Fire-prevention device for vehicles,boats and other means of transport equipped with electromechanical apparatus

Abstract

 The invention concerns a fire prevention device for vehicles and boats that deactivates the main uses of the electrical system in the event of impact, thus preventing the possibility of fire due to possible fuel leakage caused by operation of the fuel pump after the impact.
The response of the invention is also irrespective of the direction from which the impact comes.
The electrical system is brought into use again only when the user so desires, in a simple, practical manner, inside the vehicle.

Description

[0001] The invention concerns a safety device for electrical systems installed on vehicles and boats.

[0002] Serious fire risks are known to exist in the event of accident, due largely to failure to disconnect the electrical system: leakage of fuel due to failure of the fuel pump to shut down while sparks and overheating can be produced can start fires with very serious consequences both for any trapped occupants and for the vehicle or boat itself

[0003] Safety devices capable of overcoming this problem have long been sought. A good result has been achieved with the device illustrated in patent application MI 92A001835 which comprises an insulating casing, two conductor bars having silver-plated contacts built into the bottom of the casing at a distance from each other, connected by a low current fuse, an inertial mass that can be moved sideways in the casing, and is held in a central position by means of radial springs. Said central mass comprises a conductor disk that is pressed against the contacts of the conductor bars by a spring-loaded push rod sliding in a core or support, against the action of a lower elastic element. An electromagnet housed in the casing, when it is supplied with electrical current, keeps the core in a lowered position against the action of a return spring, which is generally conical spiral spring, whereas when it is not supplied the action of the conical spring prevails, lifting the core and the push rod.

[0004] An impact, particularly a horizontal impact, moves the inertial mass and the conductor disk separates from the contacts of the conductor bars, partially disconnecting the electrical system; the fuse connection between the conductor bars in fact allows low-consumption devices (parking lights etc.) to use the electrical system. Subsequently, by disconnecting the electromagnet, the core and the push rod are raised allowing the conductor disk to be repositioned centrally through the action of the radial springs.

[0005] This safety device, therefore, unlike its predecessors, does not require manual resetting of the centered position of the inertial mass on the device itself. Moreover, it presents the following advantages: it causes the engine and relative fuel pump to stop immediately in the event of a violent impact; in the event of irreversible damage to the electrical system, it cuts off the electrical current for good; it is safe, easy to use and of minimum size.

[0006] Nevertheless, the presence of radial springs (four in the case of the above patent) that keep the inertial mass in the centered position and serve to reposition it after the impact, does not guarantee a homogeneous response of the device for every possible horizontal direction of impact.

[0007] An object of the present invention is to create a safety device, again operating through inertia, that maintains the advantages of the above patent and has a uniform response for every horizontal impact, irrespective of the direction from which it comes.

[0008] The object has been achieved with a device as claimed in claim 1; further innovative characteristics are stated in the subsequent claims.

[0009] In brief, the new device comprises a casing of insulating material incorporating in its base two conductor bars, having silver-plated contacts, and joined electrically by means of a low current fuse, a disk of conductive material that can move between a position in which it makes an electrical contact between the two bars and a position at a distance from them in which it does not establish said contact, said disk being kept in a centered position in the casing by means of an elastic plate disposed between the bars and ending in a convex appendix that fits into a concave seat provided in the center of the undersurface of the disk. A push rod pressed by a spring towards the bottom of the casing engages with a protuberance placed at the centre of the upper surface of the disk and keeps the disk in a state of contact against the contacts on the bars, whereas in the event of impact said disk is forced into the position out of contact by the above mentioned elastic plate disposed between the bars and acting in opposition to the push rod. An electromagnet co-operates with a core or support which receives said push rod and relative spring in a hollow along its axis; when electrical current is supplied to the electromagnet it keeps the core lowered to allow efficient pressure by the push rod against the conductor disk, when current is not supplied it allows the core to rise with the relative push rod under the action of a spring; raising of the push rod allows the conductor disk to be repositioned in a centered position, exploiting the shape of the above mentioned contact surfaces between the disk and the elastic plate. It should further be noted that when the vehicle is stationary after impact, electrical current is supplied only through the fuse, increasing the safety of the persons transported, as well as that of the vehicle or boat.

[0010] Even with the vehicle stationary and the engine turned off the device permits complete safety from any possibility of fire due to unforeseeable causes such as a short circuit of the electrical system or other intrinsic causes.

[0011] This new device is also safe, easy to use and of minimum size, it maintains the advantages of the previous device and in addition the horizontal direction of the impact is irrelevant as far as the response of the device is concerned.

[0012] An embodiment of the invention of a non-limiting nature will be described below with reference to the attached drawings in which:

Figure 1

is an exploded perspective view of the device;

Figure 2

is an axial vertical section through the device in operating conditions during normal running, enlarged with respect to actual size;

Figure 3

is an illustration of the device in figure 2, in a section taken along an axial plane at right angles to the plane of said figure;

Figure 4

is a section similar to Figure 2 and illustrates the device as it is disposed after having received an impact with a horizontal component;

Figure 5

is a section along the same plane as Figures 2 and 4 and illustrates the device as it is when the electrical supply to the electromagnet is cut off to permit resetting of the device itself;

Figures 6 and 7

show a modified embodiment of the device, said modified embodiment being drawn in sectional views like figures 2 and 3, in the same conditions as shown in said figures.

[0013] The device is indicated as a whole by reference number 1.

[0014] It comprises an insulating casing 2 that forms a housing 3 on the inside and in the bottom wall of which are incorporated two power supply bars, respectively 4 and 5. A terminal 6 is fixed to the bar 4 or 5 in an electrically conductive manner. Each bar, in the portion on the inside of the casing and integrally with the bottom of it, bears one or two conductive pads or rivets 7. The space 3 has a lower part 3' with a smaller diameter and an upper part 3'' with a larger diameter, forming an annular shoulder 8.

[0015] In the space between the conductor bars, a disconnecting contact plate 9 rises from the bottom of the casing, consisting of an elastic conductive blade ending in a convex appendix 10 and electrically connected to a conductor cable 11. Above the plates 9 and the pads 7 is placed a self-centering disk 12 of conductive material that is received in the part 3' of the space in the casing and is free to oscillate horizontally; that is to say, the disk 12 has a smaller diameter than the diameter of the part 3' of the space. The disk 12 has a concave seat 13 in the middle of the undersurface, in which seat the convex part of the contact plate 9 engages, keeping it centered during normal running of the vehicle or boat. Said disk 12 also has a circular channel 14' on the upper surface which centrally defines a protuberance 14 the upper surface of which is level with the surface of the disk around the channel. The height of the disk at the protuberance is called h. The height of the space 3' from the surface of the pads 7 at the shoulder 8 is h + s so as to permit an axial movement s of the disk.

[0016] The concave seat has a substantially frustoconical shape, with the bottom rounded, and the base rim of the seat has a radius R that is greater than the radius r of the appendix 10. There is little friction between the contact surfaces of the seat and the appendix 10.

[0017] An intermediate bottom 15 is disposed on the shoulder 8. A solenoid or electromagnet indicated as a whole by 16 is placed on it, its coil, indicated by 16', being wound on a body 16''. Reference number 17 indicates an annular body called "magnetic continuity ring". The electrical supply cables of the solenoid are indicated by 18 and 19. It should be noted that the cable 11 in the direction of the coil, connected to the plate is passed in a suitable semicircular seat of the ring 17, so that it leaves the casing from the same opening as cables 18 and 19.

[0018] The body 16' of the solenoid is preferably shaped to widen at the top into a cap on which a conical spiral pressure spring 20 rests, which acts between an upper disk-shaped plate of the winding body 16" of the solenoid and a disk-shaped part 21' of a core 21 that can move inside the solenoid along its axis (coinciding with the axis of the casing). The core 21 is hollow on the inside and has a cavity 22 with a larger diameter and a terminal hole 21 with a smaller diameter. The hollow 22 receives the head 24' of a peg or push rod 24 that is axially movable inside the hole 23 and is pushed to a condition wherein it extends from the hole by means of a spiral pressure spring 25.

[0019] A threaded dowel 26 engages in a suitable thread in the hollow 22 and closes it, acting as a support for the spring 25.

[0020] A spacer ring 27 placed around the tray-like part of the solenoid body serves as a protection and provides an upper stop for the stroke of the core 21. Obviously this stop could be provided by separate elements.

[0021] Screws 28 fix together a cover 29 (possibly equipped with a heat dissipator 30), the spacer ring 27 and the casing.

[0022] The latter, generally on a side opposite the bars, may comprise a seat 31 open to the outside, in which terminals 32 are received, generally of the spring type (figure 3), each electrically connected to a respective bar 4 or 5; a fuse (not illustrated) may be placed between the terminals.

[0023] The device must be assembled so that the disk 12 is substantially horizontal and must be connected to the terminal of the positive pole of the vehicle or boat battery by means of the terminal 6 and with the general electrical supply cable by means of the bar 5. Cables 18, 19 supplying the electromagnet are connected to the engine ignition block. The wire 11 is connected to the ignition power supply.

[0024] Under normal running conditions, illustrated in figures 2 and 3, the disk 12 is kept centered thanks to the convex appendix 10 of the contact plate engaged in the concave seat 13 of the disk itself the protuberance 14 is in contact with the push rod 24. The force of the spring 25 overcomes the force of the elastic contact plate 9 and therefore the conductor disk 12 is kept in contact with the pads 7: an electrical continuity is established between the bars 4 and 5 and the circuits connected to them.

[0025] In the event of an impact from any direction, the disk 12 undergoes a horizontal movement with respect to the axis of the push rod, a movement which, however, does not exceed the radius R of the horizontal projection of the concavity 13, and, no longer being opposed by said push rod, it is thrust by the plate 9 against the bottom 15 breaking the electrical continuity of the bar 4 and 5. The push rod in turn, being unopposed, is pushed to protrude to the maximum extent by the spring 25 (figure 4). This actually prevents the device from being reset without the intentional intervention of the driver of the vehicle. The battery current therefore passes through the fuse which allows only low intensities, such as that required, for example, by the parking lights. A larger electricity requirement breaks the circuit.

[0026] When the electrical circuit is broken the current is disconnected from the circuits that supply the engine ignition and the fuel pump: therefore the engine is stopped and at the same time, by stopping the pump, any possible escape of fuel is prevented from setting the vehicle on fire.

[0027] The current to the electromagnet 16 must be cut off for resetting to take place: this may be done, by the driver through a control on the dashboard, when suitable. The conical pressure spring 20 then raises the support 21 which in turn raises the push rod 24 (figure 5). With the latter in a position protruding slightly or not at all from the bottom 15, the action of the elastic plate 9 because of the shape of the contacting concave surface 13 and convex surface 10, creates a horizontal component that returns the disk 12 to the centered position, with the projection 14 on the vertical axis a of the casing and the push rod.

[0028] When electricity is again supplied to the electromagnet 16 this causes the core 21 to be lowered against the action of the spring 20, the push rod 24 again pushes the conductor disk 12 into electrical contract against the conductor bars 4 and 5, overcoming the elastic force of the plate 9.

[0029] In figures 6 and 7 a modified embodiment of the device is shown, which is indicated on the whole with reference numeral 101. Portions of the device 101 which are identical to the corresponding ones of the device 1 have the same reference numerals and will not be described in detail.

[0030] The device 101 has a further spring 125 acting on the push rod 24, between the head 24' thereof and the bottom 15, in contrast with respect to the spring 25 and the spring 20. The spring 125 is weaker than the spring 25. Such an arrangement has the advantage of allowing a more uniform setting in the devices.

[0031] Furthermore the conductor bars 4 and 5 of the device 101 are buried in the material of the housing 2, so as to have an insulating coat above then. Preferably the plate 109 is placed in such a way that the cable 11 thereof could have the shortest run up to the housing outlet hole.

[0032] Finally the device 101 lacks of the heat dissipator 30 and the cover is built in one piece with the ring and indicated with 127.

Claims

1. A fire-prevention device for vehicles and boats comprising:
an insulating casing (2);
two conductor bars (4, 5) in the insulating casing positioned at a distance from each other;
a conductor disk (12) constituting an inertial mass having a ring-like channel that defines a protuberance (14) at the centre of the upper surface, said disk having a smaller diameter than the diameter of the space that receives it and being moveable between a position in electrically conductive contact with said bars and a raised, sideways shifted position out of contact, through opposing actions of means (24,10) pushed by elastic elements (25, 9), the action of one (24) of said means pushed by elastic elements being under the control of an electromagnet (16)
characterized by the fact that the disk (12) on the surface opposite the channel and the other (9) of said elastic means have co-operating concave and convex surfaces.

2. A device according to claim 1 characterized by the fact that the conductor disk (12) has on its undersurface a concave seat (13), and said other elastic means is an elastic plate (9) with a convex appendix (10).

3. A device according to claim 2 characterized by the fact that the concave seat has a substantially frustoconical shape with a rounded tip, with a base radius R, and the convex appendix (10) has a base radius r that is smaller than R.

4. A device according to claims 1 and 3 characterized by the fact that the sideways movement of the disk between the position in electrical contact and the position out of contact does not exceed the radius R of the concave seat.

5. A device according to claim 1 characterized by the fact that the conductor bars (4, 5) are connected together through a fuse.

6. A device according to claim 2 characterized by the fact that the elastic plate or blade (9) is electrically conductive and is connected to a conductor cable (11).

7. A device according to claim 1 characterized by the fact that said first means pushed by an elastic element is a push rod (24) that moves along the axis of the device and is engaged in a core or support (21) of an electromagnet (16) and a pressure spring (20) acts between it and the coil, biassing said elements away from each other.

8. A device according to claim 1 characterized by the fact that the casing has a lower space (3') that receives said conductor disk (12), and is defined superiorly by a bottom; said lower space having a greater height than the height of the conductor disk (12) at the protuberance (14).

9. A device according to claim 7 characterized in that said pushing elastic elements for said push rod (24) comprise a spring (25) acting to bias the push rod to project from the core.

10. A device according to claim 9 characterized in that said pushing elastic elements for said push rod comprise a second spring (125) acting between the push rod (24) and a bottom (15) in the housing, in contrast with respect to the above mentioned springs (25 and 20).

Drawing