JPS57200928A - Rotary head type magnetic tape recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent a rotary head chip from breaking when an oscillation impact is applied, and to achieve the prevention of the entrance of external dust and an increase in inertia of rotation simultaneously, by srranging an annular projecting part on the head base plate of a rotary head structure. CONSTITUTION:On the surface of a head plate 20 which faces the reverse surface of an upper drurm 21 on the plate 20, a projection 20a is provided annularly in one body. The internal diameter of the upper drum 21 is reduced until it overlaps with the projection 20a and does not touch the head plate 20. Further, the clearance B between the top surface of the projection 20a and the reverse surface of the upper drum 21 is made less than the clearance A between the reverse surface of the upper drum 21 and the top surface of a rotary magnetic head chip and the projection and upper drum do not come into contact. Thus, the entrance of dust, etc., from a gap 22 is prevented and even if the falling down of the upper drum to the opposite side 21a due to the cantilever structure of a drum support 15 occurs, the projection 20a and the upper drum come into contact before the head chip breaks down. Further, the projection 20a increases inertia of rotation to reduce jitters.