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:
Mar. 22, 1988
Filed:
Mar. 14, 1986
Richard M Dunham, Salisbury, NH (US);
Walker Magnetics Group, Inc., Worcester, MA (US);
Abstract
In the ion nitriding power supply disclosed herein, power to the discharge chamber is normally current-regulated by a pulse-width modulated current switching device effectively in series with a switching inverter which energizes the chamber, instantaneous current variations being smoothed by a series inductance which, together with the chamber, is shunted by a freewheeling diode. Incipient arcing is quickly extinguished by semiconductor switching devices incorporated in the inverter which, when energized simultaneously, shunt the chamber, instantaneous current limiting being provided by the series inductance. The shunt switching devices are triggered when the voltage across the discharge drops below a level indicative of the formation of an arc.