Abstract: This invention relates to a vibration isolating bushing, for example, built into a suspension system, an inside diameter of one edge (4) of an inner cylinder (1) being made larger than that of the other edge (6). The outside diameter of the thinner edge (4) is enlarged by applying pressure with a pressure forming jig (26) to the thicker edge surface (25), with the thinner edge surface (20) of the inner cylinder (1) abutted on a base (23). After completion of enlargement of the outside diameter of the thinner edge (4), the outside diameter of the thicker edge (6) is enlarged by further pressure with the pressure forming jig (26), this process thus capable of enlarging the outside diameter of both edges (4), (6) with one continuous working step.

Abstract: This invention relates to a vibration isolating bushing, for example, built into a suspension system, an inside diameter of one edge (4) of an inner cylinder (1) being made larger than that of the other edge (6). The outside diameter of the thinner edge (4) is enlarged by applying pressure with a pressure forming jig(26) to the thicker edge surface (25), with the thinner edge surface (20) of the inner cylinder (1) abutted on a base (23). After completion of enlargement of the outside diameter of the thinner edge (4), the outside diameter of the thicker edge (6) is enlarged by further pressure with the pressure forming jig (26), this process thus capable of enlarging the outside diameter of both edges (4), (6) with one continuous working step.

Abstract: A sucker rod coupling pin comprises a hole into which the sucker rod is to be inserted, and has a plurality of annular depressions which surround the inner wall of the hole. As viewed crosswise, the annular depressions respectively have tapered surface portions arranged in series from the open end to the closed end of the coupling pin hole. The tapered surface portions whose cross sections progressively increase toward the closed end of the coupling pin hole have their respective lengths progressively shortened in relation to the preceding tapered portion, toward the closed end of the coupling pin hole, and the angle of inclination of the respective tapered surface portions progressively increases toward the closed end of the coupling pin hole.