Improvements in Bases, Covers, and Fixings for Electrical Safety Fuses, Switches, and the like.
Year: 1890

page_text: Date of Application, 21st Feb., 1890-Accepted, 22nd Mar., 1850
COMPLETE SOLEIVATION.
Improvements in Bases, Covers, and Fixings for Electrical Safety
Fuses, Switches, and the like.
1, WILLIAM WHITE, of the Firm of Poole and White, of N.). 58 Bread Street, in
the County of London, Electrical Engineer, 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 :-
For the bases and covers of electrical safety fuses, switches and the like, it is desirable
to employ ceramic material which is cheap, incombustible, and a good insulator, but
does not conveniently lend itself to the necessary metallic attachments. My inven-
tion relates to means of making such attachments and fixings to ceramic material as I
shall describe referring to the accompanying drawings.
Fig. 1 is a longitudinal section, Fig. 2 a transverse section and Fig. 3 a plan with
cover removed of a safety fuse introduced between two lengths of conducting cable.
The ceramic base A is made with lugs B by which it can be screwed to a wall or
other part. It has in the middle a raised part at each end of which there is a slot a
and an undercut part a'. Into each of these slots is inserted a T shaped metal
piece B which presents at its end a socket for receiving the end of the cable
soldered into it and which has a stem b' turned upwards and threaded to receive
nuts screwed upon it. When the pieces B are inserted in the slots a, the limbs of
the T lying in the under cut part a', nuts C with washers under them are screwed
on the upright stems firmly securing the pieces B to the base.
The wire or metal strip F serving as safety fuse is then secured between the
nuts Cand washers and thumb nuts D.
The whole is covered by the lid or cap E which is held on by a spring G. This
spring is attached to the base A by screwing it to a dovetail metal piece H inserted
in a dovetail slot in the underside of the base, the points of the screws which fix the
spring to the piece H entering holes in the base A and so preventing the piece H
from shifting.
By applying the finger to the top of the spring G, the lid E can be released and
removed. Fig. 4 is a vertical section of a ceramic base and screwed-on cap of circular
form suitable for a fuse or switch; Fig. 5 is a side view and Fig. 6 is a plan of the
base, with the cap removed.
Each of the metal plates K which receive the screws for the connecting wires is
held to the base by a screw k passed through it into a nut L inserted from the end
into a round hole formed in the ceramic material.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that whai I
claim is :-
1. The herein described method of fixing a metal piece to the ceramic base of an
electrical instrument by inserting it or a nut secured to it by a screw into a slotted
and undercut hole formed in the ceramic material.
2. An electrical safety fuse having ceramic base and cap hold by a spring sub-
stantially as herein described with reference to Figs. 1, 2 and 3.
Dated this 20th day of February 1890.
ABEL & IMRAY,
Agents for the Applicant.