Magnetic Peripherals Inc.

Control Data Corporation

Recyclights, Inc.

Impris Technology Incorporated

Douglas J Hennenfent

Allan L Holmstrand

Robert A Johnson

Alan G Kracke

Raymond Eino Jutila

Timothy W Vadnais

Arthur Calderon

Harold James Beecroft

Judy M Ekern

Lloyd M Thorndyke

Thomas Francis Burniece, Iii

Timothy W Vandnais

A crusher adapted to process a feedstock. The crusher includes a pair of crusher rolls for processing a feedstock, the crusher rolls being disposed in a spaced apart relationship with an axis of each crusher roll parallel to one another. Each crusher roll has a plurality of toothed sprockets spaced along the axis of the crusher roll by a spacer disposed between adjacent sprockets. The sprockets of one crusher roll are interleaved with the sprockets of the other crusher roll such that the sprockets of one crusher roll are aligned with the spacers of the other crusher roll. A lateral displacement device is operably coupled to the pair of crusher rolls and is shiftable between a first position wherein the sprockets and spacers of the pair of crusher rolls are interleaved and a second disengaged position wherein the sprockets and spacers of the pair of crusher rolls are disengaged. The lateral displacement device has a biasing member acting to urge the pair of crusher rolls into the interleaved position.

Sprocket crusher

A process for assembling the I core and C core element of a ferrite magnetic transducer core includes the steps of depositing by sputtering a gap material on the gap face of one core element. A magnetic material of the type which can be bonded to ferrite by heat and pressure is then sputter deposited on the gap material. The surface of the magnetic material is then juxtaposed to the gap face of the other element and heat and pressure below a pint which may affect the ferrite's magnetic characteristics is used to diffusion bond the two elements to each other. It is possible to use a layer of Sendust Fe-Si-Al high permeability alloy or other high permeability material as the magnetic material deposited on the gap material if this enhancement of the core is desired. In any case, higher than customary clamping pressure along with lower than customary temperature is used to effect the bond.

Method for manufacturing a magnetic head core with a flux gap having a

Apparatus for compressing against each other for bonding by use of a granule clamp the I and C bars which comprise the O bars from which head cores may be cut, includes a rotating frame so that the angular orientation of the O bars may be changed after embedding them in the granules. This allows bonding glass rods to be placed in the interior openings of the unbonded O bars and then by rotating the frame, cause the glass rods to fall into a position adjacent to the interior edge of the flux gap, and at the same time keep the plane of the flux gaps normal to the axis of the granule clamp's pressure die. When heat is then applied to the unbonded O bars, gravity draws the bonding glass into a fillet adjacent the interior edge of the flux gap.

Granule vise for manufacturing a magnetic head core with a glass fillet

A method of calibrating an analog machining sensor of the varying resistance type which has been deposited on a surface involves depositing adjacent it with great positional accuracy relative to a feature on the surface, discrete machining sensors. As machining takes place, the discrete sensor's continuities are successively broken as the analog sensor's height is reduced and its resistance increased. Measuring the resistance of the analog sensor at the time each discrete sensor breaks yields values from which the position of the analog sensor's machined edge can be very accurately related to the position of the feature on the surface.

Method for calibrating a machining sensor

Apparatus for precisely machining the surface of a workpiece comprises a rotating plate with a flat, horizontal abrasive-laden surface against which the workpiece surface is forced by gravity. The workpiece is carried on the free end of an arm pivotably supported remote from the end of the arm carrying the workpiece. Loading of the workpiece work surface can be varied by shifting weights along the length of the arm or transverse to the length of the arm. The workpiece itself can comprise a bar on which several magnetic transducing heads have been deposited. Machining the workpiece surface to a preferred position accurately defines a dimension of choice, such as the throat height of these transducers.

Precision lapping system

A workpiece carrier includes a flat support surface to which a workpiece is attached by bonding. The carrier includes means for bending the carrier support surface so that it becomes concave. When dealing with a relatively flexible workpiece, one can cause the workpiece's surface to be machined to attain a convex shape by bending the support surface of the carrier concavely, and then bonding the workpiece attachment surface to the carrier while the carrier support surface is concavely bent. Allowing the carrier's support surface to assume a less concave shape then imparts a convex shape to the surface of the workpiece to be machined.

Method for attaching a workpiece to a workpiece carrier

A workpiece carrier has a support bar centrally supported at one end of a stem portion. The stem is carried at its opposite end on a base. Columns are interposed between the ends of the support bar and the base. Heat is applied to the columns, preferably by resistive heating elements, to heat them and cause their thermal expansion, causing the support bar ends to be bent away from the base. A relatively flexible workpiece which has been bonded to the support arms on a surface facing away from the base will undergo the same bend.

Workpiece carrier

Apparatus for mounting a thin flexible grinding wheel to allow accurate cutting of kerfs therewith. A method of precision assembly of the apparatus is also disclosed.

Method of aligning a precision grinding wheel assembly

A magnetic transducing core having a transducing face defined by planes whose surfaces comprise substantially parts of ferrite grains, and a method for producing this core. The method involves proper selection of the grit size and binder of a diamond grinding wheel, machining its sides to precise parallelism with each other, mounting it on a highly accurate air bearing, rotating it at high speed, and feeding a work piece ferrite bar from which the core is cut into the rotating wheel. These techniques prevent axial run-out between the edge of the cutting portion of the wheel and the work piece greater than 2.5 microns. A preferred embodiment includes a high pressure jet of coolant impinging on the wheel just ahead of the cutting interface.

Method of manufacturing narrow track ferrite head cores

Precision grinding wheel mount

A magnetic head is manufactured by depositing a layer of spacer material onto the facing surfaces of the magnetic cores; the thickness of each layer being approximately one-half the length of the intended gap and the thicknesses of both layers together being approximately equal to the thickness (length) of the gap. A layer of bonding glass is deposited onto the surfaces of the spacer layers and the cores are pressed together at an elevated temperature to fuse the glass layers and extrude most of the glass.

Method of forming gaps in magnetic heads

An article and a method for manufacturing the same, for use as a jaw face of a vise and which applies pressure evenly along any approximately flat surface clamped therein. The face comprises a plurality of cantilevered beams integral with the body of the jaw. The beams are spaced apart from each other and in the preferred embodiment have along a corresponding exterior surface of each, a pair of projections the tips of which are tangent to a geometrically flat plane. When the jaw is used, the projections bear against a flat surface of the workpiece to be clamped and the individual beams deflect slightly to correct for deviations from flatness in the flat surface, thereby assuring that the clamping force is distributed relatively evenly along the surface. A preferred method for manufacturing this article comprises the making of a plurality of cuts perpendicular to the jaw face of a block, which carries the projections. A second slot is cut to completely intersect each first slot, cutting the entire breadth of a first side intersecting the jaw face, and extending partially toward a second side opposing the first and also intersecting the jaw face. If more deflection is required, a third slot similar to the second but cutting the entire breadth of the second side and extending toward the first side in spaced relation to the second slot may be cut.

Method of machining vise jaw face

Apparatus for increasing the density of data tracks on the recording surfaces of a disc memory of the type having at least one pre-recorded servo track which is continuously read by a servo head whose output signal changes with its position relative the track and is constantly adjusted to maintain a predetermined servo head output signal condition, without increasing the number of servo tracks in the memory. The improvement comprises a servo head having a plurality of flux paths, each passing through a signal winding, and having adjacent read gaps arranged and spaced such that by successively employing one or another of the read gaps to sense a servo track, the number of data tracks can be increased by an integer multiple. Signal winding selection apparatus is added which receives the track address from the external user, and which, dependent thereon, selects one of the signal windings and supplies its servo signal to the controller which shifts the servo arm and maintains the selected servo gap in the desired position adjacent the desired servo track.

Magnetic read head with offset flux gaps

A method for manufacturing a magnetic core for use in data transducing, characterized by having the depth of the shallower flux gap face precisely equal to a predetermined value. The method involves machining a notch in the flux gap face of one element at a precise distance from a reference surface before bonding of the two elements of the core together. The transducing surface can then be machined after assembly to an exact distance from the reference surface to automatically determine the desired flux gap depth.

Magnetic transducer head core manufacturing method

An article and a method for manufacturing the same, for use as a jaw face of a vise and which applies pressure evenly along any approximately flat surface clamped therein. The face comprises a plurality of cantilevered beams integral with the body of the jaw. The beams are spaced apart from each other and in the preferred embodiment have along a corresponding exterior surface of each, a pair of projections the tips of which are tangent to a geometrically flat plane. When the jaw is used, the projections bear against a flat surface of the workpiece to be clamped and the individual beams deflect slightly to correct for deviations from flatness in the flat surface, thereby assuring that the clamping force is distributed relatively evenly along the surface.

Growing community of inventors

Minneapolis, MN, United States of America

Douglas J Hennenfent