Positioning mechanism for a transducer in a multitrack magnetic tape apparatus or the like

Claim 1

An apparatus for data transfer with a record medium having a plurality of parallel tracks on which data may be recorded, comprising: (a) fixed support means; (b) guide means on the fixed support means extending transversely of the tracks on the record medium; (c) a transducer movable linearly along the guide means with respect to the fixed support means for accessing the individual tracks on the record medium; (d) a stepper motor capable of bidirectional rotation in discrete steps; (e) motion translating means for translating the bidirectional rotation of the stepper motor into the linear travel of the transducer back and forth across the tracks on the record medium; (f) an abutment formed in fixed relation to the transducer for joint movement therewith relative to the fixed support means; (g) a rotary stop member mounted on the fixed support means for rotation about an axis parallel to the guide means; (h) positive drive means for imparting the rotation of the stepper motor to the rotary stop member, the positive drive means being effective to arrest the rotation of the stepper motor when the stop member is locked against rotation; and (i) a stop arm protruding from the rotary stop member for revolution therewith into and out of engagement with the abutment, the angular and axial positions of the stop arm on the stop member being so determined with respect to the linearly variable position of the abutment that the stop arm moves into engagement with the abutment, with the consequent locking of the stop member and therefore of the stepper motor against rotation in a predetermined direction, only when the transducer is moved into alignment with a limit position on the record medium by the rotation of the stepper motor in the predetermined direction, the limit position on the record medium being predetermined in relation to the tracks thereon in order to enable the transducer to access the individual tracks.

Claim 2

An apparatus for data transfer with a record medium having a plurality of parallel tracks on which data may be recorded, comprising: (a) fixed support means; (b) guide means on the fixed support means extending transversely of the tracks on the record medium; (c) a transducer movable linearly along the guide means with respect to the fixed support means for accessing the individual tracks on the record medium; (d) a stepper motor capable of bidirectional rotation in discrete steps; (e) motion translating means for translating the bidirectional rotation of the stepper motor into the linear travel of the transducer back and forth across the tracks on the record medium; (f) an abutment formed in fixed relation to the transducer for joint movement therewith relative to the fixed support means; (g) a rotary stop member mounted on the fixed support means for rotation about an axis parallel to the guide means; (h) positive drive means for imparting the rotation of the stepper motor to the rotary stop member, the positive drive means being effective to arrest the rotation of the stepper motor when the stop member is locked against rotation; and (i) a stop arm protruding from the rotary stop member for revolution therewith into and out of engagement with the abutment, the angular and axial positions of the stop arm on the stop member being so determined with respect to the linearly variable position of the abutment that the stop arm moves into engagement with the abutment, with the consequent locking of the stop member and therefore of the stepper motor against rotation in a predetermined direction, only when the transducer is moved into alignment with a limit position on the record medium by the rotation of the stepper motor in the predetermined direction, the limit position on the record medium being predetermined in relation to the tracks thereon in order to enable the transducer to access the individual tracks.

Claim 9

An apparatus for data transfer with a record medium having a plurality of parallel tracks on which data may be recorded, the tracks being disposed between first and second preassigned limit positions on the record medium, the apparatus comprising: (a) fixed support means; (b) guide means on the fixed support means extending transversely of the tracks on the record medium; (c) a transaducer guided by the guide means for moving between the first and second limit positions on the record medium in order to access the individual tracks on the record medium; (d) a stepper motor capable of bidirectional rotation in discrete steps; (e) motion translating means for translating the bidirectional rotation of the stepper motor into the linear travel of the transducer back and forth across the tracks on the record medium; (f) an abutment formed in fixed relation to the transducer for joint movement therewith relative to the fixed support means; (g) a rotary stop member mounted on the fixed support means for rotation about an axis parallel to the guide means, the rotary stop member being positively driven by the stepper motor and being effective, when locked against rotation in either direction, to arrest the rotation of the stepper motor in the corresponding direction; (h) a first stop arm protruding from the rotary stop member for revolution therewith into and out of engagement with the abutment, the first stop arm moving into engagement with the abutment when the transducer is moved into alignment with the first limit position on the record medium, with the result that the transducer is prevented from traveling past the first limit position in a direction away from the second limit position; and (i) a second stop arm protruding from the rotary stop member for revolution therewith into and out of engagement with the abutment, the second stop arm moving into engagement with the abutment when the transducer is moved into alignment with the second limit position on the record medium, with the result that the transducer is prevented from traveling past the second limit position in a direction away from the first limit position.

Claim 10

An apparatus for data transfer with a record medium having a plurality of parallel tracks on which data may be recorded, the tracks being disposed between first and second preassigned limit positions on the record medium, the apparatus comprising: (a) fixed support means; (b) guide means on the fixed support means extending transversely of the tracks on the record medium; (c) a transaducer guided by the guide means for moving between the first and second limit positions on the record medium in order to access the individual tracks on the record medium; (d) a stepper motor capable of bidirectional rotation in discrete steps; (e) motion translating means for translating the bidirectional rotation of the stepper motor into the linear travel of the transducer back and forth across the tracks on the record medium; (f) an abutment formed in fixed relation to the transducer for joint movement therewith relative to the fixed support means; (g) a rotary stop member mounted on the fixed support means for rotation about an axis parallel to the guide means, the rotary stop member being positively driven by the stepper motor and being effective, when locked against rotation in either direction, to arrest the rotation of the stepper motor in the corresponding direction; (h) a first stop arm protruding from the rotary stop member for revolution therewith into and out of engagement with the abutment, the first stop arm moving into engagement with the abutment when the transducer is moved into alignment with the first limit position on the record medium, with the result that the transducer is prevented from traveling past the first limit position in a direction away from the second limit position; and (i) a second stop arm protruding from the rotary stop member for revolution therewith into and out of engagement with the abutment, the second stop arm moving into engagement with the abutment when the transducer is moved into alignment with the second limit position on the record medium, with the result that the transducer is prevented from traveling past the second limit position in a direction away from the first limit position.

Claim 13

An apparatus for data transfer with a record medium having a plurality of parallel tracks on which data may be recorded, the tracks including a home track and being all disposed between first and second preassigned limit positions on the record medium, the first and second limit positions being spaced a known distance away from each other, with the first limit position disposed a known distance away from the home track, the apparatus comprising: (a) fixed support means; (b) guide means on the fixed support means extending transversely of the tracks on the record medium; (c) a transducer guided by the guide means for moving between the first and second limit positions on the record medium in order to access the individual tracks on the record medium, the transducer being initialized on the home track on the record medium; (d) a stepper motor having a plurality of phase windings to be excited individually for bidirectional rotation in discrete steps, each step of the stepper motor being defined as the excitation of one phase winding thereof, the phase windings of the stepper motor including a predetermined one which is to be excited when the transducer is aligned with the first limit position on the record medium; (e) motion translating means for translating the bidirectional rotation of the stepper motor into the linear travel of the transducer back and forth across the tracks on the record medium; (f) an abutment formed in fixed relation to the transducer for joint movement therewith relative to the fixed support means; (g) a rotary stop member mounted on the fixed support means for rotation about an axis parallel to the guide means, the rotary stop member being positively driven by the stepper motor and being effective, when locked against rotation in either direction, to arrest the rotation of the stepper motor in the corresponding direction; (h) a first stop arm protruding from the rotary stop member for revolution therewith into and out of engagement with the abutment, the first stop arm moving into engagement with the abutment when the transducer is moved into alignment with the first limit position on the record medium upon excitation of the predetermined phase winding of the stepper motor, with the result that the transducer is prevented from traveling beyond the first limit position in a direction away from the second limit position despite the continued energization of the stepper motor; (i) a second stop arm protruding from the rotary stop member for revolution therewith into and out of engagement with the abutment, the second stop arm moving into engagement with the abutment when the transducer is moved into alignment with the second limit position on the record medium, with the result that the transducer is prevented from traveling beyond the second limit position in a direction away from the first limit position; and (j) control means effective for initializing the position of the transducer on the home track on the record medium by: (1) exciting the phase windings of the stepper motor a first preselected number of steps in a first prescribed sequence for moving the transducer to the first limit position on the record medium, the first preselected number of steps being greater than a known number of steps of the stepper motor required for moving the transducer the full distance from the second to the first limit position on the record medium; (2) further exciting, if the predetermined phase winding of the stepper motor is not being excited upon completion of the excitation of the stepper motor the first preselected number of steps, the phase windings of the stepper motor in the first prescribed sequence until the predetermined phase winding becomes excited; and (3) further exciting in a second prescribed sequence, opposite to the first prescribed sequence, the phase windings of the stepper motor a second preselected number of steps required for moving the transducer from the first limit position to the home track on the record medium.

Claim 14

An apparatus for data transfer with a record medium having a plurality of parallel tracks on which data may be recorded, the tracks including a home track and being all disposed between first and second preassigned limit positions on the record medium, the first and second limit positions being spaced a known distance away from each other, with the first limit position disposed a known distance away from the home track, the apparatus comprising: (a) fixed support means; (b) guide means on the fixed support means extending transversely of the tracks on the record medium; (c) a transducer guided by the guide means for moving between the first and second limit positions on the record medium in order to access the individual tracks on the record medium, the transducer being initialized on the home track on the record medium; (d) a stepper motor having a plurality of phase windings to be excited individually for bidirectional rotation in discrete steps, each step of the stepper motor being defined as the excitation of one phase winding thereof, the phase windings of the stepper motor including a predetermined one which is to be excited when the transducer is aligned with the first limit position on the record medium; (e) motion translating means for translating the bidirectional rotation of the stepper motor into the linear travel of the transducer back and forth across the tracks on the record medium; (f) an abutment formed in fixed relation to the transducer for joint movement therewith relative to the fixed support means; (g) a rotary stop member mounted on the fixed support means for rotation about an axis parallel to the guide means, the rotary stop member being positively driven by the stepper motor and being effective, when locked against rotation in either direction, to arrest the rotation of the stepper motor in the corresponding direction; (h) a first stop arm protruding from the rotary stop member for revolution therewith into and out of engagement with the abutment, the first stop arm moving into engagement with the abutment when the transducer is moved into alignment with the first limit position on the record medium upon excitation of the predetermined phase winding of the stepper motor, with the result that the transducer is prevented from traveling beyond the first limit position in a direction away from the second limit position despite the continued energization of the stepper motor; (i) a second stop arm protruding from the rotary stop member for revolution therewith into and out of engagement with the abutment, the second stop arm moving into engagement with the abutment when the transducer is moved into alignment with the second limit position on the record medium, with the result that the transducer is prevented from traveling beyond the second limit position in a direction away from the first limit position; and (j) control means effective for initializing the position of the transducer on the home track on the record medium by: (1) exciting the phase windings of the stepper motor a first preselected number of steps in a first prescribed sequence for moving the transducer to the first limit position on the record medium, the first preselected number of steps being greater than a known number of steps of the stepper motor required for moving the transducer the full distance from the second to the first limit position on the record medium; (2) further exciting, if the predetermined phase winding of the stepper motor is not being excited upon completion of the excitation of the stepper motor the first preselected number of steps, the phase windings of the stepper motor in the first prescribed sequence until the predetermined phase winding becomes excited; and (3) further exciting in a second prescribed sequence, opposite to the first prescribed sequence, the phase windings of the stepper motor a second preselected number of steps required for moving the transducer from the first limit position to the home track on the record medium.