Seatbelt retractor

• US 20020096591A1
• Filed: 12/26/2001
• Published: 07/25/2002
• Est. Priority Date: 01/22/2001
• Status: Active Grant

• Current Assignee: Joyson Safety Systems Japan K.K.
• Original Assignee: Takata Corporation (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Tanji, Hiromasa
• Granted Patent: US 6,702,219 B2
• Time in Patent Office: Days
• US Class Current: 242/390.8
• CPC Class Codes: B60R 2022/287 of torsion rods or tubes
• CPC Class Codes: B60R 2022/4666 characterised by electric actuators
• CPC Class Codes: B60R 2022/468 characterised by clutching means between actuator and belt reel
• CPC Class Codes: B60R 22/343 with electrically actuated locking means B60R22/3405 takes precedence
• CPC Class Codes: B60R 22/44 with means for reducing belt tension during use under normal conditions not included in the retractor B60R22/19; B60R22/3405 takes precedence
• CPC Class Codes: B60R 22/46 Reels with means to tension the belt in an emergency by forced winding upelectrical circuits for triggering safety arrangements B60R21/01 ; tensioners using reels only guiding the belt during normal use, e.g. splitted reels B60R22/195
• CPC Class Codes: B60R 22/4676 comprising energy-absorbing means operating between belt reel and retractor frame

Abstract

In a seatbelt retractor having a motor, a belt winding spool, and a switching mechanism that turns on and off a power transmission route between the motor and the spool, the switching mechanism includes a device that connects the power transmission route between the motor and the spool only when the motor rotates in the retracting direction. A ratchet mechanism allows the spool to rotate only in the retraction direction during the emergency operation, while allowing the spool in any directions in the normal operation. The resultant locking mechanism can be rapidly operated upon occurrence of an emergency, while the seatbelt retractor will not cause uncomfortable feeling or unpleasantness due to unnecessary locking when an occupant tries to withdraw the seatbelt.

Claims

1. A seatbelt retractor, comprising:

a motor,

a belt winding spool connected to the motor, and

a power transmission route interposed between the motor and the spool,

a switching mechanism connected to the power transmission route for turning on and off the same, said switching mechanism connecting the power transmission route from the motor to the spool only when the motor rotates in a retracting direction, and

a ratchet mechanism connected to the spool, said ratchet mechanism having operation means for allowing the spool to rotate only in the retraction direction when the operation means is actuated, and allowing the spool to rotate in retracting and withdrawing directions when the operation means is not actuated.

2. A seatbelt retractor according to claim 1, wherein said switching mechanism is connected to and driven by the motor for turning on the transmission route.

3. A seatbelt retractor according to claim 1, wherein said power transmission route includes a power transmission gear mechanism, and switching mechanism includes a rotatable control lever for controlling operation of the switching mechanism.

4. A seatbelt retractor according to claim 3, wherein said power transmission route includes a reduction mechanism, said reduction mechanism including:

a sun gear connected to one of the motor and the spool,

a ring-shaped internal gear having ratchet teeth at an external periphery and internal teeth on an internal periphery thereof,

planetary gears connected to the other of the motor and the spool and engaging the sun gear and the internal gear,

a carrier for supporting the planetary gears and transmitting revolution of the planetary gears to the spool, and

a reduction gear connected to said one of the motor and spool, and rotated integrally with the sun gear to receive rotation of the motor from the power transmission gear mechanism.

5. A seatbelt retractor according to claim 4, wherein said switching mechanism includes a retaining lever switchable between positions disengaged from and engaged with the ratchet teeth of the ring-shaped internal gear.

6. A seatbelt retractor according to claim 1, wherein said ratchet mechanism comprising:

a ratchet gear having saw-blade teeth at an external periphery thereof,

a pawl situated adjacent to the ratchet gear to be engagable with the saw-blade teeth of the ratchet gear,

an elastic body connected to the pawl, and

driving means connected to the elastic body for driving the pawl so as to engage with the saw-blade teeth of the ratchet gear.

7. A seatbelt retractor according to claim 1, wherein said ratchet mechanism comprises:

a ratchet gear having saw-blade teeth at an external periphery thereof,

a pawl situated adjacent to the ratchet gear to be engagable with the saw-blade teeth,

a ratchet lever connected to the pawl having a rotational pivot for pivoting the pawl, and

reciprocation driving mean connected to the pawl for controlling the pawl.

8. A seatbelt retractor according to claim 7, further comprising a a housing having a hole, said pawl having a pin fitted into the hole.

9. A seatbelt retractor according to claim 8, wherein said ratchet mechanism further includes an elastic body attached to the pawl for urging the pawl to the ratchet gear.