CIGAR LIGHTER PLUG

Abstract: A plug (1) for use in a cigar lighter socket (25) of a vehicle comprises a plug body (3), a tip contact (5) mounted in the end of the body for engagement with the base contact of the socket (25) and a pair of outwardly sprung radially extending side contacts (9) mounted on the body (3) for engagement with the wall (37) of the socket. A pair of radially extensible engagement means (11) are moveable between a first retracted position and a second position in which they engage the wall (37) of the socket at a position spaced longitudinally of the plug away from the side contacts (9) to prevent pivoting of the plug (1) relative to the socket (25) about the contact points of the side contacts (9) with the wall (37) of the socket (25).

Description: CIGAR LIGHTER PLUG This invention relates to a cigar lighter plug for automotive vehicles. The cigar lighter sockets on vehicles are not only used for cigar lighters but are also used to provide electrical current for all manner of different purposes ranging from charging mobile phones to car vacuum cleaners and tire inflation pumps To provide a connection between the plug and the socket, there is a first connection on the tip of the plug which mates with a contact at the base of the socket and a sideways or radially extending contact with mates with the side surface of the socket. Generally, there are two radially extending contacts which meet on diametrally opposite surfaces of the socket. There is, however, a problem with cigar lighter sockets. They come in a number of different diameters and, as a result, any plug which is to be used with all types of lighter socket has to have its diametrally arranged contacts movable over a relatively large distance to make contact with all the different diameters of lighter socket. This does not cause any real problems until it is desired to mount equipment on the plug, such as a mobile phone receptacle and/or a speaker and an amplifier, At this point the weight of the equipment acts on the plug which then becomes unstable and can move downwardly through an arc about the radially extending contacts. This is disadvantageous in as much as the equipment carried by the plug is no longer properly supported by the plug and, in any event the equipment can wobble. In extreme cases, the plug could be caused to fall out of the socket, not only rendering the equipment inoperative from lack of electrical supply but also possibly causing damage to the equipment itself. Such movement may also be a distraction to the driver. The present invention, therefore seeks to provide a plug which can be used with at least the majority of cigar lighter sockets currently on the market but can be held stable in the socket. According to the invention, there is provided a plug for use with a cigar lighter socket of a vehicle comprising a plug body, a tip contact mounted in the end of the body for engagement with the base contact of the socket, a pair of outwardly sprung radially extending side contacts mounted on the body for engagement with the wall of the socket, a pair of radially extensible engagement means moveable between a first retracted position and a second position in which they engage the wall of the socket at a position spaced longitudinally of the plug away from the side contacts to prevent pivoting of the plug relative to the socket about the contact points of the side contacts with the wall of the socket Preferably the second position is variable to cater for different diameters of socket The engagement means may be spaced circumferentially of side contacts, preferably by ninety degrees Screw means may be provided to control movement of the engagement means, and may comprise a nut threaded on the body of the plug, screwing up of the nut causing radially outward movement of the engagement means To prevent unintentional release, the nut can be turned via a ratchet, thereby preventing reverse rotation The engagement means may comprise two arcuate shaped members which are arranged to slide in a circumferential direction in arcuate bores formed in the plug body with the bores opening at both ends at the surface of the plug body, the arcuate shaped members being longer than the arcuate bores so that one end of the arcuate shaped members is engageable with the nut while the other end of the arcuate shaped members protrudes from the plug body for engagement with the socket wall The arcuate bores may have grooves in their side walls to cooperate with projections on the arcuate shaped members to restrict the available travel of the arcuate shaped members and prevent them from falling out of the bores The invention will now be described in greater detail, by way of example, with reference to the drawings in which - Figure 1 is a side view of one embodiment of plug for use with a cigar lighter socket in accordance with the invention, Figure 2 is a longitudinal section of the plug of figure 1 inserted into a cigar lighter socket but before operation of engagement means, Figure 3 is a view similar to figure 2 but showing the arrangement after operation of the engagement means, and Figure 4 is a cross-section of an alternative embodiment Referring firstly to figure 1 a plug 1 for use in a cigar lighter socket of a vehicle comprises a plug body 3, a sprung tip contact 5 mounted in the end 7 of the bod 3 for engagement with the base contact of the socket, and a pair of outwardly sprung radially extending side contacts 9 mounted on the body 3 for engagement with the wall of the socket So far the construction of the plug is of a standard type and will not be dealt with in greater detail In addition to the above, the plug 1 is provided with a pair of radially extensible engagement elements 1 1 which are moveable between a first, retracted position (shown in Figure 2) and a second position (figure 3) in which the elements 1 1 it engage the wall of the socket at a position spaced longitudinally of the plug 1 away from the side contacts 9 to prevent pivoting of the plug 1 relative to the socket about the contact points of the side contacts 9 with the wall of the socket and in this way the plug is stabilised in the socket an, with sufficient tightness of the engagement, can support various articles such as mobile phone receptacles and/or speakers and amplifiers (not shown) Movement of the engagement elements 1 1 is controlled by a nut 15 associated with a screw thread 17 formed on the plug body 3 The arrangement is such that the further the nut 15 is screλved onto the plug body 3 (to the right in figure 1 ) the further outwardly the engagement elements protrude from the plug body The details of the construction of this embodiment are shown in the sectional views of figures 2 and 3 which show the plug 1 of figure in the cigar lighter socket The plug body 3 is formed of two parts separated on the section line so that only one of the parts is visible in these figures at 21 The body parts 21 are held together by an end cover 23 at the inner end (relative to the lighter socket which can be seen schematically here at 25) and by the nut 15 towards the outer end of the plug body 3 The body 3 has a central bore 27 which houses the electrical connections of the tip contact 5 and the side contacts 9 The tip contact 5 is spring urged outwardly by a spring 29 and is connected to an electrical contact rod 31 via a link 33 which bridges the side contact element 9 which is formed as a single piece of spring steel and extends across the bore 27 In addition to the electrical contacts 9 which embrace the inner wall 37 of the socket are the extensible engagement elements 1 1 These engagement elements 1 1 comprise two arcuate shaped members 39 which are arranged to slide in a circumferential direction in arcuate grooves 41 It will be appreciated that the grooves 41 are formed in both parts of the plug body 3 so that when the parts of the plug body are assembled together, the grooves 41 will form arcuate bores As can be seen, in the non engaged position, the nut 15 is screwed out so as to move to the left (in figure 2) so that both ends of the arcuate members 39 extend out of the grooves 41 When the nut 15 is screwed in, the end 43 of the nut 15 will engage the adjacent ends of the members 39 so as to push the members 39 around the grooves 41 to cause the other ends of the members 39 to engage the inner wall 37 of the cigar lighter socket 25 The tightness of this engagement will depend on the amount that the nut 15 is screwed in The arcuate shaped members 39 are prevented from slipping out of the grooves 41 when the plug is outside the socket by the provision of arcuate inner grooves 47 provided in the base of the grooves 41 which cooperate with projections 49 on the members 39 which limit the movement of the members 39 in the grooves It will be observed that the engagement provided by the engagement elements 1 1 is of a positive non springy type and it will also be seen that the engagement points of these elements 1 1 are spaced both longitudinally and circumferentially from the side contacts 9 thus preventing any pivotal action of the plug 1 in relation to the socket 25 In use, equipment intended to be supplied with electricity from the socket 25 can be mounted on the outer end 45 of the plug body 3 in any suitable way (not shown) To use the plug with the apparatus attached thereto, the nut 15 is first unscrewed to allow movement of the engagement elements 1 1 to a position in which the plug can be inserted in the socket 25 The plug 1 is then inserted in the socket 25 and the nut 15 is screwed in until engagement of the engagement elements 1 1 with the inner surface 37 of the socket is achieved Full tightening of the nut 15 will ensure a solid fit of the plug in the socket and provide a stable base for the apparatus attached thereto Figure 4 shows an alternative embodiment With the exception of the nut 15', this embodiment does not differ from that of figures 1-3, and therefore no specific description of the remainder of the embodiment will be given In this embodiment, the nut 15' comprises two distinct parts, 15a and 15b The inner ring 15a lies around the plug body 3 and is threaded on its inner surface At its face closest the tip 7 of the plug, the inner ring interengages with the arcuate members 39 as described above The outer ring 15b lies around the inner ring 15a and can rotate relative thereto Thus, the inner ring 15a cannot be rotated directly by a user, or at least not easily Between the inner and outer rings 15a, 15b is a ratchet 50 Ratchets are well known per se and do not therefore need further explanation In this case, the ratchet 50 is arranged such that rotation of the outer ring 15b in a tightening direction (i e so as to move along the thread towards the tip 7) causes the ratchet to engage and drive the inner ring Conversely, rotation of the outer ring 15b so as to loosen causes the ratchet to slip, the inner ring 15a then not being driven In this way, it is ensured that the plug 1 cannot be accidentally loosened As illustrated, the ratchet is formed on a radial face between an outwardly extending ridge on the inner ring 15a and a corresponding longitudinally displaced inwardly extending ridge on the outer ring 15b However, this is not essential and the ratchet could, for example, be formed on the cylindrical plane lying between inner and outer rings It will be understood that additions to or modifications of the above described embodiment are possible within the scope of the invention For example while the engagement means has been shown as arcuate members in arcuate grooves, these could be replaced by levers, suitably of "L" shape pivoted to the body 3 and acted on by the nut 15, the levers being pivoted at the left hand base of the "L" while the nut acts on one leg of the "L" and the other leg of the "L" provides the contact with the interior of the socket Other expanding devices could be used

Claims: CLAIMS: 1 A plug for use in a cigar lighter socket of a vehicle comprising a plug body, a tip contact mounted in the end of the body for engagement with the base contact of the socket, a pair of outwardly sprung radially extending side contacts mounted on the body for engagement with the wall of the socket, a pair of radially extensible engagement means moveable between a first retracted position and a second position in which they engage the wall of the socket at a position spaced longitudinally of the plug away from the side contacts to prevent pivoting of the plug relative to the socket about the contact points of the side contacts with the wall of the socket 2 A plug as claimed in claim 1, wherein the second position is variable to cater for different diameters of socket 3 A plug as claimed in claim 1 or 2, wherein the engagement means are spaced circumferentially of side contacts 4 A plug as claimed in claim 3, wherein the engagement means are spaced by ninety degrees from the side contacts 5 A plug as claimed in any preceding claim, wherein screw means are provided to control movement of the engagement means 6 A plug as claimed in claim 5. wherein the screw means comprises a nut threaded on the body of the plug, screwing up of the nut causing radially outward movement of the engagement means 7 A plug as claimed in claim 6 wherein the nut comprises a threaded member threaded on the body of the plug and a mutually rotatable sleeve around the threaded member, a ratchet between the two allowing the threaded member to be tightened 8 A plug as claimed in claim 6, wherein the engagement means comprise two arcuate shaped members which are arranged to slide in a circumferential direction in a. cuate bores formed in the plug body with the bores opening at both ends at the surface of the plug body, the arcuate shaped members being longer than the arcuate bores so that one end of the arcuate shaped members is engageable with the nut while the other end of the arcuate shaped members protrudes from the plug body for engagement with the socket wall 9 A plug as claimed in claim 7, wherein the arcuate bores have grooves in their side walls to cooperate with projections on the arcuate shaped members to restrict the available travel of the arcuate shaped members and prevent them from falling out of the bores 10 A plug for use in a cigar lighter socket of a vehicle and substantially as described herein with reference to the drawings

Inventors: LOCKWOOD TONY, LOCKWOOD, TONY
Applicants: HOSIDEN BESSON LTD, LOCKWOOD TONY, HOSIDEN BESSON LIMITED, LOCKWOOD, TONY
Application year: 1999
Main classification: H01R24
IPC codes: B60N3, H01R13, H01R24