GB2130564A - Apparatus for heat sealing and crimping a skirted cap on a container - Google Patents

Abstract

In apparatus for heat-sealing a skirted cap on to the lip of a container of glass or other material and to crimp the cap skirt against the exterior of the lip, the heating platen (9) is assembled as a unit with the crimping means (11,12,14), and the unit is detachably secured by a single fixing screw (7) to the block (2) in which the electrical heating element is embedded. Thus, if parts of the apparatus, namely the platen and crimping means which can be contaminated by broken glass or the contents of the container should become so contaminated, they can be readily removed and replaced without removing the heating element or the electrical wiring, thereby reducing production loss. The construction also enables a quick change to be made to alternative heads for sealing different types or sizes of containers. Crimping is effected by radially compressing the skirt of the resilient sealing ring (11) by the radially movable members (12) when the outer ends of the latter engage cam members (18), in the form of vertical leaf springs, upon the unit being pressed against the lip of a container. <IMAGE>

Description

SPECIFICATION Apparatus for heat sealing a skirted cap on a container Our prior British specification No. 1085834 describes an apparatus for heat sealing a skirted cap to a container, and which also mechanically crimps the skirt under the external lip of the container mouth.

The heat sealing of thin metal, e.g. aluminium, foil caps to glass containers presents a number of problems due to the rigidity of the glass compared with plastic materials which will soften or melt down under heat and generally will deform under pressure to conform to the sealing head.

One problem arises if a glass container breaks when sealing with a sealing head as disclosed in specification 1085834. Should this occur the sealing head can become contaminated with glass chippings and/orthe contents of the container, necessitating stopping the production line to enable the head to be cleaned, in some cases requiring the head to be dismantled and reassembled. This can result in high production loss.

Contamination of the sealing head can also arise if a container is presented to the head uncapped or with its contents accidentally overfilled, irrespective of whether the container is of frangible or nonfrangible material.

An object of the invention is to overcome this problem and to provide a sealing head of which the parts which can be so contaminated, namely the heating platen and the crimp seal parts, can be readily replaced without having to remove the heating element or the electrical wiring. The novel construction according to the invention also enables a quick change to be made to alternative heads for sealing different types of sizes of container finish.

To this end, according to one aspect of the invention, apparatus for sealing a skirted cap on a container comprising an electrical heat element in heat-transfer relation to a heating platen to heat seal the top circumference of the cap on the lip of a container and crimping means to mechanically crimp the skirt of the cap under the exterior of the lip of the container, wherein the heating platen is assembled as a unit with the crimping means, the heating platen being detachably secured in heattransfer contact with the heating element of the apparatus, and the crimping means being disposed to be actuated by cam means when the heating platen and heating element move relative to the apparatus by pressing the platen on a container lip.

Another problem is to ensure that the cap is pressed uniformly around its top circumference on to the glass container finish. For this purpose the afore-said specification incorporates a resilient pad on the surface of the heating platen.

Another object of the invention is to improve the heat seal by extending the heat sealed zone beyond the top surface of the container, around the external radius of the container mouth and preferably down as far as the extremity of the cap skirt.

To this end, according to another aspect of the invention, the platen includes a resilient skirted sealing ring which is kept hot by conduction and is adapted to fit over and down the side of the container lip, the skirt of this resilient sealing ring being compressed radially inwardly by actuation of the crimping means to crimp the cap skirt around the exterior of the container lip and simultaneously to heat the cap skirt and seal it around-the container lip.

In order that the invention may be more clearly understood, an embodiment of a sealing head according thereto will now be described with reference to the accompanying drawings, in which: Figure 1 shows a section through the complete head, Figure 2 shows a section through the detachable unit assembly, Figure 3 shows an underneath view of Figure 2, Figure 4 shows a partial section through one segment of the crimping means, and Figures 5a to 5d show a selection of containers which can be sealed with this head.

The complete sealing head shown in Figure 1 is carried buy a mounting plate 1 which may be the turret plate of a multihead sealing machine or part of a single head unit.

A cylindrical block 2 contains an electrical heating element 3 embedded within it so that the whole block can be maintained at the desired temperature by control means (not shown).

The block 2 is free to move upwards against the action of three springs, one of which is shown at 4.

The upward travel is limited when the spacer tube 5 contact the mounting plate 1 and the downward travel is limited by the headed pillars 6.

The easily removable unit of the head comprising a heating platen 9 and crimping means is shown separately in Figures 2 and 3 is also shown in position in Figure 1 fixed to the cylindrical block 2 by the single fixing screw 7 and a location dowel 8. Heat is conducted through the interface and maintains the temperature of the platen 9 at approximately the same as the block 2.

This platen 9 has a recess 10 to locate a resilient sealing ring 11 also kept hot by conduction. The sealing ring 11 is surrounded by a number of segments 12 (six are shown in Figure 3 in which one is shaded to show its shape). The outer portion of each segment is rectangular in cross-section as shown in Figure 4 and is constrained by a radial slot 13 in the platen 9 so that movement of the segments is possible in a radial direction only.

A cover plate 14 retains the segments and the sealing ring in position. The tapered hole in the cover plate serves to guide the container and closure cap into contact with the rubber sealing ring when it is raised into the head or the head is lowered over the container.

A ring made from an open coil spring 15 locates in a groove in each segment 12 and forces them radially outwards to their full extent. If the segments are all pushed in towards the centre of the platen 9, the inside surface of the spring ring 15 contacts the skirt portion of the resilient sealing ring 11 and squeezes it in thus forcing the skirted cap into close contact with the container's exterior mouth portion.

When assembled onto the heated block 2 as shown in Figure 1 each segment is in alignment with a vertical leaf spring 18 fixed at its upper end to a ring 16 on the mounting plate 1. The lower end of the leaf spring is bent outwardly to form an inclined plane or cam surface in contact with the outer extremity of a segment.

Raising the whole assembly with respect to the leaf springs 18 causes each segment 12 to be moved radially inwards thus squeezing the resilient sealing ring 11.

An adjustable band 17 surrounding the leaf springs 18 controls the amountthe segments are pushed in when the segment assembly is lifted to the full extent.

In operation, a glass container with a skirted thin foil cap loosely applied is raised into the head. This seats into the hot sealing ring 11 and lifts the platen 9 and block 2 against the springs 4 which apply top pressure whilst the segments 12 move in applying radial pressure to the cap skirt.

A short dwell at the uppermost position causes the heat sealable coating on the inside surface of the cap to bond to the container rim over the hole of the surfaces in contact.

The resilience of the leaf springs 18 and of the sealing ring 11 enable good seals to be obtained even if the glass surface has irregularities and the container finish has ovality instead of being truly circular. Breakage of containers due to ovality is very unlikely.

On the event of bottle breakage or overspill of container contents, the only part of the head which becomes contaminated will be the platen 9, sealing ring 11 and crimping means 12,15 which are assembled as a unit and can be readily detached and replaced by simply removing the single screw 7.

It is possible to heat seal caps to many different types of glass container finish using this head.

Figures 5a to Sod shows a typical range. A glass drinking tumbler is shown at (a), a container sometimes used to package a product because of its secondary use value.

Ajar with an externally projecting lip is shown at (b).

The container at (c) has a screw thread starting at a level below the cap skirt whilst at (d) the thread runs close to the top of the mouth.

In this latter case the advantage of the skirted sealing ring 11 can be readily appreciated because on one part of the circumference the cap must be sealed over the top of the thread and at another it is sealed on a surface equivalent to the root of the thread.

The leaf springs 18 accommodate this gross difference in radius whilst the resiliant sealing ring 11 accommodates any minor irregularity in all zones.

CLAIMS (Filed on 21/9/83) 1. Apparatus for heat sealing a skirted cap on a container comprising an electrical heating element in heat-transfer relation to a heating platen to heat seal the top circumference of the cap on the lip of a container and crimping means to mechanically crimp the skirt of the cap against the exterior of the lip of the container, wherein the heating platen is assembled as a unit with the crimping means, the heating platen being detachably secured in heattransfer contact with the heating platen and heating element move relative to the means supporting the apparatus by pressing the platen on a container lip.

2. Apparatus according to claim 1, wherein the heating element is embedded in a block of heatconducting material which is free to move upwards, relative to the means supporting the apparatus, against the action of spring means and the heating platen is detachably secured in heat-transfer contact with said block.

3. Apparatus according to claim 2, wherein the platen is secured by a single screw threaded into an aperture in the lowerface of said block.

4. Apparatus according to claim 1,2 or 3, wherein the crimping means includes a skirted sealing ring of resilient material which is in heat-conductive contact with the platen and is adapted to fit over and down the side of the lip of the container to be capped, the skirt of this resilient sealing ring being compressed radially inwardly upon actuation of the crimping means by the cam means.

5. Apparatus according to claim 4, wherein the crimping means includes a plurality of segments surrounding the resilient sealing ring and guided for movement in the radial direction of the sealing ring, a ring made from an open coil forcing the segments radially outwards being located between the inner ends of the segments and the skirt portion of the sealing ring.

6. Apparatus according to claim 5, wherein each segment is in alignment, in the vertical direction of movement platen, with a cam member carried from the means supporting the apparatus which contacts the outer extremity of the corresponding segment when the platen is moved relative to the means supporting the apparatus.

7. Apparatus according to claim 6, wherein each cam member comprises a vertical leaf spring fixed at its upper end to the means supporting the apparatus and having its lower end bent outwardly to form an inclined cam surface.

8. Apparatus for heat-sealing a skirted cap on a container, substantially as hereinbefore described with reference to Figures 1 to 4 of the drawings.

9. Apparatus for heat-sealing a skirted cap on a container comprising an electrical heating element in heat-transfer relation to a heating platen to heat seal the top circumference of the cap on the lip of the container, wherein the platen includes a resilient skirted sealing ring which is kept hot by conduction and is adapted to fit over and down the side of the container lip, the skirt of this resilient sealing ring being compressed radially inwardly by actuation of the crimping means to crimp the cap skirt around the exterior of the container lip and simultaneously to heat the cap skirt and seal it around the container lip.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. shown in Figure 1 each segment is in alignment with a vertical leaf spring 18 fixed at its upper end to a ring 16 on the mounting plate 1. The lower end of the leaf spring is bent outwardly to form an inclined plane or cam surface in contact with the outer extremity of a segment. Raising the whole assembly with respect to the leaf springs 18 causes each segment 12 to be moved radially inwards thus squeezing the resilient sealing ring 11. An adjustable band 17 surrounding the leaf springs 18 controls the amountthe segments are pushed in when the segment assembly is lifted to the full extent. In operation, a glass container with a skirted thin foil cap loosely applied is raised into the head. This seats into the hot sealing ring 11 and lifts the platen 9 and block 2 against the springs 4 which apply top pressure whilst the segments 12 move in applying radial pressure to the cap skirt. A short dwell at the uppermost position causes the heat sealable coating on the inside surface of the cap to bond to the container rim over the hole of the surfaces in contact. The resilience of the leaf springs 18 and of the sealing ring 11 enable good seals to be obtained even if the glass surface has irregularities and the container finish has ovality instead of being truly circular. Breakage of containers due to ovality is very unlikely. On the event of bottle breakage or overspill of container contents, the only part of the head which becomes contaminated will be the platen 9, sealing ring 11 and crimping means 12,15 which are assembled as a unit and can be readily detached and replaced by simply removing the single screw 7. It is possible to heat seal caps to many different types of glass container finish using this head. Figures 5a to Sod shows a typical range. A glass drinking tumbler is shown at (a), a container sometimes used to package a product because of its secondary use value. Ajar with an externally projecting lip is shown at (b). The container at (c) has a screw thread starting at a level below the cap skirt whilst at (d) the thread runs close to the top of the mouth. In this latter case the advantage of the skirted sealing ring 11 can be readily appreciated because on one part of the circumference the cap must be sealed over the top of the thread and at another it is sealed on a surface equivalent to the root of the thread. The leaf springs 18 accommodate this gross difference in radius whilst the resiliant sealing ring 11 accommodates any minor irregularity in all zones. CLAIMS (Filed on 21/9/83)

1. Apparatus for heat sealing a skirted cap on a container comprising an electrical heating element in heat-transfer relation to a heating platen to heat seal the top circumference of the cap on the lip of a container and crimping means to mechanically crimp the skirt of the cap against the exterior of the lip of the container, wherein the heating platen is assembled as a unit with the crimping means, the heating platen being detachably secured in heattransfer contact with the heating platen and heating element move relative to the means supporting the apparatus by pressing the platen on a container lip.

2. Apparatus according to claim 1, wherein the heating element is embedded in a block of heatconducting material which is free to move upwards, relative to the means supporting the apparatus, against the action of spring means and the heating platen is detachably secured in heat-transfer contact with said block.

3. Apparatus according to claim 2, wherein the platen is secured by a single screw threaded into an aperture in the lowerface of said block.

4. Apparatus according to claim 1,2 or 3, wherein the crimping means includes a skirted sealing ring of resilient material which is in heat-conductive contact with the platen and is adapted to fit over and down the side of the lip of the container to be capped, the skirt of this resilient sealing ring being compressed radially inwardly upon actuation of the crimping means by the cam means.

5. Apparatus according to claim 4, wherein the crimping means includes a plurality of segments surrounding the resilient sealing ring and guided for movement in the radial direction of the sealing ring, a ring made from an open coil forcing the segments radially outwards being located between the inner ends of the segments and the skirt portion of the sealing ring.

6. Apparatus according to claim 5, wherein each segment is in alignment, in the vertical direction of movement platen, with a cam member carried from the means supporting the apparatus which contacts the outer extremity of the corresponding segment when the platen is moved relative to the means supporting the apparatus.

7. Apparatus according to claim 6, wherein each cam member comprises a vertical leaf spring fixed at its upper end to the means supporting the apparatus and having its lower end bent outwardly to form an inclined cam surface.

8. Apparatus for heat-sealing a skirted cap on a container, substantially as hereinbefore described with reference to Figures 1 to 4 of the drawings.

9. Apparatus for heat-sealing a skirted cap on a container comprising an electrical heating element in heat-transfer relation to a heating platen to heat seal the top circumference of the cap on the lip of the container, wherein the platen includes a resilient skirted sealing ring which is kept hot by conduction and is adapted to fit over and down the side of the container lip, the skirt of this resilient sealing ring being compressed radially inwardly by actuation of the crimping means to crimp the cap skirt around the exterior of the container lip and simultaneously to heat the cap skirt and seal it around the container lip.