A device according to the preamble of claim 1 is known from EP-A-0,290,001 which, in Figure 1, shows an ice-cube tray with a mould cavity, which mould cavity is delimited on the underside by a piston body. A filling line, by means of which the mould cavity can be filled with water at the start of a freezing cycle, opens out at the top side of the mould cavity.

The ice-cube tray is connected to a freezing system which, once it has been switched on, freezes the water in the mould cavity. Then, the freezing system is briefly switched over to a heating system, with the result that the outer layer of ice will melt.

As a result of pressure then being exerted on the underside of the piston body via a pressure line, this body will move upwards and will push the ice cube upwards and out of the mould cavity.

After the pressure has been removed again, the piston body falls back to the bottom of the mould cavity under the force of gravity, after which the mould cavity can be filled again with water from above etc. in order for a subsequent freezing cycle to take place. In this known device, both the filling line and the pressure line are connected to the same water source or water pump. A switchable valve ensures that the flow of water, depending on the phase in which the freezing cycle is running, in one position is directed towards the filling line and in the other position is directed towards the pressure line.

A drawback of this known device is that a freezing cycle takes up a relatively long time. Considerable amounts of control engineering is required to ensure that the filling/freezing/releasing steps take place correctly during a freezing cycle. This makes the control means complex and the device expensive to produce. The water in the pressure line beneath the piston body is not refreshed or is scarcely

refreshed. It is therefore dead water which will be susceptible to deterioration. This contamination can easily pass to the filling line and consequently may lead to contaminated ice cubes.

The object of the present invention is to provide a device for the production of ice cubes in which these drawbacks are overcome. In particular, the invention aims to provide a simple and inexpensive device with which ice cubes can be produced quickly and efficiently.

According to the invention, this object is achieved by means of a device according to claim 1. The device comprises an ice-cube tray with a mould cavity in which there is an insert element which can move up and down. The insert element comprises a lifting part which, in a bottom position, forms a base part of the mould cavity and, during the upwards movement, can move an ice cube which has frozen in the mould cavity upwards with it.

The insert element is provided with a piston part, while the ice-cube tray is provided with a complementary cylinder part.

Furthermore, the ice-cube tray is provided with an inlet opening which is closed in the bottom position of the insert element and is opened during the upwards movement of the insert element.

Both the piston-cylinder system and the inlet opening are connected to water-metering means. The water-metering means can supply pressurized water and, for this purpose, if desired comprise a pressure pump which is connected to a water reservoir. Advantageously, the water pressure is used to move the insert element upwards during the release operation, while at any moment during the upwards movement of the insert element the inlet opening is opened automatically, so that the mould cavity is also filled with water for a subsequent freezing cycle. This filling of the mould cavity during the release operation saves considerable time. With this the design can be kept simple, since the inlet opening is opened automatically by the insert element moving upwards. Complex control means are not required. The filling line leading to the inlet opening can largely or completely share the pressure line leading to the piston-cylinder system. Consequently, dead water in the pressure line is avoided, and during each freezing cycle fresh water is flushed through substantially the entire pressure line.

Preferred embodiments of the invention are defined in the subclaims.

The invention will be explained in more detail with reference to the appended drawing, in which: Fig. 1 shows a diagrammatic, perspective view of a stand-alone apparatus with a device for the production of ice cubes according to the invention; Fig. 2 shows a cross-sectional view on line II-II from Fig. 1 in a freezing position, with the surrounding housing having been omitted; Fig. 3 shows a view corresponding to Fig. 2 in a release and filling position.

Fig. 1 shows an ice cube apparatus, with the apparatus partly cut away. The apparatus comprises a housing in which there is a dedicated water reservoir 1 and a device for the production of ice cubes, which is connected to the reservoir 1.

The device comprises a pump unit 2 which, via a filler tube 3, is connected to an ice-cube tray 5 with mould cavities 6. The ice-cube tray 5 is delimited on two sides by freezing elements 7, which in this case are formed by Peltier elements with cooling ribs 8. During operation, the cooling ribs 8 can be cooled as a result of cooling air being blown past the ribs via a fan 9. The air flow is discharged to the atmosphere via a grate in the surrounding housing.

Figs. 2 and 3 clearly show that the ice-cube tray 5 comprises an insert element 10 which can be moved up and down between a bottom position (Fig. 2) and a top position (Fig. 3).

The insert element 10 has lifting parts 11 which, in the bottom position, partly bear against the base of the mould cavity 6.

The ice-cube tray 5 is provided in its base with a cylinder part 12, which extends upwards into the mould cavities 6. The insert element 10 comprises a piston part 13 which extends downwards and is complementary to the cylinder part 12. The piston- cylinder system formed in this way is connected, by means of a connection piece 14, to the filler tube 3 of the pump unit 2. If the pump unit 2 is set in operation, the water pressure which is built up ensures that the piston part 13 is pushed upwards, together with the rest of the insert element 10, with respect to the cylinder part 12 and the ice-cube tray 5. With this the

upwards travel can be limited in various ways, for example by a stop pin which is fitted in the piston part 13 or by the top side of the insert element 10 coming into contact with a spring means or stop wall.

The cylinder part 12 is provided with two inlet openings 15 which, as a result of the insert element 10 moving upwards under water pressure, are opened automatically through a narrowing 19 in the piston part 13 coming to lie opposite the inlet openings 15. As soon as this takes place, water can flow into the mould cavities 6. After the pump unit 2 has been switched off, the water pressure will drop and the insert element 10 will move back into its bottom position, for example under the influence of a spring means or the force of gravity.

To accelerate the return movement to the bottom position, the insert element may be made heavier by means of a dead weight.

During the downwards movement, the thicker section of the piston part 13 once again comes to lie opposite the cylinder part 12 so that a seal is formed and the flow of water to the mould cavities is stopped again.

The inlet openings 15 are advantageously opened no earlier than close to the top position of the insert element 10 being reached. This ensures that the water pressure built up by the pump unit 10 is in the first instance utilized completely in order for the insert element 10 to be moved quickly upwards.

This is because as soon as the inlet openings 15 are opened, some of the water pressure will drop. Consequently, it is possible for a relatively low water pressure both to move the insert element upwards and to fill the mould cavities with water.

The device operates as follows: When a freezing cycle starts, the pump unit 2 is switched on. The insert element 10 moves upwards and brings the inlet openings 15 into flow connection with the water in the filler tube 3. The mould cavities 6 fill up with water. After a defined, set filling time, the pump unit is switched off. The insert element 10 moves back into its bottom position, and the freezing element 7 is switched into a freezing position. After a defined, set freezing time has elapsed, the freezing element 7 is switched off again. The water in the mould cavity 6 has then

frozen into ice cubes 20. The heat which is then still stored in the cooling ribs flows back to the ice-cube tray 10, with the result that the outer layers of ice of the ice cubes melt and the ice cubes rest freely inside the mould cavities 11. If Peltier elements are being used, it is even possible for the current direction to the thermoelectric elements to be reversed, so that these elements begin to actively emit heat on the side of the ice-cube tray 5. Then, the pump unit 2 is switched on again, as a result of which the insert element 10 will begin to move upwards again. In the process, the lifting parts 11 lift the ice cubes 20 which are formed up with them. In the highest position of the insert element 10, the ice cubes 20 are tipped over the sides of the ice-cube tray 5 and fall downwards. During the upwards movement of the insert element 10, the inlet openings 15 are also opened, and the mould cavities 6 are filled with water. The device is then ready for a subsequent freezing cycle. The combination of releasing the ice blocks 20 and filling the mould cavities 6 saves time and eliminates the need for a separate drive for moving the insert element 10 upwards and separate control for a filling line. Operating on the basis of ice cubes with a volume of approximately 8 cm3, the device has proven able to produce more than 30 ice cubes within a period of approximately one hour. The freezing time required for the production of a set of two ice cubes each with a volume of approximately 8 cm3 is less than ten minutes, and in particular only a few minutes.

In the variant shown, the insert element 10 has a vertical wall part 25 which, in the ice-cube tray 5, forms a partition between the mould cavities 6. The two lifting parts 11 extend on either side of the vertical wall part 25. The lifting parts 11 slope, making it easier to release the ice cubes in the highest position of the insert element 10. The operation of tipping the ice cubes over the sides of the ice-cube tray 5 during the release operation is further assisted by tipping elements 27 which are arranged above the ice-cube tray 5 and in this case are formed by curved leaf springs. During the upwards movement of the insert element 10, the ends of the tipping elements 27 come to lie between the vertical wall part 25 and the ice cubes 20, and thus the ice cubes 20 are pushed out over

opposite sides of the ice-cube tray 5. This is advantageous in particular because the assembly of ice-cube tray 5 and insert element 10 can be clamped between two freezing elements 7. The release direction is then directed between the two freezing elements 7.

Advantageously, it is possible to make the lifting parts 11 and the vertical wall 27 of any desired shape. This defines the final shape of the ice cubes, so that they can be given an attractive appearance. Since, moreover, the insert element 10 is easy to exchange, the ice cube apparatus can quickly and easily be adapted to a desired shape of ice cube, for example in the form of a hotel chain logo.

The freezing elements 7 are advantageously formed by peltier elements. If the peltier elements are connected to a DC voltage source, depending on the current direction heat will be extracted on one side of the Peltier element and an amount of heat will be emitted on the other side. The Peltier element can thus act as a heat pump which can be used to extract sufficient heat from the ice-cube tray 5 for the water in the mould cavities 6 to freeze and form ice cubes. Other types of freezing elements are also possible.

The apparatus may be provided with its own battery and/or may be provided with an electricity cable which can be plugged into a wall socket in order to supply in particular the pump unit and the freezing elements with current. In the apparatus, there are control means which comprise a timer unit for activating the various components of the apparatus in a defined order and for defined periods.

A residual-water outlet bin 30 is provided beneath the ice-cube tray 5. This outlet bin is used to collect the excess water which flows over the edge of the ice-cube tray 5 during filling. As a result, the filling time can advantageously be on the generous side, so that it is ensured at all times that the mould cavities 6 are given sufficient time to fill completely with water. The outlet bin 30, via a line 31, opens back out into the water reservoir 1 of the apparatus, so that the excess water can be reused during a subsequent freezing cycle.

Furthermore, beneath the ice-cube tray 5 there are guide chutes 34 which ensure that the released ice cubes 20 enter a

collection bin 35. The collection bin 35 is preferably large enough to accommodate a number of ice cubes which corresponds to a full water reservoir 1. The collection bin 35 is in this case designed as a slide-out drawer in order to allow the ice cubes to be taken out. The drawer may be provided in its base part with one or more leakage openings for allowing melt water to flow out. The leakage opening may open out above a leak bin (not shown) for collecting melt water. In the event of power failure, all the melt water which is released from ice cubes which have already been produced can then be collected.

;. The ice-cube tray 5 is preferably made from aluminium, which is a good thermal conductor. To further minimize the production time and the amount of energy required, the ice-cube tray 5 is designed to be as thin-walled as possible. In a particular embodiment, the walls of the ice-cube tray 5 and/or the insert element 10 may be coated with a layer of Teflon, so that the ice cubes are released from the mould cavities 6 more easily. The insert element may be made from either plastic or metal.

In addition to the embodiment shown, numerous variants are possible. For example, in one variant the filler tube may be directly connected, via a controllable valve, to a water supply system. The pressure pump is then surplus to requirements, since it is possible to utilize the pressure which is already present in the water supply system.

In another variant, the inlet opening is provided in a different part of the ice-cube tray, for example in the base. In this case, it is important for the insert element to comprise a closure element which is separate from its piston part for automatically opening and closing the inlet opening during the upwards and downwards movement, respectively. This closure element may, for example, be formed by a sealing pin which is connected to the underside of one of the lifting parts and, in the bottom position of the insert element, engages in a sealing manner in an inlet opening provided in the base of the ice-cube tray.

The insert element may also be designed without a vertical wall part, in which case it substantially comprises

only one lifting part and a piston part. The consequence of this is that only one ice cube is produced each time.

Thus, the invention provides a device which operates simply, quickly and efficiently. The device is of simple design, inexpensive to produce and hygienic to use. The various components interact virtually without making any noise and make it possible to construct a device of very small size. The use of mechanical components is limited, which increases the reliability of the apparatus and entails a minimum level of maintenance. Consequently, the device is eminently suitable for incorporation in a stand-alone ice cube apparatus for, for example, a home or a hotel room. The device may also be incorporated in other types of ice cube machines.