US3825948A — High speed thermal duplication of magnetic tape

Claim 1

Independent Claim 198 words

A system for high speed thermal duplication of a master magnetic tape onto a copy magnetic tape comprising: master tape transport means for guiding a master tape between supply and pick-up stations in a predetermined master tape path; copy tape transport means for guiding a copy tape between supply and pickup stations in a predetermined copy tape path, said copy tape path and master tape path being sustantially coincident over a predetermined length; clamping means positioned at the coincident master tape and copy tape paths for pressure clamping a master tape and copy tape in intimate contact; heater means positioned along the copy tape path upstream from the clamping means for heating a copy tape transported by the copy tape transport means; measuring means for measuring the length of master tape and copy tape transported past said measuring means in the master tape path and the copy tape path respectively, said measuring means positioned downstream from the clamping means; means for generating a feedback control signal proportioned to the measured length difference between said master tape and copy tape; and means for controlling the tension on one of said tapes in accordance with said difference feedback control signal.

Claim 2

Independent Claim 198 words

A system for high speed thermal duplication of a master magnetic tape onto a copy magnetic tape comprising: master tape transport means for guiding a master tape between supply and pick-up stations in a predetermined master tape path; copy tape transport means for guiding a copy tape between supply and pickup stations in a predetermined copy tape path, said copy tape path and master tape path being sustantially coincident over a predetermined length; clamping means positioned at the coincident master tape and copy tape paths for pressure clamping a master tape and copy tape in intimate contact; heater means positioned along the copy tape path upstream from the clamping means for heating a copy tape transported by the copy tape transport means; measuring means for measuring the length of master tape and copy tape transported past said measuring means in the master tape path and the copy tape path respectively, said measuring means positioned downstream from the clamping means; means for generating a feedback control signal proportioned to the measured length difference between said master tape and copy tape; and means for controlling the tension on one of said tapes in accordance with said difference feedback control signal.

Claim 3

Dependent Claim 140 words

A system for thermal duplication of magnetic tape as set forth in claim 1 wherein the means for controlling tension on one of said tapes in accordance with the difference feedback control signal comprises a vacuum column having sidewalls open at one end and closed at the other end then tapering from a greater width from the open end to a lesser width at the closed end, said column positioned for receiving a tape across the open end and provided with means for applying low pressure to the closed end for drawing the tape into the column, and means for controlling the depth of the tape in the column whereby the surface area of the tape is exposed to low pressure and therefore the tension of the tape varies according to the controlled depth of the tape in the column.

Claim 4

Dependent Claim 120 words

A system for thermal duplication of magnetic tape as set forth in claim 2 wherein is provided a first air guide in the tape path at the downstream side of the open end of the column for guiding said tape at one side of the open end of the column and wherein is pRovided a second movable air guide in the tape path adjacent and upstream from said first air guide and means for moving said second air guide laterally across the open end of the vacuum column whereby a tape positioned around said air guides is held across the open end of the vacuum column by the movable air guide during loading of the tape into the vacuum column.

Claim 5

Dependent Claim 116 words

A system for thermal duplication for magnetic tape as set forth in claim 1 wherein a pair of vacuum columns is provided in each of the master tape and copy tape paths, one downstream from the supply station and one upstream from the pick-up station for isolating the master tape and copy tape in their respective transport paths from the supply stations and pick-up stations, respectively, and wherein there is further provided in each of the master tape path and the copy tape path at least one guide post, and means for clamping the respective tape against said guide post to maintain the tape in stationary position during loading of the tapes into the vacuum columns.

Claim 6

Dependent Claim 73 words

A system for thermal duplication of magnetic tape as set forth in claim 4 wherein said clamping means comprises a piston terminating in a face conforming to the shape of the guide post against which a tape is to be clamped, and resilient strips formed along the terminal face of said piston for gripping the tape without injury, and a pneumatic cylinder for driving said piston against the tape and the guide post.

Claim 7

Dependent Claim 49 words

A system for thermal duplication of magnetic tape as set forth in claim 1 where in is provided in the copy tape path upstream from said heating means, a movable air guide for engaging and disengaging the copy tape with a copy tape contacting surface of the heating means.

Claim 8

Dependent Claim 47 words

A system for thermal duplication of magnetic tape as set forth in claim 1 wherein said measuring means comprises first and second spindles interposed in the master tape and the copy tape paths, respectively, and first and second tachometers coupled respectively with the axes of said spindles.

Claim 9

Independent Claim 171 words

A system for thermal duplication of magnetic tape comprising: master tape transport means for guiding a master tape along a predetermined path from a supply station to a pick-up station; copy tape transport means for guiding a copy tape over a predetermined path from the supply station to a pick-up station, the copy tape and master tape paths being substantially coincident over a predetermined length; air clamp means for applying high pressure air against the outside of the master tape and the copy tape, respectively, at the coincident path length, the air clamp comprising opposed, spaced apart air pressure chambers formed with porous surfaces along the opposing sides of the air pressure chambers dividing the coincident master tape and copy tape path lengths, at least one of the porous surfaces providing a resilient surface for yielding in response to variation in the thickness of tape passing between the porous surfaces to thereby prevent damage to the tapes; and heating means positioned in the copy tape path upstream from the clamping means.

Claim 10

Independent Claim 171 words

A system for thermal duplication of magnetic tape comprising: master tape transport means for guiding a master tape along a predetermined path from a supply station to a pick-up station; copy tape transport means for guiding a copy tape over a predetermined path from the supply station to a pick-up station, the copy tape and master tape paths being substantially coincident over a predetermined length; air clamp means for applying high pressure air against the outside of the master tape and the copy tape, respectively, at the coincident path length, the air clamp comprising opposed, spaced apart air pressure chambers formed with porous surfaces along the opposing sides of the air pressure chambers dividing the coincident master tape and copy tape path lengths, at least one of the porous surfaces providing a resilient surface for yielding in response to variation in the thickness of tape passing between the porous surfaces to thereby prevent damage to the tapes; and heating means positioned in the copy tape path upstream from the clamping means.

Claim 11

Dependent Claim 38 words

A system for thermal duplication of magnetic tape as set forth in claim 8 wherein the at least one yielding surface of the pressure chambers dividing the air clamp comprises a porous surface formed of a resilient material.

Claim 12

Dependent Claim 20 words

A system for thermal duplication of magnetic tape as set forth in claim 9 wherein said resilient material comprises Teflon-felt.

Claim 13

Dependent Claim 58 words

A system for thermal duplication of magnetic tape as set forth in claim 8 wherein the at least one yielding surface comprises a movable porous surface forming a side of an air pressure chamber, and means spring mounting the movable surface for motion back and forth in the walls of the chamber in response to tape thickness variations.

Claim 14

Dependent Claim 64 words

A system for thermal duplication of magnetic tape as set forth in claim 8 wherein the at least one yielding surface of an air pressure chamber is formed by a freely movable porous side wall mounted for movinG back and forth between the ends of the air chamber in response to air pressure on one side and tape thickness variations on the other side.

Claim 15

Dependent Claim 56 words

A system for thermal duplication of magnetic tape as set forth in claim 8 wherein one of said porous surfaces includes holes having configurations leading from small openings on the inside of the air pressure chamber to larger outlets on the outside for distributing air pressure along the surface of tapes travelling through the air clamp.

Claim 16

Independent Claim 159 words

A system for thermal duplication of magnetic tape comprising: master tape transport means for guiding a master tape along a predetermined path from a supply station to a take-up station; copy tape transport means for guiding a copy tape along a predetermined path from a supply station to a take-up station, the copy tape path and the master tape path being substantially coincident over a predetermined length; air clamp means for applying high pressure air to the outsides of the master tape and the copy tape at the coincident path length comprising a pair of opposed spaced apart air pressure chambers defining the coincident master tape and copy tape paths between opposed sides of the pressure chambers, one of said opposing sides comprising a porous surface, the opposing side of the other air pressure chamber being open for direct delivery of high pressure air; and heating means positioned in the copy tape path upstream from the air clamp means.

Claim 17

Independent Claim 159 words

A system for thermal duplication of magnetic tape comprising: master tape transport means for guiding a master tape along a predetermined path from a supply station to a take-up station; copy tape transport means for guiding a copy tape along a predetermined path from a supply station to a take-up station, the copy tape path and the master tape path being substantially coincident over a predetermined length; air clamp means for applying high pressure air to the outsides of the master tape and the copy tape at the coincident path length comprising a pair of opposed spaced apart air pressure chambers defining the coincident master tape and copy tape paths between opposed sides of the pressure chambers, one of said opposing sides comprising a porous surface, the opposing side of the other air pressure chamber being open for direct delivery of high pressure air; and heating means positioned in the copy tape path upstream from the air clamp means.

Claim 18

Dependent Claim 48 words

A system for thermal duplication of magnetic tape as set forth in claim 14 wherein a spring biased guide member is provided at each end of the open side of the open air clamp, said spring biased guide members resting against a tape passing through the air clamp.

Claim 19

Dependent Claim 63 words

A system for thermal duplication of magnetic tape as set forth in claim 14 wherein the air pressure chamber formed with said open side is also formed with a row of angularly directed holes at each end of the air clamp in the direction of the tape paths to generate an air bearing for tape passing into and out of the air clamp.

Claim 20

Independent Claim 180 words

A system for thermal duplication of magnetic tape comprising: master tape transport means for transporting a master tape over a predetermined path between a supply station and a take-up station; copy tape transport means for transporting a copy tape over a predetermined path between the supply station and a take-up station, the master tape and the copy tape paths being substantially coincident over a predetermined length; air clamp means for applying pressure air to the outsides of the master tape and the copy tape at the substantially coincident path length, the air clamp means comprising first and second opposed spaced apart air pressure chambers, the chambers being arranged with opposing sides defining path lengths of substantial coincidence and for delivering the high pressure air, track means mounting the air pressure chambers for movement toward and away from the coincident master and copy tape paths; means for moving said air pressure chambers along the track means toward and away from the coincident master and copy tape paths; and heating means positioned in the copy tape path upstream from the clamp means.

Claim 21

Independent Claim 180 words

A system for thermal duplication of magnetic tape comprising: master tape transport means for transporting a master tape over a predetermined path between a supply station and a take-up station; copy tape transport means for transporting a copy tape over a predetermined path between the supply station and a take-up station, the master tape and the copy tape paths being substantially coincident over a predetermined length; air clamp means for applying pressure air to the outsides of the master tape and the copy tape at the substantially coincident path length, the air clamp means comprising first and second opposed spaced apart air pressure chambers, the chambers being arranged with opposing sides defining path lengths of substantial coincidence and for delivering the high pressure air, track means mounting the air pressure chambers for movement toward and away from the coincident master and copy tape paths; means for moving said air pressure chambers along the track means toward and away from the coincident master and copy tape paths; and heating means positioned in the copy tape path upstream from the clamp means.

Claim 22

Dependent Claim 87 words

A system for the thermal duplication of magnetic tape as set forth in claim 17 wherein the means for moving the air pressure chambers toward and away from the coincident tape paths comprises first and second lever arm means coupled at one end respectively to the first and second air pressure chambers and coupled at the opposite ends to a block and means for reciprocating the block for actuating the lever arms and thereby move the first and second air pressure chambers along their respective track means.

Claim 23

Dependent Claim 25 words

A system for thermal duplication of magnetic tape as set forth in claim 18 wherein the means for reciprocating the block comprises a pneumatic actuator.

Claim 24

Dependent Claim 22 words

A system according to claim 18 wherein the means for reciprocating the block comprises guide bar means slideably engaged by the block.

Claim 25

Dependent Claim 31 words

A system for the tHermal duplication of magnetic tape as set forth in claim 18 wherein at least one of the first and second lever arm means comprises a Vernier turnbuckle.

Claim 26

Dependent Claim 90 words

A system for thermal duplication of magnetic tape as set forth in claim 21 wherein the Vernier turnbuckle comprises a first bolt with a thread of a first pitch, a second bolt with a thread of a second pitch different from said first pitch, the threads having like directions, and an elongate nut simultaneously coupled with the first and second bolts at each end of the nut, the nut being formed with mating threads of the first pitch in one end and of the second pitch at the other end.

Claim 27

Independent Claim 196 words

A system for the thermal duplication of magnetic tape comprising: master tape transport means for driving a master tape along a predetermined path from a supply station to a take-up station; copy tape transport means for driving a copy tape along a predetermined path from a supply station to a take-up station, the master and the copy tape paths coinciding over a predetermined length; and a transfer module comprising air clamp means for applying high pressure air to the outsides of the master tape and the copy tape at the coincident path length, heating means positioned in the copy tape path upstream from the air clamp means, master tape guide means positioned upstream of the clamp means, and cooling means in the master tape and the copy tape paths downstream from the air clamp means, a support plate removably mounted to a console and mounting at least some of the air clamp means, the heating means, the cooling means and the guide means for interchanging the heating means, air clamp means, cooling means and the guide means to accommodate magnetic tapes of different widths and to provide access to them for routine maintenance and the like.

Claim 28

Independent Claim 196 words

A system for the thermal duplication of magnetic tape comprising: master tape transport means for driving a master tape along a predetermined path from a supply station to a take-up station; copy tape transport means for driving a copy tape along a predetermined path from a supply station to a take-up station, the master and the copy tape paths coinciding over a predetermined length; and a transfer module comprising air clamp means for applying high pressure air to the outsides of the master tape and the copy tape at the coincident path length, heating means positioned in the copy tape path upstream from the air clamp means, master tape guide means positioned upstream of the clamp means, and cooling means in the master tape and the copy tape paths downstream from the air clamp means, a support plate removably mounted to a console and mounting at least some of the air clamp means, the heating means, the cooling means and the guide means for interchanging the heating means, air clamp means, cooling means and the guide means to accommodate magnetic tapes of different widths and to provide access to them for routine maintenance and the like.

Claim 29

Dependent Claim 68 words

A system for the thermal duplication of magnetic tape as set forth in claim 23 wherein the supply and pick-up stations of the master tape transport and copy tape transport respectively comprise supply reel and take-up reel stations, each reel station including an interchangeable reel hold down adapter which is removable and replaceable for accommodating reels for tapes of different widths or for accommodating reels having differing configurations.

Claim 30

Dependent Claim 104 words

A system for the thermal duplication of magnetic tape as set forth in claim 23 wherein the air clamp means comprises first and second opposed spaced apart air pressure chambers having opposing sides defining the coincident master tape and copy tape paths and for delivering high pressure air to the outside of the tapes as they pass through the clamp, the air pressure chambers being disposed on tracks mounted to the support plate for motion toward and away from the incident path length, and wherein the system includes means mounted to the support plate for reciprocating the air pressure chambers on the respective tracks.

Claim 31

Dependent Claim 58 words

A system for the thermal duplication of magnetic tape as set forth in claim 25 wherein the means for reciprocating the air pressure chambers on the respective tracks comprises first and second lever arm means removably coupled to the first and second air chambers, respectively, and means for actuating said lever arm to reciprocate the air pressure chambers.

Claim 32

Dependent Claim 257 words

A duplicator for the high speed thermal duplication of magnetic tape comprising: master tape transport means for guiding a master tape along a predetermined path from a supply station to a take-up station; copy tape transport means for guiding a copy tape along a predetermined path from a supply station to a take-up station, said master tape and copy tape paths being substantially coincident along a predetermined length; air clamp means for applying high pressure air to the outsides of a master tape and the copy tape at the path coincidence length; heating means comprising an elongate surface of heat conducting material positioned along the copy tape path upstream from the air clamp means; master tape guide means forming a master tape guide surface along tHe master tape path upstream from the air clamp means; means defining a hardened, wear resistant flat surface mounting the master tape transport means, copy tape transport means, air clamp means, heating means and master tape guide means and forming an index surface for an edge of a master tape and of the copy tape: a downwardly biased plate mounted over the heating means and extendingin beyond said heating means over the copy tape path for resting against the upper surface of the copy tape and indexing the copy tape against the flat surface; and a second downwardly biased plate mounted over the master tape guide and extending over the master tape path for resting against the upper surface of a master tape and indexing the copy tape against the flat surface.

Claim 33

Dependent Claim 257 words

A duplicator for the high speed thermal duplication of magnetic tape comprising: master tape transport means for guiding a master tape along a predetermined path from a supply station to a take-up station; copy tape transport means for guiding a copy tape along a predetermined path from a supply station to a take-up station, said master tape and copy tape paths being substantially coincident along a predetermined length; air clamp means for applying high pressure air to the outsides of a master tape and the copy tape at the path coincidence length; heating means comprising an elongate surface of heat conducting material positioned along the copy tape path upstream from the air clamp means; master tape guide means forming a master tape guide surface along tHe master tape path upstream from the air clamp means; means defining a hardened, wear resistant flat surface mounting the master tape transport means, copy tape transport means, air clamp means, heating means and master tape guide means and forming an index surface for an edge of a master tape and of the copy tape: a downwardly biased plate mounted over the heating means and extendingin beyond said heating means over the copy tape path for resting against the upper surface of the copy tape and indexing the copy tape against the flat surface; and a second downwardly biased plate mounted over the master tape guide and extending over the master tape path for resting against the upper surface of a master tape and indexing the copy tape against the flat surface.

Claim 34

Dependent Claim 39 words

A duplicator as set forth in claim 27 wherein each of the first and second downwardly biased plates is loosely mounted on vertically disposed guide means for up and down motion in a direction perpendicular to the flat surface.

Claim 35

Dependent Claim 19 words

A duplicator as set forth in claim 28 wherein said first and second downwardly biased plates are spring biased.

Claim 36

Dependent Claim 21 words

A duplicator as set forth in claim 27 wherein the first and second downwardly biased plates are biased downwardly by gravity.

Claim 37

Dependent Claim 36 words

A duplicator as set forth in claim 27 wherein a surface of each of the downwardly biased plates includes spaced-apart protrusions overlying the respective tapes so that the protrusions rest against upper edges of the tapes.

Claim 38

Dependent Claim 95 words

A duplicator as set forth in claim 27 wherein each of said heating means and master tape guide means includes a curved surface along the copy tape and master tape paths, respectively, and wherein the heating means surface includes at least one opening at its upstream end subjected to a vacuum, and the master guide means surface includes at its upstream end at least one opening for delivering air pressure to insure intimate contact between the copy tape and the heating means surface and to form an air bearing surface for the master tape, respectively.

Claim 39

Independent Claim 115 words

A method for controlling signal distortion during thermal magnetic tape duplication from a master tape to a copy tape in which the signal recorded on a master tape is duplicated on a heated copy tape in a transfer area comprising: measuring the length of master tape issuing from the transfer area; generating a signal proportional to the length of master tape being measured; measuring the length of copy tape issuing from the transfer area; generating a signal proportional to the length of copy tape measured; generating a signal proportional to the difference of the two signals; and controlling the tension of the copy tape upstream from the transfer area in accordance with said difference signal.

Claim 40

Independent Claim 115 words

A method for controlling signal distortion during thermal magnetic tape duplication from a master tape to a copy tape in which the signal recorded on a master tape is duplicated on a heated copy tape in a transfer area comprising: measuring the length of master tape issuing from the transfer area; generating a signal proportional to the length of master tape being measured; measuring the length of copy tape issuing from the transfer area; generating a signal proportional to the length of copy tape measured; generating a signal proportional to the difference of the two signals; and controlling the tension of the copy tape upstream from the transfer area in accordance with said difference signal.

Claim 41

Independent Claim 123 words

A method for controlling and eliminating distortion in a duplicated signal transferred from a master tape to a heated copy tape in a transfer area according to a double duplication process comprising: measuring the rate of passage of master tape from the transfer area and generating a signal proportional to the rate of master tape passage; measuring the rate of passage of the copy tape from the transfer area and generating a signal proportional to the rate of copy tape passage; generating a signal proportional to the difference between the rate of passage of the master and of the copy tapes; and controlling the tension of at least one of the tapes upstream from the transfer area in accordance with the difference signal.

Claim 42

Independent Claim 123 words

A method for controlling and eliminating distortion in a duplicated signal transferred from a master tape to a heated copy tape in a transfer area according to a double duplication process comprising: measuring the rate of passage of master tape from the transfer area and generating a signal proportional to the rate of master tape passage; measuring the rate of passage of the copy tape from the transfer area and generating a signal proportional to the rate of copy tape passage; generating a signal proportional to the difference between the rate of passage of the master and of the copy tapes; and controlling the tension of at least one of the tapes upstream from the transfer area in accordance with the difference signal.

Claim 43

Dependent Claim 50 words

A method according to claim 34 wherein the step of controlling the tension comprises the step of subjecting one side of the tape to differential pressures, and including the step of varying the tension by adjusting the length of tape subjected to differential pressures while maintaining the pressure differential constant.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1977-07-22	1978-01-21	1978-07-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1981-07-22	1982-01-21	1982-07-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1985-07-22	1986-01-21	1986-07-23	$7700.00	Window Closed / Lapsed

High speed thermal duplication of magnetic tape

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