Backpack

Abstract

A backpack includes a bag body, two straps, and a back casing. The straps are engaged with the bag body. The bag body has an inner surface and an outer surface opposite to the inner surface. The inner surface is adapted to face a user's body. The back casing is detachably engaged with the bag body and is located outside of the outer surface. When the back casing is engaged with the bag body, the backpack could protect the bag body and a user's back. The back casing could be detached from the bag body when the back casing is not needed, providing a more flexible way for the user to use it.

1 . A backpack, comprising:
 a bag body having an inner surface and an outer surface opposite to the inner surface, wherein the inner surface is adapted to face a user's body, and at least one fixing strap is connected to the bag body;   two straps engaged with the bag body; and   a back casing having two opposite side edges, at least two notches, and at least two perforations, wherein each of the at least two notches is located between one of the side edges and one of the at least two perforations, and communicates with one of the at least two perforations and an outside of the corresponding side edge; the at least two perforations are adapted to be penetrated through by the at least one fixing strap from the corresponding notch, thereby the back casing is able to be detachably engaged with the bag body and located outside of the outer surface.   
     
     
         2 . The backpack of  claim 1 , wherein the at least one fixing strap comprises a first section and a second section; the first section and the second section are respectively connected to two opposite sides of the bag body; the first section and the second section are detachably connected. 
     
     
         3 . The backpack of  claim 2 , wherein the first section is connected to a first engaging member, and the second section is connected to a second engaging member; the first engaging member and the second engaging member are detachably engaged with each other; the first section is detachably engaged with the second section via the first engaging member and the second engaging member. 
     
     
         4 . (canceled) 
     
     
         5 . The backpack of  claim 1 , wherein each of the at least two perforations is elongated, and each of the at least two notches is located between two ends of the corresponding perforation. 
     
     
         6 . (canceled) 
     
     
         7 . The backpack of  claim 1 , wherein the back casing sequentially has an upper section, a middle section, and a lower section from top down; the upper section corresponds to a top portion of the bag body; the lower section corresponds to a bottom portion of the bag body; the upper section and the lower section respectively incline in a direction from the middle section toward the outer surface of the bag body. 
     
     
         8 . The backpack of  claim 1 , wherein the back casing has two lateral portions and a middle portion located between the lateral portions; each of the at least two notches and each of the at least two perforations are located on one of the two lateral portions; the middle portion has a receiving groove facing the outer surface of the bag body; the two lateral portions are thicker than a rest portion of the back casing. 
     
     
         9 . The backpack of  claim 1 , wherein the back casing has at least one opening penetrating through the inner surface and the outer surface of the back casing. 
     
     
         10 . The backpack of  claim 1 , wherein the bag body is connected to a first engaging member and a second engaging member, and the back casing is connected to a third engaging member and a fourth engaging member; the first engaging member is detachably engaged with the third engaging member; the second engaging member is detachably engaged with the fourth engaging member. 
     
     
         11 . The backpack of  claim 1 , wherein the back casing has a recess facing the outer surface of the bag body. 
     
     
         12 . A backpack, comprising:
 a bag body having an inner surface and an outer surface opposite to the inner surface, wherein the inner surface is adapted to face a user's body;   two straps engaged with the bag body; and   a back casing detachably engaged with the bag body and located outside of the outer surface;   wherein the back casing has an inner surface facing the outer surface of the bag body; a felt layer is disposed on the inner surface and is adapted to be detachably attached by at least one object provided with a corresponding fastener.   
     
     
         13 . A backpack, comprising:
 a bag body having an inner surface and an outer surface opposite to the inner surface, wherein the inner surface is adapted to face a user's body, and at least one fixing strap is connected to the bag body;   two straps engaged with the bag body; and   a back casing having two opposite side edges, at least two notches, and at least two perforations, wherein each of the at least two notches is located between one of the side edges and one of the at least two perforations, and communicates with one of the at least two perforations and an outside of the corresponding side edge; the at least two perforations are adapted to be penetrated through by the at least one fixing strap from the corresponding notch, thereby the back casing is able to be detachably engaged with the bag body and located outside of the outer surface;   wherein the back casing has an inner surface facing the outer surface of the bag body; a felt layer is disposed on the inner surface and is adapted to be detachably attached by at least one object provided with a corresponding fastener.