U.S. Philips Corporation

Bts Broadcast Television Systems Gmbh

Robert Boschgmbh

Hartmut Willmann

Richard Heinz

Gerhard Falk

Jorn Lutzeler

Werner Maack

Wolfgang Fell

Peter Gunschmann

Peter Lameli

Ludwig Dittmann

Manfred Willomitzer

Josef Walter

Willi Hartmann

Ralf Matwin

A magnet-head device for a magnetic-tape apparatus having a rotatably supported head disc carrying magnetic heads (10) at its periphery. A magnetic head has lateral additional limbs (12) which extend into the path of the magnetic tape (14), so that their end faces (12a) form a common contact face with the end face (11a) of the magnetic head (10).

Magnetic head with lateral shielding limbs and a common contact face

A rotary scanning device having a stationary upper and lower drum (1,2) is proposed, in which a cylindrical insert (15) with a servo head (16) is arranged in a radial bore (14) in the lower drum (2). The cylindrical insert (15) is secured to the circumference of a ring (18) which is concentrically supported in the lower drum (2) and which has an axial groove (19) in its circumferential surface for the adjustment of the angular position of the ring (18).

Rotary scanning device

A rotary scanning device is proposed with a rotary body carrying at its periphery a plurality of magnetic recording heads which can be driven by associated recording amplifiers. The individual recording amplifiers are accommodated on circuit boards which are mounted in a paddle-wheel configuration between two annular conductor boards by means of holders. The two annular conductor boards are rotationally locked to the rotary body. The circuit boards have a forward inclination in the direction of rotation of the rotary body.

A scanning device for a magnetic-tape apparatus is proposed, which device comprises a stationary upper drum section (1) and lower drum section (2) and a head disc (10) which rotates in a gap (5) between the drum sections. In its upper radial surface and its lower radial surface the head disc (10) has segmental recesses (26, 27) for accommodating magnetic heads (11) secured to head mounts (12). At one side of the head disc (10) the recesses (26, 27) accommodate magnetic recording heads and at the other side said recesses accommodate the magnetic reproducing heads.

Rotary head disc for a magnetic-tape apparatus having reproducing heads

For oblique track scanning of magnetic tape which is looped around a two-part drum (1, 2) separated by a gap (5) in which magnetic heads (11) affixed to a headwheel revolve, the rotary transformers connecting the magnetic heads on the headwheel to fixed parts of the scanning device are provided by inner and outer magnetic core rings in which windings are embedded for a number of transformers. One group of these rotary transformers (18, 19) is located above the headwheel disk structure (10, 25) in such a way that outer magnetic core rings are fixed in a bore of the fixed upper drum (1) and inner magnetic core rings (19) are affixed to a seating shell (25) that connects the headwheel disk (10) to its driving shaft. Another group of rotary transformers (10, 21) is located beneath the rotary headwheel disk structure (10, 25) and in this case the outer magnetic core rings (20) are affixed to the inner wall of the rotary headwheel disk structure (10, 25) and the inner magnetic core rings are affixed to the outer wall of the bearing (15) of the shaft (14) that drives the rotary headwheel disk.

Scanning device for magnetic tape with special disposition of rotary

A scanning device for a magnetic tape recording and playback equipment of the oblique track type has a drive shaft (9) for a rotary head wheel (4) mounted in a duplex ball bearing (10) centered on the orbit plane of the magnetic heads which revolve on the circumference of the head wheel between the two halves of a tape-guiding drum. A support bearing (19) is affixed in the bottom of a housing (17) which houses the drive motor and is held in a downward extending socket at the bottom of the lower half of the drum. The housing can be tilt-shifted slightly for shifting the support bearing and then held, by three screws accessible from below, in the correct position for aligning the orbit of the magnetic heads in the gap between the two halves of the drum.

Scanning device for magnetic tape with special bearing arrangement for

A magnetic head affixed to the underside of a carrier body mounted at the periphery of a head-wheel for scanning oblique tracks on a magnetic tape is provided with shielding of ferrite, mu-metal or amorphous iron, to reduce magnetic crosstalk. The shielding surrounds the part of the magnetic head that projects beyond the head carrier body except for a small portion near the polished surface that needs to be left uncovered to avoid interfering aerodynamically with the contact of the magnetic head with a magnetic tape. One piece of the shielding is of rectilinear shallow U-shaped profile, forming a pocket for the magnetic head below the carrier body and extends beyond the tip of the carrier body, where the second piece of shielding material completes an annular shielding ring around the end of the magnetic head. This shielding is particularly useful for an after-check playback head used during recording to check on the quality of the recorded signals.

Rotary magnetic head tape-scanning device with heads protected from

Magnetic tape recorder with shielding device for contact-free signal

A strip of easily magnetizable material of low remanence, having magnetic properties equal to or better than those of the core of the magnetic heads on a revolving headwheel of a video tape machine is provided as a magnetic shunt for each head, disposed in the neighborhood of the core gap, but spaced therefrom at a distance much greater than the gap width, for reducing the spread of stray flux when the head is used for recording and intercepting stray flux from other heads when the head is in the playback mode. Among the many ways in which the shunt can be provided are individual bridge strip mounted on the headwheel to bridge over each head laterally, a horseshoe-shaped strip covering the annular gap in which the headwheel revolves for the portions of that gap over which the tape passes, but spaced away from the tape, and strips mounted on the stationary guide drums or embedded in the headwheel periphery. The reduction and interception of stray flux is of important advantage when a tape reading head is in operation at the same time as a recording head on the same headwheel.

Growing community of inventors

Gross-Zimmern, Germany

Hartmut Willmann