This invention relates to a device for removing a screw-threaded cap and particularly to a device suitable for removing a cap of a child resistant container. Many medicines are very dangerous if taken in excess of the prescribed quantity. For this reason it is essential to keep medicines away from young children, and in many countries legislation requires prescription medicines to be dispensed in a child resistant container (CRC) . The usual kind of CRC for medicines is a conventional screw-threaded bottle having a special cap which can be opened only by applying a degree of dexterity and force. CRC caps are often of a push and twist variety where the user must push down an outer cap against a resilient member to engage unscrewing teeth of an inner cap. If the outer cap is not pushed down it rotates freely or may make a clicking noise as teeth ratchet over one another.

CRC's have reduced the danger to children substantially, but the elderly and infirm often have great difficulty in opening a push and twist CRC cap because they do not have the required dexterity. This is especially true of persons suffering from arthritis. Whilst it is possible for a patient to request a conventional cap when the medicine is dispensed, many patients accept a CRC because they do not know that conventional caps are sometimes permitted, or they are frightened that the medicine will not be secure if not in a CRC.

The present invention concerns a device to aid the elderly and infirm in opening a push and twist CRC cap. The device is also suitable for opening conventional screw caps which may have been tightly applied to a container. A particular problem with caps for medicine bottles is that the outside diameter may vary slightly from one manufacturer to another notwithstanding that the caps appear to have the same nominal diameter. This is usually because the cap specification is concerned with the size of the bottle neck rather than the exterior dimension.

According to the present invention there is provided a device for removing a screw threaded cap from a screw threaded neck of a vessel, the device having a body, a recess within the body adapted to receive at least a portion of the circumference of a cap, and a lever arm extending to one side of the body, the recess having a plurality of substantially equispaced inwardly directed ribs extending generally axially thereof, the inner edges of said ribs defining a substantially circular boundary adapted to engage about the periphery of the cap with which the device is to be used, wherein the ribs are stepped inwardly to accommodate caps of successively smaller external diameter, and wherein the ribs taper inwardly to accommodate marginally different caps which are nominally of the same external diameter.

The taper of the ribs is determined by the particular dimensions of the caps of nominally the same external

diameter which are to be received within the device. Preferably the taper is as small as possible so as to maximise purchase of the ribs on a cap. Typically the taper angle is less than 20°, and is preferably in the range 2- 15° and most preferably less than 10°. The taper of each step of the device may differ.

A large taper is disadvantageous since the device may engage only the corner of the cap, and insufficient torque will be generated.

In the preferred embodiment six substantially identical equispaced ribs are provided. The device is preferably a one piece plastics moulding, e.g. of filled polypropylene, polystyrene or ABS, these materials having the required degree of rigidity for the ribs.

The device may accommodate two sizes of cap but is preferably adapted to receive three or four different diameters of cap.

The recess is preferably blind and generally circular in plan. In a preferred embodiment the recess is substantially part-spherical.

Preferably each step of each rib tapers inwardly. In the preferred embodiment, the inner edge of the ribs is angled to increase the purchase of the device on the cap in use. The rib steps may for example have substantially radial parallel sides terminating at a non- perpendicular inner edge, the ribs being wider on the side which leads in use. The knife edge formed thereby is

adapted to engage a cap, and particularly the usual axially extending serrations of a cap. In one alternative the ribs may be substantially triangular in section, the bisector of the apex pointing generally in the clockwise direction when viewed from below.

Preferably the device is adapted to be held in one hand, the recess being generally aligned with the users palm, and the lever arm being engageable by the ends of the users fingers. In the preferred embodiment the device has an upper side adapted to the contours of a human hand.

The lever arm need not be a radially extending protrusion; a non-circular form which allows sufficient torque to be generated by the user is sufficient.

Preferably the lever arm includes one or more edge recesses adapted to receive one or more respective fingers.

In the preferred embodiment four such recesses are provided each comprising a generally semi-circular groove substantially parallel to the axis of said recess.

Preferably the device is symmetrical, and thus usable by left and right handed users.

Other features of the invention will be apparent from the following description of a preferred embodiment shown by way of example only with reference to the accompanying drawing in which: Fig. 1 is a side elevation of the device;

Fig. 2 is a view of the underside of the device; Fig. 3 is a section on line 3-3 of Fig. 2, and

Fig. 4 is a partial section illustrating the device in use.

With reference to the drawings, the hand held cap removal device 10 comprises a one piece plastic moulding having a smooth and continuous outer surface 11 and a hollow underside. The outer surface is adapted to the contours of the human hand so as to be a generally comfortable fit.

A substantially circular cap receiving recess 12 is defined in the underside of the device at one side, the axis of the recess being generally aligned with the palm of a users hand in use.

One side of the device is formed with a series of four shallow grooves 13 which extend around the top of the device and merge gently into the region above the recess 12. The grooves 13 define finger recesses so that the device may be gripped comfortably in one hand.

Each side of the device is formed with two further grooves 14,15 which extend up the side of the device at an angle to merge into the palm region above the recess 12. These additional grooves constitute additional finger or thumb receiving recesses.

As clearly illustrated in Fig. 3, a plurality of stiffening ribs 16 extend between the edge of the circular recess 12 and the node on either side of grooves 13.

The recess 12 has a gently tapering mouth and six equispaced and inwardly directed ribs 17. Each rib is identical and has four distinct steps so as to define at

each step a substantially circular boundary sized to receive a cap of a bottle or other container. As illustrated the device can accommodate four different sizes of cap, though it is of course possible to mould the device with more or less steps.

The number of steps is determined by the number of different caps for which the device is intended, but is also a function of the length of each step and the number of ribs necessary to generate the required opening torque. Furthermore it is not practicable to have too many steps since the device will become unduly large and may foil the body of the container to which the cap is screwed.

Each step tapers inwardly at a shallow angle 18 (best shown in Fig. 4) so as to accommodate caps of nominally the same external diameter but slightly different actual diameters. The arrangement of steps permits a more shallow angle than would be the case if a simple taper from the base to the mouth of the recess were provided for the ribs 17. The taper angle illustrated in Fig. 4 is exaggerated for illustration purposes, and may be rather small. However the angle is in any event determined by the range of diameters within a given nominal cap diameter.

The cap 19 illustrated in Fig. 4 has the usual axially extending ribs 20 with which the ribs 17 engage. As shown in Fig. 2, each rib is angled at its inner edge to present a knife edge 21 which is better able to engage the edge of the cap in the cap removal (anti-

c_-ckwise) direction. (Fig. 2 is a view of the underside).

The knife edge 21 has a relatively shallow angle since it is preferable not to reduce the rigidity of each rib more than necessary. The torque required to undo a cap may be quite high and thus a tight engagement of the ribs 17 and 20 which increases as the opening torque is applied is preferred.

The device has eight exterior finger receiving recesses as illustrated and is thus likely to be adaptable to an aged or infirm user whose hands may have become distorted through arthritis or other illness, or who may be unable to hold small caps with a sufficient degree of grip. The smooth upper surface enables users to comfortably exert sufficient downward pressure on a CRC cap to open a container in cases where finger grip or pressure alone may be insufficient. It is a particular advantage of the device that the user does not need to push and turn a CRC cap using the fingers alone.

The device is of course also suitable for use by persons who would be capable of undoing a conventional CRC but find the operation difficult or awkward. The device may be used with conventional caps.

The recesses between the stiffening ribs may incorporate means to secure the device to a convenient surface where it can readily be found by the user. Such means may comprise for example a sucker or a magnet so that the device can be attached to e.g. the door of a

refrigerator.

A particular advantage of the device is that its function is not apparent from the exterior, and it can be left in a prominent place without causing embarrassment to the user by appearing to be an obvious aid to the disabled or infirm.

Although the device has been described with reference to child resistant containers, it is also useful for turning conventional screwed caps.