US 3,947,887 A · Transducer head contour and method of generating same

Abstract

A head assembly for reading and writing data upon the magnetizable surface of passing tape. In its initial form the contour of the head comprises four bearing areas separated by three grooves or depressions. The outboard two of the four bearing areas are defined by a pair of contiguous, arcuate surfaces which blend into ramps which extend from opposing sides of the areas. The inboard pair of bearing surfaces each surround and are flush with the ends of a plurality of magnetic transducers adapted to be inductively coupled to a length of magnetic tape passing over the head surfaces. The inboard bearing surfaces are each formed by a major, centrally-disposed arc with second and third contiguous arcuate surfaces located at both ends of the central arc. The above-described contours are initially formed in the head assembly by grinding according to conventional methods. The contours are then modified by lapping with an abrasive tape having predetermined characteristics in accordance with specified procedure to produce a surface which will maintain the stability of the hydrodynamic bearing existing between the tape and the head, and thus the consistency of the separation therebetween, when the tape is accelerated in a reverse direction. The consistent separation thus achieved assures the detection of information on the tape during periods of reverse acceleration.

Claims13

Dependent claims

The method of forming the working surface of a transducer head assembly for receiving a transported magnetic tape, comprising the steps of:

grinding the working surface to form three depressions extending across the head assembly transverse to the direction of tape travel to define four upstanding bearing areas,
the outer two of said bearing areas each comprising a arcuate surface having a radius of no greater than substantially 0.015 inch substantially tangent to the outer edge of ones of said depressions, a second arcuate surface having a radius of substantially 0.5 inch contiguous with said first arcuate surface, and an elongate ramp-like surface extending from said second arcuate surface;
the inner two of said bearing areas each having core means generally centrally located therein for interacting with magnetized areas on said tape;
the inner two of said bearing areas each comprising a first generally central arcuate surface having a radius of from 0.5 to 0.75 inches, second arcuate surfaces contiguous with said first surface and having radii of substantially from 0.1 to 0.2 inches, and third generally arcuate surfaces contiguous with said second surfaces and having radii of up to 0.015 inch;
abrading said arcuate surfaces of said bearing areas with an elongate web having an abrasive surface and oriented in substantially the same position as a tape to be transported by the steps of:
placing said web under a tension of substantially 90% of the lowest tension to be encountered by said tape during a drive cycle;
i. passing a new length of said web over said bearing surfaces in a forward tape transport direction at approximately 200 ips and in a reverse tape transport direction at approximately 600 ips;
ii. passing a used length of said web over said bearing surfaces in a forward tape transport direction at approximately 200 ips and in a reverse tape transport direction at approximately 600 ips;
iii. repeating step (ii) twice;
and
iv. repeating step (i) once.

8 more elements

The method of forming the working surface of a transducer head assembly for hydrodynamically supporting a transported magnetic tape thereon, comprising the steps of:

grinding the working surface to form at least three depressions extending transverse to the direction of tape travel and defining four upstanding bearing areas;
the outer two of said bearing areas each terminating at the inner end thereof in an edge having a radius of no more than 0.015 inch, terminating at the outer edge thereof in an elongate ramp-like surface, and having intermediate said ends an arcuate surface having a radius of approximately 1/2 inch;
the inner two of said bearing areas each being adapted to receive a plurality of core means for interacting with magnetized areas upon length of tape transported over said bearing areas;
the inner two of said bearing areas each terminating in edges having radii of no more than 0.015 inch, having a central, arcuate surface generated by a radius of from substantially 0.5 to 0.75 inches and a pair of lesser arcuate surfaces disposed at either end of said central arcuate surface having radii of substantially from 0.1 to 0.2 inches;
abrading said bearing areas with a length of abrasive tape oriented in substantially the same position as a magnetic tape to be transported, by sequentially subjecting the ground working surface to a single pass of new tape, three passes of used tape, and another single pass of new tape;
and
each of said passes comprising transporting a length of approximately 1500 to 2000 feet of said abrasive tape over said working surface at approximately 200 ips in a forward tape transport direction, and at approximately 600 ips in a reverse transport tape direction.

4 more elements

Dependencies are inferred from the claim text.

Transducer head contour and method of generating same

Life of this patent

Transducer head contour and method of generating same

Life of this patent

Abstract

Claims13