MULTI-FIT CAP

Abstract

A screw cap for sealing containers with threaded necks includes an outer body, having a cylindrical outer wall closed at one end by a circular lid and an interior neck seal adjacent to the circular lid. A female thread extends around an inner surface of the cylindrical outer wall. The female thread has a main portion having substantially uniform thickness, and an attachment portion having a thickness which is less than the thickness of the main portion. The female thread is attached to the inner surface of the cylindrical outer wall in the region of the attachment portion, and the attachment portion is configured to permit deflection of the female thread.

Claims

1. A screw cap for sealing a container with a threaded neck, the screw cap comprising: an outer body, comprising: a cylindrical outer wall closed at one end by a circular lid, and an interior neck seal adjacent to the circular lid; and a female thread extending around an inner surface of the cylindrical outer wall, the female thread comprising: a main portion having substantially uniform thickness, and an attachment portion having a thickness which is less than the thickness of the main portion; wherein the female thread is attached to the inner surface of the cylindrical outer wall in the region of the attachment portion, and wherein the attachment portion is configured to permit deflection of the female thread.

2. The screw cap according to claim 1, formed of a moulded polymer material.

3. The screw cap according to claim 2, wherein the moulded polymer material is selected from one or more of the group consisting of: HDPE, LDPE, polyamide or polyacetal.

4. The screw cap according to claim 1, wherein the thickness of the attachment portion is between 90% and 50%, between 80% and 60%, or more preferably between 75% and 67% of the thickness of the main portion.

5. The screw cap according to claim 1, wherein the attachment portion has a length that is more than 5% and no more than 33%, more than 5% and no more than 20%, or between 10% and 15% of a total length of the female thread.

6. The screw cap according to claim 1, wherein the main portion comprises an inclined region that extends from the attachment portion in a direction away from the lid of the outer body.

7. The screw cap according to claim 6, wherein the inclined region extends from the attachment portion at an angle of between 10 and 65, between 20 and 55 or between 30 and 45.

8. The screw cap according to claim 7, wherein the main portion further comprises an end portion which extends from the inclined region at an angle, such that the end portion is substantially parallel to the lid of the outer body.

9. The screw cap according to claim 8, wherein the end portion has a length that is between 10% and 40%, or between 25% and 33% of the total length of the female thread.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is a side perspective view of a typical jug bottle neck.

[0019] FIG. 2a is an external side view of a screw cap according to an embodiment of the present invention, in engagement with a bottle neck.

[0020] FIG. 2b is a schematic cross-sectional view through section A-A of FIG. 2a.

[0021] FIG. 3 is a schematic cross-sectional representation of the thread area of a screw cap according to an embodiment of the present invention, in engagement with a bottle neck.

[0022] FIG. 4 is a detail of a cross-section of the thread area of the screw cap of FIG. 3, showing exemplary dimensions.

DETAILED DESCRIPTION

[0023] FIG. 1 shows a typical jug bottle neck 100 of diameter E. The neck has a male thread 102 of diameter T. Diameters E and T can vary by up to 5% of their nominal dimensions depending on the manufacturer.

[0024] FIG. 2a shows a screw cap 200 according to an embodiment of the present invention, in engagement with a bottle neck 100 such as the one shown in FIG. 1.

[0025] FIG. 2b shows a cross-sectional view through section A-A of FIG. 2a. The screw cap 200 comprises an outer body, which comprises a cylindrical outer wall 204 closed at one end by a circular top or lid 206, and a female thread 208 extending around an inner surface 210 of the cylindrical outer wall 204. The female thread 208 is shown in engagement with the male thread 102 of the bottle neck 100.

[0026] The female thread 208 comprises an attachment portion 212 and is attached to the inner surface 210 in the region of the attachment portion 212. The female thread 208 further comprises a main portion, which consists of an inclined region 214, extending downwardly from the attachment portion 212 (i.e. away from the lid of the cap 206), and an end portion 216, extending from the inclined region 214 to the free end 213 of the female thread 208. The end portion 216 extends from the inclined region 214 at an angle, so that it is approximately parallel with the lid of the cap 206.

[0027] The attachment portion 212 has a reduced thickness compared with the main portion, which allows the female thread 208 to deflect as it interconnects with the male thread 102 of the bottle neck 100. This in turn allows the end portion 216 to align with and fully engage between the ridges of the male thread 102, without requiring accurate matching of the cap to the dimensions of E and T (see FIG. 1), ensuring a secure seal when the cap 200 is completely closed.

[0028] The cap 200 comprises a neck seal 220, in the form of a liner around the lid 206. In use, the cap 200 is fully tightened so that the mouth of the bottle 218 is completely sealed against the neck seal 220.

[0029] FIG. 3 shows a cross-sectional representation of the screw cap 200 according to an embodiment of the present invention, zoomed in on the threads 208, 102. The attachment portion 212 has a reduced thickness relative to the rest of the female thread 208 and acts like a hinge, allowing the thread 208 to deflect when in engagement with the male thread 102. The thickness of the narrow region is approximately 70% of the thickness of the rest of the female thread 208.

[0030] FIG. 4 shows a detail of the cross-section of the female thread of the screw cap 200, with typical dimensions in millimetres for an example thread. It will be appreciated that these dimensions are shown for illustrative purposes only. Screw caps of different sizes, formed of different materials, or suitable for different applications, may have dimensions that vary considerably from those shown. As shown, the thread 208 extends at an angle from the inner surface of the outer wall 204 to a distance (total length, C) of 6.0 mm. The main portion 214 has a substantially uniform thickness (A) of 1.25 mm. The attachment portion 212 has a thickness (B) of 0.87 mm (a reduction in thickness of about 30% compared to the main portion) and extends to a length (D) of 0.8 mm (about 13% of the total length of the female thread). The end portion 216 has a length (E) of 1.8 mm (about 30% of the total length of the female thread). Also as shown, 0.5 mm radius fillets are provided where the thread 214 joins the inner surface of the outer wall 204, as well as other radiuses on the outer form of the thread 208.