Fluid pressure sensing devices

[57] ABSTRACT

Disclosed are a fluid pressure sensing device and system for selectively inflating flotation equipment, e.g., life saving vests, jackets, rafts, etc. wherein, when the pressure of the fluid exterior to a fluid pressure sensing member thereof substantially reaches a selected fluid pressure, e.g., two feet of water, a resilient member thereof, e.g., an “0” ring, is forced out of sealing engagement with a geometrically shaped slot selectively formed in the inner wall of the fluid sensing member and fluid, such as water, enters through geometrically shaped openings selectively formed in the bottom wall of the geometrically shaped slot and into a cavity formed in the fluid pressure sensing member; wherein the fluid dissolves a fluid soluble member positioned within said cavity, e.g., a water soluble disc, and thereby releases a gas control or releasing member thereof, e.g., a spring biased slidable shaft having a pointed end thereon; whereby the gas control member moves to its gas releasing position, e.g., the pointed end of the slidable shaft pierces a frangible seal on a CO₂ bottle or cartridge and permits passage of the gas from the gas storing member to the flotation equipment for inflation thereof.

Claims, 12 Drawing Figures

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PATENTEOAPR 9 1974 3,802,012

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?ATENTEO*PR 91974 3^802,012

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FIG. 12

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FLUID PRESSURE SENSING DEVICES

PRIOR ART AND BACKGROUND INFORMATION

There exists a present need for a technically simple, relatively inexpensive, yet highly reliable fluid pressure sensing device for automatically inflating life saving flotation equipments. Skilled artisans in this field of technology have recognized that “wearability” of life saving equipment is an important characteristic, no less important than any other characteristic including “reliability” and “durability”. This is a fundamental truth because the most reliable and durable life saving equipment is ineffectual if the user is not wearing such equipment when an accident or emergency occurs. Such factors as weight, bulk and comfort are important characteristics in whether or not the flotation equipment will be worn by the user. It is an established fact that inflatable life saving equipment per se are more comfortable, weigh less and are less bulky prior to inflation than presently Coast Guard approved conventional foam or kapok filled life saving equipment. However, such conventional equipments have the advantage that the user does not have to do anything but wear the equipment to obtain adequate flotation support during emergencies. Thus, it is a desireable feature that life saving equipment preferably does not require conscious user effort to render such equipment operable prior to emergency use. An inflatable life saving jacket, for example, preferably should be automatically inflated without conscious user participation once the user is immersed in water or quickly thereafter, e.g., within several seconds after water entry, such as twenty seconds or sooner. Water actuated life saving equipment will automatically operate without user awareness within several seconds after water entry but are unsatisfactory because such equipments prematurely operate due to excessive water vapor, moisture accumulation, and water exposure, i.e., when subjected to standing water, splashing, rain, or the like. Accordingly, life saving equipment of the gas inflatable type must be water tolerant during storage and when being worn prior to water emergency, but must automatically operate without user awareness when the user is inadvertently immersed in water by virtue of an emergency. Of course, manual user override of the automatic feature for intentional inflation of the life saving equipment when an emergency is imminent or probable is another desireable feature.

The prior art is replete with water actuated devices for automatically inflating flotation equipment when the device is immersed in water.

One type of water actuated inflation device utilizes water soluble bands which circumscribe the release handle or lever for actuating the device (see U.S. Letters Patent No. 3,266,668, issued Aug. 16, 1966). Another type of water actuated inflation device utilizes restricting members of various shapes and geometries to hold a spring in a compressed position, such restricting members having sufficient strength to hold the compressed spring when dry but loses its strength when wet, whereby when the device is immersed in water the restricting member releases the spring and actuates the device (see U.S. Letters Patents No. 3,490,648, issued Jan. 20, 1970 and No. 3,494,506, issued Feb. 10, 1970). Another type of water actuated inflation device utilizes a water soluble member of various shapes and geometries which has sufficient strength when dry to hold a spring in a compressed state but disintegrates or dissolves when wet so as to release the spring and thereby actuate the device (see U.S. Letters Patent No.

3,526,339, issued Sept. 1, 1970). Another type of water actuated inflation device utilizes a battery operated explosive member, the battery of which when dry does not produce electrical energy but does produce electrical energy when wet, whereupon when the de10 vice is immersed in water, the battery ignites the explosive member which in turn propels a piston that punctures the seal of a gas storage member to thereby actuate the device (see U.S. Letters Patent No. 3,266,669, issued Aug. 16, 1966). Another type of water actuated inflation device utilizes a source of electrical power and a pair of spaced apart conductors which when wet trigger a thyristor switch to close an electric circuit and thereby actuate the device (see U.S. Letters Patent No. 3,426,942, issued Feb. 11, 1969).

Pressure sensitive inflation devices of various constructions have heretofore been made, but in the most part have not been completely satisfactory by virtue of the fact that such prior known devices have been generally complex in construction, expensive to manufac25 ture and generally unreliable, with some of them utilizing battery storage members requiring periodic checks and maintenance to ensure operability. For example, one type of pressure sensitive inflation device utilizes a flexible diaphragm and associated piston which ³⁰ moves proportional with the pressure external to the device until it releases an actuating member which in turn may ignite an explosive charge or close a circuit, the happening of which releases pressurized fluid for inflation or the like (see U.S. Letters Patent No.

³⁵ 3,349,786, issued Oct. 31, 1967). Another example of a pressure sensitive inflation device utilizes a resilient pressure sensitive diaphragm sealed across an opening which stretches upon immersion in water to a predetermined depth so as to release a trigger member and ⁴⁰ thereby actuate the device (see U.S. Letters Patent No. 3,490,649, issued Jan. 20, 1970).

Although the aforementioned prior known techniques and apparatus for automatically actuating inflation devices of various types have been satisfactory in ⁴⁵ many respects, there still remain several unsatisfactory features and functions that have confronted the skilled artisan in the art to which they pertain, such as, device reliability, technical complexity, high maintenance requirements, high manufacturing costs, durability and user “wearability”.

The several embodiments of this invention as hereinafter described advantageously overcome the aforementioned unsatisfactory features and functions in a simple, relatively inexpensive and highly reliable manner, yet advantageously provide a device that is relatively light weight, compact and comfortable.

BRIEF DESCRIPTION OF INVENTION

This invention relates to a fluid pressure sensitive device for selectively controlling the passage of gas from a gas inlet to a gas outlet thereof, and more particularly relates to a fluid pressure sensitive device for selectively inflating flotation equipment, such as, life saving vests, jackets and rafts.

In one embodiment of the invention the fluid pressure sensing device includes: Gas Control Means for controlling the passage of gas from gas storage means

3,802,012 to flotation equipment which is selectively movable into a gas releasing position; Restraint Means including Fluid Soluble Means for selectively inhibiting the Gas Control Means from moving into its gas releasing position; and Fluid Pressure Sensing Means connected to the Gas Control Means for sensing a selected fluid pressure external thereof. One embodiment of the Fluid Pressure Means of this invention includes a main body portion including a cavity which is releasably connected to the Gas Control Means. A geometrically shaped slot is formed in the inner wall of the main body and geometrically shaped openings selectively formed in the bottom wall of the geometrically shaped slot for providing an unimpeded path for fluid flow from the exterior of the Fluid Pressure Sensing Means through the openings and slot to the cavity of the main body portion. Resilient Means are positioned within the cavity of the main body portion in sealing engagement with the geometrically shaped slot for sealing the geometrically shaped openings and inhibiting fluid from entering the cavity of the main body.

By this novel construction, when the pressure of the fluid exterior to the Fluid Pressure Sensing Means reaches a selected fluid pressure, the Resilient Means is forced out of sealing engagement with the geometrically shaped slot, fluid enters the cavity and dissolves the Fluid Soluble Means, which in turn releases the Restraint Means, whereupon the Gas Control Means moves to its gas releasing position and permits passage of gas from the gas storage means to the flotation equipment for inflation thereof.

In another embodiment of the invention, the fluid pressure sensing device includes Housing Means having a geometrically shaped cavity formed therein and a gas outlet and inlet selectively located thereon; Gas Controlling Means for selectively controlling the passage of gas from the gas inlet to the gas outlet which is selectively moveable from a gas inhibiting position to a gas releasing position; Restraining Means for releasibly holding the Gas Control Means in its gas inhibiting position which include a fluid soluble member; Biasing Means for moving the Gas Control Means into its gas releasing position which is restrained from operation by the Restraining Means; Pressure Sensing Means including a pressure sensing head having a central chamber and selectively positioned slots formed therein with associated openings and a resilient member positioned within the slots for sealing the openings and inhibiting fluid from entering the chamber. By this latter novel construction, when the external fluid pressure reaches a selected value, the resilient member is forced out of its sealing position to allow fluid to enter the chamber, whereupon the soluble member dissolves, the Restraining Means releases the Biasing Means and the Gas Control Means is biased into its Gas releasing position, thereby permitting passage of gas from the gas inlet to the gas outlet.

It is contemplated that the resilient member may be of various geometric shapes, such as, ring-like, a solid or hollow sphere, band-like, or a full or partial tube, so long as its shape and resilient characteristics in structural combination with the shape of the slots formed in the inner wall of the pressure sensing head cooperate effectively to seal such slots and the associated openings and inhibit fluid from entering the chamber or cavity thereof until the external fluid pressure reaches a selected value.

OBJECTS OF THE INVENTION

It is one object of this invention to provide a pressure sensing device for selectively allowing gas to pass from a gas inlet to a gas outlet thereof.

Another object of this invention is to provide a fluid pressure sensing device for selectively inflating flotation equipment, such as life saving vests, jackets and rafts, when the device is immersed in water to a selected depth.

Another object of this invention is to provide a pressure sensing device of the type described herein which is uniquely tolerant to water vapor, moisture accumulation, humidity, water exposure, or the like, and only operates automatically when immersed in water and subjected to hydrostatic pressure which is capable of causing operation of the device, such as two feet of water.

Another object of this invention is to provide a pressure sensing device of the type described herein which prevents the passage of gas from gas storage means to flotation means for inflation thereof until the pressure of the fluid exterior to the device reaches a selected hydrostatic pressure.

Another object of this invention is to provide an automatically actuated pressure sensing device of the type described herein that includes a manual override capability for selectively inflating flotation means prior to an emergency condition without adversely affecting the automatic pressure sensing capability of the device.

Another object of this invention is to provide a pressure sensing device requiring relatively fewer pressure sensing members, yet advantageously senses hydrostatic pressures of relatively small pressure differentials.

Another object of this invention is to provide a pressure sensing device of the type described herein which advantageously provides improved “wearability”, yet adequately achieves satisfactory “reliability” and “durability”.

Another object of this invention is to provide a pressure sensing device of the type described herein which is technically simple, relatively inexpensive to make, highly reliable and durable, yet being relatively lightweight, compact and comfortable to advantageously achieve improved user “wearability”.

These and other objects and features of this invention will be readily apparent from the following description when taken in conjunction with the appended claims and attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially cross-sectioned and partially cutaway view of a fluid pressure sensing device for selectively inflating flotation equipment in accordance with one embodiment of the present invention, with the lanyard and manual lever thereof in a manual override position shown in phantom.

FIG. 2 is a perspective view of the clevis and bore plug assembly, manual actuation lever, coaxial sleeve and drive pin and piercing pin of FIG. 1

FIGS. 3-5 are cross sectional views of alternate embodiments of the flexible member of the pressure sensing head in accordance with this invention.

FIG. 6 is a top plan view of the pressure sensing head of FIG. 1.

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FIG. 7 is a cross sectional view of the pressure sensing head taken along the view plane 7—7 of FIG. 6.

FIG. 8 is a cross sectional view of the pressure sensing head of FIG. 7 taken along the view plane 8—8 with the flexible member removed for clarity and graphic simplicity.

FIG. 9 is a perspective view with partial cut-away portions of a subverter cap in accordance with this invention.

FIG. 10 is a perspective view with partial cross section of the pressure sensing head of FIG. 1 with the subverter cap of FIG. 9 secured in its subverting position.

FIGS. 11 and 12 are cut away, partially sectioned views of the flexible member of FIG. 1 respectively in its sealing and non-sealing position.

DETAILED DESCRIPTION

A detailed description of several embodiments of this invention follows with reference being made to the drawings wherein like parts have been given like reference numerals for clarity and understanding of the elements and features of this invention.

Referring to FIGS. 1 and 2, there is generally shown a fluid pressure sensing device for selectively inflating flotation equipment (hereafter PS Device) in accordance with one embodiment of this invention which is readily adaptable for use with a standard inflatable life vest, jacket or raft. The PS device includes a main body portion 10 having a mounting hole 12 of standard shape and dimension for releasably securing the PS device to a standard inflatable life vest, jacket or raft. At one end of the main body 10 is an internally threaded opening 14 for releasably securing a gas storage member 15, such as a standard CO₂ cartridge. To ensure gas sealing integrity between the gas storage member 15 and the internal cavity 16, a gasket 18 is provided which abuts the end wall of opening 14. The other end of the main body 10 has an externally threaded shank 21 upon which is threadably secured an internally threaded bonnet 22.

A clevis and bore plug assembly, generally indicated at 24, is releasably secured within the cavity 16 by the bonnet 22. This assembly includes a clevis 26 having a transverse slot formed at one end, a cross pin 28 for holding a lever 30 in position thereon, a shoulder portion 32 for positioning and clamping the clevis 26 with respect to and upon the main body 10, and a flexible “O” ring seal 34 for preventing egress and ingress of unwanted fluids out of and into the cavity 16. A sleeve 36 having a diameter less than the diameter of the clevis 26 and coaxial therewith is secured to or integral with the clevis 26. Coaxially positioned within the sleeve 36 is a drive pin 38 which is mounted therein for slidable coaxial movement with respect to both the clevis 26 and sleeve 36. The drive pin 38 has a head 40 at one end, and a flexible “O” ring 44 positioned therebetween to prevent egress and ingress of unwanted fluids out of and into the cavity 16. A piercing pin 46 having one end laterally restricted and coaxially positioned within the central bore 42 of the drive pin 38 and a pointed end coaxially positioned in close proximity to the opening 20 of the main body 10. Near the pointed end of the piercing pin 46 is a piston 50, which is secured thereto by welding or brazing, or preferably it is threadably secured for maintenance purposes, with a flexible “O” ring 52 mounted thereon to keep the gas emitted by the gas storage member 15 in the portion of cavity 16 which is between the piston 50 and the small opening 20. Between the piston 50 and the end wall 19 is positioned a return spring 53 to ensure that the piston is returned a sufficient distance from the end wall 19 after actuation of the PS device so as to allow gas to egress therefrom through the outlet 55. Thus, gas emitted from the gas cartridge 15 passes through the opening 20, enters the cavity 16 and exhausts out the outlet 55 to the flotation device (not shown) connected thereto.

Positioned concentrically about the sleeve 36, drive pin 38 and piercing pin 46, within the cavity 16, is a hammer or striker 54 having a larger rear portion 56 and a smaller front portion 58, joined by a tapered portion or restraining shoulder 60. Secured at the front end of the hammer 54 is an enlarged head portion 62. The hammer 54 is preferably hollow so that it can move axially within the cavity 16 independent with respect to the drive and piercing pins 38,46. A helical spring 64 is concentrically mounted within the hollow of the hammer 54 with one of its ends abutting the inner shoulder 66 and its other end abutting the clevis 26. By this construction, when the hammer 54 is in the position as shown in FIG. 1, the spring 64 is compressed thereby biasing the hammer 54 toward the right end of the main body 10.

Releasably secured at the opposite end of the main body 10 is a handle 68, which has an opening 70 formed in its enlarged outer end 72 and a longitudinal slot formed in its smaller inner end 74. An externally threaded shank 76 is secured to or integrally formed with the enlarged outer end 72 for storing a subverter cap 78 when not in use. Subverter cap 78 has a resilient ring-like member 79 secured to the peripheral edge of its open end and will be further described hereinbelow with regard to the mode of operation of the PS device. The smaller inner end 74 has a central bore formed therein which is shaped to conform to the outer end of the main body 10. Handle 68 is fitted upon the outer end of the main body 10 so that when it is pulled away from the main body 10, it easily slides off, yet fits snugly in place so as to remain thereon during normal use of the PS device. To ensure proper relative positioning of the handle 68 with respect to the main body 10, an inner peripheral shoulder 80 is formed at a selected distance within the central bore to prevent the handle 68 from sliding too far down the main body 10. The central bore in the handle 68 preferably terminates at the enlarged portion of the handle. The lever 30 is positioned within the slot 74 of the handle 68, while the lanyard 82 is connected at one end to the lever 30 while its other end extends through the opening 70 of the handle 68 and secured therein by the knot 84.

The clevis 26, lever 30, drive pin 38, piercing pin 46, handle 68 and lanyard 82 combine to provide manual override of the automatic pressure sensing capability of the PS device, as will be described hereinbelow in more detail.

Extending from the main body 10 is an externally threaded boss 86 having a central bore 88 formed therein. Positioned within the central bore 88 is a restraint pin 90 having a substantially flat upper end and a conical or tapered lower end 92 with a resilient “O” ring 94 positioned therebetween. The tapered end 92 of the restraint pin 88 extends into the cavity 16 and abuts the restraining shoulder 60 of the hammer 54 and

3,802,012 holds the hammer 54 in the position shown in FIG. 1, to wit, the “cocked” position of the PS device in readiness for actuation thereof or for the gas releasing mode of the PS device.

A pressure sensing head 96 is threadably secured to the threaded boss 86 and tightly abutting the resilient washer 97, and includes a cup shaped body 98, a central bore 100, and internal annular groove or slot, selectively positioned openings 102 which extend to the slot 103, an externally threaded shank 104 and a transparent window 106. Positioned within the central bore 100 is a resilient member 108 which is preferably an “O” ring that abuts and seals the annular slot 103. Circumscribing the lower end of the bore 100 is a fluid soluble member 110, preferably disc shaped, that extends beyond the peripheral edge thereof and abuts the shoulder portion 112 of the body 98. The soluble member 110 is of the type that when dry has sufficient strength to hold the restraint pin 90 in its hammer restraining position (as shown in FIG. 1) in opposition to the force exerted by the compressed spring 64 against the hammer 54. However, when the soluble member 110 gets wet it loses its strength by dissolving or disintegrating and thereby releases the hammer 54.

The top of the restraint pin 90 is preferably painted a bright color, such as red, so that when the soluble member has dissolved or disintegrated, the user of the PS device is readily aware of the expended condition by visual observance of the colored top of the restraint pin 90 as viewed through the transparent window 106.

The resilient member 108 of the pressure sensing head 96 is chosen to have expansion and resilience characteristics which will satisfactorily seal the annular groove 103 when the PS device is subjected to an external fluid pressure above a selected value, and will readily compress and unseat itself at one or more areas along its periphery when the PS device is subjected to an external fluid pressure at or above the selected value. By this arrangement, the central bore 100 of the pressure sensing head 96 is maintained free of fluid until the selected external pressure occurs, such as when the PS device is submerged to a selected depth of water. Thus, fluids and other contaminants are prevented from entering the central bore 100 so as to substantially enhance device reliability and uniquely achieve pressure sensing capability primarily independent of chemical or electrical requirements.

Automatic operation of the PS device is as follows:

1. The elements and members are relatively positioned in mechanical and chemical cooperation as shown in FIG. 1 in readiness for a cycle of operation when the PS device is subjected to a selected external fluid pressure, such as submersion to two feet of water.

2. When the external pressure reaches the selected value, the fluid in the slots 102 unseats the resilient member 108 from the annular groove 103 and fluid enters the central bore 100 of the pressure sensing head 96.

3. The fluid soluble member 110 is saturated with fluid and dissolves or disintegrates, thereby releasing the restraint pin 90 so that it moves out of engagement with the hammer 54 but remains within the central bore 88.

4. The compressed spring 64 drives the hammer 54 toward the piercing pin piston 50, striking the pis ton 50 and driving it and the piercing pin 46 with a force sufficient to penetrate the seal on the gas cartridge 15. The piercing pin preferably moves within the drive pin in a coaxial manner therewith and is not secured thereto. The drive pin being used to drive the piercing pin only during manual operation of the PS device. A detailed description of the manual operation of the PS device is set forth hereinbelow in detail.

5. The return spring 53, which is compressed when the piston 50 moves to the right, biases the piston 50 and hammer 54 to the left a sufficient distance to clear both the opening 20 and outlet 55.

6. Gas from the gas cartridge 15 passes through the opening 20, into the cavity 16, and out the gas outlet 55 to a flotation device (not shown) which is both mechanically and fluidly secured to the PS device via the mounting hole 12 and gas outlet 55, respectively.

7. To reset the PS device, the handle 72 is pulled off the housing 10, the bonnet and pressure sensing head 96 are removed from the housing 10, and the expended gas cartridge 15 removed. All elements are then thoroughly dried. A dry soluble member 110 is positioned over the restraint pin 90 and the pressure sensing head 96 is threaded down on the threaded boss 86, ensuring that the hammer 54 is positioned so that its conical member 60 engages the tapered end 92 of the restraint pin 90. It is also important at this point to ensure that the resilient member 108 is properly seated in sealing engagement with the annular groove 103. The bonnet 22 is then threaded down on the threaded end 21 of the housing 10, thereby compressing the spring 64. Finally, the handle 72 is slid onto the housing 10 with the lever 30 and lanyard 82 in position as shown in FIG. 1.

Manual operation of the PS device is effected by pulling the handle 72 away from the housing 10, which causes the lever 30 to pivot about the cross pin 40 due to the lanyard 82 which is connected therebetween. The end of the lever 30 cams against the head 40 of the drive pin 38 which moves to the right and forces the piercing pin 46 to penetrate the seal on the gas cartridge 15, thus actuating the PS device. The return spring 53 ensures that the piston 50 is adequately returned to a position to clear the opening 20 and outlet 55. Note, however, that when the PS device is manually operated, the hammer 54 does not move from the position shown in FIG. 1 by virtue of the fact that the novel concentric sleeve configuration hereinabove described. Thus, by replacing the spent gas cartridge 15 after manual operation, the PS device is in readiness for both subsequent manual and automatic operation without removal of the pressure sensing head 96 and without damage to the soluble member 110, provided of course the subverter cap 78 has been used, i.e., removed from the handle 72 and positioned upon the sensing head 96, as shown in FIG. 10.

The subverter cap 78 is provided for the purpose of preventing automatic actuation of the PS device for any reason, such as, by skin divers who may desire to have automatic actuation after a dive when near the surface, or by military personnel who may wish to subvert automatic operation during certain water phases of a mission. In any event, if it is desireable to subvert automatic operation, the subverter cap 78 is threadably

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Without further elaboration, the foregoing is considered to explain the character of the present invention so others may by applying current knowledge, readily adapt the same for use under varying conditions of service, while still retaining certain features which may properly be said to constitute the essential items of novelty involved, which items are intended to be defined and secured by the appended claims.