US3898693A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Video recorder/reproducer transport using vacuum columns and servos
Assignee: Video Memory Corp
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Filing: 1974-08-26
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Granted: 1975-08-05
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Expires: 1994-08-26
Abstract
Abstract An improved tape transport for use in the magnetic tape recording and reproducing of high frequency signals, such as video signals. The transport is adapted to include a helical scanner head assembly for recording and reproducing signals on the tape in a helical scan format. Vacuum chambers are included for handling the tape passing to and from the scanner head assembly. A vacuum chamber is positioned intermediate the tape take-up source and the capstan, and another vacuum chamber is positioned intermediate the scanner head assembly and the tape supply source. The scanner head assembly supports a separate record head and a separate playback head spaced apart relative to one another such that record and playback may be realized simultaneously.
Inventors
- 👤 David T L Chang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 11:22
CPC Classifications
G; G11; G11B; G11B15/00; G11B15/56; G11B15/58; G11B27/00; G11B27/02; G11B27/022; G11B27/024; H; H04; H04N; H04N17/00; H04N17/06
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
290 words
A video magnetic tape recording/playback transport apparatus, comprising in combination: a tape supply means for providing a supply of magnetic recording tape; a tape take-up means for receiving tape supplied by said tape supply means; a drive capstan means intermediate the tape supply means and the tape take-up means for driving tape intermediate the tape supply means and the tape take-up means; a helical head scanner assembly positioned intermediate said capstan and one of said tape means and having a pair of substantially cylindrical coaxially closely spaced drums having a clearance gap therebetween, one of said drums being fixed and the other being rotatable relative to the fixed drum, the head scanner assembly including a record head and a playback head angularly spaced relative to one another and means for driving said heads in a rotary path about the axis of the drums; means for guiding magnetic tape along a helical path about said drums extending substantially diagonally across said gap and the path of Said heads; means for rotating said rotatable drum and said heads about the axis of the drums; a first V-shaped vacuum chamber intermediate the helical head scanner and the tape supply means with first sensing means for sensing the position of tape within said first chamber and generating first signals responsive to the position of tape within said first chamber; a second V-shaped vacuum chamber intermediate the helical head scanner and the tape take-up means with second sensing means for sensing the position of tape within said second chamber and generating second signals responsive to the position of tape within said second chamber; and servo control means responsive to the first signals and the second signals for generating servo control signals to the drive capstan.
Claim 2
Dependent Claim
290 words
A video magnetic tape recording/playback transport apparatus, comprising in combination: a tape supply means for providing a supply of magnetic recording tape; a tape take-up means for receiving tape supplied by said tape supply means; a drive capstan means intermediate the tape supply means and the tape take-up means for driving tape intermediate the tape supply means and the tape take-up means; a helical head scanner assembly positioned intermediate said capstan and one of said tape means and having a pair of substantially cylindrical coaxially closely spaced drums having a clearance gap therebetween, one of said drums being fixed and the other being rotatable relative to the fixed drum, the head scanner assembly including a record head and a playback head angularly spaced relative to one another and means for driving said heads in a rotary path about the axis of the drums; means for guiding magnetic tape along a helical path about said drums extending substantially diagonally across said gap and the path of Said heads; means for rotating said rotatable drum and said heads about the axis of the drums; a first V-shaped vacuum chamber intermediate the helical head scanner and the tape supply means with first sensing means for sensing the position of tape within said first chamber and generating first signals responsive to the position of tape within said first chamber; a second V-shaped vacuum chamber intermediate the helical head scanner and the tape take-up means with second sensing means for sensing the position of tape within said second chamber and generating second signals responsive to the position of tape within said second chamber; and servo control means responsive to the first signals and the second signals for generating servo control signals to the drive capstan.
Claim 3
Dependent Claim
40 words
A video magnetic tape recorder/playback transport apparatus as recited in claim 1 wherein the record head is adapted to record tracks diagonally on magnetic tape, which record tracks are of a width greater than the width of the playback track.
Claim 4
Dependent Claim
46 words
A video magnetic tape recorder/playback transport apparatus as recited in claim 1 wherein each of said vacuum chambers include means for varying the pressure within the chambers such that the tape tension is a function of the cross-sectional area of the chamber and the pressure differential.
Claim 5
Dependent Claim
40 words
A video magnetic tape recorder/playback transport apparatus as recited in claim 3 wherein the record head is adapted to record tracks diagonally on magnetic tape which record tracks are of a width greater than the width of the playback track.
Claim 6
Dependent Claim
106 words
A video magnetic tape recorder/playback transport apparatus as recited in claim 3 wherein each of said vacuum chambers comprise a first channel for receiving a loop of said tape and an evacuation channel adjacent to said first channel, a partition wall separating said first and said evacuation channels, a plurality of spaced apart bleeding openings extending through said partition wall, said bleeding openings being spaced apart such that as the length of the tape loop within the chamber varies, the number of bleeding apertures on opposite sides of the tape varies, thereby varying the pressure differential on opposing sides of the tape looped in the chamber.
Claim 7
Dependent Claim
94 words
A video magnetic tape recorder/playback transport apparatus as recited in claim 5 wherein each of said vacuum chambers includes a blackened cover over said first channel, a photo-detector means extending along a side wall of the first channel adjacent to the travel path for a tape loop within the chamber, a light source within the evacuation chamber for generating light within the first channel, said photo-detector generating responsive electrical signals dependent upon the degree of area of said photodetector means blocked off from said generated light by the magnetic tape loop within the chamber.
Claim 8
Dependent Claim
53 words
A video magnetic tape recorder/playback transport apparatus as recited in claim 4 wherein each of the drums are comprised of a metallic material with the peripheral surface coated with a layer of inert, insoluble polymer to provide a low coefficient of friction between the surface of the drums and the tape transported thereover.
Claim 9
Dependent Claim
49 words
A video magnetic tape recorder/playback transport apparatus as recited in claim 1 wherein the head scanner assembly includes an erase head angularly spaced relative to the record head and the playback head, said erase head being movable in the rotary path simultaneously with movement of the record and playback.
Claim 10
Dependent Claim
63 words
A video magnetic tape recorder/playback transport apparatus as recited in claim 8 wherein the record head is adapted to record tracks diagonally on magnetic tape which record tracks are of a width greater than the width of the playback track, and the erase head is adapted to erase recorded tracks of a width at least equal to the width of the record head.
Claim 11
Dependent Claim
93 words
A video magnetic tape recorder/playback transport apparatus as recited in claim 1 wherein a first stationary guide is positioned immediately adjacent to the periphery of the helical head scanner assembly to guide tape entering the helical path about said drums; a second stationary guide is positioned immediately adjacent to the periphery of the helical head scanner assembly to guide tape exiting the helical path about said drums, the lateral spacing between said first and second stationary guides being such the the tape wrapped about the scanner assembly is substantially, but less, than 360*.
Claim 12
Dependent Claim
42 words
A video magnetic tape recorder/playback transport apparatus as recited in claim 1 wherein the playback head is coupled to signal processing electronics and the record head is coupled to signal processing electronics such that playback and recording operations may be conducted simultaneously.
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) | 1978-08-04 | 1979-02-03 | 1979-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-04 | 1983-02-03 | 1983-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-04 | 1987-02-03 | 1987-08-05 | $7700.00 | Window Closed / Lapsed |