UNITED STATES PATENT OFFICE
FRED M. LOCKE, OF VICTOR, NEW YORK.
No. 1,091,678 Specification of Letters Patent. Patented Mar. 31, 1914.
Application filed May 19, 1909 Serial No. 497,095.
To all whom it may concern:
it known that I, FRED M. LOCKE,
a citizen of the United States, and resident of Victor; in the county of
Ontario and State of New York, have invented certain new and useful
Improvements in Insulating Compositions, of which the following is a
invention relates to a plastic composition adapted for various purposes,
but particularly for use as electric insulating material.
object of the invention is to produce a composition which shall have
both a greater electrical resistance than ordinary glass or earthen
compositions, and at the same time great toughness and resistance to
changes in temperature.
porcelain, and glazing materials as ordinarily compounded contain
certain comparatively refractory materials which may be designated as
bases, and certain comparatively fusible elements commonly termed
fluxes. Among the latter
boron compounds and various metal salts, such as zinc oxid, iron oxid,
sodium carbonate &c., are commonly used.
I have discovered, however, that most of such materials used as
fluxes are deleterious to a composition with respect both to insulating
properties and to mechanical toughness and resistance to changes in
temperature. I have further
discovered that, in connection with a base consisting chiefly of a
fusible aluminum silicate such as potash-feldspar or common clay, a flux
may be used consisting entirely, or substantially entirely, of a fusible
boron compound such, for example, as borax, colemanite, or boracic acid,
and that the composition so produced is much superior to those produced
by the use of fluxes of other character both with respect to insulating
qualities and with respect to its mechanical qualities.
This composition may vary widely in the proportions in which its elements are used, and it may be made either opaque or transparent, according to the degree of heat to which it is subjected in
firing. It has been found possible to direct a
blow-pipe flame upon a thick body of such material until a hole is
melted through the same without the production of cracks. Furthermore,
plates or blocks of the material may be dipped alternately into ice
water and into boiling water, without cracking or injuring them.
The electrical resistance has also been demonstrated to
be higher than that of either glass or porcelain.
In practice I have found that suitable proportions for
the elements of my composition are as follows: feldspar 100 parts,
boracic acid from 5 to 100 parts, in accordance with the toughness and
electrical resistance required.
I am aware that it has been previously proposed to make
an insulating composition including both feldspar and borax as elements,
but in such composition these elements have been used merely as a flux
for asbestos, clay and other substances, the principal characteristic of
the composition resulting from the latter substances. So far as I know,
it is new to produce a homogeneous body consisting wholly, or
substantially wholly, of fusible aluminum silicate and fusible boron
compound, and I am the first, so far as I am aware, to discover the
useful combination of mechanical and electrical characteristics which
this substance possesses, and which give it value as insulating
1. An insulating compound consisting of an aluminum
silicate and a boron compound fused together in a homogeneous body.
2. An insulating compound consisting of an aluminum
silicate having a boron compound incorporated therein.
FRED M. LOCKE.