IMPROVEMENTS IN OR APPLICABLE TO SWITCHES OR CIRCUIT-CLOSERS FOR ELECTRICAL CONDUCTING APPARATUS
Year: 1884

page_text: "
I JOHN HENRY HOLMES, of Newcastle-on-Tyne in the county of Northumberland,
Electrician do hereby declare the nature of my said invention for "IMPROVEMENTS
IN OR APPLICABLE TO SWITCHES OR CIRCUIT-CLOSERS FOR ELECTRICAL CONDUCTING
APPARATUS," to be as follows:-
The object of the improvements is to prevent the formation of destructive “arc'
when the current is broken by means of a switch or other arrangement.
"
So far as I am aware in switches hitherto inade there has been a fast connection
between the handle for moving the contact piece, consequently although there may
be a trigger spring and tumbler or spiral spring to prevent the switch being left in
any position other than in perfect circuit or entirely broken circuit, yet an arc will
form if the handle be slowly turned for the purpose of breaking the circuit.
My invention consists in an arrangement of switch which allows the contact
piece or a portion of it by the influence of an independent force such as that of
a spring or weight to move through a certain distance independently of the handle.
The spring or weight is so arranged as to tend to keep the movable contact piece
in the "off" position, but on turning the handle to complete circuit the contact
piece is moved in opposition to the force of the spring or weight and is kept in the
on" position by a frictional or mechanical device.
On turning the handle in the reverse direction to break circuit its first action is
to release the contact piece from the frictional or mechanical device and thus allow
it to fly back suddenly under the influence of the spring or weight, thus causing
the circuit to be broken so quickly that a dangerous are has practically no time
to form
As an example of an apparatus made upon this principle I will describe an
experimental circuit closer on this principle made by me. Upon the axis of the
bandle swivels the connecting bar or contact piece. A spring keeps this in the
"off" position against stops when not prevented by force or held in the friction
catches hereafter described. The two contacts consist each of two metallic jaws
having a tendency to close towards each other but with their lips or outward ends
facing the contact bar further apart. When the bar is forced between these they
spring sufficiently apart to admit it and act as a frictional contact holding the bar
against the force of its spring. On the handle is a disc holding the contact bar in
place and having a projecting pin or flange at right angles forming a sort of crank
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page_text: pin which when standing in a direction at right angles to the axis of the bar stands
clear of the bar and can rotate through thirty degrees of a circle in each direction
before coming in contact with the bar.
The cover holding the disc down and the box in which the contact pieces are
situated are both or at least the box preferably formed of pressed flint glass. The
object in forming them or it of this material is that the latter is very cheap, can
be formed into almost any required shape with little difficulty, looks well, is easily
kept clean, is incombustible and is an admirable non-con-luctor. It therefore forms
an excellent material for cases for switches, circuit-closers and other electrical
mechanisms of similar sort such for instance as cut-outs.
In using the above described switch if the circuit be broken and has to be
formed, the handle is turned, the crank pin pressed against the contact bar and the
ends of the latter forced between the frictional contact pieces or pairs of jaws and
there held. To break the circuit the handle is turned the reverse way, the "crank
pin" comes against the contac: bar on the opposite side of its point of rotation to
that where it pressed it before. It forces the bar ends out from the frictional
catches and the bar the instant it is free from the catches is suddenly drawn away
by its spring from the contact jaws no matter how slowly the handle travels.
A similar arrangement can be applied to the various kinds of switches, the main
points being that the handle must always push not pull or hold, and the spring or
weight must be arranged to break the contact or draw the bar quickly away after
contact is broken inst ad. of that duty being performed by the handle.

page_text: I, JOHN HENRY HOLMES, of Newcastle-on-Tyne, in the county of Northumberland,
Electrician do hereby declare the nature of my said invention for "IMPROVEMENTS
IN OR APPLICABLE TO SWITCHES OR CIRCUIT CLOSERS FOR ELECTRICAL CONDUCTING
APPARATUS" and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
The object of the improvements hereinafter detailed is to prevent the formation
of destructive "arc," when tho electric current is broken, by means of a switch or
other arrangement.
In switches as hitherto designed there has so far as I am aware, always been
a continuous sliding contact during action, or a fast connection between the handle
for moving the contact piece, and the said contact piece, consequently although
there may be a trigger spring and tumbler or spiral spring to prevent the switch:
being left in any position other than in perfect circuit, or entirely broken circuit,
yet a destructive are has been formed when the handle was slowly turned for the
purpose of breaking the circuit.
With the object of overcoming this drawback, I have designed an arrangement
of switch which allows the contact piece or a portion of it by the influence of an
independent force, such as that of a spring or weight, to move through a certain
distance independently of the handle.
The spring or weight is so arranged as to tend to keep the movable contact piece
in the "off" position, but on turning the handle to complete circuit the contact
piece is moved in opposition to the force of the spring or weight, and is kept in the
"on" position by a frictional or mechanical device.
On turning the handle in the reverse direction to break circuit, its first action is
to release the contact piece from the frictional or mechanical devices, and allow.
it to fly back suddenly under the influence of the spring or weight, thus causing.
the circuit to be broken so quickly that a dangerous are cannot be formed.
Figs. 1 and 2 shew elevation partly in section and plan of a small sized
apparatus, and
Fig. 3 and 4 elevation and plan of a large size apparatus.
Referring to Figs. 1 and 2, the apparatus consists of an outer covering or box of
any suitable material, enclosing the mechanism, having a lid overlapping the disc
described further on, and from the centre of which a handle A projects, whereby
the connection can be made or broken as required. The axis of this handle is
supported in a bearing a at the bottom of the box. The connecting bar or contact
piece B swings loosely on the axis, a spring O'keeps the bar B in the "off" position
against stops DD when not prevented by force, or when the connecting bar is not
held tight in the friction catches or contacts E E. These contacts consist each of
two flat metallic plates or jaws laid upon each other and held together at one end
by screws, their other ends ee which face the contact bar B are somewhat wider
apart so as to admit of the bar being forced in between them, and held tightly;
they thus act as a frictional contact holding the bar against the force of its spring C
which is also in such a position as to have little power on the bar.
Above this arrangement the axis of the handle_carries a disc G holding the
contact bar B in place and having a ward or flange H (or its equivalent two pins)
placed eccentrically upon its lower surface, forming a sort of crank pin or lever,
which when standing in a direction approximately parallel to the direction of the
bar, stands clear of the same; this ward is of such width and is so placed upon
the disc that it can be rotated about 30 degrees of the circle without touching the

page_text: bar B. When however the handle A is turned, the disc G revolves with it, one end
of the projecting flange H comes against the contact bar B and pushes it out from
between the jaws ee of the contacts E E. As soon as the bar is thus released, the
spring C draws it back until it is checked by the stops D D. Thus however slowly
the handle be turned, the contact bar is rapidly propelled away the instant the
contact is broken. When it is desired to again make contact, the handle is turned
the opposite way, the opposite end of the flange H comes in contact with the
connecting bar B, and forces it forward and between the jaws of the contacts E E
against the force of its spring C.
Referring to Figs. 3 and 4 the apparatus herein shewn works as above described,
in these A is the handle carried on a centre pivot a, B the contact piece. C. springs
controlling the contact piece B. E. friction contact catches. e jaws of contact
pieces. Ğ disc forming part of handle A. and carrying the ward or flange H which
operates the contact_piece B. A similar arrangement can be applied to various
kinds of switches. In place of the frictional device a catch could be substituted
and a tappet placed on the flange or pins to lift tho bar out of contact with the
catch, or vice versa, but I prefer frictional contact as shown.
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 improved switch or circuit closer as a whole substantially as described
and as illustrated in the accompanying drawings.
2nd. The combination of a pivoted bar held in contact by contact catches against
the force of a spring, with an actuating mechanism capable of forcing the bar into
the contact catches, and also, of liberating it from those catches in such manner as
to leave the spring free to exert its entire power on the bar alone clear of the
liberating mechanism, by which means the contact is suddenly broken and no time
left for a destructive arc to form substantially as and for the purposes described.
3rd. The actuating mechanism consisting of a handle or key with ward or two
projections so arranged as to push the contact bar before it, both when bringing
tlie contact bar into contact, and also when bringing it out of contact, thus leaving
the contact bar free from the actuating mechanism to dart away from the ward in
a forward direction in obedience to a superior propelling force, substantially as and
for the purposes described.
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