VARIABLE BULGE DEVICE OF ROTARY HEAD DRUM

摘要

The bulge variable system to be used for a magnetic record reproduction unit is composed of an elastic rubber film(22) that is protruded according to the kind of tape and the rotational speed of the head drum(H), hydraulic fluid(23) to be charged in the elastic rubber film and the swelling agent(22a) of the hydraulic fluid that has the variable bulge(22a) protruded. When the hydraulic fluid(23) inside the rubber film expands the variable bulge(22a) is protruded thru the bulge hole(21) of the hub drum(11) up to the fixed hight. Conversely if the hydraulic fluid(23) shrinks, the amount of the protrusion of the variable bulge(22a) decreases.