Rotary head deflection apparatus

Claim 2

A rotary head deflection apparatus comprising: first and second movable members (45) supported on a rotary member (1) and capable of being displaced in a direction parallel to the axis of rotation (A) of said rotary member (1), and carrying magnetic heads (2,3) and magnets (6a, 6b, 7a, 7b) respectively; a stator (9) disposed adjacent the axis of rotation (A) of or on a concentric circle with said rotary member (1), and wound with at least first and second driving coils (Sa,8b) having predetermined gaps with respect to surfaces of said magnets (6a,6b,7a,7b) respectively; and a control circuit (Figure 4) for feeding a control current to said first and second driving coils (8a,8b) whereby to cause said magnetic heads (2,3) to deflect corresponding to said control current and in a direction parallel to the axis of rotation of said rotary member (1).

Claim 3

A rotary head deflection apparatus according to claim 1, wherein one of said first and second movable members (4,5) on which said magnetic heads (2,3) and said magnets (6a,6b,7a,7b) are disposed, is so constructed that the surfaces of said magnets on said one member opposite to said first and second driving coils (8a,8b) are homopolar to each other, the other of said movable members (4,5) being so constructed that the surfaces of said magnets on said other member are heteropolar to each other.

Claim 4

A rotary head deflection apparatus as set forth in claim 1 or 2, wherein said first and second movable members (4,5) are mounted on said rotary member (1) through resilient support members (11,12), and the surfaces of said magnets fixed to said movable members are adapted to be opposite to said first and second driving coils (5a,8b) wound onto said stator (9), keeping the predetermined gaps with respect to said first and second driving coils (8a,8b).

Claim 5

A rotary head deflection apparatus as set forth in claim 1,2 or 3, wherein the natural frequency of each of said movable members (4.5) supported by said elastic support members (11,12) is set in proximity to the rotary frequency of said rotary member (1).

Claim 6

A rotary head deflection apparatus as set forth in claim 1,2,3, or 4, wherein said first and second movable members (4,5) are mounted on said rotary member through two resilient plate-like-shaped support members (11,12) fixed to the upper and lower end faces of said movable members respectively, thereby being supported by said rotary member (1) for displacement in a direction parallel to the axis of rotation of said rotary member (1).

Claim 7

A rotary head deflection apparatus as set forth in any one of the preceding claims, wherein said magnets (6a,6b,7a,7b) are magnetised on the same magnetic material respectively.

Claim 8

A rotary head deflection apparatus as set forth in any one of the preceding claims, wherein said control circuit for feeding a control current to said first and second driving coils comprises: first and second drive circuits for feeding to said first and second driving coils control currents corresponding to an input of said control circuit; an adder connected at the output side with one of said first and second drive circuits and given two inputs of two system electric signals including the positional change informations of said first and second magnetic heads; and a subtracter connected at the output side with the other of said first and second drive circuits and given two inputs of two system electric signals including the positional change informations of said first and second magnetic heads, so that said first and second magnetic heads are adapted to deflect independently of each other in the direction of the axis of rotation of said rotary member.