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. 02, 1991
Filed:
Dec. 01, 1989
Albrecht Schnizler, Nurtingen, DE;
Rolf Benzing, Neuffen, DE;
Metabowerke GmbH & Co., Nurtingen, DE;
Abstract
A cordless electrical tool has a housing forming a pair of battery mounts, an electrical motor in the housing, respective batteries removably carried in the mounts, and circuitry connecting the batteries in series with each other and across the motor. A cutoff switch is connected in series between the batteries and the motor and can open to electrically disconnect the motor from the batteries. Respective control circuits detect the charge levels of the batteries and open the cutoff switch when the respective charge level drops below a predetermined threshold. Respective light-emitting diodes are provided to indicate which of the batteries is below its permissible charge.