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. 21, 1995
Filed:
Nov. 16, 1992
Egon Konigbauer, Olching, DE;
Wolfgang Millauer, Munich, DE;
Hilti Aktiengesellschaft, Liechtenstein, DE;
Abstract
A circuit arrangement is disclosed for a non-contacting switch-over of operational parameters in an electrically driven tool, for instance, a hammer drill, which are determined by a voltage divider ratio with reference to a stabilized supply source. The voltage divider ratio is obtained by selective parallel switching of an additional ohmic resistor by means of a Hall switch, whose current supply is supplied by a Zener diode which lies in series with the stabilized supply source. The circuit of the Hall switch puts the low point of the additional resistor, connected through a diode, to the low point of the voltage divider, in parallel with the partial resistor of the voltage divider, through a drop resistance. The switching arrangement or circuit arrangement has the advantage that the current supply of an RPM control unit is only slightly additionally loaded or increased.