Abstract: A numerical control apparatus is provided for controlling a position of a feed shaft in relation to a rotational angle of a main shaft of a machine tool. A value denoting the actual position of the feed shaft is subtracted from a positional command value to obtain a positional deviation value. The positional command value is one of a plurality of prestored values corresponding to a given rotational position of the main shaft. The positional deviation values for a single rotation of the main shaft are stored in a data table and displayed on a display device. Another data table having a plurality of correction values stored therein is provided. Each of the plurality of correction values stored in the correction value data table corresponds to a given rotational position of the main shaft. For each rotational position of the main shaft, the positional deviation value and a corresponding correction value are added together to obtain a corrected deviation value.

Abstract: An averaged diffraction moire position detector has a pair of diffraction gratings. One of the gratings has two grating portions arranged with an offset of half a pitch of the transit portions and the non-transit portions for light. The intensities of light passing through respective grating portions are added to cancel any error component is displacement signals produced when two parts of, for example, a machine tool move. Another averaged diffraction moire position detector uses offset in phase of respective error components contained in the diffracted light of plus and minus of the same number-order. Thus, the intensities of respective diffracted light are added to cancel respective error components, resulting in correct displacement signals being produced.

Abstract: An optical encoder includes a light source for emitting coherent parallel light and a scale having a grating track for defracting parallel light emitted from the light source. The grating track of the scale includes a plurality of linear adjacent gratings extending in a lengthwise direction. Each of the gratings extends in a widthwise direction direction to define a pitch of the grating. Each grating includes a non-transmitting portion and an adjacent transmitting portion extending in lengthwise direction. The aperture ratio defined by the ratio between a width of the transmitting portion and the pitch of each grating is substantially constant for each of the gratings along the grating track. However, the pitch of each of the gratings of the grating track varies along the grating track. A light spot positioning detector is provided for receiving positive and negative defracted light beams of a same order defracted from a grating track for determining a position of the scale.

Abstract: In order to detect positions, an optical encoder utilizes the phenomenon that the ratio in intensities of diffracted light beams of different orders change depending on the patterns of aperture ratios in one pitch of a grating on the scale, and that the distance between the positive and the negative diffracted light beams of the same order vary depending on the patterns of the grating pitch on the scale, or that the light spots of the positive and the negative diffracted light beams of the same order move (rotate) depending on the patterns of the grating line direction. Therefore, this optical encoder is free from the adverse influence of fluctuations in the amount of coherent light illuminated from the light source to thereby enable precise positional detection.

Abstract: In a method for processing animated graphic in which a graphic symbol is displayed on a displaying unit on the basis of data preliminarily set in a video RAM and the displayed graphic symbol is totally shifted by a predetermined amount, the graphic symbol to be shifted is initially described in an original graphics storing area and a graphic symbol transfer area is provided so as to include the graphic symbol initially described in the original graphics storing area and includes a non-display area at the outer periphery thereof. The data corresponding to the transfer area is then transferred into the video RAM the transferred data including the sizes or dimensions and the coordinate of the reference point of the transfer area.

Abstract: In the prior art, a DC motor is often utilized for controlling speed of servomechanism for its simpleness in operation and excellent control. However, as a DC motor is equipped with brushes and commutators, it inconveniently requires periodical maintenance and inspections in order to keep normal operation. As electric semiconductors such as power transistors along with control technology have made a remarkable progress in recent years, a demand for motors which do not need maintenance is keenly felt. Studies have been conducted on control by DC motors and some have been put into practice. According to this invention, there is provided a synchronous motor which has a small field loss and which does not need slip rings or rotary transformers. Further, there is provided synchronous motor which can be simply constructed at a low cost without using a permanent magnet as a rotor and which can realize a larger capacity, and provided a control unit for the synchronous motor.

Abstract: A graphics, such as a shop drawing of a workpiece worked by a machine tool, is inputted as working data in an automatic programming function in accordance with the natural graphic recognition order for an operator, and the system therefor includes the steps of first designating the shape of a basic graphics of the workpiece, and then designating sizes of the basic graphics, and finally designating the shape and sizes of auxiliary graphics of the workpiece.

Abstract: An automatic apparatus for an NC machine tool which automatically changes tools, automatically measures the tool size and automatically compensates for the amount of abrasion without stopping for indexing and positioning. The apparatus can automatically and easily measure and compensate for variations in the diameter of cutters in an end mill, a boring machine, etc.

Abstract: When a load current on a motor was to be monitored, all the digital values of the load current at the model operation were conveniently memorized in a memory to be compared with the load current value of the actual operation. The capacity of the memory therefore became enormous, presenting a problem. This invention enables to memorize a load current of a motor at the model operation in terms of the dimensional difference from a reference value and of duration of time. Thanks to such an arrangement, the volume of stored data can be reduced to minimize the capacity of the memory, thereby facilitating the comparison process of data at the time of actual operation.

Abstract: In machine tools it is necessary to monitor the track of a cutter tip on a tool post. A predetermined tolerance scope is given to sampling positions during the model cutting, and only the data of the points and distance defining the tolerance scope is stored. During the actual cutting, a determination is made as to whether or not a sampling position is within the tolerance scope and the track is thereby securely monitored.

Abstract: This invention concerns an improvement for the structure of a rotor attachment in a permanent magnet type synchronous motor. This invention can effectively prevent axial displacement or peeling off of the magnets which might otherwise be caused by insufficient adhesion or deterioration of adhesives by the unique structure of attaching magnets to the rotor shaft as side plates having grooves are fixed to both sides of magnets adhered to a shaft to engage with at least one end face of magnets and the outer peripheries of the side plates and the magnets are wound with non-magnetic fibers for securing, thereby greatly enhancing the reliability of the motor.