Improvements in Insulators for Electrical and other Purposes.
Year: 1892

page_text: Date of Application, 25th Oct., 1892-Accepted, 3rd Dec., 1892
COMPLETE SPECIFICATION.
[Communicated from abroad by JOHNS-PRATT COMPANY, of Capitol Street,
City of Hartford, County of Hartford, State of Connecticut, United States of.
America.]
Improvements in Insulators for Electrical and other Purposes.
1, HENRY HARRIS LAKE, of the firm of Haseltine, Lake, & Co., Patent Agents,
45 Southampton Buildings, in the County of Middlesex, 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 :-
My invention has for its object to provide a durable and efficient heat or
electrical insulator and it consists in an insulator the insulative portions of which
are made from mica, which is employed in the particular manner hereinafter set
forth. I am aware that the insulative qualities of mica have long been known but
its full efficiency and value in the manufacture of insulators has not hitherto been
fully understood, so far as known to me.
My invention will be readily understood from the following description of several
forms of insulators which are made in accordance therewith. I have shown several
such forms embodying my invention in the accompanying drawings and in the
following description I will refer specifically thereto.
In the said drawings
Fig. 1 is a view of a handle which may be employed for electrical switches and for
articles which require to be handled while hot. In said Fig. 1 the mica is shown
in section.
Fig. 2 is a view of a similar handle modified by the addition of a metallic cap;
the mica and said cap being shown in section in said Fig. 2.
C
Fig. 3 is an elevation partially in section of what is termed a pole" insulator,
it being commonly used on poles for the support of electric wires.
"
Fig. 4 is a "hanger or insulating support, shown in vertical section, such as
may be employed in supporting the overhead conductors or trolley wires of
electric railways.
23
Fig. 5 is a view partially in section of another form of "hanger or insulating
support for overhead wires.
In
In the use hitherto of mica as an insulator the thickness of the sheets has been
interposed between the objects or parts to be insulated, that is to say, the sheets of
mica have been wrapped, for example, around the piece of metal to be insulated
so that the insulation is effected in the direction of the thickness of the mica.
the manufacture of my improved insulator, I lay the sheets of mica, one upon the
other, compress them firmly together and embed therein the part or parts to be
insulated in such manner that the insulating material is radially disposed relatively
to said part or parts.
and a nut
In the manufacture of a handle such as is shown in Fig. 1 I employ a core or
rod of metal a, which is provided with a suitable head b, a number of sheets of
mica are then provided each having a central aperture therein and these are
strung or placed on the rod a. A washer is then preferably placed on the rod
is screwed against the washer, the core being threaded for that purpose.
By this means,
if the sheets of mica are not previously compressed together, they
may be firmly compacted and compressed while on the rod a. The handle thus
formed may then be placed in a lathe and the sheets of mica turned down to the
desired form. From the peculiar character of the mica, it may be turned and
polished when firmly compacted together as described and will after being thus
treated be similar in appearance to horn. When the sheets are most closely
'

page_text: compacted the union is so intimate that a transmitted beam of light shows a play
of iridescent colors through the mass. Such an insulator will withstand extreme
changes of temperature without deterioration or impairment; possesses very high
insulating quality and is comparatively inexpensive. It will be noted that the
insulation effected by such an insulator or handle is in the direction of the radii of
the sheets or disks of the mica.
In Fig. 2 of the drawings the handle above described is shown in a modified
form, the mica being turned down at one portion to form a parallel sided seat upon
which the knob or cap is secured. I prefer to secure the cap h by shrinking it to
its seat on the mica. This is effected by heating the cap h, and then thrusting into
the open end of the cap the portion of the mica insulator which has been formed
to fit the opening in the cap this portion of the mica insulator should fit the
opening in the cap very snugly so that when the cap portion shrinks to its seat it
will be firmly attached to the mica.
proper
In the form of pole insulator shown Fig. 3 a number of sheets of mica of
thickness are laid and compressed together, apertures being formed therethrough
at intervals to receive the retaining bolts a'. These are then placed in position
and firmly headed down, forming a solid and durable block of mica. An aperture
or socket may then be formed in this block to receive the spindle which projects
upwardly from the support which is secured to the pole or upright. The
exterior of the block of mica d may be turned down or cut to any desired shape,
and may be provided with an annular groove to receive the wire m. In forming
the insulating block for this insulator, I deem it preferable to punch or cut the
holes for the bolts as also the central hole for the spindle, in each sheet of the
material before the sheets are laid together; the bolts are then inserted and secured
and the exterior surface of the block turned or finished...
In adapting my invention to a hanger or overhead insulator for electrical
conductors, a suitable bell or casing n which is preferably provided with a skirt
to shed moisture is formed by casting or in any well-known manner, the said beli
being provided with lugs by means of which it may be secured to a span wire or
transverse support. A rod or stem af which has a suitable head is provided with a
series of sheets of mica strung thereon in the manner heretofore described, and
which are turned down or ent to the proper shape.
り
Another series of sheets of mica or a mass of comminuted mica may be placed in
the top of the cavity of the bell, or it may be left unfilled as is the top of the
insulator shown Fig. 2. The said stem, and the sheets strung upon it are then
placed inside the bell and the retaining ledge or projection is then turned over
against the mica within the bell thus securing the whole in place. The clip d to
which is firmly attached by solder or otherwise, the conductor f', is then screwed
onto the lower end of the stein a² and the hanger is secured in position. It will be
noted that a considerable portion of the stem a projects below the body of the
bella and that said portion is covered by a series of sheets of mica which are strung
thereon and which are of less diameter than the sheets within the bell but which
serve effectively to insulate the stem from the lower portions of the bell.
The hanger shown Fig. 5 is very similar in construction to that shown Fig. 4, but
instead of the lugs 7 the body of the bell is provided exteriorily with two annular
projections between which is placed a collar from either side of which
project securing arms to which the span wire or transverse support is made fast.
The body of the bell and its contents may thus be turned or revolved after the bell
has been secured to the transverse support. In order to facilitate turning the bell
when in position I have provided at the top thereof a projection m¹ to receive a
wrench. This construction renders the attachment of the clip to the stem a
much more easy as after the clip is soldered to the conductor and the insulator
is in place the clip is brought into position in contact with the end of the stem a²
a wrench applied to the projection m² and the body of the insulator turned until the
stem is firmly screwed into the recess or socket made to receive it in the
clip d.

page_text: My invention may be applied to a large variety of insulators, those shown and
above described will however serve to illustrate fully the scope of its application.
In each case the insulation is exceedingly durable, and as will be noted is
obtained by a series of sheets of mica which are compressed together and which are
interposed in the direction of their radii between the objects which are to be
insulated.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondents I declare that what I claim is :-
1. An insulator composed of parallel layers of mica strung on a suitable support,
substantially as set forth.
2. An insulator comprising an insulation block composed of a series of sheets of
mica compressed and compacted together, the said block having a parallel sided
seat formed thereon and a metallic cap or casing enclosing or partially enclosing
the said block, tightly compressing the seat thereon and held on the seat by
frictional contact, substantially as set forth.
3. An insulator comprising a core and a series of sheets of mica strung on said core
and closely compressed and compacted together thereon, said mica having a parallel
sided seat formed thereon and a metallic cap or casing enclosing or partially
enclosing the mica on said core and tightly compressing the seat thereon and held
on the seat by frictional contact, substantially as set forth.
4. An insulator comprising an insulating block composed of a series of sheets of
inica and means whereby said sheets are suitably secured together, combined with
a spindle or support therefor passing partially through said block, substantially as
set forth.
5. An insulator comprising an insulating block, securing bolts as a', and a
spindle as j, substantially as set forth.
6. An insulator comprising an outer case, a rod or stem placed within the said
case and insulated therefrom by a series of sheets of mica, said sheets of mica being
radially disposed with relation to said stem, substantially as set forth.
7. An insulator comprising an outer case or bell a rod or stem placed within the
said bell, and insulated therefrom by a series of sheets of mica and having that
portion of the stem which projects beyond the mica in the case partially covered by
a series of sheets of mica placed thereon, substantially as set forth.
8. An insulator comprising an outer case, a rod or stem placed within the said
case and insulated therefrom by a series of sheets of mica, said case being provided
with a retaining ledge or projection for the purpose of holding the insulation
within the bell, substantially as set forth.
9. An insulator comprising a bell or case, an insulating block within said case, a
connecting stem or rod insulated from said case by said block, a collar surrounding
said case and loosely secured thereto and means for securing said collar to the
insulator support, whereby the case, and insulation and insulated parts contained
therein may be rotated within the collar for the purposes and substantially as set.
forth.
10. An insulator consisting of a bell or case, having the projections g ' thereon,
a collar and means as the arms for securing the collar to its support,
substantially as set forth.
11. An insulator consisting of a case or bell, having projections h¹ g¹ and provided
with a projection m' to receive a wrench and having a collar provided with
suitable arms for securing it to its support, substantially as set forth.
Dated this 25th dore of October 1802
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.