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. 04, 2008
Filed:
Mar. 16, 2006
Applicants:
Kwok Kuen Tse, Hong Kong, CN;
En Hui Wang, Shenzhen, CN;
Inventors:
Kwok Kuen Tse, Hong Kong, CN;
En Hui Wang, Shenzhen, CN;
Assignee:
Johnson Electric S.A., La Chaux-de-Fonds, CH;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02P 1/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
A drive circuit for a hair clipper comprises an electric motor and a control circuit for operating the motor at a constant speed regardless of load conditions. The control circuit has detector means for sensing the supply voltage to the clipper and the clipper current, processor means for generating an error signal indicative of a change in supply voltage needed to maintain a constant motor speed and driver means responsive to the error signal for adjusting the supply voltage to the motor to maintain the speed constant.