AN IMPROVED DUPLEX CUT OUT FOR ELECTRIC CIRCUITS
Year: 1885

page_text: We ROBERT MAJOR BAILY Junr Engineer and ALFRED GRUNDY Electrician
both of Amberley Works Amberley Road Paddington Middlesex do hereby declare
the nature of our invention for AN IMPROVED DUPLEX CUT OUT FOR ELECTRIC
CIRCUITS to be as follows:-
A two way switch of convenient pattern having at the outer ends of its two
blocks (instead of the usual binding screws) two semi-circular grooves cut the
whole length of the blocks.
Facing but insulated from these two blocks is another block of metal reaching
in width to the outer edges of the two blocks. This larger block has a suitable
binding screw for the leading wire, and has on its side facing the two blocks a semi
circular groove similar to and parallel with the grooves in them.
The frame which supports the fusible material of the cut out (which fusible
material may be of any approved kind such as lead wire, tin foil or whatever may
be deemed suitable) is made as follows
Two clamps provided with suitable binding screws for securing in position the
fusible material have each their outer edges of a half round form, and so arranged
as to slide in the grooves of the blocks before mentioned.
These two clamps are mounted the one on two pieces of tube and the other on
two plungers which are acted upon by a spring inside the tube so that the two
clamps are always forced outwards from each other to the full extent of the fusible
material, but are prevented by suitable stops from having a tendency to strain or
rupture that material. The tube or plunger or both are mounted on insulating
material so that the only path for the current is through the fusible material.
The contact between the half round projection of the cut out frame and the semi
circular grooves in the blocks is insured by the outward pressure of the springs on
the plungers.
One or two spare frames being kept ready fitted with the foils or strips of the
desired fusible material all that is necessary on a cut out fusing is to move over the
switch to the second block slide out the frame containing the fused material, alide
in a fresh one and the fusible material in the old frame can be replaced at
leisure.
It is advisable that the fusible material in the frame attached to the second
block of the switch should be a little heavier than the first so that a partial short
circuit (unless it is dangerously bad) shall not entirely stop the lighting.
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page_text: A
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An Improved Duplex Cut Out for Electric Circuits.
ROBERT MAJOR BAILY Junior Engineer & ALFRED GRUNDY Electrician both of
Amberley Works Amberley Road Paddington Middlesex 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:-
t
The object of this invention is to provide a ready method of changing the fuze
or foil of a safety junction or cut out after it has been fuzed or ruptured by the
passage of the current or by accident and at the same time to provide a sub-
stantial connection, for the spare fuze or foil while the damaged one is being
replaced.
A two way switch 6 Fig. 1 is fitted to a suitable base a. a. and provided with a
lever g. which can make contact with either of the contact pieces c. d. there is a
suitable binding screw or clamp at e for one of the leading wires The contact
pieces c. d. have (instead of the usual binding screws) a groove, preferentially half
round as at d Fig. 4 but it may if desired be of a V shape or any other suitable
form.
•
Fixed to the base board a convenient distance from c. d. is a block of metal ƒ
extending in width' as far as the outsides of the contact points c and d and having
on its underneath side a groove similar to and parallel with those in the pieces c
and d (see c. Fig. 4).
This piece has also a suitable arrangement for connecting the leading wire or
other conductor The part of may if desired be slightly tapered towards its outer
ends so as to ensure a wedge like contact with the parts shewn in Figs. 2 & 3
which we will now explain.
In Figs. 2. 3 and 4. a. is a solid piece of metal the outer edge of which is made
to fit mechanically true in the groove c. Fig. 4 whether that groove be half
round or otherwise b. is also a piece of metal its outer edge fitting in the
groove d. Fig. 4.
c. c. Figs. 2 & 3 are small plates of metal fitted to the blocks a. b. by screws. 8. 8.
and carrying a piece of lead wire tin foil or other suitable or approved material
these blocks or clamps are mounted facing each other the one on two pieces of
tube d. d. Fig. 3 and the other on two plungers e. e. which are acted upon by a
spring shewn inside one of the tubes d. Fig. 3 so that the two blocks a and b are
always forced outwards from each other to the full extent of the fusible material
but are prevented by a pin or other device passing through the tubes d. d. from
having a tendency to rupture or tear.that material. The plungers e. c. or the tubes
d. d. or both are suitably insulated from a and b so that the whole of the current
must pass through the fusible material connected between a and b,
The contact between the blocks a. b. Figs. 2 and 3 and the parts c. d and f
Fig. 1 is ensured by the outward pressure of the springs on the plungers assisted if
necessary by the wedge shape of the block a as in Fig. 2 sliding in the tapered
groove in Fig. 1.
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Or the frame for the fusible material may be made as in Fig. 2 the parts a
and b being held in position by solid bars f. f. The contact is in this case dependent

page_text: on the tightening effect of the wedge shaped block a Fig. 2 or the block b Fig. 2.
may also be of wedge shape if found necessary or convenient.
One or two spare frames being supplied with each instrument and kept fitted
with foils or whatever material may be used and the bar g. of the switch see
Fig. 1 being say on the contact point c should the cutout connected with c fuze, the
switch is immediately moved on to d. the frame containing the old fuze is slid out
at the side, a spare one put in and the old foil can be renewed at leisure or when
the frame has bad time to cool..
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 of parts forming a duplex arrangement for safety fuzes in an
electric circuit in which the fuzed parts can be readily changed or replaced.
2. The combination of these parts in such a manner that the connection for
cutting out the fuzed part shall be at all times in good electric contact and of
sufficient stability to carry the current for which the instrument is designed.
3rd A duplex cutout for electric circuits as herein before described and set forth.
Dated this 1st day of March 1886 ·
R. M. BAILY, JUNR.
A. GRUNDY.