| 摘要 |
A flotation device for causing an article to float if accidently dropped into water has protection from being triggered unless submerged. The flotation device includes a casing, a compressed gas cartridge, a pierce head biased by compression of a firing spring, at least one trigger, a dissolvable ring, and a balloon. The at least one trigger passes through, respectively, at least one trigger orifice formed in the casing. So long as a chamfered end of the at least one trigger is held by the dissolvable ring in abutment with a chamfered trigger groove in the pierce head, the pierce head is held against the biasing force of the biasing spring. A water control feature is characterized by a rim of an end cap being narrowly spaced from the casing, thereby forming a water passage therebetween. The width of the water passage between the end cap and the casing is such as to allow water to pass therethrough to the dissolvable ring only if under hydrostatic pressure of submergence. Once water passes through the water passage, the water will contact the dissolvable ring and thereupon cause it to disintegrate. The at least one trigger will then be forced upward by the chamfered trigger groove as the dissolvable ring disintegrates until the chamfered end of each trigger clears the pierce head. The firing spring will thereupon cause the pierce head to move toward the compressed gas cartridge. Upon contact, a pin point of the pierce head will pierce the compressed gas cartridge. Escaping compressed gas fills the balloon and results in a positive buoyancy which floats an attached article.
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