GB 1301766 A
1301766 Crash restraint bags NISSAN MOTOR CO Ltd 28 June 1971 [22 Dec 1970] 30095/71 Heading B7B [Also in Divisions F4 and G1] In a vehicular safety device including a crash restraint bag inflatable by means of liquefied gas 11<SP>1</SP> vaporized by firing an explosive charge 14 during a collision, an alarm circuit 23 for indicating when the amount of liquefied gas falls below the level necessary for full inflation of the bag is provided. The circuit may include a device 26 having a diaphragm 27 subjected at one side to the pressure of vapour above the liquefied gas and at the other to the sum of the pressure of the liquid due to its weight and the vapour pressure, the diaphragm being biased by spring 34. When the liquid level drops, due for example to leakage, the diaphragm moves to the left as shown and eventually the circuit 23 is completed when contacts 32, 33 close thus lighting a warning light 24<SP>1</SP>. The pressure sensing and comparing arrangement may be formed from pressure sensors which generate electric, hydraulic or pneumatic signals and a suitable differential pressure detector.