Resilient toothbrush

The invention concerns a toothbrush comprising a handle and a brush head, which is equipped on one side with clusters of bristles, a resilient connection being provided between the handle and the brush head. When pressure is exerted on the surface formed by the free ends of the clusters of bristles, the connection allows the brush head to be deflected relative to the handle. This is achieved in that the connection is formed by a hinged rectangle whose axes of rotation extend transversely to the longitudinal extension of the handle and the bristles, and in that the distance between the two hinges closest to the brush head is less than or equal to the distance between the two hinges closest to the handle.

FIELD OF INVENTION 
The invention concerns a toothbrush with a bristle carrier equipped with 
bristle bundles on one side, with a handle, and with an elastic connection 
between the handle and the bristle carrier, which makes possible a 
deflection of the bristle carrier with respect to the handle when pressure 
is exerted on the surface formed by the free ends of the bristle bundles. 
BACKGROUND OF INVENTION 
The toothbrush is still the essential and most reliable aid for 
indispensable dental hygiene. When using a brush to clean teeth, however, 
pressure is always exerted on the teeth with the bristles and thus 
unavoidably also on the gums. This pressure is measured out only with 
difficulty by human sensation and the hand, so that on one hand, a 
sufficient cleaning of the teeth and their gaps is brought about, and on 
the other hand, the gums are not injured by excessively high pressure. 
Toothbrushes available on the market, with an elastic brush head and as 
described, for example, in European Patent No. 0,371,293 A2, do not 
provide any remedy here since they are constructed in such a manner that 
the bristle head gives way with the pressure exerted, but the bristle 
surface is inclined away from the bristle head. This means that when 
pressure is exerted on the bristle head, the one-sided bristles are 
inclined away from the cleaning surface, but via the bristles on the side 
of the handle, the same unreduced pressure is exerted on a substantially 
smaller bristle surface. These toothbrushes are therefore not to be 
considered as an improvement but rather are to be evaluated as 
disadvantageous, since the risk of injury to the gums is not reduced, but 
rather is even increased by a smaller effective area of the bristle tips. 
European Patent No. 0,339,350 A1 describes a toothbrush whose brush head 
can be moved by a two-part handle, consisting of an upper part and a lower 
part, in such a way that the surface of the brush head can assume various 
angles with respect to the handle. The disadvantage of this brush consists 
in the fact that the inclination must by adjusted by the hand and there is 
no way of avoiding that either the bristles close to the handle or those 
of the tip of the brush are pressed more on the teeth and that therefore, 
there is no uniform pressure distribution over the entire bristle surface. 
Furthermore, a considerable application of force by the hand, which cannot 
be controlled and measured out for the desirable purpose, is required to 
change the angle of inclination. 
SUMMARY OF THE INVENTION 
The goal of the invention is, therefore, the construction of a toothbrush, 
which has an elastic bristle head, in such a manner that upon deflection 
of the brush head, the surface formed by the free bristle ends of the 
bristle bundle is not inclined away from the handle, but rather retains 
the parallel alignment with respect to the handle or inclines against the 
handle, so that it is always ensured that the full cleaning effect of the 
entire bristle surface is used and no pressure peaks with respect to the 
gums appear. 
The goal is thereby attained in that the connection is formed by a four-bar 
linkage, whose turning axes run transverse to the longitudinal extension 
of the handle and the bristles, and that the distance between the two 
links, facing the bristle carrier, from one another is smaller or the same 
as the distance between the two links, facing the handle, from one another 
.

The reference symbols given in the figures have the following meaning: 
1 Bristle carrier 
2 Link 
3 Link 
4 Diagonal tie rod 
5 Slide tie rod 
6 Link 
7 Link 
8 Slot 
9 Handle 
10 Bristles 
DETAILED DESCRIPTION 
The invention concerns a toothbrush with a bristle carrier (1), connected 
elastically with the handle (9), with bristle bundles (10) arranged 
therein on one side, which can be moved by exerting pressure on the 
surface of the bristle bundle (10) in such a way that the surface of the 
bristle bundle (10) always runs parallel to the handle (9) or is inclined 
against it. 
This is attained by a multiple-tie rod, preferably 2- or 3-tie rod 
connection between the handle (9) and bristle carrier (1), wherein the 
connecting sites of the tie rods (4,5), with the handle (9) or the bristle 
carrier (1), have the function of links (2,3,6,7). Diagonal tie rods (4) 
and slide tie rods (5) are preferably tapered at these points to increase 
the elastic link effect. An elastic effect can, however, also be attained 
by using a more elastic material in the area of the connecting points. 
In a preferred specific embodiment, the toothbrush, in accordance with FIG. 
1, has a diagonal tie rod (4) and a slide tie rod (5), in which the 
individual distances between the links (2) and (3) and (6) and (7) are the 
same. Upon exerting pressure on the bristle bundle (10), the surface of 
the bristle bundle (10) is displaced parallel to the handle (9), as shown 
in FIG. 5. 
If the toothbrush according to FIG. 1 is designed in such a way that the 
handle (9) is constructed thicker, in comparison to the bristle carrier 
(1), than the distance between the links (6) and (7) is larger than that 
between (2) and (3). Pressure on the bristle surface then leads to an 
elastic movement in such a way that the bristle surface is inclined toward 
the handle (9), as is shown schematically in FIG. 6.