Brushing – scrubbing – and general cleaning – Implements – Brush or broom
Reexamination Certificate
1999-11-29
2001-02-13
Till, Terrence R. (Department: 1744)
Brushing, scrubbing, and general cleaning
Implements
Brush or broom
C015S172000
Reexamination Certificate
active
06185779
ABSTRACT:
BACKGROUND OF THE INVENTION
Generally toothbrushes comprise a plastics material handle with a plastics material head adjoining the handle at a base end of the head, generally via a neck region, the head and handle being disposed along a longitudinal toothbrush axis, the head having bristles extending from a bristle face of the head which is an opposite head surface to a back face of the head. The direction between the bristle face and the back face being is defined as the thickness of the head. Bristles are generally distributed in bristle tufts mounted in socket holes in the bristle face, or may be fused into the head material.
Toothbrushes having a flexibly linked region in their head are known. For example WO 92/17093 discloses a toothbrush in which the head is divided into two or more segments which are flexibly and resiliently linked to each other and/or to the handle of the toothbrush. A particular form of the toothbrush of WO 92/17093 has a head which has grooves in the back face of the head, these grooves being filled with an elastomer material to modulate the flexibility of the head. The embodiments disclosed in WO 92/17093 have their grooves distributed in a generally uniform distribution over the reverse face of the head, or around the longitudinal mid point of the head, so as to enable the whole head to accommodate itself to the curved shape of the teeth. WO 96/02165 discloses toothbrushes with flexible heads similar in construction to those of WO 92/17093, and having a generally concave profile of bristle ends. DE-G 87 05 474.4 discloses a toothbrush in which the tip region of the head is hinged to a base region of the head and an operating button on the handle allows the tip region to fold relative to the base region. WO 97/24048 discloses a toothbrush in which the head is divided into two portions, having a flexible link about half way along the head.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a toothbrush with a flexible head in which the flexibility of the head is improved and ideally optimised.
According to a first aspect of this invention a toothbrush comprises a plastics material handle with a plastics material head adjoining the handle at a base end of the head, the head and handle being disposed along a longitudinal toothbrush axis, the head having bristles extending from a bristle face of the head and having an opposite back face, the head comprising at least two adjacent segments integrally linked by a flexible link of the plastics material of the head, a first surface of the link being in the same surface as either the bristle face or the back face of the head, characterised in that the minimum thickness of the link is between 0.2 and 2.0 mm.
The term “thickness” as used herein refers to the dimension measured in the direction between the bristle face and the opposite back face.
Preferably the minimum thickness of the link is between 0.5 and 1.0 mm, most suitably between 0.2 and 0.5 mm.
Preferably the minimum length of the link between adjacent linked segments is at most 0.4 mm.
Preferably the minimum thickness of the link is 0.2 to 0.3 mm, and the minimum length of the link between adjacent linked segments is at most 0.3 mm, desirably 0.2 mm.
In one embodiment of this first aspect of the invention the link is in the form of a strip of the plastics material having a second surface opposite to and substantially parallel to the said first surface.
The link is preferably linear between the linked segments, and may suitably also be linear oriented across the longitudinal axis of the head, or parallel to the longitudinal axis of the head. By “linear” is meant that the link is constructed to flex along a fold axis, and in a “linear” link the fold axis follows a substantially straight line. Alternatively the link may follow a curved, chevron or zig-zag linear path as seen in plan view onto the bristle face or back face of the head.
According to a second aspect of this invention a toothbrush comprises a plastics material handle with a plastics material head adjoining the handle at a base end of the head, the head and handle being disposed along a longitudinal toothbrush axis, the head having bristles extending from a bristle face of the head, and an opposite back face, the head comprising at least two adjacent segments integrally linked by a flexible link of the plastics material of the head, a first surface of the link being in the same surface as either the bristle face or the back face of the head, characterised in that the minimum thickness of the link is between 0.2 and 0.5 mm, and the link has a second surface opposite to the first surface, the second surface being a cylindrically or conoidally concave surface having a radius of curvature of between 0.1 and 2.0 mm, the radius being aligned in the direction generally perpendicular to the linked direction.
Preferably the minimum thickness of the link is 0.2 to 0.3 mm, and the radius of curvature is 0.3-1.4 mm. The concave surface is preferably a cylindrically concave surface.
The link is preferably linear between the linked segments, and may suitably be linear oriented across the longitudinal axis of the head, or parallel to the longitudinal axis of the head. Alternatively the link may follow a curved, chevron or zig-zag linear path as seen in plan view onto the bristle face or back face of the head.
In these two aspects of the invention, if the first surface is the same surface as the bristle face and the toothbrush head has bristle tufts mounted in socket holes in the bristle face, the minimum distance between the edges of adjacent socket holes is preferably no less than 0.45 mm, particularly no less than 0.55 mm.
According to a third aspect of this invention a toothbrush comprises a plastics material handle with a plastics material head adjoining the handle at a base end of the head, the head and handle being disposed along a longitudinal toothbrush axis, the head having bristles extending from a bristle face of the head, and an opposite back face of the head, the head comprising at least two adjacent segments integrally linked by a flexible link of the plastics material of the head, the link being situated intermediate between the bristle face and the back face of the head, characterised in that the maximum thickness of the link is between 0.2 and 3.0 mm.
Preferably the length of the link between adjacent linked segments is 1.0 to 2.5 mm, suitably 1.0 to 1.5 mm.
Preferably the maximum thickness of the link is between 0.2 and 0.4 mm, and the length of the link between adjacent linked segments is 1.0 to 2.0 mm.
In one embodiment of this third aspect of the invention the link is in the form of a strip of the plastics material having a first surface facing in the direction of the bristle face, and an opposite second surface facing in the direction of the back face, both the said first and second surfaces being substantially parallel to the bristle face of the head.
The link is preferably linear between the linked segments, and may suitably be linear oriented across the longitudinal axis of the head, or parallel to the longitudinal axis of the head. Alternatively the link may follow a curved, chevron or zig-zag linear path as seen in plan view onto the bristle face or back face of the head.
The link of this third aspect may be nearer to either the bristle face or the opposite face of the toothbrush, for example nearer to the bristle face.
In all of the above aspects of the invention the link may link segments which are sequentially longitudinally arranged along the longitudinal direction of the toothbrush head. In such a construction the link will preferably extend substantially widthways across the head, i.e with a fold axis across the head. Such a link may extend across the whole width of the head or partly across the width of the head, e.g there may be apertures in the head material between links.
For example the link may be a link which links longitudinally adjacent plastics material segments of the toothbrush head, and being in the form of a thin integral strip of plastics m
SmithKline Beecham Consumer Healthcare GmbH
Till Terrence R.
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