A cable lamp of this kind will include an electric cable that has a fluorescent tube fitting at one end thereof, a battery connector means connected to the other end thereof, said cable including two conductors which are each provided with connector means for detachable connection to a respective terminal of the battery, and further includes fluorescent tube lamp, and an electronic HF lamp ignition means.

A cable lamp of this kind has the advantage of providing a high light yield or luminous efficiency in relation to energy consumption.

It is important to be able to minimise the energy consumed by a lamp in relation to a given luminous flux, particularly in the case of water-going vessels, such as motorboats, yachts, and also with respect to cars and the like, which, in <BR> <BR> <BR> practice, carry only a single source of current in the form of a low voltage battery (12 volt accumulator). In order to enable the light source to be used comfortably, it will preferably be connected to the battery by means of a long cable that will allow the light source to be moved to a <BR> <BR> <BR> position located at a relatively long distance from the battery.

It is known to use to this end a cable lamp whose light source consists of a low-energy bulb, for instance a halogen bulb of good efficiency that can be operated on battery voltage. However, as a result of the requisite length of the lamp cable, the power losses in the cable become problematic.

These losses can be alleviated by using heavy gauge cable conductors, although this renders the. cable expensive and difficult to handle. It is also known to use a light source in the form of a compact fluorescent tube and to energise the tube with the aid of an ignition means fitted at each end of the cable. If the converter is placed at the battery end of the cable, the cable conductors will transmit high frequency noise, owing to the fact that the ignition means, or igniter, includes a high frequency converter. This means that at least the cable must be screened along the whole of its length, causing the cable to become relatively heavy, clumsy and expensive. If the HF device is, instead, placed in the proximity of the light source, the power loss in the cable will become problematic unless the cable conductors are given a heavy gauge, although this will again result in a cable which is heavy, difficult to handle and, above all, expensive. The HF device located in the proximity of the light source will, of course, also generate a high frequency disturbance.

The object of the present invention is to provide a cable lamp that can be connected to a low voltage battery and with which the aforesaid drawbacks are limited.

This object is achieved with an inventive cable lamp having the features set forth in the following independent Claim.

Further embodiments of the cable lamp are set. or in the following dependent Claims.

The invention is based on the commercial availability of energy-lean bulbs (for instance, bulbs of the type Osram Dulox EL) which include a compact fluorescent tube having connected directly thereto an HF ignition means which is powered by an AC or a DC mains voltage (230 volts). The energy-lean bulb has a conventional connection base (E14) and

can be connected to a rotatable bulb holder provided at one end of the cable. In accordance with the invention, a known converter is built into the battery connection means of the cable at that end of the lamp cable intended for connection to the battery, said converter being designed to convert 12 volts DC to 230 volts DC, such as to supply the cable with 230 volts DC. This enables the cable to be made relatively slender and flexible and also relatively long (for example, given a length of ca 100 m) without the occurrence of problematic power losses in the cable. The converter is screened in the battery connection means so as to generate no disturbing HF transmission that might otherwise disturb radio equipment and other electronic equipment in the vehicle. This obviates the need of screening the lamp cable. A converter of the kind in question that can convert 12 volts DC to 230 volts AC will preferably operate at a relatively high frequency, so that it can be given small dimensions. By giving the converter, and also a subsequently coupled smoothing unit, small dimensions there is afforded the additional advantage of enabling the converter and the smoothing device to be accommodated in a tubular leg of a terminal connection clip, wherewith one tubular leg of the terminal connection clip forms the main part of a screen housing in which the converser and smoothing device are enclosed and HF sealed. The clip leg will therewith also form cooling means for conducting away heat generated bi the converter. The clip leg also forms a protective converter housing.

In summary, there is obtained a cable lamp having a long, thin flexible cable with small energy losses and with which there can be used a commercially available fluorescent bulb with associated ignition means, wherewith the battery- connecting end of the cable may include a converter which is housed in a battery connector clip that also forms an HF sealed protective casing for the converter. Because of the

high luminous efficiency of the light source, the lamp can be powered for long periods of time by low capacity, low-voltage current sources, for instance lead batteries, solar cell panels and the like.

The invention will now be described in more detail with reference to the accompanying drawings, in which Fig. 1 is a schematic illustration of an inventive cable lamp connected to a battery; and Fig. 2 is a partial sectioned view of one terminal connector clip of the cable lamp.

The illustrated cable lamp 1 comprises a long cable 10 that includes two conductors 11 and 12. One end of the cable 10 is connected to a a conventional incandescent bulb fitting (bulb holder) 14. However, the light source used with the illustrated cable lamp 1 is an energy-lean bulb 20 of the type Osram Dulox EL, which includes a compact fluorescent tube 21 having connected directly thereto an HF ignition mean 22 that includes a conventional screw thread 23 corresponding to the screw thread of the conventional lamp-base of the fitting 14 (e. g. an E14 thread).

One conductor 11 is connected at the other end of the cable 10 to a first battery clip 30, while the other conductor 12 is connected to a second battery clip 40, said first clip 30 being shown connected to the positive pole of a 12 volt battery 2 and the second clip 40 being shown connected to the negative pole of said battery.

It will be seen from Fig. 2 that the first connection clip 30 typically includes two lever arms 31,32 that are mutually mounted on a pivot pin 33. The lever arms 31,32 may be made of an electrically conductive material and are biased for

pivotal movement by means of a spring (not shown), such that respective legs 311,321 of said arms will be biased towards one another, whereas the other legs 312,322 of said arms form manipulating legs that can be gripped with the hand so as to move the legs 312,322 towards one another against the force of said spring and therewith open the clip 30.'One leg, 322, is generally tubular and defines together with two separate end-pieces 323,324 a closed, sealed chamber 17 which is screened by electrically conductive material. The chamber 17 accommodates a converter 18. The converter 18 is connected to the arm 32 by means of a conductor 50, and is supplied with +12 volts. The converter 18 is also connected by means of a cable 51 to the clip 40 for connection to the negative terminal of the battery 2. The converter 18 includes a first conventional means for converting a direct current voltage of 12 volts to a high-frequency alternating current of mains voltage, and a second means for substantially rectifying the transformed high-frequency alternating current voltage so as to supply the conductor 11 with a 230 volt DC, whilst the conductor 12 is connected to the negative terminal of the battery 2. The energy-lean bulb 20 will operate equally as well at 230 volt DC and 230 volt AC. Because the converter 18 operates a a high frequency, for instance a frequency in the order of 40 kHz, the converter 18 may be made so small as to enable it to be accommodated in the clip 30 and so that the heat generated by the converter 18 will be so slight as to enable the clip 30 to function as a converter cooling means.

As evident from Fig. 2, the manipulating legs 312,322 of the clip are covered with insulating jackets 330,331, although it will be understood that both clips 30,40 may be covered with an electrically insulating covering with the exception of those surfaces that are intended for contact with the battery terminals.

Fig. 1 shows a conductor (51) whose one end is connected electrically'to the clip (40) and whose other end is connected to the converter (18) in the clip (30), so as to enable the converter to deliver a voltage of 230 volts.