# US 8,740,125 B2 · Seatbelt retractor

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- Number: US 8,740,125 B2
- Document ID: US8740125B2
- Status: Granted
- Kind: B2
- Application number: 13/264,870
- Filed: 2010-03-31
- Published: 2012-02-23
- Granted: 2014-06-03
- Earliest claimed: 2009-04-17
- Assignees: Autoliv Development AB
- Applicants: Kiyoshi Ogawa; Katsuyasu Ono; Yuichi Hamano
- Inventors: Kiyoshi Ogawa; Katsuyasu Ono; Yuichi Hamano
- Web page: https://patentgrep.com/patent/US8740125B2

## CPC

- B60R 22/4628: {characterised by fluid actuators, e.g. pyrotechnic gas generators (actuating a cable B60R22/4619)}
- B60R 2022/287: {of torsion rods or tubes}
- B60R 2022/4642: {the gas directly propelling a flexible driving means, e.g. a plurality of successive masses, in a tubular chamber}
- B60R: VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR

## Abstract

A seatbelt retractor having a switching device with a gas generator and a switch housing having a gas generator housing portion for accommodating the gas generator and a gas flow path that communicates with the gas generator housing portion so that gas generated by the gas generator passes through the gas flow path. Further, the gas generator housing portion and the gas flow path are formed in the switch housing in a curved shape, and a die-cut hole extending in a direction of the gas flow path on an opposite side of the gas flow path to the gas generator housing portion is blocked from the gas flow path by the gas generator.

## Claims

### Claim 1

A seatbelt retractor comprising:
a refractor frame;
a spindle supported by the retractor frame and being freely rotatable;
a lock member that is supported by the retractor frame and configured to become fixed to the retractor frame when acceleration exceeds a predetermined value;
a torsion bar that is disposed on a force transmission path between the spindle and the lock member and includes a plurality of shaft parts having different twisting torques; and
a switching device for switching the plurality of shaft parts of the torsion bar forming the force transmission path,
wherein the switching device includes a switch piston, a gas generator, and a switch housing having a gas generator housing portion defining a bore in which the gas generator is received, the switch housing having a gas flow passageway that communicates with the bore so that gas generated by the gas generator passes through the gas flow passageway to the piston,
the gas flow passageway being located between the bore and the piston and being formed in the switch housing diagonally with respect to central axis through the bore, and
a hole defined in the switch housing on an sidewall of the bore that is opposite from the gas flow passageway, the gas generator being positioned in the bore between the hole and the gas flow passageway and blocking the hole so as to prevent gas generated by the gas generator from flowing out of the hole.

### Claim 2 (depends on 1)

The seatbelt retractor according to claim 1, wherein the bore extends horizontally when the retractor is attached to a vehicle.

### Claim 3 (depends on 2)

The seatbelt retractor according to claim 2, wherein the switch housing is attached to an inner side of a side plate of the retractor frame.

### Claim 4 (depends on 3)

The seatbelt retractor according to claim 3, wherein the bore is disposed in an upper portion of the switch housing.

### Claim 5 (depends on 4)

The seatbelt retractor according to claim 4, wherein the hole is coaxial with the gas flow passageway.

### Claim 6 (depends on 2)

The seatbelt retractor according to claim 2, wherein the hole is coaxial with the gas flow passageway.

### Claim 7 (depends on 3)

The seatbelt retractor according to claim 3, wherein the hole is coaxial with the gas flow passageway.

### Claim 8 (depends on 1)

The seatbelt retractor according to claim 1, wherein the hole is coaxial with the gas flow passageway.

### Claim 9 (depends on 1)

The seatbelt retractor according to claim 1, wherein the switch housing is attached to an inner side of a side plate of the retractor frame.

### Claim 10 (depends on 9)

The seatbelt retractor according to claim 9, wherein when the refractor is attached to a vehicle and the bore is disposed in an upper portion of the switch housing.

### Claim 11 (depends on 1)

The seatbelt retractor according to claim 1, wherein the piston is moveable along an axis defined by the torsion bar.

### Claim 12 (depends on 1)

The seatbelt retractor according to claim 1, wherein the piston is coaxial with the torsion bar.

### Claim 13 (depends on 12)

The seatbelt retractor according to claim 12, wherein the hole and the passageway have a cross-sectional shape that is the same.

### Claim 14 (depends on 1)

The seatbelt retractor according to claim 1, wherein the hole and the passageway have a cross-sectional shape that is the same.