ACOUSTIC APPARATUS FOR SELF-DETERMINATION OF POSITION This apparatus has been first designed in order to face the frequent and urgent need to quickly determine the position of vehicles after an accident, often capsized in a ravine or in similar situations in which it is difficult to determine the exact position in order to direct timely assistance and, if it is the case, salvage the vehicle.

There is a number of theoretically possible means for signalling, unfortunately not always feasible, as the GPS radio signal, because it is not already diffuse enough, or light signal, because it can be screened by interposition of means as rocks or trees.

Apart from any specific apparatus available to any particular rescue operator, the only feasible means is the acoustic signal; if properly tuned, an acoustic alarm can be heard even at distances of hundreds of metres from the emission point.

The original idea for which a patent is required is an apparatus (fig. 1) able to determine-in an autonomous and automatic way-its own position with respect to gravity field, by responding to rotations with respect to the initial reference axes. In addition, when the position itself exceeds a certain threshold of angular regulation of the apparatus, an alarm system is switched on, as an example, an acoustic variable frequency piezoelectric alarm (fig.

2).

Such apparatus is self-protected against shocks and crush as well as fire, for a determined length of time. In fact, it is contained in a double steel cylinder, which can be made more or less resistant by simply varying the thickness of walls; in addition, it is made fireproof by means of a both inner and outer insulation, by varying which one can determine the adequate time of fire resistance, for the desired final result.

The source of electric power consists in a battery 12V or 24V DC, of small size and power, working at the same voltage as that of the vehicle, continuously recharged by buffer battery by the same recharging system.

An appropriate control electric circuit denies recharge access and voltage return towards the power source; such a system is essential in order to make the apparatus completely autonomous in case of faults or interruption of the recharge system. For instance, in case of breakage following an accident, a simple fuse makes even safer the recharge power supply system.

The apparatus is connected by a gravity switch, as a sphere or a mercury switch, such that it can connect the power circuit in case the switch itself rotate of a given amount with respect to the original axes in steady state (fig. 3, fig. 4).

A system of two relays switches on the acoustic alarm ; the sound comes out through the holes drilled on the two circular bases of the cylindrical container. To increase efficiency one can use two switches and/or two alarm emitters, in all possible configurations, as shown in fig. 6 and fig. 7.

Some relevant safety and assembling peculiarities are: o Resistance to distortion and perforation of cylinder, below the mechanical threshold determined by construction; o Resistance to ignition by hydrocarbon fuels for the time length determined by construction; o Double siren located over the two bored cylinder bases; o Functionality even if submerged and without time limits, apart from those owed to battery duration; o High power autonomy, almost a couple of hours, because of parameters of available power supply and power absorption of the working apparatus; o Electric circuit wired with mineral fireproof cables; o Very low probability of inner short-circuit and preventing protection with fuse; o Welded contacts, not mechanically modifiable by shocks; o Lack of printed circuits and other kinds of flammable contacts that can be made useless because of high temperature, beyond the given time limit; o Electrical system of power supply, position determination and control to be fitted into an resin agglomerating capsule, fireproof for a given time and waterproof for an indefinite length of time;

Apparatus test activation and de-activation by two test buttons, accessible from outside the capsule, but located inside the capsule, in order to avoid the involuntary activation; Possibility of multiplying the number of activation contacts, to be completely sure of the apparatus efficiency, as a number of gravity switches located along different axes; Alarm emitting the international SOS signal, 3 lines, 3 dots, 3 lines, appropriately spaced in time, with frequency and acoustic pressure to be regulated in phase of construction; Possibility of testing anytime the efficiency status of the apparatus, by a Led; Possibility of easily locating the apparatus in the bonnet or in other similar position, even in a place not mechanically protected; Total electric power of apparatus not significant with respect to that of the vehicle itself during the recharge phase, and null once activated, in the worst situation; Possibility of recharging also through an external means, from the ordinary home power supply; No maintenance, apart from a periodical test of efficiency.

Functional summary of controlled positioning circuit The functional aim is to make the piezoelectric siren go immediately after the vehicle capsizes - also partially-with respect to its initial position, steadily horizontal over all four wheels.

The siren is connected with the power source BA, battery 12V DC 5 Ah, by a contact NA of the relay R2, and controlled by the impulse codifier relay R3 (fig. 7 and fig. 8).

The relay R2, and then the relay R3, are activated by the positioning relay RI, in its turn switched on by the gravity switch INT and kept in excitation state by the auto-keeping system through a contact located inside the relay itself Once activated, the electric system can be reset to zero and shut down in ordinary conditions only by the button PA of the power circuit of the relay R2 solenoid; obviously, the system also stops if it is destroyed or if the power source runs out.

The power source BA is constantly kept charging by the recharging buffer system of the vehicle; the system of diodes D1 and D2 protects the apparatus from voltage return.

The system can be activated by hand and tested by the test button PE, and deactivated by the button PA; buttons are located below the container surface so that one can press them only intentionally; only the activation button can be also made accessible to the driver, by positioning it inside the vehicle.

Ordinary functioning, that is the vehicle emergency state, is determined by activation of the rolling sphere gravity switch INT; this switch connects two contacts located inside the switch itself and closes the control circuit of relay RI.

The switch INT provides a number of possible contacts, all in parallel over its spherical outer part, for increasing functionality and for any angle with respect to horizontal, from the minimum non-intervention angle, here hypothesized being about 45°.

One activation impulse is sufficient to make the siren go, until it is deactivated by hand, independently from the following state of the vehicle, which could also set back in the initial state, that is with all four wheels on the ground.

Main electric and mechanic features of components Container : cylindrical shape, made in double steel sheet, minimum thickness mm 3, double walls circular bases with holes mm 2 wide.

Insulation : rock wool or ceramic fibre in the outer side and 10 cm longer than the cylinder; inner filling with ceramic fibre of fireproof resin.

Battery : no liquid solutions, no maintenance; 12V-SAh.

Power relay : capsule relay, 12V DC, 10A.

Codifier relay : capsule relay, 12V DC.

SirenJsirens : closes the circuit between piezoelectric siren, emission frequency 500 Hz; sound pressure almost 100 dB.

Contact system : pressure contacts, subsequent welding; fireproof mineral cables.

Test and deactivating buttons : miniaturized buttons; 12V-6A.

Externalfuse : only into the recharge circuit; 12V-SA.

Internalfuse : 12V-10A.