US3864752A

US3864752A - Magnetic head assembly having a slotted body portion of elastic material for clamping a transducer and method of manufacture therefor

Info

Publication number: US3864752A
Application number: US423170A
Authority: US
Inventors: Herbert E Thompson
Original assignee: Shugart Associates Inc
Current assignee: Shugart Associates Inc
Priority date: 1973-12-10
Filing date: 1973-12-10
Publication date: 1975-02-04
Anticipated expiration: 1992-02-04

Abstract

A magnetic head assembly and the method of manufacture therefor is disclosed which includes a housing having long and short body portions and a magnetic transducer comprising first and second core portions that are clamped in the respective body portions. The body portions are made of a nonmagnetic elastic material and include core-gripping surfaces defined by aligned slots cut through respective mating surfaces of the body portions. Prior to assembly, the body portions are permanently deformed by applying forces that exceed the elastic limit of the body material whereby the core-gripping surfaces are spaced apart by a distance less than the thickness of the core portions. Thereafter, the coregripping surfaces are forced apart to receive the respective core portions. When the forces are released, the core-gripping surfaces spring back to tightly clamp the core in the slots.

Description

United States Patent Thompson Feb. 4, 1975 [75] Inventor: Herbert E. Thompson, Los Gatos,

Calif.

[73] Assignee: Shugart Associates, Inc., Sunnyvale,

Calif.

[22] Filed: Dec. 10, I973 [21] Appl. No.: 423,170

[56] References Cited UNITED STATES PATENTS 6/1956 Gumbert 360/128 3/1967 Maryatt et al. 360/129 9/1967 Hanson 360/121 12/1969 Kronfeld 360/129 3,484,565 12/1969 Kronfcld et al 360/129 3,508,229 4/1970 Stencel, Jr. et al 360/129 Primary Examiner-Alfred I-I. Eddleman Attorney, Agent, or Firm-Claude A. S. Hamrick; Thomas E. Schatzel [57] ABSTRACT A magnetic head assembly and the method of manufacture therefor is disclosed which includes a housing having long and short body portions and a magnetic transducer comprising first and second core portions that are clamped in the respective body portions. The body portions are made of a nonmagnetic elastic material and include core-gripping surfaces defined by aligned slots cut through respective mating surfaces of the body portions. Prior to assembly, the body portions are permanently deformed by applying forces that exceed the elastic limit of the body material whereby the core-gripping surfaces are spaced apart by a distance less than the thickness of the core portions. Thereafter, the core-gripping surfaces are forced apart to receive the respective core portions. When the forces are released, the core-gripping surfaces spring back to tightly clamp the core in the slots.

19 Claims, 12 Drawing Figures PATEI-ITEU FEB 975 SHEET 3 II 3 m9 //0 U M H 02%|, [08

mail me man II5VH lll H Ha l IIQH Fig. 11

FORMING METAL POSITIONING INTO TWO CORE WITHIN BODY MEMBERS SPREAD GAP OF BODY MEMBER SLOTT I NG REMOVING EACH OF THE FIXTURE BODY MEMBERS LAPPING MATING LAPPING AND POLISHING SURFACES OF MATING SURFACES OF BODY MEMBERS BODY MEMBER/ CORE ASSEMBLY DEFORMING I BODY MEMBERS SECURING BODY INWARDLY ABOUT MEMBERS INTO THE SLOT INTEGRAL MAGNETIC TO FORM GAP HEAD ASSEMBLY SPREADING THE LAPPING SPHERICAL GAP WITH SURFACE ON MAGNETIC A FIXTURE HEAD ASSEMBLY Fig i2 MAGNETIC HEAD ASSEMBLY HAVING A SLOTTED BODY PORTION OF ELASTIC MATERIAL FOR CLAMPING A TRANSDUCER AND METHOD OF MANUFACTURE THEREFOR BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to magnetic head assemblies and methods of manufacture therefor and, more particularly, to magnetic head assemblies having a slotted body portion made from an elastic material for clamping a magnetic transducer in the slot.

2. Description of the Prior Art Magnetic head assemblies have long been used for recording and reproducing bits of information on relatively moving magnetic mediums, such as magnetic discs, magnetic drums and magnetic tape. Magnetic discs may be either rigid or flexible. The rigid disc including an aluminum disc-shaped substrate which is coated with a magnetizable material and which rotates at high speeds under a magnetic head assembly, thereby forming memory tracks arranged in a series of concentric circles about the center of the disc. In applications which require high data transfer rates noncontact recording schemes have been used so as to avoid the wear problems associated with contact recording. In non-contact recording schemes, the magnetic heads are supported by a self-acting air bearing created between the head and the disc during relative rotation therebetween with the air bearing surface being designed to insure that the spacing is relatively constant. There flying heads are expensive to fabricate since extremely precise machining of the air bearing surface of the slider body is required in order to obtain the exact aerodynamic characteristics. Severe problems have also been encountered in positioning and bonding a magnetic transducer within the slider body.

In flexible disc systems, the magnetic medium comprises a flexible mylar substrate having magnetic material secured thereto to provide the recording surfaces. In recording and reproducing information in these systems, the magnetic transducers contact the recording surface. Compliance between the transducer in the flexible medium is affected by utilizing pressure pads which continuously conform the disc against the contour of the transducing surface of the head assembly.

Heretofore, the magnetic head assemblies used in flexible disc drive systems have incorporated much of the technology developed for flying heads. For exam ple, the transducer has been bonded to the head assembly with epoxy. In epoxying the magnetic transducer into the head assembly many steps are involved. The steps include positioning the transducer in a housing, placing the housing in a fixture, applying epoxy to the selected regions to be bonded, placing the epoxied assembly in an oven, removing the assembly after the bond is established, and removing the housing from the fixture. Because of the labor involved, the epoxy process is very expensive. In addition to the expense involved, another disadvantage is that subsequent lapping operations generate abrasive particles which become embedded in the epoxy surrounding the transducer, tending to cause severe wear of the magnetic medium during contact recording. In addition, because the coefficients of thermal expansion and hygroscopic expansion for the epoxy and the materials making up the magnetic transducer and the housing are unequal,

relative displacements are set up in the bond region as a temperature differential and/or a humidity differential is applied to the three materials. Another disadvantage is that the epoxy is softer than either the transducer or the housing and tends to become depressed upon continuous contact with the recording medium, thus pushing the transducer above the housing surface in a manner that causes the transducer to gouge the recording medium during contact recording.

SUMMARY OF THE PRESENT INVENTION It is therefore a primary object of the present invention to provide a magnetic head assembly which is simple in structure. inexpensive to fabricate, and which provides reduced relative movement between the mag netic transducer core and the housing.

Still another object of the present invention is to provide a process for fabricating magnetic head assemblies which utilizes self-fixturing to reduce labor costs and that costs much less than processes requiring an epoxy bond.

Briefly, the present invention is directed toward a magnetic head assembly including a housing having two mating body portions and a magnetic transducer comprising core portions that are clampingly secured within the body portions. The body portions are made of a non-magnetic elastic material and include coregripping surfaces defined by aligned slots cut through respective mating surfaces of the body portions. The body portions are permanently deformed by stresses that exceed the elastic limit of the body material so that the core-gripping surfaces are spaced apart by a distance less than the thickness of the core portions. The core-gripping surfaces are forced open into a spacedapart condition for receiving the core portions and, upon removal of the force, spring back against the core so as to tightly secure the core therewithin.

In another embodiment of the invention, a method is disclosed for fabricating the magnetic head assembly which comprises the steps of stamping body portions from a stainless steel sheet, punching holes through and slotting the body. portions, counterboring one of the body portions adapted to receive and erase core assembly, lapping the mating surfaces on each of the body portions, deburring and passivating the body portions, permanently deforming the body portions inwardly about an axis through the slot to form a preselected controlled gap, spreading the gap with an appropriate fixture, positioning a completed portion of a magnetic core in the spread gaps in the body portions, removing the fixture so as to enable the core-gripping surfaces defined by the gap to spring against and clampingly secure the magnetic core within the body, applying a terminal strip on the body, lapping transducing surfaces of the body portions to define a preselected throat height in the core assembly, polishing the lapped surface, loosely assembling the body portions to form a housing, aligning the pole tips of the magnetic core, and securing the assembly into an integral unit.

The principal advantage of the present invention is that it provides substantial cost reduction in fabricating magnetic head assemblies.

Another advantage of the present invention is that the magnetic transducer assembly is firmly secured in the magnetic head assembly in a manner that reduces wear on flexible magnetic disc surfaces during recording and reproducing operations.

These and other objects and advantages of the present invention will no doubt become apparent to those of ordinary skill in the art after having read the following detailed description of the preferred embodiments which are illustrated in the several figures of the drawings.

IN THE DRAWINGS FIG. 1 is a perspective view of the magnetic head assembly in accordance with this invention;

FIG. 2 is a side elevational view of the magnetic head assembly formed in accordance with this invention;

FIG. 3 is a front elevational view of one of the body members comprising the magnetic head assembly of this invention;

FIG. 4 is a side elevational view of the read/write magnetic core portion and the erase core assembly that is inserted into the body member illustrated in FIG. 3;

FIG. 5 is a side elevational view of the read/write magnetic core portion and the erase core assembly illustrated in FIG. 4;

FIG. 6. is a rear elevational view of another body member of the magnetic head assembly of this invention;

FIG. 7 is a plan view of the body member of FIG. 3 illustrating the fixturing for producing deformation of the member;

FIG. 8 is a view similar to FIG. 7 illustrating the deformed body member;

Flg. 9 is a view similar to FIGS. 7 and 8 showing the step of spreading the core-gripping surfaces of the deformed body member in accordance with this invention;

FIG. 10 is a second embodiment of the body member in accordance with this invention;

FIG. 11 is a third embodiment of a body member in accordance with this invention for use in a multichannel magnetic head assembly;

FIG. 12 is a schematic diagram in block form illustrating the method of farbicating the magnetic head assembly in accordance with this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings and more particularly to FIGS. 1 and 2 thereof, a magnetic head assembly, generally designated by the number 10, is illustrated in accordance with the present invention. FIG. 12 illustrates in block diagram form the method for fabricating this magnetic head. The assembly 10 comprises a housing 15 that includes a long body member 11 and a short body member 12, and an electromagnetic transducer assembly 13 secured to the body members 11 and 12 in a manner and by means to be described in detail hereinafter.

The long body member as illustrated in FIG. 3 is in the shape of a channel that resembles the letter C in cross section, and is stamped from a nonmagnetic elastic metal that is able to retain a spring force upon deformation beyond its elastic limit. The body member 11 includes a top flange portion 20, a bottom flange portion 21, and an end portion 22 or base that interconnects the two flange portions in an integral structure. The flange portions and 21 terminate in mating surfaces 40 and 41 respectively. The member is normally stamped from a non-magnetic metal sheet so as to form a dimple portion 23 protruding outwardly from the middle of the bottom flange portion 21, which dimple will provide a support for pole tips of the included electromagnetic transducer assembly 13 and a raised recording-media-contacting surface. Apertures 24. 25, 26 and 27 are punched through the end portion 22. The

middle apertures

26 and 27 receive

bolts

28 and 29 for securing the two body members 11 and 12 together, and the

outer apertures

24 and 25 providing mounting holes for securing the magnetic head assembly to a head support. as with bolts (not shown). A portion of the top flange portion 20 is removed. as by sawing. to form an opening 30 having a key slot 31 extending inwardly into the middle of the top flange portion so as to define coregripping surfaces and 36. A slot 32 that is parallel with slot 31 is sawed into the middle of the dimple portion 23 in the bottom flange portion 21 so as to define core-gripping

surfaces

33 and 34. The mating surface is counterbored to provide a relief for receiving the erase element of the magnetic transducer assembly.

The short body member 12, as illustrated in FIG. 6. is similarly formed into a C-shaped channel and includes a top flange portion 50, a bottom flange portion 51 and an end portion 52 that interconnects flange portions and 51 so as to form an integral structure. The

flange portion

50 and 51 respectively terminate in mating surfaces 45 and 46 respectively. The distances between the top and bottom flange portions of the long body member 11 and the short body member 12 are substantially equal so that corresponding bottom mating surfaces 40 and 45, and corresponding mating surfaces 41 and 46 will coincide when secured together during assembly. A dimple portion 53 protruding downwardly from the middle of the bottom flange portion 51 is stamped into the short body member 12 for supporting the pole tops of its associated portion of the magnetic core assembly. Apertures 55 and 56 which are spaced apart the same distance as

apertures

25 and 26 are then punched through the center of the end portion 52 for receiving

bolts

28 and 29. An opening 57 including a slot portion 58 is sawed into the top flange portion 50 and slot 60 is sawed into the bottom flange portion 51 approximately through the center of the dimple 53 and parallel with slot 58, thereby defining core-gripping

surfaces

61 and 62 and 69 and 70, respectively, that are substantially perpendicular to mating surface 45. Mating surfaces 40, 41, 45 and 46 are lapped to provide a relatively smooth surface finish.

In fabricating the magnetic head assembly the body members 11 and 12 are deburred and passivated. In the deburring operation the burrs formed during the slotting and counterboring operations are removed, preferably by brushing the bodies with a wire-bristled brush. In the passivation operation the members are immersed in a chemical bath comprising nitric acid to remove all contaminants thereon.

The material used to form the body members is a non-magnetic, non-ferrous, non-corrosive metal that is close in wear characteristics to the material forming the core. In the preferred embodiment the body members are fabricated from stainless steel stock that is approximately 0.050 inch thick.

The electromagnetic transducer assembly 13 comprises an l-shaped core assembly 70, a C-shaped core assembly 71. An erase core assembly 72 is mounted on I-core assembly 70.

The l-core assembly as shown in FIGS. 4 and 5 comprises a plurality of magnetic Iaminations 74 that are held together by frets 76 and spaced therefrom by nonmagnetic stainless steel spacers 75. Preferably, l2 layers of high-mu 800 magnetic material are laminated together. The outer frets 76 include outwardly protruding

portions

73 and 79 from its respective front and back surfaces respectively. Notches 77 are removed from the lowermost opposed side of the front face of the front protruding portion 73 so as to define a shoulder 78.

The erase core assembly 72 comprises an integral magnetic member 80, preferably of high-mu 800 material that includes a lower U-shaped bight portion 81, angled shoulder portions 82 and upstanding leg portions 83. The erase assembly is mounted on the I-core assembly with the angled shoulder portions 82 abutting the respective shoulder portions 78 within the notched recess 77 of the I-core assembly. Secured against the side surfaces of the legs 83 is a magnetic backbar 84 having an erase coil 85 would therearound and extending rearwardly between and above the back protruding portion 79 of the l-core assembly. The spacer 75 of the I-core forms a non-magnetic gap between the erase pole tips which will subsequently be formed from the bight portion in order to enable an erase flux path to be formed transverse to the direction of the recording path.

The C-bar assembly 71 as illustrated in FIGS. 2 and 6 comprises a plurality of laminated magnetic layers 86, preferably of the same high-mu 800 material that is used to form the erase core and the I-core. A stainless steel fret 87 secures the lamination together. A centraltapped red/write coil 88 is wound around the leg of the C-core assembly between the top and bottom base portions thereof and a shoulder 89 protrudes rearwardly from the lower base of the core. In the preferred embodiment, there are twelve magnetic Iaminations and the width of the C-core assembly is 0.022 inches.

An important feature of this invention is the process step of forming a spring force characteristic in the elastic body members 11 and 12, thus enabling the gripping surfaces of these members to clampingly secure the electromagnetic transducer assembly 13 therein.

Referring now to FIGS. 79, the long body member 11 is shown positioned in a fixture, generally designated by the numeral 64, used in this process step. As illustrated in FIG. 7, the fixture 64 comprises three thin similarly shaped

rectangular force members

65, 66 and 67. The first thin rectangular member 65 includes a distal forcing surface directed downwardly toward the inner surface of the end portion 22 aligned with an axis through the

slots

31 and 32. Disposed upwardly toward spaced apart regions of the outer surface of the end portion are the

members

66 and 67. The

members

65, 66 and 67 each have a width less than the width of the end portion. In operation,

members

65, 66 and 67 are forced inwardly against the respective surfaces of the end portion 22 thereby deforming the body member about an axis through

slots

31 and 32 as illustrated in FIG. 8. The stresses applied by the force members are such as to exceed the elastic limit of the stainless steel material comprising member 11, thereby to permanently deform the coregripping surfaces 33 and 34 and 35 and 36 to a separation that is less than the thickness of the core portions. Preferably, the core-gripping surfaces defined by the slot in the unstressed conditions are separated by about 0.024 inches and in the deformed condition by about 0.0I7 inches. The steps in deforming the short body member 12 are similar to those illustrated in FIGS. 7-9. A feeler gauge is used to measure the distance between the deformed coregripping surfaces.

The next step in fabricating the magnetic head assembly in accordance with this invention is illustrated in FIG. 9. In this operation, the inwardly deformed core-gripping surfaces are forced outwardly to a width sufficient to allow the assembled I-core and erase core 72 to be inserted between surfaces 33. 34, 35 and 36 of the long body member 11, which are illustrated in FIG. 9 as being spread open. It is understood that a similar operation is performed on the short body member 12 so as to enable the C-core 71 to be inserted therein. More specifically, in this step the deformed long body member 11 is repositioned in fixture 64 with an orientation opposite to that used to produce the deformation. Thus, the fixture member 65 is directed towards the outer surface of the end portion 22 and the

fixture members

66 and 67 are disposed within the channel directed toward the inner surface of the end portion 22. Movement ofthe

force members

65, 66 and 67 against the end portion causes the core-gripping surfaces to be spread apart and the

slots

31 and 32 opened to a separation greater than the thickness of the I-core assembly 70. Thereafter, the I-core assembly 70 is inserted into the

slots

31 and 32 of the long body member 11 with its rearwardly protruding portion 79 butting against the inner surface of the end portion 22. In accordance with this invention, as the

fixture members

65, 66 and 67 are released, the core-gripping

surfaces

33 and 34 and 35 and 36 spring back against the side surfaces of the I-core assembly in frictional contact therewith so as to clamp the core firmly in position. In a similar operation, the C-core assembly 71 is inserted into slots 58 and 60 in the short body 12, the coregripping surfaces 61 and 62 clampingly secured to adjacent portions of the stainless steel fret 87. In spreading the gap, it should be recognized that the elastic limit of the stainless steel body should not be exceeded.

The next step is to remove the body members 11 and 12 from the fixture 64 and to secure terminals and 91 to the outer top surfaces of the long body member 11 and the short body member 12, respectively, over the top portions of the core assemblies as by cementing. The leads from the center tapped read/write coil 88 and the erase coil 84 are threaded through the

respective openings

57 and 30 and bonded to the

terminals

90 and 91.

Each of the mating surfaces 40, 41 45 and 46 is thereafter lapped so as to remove protruding portions of the core assemblies 70 and 71, and then fine lapped in order to minimize the air gap between mating portions of the core assemblies. I

In the next fabrication operation, the body members 11 and 12 are mated against one another and a nonmagnetic shim 95 is inserted to precisely define the transducing gap between the magnetic core members. After the shim has been inserted the

bolts

28 and 29 are snugged so as to hold mating surfaces of the body surfaces lightly against one another and the pole tips of the core members are aligned. Then the bolts are torqued firm to secure the body members into the integral magnetic head assembly 10.

The head assembly is rough-turned by machining to radius the pole face and to remove protruding portions of the read/write core and the erase core. ln this operation, a portion of the erase core is removed. The bottom base portion of the read/write core that remains after the radiusing defines a throat height distance.

The next step in the process is to lap a spherical shape on the transducing surfaces of the body members and the pole faces of the magnetic cores with the apex of the sphere at the center of the transducing gap. Thereafter, a pigtail is attached to the leads on

terminals

90 and 91 so as to provide the magnetic head assembly of this invention.

In an alternative embodiment, as illustrated in FIG. 10, a relief hole 97 is drilled through the body member 11 at the innermost extension of the

slots

98 and 99. The relief hole 97 has curved surface formed with a diameter greater than the distance between the coregripping surfaces 100, 101, l02-and 103 of the

slots

98 and 99. The relief hole defines a hingelike structure and functionally acts to distribute stresses that tend to form during deformation and increases the spring force exerted by the core-gripping surfaces against a core assembly (not shown) when inserted therein.

Still another embodiment is illustrated in FIG. 11 wherein a plurality of

parallel slots

105, 106 and 107 are sawed into a body member 108 which is positioned in fixture 109. The fixture 109 comprises force members 110, 111 and 112 directed against the inner surface of the end portion of the body member. As the force members are moved against the end portion, each of the slots is deformed as illustrated in FIG. 7, creating spring forces directed toward the core-gripping surfaces defined by each of the slots. After subsequent slot spreading operations similar to those previously described, cores are inserted in each of the slots. Mating together of two assemblies of this type provides a multichannel magnetic head assembly, each channel being defined by each pair of mating magnetic cores received in respective aligned slots in the two assemblies.

In operation, as the magnetic media is moved over the transducing gap of the magnetic head assembly of this invention, information is either read by the head or written by the head in a manner well-known to the art. The erase core assembly is energized during all write operations to trim the sides of the written path by providing an erase flux in a direction substantially perpendicular to the direction of the written path between the outer erase core and the outermost magnetic laminations in the read/write core. Thus, old information in this region is erased.

The terms up and down and words of similar import as used herein are intended to apply only to the position of the parts as illustrated in the drawings, since it is well known that magnetic heads of the general type illustrated may be mounted or oriented in many different positions during fabrication.

From the above, it can be seen that' a magnetic head assembly and the method of manufacture thereof has been described which fulfills all of the objects and advantages set forth above.

While there has been described what are at present considered to be the preferred embodiments of the invention, it will be understood that various modifications may be made therein and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

l. A magnetic haead assembly comprising:

a magnetic transducer assembly including a first magnetic core and a second magnetic core, each core having a certain width;

a first body member comprised of an elastic material including a first mating surface having a first slot therein, opposed surfaces of said first slot defining first core-gripping surfaces that are normally spaced-apart less than said certain width, said first core being disposed within said first slot when external forces are applied to said first body member to elastically open said first slot to a width more than said certain width, said first slot thereafter being permitted to elastically close so that said first core-gripping surfaces clampingly engage said first core;

a second body member comprised of an elastic material including a second mating surface having a second slot therein, opposed surfaces of said second slot defining second core-gripping surfaces that are normally spaced-apart less than said certain width. said second core being disposed within said second slot when external forces are applied to said second body member to elastically open said second slot to a width more than said certain width, said second slot thereafter being permitted to elastically close so that said second core-gripping surfaces clampingly engage said second core; and

means for securing said first and said second body members together with said first and second mating surfaces in abutting relationship and with said first and second cores aligned to define a magnetic transducing gap.

2. A magnetic head assembly as recited in claim 1 and further comprising an erase core assembly mounted on said first magnetic core to define erase gaps on each side of said first core and substantially normal to said transducing gap for developing erase tracks on each side of the recording track developed by said transducing gap.

3. A magnetic head assembly as recited in claim 1 wherein the surface portions of said first and second body members proximate said transducing gap protrude outwardly to define a raised recording-mediacontacting surface.

4. A magnetic head assembly as recited in claim 3 wherein said raised surface is spherically shaped and said transducing gap is located at its apex.

5. A magnetic head assembly as recited in claim 1 wherein each of said first and said second body members is elongated and generally C'shaped in cross section, said first body member having a first flange portion and a second flange portion interconnected by a first base portion, the region in the middle of said first flange portion having said first slot therein and the region in the middle of said second flange portion having a third slot therein,

said second body member having a third flange portion and a fourth flange portion interconnected by a second base portion, the region in the middle of said third flange portion having said second slot therein, and the region in the middle of said fourth flange portion having said fourth slot therein, said third and fourth slots being aligned with each other.

6. A magnetic head assembly as recited in claim 2 wherein said magnetic transducer assembly includes a read/write coil having conductive leads, and said erase core assembly includes an erase coil having conductive leads, and further including terminal strips secured to a portion of the outer surface of said first and said second body members for receiving said conductive leads of said read/write and erase coils.

7. A magnetic head assembly as recited in claim 1 wherein said first core-gripping surfaces are interconnected by a curved surface defining'the perimeter of a stress reducing relief hole,

8. A magnetic head assembly as recited in claim 1 wherein each said body member comprises a plurality of spaced-apart slots in said mating surface, and further comprising a plurality of magnetic transducer assemblies respectively clampingly secured within each said slot, to provide a multi-channel magnetic head assembly.

9. A method for fabricating a magnetic head assembly comprising the steps of:

permanently deforming a first deformable body member that is comprised of an elastic material and that has a slot defined by spaced-apart facing core-gripping surfaces so as to move said coregripping surfaces toward one another;

applying spreading forces within the elastic limits of said elastic material to said body member to spread said core-gripping surfaces apart a distance sufficient for said slot to receive a first magnetic core portion;

inserting said first core portion into said slot between said core-gripping surfaces; and

releasing said spreading forces, whereby said coregripping surfaces spring against said core portion to clamp said core portion to said body member.

10. A method for fabricating a magnetic head assembly as recited in claim 9 wherein said body member comprises an elongated member that is C-shaped in cross section and wherein the step of permanently de forming said deformable body member is preceded by the step of positioning said body member in a fixture that has three spaced-apart force members such that the middle force member is directed toward the inner surface of the base of said body member between and in a direction substantially parallel to said coregripping surfaces.

11. A method for fabricating a magnetic head assembly as recited in claim 10 wherein the step of applying spreading forces to said body member is preceded by the step of repositioning said deformed body member in said fixture with said middle force member directed toward the outer surface ofthe base of said body member in a direction substantially parallel to said coregripping surfaces.

12. A method for fabricating a magnetic head assembly as recited in claim 9 and repeating the same sequence of steps with a second deformable body member and a second core portion, followed by the step of mating said second core portion with said first core portion to provide a magnetic transducer and then securing said first and said second body members together to form the magnetic head assembly.

13. A method for fabricating a magnetic head assembly as recited in claim 9 wherein said deformable body member includes at least two sets of spaced-apart coregripping surfaces and wherein a magnetic core is inserted between each set of said core-gripping surfaces so as to provide a multi-channel magnetic head assembly.

14. A method for fabricating a magnetic head assembly as recited in claim 10 including prior to the step of positioning said body member in a fixture, the step of cutting a transverse slot into one side of said body member, the opposed surfaces of said slot defining said core-gripping surfaces.

15. A method for fabricating a magnetic head assembly comprising the steps of:

forming a first elongated body member, that is comprised of an elastic material, into an elongated channel that includes a base and a pair of outwardly extending flanges, the distal ends of said flanges defining first mating surfaces;

slotting the mating surface of one of said flanges of said first body member so as to define first opposed core-gripping surfaces;

permanently deforming said first body member so as to move said first core-gripping surfaces toward one an other to define a first controlled gap;

spreading said first core-gripping surfaces with force members to open said first gap sufficient to receive a first magnetic core portion;

inserting said first magnetic core portion in said first removing said force members whereby said first coregripping surfaces spring against and clampingly secure said first core portion within said first body member so as to provide a first unit;

forming a second elongated body member, that is comprised of an elastic material, into an elongaged channel that includes a base and a pair of outwardly extending flanges, the distal ends of said flanges defining second mating surfaces;

slotting the mating surface of one of said flanges of said second body member so as to define second opposed core-gripping surfaces;

permanently deforming said second body member so as to move said second core-gripping surfaces toward one another to define a second controlled p spreading said second core-gripping surfaces with force members to open said second gap sufficient to receive a second magnetic core portion;

inserting said second magnetic core portion in said second gap;

removing said force members whereby said second core-gripping surfaces spring against and clampingly secure said second core portion within said second body member so as to provide a second unit; and

fastening said first and second units into a magentic head assembly.

16. A method for fabricating a magnetic head assembly as recited in claim 15 wherein the step of fastening said first and second units includes the step of loosely securing said first and second mating surfaces together with said first and second core portions aligned so as to provide a magnetic transducer, and then followed by the step of tightly securing said units together.

17. A method for fabricating a magnetic head assembly as recited in claim 15 including, prior to the step fastening said first and second units into a magnetic head assembly, the step of lapping tranducing surfaces on said flanges of said first and second body members proximate said first and second cores to define a preselected throat height in said first and said second cores.

18. A method for fabricating a magnetic head assembly as recited in claim 15 wherein said core-gripping surfaces of said first and said second body members are 5 for receiving said erase comprised of nonmagnetic stainless steel.

19. A method for fabricating a magnetic head assembly as recited in claim 15 including the step of positioning as erase core assembly on said first core portion and the step of forming a recess in said first body member core assembly. 1k k Herbert-(E. Thompson ied that error appears in the above-identified patent tars Patent are hereby corrected as shown below:

Column 3, line 30, "FIg." should read --FIG.--;

Column 3, line 40, "farbicating" should read --fabricating-;

Column 4, line 14, "coregripping" should read --coregripp. ng-;

Column 5, line 34, "red/write" should read -read/write-- Column 8, line 2, "haead" should read --head--.

Signed and sealed this 22nd day of-April- 1975.

(SEAL) Attest C. MARSHALL DANN RUTH C. MASON Commissioner of Patents- Attesting Officer and Trademarks

Claims

1. A magnetic haead assembly comprising: a magnetic transducer assembly including a first magnetic core and a second magnetic core, each core having a certain width; a first body member comprised of an elastic material including a first mating surface having a first slot therein, opposed surfaces of said first slot defining first core-gripping surfaces that are normally spaced-apart less than said certain width, said first core being disposed within said first slot when external forces are applied to said first body member to elastically open said first slot to a width more than said certain width, said first slot thereafter being permitted to elastically close so that said first core-gripping surfaces clampingly engage said first core; a second body member comprised of an elastic material including a second mating surface having a second slot therein, opposed surfaces of said second slot defining second core-gripping surfaces that are normally spaced-apart less than said certain width, said second core being disposed within said second slot when external forces are applied to said second body member to elastically open said second slot to a width more than said certain width, said second slot thereafter being permitted to elastically close so that said second core-gripping surfaces clampingly engage said second core; and means for securing said first and said second body members together with said first and second mating surfaces in abutting relationship and with said first and second cores aligned to define a magnetic transducing gap.

3. A magnetic head assembly as recited in claim 1 wherein the surface portions of said first and second body members proximate said transducing gap protrude outwardly to define a raised recording-media-contacting surface.

5. A magnetic head assembly as recited in claim 1 wherein each of said first and said second body members is elongated and generally C-shaped in cross section, said first body member having a first flange portion and a second flange portion interconnected by a first base portion, the region in the middle of said first flange portion having said first slot therein and the region in the middle of said second flange portion having a third slot therein, said Second body member having a third flange portion and a fourth flange portion interconnected by a second base portion, the region in the middle of said third flange portion having said second slot therein, and the region in the middle of said fourth flange portion having said fourth slot therein, said third and fourth slots being aligned with each other.

7. A magnetic head assembly as recited in claim 1 wherein said first core-gripping surfaces are interconnected by a curved surface defining the perimeter of a stress reducing relief hole.

9. A method for fabricating a magnetic head assembly comprising the steps of: permanently deforming a first deformable body member that is comprised of an elastic material and that has a slot defined by spaced-apart facing core-gripping surfaces so as to move said core-gripping surfaces toward one another; applying spreading forces within the elastic limits of said elastic material to said body member to spread said core-gripping surfaces apart a distance sufficient for said slot to receive a first magnetic core portion; inserting said first core portion into said slot between said core-gripping surfaces; and releasing said spreading forces, whereby said core-gripping surfaces spring against said core portion to clamp said core portion to said body member.

10. A method for fabricating a magnetic head assembly as recited in claim 9 wherein said body member comprises an elongated member that is C-shaped in cross section and wherein the step of permanently deforming said deformable body member is preceded by the step of positioning said body member in a fixture that has three spaced-apart force members such that the middle force member is directed toward the inner surface of the base of said body member between and in a direction substantially parallel to said core-gripping surfaces.

11. A method for fabricating a magnetic head assembly as recited in claim 10 wherein the step of applying spreading forces to said body member is preceded by the step of repositioning said deformed body member in said fixture with said middle force member directed toward the outer surface of the base of said body member in a direction substantially parallel to said core-gripping surfaces.

13. A method for fabricating a magnetic head assembly as recited in claim 9 wherein said deformable body member includes at least two sets of spaced-apart core-gripping surfaces and wherein a magnetic core is inserted between each set of said core-gripping surfaces so as to provide a multi-channel magnetic head assembly.

15. A method for fabricating a magnetic head assembly comprising the steps of: forming a first elongated body member, that is comprised of an elastic material, into an elongated channel that includes a base and a pair of outwardly extending flanges, the distal ends of said flanges defining first mating surfaces; slotting the mating surface of one of said flanges of said first body member so as to define first opposed core-gripping surfaces; permanently deforming said first body member so as to move said first core-gripping surfaces toward one another to define a first controlled gap; spreading said first core-gripping surfaces with force members to open said first gap sufficient to receive a first magnetic core portion; inserting said first magnetic core portion in said first gap; removing said force members whereby said first core-gripping surfaces spring against and clampingly secure said first core portion within said first body member so as to provide a first unit; forming a second elongated body member, that is comprised of an elastic material, into an elongaged channel that includes a base and a pair of outwardly extending flanges, the distal ends of said flanges defining second mating surfaces; slotting the mating surface of one of said flanges of said second body member so as to define second opposed core-gripping surfaces; permanently deforming said second body member so as to move said second core-gripping surfaces toward one another to define a second controlled gap; spreading said second core-gripping surfaces with force members to open said second gap sufficient to receive a second magnetic core portion; inserting said second magnetic core portion in said second gap; removing said force members whereby said second core-gripping surfaces spring against and clampingly secure said second core portion within said second body member so as to provide a second unit; and fastening said first and second units into a magentic head assembly.

18. A method for fabricating a magnetic head assembly as recited in claim 15 wherein said core-gripping surfaces of said first and said second body members are comprised of nonmagnetic stainless steel.

19. A method for fabricating a magnetic head assembly as recited in claim 15 including the step of positioning as erase core assembly on said first core portion and the step of forming a recess in said first body member for receiving said erase core assembly.