This invention relates to lighting devices and is particularly concerned with portable, battery operated lights or torches. More specifically it provides a portable light designed for operation by a rechargeable battery and adapted for use in conjunction with a convention automobile cigarette lighter power outlet.

A cigarette lighter installation is standard equipment in most automobiles. Generally, this installation comprises a socket element usually fitted into the dash panel of the vehicle and a removable plug element which fits into the socket. The plug element carries an electric resistance

heater which is supplied with current from the electrical system of the automobile via contacts in the socket element when the plug is fully depressed into the socket.

There has been a tendency, particularly in recent years, for drivers and passengers not to smoke in vehicles, making the cigarette lighter installations redundant. The present invention provides a lighting device which may conveniently be stowed by insertion in the socket element of such an installation in lieu of the cigarette lighter plug element so as to be ready for use at any time and which will be charged automatically when so stowed.

Disclosure of Invention

According to the invention there is provided a lighting device for use in conjunction with the socket element of an automobile cigarette lighter of the kind having a socket element with electrical contacts and a removable plug element to plug into the socket element, said lighting device comprising: a body which has an elongate plug portion for insertion into the socket element of an automobile cigarette lighter installation and which defines a receptacle for a rechargeable battery; an electric lamp unit mounted in the body; electric contact means on the plug portion of the body to make electrical contact with the supply contacts of the cigarette lighter socket element; and electrical circuit means to supply power to the electric lamp from the battery and to supply power from said contacts to the battery for recharging the battery with power supplied from the automobile through the contacts of the cigarette lighter socket element.

Preferably the electrical circuit means comprises a voltage reducer to reduce the automobile supply voltage to a recharging voltage slightly above the nominal voltage of the

rechargeable battery. More particularly it may reduce a 12 voltage supply voltage to a recharging voltage in the range 1.5 to 6 volts.

Preferably further, the lamp unit is positioned to 5 shine forwardly from a front face of the body, the plug portion of the body is a rearwardly projecting rear end portion of the body, and the lamp unit and the battery receptacle are mutually oppositely offset laterally of a front to rear direction through the plug portion of the body.

10 Brief Description of Drawing

In order that the invention may be more fully explained, one particular embodiment will be described in some detail with reference to the accompanying drawing in which: Figure 1 is a front perspective view of a portable 15 light constructed in accordance with the invention;

Figure 2 is a rear perspective view of the light shown in Figure 1;

Figure 3 is a side view of the light; Figure 4 is a top view of- the light; 20 Figure 5 is a front end view of the light;

Figure 6 is a vertical cross-section on the line 6-6 in Figure 5; and

Figure 7 illustrates the electrical circuit of the light.

25 Best Mode of Carrying Out the Invention

The drawings illustrate a portable light having a body 10 comprised of a pair of body shells 11, 12 each forming one half of the body. The two shells 11, 12 may conveniently be injected moulded of a synthetic plastics material. The

30 body may be symmetrical about a central longitudinal plane and the shells shaped to two mirror image formations. It is possible to secure the two shells together so that the body * may be opened up for service but generally it is preferred that the body be sealed on assembly of the light.

Body 10 has a hollow front part 13 and a rear part in the form of a rearwardly projecting plug portion 14. The front body portion 10 is in the form of a flattened tubular barrel, having two flat sides 15 joined by cylindrically curved segments 16. The barrel thus has two generally semi-cylindrical lobes extending to laterally opposite sides of a central longitudinal direction through the plug portion 14 of the body. One of these lobes houses a lamp unit denoted generally as 17 and the other provides a receptacle for a rechargeable battery 18. The battery may be a rechargeable nickel-cadmium battery rated at 2.4 volts.

The lamp unit 17 comprises a dished reflector 19 which is fitted into an opening in the front face 20 of the body when the two body shells are brought together, an incandescent globe 21, fitted centrally within the reflector and a lens 22 held in position by a screw threaded knurled ring 23 which screws onto the outer rim of the reflector.

A metal contact member denoted generally as 25 provides a continuous electrical connection between the rear contact 24 of globe 21 and one side of the battery 18.

Contact member 25 is mounted between two lugs 26 on the body and comprises a resilient end leaf 27 to engage the globe contact 24 and a resilient end leaf 28 to engage the positive side of the battery. This provides a continuous positive connection to globe 21. A negative connection is provided by the operation of a switch denoted generally as 31.

Switch 31 comprises an arcuate slider 32 provided with a cam plate 33 which acts on a metal strip contact member 34. One end of contact member 34 permanently engages a U-shaped leaf contact member 35 installed in the plug portion of the body which also makes contact at 36 with the negative side of the battery 18. The other end of member 34 is formed as a leaf having a kink 37 and an out-turned leaf end 38. The leaf kink 37 cooperates with two notches 39, 40 in the switch cam plate 33 to define "on" and "off" conditions of the switch. The switch is illustrated in its "off" condition in which the kink 37 engages notch 39 in cam plate 33 and the

leaf end 38 is out of engagement with the globe 21. By sliding the switch slider in the direction of arrow 41 in Figure 6, the cam plate is moved to force the leaf end 38 into engagement with the outer or peripheral contact 42 of the globe and the kink 37 engages the smaller notch 40 in the cam plate to hold the switch in the "on" condition.

The arms of the U-shaped contact member 35 are formed with outwardly curved portions 43 which project outwardly through slots 44 formed at diametrically opposite sides of the plug portion 14 of the body. These portions serve as resiliently biased wiper contacts to contact the socket element of an automobile cigarette lighter installation and so provide a connection with the earth side of the vehicle electrical system. The nose 45 of the plug portion of the body is fitted with a central contact pin 46 loaded by a spring 47 to engage the active contact of the cigarette lighter socket and so' connect with the non-earthed side of the vehicle power supply. This contact is electrically connected via a wire 48 into the electrical circuit as illustrated in Figure 7.

If required the plug portion 14 of the body may also be provided with a pair of diametrically opposed bosses 50, which can be either fixed or spring-loaded, to ensure a firm fit within the cigarette lighter socket, some sockets being of slightly different sizes than others.

An indicator light 49 is mounted in the front face of the light body and connected into the electrical circuit as also illustrated in Figures 7.

As shown in Figure 7, contact 46 is connected with the positive side of battery 18 via an IN4004 diode 51, a

180ohm resistor 52 and a 3.9V Zener diode 53. Indicator light 49 is a light emitting diode and is connected between the positive and negative sides of the circuit through a 2kz resistor 54. When ^" the illustrated light is not in use, it can be stowed by pushing the plug portion 14 of the body into the socket element of an automobile cigarette lighter

installation. The plug then serves as a mounting member and its electrical contacts provide a continuous connection for supply of power to the battery for recharging. The illustrated circuit produces a voltage reduction to a recharging voltage of about 2.4 volts from a supply voltage of 12 volts. The combination of the Zener diode 53 and resistor 52 controls the charge current to the battery to within recommended levels for all fluctuation of battery voltage and it also reduces the current supplied to the battery as the battery voltage rises with charging. The IN4004 diode 51 serves as a one-way device providing reverse polarity protection. Thus, if the automobile power source connections are reversed for any reason there will be no damage to the battery 18. Diode 54 also prevents discharge of battery 18 through light 49 or in the event of a short between the plug contacts 35, 46

Industrial Applicability

The invention enables provision a very convenient light for automobiles which is extremely compact and can be simply stowed by insertion with a cigarette lighter socket where it will be automatically recharged for use at any time.