Abstract:
A wearable load supporting system has a rigid back plate which is supported over the shoulders of a user, and which may be a part of a backpack or carrier system, or may be incorporated within a ballistic vest. The back plate has an upper segment which extends downwardly over padding, and which terminates in a downwardly and rearwardly extending lower segment. A waist belt is secured around the user&#39;s waist, and mounts a rearwardly facing rigid waist plate. When the user is upright, a high friction surface on the lower segment of the back plate engages a high friction surface on the waist plate, to thereby transfer vertical loads from the back plate to the waist plate. However, if the user bends forwardly, the connection between the high friction surfaces is broken. Although the loads are no longer transferred to the user&#39;s waist, neither is the user&#39;s mobility restricted.

Description:
STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT  
       [0001]     The U.S. Government has a paid-up license in this invention and the right in limited circumstances to require the patent owner to license others on reasonable terms as provided for by the terms of contract No. DAAD16-01-C-0061 awarded by the US Army Robert Morris Acquisition Natick Contracting Division of the United States Department of Defense. 
     
    
     CROSS REFERENCES TO RELATED APPLICATIONS  
       [0002]     Not applicable.  
       BACKGROUND OF THE INVENTION  
       [0003]     The present invention relates to systems for transporting loads in general, and more particularly to systems for human back-mounted support of loads.  
         [0004]     Although significant loads are conventionally transported by automated machinery such as automobiles, airplanes, boats and trains, there are still important applications where it is necessary for a single person, unassisted, to transport material and supplies which must be readily at hand. Explorers, sport travelers, mountaineers, park rangers, and others who travel away from established roads must often carry loads over terrain which is impassable by automated equipment and which may not even be accessible by pack animals. Soldiers and police officers also must bring supplies, weapons, and materiel into unpaved regions under challenging conditions.  
         [0005]     Backpacks and haversacks provide containers which are supported on one or both shoulders, and allow the user to carry significant loads of 30-100 pounds or more. External frame backpacks employ stiff tubular supports for the load, and commonly have a waist belt which secures the pack at the waist to remove some of the load from the user&#39;s shoulders and place it on the user&#39;s waist or hips. By transferring some of the load to the user&#39;s waist, the weight on the user&#39;s back is reduced, and hence the carrying of greater loads for greater distances is made possible. However, by strapping the pack to the waist, the wearer is limited in his flexibility and mobility.  
         [0006]     When conditions call for rapid or limber movements, a backpack which is fixed to the wearer&#39;s waist can be a distressing impediment; and, in the case of military or police use, hazardous.  
         [0007]     What is needed is carrier system which aids a user in extended transport of loads, while permitting unrestricted movement on demand.  
       SUMMARY OF THE INVENTION  
       [0008]     The carrier system of this invention transfers loads from a shoulder mounted assembly to a waist mounted assembly by purely frictional engagement between two stiff structures. At any time the user can bend forward to instantly break the frictional connection. The wearable load supporting system has a rigid back plate which is supported over the shoulders of a user, and which may be a part of a backpack or carrier system, or may be incorporated within an armored vest. The back plate has an upper segment which extends downwardly over padding, and which terminates in a downwardly and rearwardly extending lower segment. A waist belt is secured around the user&#39;s waist, and mounts a rearwardly facing rigid waist plate. When the user is upright, a high friction surface on the lower segment of the back plate engages a high friction surface on the waist plate, to thereby transfer vertical loads from the back plate to the waist plate. However, if the user bends forwardly, the connection between the high friction surfaces is broken. Although the loads are no longer transferred to the user&#39;s waist, neither is the user&#39;s mobility restricted. The high friction surfaces may be natural or artificial rubber, or mechanically engaging surfaces arranged such that sliding motion between the back plate and the waist plate are restricted by the friction load transfer surfaces, without restricting the pulling away of the back plate from the waist plate in a direction generally perpendicular to the engaged friction load transfer surfaces.  
         [0009]     It is a feature of the present invention to provide a load carrying system which effectively transfers a portion of the load to the waist of the user or permits the user to lean forward without restriction.  
         [0010]     It is another feature of the present invention to provide a ballistic protection vest which incorporates load transfer capabilities.  
         [0011]     Further features and advantages of the invention will be apparent from the following detailed description when taken in conjunction with the accompanying drawings.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a side elevational view, partially broken away in section, of the pack support system of this invention, with an alternate position of the user shown in phantom view.  
         [0013]      FIG. 2  is an exploded isometric view, partially broken away, of the system of  FIG. 1 .  
         [0014]      FIG. 3  is an isometric view of the fastener which connects the pack to the shell of the system of  FIG. 1 .  
         [0015]      FIG. 4  is a schematic side elevational view showing the fastener of  FIG. 3  while supporting loads.  
         [0016]      FIG. 5  is a schematic side elevational view of the fastener of  FIG. 4  being disengaged.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]     Referring more particularly to  FIGS. 1-5 , wherein like numbers refer to similar parts, a pack support system  20  is shown in  FIGS. 1 and 2 . The pack support system  20  has a shoulder mounted assembly  26  and a waist mounted assembly  28  which cooperate to transfer loads from the shoulder mounted assembly to the waist mounted assembly under certain conditions.  
         [0018]     The system  20  is illustrated as incorporating a ballistic protection vest, such as the one disclosed in U.S. patent application Ser. No. 10/255,157, filed Sep. 25, 2002, the disclosure of which is incorporated by reference herein. The vest may incorporate soft armor and hard armor plates. The shoulder mounted assembly has a rigid back plate  30 . The rigid back plate is preferably used in conjunction with a load transferring shell  48  or carapace. The shell is formed by two side vest sections  34  which are connected to the front plate and the back plate. The shell serves to evenly distribute the supported loads over the user. The back plate  30  is fastened to the rear of the shell  48  by adjustable straps. The straps may be adjustably received within loops, or a slot and tab arrangement may be employed. It should be noted that the rigid plates will typically be encased in fabric pockets, which make it possible to readily attach fabric straps and fasteners thereto. The shell  48  may be formed of flexible, thin aluminum, or PVC plastic, or High Density Polyethylene or, in ballistic applications, of the ballistic material known as Spectra. It could be a 3-D molded sheet, or formed of flat sheet material into which bends have been formed.  
         [0019]     The side vest sections  34  of the shell  48  have two shoulder straps  32  connected to two flexible vest side parts  34  which are connected to a front plate  36 , best shown in  FIG. 2 . In a ballistic protection vest, the front plate  36  and the back plate  30  will have ballistic protection characteristics. If only the load carrying features of the system are required, the rigid front plate need not be included, but in any event the back plate  30  will be of rigid material. Thus, although the back plate  30  may be composed of a hardened lay-up of ballistic materials, it could also be formed of aluminum, carbon fiber, fiberglass, a thermoplastic material such as ABS plastic {fraction (1/8)} inch thick or thicker, and it could be reinforced with glass fibers. Although there may be a small amount of flex in the plate, it should be generally rigid and not floppy like a fabric. The back plate  30  may also be a composite structure, for example plastic reinforced with metal spars, such as ABS plastic with {fraction (1/8)} inch thick aluminum spars. As shown in  FIG. 2 , the back plate has a distinct curvature about several horizontal axes, as discussed in more detail below. It may also have a slight curvature about a vertical axis, to conform somewhat to the back of a user  21 , although that is not necessary. Although shown as generally featureless, the back plate could also be formed with stiffening ribs or corrugations, to permit increased stiffness at reduced weight.  
         [0020]     The back plate  30  is connected by the vest side parts of the shell to the shoulder straps  32 , and hangs downwardly in engagement with the user&#39;s back. The shell is made of a material similar to the shoulder strap material. The back plate is cushioned against the user&#39;s back by one or more back pads  38  on the vest parts  34 . The back pads  38  may be of conventional padding material, such as closed cell foam, or a combination of open and closed cell foam. The shoulder straps and the vest parts  34  are not as stiff as the back plate, but are not as loose as fabric. The vest parts  34  may be formed of, for example, polyethylene or a flexible plastic material, similar to a football uniform shoulder pad material, which is capable of transferring some load, and distributing it evenly over the wearer&#39;s shoulders. Shoulder pads  40  of material similar to the back pads  38  cushion the shoulder straps  32  where they engage the user.  
         [0021]     As best shown in  FIG. 1 , the back plate has an upper segment  42  which extends downwardly and frontwardly, as worn, and is supported by the back pads  38  against the user&#39;s back. The upper segment  42  may be somewhat concave as it faces frontwardly, such that it has a top portion  44  which projects frontwardly to extend along the upper portion of the wearer&#39;s back. The back plate  30  has a lower segment  46  which extends downwardly and rearwardly from the upper segment. The angle between the upper segment  42  and the lower segment  46  of the back plate is less than 180 degrees, and more than 90 degrees, preferably about 120 degrees.  
         [0022]     The lower segment  46  of the back plate extends rigidly from the upper segment  42 , and is faced with a high friction material which defines a frontwardly facing friction load transfer surface  50  which is positioned to engage against a similar high friction material on the waist mounted assembly  28 . Although the upper segment  42  may have a slight curve about a generally vertical axis, the lower segment is preferably without a curve.  
         [0023]     The waist mounted assembly  28 , as shown in  FIG. 2  has a flexible fabric belt  52  which may have a conventional quick release buckle fastener  54  in front, and which loops around the user&#39;s waist. Fixed to the rear of the flexible belt  52  is a rigid waist plate  56 , which may be made of a material similar to the material from which the back plate is formed. If the back plate lower segment has a curve about a generally vertical axis, then the rigid waist plate may have a matching curve. However, both the back plate lower segment and the waist plate  56  are preferably planar plates. A waist pad  58  is mounted to the belt  52  frontwardly of the waist plate  56 , and cushions the bearing of the waist plate against the user  21 . The waist plate  56  is faced with a high friction material which defines a rearwardly facing friction load transfer surface  60  which is positioned to engage against the similar high friction material on the lower segment  46  of the back plate. As shown in  FIG. 1 , the waist plate  56  faces generally rearwardly, and may face slightly upwardly, while the back plate lower segment faces frontwardly and slightly downwardly.  
         [0024]     The material which presents the high friction load transfer surfaces  50 ,  60 , on the lower segment  46  of the back plate  30  and on the waist plate  56 , may be a material with an inherently high coefficient of friction such as synthetic or natural rubber, or urethane, or the rubber from which automobile tires are made, or some viscoelastic material, or it could be the GREPTILE™ material formerly manufactured by 3M of Minneapolis, Minn. Alternatively, the material may not be inherently high friction, but may highly textured mechanical structure formed thereon which causes two sheets of the formed material to resist shear, but to have substantially no resistance to being peeled apart or pulled apart. For example, the material may be formed with microscopic projecting fingers, or small pyramids which mate with one another.  
         [0025]     A pack  62  is removably attached to the system  20  by straps or other connectors which fasten it to the shell. Adjustable upper straps  64 , and lower straps  66  connect the pack to the side vest parts and the front plate, as shown in  FIG. 2 . Hence, in use, the pack is secured to the shell  48  and restrained from moving freely with respect to the user&#39;s upper body. The secure engagement of the pack to the shell prevents its movement with respect to the back plate. It will be noted that the pack  62  is not fastened directly to the user&#39;s waist, but only through the frictional connection of the high friction load transfer surfaces  50 ,  60 . The pack may be of a modular design, so that various packs of different configuration can be received on the same back plate, permitting the rapid exchange of loads between various users.  
         [0026]     The conrection between the pack  62  and the shell  48  may be provided by a variety of conventional fastener such as carabiners, or sideways buckles, but the connection is preferably provided by quick release fasteners  68 , such as those shown in  FIGS. 3-5 . Each fastener  68  has a plastic body  70  which is generally C-shaped having a first member  72  connected by an end piece  74  to a second member  76  spaced from the first member. A semi cylindrical slot  78  is defined between the first member  72  and the second member  76  within the end piece  74 , the slot is dimensioned to tightly engage a particular cylindrical bar. The second member  76  defines a ramp  80  which leads into the slot  78 . The body  70  may be formed of nylon, or delrin plastic material, and will therefore elastically deform to engage the cylindrical bar  82  of a metal ring  84 . The ring  84  may be connected by a fabric loop  86  in a conventional fashion to the shell  48 . The first member  72  has an upper opening  88  which receives a strap upon which a load to be carried is applied. A forward opening  90  is formed in the body end piece  74  which receives a handhold loop  92 . As shown in  FIG. 4 , in use, loads are applied by a strap to the first member  72  of the body  70  and are carried thereby to the ring  84  and from there to the fabric loop  86  and the shell  48 . When it is desired to disconnect the fastener  68 , the user engages the handhold loop  92  and pulls away from the ring  84 , causing the body  70  to pivot about the ring bar  82  until the bar may be disengaged from the semicylindrical slot  78 . The fasteners  68  may be positioned on the upper portion of the shoulder straps or the shell front to receive the straps  64 , as well as on the front plate of the shell to receive the sidewardly and rearwardly extending straps  66 .  
         [0027]     As shown in  FIG. 1 , when the user  21  stands upright, with the pack  62  affixed to the back plate  30 , the friction load transfer surfaces  50 ,  60 , on the lower segment  46  of the back plate  30  and on the waist plate  56  engage one another, and, because of the high frictional engagement between the two surfaces, there is no shear between the engaged surfaces, and hence vertical loads are transferred from the back plate to the waist plate and hence the waist belt  52  and to the user&#39;s waist. However, if a particular orientation becomes uncomfortable, the user need only lean forward slightly, as indicated in the phantom view of  FIG. 1 , to completely separate the back plate  30  from the waist plate  56 . The connection between the back plate and waist plate may then be adjusted when the user again stands upright. The high frictional engagement between the surfaces provides substantially no resistance to pulling or peeling apart the two plates, and hence they are readily and easily adjusted in their engagement. Moreover, if the user needs to make a sudden forward bending movement, the connection between the shoulder mounted assembly and the waist mounted assembly provides no impediment to this motion. This freedom of movement can be especially important in military and police maneuvers where threats may appear unexpectedly and suddenly from any direction, requiring a rapid response. Depending on how high the frictional engagement is between the friction load transfer surfaces, a high level of the back load can be successfully transferred to the waist.  
         [0028]     It is understood that the invention is not limited to the particular construction and arrangement of parts herein illustrated and described, but embraces all such modified forms thereof as come within the scope of the following claims.