The present invention relates to a two-part bulb holder which prevents or reduces the chance of electrocution from an exposed light socket.

An electrical hazard results when a bulb is removed from its socket. Children in particular are at risk from floor or desk mounted lighting units, such as angle-poise lamps. With a light bulb removed from a bayonet fitting or an Edison screw-fitting, small fingers of an unattended child can easily be placed in the open socket. If the conductors are live, electrocution may occur.

The present invention seeks to provide a solution to this problem. According to a first aspect of the present invention, there is provided a bulb holder comprising a mounting part and a bulb-engagement part which is releasably engagable with the mounting part, the mounting part including an enclosure, two electricity- supply conductors within the enclosure, and two spaced access openings in a wall of the enclosure for respectively accessing the two electricity-supply conductors, the bulb- engagement part including a shroud, a bulb connector for releasably engaging a bulb and which is recessed within the shroud, and a spring-biased pin carrier carrying two elongate pin conductors, the pin conductors being movable between extended positions in which the pin conductors project from access openings in a wall of the shroud and retracted positions in which the pin conductors are recessed within the shroud, the pin conductors being extendable on engagement of a bulb with the bulb connector, and being receivable on extension in the respective access openings of the enclosure to affect electrical communication with the respective electricity-supply conductors, whereby the bulb is non-removable from the bulb-engagement part whilst the bulb- engagement part is engaged with the mounting part. Preferable and/or optional features of the first aspect of the invention are set forth in claims 2 to 13, inclusive.

A bulb holder in accordance with the first aspect of the invention, in combination with a bulb, the bulb being lockable to the bulb-engagement part by the spring-biased pin carrier when the pin conductors are received in the mounting part against the electricity- supply conductors.

The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which : Figure 1 shows a perspective view of a first embodiment of a bulb holder, separated and with no bulb attached, and in accordance with the invention;

Figure 2 shows a bulb-engagement part of the bulb holder with a bulb attached;

Figures 3a to 3c show a partial longitudinal cross-sectional view of the in use bulb holder; Figure 4 shows a longitudinal cross-sectional view of a second embodiment of a bulb holder, in accordance with the invention;

Figures 5 and 6 show exploded perspective views of the second embodiment of the bulb holder; and

Figures 7 and 8 show longitudinal cross-sectional views of a third embodiment of a bulb holder, in accordance with the invention.

Referring firstly to Figures 1 to 3c of the drawings, there is shown a first embodiment of a two-part separable safety bulb holder 10 which comprises a mounting part 12 and a bulb-engagement part 14. The mounting part 12 receives a mains power inlet, either transformed or untransformed, typically via a mains power cable 16, and provides a socket for holding the bulb- engagement part 14. In particular, the mounting part 12 includes a conductor mounting block 18, at least two rigid electricity-supply conductor elements 20, typically in the form of spaced apart terminal pins or plates for Live and Neutral feeds, and a rigid, in this case moulded plastics, hollow enclosure 22 which surrounds the mounting block 18 and the electricity-supply conductor elements 20. The enclosure 22 is dimensioned so that the electricity-supply conductor elements 20 are internally spaced away from a front wall 24 thereof. Two apertures in the form of spaced access openings 26 are formed in the front wall 24 to provide restricted access to the electricity-supply conductor elements 20 within the enclosure 22. The spaced access openings 26 are dimensioned to prevent finger insertion. In this case, the spaced access openings 26 are also configured to provide keyway slots 28, whereby the spaced access openings 26 provide elongate channels having a wide end 30 and a narrow end 32, as best seen in Figure 1.

A collar 34 is also provided on the enclosure 22. The collar 34 in this case is a continuous ring which projects above a plane of the front wall 24. Preferably, the collar 34 is screw-threadingly engaged with the enclosure 22, but it may be a push- or snap- fit. It may also be integrally formed as one-piece with the enclosure 22. The collar 34 not only provides conductor shielding as described hereinafter, but also provides lateral stability at the interface of the connection between the mounting part 12 and the bulb- engagement part 14.

The bulb-engagement part 14 comprises a bulb connector 36, a pin carrier 38, and a shroud 40 which surrounds a perimeter of the bulb connector 36. The bulb connector 36, preferably being moulded plastics, forms a socket for mounting a bulb 42. In the case of a bayonet or BC fitting, a perimeter wall 44 of the bulb connector 36 includes opposing L-slots 46 for receiving the radially outwardly projecting pins 48 on the bulb base 50. In the case of an Edison screw or SC fitting, the perimeter wall of the bulb connector 36 includes a suitable screw-thread. The shroud 40 provides a planar or substantially planar base wall 52 for abutment with the front wall 24 of the enclosure 22, and a uniformly continuous side wall 54 which extends contiguously from a perimeter edge of the base wall 52 so as to surround the bulb connector 36 in a recessed manner. Preferably, the shroud 40 includes a flared free distal end portion 56 to aid insertion of the bulb base 50. A uniformly continuous stepped- shoulder 58 is also preferably provided at the intersection between the base wall 52 and the side wall 54 of the shroud 40. The stepped-shoulder 58 is adapted to receive the collar 34 of the mounting part 12 as a close fit to stably support the connection interface of the two parts 12, 14. The pin carrier 38 includes an electrically- insulated rigid mounting plate 60, at least one spring 62, in this case being a coil spring, and two spaced elongate pin conductors 64. The mounting plate 60 is received for slidable movement within the bulb connector 36. The mounting plate 60 is oriented so as to be movable in a plane which is parallel or substantially parallel with the base wall 52 of the shroud 40.

The spring 62 is preferably provided centrally of the mounting plate 60 so as to be interposed between the mounting plate 60 and an inner surface of the base wall 52. In this way, the mounting plate 60 is spring-biased in the direction of the distal end 66 of the shroud 40 and away from the base wall 52. The elongate pin conductors 64 are carried by the mounting plate 60 in spaced relationship. The pin conductors 64 extend through the mounting plate 60, thereby providing a minor contact portion 68 for the bulb terminals 70 at a distal-end side of the mounting plate 60, and a major projectable portion 72 at the base-wall side of the mounting plate 60. The minor contact portions 68 of the pin conductors 64 are located on the mounting plate 60 so as to be electrically engagable with the terminals 70 of the bulb 42, once the bulb 42 is engaged with the bulb connector 36.

The pin conductors 64 are preferably rectilinear, and two further apertures in the form of spaced-apart access openings 74 are provided in the base wall 52 so as to be aligned with ends of the pin conductors 64. This enables the major projectable portions 72 of the pin conductors 64 to extend therefrom when the mounting plate 60 is pushed down. The spacing of the pin conductors 64 is such as to be alignable with the spaced access openings 26 in the front wall 24 of the enclosure 22 of the mounting part 12.

A longitudinal extent of each pin conductor 64 is such that, when in its extended condition, reliable and positive electrical contact is made with the respective electricity- supply conductor elements 20 within the enclosure 22 of the mounting part 12.

An end of each pin conductor 64 at the major projectable portion 72 includes a contact head 76 integrally formed as one-piece with the shaft 78 of the pin conductor 64. The contact head 76 is dimensioned to be able to pass through its respective access opening 74 in the base wall 52 and the access opening 26 in the front wall 24 of the enclosure 22 as a close fit, and to make electrical contact with its respective electricity-supply conductor element 20.

In use, the enclosure 22 and/or the conductor mounting block 18 of the mounting part 12 is/are provided fixed to a ceiling rose, freely depending from an end of an electrical cable 16, or supported by a lamp base or stand such as an articulated angle-poise arm. The fixed electricity-supply conductor elements 20 are provided in electrical communication with the conductors of the mains power supply, and the collar 34 provides a skirt which extends around the front wall 24.

Without a bulb 42 held by the bulb- engagement part 14, the pin conductors 64 are in their fully unexposed retracted or sheathed condition, and thus the bulb-engagement part 14 cannot be engaged with the mounting part 12. The electricity-supply conductor elements 20 within the enclosure 22 of the mounting part 12 thus remain fully away from any possible contact with inquisitive fingers.

By engaging a bulb 42 with the bulb connector 36, the pin carrier 38 is urged downwards towards the base wall 52, causing the pin conductors 64 to extend through the spaced-apart access openings 74. In this condition, the extended pin conductors 64 can be inserted into the keyway slots 28 in the front wall 24 of the enclosure 22 by aligning the mounting part 12 and the bulb- engagement part 14 such that the stepped shoulder 58 of the mounting part 12 seats on the collar 34. The keyway slots 28 align the heads 76 of the pin conductors 64 with the electricity-supply conductor elements 20. With the heads 76 of the pin conductors 64 inserted through the spaced access openings 26, the bulb-engagement part 14 is twisted thereby rotatably sliding on the collar 34. The twisting results in releasable locked engagement of the pin conductors 64 with the keyway slots 28. The relative angular movement of the bulb-engagement part 14 causes the heads 76 of the pin conductors 64 to electrically engage with the electricity-supply conductor elements 20 within the enclosure 22.

The spring 62 within the bulb-engagement part 14 biases the bulb-engagement part 14 firmly into engagement with the mounting part 12 by drawing the heads 76 of the pin conductors 64 against the underside of the front wall 24 of the enclosure 22 of the mounting part 12. As such, the electricity-supply conductor elements 20 within the enclosure 22 are suitably spaced or sprung themselves to maintain electrical contact despite the biasing of the two parts 12, 14. By way of example, the electricity-supply conductor elements 20 may include ramped portions allowing the heads 76 of the pin conductors 64 to slide up and along the electricity-supply conductor elements 20 as the bulb-engagement part 14 is twisted into its locked condition.

With the mounting part 12 and the bulb-engagement part 14 engaged, the bulb 42 cannot be unintentionally removed, even if the spring-biasing of the pin carrier 38 provides some slack. The bulb 42 can only be removed once the bulb- engagement part 14 is twisted to unlock the heads 76 of the pin conductors 64 from their keyway slots 28. The bulb-engagement part 14 can then be removed from the mounting part 12 with the collar 34 shielding the exposed pin conductors 64 as the heads 76 are lifted clear of the spaced access openings 26. Once clear, the pin conductors 64 become exposed between the collar 34 and the base wall 52 of the shroud 40 of the bulb-engagement part 14. However, in this condition, the electrical connection between the pin conductors 64 and the main electrical connectors is broken, preventing any possibility of an electrical hazard.

In a modification to the first embodiment described above, the spaced access openings in the front wall of the enclosure may include movable covers, preferably being within the enclosure and on or adjacent to the underside of the front wall. The movable covers may be ramped so that, as the heads of the pin conductors are introduced, the movable covers are urged laterally relative to the pin conductors to uncover the access openings.

In an alternative arrangement, the pin carrier may include an elongate urging member, for example, interposed between the pin conductors and also extendible from the base wall of the shroud via a dedicated opening spaced, for example, between the spaced- apart access openings. The urging member is receivable in a further access opening in the front wall of the enclosure. Typically, the urging member would project further than the pin conductors, and would thus engage the movable covers, for example, at the ramped portions, to move the covers as the heads of the pin conductors are being inserted into their respective spaced access openings. In this arrangement, therefore, the movable covers are moved by the urging member before the covers can be engaged by the heads of the pin conductors. The collar mentioned above may also conveniently utilised to attach a lamp shade.

The enclosure of the mounting part may be adapted to be retro-fittable to or around an existing socket, for example, by the provision of an interior or exterior screw-thread at an opening in the end opposite the front wall. Referring to Figures 4 to 6, a second embodiment of a two-part separable safety bulb holder is shown. Like references refer to parts which are similar to those of the preceding embodiment, and therefore further detailed description is omitted.

The bulb holder 10, as before, comprises a mounting part 12 and a bulb- engagement part 14 which is separable from the mounting part 12. The two-spaced access openings 26, providing the keyway slots 28, are formed in the front wall 24 of a leading part 22a of the enclosure 22, and are closed by a movable, in this case spring-biased rotatable, access cover 25. The leading part 22a of the enclosure 22 is releasably engagable, in this case via mating screw-threads, with a trailing part 22b, although the enclosure 22 may, as in the first embodiment, be integrally formed as one-piece.

The bulb- engagement part 14 comprises the bulb connector 36, pin carrier 38 and shroud 40. However, in this particular case, the pin carrier 36 is integrally formed as one-piece with the shroud 40. The pin carrier 38 may of course be separable of the shroud 40. The pin carrier 38 receives the two elongate pin conductors 64, each of which is received at least in part within coiled spring 62. The springs 62 are urged against the base wall 52 as the bulb is inserted into the bulb connector 36 and the pin conductors 64 are urged to project through the spaced-apart access openings 74 in the base wall 52.

In this embodiment, and not shown in the first embodiment, a coupling element is included on the bulb-engagement part 14 for coupling the bulb- engagement part 14 with the mounting part 16, independently of the pin conductors 64. In this case, the coupling element comprises two diametrically opposed hook-shaped or L-shaped lugs 78 which are integrally formed as one-piece with the base wall 52. Complementarily shaped lug openings 80 are formed in the front wall 24, spaced from the access openings 26.

With the bulb base 50 of the bulb 42 engaged with the bulb connector 36, so that the pin conductors 64 protrude from the base wall 52, the bulb-engagement part 14 can be offered up to the front wall 24 of the mounting part 12, so that the pin conductors 36 enter the access openings 26 and the lugs 78 enter the lug openings 80. The bulb- engagement part 14 is then axially rotated to engage the pin conductors 36 in the access openings 26 and the lugs 78 in the lug openings 80, thereby preventing or limiting unintentional axial separation of the two parts 12 and 14. With the bulb-engagement part 14 disengaged from the mounting part 12, the access cover 25 is spring biased to a position which closes the access-openings 26.

Referring to Figures 7 and 8, a third embodiment of a two-part separable safety bulb holder is shown. Like references again refer to parts which are similar to those of the preceding embodiments, and therefore further detailed description is omitted. The bulb holder 10, as before, comprises a mounting part 12 and a bulb- engagement part 14 which is separable from the mounting part 12.

This embodiment is adapted to receive an Edison screw-threaded bulb base 50a. To this end, the bulb connector 36a is engaged within the shroud 40 to be freely rotatably and to have limited axial movement in an internal channel 82. An interior shoulder 84 includes castellations 86 therearound, and complementarily shaped teeth 88 are formed on the axially lower surface of the bulb connector 36a.

The screw-threaded bulb base 50a is engaged with the screw-threaded bulb connector 36a by pushing the bulb downwards into the bulb connector 36a whilst turning. This downwards pressure causes the castellations 86 to engage with the teeth 88, thereby angularly locking the bulb connector 36a relative to the shroud 40.

As the bulb base 50a is screwed home onto the pin carrier 38, the pin conductors 64 are forced to protrude from the base wall 52, as described with reference to the earlier embodiments. Contacts 90, preferably being sprung, are provide for providing electrical communication between the screw-threaded bulb base 50a and the respective pin conductors 64.

As in the second embodiment, the coupling element is provided. The coupling element preferably includes the lugs 78 and the lug openings 80.

Although the coupling element described above may be or include two lugs with respective lug openings, only one lug and corresponding lug opening may be provided, or more than two lugs with corresponding lug openings may be provided.

Furthermore, the lugs may be provided on one or both of the mounting part and the bulb-engagement part, and likewise the lug openings may be provided on one or both of the mounting part and the bulb-engagement part.

It is thus possible to provide a two-part safety bulb holder which prevents or limits the risk of electrocution by the insertion of a foreign object, when the bulb is removed. The bulb cannot be removed without first disengaging the bulb-engagement part. Preferably, with the bulb-engagement part removed, the access openings to the electrical conductors in the mounting part are automatically covered or blocked. It is also possible to provide a two-art safety bulb holder which locks the bulb to one said part, whilst both said parts are interconnected, thereby preventing removal of only the bulb and thus exposure of potentially live contacts. The embodiments described above are provided by way of examples only, and further modifications will be apparent to persons skilled in the field without departing from the scope of the invention as defined by the appended claims.