Kabushiki Kaisha Kobe Seiko Sho

Susumu Takada

Heijiro Kawakami

Yasunobu Kawaguchi

Mamoru Murahashi

Kozo Katsube

A coil of tapered wire for forming coil springs, formed by winding substantially in concentric loops a quench-hardened and tempered tapered wire having a successive arrangement of tapered wire segments each consisting of a thick section, two thin sections and two tapered sections connecting the thin sections to the opposite ends of the thick section, respectively. The tapered wire is subjected to a preforming action immediately before being wound in loops on a winding drum, to form plastic bends in the thick sections and plastic bends of a radius of curvature greater than that of the plastic bends in the thick sections so that the tapered wire is wound in substantially uniform, concentric circular loops on a winding drum. When the tapered wire is unwound from the coil and is subjected to a straightening process of a fixed straightening arrangement of a series of straightener rollers before being coiled in tapered wire coil springs on a coil spring forming mill, the thick sections undergo a straightening action greater than that acts on the thin sections, so that which the tapered wire unwound from the coil of tapered wire is straightened in a substantially straight tapered wire and thereby the tapered wire is coiled in tapered wire coil springs having a correct size and a uniform shape.

Coil of tapered wire

A tapered rod producing process by which a tapered rod having a profile very near to an aimed profile can be produced with high accuracy. According to the process, during working of a wire diameter gradually decreasing portion of a tapered rod in which the diameter of a stock gradually decreases in a feeding direction of the stock, the drawing length of the stock from starting to ending of acceleration of variable speed feeding mechanism is made greater than predetermined length of the wire diameter gradually decreasing portion, and during working of a wire diameter gradually increasing portion in which the diameter of the stock gradually increases, the drawing length of the stock from starting to completion of deceleration of the variable speed feeding mechanism is made smaller than an a desired length of the wire diameter gradually increasing portion of the tapered rod.

Growing community of inventors

Kobe, Japan

Susumu Takada