Detection system and switch device

• US 6,429,782 B2
• Filed: 04/05/1999
• Issued: 08/06/2002
• Est. Priority Date: 04/03/1998
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Pavatich, Gianfranco, Gangemi, Daniel Phillip
• Primary Examiner(s): Wu, Daniel J.
• Assistant Examiner(s): Huang, Sihong
• Application Number:
  US09/286,076
• Time in Patent Office: 1,219 Days
• Field of Search: 340/686.6, 340/825.31, 340/562, 340/407.1, 340/658, 361/181, 307/10.3, 307/10.2
• US Class Current: 340/686.6
• CPC Class Codes: E05B 81/77 comprising sensors detecting the presence of the hand of a user
• CPC Class Codes: E05B 81/78 as part of a hands-free locking or unlocking operation
• CPC Class Codes: H03K 17/955 using a capacitive detector
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2217/958 involving transponders
• CPC Class Codes: H03K 2217/960765 Details of shielding arrangements

Abstract

A detection system includes a switch device having a conductor forming part of a capacitor with variable capacitance dependent upon proximity of a person, and a detector for sensing variation in the capacitance and for generating an output signal indicating the proximity of the person relative to the conductor. The switch device further includes a retaining body adapted to mount the conductor to a door handle, the retaining body also having a mechanical switch arranged for actuation by a person gripping the handle to additionally or alternatively indicate the proximity of the person.

Claims

1. A detection system comprising:

a switch device including a conductor forming part of a capacitor having a variable capacitance dependent upon a proximity of a person; and

a detector for sensing a variation in the capacitance and for generating an output signal indicating the proximity of the person relative to the conductor,

wherein the switch device further includes a retaining body adapted to mount the conductor to a door handle, the retaining body having a switch arranged for an actuation by a person gripping the door handle to indicate the proximity of the person,

wherein the detector includes an oscillator coupled to the conductor and includes a phase comparator, the variation in the capacitance resulting in an associated change in a frequency of oscillation in the oscillator, to produce a phase modulated signal therein which is input to the phase comparator so as to generate a signal representative of the change in frequency.

2. The detection system according to claim 1, wherein the phase comparator forms a part of a phase-locked loop circuit and the detector further includes a comparator, a feedback/error signal of the circuit being input to the comparator for a comparison with a threshold level so as to generate the output signal indicating the proximity of the person.

3. A security system comprising:

a switch device including a conductor forming part of a capacitor having a variable capacitance dependent upon a proximity of a person;

a detector for sensing a variation in the capacitance and for generating an output signal indicating the proximity of the person relative to the conductor,

wherein the switch device further includes a retaining body adapted to mount the conductor to a door handle, the retaining body having a switch arranged for an actuation by a person gripping the door handle to indicate the proximity of the person;

a lock; and

a control unit actuating an interrogation procedure, upon detecting the proximity of the person, for checking a security associated with the person and releasing the lock if predetermined security requirements are met.

4. The security system according to claim 3, wherein the security system is a vehicle locking or disabling system which is actuated by the control unit for interrogating a corresponding transponder carried by the person.