Abstract: A tone arm according to an embodiment includes: a first arm configured to rotate around a rotation shaft in a horizontal direction of a record; a second arm configured to rotate around a free fulcrum of the first arm as the first arm rotates; a motor configured to rotatably drive the first arm; and a controller configured to control a phase angle of the motor so that the second arm is disposed with a longitudinal axis thereof extends in a tangent direction of a groove of the record at a contact position of a stylus attached to a tip portion of the second arm and the groove of the record.

Abstract: There is provided a tool for efficiently cutting a face gear to be meshed with a helical gear. When a circular tooth thickness of a tooth tip of a cutting edge portion is represented as SatSC, a circular tooth thickness on a virtual outside diameter of a tooth profile of the helical gear in a cross-sectional view perpendicular to an axis is represented as Sat, a helix angle on the virtual outside diameter of the tooth profile of the helical gear in a cross-sectional view by a plane perpendicular to the axis is represented as ?a, and a face width of the cutting edge portion is represented as bsc, b SC ? s at - s atSC tan ? ? ? a is satisfied.

Abstract: There is provided a tool for efficiently cutting a face gear to be meshed with a helical gear. When a circular tooth thickness of a tooth tip of a cutting edge portion is represented as SatSC, a circular tooth thickness on a virtual outside diameter of a tooth profile of the helical gear in a cross-sectional view perpendicular to an axis is represented as Sat, a helix angle on the virtual outside diameter of the tooth profile of the helical gear in a cross-sectional view by a plane perpendicular to the axis is represented as ?a, and a face width of the cutting edge portion is represented as bsc, b SC ? s at - s atSC tan ? ? ? a is satisfied.

Abstract: A high-precision cog measuring instrument having as its operating axes an X-axis, a Y-axis, and a Z-axis, which are at right angles to each other, the device moving an object to be measured parallel to the X, Y, and Z axes, and in addition, rotating it around the Z-axis, while measuring the external shape of the object to be measured. The device including a main body, having a base, secured to an installation face where the high-precision cog system measuring instrument is to be installed; a Y-direction moving table, which is mounted on the base and can move in one horizontal direction; and an X-direction moving table, which supports a measuring element and can move in another horizontal direction at a right angle to the Y-direction moving table; a body for supporting the object to be measured having a section for supporting the object to be measured, which having a section for supporting the object to be measured, which can move in the Z-axial direction and rotate around the Z-axis.

Abstract: Disclosed is a high-precision cog measuring instrument having a constitution wherein warping is unlikely and not easily transmitted.

Abstract: In a non-contact type microdisplacement meter, two electrodes different in area are confronted with an object under measurement to form two electrostatic capacitances between the object and the electrodes, and the capacitances are coupled to two oscillator circuits, so that a displacement signal is provided as the frequency difference between the oscillator circuit, thereby to measure the very small displacement of the object.

Abstract: In a microdisplacement detector adapted to obtain a frequency signal corresponding to a microdisplacement of a feeler from two frequency signals which are provided by a movable electrode connected to the feeler and a pair of stationary electrodes disposed on both sides of the movable electrode, auxiliary stationary electrodes are provided for the aforementioned stationary electrodes so as to correct the capacitance variation characteristics of the differential capacitors which are formed by the stationary electrodes and the movable electrode, thereby to increase the range of measurement.

Abstract: A rotation angle detecting device with a pair of variable capacitors which are formed with a rotating object, i.e. a movable electrode, and two stationary electrodes disposed around the rotating object, so that the capacitors operate in a differential mode. Alternatively, the central electrode can be stationary while the two outer electrodes move with the rotating object. The capacitors are combined with oscillators, so that a signal varying with the rotation of the rotating object is provided by obtaining the difference between the output frequencies of the oscillators.

Abstract: A linear-moving type displacement detector has a movable electrode disposed between a pair of stationary electrodes such a manner that the electrodes are in parallel with one another, thus forming a pair of variable capacitors. The movable electrode is movable in a direction forming an angle with the stationary electrodes while being kept parallel with the stationary electrodes, so that one of the capacitances of the two capacitors is increased with the movement of the movable electrode, while the other is decreased, and vice versa. The capacitors are coupled to oscillators, the output frequencies of the oscillators are mixed in a mixer, to provide the difference frequency therebetween, or some analogous signal which is responsive to the difference frequency. The difference frequency or the analogous signal is utilized for displacement measurement.

Abstract: A device for measuring the amount of rotation of a rotating object is provided with a sensor unit made up of the rotating object and stationary members arranged to form two pairs of capacitors therebetween. The confronting surfaces of the rotating object and stationary members are graduated with gear-like cuts so that while the capacitances of two of two pairs of capacitors are maximum, the capacitances of the other capacitors are minimum. The device further comprises a pair of oscillators coupled to the two pairs of capacitors, and a mixer connected to the oscillators so that the difference in capacitance between the capacitors is obtained as the difference in frequency, which is processed to provide the amount of movement of the moving object.

Abstract: A device for measuring the amount of movement of a straightly moving object is provided with a sensor unit made up of the straightly moving object and stationary members arranged to form two pairs of capacitors therebetween. The confronting surfaces of the moving object and stationary members are graduated with gear-like cuts so that while the capacitances of two of the capacitors are maximum, the capacitance of the other capacitors are minimum. The device further comprises a pair of oscillators coupled to the two pairs of capacitors, and a mixer connected to the oscillators so that the difference in capacitance between the capacitors is obtained as the difference in frequency, which is processed to provide the amount of movement of the moving object.

Abstract: In a face gear assembly comprising a face gear and a pinion engaged therewith, the crest or top land of each tooth of the face gear is so formed as to touch the root surface or bottom land between two adjoining teeth of the pinion which are in mesh with the tooth, whereby the mutual engaging relationship of the face gear and the pinion can be regularly maintained.

Abstract: A device for measuring the amount of movement of a moving object is provided with a sensor unit made up of the moving object and stationary members arranged to form two capacitors therebetween. The confronting surfaces of the moving object and stationary members are graduated with gear-like cuts so that while the capacitance of one capacitor is maximum, the capacitance of the other capacitor is minimum. The device further comprises a pair of oscillators coupled to the two capacitors, and a mixer connected to the oscillators so that the difference in capacitance between the capacitors is obtained as the difference in frequency, which is processed to provide the amount of movement of the moving object.

Abstract: A minute change detecting system comprises sensor means which changes its electrical constant according to a physical change of an object under measurement to affect the oscillation frequency of at least one of two high-frequency oscillators, and mixer means for producing a beat frequency signal from the output oscillation frequencies of the two oscillators, thereby to detect the physical change.