US4656548A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tape cassette containing echo-erasing means
Assignee: BASF SE
•
Filing: 1983-11-22
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Granted: 1987-04-07
•
Expires: 2003-11-22
Abstract
Abstract A tape cassette comprising at least one print-through echo-erasing device in the form of at least one appropriately shaped magnetic member made of permanent magnet material which is conveniently arranged on a tape guide element or near the apertures in the front wall of the cassette housing for the admission of scanning means. Such echo-erasing device can be used with advantage in any kind of magnetic tape cassette or cassette containing a recording medium having at least one magnetic track.
Inventors
- 👤 Dietmar Pfefferkorn
- 👤 Gerhard Nerschbach
- 👤 Eberhard Koester
- 👤 Norbert Kreimes
- 👤 Bozidar Pavelka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:10
CPC Classifications
G; G11; G11B; G11B23/00; G11B23/02; G11B23/04
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
141 words
A tape cassette having a housing containing therein a magnetic recording medium in the form of two coplanar tape rolls having at least one magnetic track, said cassette comprising print-through echo-erasing means within said housing in the path of travel of the magnetic medium, said housing having a front wall, with openings through which the recording medium is accessed during the recording and/or playback operation, and said echo-erasing means consisting of two magnetic members made of permanent magnet material having a coercive force H c in the range from 50 kA/m to 400 kA/m and having a constant field strength in the range from 4 kA/m to 32 kA/m on the portion of the periphery of the member which faces the recording medium, said two magnetic members being disposed symmetrically with respect to the central transverse axis of the cassette housing.
Claim 2
Dependent Claim
141 words
A tape cassette having a housing containing therein a magnetic recording medium in the form of two coplanar tape rolls having at least one magnetic track, said cassette comprising print-through echo-erasing means within said housing in the path of travel of the magnetic medium, said housing having a front wall, with openings through which the recording medium is accessed during the recording and/or playback operation, and said echo-erasing means consisting of two magnetic members made of permanent magnet material having a coercive force H c in the range from 50 kA/m to 400 kA/m and having a constant field strength in the range from 4 kA/m to 32 kA/m on the portion of the periphery of the member which faces the recording medium, said two magnetic members being disposed symmetrically with respect to the central transverse axis of the cassette housing.
Claim 3
Dependent Claim
26 words
A tape cassette as claimed in claim 1, wherein the magnetic members consist of a barium ferrite and have a coercive force of about 400 kA/m.
Claim 4
Dependent Claim
22 words
A tape cassette as claimed in claim 1, wherein the magnetic members consist of ferrite material of the Me 2 Y type.
Claim 5
Dependent Claim
22 words
A tape cassette as claimed in claim 1, wherein the magnetic members consist of a cobalt/rare earth alloy, especially a cobalt/samarium alloy.
Claim 6
Dependent Claim
24 words
A tape cassette as claimed in claim 1, wherein the magnetic members consist of a plastic material and particulate permanent magnet material dispersed therein.
Claim 7
Dependent Claim
26 words
A tape cassette as claimed in claim 1, wherein the magnetic members are arranged in the corner of the cassette housing, facing the tape guide roller.
Claim 8
Dependent Claim
26 words
A tape cassette as claimed in claim 1, wherein the magnetic members are in the form of tape guide rollers and are in particular magnetized radially.
Claim 9
Dependent Claim
44 words
A tape cassette as claimed in claim 1, wherein the magnetic members have a field strength of about 24 to 32 kA/m on the portion of their periphery which faces the recording medium, the distance between said portion and the medium being 2 mm.
Claim 10
Dependent Claim
47 words
A tape cassette as claimed in claim 1, wherein the magnetic members have a field strength of about 4 to 13 kA/m on the portion of their periphery which faces the recording medium, the distance between said portion and the medium being not more than 2 mm.
Claim 11
Dependent Claim
25 words
A tape cassette as claimed in claim 1, wherein the magnetic members consist of barium ferrite and are provided on two tape guide elements, respectively.
Claim 12
Dependent Claim
57 words
A tape cassette as claimed in claim 1, wherein said housing has a compartment accommodating said rolls, and a partition separating said compartment from the openings in the front wall, and wherein said magnetic members are arranged symmetrically with respect to the central transverse axis of the cassette housing at least in the vicinity of said partition.
Claim 13
Dependent Claim
47 words
A tape cassette as claimed in claim 1, wherein the permanent magnet material has a coercive force H c of about 400 kA/m and exerts a minimum field strength of 4 kA/m on the portion of the periphery of the magnetic member which faces the recording medium.
Claim 14
Dependent Claim
21 words
A tape cassette as claimed in claim 1, wherein the magnetic members are arranged on movably mounted strip-shaped tape guide elements.
Claim 15
Dependent Claim
35 words
A tape cassette as claimed in claim 13, wherein the magnetic members are arranged on the same side of the tape guide element as that on which said element, near its end, supports the tape.
Claim 16
Dependent Claim
40 words
A tape cassette as claimed in claim 13, wherein the magnetic members are cylindrical in shape and are arranged on the same side of the tape guide element as that on which said element, near its end, supports the tape.
References Cited (Backward Citations)
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Cited
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US3351717A
Cited
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JPS529404A
Cited
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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) | 1990-04-06 | 1990-10-06 | 1991-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-06 | 1994-10-06 | 1995-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-06 | 1998-10-06 | 1999-04-07 | $7700.00 | Window Closed / Lapsed |