US4135721A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Video disc player
Assignee: US Philips Corp
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Filing: 1977-04-01
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Granted: 1979-01-23
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Expires: 1997-04-01
Abstract
Abstract The spindle motor of a video disc player is simultaneously disengaged from the motor power source and connected to an electromagnetic safety device for maintaining the cover of the player in a safety position by virtue of the induction current generated by the freely spinning motor until the motor speed is reduced to a safe angular velocity. An electromagnetically operated brake powered by the inductive current generated by the motor assists in reducing the motor velocity.
Inventors
- 👤 Eduard Camerik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:07
CPC Classifications
G; G11; G11B; G11B33/00; G11B33/02; G11B19/00; G11B19/20
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
262 words
Apparatus for enclosing a rotating disc, comprising a housing, spindle means in said housing for supporting said disc, spindle motor means in said housing for rotating said spindle, a cover pivotally mounted on said housing and displaceable to a fully open position, a fully closed position and a safety position intermediate said fully opened and fully closed positions, controllable voltage supply means for selectively providing electrical power to said spindle motor menss, cam operated switch means for causing the electrical power from said voltate supply means to energize said motor means in response to the movement of the cover to its fully closed position and for stopping the energizing of said motor means in response to the movement of the cover to its safety position and the fully closed position, braking means for reducing the speed of the motor means in response to the movement of said cover to its safety position, electromagnetic safety means actuable by electrical current therethrough for preventing the cover from being released from said safety position to said fully open position, and safety circuit means for connecting said electromagnetic safety means to said motor means in response to the movement of said cover to its safety position, said motor means further comprising means for inductively generating electrical current in response to rotation of said motor in the absence of electrical power from said voltage supply means, whereby said electromagnetic safety means is actuated to prevent the cover from being released from the safety position until the speed of the motor has decreased to a predetermined rotational speed.
Claim 2
Dependent Claim
262 words
Apparatus for enclosing a rotating disc, comprising a housing, spindle means in said housing for supporting said disc, spindle motor means in said housing for rotating said spindle, a cover pivotally mounted on said housing and displaceable to a fully open position, a fully closed position and a safety position intermediate said fully opened and fully closed positions, controllable voltage supply means for selectively providing electrical power to said spindle motor menss, cam operated switch means for causing the electrical power from said voltate supply means to energize said motor means in response to the movement of the cover to its fully closed position and for stopping the energizing of said motor means in response to the movement of the cover to its safety position and the fully closed position, braking means for reducing the speed of the motor means in response to the movement of said cover to its safety position, electromagnetic safety means actuable by electrical current therethrough for preventing the cover from being released from said safety position to said fully open position, and safety circuit means for connecting said electromagnetic safety means to said motor means in response to the movement of said cover to its safety position, said motor means further comprising means for inductively generating electrical current in response to rotation of said motor in the absence of electrical power from said voltage supply means, whereby said electromagnetic safety means is actuated to prevent the cover from being released from the safety position until the speed of the motor has decreased to a predetermined rotational speed.
Claim 3
Dependent Claim
107 words
Apparatus as recited in claim 1, wherein said braking means comprises a pair of friction member means actuable to engaged and disengaged positions for reducing the speed of the motor means when in the engaged position, resilient means for biassing said friction member means towards said disengaged position, and electromagnetic brake actuating means responsive to the movement of said cover to its safety position and to said current inductively generated by said motor means for actuating said friction member means to said engaged position, whereby said braking means reduces the speed of the motor toward said predetermined speed when said cover is moved to the safety position.
Claim 4
Dependent Claim
45 words
Apparatus as recited in claim 1, wherein said safety circuit means comprises a safety switch having movable contacts and stationary contacts actuable by said cover for connecting said motor means to said electromagnetic safety means through said movable and stationary contacts of said safety switch.
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) | 1982-01-22 | 1982-07-24 | 1983-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-01-22 | 1986-07-24 | 1987-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-01-22 | 1990-07-24 | 1991-01-23 | $7700.00 | Window Closed / Lapsed |