Brushing – scrubbing – and general cleaning – Implements – Brush or broom
Reexamination Certificate
1998-08-20
2002-06-25
Till, Terrence R. (Department: 1744)
Brushing, scrubbing, and general cleaning
Implements
Brush or broom
C015S172000
Reexamination Certificate
active
06408476
ABSTRACT:
SUMMARY OF THE INVENTION
The present invention relates to a toothbrush, more particularly to a toothbrush with a comprising regions of elastomer in both the head and the handle wherein one or more elastomer supply channels connect the regions so that they can all be filled with elastomer from a single injection point.
BACKGROUND OF THE INVENTION
The configuration of human teeth requires that the ideal bristle contour for toothbrushes for brushing the buccal or outside surfaces of teeth be concave and that the ideal bristle contour for brushing the lingual or inside surfaces of teeth be convex. Most brushes have a single piece head which is of comparable thickness to the handle and which is relatively rigid and of a fixed curvature or configuration.
A further drawback of conventional brushes is that pressing the brush sufficiently hard against the teeth to get good cleaning risks damaging or discomforting the softer, adjacent gums. To a certain extent this can be solved by modifying the configuration of the brush, or by varying bristle hardness or length, though again, a single configuration cannot be optimum for all circumstances.
Some brushes mat, however, incorporate a means for allowing the head to flex relative to the handle, as described for example in EP-A-371,293. Even so, such brushes have limited effectiveness. Other brushes are known which are adjustable into several different but fixed configurations. Adjustable toothbrushes are often difficult to manipulate and may be unreliable.
WO 92/17093 discloses a toothbrush having a handle and at one end thereof a bristle-bearing head, wherein the head is in the form of two or more segments flexibly and resiliently linked tan each other and/or to the handle, one or more of the segments being bristle bearing. In one embodiment this is achieved by the use of transverse, and optionally longitudinal, grooves on the opposite face of the head to the bristles. The grooves can be wholly or partially filled with an elastomer.
Co-filed application WO 92/17092 further discloses a toothbrush having a handle and at one end thereof a bristle-bearing head which is flexibly and resiliently lid to an extended portion of the handle. The space between the head and the handle may be filled with an elastomer. The applicant markets a brush called the ‘Schwingkopf’ under the name ‘Dr. Best’ which contains some of the features disclosed in WO 92/17092. The brush has an elastomeric handle grip and an elastomer filled groove connecting the grip to an elastomer filled region in the neck of the brush. However, the brush does not contain transverse grooves in the head.
It is well-known to provide elastomeric grips in the handles of toothbrushes. It is also known from the above-mentioned PCT applications to provide transverse grooves containing elastomer into a brush head. To the present applicant's knowledge however, it has not been disclosed how both these objects can be achieved using a conventional single-point, injection moulding process.
It has now been found that all of the elastomer filled areas of the brush can be filled by a single-point injection moulding process by providing one or more elastome supply channels which connect the grooves in the head to the grips in the handle.
It is accordingly an object of this invention to provide a toothbrush with a flexible head and handle grips which can be made by a simple injection moulding process.
It is yet a further object of this invention to provide a toothbrush which has good long-term durability.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided a toothbrush, comprising:
i) an elongated handle having distal and proximal ends and one or more elastomeric handle regions therein; and
ii) a resiliently flexible head attached to the proximal end of the handle, the head including a pair of opposing faces, one of the pair being a bristle-bearing face with bristles attached to and extending from the face, wherein at least one of the pair has one or more elastomer-containing, transverse grooves therein; and
iii) one or more elastomer supply channels extending between the elastomeric handle regions and the transverse grooves,
whereby at least one of the elastomeric handle regions and the transverse grooves can be filled with elastomer from a single injection point.
According to a second aspect of the invention there is provided a toothbrush, comprising:
i) an elongated handle having distal and proximal ends and one or more elastomeric handle regions therein; and
ii) a resiliently flexible head attached to the proximal end of the handle, the head including a pair of opposing faces, one of the pair being a bristle-bearing face with bristles attached to and extending from the face, wherein each of the pair has one or more elastomer-containing transverse grooves therein, the grooves dividing the head into segments which are flexibly connected by hinges, wherein each hinge is located between the opposing faces and at a distance of at least about 10% of the depth of the head from each of the faces, the hinges being less than the full width of the head; and
iii) one or more (elastomer supply channels extending between the elastomeric handle regions and the transverse grooves,
whereby at least one of the elastomeric handle regions and the transverse grooves can be filled with elastomer from a single injection point.
The toothbrush of this invention comprises a handle including elastomeric regions, which can be used to improve the user's grip on the handle, and a head which has transverse grooves, that allow the head to flex under the action of brushing and accommodate itself to, for example, the differing profiles of individual users' teeth. The head further includes elastomer contained within the grooves on at least one face. The elastomer improves the resilience of the head by acting like a spring, so that when a force applied to bend the head is removed, the head returns within a short period of time to its original configuration. The toothbrush further comprises one or more supply channels which connect the elastomeric regions in the handle to the transverse groove in the head enabling the elastomer in both the head grooves and handle regions to be supplied from a single elastomer injection point. The grooves divide the head into segments and define hinges which connect the segments. Preferably, there are transverse grooves on both of the opposing faces and the hinges are located between the faces so that they are subject to the minimum amount of tension or compression. In this case the hinges are preferably less than the full width of the head so that elastomer can flow from one face of the had to the opposing face. The interconnectivity of the elastomer containing parts enables all of them to be filled with elastomer using a single-point injection moulding process on conventional equipment.
DETAILED DESCRIPTION OF THE INVENTION
Handle
The toothbrush of this invention comprises an elongated handle having distal and proximal ends and one or more elastomeric handle regions therein. The handle can be of shape and external dimension suitable for toothbrushes. The elastomeric regions in the handle are generally designed to act as hand or finger grips but they can be provided for solely aesthetic purposes, for example to give the brush a distinctive appearance. The elastomeric regions can be flush with the surface of the handle or raised or recessed from the handle surface. Preferably at least a part of one elastomeric region is raised for providing better grip. In general the elastomeric regions are provided by initially moulding the handle the handle to comprise voids which are then filled by the elastomer in a separate injection moulding step. The voids provide some physical entrapment of the elastomer, but preferably the elastomer is chosen so that it becomes bonded to the handle material through the injection moulding process. The voids can be arranged so that when filled with elastomer the various elastomer regions, at least when handle material is opaq
Clark Karen F.
Nichols Vanessa M.
The Procter & Gamble & Company
Till Terrence R.
Vago James C.
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