GB2345891A - Seat belt retractor with force limiting means - Google Patents
Seat belt retractor with force limiting means Download PDFInfo
- Publication number
- GB2345891A GB2345891A GB0011285A GB0011285A GB2345891A GB 2345891 A GB2345891 A GB 2345891A GB 0011285 A GB0011285 A GB 0011285A GB 0011285 A GB0011285 A GB 0011285A GB 2345891 A GB2345891 A GB 2345891A
- Authority
- GB
- United Kingdom
- Prior art keywords
- spool
- limiting means
- seat belt
- force limiting
- spring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R22/00—Safety belts or body harnesses in vehicles
- B60R22/34—Belt retractors, e.g. reels
- B60R22/341—Belt retractors, e.g. reels comprising energy-absorbing means
- B60R22/3413—Belt retractors, e.g. reels comprising energy-absorbing means operating between belt reel and retractor frame
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R22/00—Safety belts or body harnesses in vehicles
- B60R22/34—Belt retractors, e.g. reels
- B60R22/341—Belt retractors, e.g. reels comprising energy-absorbing means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R22/00—Safety belts or body harnesses in vehicles
- B60R22/34—Belt retractors, e.g. reels
- B60R22/46—Reels with means to tension the belt in an emergency by forced winding up
- B60R22/4676—Reels with means to tension the belt in an emergency by forced winding up comprising energy-absorbing means operating between belt reel and retractor frame
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R22/00—Safety belts or body harnesses in vehicles
- B60R22/28—Safety belts or body harnesses in vehicles incorporating energy-absorbing devices
- B60R2022/282—Safety belts or body harnesses in vehicles incorporating energy-absorbing devices using fluids or vico-elastic materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R22/00—Safety belts or body harnesses in vehicles
- B60R22/28—Safety belts or body harnesses in vehicles incorporating energy-absorbing devices
- B60R2022/285—Safety belts or body harnesses in vehicles incorporating energy-absorbing devices using friction surfaces
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R22/00—Safety belts or body harnesses in vehicles
- B60R22/28—Safety belts or body harnesses in vehicles incorporating energy-absorbing devices
- B60R2022/286—Safety belts or body harnesses in vehicles incorporating energy-absorbing devices using deformation of material
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Automotive Seat Belt Assembly (AREA)
Abstract
A seat belt retractor comprises: a spool 1 mounted on a shaft 10 for rotation; a length of seat belt webbing wound on the spool for retraction or pay-out; means for locking the spool shaft against rotation when a crash condition is sensed; and force limiting means for allowing further pay-out of the webbing after the spool has locked. The force limiting means comprises an energy absorbing arrangement connecting the spool to the spool shaft by means of a resilient biasing member, the connection being rigid below a pre-determined force, and above the pre-determined force there being relative rotation of the spool with respect to the spool shaft. The force limiting means may comprise a coiled tension spring 17 wound around the spool shaft, or it may comprise a clock spring or a spring operating in a similar manner to a normal retractor spring. The force limiting means is intended to reduce excessive forces applied to the occupants body during a vehicle impact.
Description
RETRACTOR SPOOL
DESCRIPTION
The present application is divided from GB 97 01 443. 5 and is related to copending divisional application GB 00 11 281. 3
The present invention relates to a retractor spool for a vehicle safety restraint.
A retractor spool generally consists of a cylindrical bobbin with a circular cross-section. Seat belt webbing is attached to and wound around the spool and the spool is mounted on a spool shaft to be rotatable in the retractor to wind in webbing under action of a retractor spring and to pay out webbing under the influence of relatively gentle forwardly directed inertia of a vehicle occupant, for example to allow for normal movement associated with vehicle occupancy such as reaching forwards to activate in-car controls (for a radio or a window) or to reach a glove compartment or door pocket. In the event of a crash situation, the more extreme momentum of the occupant activates a crash sensor which locks the spool against rotation and thus prevents forward motion of the occupant and injury due to occupant collision with the interior fixtures of the vehicle such as the steering wheel, dashboard or windscreen.
However, this sudden locking of the seat belt spool under crash conditions can itself sometimes cause injury to the occupant due to sudden impact of the torso with the belt webbing. This is particularly true in high velocity crashes.
In recent years this problem has been recognised and some solutions proposed.
One solution has been to rely on natural elongation of the webbing under high loads, and on the spool film effect (natural tightening of the webbing wound on the spool under high loads), to produce a load limiting effect.
Another known proposal has been described in EP 0 297 537 A, wherein force limiting is effected by interposing a plastically deformable member between the spool and the innermost winding of the belt webbing or by interposing an elastic member such as a spring rubber member or resin member between an end flange of the spool and the latch plate. This allows a pay-out of webbing in proportion to the inertia of the vehicle occupant at the moment of a crash condition being sensed. This pay-out lessens the otherwise severe restraining forces on the occupant at high vehicle speeds especially during the initial moments of the crash.
It thus reduces the injurious effects of the seat belt in a crash.
The present invention proposed improved load limiting arrangements for retractors.
According to one aspect of the present invention there is provided A seat belt retractor comprising a spool mounted on a spool shaft for rotation in the retractor, a length of seat belt webbing wound on the spool for retraction or pay out depending on the rotation direction of the spool; means for Locking the spool shaft against rotation when a crash condition is sensed; force limiting means for allowing further pay-out of the seat belt webbing after the spool shaft has locked, under the influence of an occupant's forward momentum in the crash condition, wherein the force limiting means comprises an energy absorbing arrangement connecting the spool to the spool shaft, the connection being rigid below a predetermined force, and above the predetermined force there being relative rotation of the spool with respect to the spool shaft to allow pay out of belt webbing; wherein the force limiting means comprises resilient biasing means acting between the spool and the spool shaft.
The force limiting means comprises an energy absorbing member connecting the spool to the spool shaft, the connection being rigid below a predetermined force, and above the predetermined force there being relative rotation of the spool with respect to the spool shaft to allow pay out of belt webbing.
The invention is particularly applicable to the load limiting retractor known as the constant force retractor and described in co-pending International application PCT/US95/15002, publication WO 96/16843.
The force limiting means comprises resilient biasing means acting between the spool and its axis of rotation, for example a coiled tension spring wound around a spool shaft coaxial with the spool, or a clock spring or springs operating in a similar manner to a normal retractor spring.
In such an arrangement there will be an initial preset torque in the spring which determines the minimum load at which limiting starts to occur. As the load increases beyond this minimum, the spring is wound up tight and the diameter of its centre bore decreases. A maximum force limitation occurs when the spring is wound tightly about the spool shaft.
Alternatively this arrangement could be used with a spring mechanism the centre bore size of which increases with increasing load up to a maximum determined by the size of the internal bore of the spool.
This aspect of the invention is particularly advantageous because the force limiting means is re-usable and is automatically reset after crash conditions have abated. After impact the restrained occupant rebonds off the belt into his seat. The taut spring then uncoils, rewinding slack in the belt webbing and satisfactorily restraining the occupant in the event of a second impact.
For a better understanding and to show how the same may be carried into effect, reference will now be made to the accompanying drawings in which:
The sole figure is a cross-sectional view of a
retractor according to the invention;
Like parts are denoted by like reference numerals throughout.
In the single figure a torsion spring 17 is coiled around the spool shaft 10 within the hollow of spool 1. It is fixed at its ends 18 to the spool and at its middle to shaft 10 by pin or bolt 19.
In a crash impact the forward momentum of the occupant being restrained acts on the spool 1 to try to pay out more belt webbing. Since the shaft 10 is locked by a locking mechanism, activated by a crash sensor, then the relative rotation of the spool to the shaft tightens the spring 17 as more webbing is paid out, until the spring is coiled tightly around the shaft at which point pay-out ceases since the spool 1 is locked to the locked shaft 10.
When webbing tension is released as the crash conditions abate, the spring acts to rotate the spool in a rewinding direction thus drawing in the extra payed-out webbing together with any slack (which may have been caused by webbing stretch or by cinching of webbing on the spool).
Thus the occupant is well protected against a second impact.
If the spring 17 is wound the opposite way then, as webbing is paid out in a load limiting operation, the spring will expand until it fills the spool 1, which defines therefore the maximum force at which load limiting operates.
The spring will draw in webbing as it subsequently recoils itself.
Claims (5)
1. A seat belt retractor comprising a spool mounted on a spool shaft for rotation in the retractor,
a length of seat belt webbing wound on the spool for retraction or pay-out depending on the rotation direction of the spool;
means for locking the spool shaft against rotation when a crash condition is sensed;
force limiting means for allowing further pay-out of the seat belt webbing after the spool shaft has locked, under the influence of an occupant's forward momentum in the crash condition,
wherein the force limiting means comprises an energy absorbing arrangement connecting the spool to the spool shaft, the connection being rigid below a predetermined force, and above the predetermined force there being relative rotation of the spool. with respect to the spool shaft to allow pay out of belt webbing; wherein the force limiting means comprises resilient biasing means acting between the spool and the spool shaft.
2. A seat belt retractor according to claim 1 wherein the force limiting means comprises a coiled tension spring wound around a spool shaft coaxial with the spool.
3. A seat belt retractor according to claim 1 or 2 wherein the force limiting means comprises a clock spring.
4. A seat belt retractor according to claim 1 or 2 wherein the force limiting means comprises a spring operating in a similar manner to a normal retractor spring.
5. A retractor substantially as hereinbefore described with reference to the accompanying drawings.
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GBGB9601352.9A GB9601352D0 (en) | 1996-01-24 | 1996-01-24 | Retractor spool |
GBGB9617137.6A GB9617137D0 (en) | 1996-08-15 | 1996-08-15 | Retractor |
GBGB9624139.3A GB9624139D0 (en) | 1996-11-20 | 1996-11-20 | Retractor spool |
GB9701443A GB2312148B (en) | 1996-01-24 | 1997-01-24 | Retractor spool |
Publications (3)
Publication Number | Publication Date |
---|---|
GB0011285D0 GB0011285D0 (en) | 2000-06-28 |
GB2345891A true GB2345891A (en) | 2000-07-26 |
GB2345891B GB2345891B (en) | 2000-10-04 |
Family
ID=27451388
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB0011281A Expired - Fee Related GB2346849B (en) | 1996-01-24 | 1997-01-24 | Retractor spool |
GB0011285A Expired - Fee Related GB2345891B (en) | 1996-01-24 | 1997-01-24 | Retractor spool |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB0011281A Expired - Fee Related GB2346849B (en) | 1996-01-24 | 1997-01-24 | Retractor spool |
Country Status (1)
Country | Link |
---|---|
GB (2) | GB2346849B (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2003089281A1 (en) * | 2002-04-16 | 2003-10-30 | Key Safety Systems, Inc. | Seat belt retractor |
EP1982875A3 (en) * | 2007-04-17 | 2009-06-17 | HS Products Engineering GmbH | Belt roller for an automobile seatbelt |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1440232A (en) * | 1972-06-24 | 1976-06-23 | Kangol Teka Sicherheitsgurt Gm | Safety belt winding drums |
US4323205A (en) * | 1979-07-19 | 1982-04-06 | Nippon Soken, Inc. | Safety seat-belt retractor |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1324667A (en) * | 1972-04-04 | 1973-07-25 | Ford Motor Co | Motor vehicle seat belt reel |
DE2344878A1 (en) * | 1973-09-06 | 1975-03-20 | Happich Gmbh Gebr | UNWINDING DEVICE WITH ENERGY DEVICE FOR SAFETY BELTS |
IT1014283B (en) * | 1974-06-04 | 1977-04-20 | Fiat Spa | ENERGY SINK FOR SEAT BELTS OF VEHICLES |
US6106013A (en) * | 1995-06-30 | 2000-08-22 | Doty; Gerald Arthur | Controlled force shoulder belt system |
-
1997
- 1997-01-24 GB GB0011281A patent/GB2346849B/en not_active Expired - Fee Related
- 1997-01-24 GB GB0011285A patent/GB2345891B/en not_active Expired - Fee Related
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1440232A (en) * | 1972-06-24 | 1976-06-23 | Kangol Teka Sicherheitsgurt Gm | Safety belt winding drums |
US4323205A (en) * | 1979-07-19 | 1982-04-06 | Nippon Soken, Inc. | Safety seat-belt retractor |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2003089281A1 (en) * | 2002-04-16 | 2003-10-30 | Key Safety Systems, Inc. | Seat belt retractor |
US6712305B2 (en) | 2002-04-16 | 2004-03-30 | Breed Automotive Technology, Inc. | Seat belt retractor |
CN1305716C (en) * | 2002-04-16 | 2007-03-21 | 关键安全体系股份有限公司 | Seat belt retractor |
EP1982875A3 (en) * | 2007-04-17 | 2009-06-17 | HS Products Engineering GmbH | Belt roller for an automobile seatbelt |
Also Published As
Publication number | Publication date |
---|---|
GB0011285D0 (en) | 2000-06-28 |
GB2346849A (en) | 2000-08-23 |
GB0011281D0 (en) | 2000-06-28 |
GB2345891B (en) | 2000-10-04 |
GB2346849B (en) | 2000-11-01 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20050124 |