Improvements in Switches for Making and Breaking Electrical Circuits.
Year: 1888

page_text: COMPLETE SPECIFICATION.
Improvements in Switches for Making and Breaking Electrical
Circuits.
We, SIGMUND BERGMANN of the City, County, and State of New York, Manu-
facturer, and John Thomas DempsTER of the Town of Summit, in the County of
Union, and State of New Jersey, Electrician, both in the United States of America,
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 :-
Our invention relates to switches designed principally for making and breaking
such electric circuits as employ heavy currents, such as electric lighting circuits; and
to that character of switches, in which, in order to make and break the circuit with
rapidity and certainty and thereby prevent the formation of an arc at the contacts, a
spring movement is provided, so connected with the moving contact piece and with
an operating handle that the turning of the handle does not directly move the contact
piece, but acts to store up power in the spring, which is released by the continued
movement of the handle and throws the contact piece independent of the handle and
with a rapid and certain movement.
We do not claim the switch of this general character as of our invention, since we
believe this to be the invention of another..
Our invention however as stated, relates to such switches our object being to
produce such switches in a more simple, compact, durable and efficient form than they
have hitherto been made.
To this end, our invention consists in a peculiar construction and arrangement of
mechanism employed for producing the quick independent throw of the contact piece,
and in other details of construction of the parts of the switch which are hereinafter
fully pointed out and explained.
Our invention is illustrated in the accompanying drawings.
Figure 1 is a top view of a double pole switch embodying our invention with the
cover removed and with the parts under the base shown in dotted lines.
Figure 2a hattam viam of the same switch

page_text: Figure 5 a vertical section of the same switch, and
Figure 4 a view of the contacts and moving contact piece of a single pole
switch.
A is the base of suitable insulating material, one that is incombustible being
preferred. This base is preferably circular in form and is hollowed out on its under-
side to enclose the parts of the movement. B is the operating handle mounted
upon a spindle C, which passes centrally through the top of the base and is
perpendicular thereto. A metal bushing a surrounds the spindle where it passes
through the base, and forms a bearing for the easy working of the spindle. On
the end of the spindle beneath the top of the hase is secured a cam D, which is
formed of a plate and is constructed with an eccentric rise, from a point to an
opposite point c, and from point c the cam is concentric with the spindle to the
point d where there is a direct radial drop in the cam connecting the high point d
of the cam with the lowest point b. Two arms E, F, are pivotted by the screw e
to the underside of the base, near its edge and project towards the cam D, and
pins f, g, on the inner ends of the arms rest normally against the cam at the
opposite points b, c. These pins f, g, are connected by a spiral spring G which is
strained slightly and holds the pins normally against the cam.
Above the base, there is mounted upon the bushing a so as to turn freely thereon a
cross bar H. This bar has a pin h projecting from it downwardly into a curved slot i
in the top of the base. The arms E. F have fingers which project upwardly into
the slot i on opposite sides of the pin h, and normally embrace the pin. The cross
bar H is the moving contact piece of the switch or carries the moving contact
pieces as will be presently explained. The function of the parts that have been
described is to throw this cross bar first in one direction and then in the other.
g
The
With the parts in the position shown in Figure 2, the pin fof arm E rests at the
point c of the cam D at the top of the rise on the cam while the pin g of arm F' rests
at the lowest point b of the cam. Now the handle and cam being turned the inner
end of the arm F will be forced outwardly by the rise of the cam while the arm E
will remain stationary, its pin working on the concentric portion of the cam.
effect of this movement is to put the spring G under tension by spreading the
pins, 9 apart at the same time the finger k on the arm will move away from
the pin on the cross bar H. The movement being continued, the finger on arm F
will reach the end of the slot i, at the same time the point d of the cam will pass
under the pin on the arin E. The spring G being at its greatest tension, will draw
the pin fand the inner end of the arm E inwardly with great rapidity bringing the
pin to the lowest point 5 of the cam. The finger k on the arm E bearing on the
pin of the cross bar H, such cross bar will be thrown with rapidity under the full
power of the, spring G in one direction. Now if the handle is turned further, the
arm F will remain stationary while the arm E will be moved by the rise of the cam
again straining the spring and when the pin g of the arm F is passed by the point d
of the cam, the cross bar H will be thrown in the opposite direction with the same
rapidity and force.
m¹
For the contacts of a double pole switch, four posts I, I' and K, K¹, are mounted
on the base at opposite sides. From these posts, spring contact plates L, l' and m,
project around the edge of the base in opposite directions. The plates 1, l' are parallel
at their free ends and are placed one above the other, and this is also true of the
plates m,
m. The posts I, I', K; K', pass through the top of the base. They are
hollow so that circuit wires can be run up into them from the underside of the base,
and they have screws n above the base for securing the circuit wires.
One side of the circuit will be broken at the posts I, I' and the other side at the
posts K, K¹ so that by simultaneously bridging the springs 1, l' and m, m³, the two
sides or poles of the circuit will be closed.
To do this without forming a cross or short circuit, the cross bar H is perforated at
each end, and has two buttons o, o', of insulating material which are placed on
opposite sides of the bar and meet in the perforation. Two discs or plates p, p, of
copper are placed on the buttons o' and are connected by a copper rivet q which passes
0,

page_text: through the buttons. The buttons insulate the plates p, p' as well as the rivet q from
the cross bar. The cross bar has a similar set of connected contact plates at the
other end.
.
m,
When the handle is turned to throw the ends of the cross bar between the pairs of
stationary contact plates 1, 1, m', they will be bridged by the plates p, p¹ and
rivets q on the ends of the cross bar and the circuit will be closed. When the cross
bar is thrown in the opposite direction, it will leave the plates 1, and m, m² and will
break the circuit.
For a single pole switch (figure 4) only two posts I, L¹ will be used. These will
be on opposite sides of the base and the cross bar H will make metallic contact with
springs from these posts. The circuit when completed will pass from one post to the
other through the cross bar.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what we
claim is ;-
1. In an electrical switch the combination of the handle, the peculiar cam turned
by the handle, the pivotted spring-connected arms bearing on the cam, and the
moving contact piece, such parts being arranged and connected so as to operate
substantially as hereinbefore described.
2. In an electrical switch, the combination with the base, and the moving contact
piece, of stationary contact springs, posts from which such springs project, which
posts extend through the base, and are made hollow to admit the passing of circuit
wires from beneath the base up through said posts axially, and set screws in said
posts above the base to bind the circuit wires, substantially as hereinbefore described.
Dated this 24th day of January 1888.
SIGMUND. BERGMANN.
JOHN THOMAS DEMPSTER.
By Harris & Mills,
23, Southampton Buildings,
Agents.