Patent ID: 8156846

Claim:
An extension rod assembly, comprising: a body having a polygonal end at a first end thereof and an engaging end at a second end of the body, an axial passage defined in the first end of the body and a restriction hole defined in one of sides of the polygonal end of the body, the restriction hole communicating with the axial passage, an end piece sealing the axial passage at the first end of the body, a recessed area defined in an outer periphery of the body and a positioning hole defined in the recessed area, the positioning hole communicating with the axial passage; a control member having a handle and a shaft which extends from a side of the handle, the shaft rotatably inserted into the positioning hole and the handle rotatably engaged with the recessed area, the control member being rotatable about an axis thereof, a recess defined radially in the shaft and forming an eccentric part relative to the shaft, the recess located within the axial passage; an operation rod axially and movably inserted into the axial passage from the first end of the body and a spring being biased between a first end of the operation rod and the end piece, the operation rod including a first dent and a second dent which is located adjacent the first dent in axial direction and communicates with the first dent, the second dent being deeper than the first dent in radial direction, the first and second dents being movable to be in alignment with the restriction hole respectively, a second end of the operation rod engaged with the recess in the shaft, and a bead movably engaged with the restriction hole and the second end of the operation rod being driven axially by the eccentric part when rotating the shaft so that the bead partially protrudes out from the restriction hole when the bead is engaged with the first dent, the and the bead being merged into the restriction hole when the bead is engaged with the second dent.