A rotary head mounting device for mounting a rotary head obliquely on a chassis includes one or more oblique bases formed by outsert forming on the chassis. Each of the oblique bases has a mounting surface which is oblique to the chassis for mounting a rotary head thereon and a mounting hole for receiving a screw for fixing the rotary head which mounting hole is formed from the mounting surface into the oblique base vertically with respect to the mounting surface. The rotary head is fixed in its mounting portion to the mounting surface of the oblique bases by screwing the screw into each mounting hole through the mounting portion. The rotary head can be directly mounted on the oblique bases on the chassis without using a separate adaptor so that mounting of the rotary head on the chassis is facilitated. Besides, the mounting device can be made very simply and cheaply by outsert forming the mounting device simultaneously with outsert forming other parts on the chassis. In one aspect of the invention, positioning projections are provided on the oblique surfaces so that the rotary head can be mounted on the oblique bases with high accuracy without being affected by the accuracy of positions of the mounting holes.

For recording on, and reading of, a magnetic tape guided around a cylinder, there are several magnet heads arranged on a common circle diameter. The magnet heads revolve about a common axis extending obliquely with respect to the travel direction of the tape. The magnet heads interact with the tape through a slot-shaped aperture formed in the cylinder. For the purpose of achieving a very simple tape-guiding system, the tape is guided in a direction perpendicular to the cylinder longitudinal axis over a cylinder surface which, at least in its tape-guiding zone, and viewed in a section perpendicular to the cylinder longitudinal axis, corresponds at least approximately to a projection of the circular motion performed by the magnet heads in a direction perpendicular to the tape travel direction.

Parallelism between the track on magnetic tape and the path of the rotating head is dynamically adjusted and maintained by adjusting one or both of the entry or exit guides guiding the tape as it helically wraps a mandrel. The mandrel has two halves that flank the rotating head so that as the tape wraps the mandrel, the rotating head traverses the tape at an oblique angle. Skew error is represented by a lack of parallelism between the track on the tape and the path of the rotating head across the tape. The skew error may be corrected by laterally shifting either the entry or exit tape edge guide without distorting the track over a limited lateral range of movement by the guides. The entry and exit edge guides are continuouscompliant air-bearing guides. Similarly, the mandrel that supports the tape adjacent the rotating head is also air bearing.

A rotating head mandrel is contoured so that in cross-section the mandrel appears similar to the shape of an eyeball. Two mandrels are axially aligned for supporting a tape helically wrapped about the mandrels. Between the two mandrels is a rotor carrying a magnetic head. The magnetic tape helically wraps the two mandrels in the region of the rotor. The path of the rotating head relative to the tape is a transverse track at an acute angle to the longitudinal direction of the tape. The peak of the eyeball contour or cam shape contour of the mandrel is located at the entry and exit points of the tape as it helically wraps the mandrels. The peak gives the tape additional height relative to the rotating head and prevents the head from nicking the edge of the tape as it crosses the edges of the helically wrapped tape. The surfaces of the mandrels have holes through which air may be forced to provide a hydrostatic air bearing between the tape and the mandrels. The pattern of the holes on the mandrels is selected to support the tape in a uniform manner during helical wrap of the tape about the mandrels.