Abstract: A movable member is situated within a cylindrical member so as to be axially movable The movable member is supported by a magnetic bearing device in relation to the cylindrical member in a perfect non-contact manner. The cylindrical member and movable member are provided with an electromagnetic force generating mechanism for selectively applying an axial driving force to the movable member in a non-contact manner. The movable member is provided with an auxiliary plate having an inclined surface inclined with respect to the axis of the movable member. The axial position of the movable member is detected by the output of a detector which detects the distance between itself and the inclined surface. On the basis of the detected axial position and an objective position, the electromagnetic force generating mechanism is activated to set the axial position of the movable member.

Abstract: A non-linear control type magnetic bearing comprises a pair of electromagnets for magnetically attracting an object so as to permit it to be levitated therebetween, a current supply circuit for alternately supplying an excitation current to the pair of electromagnets, a circuit for generating a pair of current level signals corresponding to the levels of the currents through the respective electromagnets, a velocity sensor for generating a velocity signal corresponding to a velocity with which the object is moved, a difference circuit for generating a difference signal corresponding to a pair of current level signals, a differentiating circuit for differentiating the velocity signal to generate an acceleration signal corresponding to the acceleration rate of the object, an analog operating circuit for generating a position displacement signal corresponding to the position of displacement of the object by substituting a difference signal and acceleration signal into an equation of motion of the object, and a s

Abstract: An optical pickup assembly has a lens assembly movably supported in a magnetic gap of a yoke by flexible supporting members. Magnetic interaction between elements of the lens assembly and the yoke help center the lens assembly in the magnetic gap. Electromagnets move the lens assembly from the centered position. A light source, a collimator lens and a polarizing beam splitter are fixed with respect to the yoke.

Abstract: In a hydraulic apparatus, an operating oil delivered from a fixed delivery hydraulic pump is divided into two parts, one of which is discharged into an oil tank by passing through a serial circuit consisting of a normally open valve and an orifice and the other of which is supplied to a piston-cylinder means by passing through a parallel circuit consisting of a normally closed valve and a check valve. When the normally closed valve is closed and the normally open valve is gradually closed, the piston is raised while gradually increasing in velocity. On the other hand, when the normally open valve is totally opened to stop the piston and the normally closed valve is gradually opened, the piston is lowered while gradually increasing in velocity. When the valves are operated to cause the piston to move vertically, the impact applied thereto at the time when the valve opening is large is largely mitigated by using said orifice.

Abstract: In a hydraulic apparatus, operating oil delivered from a fixed delivery hydraulic pump is divided into two parts, one end of which is discharged into an oil tank by passing through a serial circuit of a normally open valve and an orifice and the other end of which is supplied to a piston-cylinder mechanism by passing through a parallel circuit of a normally closed valve and a check valve. When the normally closed valve is closed and the normally open valve is gradually closed, the piston is raised while gradually increasing in velocity. On the other hand, when the normally open valve is totally opened to stop the piston and the normally closed valve is gradually opened, the piston is lowered while gradually increasing in velocity. When the valves are operated to cause the piston to move vertically, the impact applied thereto at the time when the valve opening is large is largely mitigated by using the orifice.