Helical read/write head having a cross-cut groove

• US 5,289,330 A
• Filed: 10/02/1991
• Issued: 02/22/1994
• Est. Priority Date: 10/02/1991
• Status: Expired due to Fees

• Current Assignee: Sypris Data Systems Incorporated (Sypris Solutions Incorporated)
• Original Assignee: Alliant Techsystems Incorporated (Northrop Grumman Corporation)
• Inventors: Wade, Gerald J.
• Primary Examiner(s): Westin, Edward P.
• Assistant Examiner(s): Driscoll, Benjamin D.
• Application Number:
  US07/771,043
• Time in Patent Office: 874 Days
• Field of Search: 360/122, 360/84, 360/107
• US Class Current: 360/122
• CPC Class Codes: G11B 15/61 on drum, e.g. drum containing rotating heads G11B15/66 takes precedence
• CPC Class Codes: G11B 15/64 by fluid-dynamic spacing
• CPC Class Codes: G11B 5/53 Disposition or mounting of heads on rotating support

Abstract

An improved helical read/write head is disclosed having a cross-cut groove disposed on the lead sloping surface thereof to improve reliability. The cross-cut groove is positioned between the magnetic gap of the helica head and an initial head/tape interface region of the head and is preferably oriented perpendicular to the longitudinal axis/direction of travel of the tape. The cross-cut groove may be particularly positioned to accommodate and dampen tape disruption attendant to initiating the helical head/tape interface.

Claims

1. In a helical scan data storage system having at least one helical head rotating in a first plane and a magnetic tape driven relative to said at least one rotating helical head and positioned to repeatedly and operatively interface with a face of said at least one rotating helical head at an acute angle relative to said first plane, at least a first improved helical head comprising:

a magnetic gap disposed across the face of said first helical head for magnetically interfacing with said magnetic tape;

a lead sloping surface on one side of said magnetic gap on said face, and having an initial interface region that initially and repeatedly interfaces with said magnetic tape;

a groove laterally disposed across said lead sloping surface between said initial interface region of said lead sloping surface and said magnetic gap so as to inwardly draw and receive, and thereby dynamically dampen, magnetic tape disruption approximating a standing wave attendant to said initial and repeated interface between said initial interface region of said lead sloping surface and said magnetic tape, wherein an edge of said groove nearest to said magnetic gap is positioned between appproximately 100μ

m and 400μ

m from the magnetic gap, the width of said groove is between approximately 100μ

m and 40μ

m, and the depth of said groove is between approximately 20μ

m and 100μ

m.

2. In a helical scan data storage system, at least a first improved helical head as claimed in claim 1, wherein said groove is positioned substantially perpendicular to the longitudinal axis of said magnetic tape.

3. In a helical scan data storage system, at least a first improved helical head as claimed in claim 1, wherein said groove is disposed to receive at least one selected half-period of said approximate standing wave.

4. In a helical scan data storage system, at least a first improved helical head as claimed in claim 1, wherein the width and positioning of said groove is selected so that the edges of the groove substantially coincide with the nodes of said approximate standing wave defining said at least one selected half-period.

5. In a helical scan data storage system, at least a first improved helical head as claimed in claim 1, wherein the depth of said groove is selected to receive the peak amplitude of said at least one selected half-period of said approximate standing wave.

6. In a helical scan data storage system, at least a first improved helical head as claimed in claim 1, said first improved helical head further comprising:

a trailing surface disposed on another side of said magnetic gap on said face and sloping away from said magnetic gap; and

a groove laterally disposed across said trailing surface of said helical head.

7. In a helical scan data storage system, at least a first improved helical head as claimed in claim 1, wherein said first improved head is provided to write onto said magnetic tape, and further comprising a second improved helical head juxtaposed to said first improved helical head and provided to read from said magnetic tape, said second improved helical head comprising:

a magnetic gap disposed across a face of said second helical head for magnetically interfacing with said magnetic tape during use;

a sloping surface on one side of said magnetic gap on said face of said second improved helical head; and

a groove laterally disposed across said sloping surface on said second helical head.

8. A helical head for use in a helical scan data storage system, comprising:

a magnetic gap disposed across a face of said helical head for magnetically interfacing with a magnetic tape during use;

a lead sloping surface disposed on one side of said magnetic gap and having an initial interface region for initially and repeatedly interfacing with said magnetic tape during use;

a cross-cut groove laterally disposed at a selected location across said lead sloping surface between said magnetic gap and said initial interface region so as to draw inwardly, and thereby dynamically dampen, magnetic tape disruption attendent to said initial and repeated interface between said initial interface region of said lead sloping surface and said magnetic tape, wherein an edge of said cross-cut groove nearest to said magnetic gap is positioned between approximately 100μ

m and 400μ

m from the magnetic gap, the width of said groove is between approximately 100μ

m and 40μ

m, and the depth of said groove is between approximately 20μ

m and 100μ

m.

9. A helical head as claimed in claim 8, said cross-cut groove having a selected width, wherein said selected location and said selected width are established to receive at least one selected half-period of any tape disruption approximating a standing wave attendant to said initial interface of said initial interface region of said lead sloping surface and said magnetic tape.

10. A helical head as claimed in claim 8, said cross-cut groove having a selected depth, wherein said selected location and said selected width are established to receive at least one selected half-period of any tape disruption approximating a standing wave attendant to said initial interface of said initial interface region of said lead sloping surface and said magnetic tape.

11. A helical head as claimed in claim 8, wherein said cross-cut groove is disposed substantially perpendicular to the longitudinal axis of said magnetic tape.

12. A helical head as claimed in claim 8, further comprising:

a trailing surface disposed on the other side of said magnetic gap on said face; and

a groove disposed across said trailing surface of said helical head.

13. A helical head as claimed in claim 8, said cross-cut groove having a selected width, wherein said selected location and said selected width are established to substantially avoid influencing said magnetic interface between said magnetic gap and said magnetic tape during use.

14. A helical head as claimed in claim 8, said cross-cut groove having a selected width and depth, wherein said selected location, width and depth are established to maintain sufficient core material between said cross-cut groove and a window in said helical head for magnetic flux passage therethrough during use.