EP0079956A1

EP0079956A1 - Liquid-sensitive actuator for displacement-responsive devices

Info

Publication number: EP0079956A1
Application number: EP19820902142
Authority: EP
Inventors: Steven A. Becnel
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-05-27
Filing date: 1982-05-27
Publication date: 1983-06-01
Also published as: WO1982004232A1

Abstract

Un dispositif d'actionnement sensible au liquide permet l'actionnement d'un dispositif sensible au deplacement, tel qu'un dispositif de flottaison gonflable. Le dispositif d'actionnement comprend un organe de detection (42) dans une enceinte (44) qui se dilate au contact d'un liquide pour communiquer un deplacement au dispositif et par consequent le mettre en action. Dans le cas d'un dispositif de flottaison, l'actionnement peut comprendre le deplacement d'un organe de detente (106) pour provoquer la decharge gazeuse d'une cartouche (6) et deployer une cellule gonflable (c). L'organe de detection peut comprendre un organe a eponge naturelle seche, comprimee (42) qui se dilate de maniere rapide et forcee lorsqu'elle est immergee dans l'eau pour actionner le dispositif.An actuation device sensitive to liquid allows the actuation of a device sensitive to displacement, such as an inflatable flotation device. The actuation device comprises a detection member (42) in an enclosure (44) which expands on contact with a liquid to communicate a displacement with the device and consequently to put it into action. In the case of a flotation device, the actuation may include the displacement of a expansion member (106) to cause the gas discharge of a cartridge (6) and deploy an inflatable cell (c). The sensing member may include a dry, compressed natural sponge member (42) which expands rapidly and forcibly when immersed in water to actuate the device.

Description

LIQUID-SENSITIVE ACTUATOR FOR DISPLACEMENT-RESPONSIVE DEVICES

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to liquid-sensitive actuators for actuating devices upon immersion in a liquid and, more particularly, to a liquid-sensitive actuator for causing a physical -displacement or movement to which a device to be actuated is responsive.

2. Description of the Prior Art

Various types of liquid-sensitive actuators are described in the prior art. These are used to produce a response to the presence of a liquid. Typically, the response may be the triggering of an alarm, the starting of a pump or the deployment of an inflatable flotation device, such as a life vest, raft, or the like.

In flotation device applications, at least one inflatable envelope or cell is coupled to and inflated by carbon dioxide gas which is released from a conventional CO₂ cartridge when the device is immersed in water. Typically, a piercing pin is driven forward into the sealing diaphragm at the end of the CO₂ cartridge to permit the escape of gas from the cartridge through a conduit or channel into the inflatable cell. In some, the piercing pin is spring-loaded and retained in a retracted position by a water soluble element. Contact with the water dissolv-es the element and permits the spring to drive the piercing pin forwardly into the cartridge diaphragm. In others, a battery-activated explosive squib or charge drives the piercing pin forwardly when detonated. Some of these employ a battery which is not activated until water enters its interior, causing a chemical reaction which generates sufficient voltage and current to detonate the explosive squib. Some batteries of this type operate only in salt water. Other detonator-type devices use an immersion switch to close a circuit through the salt water itself when the switch contacts are immersed. Still others use pressure-actuated switches which close the circuit when the switch is submerged to a predetermined depth.

In substantially all of these flotation devices, a manual backup actuator is provided for inflating the device should the automatic features of the device fail. It has been found that most of the prior art devices have required unaceeptably high reliance on the manual backup actuator because of frequent failure of the automatic system, or excessively slow reaction time to immersion. Unfortunately, failures or slow reactions of the automatic systems have resulted in numerous deaths and injuries of, for example, aviators or seamen who, due to trauma suffered during an accident or other unfortunate event, are unconscious at the time they enter the water and cannot manually actuate the flotation deviees themselves. Many of the prior art devices also suffer from a high rate of premature actuation and deployment due to undesirably high sensitivity to ambient humidity. Premature actuation can often dangerously interfere with critical tasks being performed by personnel wearing these deviees. An urgent need, therefore, exists for a liquid-sensitive actuator which will respond rapidly upon immersion in a liquid, especially for use in flotation deviees designed to preserve life, yet will not prematurely actuate such deviees by responding to damp atmospheric conditions, even over extended periods.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to obviate the above-noted shortcomings and disadvantages of the prior art by providing a simple, compact, reliable and fast-acting liquid-sensitive actuator for devices which are intended to respond to liquid immersion. Another object of the invention is to provide such an actuator which is sensitive to immersion in many different types of liquids, and does not rely on the electrical conductivity of any particular liquid for its actuation. Another object of the invention is to provide such an actuator which will cause actuation only upon immersion in a liquid, so that premature and unwanted actuation is prevented.

Another object of the invention is to provide such an actuator which can easily and inexpensively be reconditioned for reuse. Another object of the invention is to provide such an actuator which is fully compatible with existing hardware for flotation devices and the like.

These and other objects of the invention are accomplished by providing a liquid-sensitive actuator for actuating a displacement- responsive device upon immersion of the actuator in a liquid, the actuator comprising a housing, inlet means for, admitting liquid into the housing when the housing is immersed in the liquid, and sensing means within the housing adapted to be operatively coupled to the displacement responsive device. The sensing means is expandable upon contact with the liquid to impart displacement to and actuate the displacement responsive device.

The invention also encompasses a liquid-activated device including an electrically responsive element to be electrically energized and switch means operatively connected to the element. The switch means has a first non-energizing state, a second energizing state and a displaceable trigger member for changing the state of the switch from the first to the second state when the trigger member is displaced. The device includes a liquid-sensitive actuator for causing displacement of the trigger member upon immersion of the actuator in a liquid. The actuator comprises a housing, inlet means for admitting liquid into the housing when the housing is immersed in the liquid, and sensing means within the housing operatively coupled to the trigger member. The sensing means is expandable upon contact with the liquid to displace the trigger member and energize the electrically responsive element. The invention also includes a liquid-activated device for discharging fluid from a container, the device having discharge means, including a displaceable trigger member, for discharging fluid from the container when the trigger member is displaced. The Device includes a liquid sensitive actuator for causing displacement of the trigger member upon immersion of the actuator in a liquid, substantially as set forth above. The invention also includes a liquid-activated inflator for mating a gas cartridge having a sealing diaphragm to an inflatable cell. The inflator has piercing means, including a displaceable trigger member, for piercing the sealing diaphragm and venting gas from the cartridge when the trigger member is displaced, and a conduit for directing vented gas to the inflatable cell. The inflator includes a liquid-sensitive actuator for causing displacement of the trigger member upon immersion of the actuator in the liquid, substantially as set forth above.

The invention also includes a flotation device having an inflatable flotation cell and a liquid-activated inflator in fluid communication with the cell for delivering gas to the cell from a gas cartridge having a sealing diaphragm. The inflator has piercing means, including a displaceable trigger member, for piercing the sealing diaphragm and venting gas from the cartridge to the cell when the trigger member is displaced. The flotation device includes a liquid-sensitive actuator for causing displacement of the trigger member upon immersion of the actuator in a liquid, substantially as set forth above. BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set out with particularity in the appended claims, but the invention will be understood more fully and clearly from the following detailed description of the invention as set forth in the accompanying drawings, in which:

Figure 1 is a side elevational view, partly in section, of an inflator coupled to a flotation device incorporating one form of actuator according to the invention;

Figure 2 is a sectional view of the same;

Figure 3 is a sectional view of the same taken along line 3-3 of Figure 2;

Figure 4 is .an exploded view of a portion of the inflator of Figures 1, 2 and 3;

Figure 5 is a schematic circuit diagram illustrating the electrical operation of detonator-type devices incorporating the actuator of the invention;

Figure 6 is a sectional view of a modified form of inflator utilizing a remotely mounted actuator to trigger several inflators of this type;

Figure 7 is a sectional view of the same taken along line 7-7 of Figure 6;

Figure 8 is a sectional view of a modified form of actuator according to the invention, used to actuate a number of remotely mounted detonator-type inflators;

Figure 9 is a sectional view thereof taken along line 9-9 of Figure 8;

Figure 10 is a sectional view of another form of inflator according to the invention;

Figure 11 is a sectional view thereof taken along line 11-11 of Figure 10;

Figure 12 is a sectional view of yet another form of actuator according to the invention; Figure 13 is a sectional view thereof taken along line 13-13 of

Figure 12; and

Figure 14 is a sectional .view of still another form, of inflator according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the description that follows, the liquid-sensitive actuator according to the invention is described as being used in connection with a life vest type of flotation device inflatable by gas from a CO₂ cartridge. It is to be understood, however, that the actuator is capable of being used to deploy other types of flotation devices such as rafts or buoys, to cause inflation of other devices, to actuate electrical circuitry and/or mechanical mechanisms, and in general to produce any type of desired response upon immersion of the actuator in a liquid.

Figures 1, 2, 3 and 4 illustrate one form of inflator for a life vest incorporating the actuator of the invention. The inflator comprises a body 102 machined from aluminum or other suitably durable material. Aluminum is preferred for lightness, but materials such as brass or steel also are suitable. Body 102 could even be fabricated of high-impact plastic. The right-hand end of body 102 has a cavity 104 in which a rocker arm 106 is pi vo tally mounted about a pin 108. Pin 108 is supported in holes 110 in the sides of body 102. Spacers 112 (Fig. 4) on pin 108 flank rocker arm 106 to center it on pin 108. The top portion of rocker arm 106 is provided with an enlarged pad 114 which faces to the left, while the lower portion of rocker arm 106 is provided with an enlarged pad 116 facing to the right. The right-hand end of cavity 104 is closed by a slotted plate 118 which is ret^ned in position by four cap screws 120 received in threaded bores 122 in body 102.

Upper pad 114 faces the end of an upper detonator bore 124 in body 102. The left-hand end of bore 124 has an enlarged, threaded portion 126. A detonator assembly 128 is threadably received within bore 124. A sealing gasket 158 is disposed between detonator assembly 128 and the shoulder of bore 124. Detonator assembly 128 comprises an externally threaded sleeve 130 having an internal bore 132 in which a piston 134 is slidable. Piston 134 has an annular groove 136 in which an O-ring seal 138 is retained. Piston 134 also has a central bore 140 which opens to the left-hand end of the piston and also to its periphery near its right-hand end to form an exhaust port 142, the function of which is described below.

A detonator 144 is installed at the left-hand end of bore 132. Detonator 144 comprises an electrical resistance element 146 connected between electrodes 148. Electrodes 148 are connected to electrical leads 150, 152, which emerge through an opening 154 in the left-hand end of sleeve 130. Resistance element 146 is surrounded by a charge of ignitible, explosive material 156, such as gunpowder. Detonator 144 may conveniently be, for example, a 1.5 volt, 15 milliampere light bulb with the glass envelope removed.

A lower bore 160 is formed in body 102. The left end of bore 160 h-as an enlarged threaded portion 162 adapted to receive a pressurized gas cylinder G, such as a CO„ cartridge. A sealing gasket 164 is disposed between cartridge G and a shoulder in bore 160. Cartridge G has a puneturable sealing diaphragm 166 through which gas is dispensed when punctured. Cartridge G is retained in position by a set screw 168 threadably received in body 102. Cartridge piercing means comprising a piercing pin 170 is slidable within bore 160. Pin 170 has an annular groove 172 in which an O-ring 174 is retained. O-ring 174 prevents the escape of gas through the right-hand end of bore 160. Pin 170 also has a return spring 176 which engages a shoulder 178 on pin 170 to forcibly eject pin 170 from sealing diaphragm 166, once it is punctured, and permit gas to escape from cartridge G.

Gas emerging from catridge G is delivered to inflatable cell C through an internal bore 180 in body 102, which communicates with the interior of a hollow threaded nipple 182. Nipple 182 is bolted (183) or otherwise sealingly secured to cell C so as to communicate with the interior of the cell. Body 102 has a hole 190 which is adapted to receive nipple 182. The inflator is retained in position on nipple 182 by a cap nut 184 positioned in a recess 186 in the face of body 102. A sealing gasket 188 prevents the escape of gas between body 102 and cap 184, while a gasket 189 prevents the escape of gas between nipple 182 and nut 182. A conventional one-way valve, such as a tire stem valve (not shown) may be retained in the interior of nipple 182 to prevent the escape of gas from cell C once it has been inflated. One side of nipple 182 has a flat surface which is adapted to key with a mating flat surface of hole 190 in order to properly orient the inflator.

A mechanism is provided for manual puncturing of sealing diaphragm 166 in the unlikely event that automatic actuation does not occur, or for the purpose of inflating cell C prior to entering a body of water. The device comprises an L-shaped lever 192 which is pivoted about a pin 194 retained in holes 196 in the sides of body 102. Spacers 198 flank lever 192 to center it on pin 194. The end of lever 192 within cavity 104 is adapted to bear against pad 116 of rocker arm 106 when the opposite end of lever 192, which is exterior to body 102, is rotated by a pull on cord 197. Lever 192 is retained in the position shown by a frangible safety wire 199 which couples lever 192 to body 102. Safety wire 199 is designed to break when cord 197 is pulled firmly.

The left-hand end of body 102 has a cylindrical battery chamber 2 which is lined along its bottom and sides by a thin insulating material 4. Battery chamber 2 is sized to receive two silver oxide batteries 6 in series, each having a rating of approximately 1.5 volts. Other types and sizes of batteries may, of course, be used, but silver oxide batteries are preferred for their small size, lightness and long shelf life. An insulating cap 8 made of plastic or the like is secured to body 102 by screws 10. The interior of cap 8 is provided with a conductive terminal 11 which is connected through a hole in cap 8 to electrical lead 152. The opposite terminal within battery chamber 2 comprises a conductive strip 14 at the bottom of chamber 2 which extends through the wall of body 102 and is secured to connecting post 16.

The liquid-sensitive actuator for this inflator comprises a housing 20 made of plastic or the like which is secured at one side to body 102 by screws 22 extending through apertures in tabs 24. The opposite side of housing 20 is secured to body 102 by engagement of a set screw 26 with terminal post 16. A switch chamber 28 is disposed at the lower side of the housing and includes a lower contact 30 connected to terminal post 16 and a separate upper contact 32 borne by a metallic leaf spring 34. Leaf spring 34 is connected to electrical lead 150 through a terminal screw 36. Leaf spring 34 serves as a displaceable trigger member which is moved by the actuator, as described below, to cause inflation of cell C.

Within housing 20 is a follower means which comprises a displaceable plate 38 and a coupling rod 40 attached thereto. Rod 40 bears against leaf spring 34. Plate 38 is retained in its initial, undisplaced position by the resiliency of spring 34. A sensing means in the form of an expandable member, such as a dried, compressed natural sponge 42 is disposed between plate 38 and the upper wall 44 of housing 20. Wall 44 is provided with apertures 46 through which liquid can enter housing 20 when immersed in a liquid. Additional apertures (not shown) are provided in the front wall of housing 20.

In operation, when the inflator, and particularly housing 20, is immersed in water, sponge 42 rapidly absorbs water and expands, driving plate 38 and rod 40 downwardly against leaf spring 34. Contacts 30 and 32 close, thereby completing a series circuit, illustrated in Figure 5, including batteries 6 and detonator 144. Resistance element 146 rapidly heats and causes charge 156 to explode, thereby driving piston 134 rapidly and forcefully to the right within bore 132. The right-hand end of piston 134 strikes pad 114 of rocker arm 106 and causes rocker arm 106 to rotate clockwise about pin 108 to the position indicated by broken lines in Figure 2. The lower end of rocker arm 106 then forces puncturing pin 170 to the left, piercing diaphragm 166. At this point piston 134 has moved to the position depicted by broken lines in Figure 2, thereby uncovering exhaust port 142. Combustion gases are thereby vented into cavity 104, relieving the driving force on pad 114. Return spring 176 then extracts piercing pin 170 from diaphragm 166, if the pressure of the gas within cartridge G has not already done so, and permits the gas to flow into cell C through bore 180 and stud 182.

Dried, compressed natural spong eis the preferred material for sensing means 42. Such a material is very stable under normal ambient conditions and will not tend to expand even when humidity is somewhat high. If permitted to expand without confinement, the natural sponge would expand to approximately 12 times its original size. The force which drives plate 38 and rod 40 downwardly to close switch contacts 30 and 32 is, therefore, considerable because the space available for travel of plate 38 is only on the order of the initial thickness of the sponge. Sponge 42 expands extremely rapidly upon immersion in water and causes detonation of detonator 144 less than one second after immersion. In fact, detonation times of as low as 0.83 seconds have been experienced, with full deployment (inflation) of life vest cells occurring in less than three seconds.

Other types of expandable materials may be used as sensing means. For example, certain types of compressed paper or synthetic sponges may be suitable. In general, the uneonfined volume expansion of the material should be sufficient to generate an actuating force which will reliably close switch contacts 30, 32, and which will yield a reaction time to detonation on the order of not more than three seconds for a life preserving device. The material must be capable of expanding upon contact with fresh water and salt water, but must not expand merely in the presence of humid air. It can be seen that the inflator of Figures 1-4 is designed for easy and inexpensive reconditioning for reliable reuse. A spent detonator assembly 128 can be unscrewed and replaced by a new one. Similarly, cartridge G, batteries 6 and actuator housing 20 can be easily replaced. The spent detonator assembly 128 can be reconditioned by inserting a new detonator 144. The spent cartridge G can be refilled with CO₂ and resealed. The expanded sponge 42 can be removed and replaced with a compressed sponge. The reconditioned detonator assembly 128, cartridge G and actuator housing 20 can be reinstalled in other inflator bodies 102. Figure 14 illustrates a modified inflator configuration. In this device, body 202 has a bore 204 for piercing pin assembly 206, detonator 208 and CO₂ cartridge G. Detonator 208 has a construction similar to that used in the embodiment of Figures 1 through 4, that is, it includes an electrical resistance element and an explosive charge. Piercing pin assembly 206 has a rear piston 210 and a forward piston 212 secured to a common spindle or stem 214. The force of the exploding charge acting on piston 210 drives piercing pin assembly 206 forwardly. A return spring 216 bears against a shoulder 218 in bore 202, -and an O- ring 220 retained in groove 222 on stem 214 prevents the escape of gas from cartridge G through bore 204. A manual actuator lever 248 is provided which pivots about pin 250 to urge piercing pin assembly 206 to the left by engagement with piston 212. Mo-unting of the inflator on the hollow threaded nipple 224 of an inflatable cell is similar to that in Figures 1 through 4. Above body 202 is a battery and actuator housing 223 dovetailed to body 202 (not shown) and secured by eap screws 225 or the like. Battery chamber 226 houses a 7 volt, 10 milliampere mercury oxide battery 228. One terminal of battery 228 is connected to detonator 208 through lead 230, and the other contact is connected to leaf spring switch contact 232. Stationary switch contact 234 is connected to detonator 208 by lead 236.

Actuator housing 238 has holes 240 through which liquid may enter to expand the sensing means 242 within. The sensing means may comprise a dried, compressed natural sponge or other suitable expandable material, as described above. Plate 244 and pin 246 are driven to the right when sponge 242 expands to close switch contacts 232, 234 and cause detonation of detonator 208.

The liquid sensitive actuator need not be integrally mounted with the detonator or the battery. In some applications, it may be desirable to mount the actuator separately and trigger a plurality of detonator type inflators using a single actuator. Such an arrangement is illustrated in Figures 6 and 7. In each inflator of this arrangement, a body 302 is mounted on a hollow threaded nipple 304 in the manner of the inflator of Figures 1 through 4. Body 302 merely mates the gas cartridge G with the detonator 306. Detonator 306 is similar in construction to the detonator of Figure 14. A piercing pin assembly 308 is slidably received within a bore 310. Piercing pin assembly 308 has the usual return spring 312 and O-ring seal 314. Gas dispensed from cartridge G flows through two bores 318 into hollow nipple 304 and then into cell C. The remotely mounted liquid-sensitive actuator and battery pack are connected in parallel with the inflator assemblies so that they are all detonated simultaneously.

An actuator which is well suited for remote mounting is illustrated in Figures 8 and 9. This actuator has a cylindrical casing 402 which is divided into a switch chamber 404 and a housing 406 for the sensing means. A multiple pole, single throw switch 408 (in this case a triple pole swit.ch for three remotely mounted detonators) is mounted within switch chamber 404. Switch arm 410 is disposed in contact with actuator rod 412, which is attached to follower piston 414. Piston 414 has a peripheral groove, in which an O-ring seal -415 is retained. Above piston 414 is the sensing means 416, which preferably comprises a dried, compressed natural sponge. Apertures 418 in the sidewall of housing 406 are adapted to permit the entry of liquid into the housing. However, a barrier means in the form of a closure member 420 closes off the end of housing 406 and surrounds a portion of the sidewalL Cap 420 is retained on housing 406 for rotatable movement relative to the housing by an interengaging annular rib 422 and groove 424. Similar apentures 426 are formed in the annular wall of cap 420. When cap 420 is in the angular position illustrated in Figure 9, apertures 426 and 418 are not aligned. This configuration will prevent the entry of liquid into housing 406. Twisting cap 420 so that apertures 426 and 418 are aligned will "arm'' the device by permitting entry of liquid into housing 406. Such a feature is therefore very useful in preventing premature expansion of sponge 416 and triggering of the detonators in very damp conditions. A manual actuation mechanism is provided which comprises a link 428 attached to switch arm 410, and a cable 430 attached to the end of link 428. A retaining spring 432 maintains some slack in cable 430 to prevent inadvertent tripping of switch 408 until a positive and firm pull is exerted on cable 430. Figures 12 and 13 illustrate a modified actuator which incorporates a different type of barrier means to prevent premature expansion of the sensing means. A housing 502 contains expandable sensing means 504, follower means 506 and switch contacts 508, 510. Housing 502 is also provided with apertures 512 through which liquid can enter. Housing 502 is surrounded by a chamber 514 having a lower apertured inlet grid 516 and an upper port 518 for exhausting trapped air. Retained within grid 516 and a separate support grid 520 is a mass of filamentary or fibrous material 522, such as rayon staple fibers. Fibrous material 522 effectively prevents the free flow of air into housing 502 to keep the humidity within the housing generally low even in humid ambient conditions.

Figures 10 and 11 illustrate a modified inflator which does not utilize electrical and explosive actuation of the piercing pin, but instead relies on direct mechanieal operation of the expandable sealing means on a spring-loaded triggering device. In this embodiment, a body 602 has an upper bore 604 defining a housing for the sensing means 606, which of course may comprise a dried, compressed natural sponge or the like. A cover plate 608 has an aperture 610 through which liquid can enter housing 604. Other apertures 612 are formed in the sides of body 602. Follower plate 614 is connected to a long actuating rod 616 which protrudes into a cavity 618 formed in the right-h-and end of body 602. A rocker arm 620 is pivoted within cavity 618. A cover 622 and a manual actuating lever 624 with a frangible safety wire 626 are provided as in the embodiment of Figures 1 through 4. A threaded bore 628 is provided at the left-hand end of body 602 for receiving g-as cartridge G, which is retained in place by a set screw 630 and sealed by a gasket 632.

Aligned with bore 628 is a bore 634 in which a spring-loaded firing mechanism 636 and a piercing pin assembly 638 are mounted. Piercing pin assembly 638 has the usual recoil spring 640. The interior of piercing pin assembly 638 has a bore 642 with a tapered shoulder 644. Thrust force for piercing pin assembly 638 is provided by a compressed coil spring 645 which is retained between the rear of piercing pin assembly 638 and a shoulder 647 of firing mechanism 636. Firing mechanism 636 includes a latching device (described below) which holds piercing pin assembly 638, firing mechanism 636 and coil spring 645 together until actuation occurs.

Firing mechanism 636 comprises a shaft 646 integral with a threaded plug 648 which is screwed into the right-hand end of bore 634 and sealed by a gasket 650. A central bore 652 within shaft 646 houses a rod 654 which is spring-biased to the right by a spring 656. Right hand movement of rod 654 is limited by the shoulders 658 of a cap 660. The left portion of rod 654 has a section of reduced diameter 662. Shaft 646 has four circumferentially arranged holes 664 in which balls 666 are retained. When the larger left end portion of rod 654 is located between balls 666, the balls are urged against shoulder 644 to retain piercing pin assembly 638 in position on' shaft 646. However, when cap 660 is depressed by rocker arm 620, the reduced diameter portion 662 of rod 654 moves between balls 666 and permits them to retract, thereby releasing piercing pin assembly 638 and permitting spring 645 to drive the piercing pin forcefully through the seal of gas cartridge G. Vented gas escapes through an outlet 670 in the wall of body 602, and may be delivered to one or more cells or other inflatable devices through conduits 672. As indicated above, the actuator according to the invention is capable of producing any type of desired response upon immersion of the actuator in a liquid. Of course, to be expandable the sensing means must be wettable by the liquid whose presence is to cause actuation. Accordingly, the actuator, and particularly the sensing means may have to be specifically tailored for the expected liquid environment and the desired reaction mode. For example, dried, compressed natural sponge may not be sufficiently wettable by certain liquids, particularly those which are nonaqueous, to expand as desired. The sponse material may, therefore, have to be treated to produce the desired wettability, or a different type of material may have to be used as required. Reaction time is a function not only of material wettability by the expected liquid, but of the volume of material in relation to the space available for expansion as well. If a longer reaction time is desired, such as for devices which are intended to be actuated after a considerable time delay, a less wettable and/or smaller volume of material would have to be selected. Other variations and modifications will be apparent to those skilled in the art without departing from the true spirit and scope of the invention, which is to be limited only by the appended claims.

Claims

1. A liquid-sensitive actuator for actuating a displacement- responsive device upon immersion of said actuator in a liquid, comprising: a housing; inlet means for admitting liquid into said housing when said housing is immersed in said liquid; and sensing means within said housing adapted to be operatively coupled to said displacement-responsive device, said sensing means being expandable upon contact with said liquid to impart displacement to and actuate said displacement-responsive device.

2. In a liquid- activated device including an electrically responsive element to be electrically energized and switch means operatively connected to said element, said switch means having a first nonenergizing state, a second energizing state and a displaceable trigger member for changing the state of said switch from said first to said second state when said trigger member is displaced; a liquid-sensitive actuator for causing displacement of said trigger member upon immersion of said actuator in a liquid comprising: a housing; inlet means for admitting liquid into said housing when said housing is immersed in said liquid; and sensing means within said housing operatively coupled to said trigger member, said sensing means being expandable upon contact with said liquid to displace said trigger member and energize said electrically responsive element.

3. In a liquid-activated device for discharging fluid from a container, the device having discharge means, including a displaceable trigger member, for discharging fluid from said container when said trigger member is displaced; a liquid-sensitive actuator for causing displacement of said trigger member upon immersion of said actuator in a liquid, comprising: a housing; inlet means for admitting liquid into said housing when said housing is immersed in said liquid; and sensing means within said housing operatively coupled to said trigger member, said sensing means being expandable upon contact with said liquid to displace said trigger member and cause said fluid to be discharged from said container.

4. In a liquid-activated inflator for mating a gas cartridge having a sealing diaphragm to an inflatable cell, the inflator having piercing means, including a displaceable trigger member, for piercing said sealing diaphragm and venting gas from said cartridge when said trigger member is displaced, and a conduit for directing ventd gas to said inflatable cell; a liquid-sensitive actuator for causing displacement of said trigger member upon immersion of said actuator in a liquid comprising: a housing; inlet means for admitting liquid into said housing when said housing is immersed in said liquid; and sensing means within said housing operatively coupled to said trigger member, said sensing means being expandable upon contact with said liquid to displace said trigger member and cause gas to vent from said cartridge and inflate said cell.

5. In a flotation device having an inflatable flotation cell and a liquid-activated inflator in fluid communication with said cell for delivering gas to said cell from a gas cartridge having a sealing diaphragm, said inflator having piercing means, including a displaceable trigger member, for piercing said sealing diaphragm and venting gas from said cartridge to said cell when said trigger member is displaced; a liquid-sensitive actuator for causing displacement of said trigger member upon immersion of said actuator in a liquid comprising; a housing; inlet means for admitting liquid into said housing when said housing is immersed in said liquid; and sensing means within said housing operatively coupled to said trigger member, said sensing means being expandable upon contact with said liquid to displace said trigger member and cause said gas to vent from said cartridge and inflate said cell.

6. The invention of claim 5 wherein said piercing means comprises a piercing pin and thrust means for thrusting said piercing pin into said diaphragm when said trigger member is displaced.

7. The invention of claim 6 wherein said thrust means comprises an explosive mechanism adapted to produce a thrust force behind said piercing pin, a battery and a switch in a series electrical circuit, and said trigger member comprises a movable contact of said switch which closes said circuit when displaced by said sensing means.

8. The invention of claim 6 wherein said thrust means comprises a compressed spring urgining said piercing pin toward said diaphragm and latch means for retaining said piercing pin and allowing said spring to thrust said piercing pin into said diaphragm when released, and said trigger member releases said latch means when said trigger member is displaced.

9. The invention of claims 1, 2, 3, 4, 5, 7 or 8 wherein said sensing means is capable of expanding when wet to at least twice its initial size if unconfined by said housing.

10. The invention of claim 9 wherein said sensing means is capable of expanding when wet to at least ten times its initial size if unconfined by said housing.

• 11. The invention of claim 10 wherein said sensing means comprises a dried, compressed natural sponge member.

12. The invention of claim 11 wherein said sensing means causes said displacement and actuation within three seconds of immersion of said housing in said liquid.

13. The invention of claim 12 wherein said sensing means causes said displacement and actuation within one second of immersion of said housing in said liquid.

14. The invention of claims 1, 2, 3, 4, 5, 7 or 8 wherein said sensing means causes said displacement and actuation within three seconds of immersion of said housing in said liquid.

15. The invention of claim 14 wherein said sensing means causes said displacement and actuation within one second of immersion of said housing in said liquid.

16. The invention of claims 2, 3, 4, 5, 7 or 8 further comprising follower means within said housing adjacent said sensing means and operatively coupled to said trigger member, said follower means being displaceable by said sensing means upon expansion of said sensing means to displace said trigger member.

17. The invention of claim 16 wherein said follower means comprises a plate and a connector attached to said plate, said connector extending outwardly of said housing and being operatively coupled to said trigger member.

18. The invention of claim 1 further comprising follower means within said housing adjaeent said sensing means and adapted to be operatively coupled to said displacement-responsive device, said follower means being displaceable by said sensing means upon expansion of said sensing means to impart displacement to and actuate said displacement- responsive device.

19. The invention of claim 18 wherein said follower means comprises a plate and a connector attached to said plate, said connector extending outwardly of said housing and adapted to be operatively coupled to said displacement-responsive device.

20. The invention of elaims 1, 2, 3, 4, 5, 7 or 8 wherein said inlet means comprises barrier means for preventing the free flow of air into said housing to keep the humidity within said housing low in humid ambient conditions and prevent premature expansion of said sensing means, and permitting the entry of said liquid when said housing is immersed therein.

2L The invention of claim 20 wherein said barrier means comprises a mass of filamentary material.

22. The invention of claim 21 wherein said material is rayon.

23. The invention of claim 21 wherein said barrier means comprises closure means movable between a closed position substantially sealing said inlet means to prevent entry of fluid into said housing, and an open position to permit entry of liquid into said housing.

24. The invention of claim 23 wherein said inlet means comprises at least one housing aperture through the wall of said housing, and said closure emans comprises a shutter movable relative to the wall of said housing to either cover or open said housing aperture.

25. The invention of claim 24 wherein said shutter has a shutter aperture therethrough, .said housing and shutter apertures being alignable to permit entry of liquid into said housing, and nonalignable to prevent entry of fluid into said housing.