GB2040160A - Toothbrush - Google Patents

Abstract

A toothbrush having a stem-like grip 1 and a front portion 2 as bristle carrier adjoining said grip, the stem-like grip extending conically rearwardly, the bristle carrier 2 being rounded on its back and extending at an angle between 25 DEG to about 35 DEG to the centre axis of the grip, there being a bend region in which the grip tapers conically in the direction towards the bristle carrier to form a slight rear-side depression 4, the bristle zone 6 being disposed in the front portion of the bristle carrier 2, and being directed towards the centre axis of the grip over a region of less than half the length of the bristle carrier 2. <IMAGE>

Description

SPECIFICATION Toothbrush The invention relates to a toothbrush having a stem-like grip and a front portion as bristle carrier adjoining said grip.

Apart from the cosmetic function, the object of dental care is to preserve the teeth for as long as possible in a healthy state. The essential steps adopted to achieve this object reside in the mechanical and chemical cleaning of the teeth and the spaces between the teeth, first to counteract prophylactically tooth and gum complaints and secondly to remove or counteract the cause of bad breath. For this purpose, an essential mechanical aid is the toothbrush in conjunction with a toothpaste.

Although the great majority of toothbrush users do not assign any importance to the different forms and design of toothbrushes in dental care, it is known that for example brushing too firmly and rubbing with very hard bristles can injure the gums and damage the dental enamel. To achieve the objective of dental care, the removal of the film over the teeth, and food residues from the spaces between the teeth, the correct cleaning technique, regular cleaning and adequate cleaning time are required rather than strong mechanical forces. It follows from this that for optimum dental care the toothbrush must have certain properties, firstly to minimise the disadvantageous mechanical forces as far as possible and secondly to permit a relatively long cleaning time.Tests have shown that the toothbrushes hitherto known do not permit optimum movement cycles and consequently have effects which tend to cause the user to reduce the cleaning time.

The toothbrushes hitherto known and of substantially rectilinear configuration, require an arm and hand posture which in the great majority of users, causes muscle tensioning in the neck and arm region, which leads to shortening the cleaning time.

Practical observations show that usually in dental care the toothbrush is guided with the elbow raised to a greater or lesser degree, the up and down or to and fro cleaning movement coming from the upper arm and forearm and leading in conjunction with the force transmission thus necessary to the toothbrush to an excessively firm gripping of the toothbrush.

Due to the continuously raised elbow during cleaning, pronounced posture tensions arise as well as rapid tiring of the shoulder and arm muscles.

Excessive muscle tensions necessarily lead to hasty cramped and inaccurate cleaning movements, exaggerated application pressure, and to the user a shortening of the cleaning time.

Because of the anatomical situation, movement cycles can only be optimized if the tools used for the treatment have an optimum ergonometric design.

This is not true of known toothbrushes. Thus, with regard to dental care requiring adequate cleaning time, accurate guiding of the movement cycles and avoidance of excessive pressure, it is desirable to minimise the forces which must be exerted by the muscle so that the cleaning movements are still carried out in a controlled, uniform manner without excessive tiring even after an optimum cleaning time of about 90 seconds.

The problem underlying the invention is thus to provide a toothbrush which due to its erogonometric design and shape contributes to facilitating the movements during dental care and to making an accurate handling possible, with a controlled application pressure, in order to reduce the movement forces and the work involved in holding the brush and to make it convenient for the user to increase the cleaning time.

This problem is solved according to the invention by the combination of the following features: a) the stem-like grip extends conically rearwardly and has a preferably substantially circular crosssection; b) the bristle carrier is rounded on its back and extends at an angle between 25 to about 35 to the centre axis of the grip; c) in the bend region the grip tapers conically in the direction towards the bristle carrier to form a slight rearside depression; d) the bristle zone is disposed in the front portion of the bristle carrier directed towards the centre axis of the grip over a region of less than half the length of the bristle carrier.

With a toothbrush design according to the invention the advantage is achieved that the movement cycles take place with the minimum force expenditure. The combination of the features according to the invention also allows the cleaning operation to be carried out with a relaxed posture with a freely hanging upper arm, the cleaning movement originating only from the wrist and the toothbrush being guided deliberately only by thumb and index finger.

Since this handling requires less holding force and minimises the musclar force employed for the movement, muscular cramp is avoided and this automatically leads the user to increase the cleaning time.

In order firstly to make the guiding between thumb and index finger still more reliable and secondly to adapt the toothbrush to different hand sizes, a grip depression known per se is provided in the transition region between the grip and bristle carrier and the grip depression extends over the entire bend region into the bristle carrier. This results in various possible gripping actions. The grip may be held very individually.

Afurther development particularly expedient for gripping and holding the grip of the toothbrush is achieved in thatthe grip with a length of about 120 mm to 140 mm has at its thickest region a diameter of about 12 mm and at its rear end a diameter of less than 6 mm, preferably 3 mm.

The circular form of the grip provides a very uniform pressure distribution on the grip and thus facilitates the force transmission from the hand to the grip.

However, according to a further development the grip is made slightly elliptical in cross-section, thus enabling the guiding accuracy to be improved for certain applications.

For exact guiding and minimum force expenditure with relatively relaxed muscles it is particularly advantageous for the angle between bristle carrier and centre axis of the grip to be about 30 .

To adapt the toothbrush to different hand sizes the grip depression preferably extends about 20 mm into the grip and about 25 mm into the bristle carrier.

It is particularly advantageous for handling the toothbrush and especially for enabling a very accurately guided rolling movement, if the bristle zone has a length of about 70 to 80 mm of the bristle carrier and extend over a distance of about 20 to 30 mm at the front end of the bristle carrier. The surface receiving the bristles may be planar or alternatively trough-shaped. The trough-shape form is particularly advantageous because with a flatly cut bristle zone the bristles of the zone in the centre area are somewhat longer than the bristles in the edge region. As a result the bristles in the centre region of the zone become somewhat softer as is desired in order to reduce wrong mechanical stresses on the teeth and improve the cleaning operation.

A reduction of the mechanical forces on the teeth and the gums can also be achieved by making the individual bristle groups in the bristle zone sperical at the upper ends.

In orderto make the invention clearly understood reference will now be made to the accompanying drawings which are given by way of example and in which: Figure 1 shows a toothbrush according to the invention in side elevation; Figure 2 shows the toothbrush according to Figure 1 in plan view; Figure 3 is a section along the line Ill-Ill of Figure 1; Figure 4 is a section along the line IV-lV of Figure 1; Figure 5 is a section through a further development of the bristle carrier with a trough-shaped surface receiving the bristles; and Figure 6 is a perspective view of a toothbrush according to the invention held by hand.

In Figures 1 and 2 the toothbrush according to the invention is shown in side elevation and plan view.

The toothbrush consists of a stem-like grip 1 having a circular cross-section which at its thickest region has a diameter of about 12 mm and tapers conically to the rear end, the diameter in front of the rounded rear end being about 5 mm. Extending from this stem-like grip lisa bristle carrier 2 at an angle of about 30 to the centre axis of the grip 1. In the bend region a the grip tapers also in the direction towards the bristle carrier 2 so that a depression 4 is formed on the back of the toothbrush in the transition region to the bristle carrier 2. On the front of the bend region, a grip depression 5 extends from the grip over the entire region into the bristle carrier 2. The bristle carrier 2 itself is made elongated and flat and has a planar surface receiving the bristle zone 6.The bristle zone covers only the front portion of the carrier over a distance which is less than half the length of the carrier. The back of the carrier is rounded as apparent from Figure 4.

In a further development of the bristle carrier according to Figure 5 the surface receiving the bristle zone is trough-shaped and as a result the bristles in the centre area of the bristle zone are somewhat longer than the edge bristles.

In a preferred embodiment of the toothbrush, the grip 1 has a length of about 120 mm and the bristle carrier has a length of about 75 mm. The bristle zone 6 extends over a length of about 20 - 30 mm, the bristle zone having a height of about 8 to 9 mm in order to reduce the cleaning resistance. The thickness of the bristle carrier is about 4.5 mm and the width of the planar surface is about 10 mm. As aiready mentioned, the grip 1 has a maximum diameter of about 12 mm and tapers up to its rear end to a diameter of about 5 mm. The grip trough extends over the bend region about 20 mm into the grip 1 and about 20 mm into the bristle carrier 2.

The bristle zone 6 is preferably cut planar and the cut edge of the individual bristles is rounded as far as possible to prevent danger of injury. As particularly advantageous as regards to reducing the danger of injury is a bristle zone whose individual bristle groups are spherically rounded at their upper ends.

This form is not shown in the drawings.

Figure 6 illustrates how the toothbrush is held in use. The view of the hand shown is one as seen by the user looking at his hand in front of him, holding the toothbrush correctly. The toothbrush is brought out of the position illustrated by turning the hand through 180 into the position from which the cleaning of the teeth is effected. In the cleaning movement the bristle zone is moved substantially from the top to the bottom. For bushing the teeth from front to back and vice versa the toothbrush is guided as a whole with the hand by movement from the shoulder joint with the upper arm hanging freely.

Such a handling of the toothbrush gives optimum movement cycles with minimum force expenditure both as regards the movement of the toothbrush and for holding the toothbrush. The method of holding the toothbrush described automatically promotes the up and down movement of the bristle zone, i.e. in the longitudinal direction of the tooth gaps, which is regarded as particularly advantageous for the cleaning operation. Due to the cleaning movement with the upper arm hanging freely, cramp of the hand due to the holding effect and excessive muscularten- sioning in the shoulder region and in the elbow and upper arm are avoided, greatly reducing the fatigue and leading automatically to an increase in the average time of cleaning. Due to the specific shape of the toothbrush and the resulting handling thereof, excessive scraping of the teeth is hardly possible because the application pressure is reduced. It has been determined with the aid of tests that when changing from conventional toothbrushes to the toothbrush according to the invention, test persons automatically increased the average cleaning time from about 22 to 26 seconds with conventional brushes to usually more than twice this time with the brush according to the invention.

In the embodiment of the toothbrushes (not shown) for small hands, the tapering extending from the maximum grip diameter towards the bristle carrier also extends into the bristle carrier and effects a constriction of the latter between the bend region and the bristle zone. This constriction leads essentially to a reduction of the width of the bristle carrier in this region. The reduction of the width of the bristle carrier may also be combined with a shortening of the portion of the grip depression extending into the carrier.

The essence of the idea underlying the invention may also be realised in an electric toothbrush by replacing the stem-like grip by the grip of the electric toothbrush in which the drive motor is accommodated. The drive motor performs the cleaning movement so that the cleaning operation can be carried out not only with a relaxed posture and freely hanging upper arm but also with a substantially stationary hand. It is possible either two provide a toothbrush attachment with a bend of about 25 to 35 which may be fitted onto a rectilinear drive pin or to use a conventional rectilinear toothbrush attachment which may be fitted onto a drive pin which itself is bent at an angle of about 25 - 35 to the longitudinal direction of the grip.

Claims (11)

1. Atoothbrush having a stem-like grip and a front portion as bristle carrier adjoining said grip, the stem-like grip extending conically rearwardly and having a preferably substantially circular crosssection, the bristle carrier being rounded on its back and extending at an angle between 25 to about 35 to the centre axis of the grip, there being a bond region in which the grip tapers conically in the direction towards the bristle carrier to form a slight rear-side depression, the bristly zone being disposed in the front portion of the bristle carrier and being directed towards the centre axis of the grip over a region of less than half the length of the bristle carrier.

2. Atoothbrush as claimed in claim 1, compris ing a grip depression in the transition region between the grip and the bristle carrier, the grip depression extending from the grip over the entirety of the bend region, into the bristle carrier.

3. Atoothbrush as claimed in claim 2, wherein the grip depression extends about 20 mm into the grip and about 25 mm into the bristle carrier.

4. A toothbrush as claimed in claim 1,2 or 3 wherein the grip has a length of about 120 mm to 140 mm and has at its thickest region a diameter of about 12 mm and at its rear end a diameter of less than 6 mm, preferably 3 mm.

5. A toothbrush as claimed in any one of claims 1 to 4, wherein that the grip is slightly eliptical in cross-section.

6. Atoothbrush as claimed in any one of claims 1 to 5, wherein the angle between the bristle carrier and the centre axis of the grip is about 30 .

7. A toothbrush as claimed in any one of claims 1 to 6, wherein the bristle carrier has a length of preferably 70 mm to 80 mm, and the bristle zone extends over a length of about 20 mm to 30 mm at the front end of the bristle carrier.

8. A toothbrush as claimed in any one of claims 1 to 7, wherein the surface of the bristle carrier having the bristle zone is made planar.

9. A toothbrush as claimed in any one of claims 1 to 7, wherein the surface of the bristle carrier having the bristle zone is made trough-like.

10. Atoothbrush as claimed in any one of claims 1 to 9, wherein the individual bristle groups in the bristle zone are spherically rounded at the upper ends.

11. Atoothbrush as claimed in any one of claims 1 to 10, wherein a taper extending from the greatest diameter of the grip in the direction towards the bristle carrier also extends into the bristle carrier and effects a lateral constriction of the bristle carrier between the bend region and the bristle zone.