Quick reciprocating wrench

A quick reciprocating wrench, comprising:

• a main body comprising a concavely-shaped first jaw opening, the first jaw opening comprising a pivot end on one side and a block portion on another side opposite to the pivot end, the block portion comprising a block face, a first inclination angle being formed by the block face and a first force bearing face of a fastener;
• a claw comprising a concavely-shaped second jaw opening, the second jaw opening comprising a pivotal combination portion on one side and a retaining portion on another side opposite to the pivotal combination portion, the pivotal combination portion of the claw being pivotally connected with the pivot end of the main body along a pivot center, such that the claw and the main body pivotally move with respect to each other, wherein the retaining portion comprises an outer retaining face, a second inclination angle is formed by the outer retaining face and the first force bearing face of the fastener, and the second inclination angle is smaller than the first inclination angle;
• and
• an elastic device disposed between the main body and the claw;
• wherein when the wrench is not engaged with a fastener, the first jaw opening of the main body and the second jaw opening of the claw form a sealing status;
• wherein when the wrench is engaged with the fastener, the fastener is placed in the first jaw opening and the second jaw opening;
• a distance between the block portion and a neighboring first force bearing face of the fastener decreases in a direction in opposite to an expansion direction of the claw with respect to the block portion a largest width of a distal end of the retaining portion is greater than a smallest distance between the block portion and the neighboring first force bearing face of the fastener, and the block face and the first force bearing face of the fastener form a block effect with the retaining portion so as to prevent the retaining portion from detaching with respect to the block portion.