A socket wrench includes vertical groove on its internal wall and a supporting plate having projections corresponding with grooves for securing the plate to the socket. Fix pins covered with spring are slidably inserted on the plate. Nut is locked through the flexible extension of fix pins and spring and the nut and screw can be installed or removed through loop bar with force turning. This invention, with its simple structure and easy operation, is suitable for driving nuts of various sizes.

　　A preferred embodiment of a socket wrench will be described in detail in the accompanying drawings which form a part hereof, and wherein:
FIG. 1 is an exploded view of a socket wrench in accordance with the present invention;
FIG. 2 is a cross-sectional view of the line A-A of FIG 1.
FIG 3 is structure of center pin.
FIG 4 is structure of fix pin.
Referring to the drawings, and initially to FIG. 1 and 2, a socket wrench in accordance with the present invention comprises socket 1, loop bar 7, supporting plate 3, center pin 2, fix pin 4 and spring 5. Socket 1 includes an internal wall of a hexagonal cross section having a vertical groove 8 of each side extended outward from middle of the socket to the top. A supporting plate 3 is installed into the socket 1 and has 6 projections 6 on its peripheral portion corresponding with groove 8, which engaged with the groove for securing the plate 3 to the socket 1. Plate 3 also includes a central hole inside which a center pin 2 of hexagonal top is slidable installed. Set on pin 2 is a spring 5, one end of which is on the hexagonal top of pin 2 and the other on the surface of plate 3. 56 apertures are formed on plate 3 in rule of isometry and equilateral triangle. Each aperture is installed with a fix pin 4 of cylinder top which is covered with spring 5 with one end on cylinder of pin 4 and the other also on the surface of plate 3. FIG. 3 and 4 show the structure of center and fix pins.
One or two vertical grooves 8 can be arranged on each side of the hexagon, or arranged every two sides. In the similar way, the number and position of projections 6 on peripheral portion of plate 3 have to correspond with groove 8.