Abstract:
Evacuation slide systems having extendable portions are detailed. The extendable portions of slides may be inflated separately from the main portions and actuated manually if desired. Consequently, attitude changes of, for example, an aircraft subsequent to inflation of the main portion of a slide would not necessarily defeat its use, as inflation of the extendable portion could still occur.

Description:
FIELD OF THE INVENTION 
     This invention relates to evacuation equipment and more particularly, although not necessarily, to extendable slides for use in evacuating aircraft. 
     BACKGROUND OF THE INVENTION 
     Inflatable slides for evacuating, in particular, commercial fixed-wing aircraft are well known. Such slides typically are stowed on-board aircraft in uninflated states and mounted on, in, or near exit doors. When the doors are opened in particular manners (as in emergency situations), the slides are designed to inflate automatically for use by passengers and crew in exiting the craft. The slides are especially useful when a passenger cabin is substantially higher than the ground or other surface on which the aircraft rests, as otherwise passengers might be required, at their peril, to jump from the cabin (or wings) of the aircraft to the resting surface. 
     Descent speed of persons using an evacuation slide is, at least in part, a function of the angle (α) formed between the slide and the resting surface. Shallow angles may slow descent speeds below desired minimums, resulting in unacceptably-long evacuation times. Steep angles too may be unacceptable, either increasing descent speeds above desired maximums (thus increasing possibility of injuries to persons using the slides) or causing persons to refuse to use the slides entirely. 
     Static measurements may be made to assist designers in determining suitable lengths of inflated slides. For example, for an aircraft at rest on the ground with its landing gear deployed, the vertical distance between the ground and an exit door may readily be measured. By selecting a particular value for angle α, the designer readily may calculate, for this static case, the minimum slide length necessary for the slide to contact the ground. 
     Unfortunately, however, need to use an aircraft evacuation slide may arise in situations other than as described above. Failure of landing gear either to deploy or to support an aircraft could, for example, change the attitude of the aircraft such that one or more exit doors are higher (or lower) than in the static case. Similarly, if the resting surface of the aircraft is not uniformly horizontal, vertical heights of exit doors above the resting surface may differ from their norms. Yet additionally rupture and, for example, roll of the fuselage could increase beyond normal the height of some doors above even a level resting surface. As a consequence, a slide whose length has been selected based on static conditions may be of inadequate length when deployed for actual use. 
     U.S. Pat. No. 6,814,183 to Horvath, et al. seeks to resolve this issue by providing an extendable evacuation slide “deployable in either a foreshortened or lengthened configuration.” See Horvath, Abstract, 11. 2-3. Deployment configuration is determined automatically, so that it “does not rely on manual actuation or physical measurement of the distance to the ground.” See id., col. 2, 11. 28-29. Instead, an “electronic sensor such as an inclinometer” informs a control circuit as to “whether the aircraft is in a horizontal attitude, a nose down attitude or some other attitude.” See id., 11. 48-49; col. 5, 11. 6-8. Should the control circuit indicate the slide should be extended, a pyrotechnic cable cutter may be used to release the extendable portion of the slide. See id., Abstract, 11. 7-10. 
     Deployment state of the system of the Horvath patent is determined upon initial deployment. Stated differently, only one deployment decision is made based on information from the inclinometer: Either only the main section of the slide is inflated or both the main and extendable portions are inflated together. Consequently, if the signal from the inclinometer is erroneous (either electrically or practically), the extendable portion may inflate undesirably with no opportunity for correction. 
     For example, some evacuations follow collapse of the main (rearward) landing gear of aircraft, which event may lead to a phenomenon known as “tail tipping.” Such a tail tip subsequent to the inclinometer sensing aircraft attitude could adversely impact operation of the automatic system of the Horvath patent toward the rear of the aircraft. If the control circuit determines that both the main and extendable portions of the slide at a rear door should be inflated, they will do so together. However, any subsequent tipping of the aircraft tail could render the slide length too long for satisfactory use by passengers—i.e. the increased length would make angle α less than desired—with no way to prevent inflation of the extendable portion or automatically deflate it. By contrast, if only the main portions of slides at the forward doors are inflated based on the inclinometer readings, the subsequent tail tip may render them too short for use (i.e. angle α would be greater than desired) with no opportunity for extension. 
     Because the main and extendable portions of the slide of the Horvath patent are configured to be inflated together when signaled, no bulkhead or other mechanical fluid-interruption device is incorporated into the tubes of the slide. Instead, the extendable portion of the slide is laced into a pouch positioned at an end of the main portion, with the pyrotechnic cable cutter severing the lacings if extension is signaled to occur. As the lacings are external to the slide, however, they conceivably could be severed unintentionally (and undesirably) by sharp debris or heat. Need thus exists for extendable evacuation slides in which inflation of extendable portions occurs separately from inflation of the main portions and which are configured both to limit possibility of simultaneous inflation of the portions and to reduce possibility of the slides extending when not desired. 
     SUMMARY OF THE INVENTION 
     Systems of the present invention meet this need. Unlike slides of the Horvath patent, those of the present invention permit extendable portions to be inflated separately from main portions. Further, inflation of the extendable portions may occur following manual actuation. As a consequence, aircraft attitude changes subsequent to inflation of the main portion of a slide would not necessarily defeat its use, as a crew member (or passenger) may either thereafter cause inflation of the extendable portion or take no manual action, so that only the main portion inflates, as appropriate. 
     Although the extendable portions of the slide may be inflated separately from the main portions, they nevertheless may be integrally formed. Such integral formation may result in seamless tube structure of greater beam strength and reduced weight compared with alternative designs. Bulkheads may be positioned within the tubes between the main and extendable portions to block fluid flow from one to the other. Avoiding seams in the slide surfaces may allow users to retain their speeds of descent while transitioning from the main to the extendable portions. 
     An additional aspect of the present invention may include utilizing separate inflation systems for the main and extendable portions of the slides, with distinct fluid reservoirs, hoses, and aspirators being assigned to each. A quick release system for the extendable portion may facilitate stowage and restraint of that portion when unneeded. Lacings or snaps may, if desired, form part of the quick release system. Also, the floor of the extendable portion itself may be made of material selected so that no separate protective cover is needed. 
     It thus is an optional, non-exclusive object of the present invention to provide extendable evacuation slides principally, although not exclusively, for aircraft. 
     It is another optional, non-exclusive object of the present invention to provide evacuation slides having separately inflatable main and extendable portions. 
     It is also an optional, non-exclusive object of the present invention to provide evacuation slides in which inflation of an extendable portion may be actuated manually. 
     It is a further optional, non-exclusive object of the present invention to provide evacuation slides in main and extendable portions that may be integrally formed. 
     It is, moreover, an optional, non-exclusive object of the present invention to provide evacuation slides in which internal bulkheads prevent fluid flow between the main and extendable portions. 
     It is an additional optional, non-exclusive object of the present invention to provide evacuation slides in which a quick release system may be used for the extendable portion. 
     Other objects, features, and advantages of the present invention will be apparent to those skilled in the appropriate fields with reference to the remaining text and the drawings of this application. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an isometric view of an exemplary evacuation slide system of the present invention. 
         FIG. 2  is a generally side view of a portion of the slide system of  FIG. 1  shown with a slide in an unextended state. 
         FIG. 3  is a generally side view of a portion of the slide system of  FIG. 1  shown with the slide in an extended state. 
         FIG. 4  is a cross-sectional view similar to  FIG. 3  showing, in broken lines, an internal bulkhead useful as part of the slide system of  FIG. 1 . 
         FIGS. 5A-B ,  6 A-B, and  7 A-B present various views of an alternate evacuation slide system of the present invention, with each of the “A” drawings illustrating a slide in an unextended state and each of the “B” drawings illustrating the slide in an extended state. 
         FIG. 8  illustrates a containment wrapper as configured in the (unextended) slide system of  FIG. 5A . 
         FIG. 9  illustrates the containment wrapper of  FIG. 8  as configured in the (extended) slide system of  FIG. 5B  together with a transverse tube of the extension portion of the system. 
         FIGS. 10A-C  illustrate portions of the inflation system for the extension portion of the system of  FIG. 5B . 
     
    
    
     DETAILED DESCRIPTION 
     Illustrated in  FIGS. 1-4  is slide system  10  consistent with the present invention. System  10  includes at least one inflatable evacuation slide  14 . System  10  also may include conventional (or other) equipment for inflating slide  14 , examples of which include compressed gas cylinders, gas-generating pyrotechnic devices, and combinations of these types. 
     Head end  18  of slide  14  typically is secured to the aircraft or other structure from which it depends. A girt may be used to effect this securing, although other attachment means conceivably could be used instead. Generally, though, for use in connection with an aircraft, slide  14  is positioned so that head end  18  is connected at or adjacent an exit of the aircraft (e.g. a door or, possibly, a window). 
     Slide  14  may include a main portion  20  comprising at least two inflatable upper tubes  22  and  26 . The upper tubes  22  and  26 , when inflated, are generally parallel and may extend from head end  18  to foot end  30 . One or more inflatable transverse tubes  34  may be placed between upper tubes  22  and  26 , both to space the tubes  22  and  26  and to provide greater torsional stability to slide  14  when deployed. Included among these transverse tubes is one (labelled  34 A) positioned near foot end  30  of tubes  22  and  26 . Panels also may extend between upper tubes  22  and  26  to provide sliding surfaces for persons utilizing slide  14 . 
     Lower tubes, such as tubes  40  and  42 , may (when inflated) help support upper tubes  22  and  26  of slide  14 . Lower tubes  40  and  42  preferably extend parallel to upper tubes  22  and  26  and are inflated together with the upper tubes  22  and  26 . Lower tubes  40  and  42  also may be spaced by one or more transverse tubes  46 , of which several are shown in  FIG. 1 . Of course, other support structures additionally may be employed as appropriate or desired. 
     Depicted in  FIG. 1-2  is extension portion  37  comprising upper extension portions  48  and  50  of, respectively, upper tubes  22  and  26  and lower extension tubes  38  and  39 . Upper extension portions  48  and  50  preferably are integral continuations of respective upper tubes  22  and  26 . They preferably are inflated separately from upper tubes  22  and  26 , however. Indeed, in some embodiments of system  10 , extension portions  48  and  50  have dedicated inflation systems including, for example, dedicated gas reservoirs, hoses, and aspirators. Generally gas-impervious bulkheads (such as bulkhead  52  shown in broken lines in  FIG. 4 ) present within the tubes may be used to divide upper tubes  22  and  26  from the upper extension portions  48  and  50 , permitting separate inflation of the upper extension portions  48  and  50 . Transverse tube  34 A preferably is of reduced height as compared to other tubes  34 , reducing the possibility of disrupting progress of persons as they slide onto the extended part of slide  14 . 
     As illustrated in  FIG. 2 , extension portion  37 , when not inflated, may fold underneath upper tubes  22  and  26  back toward head end  18 . If appropriate, distal end  54  of extension portion  37  may be connected to main portion  20  (as, for example, by a quick release mechanism) when extension portion  37  is uninflated. Upon inflation, however, extension portion  37  unfolds so that distal end  54  extends away from head end  18 , beyond foot end  30  of upper tubes  22  and  26 . Consequently, extension portion  37  thus, upon inflation, increases the useful length of main portion  20  of slide  14 . 
       FIG. 1  depicts a transverse tube  62  connecting upper extension portions  48  and  50  at extended foot end  66  (see also  FIG. 3 ). A similar transverse tube  41  may connect lower extension tubes  38  and  39 . Inflatable components of extension portion  37  preferably are inflated together should the length of slide  14  need to be extended. 
     Shown in  FIGS. 5A-B ,  6 A-B, and  7 A-B is alternate exemplary slide system  110  consistent with the present invention. System  110  may include at least one inflatable evacuation slide  114  as well as equipment for inflating the slide  114 . Like head end  18  of slide  14 , head end  118  of slide  114  may be secured to the aircraft or other structure from which it depends when deployed. 
     Main portion  120  of slide  114  preferably comprises at least two inflatable upper tubes  122  and  126  extending from head end  118  to foot end  130 . When inflated, at least portions of tubes  122  and  126  are generally parallel (as depicted in  FIGS. 5A-B  and  7 A-B). One or more transverse tubes  134  may be placed between tubes  122  and  126  as both spacers for the tubes and torsional stabilizers for slide  114  when deployed. In the version of system  110  illustrated in  FIG. 5A , one transverse tube (labelled  134 A) is present at or near foot end  130 , while another such tube  134  is present at or near head end  118 . One or more panels  121  (see  FIG. 8 ) also may extend between upper tubes  122  and  126  to provide sliding surfaces for persons utilizing slide  114 . 
     Main portion  120  may also include one or more (and preferably two or more) lower tubes  140  and  142 . Lower tubes  140  and  142  may help support upper tubes  122  and  126  and preferably extend generally parallel thereto. Likewise, lower tubes  140  and  142  preferably are inflated together with the upper tubes  122  and  126 . One or more transverse tubes  146  may connect (and thereby space) lower tubes  140  and  142 . 
     Depicted in  FIGS. 5B ,  6 B, and  7 B is slide system  110  in its extended state. Slide  114  includes extension portion  137  comprising upper extension portions  148  and  150  of, respectively, upper tubes  122  and  126  as well as lower extension tubes  138  and  139 . One or more panels preferably extend between upper extension portions  148  and  150  as well to provide sliding surfaces for persons utilizing slide  114  in its extended state. 
     Extension portion  137  additionally may define or comprise distal end  154 , extended foot end  166 , and one or more transverse tubes  162  connecting upper extension portions  148  and  150 . As illustrated especially in  FIGS. 5B and 7B , at least one version of extension portion  137  includes a transverse tube  162  at or adjacent extended foot end  166  and another (labelled  162 A) between distal end  154  and extended foot end  166 . 
     Unlike lower extension tubes  38  and  39  of  FIG. 1 , lower extension tubes  138  and  139  preferably taper inward toward extended foot end  166 , thus resembling certain type of fork tines. They additionally may lack any transverse tube near extended foot end  166 . Those skilled in the appropriate field will, however, recognize that extension portion  137 , and any portion of it, may be configured differently than is illustrated in  FIGS. 5B ,  6 B, and  7 B. 
     Upper extension portions  148  and  150  preferably are (but need not necessarily be) integral continuations of respective upper tubes  122  and  126 . Again, though, upper extension portions  148  and  150  preferably are inflated separately from upper tubes  122  and  126 . They preferably are, however, inflated together with all other inflatable components of extension portion  137 . If upper extension portions  148  and  150  are continuations of but inflated separately from upper tubes  122  and  126 , bulkheads (such as generally gas-impervious bulkhead  52  of  FIG. 4 ) may be present as dividers. 
     Either or both of transverse tubes  134 A and  162 A beneficially may be of reduced height as compared to one or more of the other tubes  134  and  162 . This height reduction reduces the possibility of tubes  134 A and  162 A disrupting progress of persons as they slide onto extension portion  137  of slide  114 . By contrast, any panel extending across upper extension portions  148  and  150  adjacent extended foot end  166  may include a urethane coating or other friction-increasing agent so as to decelerate sliding passengers approaching extended foot end  166 . 
     Illustrated in  FIGS. 8-9  is, among other things, containment wrapper  170 . Wrapper  170 , which may comprise fabric or any other flexible material, functions to assist in retaining extension portion  137  in place relative to the remainder of slide  114  when not deployed. First end  174  of at least part of wrapper  170  may be relatively permanently attached to a transverse tube  146  or other portion of the understructure of main portion  120 . By contrast, second end  178  is attached to panels  121 , so that at least part of wrapper  170  wraps around foot end  30  as shown in  FIG. 8 . Folding or packing (uninflated) extension portion  137  adjacent or within main portion  120  thus permits wrapper  170  to retain it in place. In this situation depicted in  FIG. 8 , wrapper  170  itself may be coated with urethane or otherwise made or modified so as to increase its frictional resistance to motion of sliding passengers. 
     Attachment of second end  178  to panels  121  preferably is not permanent—i.e. second end  178  may be removed from panels  121  upon application of suitable force. As a consequence, as extension portion  137  inflates, second end  178  detaches from panels  121  to allow slide  114  to expand to its extended state. Because first end  174  remains attached to understructure of main portion  120 , following detachment second end  178  may dangle below slide  114  (see  FIG. 9 ) and thus avoid creation of any impediment to persons utilizing the slide  114  for evacuation purposes. 
       FIGS. 10A-C , finally, depict aspects of inflation system  182  for extension portion  137 . System  182  may comprise at least aspirator  186  and “snorkel” or inflation tube  190 . Aspirator  186  beneficially may be positioned near head end  118  of slide  114  and receive pressurized fluid (e.g. air) from a source thereof when extension portion  137  is to be deployed. Because both aspirator  186  and extension portion  137  communicate with tube  190 , pressurized fluid passing through the aspirator  186  travels within the tube  190  to extension portion  137  so as to inflate it. Further, because some of the fluid will remain within tube  190  (thus inflating it too), the diameter of tube  190  preferably is substantially smaller than the maximum diameter of, for example, any of upper extension portions  148  or  150  or lower extension tubes  138  or  139 . 
     The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of the present invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of the invention. For example, although various elongated structures are referred to herein as “tubes,” they need not necessarily have circular transverse cross-section. Additionally, the contents of the Horvath patent are incorporated herein in their entirety by this reference.