Improvements in and connected with Electrical Safety Cut-outs and Switches.
Year: 1889

page_text: Date of Application, 13th Dec., 1889
Complete Specification Left, 24th Mar., 1890-Accepted, 26th Apr., 1890
PROVISIONAL SPECIFICATION.
Improvements in and connected with Electrical Safety Cut-outs
and Switches..
CARRINGTON RIDDELL GORDON SMYTHE 140 Bath Street Glasgow, N.B.
Electrical and Mechanical Engineer, ERNEST PAYNE 140 Bath Street Glasgow, N.B.
Electrical and Mechanical Engineer, do hereby declare the nature of this invention
to be as follows:-
1. The combination in an electrical "cut out" or switch of an arrangement com-
posed of a piece of suitable material which can be charred, softened, melted, or
rendered brittle, by the action of heat and which is attached to or placed on or
round a suitable conductor carrying the current and also fastened or attached to a
switch, cut out, or other mechanical arrangement worked by a spring, weight, electro-.
magnet or other controlling force, in such a manner that when the aforesaid conductor
becomes heated the piece of suitable material or attachment gives way the switch or
cut out is then released and the circuit is broken.
2. In an electrical cut out where a fuse is employed the above arrangement may
be introduced to insure greater certainty of action. This is done by attaching the
arrangement to a weight or sharp edged piece of material worked by a spring,
weight, electromagnet or other controlling force, so, that when the suitable material
or attachment aforesaid gives way by the heating of the conductor the sharp edge
or weight strikes the fuse and severs or indents it. In the latter case the sectional
area of the fuse is diminished at the point of indentation allowing of greater heating
& consequent fusion.
Dated this Twelfth day of December 1889.
COMPLETE SPECIFICATION.
Improvements in and connected with Electrical Safety Cut-outs
and Switches.
CARRINGTON RIDDELL GORDON SMYTHE 140 Bath Street, Glasgow, N.B. Electrical
and Mechanical Engineer, ERNEST PAYNE 140 Bath Street, Glasgow N.B. Electrical
and Mechanical 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 :-
The object of our invention is to break the continuity of an electrical circuit and
to secure that the current in that circuit shall be stopped when it becomes excessive
or exceeds the amount which the conductor or conductors forming the circuit are
intended to carry, without the employment of a fuse or fuse wire.
We use the combination in an electrical cut-out or switch of an arrangement com-
posed of a piece of suitable material which can be charred, burnt, softened, melted or
rendered brittle by the action of heat. This piece of material is attached to or placed
on or round or in contact with a suitable conductor or conductors carrying the whole
or part of the current and is also fastened or attached to a switch, cut-out, or other
mechanical arrangement or device worked or actuated by a spring weight, electro-
magnet or other controlling force in such a manner that when the aforesaid conductor
or conductors become heated the attachment composed of the suitable material afore-
said gives way, the switch, cut-out or other mechanical arrangement or device afore-
said is then released and the circuit is broken.
For the aforesaid piece of suitable material or attachment we use a substance such

page_text: as hemp, flax, jute, cotton, silk, gut, skin, paper, hair, fibre etcetera, made preferably
in the form of a cord or tape, which can be readily attached or fastened to the
mechanical arrangement or device aforesaid and at the same time passed round or
placed in contact with the conductor or conductors carrying the current.
For the conductor aforesaid we employ a piece of wire or wires of such a section
and form as to permit the normal current of the circuit to pass through or along it
without heating.
We do not necessarily employ a separate wire or wires. The conductor or con-
ductors aforesaid may consist of the wire or wires forming the lead of the circuit
which it is desired to protect, the sectional area of the said lead being diminished at
the place where the attachment aforesaid is in contact with or passes round it, in
order to ensure heating at this place and not along the rest of the circuit. In the
case where the lead is composed of a stranded conductor or cable one or more of the
strands may be removed from or at the place where the attachment aforesaid is in
contact with or passes round the conductor or cable thereby diminishing the total
sectional area to the amount required.
Having now particularly described and ascertained the nature of our said Invention
and in what manner the same is to be performed, we declare that what we claim is :-
1. The combination, in an electrical safety cut-out, of a mechanical arrangement
or device for breaking the continuity of an electrical circuit with a conductor
carrying the whole or part of the current and an attachment substantially as
set forth.
2. The combination, in an electrical switch, of a mechanical arrangement or
device for working or actuating the said switch, with a conductor carrying the
whole or part of the current and an attachment substantially as set forth.
Dated this Twenty-second day of March 1890
CARRINGTON R. G. SMYTHE
ERNEST PAYNE.