Anti-theft device

Abstract

 A fuel dispensing unit for filling the tank of a vehicle with fuel is connected to a current source having an earth fault breaker and comprises at least one tamper/damage-detecting sensor. The sensor is arranged to activate with its sensor signal an electrical system, arranged to cause an earth fault releasing leakage current.

Description

Field of the Invention

[0001] The present invention relates to a fuel dispensing unit for filling the tank of a vehicle with fuel, the fuel dispensing unit being connected to a current source having an earth fault breaker, and comprising at least one tamper/damage-detecting sensor.

Background Art

[0002] Various techniques are available on the market to protect fuel dispensing units in case of burglary and other tampering for the purpose of steeling fuel. An example of such a technique is an anti-theft system with some kind of tamper/damage-detecting sensor, which breaks a switch which thus gives or breaks a signal between the fuel dispensing unit and a central unit which then loses contact with the fuel dispensing unit. The loss of this contact initiates some kind of alarm and inactivates the fuel dispensing unit, which serves to prevent use of the fuel dispensing unit. Inactivation involves, for instance, setting a logic variable in the control system of the pump at a certain value so that that pumping is not allowed or, in a mechanical control system, activating a mechanical stop which physically prevents pumping.

[0003] A drawback of the above-described anti-theft system is that it can relatively easily be tampered with so as to allow theft of fuel. By existing components being bypassed, joined with tape, broken to pieces or replaced with other components, the fuel dispensing unit can be started so that theft of fuel can take place. A further problem is that the system can be tampered with so as to be reset and thus not indicate that undue use has been made.

Summary of the Invention

[0004] The object of the present invention is to provide a fuel dispensing unit with an improved anti-theft system in relation to prior art, which is easily mounted and makes unlawful pumping of fuel difficult.

[0005] According to the invention, this object is achieved by a fuel dispensing unit which has the features as defined in claim 1, preferred embodiments being stated in dependent claims 2-10.

[0006] The new fuel dispensing unit is thus provided with a sensor-activated system, which causes a leakage current to release the earth fault breaker of the fuel dispensing unit current source. The fuel dispensing unit provided according to the invention is extremely advantageous by being put in a dead state owing to the fact that the external power supply ceases when one or more sensors detect that the fuel dispensing unit is opened, broken up or being exposed by some other kind of tampering.

[0007] In a preferred embodiment, the use of a combination of several light, pressure, magnetic, vibration, voltage, motion and/or mechanical sensors makes it very difficult to avoid interruption of the external power supply in case of undue breaking up of the fuel dispensing unit.

[0008] Each fuel dispensing unit is suitably arranged with a data storage unit which saves information if and when the external power supply is interrupted so as to make it still more difficult for undue use to pass unnoticed.

[0009] In a variant of the invention, the leakage current causing system is provided with an indicator for faulty connection of the system, and in another variant the system is provided with an indicator to indicate that the system is not switched on. Both variants facilitate correct mounting, after-equipment and/or service of the fuel dispensing unit.

[0010] The leakage current causing system is preferably arranged internally in the fuel dispensing unit for easy mounting and provides by its construction cost-effective protection which is also easy to arrange later on existing equipment.

[0011] By suitably providing the fuel dispensing unit with a voltage monitor, power failure is detected, which then allows one or more external alarms to be switched on and possibly call in security staff, service staff etc.

[0012] Another advantageous effect of the invention is that it also provides current carrying protection for, for instance, vehicles bumping into the fuel dispensing unit or for service staff forgetting to switch off the voltage. The invention makes it difficult to deform or open the fuel dispensing unit without the external current supply being switched off.

Brief Description of the Drawing

[0013] The invention will now be described in more detail with reference to the accompanying drawing which by way of example illustrates a currently preferred embodiment of the invention.

[0014] Fig. 1 is a schematic view of the principle of the invention.

Description of Preferred Embodiments

[0015] The fuel dispensing unit 1 shown in Fig. 1 for filling the tank of a vehicle with fuel is connected to a power source 2 having an earth fault breaker and comprises at least one sensor 3 which indicates some kind of tampering with the fuel dispensing unit 1. Examples of tampering can be breaking up or boring through the housing of the fuel dispensing unit, breaking the connection between the fuel dispensing unit and its central unit etc. A first circuit 4 is arranged inside the fuel dispensing unit 1 and connected between a phase conductor P and a protective earthing conductor PE and comprises a switch 7, which can be, for example, a magnetic sensor, and a resistor 8 connected in series. The first circuit 4 is usually designed to conduct a current (leakage current) greater than 30mA.

[0016] A second circuit 9 is connected between earth 10 and a voltage unit 11 in the fuel dispensing unit 1 and comprises, connected in series, a switch 12 and a relay 13 which controls closing and opening of the switch 7 in the first circuit 4. The switch 12 is closed by means of the sensor 3. In the preferred embodiment, the switch 12 is connected in parallel with other switches which are each controlled by a combination of other sensors, such as light, pressure, magnetic, vibration, voltage, motion and/or mechanical sensors.

[0017] A detector 14 is connected to the sensor 3 and detects and in some known way produces a signal if the sensor 3 is not activated or if the second circuit 9 is not connected to the voltage unit 11. An example of an effect of such a produced signal is the switched-off display lighting of the fuel dispensing unit. Arranged inside the fuel dispensing unit are on the one hand a data storage unit 15 which stores data if and when voltage failure over the fuel dispensing unit occurs and, on the other, a voltage monitor 16 which in case of voltage failure emits a signal to, for instance, an alarm.

[0018] Connected to the first circuit 4 is a circuit which detects and indicates with a light-emitting diode if the first circuit is not correctly mounted on the conductors P and PE of the current source 2.

[0019] With a fuel dispensing unit according to the preferred embodiment, a sensor is activated, for instance, when breaking up the outer housing of the fuel dispensing unit. Then the sensor closes the second circuit, which causes the first circuit to be closed, which in turn produces leakage current between the phase conductor and the protective earthing conductor, which are arranged between the current source and the fuel dispensing unit. When the leakage current arises, the current source interrupts the current supply, which makes it impossible to dispense fuel from the fuel dispensing unit.

[0020] A variant of the invention is to control the switch 12 by a combination of several different types of sensors, such as light, pressure, magnetic, vibration, voltage, motion and/or mechanical sensors. A further variant of the invention is that the first circuit 4 conducts current from the phase conductor P in a manner different from that described and causes a difference, usually greater than 30mA, between the electric currents of the phase conductor and the neutral conductor.

[0021] Finally it should be emphasised that the invention can be applied to protect many different types of devices supplied with voltage.

Claims

1. A fuel dispensing unit (1) for filling the tank of a vehicle with fuel, the fuel dispensing unit being connected to a current source (2) having an earth fault breaker, and comprising at least one tamper/damage-detecting sensor (3), characterised in that the sensor (3) is arranged to activate, by its sensor signal, an electrical system arranged to generate an earth fault releasing leakage current.

2. A fuel dispensing unit as claimed in claim 1,
characterised in that the sensor (3) is a light, pressure, magnetic, vibration, voltage, motion and/or mechanical sensor.

3. A fuel dispensing unit as claimed in claim 1 or 2, characterised in that the fuel dispensing unit comprises a data storage unit (15) for the earth fault release data of the fuel dispensing unit.

4. A fuel dispensing unit as claimed in any one of claims 1-3, characterised in that the fuel dispensing unit comprises a detector (14) arranged to detect an inactive sensor and, in case of sensor inactivity, indicate this.

5. A fuel dispensing unit as claimed in claim 4,
characterised in that the detector is arranged for indication by means of switched-off fuel dispensing unit display lighting.

6. A fuel dispensing unit as claimed in any one of claims 1-5, characterised in that the leakage current causing system comprises an indicator for incorrect installation of the system.

7. A fuel dispensing unit as claimed in any one of claims 1-6, characterised in that the leakage current causing system is arranged inside the fuel dispensing unit.

8. A fuel dispensing unit as claimed in any one of claims 1-7, characterised in that the leakage current causing system comprises a first electrical circuit (4) with a switch (7) and a resistor (8) which are connected in series between at least one phase conductor (P) and a protective earthing conductor (PE), and a second electrical circuit (9) with a switch (12) which is controlled by means of said sensor (3) and connected in series with a relay (13) arranged to close the switch (7) in the first circuit (4) when carrying current, the second circuit (9) being connected between a current source (11) and an earth conductor (10) arranged inside the fuel dispensing unit.

9. A fuel dispensing unit as claimed in claim 8,
characterised in that the fuel dispensing unit comprises a plurality of tamper/damage-detecting sensors, and the second electrical circuit (9) comprises a corresponding number of switches connected in parallel and controlled by means of said sensors.

10. A fuel dispensing unit as claimed in any one of claims 1-9, characterised in that the fuel dispensing unit comprises a voltage monitor (16) arranged to give a signal in case of power failure over the fuel dispensing unit.

Drawing