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:
Nov. 16, 1982
Filed:
Dec. 17, 1979
Joseph R Keller, Harrisburg, PA (US);
AMP Incorporated, Harrisburg, PA (US);
Abstract
An induction heating apparatus for heating an electrically conductive workpiece, comprising a C-shaped core made of a material having a high magnetic permeability and having two closely opposed tapered ends, an exciting coil surrounding the core, and a circuit for supplying a periodic voltage to the coil so as to cause a varying magnetic field to be produced in the core and to efficiently focus a field of high flux density between its two ends. In one embodiment the core is made of ferrite, a capacitance is connected with the exciting coil to form a resonant circuit, and circuitry is provided for detecting the phase of the current flowing in the resonant circuit and for controlling the frequency and phase of the periodic voltage supplied to the resonant circuit so as to maintain the circuit in resonance. In other embodiments, one of the two ends of the core is mounted on a slidable ram portion, which can be moved toward and away from the other end of the core, and electrically insulating workholders can be mounted on each end of the core to hold a workpiece in place as the ends of the core are pushed toward each other.