Device with water-activated, automatic disconnect

A technique for managing an attachment between first and second portions of a device. The technique includes a retaining component having a first state in which the retaining component maintains the attachment between the first and second portions by virtue of a rigid characteristic and a second state in which the retaining component loses the rigid characteristic and no longer maintains the attachment. The retaining component transitions from the first state to the second state upon exposure to liquid water.

BACKGROUND

Hurricanes in the United States cause billions of dollars in damages annually with an average death rate of nearly 20 persons per year. Accurate measurements in and around hurricanes are critical for predicting hurricane intensity, and thus the severity of risks posed to human life and property. Current approaches to measuring hurricane-related factors employ buoys, sondes, and dropsondes. Buoys are floating devices that make measurements near the surface of a body of water and store collected data, which may be retrieved directly by visiting the buoys or by receiving the data over a wireless link. Sondes are devices that operate within a body of water and collect data as they descend. Relevant data may include conductivity, temperature, and depth, for example. Dropsondes are sondes adapted for deployment from an aircraft. A dropsonde can measure atmospheric conditions while falling through the air. After splashdown, a dropsonde can measure water conditions as it sinks through the water. Sondes and dropsondes may log their data while operating under water and transmit the logged data upon resurfacing. Some sondes and dropsondes may perform “profiling,” i.e., controllably rising and sinking to various depths and measuring water columns at different locations.

Dropsondes typically deploy parachutes that enable them to fall through the air at controlled speeds and typically jettison their parachutes upon splashdown. For example, a dropsonde may include a sensor that detects sudden deceleration or contact with water and an actuator that detaches the parachute upon such detection.

SUMMARY

Unfortunately, prior disconnect mechanisms for dropsondes and other devices can be expensive and complex. Actuators consume power and valuable space; they also increase weight. Further, the types of devices described above typically operate in wet, saline environments, which can pose short-circuit risks to electronically controlled actuators.

In contrast with prior approaches, an improved technique for managing an attachment between first and second portions of a device includes a retaining component having a first state in which the retaining component maintains the attachment by virtue of a rigid characteristic and a second state in which the retaining component loses the rigid characteristic and no longer maintains the attachment. The retaining component transitions from the first state to the second state upon exposure to liquid water. Advantageously, the improved technique requires no power, sensor, or control circuitry and operates reliably in salt-water environments.

Certain embodiments are directed to an apparatus. The apparatus includes a first portion, a second portion, and a retaining component. The retaining component has a first state and a second state. In the first state, the retaining component is configured to have a rigid characteristic and to hold the first portion to the second portion. In the second state upon exposure to liquid water, the retaining component is configured to lose its rigid characteristic and to free the first portion from the second portion.

Other embodiments are directed to a method of managing an attachment between a first portion and a second portion of a device. The method includes providing a retaining component having a first state and a second state, the retaining component configured in the first state to have a rigid characteristic and to hold the first portion to the second portion, the retaining component configured in the second state to lose its rigid characteristic upon exposure to liquid water. With the retaining component in the first state, the method further includes the device becoming at least partially submerged in water. The method further includes the device allowing water to pass to the retaining component, the retaining component thereupon transitioning from the first state to the second state and freeing the first portion from the second portion.

The foregoing summary is presented for illustrative purposes to assist the reader in readily grasping example features presented herein; however, this summary is not intended to set forth required elements or to limit embodiments hereof in any way. One should appreciate that the above-described features can be combined in any manner that makes technological sense, and that all such combinations are intended to be disclosed herein, regardless of whether such combinations are identified explicitly or not.

DETAILED DESCRIPTION

Embodiments of the disclosed technique will now be described. One should appreciate that such embodiments are provided by way of example to illustrate certain features and principles but are not intended to be limiting.

A technique for managing an attachment between first and second portions of a device includes a retaining component having a first state in which the retaining component maintains the attachment by virtue of a rigid characteristic of the retaining component and a second state in which the retaining component loses the rigid characteristic and no longer maintains the attachment. The retaining component transitions from the first state to the second state upon exposure to liquid water.

FIG. 1shows an example device102with which embodiments of the improved technique can be practiced. Here, multiple modules106are arranged end-to-end along an axis104of the device102. The depicted modules106include a nose module110, a variable buoyancy module120, an electronics module130, a communications module140, and a parachute module150. Other embodiments may include a greater or fewer number of modules106, and such modules may be of different types and/or capabilities from those shown. The depicted example is merely illustrative.

FIG. 2shows the device102in additional detail. Here, nose module110is seen to include environmental sensors, such as a CTD (conductivity, temperature, and depth) sensor112, and ballast (e.g., weights)114. The ballast114assists in keeping the nose module110pointing down and the device102vertical when the device102is submerged in water. Nose module110has a convex outer surface116, which may be hemispherically shaped, for example, to enable the device102to descend smoothly under water. In some examples, nose module110has a concave inner surface118adapted for receiving a convex outer surface126of variable buoyancy module120.

Variable buoyancy module120is configured to vary its own buoyancy, and hence the buoyancy of the overall device102, in response to electronic control. To this end, variable buoyancy module120enables the device102to controllably rise and fall within a water column.

Electronics module130is connected to the variable buoyancy module120and includes, for example, a power source such as a battery132and an electronics assembly134. As shown, the electronics assembly134is electrically connected to the CTD sensor112(and any other environmental sensors in the nose module110), e.g., via a cable that passes through the variable buoyancy module120. In some examples, the electronics assembly134includes a microcontroller, microprocessor, or the like, as well as associated memory. It may further include an IMU (inertial measurement unit) and electronics for supporting GPS, SATCOM, and/or RF communications, such as interfaces to antennas provided in the communications module140. In some examples, the power source may be provided in some other module, such as in the variable buoyancy module120or in a separate module (e.g., a battery module).

In the example shown, communications module140includes a satellite communications (SATCOM) antenna142and a GPS (Global Positioning System) antenna144, which may be electrically connected to the circuit assembly134via cables160. In some examples, one or more RF (Radio Frequency) antennas may be provided, to support RF communication. Communications module140may preferably have a convex outer surface146, e.g., for facilitating upward movement of the device102through water. The convex outer surface146is preferably made of a non-conductive material, such as poly-vinyl chloride (PVC), to allow electromagnetic signals to readily pass therethrough. The convex outer surface146is adapted to mate with a partially-concave inner surface156in the parachute module. In some examples, the communications module140may include an extendible mast (FIG. 8B) with antennas disposed at a remote end and/or along a length thereof. The extendable mast may serve to raise antennas away from the water surface to improve signal strength.

Parachute module150preferably has a detachable connection to communications module140. As will be described more fully below, a fastener210in the communications module140attaches to the parachute module150and abuts a retaining component220that holds the parachute module150in place. Spring154applies a biasing outward force. The retaining component220is configured to soften or dissolve upon contact with liquid water, allowing the spring154to pull the fastener210through the retaining component220and out of the communications module140, and thus to separate the parachute module150from the communications module140.

FIG. 3shows an example deployment of a device102for making measurements in an aqueous environment. As shown, an airplane or other aircraft310drops or otherwise ejects a device102, which begins falling through the air. Parachute152opens, and device102begins a slowed descent, falling nose-first, i.e., with nose module110pointing down. Depending on application, the device102may monitor environmental factors of the air, such as temperature, pressure, humidity, particulate matter, and so forth, as it descends to through the atmosphere. Device102may also monitor its own location and altitude, e.g., using GPS. The device102may log the results and/or transmit the results, e.g., via SATCOM, to a remote receiver (not shown).

The device102eventually splashes down, striking the surface320of a body of water. In some examples, the device102collects surface data at this time. After exposure to liquid water, the parachute module150automatically detaches from the device102. The device102then begins to descend toward the floor330of the body of water, leaving the parachute module150behind. The device102continues to log data as it goes. For example, device102may repeatedly measure conductivity, temperature, and depth. Depending on the mission, the device102may perform profiling, e.g., by action of the variable buoyancy module120, alternately ascending and descending and making measurements of different water columns. Once measurements have been made, the device102ascends to the surface320, whereupon the device102transmits the contents of its data log wirelessly to a receiver. Alternatively, personnel may retrieve the device102and read its data directly.

FIG. 4shows an example attachment between the communications module140and the parachute module150in greater detail. The additional modules106ofFIG. 1are omitted from the figure for simplicity. In the example shown, the parachute152has deployed from the parachute module150and the device102has landed in water. The parachute152remains anchored to the parachute module150via a parachute anchor410.

As shown in the main figure and in the magnified partial view to the right, the fastener210includes a tapered head210h, a shaft210sthat extends from the head210h, and threads210tformed at a distal end of the shaft210s. The threads210tengage with a threaded hole150hformed within an internal wall150aof the parachute module150.

In the example shown, the retaining component220has an annular shape and a central hole through which the fastener210extends. A shown to the right of the figure, the retaining structure220includes a frame having an outer wall220a, internal fingers220b, and spokes220c. Contained within the frame is a bobbin pill220d. The bobbin pill220dis composed of a material that is initially rigid and has high compressive strength, even in humid air, but which softens and/or dissolves when exposed to liquid water. Suitable materials for the bobbin pill220dinclude microcrystalline cellulose. Bobbins of this type are commercially available from numerous sources, including Halkey-Roberts Corporation of St. Petersburg, Fla.

The internal fingers220bof the retaining component have internally-projecting steps220e. In an assembled state, a cone-shaped projection150bfrom the wall150aof the parachute module150extends down and rests on the steps220e. In this condition, the fastener (e.g., a screw or bolt) may be tightened into the threaded hole in the wall150auntil the head210hof the fastener abuts the internal fingers220bof the retaining structure220. In this condition, the spring154is compressed between a top140aof the communications module140and the internal wall150aof the parachute module150. The spring154in this example is a conical spring, but other forms of springs may be used. In addition, one should appreciate that the spring154may be optional in some embodiments, as mild agitation by waves, wind, and/or currents may be sufficient to separate the two modules without requiring a spring. Also, the spring154may be implemented as a magnetic, hydraulic, or pneumatic spring, rather than as a mechanical spring as shown.

In the illustrated arrangement, it is only the retaining structure220that prevents the modules140and150from separating. For example, if the retaining structure220were absent, the head of the fastener210would pull out of the communications module140and the parachute module150would float away.

Effectively this action takes place when the device102lands in water. Passageways420and422allow liquid water to enter the top of the communications module140and reach the retaining component220, bathing the bobbin pill220din water and causing it to lose its initial rigidity, e.g., by dissolving. When the bobbin pill220dsoftens, the internal fingers220bsplay open, e.g., due to the force of the spring154driving the tapered head210hof the fastener210through the opening at the top of the module140. As the retaining component220can no longer prevent the modules140and150from separating, the repulsive force of the spring154pushes up on the parachute module150, pulling the head210hof the fastener210completely out of the communications module140and freeing the parachute module150from the communications module140.

One should appreciate that the passageways420and422normally prevent water from entering the module140unless the device102is at least partially submerged in water. For example, with the device102oriented vertically, as is the case when the device102is carried by the parachute152, the passageways422are angled down so as to prevent raindrops or runoff from rain from entering the module140. Rather, it is only when the device102is submerged above the level of the passageways422that water may enter the module140. In some examples, passageways420and422include baffling to further prevent water entry unless the module140is submerged. Such baffling may take the form of partial walls and/or circuitous routes that restrict sloshing and ensure that the retaining structure220is exposed to liquid water only in the event of at least partial submergence. Some examples do not require such baffling, however.

FIGS. 5A and 5Bshow various levels of separation. InFIG. 5A, the head210hof the fastener210has partially pulled through the retaining component220, with the internal fingers220bsplaying open. Spokes220care easily compressed or pushed aside. As shown inFIG. 5B, the two modules140and150have completely separated. Spring154is fully extended.

FIGS. 6A and 6Bshow example features of the retaining structure220in additional detail.FIG. 6Ais a bottom view and shows the outer wall220a, which extends completely around and contains the bobbin pill220d, and internal fingers220b(8fingers shown in the figure), which support the bobbin pill220dinternally. The internal fingers220balso provide an abutment for the head of fastener210. Each finger220bhas a respective step220e. The retaining structure220is seen to have an annular shape and a central hole610through which the fastener210may pass.

FIG. 6Ais a top view of the retaining structure220and further shows spokes220c, e.g., one spoke220cfor each finger220b. The spokes220care flexible and easily deformed.

FIG. 7is a perspective sectional view of an example device102, showing an example communications module140, parachute module150, and attachment therebetween. In this example, the communications module140includes an antenna assembly710, which includes a substrate720(e.g., a circuit board or other carrier), a satellite communications antenna730and a GPS (Global Positioning Service) antenna740). As shown by non-limiting example, the substrate720of the antenna assembly710may be disk-shaped and may include a central hole722. Certain details of the modules140and150may differ slightly from those shown in previous figures, underscoring the diversity of embodiments that are contemplated.

FIGS. 8A and 8Bshow yet another embodiment, which may provide for improved signal communications via the antenna assembly710. As shown inFIG. 8A, the antenna assembly710is positioned outside the communications module140, sandwiched between the two modules140and150. Cabling810(i.e., one or more cables) convey signals from antenna assembly710into the communications module140, e.g., via a waterproof penetrator820, such as a potted bore or a submersible connector. The cabling810may further extend into the electronics module130, e.g., via a tube830. In an example, the cabling810is packed inside the spring154. For example, the spring154has a central region154athat can accommodate cabling810. The cabling810is long enough to reach the parachute module150when the spring154is fully extended. A somewhat longer version of spring154may be provided for this embodiment as compared with the embodiments described above, to support longer extension and to enable the spring154to server as a mast850. Also, the spring154in this example may have a fixed attachment both to the top of the parachute module150and to the antenna assembly710.

Optionally, a second spring854, such as another conical spring, may be placed between the antenna assembly710and the parachute assembly150, to ensure complete separation of the parachute module150from the electronics assembly710when the parachute module150disconnects. The second spring854may not be required in certain embodiments, however.

Disconnection of the parachute module150proceeds much as described above. For example, the device102lands in water. Water enters the communications module140and reaches the retaining component220. The retaining component220transitions upon exposure to liquid water from a first state in which the retaining component220is rigid to a second state in which the retaining component loses its rigidity and becomes compliant. Once the retaining component220transitions from the first state to the second state, the retaining component220can no longer hold back the head of fastener210. Under the influence of spring154, the head of the fastener pulls through the retaining component220and out the top of the communications module140.

FIG. 8Bshows an example result of separation. After pulling through the top of the communications module140, the fastener210pulls through the antenna assembly710(FIG. 7) and is carried away with the parachute module150, which fully disconnects from the device102. The spring154has fully released and forms a mast850that extends from the communications module140to the antenna assembly710. The mast850has sufficient length so that it extends above the surface320of the water, thus facilitating wireless communications. In some examples, tendons830may be provided to reduce lateral flexing of the mast850. For example, multiple tendons830are disposed within the spring154and are arranged to cross. Each of the tendons830attaches to the communications module140at one end and to the antenna assembly710at the other end. The tendons830may be composed of an easily-compactable material that resists stretching, such as fabric or string.

FIGS. 9A-9Cshow a variant of the embodiment ofFIGS. 8A and 8B.FIG. 9Ashows the device102prior to separation of module150from module140, with the antenna assembly710placed between the two modules.FIG. 9Bshows the device102with the parachute module hidden but not separated, revealing more fully the antenna assembly710.FIG. 9Cshows the device102after the spring154has extended to form mast850and the parachute module150has been jettisoned.

FIG. 10shows an example method1000of managing an attachment between different portions of a device102and provides a summary of certain features described above. At1010, the device102becomes at least partially submerged in water, as shown inFIG. 3. For example, the device102may be a dropsonde deployed from an aircraft. At1020, the device102allows water to enter the module140, e.g., via passageways420and422, and to pass to the retaining component220. Upon exposure to liquid water, the retaining component220transitions from the first state, in which the retaining component has a rigid characteristic, to the second state, in which the retaining component loses its rigid characteristic and becomes compliant, e.g., by virtue of the bobbin pill220dbecoming wet and softening or dissolving. At1030, upon the transition from the first state to the second state, the parachute module150separates from the communications module140, e.g., as a result of the fastener210pulling through the retaining component220under an imposed force from the spring154. The device102is then free from the parachute module150and is able to descend within the water and to make measurements.

An improved technique has been described for managing an attachment between first and second portions of a device102. The technique includes a retaining component220having a first state in which the retaining component220maintains the attachment by virtue of a rigid characteristic and a second state in which the retaining component220loses the rigid characteristic and no longer maintains the attachment. The retaining component220transitions from the first state to the second state upon exposure to liquid water. Advantageously, the improved technique requires no power, sensor, or control circuitry and operates reliably in salt-water environments.

Having described certain embodiments, numerous alternative embodiments or variations can be made. For example, although embodiments have been described in which the device102is a dropsonde, this is merely an example, as the device102may alternatively be a sonde, a buoy, or any device that may be used in an aqueous environment. Further, the depicted separation of a parachute module150from a communication module140is also merely an example. Thus, separation may be managed between any modules or other portions of the device102. The portions need not qualify as modules, per se, and the device102need not itself be a modular device. For instance, embodiments may involve disconnecting ballast or payload from the device102, or dropping a sensor from a larger module or device.

Although the retaining component220has been shown and described as having an annular shape, it may alternatively have different shapes. Further, it is not required that a fastener pull through the retaining component220. Rather, the retaining component220may be any element having any shape that prevents separation of two portions when dry but allows separation when wet.

Further, although features have been shown and described with reference to particular embodiments hereof, such features may be included and hereby are included in any of the disclosed embodiments and their variants. Thus, it is understood that features disclosed in connection with any embodiment are included in any other embodiment.

As used throughout this document, the words “comprising,” “including,” “containing,” and “having” are intended to set forth certain items, steps, elements, or aspects of something in an open-ended fashion. Also, as used herein and unless a specific statement is made to the contrary, the word “set” means one or more of something. This is the case regardless of whether the phrase “set of” is followed by a singular or plural object and regardless of whether it is conjugated with a singular or plural verb. Also, a “set of” elements can describe fewer than all elements present. Thus, there may be additional elements of the same kind that are not part of the set. Further, ordinal expressions, such as “first,” “second,” “third,” and so on, may be used as adjectives herein for identification purposes. Unless specifically indicated, these ordinal expressions are not intended to imply any ordering or sequence. Thus, for example, a “second” event may take place before or after a “first event,” or even if no first event ever occurs. In addition, an identification herein of a particular element, feature, or act as being a “first” such element, feature, or act should not be construed as requiring that there must also be a “second” or other such element, feature or act. Rather, the “first” item may be the only one. Also, and unless specifically stated to the contrary, “based on” is intended to be nonexclusive. Thus, “based on” should not be interpreted as meaning “based exclusively on” but rather “based at least in part on” unless specifically indicated otherwise. Although certain embodiments are disclosed herein, it is understood that these are provided by way of example only and should not be construed as limiting.