Improvements in or connected with Automatic Electrical Cutouts.
Year: 1899

page_text: Date of Application, 11th Dec., 1899
Complete Specification Left, 10th Sept., 1900-Accepted, 20th Oct., 1900
PROVISIONAL SPECIFICATION.
Improvements in or connected with Automatic Electrical Cutouts.
We, FRANK EDWARD GREENSTREET, of 33, Brooke Street, Holborn, in the
County of Middlesex, Engineer, and EDWIN JOHN SELBY, of Prospect Villa,
Hillaries Road, Gravelly Hill, Birmingham, in the County of Warwick, Elec-
trical Engineer, do hereby declare the nature of this invention to be as follows:-
-
The invention relates to improvements in or connected with automatic elec-
trical cut outs of that class in which a fusible wire is employed to effect the
required break in the continuity of the current upon the heating of the con-
ductor due to the current meeting with a dangerous resistance or a current
in excess of the normal current passing in the circuit and the object of the
present invention is to obtain a simple and inexpensive device by the aid of
which the break will be accomplished in a more effectual manner than heretofore.
In carrying the invention into effect a box of cast iron or other suitable
material provided with removeable covers is employed and this box is divided
into two compartments by means of a central partition of cast iron or preferably
insulating material and upon each side of the partition is fixed a slab or base
of any suitable insulating material such for example as slate, porcelain or fibre.
Upon one of the insulating slabs is fixed a metallic stud which is effectually
insulated from the partition and fixed with this stud is a contact plate provided
with a terminal and binding screw to clamp in position the end of the lead or
conductor which passes into the box through an aperture provided for that
purpose.
The stud has pivotally mounted thereon a metallic holder in which is fixed
a hollow rod or arm of carbon or other suitable material and said holder is held
in position upon the stud by a circular nut and acted upon by means of a
spring coiled around the stud or otherwise arranged which exerts a constant
tendency to turn the holder into a position parallel with the side or end of
the box.
Fixed with the stud is a short arm or offset which carries a second terminal
and binding screw and in this terminal is clamped one end of a length of
fusible wire which passes partly around the circular nut and through the
hollow carbon arm.
Upon the same insulating slab and upon the same side thereof but at a
corner diagonally opposite that in which the aforesaid stud is fixed is pro-
vided a second stud and duplicate set of parts to which the other end of the
lead or conductor which passes through that end of the box is connected.
In order to set the cutout the carbon arms are turned into a diagonal position
against the force of the springs with their ends nearly in the same line and
the length of fusible wire from the first carbon arm is passed through the
second arm to the terminal of the stud to which its other end is clamped and
the carbon arms. are thus held in their diagonal position by the short loop or
length of fusible wire extending between their ends and over which short
length of fusible wire the total current is necessarily carried.

page_text: A similar set of parts is arranged upon the other slab or base and to which
the other lead which completes the circuit is similarly connected.
So long as the current passing along the leads or conductors is a normal one
the short length or loop of fusible wire between the ends of the carbons will
remain intact but upon the current meeting with a troublesome resistance or
the volume of the current being suddenly increased or if from other cause
undue heat is generated in the circuit the fusible wire between the ends of
the carbon arms will become fused and the carbon arms will by the action of
the springs simultaneously swing apart into their parallel positions notwith-
standing that the fusible loop may be coated with a film of oxide the strength
of the springs being sufficient to break said film.: [..
The current will thus be effectually broken without liability to flash and
the remaining lengths of fusible wire by reason of being clamped to the offset
terminals and passed around the circular nuts will in the movement of the arms be
shortened up and their fused ends drawn into the hollows of the carbon arms
so that no danger can arise therefrom inasmuch as the arc is shifted from the.
metal to the carbons which take up and by reason of their separation break or
destroy the same.
By the peculiar arrangement of the two sets of carbon arms upon insulating
slabs located at opposite sides of the partition the possibility of a workman or
attendant inadvertently completing the circuit whilst adjusting the fusible wire
is avoided.
It will be obvious that the details of construction of the device may be
otherwise modified without departing from the spirit of the invention.
By the means herein before described a simple and inexpensive automatic cut-
out is obtained which is instantaneous and otherwise highly efficient in its
action whilst possessing other advantages.
WHITE & WOODINGTON,
Birkbeck Bank Chambers, London,
Agents.
Improvements in or connected with Automatic Electrical Cutouts.
We, FRANK EDWARD GREENSTREET, of 33, Brook Street, Holborn, in the
County of Middlesex, Engineer and EDWIN JOHN SELBY, formerly of Prospect
Villa, Hillaries Road, Gravelly Hill, Birmingham, in the County of Warwick,
but at present residing at 75, Nelgarde Road, Catford Bridge, in the County
of Kent, 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:-
The invention relates to improvements in or connected with automatic elec-
trical cut outs of that class in which a fusible wire is employed to effect the
required break in the continuity of the current upon the heating of the con-
ductor due to the current meeting with a dangerous resistance or a current
in excess of the normal current passing in the circuit and the object of the
present invention is to obtain a simple and inpensive device by the aid of
which the break will be accomplished in a more effectual manner than heretofore.
In carrying the invention into effect a box of cast iron or other suitable

page_text: material provided with removeable covers is employed and this box is devided
into two compartments by means of a central partition of cast iron or preferably
insulating material and upon each side of the partition is fixed a slab or base,
of any suitable insulating material such for example as slate porcelain or fibre.
Upon one of the insulating slabs is fixed a metalic stud which is effectually
insulated from the partition and fixed with this stud is a contact plate provided
with a terminal and binding screw to clamp in position the end of the lead or
conductor which passes into the box through an aberture provided for that.
purpose.
The stud has pivotally mounted thereon a metalic holder in which is fixed
a hollow rod or arm of carbon or other suitable material and said holder is held
in position upon the stud by a circular nut and acted upon by means of a
spring coiled around the stud or otherwise arranged which exerts a constant
tendency to turn the holder into a position parallel with the side or end of
the box.
Fixed with the stud is a short arm or offset which carries a second terminal
and binding screw and in this terminal is clamped one end of a length of
fusible wire which passes partly around the circular nut and through the
hollow carbon arm.
Upon the same insulating slab and upon the same side thereof but at a
corner diagonally opposite that in which the aforesaid stud is fixed is pro-
vided a second stud and duplicate set of parts to which the other end of the
lead or conductor which passes through that end of the box is connected.
In order to set the cutout the carbon arms are turned into a. diagonal position
against the force of the springs with their ends nearly, in the same, line and
the length of fusible wire from the first carbon arm is passed through the
second arm to the terminal of the stud to which its other end is clamped and
the carbon arms are thus held in their diagonal position by the short loop or
length of fusible wire extending between their ends and over which short.
length of fusible wire the total current is necessarily carried.
A similar, set of parts is arranged upon the other slab or base and to which
the other lead which completes the circuit is similarly connected...
.:
..So long as the current passing along the leads or conductors is a normal one.
the short length or loop of fusible wire between the ends of the carbons will
remain intact but upon the current meeting with a troublesome resistance or
the volume of the current being suddenly increased or if from other cause.
undue heat is generated in the circuit the fusible wire between the ends of
the carbon arms will become fused and the carbon arms will by the action of
the springs simultaneously swing apart into their parallel positions notwith-
standing that the fusible loop may be coated with a film of oxide the strength:
of the springs being sufficient to break said film.
The current will thus be effectually broken without liability to flash and
the remaining lengths of fusible wire by reason of being clamped to the offset
terminals and passed around the circular nuts in the movement of the arms be:
shortened up and their fused ends drawn into the hollows of the carbon arms
so that no danger can arise therefrom inasmuch as the arc is shifted from the
metal to the carbons which take up and by reason of their separation break or
destroy the same..
By the peculiar arrangement of the two sets of carbon arms upon insulating
slabs located at opposite sides of the partition the possibility of a workman or
attendant inadvertently completing the circuit whilst adjusting the fusible wire
is avoided.
It will be obvious that the details of construction of the device may be
modified without departing from the spirit of the invention.
And in order that the said invention may be more clearly understood and readily
carried into effect we will proceed aided by the accompanying drawings more'
fully to describe the same.

page_text: DESCRIPTION OF THE DRAWINGS.
Figure 1 is a vertical longitudinal section taken on the line 1-1 of Figure 2
of an automatic electric cut out constructed according to the present invention.
Figure 2 is a vertical transverse section taken on the line 2-2 of Figure 1 and
Figure 3 is a side view of parts showing one of the carbon arms in the
vertical or parallel position which they assume after the break has been effected.
In the several figures in which like parts are indicated by similar letters of
reference Figure 3 is drawn to an increased scale with respect to the other
figures of the drawings.
a represents a box of cast iron or other suitable material which is provided
with covers or lids a¹ hinged at a to the upper part of the box a and secured
in position by means of screws a passing through plain holes in ears at formed
on the covers a¹ and screwing into threaded holes provided in bosses or lugs a
formed on the box a.
The box a is divided into two compartments A and B by means of a central
partition a of cast iron or it might be insulating material and upon each side
of the partition as is fixed a slab or base b of any suitable insulating material
such for example as slate, porcelain or fibre.
Upon one of the insulating slabs and within the compartment A is mounted
a metallic stud c which has cast therewith a contact plate hereinafter, more
fully referred to which bears against the face of the slab b and beyond said
contact plate the stud c is received into a hole provided in the slab b and securely
fixed in position by means of a nut 2 screwing onto the threaded end of the
stud c said stud and nut being effectually insulated from the partition a and
adjacent parts by means of a disc b₁ of insulating material covering the end
of the nut and stud and by an opening a provided in the partition aº.
The contact plate c¹ is provided with a terminal and binding screw c to
clamp in position the end of the - lead or conductor d which passes into the box a
through a perforated insulating plug 62 fitted into an apertured boss as formed
on the side of the box a.
1
The stud c has pivotally mounted thereon a metallic holder e which is held
in position by means of a circular nut ca screwing upon the outer threaded end
of the stud c and in the holder e is fixed a hollow rod or arm e¹ of carbon or other
suitable material but preferably of carbon and said holder is acted upon by
means of a spring e² coiled around the stud c and at one end fixed therewith and
at the other end fixed with a stud e projecting from the holder e or it might
be otherwise arranged which exerts a constant tendency to turn the holder e
and consequently the arm el into a vertical position parallel with the side or end
of the box a as indicated by the thick dot and dash lines in Figure 1 or to such
a position as will prevent the current forming a circuit through the metallic
box.
Fixed with the stud c and conveniently forming part of the contact plate c¹ is a
short arm or offset c which carries a binding post 7 and screw 8 constituting a
second terminal and in this terminal is clamped one end of a length of fusible
wire d' which passes partly around the circular nut c5 and through the hollow
carbon arm e¹.
Upon the same insulating slab 6 and upon the same side thereof but at a corner
diagonally opposite that in which the aforesaid stud c is fixed is provided a second
stud c and duplicate set of parts to which the other end of the lead or conductor d
which passes through a similar insulating plug 62 in that end of the box a is
connected.
In order to set the cut out the two carbon arms are turned into a diagonal
position against the force of the springs
shown by the full lines in Figure
wire d¹ after passing from the first
with their ends nearly in line as
1 and the length of fusible
terminal through the first
carbon arm el is passed through the second arm to the terminal of the

page_text: contact plate c¹ and stud c at the inner end of said arm to which its other end
is clamped by the binding screw and the carbon arms e are thus held in their
diagonal position by the short loop or length of fusible wire extending
between their ends and over which loop di* the total current is necessarily
5 carried.
A similar set of two arms e and coacting parts is arranged within the
chamber B upon the other slab or base 6 and to which the other or lead + or
conductor d which completes the circuit is similarly connected by the studs c of
this set of parts are preferably located in different corners of the box to
those occupied by the arrangement so as to render the insulation of the two
sets of apparatus as perfect as possible.
The action of the apparatus herein before described is as follows:-
So long as the current passing along the leads or conductors d is a normal
one the short length or loop * of the fusible, wire between the ends of the
carbons e will remain intact but upon the current meeting with a troublesome
resistence or the..volume thereof being suddenly increased or if from other cause
undue. heat is generated in the circuit the loop * of fusible wire will become
fused and the carbon arms el will by the action of the springs simultaneously
swing apart into their parallel positions notwithstanding that the fusible loop di
may be coated with a film of oxide the strength of the springs being sufficient
to break said film.
I
1 .
"
The current will thus be effectually broken without liability to flash and the
remaining lengths of fusible wire d by reason of being clamped to the offset
terminals or posts 7 and passed around the circular nuts will in the move-
ments of the arms el to their parallel position be shortened up and their fused
ends drawn into the hollows of the carbon arms e¹ so that no danger can arise
therefrom inasmuch as the arc is shifted from the fusible metal to the carbons e¹
which take up and by reason of their separation break or destroy the same.
By the peculiar arrangement of the two sets of carbon arms el upon insulating
slabs located at opposite sides of the partition the possibility of a work-
man or attendant inadvertently, completing the circuit by a tool in his hand
whilst adjusting the fusible wire is avoided.
When the device is arranged in a vertical position the springs ² may be
dispensed with and the holders e furnished with counterweights to cause the
necessary separation of the carbon arms e¹.
It will be obvious that the details of construction of the device may be other-
wise considerably modified without departing from the spirit of the invention.
By the means herein before described a simple and inexpensive automatic cut
out is obtained which is instantaneous and otherwise highly efficient in its action
whilst possessing other advantages.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed we declare that what
we claim is :-
1. In an electric cut out a pivotally mounted hollow carbon arm through
which passes a length of fusible wire forming part of a lead or conductor means
located at the inner end of said arm for turning the arm on its axis upon the
breaking of the fusible wire said fusible wire at its inner end passing around
an offset or projection so that upon the turning movement of the arm the
severed end of the fusible wire will be drawn into the hollow of the arm sub-
stantially as herein shown and described and for the purpose stated.
2. In an electric cut out two pivotally mounted hollow carbon arms a length
of fusible wire forming part of a lead or conductor passing through said arms
n such manner as to form a loop connecting and holding the outer ends thereof,
means located at the inner ends of said arms for turning the same on their axes
pon the breaking of the fusible wire said wire at its inner ends passing around
offset or projections so that upon the turning movement of the arms the severed

page_text: ends of the fusible wire will be drawn into the hollows of the arms thereby
breaking the arc substantially as herein shown and described and for the purpose
stated.
3. In an electric cut out an insulating slab, a metallic stud fixed at a suitable
point in said slab, a contact plate fixed with the stud, a terminal on said contact
plate adapted to receive one end of a lead or conductor, a holder pivotally mounted
on the stud and there secured by a nut, a hollow carbon arm fitted in said
holder, means for turning the holder and arm into a given position, a second
terminal on said contact plate, a duplicate set of parts and arm located at a
convenient point on said slab and having connected thereto another
end of the lead or conductor, a length of fusible wire passing
from the second terminals of each contact plate around the nuts and
through the hollows of the arms in such manner as to form a loop connecting
and holding the outer ends of the arms against the action of the turning means
so that upon the loop becoming fused the arms will automatically separate and
the ends of the fusible wire will be drawn into the arms thereby breaking the
arc substantially as herein shown and described and for the purpose stated.
4. In an electric cut out a box having a central partition, an insulating slab
fixed on each side of the partition a pair of hollow carbon arms pivotally mounted
upon each slab in suitable positions, a length of fusible wire forming a con-
tinuation of the lead or conductor passing through one pair of said arms and
holding them with their ends in close juxta-position, a similar length of fusible
wire passing through the other pair of arms on the other slab in continuation
of the lead or conductor and means for turning the arms on their axes upon the
breaking of the fusible wire and thereby breaking the arc substantially as herein
shown and described and for the purpose stated.
n
101
1
P
1
1000
WHITE & WOODINGTON,
Birkbeck Bank Chambers, Southampton Buildings, London,
Agents.