Improvements in Safety Fuses for Electric Circuits.
Year: 1899

page_text: Date of Application, 10th Aug., 1899
1000
Improvements in Safety Fuses for Electric Circuits.
I, ERNEST THOMAS GOSLIN, of St. David's, Mount Nod Road, Streatham, in the
County of London, Electrical Engineer, do hereby declare the nature of this
invention to be as follows:-
My invention relates to safety fuses for electric circuits and has for its object
to provide improved means for obviating the formation of an are as now so fre-
quently happens when a fuse "blows."
"
According to my invention I arrange that the safety fuse should support a
portion of the conductor through which the current passes in such a manner that
should the fuse "blow the part of the conductor supported by the fuse will drop
and so break the circuit at a point independent of that where it is broken by the
blowing of the safety fuse.
In a suitable arrangement for carrying out my invention the portion of the
conductor which is made movable is arranged in a tube of porcelain or other
suitable non-conducting material supported in a vertical position in a holder by
a strap or stirrup at the lower end which forms the safety fuse and which is con-
nected with the conductor in the said tube and also with a ring or other part
through which the current flows.
The connection between the said movable rod and the circuit cable or wire is
effected by connecting the latter to a plug terminating in a male cone which
fits into a corresponding female cone on the adjacent end of the movable conduct-
ing piece, the said cone being of conducting material and having at its point
a spring contact piece which is normally depressed inside the cone but which when
the movable portion of the conductor drops away from it, is pushed outwards
and forms the last point of contact between the permanent portion of the con-
ductor and the said movable portion thereof, any spark which is produced when
the circuit is broken at this point acting upon the said movable point, which is
preferably of zinc, and thereby avoiding injury to the contact surface of the cone.
The cone is acted upon by a spring arranged in a suitable chamber in
which the cone is also arranged, the said spring, when the holder carrying the
movable portion of the conductor is in position, being compressed, this arrange-
ment of spring being provided to ensure a good electrical contact between the
cones and also that if the fuse blows there shall be sufficient pressure to
quickly release the tube containing the movable portion of the conductor thus
breaking any are that may be set up across the fuse terminals.
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1
101
1800
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.

page_text: I, ERNEST THOMAS GOSLIN, of St. David's, Mount Nod Road, Streatham, 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:-
My invention relates to safety fuses for electric circuits and has for its object
to provide improved means for preventing a violent explosion and obviating the
formation of an arc as now so frequently happens when a fuse "blows" under
high pressure.
According to my invention I arrange that the safety fuse should support a
portion of the conductor through which the current passes in such a manner that
should the fuse blow" the part of the conductor supported by the fuse will drop
and so break the circuit at a point independent of that where it is broken by the
blowing of the safety fuse, and that owing to the above and to the short length
of the safety fuse employed a violent explosion is prevented.
In a suitable arrangement for carrying out my invention the portion of the
conductor which is made movable is arranged in a tube of porcelain, or other
suitable non-conducting material supported in a vertical position in a holder by
a strap or stirrup at the lower end which forms the safety fuse and which is con-
nected with the conductor in the said tube and also with a ring or other part
through which the current flows.
The connection between the said movable rod or conductor and the
circuit cable or wire or other conductor is effected by connecting the
latter to a plug terminating in a male cone which fits into a corre-
sponding female
cone on the adjacent end of the movable conducting
piece, the said male cone being of conducting material and having at its point
or apex a spring contact piece which is normally depressed inside the female cone
but which when the movable portion of the conductor drops away from it, is
pushed outwards and forms the last point of contact between the permanent por-
tion of the conductor and the said movable portion thereof, any spark which is
produced when the circuit is broken at this point acting upon the said movable
point or spring contact which is preferably of zinc or carbon, thereby avoiding
injury to the contact surface of the male cone.
The male cone is acted upon by a spring arranged in a suitable chamber in
which the said cone is also arranged, the said spring,, when the tube or holder carry-
ing the movable portion of the conductor is in position, being compressed, this
arrangement of spring being provided to ensure a good electrical contact between
the cones and also that if the fuse "blows" there shall be sufficient pressure to
quickly release the tube containing the movable portion of the conductor thus
breaking any are that may be set up across the fuse terminals.
To enable my invention to be fully understood I will describe it by reference
to the accompanying drawings in which:-
:-
Figure 1 is a sectional side elevation shewing my improved safety fuse applied
to a double break switch:
Figure 2 is a sectional rear elevation of part of the same:
Figure 3 is a sectional plan of the switch.
Figure is an inverted sectional plan of the same.
Figure 5 is a horizontal section on the line 5-5, Figure 1. with the upper
part or cover of the switch removed: and
Figure 6 is an elevation of one of the contacts of the switch.

page_text: a is the base or fixed part of the switch carrying the contacts b, c forming
the terminals of an electric circuit, one of which contacts is illustrated by
Figure 6 and is the movable part of the switch hinged to a bracket e on the
base a, the said part d being provided with contacts f,.g to engage the con-
tacts b, c respectively and with a handle to allow of its manipulation; all these
parts are of known construction.
is the movable portion of the conductor and j is the safety fuse which nor-
mally supports the part i, the said part and the fuse j being carried by the
part of the switch; the fuse j is shewn as consisting of a series of strips form-
ing a kind of stirrup or strap connected at its centre to the conductor and at
its ends to the part & carrying the contact f. 7 is the tube of porcelain or other
non-conducting material enclosing the conductor and supported in a vertical
position by the fuse j at its lower end. The part kis advantageously in the form
of a ring carried at the lower end of a tubular casing of non-conducting mate-
rial in which the tube carrying the conductor i is located. m is the plug
carrying the male cone » and in electrical connection with the contact g as shewn
clearly in Figure 1, the said plug and cone being located in a chamber m¹ formed
in a part m³ carrying the contact g and supported at the upper end of the
casing ; o is the female cone on the adjacent end of the conductor i into which
cone the said male conen fits, the space between the two cones when separated as
hereinafter described forming the break in the circuit independent of that where
it is broken by the blowing of the safety fuse. is the zinc or carbon spring
contact piece at the point of the cone and g is the spring arranged in the
chamber m¹ for securing a good contact between the cones and o.
is a cap
of insulating material protecting the plug m.
The operation of the improved device is as follows, that is to say assuming the
fuse to have "blown" the conductor then being no longer supported will
drop down out of the casing, breaking the contact between the cones n and o
the spring contact piece being pushed upward by its spring so as to form the
last point of contact with the cone n so that any spark which is produced when
this contact is broken will act upon the said contact piece thereby avoiding injury
to the contact surface of the said cone ». The spring in addition to maintain-
ing good contact between the cones n and also ensures that when the fuse
blows there shall be sufficient pressure to quickly release the conductor i thus
breaking any are that may be set up between the fuse terminals.
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is a tube supported between the arms of the bracket e for receiving the tube 7
and conductor i and for guiding the same clear of the bracket e, the said tube
being suspended by the bracket e by means of the flange and being furnished
with a net or rubber coverings at the bottom to prevent the tube 7 and con-
ductor i falling through.
Instead of allowing the tube / carrying the conductor i to drop clear of the
casing when the fuse "blows" as described I can arrange it to drop a certain
distance only within the said casing and for this purpose I enlarge the central
opening of the casing and provide the tube 7 near its upper end with a flange
or other projection or projections whereby the said tube will fall until the said
flange or the like comes into contact with the ring and remain suspended.
Although I have described my improved safety fuse in connection with a double
break switch, it can, as will be obvious, be arranged independently thereof and
at any suitable part of an electric circuit.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what
I claim is
1. In a safety fuse for electric circuits the combination with the fuse proper
of a portion of the conductor through which the current passes, the said fuse
being arranged to support the said portion of the conductor in such a manner that
should the fuse "blow" the conductor will drop and break the circuit at a point

page_text: independent of that where it is broken by the "blowing" of the fuse, substan-
tially as described.
2. In a device of the kind described in the preceding claiming clause arrang-
ing the fuse in the form of a stirrup attached at its ends to a fixed portion of
the circuit conductor and forming the connection between the movable conductor
and the other portion of the circuit conductor by means of a plug having a male
cone fitting a female cone on the said movable conductor with a spring contact
arranged between the said cones, substantially as, and for the purpose, described.
3. In a device of the kind described in Claims 1 and 2 the combination with
the plug carrying the male cone of a spring, substantially as, and for the pur-
pose, described.
4. The improved safety fuse constructed and arranged, substantially as herein-
before described and illustrated in the accompanying drawings.
Dated this 10th dow of V. 1000
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.