The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 27, 1989
Filed:
Jun. 04, 1984
Daido Tokushuko Kabushiki Kaisha, Aichi, JP;
Abstract
Method for manufacturing a tapered rod for a coil spring from a metallic material of mainly steel in a linear state, by imparting heating to the same with a predetermined temperature gradient pattern in the axial direction thereof while or before pulling by tensile force the metallic material chucked at two axially distant points in either direction in a gradually decreasing or stepwise decreasing speed, until a desired tapered portion is formed. An apparatus preferably employed for this method comprises a pulling mechanism for chucking and pulling the material, an electric current supplying mechanism for supplying predetermined amount of current to the material between the two chucked points, a plurality of cooling units arranged axially along the material for positionwise cooling the material so as to make the temperature gradient thereon, a temperature detecting device for detecting the surface temperature of the material for feeding back the detected data to the current supplying mechanism, and a heating temperature controlling device for controlling the amount of the current flowed there.