Abstract
An inflatable flotation device having a reaction chamber with reactants that generate gas when mixed, said reactants being separated by a barrier assembly; an activating mechanism adapted to remove or puncture the barrier assembly such that said reactants mix; and an inflatable compartment fluidly connected to the reaction chamber by means of a pressure sensitive passageway, adapted to open only when the pressure of the gas in said reaction chamber exceeds a predetermined threshold. This ensures that most of the reactants are used up to generate gas before the gas enters the inflatable chamber, thus preventing scattering of the reactants. Some implementations have a reaction chamber without a barrier assembly, comprising reactants that generate gas when mixed with water and an activating mechanism adapted to expose the reactants to water. A variety of manual or automatic mechanisms may be employed to activate the reaction and inflate the device.
Claims
1. An inflatable flotation device comprising: a reaction chamber comprising one or more reactants that generate gas when mixed with water; a water inlet valve connecting the reaction chamber to an ambient water environment surrounding the device such that the ambient water surrounding the device fills the reaction chamber when the water inlet valve is open; a sensor indicative of immersion in water for more than a predetermined time, and providing a signal to activate the inflation flotation device; and an inflatable compartment fluidly connected to said reaction chamber by means of at least one pressure sensitive passageway comprising a one-way valve, a semi-permeable membrane or a tail adapted to enable uni-directional gas flow towards the inflatable compartment when the pressure of the gas in the reaction chamber exceeds a predetermined threshold, wherein the predetermined threshold, at which the passageway opens, is that at which the reaction between the reactants and the water is complete, according to a predefined completion criterion, such that the reactants are kept within the reaction chamber until the reaction is complete according to the predefined completion criterion, and wherein the predefined completion criterion at which the reaction between the reactants and the water is considered to be complete is at least one of: (i) 70% of the reaction, (ii) 80% of the reaction, (iii) 90% of the reaction, or (iv) 95% of the reaction.
2. An inflatable flotation device according to claim 1, wherein the at least one pressure sensitive passageway is further adapted to provide substantially preferential passage of the gas rather than the reactants.
3. An inflatable flotation device according to claim 1, wherein the water inlet valve is actuated by a manual actuating mechanism.
4. An inflatable flotation device according to claim 1, wherein the reaction chamber further comprises a water outlet valve, such that the reaction chamber can be emptied after use.
5. An inflatable flotation device according to claim 1, wherein the sensor is adapted to detect any one of vibration, depth, pressure or light.
6. An inflatable flotation device according to claim 1, wherein the reactants are solids.
7. An inflatable flotation device according to claim 1, wherein the at least one pressure sensitive passageway is either a semi-permeable membrane preferentially enabling passage of gases over liquids, or is sufficiently small that it allows substantially preferential passage of the gas rather than the reactants.
8. An inflatable flotation device according to claim 1, wherein at least one reactant is in a non-aqueous state.
9. An inflatable flotation device according to claim 1, wherein the reactants comprise a volume of less than 80 milliliters and generate a sufficient amount of gas for adequate inflation capabilities of the device.
10. An inflatable flotation device comprising: an inflatable compartment; a blister pack assembly within the inflatable compartment, the blister pack assembly comprising a first set of volumes comprising a first reactant and at least a second volume comprising a second reactant, the reactants selected to generate a volume of gas when mixed, and the first set of volumes being separated from the at least second volume by at least one separation layer; wherein, the at least one separation layer is adapted to be removed to enable a reaction to occur between the first and second reactants, such that the gas inflates the inflatable compartment.
11. An inflatable flotation device according to claim 10 further comprising an inner reaction chamber containing the blister pack assembly within the inflatable compartment, such that the reaction chamber is fluidly connected to the inflatable compartment by means of at least one pressure sensitive passageway, adapted to open when the pressure of the gas in the reaction chamber exceeds a predetermined threshold.
12. An inflatable flotation device according to claim 10 further comprising a water inlet valve connecting the inner reaction chamber to an ambient water environment of the device such that the reaction chamber can be filled from the ambient water surrounding the device when the water inlet valve is open.
13. An inflatable flotation device according to claim 10, wherein the separation layer is adapted to be actuated by a manual trigger.
14. An inflatable flotation device according to claim 13, wherein the manual trigger is at least one cord attached to the separation layer.
15. An inflatable flotation device according to claim 10, further comprising a sensor indicative of immersion in water for more than a predetermined time, and providing a signal to activate the inflation device.
16. An inflatable flotation device according to claim 10, wherein the first set of volumes comprises a first plurality of blisters of the blister pack and the at least second volume comprises a second plurality of blisters of the blister pack, such that when the at least one separation layer is removed, the reactants mix.
17. An inflatable flotation device comprising: a reaction chamber comprising reactants that generate gas when mixed, the reactants being separated by a barrier sheet; a pointed element adapted to puncture the barrier sheet such that the reactants mix; and at least one pressure sensitive element adapted to open when the pressure of the gas in the reaction chamber exceeds a predetermined threshold, the pressure sensitive element being disposed between the reaction chamber and a flotation compartment inflatable by the gas.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:
(2) FIGS. 1A and 1B show conceptual cross sections of an exemplary flotation device of the present disclosure, having an inner reaction chamber and outer inflatable compartment, before and after activation respectively;
(3) FIGS. 2A, 2B, and 2C show an isometric view of an exemplary flotation device of the present disclosure before, during, and after inflation respectively;
(4) FIGS. 3A and 3B show an exemplary lateral cross sectional view of an alternative implementation of the disclosed flotation device before and after activation respectively;
(5) FIGS. 4A, 4B and 4C show exemplary details of alternative reaction chambers and activation mechanisms of the device of FIGS. 3A and 3B;
(6) FIG. 5A shows a schematic cross sectional view of another exemplary implementation of the disclosed flotation device, and FIGS. 5B and 5C show a detailed close up of the inner reaction chamber of the device of 5A before and during activation. FIG. 5D is a schematic drawing of an alternative implementation of the presently disclosed device having a pointed element within the reaction chamber;
(7) FIGS. 6A to 6H show a duckbill valve as an exemplary structure for the passageway connecting the reaction chamber to the inflatable compartment, such a structure being compatible with all of the disclosed implementations of the flotation device;
(8) FIGS. 7A, 7B and 7C show further alternative implementations of the presently disclosed flotation device having alternative expandable structures and activation mechanisms;
(9) FIGS. 8A to 8D are schematic drawings that show a method of using another exemplary device of the present disclosure to fill the inner compartment with water and activate the device; and
(10) FIGS. 9A and 9B show two exemplary alternative closed capsules containing reactant to be housed within the reaction chamber of the flotation device, and FIGS. 9A.1 and 9A.2 show two alternative structures of the capsule of 9A after activation of the flotation device.
DETAILED DESCRIPTION
(11) Reference is first made to FIGS. 1A and 1B, which show conceptually, schematic cross sections of an exemplary flotation device of the present disclosure, before and after activation respectively. The exemplary device has an inner reaction chamber 10 and an outer inflatable compartment 11 surrounding the reaction chamber, which are connected by a passageway 16. The device may be incorporated into an article of clothing or a dedicated belt or backpack or arm-sleeves which would be worn by the user, to provide conveniently wearable devices, such that deployment, when required, will be simple and accessible.
(12) As shown in FIG. 1A, the inner reaction chamber is divided into two sections 13 and 14, each holding a different chemical compound that are capable of generating gas when mixed. One compound may be an acidic material (for instance, phosphoric acid —H.sub.3PO.sub.4, hydrochloric acid —HCl, citric acid —C.sub.6H.sub.8O.sub.7 or others), with the other a basic material, i.e., having a pH above 7.0 (for example, sodium hydrogen carbonate —NaHCO.sub.3). Prior to activation, the reactants 13 and 14 are separated by a removable or modifiable barrier. When the device is activated, which may be performed by pulling off separator 15, or by various alternative mechanisms of removing or modifying the barrier as will be discussed further herein below, the chemical compounds 13 and 14 are mixed in the reaction chamber 10, causing a chemical reaction that creates a gas, for instance, carbon dioxide when using a bi-carbonate base. During the reaction phase, both chemical compounds are essentially prevented from exiting the reaction chamber 10 and are kept in contact, rather than being allowed to disperse into the inflatable compartment 11, in order to allow close to full completion of the reaction. The chemical reaction between the two reactants 13 and 14 in the inner reaction chamber 10 thus occurs efficiently and in the shortest time possible.
(13) As shown in FIG. 1B, the gas produced from the reaction emerges through a designated passageway 16 from the reaction chamber 10 to the outer compartment 11. Such a passageway may be a valve or a thin “tail”. Alternatively, gas may emerge through a semi-permeable membrane permitting only gas through, but preventing any of the chemical compound solution to pass. This membrane implementation may be most easily implemented by constructing the reaction chamber walls of such a membrane material. In another alternative implementation, a duckbill valve is used to separate between the inner and outer compartments, as will be described in accordance with FIGS. 6A to 6H.
(14) For a typical adult sized inflation chamber, the current device may hold approximately 75 ml of acid, base, and water which should allow the creation of 5 to 7 liters of gas. The corresponding weight of about 75 g can easily be carried by most swimmers, yet provides a sufficient amount of gas for adequate inflation capabilities in the event of need.
(15) The inflatable chamber 11, generally the outer compartment, is sealed and designed to contain the gas originating from the chemical reaction occurring in the inner device. When the inflatable compartment inflates, it supports the swimmer such that his head can remain above water. It is to be understood that the term “inflatable chamber” may be a single component or may comprise multiple fluidly connected sections for increased comfort such as is typical in wearable flotation devices. However, in such a case of a device having multiple sections, it is to be understood that these sections are configured to be inflated with gas and that none of these sections comprise any reactants, nor does the chemical reaction occur in any of these sections.
(16) Reference is now made to FIGS. 2A to 2C which show isometric, schematic views of an exemplary flotation device before, during, and after inflation respectively. As shown in FIGS. 2A and 2B, the inner compartment 21 is folded within the outer compartment 22. A closure seal 20 separates the different reactants within the inner reaction chamber. Once the closure seal 20 is removed, as shown in FIG. 2B, the reactants may mix, generating the gas which inflates the device, allowing it to unfold as shown in FIG. 2C.
(17) Reference is now made to FIGS. 3A and 3B which show lateral cross-sectional views of another exemplary flotation device before and after activation, respectively. As shown in FIG. 3A, the inner reaction chamber 30 has a compact form prior to activation and is contained within the outer inflatable compartment 31. The inner reaction chamber 30 houses the gas producing reactants, with each of the reactants being separated from each other by one or more barriers (not shown). The flotation device may be activated manually by pulling cords 34 and 35 in opposite directions simultaneously, as shown by the two directional arrows in FIG. 3A. This action removes the barriers and causes the chemical reaction between the reactants to commence. As a result of the sequence of manual activation and the chemical reaction, the inner reaction chamber achieves an expanded form, as shown in FIG. 3B. The gas created from the chemical reaction escapes through the passageway 32 into the outer inflatable compartment 31, inflating the device. The passageway 32 may be a one-way passageway that provides substantially preferential passage of the gas over the reactants, and should be pressure sensitive. Such a passageway may be, inter alia, a duckbill valve, a semi-permeable membrane or a “tail”. The device may further comprise a handle 33 for the user to grip to support himself more easily, and to prevent the device from floating away from the user, in those cases where the device is not incorporated into an article worn by the swimmer. The details of the inner reaction chamber structure and alternative activation mechanisms are shown in exemplary FIGS. 4A to 4C below.
(18) Reference is now made to FIGS. 4A to 4B which show exemplary alternative cross-sections of the flotation device shown in FIGS. 3A and 3B, having different reaction chamber structures. FIG. 4C shows an alternative implementation having yet another reaction chamber structure and activation mechanism.
(19) Reference is first made to FIG. 4A, which shows the flotation device prior to activation. The reaction chamber is housed inside the outer inflatable chamber 40 and comprises two compartments 41 and 42 positioned at opposite ends of the inflatable chamber, each housing a different reactant. For example, compartment 41 may house an acid and compartment 42 may house a base. The compartments are connected by a flexible walled tube 45 which is clamped such that the reactants cannot mix, but are able to mix when the tube clamp is removed and the tube can expand. Clamping structures 44 and 49, apply pressure to compress the tube 45 prior to activation of the device, to a sufficient degree to prevent mixing of the reactants. The manual activation cords 47 and 48 are each connected to the clamping structures 44 and 49, and may be pulled in opposite directions simultaneously as shown by the arrows in FIG. 4A. This action pulls the clamping mechanisms 44 and 49 away from the collapsible tube 45, allowing the tube to expand and straighten. Once the compartments 41 and 42 are fluidly connected, the reactants may mix and the gas producing chemical reaction begins. The produced gas then flows through a passageway, shown in FIG. 4A as a spout 32, into the inflatable compartment 40, inflating the device. The mixing tube 45 and the spout 32 should be of dimensions commensurate with the flow required of the fluids within.
(20) Reference is made to FIG. 4B which shows an alternative implementation of the reaction chamber. In this implementation, the reaction chambers 41 and 42 are positioned on the same side of the inflatable chamber, and the compressed flexible tube 45 makes a single U-turn around the clamping elements 44 and 49. An additional clamping element 46, may be used if the two elements 44 are separate pieces, instead of a U-clamp around both top and bottom of the element 49. The device is activated in the same manner as that of FIG. 4A. However, in this alternative reaction chamber structure, a further alternative construction feature is shown, in that the walls of compartments 41 and 42 are made of a gas permeable membrane that does not allow liquid reactants to pass through. The gas produced from the reaction passes through the membrane and into the outer inflatable chamber 40, inflating the device, while the liquid reactants are kept within the reaction compartments 41, 42.
(21) Reference is made to FIG. 4C which shows yet a further exemplary implementation, in which the compressed connection tube 45 is simply clamped onto the central clamp block 49 by an external U-element 43, which, when pulled off the central block 49, enables the reactants to mix.
(22) FIGS. 4A to 4C represent only three possible examples of how the reactant chambers are held separately and how the reaction activation takes place, but are not meant to limit the invention, and it is understood that many other configurations can be devised.
(23) Reference is now made to FIGS. 5A to 5C which illustrate schematically an alternative construction for the devices of this application, using structures similar to blister packs of pharmaceuticals to keep the reactants separate. FIG. 5A shows a cross sectional schematic view of the complete flotation device, and FIGS. 5B and 5C show a detailed close up of the inner reaction chamber of the device before and during activation respectively. Reference is made to FIG. 5A, which shows the inner reaction chamber 50 housed within the outer inflatable compartment 51. A plurality of blisters 53, or alternatively elongated blister-like tubes, are spaced throughout the reaction chamber 50 that comprise a reactant compound B, for example a base. Another reactant, compound A, for example an acid, is stored in the spaces between the blisters or tubes 53. In the simplest implementation, either reactant A or B is an aqueous solution. Alternatively or additionally, water may be provided for the reaction through a one-way valve as will be shown in FIGS. 8A to 8C. Reactants A and B are gas producing reactants; however, the blisters 53 are not permeable to compound A, such that the compounds are not mixed prior to activation of the device.
(24) Reference is made to FIG. 5B, which shows a detail of the reaction chamber 50 prior to activation. A removable layer 52 is positioned such that it is in contact with the top of the blisters 53, sealing the blisters and preventing compound B from exiting the blisters.
(25) Reference is made to FIG. 5C, which shows how the device is activated by pulling off the removable layer 52 covering the blisters or tubes containing compound B. The layer may be pulled off by manually by the user, such as pulling a cord attached to the layer. This action removes a portion of the surfaces of the blisters 53 and allows compound B to exit the blisters, hence exposing compound B to the surrounding compound A. This exposure commences the gas producing reaction, and the gas exits the inner reaction chamber through a passageway 32, such as a valve, or through the membrane walls, inflating the outer compartment 51 with gas.
(26) Reference is made to FIG. 5D, which shows an alternative exemplary reaction chamber structure. The reaction chamber 54 is divided into two separate sub-compartments 56 and 57 by means of a dividing sheet of a material 59 that can be readily punctured or slit. The first compartment 56, incorporates a pointed element 58, whose tip is directed towards the dividing sheet. On the other side of the dividing sheet, there is a second sub-compartment 57. The two reagents for generating the inflation gas are contained in the two separate sub-compartments on either side of the dividing sheet 59. Activation of the device causes the pointed element 58 to penetrate the dividing sheet, thereby enabling the reactants to mix and to generate the inflation gas. Either or both of the sub-compartments may have a passageway 32 that is configured to allow the passage of produced gas into the outer inflatable compartment 55.
(27) In this implementation, the device may be activated manually, such as by pulling a cord 60, which may be attached to the pointed element 58, or to a structural part of the reaction chamber to which the pointed element is attached. One of the sub-compartments may contain a liquid reactant, such as an acidic solution, and the other may contain a solid or aqueous solution of the second reactant, which in this example would be a gas producing base.
(28) Reference is now made to FIGS. 6A to 6H, which show exemplary configurations of the passageway 32 of any of the above described implementations. As described above, the passageway should have special properties, including being pressure sensitive, and optionally also being uni-directional and providing substantially preferential passage of gas over reactants, to prevent the reactants from exiting the reaction chamber before the reaction is in the advanced stages. FIG. 6A shows the implementation of FIG. 2B again, with the passageway (not visible in the drawing) situated within the fold of the walls of the device before deployment. although the passageway may be located anywhere between the reaction chamber and the inflatable compartment.
(29) Reference is made to FIG. 6B which shows an exemplary “tail” which effectively acts as the passageway. Another exemplary configuration of the passageway is shown in FIGS. 6C and 6D. FIG. 6D shows a pressure sensitive passageway 61 prior to opening, and FIG. 6C shows the passageway 62 after activation of the device. As gas flows downwards toward the opening 61, pressure acts on the top of the valve 62, causing the valve 61 to open and allowing gas to flow from the inner reaction chamber to the outer inflatable chamber.
(30) Reference is now made to FIGS. 6E to 6G which show an especially advantageous implementation having a pressure sensitive duckbill valve located between the reaction chamber and the inflatable chamber (not shown). As shown in FIG. 6E, when the device is not activated, the duckbill valve is closed and does not allow passage of reactants into the outer inflatable compartment. FIG. 6F shows how external pressure keeps the duckbill valve closed. FIG. 6G shows how the duckbill valve opens under the influence of internal pressure. As gas is created within the reaction chamber, this creates internal pressure on the duckbill valve and when this pressure reaches a predetermined level, the valve opens. The valve may be structured to open at a designated pressure that can only be achieved when the reaction is in the final stages, so as to avoid any significant leakage of reactants into the inflatable chamber prior to virtual completion of the reaction. FIG. 6H shows isometric views of exemplary duckbill valves.
(31) Reference is now made to FIGS. 7A to 7C, which show alternative structures of the flotation device and their respective activation mechanisms. Reference is made to FIG. 7A, showing a flexible locking seal 70 separating the compartments housing the different reactants. When the device is activated, the seal opens and the device unfolds as shown by the directional arrows. FIG. 7B shows an alternative structure of the device prior to activation, and the directional arrows show how the device unfolds upon activation. FIG. 7C shows an alternative configuration of the device having the reaction chamber 72 located on the outside of the device, and the inflatable reaction chamber 73 on the inside. The device may be activated by removing the closure seal 71, resulting in a chemical reaction and inflation of the device. The device is unfolded according to the directional arrows shown.
(32) FIGS. 8A, 8B and 8C schematically show an alternative implementation of the device, in which the reactants are carried in solid form or as highly concentrated fluids and the water for enabling the reaction is drawn from the user's surroundings. The device can then be significantly smaller and lighter than the previous embodiments in which an aqueous solution of either the acid or base needs to be carried. Consequently, the device can be worn for example on the wrist similar to wristwatch or as a belt around the waist, causing negligible interference to the swimmer. Furthermore, at least in the case of both reactants being in solid form, since no reaction can take place in the absence of water, the two reactants can be mixed in a single chamber, thereby simplifying the device. This implementation has a one-way valve for drawing in water from the user's surroundings, for use in the chemical reaction that creates the gas. Any type of water, including fresh water or sea water, may be used.
(33) Reference is now made to FIG. 8A, which shows a schematic representation of the device prior to activation. The reaction chamber 80 may be made up of two separate compartments, 81, 82. Compartment 81 may be a sealed dry storage container that houses both solid reactants, and compartment 82 is configured to collect a predetermined amount of water that is drawn in through a one-way valve V1 as the user is swimming. The collection of water is shown by the directional arrow in FIG. 8A. The water level is shown by the hatched area at the bottom half of the compartment. The function of an optional valve V2 is described hereinbelow. Valve V3 is situated between compartments 81 and 82. An empty plastic bag 84 is provided to contain the gas produced as described herein below.
(34) Reference is now made to FIG. 8B, which shows compartment 82 full with the desired amount of water needed for the reaction, ready to be mixed with the dry reactants in compartment 81 to generate the flotation gas.
(35) Reference is now made to FIG. 8C, which shows how the chemical reaction is activated by the user. By pulling the activation handle, valve V3 between the compartments 81 and 82 is opened, and the water charge in compartment 82 is allowed to mix with the dry reactants in compartment 81. The mixing of the water with the solid reactants enables the chemical reaction which generates the inflation gas, which flows through a pressure sensitive, one-way valve of the type described in the previous embodiments, indicated in FIG. 8C by the arrow 85 between the reaction chamber 80, and a plastic inflation bag 84, thereby filling the bag 84 with the flotation gas, while the reaction is constrained within the reaction chamber 80.
(36) There are a two possible implementations of the device, depending on how it is intended to be used. According to a first, and probably more convenient implementation, the activation trigger causes two separate actions to occur. Valve V1, which enables entry of the sea or fresh water into the water container 82, is opened, thereby charging the reaction chamber with water, and at the same time valve V3 is opened, thereby allowing the water charge to mix with the dry reactants and to generate the inflation gas. This implementation has the advantage that until activated, the device does not contain any water, thereby contributing to its lightweight and convenient form.
(37) According to a second implementation, the water entry valve V1, is activated by the user as soon as he/she enters the water, such that the water charge is ready for use in case of an emergency. Activation then only involves opening valve V3 to allow the pre-charged water to mix with the dry reactants and to generate the inflation gas. This implementation, though less convenient, since the swimmer has to wear the device with its water charge, even though that charge is only on the order of 75 g, has the advantage that the water charge can be collected at a time when no emergency is being experienced, such as when entering the sea to swim. In that case, the user has sufficient presence of mind to ensure that the water intake opening is below the water level of the sea. This may not be so certain with the previous first implementation, where water intake is only performed when the activation mechanism is triggered at the time of an emergency. An optional additional valve V2 may be located on compartment 82 for draining the water charge from the device when the user has finished swimming. Therefore, if the reaction has not been activated, draining of the water charge from the device through valve V2, enables the device to be dried out and used again.
(38) Reference is now made to FIG. 8D, which shows a schematic drawing of an alternative structure for the devices of FIGS. 8A to 8C, in which only a single reaction chamber 80 is used, with both of the solid reaction components stored therein, and in which the reaction is instigated by actuation of a single valve V4, which enables entry of water from the outside when the activation mechanism is triggered at the time of an emergency. Once the gaseous products of the reaction are generated, they flow into the plastic inflation bag 84 through a one-way valve, as in the previously described implementations. The advantages of this device is that the construction is simpler, having only a single chamber, 80, and a single actuation valve V4, together with the one-way valve for inflating the flotation bag 84, and that the device is compact and light since it does not need to carry any water. The disadvantage of this embodiment, is that after actuation of the emergency trigger, the swimmer must wait while the reaction chamber fills with water for the gaseous flotation fill to be generated for passage to the flotation bag 84.
(39) Reference is made to FIGS. 9A and 9B, which show two alternative closed exemplary capsules containing reactant that may be located inside the reaction chamber, and FIGS. 9A.1 and 9A.2 show two alternative structures of the capsule of 9A after activation of the device. The capsule of FIG. 9A is an acid-resistant plastic capsule containing a base in solid form, such as a powder, and having a score-line for opening. When the device is activated, the capsule may open along the score-line to achieve the structure shown in FIG. 9A.1, in which the halves of the capsule are still connected, or to the structure shown in FIG. 9A.2, in which the halves of the capsule are completely disconnected. When the capsule is open, the base within the capsule may come into contact with an acid in the reaction chamber around the capsule, causing a gas producing reaction. FIG. 9B shows an alternative capsule structure containing a solid base and having surface pores covered with polymer that react with acid, water, or both. When the device is activated, acid or water comes into contact with the polymer, and the polymer dissolves, causing the pores to be exposed and allowing the acid and base to react. Once the reaction has taken place, the inflation gas generated within the reaction chamber can pass through a pressure sensitive valve, of any of the types previously described, and to fill the inflation chamber, as in the previously described devices.
(40) In any of these implementations, a depth sensor or pressure sensor (e.g., an ultrasonic sensor) may be connected to the inflation device, such that when the sensor reaches a predefined depth, it automatically activates the inflation device. This enables automatic activation of the device if the swimmer sinks into the water. Alternatively or additionally, any suitable simple manual activation mechanism, such as a lanyard, a handle, a lever, or tearing a seal, may be used to initiate a chemical reaction, thus activating the device.
(41) It is appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of various features described hereinabove as well as variations and modifications thereto which would occur to a person of skill in the art upon reading the above description and which are not in the prior art.
