GB2096116A

GB2096116A - Container and lid

Info

Publication number: GB2096116A
Application number: GB8205900A
Authority: GB
Original assignee: National Plastics Ltd
Current assignee: National Plastics Ltd
Priority date: 1981-02-27
Filing date: 1982-03-01
Publication date: 1982-10-13

Abstract

A plastics container and lid combination is of the type in which the lid 5 has a peripheral skirt 13 which engages around the rim 3 defining the open top of the container. The lid 5 is secured in place by, for example, complementary snap fitting parts 12, 14, and a sealing bead 15 is provided which is compressed between the lid 5 and the container when the lid is secured. In order to avoid damage to the sealing bead 15 by excess pressure used in fitting the lid 5, particularly by machine, at least one abutment 17 is provided on the container wall in the region of the rim 3 for engaging the peripheral skirt 13 of the lid and resisting further movement of the lid towards the base of the container beyond that required to fit the lid. <IMAGE>

Description

SPECIFICATION Container and lid This invention relates to a plastics container and lid combination of the kind in which the container has a base, a side wall or walls, and an open end opposite to the base and defined by a rim, and the lid has a closure part and a peripheral skirt for engaging around the container side wall(s) in the region of the rim, and is secured thereto by the engagement of complementary parts on the peripheral skirt of the lid and on the container side wall(s) in the region of said rim.

One type of seal which is used on such container and lid combinations is an upstanding bead on the container in the region of its rim for engaging the lid when it is secured to the container. An alternative arrangement has the bead formed on the underside of the lid at a position to engage the rim of the container when the lid is fitted. A plastics container and lid combination of the type described and having such a sealing bead is described in our British Patent No. 1,602,818.

Whilst sealing beads of the type described can give satisfactory sealing of the lidded container, one problem which has arisen with such seals occurs during machine fitting of the lid to filled containers when excess machine pressure can permanently distort or otherwise damage the sealing bead to the extent that it no longer gives an effective seal.

According to this invention, a plastics container and a lid combination comprises a container having a base, a side wall or walls, and an open end opposite to the base and defined by a rim; a lid having a closure part for closing the open end of the container and a peripheral skirt for engaging around the container side wall(s) in the region of the rim; securing means for securing the lid to the container comprising complementary engageable parts respectively on the peripheral skirt of the lid and on the outer surface of the container side wall(s) in the region of the rim; sealing means comprising a bead formed on the container in the region of the side wall(s) rim or on the underside of the lid for compression therebetween in a sealing fit when the lid is secured on the container; and an abutment formed on the outer surface of the container side wall(s) in the region of the rim for engaging the peripheral skirt of the lid at a position at which the engagement provides resistance against movement of the lid towards the base of the container beyond that required to secure the lid on the container in a sealing fit.

The abutment preferably is positioned to engage the lower edge of the peripheral skirt of the lid in the manner described.

The outer surface of the container side wall(s) in the region of the rim may be rebated so that the peripheral skirt of the lid can lie at least partly within the rebate when the lid is secured on the container. In this case, the part of the lid securing means which is on the container may be located within the rebate, and the abutment may also be located within the rebate, in a position which is adjacent to said part of the lid securing means and spaced further from the container rim than said part.

For container and lid combinations of circular cross-section, the lid securing means may comprise complementary screw threads formed, respectively, on the inner surface of the peripheral skirt of the lid and on the outer surface of the container side wall in the region of the rim. A preferred securing means, however, comprises complementary parts which engage in a snap fit. For example, a bead may be formed on the inner surface of the peripheral skirt of the lid for engagement with a complementary groove on the outer surface of the container side wall(s) in the region of the rim. A similar result may be achieved by reversing the positions of the bead and groove.

If it is required to lever a snap-fitted lid off the container in normal use by means of a levering tool such as a screw-driver blade, then the rebate in the container side wall(s) should extend below the lower edge of the peripheral skirt of the lid when the lid is secured on the container, in order to provide a gap into which such a levering tool can be inserted.

The abutment may extend around the side wall(s) of the container along a line substantially parallel to the rim. Whilst the abutment may be continuous, it is preferred that it comprises a plurality of discrete abutment portions which are spaced around the side wall(s). In the arrangement where the peripheral skirt of the lid lies within a rebate in the side wall(s) of the container when the lid is fitted, a continuous abutment could prevent access of a levering tool to the lower edge of the peripheral skirt for lid removal purposes, but the spaced abutment portions can provide gaps which allow such access.

Embodiments of the invention are illustrated by way of example by the accompanying drawings, in which: Figure 1 is an elevation, half in section, of a container and its lid, the lid being shown separated from the container, Figure 2 is a fragmental elevation of the top part of the container of Fig. 1 with its lid in position, Figure 3 is a fragmental sectional view, on an enlarged scale, showing the engagement of the lid and container of Fig. 1, Figure 4 is a half plan of the container of Fig. 1 with the lid removed, Figure 5 is a half inverted plan of the container of Fig. 1, and Figure 6 is a fragmental view, on an en larged scale, in the direction of the arrow A in Fig. 1 with the handle omitted.

The container shown in the drawings is circular in plan and comprises a top ring component 1 and a bottom component 2, each moulded in thermoplastics material, for example polypropylene, secured together as will be described by a spun welded joint. The top ring component 1 has a rim 3 defining the open top of the container and having an inwardly and downwardly-extending flange 3a within which the closure part 4 of a lid 5 may be received. The top ring component 1 also has a peripheral seating for the top edge of the bottom component, comprising a downwardly-extending tapered spigot 6 and an outward flange 7 to overlie the top edge of the bottom component and give a neat appearance (see Fig. 3).

The bottom component 2 comprises the base 8 of the container, and extending from the periphery of the base 8, the upstanding, substantially cylindrical side wall 9 of the container, the extremity of which is bevelled, as shown by the reference 10, on its inside edge to match the angle of the tapered spigot 6 of the seating on the top ring component.

The two components 1 and 2 are secured together by the method known as spin welding, a form of friction welding. The tapered spigot 6 of the top ring component is entered into the bevelled end of the side wall part 9 of the bottom component, in which it is a snug fit. One component is then rotated at high speed relative to the other whilst pressing the two components together. The heat generated by friction causes the thermoplastics material to soften in the two contacting surfaces. Rotation is then ceased, allowing the softened material of the two surfaces to fuse together, providing a permanent bond on cooling.

Of course, the two components could be secured together by adhesive, by solvent welding or by heat welding according to wellknown methods. For these purposes the shape of the tapered spigot 6 and the bevel of the side wall part 9 may be altered or these features may even be omitted.

Instead of forming the side wall of the container as a part of the bottom component 2 it may be formed as a part of the top component 1 and the bottom component may be formed with an upward spigot around its periphery similar to the tapered spigot 6, the two components being secured together by a method similar to one of the methods described above.

In another construction, each of the components 1 and 2 may include a side wall part.

Thus the bottom component 2 would have a side wall part of height somewhat less than the desired height of the side wall of the container and the top component would have a complementary side wall part to provide the remainder of the desired height. The two side wall parts would be joined in end-to-end relation, for example by one of the methods described above, their ends being appropri ately shaped, for example bevelled, in known manner.

In yet another construction, part of the height of the container side wall or walls may be provided by a sleeve of thermoplastics material to the opposite end of which the components 1 and 2 are secured by a method similar to of the methods described above.

As shown particularly in Fig. 3, the downward flange forming the closure part 4 of the lid 5 is tapered in section with a feather edge to provide flexibility and good sealing relationship with the inwardly and downwardly-extending flange 3a of the top ring component 1. As previously mentioned and as shown in Fig. 3, the flange forming the closure part 4 is slightly deformed inwardly on engaging the flange 3a, being made of diameter slightly greater than the minimum diameter of the latter for this purpose in order to provide good sealing relationship when the closure is in position.

The top ring component 1 is rebated above the flange 7 with a bevelled surface 11 and a peripheral groove 1 2. The lid 5 has a peripheral skirt 1 3 at the end of which is an inward bead 14 to ride over the bevelled surface 11 and enter the groove 12, giving snap-on retention of the lid.

Instead of the snap-on arrangement described and illustrated the top ring component may have a rebated part above the flange 7 formed with an external screw thread and the lid may have a skirt with a complementary internal screw thread. Alternatively, the top ring component and the lid may have other known complementary features for retaining the lid in position.

Between the skirt 1 3 and the closure part 4 the lid 5 has a narrow downwardly-projecting annular bead 1 5 to engage the rim 3 of the top ring component 1 in sealing relation when the lid 5 is pushed fully home on the container.

Around the shoulder 1 6 defining the lower edge of the peripheral groove 1 2 of the top ring component 1 are a plurality of spaced abutments 1 7 of height somewhat less than the difference between the depth of the periphral groove 1 2 and the depth of the inward bead 14 of the lid. As shown in Figs. 2 and 3, these abutments 1 7 are clear of but very close to the bottom edge of the skirt 1 3 of the lid when the latter is pushed fully home on the container. However, if excessive force is applied to push to lid 5 on to the container, the edge of the skirt 1 3 will engage the abutments 1 7 to resist the force and thus reduce the possibility of crushing or otherwise damaging the narrow annular bead 1 5 which could lead to failure of the bead 1 5 to seal against the top ring component 1 when the force is removed.

It will be understood that the same resistance to excessive force could be provided by reducing the depth of the peripheral groove 1 2 to a dimension only slightly greater than the depth of the bead 14. However, this would lead to difficulty in removing the lid, for which it is necessary to insert a tool into the groove 1 2 to disengage the bead 14 from the groove. The plurality of spaced abutments could be replaced by one or more part-circular abutments extending around a sector or sectors of the shoulder 1 6 and leaving a space or spaces into which a tool can be inserted. The abutments 1 7 shown are, however, preferred, since they permit a tool to be inserted successively at different positions between them for progressive disengagement of the bead 14 from the groove 12.

Buttons 18, 1 9 having headed projections are secured at diametrically-opposite positions to the outer surface of the side wall 9 of the container near its top edge to receive the ends of a bale handle 20 which pivotally engage the headed projections.

As shown in Figs. 1, 4 and 5, the base 8 of the container is supported by a base flange 21 which holds the base clear of any flat surface on which the container is stood. A ring-shaped moulding 22, concentric with the longitudinal axis of the container, is formed in the base 8 in order to reduce the stresses which are set up in the base during the moulding process.

Claims

1. A plastics container and lid combination comprising a container having a base, a side wall or walls, and an open end opposite to the base and defined by a rim; a lid having a closure part for closing the open end of the container and a peripheral skirt for engaging around the container side wall(s) in the region of the rim, securing means for securing the lid to the container comprising complementary engageable parts respectively on the peripheral skirt of the lid and on the outer surface of the container side wall(s) in the region of the rim; sealing means comprising a bead formed on the container in the region of the side wall(s) rim or on the underside of the lid for compression therebetween in a sealing fit when the lid is secured on the container; and an abutment formed on the outer surface of the container side wall(s) in the region of the rim for engaging the peripheral skirt of the lid at a position at which the engagement provides resistance against movement of the lid towards the base of the container beyond that required to secure the lid on the container in a sealing fit.

2. A plastics container and lid combination as claimed in claim 1, in which the abutment is positioned to engage the lower edge of the peripheral skirt of the lid in the manner described.

3. A plastics container and lid combination as claimed in claim 1 or claim 2, in which the outer surface of the container side wall(s) in the region of the rim is rebated so that the peripheral skirt of the lid lies at least partly within the rebate when the lid is secured on the container.

4. A plastics container and lid combination as claimed in claim 3, in which the part of the lid securing means which is on the container is located within the rebate.

5. A plastics container and lid combination as claimed in claim 4, in which the abutment is located within the rebate at a position which is adjacent to said part of the lid securing means and spaced further from the container rim than said part.

6. A plastics container and lid combination as claimed in any of claims 1 to 5, in which the complementary parts of the lid securing means engage in a snap fit.

7. A plastics container and lid combination as claimed in claim 6, in which the rebate extends below the lower edge of the peripheral skirt of the lid when the lid is secured on the container in a sealing fit to provide a gap into which a levering tool may be inserted for lid removal.

8. A plastics container and lid combination as claimed in any of claims 1 to 7, in which the abutment comprises a plurality of discrete abutment portions spaced around the side wall(s) of the container in a line substantially parallel to the rim.

9. A plastics container and lid combination constructed and arranged substantially as herein described with reference to, and as illustrated in, the accompanying drawings.