Looking slide drive for a disc scanner

An apparatus for inscribing and/or reading a rotating information carrier, comprising

• a frame carrying a turntable for supporting the information carrier, which turntable is rotatable about an axis of rotation,
• a slide which is movable along a path between two end positions and carries a scanning unit,
• a rectilinear guide means for the slide, arranged on the frame,
• a linear motor unit having a stator section fixedly secured to the frame and an armature section fixedly secured to the slide, and
• holding means for retaining the slide in an end position relative to the frame while the apparatus is in an inoperative condition, said holding means comprising a holding device and a control unit,
• characterized in that said holding means is arranged for holding the slide while the apparatus is in an operative condition and the slide is not being moved,
• the holding device comprises an electrically energizable clamping unit which
• a) in the non-energized condition clamps the slide, with the armature section of the linear motor unit fixedly secured thereto, in any arbitrary position of the slide along said path, and
• b) in the energized condition does not clamp the slide and the armature section which is fixedly secured thereto, and
• while said apparatus is in said operative condition said control unit turns on a first energizing current to the motor unit and a second energizing current, separate from said first energizing current, to the clamping unit at the beginning of a displacement of the slide along the guide means, said second energizing current being turned on substantially simultaneously with but just before said first energizing current;
• and said control unit turns off the first energizing current and the second energizing current at the end of the displacement, said second energizing current being turned off substantially simultaneously with said first energizing current.

An apparatus for inscribing and/or reading a rotating information carrier, comprising

• a frame carrying a turntable for supporting the information carrier, which turntable is rotatable about an axis of rotation,
• a slide which is movable along a path between two end positions and carries a scanning unit,
• a rectilinear guide means for the slide, arranged on the frame,
• a linear motor unit having a stator section fixedly secured to the frame and an armature section fixedly secured to the slide, and
• a holding device for retaining the slide in an end position relative to the frame,
• characterized in that the holding device comprises an electrically energizable clamping unit which
• a) comprises a solenoid having a movable actuating element, and secured to the frame;
• a blade spring secured to the frame and cooperating with the actuating element;
• and a strip secured to the slide and extending between the solenoid and the blade spring and parallel to the path of the slide,
• b) in the non-energized condition clamps the slide, with the armature section of the linear motor unit fixedly secured thereto, in any arbitrary position of the slide along said path;
• said strip being clamped between the blade spring and the solenoid or a part of the frame when the solenoid is not energized, and
• c) in the energized condition does not clamp the slide and the armature section which is fixedly secured thereto;
• said strip being clear of the solenoid, the frame and the blade spring when the solenoid is energized, and
• said holding device further comprises a control unit which during operation of the device at least substantially simultaneously turns on a first energizing current to the motor unit and a second energizing current, separate from said first energizing current, to the clamping unit at the beginning of a displacement of the slide along the guide means;
• and which at least substantially simultaneously turns off the first energizing current and the second energizing current at the end of the displacement.