Patent ID: 6151191
Filing Date: 2000-11-21
Classification: G11B

Abstract:
A helical scan head assembly for use with magnetic tape that is wrapped helically around a rotating drum of said head assembly, and moves, relative to a stationary reference in the same direction that said drum is rotating, but at a slower speed, so that, from the perspective of the rotating drum, the tape is observed to be moving along a circumferential machine dimension from an upstream direction to a downstream direction, said head assembly comprising:a. a first circular cylindrical drum that is rotatable around an axis;b. fixed to said rotatable drum, a head, having a signal exchange surface that comprises:i. a signal exchange site;ii. an upstream corner upstream of said signal exchange site; andiii an upstream signal exchange surface, defined by an upstream main signal exchange surface curve, located along said machine dimension between said upstream corner and said signal exchange site, which signal exchange surface meets said upstream corner at a main slope discontinuity and has an upstream main tangent .tau..sub.main at said main slope discontinuity; andsaid head being located at a radial position and said upstream corner being sufficiently sharp and said upstream main tangent being such that, if any said tape is wrapped helically around said drum and contacts said head and said drum is rotating relative to said tape, then;i. an upstream portion of said tape contacts said upstream corner;ii. a portion of said tape that is downstream and adjacent to said upstream corner contacting portion, is spaced away from said signal exchange surface adjacent to and downstream from said main slope discontinuity, forming a hollow bump between said tape and said signal exchange surface; andiii. a portion of said tape downstream from and adjacent said hollow bump contacts said signal exchange surface along the full extent from said bump to and including said signal exchange site.