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:
Jun. 08, 1999
Filed:
Apr. 23, 1997
W Darrell Buchanan, Monrovia, CA (US);
Paul MacCready, Monrovia, CA (US);
Aerovironment Inc., Monrovia, CA (US);
Abstract
This disclosure describes an improved electrical power apparatus for assisting a rider in powering a wheeled vehicle such as a bicycle. The apparatus controllably connects a rechargeable battery to a dc motor engageable with a wheel of the vehicle in a predetermined fashion, such that the wheel is driven with a torque that varies with the vehicle's speed according to a predetermined non-uniform profile. This control advantageously can be achieved by modulating on and off a switch at a duty cycle between 0% and 100%, which is selected to provide a motor torque that decreases monotonically with the vehicle's speed, from a maximum value at zero speed to a predetermined intermediate value at a predetermined intermediate speed, and that remains at that predetermined intermediate value for speeds between the intermediate speed and a predetermined maximum speed. The apparatus further includes a charger for charging the battery using a flyback-type dc-to-dc converter.