Patent ID: 7328445

Claim:
An apparatus for converting a rotational movement to a linear movement, comprising: a lead screw; a pickup; and a slider having a first protrusion and a second protrusion which are inserted into the groove of said lead screw, wherein said first protrusion is adapted to substantially tightly fit into the groove of said lead screw whereby the rotational movement of said lead screw is converted into the linear movement of said pickup; wherein the second protrusion is adapted to remain in the groove of the lead screw even if the first protrusion is moved out of the thread of said lead screw; and wherein said slider further comprises a first extension portion on which the first protrusion is formed, and a second extension portion on which the second protrusion is formed, the apparatus further comprising a support portion adapted to support the second extension portion such that a designated minimum force is required to separate said second protrusion from the groove of said lead screw.