The invention relates to an actuator system comprising at least one cabinet, a least one electrically driven linear actuator with an electric motor, a transmission, a spindle connected to the electric motor through the transmission, on which spindle a spindle nut is mounted, and an electrical controller with an operating unit. Actuator systems with electrically driven linear actuators are widely used within the field of adjustable furniture, such as for example adjustable tables, adjustable beds and chairs. Electrically driven linear actuators are also used in numerous other industrial products, wherein an electrically driven linear actuator is advantageously integrated into a mechanical structure for the adjustment of a mechanically movable component. Linear actuators comprising a piston rod, for example of the type described in WO 02/29284 Al to Linak A/S, are highly suited to the task. Linear actuators may also be designed as lifting columns, as described in WO 2004/100632 Al to Linak A/S. Linear actuators may also be designed as dual actuators, cf. for example WO 2007/112745 Al to Linak A/S.

The actuator system is usually powered by mains via a converter adapted to convert the alternating voltage from mains to a direct voltage at a suitable voltage level. In case of failure of mains, or if the actuator system is integrated into a mobile system which cannot be connected to the mains continuously, the actuator system may be powered by an alternative voltage supply, such as e.g. a battery. The battery may be of a chargeable type in which case it is charged when the actuator system is connected to mains, or by alternative energy sources such as e.g. solar cells. The battery may also be of a primary cell non-chargeable type. For example used as a security backup, wherein the battery is only used in an emergency situation, after which it must be replaced.

A controller for an actuator system exists, which facilitates connection of different power sources, but the manufacturing costs are high. In many cases it will be sufficient for the controller to be connected to mains, for which reason the extra, non-utilized connection possibilities only cause unnecessary costs for the manufacturer and ultimately for the customer.

Another challenge is the trend toward applications utilizing electrical actuator systems increasingly being used for controlling more and more actuators, which may be driven either together or separately. With the use of electrical actuators designed as adjustable columns in connected height-adjustable kitchen elements, there may for example be an adjustable column in each individual kitchen element. In order to solve the problem, a plurality of actuator systems each having its own individual controller must be installed and connected into an inter-connected system. There may obviously be great differences as to what is stored in the various kitchen elements, for which reason some of the actuators will be subjected to greater loads than others and therefore require a larger power supply in order to handle the load. This problem can be solved by selecting a stronger power supply, particularly for connection to the controller and the actuator under load. However, it is difficult to decide in advance whether there is a need for more power, and if so, which column or columns will require more power. A stronger power supply is more expensive, which would make it a price-raising and perhaps unnecessary procurement of equipment to fit all ^' columns with this type of power supply.

Thus, a solution to the outlined problem is required, which arises when actuator systems with a plurality of controllers and a plurality of actuators are unevenly loaded and each of which require electrical power of a different magnitude for them to be able to cooperate in performing a task, for example adjusting the height of a piece of furniture.

Moreover, an easier way of connecting an alternative power source is desirable, for example a battery supply. This is achieved according to the invention by designing the actuator as indicated in claim 1, wherein the controller is fitted with at least one further interface, from which second interface the regulated supply voltage of the controller is available.

The controller may be powered from a primary power supply connected to mains. This generates a regulated supply voltage which is used in the controller. During operation, depending on the power of the power supply there will be either an excess or a shortage of electrical energy available to the system at hand. The extra interface, at which the regulated supply voltage of the controller is available, makes it possible to exchange electrical energy with other, parallel actuator systems. In practice this can be done by providing the actuator system with a power outlet, for example a socket with a plug connection, where the regulated supply voltage can be drawn. More specifically, the power outlet may be freely positioned on the controller cabinet or on the cabinet of a linear actuator or on the cabinet of another piece of equipment fitted to be connected to the actuator system. Understood in the widest sense, the aim of the invention is thus to make the regulated supply voltage of a local actuator system available outside the actuator system. In its most simple design, the interface where the regulated supply voltage of the controller is available is led out of the controller as a cable connection with a ready-to-use plug connection.

The controller may be powered from a primary power supply connected to mains. From here a regulated supply voltage is generated that is used in the controller. During operation, depending on the power of the power supply there will be either an excess or a shortage of electrical power available to the system at hand. The extra interface, at which the regulated supply voltage of the controller is available, makes it possible to exchange electrical energy with other, parallel actuator systems .

This exchange of electrical energy with parallel actuator systems is performed via a bus connection for powering the actuator system in the form of a cable with at least two electrical conductors, which is adapted for establishing a connection between the at least one interface on a first actuator system and the at least one interface on a second actuator system, from which interfaces the regulated supply voltage from the controllers in the actuator systems is available.

By connecting the regulated voltage supply on the actuator systems by means of the bus connection, electrical energy can successfully been transferred from one actuator system to another and vice versa. If the load on one of the systems is greater than that on the other, the said system is able to utilize the extra power available via the bus connection. The bus connection also provides the opportunity for an actuator system to be without a primary power supply and indirectly draw on the power supply of a parallel actuator system. Thus, a simpler system structure is achieved, as only one power supply connected to mains is necessary, which if necessary could be more powerful.

In one embodiment, the controller is adapted to be able to activate or interrupt the connection between the internal supply voltage of the controller and the at least one interface. This ensures that the controller is able to function independently if the bus connection short-circuits. In the simplest design, this could be achieved by means of a fuse, but more advanced and resettable solutions are envisaged such as e.g. automatic fuses, a relay or a transistor-based switch operation.

The controller is thus adapted to be able to supply or receive electrical power by allowing an electrical current to be conducted via the at least one interface, wherein the regulated supply voltage of the controller is available, by which means the bus connection can meet the requirement for electrical power between the actuator systems connected on the bus.

Supplying electrical power according to requirement for an actuator system connected to the bus connection is undertaken in that the controller is adapted to interrupt a supply of current from the at least one interface, where the regulated supply voltage of the controller is available, in case the voltage level on the bus connection is higher than the voltage level applied to the controller from a connected primary supply. Instead it will be possible for the controller to draw a current from the bus connection. If the primary supply voltage is e.g. under load, the voltage level will drop, and if the voltage level on the bus connection is higher, the current will supply the controller from the bus connection and thereby contribute to supplying an actuator under load with extra electrical power.

Accordingly, the controller is adapted to interrupt or limit a supply of current from a connected local primary supply, if the voltage level on the bus connection is higher than the connected primary supply. If the primary power supply of the actuator system is a chargeable battery pack or a primary cell, intended for emergency operation, it is not desirable to discharge these, in cases where a more stable supply voltage exists, such as a power supply connected to mains. The said power supply may be physically connected to a parallel actuator system and can, with the invention, effectively supply its electrical power to other actuator systems via the bus connection. If the system is adapted therefor, the chargeable battery pack may be recharged with electrical power supplied via the bus connection. Here, it will be advantageous for the controller to have means for limiting the charging current such that the bus connection is not loaded and prevented from supplying the necessary electrical power when the actuator system is operated. Alternatively, recharging of the battery may be interrupted briefly when the actuator system is being operated.

In an embodiment, the actuator system comprises a chargeable battery pack which is adapted to be connected directly on the bus connection or to the actuator system via the at least one interface, wherein the regulated supply voltage of the controller is available. Thus, a simple connection to the actuator system is achieved also in case of a single actuator system without a bus connection for distribution of the electrical power to other actuator systems according to the invention.

The battery pack may furthermore be provided with a power supply for connection to mains and/or a charging circuit, ensuring that recharging of the battery pack is done safely.

In an embodiment relating to the design and dimensions of different types of power supplies, which is adapted to be connected to the actuator system, a power supply is. dimensioned in such a way that the level on the output voltage of one primary mains-connected power supply is higher than the output voltage of a chargeable battery pack, which in turn is higher than the output voltage on a primary battery pack. Thus, it is easy to ensure that the mains-connected power supply if present on the bus connection, powers the system rather than chargeable or primary battery packs. This still has the advantage that in case the mains-connected power supply is loaded such that the output voltage drops to the voltage level of e.g. a chargeable battery pack, the battery pack will temporarily be able to supply a current and ensure that the system is functioning despite the increased load. Thus, even with a system in which the mains-connected power supply is in some cases under-dimensioned, it is still possible for the actuator system to supply the required momentum. Even though the supply from the chargeable battery pack is temporarily drained, this electrical charge can rapidly be recharged when the actuator system is not operated. Battery packs are most often used in mobile actuator systems such as, e.g. mobile beds, which from time to time need to be moved and during this period of time are prevented from being connected to mains. Chargeable battery packs can also be used as energy storage for alternative energy generators such as solar cells, and by using the bus connection this energy resource may be used effectively if the energy generator is adapted to connect its electrical power directly to the bus connection. Thus, the energy will be able to charge the chargeable battery packs connected thereto. The bus connection also enables the use of alternative energy generators placed outside the actuator system. Solar cells may e.g. be placed in a window section and still be connected to the bus connection. In yet another embodiment, the controller is adapted to measure the voltage level at the at least one interface, wherein the regulated supply voltage of the controller is available and/or the bus connection and/or its own regulated power supply and depending on the voltage level be adapted to adjust the controller to various energy- saving modes, reflecting the available power of the bus connection. Without going into detail, it may be permissible to be more generous with the electrical energy available, when the power supply is connected to mains. For example, it may be desirable to have illuminated operating panels, or perhaps a night light is turned on as lighting under the bed for orienting oneself in the dark. This deliberate choice and desire is acceptable as long as a power supply is connected to mains. However, continuous power consumption is associated with a major disadvantage in case of a battery driven system, and should to the extent possible be avoided in order to ensure that the actuator system can continue to be operated. The energy-saving modes can suitably be activated after an interval of time has elapsed since the last operation of the actuator system.

In an embodiment, the controller is adapted to interpret and process a connected piece of equipment which applies a voltage to the at least one interface, as a potential power supply, which fully or partly will be able to supply the actuator system with power.

A linear actuator system according to the invention will be described in greater detail in the following with reference to the accompanying drawing, in which:

Fig. 1 shows a kitchen arrangement consisting of five joined kitchen elements with wall cupboard,

Fig. 2 shows a kitchen arrangement provided with actuator systems with a total of four columns for height adjustment of a piece of joined kitchen furniture,

Fig. 3 shows a schematic view of the actuator system shown in Fig. 2,

Fig. 4 shows a principal sketch of a system having three controllers e.g. for use in a piece of height- adjustable kitchen furniture,

Fig. 5 shows a graph of the distribution of supplied electrical power from the connected power supplies for a piece of height-adjustable kitchen furniture,

Fig. 6 shows an adjustable bed having two columns and two actuators for adjusting a back rest and leg rest section, Fig. 7 shows a schematic view of the actuator system incorporated into the bed in Fig. 6,

Fig. 8 shows a height-adjustable table comprising an actuator system,

Fig. 9 shows a schematic view of an actuator system, incorporated in a wheeled table,

Fig. 10 shows a schematic view of an actuator system adapted for use in adjusting the resting surface of an adjustable bed,

Fig. 11 shows a schematic view of an actuator system specifically adapted for a bed,

Fig. 12 shows a schematic view of an actuator system specifically adapted for a bed with a primary battery intended for emergency lowering connected to the DC bus,

Fig. 13 shows a schematic view of an actuator system specifically adapted for a double bed,

Fig. 14 shows a schematic view of an alternative actuator system specifically adapted for a double bed,

Fig. 15 shows a schematic view of an actuator system specifically adapted for use in a treatment chair, and

Fig. 16 shows a schematic view of an actuator system specifically adapted for use in a reclining chair.

Fig. 1 of the drawings shows a kitchen arrangement 1 consisting of a base unit 2 and an top unit 3. The base unit 2 consists of five joined kitchen elements. As shown in Fig. 2, the base unit 2 of the kitchen arrangement 1 is provided with two actuator systems, each consisting of a controller 4, 7 and two columns 5,6,8,9, each of which comprises at least one electrical linear actuator. The actuator systems are provided with a communications bus which ensures that both actuator systems may be operated by a common operating unit 10 and can be driven in parallel. By this means, the joined base unit 2 can be raised and lowered as a unit. It is a given that the load on each individual actuator 5,6,8,9 in the actuator system can vary. Although the load on a joined kitchen element will be distributed due to the mechanical joining, an uneven load may occur, e.g. in case one of the outermost cupboards is heavier. It may for example be that the cupboard is full of tinned goods or tableware, or a heavy piece of kitchen equipment may have been placed on the tabletop. When the two actuator systems are independently powered, the problem may arise that the power supply for one of the actuator systems is not capable of supplying the necessary power for the actuator, which can result in slow adjustment or distortion of the kitchen unit. According to the invention this can be compensated for by interconnecting the regulated power supplies of the two actuator systems, by which means the electrical power available is distributed between the actuators as required and thus facilitating a more flexible and efficient system. In order to ensure extra power for peak loads and in case of an emergency, a chargeable battery pack 11 has also been incorporated into the kitchen unit. Shown here is a joined kitchen element with a fixed position in a kitchen. The chargeable battery pack 11 will be even more useful when used in a height-adjustable mobile kitchen island which can be used for different layouts of the same kitchen environment.

Construction of the actuator system for the kitchen arrangement shown in Figs. 1 and 2 is moreover shown in Fig. 3, which shows the two controllers 4, 7 each with its own incorporated power supply intended for connection to mains. The four actuators 5,6,8,9 are connected in pairs to a controller 4,7 each. The operating unit 10 is only connected to one of the controllers 7, but controls both actuator systems as a result of the coupling on a communications bus 12. The regulated supply voltage in the two actuator systems are interconnected by means of the bus connection 13 for interconnecting the regulated supply voltage of the controllers, hereinafter referred to as the DC-bus 13. A chargeable battery pack 11 is also connected to the DC-bus 13. The battery pack 11 contains its own charging circuit 14, which is adapted to draw power from the DC-bus 13 when excess power is available for charging the battery pack 11. The battery pack 11 can furthermore be furnished with its own mains-connected power supply, which may be adapted to supply a regulated voltage to the DC-bus 13, when this is not charging the battery 11. The battery pack 11 can furthermore be provided with a converter, which converts the voltage level on the batteries in the battery pack 11 to a level closer to the voltage level of the DC-bus 13. If the battery pack 11 e.g. is a 12V (twelve volts) lead battery, it will be necessary to make provisions for a step up by using a switch mode converter of the boost type. The use of the DC-bus 13 generally also has the advantage that a system is more reliable and fail-safe, in that the actuator system can continue to be used even if a single or a plurality of the total number of power supplies or chargeable battery 13 in the system fails or are interrupted.

Fig. 4 is a principal sketch showing three controllers 15, 16, 17 for actuator systems. The actuator systems can be used in kitchen arrangements 2 as referred to under Figs. 1 to 3, but can also be used for many other applications. The controllers 15, 16, 17 are adapted each with its own power supply 18, 19, 20, which has the possibility of connection to mains. As such the controllers may be considered as independent units both in respect to control of the connected actuators and any other eguipment as well as in relation to the power supply of the controller 15, 16, 17 and the equipment connected to the controller (electrical actuators etc.). With the bus connection for interconnection of the regulated supply voltage of the controllers, hereinafter referred to as DC-bus 21, a connection is established between the three controllers 15, 16, 17, such that the total electrical power available can be distributed between the mutually interconnected controllers 15, 16, 17.

The columns that are adapted to perform a lifting/lowering function of a joined kitchen furniture section 2 are, in the example, subjected to an uneven load, for which reason the power consumption of the columns during operation, results in the powers PI, P2, P3. This power is stated as the power the column would use if the potential supplied power from the connected power supply 18, 19, 20 was unlimited. As a hypothetical example intended to explain the advantages of the system according to the invention, the power supplied by the connected power supplies 18, 19, 20 are different and are named PS1, PS2, PS3. The values are selected in such a manner that some of the power supplies 18, 19, 20 cannot supply the necessary power to the actuator system in which they are physically positioned. The power supplies

18, 19, 20 are constructed such that their output voltage varies with the load in accordance with the "soft knee" principle. The output voltage will therefore drop when the load is increased. All power supplies 18, 19, 20 are designed in such a way that at maximum load they will have the same defined nominal output voltage. This means that when connected to the DC-bus 21, power supplies 18,

19, 20 with excess power have a higher voltage level and are thereby able to compensate for power deficiencies in systems with power supplies 18, 19, 20, that are loaded to the maximum load.

Fig. 5 is a graph showing the voltage level of the power supplies 18, 19, 20 relative to the load. To be more specific, the lines 22, 23, 24 each describe the voltage level of each power supply 18, 19, 20, if said power supply were local and not connected to the DC-bus 21. As can be seen, the voltage drops when the requirement for electrical power increases. The maximum power of the power supply is reached when the line goes beneath the horizontal line describing a nominal voltage Vn. If the power on the power supplies in a hypothetical example PS1 of 175W, PS2 of 160W and PS3 of 150W in a scenario wherein the power consumption is PI of 200W, P2 of 200 and P3 of 85W, respectively, it will thus be possible to interconnect the three power supplies PS1, PS2, PS3 into a combined PST of 485W which will be able to drive PI, P2 and P3 with a combined power total PT of 485W. The DC-bus 21 will distribute the electrical power within the system, such that no section of the system will be starved of power. It is, however, on the condition that there is sufficient excess electrical power available in the system. In a system with three separately constructed and isolated actuator systems overload of one of the systems would be a hindrance to the overall movement of the entire system, which e.g. would result in a slow height adjustment of a joined piece of kitchen furniture, the DC-bus 21 with the distribution of an excess available electrical power will cause the system as a whole to react more promptly. By using chargeable battery packs 11, a power consumption higher than recommended from mains-connected power supply can be temporarily or long-term supplied. The duration is of course dependent upon the capacity of the battery. To avoid discharging of the battery 11, the nominal output voltage of the battery must be lower than the nominal output voltage Vn of a mains-connected power supply. In order to ensure that the chargeable battery 11 is not charged in situations where the mains-connected power supply 18, 19, 20 must produce its maximum power in order to supply the actuator system, there can expediently be an in-built hysteresis between the voltage levels, where the battery 11 supplies a current and is supplied with a charging current, such that the battery 11 is only charged when the mains-connected power supply 18, 19, 20 is relatively unloaded.

Differentiation of the dimensions of a mains-connected power supply 18, 19, 20 and the nominal voltage level of a chargeable battery pack, also results in the controller 15, 16, 17 being able to, depending on the voltage, enter into various current-energy-saving modes according to the electrical power available. For example, if the supply voltage is so low that the controller 15, 16, 17 will assume that the power is supplied by a chargeable battery 11, it will make sense to enter into an energy-saving mode in which unnecessary power consumption for example for lamps, is prevented or minimized. Particularly in case of operation from a primary battery it is desirable to have the lowest possible power consumption, if not zero consumption, when the actuator system is not in operation. In this case the voltage level of the primary cell will e.g. indicate to the controller 15, 16, 17, that the only available function is an emergency lowering of the system in connection with an emergency situation. This function is particularly intended for beds in which it, in case of an emergency, is desirable to be able to lower a head section and leg rest section into a Trendelenburg position, regardless of whether the controller 15, 16, 17 is being supplied with power or not. It will be desirable for the controller 15, 16, 17 also to be provided with an indicator, which shows when the primary battery is discharged and should be replaced. In a specific embodiment, the primary cell may consist of one or more 9V (nine volts) standard alkaline batteries in a battery casing for that purpose, which may be connected to the controller 15, 16, 17 via a cable with a plug connection.

An application of an actuator system as used in a hospital bed or care bed is shown in Fig. 6, where a hospital bed 25 comprising a subframe 27 is provided with drive wheels 26, and an upper frame 28. An adjustable supporting surface 29 for a mattress (not shown) is mounted on the upper frame 28. The supporting surface comprises a back rest section 30, an articulated leg rest section 31 and a fixed central section 32 between the two. The back and leg rest sections 30, 31 can each be adjusted with its own actuator 33, 34, such that the supporting surface can adopt differing contours. The upper frame 28 is coupled to the subframe 27 with two linear actuators designed as lifting columns 35, 36 at each end. The upper frame 28 may be raised and lowered by activating the lifting columns 35, 36. The actuators 33,34,35,36 are connected in pairs to a controller 37, 38. More specifically, the actuators 33, 34 are connected to the controller 37 and the actuators 35, 36 are connected to the controller 38. The controllers 37, 38 may be connected to mains and may, for example, be provided with a power supply. The actuator system also comprises a rechargeable battery pack 39. Within the controller there is furthermore the possibility for connecting one or more operating units, such as a hand control 40 and an operating panel 41 integrated into the end board of the bed, as well as possibly other peripheral equipment. The system as a whole, comprising actuators 33,34,35,36, controllers 37,38 and operating units 40,41 is called an actuator system. Please also note the under bed light 42 mounted on the upper frame of the bed.

Fig. 7 is a schematic view of the actuator system incorporated into the bed in Fig. 6. Reference is made to the description of the bed under Fig. 6. The schematic view also reveals that the two controllers 37, 38 are connected to a communications bus 43, such that both controllers 37, 38 can be operated from the same hand control 40. The schematic view also shows the DC-bus 44 which connects the regulated supply voltage of the two controllers. As can be seen, the chargeable battery pack 39 is also connected to the DC-bus 44.

Fig. 8 shows a height-adjustable table 45 comprising an actuator system. The height-adjustable table 45 comprises a tabletop 46. At each side of the height-adjustable table 45 there is a linear actuator in the form of a lifting column 47 mounted within a supporting frame to which the tabletop 46 is secured. The other end of the lifting column 47 comprises a foot 48. Here the actuator system brings about an adjustment of the tabletop 46, for example a height adjustment.

A plurality of height-adjustable tables may be put together to make up a conference table (in the same way as kitchen elements are joined together) thus enabling the interconnection of the regulated voltage supply of the controllers via the DC-bus with the advantages outlined above.

Furthermore, Fig. 9 shows a schematic view of the actuator system, where the system is incorporated into a wheeled table 49. During operation of the operating panel 50, a height adjustment of the tabletop 51 may be undertaken. The height adjustment is performed by an electrical linear actuator in the form of a lifting column 52. The controller 53 is equipped with a power supply 54, which may be connected to mains. If the wheeled table 49 is not within the vicinity of a power socket, the controller 53 is supplied by the battery pack 55. The battery pack 55 is mounted under the tabletop 51 and is connected to the DC-bus 56, which is also connected to the controller 53. Thus, the controller 53 can automatically be supplied from mains if this is available and from the battery pack 55 if the mains connection is interrupted. The battery pack 55 is provided with a charging circuit and charged by a supply from the DC-bus 56.

Fig. 10 shows a schematic view of an actuator system for adjusting the lying surface of an adjustable bed. The adjustment may be performed by operating the wireless operating unit 57. The power supply 59 of the controller 58 is primarily mains-connected. Focusing on the DC bus 60, a primary cell 61 is connected, and can in an emergency situation supply electrical power for lowering the adjustable sections of the bed. The voltage level is so low that the controller cannot raise the lying surface contour. Depending on the configuration, it will not be possible to use a wireless operation unit. Lowering may alternatively be undertaken by operating a button at an accessible position, for example on the controller 58.

The schematic view shown in Fig. 11 likewise shows an actuator system specifically adapted for a bed. The dual actuator 62 is adapted to adjust a back and leg rest section in an adjustable bed and is furthermore provided with three single actuators 63,64,65 which are also controlled and supplied from the in-built controller incorporated into the dual actuator 62. The dual actuator 62 is supplied from mains via an adapter 66. Operation of the actuator system is performed by means of a wireless operating unit 67, wherein the receiver is integrated with the controller in the dual actuator 62. The system further comprises a controller 68 which is adapted to drive two massage motors 69,70 and two power outlets 71,72 with USB sockets. The controller 68 is connected to the controller of the dual actuator 62 by reciprocal connection to a communications bus 73, enabling operation by means of the same operating unit 67. Furthermore, both controllers are connected to the DC-bus 74, which enables the controller 68 to be supplied with electrical power from the dual actuator 62.

Fig. 12 shows, as a supplement to Fig. 11, a primary cell connected to the DC-bus 74 for emergency lowering. Fig. 13 is a schematic view showing an actuator system specifically adapted for a double bed. The dual actuators 76, 77 adjust the lying surface of each bed, and the actuators 78,79, designed as columns, are intended for adjusting the height of the bed frame. The power supply 80 of the system is incorporated into the controller 81 for the columns and is connected to the dual actuators via the DC-bus 82. The DC bus 82 thus ensures a low-cost construction with one power supply 80 which powers the entire actuator system. The actuator system ^■ can be operated by means of the two shown wireless hand controls 83, 84. The communication between the three interconnected units is performed via the communications bus 85.

Fig. 14 is a schematic view showing an alternative actuator system specifically adapted for a double bed. The operation is undertaken with two wireless hand controls 86, 87, and the receiver 88 is connected to the controller. The actuators for adjustment of the lying surfaces 89 of the beds are constituted by the four discrete actuators 90,91,92,93. All four actuators 90,91,92,93 are connected to the controller 94, which comprises an in-built power supply 95 connected to mains. A primary cell 96 is connected via the DC-bus 97 to the controller 94 and is able to supply electrical power for adjusting the actuators 90,91,92,93 downwards in the event of an emergency, in which the connection to mains is interrupted.

Fig. 15 is a schematic view of an actuator system specifically adapted for use in a treatment chair 98. The controller 99 is provided with a power supply 100 connected to mains. The controller 99 drives the two actuators 101,102 for adjusting the profile of the chair. A battery pack 103 is connected to the controller 99 via the DC-bus 104 and can thus supply the controller 99 with electrical power, if the supply from mains is interrupted. The battery pack 103 is also charged via the DC-bus 104. The actuator system is wirelessly operated by means of a hand control 105 via a receiver 106 connected to the controller 99.

Fig. 16 is a schematic view of an actuator system specifically adapted for use in a reclining chair 107. The controller 108 is wirelessly connected 109 to an operating unit 110, which can activate both an actuator 111 and a massage motor 112 installed in the reclining chair 107. The power supply 113 of the controller 108 is supplied from mains and is via the DC-bus 114 connected to a primary cell 115 which, in the configuration depicted, is intended for temporarily being able to adjust the actuator 111 in case of an emergency in case mains is interrupted.