U.S. patent application number 09/730426 was filed with the patent office on 2001-04-26 for bristle sub-assemblies and method of making same.
Invention is credited to Chambers, Jeffrey Allen, Edwards, Mark Stephen.
Application Number | 20010000481 09/730426 |
Document ID | / |
Family ID | 22933521 |
Filed Date | 2001-04-26 |
United States Patent
Application |
20010000481 |
Kind Code |
A1 |
Edwards, Mark Stephen ; et
al. |
April 26, 2001 |
Bristle sub-assemblies and method of making same
Abstract
A bristle sub-assembly includes first and second base strings
and a plurality of polymeric monofilaments connected to and
extending between the first and second base strings. The polymeric
monofilaments form a first arched row when the first and second
base strings are brought together. Several types and configurations
of brushes are made using either arched bristles or combinations of
arched and straight bristles.
Inventors: |
Edwards, Mark Stephen;
(Hockessin, DE) ; Chambers, Jeffrey Allen;
(Hockessin, DE) |
Correspondence
Address: |
John A. Langworthy
E. I. du Pont de Nemours and Company
Legal-Patents
Wilmington
DE
19898
US
|
Family ID: |
22933521 |
Appl. No.: |
09/730426 |
Filed: |
December 5, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09730426 |
Dec 5, 2000 |
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09247093 |
Feb 9, 1999 |
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09247093 |
Feb 9, 1999 |
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09092092 |
Jun 5, 1998 |
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6096151 |
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Current U.S.
Class: |
428/92 ;
15/159.1; 15/167.1; 156/174; 156/427; 156/435; 156/580.1; 156/72;
156/73.1; 300/21 |
Current CPC
Class: |
B29C 65/08 20130101;
B29C 66/73921 20130101; A46B 9/04 20130101; Y10T 428/23957
20150401; Y10S 15/05 20130101; B29C 66/71 20130101; B29L 2031/42
20130101; B29C 66/69 20130101; A46B 3/00 20130101; B29C 66/7392
20130101; A46D 1/00 20130101; B29C 66/71 20130101; B29K 2077/10
20130101; B29C 66/71 20130101; B29K 2077/00 20130101; B29C 66/71
20130101; B29K 2075/00 20130101; B29C 66/71 20130101; B29K 2067/006
20130101; B29C 66/71 20130101; B29K 2067/00 20130101; B29C 66/71
20130101; B29K 2027/12 20130101; B29C 66/71 20130101; B29K 2027/08
20130101; B29C 66/71 20130101; B29K 2027/06 20130101; B29C 66/71
20130101; B29K 2025/08 20130101; B29C 66/71 20130101; B29K 2025/06
20130101; B29C 66/71 20130101; B29K 2025/04 20130101; B29C 66/71
20130101; B29K 2023/00 20130101 |
Class at
Publication: |
428/92 ; 15;
156/174; 156/73.1; 156/72; 156/435; 156/427; 156/580.1; 300/21;
15/159.1; 15/167.1 |
International
Class: |
B65H 081/00; A46B
009/04; A46B 015/00; A46D 001/00 |
Claims
What is claimed is:
1. A bristle sub-assembly comprising: first and second base
strings; and a plurality of monofilaments connected to and
extending between the first and second base strings, whereby the
monofilaments form a first arched row when the first and second
base strings are brought together.
2. A bristle sub-assembly according to claim 1, wherein at least
one of the base strings and the monofilaments are made of a
polymeric material.
3. A bristle sub-assembly according to claim 2, wherein the
polymeric material is a thermoplastic polymeric material.
4. A bristle sub-assembly according to claim 1, wherein at least
one of the base strings and the monofilaments are made of a
material selected from the group consisting of aliphatic
polyamides, aromatic polyamides, polyesters, polyolefins, styrenes,
polyvinylchloride (PVC), fluoropolymers, polyurethane,
polyvinylidene chloride, polystyrene and styrene copolymers, and
co-extrusions of at least one polymer.
5. A bristle sub-assembly according to claim 1, wherein at least
one of the base strings and the monofilaments are made of a nylon
material.
6. A bristle sub-assembly according to claim 5, wherein the nylon
material is selected from the group consisting of 4 nylon, 6 nylon,
11 nylon, 12 nylon, 6,6 nylon, 6,10 nylon, 6,12 nylon, 6,14 nylon,
10,10 nylon and 12,12 nylon and other nylon copolymers.
7. A bristle sub-assembly according to claim 1, wherein at least
one of the base strings and the monofilaments are made of
polybutylene terephthalate (PBT).
8. A bristle sub-assembly according to claim 1, wherein at least
one of the base strings is a monofilament made of thermoplastic
material having a diameter of 2-200 mils.
9. A bristle sub-assembly according to claim 1, wherein the base
string is a bundle of monofilaments, at least one of which is made
of a thermoplastic polymeric material.
10. A bristle sub-assembly according to claim 1, wherein the
monofilaments are heat fused to the base strings.
11. A bristle sub-assembly according to claim 1, wherein the mono
filaments are adhesively bonded to the base strings.
12. A bristle sub-assembly according to claim 1, wherein the
monofilaments are solvent bonded to the base strings.
13. A bristle sub-assembly according to claim 1, wherein the
monofilaments have a diameter between 2 and 200 mils.
14. A bristle sub-assembly according to claim 1, wherein the
monofilaments have varying diameters between 2 and 200 mils.
15. A bristle sub-assembly according to claim 1, wherein at least
one of the base strings and the monofilaments have substantially
circular cross-sectional shape.
16. A bristle sub-assembly according to claim 1, wherein at least
one of the base strings and the monofilaments have substantially
non-circular cross-sectional shape.
17. A bristle sub-assembly according to claim 1, further comprising
a third base string disposed between the first and second base
strings, whereby the mono filaments form the first arched row when
the first and third base strings are brought together, and a second
arched row when the second and third base strings are brought
together.
18. A brush assembly comprising: a brush body; and a first bristle
sub-assembly connected to the brush body, and including first and
second base strings and a plurality of monofilaments connected to
the first and second base strings, the monofilaments forming a
first arched row that extend upwardly from the brush body.
19. A brush assembly according to claim 18, wherein at least one of
the base strings and the monofilaments are made of polymeric
material.
20. A brush assembly according to claim 18, wherein at least one of
the base strings and the monofilaments are made of thermoplastic
material.
21. A brush assembly according to claim 18, wherein the first and
second base strings are each at least a single monofilament made of
a polymeric thermoplastic material.
22. A brush assembly according to claim 18, wherein at least one of
the base stings and the monofilaments are made of a material
selected from the group consisting of aliphatic polyamides,
aromatic polyamides, polyester, polyolefins, styrenes,
polyvinylchloride (PVC), fluoropolymers, polyurethane,
polyvinylidene chloride, polystyrene, and styrene copolymers and
co-extrusions of at least one polymer.
23. A brush assembly according to claim 18, wherein at least one of
the base strings and the monofilaments are made of a nylon
material.
24. A brush assembly according to claim 23, wherein the nylon
material is selected from the group consisting of 4 nylon, 6 nylon,
11 nylon, 12 nylon, 6,6 nylon, 6,10 nylon, 6,12 nylon, 6,14 nylon,
10,10 nylon and 12,12 nylon and other nylon co-polymers.
25. A brush assembly according to claim 18, wherein at least one of
the base strings and the monofilaments are made of polybutylene
teraphthalate (PBT).
26. A brush assembly according to claim 18, wherein the
monofilaments are heat fused to the first and second base
strings.
27. A brush assembly according to claim 18, wherein the
monofilaments are adhesively bonded to the first and second base
strings.
28. A brush assembly according to claim 18, wherein the
monofilaments are solvent bonded to the first and second base
strings.
29. A brush assembly according to claim 18, wherein the
monofilaments have a diameter between 2 and 200 mils.
30. A brush assembly according to claim 18, wherein the
monofilaments have diameters that vary between 2 and 200 mils.
31. A brush assembly according to claim 18, further comprising at
least a second bristle sub-assembly connected to the brush body,
and including at least third and fourth base strings and a
plurality of polymeric monofilaments connected to and extending
between the third and fourth base strings, the monofilaments
forming a second arched row that extend upwardly from the brush
body.
32. A brush assembly according to claim 31, wherein the first and
second arched rows are mounted longitudinally and concentrically on
the brush body.
33. A brush assembly according to claim 31, wherein the first and
second arched rows are mounted transversely on the brush body.
34. A brush assembly according to claim 18, further comprising at
least one row of straight monofilament bristles, each including a
plurality of monofilament bristles extending upwardly from a base
string.
Description
RELATED APPLICATIONS
1. This is a continuation-in-part of U.S. Ser. No. 09/092,092,
filed Jun. 5, 1998.
BACKGROUND OF THE INVENTION
2. The present invention relates generally to articles made of
polymeric monofilaments, and more particularly, to looped bristles,
methods for making looped bristles and bristle sub-assemblies, and
monofilament bristle sub-assemblies connected to brush bodies.
3. The aforementioned co-pending application describes a
manufacturing technique in which a base string is fed axially along
a mandrel while at the same time a monofilament is wrapped around
the mandrel, thereby producing a plurality of "wraps" which are
transported along the mandrel by the base string. The wraps are
then bonded to the base string using an ultrasonic welder, and
subsequently cut to thereby form an article having two rows of
monofilament segments connected to the base string.
4. This article, called a "bristle string," can then be cut to
lengths and used to make a variety of brushes or other products
requiring bristles. In one example, several rows of bristles are
formed in a toothbrush by mounting the bristle string segments in
the head portion of a toothbrush. Typically, the proximal ends of
the bristles are connected to the brush head and the distal ends
extend freely upwardly.
5. Brushes with looped bristles have been used in the past. For
example, U.S. Pat. No. 4,211,217 to Gueret describes a hair and
massage brush in which the bristles are bent to form loops which
are anchored in perforations formed in the brush head fusing the
ends together. As another example, U.S. Pat. No. 4,406,032 to
Diamant describes a toothbrush which includes a filament wrapped
around the head to form a plurality of circular loops.
6. U.S. Pat. No. 4,493,125 to Collis describes a toothbrush having
a combination of curved bristles and straight bristles. The curved
bristles were formed by having opposite ends of straight filaments
embedded in the head of the toothbrush in groups, thereby forming
loops. The loops are then cut axially to form two rows of curved
bristles. Other examples where looped bristles are used in a
toothbrush are shown in U.S. Pat. No. 4,030,845 to Deckert, U.S.
Pat. No. 2,599,191 to Meunier, and U.S. Pat. No. 4,438,541 to Jacob
et al.
7. While these show various forms of loop bristles, a need exists
for a looped bristle structure that is relatively easy to
manufacture and cost effective to produce.
SUMMARY OF THE INVENTION
8. An object of the present invention is to provide means to expand
brush design beyond the range possible with current tufting
techniques.
9. Another object of the present invention is to provide a bristle
sub-assembly for a brush in which individual filaments are
positionally fixed with respect to each other prior to connection
to a brush body.
10. Still another object of the present invention is to provide a
method of assembling brushes in which bristle sub-assemblies can be
permanently connected to the brush body or, alternatively,
detachably connected for subsequent replacement, thereby avoiding
wastefully discarding otherwise functional brush bodies.
11. Yet another object of the invention is to provide a brush that
has a combination of arched bristles, looped bristles and straight
bristles, whereby both types of bristles can be assembled without
using conventional tufting techniques.
12. These and other objects are met by providing a bristle
sub-assembly which includes two substantially parallel base strings
and a plurality of polymeric monofilaments connected transversely
between the two base strings. When the two base strings are
juxtaposed to each other, they form a single row of arched
monofilaments. The row of arched monofilaments can be sized to a
desired length by cutting the two base strings and then connecting
them to a brush head in desired patterns.
13. Other objects and features of the invention will become more
apparent from the following detailed description when taken in
conjunction with the illustrative embodiments in the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
14. FIG. 1 is a horizontal sectional view of an apparatus for
making bristle sub-assemblies according to a preferred embodiment
of the present invention, taken at an ultrasonic welding stage;
15. FIG. 2 is a horizontal sectional view of an apparatus for
making bristle sub-assemblies according to a preferred embodiment
of the present invention, taken at a cutting stage;
16. FIG. 3 is a plan view of a bristle sub-assembly made with the
apparatus of FIG. 1, prior to bending the monofilament segments
into arched formations;
17. FIG. 4 is an end view of a row of arched monofilaments made
from the bristle sub-assembly of FIG. 3;
18. FIG. 5 is a horizontal sectional view of an apparatus for
making bristle sub-assemblies according to another preferred
embodiment of the present invention, taken at a cutting stage;
19. FIG. 6 is an end view of a bristle string sub-assembly made by
the apparatus of FIG. 5:
20. FIG. 7 is an end view of the bristle string sub-assembly of
FIG. 6, bent to form an arch section;
21. FIG. 8 is a plan view of a bristle sub-assembly made according
to another embodiment of the present invention;
22. FIG. 9 is an end view of the bristle sub-assembly according to
claim 8, after forming a pair of arched segments;
23. FIG. 10 is a perspective view of a toothbrush made with the
arched bristles made according to the present invention;
24. FIG. 11 is a partial, longitudinal cross-sectional view of the
forward portion of the toothbrush of FIG. 10;
25. FIG. 12 is an end view of a brush head according to another
embodiment of the present invention, and having a row of arched
bristles and two flanking rows of straight bristles;
26. FIG. 13 is an end view of a brush head according to another
embodiment of the present invention, and having a first row of
arched bristles concentrically disposed with a second row of arched
bristles; and
27. FIG. 14 is an end view of a brush head according to another
embodiment of the present invention, and having a row of arched
bristles extending over three longitudinal rows of straight
bristles.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
28. Referring to FIGS. 1 and 2, a hollow, substantially rectangular
mandrel 10 has four beveled corners 12, 14, 16, and 18 which
include flat surfaces that are at 45.degree. angles to the
contiguous flat surfaces of the mandrel 10. Base strings 20, 22,
26, 28, 30, 32, 34 and 36, entering one axial end of the mandrel
10, pass downwardly through the interior of the mandrel 10. The
base strings are turned at the opposite end and guided for movement
in the opposite direction in pairs along respective corners of the
mandrel 10 as shown.
29. A monofilament 38 is wrapped around the mandrel 10 as the base
strings translate to thereby form a plurality of wraps that are in
contact with the base strings. The base strings move the wraps
under ultrasonic bonding horns 40, 42, 44 and 46, each of which is
juxtaposed a respective corner of the mandrel 10. The horns are
energized to thermally fuse the wraps of monofilament to the base
strings.
30. After bonding, the base strings further transport the
monofilament wraps, now connected to the base strings, to a cutting
station. As seen in FIG. 2, the cutting station includes a cutting
blade 48, 50, 52, and 54 disposed at respective corners to cut the
monofilament wraps between each pair of base strings to form four
separate bristle sub-assemblies. While each cutting blade is shown
to be rotatable about an axis illustrated in broken lines in FIG.
2, any suitable mechanical or wave energy cutting device can be
employed.
31. Referring to FIG. 3, one of the bristle sub-assemblies 56 is
shown with two base strings 22 and 26, disposed parallel to each
other, and the plurality of wraps bonded to the base strings at
substantially right angles to form a plurality of monofilament
segments 58. As seen in FIG. 4, as the parallel base strings 22 and
26 are moved towards each other, the monofilament segments 58 bend
to form an arched row 60 of monofilaments.
32. Other monofilament bristle sub-assemblies can be made by
varying the number of base strings and re-positioning the slitters.
For example, in FIG. 5 the mandrel 62 has a substantially square
cross-sectional shape, with base strings 64, 66, 68 and 70 disposed
respectively at each of the four corners of the mandrel 62. A
monofilament 72 is wrapped around the mandrel 62 and transported by
the base strings as before to form a plurality of wraps. After
passing under ultrasonic bonders (not shown) and thermally fused to
the base strings, the monofilament wraps are transported to a
cutting station which includes two cutting blades 74 and 76.
33. The cutting blades cut the monofilament wraps on opposite sides
of the mandrel 62 to form two nearly identical bristle string
sub-assemblies 78, of which one is shown in FIG. 6. The
sub-assembly 78 includes a plurality of monofilament segments 80
connecting to and extending between the two base strings 68 and 70,
and two rows of monofilament segments 82 and 84. As seen in FIG. 7,
when the base strings 68 and 70 are brought together in the
direction of the directional arrows, the monofilament segments 80
form an arch.
34. In another embodiment, seen in FIG. 8, the monofilament wraps
are cut to form a bristle string sub-assembly 86 in which the
monofilament segments 88 are connected to base strings 90, 92 and
94. As seen in FIG. 9, when the two outer base strings 90 and 94
are moved towards the middle base string 92, as illustrated by the
directional arrows, a pair of arched segments 96 and 98 are
formed.
35. The various bristle sub-assemblies described above can be used
in a variety of products, including brushes. FIG. 10 shows a
toothbrush 100 having a handle portion 102, a head portion 104, and
a bristle portion which includes straight rows 106, 108, 110, 112,
114 and 116 of monofilament bristles, which are alternatingly
disposed between arched rows 118, 120, 122, 124 and 126 of
monofilament bristles. The straight bristles can be made according
to the techniques described in co-pending application Ser. No.
09/092,092 entitled Method and Apparatus For Making Articles Having
Bristles, which is incorporated herein by reference. Alternatively,
the straight bristles can be made by using the techniques described
herein with respect to the embodiment of FIG. 7, whereby the
straight bristles are made from the straight segments 82 and
84.
36. The straight bristles and arched bristle sub-assemblies are
assembled with the head portion 104 by using the techniques
described in co-pending application Ser. No. 09/092,094 entitled
Monofilament Bristle Assemblies and Methods of Making Brushes Using
Same, which is incorporated herein by reference. For example, and
as seen in FIG. 11, the head portion 104 is provided with
transverse grooves which receive the single base strings of
straight rows 106 and 108 and the two base strings of arched rows
118 and 120. Alternatively, straight rows 106 and 108 can share
respective grooves with the corresponding base strings of arched
row 118 to form a more compact brush head. Upon placing the base
strings in the grooves, chemical, thermal or mechanical means are
used to seal the grooves and lock the base strings in place.
37. The bristle sub-assemblies described herein can be used to
construct brushes with a variety of bristle patterns and
combinations. FIG. 12, which is a front end view of a toothbrush
128, has two rows 130 and 132 of straight monofilament bristles
which flank a single row 134 of arched monofilament bristles. The
rows 130 and 132 extend to a height greater than the apex of the
row 134 of arched monofilaments. All three rows extend
longitudinally from the upper surface of a head portion 136 of the
toothbrush 128. Each of rows 130 and 132 have a base string mounted
in the head portion 136, while row 134 has two base strings mounted
in the head portion, one corresponding to each leg of the arched
monofilaments.
38. FIG. 13, also a front end view of a toothbrush 138, has two
rows 140 and 142 of arched monofilament bristles which are disposed
concentrically with respect to each other. Row 140 has an apex
greater than that of row 142, and the legs of row 140 are disposed
outside the legs of row 142. Both rows extend longitudinally from
the upper surface of a head portion 144 of the toothbrush 138. Each
of rows 140 and 142 have two base strings mounted in the head
portion 144.
39. FIG. 14, also a front end view of a toothbrush 146, has a row
148 of arched monofilament bristles which run longitudinally along
the brush head 150, and three rows 152, 154, and 156 of straight
bristles which likewise run longitudinally along the brush
head.
40. The various embodiments described herein can employ virtually
any combination of arched and straight bristle sub-assemblies, and
may further include the looped bristle sub-assemblies described in
U.S. Ser. No. 09/092,092.
41. An advantage to the present invention is that the bristle
sub-assemblies can be mixed and matched to create a variety of
desired arched and straight bristle combinations. For toothbrush
applications, the arched bristles have the additional advantage
that there are no distal ends to be treated, as is the case for
straight bristles.
42. The monofilaments used for both the straight and arched bristle
sub-assemblies are each a single filament, as opposed to a
"multi-filament," such as yarn, twine, etc., although the
monofilament may be a co-extrusion of one or more polymers to form
a coaxial structure. The monofilaments may be made of several
different materials, including aliphatic polyamides, aromatic
polyamides, polyesters, polyolefins, polystyrene, polyvinylchloride
(PVC), polyurethane, polyvinylidene chloride, fluoropolymers,
styrenes and styrene copolymers. A particularly suitable polymeric
material for toothbrush applications is 6,12 nylon; other nylons
may be used, including 4 nylon, 6 nylon, 11 nylon, 12 nylon, 6,6
nylon, 6,10 nylon, 6,14 nylon, 10,10 nylon and 12,12 nylon and
other nylon co-polymers. An example of a preferred polyester is
polybutylene terephthalate (PBT).
43. When the monofilaments are abutting as in FIG. 3, the
interconnection of adjacent monofilaments to each other in a flow
zone may be relatively strong compared to the interconnection of
the base strings to the flow zone which is substantially composed
of monofilament material. This feature allows, in some
applications, the removal of the base strings from the
monofilaments anytime after thermal fusing. Alternatively, the
adhesion between the monofilaments and the base string can be at
least as strong as the adhesion between monofilaments.
44. While FIG. 3 shows the monofilaments in a single row,
shoulder-to-shoulder, the density can be varied such that the
adjacent monofilaments do not touch each other. Also, the density
may be such that a second or greater number of rows of
monofilaments are stacked upon each other. Where eight (8) mil
nylon monofilament is used, for example, a density of about 125
monofilaments per inch of base string can be achieved with a single
row, shoulder-to-shoulder monofilaments.
45. While toothbrush embodiments have been described, any of the
wide variety of known brushes could be constructed using the arched
bristles, arch-and-loop bristle combinations or arch-and-straight
bristle combinations according to the present invention. For some
brush applications, the monofilaments may include abrasive
particles or grit material for particular brush applications.
Abrasive monofilaments are commercially available under the name
TYNEX.RTM. A by E. I. Du Pont De Nemours and Company of Wilmington,
Del. USA. Preferably, the abrasive material comprises 0-50% by
weight of the polymeric monofilaments. TYNEX.RTM. A is a 6,12 nylon
monofilament containing particles of silicon carbide or aluminum
oxide, which are distributed throughout the monofilament.
46. When ultrasonic welding is used, at least the monofilament or
the base string, preferably both, are made of thermoplastic
polymeric materials. These have been described above in reference
to other embodiments.
47. The monofilaments used in any of the above embodiments may be
co-extrusions of one or more polymers. Also, to achieve the desired
physical characteristics of the bristles used for applications such
as cleaning and scrubbing brushes, it has been found that the
preferred monofilaments are those having a diameter between 2 and
200 mils, and preferably between 2 and 20 mils. In a particularly
preferred embodiment for the toothbrush, the monofilaments are 4-10
mils in diameter. Monofilaments of different diameters,
cross-sections, materials, surface properties and/or colors can be
combined in one bristle assembly or sub-assembly to achieve
specific brushing characteristics and/or appearance.
48. In embodiments using nylon for either the monofilament or the
base string, or both, a preferred nylon is sold under the name
TYNEX.RTM., and is manufactured by E. I. Du Pont De Nemours and
Company of Wilmington, Del. USA. TYNEX.RTM. is polyhexamethylene
dodecanamide, which is the technical name for 6,12 nylon. It has a
melting point of between 208 and 215.degree.C. and has a specific
gravity of 1.05-1.07, and is available commercially in many shapes
and diameters.
49. Monofilaments and/or base strings suitable for use in the
present invention can have shapes other than circular
cross-sections, and may be hollow or have voids in their
cross-section. Embodiments described above show circular
cross-sectional shapes for the base string and monofilaments.
Either or both the base string and monofilaments could have oval,
rectangular, or other shapes. In any shape, the preferred
thicknesses for the base string and monofilaments are selected to
provide a level of functionality to the individual brush
applications.
50. With respect to the base string, the preferred embodiments
described above show a single strand of monofilament material.
However, the base string could be a bundle of monofilaments having
at least one of the monofilaments made of polymeric thermoplastic
material.
51. The polymeric monofilaments used for bristles in the various
embodiments described above can have other additives. For example,
the polymeric monofilaments could include 0-50% by weight particles
having functional and/or aesthetic quality. One example would be
particulate material that provides a color feature that would
enhance the visual appearance of the bristles. Other functional
particles could also be included such as anti-microbial additives
in the polymeric monofilaments. Other particulate materials or
coatings may be applied to or embodied within the monofilament such
as therapeutic agents or colorants, or other desirable additives.
Also, the monofilaments may be surface treated to provide desired
properties, such as to alter frictional coefficient.
52. The embodiments described above require "connection" between
the monofilaments and the base string. In this context,
"connection" means that the monofilaments are attached to the base
string by a frangible joint formed by melting, adhesive bonding,
solvent bonding, or similar means. The degree of frangibility can
be controlled so that, if desired, the base string can be easily
separated from the monofilaments after bonding.
53. The arched bristles described herein can be put on any brush
head in any configuration or pattern. For example, the arched
bristles may run parallel to or transverse the longitudinal axis of
the brush head, or transverse and longitudinal bristles can be used
concurrently. The head itself can have a substantially flat surface
from which the bristles extend upwardly, as shown in the
illustrated embodiments. Alternatively, the brush head can have a
shaped, i.e., curved surface, in which case the bristles would tend
to fan outwardly, for the case of a convex surface, or fan inwardly
for the case of a concave surface. Also, the two base strings of an
arched bristle sub-assembly can be mounted in the brush head in a
non-parallel fashion, such that the arched row of bristles adopt a
desired profile in which the apex of the arch changes along the
length of the row.
54. Although the invention has been described with reference to
several particular embodiments, it will be understood to those
skilled in the art that the invention is capable of a variety of
alternative embodiments within the spirit and scope of the appended
claims.
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