Belt retractor comprising a locking pawl actuated by an electromagnet

• US 20030034416A1
• Filed: 08/07/2002
• Published: 02/20/2003
• Est. Priority Date: 08/20/2001
• Status: Active Grant

• Current Assignee: TRW Occupant Restraint Systems GmbH & Co. KG
• Original Assignee: TRW Occupant Restraint Systems GmbH & Co. KG
• Inventors: Holbein, Wolfgang
• Granted Patent: US 6,755,369 B2
• Time in Patent Office: Days
• US Class Current: 242/384
• CPC Class Codes: B60R 22/343 with electrically actuated locking means B60R22/3405 takes precedence

Abstract

A belt retractor has a locking pawl actuated by an electromagnet The electromagnet is operated with a holding power that is reduced in comparison to its actuation power. The holding power may be provided by a series device in the current supply of the electromagnet. The series device may generate a holding voltage that is limited to a predefined value, or it may provide a pulse duration modulated d.c. supply voltage.

Claims

1. A belt retractor comprising a locking pawl actuated by an electromagnet, wherein the electromagnet is operated with an electric holding power that is reduced in comparison to electric power required for actuation of the locking pawl.

2. The belt retractor according to claim 1, wherein the reduced holding power is provided by a series device connected in the current supply to the electromagnet.

3. The belt retractor according to claim 2, wherein the series device for reducing the holding power generates a holding voltage that is limited to a predefined value

4. The belt retractor according to claim 2, wherein the series device for reducing the holding power applies to the electromagnet a pulse duration modulated d.c. voltage.

5. The belt retractor according to claim 2, wherein the electromagnet has a separate holding winding.

6. The belt retractor according to claim 1, wherein switching from actuating power to holding power depends on a criterion such as

period of actuation time,

heating up of the electromagnet

position of the locking pawl,

electric parameters.