Abstract:
A backpack includes a pair of contoured side rails and three separate molded plastic support members removably attached to the rails. The upper support member includes a structure for carrying much of the weight of the carry bag. The carry bag includes hook and loop fasteners on fabric strips for securing the bag to the rails. The upper support member and other support members include slots and ports for attaching various straps and pads. One of the support members includes a flexible section to which the waistband and pad structure is attached, thereby providing flexibility to accommodate hip movement of the wearer. Separate back and lumbar pads are strapped to the support members. The separate plastic support members may be removed from one pair of contoured side rails and fastened to a pair of side rails of different length to accommodate wearers of different heights and proportions.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to backpacks and particularly to backpack structures suitable for carrying substantial loads for extended time periods. Much has been done in the design of backpacks to deal with discomfort on the part of the wearer resulting from pressure points at any of a number of locations. Typical areas of such concentrated loads may be on the shoulders or hips or the back itself may become tired if too much a load has been carried on the shoulders for too long, rather than on the hips. 
     To deal with such problems, manufacturers of backpacks have provided padded shoulder straps, padded waistbands, padded back panels, etc. Typically the back and waistband members have been formed in a single unit. In some cases it has been found that pressure points are actually introduced by the pads themselves since some padded members will tend to wrinkle and bunch up when carried over one&#39;s shoulders or around one&#39;s waist resulting in creating pressure points. 
     It has also been found that when the waistband members are combined with the back panels, there is frequently a lack of flexibility which results in the pack not fitting as well as would be desirable. Most of the above problems have been dealt with in a number of ways by a number of different backpack manufacturers and the result has been that such backpacks have become progressively more complex and more expensive. There is thus a need for a truly comfortable backpack for carrying substantial loads which is significantly less expensive than most of the better backpacks presently available. 
     BRIEF DESCRIPTION OF THE INVENTION 
     Applicant has, in early models of backpacks, dealt with a number of the potential areas of discomfort by forming padded areas of the backpack with polyfoam pads, some of which are spaced from each other and having a cover of stretch synthetic fabric molded to the pads such that the pads stay in place and do not bunch up, thereby eliminating wrinkling because excess material is dealt with by means of the stretch fabric being molded into the spaces between the pads. Also, by arranging the backpack as a group of modular units, flexibility is enhanced providing superior fit to the wearer. 
     Many older types of backpacks have used an aluminum frame to which are attached carry bags and various shoulder straps, waist belts, etc. Applicant has provided a backpack using aluminum side rails to which are fastened a number of molded plastic frame members each including fixtures for attaching them to the aluminum side rails. Each of these molded plastic members consists of a significant number of truss structures which are designed with variable wall thicknesses and wall depths to provide strength and stiffness where needed and flexibility where needed. Several padded members and support straps are attached to the molded plastic frame members and the truss structures are designed to provide openings located as required to attach the various pad and strap members and also to be significantly strong at the location of such openings so that the strap members and pads are held securely on the frame members when the backpack is heavily loaded. 
     The upper frame member is attached to the tops of the aluminum side rails and includes a pair of socket members. Carried in the top of the separate carry bag is a U-shaped aluminum frame which slides into the sockets and thereby carries most of the weight of the carry bag. The upper molded plastic frame member also includes a number of slots for receiving large buckles attached to the shoulder straps which are fed through the slots to secure the shoulder straps to the frame member. This upper frame member also includes an additional pair of fasteners fastening the member to the side rails at a distance below the top of the rails. 
     Mounted further downwardly on the side rails is a center or second molded plastic frame member. Suspended below the upper part of this member is a relatively flexible &#34;beaver tail&#34; portion. Separate waistband pads are attached to this waist support member which also carries belt and buckle members for fastening the waist band around the waist of the wearer. 
     The bottom plastic frame member supports a U-shaped support member extending rearwardly where it can be utilized to function as a stand for the backpack and to support a bed roll or other items which the wearer may decide to carry at a location below the carry bag. 
     A separate backpad member is present. A separate polyfoam lumbar pad is strapped to the center member and also near the bottom of the &#34;beaver tail&#34; portion such that the lumbar pad is also permitted to move somewhat with this flexible portion. 
     The following features are all present in the improved backpack: 
     1. The pack may be changed in size for different wearers merely by changing the side rails to rails of different length; 
     2. The dual mode flexible &#34;beaver tail&#34; portion of the center plastic support member flexibly supports the waist support member; and 
     3. The design and balance of the frame whereby the bottom plastic frame member acts as a stable platform to rest the pack, when loaded. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This invention may be more clearly understood with the following detailed description and by reference to the drawings in which: 
     FIG. 1 is a perspective view of the backpack of the invention; 
     FIG. 2 is a perspective view of the backpack of the invention as viewed from the rear and with the carry bag exploded away from the frame; 
     FIG. 3 is an exploded view of the backpack of FIG. 1 as viewed from the front; 
     FIG. 4 is a perspective view of the waist support member incorporated in the backpack of FIG. 1; 
     FIG. 5 is a fragmentary side view of the backpack of the invention; 
     FIG. 6 is a perspective rear view of a wearer carrying the backpack of FIG. 1; and 
     FIG. 7 is a perspective front view of a wearer carrying the backpack of FIG. 1. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIG. 1, my backpack 10 includes a carry bag 12 fastened to a frame consisting of a pair of contoured aluminum side rails 14 and 16 to which are attached a plurality of separate molded plastic frame members including a upper member 18, a center member 22 and a bottom or lower member 24 which is fastened to the bottom of rails 14 and 16. The upper frame member 18 includes one pair of fasteners which attach to the tops of the aluminum side rails 14 and 16 and at the back of these fastener structures are a pair of socket members. Fastened to the front side of the upper frame member 18 are shoulder straps 26 and 28 which carry a pair of load control panels (discussed below) to which are secured stabilizing straps 30 and 32 respectively. Also fastened to the front of frame member 18 is a backpad member 34 which is secured at its lower edge to frame member 22. Also attached to frame member 22 is a waist support member 35 which carries padded waist band members 36 and 38. Also fastened to waist support member 35 are web belt members 40 and 42 which fasten together in front of the wearer by means of a buckle 43. 
     FIG. 2 shows a perspective view from the rear of the backpack structure including rails 14 and 16 and the separate molded plastic frame members 18, 22 and 24, with the carry bag 12 exploded away. Upper frame member 18 includes fastening means in the form of clamp members 44 and 46 each of which have molded thereon a socket designed to receive the ends of a U-shaped support member 48 which slips into sockets 44 and 46 and which includes a spring loaded fastener for securing member 48 to sockets 44 and 46. The carry bag 12 also has a number of hook and pile fabric strips arranged along vertical side seams which strips wrap around the aluminum side rails 14 and 16 to secure the carry bag 12 to the rails 14 and 16. It also includes a number of smaller openings for receiving smaller buckles to anchor stabilizing straps 30 and 32 attached to the shoulder straps 26 and 28. U-shaped member 48 is contained in a pocket formed in the top of carry bag 12 such that it carries a substantial part of the weight of carry bag 12. Attached to vertical side seams of carry bag 12 are a plurality of open strips of hook and pile fabric 50 which are wrapped around the contoured rails 14, 16 and fastened together to secure the carry bag to the rails. 
     Mounted further downwardly on the side rails 14 and 16 is a center or second molded plastic frame member 22 which includes two sets of spaced fastening fixtures with a large number of truss members there-between rendering the upper part of this member quite stiff. 
     The lower molded plastic frame member 24 includes sockets 52, 54 into which the lower ends of rails 14 and 16 are inserted. Member 24 includes a U-shaped support member portion for supporting part of the load carried on the backpack and includes slots 56, 58 for locating a pair of straps 60, 62. This U-shaped portion is designed to extend to the rear sufficiently far to constitute a stable platform for supporting the backpack on a reasonably flat surface when the carry bag 12 is loaded. 
     Also shown in FIG. 2 are backpad 34 which is secured to slots near the lower end of frame member 18 and to other slots near the upper end of frame member 22 by means of a pair of straps 64, 66. Shoulder pad 28 is visible in this view and it is fastened to frame member 18 by means of a buckle 68 inserted through a slot in member 18. A similar buckle 70 fastens shoulder strap 26 to frame member 18. 
     FIG. 3 is an exploded view of the backpack according to the invention as seen from the front showing rails 14 and 16 and molded plastic frame members 18, 22, and 24. The center frame member 22 is fastened to the rails 14 and 16 by means of four fastening fixtures 72, 74, 76, and 78. The portion of frame member 22 extending between mounting structures 72, 76 and 74, 78 includes a number of deep triangular and other trusses such that the upper portion of frame member 22 is, although lightweight, very stiff and rugged. Extending downwardly and towards the rear from the upper part of frame member 22 is a thinner, more flexible &#34;beaver tail&#34; portion 80. This portion of frame member 22 will permit some movement both forward and backward but also in a rotating or twisting mode enabling this portion to move with the hips of the wearer. Fastened to this flexible lower portion 80 is the waist support member 35 which, as is more clearly seen in FIG. 4, is an elongated curved member of semi-rigid plastic which includes a plurality of fasteners such as screws 82 which are fastened to mating fasteners in the &#34;beaver tail&#34; portion 80 of member 22. Also fastened to member 35 are a pair of snap fasteners 84 which provide means for attaching the waist pad members 36 and 38. In FIG. 4, member 38 has not been shown in order to delineate the mounting means for the web belt member 42 which is secured to one arm of member 35 and is anchored through slots 86, 87. Web belt member 40 is similarly anchored to the arm on the left side of waist support member 35. With this arrangement the entire waistband structure is mounted somewhat flexibly with respect to the remainder of the backpack frame and is enabled to move with the wearer&#39;s hips. 
     Backpad member 34 includes straps 64 and 66 which pass through slots at the upper edge of frame member 22 and near the lower portion of frame member 18 and the straps are then buckled at the rear side of the backpack as shown in FIG. 2. 
     Member 92 is a lumbar pad which overlies the center portion of waist support member 35 and which includes a plurality of straps 94 having buckle fasteners for fastening itself to frame member 22. Since the lower portion of straps 94 are fastened to the flexible &#34;beaver tail&#34; portion 80 of frame member 22 it will be recognized that the lumbar pad 92 will also move flexibly along with the waist support member 35 with the hip action of the wearer. 
     Shoulder straps 26 and 28 include a polyfoam padded section on the rear side not visible on this view and on the side facing the reader includes a surface of pile material which mates with hook fastening material on a pair of load control panels 96, 98 which are removably secured to the shoulder pads 26, 28. Fastened to the load control panels 96 and 98 are stabilizing straps 30 and 32 which carry buckles for attaching them to ports near the top of frame member 18 as shown. Shoulder straps 26 and 28 also include buckles 68 and 70 which are fastened to any of several pairs of vertically arranged ports or slots 100 or 102 formed as part of frame member 18. These slots are located significantly below the point of attachment to frame member 18 of stabilizing straps 30, 32. Stitched to the load control panels 96, 98 and to the lower ends of shoulder pads 26, 28 are lower stabilizing straps 106, 108 which also fasten to the pair of forwardly extending flanges 110, 112 forming parts of the lower frame member 24. 
     Also attached to flanges 110 and 112 are some relatively short adjustable straps 114, 116 which are secured to waist support member 35. This structure is more clearly shown in FIG. 5 which shows a fragmentary portion of rail 14, the lower frame member 24 including the forwardly extending flange 110 to which is attached the lower stabilizing strap 106, and strap 114 which is attached to waist support member 35. An essentially identical structure to that shown in FIG. 5 would be visible from the opposite side of the backpack wherein all of the members 108, 116, rail 16, and socket 54 with flange 112 would be shown as a mirror image of FIG. 5. 
     FIG. 6 is a perspective rear view of a wearer carrying the backpack of the invention. Shown in this view are side rail 14, to which is attached the lower frame member 24 by means of socket 54. Socket 54 includes the forwardly extending flanges 112 to which straps 116 and 108 are fastened. Fastened to the rear of member 24 are straps 60 and 62 which are shown employed in securing a bedroll member 118 to the backpack below the carry bag 12. Also shown in this view is the shoulder strap 28 carrying load control panel 98 to which is attached the stabilizing strap 32. Strap 32 is attached high on frame member 18, as set forth above. 
     FIG. 7 is a perspective view of the wearer carrying the backpack of the invention as seen from a three quarter front view. The waist support member 35 is shown to which is attached the waist pad 36, the web belt member 40 and the short strap 114 which is attached to the flanges 110 formed on socket 52 of frame member 24. Also shown are shoulder strap 26, the load control panel 96 and attached between load control panel 96 and 98 is a sternum strap 104 which prevents the shoulder straps from spreading too far outwardly. Attached to load control panel 96 is the upper stabilizing strap 30. The bed roll 118 is shown supported below carry bag 12 and above carry bag 12 is a sleeping bag 120 secured by means straps 122 and 124 (FIG. 6) fastened to the upper part of frame member 18. 
     From the foregoing it will be recognized that applicant has provided a backpack design having a considerable number of advantages. This pack is essentially as comfortable as the most elaborate backpacks available yet it is substantially less expensive to manufacture. It is convenient to provide this backpack in different sizes because the molded plastic frame members remain the same and it is only necessary to provide somewhat different length side rails for shorter or taller wearers and the molded frame members can be fastened to any such side rails. With the lower or bottom plastic frame member designed as shown, the backpack will stand on any reasonably flat surface with any normal loading. 
     The above-described embodiments of the present invention are merely descriptive of its principles and are not to be considered limiting. The scope of the present invention instead shall be determined from the scope of the following claims including their equivalents.