Magnetic transducer head with auxiliary means for diverting residual flux

Claim 2

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the record medium, said auxiliary means being essentially disconnected from the material forming said magnetic core so as to accommodate relative thermal expansion therebetween.

Claim 3

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the record medium, a relatively wide sheet of magnetic material having a first portion of the width thereof defining said magnetic core and having a second portion of the width thereof defining said auxiliary means, said second portion of said sheet being joined with said first portion by means of a bend to offset said second portion from the Level of the first portion.

Claim 4

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the record medium, a relatively wide sheet of magnetic material having a first portion of the width thereof defining said magnetic core and having a second portion of the width thereof defining said auxiliary means, said second portion of said sheet being joined with said first portion by means of a bend to offset said second portion from the Level of the first portion.

Claim 5

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the record medium, said magnetic core having a signal flux path therein and the material of said magnetic core being oriented generally at right angles to said signal flux path.

Claim 6

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the record medium, said magnetic core having a signal flux path therein and the material of said magnetic core being oriented generally at right angles to said signal flux path.

Claim 7

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the record medium, a keeper housing containing said core and said auxiliary means and having a top surface adjacent the record medium path, mounting means for holding the core, and fastening means at the top surface of the housing securing the housing to the mounting means and exerting fastening force generally normal to the top surface of the housing

Claim 8

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the record medium, a keeper housing containing said core and said auxiliary means and having a top surface adjacent the record medium path, mounting means for holding the core, and fastening means at the top surface of the housing securing the housing to the mounting means and exerting fastening force generally normal to the top surface of the housing

Claim 9

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the record medium, said auxiliary means being a separate piece of material from said magnetic core and having a magnetic length substantially less than said magnetic core and a cross section substantially greater than that of said core.

Claim 10

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the record medium, said auxiliary means being a separate piece of material from said magnetic core and having a magnetic length substantially less than said magnetic core and a cross section substantially greater than that of said core.

Claim 11

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the redium, said auxiliary means being in a substantially unstressed condition, said magnetic core having a signal flux path therein and having a cross-sectional configuration transverse to said signal flux path with an interior space, and said auxiliary means comprising auxiliary magnetic material disposed within said interior space of said magnetic core, the material of said magnetic core extending on three sides of the auxiliary magnetic material within said interior space.

Claim 12

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the redium, said auxiliary means being in a substantially unstressed condition, said magnetic core having a signal flux path therein and having a cross-sectional configuration transverse to said signal flux path with an interior space, and said auxiliary means comprising auxiliary magnetic material disposed within said interior space of said magnetic core, the material of said magnetic core extending on three sides of the auxiliary magnetic material within said interior space.

Claim 13

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the record medium, said auxiliary means being in a substantially unstressed condition, said auxiliary means in its entirety being spaced from the record medium path so as to be clear of contact with the magnetic record medium, said magnetic core having confronting poles with upper record contacting surfaces for sliding engagement with the record medium, the coupling means comprising a nonmagnetic gap between the poles, and the poles having under surfaces opposite the upper record contacting surfaces thereof, and said auxiliary means comprising auxiliary material extending along the under surfaces of the poles and having a substantially greater thickness dimension than the thickness dimension of the poles between the under surfaces and the upper record contacting surfaces thereof.

Claim 14

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the record medium, said auxiliary means being in a substantially unstressed condition, said auxiliary means in its entirety being spaced from the record medium path so as to be clear of contact with the magnetic record medium, said magnetic core having confronting poles with upper record contacting surfaces for sliding engagement with the record medium, the coupling means comprising a nonmagnetic gap between the poles, and the poles having under surfaces opposite the upper record contacting surfaces thereof, and said auxiliary means comprising auxiliary material extending along the under surfaces of the poles and having a substantially greater thickness dimension than the thickness dimension of the poles between the under surfaces and the upper record contacting surfaces thereof.

Claim 15

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the record medium, said auxiliary means being in a substantially unstressed condition, said auxiliaRy means being formed in the same magnetic material and integral with said magnetic core and said magnetic core having adequate flux carrying capacity for efficient recording operation without said auxiliary means, and said auxiliary means having a cross section substantially greater than the cross section of said magnetic core and serving to reduce the field due to residual magnetization of said magnetic core which intersects the record medium path to a value substantially below the coercivity of the record medium.

Claim 16

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the record medium, said auxiliary means being in a substantially unstressed condition, said auxiliaRy means being formed in the same magnetic material and integral with said magnetic core and said magnetic core having adequate flux carrying capacity for efficient recording operation without said auxiliary means, and said auxiliary means having a cross section substantially greater than the cross section of said magnetic core and serving to reduce the field due to residual magnetization of said magnetic core which intersects the record medium path to a value substantially below the coercivity of the record medium.

Claim 17

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the record medium, said auxiliary means being in a substantially unstressed condition, said auxiliary means reducing the residual flux which intersects the record medium path by at least 50 percent in comparison with the case where the auxiliary means is omitted, said magnetic core having confronting poles with upper record contacting surfaces for sliding engagement with the record medium, the coupling means comprising a nonmagnetic gap between the poles, and the poles having under surfaces opposite the upper record contacting surfaces thereof, and said auxiliary means comprising auxiliary material extending along the under surfaces of the poles and having a substantially greater thickness dimension than the thickness dimension of the poles between the under surfaces and the upper record contacting surfaces thereof, said auxiliary material being within a distance of not greater than about 0.001 inch of said magnetic core, but being entirely clear of the region between said poles.

Claim 18

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the record medium, said auxiliary means being in a substantially unstressed condition, said auxiliary means reducing the residual flux which intersects the record medium path by at least 50 percent in comparison with the case where the auxiliary means is omitted, said magnetic core having confronting poles with upper record contacting surfaces for sliding engagement with the record medium, the coupling means comprising a nonmagnetic gap between the poles, and the poles having under surfaces opposite the upper record contacting surfaces thereof, and said auxiliary means comprising auxiliary material extending along the under surfaces of the poles and having a substantially greater thickness dimension than the thickness dimension of the poles between the under surfaces and the upper record contacting surfaces thereof, said auxiliary material being within a distance of not greater than about 0.001 inch of said magnetic core, but being entirely clear of the region between said poles.

Claim 19

A magnetic head for coupling to a track on a magnetic record medium and having a predetermined scanning width corresponding to the width of said track, said head comprising a magnetic core having coupling means for coupling the magnetic core to said track as the record medium travels along a record medium path across said core, a relatively wide sheet of magnetic material having a first portion of the width thereof forming said magnetic core and having a second portion of the width of said sheet substantially increasing the flux carrying capacity of the head without increasing the scanning width thereof, said first portion of the width of said sheet having a width dimension defining the scanning width of the head, and auxiliary means comprising said second portion of said sheet and providing magnetic material having a coercivity substantially lower than the coercivity of the magnetic core for diverting residual flux due to residual magnetization of the magnetic core from the path of the record medium.

Claim 20

A magnetic head for coupling to a track on a magnetic record medium and having a predetermined scanning width corresponding to the width of said track, said head comprising a magnetic core having coupling means for coupling the magnetic core to said track as the record medium travels along a record medium path across said core, a relatively wide sheet of magnetic material having a first portion of the width thereof forming said magnetic core and having a second portion of the width of said sheet substantially increasing the flux carrying capacity of the head without increasing the scanning width thereof, said first portion of the width of said sheet having a width dimension defining the scanning width of the head, and auxiliary means comprising said second portion of said sheet and providing magnetic material having a coercivity substantially lower than the coercivity of the magnetic core for diverting residual flux due to residual magnetization of the magnetic core from the path of the record medium.

Claim 21

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means of magnetic material disposed adjacent said magnetic core and being in a relatively unstressed condition, said magnetic core comprising a core portion adjacent said coupling means and across which the record medium travels, and said auxiliary means comprising an integral lateral extension of said core portion and extending on the side of said core portion remote from the record medium path.

Claim 22

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means of magnetic material disposed adjacent said magnetic core and being in a relatively unstressed condition, said magnetic core comprising a core portion adjacent said coupling means and across which the record medium travels, and said auxiliary means comprising an integral lateral extension of said core portion and extending on the side of said core portion remote from the record medium path.

Claim 23

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means of magnetic material disposed adjacent said magnetic core and being in a relatively unstressed condition, said magnetic core having a generally channel cross section to define a pocket on the side of the core remote from the record medium path, and said auxiliary means comprising separate pieces of magnetic material disposed inside said pocket.

Claim 24

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means of magnetic material disposed adjacent said magnetic core and being in a relatively unstressed condition, said magnetic core having a generally channel cross section to define a pocket on the side of the core remote from the record medium path, and said auxiliary means comprising separate pieces of magnetic material disposed inside said pocket.

Claim 25

A magnetic head for coupling to a magnetic record medium comprising a magnetic core having a plurality of individual core parts of sheet magnetic material defining a magnetic circuit having a region for coupling to a magnetic record medium, at least one of said core parts having a body portion with a width dimension between opposite side margins extending generally transversely to the path of magnetic flux through said one of said core parts and having an integral angularly related portion extending at a substantial angle from at least one side margin of said body portion for increasing the cross-sectional area of the portion of the magnetic circuit defined by said one of said core parts without a corresponding increase in the width dimension of the core part.

Claim 26

A magnetic head for coupling to a magnetic record medium comprising a magnetic core having a plurality of individual core parts of sheet magnetic material defining a magnetic circuit having a region for coupling to a magnetic record medium, at least one of said core parts having a body portion with a width dimension between opposite side margins extending generally transversely to the path of magnetic flux through said one of said core parts and having an integral angularly related portion extending at a substantial angle from at least one side margin of said body portion for increasing the cross-sectional area of the portion of the magnetic circuit defined by said one of said core parts without a corresponding increase in the width dimension of the core part.

Claim 27

A magnetic head for coupling to a magnetic record medium comprising a magnetic core having a plurality of core parts of sheet magnetic material defining a magnetic circuit having a region for coupling to a magnetic record medium, said core parts having a channel section transverse to the flux path through said parts throughout a substantial portion of the length thereof.

Claim 28

A magnetic head for coupling to a magnetic record medium comprising a magnetic core having a plurality of core parts of sheet magnetic material defining a magnetic circuit having a region for coupling to a magnetic record medium, said core parts having a channel section transverse to the flux path through said parts throughout a substantial portion of the length thereof.

Claim 29

A magnetic head for coupling to a magnetic record medium comprising a magnetic core having a plurality of core parts of sheet magnetic material defining a magnetic circuit having a region for coupling to a magnetic record medium, said core parts having a channel cross section transverse to the flux path through said parts throughout a substantial portion of the length thereof but having a rectangular cross section adjacent said region for coupling to the record medium to provide reduced cross section pole portions.

Claim 30

A magnetic head for coupling to a magnetic record medium comprising a magnetic core having a plurality of core parts of sheet magnetic material defining a magnetic circuit having a region for coupling to a magnetic record medium, said core parts having a channel cross section transverse to the flux path through said parts throughout a substantial portion of the length thereof but having a rectangular cross section adjacent said region for coupling to the record medium to provide reduced cross section pole portions.

Claim 31

A magnetic head comprising a magnetic core having a signal flux path therein of loop configuration and having coupling means for coupling the signal flux path of the magnetic core to a magnetic record medium traveling along a record medium path, auxiliary means of magnetic material disposed adjacent said magnetic core and being in a relatively unstressed condition as finally assembled, said magnetic core having an elongated side face thereof which defines a boundary of the signal flux path in said magnetic core and said elongated side face extending over substantially the entire length of said signal flux path in said magnetic core, said auxiliary means comprising separate auxiliary magnetic material formed entirely separately from the magnetic core and said separate auxiliary magnetic material having an elongated surface thereof disposed in confronting relation to said elongated side face of said magnetic core material over substantially the entire length of said elongated side face, said auxiliary magnetic material having a substantial cross-sectional area in comparison to the cross-sectional area of said magnetic core so as to provide substantial additional flux carrying capacity parallel to said signal flux path, and an electric winding encircling in common the signal flux path of said magnetic core and said separate auxiliary magnetic material.

Claim 32

A magnetic head comprising a magnetic core having a signal flux path therein of loop configuration and having coupling means for coupling the signal flux path of the magnetic core to a magnetic record medium traveling along a record medium path, auxiliary means of magnetic material disposed adjacent said magnetic core and being in a relatively unstressed condition as finally assembled, said magnetic core having an elongated side face thereof which defines a boundary of the signal flux path in said magnetic core and said elongated side face extending over substantially the entire length of said signal flux path in said magnetic core, said auxiliary means comprising separate auxiliary magnetic material formed entirely separately from the magnetic core and said separate auxiliary magnetic material having an elongated surface thereof disposed in confronting relation to said elongated side face of said magnetic core material over substantially the entire length of said elongated side face, said auxiliary magnetic material having a substantial cross-sectional area in comparison to the cross-sectional area of said magnetic core so as to provide substantial additional flux carrying capacity parallel to said signal flux path, and an electric winding encircling in common the signal flux path of said magnetic core and said separate auxiliary magnetic material.

Claim 33

A magnetic head having a pair of poles, means providing a path for a magnetic record medium successively across said poles, one of said poles being disposed directly at the record medium path and the other of said poles being substantially offset from said record medium path and a nonmagnetic material interposed between the other of said poles and said record medium and having a thickness dimension of the order of 0.0005 inch.

Claim 34

A magnetic head having a pair of poles, means providing a path for a magnetic record medium successively across said poles, one of said poles being disposed directly at the record medium path and the other of said poles being substantially offset from said record medium path and a nonmagnetic material interposed between the other of said poles and said record medium and having a thickness dimension of the order of 0.0005 inch.

Claim 35

The head of claim 17 with said nonmagnetic material being plated on said other of said poles.

Claim 36

A magnetic head having a pair of poles, means providing a path for a magnetic record medium successively across said poles, one of said poles being disposed directly at the record medium path and the other of said poles being substantially offset from said record medium path, and the other of the poles being offset from the record medium path by a distance in the range from about 0.001 inch to 0.00002 inch.

Claim 37

A magnetic head having a pair of poles, means providing a path for a magnetic record medium successively across said poles, one of said poles being disposed directly at the record medium path and the other of said poles being substantially offset from said record medium path, and the other of the poles being offset from the record medium path by a distance in the range from about 0.001 inch to 0.00002 inch.

Claim 38

The head of claim 19 with said other pole having a spacer of chrOmium plated thereon to provide said offset, with said record medium being in sliding contact with said spacer as it travels along said record medium path.

Claim 39

A magnetic head comprising a magnetic core having a signal flux path therein of loop configuration and having coupling means for coupling the signal flux path of the magnetic core to a magnetic record medium traveling along a record medium path, auxiliary means of magnetic material disposed adjacent said magnetic core and being in a relatively unstressed condition as finally assembled, said magnetic core having an elongated side face thereof which defines a boundary of the signal flux path in said magnetic core and said elongated side face extending over substantially the entire length of said signal flux path in said magnetic core, said auxiliary means comprising auxiliary magnetic material having an elongated surface thereof disposed in confronting relation to said elongated side face of said magnetic core over substantially the entire length of said face, said auxiliary means in its entirety being spaced from the record medium path so as to be clear of contact with the magnetic record medium and having a cross-sectional area at least approximately equal to the cross-sectional area of said magnetic core to add substantially to the flux carrying capacity of the magnetic core without substantially increasing the scanning width of the magnetic head, and an electric winding encircling in common the signal flux path of said magnetic core and said auxiliary magnetic material.

Claim 40

A magnetic head comprising a magnetic core having a signal flux path therein of loop configuration and having coupling means for coupling the signal flux path of the magnetic core to a magnetic record medium traveling along a record medium path, auxiliary means of magnetic material disposed adjacent said magnetic core and being in a relatively unstressed condition as finally assembled, said magnetic core having an elongated side face thereof which defines a boundary of the signal flux path in said magnetic core and said elongated side face extending over substantially the entire length of said signal flux path in said magnetic core, said auxiliary means comprising auxiliary magnetic material having an elongated surface thereof disposed in confronting relation to said elongated side face of said magnetic core over substantially the entire length of said face, said auxiliary means in its entirety being spaced from the record medium path so as to be clear of contact with the magnetic record medium and having a cross-sectional area at least approximately equal to the cross-sectional area of said magnetic core to add substantially to the flux carrying capacity of the magnetic core without substantially increasing the scanning width of the magnetic head, and an electric winding encircling in common the signal flux path of said magnetic core and said auxiliary magnetic material.

Claim 41

A magnetic head according to claim 21 with the magnetic core being formed of magnetic material which is in an unstressed condition compared to laminations which are glued and clamped after anneal.

Claim 42

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means of magnetic material disposed adjacent said magnetic core and being in a relatively unstressed condition, said magnetic core having magnetic core material defining a loop magnetic flux path for coupling with the magnetic record medium at said coupling means, said magnetic core material providing at an outer side of the loop magnetic flux path an outer elongated side face which slidably engages with the magnetic record medium adjacent said coupling means, and providing at an inner side of the loop magnetic flux path opposite said outer side an inner elongated side face, said auxiliary means of magnetic material comprising auxiliary magnetic material of sheet configuration disposed substantially at right angles to said inner elongated side face of said magnetic core and extending along said inner elongated side face over substantially the entire length thereof, said auxiliary magnetic material having a cross section at least substantially equal to the cross section of said magnetic core material, said auxiliary means in its entirety being spaced from the record medium path so as to be clear of contact with the magnetic record medium, said auxiliary magnetic material serving to substantially add to the flux carrying capacity of the magnetic core without increasing the scanning width of the magnetic head, and an electric signal winding coupled in common to said signal flux path of said magnetic core material and said auxiliary magnetic material.

Claim 43

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means of magnetic material disposed adjacent said magnetic core and being in a relatively unstressed condition, said magnetic core having magnetic core material defining a loop magnetic flux path for coupling with the magnetic record medium at said coupling means, said magnetic core material providing at an outer side of the loop magnetic flux path an outer elongated side face which slidably engages with the magnetic record medium adjacent said coupling means, and providing at an inner side of the loop magnetic flux path opposite said outer side an inner elongated side face, said auxiliary means of magnetic material comprising auxiliary magnetic material of sheet configuration disposed substantially at right angles to said inner elongated side face of said magnetic core and extending along said inner elongated side face over substantially the entire length thereof, said auxiliary magnetic material having a cross section at least substantially equal to the cross section of said magnetic core material, said auxiliary means in its entirety being spaced from the record medium path so as to be clear of contact with the magnetic record medium, said auxiliary magnetic material serving to substantially add to the flux carrying capacity of the magnetic core without increasing the scanning width of the magnetic head, and an electric signal winding coupled in common to said signal flux path of said magnetic core material and said auxiliary magnetic material.

Claim 44

A magnetic head in accordance with claim 23 with said magnetic core material being in an unstressed condition compared to laminations which are glued and clamped after anneal.

Claim 45

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the record medium, mounting means secured to said magnetic core for fixedly positioning the same relative to said record mediUm path during a transducing operation, and said mounting means being spaced from said auxiliary means by a nonrigid medium so as to avoid stressing of the material of said auxiliary means.

Claim 46

A magnetic head comprising a magnetic core having coupling means for coupling the core to a magnetic record medium traveling along a record medium path, and auxiliary means disposed adjacent said magnetic core for diverting residual flux due to residual magnetization of the core from the path of the record medium, mounting means secured to said magnetic core for fixedly positioning the same relative to said record mediUm path during a transducing operation, and said mounting means being spaced from said auxiliary means by a nonrigid medium so as to avoid stressing of the material of said auxiliary means.

Claim 47

The head of claim 25 with said auxiliary material being integral with said magnetic core, and the space between said auxiliary means and said mounting means being filled with a yieldable material.

Claim 48

The head of claim 25 with said auxiliary means being separated from said magnetic core by a layer of nonrigid medium.

Claim 49

The head of claim 27 with said auxiliary means being spot welded to said core at the part thereof near said coupling means.

Claim 50

The head of claim 27 with said layer having a thickness dimension of not greater than about 0.001 inch over at least a substantial proportion of the area thereof.

Claim 51

A magnetic head comprising a magnetic core having a coupling gap for coupling of the core with a magnetic record medium moving along a record medium path across the core, said magnetic core being formed of relatively wide sheet material, said sheet material having confronting free end portions of reduced width at opposite sides of said coupling gap, said sheet material providing a loop magnetic flux path between said free end portions for magnetic flux interlinkage with the record medium at said coupling gap, said free end portions having a width dimension extending along the transverse boundaries of said coupling gap corresponding to the width of the channel of the record medium to which said magnetic core is coupled, said sheet material providing a main magnetic core portion extending along said loop magnetic flux path and having a width equal to the width dimension of said free end portions, said sheet material providing an auxiliary magnetic core portion for diverting residual flux due to residual magnetization of the core from the path of the record medium, and extending laterally from the main core portion to provide a total width of said sheet material transverse to said loop magnetic flux path except at said free end portions which total width is substantially greater than the width dimension of said free end portions at the transverse boundaries of said coupling gap, said auxiliary magnetic core portion being spaced from the record medium path over its entire extent so as to be clear of contact with the record medium, and auxiliary means comprising said auxiliary magnetic core portion for reducing the field intersecting the record medium path due to a maximum residual magnetization of the magnetic core to a value substantially below the coercivity of the record medium.

Claim 52

A magnetic head comprising a magnetic core having a coupling gap for coupling of the core with a magnetic record medium moving along a record medium path across the core, said magnetic core being formed of relatively wide sheet material, said sheet material having confronting free end portions of reduced width at opposite sides of said coupling gap, said sheet material providing a loop magnetic flux path between said free end portions for magnetic flux interlinkage with the record medium at said coupling gap, said free end portions having a width dimension extending along the transverse boundaries of said coupling gap corresponding to the width of the channel of the record medium to which said magnetic core is coupled, said sheet material providing a main magnetic core portion extending along said loop magnetic flux path and having a width equal to the width dimension of said free end portions, said sheet material providing an auxiliary magnetic core portion for diverting residual flux due to residual magnetization of the core from the path of the record medium, and extending laterally from the main core portion to provide a total width of said sheet material transverse to said loop magnetic flux path except at said free end portions which total width is substantially greater than the width dimension of said free end portions at the transverse boundaries of said coupling gap, said auxiliary magnetic core portion being spaced from the record medium path over its entire extent so as to be clear of contact with the record medium, and auxiliary means comprising said auxiliary magnetic core portion for reducing the field intersecting the record medium path due to a maximum residual magnetization of the magnetic core to a value substantially below the coercivity of the record medium.

Claim 53

A magnetic transducer head according to claim 30 with said auxiliary magnetic core portion of the width of said sheet material having a lateral dimension at least substantially equal to the width dimension of said main magnetic core portion so that the total width of said sheet material is at least substantially twice the width dimension of said main magnetic core portion.

Claim 54

A magnetic transducer head according to claim 30 with said auxiliary magnetic core portion of the width of said sheet material providing a residual magnetic flux path for residual flux produced by residual magnetization of said main core portion bypassing said record medium and serving to reduce the residual flux intersecting the record medium path by at least about 50 percent compared with a head consisting of said main magnetic core portion only.

Claim 55

A magnetic transducer head according to claim 30 with said auxiliary magnetic core portion of said sheet material having a cross section substantially greater than that of said main magnetic core portion of said sheet material.

Claim 56

A magnetic transducer head according to claim 30 with said auxiliary means being further provided by auxiliary magnetic material disposed adjacent to but insulated from said sheet material on the side thereof away from said record medium pAth.

Claim 57

A magnetic transducer head according to claim 34 with said auxiliary magnetic material having a coercivity as measured from direct current saturation not substantially greater than from 0.003 oersted to 0.009 oersted.