GB2310767A - Drive-off assembly for a housing with sliding lid - Google Patents

Abstract

A housing, for example the housing of a domestic three pin electrical plug, having a base (1) and a lid (2) slidably engagable with the base comprises a drive-off assembly for moving the lid relative to the base between an open and closed position. The drive-off assembly comprises a complementary detent (11,12) and recess (13,14) between the lid and the base for retaining the lid and base in the closed condition, and a rotatable release button (5) which on rotation urges the detent and the recess apart to allow the lid and the base to be slid apart. The release button is provided with a camming projection (8) which additionally urges the lid towards its open position when the button rotates.

Description

DRIVE-OFF ASSEMBLY FOR HOUSING The present invention relates to a drive-off assembly for a housing. It relates particularly to a housing for an electrical connector such as a domestic three-pin plug and particularly of a type comprising a base and a lid therefore, the lid being slidable between an open and a closed position relative to the base.

Plugs of the foregoing type have been known particularly from EP-A-0073,784. This describes inter alia a housing for a domestic three-pin plug of a type generally used in English speaking countries. This comprises in addition to the usual three electrical connectors, a lid slidably interengagable with a housing base which is lockable into its engaged (closed) condition and manually releasable therefrom by suitably applied manual pressure.

Housings of this type work satisfactorily, but are not considered to be absolutely satisfactory due to difficulties of manufacture and because the closures are not particularly childproof and it is difficult to incorporate a tamper evident means to indicate first use. Accordingly the applicants recently placed on the market a housing for an electrical connector particularly for a three-pin plug, said housing comprising a base and a lid slidably interengaged and movable between an open and a closed position, a complementary detent and recess formed between said lid and said base to retain them in the closed position, and a rotatable release button adapted on rotation to urge the detent and the recess apart to allow the lid and the base to be slid apart.

This arrangement too while an improvement on the earlier disclosure has a significant drawback. This is that in order to rotate the release button against the resilience of the lid to disengage the detent and the recess, it is necessary to use a screwdriver blade, coin, penknife or similar. With the release button in its opened position, the lid and the base still remain in the closed portion until physically forced apart. Because the rotation of the release button has loaded the side of the lid relative to the base, friction is increased such that manually separating the lid from the base can be difficult to achieve particularly for the infirm.

Accordingly, what is required is means for driving the base towards its open position relative to the lid by creating not only a lateral deformation of the skirt of the lid but also simultaneously applying thereto a driving force to drive the lid and the base apart. By means of such an arrangement, it is relatively easy then to insert fingers into the well of the base while gripping the lid with the other hand so that the other two elements may be readily separated.

It is also desirable that the release button should on separation adopt an open position from which it can only be dislodged to the closed position in normal usage by reengagement of the lid with the base such that the same are driven into their closed position. It is thus only necessary to rotate the release button during the opening procedure.

The present invention is therefore characterized in that the release button comprises a camming projection which additionally urges the lid to move towards the open position on rotation of the said button.

Preferably, the housing is for an electrical plug particularly in an electrical plug of a three-pin variety. The camming projection may comprise at least two ratchet members and the recess may be provided with a at least one pawl which acts to drive the lid and the base apart on rotation of the release button.

Preferably, the release button comprises a tamper evident projection adapted to interf it in a corresponding tamper evident projection recess in the base such that on first use after initial assembly, the projection becomes detached and hence indicates first use.

In a preferred form of the invention, the lid is formed with a resilient skirt comprising the detent and the base comprises a corresponding recess, whereby the button acts on rotation to deform the resilient skirt to allow the release of the detent. The button may be formed with at least one transverse stop in addition to any driving slot in order to increase resilience and so allow ready penetration and retention in a release button housing disposed in the base.

In a particularly preferred form of the invention, the release button is resiliently biased to an at rest position in the open position of the lid and the base whereby the sliding of the lid and the base together towards the closed position restores the release button to its at rest closed position as the recess and detent interengage.

By means of this arrangement, it is possible for the lid of a three-pin plug for example to be readily opened by householders, etc without difficulty.

The invention will now be described, by way of illustration only with reference to the accompanying drawings wherein: Figure 1 shows a plan view from beneath of a three-pin domestic plug base in accordance with the invention; Figure 2 shows an end view of a slidable lid for use with the three-pin domestic plug of Figure 1; Figure 2A shows a plan view of an assembled three-pin plug of Figures 1 and 2 from beneath; Figure 3 shows an enlarged view from above of the release button bore of Figure 2A with parts of the lid broken away; Figure 4A shows a side elevation of a release button in a first position; and Figure 4B shows a plan view of the release button of Figure 4A from below.

With references to Figure 1 to 2A, there is provided a domestic electrical plug base 1 for cooperation with a lid slidably interengageable therewith shown in elevation in Figure 2. The lid 2 is moulded from a resilient plastics material such as a copolymer. The plug base 1 is moulded from a similar or different plastics material such as a urea based copolymer which is both non-electrically conducting and relatively hard.

The base 1 is formed with a base surface 3 through which are disposed a plurality of connector pins 4 in their usual configuration. The longitudinal edges of the plug base 1 are formed with internal grooves 9 for cooperation, as will be described later, with the lid of Figure 2.

Disposed in the upper right quartile of Figure 1 and immediately adjacent neutral connector 4 is a release button 5. The release button 5 as will be described later is disposed in a cylindrical bore 6 in which it is retained. The release button 5 is provided with a truncated face 5A. The release button 5 is provided at 12 o'clock seen in Figure 1 with a tamper-evident plug 7, and with a drive slot 23.

The groove 9 adjacent the release button 5 is provided superior to the release button 5 as shown in Figure 1 with a secondary recess 14 and is provided with a primary recess 13 adjacent the truncated face 5A of the release button 5.

The release button 5 is also provided with a camming projection 8 for purposes which will be elucidated later.

In Figure 2 is shown in end elevation the slidable lid for cooperation with the plug base 1. The lid 2 is comprised of a crown 15 and a downwardly depending resilient skirt 16 terminating at its lower edge in an upturned peripheral rib 17. As is shown to the left hand side of Figure 2, a primary detent 11 and a second detent 11 as shown in Figure 2A are provided.

With reference particularly to Figure 2A, it will be seen that the lid 2 and the plug base 1 are interengaged in Figure 2 such that the release button 5 is shown in its at rest position with the tamper evident projection 7 in position in a corresponding tamper evident projection recess 7A.

The arrangement of the plug is also shown in Figure 3 which is an enlarged view from above of a release button bore 6 of Figure 2A with a portion of the lid 3 broken away. As can be seen from Figure 3, the cylindrical bore 6 is provided with a cylindrical recess 6A to accommodate and retain the release buttons. It will also be observed that the tamper evident plug recess 7A is positioned at about 12 o'clock. Also clearly shown in Figure 3 is the primary detent 11 and the second detent 12.

Referring now to Figures 4A and 4B, there is shown a side elevational view of the release button whereas Figure 4B shows the same from below.

The release button 5 comprises a cylindrical body 22 provided with an axially disposed slot 23 for engagement with a screw driver blade, coin, pen knife, etc. The body 22 is provided at the left hand side with a tamper evident projection adapted to fracture on first rotation.

Superior to the body 22 is provided, a resilient clip 19 comprising, in the present instance four clip elements which together form a generally cylindrical clip 19 provided with cross slots 20 in order to provide the necessary degree of resilience such that the clip 19 can pass through the bore 6 such that the flange 21 locates in the inner surface of the plug base 1. The camming projection 8 is to be seen on the right-hand lower edge of Figure 4A.

Figure 4B provides a section on X-X of Figure 4A clearly showing the camming projection 8, the tamper evident plug 7, the rotatable body 22 and the drive slot 23.

In use, the resilient clip 19 of the release button 5 is pressed through to the underside of the plug base 1 so as to inters it with the cylindrical bore 6. It will be observed that the tamper evident projection 7 is interfitted with the tamper evident projection recess 7A. In this position, the lid 2 may be slid interengagement with the plug base 1 by interengaging the upturn peripheral ridge 17 with the groves 9 and applying reciprocal pressure.

With the lid and the base in full interengagement if the tamper evident projection 7 has not been broken it is readily apparent to the manufacturer that no attempt has been made to open the plug. This is important where plugs are prewired on initial assembly.

When it is desired to change a fuse or to rewire the plug, it is only necessary to use a screw driver blade or coin in the slot 23 and rotate the same by for example 600 to 900 in this case in the anticlockwise position as shown in Figure 2A. The effect of this is initially to destroy the lug 7 to indicate first use and at the same time, the camming projection 8 contacts the primary detent 11 and forces the resilient skirt 16 immediately adjacent to deform. This deformation, due to the inherent strength of the skirt 16 also causes deformation of the secondary detent relative to the secondary recess such that the lid and the plug base may now be slid apart.

However, at the same time, the camming projection 8 catches in the bottom edge of the detent 11 and urges the lid to slide forwardly relative to the plug base 1 thereby opening the plug housing by causing the lid to move relatively forwardly of the plug base 1. Further rotation to its maximum 900 then urges the lid to move relatively further. In this particular embodiment, a stop member (not shown) is positioned adjacent the cylindrical port 6 to prevent movement further than 90 .

In this position, the camming projection 8 protrudes beyond the detent. It follows that when the lid is slid back into position to close the plug housing, the upturned peripheral rib on the lid 2 will come into contact with the camming projection 8 and cause the same to move to its closed position as the lid is slid into the closed position.

It will be appreciated that the single camming projection may be replaced by one or more ratchet and pawl arrangement so that the rotation of the release button may be effected through 180 or 3600 thereby driving off the lid from the base in a more positive manner. While such arrangements are satisfactory, they have not been found necessary in this particularly embodiment. The invention relates therefore to a housing comprising a base member and a lid slidable therewith provided with a drive-off assembly as herein set forth. The invention also provides an electrical connector comprising such a drive-off assembly.

Claims (9)

CLAIMS:

1. A housing comprising a base and a lid slidably engaged therewith and movable between an open and a closed position, a complementary detent and recess formed between said lid and said base to retain them in the closed position, and a rotatable release button adapted on rotation to urge the detent and the recess part to allow the lid and the lid and the base to be slid apart, characterized in that the button comprises a camming projection which additionally urges the lid to move toward the open position on rotation of the button.

2. The housing according to claim 1 in the form of an electrical connector.

3. A housing according to either of claims 1 or 2 wherein the camming projection is in the form of a ratchet and the recess comprises a pawl thereby to assist opening upon rotation of the release button.

4. A housing according to claim 3 wherein the camming projection comprises at least two ratchet members.

5. A housing according to any preceding claims further comprising a tamper evident projection disposed in a tamper evident projection recess and adapted to fracture on first use of the release button.

6. A housing according to any preceding claim wherein the lid is formed with a resilient skirt and comprises a detent and wherein the base comprises a recess and wherein the release button acts upon rotation to form the resilient skirt to allow the release of the detent.

7. A housing according to any preceding claim wherein the release button is formed with at least one transverse slot to increase resilience.

8. A housing according to any preceding claim wherein the release button is retained in an at rest position in the open position of the lid and the base, wherein sliding the lid and the base together towards the closed position restores the release button to its at-rest closed position as the recess and detent interengage.

9. A housing substantially as hereinbefore set forth with reference to, and/or as illustrated in, Figures 1 to 4A of the accompanying drawings.