open and close the holding elements..

The invention may be understood more readily, and various other features of the invention may become apparent from consideration of the following description.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein:

Figure 1 is a part-sectional side view of a sealing device constructed in accordance with the invention; and Figure 2 is an end view of the device with part of the structure removed, the view being taken in the direction of the arrows B-B of Figure 1.

The sealing device depicted in the drawings takes up prewrapped packaged articles or items with folded plastics film wrappers, for example, containing confectionery. The device forms the sealing station of a packaging machine at which the wrappers are subjected to heating and cooling operations in order to seal the wrappers. As shown, the device has a drive shaft 1 which is rotatablY mounted in a base 2 fixed to a frame of the machine (not shown). A wheel structure or component 4 generally opposite the base 2 is fixed to the shaft 1. Sets of holding devices with complementary holding elements or jaws 11, 11 are mounted to the component 4. There are in all an odd number of sets of holding elements 11, 11'. The elements 11, are mounted on pins or actuators 10 10' slidably journalled in the component 4 and tension springs 12 bias the respective elements 11, ll' together. Between the base 2 and the component 4 there is a chamber in which a toothed drive wheel 3 is disposed. The drive wheel 3 is fixed to the shaft 1. The wheel 3 meshes with further toothed wheels 7, 7 ' of spools rotatably supported on pins 5 mounted to the base 2. The pins 5 are positioned at locations A and U ( Figure 1) where the articles are taken up from a packaging head and delivered once their wrappers have been sealed. The pins 5 extend parallel to the shaft 1. Cam discs 6, 6' are formed integrally with the toothed wheels 7, 7' of the spools. The cam discs 6, 6' co-operate with cam follower rollers 8 supported on rocker levers 9 and associated with the sets of holding elements 10, 10'. The levers 9 are pivotably supported and have toothed portions which mesh with toothed portions of the actuators 10, 10' The gearing and camming arrangement is such that the lobes of the cam discs 6, 6' engage with every other roller 8 passing the locations A and U.

6 The operation of the device is as follows: The shaft 1 rotates together with the drive wheel 3, the wheel structure 4 the sets of holding elements 11, ll' with the actuators 10, 10 and the cam rollers 8 and their rocker levers 9. The cam discs 6, 6' remain in their location but are rotated by the wheel 3. The discs 6, 6' are adjusted to actuate the elements 11, ll' via the rocker levers 9 and the actuators 10, 10 at the positions A and U. but the gear ratio between the drive wheel 3 and the toothed wheels 7, 7' is such that only every alternate other roller 8 is displaced by the cam discs 6, 6' at the locations A and U. When one of the rollers 8 is displaced it pivots the rocker lever 9 to move the actuators 10, 10' to open the holding elements 11, ll' to permit an article to be released or taken up. The springs 12 then bring the elements 11, 11 together as the associated roller 8 moves away from the associated cam disc 6, 6. As the holding elements 11, ll' progress around the axis of the shaft 1, every second pair of elements 11, ll' is loaded with an article at the station U. There are an even number of sets of holding elements 11, ll' between the locations U and A and an odd number of sets of holding up elements 11,11' between the location A and U relative to the direction of rotation. Thence, an article taken up at the location U is retained when the article passes the delivery location A for the first time and is only released when the article reaches the location A for the zi -I -1 7 second time. When an article is removed from a pair of the holding elements 11, ll' at the location A this empty set of holding elements 11, ll' is able to take-up an article when it first.reaches the take-up position U. Because the articles are retained on the device for a longer time the necessary heating and cooling operations performed by appropriate means (not shown) on the wrappers can be made more effective thus creating more reliable seals.

8

Claims

1. A sealing device for use in the production of sealwrapped packaged articles; said device comprising a wheel structure rotatable about an axis, a plurality of sets of holding elements arranged around the periphery of the wheel structure, the holding elements of the sets being movable relative to one another to clamp or release the articles which are subjected to heating and/or cooling as the holding elements and articles progress around the rotational axis to seal wrappers containing the articles and camming means for selectively actuating the holding elements at rotational positions where articles are takenup by the device and delivered from the device; wherein there are in total an odd number of sets of holding elements with the camming means being adapted to actuate every other set of holding elements and there are an even number of sets of holding elements between the take-up and delivery locations in the direction of rotation of the wheel structure whereby the articles progress around the rotational axis from the take-up and delivery locations more than one to extend the duration of the heating and/or cooling.

2. A device according to claim 1, wherein the wheel structure confronts a base on which a drive shaft is -2 1 9 mounted for rotation the wheel structure being fixed to the drive shaft and a toothed drive wheel is also fixed tcb the shaft and is disposed between the wheel structure and the base.

3. A device according to claim 2, wherein the toothed drive wheel meshes with toothed wheels of rotatable spools having cams which serve to actuate rocker mechanisms to move the holding elements together and apart.

4. A device accords to claim 1, 2 or 3, wherein springs bias the holding elements together.

A sealing device substantially as described with reference to, and as illustrated in the, accompanying drawings.

1 Published 1959 atThe Patent Office, State House, 5571 High Holborn, London WCIR4TP. F'urther copies maybe Obtained from The PatentOfnceEWes Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multaplex techniques ltd, St Mary Cray, Kent, Con. 1/87