Abstract: The object of the present invention is to provide a bolt, the axial force of which can be measured by a supersonic wave, or the like, with high accuracy and which can be manufactured in a shortened process. A bolt 1 having an angular polygonal shaped bolt head 2 is provided in the present invention. A recess 4 is formed on the bolt head 2 and a projection 5 having a plane upper face 6 is formed on the inner side of the recess 4, and at the end of the bolt shaft 3, a plane end face 8 is formed, and a wall, the outside of which being a C-face part is formed around the plane end face 8.

Abstract: The object of the present invention is to provide a bolt, the axial force of which can be measured by a supersonic wave, or the like, with high accuracy and which can be manufactured in a shortened process. A bolt 1 having an angular polygonal shaped bolt head 2 is provided in the present invention. A recess 4 is formed on the bolt head 2 and a projection 5 having a plane upper face 6 is formed on the inner side of the recess 4, and at the end of the bolt shaft 3, a plane end face 8 is formed, and a wall, the outside of which being a C-face part is formed around the plane end face 8.

Abstract: Within the housing of a flexible disc apparatus, a lead screw is rotatably laid along one side of the housing outside of a disc cartridge accommodation space, the lead screw piercing through bearing holes formed in a guide block from which two carriage arms are extending into the accommodation space, and carrying respectively thereon reading heads for picking up signals from a disc in a flexible disc cartridge loaded in the accommodation space, the distal end of the lower carriage arm is slidably engaged with a guide plate while the guide block and the lead screw are engaged with each other through the intermediary of a lead pin fixed to the guide block; thereby when the lead screw is rotated by a rotary drive mechanism, the guide block and upper and lower carriage arms is pitch-fed, and as a result, the reading heads are fed radially of the disc on the upper and lower surfaces thereof.

Abstract: A short cylindrical and thin sleeve bearing including a radial bearing portion of a dynamic pressure type on which grooves are formed is worked with high accuracy. Grooves are formed on an inner peripheral surface of a blank by a groove forming tool. Raised deformations generated on the inner peripheral surface as a result of this groove forming are removed by ball sizing of passing a steel ball on the inner peripheral surface. Further, by a roller burnishing tool, the cylindrical bore of the bearing is finished to have a predetermined diameter, and simultaneously, specular finish of the inner peripheral surface is effected.

Abstract: In a driving apparatus for a magnetic head, a steel band is connected to a head carriage along first and second faces of the head carriage and operatively wound around a capstan at a side of the second face to give linear motions to the head carriage in response to rotation of the capstan. A part of the steel band is pressed by a spring into a recess formed on the first face when is perpendicular to directions of the linear motions of the head carriage.

Abstract: In a magnetic disk apparatus, when a magnetic disk cartridge (56) is insrted in a cartridge holder (47), the front edge of the cartridge pushes a pin (42) and turns a trigger lever (41) to allow a slider (32) slides on a base plate (26) towards a front panel (53) by forces of springs (39a, 39b), thereby the cartridge holder (47) is brought down on the base plate (26) and a driving roller (224a) engages in a hole (205) of the magnetic disk cartridge (56) to drive it; the apparatus having only one trigger lever (41), the insertion of the cartridge (56) is smooth.

Abstract: A magnetic disk apparatus with a driving roller to engage a hole on a metal core of a disk cartridge to thereby drive the cartridge. The shaft of the apparatus has three different diametered portions to respectively engage the spring on which the driving roller is attached and a yoke structure with a permanent magnet and the shaft hole of the metal core of the cartridge.