Abstract: An object of the present invention is to provide a center drum rotating type of rotary magnetic head drum apparatus, which improves an accuracy of alignment of an upper fixed drum, and easily executes a fine adjustment. In correspondence to the object mentioned above, a hole fitted to a shaft is provided at a position coaxial with an outer periphery of an upper fixed drum in an end surface portion of an upper portion of the upper fixed drum, the shaft is inserted to the hole, a slope of the end surface portion of the upper portion of the upper fixed drum is adjusted while being fixed by a male screw and a locking screw, and a fine adjustment is executed for aligning the upper fixed drum. In particular, an outer periphery of the upper fixed drum in an input side of the tape is slightly moved backward from an outer periphery of the upper fixed drum in an output side of the tape, with respect to an outer periphery of the lower fixed drum.

Abstract: 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.

Abstract: 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.

Abstract: 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>R2.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.