GB2200099A - Container and cap therefor - Google Patents

Abstract

The container (18) has a neck (12) with an external screw thread (16), ihe neck being closed by a membrane (15) fused to its rim (13). A cap is secured on the neck and is unscrewable therefrom. The cap can be unscrewed from the neck, inverted and re-engaged on the-neck for rotation. The top (20) of the cap carries a cutting formation (36) which cuts the membrane on rotation of the cap. The periphery of the cap carries an upstanding cam lobe (31) which engages the screw thread (16) on the neck to lift the cap during its rotation so that the membrane is not completely severed and remains attached to the rim when the neck has been opened. <IMAGE>

Description

CONTAINER AND CAP THEREFOR This invention relates to a container and a cap therefor.

It is often important to ensure that the contents of a container, such as a bottle, are sealed within the container by secondary closure means and a membrane is often sealed to the rim of a container over its mouth, the membrane being protected by a cap, which engages with a peripheral portion of the container and is the primary closure means. The membrane may serve to protect the contents of the container from the atmosphere, e.g. on coffee jars, or may serve to protect users from the contents, e.g. in the case of dangerous chemicals. The membrane ensures that there can be no leakage past the cap and also protects the person removing the cap from contact with any of the chemical.

The membranes are usually held within the cap, so that when the cap is applied to the container, the membrane contacts the rim of the container. The membrane is transferred to the rim by means of an adhesive, or by induction transfer, whereby heat is induced in a conductive layer in the membrane and fuses a thermoplastic layer of the membrane to the rim.

It is necessary to open the membrane to gain access to the contents. It is known to provide a cutting formation on top of the cap, so that the inverted cap can be engaged with the container rim and rotated to sever the membrane. This has the problem that the membrane falls into the interior of the container where it may partially obstruct removal of the contents and thereby cause splashing of the contents, or may be transferred with the contents to machinery where obstruction or damage may be caused. With dangerous chemicals, it is extremely difficult safely to remove a severed membrane.

It is possible to leave the membrane secured to the rim over a short arc, so that the problem is avoided. In practice, however, it is difficult to assess how far to rotate the cap to achieve this end. The length of arc remaining secured to the rim must not be too short, so that it can twist or become detached as the contents are dispensed. The length of arc must not be too long either, since the membrane will not then readily hinge to allow the contents to be dispensed. The cutting formation is not, however, visible during the severing operation.

The present invention avoids this problem and permits the membrane to remain secured to the rim over a predetermined length of arc, without need for any skill.

The present invention provides a container with a removable cap, the container having a portion provided with a mouth delimited by a rim and closed by a membrane secured to the rim, the cap having a top and a skirt and being secured to said portion of the container to enclose the membrane, the skirt and said portion being adapted to permit separation of the cap from the container by relative rotation thereof, the top of the cap being externally provided with a cutting formation, whereby the cap can be inverted and rotated relative to the container so that the cutting formation severs the membrane from the rim, and camming means on the cap and on said portion of the container, the camming means co-acting to separate the cutting formation from the membrane for a predetermined length of arc during a complete revolution of the cap relative to the container in a severing operation, whereby the substantially severed membrane remains joined to the rim along said predetermined length of arc.

The camming means on the cap may comprise a lobe and the camming means on the container portion may comprise a peripheral projection on which the lobe rides. The peripheral projection may be a part of a screw thread which is engageable with a formation on the inner periphery of the skirt of the cap for screw-separation of the cap from the container.

The top of the cap may have a peripheral guide member engageable with the rim for guiding rotation of the cap relative to the container in a severing operation, the cam lobe being defined by an axial extension of the guide member.

The cutting formation preferably has a blade edge concentric with the skirt and extending over a short arc 0 less than 0 of less than 20 (advantageously less than 15 ) to facilitate penetration of the membrane by the blade edge.

It is preferred that two such arcuately spaced formations are provided having oppositely facing blade points facilitating severing of the membrane in either direction of relative rotation between the- cap and the container.

The invention also resides in a cap for use with a container having a portion provided with a mouth, delimited by a rim, with an external peripheral screw thread and with a membrane sealed to the rim and closing the mouth, the cap comprising a top, a skirt having an internal formation for engaging the screw thread on the container to secure the cap thereto and permit removal of the cap, a cutting formation provided externally on the top of the cap, whereby the cap can be inverted and rotated in engagement with the rim of the container to sever the membrane, and camming means on the cap arranged so as to ride on the screw thread of the container in a severing operation, the camming means and the cutting formation being relatively sized so that the camming means lifts the cutting formation, as it rides on the screw thread, to leave a predetermined length of the membrane joined to the rim.

Reference is now made to the accompanying drawings, wherein Figure 1 is a perspective view showing a cap and container combination with the cap in severing mode; and Figure 2 is a perspective view of the cap mounted on the container in a closure mode.

The container 11 shown may be a plastics moulding having a neck 12 provided with a rim 13 and a mouth 14.

The mouth is closed by a membrane 15 fused to the rim by induction transfer from the interior of the cap. The neck has an external peripheral screw thread 16 adjacent the rim and an annular projection 17 between the thread 16 and the bqdy 18 of the container. The cap has an internal screw thread 20 by which the cap can be screwed onto and off the neck.

The cap (Figure 2) is provided with an integral tamper-evident ring 21 which engages the annular projection 17 and becomes separated from the rest of the cap as it is screwed off the container.

The rim is captivated on the neck (Figure 1) and its detachment from the rest of the cap indicates that the contents may have been tampered with.

The cap has a top 25 and a skirt 26, the latter having the internal screw thread 20 and being initially integral with the tamper-evident ring 21. The top is provided with a peripheral, annular projection 27 whose inner diameter is complementary to the outer diameter of the rim 13. The cap can, be inverted and the external surface of the top engaged on the membrane 15 on the rim 13, so that the rim is received within the annular projection 27 to guide relative rotation of the cap and the container. Spaced radially inwardly of the projection 27 is a cutting device 30 which cuts the membrane from the rim during such rotation.

The annular projection 27 has an axially extending portion defining a cam lobe 31. This lobe is sized such that it engages the top portion of the screw thread 16 on the container. As the cap is rotated, in the mode shown in Figure 1, the cam lobe rides along the screw thread and the depth of the lobe is such that, for a short predetermined arc, the cutting device is lifted out of contact with the membrane 15. This occurs as the lobe rides over the end portion of the thread nearest to the rim 13. As a result, the membrane is severed from the rim, except for the short arc where the cutting device is lifted out of contact with the membrane.

The cutting device 30 comprises two cutting members 35, 36 spaced angularly and projecting from the top of the cap. Each cutting member is integrally moulded with the cap and comprises a blade edge 37 extending over 0 about 10 of arc, concentric with the skirt of the cap, and an axially extending blade edge 38 between the other blade edge 37 and the top of the cap. The blade edges meet at a point 39. The two cutting members having blade points 39 which face in opposite directions.

This arrangement facilitates penetration of the membrane at the initiation of rotation of the cap on the container in a severing operation. The cap can be rotated in either direction, with one or the other of the cutting members 35, 36 operating, depending on the direction of rotation.

It is envisaged that a special camming member can be provided on the neck 12 to engage the cam lobe 31, instead of using the screw thread 16. This may be appropriate if an arrangement other than screw threads is used to mount the capon the container. The peripheral projection 27 may be omitted.

Claims (9)

1. A container with a removable cap, the container having a portion provided with a mouth delimited by a rim and closed by a membrane secured to the rim, the cap having a top and a skirt and being secured to said portion of the container to enclose the membrane, the skirt and said portion being adapted to permit separation of the cap from the container by relative rotation thereof, the top of the cap being externally provided with a cutting formation, whereby the cap can be inverted and rotated relative to the container so that the cutting formation severs the membrane from the rim, and camming means on the cap and on said portion of the container, the camming means co-acting to separate the cutting formation from the membrane for a predetermined length of arc during a complete revolution of the cap relative to the container in a severing operation, whereby the substantially severed membrane remains joined to the rim along said predetermined length of arc.

2. A container with a removable cap as defined in Claim 1 wherein the camming means on the cap comprises a peripheral projection on which the lobe rides.

3. A container with a removable cap as defined in Claim 2, wherein said peripheral projection is part of a screw thread which is engaged with a formation on the inner periphery of the skirt of the cap permitting screwseparation of the cap from the container.

4. A container with a removable cap as defined in Claim 1, 2 or 3 wherein the top of the cap has a peripheral guide member engageable with the rim for guiding rotation of the cap relative to the container in a severing operation and wherein the cam lobe is defined by an axial extension of the guide member.

5. A container with a removable cap as defined in any preceding - claim, wherein the cutting formation has a blade edge concentric with the skirt and extending over a short arc of less than 200.

6. A container with a removable cap as defined in Claim 5, comprising two said arcuately spaced cutting formations having oppositely facing blade points to facilitate severing of the membrane in either direction of relative rotation between the cap and the container.

7. A container with a removable cap as defined in Claim 5 or 6, wherein said short art is less than 150.

8. A cap for use e with a container having a portion provided with a mouth, delimited by a rim, with an external peripheral screw thread and with a membrane sealed to the rim and closing the mouth, the cap comprising a top, a skirt having an internal formation for engaging the screw thread on the container to secure the cap thereto and permit removal of the cap, a cutting formation provided externally on the top of the cap, whereby the cap can be inverted and rotated in engagement with the rim of the container to sever the membrane, and camming means on the cap arranged so as to ride on the screw thread of the container in a severing operation, the camming means and the cutting formation being relatively sized sp that the camming means lifts the cutting formation, as it rides on the screw thread, to leave a predetermined length of the membrane joined to the rim.

9. A cap constructed substantially as herein described with reference to the accompanying drawings.