GB2030855A

GB2030855A - Electric tooth-brush

Info

Publication number: GB2030855A
Application number: GB7929635A
Authority: GB
Original assignee: Rowenta Werke GmbH
Current assignee: Rowenta Werke GmbH
Priority date: 1978-09-14
Filing date: 1979-08-24
Publication date: 1980-04-16
Also published as: JPS5540597A; NL7905590A; FR2435927A1; DE2839911A1

Abstract

An electric tooth-brush comprises a brush head 1 and a housing 8 containing a power source (2), a drive motor 4 and a switch 3 for connecting the source to the motor. The switch 3 comprises semiconductor elements and has an operating electrode 6 connected to a conductive shaft 11. Conductive contact of electrode 6 with a user's mouth is established via a moisture film in a groove 15 to turn on the switch. The head 1 may alternatively be conductive or porous. A blocking button 12 connected to a blocking electrode 10 enables the brush to be turned off while in the mouth. Alternatively, the brush may have a ring conductor (7) or parallel longitudinal strips around the housing 8 or within the housing for conductive or capacitive coupling to the user's hand. Two operating electrodes connected to two conductors may be provided and arranged to be bridged, e.g. by a finger. <IMAGE>

Description

SPECIFICATION Electric tooth-brush The invention relates to an electric tooth-brush consisting of brush head and a housing containing a voltage source, a drive motor and a switch for connecting the source to the motor.

It is known with tooth-brushes of this type to make by means of a switch an electrical connection between the working motor and the energy source, whereby the energy source may vary depending on the design of the tooth-brush. Eitherthe motor is operated directly with mains voltage or the toothbrush employs a transformer, whereby a battery may additionally be present as energy accumulator.

Various tooth-brushes with the above-mentioned power supplies are known, with which the electrical connection to the motor is made by means of a mechanical switch. The use of such a switch has various disadvantages. Since the tooth-brush must remain in operation in all the different ways in which it can be held, the switch must be made to engage. It is therefore necessary to provide on the switch, besides the electrical contacts, a mechanical device which causes engagement and which makes the switch correspondingly more expensive and is also subject to wear. Since the connected motor power is considerable with electric tooth-brushes, there arises also on the switches a high contact load which likewise leads to wear and a gradual increase of the contact resistance.Furthermore, such switches must be water-tight themselves and be connected to the housing likewise in a water-tight manner. The penetration of water into an electrical appliance which, on the one hand, is introduced into the mouth and, on the other hand is used in bathrooms in which generally direct body contact with tiled floors or walls or with wash-basins, water pipes and the like creates a good earth contact is extremely dangerous for the user. The sealing and assembly of these switches are therefore expensive and costly. Furthermore, a conventional switch is always a shaped element which must be integrated into the overall form of the tooth-brush and to which the housing as a whole must be adapted, due to which additional costs are incurred.

The decisive disadvantage of such an arrangement with a switch which operates when the brush is pushed against the teeth is that during use a constant pressure must be applied with the brush part against teeth, gums, jaw and palate. Every relaxation of pressure causes the drive to be switched off. The constant pressure required excludes of itself the use of such tooth-brushes in an inflamed or sensitive oral region.

A further disadvantage resides in the switch which is extremely expensive from a mechanical point of view and whose contacts must remain closed despite the movement of the brush shaft.

Starting from this state of the art, the problem of the invention is to provide an electric tooth-brush which, with the avoidance of the above-mentioned disadvantages, can be switched on easily, is conve nientto handle and can be manufactured at moderate cost and with favourable shaping.

According to the invention, there is provided an electric tooth-brush comprising a brush head and a housing containing a voltage source, a drive motor and a switch for directly or indirectly connecting the source to the motor, wherein the switch comprises semiconductor elements and has an operating electrode connected to at least one electrical conductor positioned in or on the housing or extending therefrom, whereby the switch may be operated by conductive or capacitive coupling of a user's body with the conductor(s).

The conductor may surround the housing or it may be arranged on the inner face of the housing.

According to another form of construction of the invention, a blocking electrode is arranged in the switch and the operating electrode is connected to an electrically conducting brush shaft extending from the housing and the blocking electrode is connected to a conductor mounted on the housing. The brush head may have a shaped surface and/or consist of porous material to forms in the region of its connection to the brush shaft a continuous conductive path when wet. The brush head may also be wholly or partly electrically conductive.

Another possible solution consists in that the switch employs two operating electrodes and conductors and is actuable by bridging these conductors, for example with a finger.

It is thereby ensured that the operating contacts can be effected on the surface of the tooth-brush and can be cast therewith in the simplest manner. The annular arrangement according to the invention, which can likewise be executed in the form of parallel longitudinal strips, may be made of conductive material which is laid into the plastic of the toothbrush housing. Due to the invention, sealing problems in the region of the switch do not arise. In addition, operation is substantially simplified, since no switch has to be actuated mechanically. The toothbrush is in operation when the handle part is taken in the hand and stops automatically when it is put down. Moreover, a touch switch is completely free of wear.Furthermore, it is possible with a corresponding design of the switch to connect the operating electrode to an annular conductor serving as antenna at the inner wall of the housing. This conductorthen serves as a receiverforthe electric field applied by the holding hand at the outer surface of the housing. The signal received by this antenna can after corresponding processing actuate the true switch. This form of construction has the advantage that no contact at all with the outer surface of the housing needs to be effected. In further forms of construction the brush shaft and the brush head themselves serve as the operating conductor. After the brush head is moistened, there forms on the surface a closed water film which makes a conductive connection with the brush shaft and consequently with the switch.The contact alone of the brush head with the teeth or the mouth region causes the electric tooth-brush to be switched on. In this case, the blocking contact enables prevention of the toothbrush from starting when tooth-paste is applied or when the brush head is changed.

Exemplary embodiments of the invention are described in detail hereinafter by reference to Figures 1 to 4 wherein: Figure lisa partial section of a possible embodiment of the electric tooth-brush according to the invention without brush body; Figure 2 is a section of another embodiment without brush body; Figure 3 is a partial section of a further possible embodiment with brush body; Figure 4 is a partial section of an embodiment with brush body.

The electric tooth-brush according to Figure 1 shown by way of example consists of a housing 5 in which a battery is arranged as voltage source 2 for the drive 4 of the brush shaft 11. Fastened in the housing shell 8 is an annular electrical conductor 7 which is connected electrically to a switch 3 via an operating electrode 6. Actuation is effected by direct contact of the electrical conductor7 with the user's hand.

In the modified embodiment shown in Figure 2 the electrical conductor7 is arranged on the inner face 9 of the housing shell 8. This embodiment is actuated by capacitive contact between the user and the conductor 7 arranged on the inner wall 9 of the housing shell 8.

Figure 3 shows a further possible embodiment of the electric tooth-brush according to the invention, in which the function of the electrical conductor 7 according to Figures 1 and 2 is assumed by the brush shaft 11. The brush head 1 has a groove 15 which is connected, on the one hand, to the brush 14 and, on the other hand, to the brush shaft 11. This appliance is actuated by a direct contact of the user's oral region with the brush 14. The water film in the groove 15 serves as electrical conductor between the brush 14 and brush shaft 11. Alternatively, the brush head may be made of a porous material or may be wholly or partly electrically conductive.

The further embodiment shown in Figure 4 differs from the embodiment according to Figure 3 in that there is arranged on the switch 3 a blocking electrode 10 which is connected to a blocking button 12 provided on the housing 5 and in that the brush shaft 11 is connected to the groove 15 via a bore 13. By actuation of the blocking button 12 the user has the possibility of switching off the appliance without having to take the brush 14 out of his mouth.

In another form the switch 3 may have two operating electrodes connected respectively to two conductors. The switch may then be operated by bridging the two conductors, for example with a finger.

Claims

1. An electric tooth-brush comprising a brush head and a housing containing a voltage source, a drive motor and a switch for directly or indirectly connecting the source to the motor, wherein the switch comprises semiconductor elements and has an operating electrode connected to at least one electrical conductor positioned in or on the housing or extending therefrom, whereby the switch may be operated by conductive or capacitive coupling of a user's body with the conductor(s).

2. An electrictooth-brush as claimed in claim 1, wherein the conductor surrounds the housing.

3. An electric tooth-brush as claimed in claim 1, wherein the conductor is arranged on the inner face of the housing.

4. An electric tooth-brush as claimed in claim 1, wherein the operating electrode is connected to an electrically conducting brush shaft extending from the housing.

5. An electric tooth-brush as claimed in claim 4, wherein the brush head has a shaped surface and/or consists of porous material to form in the region of its connection to the brush shaft a continuous conductive path when wet.

6. An electric tooth-brush as claimed in claim 4 or 5, wherein the brush head is wholly or partly electrically conductive.

7. An electric tooth-brush as claimed in claim 4, 5 or 6 wherein the switch comprises a blocking electrode connected to a conductor mounted on the housing for turning off the motor when the shaft is coupled to a user's body.

8. An electric tooth-brush as claimed in claim 1, wherein the switch employs two operating electrodes and conductors and is actuable by bridging these conductors, for example with a finger.

9. Electric tooth-brushes substantially as hereinbefore described with reference to the accompanying drawing.