GB2089015A - Improvements in waterproof light emitting devices - Google Patents

Abstract

A torch or flash-light has a casing made in one piece to which is fixed in sealing-type fashion a transparent head 12 which is preferably screwed to the casing to provide a tight waterproof closure. The electrical switch 36 for controlling the operation of the device is magnetically coupled from a movable switch member 26 on the outside of the casing carrying a magnet 24 to switch contacts 38, 40 within the casing so avoiding the necessity of any opening for a switch. <IMAGE>

Description

SPECIFICATION Improvements in waterproof light-emitting devices This invention relates to waterproof lightemitting devices including torches and warning devices for giving high intensity light flashes.

High intensity light flashes can be provided using simple electronic circuitry powered by conventional low voltage dry batteries but the circuitry will not work or work efficiently in wet or damp conditions. Therefore. the housing for such devices must be waterproof and this is particularly critical when the device is for use as an emergency device carried by a boat, ship or yacht.

It is thus desirable that the casing for such a device have no unnecessary openings through it.

Simiiar problems arise with torches which are used and stored under wet or damp conditions.

It is therefore an object of this invention to provide light-emitting devices which will remain waterproof even if stored under damp conditions.

According to the invention there is provided a light-emitting device comprising a water-tight casing made in one piece for housing one or more electric batteries, a transparent or translucent head removably joined to the casing in sealingtight fashion, electrical switch contacts within the casing for controlling the actuation of the lightemitting device, and a switch on the outside of the casing including a magnet movable between a first position and a second position, in one position of the switch the electrical switch contacts being in the "off" position and in the other position of the switch the contacts being in the "on" position, the magnetic flux from the magnet passing through the housing and moving the electrical switch contacts between the "on" and "off" positions depending upon the position of the switch In the lighting devices of the invention therefre, a moisture- and water-proof casing is possible since no physical Opening of the casing is required for a switch. Thus the casing can be continuous within the electrical contacts wholly within the casing and the switch carrying the magnet mounted wholly outwardly of the casing, the contacts being magnetically coupled to the switch through the casing.The casing must of course be permeable to a magnetic flu; but if, as prefen-ed, the casing is moulded from synthetic plastics material this is not a problem.

In one embodiment of the invention the light-emitting device provides repeating high intensity light flashes to give a waming or to attract attention. According to that embodiment there is provided a device comprising a water-right casing for housing one or more electrical batteries, an electronic circuit for generating a charge to be discharged intermittently through a discharge tube to provide repeating high intensity flashes of light visible through the head of the device, and the magnetically coupled switch means including electrical contacts within the casing and movable magnetic switch member on the outside of the casing, whereby the electrical contacts are magnetically coupled to the switch member on the outside of the casing for opening and closing the switch contacts.

According to another embodiment of the invention the light-emitting device is a torch in which case the switch means complete a circuit between batteries housed in the casing and an electric bulb provided with a reflector to give a beam of light.

Preferably, the magnetically coupled switch means includes electrical contacts positioned within the casing which are resiliently biased towards their open position but are movable to their closed position under the effect of a magnetic field from the magnet is not sufficient casing carries a permanent magnet and the switch is movable between a position where the magnetic field from the magnetic is not sufficient to overcome the bias and move the electrical contact to the closed position and a position when the magnetic field does overcome the bias and the electrical contacts then move to the closed position.

In a preferred embodiment of the invention, the casing and the transparent or translucent head are screwed to one another by corresponding screwthreads. A resilient seal such as an O-ring seal can be provided at the join between the head and the casing to complete a water- and moisture-tight seal. An intermediate bowl member may be trapped between head and casing for supporting the discharge tube and electric circuit or bulb and reflector. This bowl is therefore readily removable after removal of the head to allow replacement of the batteries within the casing.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an elevation of a warning light emitting device according to the invention; Figure 2 is a side elevation, partly broken away, and with the head unscrewed, of the warning device; Figure 3 is an axiai section taken along the line 3-3 of Figure 1; Figure 4 is a longitudinal section taken along the line 4-4 of Figure 3; and Figure 5 is a section similar to Figure 3 of a torch according to another embodiment of the invention.

The light-emitting warning device 10 as shown in the drawings has a transparent or translucent head 1 2 and a substantially cylindrical hollow body 1 4 for housing dry batteries 44. Between the head 12 and body 14 is an intermediate bowl 1 5 for supporting a discharge tube 46 and electronic circuitry 1 7 attached to a p.c. board 19.

The head and body are tightly screwed together by a thread 1 8 formed internally of the head and a mating thread 20 formed externally of the body.

The seal provided by the mating threads 1 8 and 20 is supplemented by an O-ring seal 1 6 which is tightly wedged between a flat annular shoulder 21 on the body and the stepped lever end 23 of the head.

A circular magnet 24 is incorporated in a rotatably movable circular dial 26 having a knurled edge. The magnet 24 and dial 26 are rotatably carried on a mounting 28 on the outside of the body 24, the dial being rotatable about a central spigot 54 upstanding from the mounting 28. The dial is held in place by a cap 56 fixed to the spigot by a screw 58.

As best shown in Figure 3, within the body 14 is a magnetically operated switch 36 having contacts 38 and 40. These are movable between open and closed positions under the effect of the magnetic field of the magnet 24. Thus when the magnet is brought directly above the switch 36 as shown in Figure 3, the magnetic field causes the two contacts 38 and 40 to overcome the resilient bias which normally keeps them apart and so they close and make contact. However, when the dial 26 is rotated to move the magnet away from that position, the contacts move apart and open the switch.

The switch 36 is provided between the batteries 44 and the electronic circuitry 1 7 and so controls the energisation of the circuitry. The circuitry 1 7 is conventional. The low voltage from the batteries 44 is converted to a high voltage charge which is stored in a capacitor 70 and intermittently discharged through the discharge tube 46 to give a high intensity light pulse.

At the lower end of the body 14 is a coil spring 41 which contacts one pole of the lower battery.

This spring is connected to a strip of metal 42 which extends up the side of the body and contacts a contact 43 on the side of the bowl 1 5 and a wire 43a leads to the switch 36. The positive pole 50 of the upper battery 44 contacts a central contact 52 on the bowl to complete the connection of the circuitry 1 7 to the batteries via a wire 48.

To enable the batteries 44 to be replaced, the bowl 1 5 can be removed after taking the head and body apart. This avoids the use of another join, e.g.

at the lower end of the body, through which moisture could enter. The provision of the contacts 43 and 52 enables the bowl to be removed and replaced easily.

As best seen in Figure 4, a number of radially inwardly directed fins 60 are provided integrally moulded with the body 14. These centre the electric batteries 44 and prevent contact between the sides of the batteries and the strip 42. Two further small fins 62 are provided and the strip 42 is wedged between them to hold it in place. At the lower end of the body 14, the coiled spring 41 is wedged in place against the radial fins 60.

The lower end of the body 14 away from the head 12 had a lug 31 through which is a hole 32 for fixing a holding strap or the like. Around this lug are two segmental flanges 34 which project outwardly beyond the lug and so provide supports to enable the device to stand upright on that end.

Because of the required build-up of high voltage in the capacitor 70, this is only possible under dry conditions, and dampness, e.g. on the p.c. board 19, would prevent the build-up and probably operation of the circuit. Therefore the device has the advantage that the inside of the head and body can be kept waterproof because only a single join between them is provided and that is designed to be water-tight. Also the on/off switch for the circuit does not require an opening in the casing since the switch 36 is magnetically coupled to the dial 26.

Referring now to Figure 5 this shows a torch 80 according to the invention. The torch is in many ways identical to the warning device 10 shown in Figures 1 to 4 and so only the differences will be described.

The torch has a transparent cover 1 2a fixed to the housing 14 in a similar way to the head 12.

Between the cover 1 2a and the body 14 is a conical reflector 82 at the centre of which is positioned an electric bulb 84. One contact of this bulb is arranged to be connected to the pole 50 of the battery 44 through the contact 52.

Additionally the circuit is completed through the magnetic switch 36 and a contact 43 which contacts the strip 42. A magnet 24 is provided in an identical fashion to control the operation of the magnetic switch 36 so that the bulb can be illuminated when the switch 36 is closed with the magnet in one position and shut-off when the magnetic switch is opened with the magnet moved to the other other position.

Claims (6)

1. A light-emitting device comprising a watertight casing made in one piece for housing one or more electric batteries, a transparent or translucent head removably joined to the casing in sealing-tight fashion, electrical switch contacts within the casing for controlling the actuation of the light-emitting device, and a switch on the outside of the casing including a magnet movable between a first position and a second position, in one position of the switch the electrical switch contacts being in the "off" position and in the other position of the switch the contacts being in the "on" position, the magnetic flux from the magnet passing through the housing and moving the electrical switch contacts between the "on" and "off" positions depending upon the position of the switch.

2. A' light-emitting device as claimed in Claim 1 in which the electrical contacts positioned within the casing are resiliently biased towards their open or "off" position but are movable towards their closed or "on" position under the effect of a magnetic field.

3. A light-emitting device comprising a watertight casing for housing one or more electrical batteries, an electronic circuit for generating a charge to be discharged intermittently through a discharge tube to provide repeating high intensity flashes of light visible through a head of the device, and magnetically coupled switch means including electrical contacts within the casing and a movable magnetic switch member on the outside of the casing. whereby the electrical contacts are magnetically coupled to the switch member on the outside of the casing for opening and closing the switch contacts.

4. A light-emitting device as claimed in any preceding claim in which the head is screwed to the casing and an intermediate bowl member is trapped between the head and casing and that bowl member supports the light-emitting means and is provided with contacts for connection to the batteries, one of the contacts being positioned to contact one pole of the battery and the other contact being positioned to connect with a metal strip leading to the opposite pole of the batteries.

5. A flashing warning device substantially as herein described with reference to Figures 1 to 4 of the accompanying drawings.

6. A torch substantially as herein described with reference to the accompanying drawings.