SAFETY FUSES FOR USE IN ELECTRIC CIRCUITS MENTS IN FITTINGS FOR CARRYING
Year: 1884

page_text: JE BICOCCUS.
I, GEORGE CAMERON SILLAR of 112, Belvedere Road, Lambeth, in the County
of Surrey, Engineer do hereby declare the nature of my invention for IMPROVE-
"
SAFETY FUSES FOR USE IN ELECTRIC CIRCUITS
MENTS IN FITTINGS FOR CARRYING "
to be as follows:-
"
My Invention relates to improvements in the construction of fittings to carry
safety fuses" for use in electric circuits and has for its object the production of
a simple and at the same time highly efficient fitting, capable of being rapidly
replenished with new "fuses" when the one in use has been melted and of
automatically adjusting itself to fuses of various gauges.
In carrying out my Invention I fix, on a base made of slate or other suitable
insulating material, which I hereinafter refer to as the "base," two or more pieces
of metal, which pieces are hereinafter referred to as the "terminals."
These "terminals" I make of novel form, consisting principally of a bolt & nut
for clamping it to the insulating base, the head or upper part of which bolt is made
preferably of a cylindrical form and of a suitable length for purposes to be herein-
after described. Through the lower end of this bolt and at a suitable distance from
the point and at right angles to its axis, I drill a hole of suitable size, for the
introduction of the end of the conductor forming the circuit & through the centre
of the bolt, parallel to its axis, I drill and tap a hole of suitable size to which is
fitted a screw of suitable length, hereinafter referred to as the "binding screw,"
for the purpose of firmly fixing the above mentioned conductor to the bolt, the
head of which screw forms a stop for the outer portion of the said terminal, next
hereinafter described.
On to the outside of the preferably cylindrical head of the bolt, having the same
axis and free to move in a plain parallel to the axis only is a preferably cylindrical
cap, so constructed that when the lower edge of the cap coincides with the lower
edge of the bolt head, a slot or groove in the cap, cut at right angles to its axis,
exactly coincides with a similar slot or groove in the head of the bolt. It is into
these grooves that the "fuse," preferably a piece of lead wire which I shall herein-
after refer to as the fuse, is inserted. This cap, is of such a convenient length as
to allow of a spiral compression spring being inserted between and acting upon
the upper end of the bolt and the inner or upper end of the cap, which portion of
Pier 71

page_text: the cap has a hole drilled through it, to allow of the free passage of the
screw
binding
hereinbefore mentioned, the head of which forms the stop for the cap, to
limit the action of the above mentioned compression spring. The "fuse" is thus
held in metallic contact with the metal of the terminal by means of the shearing
strain brought to bear upon them by the action of the compression spring & when
the terminals are respectively connected to the ends of the wire connected with a
source of electricity, the "fuse" forms part of the electrical circuit.
Between and attached to or fitting in to grooves in the two caps of any one pair
of terminals, I sometimes place a connecting bar or strip of any suitable insulating
or insulated material as vulcanite or slate which being pressed upon by the finger
overcomes the pressure of the springs and allows the "fuse" to be readily removed.
or inserted into the grooves.
I sometimes however, as an alternative, modify the above design by substituting
in the place of the two caps, two sliding sleeves and instead of the two springs
acting directly upon the caps, substituting in place thereof a single compression
spring of suitable shape, fixed between the two terminals and acting upon the
upper side of the base to which the terminals are fixed and the under side of the
connecting bar, thereby performing the same function as the two spiral compression
springs in the previously mentioned arrangement.
I may sometimes also, in place of the spring, above mentioned employ a running
nut, acting upon the upper or lower end of the sleeve working on a screw cut on
the head of the terminal, as a means of clamping the ends of the "fuse" in which
case, when the grooves are coincident, the upper or lower edge of the bolt head
would project above or below the upper or lower edge of the sleeve or cap, by the
thickness of the nut used.
I attach the cover to the base by means of a "bayonet joint" or other suitable
connection, so as the more easily to remove it to replace the "fuse." I also some-
times make the top or cover of glass or other transparent material, so that the
condition of the fitting or "safety fuse" may be readily observed without removing
the cover.

page_text: Improvements in Fittings for Carrying Safety Fuses for Use
in Electric Circuits.
I, GEORGE CAMERON SILLAR of 112 Belvedere Road, Lambeth, in the County
of Surry, Engineer, do hereby declare the nature of my invention for IMPROVE-
MENTS IN FITTINGS FOR CARRYING SAFETY FUSES FOR USE IN ELECTRIC CIRCUITS
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
"
My Invention relates to improvements in the construction of Fittings to carry
Safety Fuses" for use in Electrical circuits and has for its object the production
of a simple and at the same time highly efficient fitting capable of being rapidly
replenished with a new "Fuse" when the one in use has been melted and of
automatically adjusting itself to fuses of various gauges.
In the accompanying drawings Fig. 1 & 2 are elevations and Fig. 3 is a plan of
the fitting herein described.
In carrying out my Invention I fix on a base "A" made of slate or other
insulating material two or more pieces of metal or other conducting material
preferably of brass which two pieces hereinafter referred to as the "Terminals
are suitably connected to the source of Electricity, and are when in use joined
together by means of the fusible metal. These terminals I make of novel form
each consisting principally of a bolt "B" (Fig. 1 & 2) and nut "C" for clamping
it to the insulating base the head or upper part of which bolt is made cylindrical
and of a suitable length for purposes to be hereinafter described.
Through the lower end of the bolt "B" (Fig. 2) and at a suitable distance from
the point and at right angles to its axis I drill a hole "D" of suitable size for the
introduction of the ends of the conductor forming the circuit and through the
centre of the bolt "B" parallel to its axis, I drill and tap a hole of suitable size
to which is fitted a screw "E" of suitable length hereinafter referred to as the
binding screw" for the purpose of firmly fixing the above mentioned conductor to
the bolt, the head of which screw "C" forms a stop for the outer portion of the
said terminal hereinafter described.
"
On the outside of the cylindrical head of the bolt "B" having the same axis
and free to move in a plain parallel to the axis only is a cylindrical cap "F" 80
constructed that when the lower edge of the cap coincides with the lower edge of
the bolt head, a slot or groove in the cap cut at right angles to its axis exactly
coincides with a similar slot or groove in the head of the bolt into which grooves.
the "Fuse" is inserted.
This cap is of such a convenient length as to allow of a compression spring "G"
being inserted between and acting upon the upper end of the bolt "B" and the
inner and upper end of the cap "F" which portion of the cap has a hole drilled
through it to allow of the free passage of the binding screw "C" herein before
mentioned the head of which forms the stop for the cap "F" to limit the action
of the above mentioned compression spring "G."
On to each base which is enclosed in a suitable cover "H" I fix two or more
of these terminals for one or more circuits the two open ends of any particular

page_text: circuit being capable of being respectively connected to any one pair of terminals
the circuit being completed through the "Fuse" the ends of which are firmly con-
nected to the terminals by the shearing strain brought to bear upon them by the
action of the compression spring tending to destroy the coincidence of the grooves
in the cap and bolt head into which the ends of the "Fuse" have been inserted.
Between and attached to the two caps F F" (Fig. 4) of any one pair of
terminals, I sometimes place a connecting bar " "I" of any suitable insulating or
insulated material which being pressed upon by the Finger or in any other
convenient manner overcomes the pressure of the springs and allows the fuse to be
readily removed or inserted into the grooves.
"1
I may however as an alternative modify the above design by substituting in the
place of the two caps, two sliding sleeves "J" "J" (Fig. 5) and instead of the
two springs acting directly upon the cap substituting in place thereof a single
compression spring "K" of suitable shape, fixed midway between the two terminals
and acting upon the upper side of the base "A" to which the terminals are
fixed and the underside of the connecting bar "I" thereby performing the same
function as the two spiral compression springs in the previously mentioned
arrangements.
I may also in place of the springs above mentioned employ a running nut "L"
(Fig. 6 & 7) upon the upper or lower end of the sleeve working on a screw, cut on
the head of the terminal "B" as a means of clamping the ends of the fuse in
which case when the grooves are coincident the upper or lower edge of the bolt
head "B" would project above or below the upper or lower edge of the sleeve or
cap "F" by the thickness of the nut used.
I also attach the cover" H" (Fig. 1 & 2) to the base A" by means of a button-
hole, or bayonet joint or other suitable method of connection so as the more easily
to remove it to replace the fuse. I also sometimes make the top or cover of glass
or other transparent material so that the condition of the fitting or safety fusé
may be readily observed without removing the cover.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is
1st The holding of the ends of the fuse by means of coincident holes or grooves
in two or more pieces of conducting material tending to move in opposite
directions.
2nd The combination in one of a terminal for attachment to the circuit
conductor, means for attachment to the base or bed of the fitting and a holder for
attachment to the fuse substantially as described.
Ament 100K