An Improvement in Electric Switches.
Year: 1889

page_text: Date of Application, 7th Nov., 1889-Accepted. 14th Dec., 1889
COMPLETE SPECIFICATION.
An Improvement in Electric Switches.
I, WILLIAM WHITE of Langside, Baker Road, Harlesden in the County of
Middlesex, Electrical 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 :-
My invention relates to a simple and inexpensive construction of electric switch
so arranged that in one position it makes effective contact for closing the circuit to
which it is applied, and that, when it is moved a little from that position, it
automatically inakes a rapid and complete break of contact, as I shall describe
referring to the accompanying drawings.
Fig. 1 is a vertical section.
Fig. 2 is a plan, the cover and the handle above the line X in Fig. 1 being supposed
to be removed.
A is a strip of brass or other suitable metal the two ends of which are divided by
slits into three, or it may be more, parts which are stepped in their length so that
the first is a little longer than the second, the second than the third and so on.
These parts are bent down so that their ends are at the same level but at different
radial distances from the centre of the strip which is fitted on a central spindle M.
In order to strengthen the middle portion of the strip A through which the spindle
passes, a piece J is fixed on it by rivets solder or otherwise. On a base G of
insulating material are fixed two diametrically opposite contact plates F which are
radially stepped in correspondence with the steps of the bent ends of the divisions
of A, and have the edges of their steps sloped a little downwards. In the centre of
the base G is fixed a metal bush N through which passes the spindle M. In a recess
in the underside of the base G is a spring S bearing against the bolt head of the
spindle M so as to urge the spindle downwards. Above the piece J, the spindle M
passes through a hole in a metal washer K and in a handle head I of ebonite or
other suitable insulating material to which the washer K is fixed by screws. In a
recess at the top of the head L there is a nut screwed on the end of the spindle M.
A pin R fixed in the piece J stands up into a circularly slotted hole C made in the
washer K. Under the strip A there is a helical spring P the one end of which is
inserted into a hole in the bush N, and the other end into a hole in the strip A, the
spring being so set as to bring the strip A into the dotted position A' shewn in Fig. 2
in which position the circuit is open. The internal parts are covered by a hood H.
The two contact plates F being connected respectively to the wires of the circuit to
which the switch is applied, the operation is as follows:-
When it is desired to close the circuit the head L is turned by hand and the
pin R being at one end of the slot C, the strip A is caused to turn with it in
opposition to the spring P, until the bent ends of A simultaneously reach the steps
of the contact plates F. By a little more force applied to the head L, the bent
arms of A are caused to mount the slopes at the ends of the steps of F, the spring S
yielding a little to allow the moving parts to rise until the stepped ends are in close
contact with the plates F closing the circuit. The switch is held in this position by
the strain of the spring S pressing the bent ends of A down on the plates F.
When it is desired to open the circuit the head L is turned backwards until the
other end of the slot C reaches the pin R and begins to move the strip A along
with the head. After a little motion enough to release the bent ends of A from
their strain on the plates F, the spring P causes the strip A to make a rapid move
ment, and thus the bent ends of A are almost instantaneously removed from contact
with the plates F, and the circuit is opened.

page_text: Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what
claim is
1. An electric switch consisting of central spindle M on which are fitted an
insulating handle L having a circular slot C, and a metal strip A having its ends
stepped and divided and having a pin R engaged in a slot C, in combination with
springs S and P and with stepped contact plates F, the whole mounted on an
insulating base G, substantially as described.
2. In an electric switch, stepped contact plates in combination with correspondingly
stepped contact arms substantially as described.
Dated this 7th day of November 1889
ABEL & IMRAY,
Agents for the Applicant.