Patent US3826446A successfully refreshed from Google Patents.
US3826446A
Expired / Lapsed
US
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Pneumatic tape rewind system
Assignee: Ampex Corp
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Filing: 1972-02-14
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Granted: 1974-07-30
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Expires: 1992-02-14
Abstract
Abstract A magnetic tape transport system is provided in which a capstan used to drive the tape bidirectionally and intermittently during normal operation is coupled to a pressure source so as to disengage from and act as an air bearing with respect to the tape during rewind, permitting the tape to be driven by differences in tension on loops of the tape within a pair of vacuum chambers. The tension differential is produced by an arrangement of valves and conduits which partially vent the interior of the upstream vacuum chamber to atmosphere to maintain the tape loop therein at a nominal short loop position and which vent the interior of the downstream vacuum chamber to atmosphere only when the loop therein becomes too long so as to maintain the loop at an optimum long loop position. Thus capstan drive is eliminated during rewind with system performance being slaved to the performance of the reel motor-servo combinations which function to maintain the tape loops at the nominal positions within the vacuum chambers. During normal operation the venting conduits within the vacuum chambers are blocked by valves to restore normal vacuum tension within the chambers compatible with capstan drive.
Inventors
- 👤 H Jones
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:43
CPC Classifications
G; G06; G06K; G06K13/00; G06K13/18; G06K13/26; G06K13/28; G11; G11B; G11B15/00; G11B15/18; G11B15/38; G11B15/56; G11B15/58
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
330 words
A system for driving an elongated web material through an intermediate region between two storage reels, comprising: at least a pair of pneumatic buffer means for forming low inertia loops in the web material in the interior of the buffer means on opposite sides of the intermediate region; means defining a low friction path for the elongated web material between the buffer means and through the intermediate region, the low friction path allowing the web material to move freely between the buffer means; means responsive to the loop lengths in the buffer means for operating the storage reels to tend to maintain nominal loop lengths therein; means coupled to a closed end of each of the pair of buffer means for providing a reduced pressure at the interior of the buffer means; means associated with one of the buffer means for maintaining the loop of web material adjacent a selected location therein by venting the interior of the buffer means to the exterior thereof except when the loop of web material becomes displaced from the selected location, said means including means coupling the interior thereof at a first opening adjacent the closed end to the interior thereof at a second opening at a location adjacent and on the opposite side of the selected loop location from the closed end, the second opening being a substantial distance from the first opening; and means associated with the other one of the buffer means for maintaining the loop of web material adjacent a selected location therein by venting the interior of the buffer means to the exterior thereof whenever the loop of web material becomes displaced from the selected location, said means including means coupling the interior thereof at a third opening adjacent the closed end to the interior thereof at a fourth opening at a location adjacent and on the same side of the selected loop location as the closed end, the third and fourth openings being completely separated from one another.
Claim 2
Independent Claim
330 words
A system for driving an elongated web material through an intermediate region between two storage reels, comprising: at least a pair of pneumatic buffer means for forming low inertia loops in the web material in the interior of the buffer means on opposite sides of the intermediate region; means defining a low friction path for the elongated web material between the buffer means and through the intermediate region, the low friction path allowing the web material to move freely between the buffer means; means responsive to the loop lengths in the buffer means for operating the storage reels to tend to maintain nominal loop lengths therein; means coupled to a closed end of each of the pair of buffer means for providing a reduced pressure at the interior of the buffer means; means associated with one of the buffer means for maintaining the loop of web material adjacent a selected location therein by venting the interior of the buffer means to the exterior thereof except when the loop of web material becomes displaced from the selected location, said means including means coupling the interior thereof at a first opening adjacent the closed end to the interior thereof at a second opening at a location adjacent and on the opposite side of the selected loop location from the closed end, the second opening being a substantial distance from the first opening; and means associated with the other one of the buffer means for maintaining the loop of web material adjacent a selected location therein by venting the interior of the buffer means to the exterior thereof whenever the loop of web material becomes displaced from the selected location, said means including means coupling the interior thereof at a third opening adjacent the closed end to the interior thereof at a fourth opening at a location adjacent and on the same side of the selected loop location as the closed end, the third and fourth openings being completely separated from one another.
Claim 3
Dependent Claim
59 words
A system in accordance with claim 1, wherein the means coupling the first opening to the second opening comprises a first conduit including means therein for selectively opening and closing the first conduit, and the means coupling the third opening to the fourth opening comprises a second conduit including means therein for selectively opening and closing the second conduit.
Claim 4
Dependent Claim
67 words
A system in accordance with claim 2, wherein the selected loop location within said one of the buffer means is at a selected distance from the closed end thereof to define a short loop and the selected loop location within said other one of the buffer means is at a distance substantially less than said selected distance from the closed end thereof to define a long loop.
Claim 5
Independent Claim
268 words
A system for driving an elongated web material through an intermediate region between two storage reels, comprising: a pair of pneumatic buffer means for forming low inertia loops in the web material on opposite sides of the intermediate region in response to a vacuum condition therein; mEans responsive to the loop lengths in the buffer means for operating the storage reels to tend to maintain nominal loop lengths therein; means within the intermediate region for selective engagement with the web material to drive the web material during a first mode of operation, said driving means being disengaged from the web material during a second mode of operation; means coupled to one of the buffer means for increasing the vacuum condition therein whenever the loop of the web material therein becomes shorther than the nominal length during the second mode of operation, said means comprising means coupling different portions of the interior of the buffer means together and valve means for controlling pressure communication therebetween, the valve means preventing pressure communication during the first mode of operation and permitting pressure communication during the second mode of operation; and means coupled to the other one of the buffer means for decreasing the vacuum condition therein whenever the loop of the web material therein becomes longer than the nominal length during the second mode of operation, said means comprising means coupling different portions of the interior of the buffer means together and valve means for controlling pressure communication therebetween, the valve means preventing pressure communication during the first mode of operation and permitting pressure communication during the second mode of operation.
Claim 6
Independent Claim
268 words
A system for driving an elongated web material through an intermediate region between two storage reels, comprising: a pair of pneumatic buffer means for forming low inertia loops in the web material on opposite sides of the intermediate region in response to a vacuum condition therein; mEans responsive to the loop lengths in the buffer means for operating the storage reels to tend to maintain nominal loop lengths therein; means within the intermediate region for selective engagement with the web material to drive the web material during a first mode of operation, said driving means being disengaged from the web material during a second mode of operation; means coupled to one of the buffer means for increasing the vacuum condition therein whenever the loop of the web material therein becomes shorther than the nominal length during the second mode of operation, said means comprising means coupling different portions of the interior of the buffer means together and valve means for controlling pressure communication therebetween, the valve means preventing pressure communication during the first mode of operation and permitting pressure communication during the second mode of operation; and means coupled to the other one of the buffer means for decreasing the vacuum condition therein whenever the loop of the web material therein becomes longer than the nominal length during the second mode of operation, said means comprising means coupling different portions of the interior of the buffer means together and valve means for controlling pressure communication therebetween, the valve means preventing pressure communication during the first mode of operation and permitting pressure communication during the second mode of operation.
Claim 7
Dependent Claim
257 words
A magnetic tape transport system comprising: first and second tape reels for storing a length of magnetic tape therebetween; transducer means disposed adjacent a path for the magnetic tape at a region intermediate the first and second reels; first and second vacuum chambers disposed on opposite sides of the intermediate region and adjacent the first and second reels respectively for imposing vacuum tension on the tape to form loops therein; first and second reel servos for respectively driving the first and second tape reels so as to maintain loops of selected nominal sizes in the first and second vacuum chambers; at least one capstan within the intermediate region for engaging the tape to drive the tape past the transducer means during normal operation, the capstan being disengaged from the tape and acting as a low friction bearing during rewind of the tape; means coupling the capstan to a vacuum source to enhance engagement with the tape during normal operation and to a pressure source to enhance disengagement from the tape during rewind; means for maintaining the loop within the first vacuum chamber at a nominal short loop size during rewind of the tape including means for increasing vacuum tension on the loop whenever the size thereof becomes smaller than the nominal short loop size; and means for maintaining the loop within the second vacuum chamber at a nominal long loop size during rewind of the tape including means for decreasing vacuum tension on the loop whenever the size thereof becomes larger than the nominal short loop size.
Claim 8
Dependent Claim
257 words
A magnetic tape transport system comprising: first and second tape reels for storing a length of magnetic tape therebetween; transducer means disposed adjacent a path for the magnetic tape at a region intermediate the first and second reels; first and second vacuum chambers disposed on opposite sides of the intermediate region and adjacent the first and second reels respectively for imposing vacuum tension on the tape to form loops therein; first and second reel servos for respectively driving the first and second tape reels so as to maintain loops of selected nominal sizes in the first and second vacuum chambers; at least one capstan within the intermediate region for engaging the tape to drive the tape past the transducer means during normal operation, the capstan being disengaged from the tape and acting as a low friction bearing during rewind of the tape; means coupling the capstan to a vacuum source to enhance engagement with the tape during normal operation and to a pressure source to enhance disengagement from the tape during rewind; means for maintaining the loop within the first vacuum chamber at a nominal short loop size during rewind of the tape including means for increasing vacuum tension on the loop whenever the size thereof becomes smaller than the nominal short loop size; and means for maintaining the loop within the second vacuum chamber at a nominal long loop size during rewind of the tape including means for decreasing vacuum tension on the loop whenever the size thereof becomes larger than the nominal short loop size.
Claim 9
Dependent Claim
160 words
A system in accordance with claim 5, wherein the vacuum tension on the tape is produced by a vacuum source coupled to closed ends of the first and second vacuum chambers, the means for increasing vacuum tension on the loop whenever the size thereof becomes smaller than the nominal short loop size comprises means coupling a first opening in the first vacuum chamber on the opposite side of a nominal short loop position from the closed end of the first vacuum chamber to the interior of the first vacuum chamber adjacent the closed end thereof, and the means for decreasing vacuum tension on the loop whenever the size thereof becomes larger than the nominal long loop size comprises means coupling a second opening in the second vacuum chamber on the same side of a nominal long loop position from the closed end of the second vacuum chamber to the interior of the second vacuum chamber adjacent the closed end thereof.
Claim 10
Dependent Claim
199 words
In a magnetic tape transpOrt system in which tape is intermittently and bidirectionally driven at a nominal speed past transducer means during normal operation, said tape extending between opposite storage reels and associated vacuum chambers which combine with reel servos to form loops of nominal length in the tape, an arrangement for rewinding the tape at a speed greater than the nominal speed comprising means associated with one of the vacuum chambers for coupling the interior thereof to an aperture located at given distance from an open end thereof to define a nominal short loop position and means associated with the other one of the vacuum chambers for coupling the interior thereof to an aperture located at a distance greater than said given distance from an open end thereof to define a nominal long loop position, each of said coupling means comprising a conduit extending between said aperture and another aperture in a wall of the associated vacuum chamber adjacent a source of reduced pressure for the vacuum chamber, and valve means located within each conduit for closing the interior of the conduit during normal operation and for opening the interior of the conduit during rewinding of the tape.
Claim 11
Dependent Claim
199 words
In a magnetic tape transpOrt system in which tape is intermittently and bidirectionally driven at a nominal speed past transducer means during normal operation, said tape extending between opposite storage reels and associated vacuum chambers which combine with reel servos to form loops of nominal length in the tape, an arrangement for rewinding the tape at a speed greater than the nominal speed comprising means associated with one of the vacuum chambers for coupling the interior thereof to an aperture located at given distance from an open end thereof to define a nominal short loop position and means associated with the other one of the vacuum chambers for coupling the interior thereof to an aperture located at a distance greater than said given distance from an open end thereof to define a nominal long loop position, each of said coupling means comprising a conduit extending between said aperture and another aperture in a wall of the associated vacuum chamber adjacent a source of reduced pressure for the vacuum chamber, and valve means located within each conduit for closing the interior of the conduit during normal operation and for opening the interior of the conduit during rewinding of the tape.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-29 | 1978-01-28 | 1978-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-29 | 1982-01-28 | 1982-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-29 | 1986-01-28 | 1986-07-30 | $7700.00 | Window Closed / Lapsed |