Abstract: An electric switch 11 has contacts 12 and 13 which are initially closed by activating means 14. The invention provides urging means 22 to bias the switch against reopening of the contacts during at least an initial period which is useful if the activating means does not operate for long enough for the electric switch to assume its stable closed position. The urging means is responsive to current carried through the contacts. It is possible to provide a plurality of switches responsive to the same urging means, different switches being provided for different electrical circuits and possibly energised from different sources.

Abstract: An inertia body moves from a rest position in response to an applied acceleration and in so doing operates an electrical switch remote from the rest position. The body moves on spaced rails of a track arranged in a plane, with an aperture between the rails so that the body can extend below the running surfaces of the rails. The plane may be inclined and/or the rails may be non-parallel so that the center of gravity of the body rises as it moves from the rest position.

Abstract: A ferromagnetic ball is mounted between dished first and second contacts and subjected to magnetic restraint tending to retain the ball in its central, rest position by means of a rare earth type magnet which is accurately positioned relative to the ball by a polyester shim clamped between the first contact and the magnet as a result of resilient deformation of an annular portion of a cap attached to a housing member enclosing the first and second contacts. Lugs extending from the first and second contacts pass through openings in the housing member and through apertures in a printed circuit board to which the sensor is attached by dowels. The lugs are then attached to the printed circuit board by soldering.

Abstract: Movement of an inertia mass (4) from a rest position as a result of acceleration or deceleration in excess of a given threshold value causes a hinge-like assembly (8) having two parts (9 and 10) to pivot between two overcenter positions on either side of a center position in which the two parts (9 and 10) occupy a common plane to thereby cause movable electrical contacts (14 and 15) forming part of the hinge-like assembly (8) to engage or separate from further electrical contacts (31 and 32).

Abstract: The inertia switch device (1) comprises an inertia mass (6) which is movable from a rest position when the device is subjected to an applied acceleration or deceleration in a horizontal plane, a first electrical contact (5) movable between a first stable position in which it engages a second electrical contact (3) and a second stable position in which it no longer engages the second electrical contact, and support means (4) having a bifurcated portion (24) for carrying a bifurcated portion of the first electrical contact (5). An operating means (27) is struck by the inertia mass (6), when the applied acceleration or deceleration exceeds a threshold value and moves the first electrical contact (5) from the first to the second stable position. The operating means (27) has a first limb (31) which is struck by the inertia mass and a second limb (28) with a bifurcated portion which is pivotally mounted on the support means.

Abstract: An inertia switch having an inertia mass, in the form of a ball resting in a conical seat, which mass is responsive to applied acceleration or deceleration in any direction in a horizontal plane and is arranged to operate changeover electrical contacts connected in an electrical circuit for unlocking the electrically operated door locks of an automobile.