Improvements in Electric Switches.
Year: 1899

page_text: Date of Application, 6th Feb., 1899-Accepted, 11th Mar., 1899
COMPLETE SPECIFICATION.
Improvements in Electric Switches.
I, EDWARD LIONEL JOSEPH, of 109, Brondesbury Villas, Kilburn, London,
Electrical Engineer, do hereby declare the nature of this invention, and in what
manuer the same is to be performed, to be particularly described and ascertained
in and by the following statement:―
This invention relates to an electric switch the contact piece of which is
operated by a lever, and is held in the open position, and in some cases in the
closed position also, as may be required, by means of a spring, such spring also
completing the opening movement of the contact piece independently of the
operating handle as soon as the latter has moved the said contact piece a certain
distance, whereby the possibility of leaving the contact piece within sparking
distance of the conductor terminals is prevented.
And in order that the said invention may be fully understood I will now proceed
to describe the same with the aid of the accompanying sheet of drawings, in which
Figure 1 is a side elevation of a switch constructed in accordance with my inven-
tion, and Figure 2 a plan of same.
A is the base-plate or block to which the various parts of the switch are con-
nected. This base-plate or block is preferably made of non-conducting material,
but it may be made of conducting material, the various parts being in that case
properly insulated from it. B, Bare the conductor terminals, between which the
U-shaped contact-piece C is inserted when the electric circuit is to be closed.
D is a bracket or carriage fixed to the base-plate A, and to which is pivotted at E
an arm F carrying the contact-piece C. This arm F has a slot G formed through
it. A lever handle H passes through this slot and is pivotted at I to the bracket
or carriage D. The contact-piece C, which is preferably made of several lamina-
tions of sheet brass or other suitable metal, is secured in a recess or groove J.in
the end of the arm F by means of a screwed stud K and nut L, the latter press-
ing against a washer plate M so as to wedge it in between the two arms of the
contact piece C. By screwing or unscrewing the nut L more or less on the
stud K these arms can be adjusted so as to bear more or less firmly against the
terminals B, B when their ends are pressed in between the latter. The arm F
has a wedge-shaped prolongation N extending down below the pivot E. P is a
pin working in a hole in the base of the bracket or carriage D) and provided with
a head Q. Between the head Q and the base of the bracket or carriage D is
placed a coiled spring R the constant tendency of which is to press the head Q of
the pin P upwards against the prolongation N of the arm F.
In Figure of the drawings the contact-piece C is shown by full lines in posi-
tion between the terminals B B, so as to close the electric circuit, having been
brought into that position by the movement of the lever handle H in the direction
of the arrow S and its action on the front end of the slot G in the arm F. In this
position of the contact piece C and the arm F the end of the wedge-shaped pro-
longation of the latter has pressed the head Q of the pin P downwards compress-
ing the spring R, the upward pressure of which may assist in retaining the arm F
and contact-piece C in the closed position. When, however, the lever-handle H

page_text: is moved in the direction of the arrow T it first comes to bear against the rear
end of the slot G, and a continuance of the movement of the lever-handle turns
the arm F backwards on its pivot E so as to raise the ends of the contact-piece C
clear of the terminals B, B. By the time this has been accomplished the end
of the prolongation N of the arm F will have been moved forward on the head Q
of the pin P into a position in front of the pivot E, and the spring R then acts
upon the said end of the prolongation N and throws the arm F and contact-piece C
up into the position shown in dotted lines in Figure 1 so that the ends of the
latter are removed to such a distance from the terminals B, B that there is no
fear whatever of sparking. When the arm and contact-piece are in the position
shown in dotted lines they are held in that position by the inclined part of the
prolongation N being pressed against by the head Q of the pin P. The sudden
action of the spring R on the arm F would be liable to jerk the hand lever H
out of the hand of the operator if the slot G in the arm F were only just long
enough to allow sufficient play of the lever H to enable it to perform its function
of moving the arm F; but to obviate this the slot G is made sufficiently long to
enable the arm F to be moved into the extreme elevated position by the spring R
independently of the lever handle H, and without the front end of the slot coming
into contact with the lever H, which merely lies loosely against the back end of
the slot G when the arm F and contact-piece Care in the elevated or open position.
The bracket or carriage 1) and the arm F may be made of malleable iron or
other cheap material as they are not required to be good conductors of electricity.
Having now particularly described and ascertained the nature of the said in-
vention, and in what manner the same is to be performed, I declare that what I
claim is:-
First. An electric switch consisting of a pivotted arm carrying a contact-piece
adapted to make contact with the two conductor terminals, and acted upon by a
spring in such manner that the contact-piece is moved thereby into and held in
the open position at such a distance from the conductor terminals as will obviate
the possibility of sparking, and an actuating lever-handle operating in a slot in
the said pivotted arm, substantially as described with reference to the drawings.
Second. In an electric switch having a U-shaped contact-piece the ends of
which make contact in the closed position with the conductor terminals, the device
for adjusting the pressure of the ends of the contact-piece against the terminals
when in the closed position, which consists of a wedging washer plate between
the branches of the U-shaped contact-piece, operated substantially as described
with reference to the drawings.
Third. An electric switch constructed and operating substantially as described.
Dated this 6th day of February 1890
E. L. JOSEPH.
Per W. H. Beck,
115, Cannon Street, London, E.C., Agent.