Patent GB-1380968-A (GB)
Title: Apparatus for detecting a collision of a vehicle
IPC: H01H35/14
Filed: 1972-02-29
Abstract: 1380968 Vehicle crash bags; bumpers NISSAN MOTOR CO Ltd 29 Feb 1972 [4 March 1971 28 May 1971 24 June 1971 25 June 1971 21 July 1971 23 July 1971 5 Oct 1971 25 Oct 1971] 9393/72 Headings B7B and B7J [Also in Division H1] Motor vehicle collision detectors for operating inflatable protective bags &c. comprise parts which are collapsible or frangible, whereby an electric circuit is opened or closed on application of mechanical forces above a predetermined magnitude.  Numerous embodiments are described in which the circuit is normally closed by a wire or strip (41), (44), Figs. 2, 3 (not shown), enclosed within a rubber or plastic sheath and mounted on a vehicle bumper &c. whereby the wire or strip is fractured. In others a carbon rod or a glass tube 56, Fig. 8a, coated with a conductor, is mounted in an insulating sheath 58 which may have a sharp projection, Fig. 7a (not shown), or be arranged to be sheared by mounting at the ends in a flanged block 62 enclosed by a presser member 61 which may be attached to the vehicle bumper (64), Fig. 9 (not shown). In other examples, the carbon rod or tube may merely be mounted on a deformable plastic cushion covered by a protective but deformable metal sheath, Fig. 10c (not shown), or may be annular and mounted in a space between rigid co-operating parts 84, 85, Fig. 12a, having shearable projections 84a which permit the rods or tubes 82 to be shattered on overload. In a further example, contact studs 93, 93<SP>1</SP>, Fig. 13a, mounted in an annular insulating sheath 91 are normally bridged by a ring conductor 89 on a plunger 90 which moves the shear projections 91a and open the circuit when an overload is applied. In other embodiments in which the circuit is normally open, strip like contacts 95, 95<SP>1</SP>, Fig. 14, with insulating spacers 96 may be mounted in an insulating flexible cover 97 or deformed into engagement with each other on impact. A device similar to the embodiment of Fig. 12a may hold a pair of annular conductors apart until a part of a casing member is sheared to bring the contacts together. In another embodiment a pair of annular contacts 108, 108<SP>1</SP>, Fig. 17a, are held apart in an insulator 109 surrounding a flanged tube 110a. On impact the tube 110a collapses and the contacts are permitted to deflect into engagement, Fig. 17b (not shown). In a further example a plunger 120, Fig. 19, mounted under a frangible or deformable cover 122 of housing 116a moves to closed contacts 117a, 117b when an impact is large enough to deform the cover 122 and shear a holding pin 121. The collision detectors may be mounted on a part of the vehicle frame in alignment with the vehicle bumper for engagement thereby during a collision. Alternatively the detector may be mounted on a bar 146b, Fig. 26, which is automatically moved forward of the bumper 140 on electric motor driven telescopic mountings 143, 144 when predetermined speeds are reached whereby a crash signal is received to operate the inflatable bag before the impact on the bumper 140 takes place. Numerous electric circuits systems are described whereby the impact detector as (151), Fig. 30 (not shown), may be used in conjunction with low impact sensitive inertia detectors (150) to render the detectors (151) inoperative under low impact conditions. In the embodiment shown a timer (154) operates a switch (155) in series with the detectors (150), (151) to prevent the inflatable bag actuator (153) from being operated if the high impact detector (151) is not operated within a preset time following the initial impact of detector (150) as would occur under light collision conditions.