The present invention relates to a device for control¬ ling the switching-on and switching-off of consumer groups coupled in existing current distribution boards, or fuse boards, installed in electricity-consuming pre- mises, such as domestic buildings, said device including a cut-out element which replaces a conventional fuse in said current distribution board for a particular consum¬ er point or consumer group serviced by the board.

The need for electrical energy varies greatly with both large and small consumers of electricity, and the elec¬ trical energy which must be taken from the electrical power supply network in order to cover and satisfy this energy need at each and every moment also varies to a corresponding degree. Experience shows that electrical energy requirements are, under normal conditions, at their lowest during the nighttime, when many industries are shut down, and at their highest in the morning, when said industries start-up for the day. This uneven demand for electrical energy creates a large number of problems for the suppliers of electrical power, and not least the consumer peaks which occur normally in the morning when a large part of industry starts-up its operations, this variation costing large sums of money in comparison with the cost of a substantially constant energy outtake over each calendar day. Theoretically, these peaks can be greatly reduced by simply disconnect¬ ing, either completely or partially, consumer points or groups over those relatively short periods in which said peaks occur, for example such consumer points or groups as all domestic electrical immersion heaters, radiators,

water heaters, and other electrical appliances used for domestic heating and water heating purposes. If the power suppliers/electricity distributors were able to disconnect such consumer points or groups from the distribution network, or grid, the problem created by peaks in power consumption would be more or less solved. However, the distribution network and existing electri¬ cal energy supply installations are not constructed to enable existing consumer groups in present-day fuse boards or current distributing boards and module-con¬ structed domestic fuse boards and other consumer fuse boards to be controlled automatically in a manner which can be considered economically viable. It is possible that such control will be possible in the distant future.

One chain in the endeavours made to equalize the con¬ sumption of electrical power involves the introduction of differentiated electricity tariffs, with particularly low prices during those periods of the day in which the need for electrical energy is at its lowest, i.e. at nighttime, and therewith also the need to take energy from the distribution network, and thereby attempt to persuade consumers to use more electricity, at least for domestic heating purposes, during the low consumption periods over which lower prices apply. In order for this to be effective, however, it is necessary, in principle, for all consumers to be able to store energy during the low price periods and to use this self-stored energy during those periods when the need for electrical energy is at highest, and therewith also the cost in¬ volved. At present, this possibility is not available, however, and does not seem to be a likely possibility because of the expense involved.

At present, there is no real possibility for the indi¬ vidual consumer to effectively utilize the differentia¬ ted prices offered by the power distributors, and conse¬ quently one object of the present invention is to pro¬ vide the possibility for electricity consumers, both large and small, to utilize prevailing low price possi¬ bilities more effectively than has hitherto been the case, without needing to employ the services of a skilled person to this end.

This object is achieved with the inventive device which has the characteristic features set forth in the follow¬ ing Claims. In accordance with the invention, the cut¬ out element, or relay fuse, included in the inventive device is mounted within a casing and is connected by means of a phase conductor to an electrical contact element which is also mounted within the casing and which functions to break or make the phase conductor of said cut-out element in response to a control signal. Thus, the inventive device can be referred to as a relay fuse which is configured to fit into the socket fitting of the current distribution board, or fuse board, and which is just as simple to install on the fuse board as a conventional fuse.

The invention will now be described in more detail with reference to the accompanying drawings, in which Figure 1 is a schematic, sectional view of an inventive relay fuse; Figure 2 is an end view of the relay fuse shown in Figure 1; Figure 3 is a sectional view similar to the view of Figure 1 and shows an alternative embodi¬ ment of an inventive relay fuse, and Figure 4 is a schematic front view of a conventional current distribu¬ tion board in which inventive relay fuses can be used instead of conventional fuses.

As before mentioned, the inventive device may be re¬ ferred to as a relay fuse and is constructed in a manner which enables it to be used in a distribution board A (Figure 3) of an electricity consumer for the purpose of controlling the switching-on and switching-off of a two- phase or three-phase consumer point B and/or a consumer group in the distribution board A concerned. Thus, the inventive cut-out relay fuse, generally referenced C, replaces in the distribution board a standard fuse element D which serves the particular consumer point or consumer group intended.

The inventive relay fuse C is housed in a fuse holder 1 made of non-conductive material, such as bakelite, ceramic, rubber, or plastic material, said fuse holder 1 having mounted on one end wall thereof a fitting 2 made of electrically-conductive material. The illustrated embodiment of the inventive relay fuse is intended for use in distribution boards that are constructed for screw-threaded fuse elements D, and the fitting provided at said one end of the fuse holder comprises a sleeve 2 which is made of an electrically-conductive material and has an external screwthread 3 which corresponds to the screwthread of the fuse socket in the distribution board concerned. When the distribution board to which the inventive relay fuse is to be fitted has a different fuse fitting, the fitting 2 of the inventive device may, of course, be given a corresponding configuration.

Firmly mounted within the fuse holder 1 is a fuse seat 4, the electrically-conductive contact plate 5 of which is connected electrically to an externally insulated, preferably rod-shaped conductor 6 which projects out concentrically from the fuse holder 1 and extends con- centrically through the screw-threaded sleeve-like fitting 2 and which presents at one end an electrical

contact element 7 for contact coaction with a fitted electrical contact or fuse adapter 8 on a phase bar 9 included in the distribution board A. The electrical contact element 7 present on the end of the conductor 6 shall have a largest diameter or width which is smaller than ^" the smallest gap width of the fitted electrical contacts 8 provided, such that the contact element 7 of the inventive relay fuse will fit all occurring fitted contacts 8.

Carried in a known manner in the fuse seat 4 is a known fuse 10 which is held in place and in electrically conductive contact with the contact plate 5 of the fuse seat 4 by means of a sleeve-like carrier which can be secured to the other end side 11 of the holder and which when fastened in the holder wall 11, e.g. by means of a bayonet, screw or snap-on fitting, connects the fuse 10 electrically with an electrical contact element 14 provided within the holder 1 through the medium of its electrically conductive sleeve-shaped inner part 13. In turn, the element 14 is connected to the sleeve 2 of the relay fuse, this sleeve functioning as a phase conductor via a phase conductor 15 provided within the fuse holder 1.

In accordance with the present invention, a contact element or relay contact 16 is connected in the phase conductor 15 and functions to connect and disconnect the phase conductor circuit. This relay contact 16 includes a moveable contact element 17 and two stationary contact elements 17 in the phase conductor 15. When the move- able contact element 18 is in the position shown in Figure 1, i.e. the circuit breaking position, the phase conductor 15 is thus broken and no current will be allowed to pass. When the moveable contact element 17 is moved into contact with the two stationary contact

elements 18, i.e. in the circuit making position, the phase conductor 15 is closed and current is allowed to pass through the relay fuse from the phase bar 9 of the distribution board to the fitting 2 and from there to the consumer point.

The moveable contact element 17 of the relay contact 16 is connected to switching device 20 by means of which said moveable contact element can be switched either to its circuit making or its circuit breaking position.

The switching unit 20 may be either mechanical, electro¬ mechanical or electronic within the scope of the present invention, without departing from the inventive concept. In this case of the embodiment illustrated in Figure 1, the switching unit 20 has the form of an electromagnet 21 having a coil 22 which is connected to the phase conductor 15 on the fuse side, via a neutral conductor 23, to a connecting terminal, connecting screw or some other connecting device 24 which is firmly mounted on the outer surface of the casing, preferably on its end wall 11. Connected to the connecting device 24 is a pilot conductor 25 which functions as a zero conductor and which extends from a control unit 26, for instance a time clock which functions to deliver a control signal to the unit 20, i.e. the electromagnetic 21 in the case of the Figure 1 embodiment, causing the contact relay 16 of the inventive relay fuse to be switched on or off.

Figure 3 illustrates an embodiment in which the contact unit 20 for controlling the electrical contact element 16 is an electronic structure in the form of a circuit board or circuit card 27 which incorporates the function of said contact element 16.

According to the present invention, the pilot conductor 25 connected to the connecting device 24 is a so-called

zero or neutral conductor and consequently the load from the switching unit 20 is negligible, irrespective of whether said unit is electromagnetic or electronic, thereby enabling the use of so-called icrocontacts or mini contacts as connecting devices, as illustrated at 24 in Figure 3, for connection of the intended control unit 26.

As illustrated in broken lines, the switching unit 20 of the embodiments illustrated in Figures 1-3 is fused with the aid of a control fuse 28 mounted in a fuse carrier 29 of the same kind as that used for the main fuse 10 of the relay fuse. The fuse carrier 29 is connected to the electrical contact plate 14 by means of a conductor 30 and, through the control fuse 28, via a conductor 31 to the contact point 18 of the electrical contact element connected to the phase conductor connection from the control fuse 28. As illustrated in Figure 2, the inven¬ tive relay fuse or cut-out element may also be provided with a manual on-off-switch 32, which is preferably connected upstream of the switching unit 20.

Figure 4 illustrates a conventional distribution board A which controls, for instance, the electrical consumption of a homeowner using electric immersion heaters for water-carried heat and hotwater heaters. These three- phase consumer points B are protected by conventional fuses D in the distribution board A. The times at which these consumer points are switched on and off, and also the times at which other consumer points connected to the distribution board A are switched on and off can be controlled by replacing respective conventional fuses with an inventive relay fuse C.

The inventive relay fuse C according to Figure 1 is screwed into the distribution board A in the same manner

as a conventional fuse, and since this can be achieved by any one whomsoever, there is no need to employ the services of a skilled person. This represents a consid¬ erable cost-saving on the part of the consumer, since no authorized person is required to install the inventive relay fuse. With the inventive relay fuse installed, each consumer is able to connect the current supply to a selected consumer point during the low price periods, for instance during the night, and to interrupt this supply during the high price periods automatically, for instance with a control unit in the form of a time clock.

When relay cut-out devices according to the present invention are fitted, the suppliers of electricity can cut consumption peaks in an effective and inexpensive manner, by disconnecting certain consumer groups, such as water heaters, direct-acting electrical elements, electrical immersion heaters for water-carried heat and the like during those short periods in which consumption peaks occur, with the aid of so-called all-round control systems.

The invention is not restricted to the aforedescribed and illustrated embodiments thereof, since modifications and changes are be made within the scope of the follow¬ ing Claims.