Safety device for dishwashers and washing machines

Abstract

 A safety device in particular for dishwashers/washing machines, characterised by comprising at least one metal element (2) disposed within a tray (4) positioned below the frame of the dishwasher/washing machine, said metal element being electrically connected to a low voltage terminal (8) of a microprocessor (10), and a second metal mass facing said metal element (2) such as to provide a substantially infinite resistance when water is absent from the tray, but to provide a non-infinite resistance if water deposits in the tray, such that the microprocessor (10) halts the operating cycle of the dishwasher/washing machine.

Description

[0001] The present invention relates to a safety device in particular for dishwashers and washing machines.

[0002] Safety devices are known for protection against water leakage in dishwashers.

[0003] These known devices consist substantially of an expanded polystyrene float inserted into a container provided on the bottom of a metal basin positioned below the dishwasher frame.

[0004] If water leaks from the dishwasher, the water level raises the float, to activate a microswitch which interrupts the electrical power circuit of the dishwasher, hence halting its wash cycle

[0005] However these known devices have the drawback not only of a high cost but also of not being able to be used in a washing machine because of the considerable vibration generated during spinning, which could cause the float to falsely intervene.

[0006] The object of the invention is to eliminate this drawback by providing a safety device against water leakage which intervenes reliably and safely.

[0007] This drawback is eliminated by a safety device particularly for dishwashers/washing machines as described in claim 1.

[0008] The present invention is further clarified hereinafter with reference to the accompanying drawings, in which:

Figure 1 is a schematic view of a first embodiment of the safety device, and

Figure 2 shows a second embodiment thereof.

[0009] As can be seen from the figures, the safety device of the invention consists, in the embodiment shown in Figure 1, of a metal pin 2 which is maintained electrically isolated from a metal tray 4 positioned below the frame of a washing machine 6 to collect any water which leaks from it.

[0010] The pin 2 is connected electrically to a low voltage terminal 8 also used for feeding a microprocessor 10 which controls, inter alia, the power circuit of the washing machine.

[0011] The device of the invention operates as follows:

When the washing machine is operating normally, the microprocessor 10 receives a signal of infinite resistance between the pin 2 and the metal tray 4.

When water leaking from the washing machine deposits on the bottom of the tray 4, the presence of water between the pin 2 and the metal tray creates a non-infinite resistance, the microprocessor 10 receives a signal that an abnormality has arisen, the microprocessor consequently intervening to interrupt mains power and halt the wash cycle.

[0012] In the embodiment shown in Figure 2, the tray is of plastic material, in its base there being provided two metal pins 2, 2' which are insulated from each other and are connected respectively to a terminal 8 of the microprocessor 10 and to the washing machine earth. Again in this case, water deposition in the tray results in a resistance reduction, with intervention of the microprocessor to interrupt the power feed.

[0013] From the aforegoing it is apparent that the safety device of the invention presents the advantage of intervening in a reliable and safe manner, within the framework of a very simple construction.

Claims

1. A safety device in particular for dishwashers/washing machines, characterised by comprising at least one metal element (2) disposed within a tray (4) positioned below the frame of the dishwasher/washing machine, said metal element being electrically connected to a low voltage terminal (8) of a microprocessor 10, and a second metal mass facing said metal element (2) such as to provide an infinite resistance when water is absent from the tray, but to provide a non-infinite resistance if water deposits in the tray, such that the microprocessor halts the operating cycle of the dishwasher/washing machine.

2. A device as claimed in claim 1, characterised in that said second metal mass is the tray itself.

3. A device as claimed in claim 1, characterised in that the tray is constructed of plastic material, the second mass being connected to the dishwasher/washing machine earth.

Drawing