Abstract: A U-shaped frame for a seat belt retractor has two spaced arms made from a material of a predetermined thickness and having a cutout in the material of each arm for receiving a lockbar. Each cutout has an edge comprising a land portion for supporting the lockbar, which land portion is of a reduced thickness compared to the thickness of the material of the arms, to present a reduced surface area to the lockbar. The frame may be of pressed steel and the lockbar of die-cast non-ferrous material.

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 U-shaped frame for a seat belt retractor has two spaced arms made from a material of a predetermined thickness and having a cutout in the material of each arm for receiving a lockbar. Each cutout has an edge comprising a land portion for supporting the lockbar, which land portion is of a reduced thickness compared to the thickness of the material of the arms, to present a reduced surface area to the lockbar. The frame may be of pressed steel and the lockbar of die-cast non-ferrous material.

Abstract: A calibration spring tension adjuster for a seat belt tension sensor has a calibration spring, and a holder. The fixed part and the movable part are adjacent to each other and comprise mutually facing stepped helical faces arranged so that the movable part can be rotated relative to the fixed part causing the steps to slide over each other causing a gap between the stepped faces to increase and compressing the spring. The steps can be arranged so that movement of the movable part in one direction is resisted. The holder is arranged to attach to the fixed part and the spring is held between an abutment face of the holder and a non-stepped face of the movable part.

Abstract: A calibration spring tension adjuster for a seat belt tension sensor has a calibration spring, and a holder. The fixed part and the movable part are adjacent to each other and comprise mutually facing stepped helical faces arranged so that the movable part can be rotated relative to the fixed part causing the steps to slide over each other causing a gap between the stepped faces to increase and compressing the spring. The steps can be arranged so that movement of the movable part in one direction is resisted. The holder is arranged to attach to the fixed part and the spring is held between an abutment face of the holder and a non-stepped face of the movable part.

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: A webbing guide for a vehicle safety comprises a guide surface in the form of a generally cylindrical bar (6) which has a continuous outer surface over which seat belt webbing passes in use following an upside-down U-shaped path. The surface comprises a top portion and two side portions (8) on either side of the top portion, and the top portion and at least one of the side portions are shaped so as to present a countered surface to the seat belt webbing. Preferably, the central area (7) of the top portion is raised, and the central area (9) of one or both side portions (8), is recessed, but the opposite contour arrangement could be provided with the central area of the top portion recessed and the central area of one or both side portions raised.

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 webbing sensor for a vehicle safety restraint retractor. The sensor comprises an inertial member, mounted for rotation coaxially with a retractor spool, a pawl for engaging the spool and locking it against rotation under emergency conditions, and a calibration spring biasing the inertial disc so that it tends to rotate with the spool unless there is a sudden acceleration or deceleration of a value such as to overcome the resilience of the spring. The spring is connected to the spool via the pawl so that relative rotation between the disc and the spool results in movement of both ends of the spring, preferably by approximately the same distance. Throughout the locking procedure, the spring force remains substantially constant and thus the bias torque on the inertia disc remains substantially constant, and the locking performance of the sensor is improved.

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 retractor for a vehicle safety restraint which comprises web locking wedges (49a, 49b) which grip the seat belt webbing (19), under certain predetermined load conditions, so as to more securely restrain the vehicle occupant at the beginning of a crash pulse and which includes a load limiting arrangement so as to allow a limited and controlled pay out of webbing at the beginning of the crash pulse. The web locking retractor thus comprises a wedge (49a, 49b) which has an inner gripping surface with a predetermined coefficient of friction relative to the seat belt webbing so that, at a predetermined loading, the webbing slips past the friction surface of the wedge. This may be achieved by using double thickness webbing along a predetermined portion of the seat belt, for example two layers of webbing, or coating the wedge or a part of the webbing with a material (322) which is erodible or deformable and which may be cut into or eroded by the friction surface of the wedge, or by teeth (320) on that surface.

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.