Keyless system for actuating a motor-vehicle door latch

US7126453B2 · kind B2 · utility

Assignee

• Kiekert AG · DE

Inventors

• Helmut Sandau · Velbert, DE
• Bernd Gerdes · Essen, DE

Key dates

• Filing date: Feb 19, 2002
• Grant date: Oct 24, 2006
• Expiry date: Sep 28, 2022

Classification

• Technology area (CPC G): Physics
• CPC primary: G07C2209/65
• WIPO field: Civil engineering
• WIPO sector: Other fields

Abstract

A keyless actuating system has a switchable electrical device, a coded transponder adapted to be carried by a user, and a vehicle-mounted interrogating unit adapted when enabled to remotely coact with the transponder for switching the device when the transponder holds a predetermined code. A first capacitor element is carried on the vehicle, and a second capacitor element is carried on the user. A control circuit determines the capacitance between the first and second elements when the user is near the vehicle for enabling the interrogating unit only when the capacitance between the first and second elements passes a predetermined threshold. Normally the second capacitor element is actually the user.