Video tape recorder

Claim 2

In a magnetic tape wide-band recording apparatus comprising: a frame, a head disc mounted for rotation about an axis, the disc comprising a number of magnetic heads spaced at equal radial distances from the axis of rotation and uniformly spaced around the circumference of the disc, means for supporting the rotatable head disc, means for rotating the disc, a tape guide device comprising concavely curved guide members for guiding the tape in a locally transversely curved condition past a part of the circular path of said electromagnetic heads in a direction transverse to the plane of rotation of the head disc, said members having tape guiding surfaces having a radius of curvature, means for guiding and moving the tape from a supply means to a take-up means, and actuating means for moving the head disc and the concave guide members relative to each other in a direction transverse to the axis of rotation of the head disc between a disengaged position, in which the concave guide members are disposed at a distance from the head disc sufficient to allow the magnetic tape to assume a substantially flat shape, and an operating position, in which the magnetic tape is guided past the circular path of the heads in said locally curved condition, the improvement wherein: the tape guide device further comprises convexly curved guide members disposed on opposite axial sides of the head disc and having tape guiding surfaces having a radius of curvature substantially equal to that of the concave guide members, an axial distance between the convex guide members being greater than the axial distance between the concave guide members, and the concave guide members and convex guide members being movable relative to each other in a direction transverse to the axis of rotation of the head disc, and the concave guide members each form a part of a pressure piece which, in the operating position, presses the locally transversely curved part of the magnetic tape against the convex guide members.

Claim 3

An apparatus as claimed in claim 1, wherein the concave guide members are portions of a single pressure piece only, and the guide members are arranged relative to each other such that in the operating position of the actuating means each convex guide member is separated from the nearest one of the concave guide members by a gap in the axial direction, at which gap the magnetic tape is not in contact with any part of the apparatus.

Claim 4

An apparatus as claimed in claim 2 comprising means, operative while the concave guide members are in an operating position, for aligning the concave guide members directly with respect to the tape guiding surfaces of the convex guide members.

Claim 5

An apparatus as claimed in claim 3, wherein the pressure piece comprises concave supporting members having a radius of curvature which are extensions at ends of the concave guide members, and the apparatus further comprises convex supporting members corresponding to and having a same radius of curvature as the concave supporting members, arranged so that in the operating position of the actuating means said concave supporting members bear against the convex supporting members, and said aligning means comprises resilient means for biasing the concave supporting members against the convex supporting members when in said operating position.

Claim 6

An apparatus as claimed in claim 4, wherein the pressure piece, the convex guide members and the convex supporting members are made of the same non-magnetic material.

Claim 7

An apparatus as claimed in claim 4, wherein the convex supporting members are extensions of and integral with the convex guide members.

Claim 8

An apparatus as claimed in claim 6, wherein the convex guide members and associated supporting members are portions of two drums arranged coaxially one on each side of the head disc, each convex tape guiding surface of a guide member and the associated supporting members consists of a portion of an accurately machined circular cylindrical outer surface of a respective one of said drums, a second portion of said circular cylindrical surface opposite a respective tape guiding surface of the concave guide member being removed to provide clearance for the tape.

Claim 9

An apparatus as claimed in claim 7, wherein each of said drums has an outer surface, a first portion of said outer surface being said circular cylindrical surface, and a second portion being a surface of diameter less than said first portion.

Claim 10

An apparatus as claimed in claim 7, wherein at least one of the drums comprises a bearing coaxial with said circular cylindrical surface, and said support means for the head disc comprises a rotatable shaft carrying the head disc and journalled in said bearing.

Claim 11

An apparatus as claimed in claim 9, wherein said drums accommodate a synchronizing head for synchronizing translational speed of the magnetic tape, and means for transferring signals from stationary parts of the apparatus to and from magnetic heads mounted on the head disc.

Claim 12

An apparatus as claimed in claim 8, wherein said support means for the head disc further comprises an integral mounting block having a plurality of accurately machined faces, two of said faces constituting walls of a V-shaped groove, and means for holding the accurate circular cylindrical surfaces of the drums against said walls of the groove.

Claim 13

An apparatus as claimed in claim 11, wherein said means for rotating the disc comprises a motor having an outer accurate circular cylindrical surface of diameter equal to the diameter of the corresponding surfaces of the drums, said apparatus additionally comprising means for fixing the cylindrical surface of the motor against the walls of the groove.

Claim 14

An apparatus as claimed in claim 12, wherein said means for rotating the disc further comprises a flexible coupling connecting said shaft to an output shaft of the motor.

Claim 15

An apparatus as claimed in claim 11, comprising an electromagnetic audio recording/playback head and an audio erase head mounted on said mounting block.

Claim 16

An apparatus as claimed in claim 1, wherein the concave guide members are portions of a single pressure piece only, and the apparatus comprises a pressure piece support pin, means for positioning the pin on the apparatus, and means for mounting the pressure piece on the support pin for limited omnidirectional movement with respect to the pin.

Claim 17

An apparatus as claimed in claim 15, wherein said means for mounting the pressure piece comprises a bore in the pressure piece, said supporting pin passing through said bore with radial clearance, resilient means for biasing the pressure piece in a radial direction with respect to the supporting pin, and stop means for limiting axial movement of the pressure piece relative to the supporting pin.

Claim 18

An apparatus as claimed in claim 16, wherein said resilient means comprises a plurality of coil springs located in blind bores in the pressure piece extending transversely of the bore for accepting the supporting pin, an end of each spring bearing against the pin.

Claim 19

An apparatus as claimed in claim 1, wherein the actuating means comprises means for moving the concave guide members and the convex guide members relative to the frame simultaneously and in opposite directions.

Claim 20

An apparatus as claimed in claim 18, wherein the concave guide members are portions of a single pressure piece only, and the apparatus comprises a pressure piece support pin, and means for mounting the pressure piece on the support pin for limited omnidirectional movement with respect to the pin; said support means for the head disc further comprises an integral mounting block having a plurality of accurately machined faces, means for holding the convexly curved guide members against said faces, and a first carriage on which the mounting block is mounted; and said actuating means comprises a second carriage on which the pressure piece support pin is mounted, means for slidably driving one of said carriages transversely with respect to the tape, and means coupling the carriages to each other for slidably moving the other carriage transversely with respect to the tape in response to movement of the one carriage transversely with respect to the tape.

Claim 21

An apparatus as claimed in claim 19, wherein said means for guiding and moving the tape comprises two cylindrical guides having axes transverse to the tape, one of said guides being the last transverse axis guide passed by the tape before it reaches the head disc, the other being the first transverse axis guide passed by the tape after it passes the head disc, and means for supporting said two guides for limited axial and radial movement, said actuating means comprises aligning menbers mounted on said mounting block and extending toward the pressure piece for accurately positioning said cylindrical tape guides transversely of the tape guide axes when said actuating means is in the operating position.

Claim 22

An apparatus as claimed in claim 20, wherein said aligning members comprise two pairs of strip-shaped elongated parts, the two parts of each pair extending parallel to one another and transverse to the rotational axis of the head disc, the two parts of each pair being spaced from each other a distance approximately equal to the width of the magnetic tape.

Claim 23

An apparatus as claimed in claim 21, wherein said strip-shaped parts are identical and at distal ends are shaped as two-pronged forks.

Claim 24

A magnetic tape-cassette recording apparatus comprising; a frame; a head disc mounted for rotation about an axis, the disc comprising a number of electromagnetic heads spaced at equal radial distance from the axis of rotation and uniformly spaced around the circumference of the disc; means for supporting the rotatable head disc on the frame; means for rotating the disc; a tape drive capstan mounted in the frame for rotation about an axis transverse to the head disc axis; a pressure roller movably mounted to the frame for rotation about an axis parallel to the drive capstan; a pressure piece comprising concavely curved guide members for guiding magnetic tape in a locally transversely curved condition past a part of the circular path of said electromagnetic heads in a direction transverse to the plane of rotation of the head disc, said members having tape guiding surfaces having a radius of curvature; a tape guide device comprising convexly curved guide members disposed on opposite axial sides of the head disc, and having tape guiding surfaces having a radius of curvature substantially equal to that of the concave guide members, an axial distance between the convex guide members being greater than the axial distance between the concave guide members, the concave guide members and convex guide members being movable relative to each other in a direction transverse to the axis of rotation of the head disc; actuating means for moving the head disc and convex guide members, and the concave guide members, relative to each other in a direction transverse to the axis of rotation of the head disc between a disengaged position, in which the concave guide members are disposed at a distance from the head disc sufficient to allow the magnetic tape to assume a substantially flat shape, and an operating position, in which the magnetic tape is guided past the circular path of the heads in said locally curved condition; a cassette containing magnetic tape and comprising parallel upper and lower walls, long front and rear walls and two side walls shorter than said front and rear walls; two winding spools having parallel axes perpendicular to the upper and lower walls and being arranged in side by side relationship, each spool having a flange for supporting tape wound thereon, the spools being mounted in the cassette for limited radial and axial play; first resilient means for biasing said spools toward the lower wall of the cassette such that upon removal of the cassette from the apparatus the spools will be pressed against the lower wall in order to inhibit rotation of the spools and consequent unwinding of the tape; two cylindrical tape guides mounted near the front wall of the cassette for limited radial and axial play, axes of said tape guides being parallel to the spool axes; and second resilient means for urging the tape guides toward the front of the cassette; and wherein the lower wall of the casette has an opening for passage of the tape drive capstan, and an opening for the passage of the pressure piece; and the front wall of the cassette has openings for the passage of said convex guide members, said electromagnetic heads, and the pressure roller; locating pins connected to the frame for positioning the cassette; winding spindles having axes spaced from each other, parallel to the capstan axis, and having turntables thereon, said turntables arranged to support the cassette spools against pressure of the first resilient means at a height at which the spools are clear of the upper and lower walls of the cassette; said tape guide device also comprising tape guide aligning members extending transverse to said head disc and drive capstan axes, said members being movable with said convex guide members by said actuating means, said members having distal ends arranged to engage said tape guides when said curved guide members are in said operating position; said cassette front wall also having an opening for passage of said aligning members; and wherein, said apparatus being in the disengaged position, said tape is free to extend in a straight line along the front wall of the cassette between said cylindrical tape guides, said tape passing between said concave and convex guide members.

Claim 25

A magnetic tape-cassette recording apparatus comprising; a frame; a head disc mounted for rotation about an axis, the disc comprising a number of electromagnetic heads spaced at equal radial distance from the axis of rotation and uniformly spaced around the circumference of the disc; means for supporting the rotatable head disc on the frame; means for rotating the disc; a tape drive capstan mounted in the frame for rotation about an axis transverse to the head disc axis; a pressure roller movably mounted to the frame for rotation about an axis parallel to the drive capstan; a pressure piece comprising concavely curved guide members for guiding magnetic tape in a locally transversely curved condition past a part of the circular path of said electromagnetic heads in a direction transverse to the plane of rotation of the head disc, said members having tape guiding surfaces having a radius of curvature; a tape guide device comprising convexly curved guide members disposed on opposite axial sides of the head disc, and having tape guiding surfaces having a radius of curvature substantially equal to that of the concave guide members, an axial distance between the convex guide members being greater than the axial distance between the concave guide members, the concave guide members and convex guide members being movable relative to each other in a direction transverse to the axis of rotation of the head disc; actuating means for moving the head disc and convex guide members, and the concave guide members, relative to each other in a direction transverse to the axis of rotation of the head disc between a disengaged position, in which the concave guide members are disposed at a distance from the head disc sufficient to allow the magnetic tape to assume a substantially flat shape, and an operating position, in which the magnetic tape is guided past the circular path of the heads in said locally curved condition; a cassette containing magnetic tape and comprising parallel upper and lower walls, long front and rear walls and two side walls shorter than said front and rear walls; two winding spools having parallel axes perpendicular to the upper and lower walls and being arranged in side by side relationship, each spool having a flange for supporting tape wound thereon, the spools being mounted in the cassette for limited radial and axial play; first resilient means for biasing said spools toward the lower wall of the cassette such that upon removal of the cassette from the apparatus the spools will be pressed against the lower wall in order to inhibit rotation of the spools and consequent unwinding of the tape; two cylindrical tape guides mounted near the front wall of the cassette for limited radial and axial play, axes of said tape guides being parallel to the spool axes; and second resilient means for urging the tape guides toward the front of the cassette; and wherein the lower wall of the casette has an opening for passage of the tape drive capstan, and an opening for the passage of the pressure piece; and the front wall of the cassette has openings for the passage of said convex guide members, said electromagnetic heads, and the pressure roller; locating pins connected to the frame for positioning the cassette; winding spindles having axes spaced from each other, parallel to the capstan axis, and having turntables thereon, said turntables arranged to support the cassette spools against pressure of the first resilient means at a height at which the spools are clear of the upper and lower walls of the cassette; said tape guide device also comprising tape guide aligning members extending transverse to said head disc and drive capstan axes, said members being movable with said convex guide members by said actuating means, said members having distal ends arranged to engage said tape guides when said curved guide members are in said operating position; said cassette front wall also having an opening for passage of said aligning members; and wherein, said apparatus being in the disengaged position, said tape is free to extend in a straight line along the front wall of the cassette between said cylindrical tape guides, said tape passing between said concave and convex guide members.

Claim 26

An apparatus as claimed in claim 23, wherein said cassette locating pins are each a portion of a locating member rigidly mounted on the frame, the pin comprising a portion of the member remote from the frame, a portion between the pin and the frame being a locating stop; and said actuating means comprises a carriage mounted to the frame for movement transverse to the head axis and parallel to the lower wall of the cassette, in said operating position the carriage engaging said stops for accurate positioning.

Claim 27

An apparatus as claimed in claim 24, comprising in addition a guide pin mounted to the frame, and wherein: the carriage comprises a sliding plate having guide edges and a given thickness; said locating members comprise guide grooves for guiding the first carriage in its sliding movement, and having a width slightly greater than the thickness of the sliding plate, said edges engaging said grooves; the sliding plate has a slot extending in the direction of carriage movement, through which the guide pin extends, the slot being locally enlarged at a region surrounding the guide pin when said carriage is in the operating position so that the guide pin is clear of the sliding plate at all sides; and the sliding plate comprises a first, straight locating stop edge and a second, V-shaped locating stop edge for engaging said stops when in said operating position.