Patent Application
20120233798
This invention relates generally to power skin brush appliances, and more specifically concerns the brushhead portion of the appliance.
Power skin care brushes, such as those useful for cleansing of the facial region, are typically driven directly, such as by a drive shaft or shafts, gears and a motor. The skin brush typically includes a single brushhead, with a plurality of bristle/filament tufts, which move in unison. Some brushheads rotate (360°) in one direction continuously, while others oscillate through a selected angle. The higher frequency skin brushes are often referred to as sonic or sonic frequency brushes. Typically, the frequency range of such brushes is 120-300 Hz, usually producing some slight bristle tip flexing or whipping in addition to oscillation of the bristles. Such separate bristle tip movement usually does not occur in the lower speed scrub-type brushes. An example of such a sonic skin brush appliance and a brushhead is described in U.S. Pat. No. 7,320,691, which is owned by the assignee of the present invention, the contents of which are hereby incorporated by reference.
In some cases, the brushhead and drive system are configured so that portions of the bristle field of the brushhead move in different directions or move out-of-phase with the other portions. Such a particular movement may have advantages in facial cleaning, including the possibility of producing better cleansing with less discomfort. An appliance for producing such action is shown in U.S. Pat. No. 6,032,313. The brushhead assembly includes several concentric brush field portions, which are independently driven by separate mechanical means. However, not only is this a complicated drive structure, but it is not particularly suitable for the sonic speed appliances, because of noise and wear.
It remains desirable that a brushhead arrangement provide out-of-phase and/or counter-rotation action between different groups of bristle tufts but driven by a single drive mechanism.
Accordingly, the brushhead for use in a power skin brush appliance which includes a drive system having a single drive member, comprising: a base assembly mountable to the drive system having a moving portion which in operation oscillates back and forth through a selected angle and with a selected frequency in response to the drive system; and at least first and second concentric annular oscillating filament tuft groups mounted on the moving portion of the base assembly, wherein the first and second oscillating filament tuft groups each comprise at least one ring of filament tufts, the filament tufts in the first and second oscillating filament tuft groups, respectively, having a physical characteristic which differs sufficiently to produce a differential stiffness between the filaments comprising the first and second oscillating filament tuft groups to produce an out-of-phase motion of the tips thereof when wet.
Brushhead 14 in a preferred embodiment includes two fixed annular rings 42, 44, (
The brushhead also includes three oscillating tuft ring groups, the oscillating tuft ring groups being concentric, each comprising two individual complete annular rings of filament tufts. These include a first oscillating tuft ring group 47, a second oscillating tuft ring group 49 and a third tuft ring group 51. The first oscillating tuft ring group 47, also referred to as an outer oscillating tuft ring group, has a midpoint diameter of approximately 0.5 inches, between the two annular rings 52, 54 of filaments tufts which comprise the first oscillating tuft ring group. The outer oscillating tuft ring group has individual tufts with filaments with a diameter of approximately 3 mils. Each annular ring has approximately 24 tufts, and a total of 148-160 filaments. The filament diameter (3 mils) in the outer oscillating tuft ring group provides a relatively soft, gentle feel to the skin.
The second oscillating tuft ring group 49, also referred to as the middle oscillating tuft ring group, also comprises two concentric annular rings 58 and 60 of filament tufts. The filaments in the middle oscillating tuft ring group in the embodiment shown have a diameter of approximately 4 mils. The midpoint diameter of the middle oscillating tuft ring group is approximately 0.35 inches. Each annular tuft ring comprises 14 tufts and 85-95 filaments in the embodiment shown.
The third oscillating tuft ring group 51, also referred to as the inner oscillating tuft ring group, comprises two concentric annular tuft rings 68 and 70, with the individual filaments having a diameter of approximately 5 mils. The midpoint diameter of the inner oscillating tuft ring group in the embodiment shown is approximately 0.196 inches. Each annular ring comprises approximately 10 tufts and 50-60 filaments in the embodiment shown.
The inner oscillating tuft ring group filaments, being stiffer than the filaments in the other oscillating tuft ring groups, helps to provide an effective cleaning result. In the embodiment shown, the filament material is DuPont Hytrel® supersoft (polyester), with the filaments having a length of 0.375 mm, although this can be varied. For instance, a length of 0.325 mm also provides desired action.
The arrangement, configuration and structure of the outer, middle and inner oscillating tuft ring groups, respectively, is such as to provide a differential stiffness between the tufts in one oscillating tuft ring group relative to the tufts in one or both of the other oscillating tuft ring groups. The difference in tuft and filament stiffness is sufficient so as to result in an out-of-phase movement and in some cases a counter-rotation of one oscillating tuft ring group relative to the other oscillating tuft ring groups. For the embodiment described above, with the three different diameters of the filaments, with the above material, there is close to a counter-rotation between the filaments, in particular the tips of the filaments, when wet, in the inner oscillating tuft ring group relative to the middle and outer oscillating tuft ring groups. The outer and middle oscillating tuft ring groups are somewhat out-of-phase relative to each but only a relatively small amount, typically 30°-40° or so. In general, however, it is sufficient that there be a stiffness differential between the filaments in the respective oscillating tuft ring groups, due to difference in configuration, dimensions or material that there results an out-of-phase relationship between the tips of the filaments in a wet condition so that there be a relative (out-of-phase) tip displacement of 0.06 inches, resulting in a lateral force of 0.6 grams against the skin. One advantage of the out-of-phase arrangement to produce the desired tip displacement compared to other brushes having similar tip displacement in operation is more even cleansing over the entire surface of the brush by improvement of the action of the inner oscillating tuft group. It also results in better, more effective cleansing of the skin pores due to the smaller diameter of the filaments in the outer oscillating tuft group. The shear force between adjacent rows of filaments (bristles) is also enhanced by the out-of-phase action of the filament tips.
In the embodiment shown, the out-of-phase action of one or more of the oscillating tuft groups relative to the other oscillating tuft groups is at least at 15°, and preferably at least 50-60° to provide the desired cleaning effect, while maintaining comfort.
With the different diameters of the filaments in the oscillating three tuft ring groups, the wet tips of the filaments in the middle and outer tuft ring groups are out-of-phase with each other by perhaps 30°-40°, as shown by the 80 and 82 diagrams, while the tips of the wet filaments in the inner oscillating tuft ring group are sufficiently out-of-phase with the middle and outer ring group filaments that there is basically a counter oscillation, as shown at 84 in the diagram. Other out-of-phase relationships can be obtained by varying the diameter of the filaments somewhat differently but it is important that there be an out-of-phase relationship of at least 15° to produce the desired effects.
In addition to the differences in diameter and bristle count per tuft which account for the necessary differential stiffness between the filaments to produce the required out-of-phase movement of the filament tips, other physical characteristics of the filaments can be varied to produce the necessary differential stiffness. These include the material of the filaments and the individual length of the filaments. The differences must be sufficient, however, to provide at least a 15° out-of-phase relationship between one of the oscillating tuft ring groups and at least one of the other oscillating tuft ring groups to produce effective results. As one example, the filaments in the three oscillating tuft ring groups, respectively, could comprise solid, round (cross-section) nylon material (stiffest); solid, round polyester material; and hollow, round polyester material (softest) to produce the desired out-of-phase movement of tips of the bristles when wet.
Another variation concerns the length of the individual filaments. Since it is desired that the tips of the bristles be in substantially the same plane, the length of the individual bristles is achieved by varying the configuration of the base assembly. For instance, in one arrangement, the base element has a convex configuration, as shown in
As a further variation, it should be understood that, while in the preferred embodiment, there are three oscillating tuft ring groups, there could be two oscillating tuft ring groups or more than three, for instance, four or even six tuft ring groups. Still further, while the arrangement shown uses two individual tuft rings comprising each oscillating tuft ring group, as well as the fixed tuft ring group, it is possible to use a single tuft ring in one or more of the tuft ring groups, or more than two in other cases. Again, the arrangement must be such as to have a sufficient differential in stiffness between the filaments in the oscillating tuft ring groups so as to produce an out-of-phase movement between the tips of the filaments (when wet) comprising each tuft ring group. In some cases, the out-of-phase relationship is sufficient to produce a counter-rotation between the filaments in one oscillating tuft ring group and the filaments in the other oscillating tuft ring groups.
While the arrangement of
Hence, a new brushhead arrangement has been disclosed utilizing a plurality of concentric oscillating tuft ring groups, with the individual tufts having filaments constructed or configured so as to provide a differential stiffness between the tufts in the respective ring groups producing an out-of-phase and even counter-rotation effect of the tips of the bristles when wet, resulting in increased effectiveness of the brushhead while producing a gentle, comfortable feel for facial cleansing.
Although a preferred embodiment of the invention has been disclosed for purposes of illustration, it should be understood that various changes, modifications and substitutions may be incorporated in the embodiment without departing from the spirit of the invention, which is defined by the claims which follow.
