ENVIRONMENTALLY PROTECTED SWITCH FOR WATER ACTIVATED DEVICES

CROSS REFERENCE TO RELATED APPLICATIONS

[001] This application claims priority, under 35 U. S. C. § 119(e), of U.S. provisional application serial No. 61/079,211 , filed on July 9, 2008, which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[002] The present invention relates to an environmentally protected switch for water activated devices, such as safety lights.

BACKGROUND OF THE INVENTION

[003] In order to provide persons in need of rescue with a prompt response in emergency situations, the prior art teaches signaling devices for use with personal flotation devices, such as inflatable life vests and the like. Such signaling devices, which typically comprise a small yet bright light source powered by a battery pack, improve the visibility of a person stranded in water by generating a noticeable flashing signal or strobe. A submersible switch may be included to activate the light source when placed in a conductive fluid, such as water. Still, a major drawback of these prior art devices is that the switch is not environmentally protected and in particular not splash resistant, therefore rendering the light source susceptible to accidental illumination resulting from activation of the switch by inadvertent splashing thereof. This is particularly acute in some applications, for example in fishing operations in heavy seas and the like where the wearer is being repeatedly submerged by waves without being in peril. Additionally, during winter months spray and humidity have a greater affinity for freezing which in many cases can also lead to inadvertent or accidental illumination.

[004] What is therefore needed, and an object of the present invention, is a switch for use with water activated devices, the switch being environmentally (e.g. splash and humidity) resistant in order to prevent accidental triggering (and thus illumination of the signalling device) thereof.

SUMMARY OF THE INVENTION

[005] More specifically, in accordance with the present invention, there is provided an environmentally protected switch for activating a signaling device powered by a battery and adapted for use with a conductive fluid. The switch comprises a housing comprising an open end and a sensing element received within the housing along a longitudinal axis thereof and coupled to the signaling device for providing an electrical path connecting the battery and the signaling device, a tip of the sensing element substantially flush with the open end. Upon submersion of the switch into the fluid and agitation of the switch to break a surface tension at an interface between the fluid and the open end, the fluid penetrates the housing to enable an electrical current to flow within the sensing element for closing the electrical path and activating the signaling device.

[006] In accordance with the present invention, there is also provided a method for activating a signaling device powered by a battery and adapted for use with a conductive fluid, the method comprising providing an environmentally protected switch. The switch comprises a housing comprising an open end and a sensing element received within the housing along a longitudinal axis thereof and coupled to the signaling device for providing an electrical path connecting the battery and the signaling device, a tip of the sensing element substantially flush with the open end. The method further comprises submersing the switch into the fluid and agitating the switch to break a surface tension at an interface between the fluid and the open end, thereby enabling the fluid to penetrate the housing and an electrical current to flow within the sensing element for closing the electrical path and activating the signaling device.

[007] Other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of specific embodiments thereof, given by way of example only with reference to the accompanying drawings.

BRiEF DESCRIPTION OF THE DRAWINGS

[008] Figure 1 is a front view of a life vest in accordance with an illustrative embodiment of the present invention;

[009] Figure 2 is a raised front view of a light source and an environmentally protected switch in accordance with an illustrative embodiment of the present invention;

[010] Figure 3 is a schematic diagram of an environmentally protected switch for activating a light source in accordance with an illustrative embodiment of the present invention; and

[011] Figure 4 is a side perspective view of an alternative light source for use with the environmentally protected switch in accordance with an illustrative embodiment of the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

[012] Referring now to Figure 1 , and in accordance with an illustrative embodiment of the present invention, a life vest, generally referred to using the reference numeral 10, will now be described. The life vest 10 is comprised of one or more chambers as in 12, which are filled with a buoyant material (not shown). In the case of an inflatable vest, the buoyant material is a gas, such as CO ₂ or air, which is introduced into the chamber(s) from a cylinder or the like (not shown), typically activated by means of a rip cord 14. Additionally, a back up oral inflation tube 16 is provided in order to maintain buoyancy or inflate the vest 10 when the cylinder is empty or inoperable. In order to improve the wearer's chances of being discovered, the outer visible part of the life vest 10 is typically manufactured from a bright material in yellow or day-glow orange. Additionally, the life vest 10 is equipped with a whistle 18 for generating an audible signal, reflective strips as in 20 and a signaling device such as a light source 22.

[013] Referring now to Figure 2 and Figure 3 in addition to Figure 1 , the light source 22 is interconnected via an insulated electrical cable 26 with a water proof battery pack 24, which provides power to drive the light source 22. The light source 22 illustratively comprises at least one high power Light Emitting Diode (LED) (not shown) suitable as both a flashing (e.g. according to a predetermined sequence, such as the well-known Morse code representation of SOS) and a steady state light source. Additionally, such high power LEDs are available in a variety of colours as well as infrared, and as a result it is foreseeable that a combination of different colours be included in order to provide a variety of illumination schemes. The light source 22 is illustratively water activated by an environmentally protected switch 28, which is coupled to the light source 22 via the cable 26. The switch 28 is illustratively positioned near the base of the life vest 10 to ensure proper immersion of the switch 28 as a wearer of the life vest 10 is submerged in a conductive fluid 30, such as water. The switch 28 illustratively includes a waterproof housing or shroud 32 covering a pin or probe member 34 (e.g. of the standard RCA connector type) comprising a pair of insulated conductors 36 and 38 for providing an electrical path between the battery 24 and the light source 22 for illumination thereof.

[014] Still referring to Figure 2 and Figure 3, it is desirable for an open end 40 of the shroud 32 to be substantially flush with a tip (not shown) of the probe member 34. In this manner, the probe member 34 is protected from penetrating and thus puncturing the life vest (reference 10 in Figure 1) or other flotation device (not shown) the light source 22 and switch 28 are illustratively mounted to, thus preventing damage to the device. In addition, the open end 40 of the shroud 32 being substantially flush with the tip of the probe member 34 enables the switch 28 to be made wave and splash resistant along a direction transversal to a longitudinal axis Z of the switch 28 as water drops or vapour (e.g. resulting from waves or splashing of the fluid 30 on the switch 28) are prevented from penetrating the shroud 32 and bridging the current between the conductors 36, 38, thus avoiding accidental triggering of the switch 28. Indeed, upon submersion of the switch 28 into the conductive fluid 30, due to the air pressure within the shroud 32 and to the surface tension of the fluid 30, without imparting a mechanical action on the switch 28, the fluid level remains substantially flush with the open end 40 of the shroud 32 and typically little or no fluid 30 penetrates the shroud 32, thus keeping the switch 28 deactivated.

[015] Still referring to Figure 2 and Figure 3, the switch 28 is illustratively activated by mechanical action (e.g. agitation thereof by a stranded user, heavy wave action, or the like), which breaks the surface tension of the fluid 30 thus enabling some of the fluid 30 surrounding the switch 28 to penetrate into the shroud 32. Once the fluid has penetrated within the shroud 32 up to a depth d where the fluid reaches the end of conductor 36, current flows between the ends of the conductors 36, 38, thus actuating the switch 28 to illuminate the light source 22. A threshold is therefore created wherein a slight amount of moisture, i.e. below the depth d, will not activate the switch 28 to illuminate the light source 22. Still, although the end of conductor 36 has been shown for illustrative purposes as being positioned at a greater distance (i.e. the depth d) from the tip of the probe member 34 than the end of conductor 38, it will be apparent to a person of skill in the art that both ends of the conductors 36, 38 may be positioned at the same distance from the tip of the probe member 34 without departing from the scope of the present invention. However, it is desirable for the ends of the conductors 36, 38 to be separated by a distance, which enables the flow of an amount of current sufficient to illuminate the light source 22.

[016] Still referring to Figure 2 and Figure 3, the shroud 32 advantageously protects the switch 28 from a variety of environmental conditions. Indeed, by preventing moisture to some degree from contacting the ends of the conductors

36, 38, the shroud 32 also prevents or at least reduces the possibility that the light source 22 is accidentally illuminated for example when cold ambient conditions would lead to spray or moisture freezing across the conductors 36, 38, thereby resulting in the formation of ice crystals and the like around the probe member 34 and creating a conductive circuit that would accidentally activate the switch 28.

[017] Still referring to Figure 2 and Figure 3, in order to ease the intake of the fluid 30 into the shroud 32 while maintaining many of the environmentally (e.g. splash) resistant characteristics, a plurality of apertures as in 42 may be provided on the shroud 32 at an end thereof opposite the open end 40 to allow a flow of air within the shroud 32. It is desirable for the apertures as in 42 to be large enough to ease fluid intake within the shroud 32 yet small enough to prevent excessive fluid penetration, thus ensuring that the switch 28 remains relatively splash resistant when submersed.

[018] Referring back to Figure 2, the switch 28 may also be provided with a plug 44 comprising a first sleeve 46 and a second sleeve 48, each sleeve 46, 48 adapted to be mated with the probe member 34 for manually activating or deactivating the switch 28. In particular, the sleeve 48 is illustratively made of a conductive (e.g. copper) material that enables the switch 28 to be brought to an "ON" state by creating an electrical contact between the probe member 34 and the sleeve 48 (and thus between the switch 28 and the conductive fluid 30 the switch 28 is immersed in) when the sleeve 48 is placed over the probe member 34. Similarly, the sleeve 46 is illustratively made of a dielectric material that brings the switch 28 to an "OFF" state by preventing any electrical contact between the probe member 34 and the sleeve 46 (and thus between the switch 28 and the conductive fluid 30). In this manner, the switch 28 can for example be deactivated (e.g. when the life vest 10 is not in use) to prevent accidental illumination of the light source 22, thus saving power from the battery (reference 24 in Figure 1 ).

[019] Still referring to Figure 2, in order to further prevent accidental illumination of the light source 22 a timer circuit (not shown) can be integrated into the light source 22 such that illumination of the light source 22 is only triggered provided that the switch 28 has been adequately submersed in the conductive fluid 30 for a predetermined amount of time, for example 60 seconds or the like. Additionally, a similar timer circuit can also be included to ensure that the light source 22 stays illuminated for a predetermined amount of time if the switch 28 is removed from conductive fluid 30.

[020] Referring now to Figure 4, in an alternative illustrative embodiment of the present invention, the light 22 can be replaced by an alternative light source 50 comprising one or more LEDs as in 52 and a battery compartment 54 covered with a suitable adaptor cap 56. The adaptor cap 56 provides the interconnections and electronics necessary to interconnect a control panel or the like (not shown) via an insulated electrical cable 58 with a battery (not shown) within the battery compartment 54 to allow for control of the illumination of the LEDs as in 52. Additionally, the battery pack (reference 24 in Figure 1 ), which is combined with the switch 28 and connected with the adaptor cap 56 via a second insulated cable 60, can be used to supplement the battery within the battery compartment 54.

[021] Referring back to Figure 1 , of note is that although the above light source 22 and switch 28 are shown in conjunction with a life vest 10, the light source 22 and switch 28 could also be used in conjunction with other flotation devices, such as inflatable rafts and the like, without departing from the scope of the present invention. In addition, the switch 28 may be used in a variety of applications with signalling devices other than (or in addition to) the light source 22. For example, the switch 28 may be used in alarm systems for the purpose of locating downed personnel in emergency situations. The switch 28 may also be used in conjunction with other water sensing devices (not shown) as an alarm for household applications (e.g. to prevent flooding in basements and garages or to sense high humidity environments in homes), for use on boats, or the like. In such applications, upon activation of the switch by immersion of the switch 28 into a fluid (reference 30 in Figure 4) for instance, a signal would illustratively be transmitted via an antenna or the like to an alarm device (not shown), such as a horn or siren, adapted to automatically generate an audio alarm.

[022] Still referring to Figure 1 , when used with a light source as in 22 for generating a visual alarm, the switch 28 of the present invention may also suitable for use in low-level lighting applications or for identifying exit ways or the like, in which case the desired lighting is illustratively only provided upon activation of the switch 28 (as discussed herein above). Moreover, in some applications it may be desirable for the switch 28 to be detachable from the light source 22 once the latter has been illuminated by activation of the switch 28 and this could illustratively be done by exerting a pulling force on the cable 26.

[023] Although the present invention has been described hereinabove by way of specific embodiments thereof, it can be modified, without departing from the spirit and nature of the subject invention as defined in the appended claims.