Patent ID: 6556385
Filing Date: 2003-04-29
Classification: G11B

Abstract:
A head sending mechanism for sending a head assembly up and down along a predetermined axis extending in an up and down direction, said head sending mechanism comprising:a lead screw with an external thread having a rotation axis corresponding to said predetermined axis, a head lift on which said head assembly is mounted, providing a through hole from a lower side to an upper side thereof in the up and down direction for freely receiving said lead screw, and providing a middle space which is open to the outside of said head lift and partly coincides with said through hole at the middle thereof in the up and down direction, a head guide fixed at said lower side of said head lift and having a first internal thread for engaging with said external thread of said lead screw to move said head lift up and down along said predetermined axis according to rotation of said lead screw around said rotation axis, a preload bushing located in said middle space of said head lift so as to be out of contact with said head lift in the up and down direction and not to rotate around said rotation axis, said preload bushing having a second internal thread for engaging with said external thread of said lead screw, a compressed coil spring located between said head lift and said preload bushing in said middle space of said head lift for pressing said head lift against said preload bushing along said predetermined axis to force said preload bushing toward said head guide.