Hydraulic and earth engineering – Diving
Reexamination Certificate
2001-08-22
2004-10-19
Will, Thomas B. (Department: 3671)
Hydraulic and earth engineering
Diving
C441S123000
Reexamination Certificate
active
06805519
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to life jackets and other personal flotation devices (“PFDs”), and in particular to the prevention of airway submersion as a novel addition to the classic approach which is to recover the victim after they fall forward onto their face submerging their airway. Concurrently the instant invention continues to improve traditional face down corrective turning action. Central to the prevention of airway submersion is the separation of the centers of ballast and buoyancy. This not only creates increased torque around the axis of rotation that parallels the spine, but because of the anterior posterior separation creates a new axis of rotation around an axis that passes side to side through the thorax. Further improvements in controlling movement of the head, side to side, reduces the amount of torque required for reliable corrective turning action. This results in either decreased bulk of the buoyant moment or the amount of fluid or solid ballast needed to achieve improved airway protection for either inflatable or inherently buoyant personal flotation devices. With increasing concern about passive aspiration leading to drowning while face up in a mounting sea state the current embodiment includes oral nasal airway protection. Due to the morbidity and mortality of rapid onset hypothermia immediate removal from cold water requires inclusion of a personal raft within the PFD that incorporates rapid inflation, and stability in choppy seas and means to survive until rescued. The present invention also provides a garment integrated multi-chambered personal flotation device, life jacket, and the like.
2. Description of the Prior Art
Extensive pool and wave tank testing of fielded and prototype personal flotation devices (“PFDs”) on divergent body types indicates the clear need for continued improvement in airway protective performance. None of the jackets tested at several joint international efforts reviewing testing methodologies provided 5-second recovery of the test subjects.
Corrective turning as assessed by every government agency has been restricted to the tester assuming a horizontal face down position taking three strokes, then the administrator assess whether the individual is rolled into a face up position within 5 seconds. Past PFD designs relied upon the common understanding and practice of placing the PFD's buoyancy high on the chest. All current PFDs tested by the author fail to provide airway protection. There have been PFD recalls and refusal to grant reciprocal approval to product already in the field based on current concerns of the inadequacy of test methodologies. Some agencies instruct their test subjects to place the arms at the sides, legs together and stretch out the back as a simulation of unconsciousness. This methodology was introduced to allow comfortable recreational life jackets to be approved. The use of this methodology for approval of commercial open ocean life jackets has precipitated the global current crisis, with agencies from one country recalling product from another country. The United States Coast Guard (“USCG”) is currently increasing the rigor of testing by the inclusion of new tests more accurately assessing the capacity to commercial jackets to roll an unconscious victim from any position into an airway protected position within 5 seconds as mandated by the Code of Federal Regulations. The current challenge to improve the accuracy of testing is seriously compounded by a lack of PFDs capable of withstanding close scrutiny.
Recent joint Canadian and US wave tank testing of a international selection of “safety of life at sea” (“SOLAS”) class PFDs disclosed that the ability of any life jacket to provide surface airway protection is constrained by the same laws of physics. Even if one is turned face up in mounting seas at very low wave height and frequency the face is awash in waves. As the seas mount, the ballast of the body is driven down in the trough of the wave and the head completely submerged. The buoyant means about the neck if secure extracts the victim in a cyclic plunging action. Thus safety and survival at sea is dependent upon being able to immediately remove oneself from the sea as quickly as possible to avoid hypothermic induced unconsciousness and cumulative aspiration secondary to splashing waves or total submersion that occurs in even relatively mild seas.
The vast majority if not all current jackets fail to turn an unconscious victim who enters the water face first, but since face first water entry is not part of any PFD evaluation program this finding remains unknown therefore unaddressed. Current life jackets also possess a Danger Zone, defined as the vertical position in the water from which if the wearer passes out they then fall face forward into an airway submerged moment of stability. Until now the sole management of the Danger Zone was avoidance. The average user of PFDs is ignorant of the consequence of floating in the danger zone. In fact contrary to the lethal consequences of floating upright in the water column it feels intuitive to the uniformed. The vertical position is the ideal position from which to scan or signal rescue efforts. When you float upright it is easier to monitor the horizon behind you as well as that portion in front of you.
The body has highly developed postural muscles that in coordination with the vestibular apparatus of the inner ear maintain our vertical position in space. Prior jackets relied upon well-established principles that the buoyant moment belonged high on the chest in order to optimize airway protective turning. The prior art has relied strictly upon the use of buoyant means to generate the torque needed for turning and like a sail boat that had lost it's lead keel the purely buoyant PFD suffered from a lack of orientation, that is there are points of stability that are facedown as well as face up. Hence the urgent need to identify and remedy the Danger Zone.
The prior art is restricted to very severe limits on the angle of flotation of the body off of vertical as one means to avoid entering the Danger Zone. That is if a jacket floats the wearer closer than 20 to 30 degrees off of vertical it would not pass testing and would not be approved for use. At issue is that prior Life Jackets allow the center of gravity of the jacket to be balanced above the center of buoyancy by the conscious wearer floating upright in the water column as they want to be when eagerly trying to spot search and rescue efforts. The intuitive element is that if a PFD allows the center of gravity to be located directly above the centroid of buoyancy the system is in balance and so requires very little muscular movement to maintain this position in gravity. However, the problem occurs as the water environment quickly wicks away the body's heat leading to hypothermia, obtundation and eventually loss of consciousness. Upon loss of consciousness the victim can no longer maintain their vertical position in space, they can not even hold their head erect. The debility is so complete they cannot remove their face from the water.
Reviewing the mechanics of the Danger Zone, while conscious the victim can effortlessly balance themselves upright but when the head drops forward the center of gravity suddenly also shifts forward, and the individual slumps face down.
The entire global PFD community currently accepts the SOLAS standard for turning. A SOLAS Approved Life Jacket will roll an unconscious victim from any position into and airway protected position within 5 seconds. However that same community relies some variation of the Three-Stroke Test to confirm performance to that standard. PFD design has come to rely upon the assistance provided by the tester to the serious detriment of performance. One current test methodology simulates unconsciousness by instructing the tester to take three strokes, pull the arms to the sides, place the legs together, straighten the back then drop the head. This very complex maneuver
Daniel S. Polley, P.A.
Mayo Tara L.
Will Thomas B.
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