Improved Manufacture of Brushes with Curved Backs.
Year: 1896

page_text: Date of Application, 10th June, 1896-Accepted, 11th July, 1896
COMPLETE SPECIFICATION.
Improved Manufacture of Brushes with Curved Backs.
I, CARL EDUARD FLEMMING of Schoènheide, Erzgebirge, Germany, Brush
Manufacturer, do hereby declare the nature of this invention and in what manner
the same is to be performed to be particularly described and ascertained in and
by the following statement :-
In manufacturing brushes with curved backs heretofore, the holes for the bristle
tufts have been prepared in such manner by boring or by punching that the brush
back and borer or punch were brought into the requisite different relative positions
for producing holes in the required positions.
For this purpose more or less complicated machinery was required, and
disadvantages also arise in such methods that will be presently referred to.
-
The present invention relates to the production of bristle holes in curved brush
backs of mouldable material, such as celluloid, while using the same simple
mechanism for forming the holes as that used for forming the holes in straight
brush backs. This is effected by forming the holes in the brush backs while these
are in a straight form, and then bringing the backs into the required curved form
either before or after the bristle tufts have been inserted.
In this method of operating, it is immaterial whether the holes are formed
entirely or only partially through the brush back. The alteration of the form of
the holes caused by the subsequent change of form of the brush back, is of
importance, as by this means the bristles of the tufts are either spread out or
brought closer together at their free ends, according as the back is bent into a
convex or concave form. According to this method brushes of any desired
curvature can be produced, such as brushes of a serpentine, spherical, ellipsoidal,
cylindrical, or other curved form. Also hollow brushes that is to say backs,
presenting hollows within which are bristle surfaces can be produced.
The method of manufacture will be more clearly understood on reference to the
accompanying drawing, in which Figure 1 shews by way of example the
manufacture of a double tooth brush which has at one end a convex brush surface,
and at the other end a concave brush surface.
The two brush backs a and b form with their stem c in the first place a straight
bar, in which the formation of the parallel bristle holes d is readily effected.
After these have been formed the brush body is introduced into a mould composed
of the two parts e, and f, and is thereby moulded into the shape indicated by the
dotted lines. The bristle holes are thus made to assume accurately the correct
position, if, for example the brush backs are curved in the form of circular arcs, as
indicated by the marked centres m, n, then the bristle holes will all receive radial
positions.
Fig. 2 shews as farther example of the manufacture of a serpentine or partly
convexly and partly concavely bent brush body and Fig. 24 shows a brush, the
back of which is more bent at the end than at the middle. Fig. 3 shews a
curved brush back for a brush whose handle is at right angles to the brush surface.
For all these constructions it is only necessary to employ devices for moulding or
shaping under pressure.
The pressing can be effected in all cases except those where hollow brushes are
to be produced, either before or after the introduction of the bristles the latter is
shewn at Fig. 4. In this case the one mould e lays hold of the brush back only at the
edges, close to the bristles, which are then situated in a hollow e' of the mould.

page_text: Fig. 5 shews a brush back which is bent in a direction at right angles to the
length after the introduction of the bristle tufts. The brush backs can also be bent
in both directions namely both lengthwise as at Figs. 1, 2, 3, and 4 and
transversely as at Fig. 5 and in the latter case either convex or concave.
If it be required to produce curved brushes in which the holes for the bristles shall
converge or diverge otherwise than in a manner due to the curvature of the back,
the bristle holes are formed in corresponding oblique positions in the back before
this is berit in the mould, as shewn at Figs. 6. and 7. In these examples the holes
diverge or converge already in the unbent brush back and by the bending, such
convergence or divergence is considerably increased. The bristle holes can thus
receive positions which it was impossible to impart to them in the ordinary method
of manufacture.
The holes could also be so formed that they would assume a position parallel to
each other after bending the brush back. Such brush backs can in addition receive a
convex or concave curvature in the transverse direction as at Fig. 5.
As before stated the bristle holes with brushes prepared according to this
invention differ from the bristle holes of ordinary brushes in that they experience a
change of form on the bending of the brush back as their openings become contracted
or expanded according as the brush back is bent concavely or convexly.
By this means in the one case the bristles of the separate tufts are kept closer
together and in the other case they are spread further apart. This action is
important for the production of a perfect brush surface as shewn at Figs. 8, to 11.
Fig. 8 shows part of a concave brush surface formed according to the present
invention and Fig. 9 shews the same formed in the old manner. It is assumed
that in both cases the bristle tufts are at the same distance apart. In Fig. 8 the
bristle tufts in consequence of the narrowing of the upper end of the holes, are
contracted the more together the more the brush back is curved.
In the old construction Fig. 9 the tufts penetrate one into the other and thus
afford a defective brush surface.
With convexly curved brush surfaces as at Fig. 10 the holes are expanded at
their mouths and in consequence hereof the ends of the tufts are spread out which
circumstance is very important in particular with long bristle tufts. With brushes
of ordinary construction as at Fig. 11 there are produced spaces between the
tufts if these are at the same distance apart as at Fig. 10.
Thus it will be seen that by the above described narrowing or widening of the
bristle holes on the curving of the brush back, there will always be produced a
continuous perfect brush surface if the distance between the holes be properly
chosen.
Fig. 12. shews as farther example a carriage brush in which the brush back a
provided with holes while flat, is afterwards bent either circular oval &c. either
before or after insertion of the bristles. The bending is in this case advantageously
effected upon a mandrily.
Fig. 13. shews a hemispherical brush, and Fig. 14 a brush of a domed form with
the corresponding moulds. In a similar manner ellipsoidal and other brushes with
any desired longitudinal and cross section can be produced.
Fig. 15. shows as example of a hollow brush a cylindrical brush the interior of
which is provided with a brush surface.
This brush is produced simply by bending round by means of suitable tools a
flat brush back the length of which corresponds to the periphery of the cylinder
Fig. 15. and which has previously been provided with bristle tufis in such manner
that the latter are situated inside. In the same manner the ellipsoidal brush
indicated in dotted lines at Fig. 12 or the hemispherical brush shewn at Fig. 13
can be formed as a hollow brush.
It will be evident that according to the above described method a great variety
of differently formed brushes of hitherto unknown configurations can be manu-
factured merely by employing suitable tools for moulding brush backs into the

page_text: required shapes after these have had the bristle holes formed in them while in the
flat condition.
This method also enables larger brushes such as silk hat brushes, carriage
brushes &c. to be manufactured in a simple and inexpensive manner and of the
exact form required.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
The method of manufacturing brushes with curved backs which consists in
forming the holes for the bristle tufts in the brush back while this is still flat and
then bringing this by bending pressing rolling or other means into the desired
curved form either before or after the insertion of the bristle tufts whereby the
bristle holes have their direction and the size of their openings altered so that the
bristle tufts are brought into any desired position and are brought closer
together or spread further apart at their ends substantially as described.
Dated this 10th day of June 1896.
ABEL & IMRAY,
Agents for the Applicant.