Brushing – scrubbing – and general cleaning – Implements – Brush or broom
Reexamination Certificate
2001-12-19
2004-08-10
Spisich, Mark (Department: 1744)
Brushing, scrubbing, and general cleaning
Implements
Brush or broom
C300S021000, C428S373000, C428S374000, C428S397000
Reexamination Certificate
active
06772467
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns a bristle for brushware or brushes, which is produced by cutting an extruded monofilament to length, and which tapers towards its useful end in a point-like manner, which is made from at least two co-extruded plastic components and has a shaft made from a soft elastic plastic and a core made from a flexible plastic which is harder than that of the shaft, wherein the core projects past the jacket at the use sided end to form a pointed tip. The invention also concerns a method for the manufacture of such bristles and a brush having such bristles.
The effectivity of a tooth brush for cleaning teeth and for tooth care depends mainly on the structure and function of the bristles in addition to the duration of the cleaning time. In the development of tooth brushes, the bristle material, bristle geometry, and the combination of the bristles within the bristle stock are therefore very important. The bristle stock or the bristles forming same must fulfil several functions in tooth care. They must reach the spherical lateral surfaces on the inner and outer sides of the teeth having largely varying curvatures and the useful end of the bristle and/or bristle jacket must work sufficiently effectively. Moreover, at least individual bristles of the bristle stock should penetrate into the interdental spaces from the inner and outer side of the teeth and the bristles should also exert a massaging action on the gum and, in particular, on the gum edges. Cleaning of the teeth and of the interdental spaces should, in conjunction with the dentifrice used, not only prevent plaque build-up but also remove existing plaque to prevent caries.
Dental tests have shown that in countries where caries prophylaxis is practiced, caries is rarely found on free and substantially flat tooth surfaces because these surfaces are easy to reach and clean with conventional dental hygiene means, such as tooth cleaning means, i.e. tooth brushes, dental floss etc. Moreover, prophylactic dentifrices which contain e.g. fluorides, can easily reach and treat these surfaces.
Recent studies have shown that approximately 80% of caries originates in the so-called dental fissures most of which are located on the chewing surfaces of the molars and premolars, which are therefore more prone to caries and to larger cavities. These gap-like fissures of very narrow cross-sections are, in and of themselves, an ecosystem which are difficult or impossible to reach with conventional tooth brushes and which foster undisturbed development of caries-generating plaque. Nor do dentifrices reach these locations to a sufficient degree. Additionally, the enamel at the bottom of the fissures is very thin and contains few minerals which even enhances caries formation at these locations.
Modern dental medicine classifies such fissures according to their geometrical shape into U- V- and I-shaped fissures. These represent approximately 93% of the fissures examined. So-called ampoule-shaped fissures have a considerably reduced occurrence of approximately 7%. These fissures narrow like a funnel to a narrowest location and then widen again like a sack. Additionally, all fissures are curved in their longitudinal extension and the funnel axis is often tilted or curved. Cleaning of these fissures would require extremely thin bristles which would deflect under the smallest loads due to their insufficient bending strength. Fine thin bristles or bristles having finely drawn ends are also desired in other fields, e.g. cosmetic brushes or brushware.
DE 90 12 603 U proposes conification of the bristle ends and at least partially providing the bristle stock of a tooth brush with such bristles to be able to also reach, in particular, the interdental spaces and highly rugged surface structures. The same purpose is fulfilled by a two component bristle (GB 2 325 401 A) having the pre-characterizing features of claim
1
. It is made from a shaft of soft elastic plastic e.g. nylon and a core which is harder than the shaft e.g. polyester, so that the conically tapered tip is substantially formed by the harder core. Another two component bristle (WO97/25 902A) has a core made from a plurality of monofilaments projecting past a closed jacket.
No concically tapered tip is envisioned nor would one be possible.
In a known tooth brush having a similar bristle design (EP 0 596 633), the main task is to achieve an improved flexibility in the region of the bristle ends with densely packed bristles and corresponding stability of the bundle, in order to, in particular, guarantee cleaning in the region of the gingival border without injuring the gingiva. Moreover, bristles are known (WO99/24649) which are separated at their ends into flags thereby mainly producing intensification of the bristle action due to multiplication of the bristle ends and action of the individual bristles over a larger surface region due to the flags.
Bristle tips have also been conventionally shaped by inserting them into a solvent—as in dip varnishing—and slowly removing them thereby dissolving the plastic material of the bristle. The bristle end remains in the solvent bath for the longest period of time to thereby form bristles with pointed ends. The method is expensive, environmentally harmful, and the formation of the tip cannot be exactly controlled such that each bristle has a different geometrical shape at the end and therefore a different bending and wear behavior.
Pulsed extrusion of monofilaments is also known to obtain a monofilament with varying diameter. The monofilament is cut in the region of the constriction to obtain bristles having tapered ends. Pulsed extrusion cannot be carried out at the large frequencies which would be required for the short bristle lengths of many applications, thereby producing a substantial amount of waste. Moreover, the ends would have irregular shapes.
It is therefore the underlying purpose of the invention to introduce a bristle with tapering bristle end corresponding to GB 2 325 401A which has sufficient bending strength and simultaneously good action of the bristle end. The bristle should furthermore be designed such that it can be produced with reproducible properties.
SUMMARY OF THE INVENTION
A bristle of this type is characterized in accordance with the invention in that the soft elastic shaft is additionally surrounded by a jacket made from a plastic which stiffens the shaft.
The inventive bristle has a distinct tapering which permits penetration of the end into narrow gaps, e.g. into the fissures of teeth down to the fissure bottom and permits action on the fissure wall and fissure bottom by elastic deflection. The bristle core thereby provides sufficient bending strength and at the same time good elasticity. The soft, preferably rubber-elastic shaft has similar effects as an eraser due to its higher coefficient of friction. It achieves a more uniform cleaning action since the soft material adjusts well to uneven surfaces.
The degree and length of the tapering are matched such that the bristle end does not deflect, and thereby become ineffective, under small loads. The tapering bristle end is guided by the bristle shaft such that it can penetrate into narrow gaps, e.g. fissures, without premature bending of the bristle itself. The inventive bristle permits very precise application of media, e.g. cosmetics, lip gloss, eye liner etc.
The plastic materials of the core and of the shaft can be mainly selected with regard to their intended function, whereas the bristle jacket provides the required bending strength. When the bristle is bent, the jacket can effect additional cleaning or polishing.
As mentioned above, the shaft is preferably made from a rubber-elastic plastic material, in particular from an elastomer.
In a further preferred embodiment, the shaft and/or jacket extend conically towards the tip of the core, wherein the conical angle defines the bending behavior of the bristle end.
In a further advantageous embodiment, the core also tapers conically such that the conical length defines its bending behav
Coronet-Werkc GmbH
Spisich Mark
Vincent Paul
LandOfFree
Brush bristle, method of making same and brush comprising... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Brush bristle, method of making same and brush comprising..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Brush bristle, method of making same and brush comprising... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3326382