Abstract:
The present invention is directed to an airbag system that a user can deploy to reduce the chances of being buried in an avalanche or if buried, likely being buried near the surface, thereby improving the user&#39;s chances of surviving the experience. In one embodiment, the airbag system is comprised of an inflatable balloon, a pressure gas cylinder for holding a pressurized gas that is used in inflating the balloon, a valve that can be placed in a closed state to retain a pressurized gas in the pressure gas cylinder or an open state in which pressurized gas is released from the pressure gas cylinder. The system further comprises an ejector that operates to use pressurized gas received from the pressure gas cylinder and ambient air to inflate the balloon. Also part of the system is a flow restrictor that is located to receive pressurized gas from the pressure gas cylinder before the ejector receives the gas. A harness supports the noted elements of the system adjacent to an individual&#39;s body.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an airbag system that a user can deploy in an avalanche situation to increase the user&#39;s chances, if caught in the avalanche, of surviving the avalanche. 
     BACKGROUND OF THE INVENTION 
     Generally, avalanches are composed of snow structures that range in volume from the volume associated with an individual snow flake to a block of consolidated snow or ice that has a volume of several cubic meters. It has been found that the snow structures with larger volumes tend to stay on or migrate towards the surface of the avalanche, while snow structures with lower volumes stay on or migrate towards the bottom of the avalanche, i.e. migrate to a location nearer to the ground and further from the surface. 
     One way for an individual to increase their chances of surviving an avalanche is to inflate an airbag in an airbag system that is attached to the individual to increase the volume associated with the individual. Once the airbag is inflated, the volume associated with the individual is the volume of the individual plus the volume of the inflated airbag. The greater volume associated with the individual is likely to keep the individual at the surface of the avalanche or, if buried by the avalanche, near the surface of the avalanche, thereby increasing the individual&#39;s chances of surviving the avalanche. 
     Generally, airbag systems for use in avalanche situations employ at least one airbag or balloon, a pressure gas cylinder for holding the pressurized gas that is used to inflate the airbag, and a valve that can be opened to release the pressurized gas to inflate the balloon in an avalanche situation. Many airbag systems also employ an element known as an ejector to reduce the amount of pressurized gas that the user of the system must carry. The ejector receives the pressurized gas from the pressure gas cylinder when the valve is opened and uses the pressurized gas to draw in ambient air to create a gas stream for inflating the airbag that is a combination of gas from the pressure gas cylinder and the drawn-in, ambient air. At least one airbag system utilizes a two-stage ejector that inflates that airbag with gas from the pressure gas cylinder and two separate streams of ambient air. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an airbag system for use in avalanche situations that employs an ejector. However, relative to many known airbag systems that employ an ejector, the airbag system of the present invention is capable of inflating an airbag using less pressurized gas. More specifically, if these known systems and the airbag system of the present invention are each designed to fill an airbag of a specified volume, the airbag system of the present invention will require less pressurized gas than these known systems. As a consequence, the airbag system of the present invention can employ a smaller pressure gas cylinder that occupies less volume and, depending upon the design of and the material employed in the pressure gas cylinder and, is likely lighter than the pressure gas cylinders of these known systems. 
     In one embodiment, an airbag system is provided that is comprised of an inflatable balloon, a pressure gas cylinder for holding a pressurized gas for use in inflating the balloon, and a valve situated between the balloon and the pressure gas cylinder that can be placed in a closed state to retain the pressurized gas in the pressure gas cylinder and in an open state to release the pressurized gas from the pressure gas cylinder for use in inflating the balloon. The airbag system also employs an ejector that utilizes the gas released from the pressure gas cylinder to produce a gas stream for inflating the balloon that is a combination of the gas from the pressure gas cylinder and ambient air. The system also employs a flow restrictor that is located to receive, when the valve is in the open state, gas from the gas pressure cylinder before the gas is received by the ejector. When the valve is in the open state, gas is flowing from the pressure gas cylinder towards the balloon. The flow restrictor serves to drop the inlet gas pressure at the ejector such that the ejector operates more efficiently, i.e., is able to draw in a greater volume of ambient air into the combined gas stream provided to the balloon. In one embodiment, the airbag system was able to use approximately 40% less gas, i.e. the gas from the cylinder, than a known airbag system with a balloon of substantially equal inflated volume to the balloon employed in the present invention. 
     In another embodiment, the flow restrictor is located to receive, when the valve is in an open state, gas from the pressure gas cylinder before the gas is received by the valve. To elaborate, the valve is comprised of a movable block, a first port that is on the cylinder-side of the movable block, and a second port that is on the balloon-side of the movable block. The movable block operates to place the valve in: (a) a closed state in which gas from the cylinder is prevented from flowing from the first port to the second port and (b) an open state in which gas from the cylinder is allowed to flow from the first port to the second port. In this embodiment, the flow restrictor is located on the same side of the movable block as the first port. In another embodiment, the flow restrictor is located on the same side of the movable block as the second port, i.e., between the movable block and the ejector. 
     In yet a further embodiment, the airbag system further comprises a filling port that allows gas to be injected into the pressure gas cylinder. The filling port intersects the first port of the valve, i.e., the port that is on the cylinder-side of the movable block. Consequently, when the pressure gas cylinder is being filled, gas travels through the filling port and then through the first port into the pressure gas cylinder. In this embodiment, the flow restrictor is located between the intersection point and the bulk of the pressurized gas. Stated differently, the flow restrictor is located to receive gas when the valve is in an open state before the gas passes the intersection point of the filling port and the cylinder side port. By placing the flow restrictor at this location, the heating of the pressure gas cylinder that occurs during the injection of gas into the pressure gas cylinder during a typical filling operation is reduced. 
     Yet a further embodiment of the airbag system employs a flow restrictor and a single-stage ejector. As such, the ejector design is substantially less complicated than in airbag systems that employ a multi-stage ejector. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A and 1B  respectively, are rear and front perspective views of a backpack embodiment of the airbag system of the present invention; 
         FIG. 2  illustrates the airbag related components of the backpack embodiment of the airbag system shown in  FIGS. 1A and 1B ; 
         FIG. 3  illustrates the airbag of the backpack embodiment of the airbag system shown in  FIGS. 1A and 1B  in an inflated condition. 
         FIGS. 4A ,  4 B, and  4 C respectively are top, side and end view of a valve and flow restrictor assembly; 
         FIG. 5  is a cross-sectional view of the valve and flow restrictor assembly; 
         FIG. 6  is a exploded, cut-away view of the valve and flow restrictor assembly; 
         FIG. 7  illustrates a shoulder strap of the backpack embodiment of the airbag system shown in  FIGS. 1A and 1B  with a handle that is used to place the valve in open state to deploy the balloon and a pocket to prevent the handle from being pulled at an undesirable time; and 
         FIGS. 8A ,  8 B, and  8 C respectively are top, side and cross-sectional views of a single-stage ejector used in the embodiment of the airbag system shown in  FIGS. 1A and 1B . 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1A ,  1 B, and  2  illustrate an embodiment of an airbag system for use in avalanche situation. The embodiment of the airbag system is hereinafter referred to as system  20 . The system  20  is comprised of an inflatable balloon  22 , a pocket  24  that holds the balloon  22  when deflated and opens when the balloon is being inflated, a pressure gas cylinder  28  for holding pressurized gas that is used to inflate the balloon  22 , a valve and flow restrictor assembly  30 , high-pressure tubing  32 , a single-stage ejector  34  that receives gas provided by the cylinder  28  via the high-pressure tubing  32  and provides a combined stream of gas from the cylinder  28  and ambient air to the balloon  22 , an air box  36 , and air intake cover  38 , a harness  40 , and a sack  42  for holding a user&#39;s gear. 
     The harness  40  is used to support the other elements of the system  10  and to attach the other elements of the system  10  to a user. The harness  40  is comprised of a molded ethylene vinyl acetate (EVA) panel  44  that is commonly used in back packs, a pair of shoulder straps  46 A,  46 B that each engage the panel  44 , and a buckled waist belt  48  that also engages the panel  44 . It should be appreciated that the invention is capable of being used with any type of harness that is capable of: (a) supporting the other elements of the invention that are needed to store and deploy a balloon in an avalanche situation and (b) attaching these other elements adjacent to a user&#39;s body. Examples of other harnesses include climbing harnesses and packs that have metal ladder-frames, shoulder straps, and waist belts. Other examples of harnesses include items of clothing, such as jackets, vest, coats, parkas and the like. It should be appreciated that the other types of harnesses also suggest that the sack  42  is part of the backpack embodiment of the system but is not a necessary element of the system. 
     The inflatable balloon  22  is made of a tear resistant and substantially gas impermeable material, such as a coated nylon. Other materials are also feasible. With reference to  FIG. 3 , the balloon  22  is structured so that, when deployed by an individual that is properly wearing the harness, the inflated balloon occupies a space that is substantially behind a plane that is generally defined by the user&#39;s back and the panel  44 . As such, the inflated balloon does not interfere with the user&#39;s ability to look forward and to each side. Further, the inflated balloon does not occupy the space defined by the normal range of motion of the user&#39;s legs. Consequently, the inflated balloon does not interfere with the user&#39;s ability to move their legs in attempting to evade or cope with an avalanche situation. The inflated balloon also does not occupy all or a substantial portion of the space in which a user is normally able to move their arms that is forward of the noted plane defined by the user&#39;s back and the panel  44 . It should be appreciated that the invention is not limited to a particular balloon shape or deployment in a particular space relative to a user. The balloon shape and the space in which the balloon is deployed when in use can be adapted to different embodiments of the invention. The balloon is also structured so that when it is fully inflated, it occupies a space of about 150 liters. 
     The pocket  24  is defined by a front and rear portions  50 A,  50 B, a rear seam  52  that joins the front and rear portions  50 A,  50 B to one another, and an opening  54  that employs a fastener that is capable of closing the pocket  24  to store the balloon  22  but can be opened upon deployment of the balloon  22 . In one embodiment, the fastener is a hook-and-loop type of fastener, such as a Velcro fastener. When a hook-and-loop fastener is employed, the Velcro fastener does not extend over a small portion of the opening  54  to facilitate the separation of the hook and loop elements of the fastener from one another when the balloon begins to inflate. The rear seam  52  also engages the rear end of the balloon  22 . The rear seam  52  also includes a number of loops  56  through which a cord passes and is used to anchor the balloon  22  and pocket  24  to the panel  44 . The fastening of the balloon  22  and pocket  24  to the panel  44  in this manner allows the balloon  22  and pocket  24  to be readily detached should the balloon  22  become damaged and require replacement or the balloon  22  otherwise needs to be removed, such as in a rescue situation. The pocket  24  is generally U-shaped to accommodate the shape of the balloon  22 . Further, the pocket  24  is sized so that the balloon  24  fits tightly within the pocket  24 , which also aids in the ability of the balloon  24  to deploy from the pocket  24  during the inflation operation. 
     With reference to  FIG. 2 , the pressure gas cylinder  28  is a stock pressure gas cylinder that is rated to at least 3000 psi and, at 3000 psi, contains approximately 42 standard liters of compressed gas. In the illustrated embodiment, the cylinder  28  preferably has a volume of less than 20 cubic inches of water, more preferably less than about 15 cubic inches of water. Typically, the cylinder  28  is filled with air. However, other gases, such as nitrogen, can also be used. Sites that are capable of filling the cylinder  28  up to at least the 3000 psi pressure rating include SCUBA shops, fire stations, and paintball facilities. The cylinder  28  includes a threaded opening for engaging the valve and flow restrictor assembly  30 . 
     With reference to  FIGS. 4A-4C ,  5 , and  6 , the valve and flow restrictor assembly  30  is described in greater detail. The assembly  30  is comprised of a housing  60  with a threaded collar  62  for engaging the threaded opening of the cylinder  28 . In connection with the valve, the housing  60  defines a path for pressurized gas to flow from the cylinder  28  and towards the balloon  22 . The path includes a first port  64  that is in fluid communication with the interior of the cylinder  28  (the cylinder-side port) and a second port  66  that is in fluid communication with the balloon  22  via the ejector  34  and the high-pressure tubing  32  (the balloon-side port). Interposed between the first and second ports  64 ,  66  is a movable block element  68  that is capable of being positioned to place the valve in: (a) a closed state in which pressurized gas contained within the cylinder  28  is prevented from flowing from the first port to the second port and (b) an open state in which pressurized gas contained with the cylinder  28  is allowed to flow from the first port to the second port and on towards the balloon  22 . In the illustrated embodiment, the movable block element  68  is comprised of a valve stem  68 , a portion of which is capable of being moved into and out of the space within the housing  60  at which the first and second ports  64 ,  66  intersect one another to respectively place the valve in the closed and open states. The valve stem  68  is supported within a space  70  within the housing  60  by a threaded hex plug  72  that is engaged the housing  60 , spacer tube  74 , a pair of radial seal elements  76 A,  76 B to prevent the flow of gas past the valve stem  68  through the space  70 , a pair of back-up rings  78 A,  78 B to prevent undue movement of the radial seal elements  76 A,  76 B through the space  70 , and an annular flow spacer  80 . The hex plug  72  and spacer tube  74  also serve to hold the radial seal elements  76 A,  76 B, back-up rings  78 A,  78 B, and annular flow spacer  80  in place within the space  70 . With reference to  FIG. 5 , the valve stem  68  is positioned so as to place the valve in the closed state, i.e., communication of gas from the first port  64  to the second port  66  is prevented. The valve stem  68  is capable of, with reference to  FIG. 5 , being moved to the left to place the valve in the open condition to allow gas to flow from the first port  64  to the second port  66 . A shoulder  82  of the valve stem  68  and the hex plug  72  cooperate to limit the leftward movement of the valve stem  68  and prevent the valve stem  68  from being totally removed from the space  70 . It should be appreciated that in this embodiment the valve is a pressure balanced valve, i.e., a valve in which no active element (such as a spring) is required to counteract the pressure within the cylinder  28  to hold the valve in a closed state. This, in turn, allows the state of the valve to be changed from the closed state to the open state with a direct actuation device, i.e., an actuation device that does not need to overcome the operation of an active element in holding the valve in a closed state. It should also be appreciated that other valves can be used to control the flow of gas from the cylinder  28  to the airbag  22 . 
     With reference to  FIGS. 4B and 7 , displacement of the valve stem  68  from the position in which the valve is in the closed state ( FIG. 5 ) to the position in which the valve is in the open state, is accomplished using a metal cord  86 , one end of which is attached to the valve stem  68  and the other end of which is attached to a handle  88  located adjacent to shoulder strap  46 A. The metal cord is housed within a sheath  90  to prevent the cord from abrading the materials of the shoulder strap  46 A and other material associated with system  20  that is located between the handle  88  and the valve and flow restrictor assembly  30 . To prevent the handle  88  from being inadvertently pulled and the valve placed in the open condition, a sealable pocket  92  for housing the handle  88  is associated with the shoulder strap  46 A. With reference to  FIG. 6 , another feature that prevents the valve from being placed in the open state are the hole  94  in the valve stem and the hole  96  in the hex plug  72 , which can be aligned and accommodate a cotter pin or similar device. 
     The housing  60  also defines a pressure sensing port  100  that communicates with the first port  64  and accommodates a threaded pressure indicator/gauge  102  that allows a user to determine if the cylinder  28  contains sufficient gas for inflating the balloon  22  before engaging in an activity in which the user might be exposed to an avalanche situation. 
     The housing  60  also defines a filling port  104  that communicates with the first port  64  at an intersection point  65  and accommodates a threaded, quick-connect one way valve  106 . The valve  106  allows the air charging systems employed in fire stations, SCUBA/dive shops, paintball shops and the like to be used to inject air into the cylinder  28 . As should be appreciated, the valve must be in the closed state in order for a charging system to inject air into the cylinder  28  up to the needed or desired pressure. 
     Also defined by the housing  60  is a burst port  108  that accommodates a threaded, burst plug  110  that is designed to vent the gas contained in the cylinder  28  if the pressure in the cylinder  28  exceeds a certain level, thereby reducing the possibility of the cylinder  28  exploding. In the illustrated embodiment, the burst plug  110  is designed to vent gas from the cylinder when the pressure within the cylinder  28  exceeds 4500 psi. 
     The housing  60  also contains a flow restrictor  114  that, when the valve is in the open state, reduces the pressure presented at the input to the ejector such that the ejector can draw in significantly more ambient air than if a flow restrictor is not employed. This, in turn, reduces the amount of gas that is needed from the cylinder  28 . Consequently, a smaller cylinder  28  can be employed and, other things being equal, reduces the weight of the system  20 . Further, the flow restrictor  114  produces a reasonably fixed pressure ratio as the flow of gas crosses it. As such, the pressure on the downstream side falls in time in proportion to the pressure in the cylinder  28 . The flow restrictor  114  is a threaded plug that engages the first port and defines an orifice  116  having a diameter in the range of 0.010 to 0.060 inches and more preferably in a range of 0.020 to 0.040 inches. In the illustrated embodiment, the orifice of the flow regulator has a diameter of 0.030 inches. Using the flow restrictor  114  allowed a cylinder  28  that held approximately 41 standard liters of pressurized air at 3000 psi to operate in conjunction with the single-stage ejector  34  to fill a balloon with a fully inflated volume of 150 liters. The flow restrictor  114  is located in the first port  64  and between the filling port  104  and the end of the first port  64  that is furthest from the valve stem  68 . As such, the flow restrictor  114  functions as previously noted when the valve is in the open state and gas is flowing from the cylinder  28  through the first and second ports  64 ,  66  and on towards the balloon  22 . In addition, when the valve is in the closed state and gas is being injected into the cylinder  28  via the filling port  104 , the flow restrictor  114  serves the additional function of keeping the cylinder  28  cooler than if the flow restrictor  114  was not present. It should be appreciated that a flow restrictor need not be located within a housing that also houses a valve, i.e., the flow restrictor can be embodied in a separate part that is operatively connected to the valve. Further, a flow restrictor can be located between the valve and the ejector. However, a flow restrictor so located does not provide the cooling benefit during filling of a flow restrictor that is located as illustrated in  FIG. 5 . 
     With reference to  FIGS. 8A-8C , the single-stage ejector  34  is comprised of a housing  120  that defines an outlet space  122  for conveying a gas stream that is a combination of gas from the cylinder  28  and ambient air to the balloon  22 . The housing  120  also defines an inlet space  124  that receives gas from the cylinder  28  when the valve is in the open state and ambient air. The gas from the cylinder  28  is received into the inlet space  124  via an inlet port  126  that receives gas from the cylinder  28  via the valve and the high-pressure tubing  32 . Ambient air is received into the inlet space  124  via a spring loaded port  128  that is open when the ejector  34  is receiving sufficient gas from the cylinder  28  to create a vacuum sufficient to overcome the force of a spring and closed when the ejector  34  is not receiving sufficient gas from the cylinder  28  to create a vacuum sufficient to overcome the force of the spring. The spring loaded port  128  is comprised of a circular port  130  that fits within a hole  132  defined by the housing  120 , a generally T-shaped port mount  134  that engages the port  130  and spans a diameter greater than the diameter of the hole  132 , a stand  136  that engages the mount  134 , and a spring  138  housed within the stand  136 . 
     In operation, the ejector  34  receives gas from the cylinder  28  via the inlet port  126 . The received gas from the cylinder passes into the outlet space  122  via an orifice  140 . In the illustrated embodiment, the orifice has a diameter of about 0.042 inches. Provided there is sufficient gas from the cylinder  28  being injected into the outlet space  122 , a vacuum will be established on the interior side of the circular port  130 . This will cause the port  130  to be displaced towards the spring  138  and will allow ambient air to pass through the hole  132  and into the outlet space  122 , thereby creating a stream of gas for filling the balloon that is a combination of gas from the cylinder  28  and ambient air. Once there is insufficient gas from the cylinder passing into the outlet space to create a sufficient vacuum for overcoming the force of the spring  138 , the circular port and T-shaped mount  134  will seal the hole  132 , holding pressure in the balloon  22  by acting as a non-return valve. 
     With reference to  FIG. 2 , the air box  36  serves to establish a path for ambient air to be received by the ejector  34 . As such, the air box  36  is connected to the portion of the housing  120  of the ejector  34  that includes the hole  132 . The periphery of the air box  36  is connected to the rear side of the panel  44  and over a hole in the panel  44 . With reference to  FIG. 1B , the air intake cover  38  is connected to the front side of the panel  44  and over the hole in the panel  44 . With reference to  FIGS. 1A ,  1 B, and  2 , it should be appreciated that the balloon  22 , pocket  24 , cylinder  28 , high-pressure tubing  32 , ejector  34 , and air box  36  are all located on the rear side of the panel  44  and, as such, are protected by the panel  44  and the sack  42 . Further, in the illustrated embodiment, the noted elements located on the rear side of the pack are accessible via the sack  42 . 
     Operation of the system  20  involves placing the system  20  in a operable condition and, once the system  20  is in an operable condition, using the system  20  to deploy the balloon  22 . Generally, placing the system  20  in an operable condition comprises: (a) placing the balloon  22  in the pocket  24  and engaging the fastener associated with the pocket  24 , and (b) charging the cylinder  28  with gas to a sufficient pressure so that when the valve is placed in the open condition, the balloon  22  will deploy from the pocket  24 . Preferably, placing the balloon  22  in the pocket  24  involves folding the balloon  22  in an accordion type fashion, positioning the folded balloon  22  in the pocket  24 , and engaging the fastener associated with the pocket. To charge the cylinder  28 , the valve is placed in the closed position, i.e., the valve stem  68  is position as shown in  FIG. 5 . Further, to prevent displacement of the valve stem  68  during the filling process, the hole  94  of the valve stem  68  is aligned with the hole  96  associated with the hex plug  72  and a cotter pin or similar device is placed in the aligned holes, thereby preventing the valve stem  68  from being inadvertently displaced and the valve placed in the open state. The cylinder  28  is then charged with gas by connecting the quick-connect one way valve  106  to a suitable charging device. Once the cylinder  28  is sufficient charged with gas, the charging device is disconnected from the valve  106 . After the cylinder  28  is charged and when a user is in a possible avalanche situation, the cotter pin or similar device is removed so that the valve can be placed in the open state, if needed, and the handle  88  is removed, if needed, from the pocket  92 . At this point, a user can cause the balloon  22  to be deployed from the pocket  24  by pulling on the handle  88  to place the valve in the open state. With the valve in the open state, gas from the cylinder  22  passes through the valve and flow restrictor assembly  30  and into the ejector  34 . The ejector  34  operates to produce a gas stream that is a combination of the gas from the cylinder  28  and ambient air. The ejector  34  provides this combination gas stream to the balloon  22 . The balloon  34 , in turn, begins to inflate and eventually causes the fastener associated with the pocket  24  to release. At this point, the balloon  22  deploys from the pocket  24 . 
     While the invention has been particularly shown and described with reference to various embodiments thereof, it will be readily understood by those skilled in the art that various changes in the form and detail may be made without departing from the spirit and scope of the invention.