Safety device with an inflatable cushion which provides effective protection during successive collisions

Claim 1

A safety device for protecting a passenger in a moving vehicle including successive impacts, which comprises at least one inflatable cushion, said cushion comprising two adjacent noncommunicating chambers, maintained at different pressures at the time of use, the outer chamber enclosing at least partially the inner chamber, the inner chamber being capable of communicating with the atmosphere via permanent orifices of low cross-section, and via temporary orifices of large cross-section, the latter being closed by valves which open only in the direction which admits air into said inner chamber, the outer chamber being connected to a source of gas under pressure, a collision detector controlling the actuation of said gas, the walls of said two chambers being of flexible material of substantially equal dimensions and located one inside the other, connected together in a discontinuous manner by leakproof contact zones distributed over a substantial area of said walls, said permanent and temporary orifices being machined at said leakproof contact zones, the outer chamber expanding and re-expanding the cushion when it is pressurized, the inner chamber being expanded by pressurization of the outer chamber and being pressurized itself by sucking in air from the surrounding atmosphere via the temporary orifices of large cross-section, the inner chamber being depressurized by escape of air through the permanent orifices during the stage when the passenger presses against said cushion, the gas passage taking place at a low flow rate in the direction from the interior of the inner chamber to the surrounding atmosphere, for the purpose of deadening the person to be protected when the latter is thrown against the said cushion during an accident, and at a higher flow rate in the direction from the surrounding atmosphere to the interior of the inner chamber for the purpose of rapidly re-inflating the said cushion as soon as the latter is no longer acted upon by the person to be protected.