Guzik Technical Enterprises

Guided Medical Systems, Inc.

Cem Kilicci

Nahum E Guzik

Ufuk Karaaslan

Ilia M Bokchtein

Zev Galel

Henry Bourang

A magnetic head and disk tester includes a magnetic head which is selectively positioned relative to a rotatably mounted magnetic disk to accomplish testing of either of the head or disk or both. The magnetic head is secured to a carriage which is under electro-mechanical control, wherein displacement of the carriage causes a corresponding displacement of the head relative to the disk and, to some degree, may cause yaw in the carriage. Measurements of the linear position of a left and a right side of the carriage are detected, measured, and fed back to a control system. The control system responds to a difference between a desired command position and the actual position of each side of the carriage and causes actuators to adjust the position of each side of the carriage until the difference, and thereby the yaw, is substantially eliminated. Additionally, during a positioning operation, vibrations in the yaw direction are decreased, which decreases a corresponding settling time of the magnetic head.

Magnetic head and disk tester with yaw correction

A magnetic head and disk tester provides accurate positioning of a magnetic read-write head over a magnetic disk by means of a coarse positioning mechanism and a fine positioning mechanism. The coarse positioning mechanism includes a stepper motor, a lead screw, a nut, rear sliders and a housing. The fine positioning mechanism includes a piezoelectric actuator, slides and a carriage. The positioning displacements are along a linear axis, which lies on a horizontal plane. The carriage is connected to the housing via the fine positioning mechanism, which then moves the carriage with respect to the housing. Two pairs of linear encoders are mounted on the carriage about the axis and measure the position of the magnetic read-write head with respect to the magnetic disk. Each pair is mounted such that the pairs lie in separate horizontal planes. One linear encoder on each pair is mounted to the right of the magnetic read-write head and the other to the left of it, the magnetic read-write head being equal distances from the two linear encoders of each pair. The magnetic read-write head is mounted on the carriage with an offset from each pair of linear encoders in the vertical direction. Pitch during the fine positioning movement causes the head to move a different amount than that measured by any one of the pairs of linear encoders. By using both pairs of encoders, the amount of pitch is determined. A feedback circuit responsive to that determination causes the fine positioned to move the head to the correct pitch.

Magnetic head and disk tester with pitch correction

An improved fine positioning mechanism in a magnetic head/disk tester includes a primary position actuator and a primary body that supports a read/write head to be tested, and an auxiliary body and auxiliary actuator. Both actuators operate contemporaneously and in mutually opposite directions. The masses of both bodies and the stiffnesses of both actuators are selected so that a ratio of the stiffness of the actuator to the mass of the body in the primary system is equal to a ratio of the stiffness of the actuator to the mass in the auxiliary system. In addition, the masses of both bodies and the expansion coefficients of both actuators are selected so that a product of the mass of the body with the expansion coefficient of the actuator in the primary system is equal to a product of the mass of the body with the expansion coefficient of the actuator in the auxiliary system. In this manner, forces operating on both bodies are equal in magnitude and opposite in direction and therefore counterbalance each other when the same control voltage is applied to both actuators. This, in turn, eliminates or reduces vibrations in the slide supporting the actuators and therefore the head-positioning settling time is significantly reduced.

Apparatus and method for improving dynamic characteristics of a

A composite catheter is formed by the combination of a catheter body and a tubular member insertable or secured inside the catheter body. The tubular member contains a series of relatively rigid segments alternating with flexible, collapsible segments which permit the rigid segments to effectively stack against one another when the tubular member is compressed axially. The shape that results when the rigid segments are forced together differs from that of the shape memory of the catheter body in certain embodiments of the invention, and changing the tubular member from a relaxed condition to the compressed condition inside the catheter body can therefore cause a change in shape of the catheter body.

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San Francisco, CA, United States of America

Cem Kilicci