Patent ID: 6976411

Claim:
An extension tool comprising: a shaft including a bore formed therein and having a non-circular cross section, and including a front portion having a reduced outer diameter to form a peripheral shoulder in said front portion thereof, and including an annular groove and an orifice and an aperture formed in said front portion thereof, a retaining ring and a ball engaged into and received in said annular groove and said orifice of said shaft respectively, a stem slidably engaged into said bore of said shaft and extendible out of said shaft, and including a plurality of depressions formed therein, for selectively receiving said ball, and for adjustably securing said stem to said shaft, said stem including a non-circular cross section corresponding to that of said bore of said shaft, to prevent said stem from being rotated relative to said shaft, a control ferrule slidably engaged onto said front portion of said shaft, and including a peripheral protrusion extended radially and inwardly therefrom, for engaging with said ball, and for forcing said ball to engage into either of said depressions of said stem, and thus for adjustably locking said stem to said shaft, said control ferrule including a front portion engageable with said retaining ring, to limit said control ferrule to slide relative to said shaft, and to prevent said control ferrule from being disengaged from said shaft, a spring member engaged onto said front portion of said shaft, and engaged between said peripheral protrusion and said peripheral shoulder of said shaft, to force said peripheral protrusion to engage with said ball, and a spring-biased projection attached to a rear portion of said stem, and having a spring-biased detent movable out of said stem to selectively engage into said aperture of said shaft, in order to lock said stem to said shaft, and to prevent said stem from being disengaged from said shaft inadvertently.