Housing, in particular for an electrical tooth cleaning device, and process for producing it

A housing (1) for an electrical device for bodycare, in particular for a tooth cleaning device, is described in which electrical components (8), in particular a charger, surrounded by a casting compound (14) are arranged. The components (8) are connected by an electrical cable (10) which is placed through a cable orifice in the housing (1). The cable orifice (11) is arranged in an external wall (12) of the housing (1) and represents the only orifice in the housing (1) to the electrical components (8). To produce the housing (1), the casting compound (14) is introduced through the cable orifice (11) into the housing (1) by means of a loading device (13).

The invention relates to a housing for an electrical device for body care, 
in particular for a tooth-cleaning device, in which there are arranged 
electrical components which are surrounded by a casting compound and are 
connected to an electrical cable placed through a cable orifice in the 
housing. 
A housing of this type is known from commercially available electrical 
tooth-cleaning devices produced by the applicants. In these devices, the 
housing is provided with a cable stowing space which is divided from the 
region with the electrical components by a partition wall. The partition 
wall contains two orifices, the electrical cable connected to the 
electrical components being placed through one of the orifices. The other 
orifice serves for loading the casting compound into the region with the 
electrical components during production of the housing. For this purpose, 
a loading device is inserted into this orifice so the liquid casting 
compound can flow into the interior of the housing and can surround the 
electrical components. After the casting compound has been loaded, the 
loading device is removed again and the housing is set aside for the 
curing of the casting compound. The orifice in the partition wall remains 
without having a further use. 
An object of the invention is to provide a housing, in particular for an 
electrical tooth cleaning device, and a process for producing it which is 
improved with respect to the material required and the necessary 
production stages. 
The object is achieved in that the cable orifice is arranged in an external 
wall of the housing and represents the single orifice in the housing to 
the electrical components. 
According to the invention, the cable orifice is no longer provided in a 
partition wall but directly in the external wall of the housing. A 
partition wall or the like is no longer provided. The function of the 
partition wall, that is the separation of the electrical components from 
the cable stowing space, is adopted by the loaded casting compound. The 
resultant saving in material and reduction in the necessary production 
stages is obvious. 
A further advantage is that the casting compound surrounds not only the 
electrical components but at least some of the electrical cable. The 
tension in the electrical cable is therefore reduced so it is not 
necessary to take further measures in this respect. 
Furthermore, only a single orifice to the electrical components, namely 
said cable orifice, is provided according to the invention. This obviously 
also represents an improvement, in particular with respect to production 
of the housing according to the invention. 
The electrical cable can be introduced or removed through this cable 
orifice into the cable stowing space located behind it, as required. The 
cable stowing space has the advantage that, apart from the cable orifice, 
it is closed all round and is formed internally by substantially smooth 
faces. The electrical cable is protected and spared in this way. 
In an advantageous development of the invention, when the housing is 
vertical, the casting compound has a surface which is arranged either 
substantially horizontally or at an angle of inclination to the 
horizontal. With the last-mentioned alternative, in particular, that is 
with an inclined surface of the casting compound, it is possible, on the 
one hand, for the electrical components to be completely surrounded by the 
casting compound and therefore insulated but on the other hand for a 
smaller quantity of casting compound than hitherto to be required in the 
interior of the housing. This has the advantage that not only the material 
requirement is smaller but also that the cable stowing space is greater. 
In an advantageous embodiment of the invention, supporting ribs which are 
at least partially coated with casting compound are provided in the 
interior of the housing. The coating of the supporting ribs with casting 
compound has the advantage that the electrical cable cannot be damaged by 
the supporting ribs. 
It is particularly desirable if the electrical device for bodycare contains 
a re-chargable accumulator and the electrical components belong to an 
electrical charger. In the case of an electrical tooth-cleaning device, a 
user can use a hand-held device with a rotating bristle member separately 
from the mains voltage. For charging the accumulator contained in the 
hand-held device, the hand-held device has to be connected to the charger. 
This can be carried out, for example, by means of electric contacts or the 
like, the necessary charger being arranged in the housing according to the 
invention. 
With a process of the type mentioned at the outset, said object is achieved 
in that the casting compound is introduced into the housing through the 
cable orifice by means of a loading device. 
According to the invention, therefore, the cable orifice has a double 
function. On the one hand, it serves as an orifice for the electrical 
cable. On the other hand, however, the casting compound is also loaded 
through the cable orifice into the interior of the housing. For this 
purpose the loading device is introduced into the cable orifice when the 
electrical cable is put through and the liquid casting compound is 
introduced into the interior of the housing. Once the necessary quantity 
of casting compound is introduced, the loading device is removed again and 
the casting compound can solidify. The surface of the solidified casting 
compound then forms one of the faces of the cable stowing space. The 
electrical cable placed through the cable orifice and connected to the 
electrical components also sinks into this surface. 
In an advantageous embodiment of the invention, for loading the casting 
compound, the housing is brought, by means of a conveyor, into a loading 
position having a loading angle relative to the horizontal. The loading of 
the casting compound into the interior of the housing is substantially 
simplified in this way. 
In an advantageous development of the invention, for curing of the casting 
compound, the housing is brought by means of the conveyor, either into a 
substantially horizontal position or into a position having an angle of 
inclination to the horizontal. In this way, either the horizontal surface 
of the casting compound is produced or the surface arranged beneath the 
angle of inclination. 
It is advantageous if the housing is set on a corresponding oblique plane. 
The respectively desired angle of inclination for loading the casting 
compound or for curing the casting compound can therefore be produced in a 
particularly simple manner in terms of the process. For this purpose, the 
conveyor with the housing is conveyed up or down only said oblique plane 
and is set on the oblique plane for the loading or curing of the casting 
compound.

FIG. 1 shows a housing 1 for an electrical tooth cleaning device. The 
housing 1 is essentially composed of a substantially beaker-shaped upper 
part 2 and a substantially plane base 3 associated with the orifice in the 
upper part 2. On one side, the upper part 2 is provided with a projecting 
supporting member 4 starting from one edge of its beaker shape. The base 3 
extends into the region of the support member 4 and completely closes the 
orifice of the beaker-shaped upper part 2 and the support member 4. A 
nozzle 5 with a round cross section pointing substantially in the same 
direction as the beaker shape of the upper part 2 projects from the 
supporting member 4. 
If the housing 1 stands on the base 3 or is fastened in this position in a 
different way, the nozzle 5 points substantially vertically upwardly and 
the base 3 extends substantially horizontally. This enables a hand-held 
device pertaining to the electrical tooth-cleaning device to be placed 
with an associated recess on the nozzle 5. 
The hand-held device contains an electric motor which is driven by an 
accumulator. The bristles of a bristle member can be set into rotation by 
the electric motor. A user can therefore clean his teeth by means of the 
rotating bristles of the hand-held device when the hand-held device is 
removed. 
In order to recharge the accumulator, the user has to place the hand-held 
device on the nozzle 5 of the housing 1. Electrical energy is then 
transmitted to the hand-held device by inductive transmission. Appropriate 
means are provided in the hand-held device and in the housing 1 for this 
purpose, including a coil 6 in the housing 1. 
A printed circuit board 7 extending substantially over the entire orifice 
of the beaker-shaped upper part 2 is arranged substantially parallel to 
the base 3 in the housing 1. A number of electrical components 8 is 
arranged on the printed circuit board 7 and rigidly soldered to the 
printed circuit board 7. These electrical components 8 are, for example, 
electrical resistors, capacitors, transistors, etc. Overall, the 
electrical components 8 form an electrical charger for recharging the 
accumulator in the above-mentioned hand-held device. 
The printed circuit board 7 with the electrical components 8 is fixed 
within the housing 1 by means of supporting ribs 9. The supporting ribs 9 
project from the upper part 2 and extend substantially in the same 
direction as the beaker shape of the upper part 2. 
The height of the upper part 2 is selected to provide a free space, which 
will be described in detail, above the electrical components 8. 
An electrical cable 10 is rigidly connected to the printed circuit board 7 
and serves to supply electric energy, for example in the form of a mains 
voltage, to the charger so the printed circuit board 7 and the electrical 
components 8 carry current in the connected state. 
The electrical cable 8 is guided through a cable orifice 11 out of the 
housing 1. The cable orifice 11 is arranged in an external wall 12 of the 
beaker shape of the upper part 2, more specifically in the region of the 
free space in the upper part 2 which is to be described. The edge of the 
cable orifice 11 is externally and internally markedly rounded so there 
are no sharp or pointed edges. 
During production of the housing 1, the printed circuit board 7 with the 
electrical components 8 including the coil 6 and other means for inductive 
transmission is introduced into the upper part 2. The electrical cable 10 
is placed through the cable orifice 11. The upper part 2 is then firmly 
closed by means of the base 3. 
The housing 1 is now brought into a loading position, as shown in FIG. 1. 
In this loading position, the housing 1 has a loading angle a to the 
horizontal which is about 70 degrees to 80 degrees in the embodiment 
described. This loading angle a is selected such that the cable orifice 11 
is located in a substantially horizonal position. 
In the lower part of FIG. 1, the horizontal is shown as a line so the 
loading angle a is located, for example, between this line and the base 3. 
In terms of the process the loading angle a is achieved in that the housing 
1 is held on a conveyor with which the housing 1 is conveyed from one 
station to the next station of the production plant and in that this 
conveyor together with the housing 1 has to be moved up or down a 
corresponding oblique plane. Once the housing 1 is located on the oblique 
plane, the conveyor is stopped and the loading position is reached. 
In the loading position the housing 1 is allocated a loading device 13 
which can be, for example, a tubular loading nozzle. The loading device 13 
is now introduced into the cable orifice 11. A liquid casting compound 14 
is then loaded into the interior of the housing 1 by means of the loading 
device 13. The quantity of casting compound 14 to be loaded is selected in 
such a way in the present embodiment that the interior of the housing 1 is 
substantially half filled with casting compound 14. The loading device 13 
is then removed again. 
The horizontal surface of the loaded casting compound 14 in the loading 
position, that is with the housing 1 inclined, is identified by reference 
numeral 15 in FIG. 1. 
In a first embodiment, the housing 1 is brought into a substantially 
horizontal position after being loaded with the still liquid casting 
compound 14, as shown in FIG. 2. The horizontal is indicated by a line in 
the lower part of FIG. 2. The surface of the loaded casting compound 14 is 
identified by reference numeral 16 in FIG. 2. This surface 16 is arranged 
substantially parallel to the base 3, and the electrical components 8 
including the printed circuit board 7 are located in the region of the 
housing 1 filled with the casting compound 14. 
In a second embodiment which is shown in FIG. 3, the housing 1 is brought 
into an inclined position after being filled with the still liquid casting 
compound 14. In this curing position, the housing 1 has an angle of 
inclination b to the horizontal which is about 40 degrees to 50 degrees in 
the embodiment described. In the lower part of FIG. 1, the horizontal is 
drawn in as a line so the angle of inclination b is located, for example, 
between this line and the base 3. The surface of the loaded casting 
compound 14 is indicated by reference numeral 17 in FIG. 3. The high 
electrical components 8 are arranged on the printed circuit board 7 in 
such a way that they do not project beyond the surface 17. In the present 
embodiment, the high electrical components 8 are arranged according to 
FIG. 3 in the left-hand region of the printed circuit board 7 so the 
casting compound 14 can have a lower height in the right-hand region. The 
printed circuit board 7 and the electrical components 8 arranged thereon 
are therefore located completely in the region of the housing 1 filled by 
the casting compound 14. 
In the two embodiments described, the housing 1 is set in the positions 
shown in FIGS. 2 and 3. The liquid casting compound 14 can now cool and 
therefore solidify and cure. In the final analysis, this produces a rigid 
casting compound 14 with the surfaces 16 and 17 shown in FIGS. 2 and 3. 
The casting compound 14 serves to insulate the printed circuit board 7 and 
electrical components 8. 
In terms of the process, the desired curing position is achieved in the two 
described embodiments in that the housing 1 is moved over a corresponding 
plane by the conveyor and is then set aside. In the embodiment according 
to FIG. 2, the conveyor with the housing 1 is set on a horizontal plane 
and in the embodiment according to FIG. 3 on an oblique plane having the 
angle of inclination b to the horizontal. 
The aforementioned free space is produced in the interior of the upper part 
2 in both embodiments described in FIGS. 2 and 3. This free space 
represents a cable stowing space 18 into which the electrical cable 10 can 
be introduced or removed through the cable orifice 11. 
FIGS. 4 and 5 show the supporting ribs 9. As shown in FIG. 1, the 
supporting ribs 9 are completely surrounded by the casting compound 14 
during the loading of the liquid casting compound 14. As a result, the 
supporting ribs 9 retain a thin layer of the casting compound 14 even 
after the housing 1 has been tilted back from the loading position into 
the curing position. Owing to the surface tension of the liquid casting 
compound 14, this produces an irregular thickness in the layer of casting 
compound 14 located on the supporting ribs 9. This in turn means that the 
height of the supporting ribs 9 becomes smaller and the radii of the 
supporting ribs 9 to the surfaces of the housing 1 become greater. 
Therefore, the supporting ribs 9 have no sharp or pointed edges.