Year: 1888

page_text: 1 JOSEPH GRACE SMITH CUNNINGTON of 31 King Street Covent Garden in the
County of Middlesex Electrical Engineer do hereby declare the nature of this Invention
to be as follows:-
The object of my Invention is to provide a fusible device which is very efficient
and is readily put in place and removed by unskilled persons and a further object is
to prevent the use of such a device unfitted for the particular circuit with which it is
to be used.
According to my Invention a fusible conductor is mounted on a carrier of insulating
material and is in electric contact preferably by means of solder with contact pieces
which are fixed to the said carrier and are preferably made of copper presenting a
considerable surface. The two portions of the circuit to be joined by the device arc
provided with contact pieces preferably constituted by clips held in a slot in a suitable
mounting so that they grasp and bear on the aforesaid contacts on the carrier and so
that the carrier can be readily slidden into place and readily removed to complete the
circuit. The carrier is provided with a projecting portion to be grasped by the person
using it. The contacts in the mounting and the slot in which they are situated
correspond in size only with the contact pieces of a fusible conductor fitted for
the particular circuit so that only a fusible conductor fitted for the circuit can
be used.
The devices may be used singly or in any desired combinations of two or more
Dated this 12th day of April 1888.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C.,
Agents.

page_text: An Improved Fusible Device for Protecting Electric Circuits.
I JOSEPH GRACE SMITH CUNNINGTON of 31 King Street Covent Garden in the
County of Middlesex 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 objects of my Invention are to provide a fusible device which is very efficient
and is readily put in place and removed by unskilled persons and by which the use of
such a device unfitted for the particular circuit with which it is to be used, and which
it is to protect, is prevented. The essential feature of the Invention is to provide in
connection with the electric circuit to be safeguarded a holder or receptacle fitted to
receive a fusible device which is fused when the amount of current which is the limit
for that particular circuit is exceeded but which will not receive a fusible device which
will not fuse under that condition.
I will explain with reference to the accompanying drawings what I consider the
best means of carrying my Invention into effect premising that I do not limit myself
to the precise details which I shall describe. Figure 1 is a plan and Figure 2 a
vertical section of a device constructed according to my Invention, Figures 3 and 4
are corresponding views of a similar device for a larger current. Figure 5 is a side
view and plan of the plug shewn in Figures 1 and 2 for carrying the fusible conductor.
and Figure 6 is a longitudinal section and plan of underside of the modification in
the form of plug which is shewn in Figures 3 and 4. In Figures 2 and 4 the plugs
carrying the fusible pieces are removed and in Figures 1 and 3 one of the said plugs
is shewn in place and the other removed. The plug is constituted by a fusible
conductor A (Figures 5 and 6) mounted on a carrier B of insulating material and the
said fusible conductor is in electric contact with contact pieces C. C. which are fixed
to the said carrier B and are preferably made of copper presenting a considerable
surface. The fusible conductor A may be fixed in the carrier by being soldered to
the contact pieces C or by being otherwise made to have good contact with the said
contact pieces for example as shewn in figure 6 the conductor may be pinched in
between the contact pieces (and carrier B by the screws bb. The two portions of
the circuit to be joined by the device are connected by binding screws de or other-
wise with contact pieces FF preferably constituted by clips or embracing pieces held
in a slot G in a suitable mounting H so that the said clips or embracing pieces grasp
and bear on the aforesaid contact pieces C. C. on the carrier B and so that the plug
can be readily slidden or put into place and readily removed to complete or interrupt
the circuit. The carrier B may be provided with a projecting portion b² (Figure 5)
or with some suitable equivalent therefor to be grasped by the person using the
device. The contacts F F in the mounting and the slot G in which they are situated
correspond in size only with the contact pieces C and carrier B having a fusible
conductor fitted for the particular circuit so that only a fusible conductor fitted for
the circuit can be used my principal object being to prevent a fusible device of a
large size being used when a small one should be used.
jº

page_text: It will be seen by referring to the drawing that the carrier B and contact
pieces C with the fusible conductor A shewn in Figures 3. 4 and 6 is not suited for
use with the device shewn in Figures 1 2 and 5 and vice versa.
The Invention is not limited to making the plugs and carriers of varying widths
as the same object may be otherwise obtained for example by making them of
varying lengths as shewn in Figures 7 to 10 so that a plug carrying a fusible
conductor not suited to the circuit does not bridge across or make contact with the
contact pieces of the carrier or cannot be inserted thereinto. Figure 7 shews a
plan of the mounting or holder and Figure 8 an elevation of the plug carrying a
fusible conductor suited to one circuit and Figures 9 and 10 are similar views of the
mounting or holder and plug for another circuit. It will be seen that the lengths
of plugs and the distance between the contact pieces of the carrier are such that
the plugs carrying the fusible conductors suited to a large current cannot be placed
in carriers fitted to a circuit for a small current, and this will generally be sufficient
although it will be readily understood that the plugs and holders or mountings may
be so proportioned that not even a fusible conductor suited for a small current can
be placed in a circuit which requires a fusible conductor for a larger current.
The devices may be used singly or in any desired combinations of two or more a
combination of two being illustrated by the drawings.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed I declare that what I
claim is-
1. Fusible devices and their fittings for protecting electric circuits the said
devices and fittings being arranged or constructed substantially as hereinbefore
described so that a fusible device cannot be used unfitted for the circuit which it
is to protect.
2. The particular constructions of fusible devices and their fittings for protecting
electric circuits the said devices and their fittings being constructed as herein before
described and shewn respectively in figures 1. 2 and 5 in figures 3. 4 and 6 and in
Figures 7. 8. 9 and 10 of the accompanying drawings.
Dated this 14th day of January 1889