IMPROVEMENTS IN COMBS, FORMED FROM À SERIES OF INDEPENDENT TEETH AND PROCESS FOR UNITING THE SAME BY A BACK OF PLASTIC MATERIALS
Year: 1884

page_text: I, WILLIAM CRABB, of 107 Bloomfield Avenue, Newark, New Jersey, United
States of America, Manufacturer, do hereby declare the nature of my invention
for "IMPROVEMENTS IN COMBS, FORMED FROM À SERIES OF INDEPENDENT
TEETH AND PROCESS FOR UNITING THE SAME BY A BACK OF PLASTIC MATERIALS,"
and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement:-
The plastic materials used by me are pyroxylene, vulcanite or hard rubber and
other non-metallic compositions adapted to weld and mold under pressure below
125 degrees Centigrade. The process I employ consists 1st, in supporting the
required set of teeth and a strip or strips of the plastic material between the parts
of a divided mold; 2nd in subjecting the mold and its contents to the required
degree of heat and pressure; and 3rd in cooling the material thus pressed about the
roots of the teeth to hold them together.
My improvements also include a strengthening wire in the back of the comb, and
a special method of forming flat or oval teeth, and the nature of my invention will
be understood by reference to the annexed drawing, in which Fig. 1 is a side view
of a small pocket-comb. Fig. 2 represents the die or mold in section, separated
sufficiently, to introduce the comb teeth and strips of plastic material.
Fig. 3 represents a section of the mold, the tooth holder, the teeth, and the comb-
back at the close of the pressing operation. Fig. 4 is a view of the holder and the
closed mold, a portion of the latter being broken away to show the comb inside, and
a portion of the comb-back being also cut away to show the arrangement of the
teeth and strengthening wire in the interior of the back.
Fig. 5 is an inside view of one half of the mold; Fig. 6 is a side view of one of
the tapered blanks for the flat teeth a³, and Fig. 7 is a section of the same near the
root of the teeth after flattening.
Fig. 8 represents the arrangement of the teeth and strengthening wire with a
U shaped strip of the plastic material before pressing. A is the back of the comb;
B, B the halves of the mold properly shaped to fit around the roots of the teeth, by
notches shown at 6 in Fig. 5; and the space shaped to form the back of the comb
being surrounded by a narrow ledge and an adjacent channel to remove the surplus
material, as in similar operations; the ledge being shown at d in Fig. 5, and the
channel at e in Figs. 3 and 5.

page_text: C is the holder; a bar provided with holes of the proper size and depth to
sustain the teeth, with their roots projecting a suitable distance to penetrate the
mold nearly to the rear of the back. f, f are strips of the raw material prepared
for insertion in the mold to form the back under pressure. a, a, a², a³, are different
forms of the teeth shown herein, and g is á blank pin tapered to receive a flattening
pressure, to form the so-called large teeth of the comb.
For the purposes of this invention, the teeth may be made of other substances
than metal as ivory, bristles, wood &c., the process being adapted to unite such
teeth securely to the back without injury to the teeth; but to prevent the roots of
metallic teeth from coming out of the comb-back when in use, I find it desirable
to crimp, split or roughen the roots in some manner, and have shown the same in
the sectional view in Fig. 4. At a is shown a group of teeth expanded by pressure
at the root into dovetail shape; at a' are shown similar teeth forked by splitting
such a flattened tooth; and at a² are shown teeth with crimped ends.
. Other forms may also be devised to retain the teeth in the back as by notching
and roughening.
At a³ are shown the so-called "large teeth" for the comb; which I form by first
tapering a bit of wire of suitable size and length, and then flattening the same by
pressure. The large teeth are thus of the desired flat and tapering form, while the
edges are nicely shaped by the initial preparation.
The strengthening wire c is embedded in the plastic material near the roots of
the teeth, by inserting it in the mold between two surfaces of the blank substance
used to form the back. Such substances may be formed of two flat strips, as shown
in Fig. 2, or of one strip bent into U form as shown in Fig. 8; in which latter
figure the wire c is represented as cemented lengthwise in the bottom of the U to
hold its place in the mold. In either case the material lies upon each side of the
roots of the teeth when molding, and is thus forced into contact around and
between the same under the influence of the heat and pressure applied.
Teeth of any shape, and back of any form may be made and united by this
process; the teeth when prepared, being inserted in the holes in holder C and thus
held between the strips of blank material, between the sides of the mold as shown
in Fig. 2; the mold being preferably laid upon one side on the bed of a suitable
press, and the holder being supported by contact with the edge of the mold, as
indicated in Fig. 4.
With the use of pyroxylene compounds, the back and comb may be removed
from the mold as soon as they can be heated (which is generally on a steam table
before pressing), pressed and cooled; but with vulcanite the inolds are clamped
together after pressing and subjected for a proper time to the temperature required
for vulcanizing the india-rubber.
I am fully aware that combs have been made by soldering and cementing
separate teeth into metallic backs, and by compressing a metallic U shaped back
upon separate teeth. I therefore disclaim such operations; my invention relating
entirely to backs formed of plastic material which cannot be molded cold or poured
into a mold in a fluid state, but are adapted to mold readily at a temperature
below 125 degrees centigrade.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is.
1st
: The process herein shown and described for the manufacture of hair combs,
consisting in molding a back of plastic material between and around the roots
'of the teeth, as and for the purpose set forth:

page_text: 4th
The combination, with a series of separate teeth molded in a back of plastic
material; of a strengthening wire c extending lengthwise inside the back.