Especially, the present invention will be described in the field of mobile dental equipment, where the external units are the different equipment used by dentists, but the inven- tion is equally applicable in eg robotics where a number of external units, such as sensors, transducers or the like, are controlled by a central means.

A problem often encountered in this type of equipment is that of the assembly thereof comprising the assembly of a large number of plugs for different units. A large variety of plugs are used-and often different types of plugs depending on the requirements thereof: the power to be transferred and the information (amount and type) to be transferred. This is a problem not only when assembling the apparatus but also when designing and manufacturing it, in that a large number of different plugs may need to be purchased, stored etc.

This problem is addressed by the present invention, a first aspect of which relates to an apparatus comprising: -a power supplying unit, -a plurality of units external to the power supplying unit, the external units being detachably connectable to the power supplying unit, the power supplying unit being adapted to supply power to the external units, the power supplying unit comprising means for generating controlling information for use in controlling the operation of the external units,

each external unit comprising: -at least one device requiring power, and -means for controlling the operation of the at least one device, wherein the external units comprise engaging means for engag- ing with corresponding engaging means of the power supplying unit or other external units in order to transfer power and controlling information from the power supplying unit to the external units, the engaging means of the external units being substantially identical.

Thus, a number of external units are controlled centrally from the power supplying unit and via substantially identical engaging means, typically a type of plug.

Preferably, the information transmitted to and via the engag- ing means of the power supplying unit and to those of the external units are the same. Also, the power transferred to the external units is delivered from the same source without any individual adaption. Therefore, the controlling means of the external units are preferably adapted to adapt the received power and information to those required by the device or devices of the external unit.

In this manner, identical or substantially identical engaging means may be used in the external units, and these means may be brought into engagement with any one of the one or more engaging means of the power supplying unit, as the control- ling means of the external units may convert or transform the power and information received to suit the needs or demands of the device or devices of that external unit.

This aspect, thus, alleviates the assembly and manufacture of such apparatus in that all engaging means, such as plugs, of

the external units may be brought into engagement with any one of the one or more engaging means of the power supplying unit-without any change in the operation of the apparatus.

This makes this type of apparatus more fool proof and fur- thermore drastically reduces the number of different engaging means which need be purchased, stored and used.

In the present context,"substantially identical§ means that the engaging means of all external units are adapted to engage with any of the one or more engaging means of the power supplying units, so that the operation of the apparatus is independent of whether, eg, the positions of two engaging means of two different external units are interchanged (as long as they were both in engagement with the power supplying unit).

Thus, all engaging means of the external units should be compatible with those of the power supplying unit.

Preferably, the engaging means of the power supplying unit comprise a number of electrically conductive means relatively positioned in a given manner, and wherein the engaging means of the external units comprise the same number of and corre- spondingly relatively positioned electrically conductive means.

Thus, preferably, the engaging means of the external units are in the shape of male plugs comprising a number of legs positioned at predetermined positions. In this situation, the engaging means of the external units preferably have the same number of legs and positioned in the same manner so that all engaging means of the external units may engage the engaging means of the power supplying unit.

In one embodiment, the engaging means of the external units and the power supplying unit comprise separate means for

transferring power and controlling information from the power supplying unit to the external units.

In order to facilitate the use of any number of external units without having to provide the power supplying unit with an excessive number of engaging means, the engaging means of at least part of the external units may comprise both means for engaging with the engaging means of the power supplying unit and the engaging means of at least one other external unit. This aspect is known from eg certain telephone con- nectors which are provided with both a male plug (for plug- ging into eg a wall plug) and a female plug (for receiving a male plug from eg an answering machine).

In this manner, any number of engaging means (and, consequently, any number of external units) may be connected to each other and finally to the power supplying unit. Nat- urally, this structure is the most applicable in the situ- ation where the information and power (typically the voltage) supplied to the external units are the same.

In order to ensure stable operation of the apparatus, the engaging means of the external units may comprise means for fastening the engaging means of the external units to the engaging means of the power supplying unit or of other exter- nal units.

As described above, the power and information supplied to the individual external units may be the same. In this situation, each device of an external unit typically has specific power requirements, and the controlling means of the external unit is preferably adapted to adapt the power received from the power supplying unit to the requirements of the device.

In this situation, the controlling means may also or op- tionally be adapted to protect the device from excessive current or voltage, such as sparks or the like.

In order to adapt any voltage and/or current received from the power supplying unit to any needs of a device of an external unit, the controlling means preferably comprise voltage and/or current transforming means for transforming a voltage and/or current received from the power supplying unit to a desired, predetermined voltage and/or current required by the device.

In this manner, the power supplying unit may perform the task of simply providing any power (current and/or voltage) that it is able to-depending on eg its state of charge (if it comprises a battery) or any power it itself receives- whereafter the individual external units transform it into that required by the device (s) thereof.

In addition, the controlling information generated by the generating means-or any information relating thereto-may be transferred to all engaging means of the power supplying unit and therefrom to those of the external units, as the further controlling (if any) of the device (s) of the external units based on the information is taken care of at the indi- vidual units.

This controlling information may be directly forwarded to the engaging means of the external units, or it may be converted, transformed or interpreted in any suitable manner, before being transmitted to the external units. A central treatment may be performed of this information at the power supplying unit as opposed to a decentralized treatment in the individ- ual controlling means of the external units.

One situation where a centralized treatment may be desired is one where a standard information protocol has been defined and programmed in the controlling means of the external units. In this situation, providing a new type of controlling information or a new means for generating such information at the power supplying unit may require the adaption of this new information to suit the previously defined protocol.

However, in certain circumstances, it may not be desired to maintain this structure of autonomous units. It may be desired that the controlling means of at least part of the external units are adapted to communicate with each other in order to eg coordinate the operation of the external units.

This coordination may be that of coordinating power consump- tion, if the power available from the power supplying unit is not sufficient.

This coordination may be based on a priority list of the external units or the devices thereof, so that the most important ones receive the power needed in order to operate.

Thus, the controlling means may communicate in order to optimize the power consumption of the at least part of the external units.

Another situation where coordination may be desired is one where information from one device, such as a sensor, is required in the controlling of another device, such as a transducer or a movable element, of another external unit.

Also, the controlling means may be adapted to also communi- cate with the controlling means of the power supplying unit.

This may be in order to determine the state of charge etc. of the power supplying means or in order to adapt or control a transformation of the information from the generating means into the information transmitted to the engaging means and the controlling means of the external units.

Naturally, the structure of the external units may vary with eg the actual use thereof. Especially in the field of mobile dental equipment, the controlling means of an external unit preferably constitute part of the engaging means of that external unit. In this manner, the controlling means may not be present at the devices thereof, which may then be or at least resemble those typically used in eg a dental clinic.

In this situation, the devices of the external units may be those normally used for the actual use.

The power supplying unit may further comprise rechargeable power supplying means and controlling means for controlling discharging and charging of the power supplying means. Nat- urally, rechargeable batteries or the like are desired in mobile equipment-such as mobile dental equipment for use in areas where no dental clinics exist or even where standard power sources do not exist-but also in robots, which are preferably not equipped with power cables to external power sources. A number of the preferred types of eg rechargeable batteries, such as Lithium batteries, require rigorous con- trol of their charging and discharging in order not to damage the battery cells.

The rechargeable power supplying means may be rechargeable on the basis of power generated by or received from any power source, such as from the group consisting of solar cells, wind power generator, combustion engines, car batteries, and domestic power grid, depending on the place of use and on the power available.

As described above, one preferred apparatus according to this first aspect of the invention is where the apparatus forms part of mobile dental equipment, the devices of the external units being chosen from the group consisting of: dental drills, light emitting devices, such as for emitting visible or ultra violet light, suction devices, pumps, such as for providing water or air.

Especially, but not solely, in this situation, the means for generating controlling information preferably comprise switching means adapted to be operated by a foot of an oper- ator.

In another aspect, the invention relates to a method of operating the above described apparatus according to the

first aspect of the invention, the method comprising the steps of: -generating, using the generating means, controlling information relating to a desired operation of one or more external units, -transferring the controlling information or information relating thereto to the controlling means of the one or more external units, the information being transferred via the engaging means of the one or more external units and of the power supplying unit, -controlling, using the controlling means of the one or more external units, the operation of the at least one device of the one or more external units.

Thus, preferably at least substantially the same information is transmitted to the engaging means of all external units, and the treatment thereof (identification of whether the information relates the actual unit, in that case, decoding or transforming the information in order to derive what operation is desired, etc. etc.) is performed in the actual unit.

Similarly, the individual external units preferably receives substantially the same power (voltage and/or current) from the power supplying unit, and the adaption to the individual device (s) is performed in the external units.

In the following, a preferred embodiment of the apparatus according to the invention will be described for use in mobile dental equipment, wherein Fig. 1 shows a pedal controlled mobile power supply with 4 connection plugs,

Fig. 2 shows an electronic block diagram of a Central Unit (CU) and an Application Specific Module (ASM), Fig. 3 shows an electric circuit for a battery charger, Fig. 4 shows an electric circuit for a lamp module of the Application Specific Module (ASM) type, Fig. 5 shows an electric circuit for a motor control module of the Application Specific Module (ASM) type, and Fig. 6 shows an electric circuit for receiving signals from the switches connected to the pedals.

An apparatus according to the present invention is displayed in Fig. 1. The apparatus comprises a power supplying module 2 and three switches 4,6, and 8 for generating controlling signals to control the function of external modules 10,12, 14,16. The external modules 10,12,14,16 may be variable speed motor modules or modules providing light, such as light for a mirror and ultra violet light for plastic polymerisation. The power supplying module 2 comprises elec- tronics 100 including a pack of rechargeable batteries 108.

The external modules 10,12,14, and 16 may be electronically connected to the power supplying module 2 by means of female plugs 20 in the power supplying module 2 and corresponding male plugs 22 in the external modules 10,12,14, and 16. The ASM's 10,12,14, and 16 also comprise a fastening means 24 for safely fastening the ASM's 10,12,14, and 16 to the power supplying module 2. Via a plug 18 an external power supply may be connected to the power supplying module 2 for recharging the rechargeable batteries. The switches 4,6,8 are connected to one pedal A, B, C each, which pedals A, B, C may be handled by the operator of the apparatus.

Fig. 2 shows an electronic block diagram of a Central Unit (CU) 100 which is positioned in the power supplying module 2.

The CU 100 comprises a Power Plug 18,104 for connecting the

External Power 102. A Power Storage 108 receives the electri- cal power from Power Plug 18 via a Charger 106. The Charger 106 controls the power to the Power Storage 108, so as not to overcharge the Power Storage 108. The CU 100 also comprises three inputs 120 for providing controlling signals to the CU.

The input 120 is electronically connected to the switches 4, 6,8 of the power supplying module 2. The input 120 from the switches 4,6,8 passes through an ElectroStatic Discharge protection unit 118 to a Communication Encoding unit 116. The ElectroStatic Discharge protection unit 118 protects the Power Supplying Unit 100 against electrostatic discharge, such as high currents created by static electricity or abuse of the Power Supplying Unit 100. The Communication Encoding unit 116 reads the input 120 and processes the signal before sending it via the ElectroStatic Discharge protection unit 114 to the Plug 112. The Communication Encoding unit 116 processes the input by shaping the pulses to be rectangular for easy reading by the Decoding unit 206.

Fig. 2 also displays a block diagram of the electronics of an Application Specific Module (ASM) 200 comprised in each of the external modules 10,12,14,16. The ASM 200 controls a tool or device 208, and provides it with controlling signals and power. The ASM 200 is connected to the Central Unit 100 using the Plugs 202 and 112 respectively. The signals from the Plug 202 are sent via an ElectroStatic Discharge protec- tion unit 204 to the Micro Controller Communication Decoding unit 206. The Micro Controller Communication Decoding unit 206 decodes or transforms the signals to commands and decides if the actual command is to be carried out by that specific ASM 200, or if the actual command is meant for another ASM 200 and therefore should be neglected. The Power Manager 210 receives power from the CU 100 and provides power to the tool or device 208, which also receive control signals from the Micro Controller Communication Decoding unit 206.

A number of ASM 200's may be connected to the Central Unit 100. Each ASM 200 may be controlled by one or more signals

from the inputs of the CU 100. When the CU 100 receives signals from the switches 4,6,8, the signals are sent to all the ASM 200's connected to the CU 100. If an ASM 200 matching the signals is connected to the CU 100, the ASM 200 carries out the command, otherwise the command is dis- regarded.

In the presently preferred embodiment six different commands has been implemented. By pushing pedal A shortly, correspon- ding to pushing switch 4 shortly, a command for turning on or turning off a motor is issued. If an ASM 100 controlling a motor is connected to the CU 100, the ASM 100 will turn off the motor if it is already running, and turn on the motor if it is not running.

By pushing pedal A for a longer period of time, a command for increasing the speed of the motor is issued, an to decrease the speed of the motor, the operator of the apparatus must push the pedal B, corresponding to switch 6, for a longer period of time. As long as pedal A or pedal B is pushed, the motor will increase or decrease the speed. This means that if the operator wishes the motor to run at a high speed, he should push pedal A until the desired speed has been reached.

Controlling the speed of the motor is currently performed by a switch mode power supply provided in the ASM 100 control- ling the voltage supplied to the motor. The same technique may, naturally, be used for controlling the illumination of lamps etc.

By pushing pedal B shortly, corresponding to pushing switch 6 shortly, a command for turning on or turning off a mirror light is issued. If an ASM 100 controlling a mirror light is connected to the CU 100, the ASM 100 will turn off the light if it is already on, and turn on the light if it is off.

By pushing pedal C shortly, corresponding to pushing switch 8 shortly, a command for turning on or turning off a general

light is issued. If an ASM 100 controlling a general light is connected to the CU 100, the ASM 100 will turn off the light if it is already on, and turn on the light if it is off.

By pushing pedal C for a longer period of time, a command for turning on or turning off a plastic polymerisation light is issued. If an ASM 100 controlling a plastic polymerisation light is connected to the CU 100, the ASM 100 will turn off the light if it is already on, and turn on the light if it is off.

In Fig. 3 an electric circuit for a battery charger is shown.

The charger corresponds to the Charger 106 of the Control Unit 100.

In Fig. 4 an electric circuit for a lamp module of the Appli- cation Specific Module (ASM) type is shown, and in Fig. 5 an electric circuit for a motor control module of the Applica- tion Specific Module (ASM) type is shown. Both these elec- tronic circuits may be comprised in an external unit 10,12, 14,16.

Fig. 6 shows an electric circuit for receiving signals from the switches connected to the pedals. The block titled Sanyo displays the electric circuit shown in Fig. 3. Both these circuits are comprised in the power supplying module 2.