Abstract: A seat belt retractor incorporating a force limiter to permit the restricted paying out of a seat belt webbing and a control mechanism for controlling the force limiting functions of the retractor. The arrangement includes a two part spindle within a retractor. On a first part of the spindle the safety belt is wound. A second part of the spindle is configured to be locked by a retractor locking device. The two spindle parts are interconnected by a belt load limiting torsion bar. The torsion bar has two sections of different torsional stiffness. The junction between the two torsion bar sections is releasably connected to part of the spindle. When the connection is present one energy absorbing level is provided and when the connection is controlled there is another energy absorbing level. The connection is broken in response to a relative movement between the two spindle parts caused by an initial belt force in excess of a predetermined force.

Abstract: An energy-absorbing force limiter for a safety device comprises a first component (5) and a second component (2), such as a seat-belt, that is moveable relative to the first component (5). The force limiter provides an energy-absorbing movement-resisting effect, for example by means of a frictional brake (4, 5), to resist movement of the second component relative to the first. An adjustable control element (6) actuates the brake. The magnitude of the frictional effect is a function of the degree of adjustment of the control element and at least one parameter, such as temperature, which influences the coefficient of friction. The control mechanism (9) adjusts the adjustable control element (6) to control the magnitude of the movement-resisting effect in response to a signal (12) representative of the desired resistance to movement together with a signal (10, 11) representative of that at least one parameter.

Abstract: A safety arrangement to provide protection for an occupant in a motor vehicle includes a seat-belt provided with a measuring device to measure energy absorbed by the seat-belt. The measuring device may determine the length of safety-belt paid-out after a retractor locks, the belt being paid-out against a force provided by a force-limiter. The energy absorbed is calculated and is used to control the vents of a ventable air-bag. The air-bag is vented if a substantial part of the energy of the occupant is absorbed by the seat-belt, but is not vented if a large proportion of the energy has not been absorbed by the seat-belt.

Abstract: A safety arrangement incorporates a seat-belt (3) to protect an occupant (2) of a vehicle seat (1). A control unit (11) incorporates a calculator (18) to calculate the weight of the occupant (2) of the seat occupant, by comparing the force (6) applied to the seat-belt by the seat occupant with the acceleration (14) of the compartment. A controller (19) controls a restraining force applied to the seat occupant by the safety-belt and, possibly, additional force limiting or energy absorbing devices such as an air-bag (8).

Abstract: A safety arrangement for detecting the position of an occupant (4) of a seat (1) which is provided with a safety belt (9) which is mounted on a retractor (10) includes a sensor (11) which measures the length of belt withdrawn from the retractor The sensor is associated with a processor unit (8) which is associated with a seat position sensor (7). By determining the position of the seat and by determining the minimum length of belt paid-out from the retractor (10) after the seat belt has been buckled in position, and by determining how additional belt has been paid-out at any incident, the position of the seat occupant (4) relative to an air-bag (19) can be determined. If the seat occupant is very close to the air-bag, the nature of deployment of the air-bag can be moderated by the central processor unit (8).

Abstract: A seat-belt arrangement including an energy-absorbing force limiter. A first component, for example in the form of a retractor reel spool is movable relative to a second component, for example the frame-work of the retractor. The spool carries with it elements presenting friction faces which co-operate with further elements carried by the frame. A stack of Piezo-electric elements apply a compressional force driving together the elements having the friction faces to provide a controlled frictional energy-absorbing effect.

Abstract: An energy-absorbing force limiter for a safety device comprises a first component (5) and a second component (2), such as a seat-belt, that is moveable relative to the first component (5). The force limiter provides an energy-absorbing movement-resisting effect, for example by means of a frictional brake (4, 5), to resist movement of the second component relative to the first. An adjustable control element (6) actuates the brake. The magnitude of the frictional effect is a function of the degree of adjustment of the control element and at least one parameter, such as temperature, which influences the coefficient of friction. The control mechanism (9) adjusts the adjustable control element (6) to control the magnitude of the movement-resisting effect in response to a signal (12) representative of the desired resistance to movement together with a signal (10, 11) representative of that at least one parameter.

Abstract: A safety arrangement to provide protection for an occupant in a motor vehicle includes a seat-belt provided with a measuring device to measure energy absorbed by the seat-belt. The measuring device may determine the length of safety-belt paid-out after a retractor locks, the belt being paid-out against a force provided by a force-limiter. The energy absorbed is calculated and is used to control the vents of a ventable air-bag. The air-bag is vented if a substantial part of the energy of the occupant is absorbed by the seat-belt, but is not vented if a large proportion of the energy has not been absorbed by the seat-belt.

Abstract: A seat belt retractor incorporating a force limiter to permit the restricted paying out of a seat belt webbing and a control mechanism for controlling the force limiting functions of the retractor. The arrangement includes a two part spindle within a retractor. On a first part of the spindle the safety belt is wound. A second part of the spindle is configured to be locked by a retractor locking device. The two spindle parts are interconnected by a belt load limiting torsion bar. The torsion bar has two sections of different torsional stiffness. The junction between the two torsion bar sections is releasably connected to part of the spindle. When the connection is present one energy absorbing level is provided and when the connection is controlled there is another energy absorbing level. The connection is broken in response to a relative movement between the two spindle parts caused by an initial belt force in excess of a predetermined force.