Improvements in Switches for Electric Circuits.
Year: 1898

page_text: Improvements in Switches for Electric Circuits.
I, GILBERT WRIGHT, of Wilkinsburg, County of Allegheny, and State of Pennsyl-
vania, United States of America, Engineer, do hereby declare the nature of this
invention to be as follows:-
:―
This invention relates to electric switches and has for its object to construct an
improved switch of the kind or class known as "double-throw" switches in which
one movement of the operating handle breaks the connection between one pair or
set of contacts, and immediately after makes the connection between another pair
or set of electric contacts.
The invention is primarily intended for connecting either of two dynamos in
circuit with a single pair or set of feeders, or for connecting a single dynamo
with either of two pairs or sets of feeders, but its use is not limited to this particular
purpose.
The improved switch is constructed with sliding contacts preferably of the plug
and socket type, in which when the plug is home in its socket the circuit is closed
and when it is out of the socket the circuit is broken.
According to this invention two such switches or two pairs of such switches are
placed side by side with a lever pivoted between them, said lever is provided with
a pair of cams adapted to engage with the movable contacts of the switches in such
a manner that when the lever is turned on its pivot in one direction the circuit
through one of the switches is broken and the circuit through the other of the
switches is made; while if the lever is turned in the other direction the operation
is reversed.
The switches may be either of the single pole or of the double pole type, or a
number of switches may have their movable contacts connected together so that
they are operated simultaneously.
When switches of the plug and socket type are employed, a blow-out opening
is preferably provided in the side of the socket, so that any are formed at the

page_text: moment of breaking the circuit expands the air in the socket and causes a blast
through the opening which blows out said arc.
W. P. THOMPSON & Co.,
322; High Holborn, London, W.C.,
Patent Agents for the Applicant.
1
improvements in WITCHES FO
I, GILBERT WRIGHT, of Wilkinsburg, County of Allegheny, and State of Pennsyl-
vania, United States of America, 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 invention relates to electric switches.
"
One object of the invention is to construct an improved switch of the kind or, class
known as double-throw" switches in which one movement of the operating handle
breaks the connection between one pair or set of contacts and immediately after
makes the connection between another pair or set of contacts.
Another object of the invention is to provide for extinguishing the arc formed on
separating the switch contacts. For this purpose I arrange that the contacts
shall be enclosed in a chamber made of incombustible material, said chamber
having an orifice at or near the place where the arc is formed, so that the air heated
by said arc upon expanding rushes out through the orifice, causing a blast which
blows out the arc.
In order that my invention may be clearly understood, I will proceed to describe
the same with reference to the accompanying drawings, in which
Figure 1 is a plan, and
Figure 2 a side elevation partly in section of a double-throw switch, con-
structed in accordance with my invention, the terminals and movable contacts
being of the socket and plunger type.
1s the base, a switch board panel for example, which supports a casting 6 to
which are secured incombustible insulating tubes 2. Said tubes are provided at
each end with switch terminals 3 having binding clamps 4 to which the circuit
wires are connected. The casting 6 serves as a guide for the rod 9 which is secured
to a cross-head 8 carrying the plungers 7 forming the movable connections between
the contact terminal 3. These plungers slide in and out of the tubes 2 and when
in the contacts 3 will be connected, and when out, as shewn in Figure 2, the said
contacts will be disconnected. The apparatus shewn in the drawing comprises
two double pole switches, but obviously single pole switches may be used with a
similar apparatus. The operating mechanism consists of the lever 13 provided with
a handle 14 and pivotally supported in a bracket 12 secured to the base 1. The
lever 13 has a head 15 provided with two cam-shaped jaws 16 as clearly shewn in
Figure 1. These jaws engage with rollers 11 provided at the ends of the operating
rods 9 of the switches. In the position shewn in Figure 1, the uppermost pair of
switches are closed and the lower opened. If the lever 13 be rotated on its pivot
in the direction of the arrow the operating rod 9 of the upper switches will be
pressed in so as to open the circuit through those switches, and immediately after
the other pair of jaws 16 will engage with the roller 11 of the operating rod of the
lower pair of switches pulling that out and closing the circuits through said
switches, hence one movement of the handle breaks one circuit and closes the
other circuit.

page_text: The tubes 2 are provided with openings 5 through which the air within the
chamber when expanded by the heat due to the are formed on breaking the circuit
rushes out and causes a blast which blows out the arc.
The improved apparatus is not limited in respect of the number of circuits which
can be opened and closed by one handle, and it is clear that a considerable number
of switches might be arranged with their plungers connected to a common operating
rod which is adapted to be moved by the cams on the ends of the arms of the switch
lever.
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. A switch for breaking the connection between one pair or set of electric
contacts and immediately after making the connection between another pair or set of
contacts, in which the operating lever has arms provided with cams, which cams
as the lever is rotated on its pivot are adapted to engage alternately with the
movable portions forming the connections between the respective pairs or sets of
contacts, substantially as described.
2. A switch in which the terminals of the circuit are connected to fixed contacts
at the ends of an incombustible insulating tube, the movable contact of the switch
being formed of a plunger sliding between the fixed contacts, and the interior of
the tube communicating with the outside through an orifice, through which the air
within rushes out when heated by the arc formed on breaking the circuit, for the
purpose specified.
3. Switches constructed and operated substantially as describéd with reference
to the accompanying drawings.
Dated the 4th day of January 1899.
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C.,
Patent Agents for the Applicant.