ZA200706556B - Electrical plug - Google Patents

Description

17) ‘ ay ‘ } "ELECTRICAL PLUG I | Jil

FIELD OF THE INVENTION "DE

This invention relates to an electrical plug, and more particularly, but not exclusively to a three-pin adaptor for a dual pin plug.

BACKGROUND TO THE INVENTION

There are many methods and mechanisms pertaining to the adaptation or conversion of one type of plug to render it engageable with a different type of socket.

It will be appreciated that most local electrical sockets are of a three-hole configuration. It is however apparent from assessing the market that an increasing number of electrical appliances are manufactured having a dual pin electrical plug. There is therefore a growing demand for the conversion or adaptation of dual pin plugs to make it compatible with the commonly found ~ three-hole sockets.

In one example the user can remove the dual pin plug and replace it with a standard three-pin plug. This is however a tedious exercise and can further result in accidents if attempted by a person unskilled in electrical principles.

It will further be appreciated that many adaptors exist for adapting a dual pin plug to be engageable with a three-hole socket. In existing configurations the contact pins of the dual pin plug are inserted into apertures in an adaptor that has three outwardly extending contact pins. An electrical connection is established between the contact pins of the dual plug and two of the contact pins of the three-pin plug.

Upon insertion of the dual pins into the adaptor, the dual contact pins are brought into contact with some connecting means, which are in turn in electrical contact with the contact pins of the three-pin plug.

A problem associated with this configuration is that the link between the inserted dual pins and the connecting means is often of low integrity. This can be problematic in that the electrical contact is unreliable, and sometimes difficult to establish at all. A further problem lies in the physical connection often not being secure enough to prevent the dual pin plug to be dislocated from the adaptor when subjected to an external disturbance.

It will however be appreciated that there are some designs aimed at preventing © 10 the aforementioned problems. The connecting means are often designed to be somewhat resilient in order to establish a proper connection with the inserted pins. In these designs the receiving means are displaced against its resilience when engaged by the contact pins of the dual plug. A problem associated herewith is that the resilience is entirely due to the elasticity of the receiving means, and there are therefore no external forces enhancing the resilience of the configuration. Continuous use will thus render the functioning of the connecting means sub-optimal, as the connecting means will lose some of its resilience in time.

A further problem associated with existing configurations is that the connecting means are not integral to the contact pins of the adaptor plug, thus necessitating the need for an additional link between the connecting means and the contact pins. It is foreseeable that the additional link can exacerbate the connection problems as already described.

Yet another shortcoming associated with available technology is that adaptors generally cannot be used as ordinary plugs. The adaptors do not allow for the direct connection of an electrical cable and can only accept a second plug. This has the negative implication of limiting a single plug to be either used as an adaptor or as an ordinary plug.

OBJECT OF THE INVENTION

It is an object of this invention to provide an electrical plug which will at least partially alleviate some of the abovementioned problems. s ,

SUMMARY OF THE INVENTION

According to the invention there is provided an electrical plug comprising a casing having a plurality of contact pins extending from the casing, at least two of the contact pins having apertures for receiving contact members of a second electrical plug.

There is also provided for the electrical plug to include biasing means to force the contact pins into electrical contact with the contact members when the contact members are engaged in the apertures.

The biasing means may be a torsion spring, and may be positioned for the simultaneous biasing of two contact pins in opposite directions.

The biasing means may be a curved resiliently plastic strip.

Further features of the electrical plug provide for the contact pins to be L- shaped.

A further feature of the invention provides for the contact pins to have receiving means for receiving an electrical cable.

Further features of the invention provide for the receiving means to include a screw threaded hole and locking screw for securing a bared core of an electrical cable to the contact pin.

There is also provided for the casing to have holes which are aligned with the apertures in the contact pins to receive the contact members therethrough.

Co PEE } A yet further feature of the electrical plug provides for the casing to have holes, which are aligned with the apertures in the contact pins to receive the contact members therethrough.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described by way of example only and with reference to the following drawings in which:

Figure 1 is a perspective view of a contact pin;

Figure 2 is a perspective view of the electrical plug with the cover removed;

Figure 3 is a perspective view showing the engagement of a second plug with the electrical plug; and

Figure 4 is a top view of the electrical plug with the cover removed.

DETAIL DESCRIPTION OF THE DRAWINGS _

With reference to the drawings, in which like numerals indicate like features, an electrical plug is generally indicated by reference numeral 10.

An electrical plug (10) is shown in the figures and includes a casing (12), from which a plurality of contact pins (16) extend. At least two of the contact pins (16) have apertures (18) for receiving contact members (32) of a second plug (30).

Figure 1 shows a contact pin (16) having an elongate section (17) terminating in an elbow section (19), thus rendering the contact pin (16) generally L-shaped.

The elbow section (19) of the contact pin (16) contains an aperture (18) for receiving the contact member (32) of a second plug (32). The elbow section (19) further has cable conductive core receiving means or a core connection aperture (20) being linked to a screw-threaded hole (21) that can accept a locking screw (22). In use the core of an electrical cable (not shown) will be inserted into the connection aperture (20) and subsequently secured by fastening the locking screw (22).

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Figure 2 shows the electric plug (10) with the cover (11) removed. The electrical plug (10) has a casing (12) for supporting the contact pins (16), and being engageable with a complementary adapted cover (11). The cover (11) includes holes (15) being aligned with the apertures (18) in the contact pins (16). The casing (12) and cover (11) further have apertures (14) that, when engaged, coincide to define a cable opening for receiving an electrical cable (40).

The contact pins (16) can rotate about the longitudinal axis of the elongate section (17) of the contact pin (16). The electrical plug (10) includes biasing means (21) in the form of a resiliently curved plastic strip. The biasing means (24) is positioned to bias the two elbow sections (19) of the contact pins (16) in opposite directions.

An electrical cable (40) penetrates the electrical plug (10) through the cable opening (14). The cores (41) of the cable (40) are connected to the contact pins (16) by insertion thereof into the core connection apertures (20), and subsequent fastening of the locking screws (22).

Figure 3 shows the engagement between the electrical plug (10) and a second plug (30). The contact members (32) of the second plug (30) engages the electrical plug (10) via holes (15) provided in the cover (11) for that purpose.

The contact pins (16) of the electrical plug (10) are further suitably dimensioned to engage an electrical socket (not shown).

Figure 4 shows the electrical plug (10) with the contact pins (16) being biased by the biasing means (24) in opposite directions (23).

In use the contact members (32) of the second plug (30) is pushed through the holes (15) in the cover (11), and subsequently into the apertures (18) in the contact pins (16). The distance between the contact members (32) is shorter than the distance between the apertures (18) when the contact members (32) and apertures (18) are not engaged. Upon insertion of the contact members

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. (32), the contact pins (16) are therefore forced towards each other against the bias, thus ensuring proper electrical connection between the contact members (32) and the contact pins (16).

It is envisaged that the invention as described above will solve the problems associated with known technology.

The above is only one embodiment of the invention, and it will be envisaged that many variations in detail are possible without departing from the basic scope of the invention. For instance, the biasing means may be a helical spring, and the cable receiving means may be of a different configuration.

Claims (10)

} CLAIMS ek

1. An electrical plug comprising a casing having a plurality of contact pins extending from the casing, at least two of the contact pins having apertures for receiving contact members of a second electrical plug.

2. The electrical plug as claimed in claim 1 in which a biasing means forces the contact pins into electrical contact with the contact members when the contact members are engaged in the apertures.

3. An electrical plug as claimed in claim 2 in which the basing means is a torsion spring, positioned for the simultaneous biasing of two contact pins in opposite directions.

4. An electrical plug as claimed in claim 2 or 3 in which the biasing means is a curved resilient plastic strip.

5. The electrical plug as claimed in any one of the preceding claims in which the contact pins are L-shaped.

6. The electrical plug as claimed in any one of the preceding claims in which the contact pins have receiving means for receiving an electrical cable.

7. The electrical plug as claimed in claim 6 in which the receiving means includes a conductive core aperture for receiving a bared conductive core of an electrical cable.

8. The electrical plug as claimed in claim 6 or 7 in which the receiving means includes a screw threaded hole and locking screw for securing a bared core of an electrical cable to the contact pin.

9. The electrical plug as claimed in any one of the preceding claims in which the casing has holes which are aligned with the apertures in the contact pins to receive the contact members therethrough.

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10. An electrical plug substantially as herein described with reference to and as illustrated in the accompanying drawings. Dated this A day of Aus awd. Patent Attorné Agent for the Applicant