1. Field of the Invention
The invention relates to an apparatus for magnetically recording and/or playing back wide-band signals, such as video signals, on a magnetic tape, and more particularly to an apparatus having a rotatable head disc on which is disposed a number of electromagnetic heads which are spaced at equal radial distances from the axis of rotation of the disc and which are uniformly spaced around the circumference of the disc, and a tape guide having concave guide members for guiding the magnetic tape in a locally transversely curved condition past a part of the circular path of said electromagnetic heads in a direction extending transversely of the plane of rotation of the head disc. 2. Description of the Prior Art
In known apparatus of this type, to obtain a transversely curved shape of the magnetic tape, a partial vacuum is produced between two concave guide members in a vacuum chamber, so that the tape is drawn into the curvature of the guide members. Therefore, it is necessary to provide such apparatus with a vacuum pump, which is connected to the vacuum chamber by suitable means.
Although the provision of a vacuum pump presents few problems in connection with large professional apparatus, which are used in broadcasting studios for example, the situation is different in the case of apparatus intended for domestic use. These latter apparatuses are mass-produced and are equipped with a different system for guiding the magnetic tape past the head disc. In such apparatus the magnetic tape is locally moved helically around a two-part cylindrical drum in which the head disc is rotatably mounted. A slot is provided between the two drum sections to allow the heads of the head disc, which pass through the slot, to write obliquely extending tracks on the magnetic tape. However, a drawback of this type of apparatus is that, for a number of reasons, the amount of information which can be stored on the magnetic tape is smaller than the amount that can be stored with an apparatus of the first type, in which the tracks are written transversely of the magnetic tape. Another drawback is that bringing the magnetic tape into contact with the drum, and maintaining it in contact, demands a intricate loop-shaped lace-up, as well as fairly intricate means for moving the tape from the disengaged position to the operating position and vice versa.