Improvements in High Tension Electric Switches.
Year: 1898

page_text: Date of Application, 3rd Feb., 1898
17th Dan
1000
PROVISIONAL SPECIFICATION.
Improvements in High Tension Electric Switches.
EDWARD WOODROWE COWAN, Hart Hill, Woodville Road, Bowdon, Cheshire,
Civil Engineer, and ALFRED STILL, Bow Green Farm, Bowdon, Cheshire, Civil
Engineer, do hereby declare the nature of this invention to be as follows:-
Our improvements consist of a special design of high tension switch of that
pattern generally known as the Hatchet type. Our improved switch has the
advantage of being double break, very compact, protected in every part so that
dangerous accidental contact on the part of the manipulator of the switch is
practically impossible, and at the same time so designed that the formation of a
destructive arc is rendered impossible with pressures up to two or three thousand
volts.
We obtain the advantages enumerated above by placing the contacts to which
the cables are connected within recesses in the base on which the switch is
mounted, and fixing guard plates or covers of incombustible and non-conducting
material over the front of the recesses, with slots or holes in them just large
enough to allow the connecting tongues on the moveable part of the switch to
pass. In a single pole switch there are two recesses in which the contacts are
placed, and two connecting tongues carried by the moveable part of the switch
On the front of the base are fitted bonnets
and joined together by a metal bar.
or hoods of porcelain or other non-conducting and incombustible material which
may, or may not be extensions of the guard plates referred to above. Over each
recess one of these bonnets is placed, and between the two a slot is cut in the
base of the switch through which passes a partition of glass, porcelain, or other
non-conducting and incombustible material which is fixed to the moveable part
of the switch between the two connecting tongues referred to above.
We prefer to make the switch spring break, either with or without loose
handle. The action of our improved switch in breaking a high tension circuit
is then as follows:-the handle is pulled over by the attendant, and any arc
which may tend to be formed at break is ruptured because the narrow slots in the
covers of the recesses, and the rapid break, if spring break, as we prefer to make
it, tend to extinguish it, and, further, the length of air space between the con-
tacts and the contact tongues on the connecting piece is such that, under ordinary
conditions, an are cannot be maintained across it by two or three thousand volts.
The tendency of the are to follow another path between the contacts is prevented
by the sides and top of the bonnets or hoods referred to above, and also by the
partition which, in all positions of the switch, separates the contact tongues.
Our invention consists in the combination of the different points referred to
above, and also the arrangement of hoods over the contacts and the arrangement
of the partition as applied to a high tension switch.
T 1
1808

page_text: Son Electric Switches.
EDWARD WOODROWE COWAN, of Hart Hill, Woodville Road, Bowdon, Cheshire,
Civil Engineer, and ALFRED STILL, of Bow Green Farm, Bowdon, Cheshire, Civil
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:-
Our improvement consists of a special design of high tension switch of that
pattern generally known as the Hatchet type. Our improved switch has the
advantage of being double break, very compact, protected in every part so that
dangerous accidental contact on the part of the manipulator of the switch is
practically impossible and at the same time is so designed that the formation of
a destructive arc is rendered impossible with pressures up to two or three thou-
sand volts. We obtain the advantages enumerated above by placing the contacts
to which the cables are connected within recesses in the base on which the switch
is mounted and fix covers or guard plates of incombustible and non conducting
material over the front of the recesses, with slots or holes in them just large
enough to allow the connecting tongues on the moveable part of the switch to
pass. In a single pole switch there are two recesses in which the contacts are
placed, and two connecting tongues carried by the moveable part of the switch,
and joined together by a metal bar. On the front of the base are fitted bonnets
or hoods made of porcelain or other incombustible material which may or may
not be extensions of the guard plates referred to above. Over each recess one of
these bonnets is placed, and between the two a slot is cut in the base of the switch
through which passes à partition of glass, porcelain or other non-conducting and
incombustible material which is fixed to the moveable part of the switch between
the two connecting tongues referred to above. We prefer to make the switch
spring break, with or without loose handle. The action of our improved switch
in breaking a high tension circuit is then as follows:-The handle is pulled over
by the attendant, and any are which may tend to be formed at break is ruptured
because the narrow slots in the covers of the recesses, and the rapid break-
if spring break, as we prefer to make it,--tend to extinguish it, and further,
the length of air space between -the contacts and the contact tongues on the con-
necting piece is such that, under ordinary conditions, an arc cannot be main-
tained across it by two or three thousand volts. The tendency of the arc to
follow another path between the contacts is prevented by the sides and top of the
bonnets or hoods referred to above, and also by the partition which, in all post-
tions of the switch separates the contact tongués.
11
In Figs. I and II of the accompanying drawings, our improved switch is shown.
These drawings are of a single pole switch. The contacts C are mounted within
the cells or recesses R which we prefer to make of porcelain. These cells or
recesses are bolted or otherwise fixed to the base of the switch.
The hoods H, which we also prefer to make of porcelain or stoneware are
made in one piece with the guard plates V; these guard plates having narrow
slots K in them, just large enough to allow the connecting tongues T to pass
through to the contacts C. The connecting tongues, T, are mounted on, but
insulated from the moveable part of the switch L L. The connecting tongues 4
are joined by a flat metal bar B. Between the two bonnets is the slot S through
which the partition P can pass when the switch is closed. The partition is fixed
to the central lever 1.
When operating the switch the attendant pulls over the lever 7 by means of the

page_text: handle h. The levers L L, which carry the connecting tongues do not follow
the
movement of the lever until the end of the slot E comes
into contact with the bolt b, when the levers L L commence to
move with the centre lever. When the connecting tongues are out of, or
nearly out of the contacts, the spring D comes into operation. This spring is
at this point in tension as one end of it is fixed to the central lever and one end
to the bolt joining the side levers. The effect of the contraction of the spring
is to draw the side levers rapidly towards the central lever, and this arrangement
thus provides a spring break. We protect all parts of the switch carrying high
pressure current so that the operator cannot accidentally receive a shock.
Having now particularly described and ascertained the nature of our said in-
vention, and in what manner the same is to be performed, we declare that what
we claim is :-
1. The construction of a high tension switch with contacts in recesses and
with slotted guard plate in combination with hoods or bonnets arranged sub-
stantially in the manner described and shown.
2. The construction of a high tension switch with a moveable partition in
combination with hoods or bonnets arranged substantially in the manner described
and shown.
3. The construction of a high tension switch substantially as described and
shown on accompanying drawing Figs. I and II.
Dated this Second day of November 1898