Immersion responsive sensor

#1. Field of the Invention

#The present invention relates to apparatus responsive to immersion in water to complete an electrical circuit through which a signalling means is energized from an electrical energy source.

#2. Description of the Prior Art

#FIG. 1 is a front elevation diagrammatic view of a signalling apparatus utilizing the preferred immersion responsive sensor in accordance with the present invention, with the apparatus being illustrated in the inverted position;

#FIG. 2 is a top plan view of the embodiment shown in FIG. 1;

#FIG. 3 is a fragmentary diagrammatic illustration of an alternative embodiment of the immersion responsive sensor illustrated in FIG. 1;

#Referring now to the drawings in detail and initially to FIGS. 1 and 2 thereof, a typical signalling apparatus, or immersion responsive apparatus, generally referred to by reference numeral 20 is shown. This apparatus 20, which for illustrative purposes will be described as a signalling lamp for providing a visual signal upon immersion of the apparatus 20 in water, such as salt water or fresh water, preferably comprises a housing 22, which preferably contains the electronic circuitry, such as illustrated in FIGS. 11, 12 or 14 depending on whether it is a fresh water (FIG. 11) or salt water (FIGS. 12 and 14) responsive apparatus, respectively, a signalling lamp 24 which is turned on in response to the completing of an electrical path to be described in greater detail hereinafter, a switch 26 overriding the operation of the device to turn it off and/or on manually, and a pair of electrically conductive sensing elements which, in the example shown in FIG. 1, preferably comprise an outer electrically conductive element 28 and an inner electrically conductive element 30 which is surrounded by the outer conductive element 28. In addition, as illustrated in FIG. 1, by way of example, if desired the assembly may comprise mounting means such as loops 32 and 34 on the outside thereof for enabling the threading of a strap therethrough for mounting the apparatus 20 on the user thereof. For purposes of illustration, the apparatus 20 is shown upside down in FIG. 1, the preferred normal manner of use being with the sensing elements 28 and 30 facing in a direction normally closest to the water and the signalling lamp 24 facing in a direction away from the water. As illustrated in FIG. 2, the sensing elements 28 and 30 are preferably arranged so as to both protrude from housing 20 with inner conductive element 30 protruding by a smaller longitudinal distance than outer conductive element 28, the length of inner conductive element 30 being less than the length of outer conductive element 28 by a sufficient amount to prevent inadvertent electrically conductive contact with the inner conductive element 30 prior to immersion of the apparatus 20 in water. In addition, as shown and preferred in FIGS. 1 and 2, the outer conductive element or shield for the inner conductor 30, preferably includes a pair of longitudinally extending slots 36 and 38 which preferably extend the full length of the outer conductive shield 8. These slots enable the venting of air from within the interior of the outer shield element 28 at substantially any depth of immersion of the sensing elements 28 and 30 in water less than total immersion while preventing the inadvertent entry of splash water prior to such immersion. In this manner, water may enter within the outer shield element 28 interior to contact the inner conductive element 30 and complete an electrical circuit path between the signalling lamp 24 and the energy source therefor at immersion depths where the water pressure is normally insufficient to cause such entry without venting of the air. In addition, the slots 36 and 38 which extend at least substantially the full longitudinal extent of the outer electrical shield 28 act as a waveguide to restrict electromagnetic, RF and electrostatic interference from entering through the outer shield 28. Thus, outer electrical shield 28 provides a circumferential electrical shield for the inner conductor 30 against both transient and continuous electromagnetic, RF and electrostatic interference to prevent inadvertent turn on of the signalling lamp 24 as a result of such interference.

#Referring now to FIGS. 3 and 4, an alternative embodiment of the sensing element arrangement 28-30 of FIGS. 1 and 2 is shown. Specifically, instead of providing longitudinal slots 36 and 38 in outer conductive shield 28a of FIG. 3, a plurality of apertures 40 are dispersed about the circumferentially surrounding peripheral portion of outer conductive shield 28a at a plurality of longitudinal levels so as to enable the venting of air from within the interior of the outer shield 28a at substantially any depth of immersion of elements 28a -30a in water less than total immersion while preventing the inadvertent entry of splash water prior to such immersion, these apertures 40 functioning in the same fashion as longitudinal slots 36 and 38 of the embodiment previously described with reference to FIG. 1.

#Referring now to FIGS. 5 and 6, still another alternative embodiment of the sensing element 28-30 arrangement previously described with reference to FIG. 1 is shown. In this arrangement, the outer shield is preferably formed of a non-conductive material such as a thermoplastic as opposed to being formed of a conductive material as in the previously described embodiments. This outer non-conductive shield 42 preferably includes a plurality of apertures 44 similar in location and purpose to apertures 40 previously described with reference to the embodiment of FIGS. 3 and 4. As shown and preferred in FIGS. 5 and 6, a pair of inner conductive elements 46 and 48 are preferably located within the interior of the outer shield 42. These inner conductive elements 46 and 48 preferably have a length or longitudinal extent which is less than that of the outer non-conductive shield 42 by a sufficient amount to prevent inadvertent electrically conductive contact with the inner conductive elements 46 and 48 prior to immersion in water. It should be noted in the embodiments illustrated in FIGS. 1 through 6, the outer shield 28, 28a or 42 is preferably open at the top thereof to enable entry of water therethrough. Furthermore, although not shown, if desired, outer non-conductive shield 42 may be slotted in a fashion similar to that previously described with reference to outer conductive element 28 of FIG. 1 as opposed to utilizing the dispersed apertures 44.