Hinge

A hinge for connecting two separate apparatuses that rotates around a common axis, comprising:

• a first pair of structures that comprise a first structure and a second structure, an end of said first pair of structures is fixed in a first apparatus;
• a second pair of structures that comprise a third structure and a fourth structure, where an end of said second pair of structures is fixed in a second apparatus, and said second pair of structures locates between said first structure and said second structure, wherein said third structure is adjacent to said first structure and said fourth structure is adjacent to said second structure, said second pair of structures is directly coupled with said first pair of structures by a hook which locates on said fourth structure and are used to hook said second structure;
• a torsional spring, an end of said torsional spring is fixed in said first structure, said second structure or said first apparatus, another end of said torsional spring is fixed in said third structure, said fourth structure of said second apparatus.

A hinge for connecting two separate apparatuses that rotates around a common axis, comprising:

• a first pair of structures that comprise a first structure and a second structure, an end of said first pair of structures is fixed in a first apparatus;
• a second pair of structures that comprising a third structure and a fourth structure, where an end of said second pair of structures is fixed in a second apparatus, and said second pair of structures locates between said first structure and said second structure, wherein said third structure is adjacent to said first structure and said fourth structure is adjacent to said second structure, moreover, said first pair of structures is directly coupled with said second pair of structures by a bulge which locates on said first structure and directly contacts with said third structure, besides, said second pair of structures is directly coupled with said first pair of structures by a hook which locates on said fourth structure and are used to hook said second structure;
• a torsional spring, an end of said torsional spring is fixed in said first structure, said second structure or said first apparatus, another end of said torsional spring is fixed in said third structure, said fourth structure of said second apparatus.