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:
Jul. 11, 2000
Filed:
Nov. 07, 1997
John Edward Pfeifer, Redding, CT (US);
James C Boda, Merrimac, WI (US);
David M Hoerr, Mazomanie, WI (US);
Fiskars Inc., Madison, WI (US);
Abstract
A portable power system for a hand tool employs a high-voltage transmission of power from a battery pack over a cord to a DC to DC converter, which steps the transmission voltage down to rated tool voltage. The system uses a switching transistor to transmit power according to a duty cycle which varies automatically according to tool current draw and voltage. The DC to DC converter employs synchronous rectification with an inductor-capacitor network to transform a duty cycle square wave into DC power. The startup voltage sense feature permits powering up the converter circuitry only when needed. The converter will shut down if no current has been drawn by the tool for a predetermined period of time or if the converter unit is in danger of overheating, as determined by a stored algorithm. The portable power system has safeguards to prevent fouling or shorting in wet environments, is adaptable to left or right handed users, and is physically configurable into a variety of carrying modes.