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To all whom it may concern: Be
it known that I, SAMUEL OAKMAN,
of Boston, in the county of Suffolk and State of Massachusetts, have
invented a certain new and useful Mold for Telegraphic Insulators, of
which the following is a specification: The
Nature of the Invention. The
nature of my invention consists in constructing a device for forming a
screw-thread on the inside of glass insulators. Said device, called a
"point," is made of an outside tube, the tube being slotted, and
provided with screw-thread bearing segments which fit into slots, and may
be withdrawn radially and thus free themselves from the molded glass. The
segments being dovetailed to a coned spindle which fills the interior of
the tube. Description
of the Drawing. Figure
1 is an elevation of the invention. Fig. 2 shows the same in vertical
section. Fig. 3 is a cross-section through the lower part of the same. General
Description. Let A represent the outer tube or |
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point, which forms the interior of the insulator. This
tube has slots B, Figs. 1 and 3, in which the segment thread-bearing
pieces C C C rest. These
pieces C C C are dovetailed to the center piece D, which is made conical
and so as to slide up and down in the tube A. As the pieces C C C have
no longitudinal motion it is evident that an upward motion of the center
piece D will cause the pieces C C C to be drawn inwardly, as indicated
by the dotted lines. To
form the screw in the insulator the "point" is inserted with
the spindle D clear down, as shown in full lines in Fig. 2. When the
glass has set the spindle D is drawn up, which causes the pieces C C C
to draw inwardly and thus free themselves from the inwardly - projecting
thread on the inside of the insulator. I
claim as my invention-- The
combination of the tube A, the spindle D, and the segment-pieces C C C,
operating substantially as described, and for the purpose set forth.
SAMUEL OAKMAN. Witnesses: A.
HUN BERRY, FRANK G. PARKER. |