Improvements in Chill Moulds for Casting the Teeth on Gear Wheels.
Year: 1893

page_text: Date of Application, 4th July, 1893-Accepted, 12th Aug., 1893
COMPLETE SPECIFICATION.
Improvements in Chill Moulds for Casting the Teeth on
Gear Wheels.
I, SAMUEL EDWARD MAXWELL, Manufacturer, residing at Fifth Street,
Aspinwall, in the County of Allegheny and State of Pennsylvania, United States
of America, do hereby declare the nature of my invention, and in what manner the
same is to be performed, to be particularly described in and by the following
statement:-
The object of the invention is to manufacture gear wheels, which shall be much
more durable and accurate than those made by the processes now in use. There are
two processes by which gear wheels are now usually made. By the first process,
the wheel is cast solid and the teeth are cut in it afterward. By this method, it is
necessary to cut into the soft part of the iron, thus forming a soft surface on the
tooth of the wheel which quickly wears out. By the second process, the wheel,
teeth and all, is cast in green sand. The wheels cast in this way are somewhat
more durable; but in order that the wheel, when cast, may be lifted out of the
mould, the teeth must be tapered in a manner that somewhat spoils their shape.
By my invention it is intended to cast the wheel in the usual manner of casting
them in green sand, except the teeth, which are formed in my cast iron chill mould.
By this method, as the hot metal which forms the teeth is poured into the mould,
it comes in contact with the cold iron of the mould, and by this means the surface
of the teeth is chilled and hardened, forming a true wheel with teeth having a
hard durable surface.
The chill mould consists of a cast-iron ring divided into segments, varying in
number according to the number of teeth in the wheel to be cast.
In the drawing hereto attached,
Figure 1 represents a top view of the mould.
Figure 2 is a section of a mould and casting taken through the line A-B.
"E" is a casting of a gear wheel.
"D" is a sectional ring composed of a number of segments, to be determined
by the number of teeth in the wheel to be cast.
"C" is a cast iron ring. This ring has a taper on the inner edge, as hereinafter
stated; and it draws together, clamps and holds the segments of the ring "D"
in position.
The outer edge of the sectional ring "D" and the inner edge of the ring "C"
are tapered, so that when placed together the segments may be drawn tightly into
position around the pattern.
In the under side of the section ring “D” there is a groove which is shown in
Figure 2 of the drawing by the letter H.
D" is the sectional ring; "C" is the outer cast-iron ring; "E" is the casting
of the wheel. In this figure "G" shows the taper in rings "D" and "C" above
referred to.
As an additional precaution and device for holding the segments of the ring "D"
in place, a third cast-iron ring is used, which is shown by dotted lines in Figure 1
of the drawing, and by letter "F" in Figure 2. The segments of ring D are
placed upon this cast-iron ring, and there is a tongue on ring F, which fits into the
groove H in the segments of ring D, holding them firmly in position.
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 combination of the sectional ring D, having the taper on the outer edge and

page_text: the groove H on the under side thereof; the outer cast-iron ring C with the taper
on the inner edge corresponding to the taper on ring D, and the under cast-iron
ring F, with the tongue fitting into the groove H in segments of ring D.
Dated this 4th day of July 1893.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.