Background to the invention Electric extension cords are commonly used in the transmission of power from a source to an electric device, both in domestic and industrial environments. For example, in the household, such extension cords are widely used in the operation of power tools, vacuum cleaners, mobile lighting appliances, and other portable electric equipment. It is not uncommon for a number of such extension cords to be interconnected to enable the use of a device"at a substantial distance from a power point, and such an arrangement may be frequently employed in operating an electric lawn mower or hedge trimmer, or in a building site environment, for example.

Typically, an electric extension cord comprises a male and a female plug, interconnected by a length of flexible mains power cable. The male plug is connected to a mains power outlet, and the male plug of the electric appliance (or a further extension cord) can then be connected to the female plug of the extension cord. This connection between the male and female plugs is of concern, as it tends to be subject to tension as the user moves around the work area, and such tension can often lead to separation or disconnection of the conducting elements in the plugs. This can be a considerable inconvenience, necessitating the user to manually reconnect the plugs, which may involve lengthy downtime on the part of the operator, who may, for example, need to come down from a ladder or leave one work area for

another. Perhaps more significantly, the problem raises serious safety issues, as partial separation can result in the exposure of the live plug tines. This can be especially dangerous when an extension cord is used on building and construction sites where the environment can be harsh and cords can readily become separated. However, problems also exist when an extension cord is used in wet environments, such as on damp grass, in wet weather, in kitchens and bathroom locations, or in situations where small children may be present.

There have been attempts in the past to address this problem, including the use of protection devices to shroud the plug interconnection. Some of these devices have been effective in certain circumstances, but none has provided an adequate solution to the problem in a form suitable for use with the wide variety of plug designs currently available.

Summary of the invention It is an object of the present invention to at least partly address the inconveniences of the prior art, and to this end there is provided an electric cord connection housing unit for secure encapsulation of a coupled plug pair, each plug connecting to a respective electric cord, the housing unit comprising a first and second housing portions and having a latching means for securing the housing portions to one another when the housing portions are disposed in a closed configuration, the housing portions having respective complementary mating edges, the edge of at least one of said housing portions has at least two recesses adapted to provide, when the housing portions are disposed in said closed configuration, at least two ports to receive respective ones of said electric cords, wherein a first housing portion is provided with a continuous elongated first seal element extending around the mating edge of the first housing portion and the second housing portion is provided

with a second seal element in at least the region of said recesses, the first and second seal elements being disposed such that, when in use in the closed configuration around a coupled plug pair, said seal elements serve to substantially seal the mating edges against one another and the ports against the electric cords, and wherein at least one of said housing portions is lined with a compressible foam layer to envelope and secure the coupled plug pair when the unit is in said closed configuration.

Preferably the housing is adapted to accommodate a variety of plug shapes and sizes.

Preferably said second seal element is a continuous elongated seal element extending around the mating edge of the second housing portion.

Preferably both housing portions are lined with a compressible foam layer.

Preferably each of said housing portions has recesses which define said ports.

In a preferred form, in the region of said arcuate recesses, said at least one seal element is mounted to a flexible support to thereby accommodate a variety of cord diameters. Additionally or alternatively, an elongate lip may be provided projecting from or adjacent to the edge of one said housing portions to overlap the edge of the other said portion when in the closed configuration.

Each said housing portion may have a generally semi-cylindrical mid part, tapering to a narrowed semi- cylindrical end part toward the position of said cord ports.

Preferably, said housing portions are hingedly interconnected by means of at least one integral hinge element. This may be provided at one side of the respective housing portions, the latching means provided at the other side.

The housing unit may include a keeper leash

configured for attachment to an electric cord to retain the unit when not in use.

In a preferred form, at least one cord grip means is provided on each said housing portion at or adjacent the position of the cord ports, arranged to grip the outer insulation layer of the cord. This cord grip means preferably features a plurality of spaced arcuate elements, and each element may comprise an arcuate array of teeth, or an arcuate flange, projecting inwardly when the housing is in its closed configuration. Preferably, the arcuate elements are inclined towards the cord direction in such a way as to grip the cord if tension is applied. The arcuate elements may be integrally formed with the housing portions.

In a preferred form, each housing portion is provided with a semicircular flexible elastic membrane at or adjacent the position of each cord port.

Brief description of the drawings The invention will now be described in more detail by way of a non-limiting exemplification and with reference to the accompanying drawings, in which: Figure 1 shows in isometric view an electric cord connection housing unit in accordance with the present invention, the unit in its open configuration; Figure 2 shows the unit of Fig. 1 in side elevation in its closed configuration ; Figure 3 shows a transverse cross-section of the unit at III-III ; Figure 4 shows a longitudinal cross-section of one end of the unit ; Figure 5 shows a transverse cross-section of the unit at V-V ; and Figure 6 shows a details of a transverse cross- section of the unit at VI-VI.

Detailed description of the drawings

A conventional electrical extension cord connection comprises flexible electric conductor cords 20,20', respectively terminating in a female and a male plug 21,22. The plug configuration can take a variety of different forms and sizes, as standard electric plugs vary from country to country, whilst even within a single jurisdiction a range of different designs are commonly available. The conventional electrical extension cord connection is typically between the male plug of an electric device and the female plug of an extension cord.

As described above, when connected and in use under tension or other stress, the coupling between plugs 21 and 22 can be unreliable and lead to a substantial safety risk.

Cord connection housing unit 10 generally comprises a smooth, contoured one-piece plastic housing designed to surround interconnected plugs 21,22 to maintain the interconnection and provide protection to the coupled assembly, as will be explained in more detail below. The smooth contoured shaping of unit 10 enables the device when clamped in place to be dragged around on the extension cord without catching or snagging on obstructions.

Two housing portions 11 and 12 make up unit 10, interlinked by means of integral seam-type hinge elements 13 (Fig. 2). Each housing portion 11,12 has a generally longitudinal dished form, with a wide main portion of generally hemi-cylindrical section, tapering towards two end parts also of generally hemi-cylindrical shaping, as Figs. 1 and 2 illustrate. In its closed configuration, then, unit 10 forms an axially-bisected generally cylindrically shaped plastic capsule, tapering towards the ends. Unit 10 may be formed from an injection-moulded plastic material, preferably of somewhat flexible and resilient properties, such as polypropylene, polyethylene, or a mixture of the two.

Housing portions 11 and 12 are provided with

substantially planar peripheral mating faces as shown which come together to close the unit when in use, and portions 11,12 also feature respectively complementary integrally moulded latch elements 14,14'each located on the side opposed to hinge elements 13, to secure together the two portions of unit 10 when it is closed over interconnected plugs 21,22. Each end part of each housing portion 11,12 terminates in a semicircular opening as shown, to provide circular ports at the longitudinal extremities of the housing in its closed configuration, through which ports cords 20,20'pass. A flexible keeper leash 15, which may also be integrally moulded with housing unit 10, extends from the unit to enable attachment to extension cord 20'near the female plug end of that cord, so that the unit is readily available for use whenever the extension cord is utilised.

It is important that unit 10 is able to securely and resiliently support and enclose the interconnected plugs, and to this end each housing portion 11,12 is lined with a bed of compressible foam material 16, such as waterproof silicone foam, bonded to the interior of the respective housing portion and extending to the tapered sections of the portions, but not extending as far as the two ends of the housing unit. Foam beds 16 serve two functions. Their compressible nature affords the accommodation of a wide variety of different plug shapes and sizes, resiliently and robustly locking around interconnected plugs 21,22 to hold them together against separation when unit 10 is closed. Additionally, the foam forms an internal moisture seal around the interconnected plugs to minimise moisture ingress when used in damp environments, and so avoid or at least reduce the safety risks.

The foam beds 16 are formed so as to be harder near the ends of the housing portion 11,12 then at the midpoints of the housing portions 11,12. The harder foam at the end is more resilient than the softer foam in the

middle and tends to force the male and female plugs 21,22 together and resist separation of the electrical coupling.

A primary moisture seal is provided by an O-ring 17 of soft, compressible silicone plastic or rubber, running around the entire internal periphery of the mating faces of the two housing portions 11 and 12. As Fig. 6 schematically depicts, O-ring 17 is bonded within a groove formed in the mating faces of the housing portions, whilst around the semi-circular ends of housing portions 11 and 12 it is bonded to arcuate flexible mounting elements 18.

In this way, when the housing is closed, the opposed portions of O-ring 17 seal against one another around the planar mating faces to provide a moisture seal, whilst each arcuate end section of O-ring 17 provides half of an annular moisture seal around the outer insulation of cords 20,20', the flexible mounting elements 18 allowing the accommodation of electrical cords of varying diameters without compromising the integrity of the seal. As Fig. 5 illustrates, this arrangement provides waterproofing capability at all critical points (W) where moisture may otherwise find an ingress route.

The unit also includes a longitudinal lip is projecting from the outer edge of the planar mating face of one of the housing portions 12 to overlap the other portions 11 when the unit is closed, to provide a dirt seal along the length of the housing when in use.

Additionally, both ends of each housing portion 11,12 are provided with semi-circular flexible membranes 30 as shown to seal the circular ports at the longitudinal extremities of the housing when in its closed configuration when not in use, so to prevent unwanted ingress of dirt and moisture between uses. In use, membranes 30 are sufficiently flexible to elastically distend around cords 20,20', and so provide a further level of protection against ingress of dirt and moisture.

As Fig. 4 shows, the tapered end parts of the housing portions have a hemi-cylindrical internal shaping,

and are provided with a plurality of longitudinally spaced, opposed arcuate sets of shark-like teeth 31, inwardly angled as shown. These teeth 31 are of flexible plastic and may be integrally formed with the housing, and when unit 10 is closed they serve to engage at their tips the outer insulation of cords 20,20'. If the cords experience tension, due to their inwardly directed form the teeth grip into the cords to hold them in place and help prevent the separation of the electrical coupling.

The sectional view in Fig. 3 illustrates one set of these teeth engaging the outer insulation of cord 20. The copper conductors within cord 20 are depicted by reference 23.

To use, unit 10 is opened by means of latch 14, 14', and the interconnected plugs are approximately centered on the foam bed of one half of the unit. The two cords are respectively routed via the tapering sections through the seal-lined end ports, and the housing is then closed and latched.

The device of the preferred embodiment of the invention, then, provides a convenient, one-piece unit which, in use, encapsulates the interconnected plug assembly in a physically robust manner, providing a high degree of water resistance. This prevents potentially dangerous exposure of live tines, maintains the connected plugs together, and serves to transfer any load on the cords directly to the housing itself, rather than to the plugs. In addition to the safety advantages, the unit provides a time saving capability, by eliminating the need to reconnect accidentally disconnected electrical leads Modifications and improvements to the invention, whether in terms of additional or alternative features, will be readily apparent to those skilled in the art.

For example, although the embodiment described and illustrated features cord ports at its opposed ends, these ports could instead by provided along the longitudinal sides of the housing, O-ring 17 being

configured to seal this form of housing in a similar manner to that described above.

Silicone foam beds 16 are illustrated as having planar surfaces, flush with the planar mating faces of the edge of the housing portions. It will be understood that they may feature shaped recesses or depressions or projections, and/or their surfaces may be recessed within the housing portions. It will also be appreciated that only one half of the housing need be provided with a foam bed 16, although to accommodate the greatest possible range of different plug forms and sizes the maximum flexibility will be provided by lining both of the housing portions 11,12 with foam beds.

Annular sets of teeth 31 may be replaced by one or more flexible annular inwardly directed flanges, to grip the respective cords in a similar manner to that described hereinbefore.

As an alternative to making the portions of the foam beds 16 nearer the ends of the housing portions 11,12 to be harder then at the mid-point, it is possible to provide other biasing means for forcing the plugs together. For example, arms carried by the housing portions which bear on the plugs 11,12, or flanges of similar nature to the card grip means.

Further, while less preferred, it is possible to take advantage of some of the features of embodiments of the present invention without hinging the housing portions to one another. For example, the housing portions could be designed to clip together.

Those skilled in the art will appreciate that the device as described is susceptible to various further changes and modifications without departing from the spirit and scope of the invention.