TOOTHBRUSH BRUSHHEAD FOR A POWER TOOTHBRUSH WITH ANGLED BRISTLES
The brushhead, which has a rotating action, includes a bristle plate and three separate sets of bristle tufts. A first set of bristle tufts extends longitudinally down the approximate center of the brushhead and is arranged to extend vertically from the base plate. The second and third sets of bristle tufts are arranged on opposing sides of the first set of bristle tufts, with the second and third sets of bristle tufts being arranged at an angle outwardly, in opposing directions, from the first set of bristle tufts, the angle being in the range of 5°-45°. The length of all the bristle tufts is established so that the tips of the bristles in the first, second and third sets of bristle tufts form a shallow arc.
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This invention relates generally to brushheads for toothbrushes, and more specifically concerns a brushhead with a particular bristle arrangement on the brushhead.
Certain power toothbrushes, for example, sonic (acoustic) energy toothbrushes such as shown and described in U.S. Pat. No. 5,378,153, which is owned by the assignee of the present invention, provide a selected amount of acoustic energy to the teeth for cleaning, by bristle-fluid interaction, in addition to scrubbing action by the tips of the bristles being in direct physical contact with the teeth. The acoustic energy provided to the teeth is particularly effective in cleaning hard-to-reach places, such as between the teeth and into the gingival areas. Acoustic energy thus is desirable for overall effective teeth cleaning. Increasing the applied acoustic energy, which increases the cleaning effect, can be accomplished in one way by increasing the speed of the bristles. However, there are significant limitations on increasing bristle speed, because as bristle speed increases, so does discomfort to the user and also abrasion of the teeth and/or the gums.
It is thus desirable to increase the bristle speed, in order to increase acoustic energy cleaning, without correspondingly increasing the discomfort to the user or abrasion to the teeth and/or gums. This is accomplished by the particular bristle arrangements shown and described herein.
Accordingly, the present invention comprises a brushhead for a power toothbrush in which the brushhead is driven in a side-to-side motion, comprising: a brushhead base plate; a plurality of lateral rows of bristle tufts, each row comprising: a first set of bristle tufts set into the base plate substantially vertically; a second set of bristle tufts set into the base plate extending along one side of the first set of bristle tufts and angled outwardly therefrom at an angle within the range of 5°-15°; and a third set of bristle tufts set into the base plate extending along the opposing side of the first set of bristle tufts and angled outwardly therefrom within the range of 5°-15°, wherein the bristle tufts in the second and third sets are set into the base plate a horizontal distance “r” in the range of 1.2 mm to 4 mm from the center of rotation of the brushhead.
The first set of bristle tufts 40 (two tufts are shown) extend vertically upwards from bristle plate 32, approximately 1.2 cm. high. Each bristle tuft contains approximately 10-50 bristles. Typically, the bristles will be made of nylon, and will be in the range of 0.004-0.009 inches in diameter.
The second and third sets of bristle tufts (38 and 42, with one tuft shown in each set) are located on opposite sides of the first, mid-position bristle tuft set 40. The second and third sets of bristle tufts are substantially identical to each other and are similar to the bristles in the first set, being also made of nylon and having approximately the same diameter as the first set. The second and third sets of bristle tufts, however, are oriented at an angle to the vertical, as shown in
The length of the bristles in the second and third sets of bristles is such that when the brushhead is at rest, as shown in
The angular difference between the action angle and the bristle angle (the “delta” angle ABE) has a direct and significant influence on the performance of the toothbrush. In a normal bristle configuration there is the potential for the bristles to bend and/or be dragged across a tooth surface, as opposed to a “dig” and/or “buckle” action against the surface. The most efficiently performing bristle arrangement will have a hypothetical delta angle of 0°; it has been established in this present invention that the upper limit of an efficiently performing bristle arrangement is with a delta angle of 21°. A practical and preferred range for the delta angle is 17-21°.
A of the bristle plate.
Considering adjacent tufts of bristles (as viewed in the plane perpendicular to the axis of rotation), such as bristle tufts 72 and 74, as the bristles move against the teeth, differences in action length between two adjacent tufts have to be accommodated as the longer tuft comes into position by flexing of tufts or moving of the brush by the user (or in reaction to the impact of the longer action length tuft in a space previously accommodating the smaller one). The flexing or impact will be detrimental to the experience of the user as well as brush performance (energy is wasted). The most efficiently performing brush will have a zero change in action length from adjacent tuft to adjacent tuft. It has been established by the inventors herein that the most efficiently performing toothbrush will have an upper limit of 1.25 mm in the change of action length from bristle tuft to adjacent bristle tuft.
The angled bristle arrangement has an important cleansing effect during operation of the toothbrush. It provides users an enhanced brushing experience. The amplitude of the brush motion, as well as the frequency of the motion, can be increased, to increase the speed of the bristles, which improves cleaning, without causing discomfort to the user or abrasion to the user's mouth/gum tissues. The end loading of the bristles which causes the discomfort is a function of the impact angle created by the angled bristles. When the bristles are angled away from the direction of motion, but offset from the center of rotation of the brushhead, the end loading of the bristle tips is decreased to some extent, resulting in weaker forces to the teeth. This weaker loading provides less mechanical cleaning action on the teeth, but does decrease the acoustic energy transfer to the teeth.
The acoustic energy transfer can now be increased by increasing the speed and/or amplitude of the bristle motion, without discomfort, which is caused by the mechanical scrubbing action. As an example, the amplitude of the brush movement can be increased from approximately 13° to 16°, an increase in the range of 15-30 percent. At the same time; or independently, the speed of the brushhead can be increased, by approximately 15-30 percent. Both the amplitude and speed of the brushhead can be increased if desired.
Hence, a new bristle arrangement has been disclosed, using a radially angled bristle arrangement, which permits an increase of velocity or amplitude of the rotational brushhead (with bristles) motion, which in turn results in enhanced cleaning, without discomfort and/or abrasion to the tissues.
Although a preferred embodiment of the invention has been disclosed for purpose of illustration, it should be understood that various changes, modifications and substitutions can be incorporated in the embodiment without departing from the spirit of the invention which is defined by the claims which follow:
Claims
1. A brushhead for a power toothbrush in which the brushhead is driven in a side-to-side motion, comprising:
- a brushhead base plate;
- a plurality of lateral rows of bristle tufts, each row comprising:
- a first set of bristle tufts set into the base plate substantially vertically;
- a second set of bristle tufts set into the base plate extending along one side of the first set of bristle tufts and angled outwardly therefrom at an angle within the range of 5°-15°; and
- a third set of bristle tufts set into the base plate extending along the opposing side of the first set of bristle tufts and angled outwardly therefrom within the range of 5°-15°, wherein the bristle tufts in the second and third sets are set into the base plate a horizontal distance “r” in the range of 1.2 mm to 4 mm from the center of rotation of the brushhead.
2. The bristle configuration of claim 1, wherein the angle of the bristles is approximately 10°.
3. The bristle configuration of claim 1, wherein the length of the bristles in the first, second and third sets of bristles is such that the tips of the bristles from a shallow arc centered on the axis of rotation of the brushhead base plate.
4. A brushhead for a power toothbrush in which the brushhead is driven in a side-to-side motion, comprising:
- a brushhead base plate;
- a plurality of lateral rows of bristle tufts, each row comprising:
- a first set of bristle tufts set into the base plate substantially vertically, arranged in the longitudinal direction of the base plate;
- a second set of bristle tufts set into the base plate extending along one side of the first set of bristle tufts and angled outwardly therefrom; and
- a third set of bristle tufts set into the base plate extending along the opposing side of the first set of bristle tufts and angled outwardly therefrom, wherein there is a difference in length between the bristles in adjacent tufts of bristle in the second and third sets of bristles in the range of 0-1.25 mm and an angular difference between the action angle and the bristle angle of the bristle tufts in the range of 0°-21°.
5. The brushhead of claim 4, wherein the second and third sets of bristle tufts are arranged on the bristle plate to be offset from the center of rotation of the bristle plate.
6. The brushhead of claim 4, wherein the amplitude of movement of the brushhead and the speed of the brushhead can be increased by approximately 15-30 percent without increasing discomfort to the users.
7. The brushhead of claim 4, wherein the angular difference is within the range of 17°-21°.
Type: Application
Filed: Dec 21, 2005
Publication Date: Mar 11, 2010
Applicant: KONINKLIJKE PHILIPS ELECTRONICS N.V. (EINDHOVEN)
Inventors: Joseph W. Grez (North Bend, WA), William Bryant (North Bend, WA), Scott Hall (Issaquah, WA)
Application Number: 11/722,488