Abstract: A pretensioner for a three point seat belt has a cylinder adapted to be attached to a structural member of the vehicle and a piston disposed within the cylinder. The piston can move translationally relative to the cylinder in a pretensioning direction. A flexible member is arranged in a curved profile with a seat belt webbing being attached to the flexible member. The flexible member has a first end that can be pulled by the piston and a second end releasably connected to an exterior of the cylinder such that when the piston moves translationally relative to the cylinder the second end of the flexible member moves translationally relative to the cylinder along the exterior of the cylinder.

Abstract: A pretensioner for a three point seat belt has a cylinder adapted to be attached to a structural member of the vehicle and a piston disposed within the cylinder. The piston can move translationally relative to the cylinder in a pretensioning direction. A flexible member is arranged in a curved profile with a seat belt webbing being attached to the flexible member. The flexible member has a first end that can be pulled by the piston and a second end releasably connected to an exterior of the cylinder such that when the piston moves translationally relative to the cylinder the second end of the flexible member moves translationally relative to the cylinder along the exterior of the cylinder.

Abstract: A seat belt retractor for a vehicle safety restraint has a spool rotatably mounted in a frame. A ratchet wheel is rotatably mounted to rotate with the spool. A control member is mounted in the frame. A locking pawl is pivotally mounted in the frame to pivot into engagement with the ratchet wheel. A sensor is responsive to the spool. Upon activation of the sensor, a cam surface and a cam follower couple the locking pawl to the control member. The cam surface has a discontinuity arranged so that the cam follower loses contact with the cam at high speeds but stays in contact with the cam surface at low speeds. Preferably, the discontinuity is a raised portion providing a first ramp in one direction in one portion on one side of the discontinuity of the cam surface and a second ramp in a different direction in a second portion of the cam surface on the other side of the discontinuity.

Abstract: A seat belt retractor has a web sensor with an inertia member, a locking pawl and a lock cup. The inertia member is eccentrically pivotally mounted to the lock cup. The locking pawl is integrally formed with the inertia member. The lock cup has a set of radially inwardly pointing teeth for engaging with the locking pawl. The shape and profile of the locking pawl complements the shape of the teeth. The web sensor aids in resisting jamming of the seat belt retractor.

Abstract: A seat belt retractor has a web sensor with an inertia member, a locking pawl and a lock cup. The inertia member is eccentrically pivotally mounted to the lock cup. The locking pawl is integrally formed with the inertia member. The lock cup has a set of radially inwardly pointing teeth for engaging with the locking pawl. The shape and profile of the locking pawl complements the shape of the teeth. The web sensor aids in resisting jamming of the seat belt retractor.

Abstract: A seat belt retractor for a vehicle safety restraint has a spool rotatably mounted in a frame. A ratchet wheel is rotatably mounted to rotate with the spool. A control member is mounted in the frame. A locking pawl is pivotally mounted in the frame to pivot into engagement with the ratchet wheel. A sensor is responsive to the spool. Upon activation of the sensor, a cam surface and a cam follower couple the locking pawl to the control member. The cam surface has a discontinuity arranged so that the cam follower loses contact with the cam at high speeds but stays in contact with the cam surface at low speeds. Preferably, the discontinuity is a raised portion providing a first ramp in one direction in one portion on one side of the discontinuity of the cam surface and a second ramp in a different direction in a second portion of the cam surface on the other side of the discontinuity.

Abstract: A buckle pretensioner for a vehicle safety restraint comprising a buckle head (1) for receiving a buckle tongue to secure safety restraint webbing about a vehicle occupant in a three-point belt system, a cable (2) connected to the buckle head (1); and means (7) for rapidly withdrawing the cable in a belt tightening direction, the withdrawing means (7) comprising a force reservoir (8), and driving means (6), and being of a compact construction through the use of step-up gearing (3, 4) to magnify linear movement produced by the force reservoir (8) which may be a pyrotechnic gas generator or a spring. The driving means (8) may be a piston-cylinder (6, 8) or a rack and pinion. The gearing may comprise a pulley arrangement (3, 4). Alternatively a roots motor or a gear pump could be used.

Abstract: A buckle pretensioner for a vehicle safety restraint comprising a buckle head (1) for receiving a buckle tongue to secure safety restraint webbing about a vehicle occupant in a three-point belt system; a cable (2) connected to the buckle head (1); and device (7) for rapidly withdrawing the cable in a belt tightening direction, the withdrawing device (7) comprising a force reservoir (8), and driving mechanism (6), and being of a compact construction through the use of set-up gearing (3,4) to magnify linear movement produced by the force reservoir (8) which may be a pyrotechnic gas generator or a spring. The driving mechanism (8) may be a piston-cylinder (6,8) or a rack and pinion. The gearing may comprise a pulley arrangement (3,4). Alternatively a roots motor or a gear pump could be used.

Abstract: A seat belt retractor has a frame with sidewalls and a rotatable spool extending between said sidewalls. The rotatable spool has seat belt webbing wound thereon. A locking pawl engages ratchet teeth on the outer periphery of the spool for arresting rotation of the spool. A secondary locking mechanism locks the spool against rotation.

Abstract: Two parts of a seat belt retractor spool sub-assembly are fixed together in an arrangement with plastically deformable formations on a first ratchet wheel and one end of a spool and corresponding deforming formations on a second ratchet wheel and said one end of the spool. A spool for a seat belt retractor is assembled with a ratchet wheel by: mounting a retractor frame on an assembly jig which has a spring loaded stop; mounting a spool in the frame by aligning the spool axis with the spring loaded stop; and pushing a ratchet wheel onto the end of the spool opposite to that contacting the stop until the ratchet wheel abuts the frame.

Abstract: A spool for a seat belt retractor has a cylindrical member with a cylindrical central portion and two end plates at opposite axial ends of the cylindrical portion. There is a channel formed in the cylindrical central portion with an outer and an inner wall and defining a path for guiding seat belt webbing. The path circumscribes the spool axis substantially over the length of the central portion of the spool in a generally smooth curve. The path has a spool entry and a spool exit portion and an acute angle subtended at the spool axis by the entry portion of the path and the exit portion of the path is approximately 90°. The spool may be hollow with a torsion bar forming the inner wall of the channel.

Abstract: A lockbar for a seatbelt retractor has an elongate joining member and two end pieces joined to the joining member at opposite ends therefore. The end pieces are made of a higher strength material than the joining member. The joining member may be made by extrusion and may be tubular or may be formed as a hollow member. The end pieces may be produced as forgings, die casting or plastic injection moldings or by other suitable methods. They can be produced from different materials and to different designs to suit the specification of the seatbelt retractor. Hence a single basic seatbelt retractor design can be employed for a variety of strength requirements by selecting appropriate end pieces and an appropriate joining member.

Abstract: A seat belt retractor has a spool that is rotatable about an axis for receiving seat belt webbing. A locking means prevents rotation of the spool during a crash to prevent webbing payout. A load limiting means has a torsion bar extending through the spool and connected in a force path between the locking means and the webbing. One end of the torsion bar is attached to the spool, and the opposite end of the torsion bar is attached to a toothed wheel, wherein said opposite end of the torsion bar is connected to the toothed wheel in an axially adjustable manner.

Abstract: A seat belt retractor spool has a spool body with opposed end flanges. A ratchet wheel is arranged on one end flange. A torsion bar is located in a bore in the spool body and is coupled to the ratchet wheel by means of a toothed portion at one end thereof. The other end of the torsion bar has a plurality of radial projections which cooperate with axial protrusions on the end flange to couple the bar 10 to the spool.

Abstract: A seat belt retractor has a webbing spool fixed to a ratchet wheel having a plurality of teeth spaced about its circumference. A locking pawl has a plurality of teeth with a pitch less than the pitch of the teeth on the ratchet wheel. The pawl is arranged to pivot into engagement with the ratchet wheel, on activation of a crash sensor. Preferably there are two locking pawls and two toothed ratchet wheels. The two locking pawls may each have the same number of teeth or alternatively one may have an extra tooth which serves as a sensor tooth, engaging first with the spool ratchet wheel and phasing engagement of the other teeth as the load increases.

Abstract: A seat belt retractor has a spool on which seat belt webbing is wound, arranged for rotation about its longitudinal axis, for payout and winding in of seat belt webbing. A torsion bar is coaxial with the spool and has one end fixed to the spool. A ratchet is fixed to the other end of the torsion bar and a toothed wheel is fixed to the spool to rotate with the spool. A pivoting lock bar extends across the length of the spool, having at least one pawl fixed at each end, to engage with the toothed wheel and with the ratchet respectively. The pawl on the spool side is arranged to be weaker than the other pawl so as to shear under a predetermined force to allow the spool to rotate and the torsion bar to twist.

Abstract: Force limitation in retractors is needed to avoid injury to an occupant from the seat belt itself particularly at high crash impact loads. The invention provides a seat belt retractor comprising a spool including force limiting means for allowing further payout of the seat belt webbing after the spool has locked, under the influence of an occupant's forward momentum in the crash condition.

Abstract: A vehicle sensor for a retractor for a vehicle safety restraint has a sensor mass in the form of an upturned hollow cup, formed in a single piece by injection molding or die casting, resting on an upstanding post. It may be of metal or high-density plastic material. Preferably a profiled pad is fixed or mounded on the underside of the lever or on the upper surface of the cup. In this way the arrangement causes the lever to lift through substantially the same angle whichever the direction of acceleration activating the sensor. This sensor is an improvement over known sensors because it is simpler and cheaper to manufacture, easier to calibrate relatively accurately, and does not exhibit right/left dependency.

Abstract: A load limiting device is used with a vehicle seat belt during a crash to allow a limited and controlled forward motion of a vehicle occupant after the retractor has locked. The load limiting device decreases the forces exerted by the seat belt on the vehicle occupant's torso. The load limiting device has a container which defines a flow path for a fluid, with a restriction in the flow path. An actuator is located within the container and is movable within the container under the action of a load transmitted to the seat belt webbing from the vehicle occupant under extreme acceleration conditions, to move the fluid through the restriction in the flow path to dissipate a predetermined portion of the load on the webbing.

Abstract: A load limiting device is used with a vehicle seat belt during a crash to allow a limited and controlled forward motion of a vehicle occupant after the retractor has locked. The load limiting device decreases the forces exerted by the seat belt on the vehicle occupant's torso. The load limiting device has a container which defines a flow path for a fluid, with a restriction in the flow path. An actuator is located within the container and is movable within the container under the action of a load transmitted to the seat belt webbing from the vehicle occupant under extreme acceleration conditions, to move the fluid through the restriction in the flow path to dissipate a predetermined portion of the load on the webbing.