Backpack frame

Abstract

A backpack includes an upper cross member having a first end and a second end, and a lower cross member offset vertically from the upper cross member and having a third end and a fourth end. The frame includes a first rail connected to the upper cross member at the first end and the lower cross member inwards of the third end, and a second rail fixed to the upper cross member inwards from the first end and the lower cross member at the third end.

What is claimed is: 
     
         1 . A backpack, comprising:
 a shoulder strap assembly including a right shoulder strap and a left shoulder strap;   a hip belt; and   a frame, the frame including:   an upper cross member having a first end and a second end and wherein the shoulder strap assembly is coupled to the upper cross member,   a lower cross member offset vertically from the upper cross member and having a third end and a fourth end,   a first rail set having a first rail and a second rail, the first rail being fixed to the upper cross member at the first end and the lower cross member inwards of the third end, the second rail fixed to the upper cross member inwards from the first end and the lower cross member at the third end, and the first rail and second rail abut along a portion vertically between the upper cross member and the lower cross member, and   a second rail set having a third rail and a fourth rail, the third rail being fixed to the upper cross member at the second end and the lower cross member inwards of the fourth end, the fourth rail fixed to the upper cross member inwards from the second end and the lower cross member at the fourth end, and the first rail and second rail abut along a portion vertically between the upper cross member and the lower cross member.   
     
     
         2 . The backpack of  claim 1 , wherein at least one of the first rail, the second rail, the third rail, and the fourth rail is hollow. 
     
     
         3 . The backpack of  claim 2 , wherein a cross-section of the at least one of the first rail, the second rail, the third rail, and the fourth rail is square. 
     
     
         4 . The backpack of  claim 2 , wherein a cross-section of the at least one of the first rail, the second rail, the third rail, and the fourth rail is oval. 
     
     
         5 . The backpack of  claim 1 , wherein at least one of the first rail, the second rail, the third rail, and the fourth rail is solid. 
     
     
         6 . The backpack of  claim 1 , including an extensible member connected to the frame and configured to extend in a vertical direction away from the upper cross member. 
     
     
         7 . The backpack of  claim 1 , including a freight shelf hingedly attached to the frame. 
     
     
         8 . A frame for a backpack, comprising:
 an upper cross member having a first end and a second end;   a lower cross member offset vertically from the upper cross member and having a third end and a fourth end; and   a first rail set having a first rail and a second rail, the first rail being fixed to the upper cross member at the first end and the lower cross member inwards of the third end, the second rail fixed to the upper cross member inwards from the first end and the lower cross member at the third end, and the first rail and second rail abut along a portion vertically between the upper cross member and the lower cross member.   
     
     
         9 . The frame of  claim 8 , further comprising:
 a second rail set having a third rail and a fourth rail, the third rail being fixed to the upper cross member at the second end and the lower cross member inwards of the fourth end, the fourth rail fixed to the upper cross member inwards from the second end and the lower cross member at the fourth end, and the first rail and second rail abut along a portion vertically between the upper cross member and the lower cross member.   
     
     
         10 . The frame of  claim 9 , wherein at least one of the first rail, the second rail, the third rail, and the fourth rail is hollow. 
     
     
         11 . The frame of  claim 10 , wherein a cross-section of the at least one of the first rail, the second rail, the third rail, and the fourth rail is square. 
     
     
         12 . The frame of  claim 10 , wherein a cross-section of the at least one of the first rail, the second rail, the third rail, and the fourth rail is oval. 
     
     
         13 . The frame of  claim 9 , wherein at least one of the first rail, the second rail, the third rail, and the fourth rail is solid. 
     
     
         14 . The frame of  claim 8 , including an extensible member connected to the frame and configured to extend in a vertical direction away from the upper cross member. 
     
     
         15 . The frame of  claim 8 , including a freight shelf hingedly attached to the frame. 
     
     
         16 . A frame for a backpack, comprising:
 an upper cross member having a first end and a second end;   a lower cross member offset vertically from the upper cross member and having a third end and a fourth end;   a first rail connected to the upper cross member at the first end and the lower cross member inwards of the third end; and   a second rail fixed to the upper cross member inwards from the first end and the lower cross member at the third end.   
     
     
         17 . The frame of  claim 16 , further comprising:
 a third rail connected to the upper cross member at the second end and the lower cross member inwards of the fourth end; and   a fourth rail connected to the upper cross member inwards from the second end and the lower cross member at the fourth end.   
     
     
         18 . The frame of  claim 17 , wherein at least one of the first rail, the second rail, the third rail, and the fourth rail is hollow. 
     
     
         19 . The frame of  claim 18 , wherein a cross-section of the at least one of the first rail, the second rail, the third rail, and the fourth rail is square. 
     
     
         20 . The frame of  claim 18 , wherein a cross-section of the at least one of the first rail, the second rail, the third rail, and the fourth rail is oval.