Head drum assembly with electrical noise shield

Abstract

In a head drum assembly for a video tape recording and/or reproducing apparatus provided with stationary and rotary drum members for guiding a magnetic tape at their peripheries while video signals are recorded on, or reproduced from the tape by means of a magnetic head or heads carried by the rotary drum member and extending into a gap defined between the peripheral surfaces of the drum members; the rotary drum member, and hence the head or heads carried thereby, is driven by a D.C. motor disposed coaxially in respect to the drum members and having its shaft directly coupled to the rotary drum member, the signals being recorded or reproduced are transmitted by a signal transformer including nested annular stationary and rotary cores fixed to, and coaxial with the stationary and rotary drum members, respectively, and carrying confronting stationary and rotary windings which are respectively connected to signal leads extending from the stationary drum member and to the head or heads, and such signal transformer is shielded in respect to electrostatic and electromagnetic noise generated by the adjacent D.C. motor. The shielding for the signal transformer desirably includes a conductive metallic shield, for example, of a material of high magnetic permeability with a conductive metal layer or coating thereon, or of a conductive metal paint, which extends about at least the outer surface of the stationary core within which the rotary core is nested. Further, a conductive metallic shield is preferably provided on a wall of the stationary drum member which extends radially between the signal transformer and the D.C. motor and also about the latter.