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:
Sep. 10, 1996
Filed:
Aug. 23, 1995
Edward C Berdich, Downingtown, PA (US);
Wind Lock Corporation, Birdsboro, PA (US);
Abstract
A hand-held groover for forming grooves, bevels, etc. in architectural insulation board comprises a resistive cutting blade, a 25 KHz. oscillator, operated by full-wave rectified line current and connected to the cutting blade through a light-weight transformer. The oscillator delivers to the heating element a sequence of electrical pulses synchronized with the line current frequency, each having a duration of 1/120 second. Each pulse consists of plural oscillations at 25 KHz., so that the heating current in the blade is essentially an amplitude-modulated 25 KHz. current. The modulating pulses are selected from the continuous train of 120 Hz. pulses by an adjustable triggering circuit, to adjust the time interval between pulses and thereby control the temperature of the heating element.