Improvements in Electric Switches.
Year: 1891

page_text: Date of Application, 16th Oct., 1891-Accepted, 5th Dec., 1891
COMPLETE
SPECIFICATION.
Improvements in Electric Switches.
I, OLOF LINDERS, of Gothenburg, in the Kingdom of Sweden, 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 :-
This invention relates to a simple form of reversing switch for use where it is
required to change the direction or polarity of an electric current.
The advantage of the improved switch over those heretofore used, consists
principally in the fact that the sparking at the contacts, which have heretofore
been so destructive to the contact pieces, is prevented. This is effected by
combining with the reversing switch a circuit breaker by which the said switch is
manipulated, the said circuit breaker being so connected to the switch, that on
actuating the said switch, the current is interrupted by the circuit breaker, before
contact has been made between the contact pieces of the switch; and it is evident
that, in order to prevent sparking at the circuit breaker this latter must be made
to act instantaneously by being provided with a so called snap motion.
In the accompanying drawing
Figure 1 is a view showing the parts in the position they occupy before the
direction of the current is changed.
Figure 2 shows the position of the parts when the current is interrupted; and
Figure 3 after the change of direction of current has taken place the circuits in
all cases being shewn diagrammatically.
9,
The current is led from the source of electricity through the circuits a and b to
the apparatus and by the circuits c and d from the apparatus to the place where it
is to be used. In the former the polarity is always constant, but is variable in the
latter. The fixed contact pieces of the commutator are arranged in two concentric
circles, the inner one consisting of the contact pieces e fand g and the outer one
of the contact pieces h, i and j. The movable contact pieces which are two in
number k and are pivotted at their centres m from which they are insulated. The
said movable contact pieces are insulated from each other and are of different
lengths, so that the ends of the piece k reach only to the contact pieces e and
while the other 1, reaches to the contact pieces hj. On the drawing the contact
piece is represented broken in order to show the movable contact piece k. An
arm or lever n is also pivoted to the centre m which arm engages with the three
contact pieces p q and r, which are also placed concentrically around the pivot m.
At one of the extreme positions of the arm or lever n shown in Figure 1 the circuit
is closed, as one of the contact pieces p or r, belonging to the circuit a is then
connected up with the contact piece q likewise belonging to the circuit a.
arm or lever n thus serves as a circuit breaker the contact pieces k and l being
turned simultaneously with it.
The
At the central position of the arm or lever n as shown in Figure 2 the switch
contacts are interrupted. The reversal of the current may be effected as shown in
Figure 3 by turning the contact pieces k and by means of the arm or lever n a
quarter of a revolution, whereby the same, in lieu of being in connection with the
circuits a and b respectively, are connected up with the circuits band a respectively
or vice versa. In this case however the current is always interrupted before contact
has taken place between the contact pieces in the switch so that the latter are
always actuated whilst free from the current, and the current remains interrupted
until the contacts in the switch have been closed. Preferably the arm or lever n
is so arranged that it is first raised, the current being thereby interrupted, and
then turned, and the raising of the arm may likewise serve to act upon some form

page_text: of rapid contact interrupter so as to avoid the sparking at the contacts. All the
contact pieces may be placed either in the same or in different planes, according to
circumstances.
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 I
claim is :-
In an electric switch, a.central pivot on which are fixed the contact pieces k and l
which, by being turned from one extreme position to the other, cause the current
to be reversed, and an arm or lever serving to turn the spindle and the said contact
pieces,. the aforesaid arm or lever serving to interrupt the current before the
contacts of the switch are opened, or by means of which the current remains broken
until the contacts of the switch have been connected up with..one another,
substantially as and for the purpose herein before described.
Dated, this 16th-day of October 1891.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant: