A tape guide device of a rotary head type video tape recorder of the helical scanning system including a shoulder portion formed on an outer circumferential surface of a lower stationary cylindrical portion cooperating with an upper rotary cylindrical portion and constituting a head cylindrical drum for guiding a magnetic tape. The shoulder portion has, in a section thereof with which the magnetic tape is not brought into contact, a configuration consisting of a plurality of parabolic lines connected to one another. Alternatively, the offset portion may have a configuration consisting of curves which are such that their second differential coordinates are continuous over the entire circumference of the head cylindrical drum with respect to the fixed coordinate system disposed on the outer circumferential surface of the head cylindrical drum, or the shoulder portion may have a configuration consisting of curves which are such that the absolute value of the maximum value of the second differential coefficients is not equal to the absolute value of the minimum value thereof.
A tape guide construction of a head drum of a video-cassette recorder comprising a circular wire fixedly engaged in a V-shaped groove formed at an outer peripheral surface of a lower drum of the head drum. A portion of the peripheral surface of the circular wire is disposed outside the V-shaped groove, whereby a tape is contacted at the lower edge thereof with and guided by the upper-protruded portion of the peripheral surface of the wire, during the travel thereof.
This invention relates to a rotary head assembly to be used for digital audio tape recorders (DAT) and the like. A magnetic tape can be made to run parallelly with a drum, the apparatus can be made small and light and the mechanism can be simplified.
A rotational magnetic head apparatus comprises a fixed drum, a rotational drum mounted rotatably about the same axis as that of the fixed drum and having an opening formed on the end surface of the rotational drum facing the fixed drum, and a magnetic head provided in the opening. A tape is wound partly around the outer periphery of the fixed and rotational drums so that the tape is caused to travel while the magnetic head slides on the magnetic tape. The position of the magnetic head is selected to be in the center between the opposing surface of the opening facing the fixed drum and the opposing surface of the fixed drum.
In a magnetic tape transport where the tape is guided by means of conventional guides, the tape may wander at the surface of the magnetic transducer between limits set by the mechanical parameters of the guides, e.g. the distance between upper and lower flanges of the guides. The present invention teaches tilting the face of the transducer contacting the tape by an angle of 0.5.degree. such that a component of force is generated which slides the tape along the transducer surface. The edge of the tape is then constrained to ride against a wear resistant shoulder mounted on the transducer surface, resulting in the tape being "locked" into position in relation to the magnetic transducer tracks.
