US4098474A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tape drive for a cassette in a sound reproducer and/or recorder
Assignee: Blaupunkt Werke GmbH
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Filing: 1976-12-22
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Granted: 1978-07-04
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Expires: 1996-12-22
Abstract
Abstract An axial-gap flat type motor with an annular permanent magnet and a non-magnetic disk rotor with a printed winding directly drives a coaxial tape capstan and indirectly drives the spindles engaging the supply and take-up reels in the cassette. The capstan and the spindles are shifted in a direction parallel to the motor axis in moving between an idle position and an operating position, the insertion of a cassette being sufficient to cause movement into the operating position. The capstan shaft accordingly is axially displaceable in the motor, shifting within the movable inner portion of a central bearing to which the rotor is affixed. The capstan shaft has radial projections engaging internal grooves in the movable bearing portion and springs urge these projections towards one or the other of their axial end positions in the bearing, corresponding respectively to the idle and operating positions of the capstan. Current is fed to the rotor by spring-pressed studs located in the central bearing and the annular permanent magnet stator. Light passing through slots in the edge of the rotor disk is optoelectrically detected to produce a speed regulating signal to a regulating circuit that controls the voltage of which current is supplied to the motor. The low moment of inertia of the drive makes the speed regulation accurate and facilitates transitions into and out of fast-forward and fast-rewind modes. The printed windings on the rotor produce smooth motion in response to direct current excitation.
Inventors
- 👤 Fritz Lehnert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:42
CPC Classifications
G; G11; G11B; G11B15/00; G11B15/18
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
182 words
Tape drive for a magnetic tape cassette record and/or player having both steady speed and low inertia, as well as small axial dimensions, comprising in combination: a direct current motor of the axial air-gap type having an annular multipolar permanent magnet stator and a substantially disc shaped rotor of non-magnetic material and a shaft concentric with and driven by said rotor having an extension disposed and shaped as a tape transport capstan; means, including take-up and pay-out spindles for insertion in a cassette and a pressure roller facing said capstan, for driving of tape contained in the cassette past at least one magnetic transducer head at a rate determined by the rotation rate of said shaft, all the movable portions of said motor, shaft, and driving means having low moment of inertia, and means, including features at or near the periphery of said rotor and non-rotary elements fixed in said motor at locations suitable for cooperation with said features of said rotor, for generating an electric signal of a frequency proportional to motor speed for use by a motor speed regulating circuit.
Claim 2
Dependent Claim
182 words
Tape drive for a magnetic tape cassette record and/or player having both steady speed and low inertia, as well as small axial dimensions, comprising in combination: a direct current motor of the axial air-gap type having an annular multipolar permanent magnet stator and a substantially disc shaped rotor of non-magnetic material and a shaft concentric with and driven by said rotor having an extension disposed and shaped as a tape transport capstan; means, including take-up and pay-out spindles for insertion in a cassette and a pressure roller facing said capstan, for driving of tape contained in the cassette past at least one magnetic transducer head at a rate determined by the rotation rate of said shaft, all the movable portions of said motor, shaft, and driving means having low moment of inertia, and means, including features at or near the periphery of said rotor and non-rotary elements fixed in said motor at locations suitable for cooperation with said features of said rotor, for generating an electric signal of a frequency proportional to motor speed for use by a motor speed regulating circuit.
Claim 3
Dependent Claim
39 words
A tape drive as defined in claim 1, in which said driving means includes a friction wheel drive connection and a slip coupling for driving one of said spindles as a take-up spindle by the force of said motor.
Claim 4
Dependent Claim
41 words
A tepe drive as defined in claim 1, in which said driving means includes at least one drive belt (22) and a slip coupling for driving one of said spindles as a take-up spindle (3) by the force of said motor.
Claim 5
Dependent Claim
151 words
A tape drive as defined in claim 1, which also comprises means for reversing the polarity of the current supplied to said motor and in which said driving means comprises a slip coupling for driving one of said spindles as a take-up spindle (3) by the force of said motor and also an idler wheel (5) having a laterally shiftable axle and in which there are also provided means for shifting the axle of said idler wheel in response to the placing of the tape drive in the fast rewind mode upon operation of said means for reversing supply current polarity, to engage wheels (3a,4a) or rollers respectively affixed to said spindles (3,4) for transfer of rotary motion force between said spindles and for shifting the axle of said idler wheel (5) to disengage the idler wheel in response to the tape drive being taken out of the fast rewind condition.
Claim 6
Dependent Claim
40 words
A tape drive as defined in claim 1, in which the drive motor (1) is mounted on a chassis (20) a portion of which serves as the bottom plate for the motor casing and is made of magnetically conducting material.
Claim 7
Dependent Claim
30 words
A tape drive as defined in claim 1, in which said disk shaped rotor (11) is constituted of a least one thin insulating plate on which conducting paths are printed.
Claim 8
Dependent Claim
46 words
A tape drive as defined in claim 6, in which said conducting paths run radially in the annular portion of said disk which is within the same radial distance range from the motor axis as the annular permanent magnet serving as the stator of the motor.
Claim 9
Dependent Claim
37 words
A tape drive as defined in claim 7, in which, in the space enclosed by the said annular permanent magnet (10), resiliently urged contact members are provided which ride on respective contact areas of said rotor (11).
Claim 10
Dependent Claim
87 words
A combination of a tape drive as defined in claim 1, with electronic speed regulating means (25) having an input connected to one of said elements in said motor for generating an electric signal of a frequency proportional to motor speed so as to receive said signal, said speed regulating means being constituted to operate in response to said electric signal to control the voltage at which current is supplied to the rotor of the motor in such a way as to maintain the rotor speed constant.
Claim 11
Dependent Claim
60 words
A tape drive as defined in claim 1, in which said non-rotary elements fixed in said motor for cooperation with features at or near the periphery of said rotor for generating an electric signal of a frequency proportional to motor speed are a light source and a photoelectric device cooperating with said rotor to provide an optoelectronic signal generating system.
Claim 12
Dependent Claim
74 words
A tape drive as defined in claim 10, in which said features at or near the periphery of said rotor are a series of openings circumferentially disposed at or near the edge of the rotor and in which said fixed elements also include means for reflecting light received through said openings from said light source back through one of said openings to said photoelectric device, said photoelectric device being adjacent to said light source.
Claim 13
Dependent Claim
217 words
Tape drive for a magnetic tape cassette recorder and/or player having both steady speed and low inertia, as well as small axial dimension, comprising in combination: a direct current motor of the axial air-gap type having an annular multipolar permanent magnet stator and a substantially disc shaped rotor of non-magnetic material having a rotor-supporting shaft and a second shaft concentric with said rotor-supporting shaft, said second shaft being mounted so as to be shiftable axially with respect to said rotor and slidably keyed to the rotor-supporting shaft so as to be driven by said rotor and having an extension disposed and shaped as a tape transport capstan; means, including axially shiftable take-up and pay-out spindles for insertion in a cassette and a pressure roller facing said capstan extension of said second shaft, for driving of tape contained in the cassette past at least one magnetic transducer head at a rate determined by the rotation rate of said second shaft, said spindles being parallel to said second shaft, and means for causing and requiring said spindles to be axially shiftable together in common with axial shift of said second shaft, thereby providing for movement of said tape drive between an idle position and an operating position, all the movable portions of said motor having low moment of inertia.
Claim 14
Dependent Claim
217 words
Tape drive for a magnetic tape cassette recorder and/or player having both steady speed and low inertia, as well as small axial dimension, comprising in combination: a direct current motor of the axial air-gap type having an annular multipolar permanent magnet stator and a substantially disc shaped rotor of non-magnetic material having a rotor-supporting shaft and a second shaft concentric with said rotor-supporting shaft, said second shaft being mounted so as to be shiftable axially with respect to said rotor and slidably keyed to the rotor-supporting shaft so as to be driven by said rotor and having an extension disposed and shaped as a tape transport capstan; means, including axially shiftable take-up and pay-out spindles for insertion in a cassette and a pressure roller facing said capstan extension of said second shaft, for driving of tape contained in the cassette past at least one magnetic transducer head at a rate determined by the rotation rate of said second shaft, said spindles being parallel to said second shaft, and means for causing and requiring said spindles to be axially shiftable together in common with axial shift of said second shaft, thereby providing for movement of said tape drive between an idle position and an operating position, all the movable portions of said motor having low moment of inertia.
Claim 15
Dependent Claim
128 words
A tape drive as defined in claim 12, in which axial shiftability of said second shaft with respect to said rotor is provided by the combination, within the structure of said motor of: a central bearing inside and coaxial with said stator, having an internal movable portion and an external fixed portion, said rotor being affixed to said movable internal portion of said central bearing, said movable internal portion of said bearing being hollow and provided with grooves running parallel to the axis of said movable portion of said bearing, and radial projections (15) provided on said second shaft slidably engaged in said grooves (14) for confining the relative movement of said second shaft and said movable part of said bearing to relative displacement in an axial direction.
Claim 16
Dependent Claim
41 words
A tape drive as defined in claim 13, including spring members (16) in the hollow portion of said movable portion of said bearing for urging said projections (15) of said second shaft axially towards an end position abutment in said bearing
Claim 17
Dependent Claim
39 words
A tape drive as defined in claim 12, in which said driving means includes a friction wheel drive connection and a slip coupling for driving one of said spindles as a take-up spindle by the force of said motor.
Claim 18
Dependent Claim
41 words
A tape drive as defined in claim 12, in which said driving means includes at least one drive belt (22) and a slip coupling for driving one of said spindles as a take-up spindle (3) by the force of said motor.
Claim 19
Dependent Claim
94 words
A tape drive as defined in claim 12, in which said disc shaped rotor (11) is constituted of at least one thin insulating plate on which conducting paths are printed and in which said conducting paths run radially in the annular portion of said disc which is within the same radial distance range from the motor axis as the annular permanent magnet serving as the stator of the motor and, in the space enclosed by the said annular permanent magnet (10), resiliently urged contact members ride on respective contact areas of said rotor (11).
Claim 20
Dependent Claim
127 words
A tape drive as defined in claim 12, comprising also speed regulating means (25) responsive to an electrical signal representative of the speed of the rotor of the motor for controlling the voltage at which current is supplied to the rotor of the motor in such a way as to maintain the rotor speed constant, and means for generating an electrical signal having a characteristic proportional to motor speed composed of features at or near the periphery of said rotor and a sensor device in a nonrevolving position in said motor adjacent to said rotor for producing said signal in response to passage of said features past said sensor device, said sensor device having an output connected to a control input (26) of said speed regulating means.
Claim 21
Dependent Claim
97 words
A tape drive as defined in claim 18, in which said features of said rotor are openings circumferentially disposed at or near the edge of the rotor, and in which there are provided, within said motor structure, means for radiating light through said openings and means for reflecting light so radiated towards said light radiating means, and in which said sensor is located adjacent to said light radiating means for generating said electrical signal in response to light so reflected, whereby said electrical signal is produced in a manner giving it a frequency proportional to motor speed.
Claim 22
Dependent Claim
141 words
A tape drive as defined in claim 12, which also comprises means for reversing the polarity of the current supplied to said motor and in which said driving means comprises a slip coupling for driving one of said spindles as a take-up spindle (3) by the force of said motor, an idler wheel (5) having a laterally shiftable axle and means for shifting the axle of said idler wheel in response to the placing of the tape drive in the fast rewind mode upon operation of said means for reversing supply current polarity, and wheels (3a,4a) or rollers respectively affixed to said spindles (3,4) for transfer of rotary motion force between said spindles for shifting the axle of said idler wheel (5) to disengage the idler wheel in response to the tape drive being taken out of the fast rewind condition.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-07-03 | 1982-01-02 | 1982-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-03 | 1986-01-02 | 1986-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-03 | 1990-01-02 | 1990-07-04 | $7700.00 | Window Closed / Lapsed |