U.S. patent application number 10/232771 was filed with the patent office on 2003-03-27 for variable limits setting dive computer.
Invention is credited to Hollis, Robert R..
Application Number | 20030056786 10/232771 |
Document ID | / |
Family ID | 42133704 |
Filed Date | 2003-03-27 |
United States Patent
Application |
20030056786 |
Kind Code |
A1 |
Hollis, Robert R. |
March 27, 2003 |
Variable limits setting dive computer
Abstract
A variable limits setting dive computer for SCUBA divers which
permits individual diver selectable time values for different diver
physiology for commencing the ascent on the dive time remaining
display, with diver controlled overrides, together with a tissue
loading bar graph with diver pre-determined and variable visual and
audible alarms actuated by the selected setting on said bar
graph.
Inventors: |
Hollis, Robert R.; (San
Leandro, CA) |
Correspondence
Address: |
BRUCE & MCCOY
ONE KAISER PLAZA
STE. 2360
OAKLAND
CA
94612
US
|
Family ID: |
42133704 |
Appl. No.: |
10/232771 |
Filed: |
August 30, 2002 |
Current U.S.
Class: |
128/201.27 |
Current CPC
Class: |
B63C 2011/021 20130101;
B63C 11/02 20130101 |
Class at
Publication: |
128/201.27 |
International
Class: |
B63C 011/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 3, 2001 |
JP |
2001-265253 |
Claims
We claim:
1. A variable setting dive computer for a SCUBA diver which permits
establishing variable diver selected tissue loading limit values
for a dive comprising data sensors for said computer including at
least water depth and elapsed time, computer means having software
based on the Navy Dive Tables for integrating the output from said
sensors and producing a computer output in response thereto, a data
display including a tissue loading bar graph which is actuated by
said output from said computer and indicates when DECO status has
been reached, and selection means operable by a diver to select a
value on said tissue loading bar graph for triggering at least one
alarm when said value is reached during a dive by said output from
said computer activating said TLBG in response to integrating the
output from said sensors.
2. The variable setting dive computer of claim to 1 wherein said
TLBG is comprised of a series of segments disposed along a portion
of the periphery of said data display and which progressively
appear or disappear on the display in accordance with the output of
said computer.
3. The variable setting dive computer of claim 2 wherein said
segments are comprised of circles varying both in size and wall
thickness progressively from small and thin to large and thick as
the diver's tissue loading increases.
4. The variable setting dive computer of claim 1 wherein said
alarms include an audible tone and a colored LED positioned
adjacent to said TLBG.
5. A variable setting dive computer for a SCUBA diver which permits
establishing variable diver selected tissue loading limit values
for a dive comprising data sensors for said computer including at
least water depth and elapsed time, computer means having software
based on the Navy Dive Tables for integrating the output from said
sensors and producing a computer output in response thereto, a data
display including a tissue loading bar graph which is actuated by
said output from said computer and indicates when DECO status has
been reached, said TLBG being comprised of a series of segments
disposed along a portion of the periphery of said data display and
which progressively appear or disappear on the display in
accordance with the output of said computer, said segments being
comprised of circles varying both in size and wall thickness
progressively from small and thin to large and thick as the diver's
tissue loading increases selection means operable by a diver to
select a value on said tissue loading bar graph for triggering at
least one alarm when said value is reached during a dive by the
output from said computer activating said TLBG in response to
integrating the output from said sensors.
6. The variable setting dive computer of claim 5 wherein said
alarms include an audible tone and a colored LED positioned
adjacent to said TLBG near said indicator of DECO status.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a novel method and
apparatus for underwater data sensing and processing for SCUBA
divers. More particularly, it relates to a portable underwater
computer having data sensors, a software program and processor, and
a specialized display and control. The computer provides integrated
visual information to a diver numerically and graphically and
permits the diver to set variable limits on his dive parameters to
provide visual and aural warnings with respect thereto.
[0003] Still more particularly, the present invention provides a
variable limits setting dive computer for SCUBA divers which
permits individual diver selectable time values, for different
diver physiology, for commencing the ascent on the dive time
remaining display, with diver controlled overrides, together with a
tissue loading bar graph with diver pre-determined and variable
visual and audible alarms with respect to the commencement of
ascent from the dive actuated by the selected setting on said bar
graph.
[0004] 2. Description of the Prior Art
[0005] The use of dive computers in one design or another for the
purpose of assisting SCUBA divers is well known in the prior art.
However, despite the numerous designs, structures, and forms of
apparatus which have been developed and disclosed by the prior art,
specifically for the accomplishment of the objectives, purposes,
and requirements of SCUBA divers, the various devices, machines,
and methods which have been heretofore devised and utilized to
accomplish this goal consist basically of obvious configurations,
combinations, and arrangements of well known apparatus. This will
become apparent from the following consideration of the closest
known and relevant prior art.
[0006] The use of dive computers to help SCUBA divers to avoid
"decompression sickness" (DCS) is well developed in the art and is
comprehensibly disclosed in the Description of the Prior Art
section of U.S. Pat. No. 4,882,678 for a Data Sensing and
Processing Device for SCUBA Divers, issued Nov. 21, 1989, to
Hollis, et al. The disclosure sets forth the relevanthistory of the
development of the U.S. Navy Dive Tables to permit a diver to avoid
DCS and of the computers utilized to implement the use of the
tables.
[0007] The '678 patent discloses a dive computer which utilizes
original mathematical algorithms, assumptions, and calculations
which modify the conservative U.S. Navy Dive Tables to provide
longer underwater dive times for sport divers. The modified tables
and algorithms disclosed in the patent are designed to accommodate
variable dive profiles as compared with Navy divers who work at a
constant depth. The '678 patent is the first to provide a dive
computer which is designed to specifically avoid a decompression
condition by giving the diver the information needed to plan a
dive, maintain a safe air reserve, and dive within the no
decompression limits accepted by the U.S. Navy. However, the
computer includes an emergency decompression scale/guide based on
the Navy tables for divers who get into trouble by descending into
the decompression zone (DZ) as long as they do not exceed 10
minutes therein.
[0008] An improvement in the prior art of SCUBA dive computers as
described in the '678 patent is the Ascent Rate Meter for SCUBA
Divers disclosed in U.S. Pat. No. 5,156,055, issued Oct. 20, 1992,
to Hollis, et al. In order for a diver to control his or her ascent
from depth during a decompression dive into the DZ, they need to
know the ascent rate. The purpose of the '055 invention is to
establish a means for accurately calculating a divers ascent rate
in order that this information can be added to the display of the
dive computers that are used for sport and commercial SCUBA
decompression diving.
[0009] A somewhat parallel development in dive computers for SCUBA
divers is U.S. Pat. No. 5,457,284 for an Interactive Dive Computer,
issued Oct. 10, 1995, to Ferguson. It is described by the inventor,
in the abstract of the patent, as "[A]n interactive apparatus for
use by a SCUBA diver to provide for diver control of a specified
dive-related parameter. The diver enters into the apparatus the
desired parameter value, such as air reserve available at the
completion of the dive, and the apparatus, based on the desired
parameter and current dive conditions, determines the length of
time the diver may remain at the current depth and still safely
ascend to the surface with the desired air reserve. In the
preferred embodiment of the invention, the apparatus also includes
audible and visual alarms to alert the diver to the expiration of
the determined length of safe dive time."
[0010] Specifically, it is stated in the specification of the '284
patent that the reason for the invention is because "[T]here is a
need . . . for an instrument that determines a safe diving or air
reserve period based on both current dive conditions and the
diver's personal safety margin preferences, as well as the diver's
particular physical profile." As a result, it is stated that: "[I]t
is a main object of the invention to provide a dive computer
designed to guide a diver to the surface with a diver specified air
reserve remaining in a compressed air supply at the completion of
the dive." The device is designed to allow a diver to accommodate
his or her safety margin to their specific physiology and personal
preferences based on air time remaining (ATR).
[0011] The present invention is for the same general purpose, which
is to provide SCUBA divers with a computer of which accommodates
different diver physiology and allows him or her to establish diver
selected safety margins, but it achieves the results in a different
way, with different apparatus, and for critically different diving
parameters. The substantial difference between the computers is
that the '284 design is for measuring ATR while the present
invention is based on computing tissue onloading which incorporates
decompression ascent calculations and allows a diver to avoid the
more severe physical punishment of a dive to the limits.
[0012] These two types of diving time measurements are mutually
exclusive for dive computer operation and even though they
necessarily overlap when a diver descends into the DZ. Air time
remaining is not a determining factor unless the diver remains
above the DZ. The '284 patent bases its display solely on air time
remaining which is based on pressure in the air tanks, depth, and
time, measured against a rigid nitrogen onloading scale, although
it is not described, and provides a safety factor by permitting a
preset which triggers an alarm based on a selected air time
remaining safety margin. The present invention provides information
for variable preset safety margins for decompression diving into
the DZ based on nitrogen onloading whereby a less physically
demanding dive profile can be selected than is permitted by the
program of the '284 patent.
[0013] The Ferguson '284 patent permits a diver to select a safety
margin in the dive time remaining (DTR) display in the computer by
providing for an alarm based on an air pressure remaining in the
tank. The algorithm utilized by the 284 patent for DZ diving is
fixed and unalterable by the diver selecting his or her ATR safety
value. The diver must follow the set rigors of the internal program
of the computer and follow the decompression (DECO) profile
thereof. That can often be a harsh regimen for older divers.
[0014] The present invention is concerned with safety margins set
by a diver but measured by different parameters in a different way
with different apparatus. The '284 diver is concerned with arriving
back at the surface with a pre-selected air reserve, but, as
emphasized earlier, air time remaining is not the determining
factor for a diver unless he or she remains above the decompression
zone (DZ). A diver is limited in the DZ by depth and time caused by
tissue onloading, basically of nitrogen, which causes DCS. In order
to ascend from the DZ, a diver must make decompression (DECO) stops
at computed levels during the ascent. The deeper and longer a diver
remains in the DZ, the longer and more numerous the required DECO
stops. The '284 device gives the diver no warning of how the
severity of the DECO regimen for a particular dive is progressing.
The present invention indicates that exact factor and permits a
diver to restrict or limit before hand the severity of the DECO
regimen.
[0015] The present invention is based on a more accurate indicator
of dive time remaining based on tissue nitrogen loading from the
Navy Dive Tables with a multiple of alarms and with a selectable
safety margin for decompression diving. The present invention
allows for diving into the DZ and bases DTR on a modified set of
Navy Dive Tables which in turn can be further modified to conform
with a diver's selected personal safety margins. As a diver grows
older, he or she becomes less capable of enduring the effects of
tissue on loading and DCS, so they prefer to set larger margins of
safety than are provided by computerized calculations of safety
based on the Navy Dive Tables and as modified by various computer
programs. In the present invention, the DZ factor is calculated by
the computer and the diver can select the safety margin based on
the degree of tissue nitrogen onloading.
[0016] The variable setting dive computer contemplated according to
the present invention departs substantially from the conventional
concepts and designs taught by the prior art, and in doing so,
provides an apparatus primarily developed for the purpose of
providing a SCUBA diver with the capability of selecting variable
pre-sets with respect his or her personal physiology during a DZ
dive as described above, but it accomplishes the result in a
different and improved manner, and with new apparatus, for
producing safer diving conditions more accurately, faster, and with
more versatility.
SUMMARY OF THE INVENTION
[0017] In view of the foregoing known, described, and obvious
disadvantages inherent in the known types of dive computers for
SCUBA divers presently existing in the prior art, the present
invention provides a new method of diver condition monitoring for
DZ diving, and a new apparatus and construction for a dive computer
wherein the same can be utilized by divers to pre-select personal
choice variable limits for tissue onloading conditions in the DZ to
avoid DCS.
[0018] The general purpose of the present invention, which will be
described hereafter in greater detail, is to provide a new and
improved dive computer apparatus and method which has many of the
vantages of the prior art of dive computers mentioned and described
above and many novel features and advantages that result in a new
variable limits dive computer which is not anticipated, rendered
obvious, suggested, or even implied by any of the prior art of dive
computers heretofore known, either alone or in any combination
thereof.
[0019] The present invention is a variable limits setting dive
computer for a SCUBA diver which permits establishing variable
diver selected tissue loading limit values for a dive. The
invention comprises at least a minimum of data sensors for said
computer including at least water depth and elapsed time. A
computer means is provided with a software algorithm based on the
Navy Dive Tables for integrating the output from the sensors and
producing a computer output in response thereto. A data display is
provided including a tissue loading bar graph which is actuated by
the output of the computer and indicates when DECO status has been
reached. A selection means is provided which is operable by a diver
to select a value on the tissue loading bar graph for triggering at
least one alarm when the selected value is reached during a dive by
the output from the computer activating the TLBG in response to
having the processor integrate the output from the sensors.
[0020] The more important features of the invention have been
broadly outlined in the preceding summary of the invention in order
that the detailed description thereof which follows may be better
understood and in order that the present contribution to an
improvement in the art may be better appreciated. There are
additional features of the invention that will be described
hereinafter and which will form the subject matter of the claims
appended hereto.
[0021] With respect to the claims hereof, and before describing at
least one preferred embodiment of the invention in detail, it is to
be understood that the invention is not to be limited in its
application to the details of construction and to the arrangements
of the components which are set forth in the following description
or illustrated in the accompanying drawings. The invention is
capable of being created in other embodiments and of being
practiced and carried out in various ways. Also, it is to be
understood that the phraseology and terminology employed here are
for the purpose of description and should not be regarded as
limiting.
[0022] As such, those skilled in the art in which the invention is
based will appreciate that the conception upon which this
disclosure is predicated may readily be utilized as a basis for the
designing of other forms, structures, apparatus, systems, and
methods for carrying out the several purposes of the present
invention. It is important, therefore, that the claims be regarded
as including such equivalent constructions and methods in so far as
they do not depart from the spirit and scope of the present
invention.
[0023] Further, the purpose of the appended abstract is to enable
the United States Patent and Trademark Office, and the public
generally, and especially scientists, engineers and practitioners
of the art who are not familiar with the patent and legal terms or
phraseology, to determine quickly from cursory inspection the
nature and essence of the technical disclosure of the application.
The abstract is neither intended to define the invention of the
specification, which is measured by the claims, nor is it intended
to be limiting as to the scope of the invention in any way.
OBJECTS OF THE INVENTION
[0024] It is therefore an important object of the present invention
to provide a variable limits setting dive computer in which the
nitrogen tissue loading parameter limit is diver selectable.
[0025] It is another object of the present invention to provide a
dive computer with a nitrogen tissue loading bar graph in which a
selectable value thereon automatically activates alarms when it is
reached by the output of the computer.
[0026] It is a further object of the present invention to provide a
dive computer which compensates for dive profiles which vary during
a dive into and out of the DZ to provide a visual representation of
the status of the diver's tissue loading Other objects and
advantages of the present invention will become apparent when the
method and apparatus of the present invention are considered in
conjunction with the accompanying drawings.
DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is an illustration of a dive computer data display as
utilized with and employing the present invention showing the
tissue loading bar graph beginning activation in the green
zone;
[0028] FIG. 2 is an illustration of the data display showing
partial actuation still in the green zone; and
[0029] FIG. 3 is an illustration of the data display showing full
actuation into DECO status.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0030] Reference is made to the drawings for a description of the
preferred embodiment of the variable setting dive computer of the
present invention wherein like reference numbers represent like
elements on corresponding views. FIGS. 1-3 show the data display 11
on the computer control console which is actuated by the output of
the internal computer and which employs the unique tissue loading
bar graph 13 of the present invention.
[0031] The three views of the display console are shown in various
stages of actuation with respect to the tissue loading bar graph
(TLBG) of the present invention. The LCD display face is surrounded
by the cylindrical end of the computer case 15 which has color
indicia imprinted thereon for supplementing the display indicia.
Green colored edging 17 indicates a safe bar graph indication. A
yellow colored edging 19 indicates a warning zone bar graph
indication, and red colored edging 21 indicates a danger zone bar
graph indication.
[0032] A variable colored LCD display could be utilized, but it is
considered too expensive for practical utilization in the present
invention at the present time. However, such embodiments of the
invention are covered by the claims hereof in anticipation of the
time when they can be practically implemented.
[0033] The dive computer of the present invention is very compact
and can be worn on a divers forearm like a wrist watch which is a
convenient viewing orientation for underwater information retrieval
because of most persons normal experience in checking time on a
wrist watch. The display 11 is generally circular and the computer
considerably larger and heavier than a watch, and despite the
larger size and weight, because water displacement lessens the
effect of the weight of the computer on the divers wrist
underwater, the added visibility of the larger visual display
compensates for the minor disadvantages of the large size. The
critical information is displayed in large numbers which can be
read at an extended arms length.
[0034] The variable setting dive computer has an interactive
control console consisting of two control buttons 23, 25 which
allow the user to select display options and access specific
information. They are also used to enter settings, activate the
backlight, and acknowledge the audible alarms. The front button is
referred to as "advance" and the side button as "select."
[0035] There are several bar graphs imposed on the display
including: a tissue loading bar graph (TLBG) 13, oxygen
accumulation bar graph (02BG) 27, a variable ascent rate meter
(VARI) 29. There are also several alpha/numeric and other visual
displays including: a depth display 31, time and date displays 33,
temperature display, LED warning light 37, backlight, power supply
(battery status) indicator, F02 mode, and audible alarms.
[0036] The tissue loading bar graph (TLBG) 13 represents tissue
loading of nitrogen, showing the diver's relative no decompression
or decompression status. As depth and elapsed dive time increase,
segments are added to the graph, and as the diver ascends to
shallower depths, the bar graph will begin to recede, indicating
that additional no decompression time is allowed for multilevel
diving.
[0037] The TLBG 13 is controlled by a custom algorithm derived from
the Navy Dive Tables which monitors 12 different nitrogen
components simultaneously and displays the one that is in control
of the particular dive. An example of such an algorithm is
disclosed in the Hollis '678 patent. Other algorithms which monitor
tissue loading can be utilized with the present invention. The TLBG
is divided into a green "no decompression" (normal) zone 17, a
yellow caution zone (also no decompression) 19, and a red
decompression (danger) zone 21. While a diver cannot be given a
guarantee against the occurrence of DCS by using the graph, he or
she may choose their own personal zone of caution based upon age,
physique, excessive weight, and physical condition to reduce the
statistical risk.
[0038] In addition to the TLBG graph 13, the oxygen accumulation
bar graph (02BG) 27 represents oxygen loading showing the maximum
of either per dive accumulated oxygen or 24-hour period accumulated
oxygen.
[0039] The variable ascent rate indicator (VARI) 29 provides a
visual representation of ascent speed (i.e., an ascent
speedometer). Green color represents a normal rate, yellow a
caution rate, and red indicates too fast.
[0040] The alpha/numeric displays include a depth display 31
showing the depth during the dive. By pressing the advance button
23, the maximum depth reached the during a dive will be displayed
in the center/left portion of the display. During a decompression
dive, the required "ceiling stop depth" is displayed in the center
the screen.
[0041] The time displays are shown in the hour and minute format.
The colon that separates the hours and minutes blinks once per
second when the display is indicating real-time (e.g., elapsed dive
time), and is solid (non-blinking) when times are calculated
projections (e.g., time to fly). The main time display is located
in the lower portion of the display and a second time display is
located in the center/right. Both displays are identified by a
clock icon. Date is displayed in the center left portion of the
screen only to identify dive data when it is viewed in the log
mode.
[0042] Ambient temperature is displayed in the center/left portion
of the screen while the computer is in the surface mode and log
mode and can be viewed as part of an alternate display when the
advance button is pressed while in a dive mode.
[0043] A red LED warning light 37 and speaker icon are synchronized
with the audible alarm and will illuminate the display when the
alarm emits a tone. They will turn off when the alarm is
acknowledged or set to off (a user setting). When warning
situations activate the alarm, the unit will emit a continuous tone
for 30 seconds, or until the situation is corrected, or it is
acknowledged by pressing the advance button for two seconds. The
audible and LED alarms can also be set for activation under other
conditions.
[0044] The backlight can be activated by pressing the side button
25. The battery power supply includes an indicator in the lower
left corner of the display which is displayed when power is
sufficient for normal unit operation and is not displayed during
dive modes.
[0045] The dive computer will operate as an air computer without
displaying information associated with oxygen calculations (F02
mode) unless it is set for a percentage of oxygen other than air in
which case it will operate as a gas calculator.
[0046] The variable setting dive computer of the present invention
is designed for SCUBA divers and permits the establishment of
variable diver selected tissue loading limit values for a dive. In
order for a dive computer to utilize the method of the present
invention, it must include apparatus which is comprised of data
sensors for the computer which include at least a water depth
sensor (ambient hydrostatic pressure) and an elapsed time timer. In
order to perform the full function of a state-of-the-art dive
computer, such as described in the Hollis 678 patent, the device
also requires air tank high and low pressure transducers, breathing
rate sensor, ascent rate sensor (such as described in the Hollis et
al. '055 patent), and temperature sensor.
[0047] The tissue loading bar graph (TLBG) 13 of the present
invention is a visual display in the form of a progressively
changing pictorial representation. There are numerous forms for a
bar graph representation such as: a series of aligned blocks which
change color or shape; an elongating bar either straight or curved:
a series of objects which progressively appear and disappear, or
are progressively illuminated or interconnected and the reverse;
and any combination of these representations and many others. In a
more sophisticated LCD bar graph, it could change color as it
advances and retreats. All types of bar graphs can be utilized for
the TLBG of the present invention and are considered to be included
in the term TLBG.
[0048] The preferred embodiment of the present invention utilizes a
particular format for the TLBG 13 which is believed to be
particularly adapted for the purposes of the present invention. A
series of circles are provided disposed around a portion of the
periphery of the computer display preferably at the top left
thereof in the prominent display position for persons reading from
left to right. The circles are located in the 9-12 o'clock quadrant
and progress in size in two dimensions as the TLBG increases to
denote increasing tissue loading: they increase in size in both
diameter and wall thickness. The smaller size circles are located
at the lower end of the graph or scale and increase in dimensions
with the nitrogen onloading. The circles increase in wall thickness
to effect a larger presence as each circle appears on the
display.
[0049] FIG. 1 of the drawings shows the TLBG as it would be
initially activated early in a dive. The smaller circles would
appear alongside the green zone of the indicia on the computer
case. FIG. 2 of the drawings shows the circles 39 which appear
during a dive just before a diver enters a yellow caution zone due
to a combination of his depth and duration underwater at variable
depths as computed by the algorithm in the computer. FIG. 3 of the
drawings shows the diver's condition represented by the circles 41
when he enters a decomposition (DECO) status denoted by the red
indicia on the computer case. The DECO warning is illuminated and
remains so until the diver goes through the DECO procedures in
which case the TLBG will start to decrease.
[0050] A computer means such as described in the Hollis '678 patent
is provided for integrating the output from the sensors according
to an algorithm based on the Navy Dive Tables. The computer intakes
the output from the various sensors and integrates it into various
forms of information which are transmitted as computer output to
the various data displays on the computer console. The only
essential sensors for measuring tissue loading are the water depth
transducer and elapsed time timer.
[0051] A selection means is provided which is operable by a diver
to select the value on the tissue loading bar graph for triggering
at least one alarm when the preset value is reached during a dive
by the output from the computer in response to integrating the
output from the sensors. The alarms include an audible tone and a
red LED warning light which illuminates on the display face above
the top end of the TLBG. Both alarms are usually activated
simultaneously.
[0052] There are eight segments or circles in the tissue loading
bar graph, in the preferred embodiment of the present invention,
although more or less would serve the purpose. The circles extend
for approximately a quarter of the periphery of the display face,
or approximately 90 degrees, comparable to-from 9 o'clock to 12
o'clock on a watch face. The last segment is not a circle. It is a
segment with the DECO warning printed thereon which appears when
DECO is reached. The circles appear (and disappear) one by one
progressively on the display as the tissue loading occurs or abates
until (in the factory setting) the DECO segment appears and the LED
and audible warning signals are activated.
[0053] However, it is the purpose of the present invention that any
one of the circles can be selected as the target value for
activating the alarms. The computer is factory set for activating
the alarms at DECO or when all eight segments have appeared on the
TLBG. The alarm to indicate maximum acceptable tissue loading can
be set to values between DECO (all eight segments) and a single
segment. This is done during pre-dive setting of the computer while
in the surface mode. By a combination of actuation of the advance
and select buttons 23, 25, a selected warning segment of the TLBG
can be accepted as the warning segment for activating the alarms.
The alarm setting based on the segments can be increased or
decreased by actuation of the control buttons on the computer.
[0054] In the preferred embodiment of the invention, the selection
of the TLBG segment which will activate the alarms is set by
pressing both buttons, advance 23 and select 25, simultaneously.
Then the advance (front) button is actuated and the units of the
TLBG all appear with a set point flashing (appearing and
disappearing). After the set point is flashing by the press and
release of the advance button, that button is pressed eight more
times. The graphic ndc and alarm (speaker) icon appear with the
full TLBG flashing. Then the side button is pressed and released to
decrease the number of segments individually one at the time. When
the desired alarm setting is reached on the TLBG, the advance
button is pressed to accept the setting and advance computer face
to the set dive time remaining alarm or both buttons can be pressed
for two seconds to revert to surface mode.
[0055] The advantage of the present invention is that a diver can
select from experience, or out of caution, a lower-level of tissue
loading as a dive warning limit before he goes underwater. The
selectable value is directly associated with the dive parameter
which is most critical to a diver for avoiding DCS. None of prior
devices provide this versatility in dive planning.
[0056] Thus, it will be apparent from the foregoing description of
the invention in its preferred form that it will fulfill all the
objects and advantages attributable thereto. While it is
illustrated and described in considerable detail herein, the
invention is not to be limited to such details as have been set
forth except as may be necessitated by the appended claims.
* * * * *