Information
-
Patent Grant
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6270031
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Patent Number
6,270,031
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Date Filed
Thursday, December 2, 199925 years ago
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Date Issued
Tuesday, August 7, 200123 years ago
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Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
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US Classifications
Field of Search
US
- 242 358
- 242 346
- 242 3461
- 360 132
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International Classifications
-
Abstract
A tape transport system includes two tape reels, each having a pair of flanges between which the tape is held. The parallel flange pairs position the tape in a direction normal to tape travel across the tape head contact surface. A cam guide is associated with each reel. Each cam guide has a curved surface over which the magnetic tape travels. The curved surface is positioned between the reel flange pair based on the amount of tape wound on the tape reel. The cam is positioned so that magnetic tape contacts the tape head contact surface at substantially the same location for any amount of tape wound on the tape reel.
Description
TECHNICAL FIELD
The present invention relates to guiding magnetic tape past reel flanges and across a tape access head.
BACKGROUND ART
Magnetic tape is commonly used to store voice and data information due to its reliability, cost efficiency, and ease of use. Magnetic tape may be made more useful and cost effective by increasing the density of information stored on the magnetic tape. One method of increasing information density is to decrease the thickness of the tape thereby permitting more tape to be stored in a given volume.
Decreasing the thickness of magnetic tape creates difficulties in a tape transport system. Thinner tape more easily stretches, increasing the possibility of read and write errors. Thin tape is also susceptible to folding, kinking, creasing, curling and other mechanical damage. Thin tape is more easily skewed relative to the tape head. These difficulties are exacerbated by complex tape transport systems requiring rollers, guides, and the like to drive the tape and position the tape relative to the tape head.
What is needed is an effective tape transport system for thin tape. The tape transport system must be able to guide the magnetic tape past the tape head without causing mechanical damage. The tape transport system should further be simple, inexpensive, and easy to maintain.
DISCLOSURE OF INVENTION
It is an object of the present invention to guide thin magnetic tape past a tape head.
It is another object of the present invention to position magnetic tape relative to the tape head.
It is still another object of the present invention to protect magnetic tape from mechanical damage along the tape path.
It is yet another object of the present invention to reduce the complexity of the tape path.
In carrying out the above objects and other objects and features of the present invention, a tape transport system is provided. The tape system includes two tape reels. Each reel has a pair of flanges between which the tape is held. The parallel flange pairs position the tape in a direction normal to tape travel across the tape head contact surface. A cam guide is associated with each reel. Each cam guide has a curved surface over which the magnetic tape travels. The curved surface is positioned between the reel flange pair based on the amount of tape wound on the tape reel. The cam is positioned so that magnetic tape contacts the tape head contact surface at substantially the same location for any amount of tape wound on the tape reel.
In an embodiment of the present invention, each cam guide curved surface is positioned between the reel tape flange pair so that the angle at which the magnetic tape leaves the reel when the reel is fully wound is substantially the same as the angle at which the magnetic tape leaves the reel when the reel is fully unwound.
In another embodiment of the present invention, each cam guide curved surface is positioned between the reel tape flange pair to guide tape near the edges of each flange in a tape direction non-normal with a direction of reel rotation where the tape crosses the flange edges.
In still another embodiment of the present invention, each cam guide curved surface moves completely out from between the flange pair to facilitate loading the associated tape reel into the tape transport system.
A cam for guiding magnetic tape out of a tape reel is also provided. The magnetic tape has an active side onto which information can be written and from which information can be read and a passive side opposite from the active side. The tape reel has two parallel flanges between which the magnetic tape is wound as a cylindrical tape pack. The cam has a curved surface over which travels the magnetic tape passive side. The curved surface fits between the tape reel flanges to guide tape near the tape pack in a path tangential to the tape pack. The cam curved surface moves between the flanges in response to the amount of tape in the tape pack to guide tape near the edges of each flange in a tape direction non-normal with a direction of reel rotation where the tape crosses the flange edges.
A method of guiding magnetic tape past the tape head is also provided. Tape from within a first reel is driven past the tape head an onto a second reel. Curved surfaces are inserted between the flange pairs of each respective reel. Each curved surface guides tape at the edge of the flange pair at a tape angle substantially the same when the reel is fully wound as when fully unwound.
The above objects and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1
is a schematic drawing of a tape transport system with a tape head located between two flanged tape reels;
FIG. 2
is a schematic drawing of a tape transport system with a tape head located between two flanged tape reels and two cam tape guides according to an embodiment of the present invention;
FIG. 3
is a schematic drawing of a tape transport system with cam tape guides rotated to allow tape loading according to an embodiment of the present invention; and
FIG. 4
is a detailed drawing of a tape transport system according to an embodiment of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
Referring to
FIG. 1
, a schematic drawing of a tape transport system with a tape head located between two flanged tape reels is shown. A tape transport system, shown generally by
20
, moves magnetic tape
22
past tape head
24
. Tape
22
travels between two reels, shown generally by
26
and
28
. Reels
26
,
28
may be contained within a tape cassette. Alternatively, one or both of reels
26
,
28
may be held within a tape cartridge. As will be recognized by one of ordinary skill in the art, the present invention will operate with a variety of means for holding tape
22
. Each reel
26
,
28
includes a hub
30
about which tape
22
is wound to form tape pack
32
. Each reel
26
,
28
also includes a pair of flanges
34
on either side of tape pack
32
between which tape
22
is held. In tape transport system
20
, tape
22
leaves first reel
28
, passes over curved contact surface
36
on tape head
24
, then enters second reel
26
. Flange pair
34
on each reel
26
,
28
positions tape
22
on contact surface
36
in a direction normal to the direction of tape travel over contact surface
36
. Typically, the tape is driven by tension from receiving reel
26
. Receiving reel
26
may be driven by a tape drive, not shown, such as an electric motor. Various tape drives are well known in the art of tape transport systems.
Tape transport system
20
eliminates the need for a complex tape path including rollers, guides, pins, and the like, which may stretch or otherwise damage tape
22
. Hence, tape transport system
20
presents an alternative to traditional tape transport systems for thin magnetic tape
22
. However, tape transport system
20
has two difficulties which may limit effectiveness for use with thin tape. First, the portion of contact surface
36
covered by tape
22
depends on the amount of tape wound on each reel
26
,
28
. Second, tape
22
may leave each reel
26
,
28
normal to the direction of motion of reel
26
,
28
, creating stresses on the edges of tape
22
.
The varying coverage of contact surface
36
by tape
22
is caused by directly feeding tape
22
from reel
26
,
28
to tape head
24
. Tape
22
leaves cylindrical tape pack
32
at an angle tangential with surface of tape pack
32
. Hence, the amount of tape wound on reel
26
,
28
determines the location and angle at which tape
22
crosses flange pair
34
. Since contact surface
36
is curved in the plane of tape travel past tape head
24
, the region of contact between tape
22
and contact surface
36
also depends upon the amount of tape wound on reels
26
,
28
. When tape is fully unwound, as shown for reel
26
, the region of contact with tape head
24
is diminished. When tape is fully wound, as shown for reel
28
, the region of contact with tape head
24
is increased. Since tape head
24
typically includes a plurality of read elements and write elements for accessing tape
22
spaced across contact surface
36
, varying the region of contact between tape
22
and contact surface
36
may affect the operation of tape head
24
.
In addition to affecting the region of contact between tape
22
and contact surface
36
, the amount of tape wound on reels
26
,
28
also affects the stress on the edges of tape
22
created by flange pairs
34
. Tape
22
leaves fully wound reel
28
in direction
40
tangential to both contact surface
36
and tape pack
32
. Tape
22
must pass between flange pair
34
as it leaves reel
28
. Since flange pair
34
positions tape
22
across contact surface
36
, the edges of tape
22
may contact flange pair
34
. Reel
28
, rotating in flange direction
42
, drives flange pair
34
in flange direction
42
at the point where tape
22
crosses the edge of flange pair
34
. The angle between tape direction
38
and flange direction
42
, tape angle
44
, determines the amount of lateral stress placed on the edges of tape
22
by flange pair
34
. As tape angle
44
increases, the lateral stress increases, increasing the potential for damage to the edges of tape
22
. This can be seen for tape angle
46
associated with unwound reel
26
. Flange direction
48
is substantially normal to tape direction
50
, maximizing the stress on the edges of tape
22
.
Referring now to
FIG. 2
, a schematic drawing of a tape transport system with a tape head located between two flanged tape reels and two cam tape guides according to an embodiment of the present invention is shown. A tape transport system, shown generally by
60
, includes cam guide
62
for each reel
26
,
28
. Cam guide
62
includes curved surface
64
over which travels tape
22
when cam guide
62
is in contact with tape
22
. Cam guide
62
is rotatively driven by pin
66
in rotation direction
68
so that curved surface
64
moves between flange pairs
34
. Curved surface
64
is positioned based on the amount of tape
22
wound on reel
26
,
28
so that magnetic tape
22
reaches contact surface
36
at substantially the same location for any amount of tape
22
wound on reel
26
,
28
. Curved surface
64
is most fully inserted into flange pair
34
when a reel is unwound, as indicated by tape pack
70
for reel
26
. As additional tape
22
is wound onto reel
26
, as indicated by tape pack
72
, curved surface
64
is gradually withdrawn from between flange pair
34
. When reel
26
is fully wound, as indicated by tape pack
72
, curved surface
64
no longer contacts tape
22
.
In addition to providing substantially constant coverage of contact surface
36
regardless of the amount of tape wound on reels
26
,
28
, cam guides
62
also maintain a substantially constant tape angle
44
,
46
for tape
22
leaving flange pairs
34
. Curved surface
64
is shaped to keep tape angle
44
,
46
approximately the same as cam guide
62
moves between flange pairs
34
. Tape angle
44
,
46
is a non-normal, acute angle to minimize the stress on the edges of tape
22
. The design of curved surface
64
, the positioning of the cam guide
62
, and the resulting tape angle
44
,
46
depend on the range of sizes for tape pack
32
, the shape of contact surface
36
, and the relative locations of reels
26
,
28
and tape head
24
. Such a design can be easily accomplished by one of ordinary skill in the art of cam design.
Referring now to
FIG. 3
, a schematic drawing of a tape transport system with cam tape guides rotated to allow tape loading is shown. In an embodiment of the present invention, cam guides
62
rotate in direction
68
away from reels
26
,
28
, pulling curved surfaces
64
out from between flange edges
34
. This permits access to tape
22
and reels
26
,
28
for threading tape
22
, changing reels
26
,
28
, loading or unloading a cartridge or cassette containing one or both of reels
26
,
28
, and the like.
Referring now to
FIG. 4
, a detailed drawing of a tape transport system according to an embodiment of the present invention is shown. Flange pair
34
includes upper flanges
90
and lower flanges
92
. Flanges
90
,
92
form parallel surfaces for guiding tape
22
past contact surface
36
. A portion of upper flange
90
for reel
26
is shown cut away to show tape pack
32
and tape
22
riding on curved surface
64
of cam guide
62
. Tape
22
has an active side, shown generally by
94
, onto which data can be written by tape head
24
or from which data can be read by tape head
24
as tape
22
passed contact surface
36
. Tape
22
also has passive side
96
opposite active side
94
which travels over curved surfaces
64
of cam guides
62
.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, it is intended that the following claims cover all modifications and alternative designs, and all equivalents, that fall within the spirit and scope of this invention.
Claims
- 1. A tape transport system for positioning magnetic tape comprising:a first reel with a first pair of parallel flanges between which tape is held, each flange in the first flange pair having a radius greater than a radial distance covered by tape when the first reel is full of tape; a second reel with a second pair of parallel flanges between which tape is held, each flange in the second flange pair having a radius greater than a radial distance covered by tape when the second reel is full of tape, the second reel aligned with the first reel such that the first flange pair is parallel with the second flange pair; a tape head having a curved tape contact surface, the tape head positioned between the first reel and the second reel such that tape extends from the first reel over the contact surface to the second reel; a tape drive operative to unwind tape from one reel, move the tape past the tape head contact surface, and wind the tape on the other reel; and a cam guide associated with each reel, each cam guide comprising a curved surface over which the magnetic tape travels, each cam guide curved surface positioned between the associated reel tape flange pair based on the amount of tape wound on the associated tape reel, each cam guide curved surface supporting the magnetic tape so that the magnetic tape contacts the tape head contact surface at substantially the same location for any amount of tape wound on the associated tape reel.
- 2. A tape transport system as in claim 1 wherein each cam guide curved surface further moves between the associated reel tape flange pair so that the angle at which the magnetic tape leaves the associated reel when the associated reel is fully wound with magnetic tape is substantially the same as the angle at which the magnetic tape leaves the associated reel when the associated reel is fully unwound.
- 3. A tape transport system as in claim 1 wherein each cam guide curved surface further moves between the associated reel tape flange pair to guide tape near the edges of each flange in a tape direction non-normal with a direction of reel rotation where the tape crosses the flange edges.
- 4. A tape transport system as in claim 1 wherein each cam guide curved surface is operative to move completely out from between the associated reel tape flange pair to facilitate loading the associated tape reel into the tape transport system.
- 5. A cam for guiding magnetic tape out of a tape reel, the magnetic tape having an active side comprising a surface onto which information can be written and from which information can be read, the magnetic tape also having a passive side opposite from the active side, the tape reel comprising two parallel flanges between which the magnetic tape is wound as a cylindrical tape pack, each flange having an outside edge, the cam comprising a curved surface over which travels the magnetic tape passive side, the curved surface fitting between the tape reel flanges, the curved surface guiding tape near the tape pack in a path tangential to the tape pack, the cam curved surface operative to move between the flanges in response to the amount of tape in the tape pack to guide tape near the edges of each flange in a tape direction non-normal with a direction of reel rotation where the tape crosses the flange edges.
- 6. A cam for guiding magnetic tape out of a tape reel as in claim 5 further operative to move the curved surface from between the tape reel flanges to facilitate loading the associated tape reel into the tape transport system.
- 7. A method of guiding tape past a tape head comprising:driving the tape from within a first reel having a first pair of flanges; driving the tape from the first reel past the tape head; driving the tape from the tape head onto a second reel having a second pair of flanges; inserting a first curved surface between the first pair of flanges, the first curved surface guiding tape exiting from within the first reel at a first reel tape angle substantially the same when the first reel is fully wound as the first reel tape angle of tape exiting the first reel when the first reel is fully unwound; and inserting a second curved surface between the second pair of flanges, the second curved surface guiding tape exiting from within the second reel at a second reel tape angle substantially the same when the second reel is fully wound as the second reel tape angle of tape exiting the second reel when the second reel is fully unwound.
- 8. A method of guiding tape past a tape head as in claim 7 wherein the tape head includes a curved contact surface past which the magnetic tape is driven, the method further comprising adjusting each curved surface so that the magnetic tape contacts the tape head contact surface in substantially the same location for any amount of tape wound on each reel.
- 9. A method of guiding tape past a tape head as in claim 7 further comprising adjusting the first curved surface so that the first reel tape angle is an acute angle and adjusting the second curved surface so that the second reel tape angle is an acute angle.
- 10. A method of guiding tape past a tape head as in claim 7 further comprising moving the first curved surface from between the first pair of flanges and moving the second curved surface from between the second pair of flanges to facilitate loading the associated tape reel into the tape transport system.
US Referenced Citations (18)
Foreign Referenced Citations (1)
Number |
Date |
Country |
803808 |
Nov 1958 |
GB |