Patent ID: 6029551
Filing Date: 2000-02-29
Classification: B25B

Abstract:
A screwdriver comprising:a handle provided with an axial hole;a first magnetic member fixed in said axial hole of said handle;a shank rotatable disposed in said axial hole and provided at a first end thereof with a blade fastened therewith, said shank having a second end attractive to said first magnetic member, said shank capable of turning in relation to said handle at such time when the screwdriver is exerted on by a torsional moment greater than a pre-set torsional moment of the screwdriver; andan adjusting device for adjusting the magnitude of attractive force between said first magnetic member and said second end of said shank, so as to determine said pre-set torsional moment of the screwdriver;wherein said second end of said shank is provided with a second magnetic member fastened therewith; and wherein either said first magnetic member or said second magnetic member is a magnet;wherein said adjusting device comprises:a tubular member provided in an outer periphery thereof with a threaded portion which is engaged with said axial hole of said handle a first end of said tubular member being in contact with said second magnetic member; anda ring fastened with said shank such that said ring is in contact with a second end of said tubular member;said first magnetic member and said second magnetic member being spaced apart by a distance which can be adjusted by adjusting a depth in which said tubular member is engaged in said axial hole.