Abstract:
A multi-celled ram-air parachute possessing one or more internal one-way valved air passages between at least two parachute cells to maintain positive air pressure within the parachute for the purpose of maintaining shape and rigidity when less than optimal airspeed is present thereby increasing a user&#39;s control and safety.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to parachutes and paragliders. More particularly, it relates to ram-air type parachutes and paragliders that include a plurality of cells with at least one valve in at least one of the cells to inhibit deformation of the air wing structure. 
     Much like an airplane wing, a ram-air parachute possesses an airfoil that provides lift and allows the operator to control the direction, speed and rate of descent. The shape and rigidity of a parachute determine such flight characteristics. Generally, a ram-air parachute consists of an upper surface and a lower surface connected by a plurality of vertically attached ribs. A cell of the parachute is the part of the parachute between the upper and lower skins bordered by a rib on one side and an adjacent rib on the other. Much like an airplane wing, one of the purposes of these ribs is to help the wing to keep its shape and strength. Load bearing ribs support and distribute the weight of the user by bearing forces of the lines connecting the user to the parachute. 
     Generally a parachute has lightning holes cut into the ribs to reduce its packed bulk and keep it evenly pressurized when inflated. The holes in the ribs of a parachute are called crossports and allow the air to communicate or move from higher pressurized cells to lower pressurized cells. The parachute is pressurized by high pressure air entering inlets along the leading edge of the parachute. Some parachutes possess internal cross braces, usually in the form of diagonal pieces of fabric connecting the top of one rib to the bottom of an adjacent rib. These cross braces provide additional support to the canopy and maximize the surface area of the parachute. 
     What keeps a traditional ram-air parachute pressurized, therefore, is the constant flow of air into or against the air inlets of the parachute. On a normal ram-air parachute more airflow means more rigidity and less airflow means less rigidity, less airflow also means the parachute will shrink in size. The reason the ram-air parachute looses rigidity and size with less airflow is due to air spilling out of the leading edge. Loss of parachute rigidity occurs when the parachute is slowed for landing and can also occur when flying in turbulent air. 
     Operators generally will select a parachute that matches their skill level and desired performance characteristics. Performance generally increases as the parachute size is reduced, allowing the operator to fly a faster, more responsive parachute. When the parachute is slowed for landing, however, the parachute looses rigidity and shrinks further in size, reducing lift and increasing the stall speed of the parachute. In order to land safely, an operator must select a parachute having a sufficiently large surface area to ensure a safe landing speed, while possessing a small enough surface area so that the parachute possesses the desired performance characteristics. 
     Reduced stall speed during slow landings due to loss of rigidity and shrinkage is one problem associated with ram air inflated parachutes. Loss of rigidity may ultimately lead, however, to the parachute canopy collapsing which can lead to injury or death of the user. Should the canopy be allowed to lose sufficient rigidity, the parachute may collapse and greatly increase the vertical descent of the operator. Landing is a particular vulnerable time for the parachute user, where slow speed, ground induced turbulence and reduced recovery time increase the risk of canopy collapse. 
     In order to increase maneuverability, reduce the stall speed and increase safety, it is desirable for a parachute to maintain a positive pressure within the majority of cells. It is especially important when encountering slow speed conditions or turbulence. It is also desirable for the parachute to maintain rigidity and maximum lift capacity during slow speed maneuvers such as landing allowing the operator to select and safely fly smaller parachutes for increased performance. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention disclosed herein maintains the rigidity and shape of a ram-air parachute when air pressure against the air inlets of the parachute provides inadequate pressurization. Generally this is accomplished by closing off the air inlets on one or more cells and turning one or more of the crossports into one-way valves. Valving can be accomplished by partially sewing a panel of material, such as zero-porosity or low-porosity parachute material, over the crossport. When pressure is lower on the side of the crossport where the valve panel is attached, air is allowed to flow through the crossport to pressurize that cell and any other cells in communication with that cell. However when air pressure is higher in the cell on the side of the crossport where the valve panel is attached than the other side of the crossport, the airflow is reversed and the valve panel is urged against the rib material surrounding the crossport creating a seal preventing depressurization of the parachute. 
     Partial attachment of the valve panel to the rib material prevents the valve from being forced through the crossport. In another embodiment the valved crossports possess a breathable mesh material attached over the opening of the crossports. In such embodiment the mesh material prevents the valve material from passing through the crossport. By positioning the valved crossports within the ribs of the parachute, an airlock designed parachute can be achieved that also possess the additional stabilizing effects of cross bracing. 
     The resulting parachute provides reduced stall speeds at slow speeds. Slower stall speeds allow the user to select a smaller parachute for increased performance characteristics while providing a larger canopy area at landing than what could be achieved with a parachute otherwise lacking one-way valves. The resulting parachute also increases stability in turbulent or low speed conditions, increasing the user&#39;s safety and generally providing for a more enjoyable experience. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is illustrated by the accompanying drawings, in which: 
         FIG. 1  is a front perspective view of the invention showing outboard positioned air inlets. 
         FIG. 2  is a front perspective view of the invention showing air inlets positioned in the center cell of the parachute. 
         FIG. 3  is a front perspective cutaway view of the parachute flying in turbulent conditions with the crossport valves responding by closing to prevent loss of parachute rigidity or canopy collapse. 
         FIG. 4  is a front perspective cutaway view of the crossport valves in the open position. 
         FIG. 5  is an exploded perspective view of the valve mechanism. 
         FIG. 6  is an exploded perspective view of the valve mechanism with mesh material. 
         FIG. 7A  is a side view of a rib and valve mechanism showing one embodiment of valve panel attachment. 
         FIG. 7B  is a side view of a rib and valve mechanism showing another embodiment of valve panel attachment. 
         FIG. 7C  is a side view of a rib and valve mechanism showing another embodiment of valve panel attachment. 
         FIG. 7D  is a side view of a rib and valve mechanism showing another embodiment of valve panel attachment. 
         FIG. 8  is a front perspective cutaway view of the invention showing the internal rib bracing, crossports and outboards positioned crossport valves. 
         FIG. 9  is a front perspective cutaway view of the invention showing the internal rib bracing, crossports and crossport valves positioned between each parachute cell. 
         FIG. 10  is a front view of the leading edge of the parachute showing the air inlets and internal cross bracing. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The drawings illustrate an invention that enables a parachute to retain its rigidity and shape when flying in turbulent air or at low speeds. 
       FIG. 1  shows one embodiment of the present invention  1  employed as a parachute and deployed and inflated in flight. The parachute  1  is comprised of a an upper skin  12  of a generally rectangular shape and a lower skin  14  of substantially the same configuration each having a leading edge  3  a trailing edge  5  and a pair of generally opposing lateral edges  7 . The lower skin  14  is disposed beneath and joined to the upper skin  12  at the trailing edge  5 , the leading edge  3  and by a plurality of elongated rib members  16 . The joining of the rib members  16  in the present embodiment can be seen in  FIG. 1  as parallel seam lines  18 . Load bearing ribs  20  bear and distribute the weight of the payload such as an operator  2 , suspended beneath the parachute  1 . Generally, suspension lines  26  connect to, or proximately to a load bearing rib  20  that in turn distribute the tensile forces to the upper skin  12  and lower skin  14 . Suspension lines  26  may also be connected to stabilizers  24 . In this embodiment a plurality of air inlets  30  are positioned on the outboard leading edge  3  portion of the parachute  1 . The remaining portions of the leading edge  3  of the parachute  1  are closed to allow air entering the air inlets  30  to inflate the volume between the upper and lower skins  12 ,  14 . During deployment of the parachute  1 , air enters the air inlet  30  and flows toward the center of the parachute  1  inflating it. After inflation, airflow within the parachute  1  slows, and pressure from air flowing against the air inlet  30  maintains the parachute&#39;s inflated state. 
       FIG. 2  illustrates an alternative embodiment of the current invention where the air inlets  30  are positioned in the center or inboard section of the parachute  1 . In this embodiment, air flows in through the center air inlets  30  toward the outboard portions of the parachute  1 . 
       FIG. 3  shows a perspective partial cutaway view of the parachute  1  showing the one way valves  110 ,  120  positioned upon an internal rib  16 . The rib  16  is attached at its upper edge  13  to the upper skin  12  and attached at its lower edge  15  to the lower skin  14 . Air flow, represented by arrows, is shown entering the air inlets  30  on the leading edge of two outboard cells  34 . The air pressure urges the valves  110 ,  120  into an open position, allowing the air to flow to the adjacent inboard cells  32 . The valves  110 ,  120  in this embodiment are comprised of panels  112  and  122  of low porosity or zero porosity fabric. The upper edges  114 ,  124  and lower edges  116 ,  126  are joined to the rib  16  by any appropriate means, including sewing, bonding, or gluing. 
       FIG. 4  shows a perspective partial cutaway view of the parachute  1  under slow speed or turbulent wind conditions. Inadequate air flow against the air inlets  30  results in lower air pressure in the outboard cells  34 . When air pressure is lower in the outboard cells  34  containing the air inlets  30  than the air pressure in the inboard cells  32 , the air pressure urges the panels  112 ,  122  against the rib  16 , closing the valves  110 ,  120  and slowing or stopping the loss of air from the inboard parachute cells  34  to the outboard cells  34 . Airflow through the crossports  36  is stopped and parachute rigidity and shape is generally maintained. 
       FIG. 5  shows an exploded perspective view of the preferred embodiment of the valve  120 . In this embodiment a flexible valve panel  122  is attached, generally at its edges, to the rib  16  of the parachute. The valve panel  122  is preferably constructed from zero porosity parachute fabric. Zero porosity fabric is generally a tightly woven synthetic, such as rip stop nylon possessing a coating that seals the small gaps between the individual fibers of the fabric. While zero porosity fabric is preferred, other type of material, including low porosity fabric may also be used. 
       FIG. 6  shows an exploded perspective view of another embodiment of the valve  120 ′. In this embodiment, an air permeable mesh material  38  is attached to the rib  16  over each of the crossports  36  of the valve  120 ′. A flexible valve panel  122  is attached to the rib material. The mesh  38  prevents the valve panel  122  from being pushed through the crossports  36  when the air exerts pressure on the valve  120 ′ and the valve panel  122  seals the crossports  36 . The additional mesh material  38  allows a greater amount of the valve panel  122  to be free from attachment to the rib  16  allowing greater airflow through the crossport  36  when the valve  122 ′ is open. 
       FIG. 7A  shows the preferred attachment of the valve panel  110 . Here the valve panel  110  is affixed at its upper edge  114  and lower edge  116  to the rib  16  of the parachute  1  over a single crossport  36 . The left edge  115  and right edge  117  of the panel remains unattached to allow airflow between the rib  16  and the valve panel  110  when air urges the valve panel  110  in the open position. When airflow is reversed, the air pressure presses the valve panel  110  against the rib  16  in a sealing relationship closing the valve  112  and maintaining the rigidity and shape of the parachute. In the preferred embodiment the panel  110  is attached by a row of stitching  128 . Other attachment methods may be used, including bonding or gluing the valve panel  110  to the rib  16 . 
       FIG. 7B  shows another embodiment of the preferred attachment of the valve panel  120 . Here multiple crossports  36  are covered by a single valve panel  120 . The attachment of the valve panel at its top edge  124  and bottom edge  126  allows air to flow through the crossport  36  and past the left edge  125  and right edge  127  to inflate the parachute. 
       FIG. 7C  shows yet another embodiment of invention where the valve panel  110  is attached to the rib  16  at the valve panel&#39;s left edge  115  and right edge  117  by a row of stitching  128  over a single crossport  36 . Here, air will flow through the crossport  36  and past the upper edge  114  and lower edge  116  of the valve panel  110  when the valve  110  is in the open position. As with the previous embodiments, when airflow is reversed, the valve  112  will close preventing the air to flow past the crossport  36  and out of the parachute  1 . 
       FIG. 7D  shows yet another embodiment of the invention where the valve panel  120  is attached to the rib  16  over multiple crossports  36 . In this embodiment the upper edge  124  and lower edge  126  of the valve panel  120  remain unattached. A vertical row of stitching  128  at the left edge  125  and a vertical row of stitching  128  at the right edge  127  secure the valve panel  120  to the rib  16 . In this embodiment an optional additional vertical row of stitching  128 ′ between the crossports  36  provides additional attachment support of the valve panel  120  to the rib  16 . 
       FIG. 8  shows a perspective cutaway view of the preferred embodiment of the parachute  1  showing the elongated ribs  16  crossports  36  and valve panels  110  and  130 . In the preferred embodiment shown here, the valves  112  and  132  are positioned on a rib  16  inboard from the outboard positioned air inlets  30 . Air enters an air inlet  30  flowing through the crossports urging the valve panel  110  and  130  open. The air flows though the valve  112  and  132  and into the inboard cells  32  of the parachute  1  where it inflates and pressurizes the interior of the parachute  1 , giving the parachute  1  its shape and size. The valves  112  and  132  prevent air from escaping from the inboard cells  32  to the outboard cells  34  and out of the parachute  1  through the air inlets  30 . When the air pressure is less in the outboard cells  34  than in the inboard cells  32 , the valves  112  and  132  seal the crossports  36  on the outboard positioned ribs  16  preventing depressurization of the parachute. While in the preferred embodiment the valves  112  and  132  are positioned on load bearing ribs  20 , the valves  112  and  132  may be positioned on non load bearing ribs. While this embodiment depicts two valves positioned on the same rib, one valve panel  130  covering three crossports  36  and another valve panel  110  covering a single crossport  36 , it should be understood than any desired number of valves may be positioned upon an individual rib  16 , each valve panel covering any desired number of cross ports  36 . 
       FIG. 9  shows a perspective cutaway view of another embodiment of the parachute  1  showing the elongated ribs  16  crossports  36  and valve panels  120 . In this embodiment each of the load bearing ribs  20  possess valves  122  covering the crossports  36 . Each of the valves allow air to travel from the outboard cells  34  of the parachute to the center cells  33  of the parachute. The valves  122  prevent air from escaping through the crossports  36  when air pressure in the outboard cells  34  is less than the inboard cells  32 . Having valves positioned on multiple ribs provides additional redundant safety to ensure proper inflation of the parachute during flight. 
       FIG. 10  shows a partial front view of the leading edge  3  of the outboard section parachute  1 . Cross braces  17  are attached diagonally from the bottom of one rib to the top of an adjacent rib. These cross braces  17  provide additional support for the parachute  1  when in flight and under load by supporting the portion of the parachute  1  between the load bearing ribs  20 . Positioning of the valve  122  on the internal ribs  16  of the parachute allows for use of valves  122  to maintain the parachute  1  shape during turbulent or slow speed conditions and allows for use of cross braces  17 . The cross braces  17  are constructed from any suitable lightweight fabric. The cross braces  17  are constructed in a manner that allows airflow through each cell to each adjacent cell. Such cross braces may be constructed so as to not extend the full length of the rib, possess openings, and/or are constructed of a porous material.