Abstract: A method and apparatus for manufacturing a spark plug, the spark plug being defined herein, the method including a center electrode position measuring step of measuring an X-directional position of the front end of the center electrode; a regulation member positioning step of positioning an X-directional position of a regulation member based on the X-directional position of the front end of the center electrode measured in the center electrode position measuring step, the regulation member regulating an X-directional position of a front end surface of the ground electrode when the ground electrode is pressed and bent in a Y direction; and a gap forming step of using the regulation member to regulate the X-directional position of the front end surface of the ground electrode while pressing and bending the ground electrode in the Y direction so as to form the spark discharge gap; wherein: the X direction and the Y direction are as defined herein.

Abstract: Protrudent matters caused by connecting metallic materials are detected with high precision and in turn offer products of high quality, and an increase of yield. The invention sets an allowable range and a non-allowable range around an outside outline (an outline of the work to be detected) of the connected work member on the basis of a shape of an outline of a reference work member (a reference outline) becoming a reference of the connected work member in order to judge presence or absence of the outline of the work to be detected in the non-allowable range, said allowable range allowing the existence of the outline of the work to be detected, and said non-allowable range not allowing the existence of the outline of the reference work.

Abstract: A method and apparatus for manufacturing a spark plug, the spark plug being defined herein, the method including a center electrode position measuring step of measuring an X-directional position of the front end of the center electrode; a regulation member positioning step of positioning an X-directional position of a regulation member based on the X-directional position of the front end of the center electrode measured in the center electrode position measuring step, the regulation member regulating an X-directional position of a front end surface of the ground electrode when the ground electrode is pressed and bent in a Y direction; and a gap forming step of using the regulation member to regulate the X-directional position of the front end surface of the ground electrode while pressing and bending the ground electrode in the Y direction so as to form the spark discharge gap; wherein: the X direction and the Y direction are as defined herein.

Abstract: A method for making a spark plug is provided. The method comprises the steps of, for adjustment of a spark gap, provisionally pressing a ground electrode toward a leading end surface of a center electrode and thereby decreasing the spark gap to a predetermined value larger than a final target gap gt, after the step of provisionally pressing the ground electrode, performing an adjustment bending process for eliminating an eccentricity ? of the ground electrode in the widthwise direction thereof with respect to a target position, after the step of performing the adjustment bending process, measuring a spark gap g1 and measuring a difference (g1?gt) between the measured spark gap g1 and the final target gap gt, and pressing the ground electrode toward the center electrode when the difference (g1?gt) is positive. An apparatus for carrying out the method is also provided.

Abstract: A problem to be solved by the invention is to provide a method of detecting protrudent matters adhered to surfaces of metallic materials when connecting them, and a method of making spark plugs using the same, enabling to detect at high precision occurrence of the protrudent adhered matters caused by connecting metallic materials, and in turn offer products of high quality, and effectively accomplish increase of yield. The invention sets an allowable range and a non-allowable range around an outside outline (an outline of the work to be detected) of the connected work member on the basis of a shape of an outline of a reference work member (a reference outline) becoming a reference of the connected work member in order to judge presence or absence of the outline of the work to be detected in the non-allowable range, said allowable range allowing the existence of the outline of the work to be detected, and said non-allowable range not allowing the existence of the outline of the reference work.

Abstract: A method for manufacturing a spark plug, which includes photographing a spark gap as to detect the edges of a center and ground electrode and performing a predetermined treatment on the basis of image information obtained from the photographing step. Also disclosed is an apparatus for carrying out the method. In performing the photographing step, an illumination device 200 is disposed opposite a tip portion of a spark plug, in which a spark gap is to be formed, such that illumination rays pass through the spark gap. A camera 4, which is disposed opposite the illumination device 200 with respect to the tip portion of the spark plug, photographs the spark gap formed between a center electrode W1 and a ground electrode W2.

Abstract: A method for making a spark plug is provided. The method comprises the steps of, for adjustment of a spark gap, provisionally pressing a ground electrode toward a leading end surface of a center electrode and thereby decreasing the spark gap to a predetermined value larger than a final target gap gt, after the step of provisionally pressing the ground electrode, performing an adjustment bending process for eliminating an eccentricity &dgr; of the ground electrode in the widthwise direction thereof with respect to a target position, after the step of performing the adjustment bending process, measuring a spark gap g1 and measuring a difference (g1−gt) between the measured spark gap g1 and the final target gap gt, and pressing the ground electrode toward the center electrode when the difference (g1−gt) is positive. An apparatus for carrying out the method is also provided.

Abstract: A method for manufacturing a spark plug that can calculate, in measurement of a gap, an accurate gap regardless of inclination of a workpiece (a spark plug) with respect to a measurement device and can manufacture the spark plug at high accuracy as well. Also disclosed is an apparatus for carrying out the same. A plurality of measurement points are determined on the outline (tip edge E2) of a ground electrode spark gap definition portion of a ground electrode W2 facing a spark gap and on the outline (tip edge E1) of a center electrode spark gap definition portion of a center electrode W1. The measurement points represent the outlines of the respective spark gap definition portions. A single measurement point on the outline of one spark gap definition portion is selected as a reference point. A measurement point on the outline of the other spark gap definition portion is found such that the distance between the measurement point and the reference point is the shortest.

Abstract: A method for manufacturing a spark plug that can calculate, in measurement of a gap, an accurate gap regardless of inclination of a workpiece (a spark plug) with respect to a measurement device and can manufacture the spark plug at high accuracy as well. Also disclosed is an apparatus for carrying out the same. A plurality of measurement points are determined on the outline (tip edge E2) of a ground electrode spark gap definition portion of a ground electrode W2 facing a spark gap and on the outline (tip edge E1) of a center electrode spark gap definition portion of a center electrode W1. The measurement points represent the outlines of the respective spark gap definition portions. A single measurement point on the outline of one spark gap definition portion is selected as a reference point. A measurement point on the outline of the other spark gap definition portion is found such that the distance between the measurement point and the reference point is the shortest.

Abstract: A method for manufacturing a spark plug, which includes photographing a spark gap as to detect the edges of a center and ground electrode and performing a predetermined treatment on the basis of image information obtained from the photographing step. Also disclosed is an apparatus for carrying out the method. In performing the photographing step, an illumination device 200 is disposed opposite a tip portion of a spark plug, in which a spark gap is to be formed, such that illumination rays pass through the spark gap. A camera 4, which is disposed opposite the illumination device 200 with respect to the tip portion of the spark plug, photographs the spark gap formed between a center electrode W1 and a ground electrode W2.