Abstract:
A buffer stop assembly for engagement within cargo aircraft to resist cargo movement. The buffer stop assembly comprises a horizontal member selectively engageable to the aircraft and a substantially vertical member resistant to movement by aircraft cargo. The members are mounted to each other. Preferably the panel mounting allows the vertical member to be moved between an extended position and a transport position overlying the horizontal member.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to an aircraft cargo system. More particularly, the present invention relates to a buffer stop assembly for use in an aircraft cargo system. 
     The aerial delivery of supplies to a ground based area is well known. Often the container delivery system (CDS) is used to accomplish such aerial deliveries. The container delivery system comprises an aircraft configured to include an aerial delivery rail system that include floor having parallel forward to aft rails, parallel rows of forward to aft rollers and a center channel therebetween. The side rails, rollers and center channel extend from a door in the aft section of the aircraft toward the front. See, for example, Technical Outline T. O. 1C-130A-9, Section VIIC for more information. 
     The supplies are enclosed within a net or “container” that is attached to a folded parachute canopy. The container and canopy are attached to a base or skidboard. Each base with attached container and canopy is loaded into the aircraft and slid forward on the rollers. The first container moves forward to contact a forward stop. Each subsequent container moves forward to contact the preceding container. Each container is secured to the aircraft to prevent shifting during flight. 
     During use the aircraft flies to a desired drop off point. The aircraft aft section door is opened, each container restraint is loosened and the containers are moved rearward on the rails to gravity exit from the aircraft. Once outside the aircraft, the canopy deploys and the container descends to the ground. 
     A CDS container can weigh up to 2,328 pounds and some aircraft can hold a total of 16 containers for a maximum cargo load of 37,248 pounds. The forward stop must prevent this load from shifting forward during flight to prevent damage to the aircraft and injury to the flight crew. It should be noted that the forward stop must be capable of preventing forward movement of the entire container cargo even when the cargo is under an acceleration of three times the force of gravity. 
     Currently, the forward stop is constructed from two type IV aerial delivery pallets permanently configured in an L-shape. While the type IV forward stop was successful, its configuration was bulky and difficult to transport. In addition, type IV aerial delivery panels are no longer manufactured and have become very difficult to procure. Therefore, a forward stop utilizing such panels can not presently be manufactured. 
     SUMMARY OF THE INVENTION 
     The invention in a preferred form is a buffer stop assembly for use as a forward stop in an aircraft. The inventive buffer stop assembly can be used without requiring changes to aircraft presently configured for the container delivery system. The buffer stop assembly comprises a horizontal member preferably including a type V aerial delivery panel extrusion having a side rail, strut support, and end member mounted to each side and roller pads mounted to the lower surface. The side rails and roller pads are configured and positioned to interact with existing rails, rollers and center channel of the aircraft aerial delivery rail system. 
     A vertical member preferably including a second type V panel extrusion is arranged substantially vertically and perpendicularly to the horizontal panel. The vertical member comprises an end member and sidepiece mounted to each side of the panel. Each sidepiece is connected by a hinge block and a compression member to a respective horizontal member side rail. A plurality of inclined struts join the perpendicular panels into a rigid assembly. A center strap bisects each planar face of the vertical panel and extends beyond the vertical panel lower edge. The center strap extending portions are mounted to an L-shaped junction. 
     For transportation, the struts and bolts fixing a sidepiece to its respective hinge block can be removed to allow the vertical member to pivot around the compression member to a position overlying the horizontal member. Naturally, the folded position uses considerably less valuable aircraft cargo space than the extended position. When the buffer stop assembly is to be used as a forward stop, the vertical panel is extended around the pivot, each strut is reinstalled between the two panels and the side pieces are bolted to their respective hinge blocks. The extended buffer stop assembly is placed on the aircraft with the vertical panel facing aft, the horizontal member facing forward and with the roller pads positioned over the rollers. The buffer stop assembly is pushed forward to a desired position. In this position, existing aircraft rail system detents will lock into indents in each side rail. If further restraint is needed, a “H” block or the L-shaped junction can be bolted to the existing aircraft center channel. Alternatively, or in addition thereto, devises can be mounted to the buffer stop assembly and attached via tie-downs to aircraft mounted anchor points. 
     An object of the invention is to provide a buffer stop assembly using commercially available panel extrusions. 
     Another object of the invention is to provide a container delivery system forward restraint which can be folded for ease of transportation. 
     A further object of the invention is to provide a buffer stop assembly that can restrain a load of more than 30,000 pounds from forward movement during rapid deceleration. 
     A still further object of the invention is to provide a buffer stop assembly comprising commercially available aerial delivery panels which can be used in existing aircraft aerial delivery rail systems. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects and advantages of the invention will be evident to one of ordinary skill in the art from the following detailed description made with reference to the accompanying drawings, in which: 
     FIG. 1 is a perspective view from the forward end of an extended embodiment of an inventive buffer stop assembly; 
     FIG. 2 is a perspective view from the aft end of an extended embodiment of an inventive buffer stop assembly; 
     FIG. 3 is a perspective view of a folded embodiment of an inventive buffer stop assembly; 
     FIG. 4 is a front elevational view, partly in phantom, of a portion of an embodiment of the horizontal member of an inventive buffer stop assembly; and 
     FIG. 5 is a top plan view of a portion of an embodiment of the horizontal member of an inventive buffer stop assembly with an aircraft mounted detent engaged therein. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to the drawings, wherein like numerals designate like components throughout the Figures, a buffer stop assembly is generally designated  10 . As used herein, the directions forward and aft, shown in FIG. 1, refer to the positions of the buffer stop assembly  10  with respect to the front and rear respectively of the aircraft. As shown in FIG. 1, the buffer stop assembly  10  is comprised of a first horizontal member  12  and a second vertical member  14 . Each member includes a panel  16 ,  18 , respectively. With reference to FIG. 4 the panels  16 ,  18  (only panel  16  shown in FIG. 4) are preferably lightweight structures comprising spaced exterior sheets  20 ,  22  with a plurality of substantially hollow load support structures  24  therebetween. Type V aerial delivery pallet panel extrusions are known to be satisfactory for use as panels for the inventive buffer stop assembly. Type V panel extrusions are 24 inches long by 100 inches wide and are described in military specification MIL-P-44115B, dated Mar. 31, 1992, and drawings 11-1-2780, platform, Airdrop, Type V (available from U.S. Army Natick Research, Development, and Engineering Center, ATTN: 
     STRNC-UX, Natick, MA 01760-5017); the disclosures of which are incorporated by reference herein. Naturally, other panels could also be used. 
     With reference to FIGS. 1 and 2, the horizontal member  12  includes a plurality of roller pads, each  26 . The roller pads  26  are mounted to a panel lower surface  28  and span the length of the panel  16 . Preferably the roller pads  26  extend beyond the aft end  30  of the panel. A plurality of reinforcing gussets, each  32 , are mounted to a panel upper surface  34  and substantially span the length thereof. The reinforcing gussets may be L-shaped structures placed in a back to back configuration and mounted to the panel. The gussets may include strut mounts  33 . A stop block  36  is mounted to the first panel  16  at about the center of the forward edge. 
     As shown best in FIG. 4, an end member  38  is adjacent each side  40 ,  42  of the first panel  16 . FIG. 4 illustrates only one side  40  of the horizontal member  12 . It should be understood that while only a single side of the horizontal member is described, the opposing side will typically be a mirror image having substantially equivalent structure. The end member  38  preferably comprises an E-shaped cross-section with the upper and lower arms  44 ,  46  extending adjacent the horizontal panel upper  34  and lower  28  surfaces. The end member  38  typically extends along substantially the entire length of the horizontal panel side. The end member  38  is mounted to the panel  16  by, for example, rivets extending through the outermost arms  44 ,  46  into the panel  16 . The end member  38  includes support pads  48 ,  50  adjacent the outermost arms that function in concert with a center arm  52  to space the end member  38  from the panel side  40 . A plurality of fasteners  56  such as, for example, nuts are mounted along the length of the end member within an upper cavity  58  defined between the end member upper  44  and center  52  arms. The end member  38  preferably comprises an outwardly facing nose or flange  60 . As used herein, inward and outward respectively refer to directions toward and away from a panel. 
     A strut support  66  is adjacent the outward side of the end member  38 . The strut support  66  is preferably substantially rectangular with an axially extending recess  68 ,  70  defined in each side. When the strut support  66  is positioned adjacent the end member  38 , the flange  60  is engaged within the inwardly facing recess  68 . A strut mount  72  (broken off in FIG.  4  and shown best in FIGS. 1 and 2) extends upwardly from each strut support  66 . Typically, the strut mount  72  is trapezoidally shaped. The strut support  66  is mounted toward the front of panel  16  and typically extends along only a portion of the panel side. 
     A side rail  78  is comprised of inwardly  80  and outwardly  82  facing flanges and a vertical mount  84  substantially perpendicular thereto. The outwardly facing flange  82  defines a plurality of indents  86  (shown best in FIG.  2 ). The inwardly facing flange  80  comprises vertical  88  and horizontal  90  support pads that engage the end member  38  and a horizontal mount  92  that engages the roller pad  26 . The horizontal mount  92  is preferably mounted to the roller pad  26 . Typically, a fastener is placed within aligned apertures (not shown) defined within the roller pad  26  and horizontal mount  92  and secured to a mating fastener (not shown) mounted within the horizontal panel. The vertical mount  84  preferably includes an inwardly facing nose or flange  94  that engages the outwardly facing recess  70  defined within the strut support  66 . 
     A fastener is positioned within aligned apertures (not shown) defined within the vertical mount  84  and strut support  66  and secured to the nut  56  mounted within the end member upper cavity  58 . The side rail  78  extends beyond the panel side width. 
     Since the strut support  66  does not typically extend the full length of the panel  16 , a space is defined between the side rail  78  and end member  38  for part of the panel length as shown best in FIG. 2. A side rail bushing  98  may be positioned between the side rail  78  and end member  38 . A fastener is positioned within aligned apertures (not shown) defined within the vertical mount  84 , side rail bushing  98  and end member  38  and secured to a nut mounted within the end member upper cavity  58 . A clevis  100  may be installed around the side rail bushing  98 . The side rail bushing  98  and fastener function to additionally secure the side rail  78  to the panel  16  while also providing a tie down position for the buffer stop assembly  10  as later described. 
     As shown best in FIGS. 2 and 3, a hinge block  104  is positioned toward the aft portion of the side rail  78 . Each hinge block  104  comprises an inwardly facing indentation (not shown) and an aperture connecting the indentation to the hinge block outward face  106 . The outward face  106  of the hinge block  104  defines a recess  108  that engages the inward-facing flange  94  of the vertical mount  84 . The hinge block is mounted to the side rail with, for example, fasteners. 
     In the buffer stop assembly extended position shown in FIGS. 1 and 2, the vertical member  14  is preferably arranged substantially perpendicular to the horizontal member  12 . The vertical member  14  comprises a panel  18  having an aft facing thrust face  112  and a forward facing reinforcing face  114 . 
     In a manner similar to that described above, an end member  116  is mounted to each side of the vertical panel  18 . A sidepiece  118  is mounted to each end member  116  and extends downward beyond the vertical panel  18  lower edge. Each sidepiece  118  includes a strut mount  120  toward the upper end and an L-shaped lower portion  122  with a forward facing lower leg  124 . Each lower leg comprises an aperture (not shown) connecting an inward face to an outward face. A forward center strap  128  is mounted to the reinforcing face  114  of the vertical panel  18  and extends from the panel upper edge to beyond the panel lower edge. An aft center strap  130 , shown best in FIG. 2, is spaced rearward from the forward center strap  128 , is mounted to the vertical panel thrust face  112  and extends from the panel upper edge to beyond the lower edge. The front and aft center straps  128 ,  130  are mounted at their respective lower portions to a junction block  132 . Preferably, the forward and aft center straps are mounted at approximately the center of the vertical member  14 . A plurality of reinforcing gussets, each  134 , is mounted to the vertical panel reinforcing face  114 . The reinforcing gussets  134  may be L-shaped structures placed in a back to back configuration. The gussets  134  may include strut mounts  136 . A plurality of deck rings  138  are mounted to the vertical panel thrust face  112 . The deck rings  138  function to provide another tie down position for the buffer stop assembly  10 . 
     Each sidepiece  118  lower portion is adjacent the inward face of a respective hinge block  104 . A compression member  140  is located within the indentations of opposing side rails and extends through the apertures of opposing sidepieces. The compression member  140  includes opposing ends defining apertures. A fastener is mounted through the indentation aperture in a hinge block  104  and secured in the respective compression member  140  end aperture. The compression member  140  functions as a transverse-reinforcing member for the buffer stop assembly. The vertical member  14  pivots around the compression member  140 . While the preferred embodiment for an inventive buffer stop assembly provides pivoting of the vertical member  14  with relation to the horizontal member  12 , it should be understood that other embodiments of the invention are contemplated wherein the vertical and horizontal members are permanently assembled such as by welding so that the members do not pivot. 
     With reference to FIGS. 1 and 2, a reinforcing strut  142  is mounted between the sidepiece strut mount  120  and side rail strut mount  72  at each side of the buffer stop assembly. Additional reinforcing struts  144  are mounted between corresponding reinforcing gusset strut mounts  33 ,  136  on the horizontal  16  and vertical  18  panels. Preferably, the buffer stop assembly comprises struts mounted to strut mounts between the upper edge of the vertical panel and forward edge of the horizontal panel as well as between the lower edge of the vertical panel and aft edge of the horizontal panel. While the struts  142 ,  144  may be mounted to the buffer stop assembly in a number of ways, use of bolts with self-locking nuts to fasten the strut to the strut mount has been found effective. Steps  148  may be mounted to a strut to help the aircrew move over the buffer stop assembly. 
     In operation, the extended buffer stop assembly is loaded onto an aircraft having an aerial delivery rail system. The buffer stop assembly is positioned with the vertical panel reinforcing face  114  toward the aircraft front section and the thrust face  112  toward the aircraft aft section. The roller pads  26  are located over rollers  152  mounted within the aircraft floor, each side rail outward flange  82  is positioned below an aircraft mounted rail  154  and the junction block  132  is positioned adjacent an aircraft mounted center channel  156 . The buffer stop assembly is pushed toward the front of the aircraft to a desired position. In this position, detents  150  mounted to the aircraft on each side of the buffer stop assembly will engage within indents  86  defined within the respective side rail  78 . See FIG.  5 . The engagement of detents  150  within side rail indents  86  and side rail  78  engagement with aircraft rails  154  is sufficient to allow the buffer stop assembly to resist a working force of up to 15,000 pounds applied to the thrust face in a forward direction. It should be understood that the system is designed to withstand the above working force under a forward acceleration of three times gravity. If resistance to working forces greater than 15,000 pounds is desired, additional restraint is preferably provided. The additional restraint may be provided as shown in FIG. 2 by mounting the junction block  132  and H block  146  to the aircraft center channel  156  using, for instance, fasteners. Alternatively, restraints such as tie downs or chains are mounted between the devises  100  mounted to respective side rail bushings  98  and deck rings  138  and aircraft anchor points (not shown). The additional restraints function to resist a working force of 37,248 pounds. The additional restraints are designed to withstand the above working force a forward acceleration of three times gravity. Naturally, both types of restraints could be used simultaneously. It should be understood that the aircraft mounted rails  154 , rollers  152 , center channel  156 , H block  146  and anchor points do not form part of the invention but are recited to help illustrate the best manner of making and using the invention. 
     To fold the buffer stop assembly for transport, the self-locking nuts and bolts are removed from the struts and strut mounts. The struts are removed from the strut mounts and placed in a storage bag along with the bolts. The nuts and bolts are removed from the hinge blocks and the bolts placed in the storage bag. The vertical member  14  may be pivoted around the compression member longitudinal axis and moved substantially parallel with the horizontal member  12 . To extend the buffer stop assembly the steps are reversed. Generally, a new set of self-locking nuts will be used each time the buffer stop assembly is extended to minimize the danger of the nuts working loose from vibration during transport and possible failure of the assembly. 
     While preferred embodiments of the foregoing invention have been set forth for purposes of illustration, the foregoing description should not be deemed a limitation of the invention herein. Accordingly, various modifications, adaptations and alternatives may occur to one skilled in the art without departing from the spirit and scope of the present invention.