Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02255092 1998-11-30
AVALANCHE TRANSCEIVER
Background of the Invention
Rescue devices have been used by persons who are
active in areas subject to avalanches. These devices
typically may be employed either in a transmit mode or a
receive mode. The device is normally carried or worn by
the user while active in the transmit mode, where the
device transmits a modulated electromagnetic signal at a
specified frequency. If the user is buried by an
avalanche, a rescuer using a similar device in the
receive mode can detect the transmitted signal and use
the signal to locate the buried person.
Such avalanche rescue devices typically have a
variety of common elements. They have a transmitter
which generates a pulsed electromagnetic signal at a
specified frequency. An antenna is provided which serves
to transmit the pulsed electromagnetic signals when they
are being generated.
These avalanche rescue devices also have a receiver
which, in combination with the antenna, is designed to
receive signals being transmitted by another rescue
device operating in the transmit mode. The transmitter,
antenna, receiver, and a battery pack which serves as a
power source, are packaged in a case and provide a
compact unit which can be readily worn or carried. When
worn, a harness constructed from one or more belts is
provided for securing the case to a person. The harness
in turn attaches to the case with a first belt connector
and a second belt connector.
For safety reasons, it is desirable to design the
rescue device such that it is difficult for the user to
inadvertently carry the device with the power off or in
the receive mode. If the device is not active in the
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transmit mode when the user is buried by an avalanche,
rescuers may be unable to locate the user. One prior art
rescue device which offers a high degree of safety is the
F1 Focus avalanche transceiver device designed by the
present inventor. The F1 Focus offers several features
which reduce the likelihood of the device being worn or
carried while not active in the transmit mode.
The F1 Focus device has an antenna, a
transmitter/receiver circuit, and a battery which are
housed in a case. The case is designed to be worn by the
user, and when in use is attached to the user by a
harness made up of belts. The belts connect to the case
via a first belt connector and a second belt connector.
The first belt connector is detachable from the case,
while the second belt connector is permanently attached
to the case.
The first belt connector has a T-shaped protrusion
which is designed to fit into a receptor slot on the
case. To connect the first belt connector to the case,
the T-shaped protrusion is placed into the receptor slot
and rotated to lock the T-shaped protrusion therein and
secure the device to the user.
To assure that the device is active when secured to
the user, the first belt connector is configured to
operate a power switch which activates and deactivates
the device. Insertion of the T-shaped protrusion into
the receptor slot moves the power switch to a position
where it completes a circuit between the battery and the
transmitter/receiver circuit to activate the device.
Turning and removing the T-shaped protrusion from the
receptor slot allows the power switch to return to a
position where the circuit is broken, and the device is
inactive. While the interaction of the first belt
connector and the power switch provides increased safety
for the user, the requirement that the belts be attached
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to the case in use may be inconvenient when the user
desires to carry the device in a pocket or pouch.
The device has a transmission status light on one
side of the case. The transmission status light is
positioned such that the user may wear the device with
the transmission status light readily visible. The
transmission status light is illuminated when the device
is active in the transmit mode, providing notice of such
to the user.
The device also has a combination mode/sensitivity
switch which allows the user to manually switch the
device between its transmit and receive modes, and, when
the device is in the receive mode, allows the user to
adjust the sensitivity of the receiver. The
mode/sensitivity switch is a rotary switch having a
transmit position, where the transmitter is active, and a
number of receive positions in which the receiver is
active. The different receive positions correspond to
decreasing levels of sensitivity of the receiver when
detecting a transmitted signal.
The mode/sensitivity switch also has a transmit lock
device. When the mode/sensitivity switch is in the
transmit position, the transmit lock device prevents the
user from turning the mode/sensitivity switch unless the
transmit lock device is first manually retracted. The
transmit lock device thus helps prevent the user from
inadvertently turning the device from the transmit mode
to the receive mode. The mode/sensitivity switch may be
freely turned from any of the receive positions to the
transmit position.
When being used in the receive mode to locate a
buried person, the user initially turns the
mode/sensitivity switch to the highest sensitivity
position. In this position, the response of the receiver
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to a transmitted signal received via the antenna is
greatest. If no signal is detected, the user is trained
to execute a broad search pattern until a signal is
found. When a signal is detected, a speaker provides an
audio output, the volume of which is proportional to the
response of the receiver. As the searcher approaches the
buried person along a field line of the transmitted
signal, the strength of the signal received increases,
and the response of the receiver correspondingly
increases.
While most avalanche rescue devices provide an audio
output, the F1 Focus additionally features three signal
strength indicator lights. These signal strength
indicator lights are progressively illuminated as the
response of the receiver increases. When the response of
the receiver is sufficiently great that the audio output
of the speaker is very loud and all three signal strength
indicator lights are illuminated, the user turns the
mode/sensitivity switch to the next receive position,
where the response of the receiver to a given signal
strength is reduced. This procedure is repeated until
the least sensitive receive position of the
mode/sensitivity switch is used. In this position, when
the response of the receiver is sufficiently great that
the audio output of the speaker is very loud and all
three signal strength indicator lights are illuminated,
the user is trained to execute a pinpoint search to
determine the location of the buried person with a high
degree of precision, and then digs down to uncover the
buried person.
While the volume of the audio output and the three
signal strength indicator lights provide the user an
indication of the strength of the signal being received,
this may or may not correspond to the distance to the
buried person. If the signal is to continuously
increase, the searcher must follow a curved field line to
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reach the buried person, rather than taking a straight
path. Increased precision in the indication of signal
strength helps provide notice to the user when they have
moved off of the field line they are following and thus
5 helps the user to effectively reach the buried person.
In an attempt to provide the user increased
precision in indicating an estimated distance to the
buried person, a device having a pair of antennas has
been employed. However, this device requires complicated
circuitry to estimate the distance from the relative
signal strengths received from each antenna, rather than
simply measuring signal strength along a field line with
a single antenna. The device then presents the distance
on a digital display. Such dual antenna devices have
been found to be sensitive to orientation, and may
provide signal strength differences of 5:1 for differing
orientations at the same distance.
A concern with all such rescue devices is the
training required for their effective use. Speed in
locating and uncovering the buried person is of primary
importance in rescue situations, and any hesitation on
the part of the rescuer may reduce the chance of survival
of the buried person. Additionally, witnessing an
avalanche is traumatic, and may impair the ability of the
searcher to remember what appropriate actions to take.
An additional concern when multiple searchers are
employed is the possibility that one or more of the
searchers may inadvertently have their rescue device in
the transmit mode. This may interfere with the other
searchers receiving signals from the buried person.
Thus, there is a need for a rescue device which does
not require the belts to be attached for use, which
provides increased precision in indicating signal
strength to the user, and which is readily operated with
minimal training and/or under traumatic conditions.
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Objects of the Invention
It is an object of the present invention to provide
an avalanche transceiver which prompts the user to
perform appropriate search actions.
It is an object of the present invention to provide
an avalanche transceiver which prompts the user when to
switch the sensitivity to a more appropriate range.
It is an object of the present invention to provide
an avalanche transceiver which indicates to the user when
the transceiver is moved away from orientation along an
induction line transmitted by a buried transmitter.
It is an object of the present invention to provide
an avalanche transceiver which provides the user a visual
indication of the distance along the induction line to
the buried transmitter.
It is an object of the present invention to provide
an avalanche transceiver which uses a bar graph to
indicate the strength of a signal received with a high
degree of resolution.
It is an object of the present invention to provide
an avalanche transceiver which is automatically turned on
and placed in a transmit mode when strapped to the user.
It is an object of the present invention to provide
an avalanche transceiver which cannot be turned off while
it is strapped to the user.
It is an object of the present invention to provide
an avalanche transceiver which can be turned on without
requiring a strap being attached thereto.
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It is an object of the present invention to provide
an avalanche transceiver which requires deliberate action
to be turned off.
It is an object of the present invention to provide
an avalanche transceiver which is automatically placed
into a receive mode when removed from being strapped to
the user.
It is an object of the present invention to provide
an avalanche transceiver which assists multiple
transceiver users in determining whether all users have
switched their transceivers to a receive mode.
It is an object of the present invention to provide
an avalanche transceiver which may remain connected to
the user when placed into its receive mode.
It is an object of the present invention to provide
an avalanche transceiver which can be readily switched
from its receive mode to its transmit mode when not
strapped to the user.
It is an object of the present invention to provide
an avalanche transceiver which requires deliberate action
to be switched from its transmit mode to its receive mode
when not strapped to the user.
It is an object of the present invention to provide
an avalanche transceiver having a transmit indicator
which is activated when the transceiver is active in its
transmit mode, the transmit indicator being positioned to
be readily seen by the user when the transceiver is worn
in alternative positions.
It is an object of the present invention to provide
an avalanche transceiver which employs an LCD display to
provide information to the user.
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It is an object of the present invention to provide
an avalanche transceiver which stores the highest signal
amplitude value received, and warns the user when the
current signal amplitude drops below a certain percentage
of the stored signal amplitude value.
It is an object of the present invention to provide
an avalanche transceiver which automatically updates the
stored signal amplitude value when a higher signal
amplitude is received.
It is an object of the present invention to provide
an avalanche transceiver which has a curved case to
comfortably fit against the body, with the controls and
display of the transceiver facing the user's body for
protection and warmth.
It is an object of the present invention to provide
an avalanche transceiver which may be readily operated
with one hand.
It is an object of the present invention to provide
an avalanche transceiver which may be operated to
distinguish one of multiple received signals.
It is an object of the present invention to provide
an avalanche transceiver which provides an indication of
the state of charge of its batteries.
Suumiary of the Invention
The present invention is an improved rescue device
for locating persons buried by an avalanche. The
improvements are well suited to dual-purpose avalanche
rescue devices which operate in either a transmit mode or
a receive mode as discussed above in the Background of
the Invention.
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One aspect of the improvement of the present
invention resides in a harness connector system for
fastening belts to the case which houses the rescue
device. The rescue device of the present invention has a
first belt terminator which serves as the first belt
connector. The first belt terminator is shaped to
lockably engage a first belt terminator receptor which
forms part of the case and may be an integral part
thereof or attached thereto.
A power switch assembly is associated with the first
belt terminator receptor. The power switch assembly has
a power switch with a power on position and a power off
position, as well as means for switching from the power
on position to the power off position which are
responsive to the engagement and disengagement of the
first belt terminator with the first belt terminator
receptor. When the power switch is in the power on
position, power is available to both the transmitter and
the receiver.
Means for releasing the first belt terminator from
the first belt terminator receptor are provided.
Preferably, the means for releasing the first belt
terminator are configured such that neither a compressive
load or shear load on the case will activate the release.
One preferred means for release is a lift and turn
locking mechanism.
It is further preferred that the means for power
switching have a complementary means for mechanical
activation which is independent of the first belt
terminator. It is further preferred that the two means
act in a cooperative manner providing a dual activated
power on/off system. This dual activated power on/off
system, while part of the harness connector system, is
felt to have utility which extends beyond the harness
connector system of the present invention.
CA 02255092 1998-11-30
The rescue device of the present invention has a
second belt terminator which serves the second belt
connector. A second belt terminator receptor is also
provided which forms part of the case and may be an
5 integral part thereof or attached thereto. The second
belt terminator is shaped to lockably engage the second
belt terminator receptor.
The rescue device of the present invention also has
10 a mode switch which is associated with the second belt
terminator receptor. The mode switch has a transmit mode
position and a receive mode position. Means for toggling
the mode switch to the transmit mode when the second belt
terminator is engaged with the second belt terminator
receptor and to the receive mode when the second belt
terminator is not engaged with the second belt terminator
receptor are provided.
The mode switch is preferably biassed to the receive
mode position by a biassing means and the second belt
terminator is configured such that, in addition to
lockably engaging the second belt terminator receptor,
the second belt terminator toggles the mode switch to the
transmit mode position when so engaged.
Means for locking and releasing the second belt
terminator are provided. Preferably, the means for
locking and releasing the second belt terminator are
configured such that neither a compressive load nor a
shear load on the case will activate the release.
Preferably, supplemental means for toggling the mode
switch are provided which are independent of the
interaction between the second belt terminator and the
second belt terminator receptor. Means for releasing the
supplemental means for toggling the mode switch are
provided which are preferably shared with the means for
releasing the second belt terminator. This dual-
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activatable toggling mechanism is felt to have utility
which extends beyond the harness connector system of the
present invention.
The case of the present invention also contains
additional features which form part of the preferred
embodiments of the present invention. It is preferred
that the case be configured such that it can be readily
held in one hand. It is also preferred that the case
have a top surface which is concave to conform to the
body of the wearer. A LCD display is preferably provided
on the concave top surface. Making the top surface
concave encourages the wearer to maintain this surface
next their body, providing both mechanical and thermal
protection to the LCD display. It also preferred that a
dial for changing the stage of a multistage amplifier of
the rescue device be configured to allow the user to
readily operate the dial with the same hand which holds
the case. Transmission status lights are preferably
provided on the sides of the rescue device so that, when
the rescue device is worn by the user, the user can
readily see whether the rescue device is powered and in
the transmit mode.
The above described harness connector system and
associated case has utility in and of itself, or may be
combined with the following aspect of the invention,
which relates to an on-board signal processing system for
processing the signals being generated by a rescue device
in the transmit mode and being received by the rescue
device of the present invention. This signal processing
system generates a visual display as part of its output,
and presents information in graphic form which helps
expedite the search process, including icons which prompt
the searcher as to how to advance the search.
Similar to prior art rescue devices, the signal
processing system includes a signal pre-processor which
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receives an antenna signal from the antenna of the
searcher's rescue device, this signal being generated by
the rescue device of the buried party. The signal pre-
processor converts the antenna signal to an audio
frequency signal. The audio frequency signal is
processed through the multistage amplifier to provide a
working signal with enhanced sensitivity of the audio
output. The working signal is presented over a speaker.
The signal processing system of the present
invention provides a means for sensing the stage in which
the multistage amplifier is operating and providing a
stage signal. The signal processing system further
processes the working signal, and in some instances the
input signal, in combination with the stage signal to
provide prompts and other visual information to assist a
rescuer in searching effectively. The signal processing
system provides a variety of functions which assist the
searcher. Preferably, there is a working signal
interface pre-processor to make the working signal
compatible with subsequent circuitry and microprocessors
which are employed in the signal processing system when
such signal conditioning is required.
The signal processing system is provided with means
for determining whether a coarse search or a pin-point
search should be conducted and causing an appropriate
icon to be presented on the visual display when such a
condition is met. Means are also provided to determine
whether there is a need to change the stage of the
multistage amplifier and, when the amplifier is about to
saturate or provide an infinitesimal signal, to provide a
notice to change the stage to a stage of greater or
lesser sensitivity by turning the dial on the rescue
device either up or down. Hereinafter, switching to an
increased sensitivity position is defined as switching
"up", and switching to a reduced sensitivity position is
defined as switching "down". The signal processing
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system is also provided with means for providing notice
as to when the rescue device needs to be reoriented to
provide the maximum strength signal from the buried
party. This means provides an appropriate icon when such
occurs.
Preferably, the signal processing system also
provides means for displaying the strength of the signal
from the multistage amplifier as a bar graph. It is
further preferred that the bar graph be framed in an icon
shaped as an arrow. It is also preferred that the signal
processing system have means for analyzing one of the
signals generated by the receiver and converting the
strength of the signal to an estimated distance to the
buried transmitter, and displaying the distance on the
visual display.
All of the above means are readily implementable
either by circuitry or by use of appropriate interfaces
and one or more microprocessors programmed with
appropriate instruction sets.
Brief Description of the Figures
Figure 1 is an isometric view of an improved rescue
device which forms one embodiment of the present
invention. The device has a case having a top surface.
A viewing screen for display of information and a dial
for adjusting the sensitivity of the device are provided
on the top surface, and the case is designed to allow
operation with a single hand. The device is attached to
the user by a harness which is attached to the case by a
first belt terminator and a second belt terminator. The
first belt terminator engages a first belt terminator
receptor on the case and controls whether power is
provided to the device. The second belt terminator
engages a second belt terminator receptor on the case and
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toggles the device between a transmit mode and a receive
mode.
Figure 2 is an exploded isometric view of one
embodiment of a first belt terminator and an associated
first belt terminator receptor which may be employed in
the device shown in Figure 1. In this embodiment, a
power switch is biassed by a torsion spring to a power-
off position. The first belt terminator engages the
power switch to turn it to a power-on position. A
spring-biassed first terminator latch is provided for
lockably engaging the first belt terminator with the
first belt terminator receptor.
Figure 3 is a view showing a first terminator
release tab which is pivotably mounted to a case and
which, when lifted, releases the first terminator latch
shown in Figure 2.
Figure 4 is an exploded isometric view of another
embodiment of a first belt terminator and an associated
first belt terminator receptor, which differs from the
embodiment illustrated in Figures 2 and 3 in that it
allows the user to manually switch the power on and off.
Figure 5 is a view showing a first terminator
release tab which may be grasped by the user to turn the
rotatable switch plate shown in Figure 4, as well as to
release a first terminator latch.
Figure 6 is a detail view of the power switch of the
embodiment shown in Figures 4 and 5.
Figure 7 is a partially exploded isometric view
showing another embodiment of a first belt terminator and
an associated first receptor, which function similarly to
the embodiment shown in Figures 4-6, but which employ a
simplified structure for locking the first belt
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terminator in the first receptor. This embodiment also
employs a spring-loaded flap to cover the first receptor
to prevent snow from entering. The latch assembly has a
pair of locking catches which engage probes on the first
5 belt terminator. A pivotably mounted first terminator
tab serves to move the latch assembly to allow the probes
to be withdrawn.
Figure 8 is a an exploded isometric view
10 illustrating a second belt terminator and an associated
second belt terminator receptor which may be employed in
the device shown in Figure 1. A mode switch is biassed
such that the device is in the receive mode when the
second belt terminator is not engaged with the second
15 belt terminator receptor. The second belt terminator has
a terminator arm which is inserted into the second belt
terminator receptor and which moves the mode switch to
the transmit mode.
Figure 9 is a partially exploded isometric view of a
second belt terminator and a second belt terminator
receptor which may be employed in the device shown in
Figure 1 to allow the rescue device to be placed in the
transmit mode either by inserting the second belt
terminator into the second belt terminator receptor or by
manually operating a mode switch.
Figure 10 is a partially exploded view showing an
alternative second belt terminator and associated second
belt terminator receptor which function similarly to
those shown in Figure 9. In this embodiment, spring-
loaded flaps are provided to cover the second belt
terminator receptor.
Figure 11 is a view showing the second belt
terminator and second belt terminator receptor of Figure
10 where the second belt terminator has been inserted
into the second belt terminator receptor.
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Figure 12 is an isometric view showing another
improved rescue device which employs a preferred harness
arrangement for attaching a case to the user. Again, the
case is attached via a first belt terminator, which
controls the power to the device, and a second belt
terminator which toggles the device between a transmit
mode and a receive mode. The device has both a waist
belt and a shoulder belt, which are connected together.
Figure 13 shows the rescue device of Figure 12 where
the second belt terminator has been detached from the
case, in order to switch the device from the transmit
mode to the receive mode. The shoulder strap continues
to attach the case to the user while allowing the user to
readily hold the case to operate the device to conduct a
search.
Figure 14 is a schematic illustration of an on-board
rescue analysis system of the present invention. The
rescue analysis system receives a signal and processes it
using a multistage amplifier. The rescue analysis system
has a sub-system for operating on the processed signal to
provide direction to the user in conducting a search.
Figures 15 through 19 show icons which may be
displayed by the rescue analysis system shown in Figure
14. The icons serve as prompts to indicate to the user
what action should be taken to conduct a search.
Figure 20 is a schematic illustration of one
embodiment of an on-board rescue analysis system of the
present invention. The rescue analysis system receives a
signal and processes it using a multistage amplifier.
The processed signal is provided to a microprocessor, and
an amplifier level sensor provides a stage level signal
to the microprocessor which indicates which stage of the
amplifier is selected. The microprocessor operates on
the processed signal and the stage level signal and
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directs a display driver which drives a display to prompt
the user to take appropriate search actions.
Figure 21 is an isometric view which illustrates the
on-board rescue analysis system shown in Figure 20 housed
in a case, where the display is a liquid crystal display
mounted in a front face of the case. The speaker and a
dial for manually operating the multistage amplifier are
also mounted in the front face.
Figure 22 is a flow diagram illustrating the
operation of the rescue analysis system shown in Figure
20. The microprocessor has instruction sets for several
routines, which direct the display driver to generate and
send icons to the display according to certain conditions
of the processed signal strength and the stage of the
multistage amplifier which is selected.
Best Mode of Carrying the Invention into Practice
Figure 1 is an isometric view of an improved rescue
device 100 which includes a transmitter, an antenna, and
a receiver (these internal elements are not shown) which
are housed in a case 102. The case 102 is substantially
shaped as a rectangular parallelepiped having a top
surface 104 and a bottom surface 106 which form the bases
of the parallelepiped. A viewing screen 108 for display
of information to assist in locating a buried party is
provided. The rescue device 100 also has a dial 110 for
adjusting the sensitivity of the rescue device 100. A
speaker 112 provides a complementary audio signal used in
locating the buried party. A headphone jack 113 is
preferably provided to allow a headphone to optionally
replace the speaker 112. One or more display lights 114
are preferably provided, which provide information on the
status of the search.
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The case 102 of the rescue device 100 is preferably
configured so as to be readily held and operated with a
single hand. To facilitate such single-handed operation,
it is preferred that the case have a width W not greater
than about 7 cm. It is also preferred that the viewing
screen 108, the dial 110, the speaker 112, and the
display lights 114 be mounted on the top surface 104 of
the case 102 so that they may be readily viewed and
accessed when the rescue device is being operated single-
handed. It is also preferred for the dial 110 to have a
thumb recess 116 which can be used to adjust the dial 110
when being operated in a single-handed manner. A raised
ridge 118 is also provided so as to facilitate turning
the dial 110 with a second hand when the operator wishes
to operate the rescue device 100 in a two handed manner.
The rescue device 100 is designed to be worn by
parties who are in an avalanche sensitive area, and is
maintained in position on the user by a harness which can
be fashioned from belts 120. The belts 120 are attached
to the case 102 by a first belt terminator 122 and a
second belt terminator 124.
The first belt terminator 122 engages a first belt
terminator receptor 126 which forms part of the case 102
and resides in a first harness support end 128 of the
case 102. The first belt terminator 122, when inserted
in the first belt terminator receptor 126, is lockably
engaged therein and, when so inserted, assures that power
is available to the transmitter and the receiver.
The second belt terminator 124 engages a second belt
terminator receptor 130 which forms part of the case 102
and resides in a second harness support end 132 of the
case 102. When the second belt terminator 124 is
inserted in the second belt terminator receptor 130, the
second belt terminator 124 is lockably engaged therein
and, when so engaged, toggles a mode switch 134 to a
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transmit mode, where the transmitter receives power.
It is preferred that the case 102 be configured with
the top surface 104 being slightly concave, to encourage
the person wearing the case 102 to place the top surface
104 against their body to provide protection and a degree
of warmth to the viewing screen 108, the speaker 112, and
the display lights 114 when such are located on the top
surface 104. It is also preferred that the case 102 have
side panels 136 which have transmission status lights 138
therein, which are illuminated when the transmitter is
receiving power, providing notice to the user that the
rescue device which has been strapped on is in the
transmit mode.
Figure 2 is an exploded isometric view of one
embodiment of a first belt terminator 200 and an
associated first belt terminator receptor 202 which are
designed to cooperate as discussed above providing power
furnished by a battery 204 to a transmitter and receiver
assembly 206. Power is supplied to the transmitter and
receiver assembly 206 by a power switch 208 which is
positioned with respect to the first belt terminator
receptor 202 such that the power switch 208 is in a power
off position as illustrated when the first belt
terminator 200 is disconnected from the first belt
terminator receptor 202.
In this embodiment, the power switch 208 has a power
switch body 210 with a post 212 which serves as a first
switch advancing surface. The first belt terminator 200
has terminator prongs 214 which are configured to engage
receptor tracks 216 along which the terminator prongs 214
advance when the first belt terminator 200 is placed into
the first belt terminator receptor 202. A probe 218
having a probe surface 220 is positioned on one of the
terminator prongs 214 such that the probe surface 220
engages the post 212 as the first belt terminator 200 is
CA 02255092 1998-11-30
engaged with the first belt terminator receptor 202. As
the probe surface 220 advances, it rotates the power
switch body 210 about a power switch axis 222 and against
the bias of a power switch torsion spring 224. This
5 rotation of the power switch body 210 rotates a contact
surface 240 on the power switch body 210 such that the
contact surface 240 provides a conductive path between
power contacts 246, completing a circuit 248 between the
battery 204 and the transmitter and receiver assembly 206
10 and thus placing the power switch 208 in a power-on
position.
To lockably engage the first belt terminator 200
with the first belt terminator receptor 202, a first
15 terminator latch 250 is provided. The first terminator
latch 250 is configured to slidably engage the first belt
terminator 200 as it is advanced into the first belt
terminator receptor 202. The first terminator latch 250
is mounted on a leaf spring 252 having a leaf spring
20 fixed end 254 which is fixed with respect to the receptor
tracts 216. The leaf spring 252 is configured to apply a
bias to the first terminator latch 250 as it is advanced
along the first belt terminator 200, this bias sufficing
to promote engagement of the first terminator latch 250
when it is advanced over a first terminator latch groove
256 in the first belt terminator 200.
To release the first belt terminator 200, the first
terminator latch 250 is disengaged from the first
terminator latch groove 256 by a first terminator release
tab 258. As shown in Figure 3, the first terminator
release tab 258 is mounted with respect to a case 260 so
as to be pivotable about a tab axis 262. The first
terminator release tab 258 is configured such that it
resides flush in a bottom surface 264 of the case 260
when the first belt terminator 200 is lockably engaged
and held in position by the engagement of the first
terminator latch 250 with the first terminator latch
CA 02255092 1998-11-30
21
groove 256. The first terminator release tab 258 is
pivoted by the user about the tab axis 262 by lifting a
tab lift end 266 (shown in Figure 2). Lifting the tab
lift end 266 causes a tab spring engaging end 270 to be
depressed, depressing the leaf spring 252 so as to remove
the first terminator latch 250 from engagement with the
first terminator latch groove 256. The disengagement of
the first terminator latch 250 from the first terminator
latch groove 256 allows the first belt terminator 200 to
be withdrawn from the first belt terminator receptor 202.
When the first belt terminator 200 is withdrawn, the
power switch torsion spring 224 is free to rotate the
contact surface 240 out of contact with the power
contacts 246, thus breaking the circuit 248 and
eliminating power to the transmitter and receiver
assembly 206.
Figure 4 is an exploded isometric view of another
embodiment of a first belt terminator 300 and an
associated first belt terminator receptor 302. This
embodiment differs from the embodiment illustrated in
Figures 2 and 3 in that it provides a dual activated
power on/off system that has the utility in rescue
devices not encompassing all the remaining features set
forth in the present application. The dual action power
on/off system includes a rotatable switch plate 304 which
is mounted in a surface 306 of a case 308 and preferably
the bottom surface (best illustrated in Figure 5). A
first terminator tab 310 having a tab lift end 312 is
pivotably mounted on the rotatable switch plate 304 such
that, when the tab lift end 312 is lifted, the first
terminator tab 310 provides a substantially vertical
surface which can be used to manually rotate the
rotatable switch plate 304 from a power-off position to a
power-on position.
The rotatable switch plate 304 has a stem 314 which
slidably but not rotatably engages a power switch body
CA 02255092 1998-11-30
22
316. Followers 318 which are resiliently mounted with
respect to the case 308 ride in switch tracks 320 which
terminate in locking depressions 322, thus limiting
rotation of the power switch body 316 and providing
retention in two positions.
Figure 4 illustrates the power switch body 316 in
the power-off position. A battery 324 which serves as a
power supply for a transmitter and receiver assembly 326
through a power circuit 328 is not able to deliver power,
since a pair of power circuit contacts 330 are biassed to
an open position.
Figure 6 illustrates the power switch body 316 in
the power-on position. In this position, the circuit
contacts 330 are closed to complete the power circuit 328
and allow the battery 324 to power the transmitter and
receiver assembly 326. The circuit contacts 330 are
brought into contact with each other by a contact cam
surface 332 mounted on the power switch body 316 as the
rotatable switch plate 304 and the power switch body 316
are rotated from the power-off position to the power-on
position.
The above described switch can be manually operated
by using the first terminator tab 310 to rotate the
rotatable switch plate 304, without requiring the first
belt terminator 300 being inserted in the first belt
terminator receptor 302.
While the rotatable switch plate 304 can be used to
turn on or off the power to the transmitter and receiver
assembly 326, the power is also controlled by the
insertion of the first belt terminator 300 into the first
belt terminator receptor 302 and the removal therefrom.
In the embodiment shown in Figure 4, the first belt
terminator 300 has a top side 334 and a bottom side 336
CA 02255092 1998-11-30
23
which are symmetrically designed such that the first belt
terminator 300 is symmetric with respect to the top side
334 and the bottom side 336, allowing the first belt
terminator 300 to be inserted into the first belt
terminator receptor 302 with either the top side 334 up
or the bottom side 336 up.
The first belt terminator 300 has a pair of probes
338 each having a probe engaging surface 340. Depending
on the orientation of the first belt terminator 300, one
of the probe engaging surfaces 340 is positioned to
engage an advancing post 342 mounted on the power switch
body 316 as the first belt terminator 300 is advanced
along receptor tracks 344. The advancing post 342 serves
as a first switch advancing surface. As the first belt
terminator 300 continues to be inserted, the engagement
of the probe engaging surface 340 with the advancing post
342 rotates the power switch body 316 from the power-off
position to the power-on position.
It should be noted that, when the first belt
terminator 300 is fully inserted into the first belt
terminator receptor 302, the engagement of the advancing
post 342 with the probe engaging surface 340 prevents the
power switch body 316 from being rotated to the power-off
position. This provides additional safety for the user,
since it prevents the power from being accidentally
turned off while the case 308 is connected to the user.
The pair of probes 338 also each have a power
disengaging surface 346. Depending on the orientation of
the first belt terminator 300, one of the power
disengaging surfaces 346 is positioned to engage a return
post 348 mounted in the power switch body 316 as the
first belt terminator 300 is withdrawn from the first
belt terminator receptor 302. The return post 348 serves
as a first switch return surface. It should be noted
that the rotation of the power switch body 316 to the
CA 02255092 1998-11-30
24
power-on position rotates the return post 348 into a
position where it is engaged by one of the power
disengaging surfaces 346. Engagement of the return post
348 by one of the power disengaging surfaces 346 returns
the switch body 316 and rotatable switch plate 304 to the
power-off position as the first belt terminator 300 is
withdrawn from the first belt terminator receptor 302.
To lockably engage the first belt terminator 300 in
the first belt terminator receptor 302, a first
terminator latch 350 is provided which is configured to
slidably engage the first belt terminator 300 and
lockably engage a first terminator latch groove 352. The
first terminator latch 350 is mounted on a leaf spring
354 to allow the first terminator latch 350 to
resiliently slide over the surface of the first belt
terminator 300 and lockably engage the first terminator
latch groove 352.
To disengage the first terminator latch 350, a
disengaging column 356 is provided which may be raised by
a column cam surface 358 shown in Figure 5 on the first
terminator release tab 310 as the first terminator
release tab 310 is pivoted away from the bottom surface
306 of the case 308. The disengaging column 356 engages
the leaf spring 354 and raises it as the disengaging
column 356 is raised, thus lifting the first terminator
latch 350 from the first terminator latch groove 352.
Figure 7 is a partially exploded isometric view
showing another embodiment of a first belt terminator 360
and an associated first terminator receptor 362, which
function similarly to the embodiment shown in Figures 4-
6, but which employ different structure to lockably
engage the first belt terminator 360 in the first
terminator receptor 362.
The first belt terminator 360 and the first
CA 02255092 1998-11-30
terminator receptor 362 again serve to cooperatively
activate a power switch 364, which has a power switch
body 366 which is rotatably mounted with respect to a
case 368. Again, the power switch body 366 has an
5 advancing post 370 and a return post 372 which, when
engaged by probes 374 on the first belt terminator 360,
rotate the power switch body 366 to move the power switch
364 between its power-on and power-off positions.
10 The probes 374 of the first belt terminator 360 each
have a probe catch surface 376 thereon. The probes 374
are preferably configured such that the probe catch
surfaces 376 also serves as power disengaging surfaces,
which are discussed in detail above.
In this embodiment, a spring-loaded latch assembly
378 is provided in the first terminator receptor 362 to
lockably engage the first belt terminator 360. The latch
assembly 378 is biassed upwards by a latch spring 380
residing in a latch spring casing 382 which resiliently
and rotatably engages the power switch body 366. The
latch assembly 378 has a pair of locking catches 384
(only one of which is shown) which are engaged by the
probes 374 when the first belt terminator 360 is placed
into the first terminator receptor 362. The latch spring
380 biasses the locking catches 384 into a raised
position where they engage the probe catch surfaces 376
of the probes 374.
To depress the latch assembly 378 to remove the
first belt terminator 360 from the first terminator
receptor 362, a first terminator tab 386 is pivotably
mounted to the power switch body 366. The first
terminator tab 386 has a tab lifting end 388 which, when
raised by the user, pivots a tab depressor cam surface
390 downwards. The tab depressor cam surface 390
forcibly engages the latch spring casing 382 to move the
latch assembly 378 against the bias of the latch spring
CA 02255092 1998-11-30
26
380 to a lowered position where the probes 374 may be
withdrawn past the locking catches 384.
This embodiment also preferably employs a spring-
s loaded flap 392 which is pivotably mounted to the case
368. The spring-loaded flap 392 is biassed to cover the
first terminator receptor 362 when the first belt
terminator 360 is removed therefrom, and thus serves to
prevent snow and debris from entering the first
terminator receptor 362
Figure 8 is a rudimentary embodiment of a second
belt terminator 400 and a second belt terminator receptor
402 which form an assembly serving to attach a belt 404
to a case 406 which houses a transmitter, a receiver and
an antenna (not shown). This assembly also controls
whether the transmitter is activated or the receiver is
activated. In this embodiment, the second belt
terminator receptor 402 is positioned at a second harness
support end region 408 of the case 406 and is attached to
a bottom surface 410 of the case 406.
The second belt terminator 400 interacts with the
second belt terminator receptor 402 and a mode switch 412
which resides in the second belt terminator receptor 402.
The mode switch 412 controls whether the rescue device is
in the transmit mode or the receive mode by closing
either a pair of receiver contacts 413a or a pair of
transmitter contacts 413b. The mode switch 412 is
biassed by a spring 414 such that the device is in the
receive mode when the second belt terminator 400 is not
engaged with the second belt terminator receptor 402.
The second belt terminator 400 has a terminator base
416, to which the belt 404 attaches, and a terminator arm
418, which is designed to be inserted into the second
belt terminator receptor 402. The terminator arm 418 is
provided with a second terminator latch 420 for lockably
CA 02255092 1998-11-30
27
engaging the second belt terminator 400 with the second
belt terminator receptor 402 when it is fully inserted
therein. A latch release button 422 is provided to
disengage the second terminator latch 420. Guide
surfaces 424 are provided internal to the second belt
terminator receptor 402 and serve to direct the
terminator arm 418 toward the mode switch 412. As the
terminator arm 418 is advanced, it engages and moves the
mode switch 412, compressing the spring 414 and toggling
the mode switch 412 to the transmit mode. At this
position, the second terminator latch 420 engages the
second belt terminator receptor 402 to secure the belt
404 to the case 406 and assure that the rescue device
remains in the transmit mode until an affirmative action
is taken to disconnect the belt 404.
While the embodiment of Figure 8 assures that the
device is in the transmit mode when the second belt
terminator 400 is connected to the case 406, which is
typically the situation when a party is likely to be
buried by an avalanche, there is also the possibility
that the searcher could be buried in a secondary
avalanche while searching for a buried party. If this
occurs, the buried searcher may be restricted in motion,
and thus unable to reconnect the second belt terminator
400 with the second belt terminator receptor 402 to
return the rescue device to the transmit mode. Thus, for
increased safety, it is preferred to have a secondary
means for placing the rescue device in the transmit mode.
Figure 9 illustrates an improved rescue device which has
the important feature of a secondary quick-acting
supplemental means for toggling the rescue device to the
transmit mode. This embodiment thus provides a dual-
action mode toggle system which has utility independent
of its use in the rescue device of the present invention.
Figure 9 is a partially exploded isometric view of a
second belt terminator 500 which is designed to be used
CA 02255092 1998-11-30
28
in combination with a second belt terminator receptor 502
which allows the rescue device to be placed in the
transmit mode either by inserting the second belt
terminator 500 into the second belt terminator receptor
502 or, alternatively, by depressing a mode switch 504
which extends beyond a case 506 which encloses a
transmitter, a receiver, and an antenna of a rescue
device. In this embodiment, the second belt terminator
receptor 502 is an integral part of the case 506. The
second belt terminator 500 has a pair of terminator arms
508 which extend from a terminator base 510.
The mode switch 504 has a mode switch body 512 and
terminates in a switch head 514 and a switch shank 516.
The mode switch body 512 is translatably mounted in the
second belt terminator receptor 502 such that the switch
head 514 is exposed extending beyond the case 506 when
the mode switch 504 is in a receive mode position. In
the receive mode position, the mode switch 504 places a
contact surface 518 on the mode switch body 512 in
position to close receiver contacts 520. The switch
shank 516 is slidably mounted in a shank bracket 522,
which in turn is secured with respect to the case 506 to
assure that the translational motion of the mode switch
body 512 is substantially normal to a second case end
section 524. The mode switch body 512 is biassed to the
receive mode position by a shank spring 526 which
compressively engages the shank bracket 522 and a spring
rest 528 on the mode switch body 512.
The mode switch body 512 is provided with at least
one switch body catch 530, and more preferably a pair of
switch body catches 530 are provided. In the embodiment
illustrated in Figure 9, a pair of switch body catches
530 are employed which are symmetrically disposed on the
mode switch body 512. Each of the switch body catches
530 engages a catch retainer 532 which is slidably
mounted to the case 506 and is biassed toward the mode
CA 02255092 1998-11-30
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switch body 512 by a catch retainer spring 534. Each
catch retainer 532 has a catch engaging surface 536,
which in turn contains a catch receptor 538 therein.
When a searcher is using the rescue device in the
receiver mode to conduct a search, the second belt
terminator 500 is typically disengaged from the search
device. If the searcher is buried by a secondary
avalanche while searching, then the searcher can, with
minimum motion, depress the switch head 514 until it is
substantially flush with the case 506, as shown in
phantom, which causes the pair of catches 530 to slide
along the catch engaging surfaces 536 of the
corresponding catch retainer 532. This motion also moves
the contact surface 518 away from the receiver contacts
520, disabling the receiver, and advancing the contact
surface 518 so as to engage transmitter contacts 540 to
place the rescue device in the transmit mode.
When the mode switch body 512 is so depressed, each
of the pair of switch body catches 530 engages the
corresponding catch receptor 538, which maintains the
mode switch body 512 in the receiver mode until an
affirmative action is taken by the searcher to restore
the rescue device to a transmit mode. This affirmative
action can be the reinsertion and subsequent removal of
the second belt terminator 500, which results in the mode
switch body 512 returning to the transmit mode. However,
the embodiment of Figure 9 provides an alternative
mechanism to return the rescue device to the receive mode
which is not dependent on the availability of the harness
assembly which contains the second belt terminator 500.
In this case, returning to the receive mode can be
accomplished by pushing spreading tabs 542 provided on
the catch retainers 532, thus moving the catch receptors
538 away from engagement with their respective switch
body catches 530.
CA 02255092 1998-11-30
In this embodiment, the contact surface 518 is so
positioned as to assure engagement with the transmitter
contacts 540 before such time as the paired switch body
catches 530 lockably engage the catch receptors 538. The
5 transmit mode of operation may be activated by the second
belt terminator 500, which has a switch head engaging
surface 544, when the switch head engaging surface 544
depresses the switch head 514 as the terminator arms 508
are advanced along guide surfaces 546. The terminator
10 arms 508 have catch retaining spreader surfaces 548 which
slidably engage mating catch retainer spreading surfaces
550 to assure that the paired switch body catches 530 are
not lockably engaged by the catch receptors 538. This
assures that the mode switch body 512 will return to the
15 receive mode when the second belt terminator 500 is
removed from the second belt terminator receptor 502.
Figures 10 and 11 illustrate an alternative second
belt terminator 600 and an associated second belt
20 terminator receptor 602 which function similarly to the
second belt terminator 500 and second belt terminator
receptor 502 discussed above. In this embodiment,
spring-loaded flaps 604 are employed to cover the second
belt terminator receptor 602 when the second belt
25 terminator 600 is removed therefrom, as is shown in
Figure 10.
The second belt terminator 600 and the second belt
terminator receptor 602 are again interactive with a mode
30 switch 606 having a mode switch body 608. The mode
switch body 608 is again provided with switch body
catches 610, and catch retainers 612 are slidably mounted
to a case 614.
In this embodiment, the second belt terminator 600
has two terminator arms 616 which forcibly engage the
spring-loaded flaps 604 as the second belt terminator 600
is inserted into the second belt terminator receptor 602.
CA 02255092 1998-11-30
31
This engagement forces the spring loaded flaps 604 to
engage catch retainer spreading surfaces 618 on each of
the catch retainers 612, moving the catch retainers 612
away from engagement with the switch body catches 610, as
shown in Figure 11.
This embodiment also differs in the type of switch
contact arrangement used to toggle the mode of operation.
In this embodiment, a roller switch 620 is employed. As
a shank 622 is advanced by the mode switch body 608, the
roller switch 620 is contacted by the shank 622 which, as
it advances, changes the switch 620 from closing a first
set of contacts 624 to closing a second set of contacts
626.
Figures 12 and 13 illustrate an improved rescue
device 700 which is similar to the rescue device 100
shown in Figure 1, and which employs a preferred harness
arrangement for attaching a case 702 to a user 704 (shown
in phantom). The case 702 is attached via a first belt
terminator 706 and a second belt terminator 708. As
discussed above, attachment of the first belt terminator
706 to the case 702 controls the power to the device 700,
while attachment of the second belt terminator 708 to the
case 702 toggles the device 700 between a transmit mode
and a receive mode. The device 700 has both a waist belt
710 and a shoulder belt 712. The waist belt 710 is
connected to both the first belt terminator 706 and the
second belt terminator 708, and passes around the waist
of the user 704 to maintain the case 702 in close
proximity to the user 704, as shown in Figure 12. The
shoulder belt 712 is connected to the waist belt 710 by a
harness connector 714 which slidably engages the waist
belt 710. The shoulder belt 712 passes over the shoulder
of the user 704.
As discussed above, when the first belt terminator
706 and the second belt terminator 708 are both attached
CA 02255092 1998-11-30
32
to the case 702, the device 700 is powered in the
transmit mode. When the user 704 desires to conduct a
search, the second belt terminator 708 is detached from
the case 702 as shown in Figure 13, which places the
device 700 in the receive mode. The first belt
terminator 706 remains attached to the case 702, assuring
that the power to the device 700 is on. The first belt
terminator 706 also maintains the case 702 connected to
the user by the waist strap 710 and the shoulder strap
712, preventing accidental loss of the device 700. The
shoulder strap 712 is connected to the waist belt 710 via
the harness connector 714 so as to provide a sufficient
length of the waist belt 710 to allow the user 704 to
hold the case 702 in a position where a dial 716 can be
readily manipulated and a display 718 can be readily
seen. Such a position facilitates the user 704 operating
the device 700 to conduct a search.
The device 700 is particularly useful in situations
where multiple searchers are present. All searchers must
have their rescue devices switched to the receive mode to
begin searching, to prevent stray transmissions from
interfering with the signal transmitted by the buried
party. Since the device 700 is detached from engagement
around the waist of the user 704 when switched to the
receive mode, searchers can readily visually determine
whether the device 700 has been so switched. This
feature allows easier coordination between multiple
searchers, allowing the search to be conducted with
decreased delay.
Figure 14 illustrates an on-board rescue analysis
system 800 of the present invention. The rescue analysis
system 800 has a signal pre-processor 802 which receives
an antenna signal 804. The antenna signal 804 is
generated by the transmitter of the buried party and.is a
457 kHz modulated signal. The signal pre-processor 802
converts the antenna signal 804 to a pre-processed signal
CA 02255092 1998-11-30
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806 which is preferably a demodulated 2 kHz signal. The
signal pre-processor 802 may amplify the antenna signal
804 in addition to demodulating it.
The pre-processed signal 806 is fed to a manually
operated multistage amplifier 808, having N stages, which
generates a working signal 810. The working signal 810
is fed to a speaker 812 and to a signal processing system
814. Means for sensing the stage at which the multistage
amplifier 808 is operating 816 are also provided, which
report the stage of the multistage amplifier 808 to the
signal processing system 814.
The signal processing system 814 employs the working
signal 810 in combination with the information on the
stage of the multistage amplifier 808 to provide prompts
for the rescuing party as to how to proceed with the
search. The signal processing system 814 may first
condition the working signal 810 using components such as
a rectifier, A-D converter, etc., to convert the working
signal 810 to a format compatible with the signal
processing system 814. Preferably, a LCD screen is
employed to display the prompts. These prompts are
prefereably icons that are designed to be suggestive to
the searching party as to what action should be taken.
The signal processing system 814 is provided with a
means for determining whether a coarse search or a pin-
point search should be conducted 840. This means uses
either the working signal 810 and an index for the stage
at which the amplifier 808 is operating, or uses the pre-
processed signal 806 in combination with means for
establishing whether the pre-processed signal 806
corresponds to a signal from a transmitter located at
more than about 80 m or less than about 1 m. If the
level of the signal (810 or 806) is such as to indicate
that the transmitter is located more than about 80 m
away, a coarse search icon is displayed, while if the
CA 02255092 1998-11-30
34
transmitter is located less than about 1 m away, a pin-
point search icon is displayed. Figures 15 and 16
respectively illustrate preferred graphic symbols for a
coarse search icon 842 and a pin-point search icon 844.
The signal processing system 814 also has a means
for determining whether there is a need to change the
stage of the amplifier and provide notice of such 846.
This means most conveniently uses the working signal 810
and provides a scale up icon 848 (see Figure 17) or a
scale down icon 850 (see Figure 18) as the limits of the
current stage of the multistage amplifier are reached.
The scale up icon 848 is displayed when the lower limit
of the stage is reached, prompting the searcher to switch
to a stage having greater amplification, while the scale
down icon 850 is displayed when the upper limit of the
stage is reached. The icons (848 and 850) respectively
illustrated in Figures 17 and 18 are preferred icons
which are felt to suggest the action to be taken by the
searcher.
Since it is important for the search to advance in a
systematic manner, the searcher should proceed along a
field line. In order to assist in maintaining the search
on a field line, the signal processing system 814 is
provided with means to provide notice when the rescue
device should be reoriented with respect to the field
line 852 and provides a reorient icon 854 as illustrated
in Figure 19.
The signal processing system 814 also preferably has
means for graphically displaying the working signal's
relative strength 856. This means preferably generates a
bar graph 858, which is more preferably framed by an
arrow icon 860 as shown in Figures 16, 18, and 19.
It is further preferred that means for analyzing one
of the signals generated by the receiver and converting
CA 02255092 1998-11-30
the strength of the signal to an estimated distance along
a field line to the buried transmitter 862 be provided.
This means generates a digital distance indication 864
such as is illustrated in Figures 16 and 18.
5
Preferably, means are provided for temporarily
displaying all of the icons (842, 844, 848, 850, 854,
858, 860, and 864) when power is initially provided to
the rescue analysis system 800, to provide notice to the
10 user that all icons are functioning properly.
Preferably, a battery level chwecking means is
provided, with an associated battery strength indicator
to indicate to the user the remaining battery life. This
15 means is activated when the device is first placed in the
transmit mode so that the user will be placed on notice
as to the battery condition before being placed in a
situation where the user must rely on the performance of
the device.
All of the above described means can be implemented
in either circuitry or with a microprocessor. An example
of a microprocessor-based signal processing system
follows .
Figure 20 illustrates an on-board rescue analysis
system 900 of the present invention. The rescue analysis
system 900 has a signal pre-processor 902 which receives
an antenna signal 904. The antenna signal 904 is
generated by the transmitter of the buried party.
Currently, the antenna signal 904 is a 457 kHz modulated
signal. The signal pre-processor 902 converts the
antenna signal 904 to a pre-processed signal 906 which is
a demodulated 2 kHz signal.
The pre-processed signal 906 is fed to a manually
operated multistage amplifier 908, having N stages, which
generates an amplified working signal 910. The working
CA 02255092 1998-11-30
36
signal 910 is fed to a speaker 912.
The working signal 910 is also fed to a signal
conditioner 914. The signal conditioner 914 in turn
generates a microprocessor input signal 916. An
amplifier level sensor 918 monitors the stage in which
the multistage amplifier 908 is operating and provides a
machine-readable stage level signal 920 which indicates
the level of the stage at which the multistage amplifier
908 is operating.
A microprocessor 922, in combination with
instruction sets 924, operates on the microprocessor
input signals 916 and the stage level signal 920 to
provide microprocessor output 926, which contains
processed data for subsequent display as well as routing
instructions to direct such to the appropriate display.
In all cases, display signals 928 from the microprocessor
output 926 are directed to a display driver 930 which
drives a display 932. Preferably, the microprocessor 922
also directs the microprocessor output 926 to display
lights 934.
Figure 21 illustrates the on-board rescue analysis
system 900 housed in a case 936 which also houses an
antenna, a transmitter, and a receiver in a manner
similar to the case 102 shown in Figure 1. The display
932 is preferably a liquid crystal display and is mounted
in a top surface 938 of the case 936. Any display lights
934 are also mounted in the front face 938, and it is
preferred for the front face 938 to be employed to mount
the speaker 912 and a dial 940 for manually operating the
multistage amplifier 908.
Figure 22 illustrates a flow diagram illustrating
one example of how the various instruction sets 924 are
sequentially implemented. The instruction sets 924
include a scale routine 942, a pin-point search routine
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944, a coarse search routine 946, a field line alignment
routine 948, a reorient routine 950, a change stored
value routine 952, and a bar graph generator routine 954.
The microprocessor input signal 916 is operated on
by the scale routine 942. The scale routine 942 contains
an instruction set that directs the microprocessor 922 to
compare the microprocessor input signal 916 with a scale
range SR. The scale range SR is the range between a
scale maximum value, which is the saturation level for
the speaker 912, and a scale minimum value, which is the
minimum level which produces an audible sound from the
speaker 912.
If the microprocessor input signal 916 is greater
than M% of the scale range SR, then control of the
microprocessor 922 is passed to the pin-point search
routine 944. The pin-point search routine 944 reads the
value of the stage level signal 920 and, if the stage
level signal 920 is equal to N, indicating that the
shortest range (least sensitive) stage is selected, the
pin-point search routine 944 directs the display driver
930 to generate a pin-point search icon and send the pin-
point search icon to the display 932. If the value of
the stage level signal 920 is less than N, then the pin-
point search routine 944 directs the display driver 930
to generate a change scale icon (preferably change scale
down icon) and send it to the display 932.
If the microprocessor input signal 916 is less than
L% of the scale range SR, then the control of the
microprocessor 922 is passed to the coarse search routine
946. The coarse search routine 946 reads the value of
the stage level signal 920 and, if the stage level signal
920 is 1, indicating that the longest range (most
sensitive) stage is selected, the coarse search routine
946 directs the display driver 930 to generate a coarse
search icon and send the coarse search icon to the
CA 02255092 1998-11-30
38
display 932. If the value of the stage level signal 920
is greater than 1, then the coarse search routine 946
directs the display driver 930 to generate a change scale
icon (preferably change scale up icon) and send it to the
display 932.
If neither of the above conditions are met, then the
microprocessor input signal 916 is passed to the field
line alignment routine 948. The field line alignment
routine 948 stores a stored value S, which is initially
selected as an initial value of the microprocessor input
signal 916. This stored value S is maintained for a
fixed period of time at, after which it may be replaced
by the current value of the microprocessor input signal
916 as discussed below. The field alignment routine 848
compares the microprocessor input signal 916 against the
stored value S. If the current value is less than S by
X%, then control is passed to the reorient routine 950
which directs the display driver 930 to generate a
reorient icon and send it to the display 932. In
addition to display of the reorient icon, or as an
alternative thereto, the reorient routine 950 may direct
the display driver 930 to cease display of any other
icons when the current value of the microprocessor input
signal 916 is less than S by X%.
If the microprocessor input signal 916 is greater
than S, then the control is transferred to the change
stored value routine 952, which replaces S with the
current value of the microprocessor input signal 916, and
the microprocessor input signal 916 is sent to a bar
graph generator routine 954 which directs the display
driver 930 to generate a bar graph and send it to the
display 932.
In the event that the signal control is not
transferred as discussed above, then the microprocessor
input signal 916 is sent to the bar graph generator
CA 02255092 1998-11-30
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routine 954 which directs the display driver 930 to
generate a bar graph and send it to the display 932.
In all cases where the display driver 930 is
directed to generate an icon for display, if a
corresponding display light 934 is provided, the
appropriate routine also causes such display light 934 to
be activated. As an example of how such may be achieved,
Figure 22 shows a display light 934' which is controlled
by the reorient routine 950. The display light 934' is
energized via a relay 956 which is normally open. When
the current value of the microprocessor input signal 916
is less thanes by X %, the reorient routine 950 directs a
relay driver 958 to close the relay 956 to energize the
display light 934'.
While the novel features of the present invention
have been described in terms of particular embodiments
and preferred applications, it should be appreciated by
one skilled in the art that substitution of materials and
modification of details obviously can be made without
departing from the spirit of the invention.
