Hitachi, Ltd.

Kuniaki Hirayama

Kenmei Masuda

Toshihiko Imachi

Yoshio Uemura

Atsushi Inoue

Hidekazu Takeda

Kiyokazu Watanabe

Hiroo Okamoto

Nobuo Masuoka

Hideo Nishijima

Nobutaka Amada

Yoshiharu Yamashita

Hisahiro Miki

Makoto Ibe

Noboru Katohno

Hideo Zama

Shinya Fujimori

Fukuyasu Abe

Kenkichi Inada

Seiji Ono

Hitoshi Odashima

Hiromichi Hiramatsu

Toshio Tsuchiya

Hideki Maruyama

Toshio Ohji

Masanori Kochi

Akihiro Nakajima

Kiyoshi Yamamuro

Eijiro Tazawa

Masahiko Fujishiro

A magnetic recording and/or reproducing apparatus having a plurality of recording/reproducing modes, such as a long-time recording/reproducing mode and a high rate recording/reproducing mode for digital signals, is intended to form an ideal recording pattern for any head configuration. The apparatus includes magnetic heads,and,having positive/negative azimuth angles and which are opposed to each other by 180&deg;; magnetic heads,and,having positive azimuth angles and which are opposed to each other by 180&deg;; and magnetic heads,and,having negative azimuth angles and which are opposed to each other by 180&deg;; wherein recording/reproducing is performed by using the magnetic heads,and,in a standard recording/reproducing mode; by using the magnetic heads,and,in a high rate recording/reproducing mode; by using the magnetic heads,and,in a long-time recording/reproducing mode which is twice as long as the standard mode; and by using the magnetic heads,and,in a long-time recording/reproducing mode which is N times (N; integer being 3 or more) as long as the standard mode.

Magnetic recording and/or reproducing apparatus

An arrangement is designed to achieve satisfactory tape contact by setting a specific ratio for the width of a drum window and the head length of a double azimuth head. The head length L is defined as the distance from the front end of the preceding head to the back end of the succeeding head. When the drum window width W is defined as the distance of the drum window in the rotary direction, the preceding head and the succeeding head are arranged within the drum window to satisfy the relation 1.15 L.ltoreq.W.ltoreq.1.28 L. When the space S1 is defined as the distance from the front end of the preceding head to the front end of the drum window, and the space S2 is defined as the distance from the back end of the succeeding head to the back end of the drum window, the preceding head and the succeeding head are arranged within the drum window to satisfy the relation 0.075 L.ltoreq.S1.ltoreq.0.14 L and 0.075 L.ltoreq.S2.ltoreq.0.14 L. According to this arrangement, the magnetic tape intrudes preferably into the space between the double azimuth head and the drum window. The magnetic tape envelopes and contacts the head surface, so that the tendency for a spacing to occur between the head and the tape is suppressed. The reproducing output is increased and stabilized in this way.

Rotary drum equipment and recording/reproducing equipment using the same

Disclosed in an arrangement to achieve satisfactory head contact by increasing contact face pressure at a head gap and to reduce the change in time of head contact performance in a double azimuth head. Heads in a portion in which a tape is slid are respectively constructed with each head having two different arcs with a radius of curvature R1 in a first area which includes a gap, and with a radius of curvature R2 in a second area which is adjacent to the first area. A transition portion P for transitioning an arc with the radius of curvature R1 and an arc with the radius of curvature R2 is located in the direction of its adjacent head based upon a contact point Q on R1 of a common tangent drawn from an arc forming a periphery of a rotating drum to a circle formed by R1. The relationship between the radiuses of curvature in two areas is set to R1&gt;R2. As the area in which a tape is in contact can be reduced, contact face pressure by the tape on a gap can be increased, satisfactory head contact can be obtained and as a contact area with a tape is wide to some extent, a change in time of contact performance can be reduced.

Rotary head and recording/reading apparatus provided with rotary head

In a rotary head drum of a recording/reproduction apparatus, for smoothly holding a magnetic tape over a guide step provided on a lower drum to guide the magnetic tape, part of a chamfer formed in the guide step is formed as a large chamfer in which a chamfered amount is larger than that of the remaining part of the chamfer. With the provision of the large chamfer, even if the lower edge of the magnetic tape deviates from the guide step when the tape is wound over or unwound from the drum, damages of the magnetic tape can be prevented. Therefore, the position and attitude control of tape withdrawing members can be greatly simplified and the magnetic tape can always run stably while being restricted in its position by the guide step. In the process of machining a tape running surface on the drum, by increasing the feed distance of a blade in the part of the chamfer where the large chamfer is to be formed by chamfering the guide step with a large chamfered amount, in comparison with the feed distance set in the remaining part of the chamfer, the large chamfer and the small chamfer can be both machined at the same time, resulting in simplified machining steps.

Tape guide structure of rotary head drum in recording/reproduction

A rotary magnetic recording and reproducing apparatus includes a stationary cylinder formed on a lower portion of an outer peripheral surface thereof with a guide lead for guiding a lower edge of a magnetic tape and defining a tape running face on an upper portion of the outer peripheral surface thereof, a first bulge portion formed on an upper edge portion of the tape running face of the stationary cylinder on a tape leaving side of the upper edge portion of the tape running face and a second bulge portion which is smaller in height than the first bulge portion and formed on the upper edge portion of the tape running face on the tape leaving side thereof and in the vicinity of the first bulge portion on a tape incoming side of the first bulge portion. The first bulge portion serves to relax shock or vibration of a magnetic tape leaving the magnetic head and the second bulge portion serves to improve 'head-touch' of the magnetic tape.

Rotary magnetic head cylinder device for reduced vibration and proper

A brushless motor includes a minimum number of parts and is assembled easily. A molded, substantially annular plastic permanent magnet on a rotor is magnetized in axially opposite directions alternatively such that a plurality of pairs of S and N poles are formed alternatively. The substantially annular permanent magnet includes an annular portion associated with air-core coils provided on a stator for generating a driving torque for the rotor and associated with a frequency signal generating circuit pattern provided on the stator for generating an electric signal indicative of a rotor speed and a protruded portion protruding from an outer peripheral side surface of the annular portion and associated with a rotor position detecting means provided on the stator for generating an electric signal indicative of a rotor position. A boundary line between an S and N pole of one of the plural pole pairs passes through the protruded portion. Lead portions for connecting terminals of the frequency signal generating circuit pattern to external circuits are formed such that they are overlapped to prevent degradation of frequency signal generator characteristics.

Brushless motor

A coil mounting method and apparatus is disclosed, for example, for mounting coils to the inner periphery of a cylindrical core in assembling a cylindrical rotary transformer of a VTR cylinder. A wire is wound round the outer periphery of a coil holding jig that is capable of opening and closing in a radial direction. After the coil is formed, the coil holding jig is inserted into a cylindrical article and opened radially to have the coil fitted in a coil groove formed in the inner periphery of the cylindrical article. The mounting of the coil to the inner periphery of a cylindrical article can be done in a short time through a reduced number of steps.

Method and apparatus for mounting coils inside a hollow cylindrical

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Hitachinaka, Japan

Kuniaki Hirayama