Apparatus for erasing magnetic records of the spiral scanning type

Claim 2

Apparatus for magnetically recording and reproducing signals on a spiral track on a surface of a magnetic sheet, including a. means for retaining a magnetic sheet in a fixed position; b. a magnetic transducer head; c. means for selectively advancing said head in either of two directions along a spiral track on a surface of a magnetic sheet disposed in said fixed position; d. signal circuit means energizing said head for recording on and reproducing from said magnetic sheet during movement of said head in a first of said two directions; and e. manually operable means for reversing the direction of advance of said head along said spiral track; wherein the improvement comprises f. selectively operable erase means energizing said head with an electric current of magnitude to erase signals recorded on said spiral track during movement of said head in the other of said two directions; g. said head including a first gap-defining core means for tracing a spiral track of predetermined transverse width when said head is energized by said signal circuit means during advance in said first direction on said surface, h. and said head further including a second gap-defining core means for tracing a spiral track coincident with but greater in transverse width than said last-mentioned spiral track when said head is energized by said erase means during advance in said other direction on said surface.

Claim 3

Apparatus as defined in claim 1, wherein said signal circuit means includes means for passing a bias current to said head during recording and said erase means passes an erasing current, higher in value than said bias current, to said head upon operation of said erase means.

Claim 4

Apparatus as defined in claim 1, wherein said erase means passes a direct electric current to said head.

Claim 5

Apparatus as defined in claim 1, wherein said erase means is manually operably; and further including means operating concurrently therewith for short-circuiting said signal circuit means.

Claim 6

Apparatus as defined in claim 1, wherein said head comprises a core having a gap, and wherein said first and second gap-defining core means are respectively first and second opposed gap-defining edges of said core, said second edge being wider than said first edge as measured in a direction transverse to a track traced by said head.

Claim 7

Apparatus for magnetically recording and reproducing signals on a spiral track on a surface of a magnetic sheet, including a. means for retaining a magnetic sheet in a fixed position; b. magnetic transducer head means for recording, reproducing and erasing signals on the sheet; c. means for selectively advancing said head means in either of two directions along a spiral track on a surface of a magnetic sheet disposed in said fixed position; d. signal circuit means energizing said head means for recording on and reproducing from said magnetic sheet during movement of said head in a first of said two directions; and e. manually operable means for reversing the direction of advance of said head means along said spiral track; wherein the improvement comprises f. selectively operable erase means energizing said head means with an electric current of magnitude to erase signals recorded on said spiral track during movement of said head means in the other of said two directions; g. said head means comprising means for tracing a spiral track of predetermined transverse width when energized by said signal circuit means and for tracing a spiral track coincident with but of greAter transverse width than said last-mentioned spiral track when energized by said erase means; h. said head means including i. a support, ii. means mounting said support for rotation about an axis oriented radially with respect to said spiral track, said mounting means positioning said support for contact with the magnetic sheet surface to cause the support to rotate, upon advance of the head means by the advancing means, in a direction determined by the direction of advance of the head means, said mounting means including means limiting rotation of the support at first and second angular positions to which the support rotates upon advance of the head means in said first direction and in said other direction, respectively, iii. first and second cores, respectively defining a first gap and a second gap wider than the first gap, carried on said support and disposed to be respectively juxtaposed with said surface when said support is at said first and second angular positions, such that said first core engages said surface during movement of said head means in said first direction and said second core engages said surface during movement of said head means in said other direction, and iv. connecting means for respectively connecting said first core to said signal circuit means and said second core to said erase means.

Claim 8

Apparatus for magnetically recording and reproducing signals on a spiral track on a surface of a magnetic sheet, including a. means for retaining a magnetic sheet in a fixed position; b. magnetic transducer head means for recording, reproducing and erasing signals on the sheet; c. means for selectively advancing said head means in either of two directions along a spiral track on a surface of a magnetic sheet disposed in said fixed position; d. signal circuit means energizing said head means for recording on and reproducing from said magnetic sheet during movement of said head in a first of said two directions; and e. manually operable means for reversing the direction of advance of said head means along said spiral track; wherein the improvement comprises f. selectively operable erase means energizing said head means with an electric current of magnitude to erase signals recorded on said spiral track during movement of said head means in the other of said two directions; g. said head means comprising means for tracing a spiral track of predetermined transverse width when energized by said signal circuit means and for tracing a spiral track coincident with but of greAter transverse width than said last-mentioned spiral track when energized by said erase means; h. said head means including i. a support, ii. means mounting said support for rotation about an axis oriented radially with respect to said spiral track, said mounting means positioning said support for contact with the magnetic sheet surface to cause the support to rotate, upon advance of the head means by the advancing means, in a direction determined by the direction of advance of the head means, said mounting means including means limiting rotation of the support at first and second angular positions to which the support rotates upon advance of the head means in said first direction and in said other direction, respectively, iii. first and second cores, respectively defining a first gap and a second gap wider than the first gap, carried on said support and disposed to be respectively juxtaposed with said surface when said support is at said first and second angular positions, such that said first core engages said surface during movement of said head means in said first direction and said second core engages said surface during movement of said head means in said other direction, and iv. connecting means for respectively connecting said first core to said signal circuit means and said second core to said erase means.