Patent ID: 7318365

Claim:
A multistage socket comprising: a main body having a disc section, at least three fixing blocks being disposed on one face of the disc section at equal angular intervals, two lateral sides of each fixing block being respectively formed with two first cavities extending from outer side toward a center of the disc section, an inner end of each first cavity being formed with a first stop face, the main body further having a coupling section formed on the other face of the disc section; at least three movable blocks each of which is arranged between two adjacent fixing blocks, inner end faces of the movable blocks facing the center of the disc section defining a polygonal hole, outer end face of each movable block being formed with an axially extending arced locating section outward protruding from the outer end face of the movable block, two lateral sides of each movable block being respectively formed with two second cavities adjacent to the two lateral sides of the fixing block, the first cavity of the fixing block and the second cavity of the adjacent movable block communicating with each other, an outer end of each second cavity being formed with a second stop face opposite to the first stop face, the first cavity and the adjacent second cavity together forming a receiving space in which a resilient member is accommodated, two ends of the resilient member respectively abutting against the first and second stop faces; and a rotary member rotatably fitted around the disc section of the main body, the rotary member having a front face formed with a central through hole communicating with the polygonal hole and having an annular wall perpendicularly extending from an outer circumference of the front face, at least three arced guide sections being formed an inner face of the annular wall at intervals, each arced guide section having multiple recessed arced faces, the thickness of the annular wall between the multiple recessed arced faces and the outer circumference of the annular wall being tapered, whereby the locating sections of the movable blocks can abut against the corresponding recessed arced faces of the arced guide sections with the same thickness.