Improvements in Electric Switches.
Year: 1892

page_text: Date of Application, 4th June, 1892
Complete Specification Left, 6th Mar., 1893-Accepted, 13th May, 1893
PROVISIONAL SPECIFICATION.
Improvements in Electric Switches.
I CARL THOMAS BLANCH BRAIN of 34, South John Street, Liverpool,
Electrical Engineer do hereby declare the nature of this invention to be as
follows:-
An improved method of constructing and fixing an electric switch, whereby it is
made stronger and simpler and the number of holes necessary to drill into the base
plate, less..
This
The connecting bar of the switch, which may be of the ordinary double break
swing bar pattern,-turns loosely on a pin, which is firmly fixed in the base-plate.
This pin has a turned head on the facing or upper end, instead of the usual nut and
washer, which holds the bar down. The pin has also a shoulder turned upon it, so
that it can be pushed into the base-plate on the face or upper side, up to the
shoulder and fastened with a nut and washer at the back. Into this pin on
each side is cut a square slot, from under the head to the end of the pin. In
this slot is laid a square steel spring bending round the end of the pin and lying
in the slots on each side. The ends of the spring exert a strong outward pressure
against the sides of the hole in the connecting bar, in which the pin is.
central hole in the connecting bar, is recessed out slightly, to allow the ends
of the spring to expand outwards. The recesses being set at such an angle as to
cause the springs as they expand into them to force the connecting bar to swing
round to a certain position. The square steel being held firmly in the pin slots,
and the ends being then let into the bar a short distance, it cannot be moved further
round than the recesses allow. By this arrangement, the pin, spring and connecting
bar are self contained. The spring only acting over a fixed angle, and being it's
own stop.
These are fitted together and the pin is set in the base, so that the
spring just comes into action as the connecting bar is leaving the terminals, causing
the break to be sharp and also stopping the bar after it has turned far enough off.
Therefore, one central hole in the base-plate, suffices for fixing everything
except the terminals. The connecting bar is fitted to turn easily on the pin, it has
a slight rock, and room to move a little up and down, so as to find it's way easily
into, and make a good contact with, the terminals.
Where it is required, to have a detached handle, I make it like a spanner.
It
may fit into or against projectious on the connecting bar; or have it's ends shaped
to fit into slots cut in the bar. In either case it is fitted with a certain amount of
play or freedom, so that the switch can always automatically make a quick break,
independent of the handle. When the handle is attached, the piu is made a little
longer, so that the handle may be fitted to turn loosely on the pin just above the
connecting bar. The head of the pin coming on top of that part of the handle.
The handle being inade to operate the bar, similarly as before described.
Dated this Third day of June 1892.
C. T. B. BRAIN..
COMPLETE SPECIFICATION.
Improvements in Electric Switches.
I CARL THOMAS BLANCH BRAIN of 34 South John Street, Liverpool
Electrical Engineer do hereby declare the nature of this invention and in what
5 manner the same is to be performed, to be particularly described and ascertained'
in and by the following stateinent :-
An improved method of constructing and fixing an electric switch; whereby it is

page_text: The invention relates to those switches which have a connecting arm or bar,.
moving upon a pin or pivot, and having a spring or other means attached whereby
a quick break is obtained; and the improvements consist in the construction and
arrangement of the spring and the pin or pivot, the method of fixing the same; and
in the manner in which the said spring is caused to operate the movable connecting
bar.
In the accompanying drawings;-
Fig. 1. is a plan of a switch with my improvements, the handle not being shown.
Fig. 2. is a side elevation of the center pin and spring, shewing part of the
movable bar in section.
Fig. 3. plan of washer shewing details hereafter referred to.
Figs. 4 & 5, are a plan and side elevation of the handle.
In Figs. 1. and 2, a, is the center pin, b, the spring, c the movable bar, d, the fixed
washer, and g, the insulating base.
The center pin a, is fixed firmly in the base; it has a shoulder turned upon it.
against which the washer d is fitted, the pin being then pushed into the base and
tightly. fixed by the nut and washer at the back, as shown in Fig. 2. On each side
of the pin a lug projects, which is fitted into a suitable slot in the base. The lugs
also extend up the pin, as shewn at f Fig. 2. and pass into slots in the washer d.
Fig. 3. shews a plan of the washer, on the base, and the slots marked f', f¹, are
those through which these lugs pass, thus keying the washer and pin firmly to the
hase and to each other, it being impossible to turn either round in the hole. On
each side of the pin but at right angles to the lugs, a small slot or groove is cut,
parallel to the axis, as shewn dotted in Fig. 2. The slots are of even depth, and
run the length of the pin, cutting through the head or flange. At the lower end of
the pin, the slots are cut into one, the pin being cut right through, and fitted to-
receive the Ụ shaped spring b. b. This spring sinks into the groove at the bottom
end of the pin, and is held in position by the nut and washer.
The ends of the spring pass into the slots in the flange or head of the pin, and
just reach to the upper surface as shewn in Fig. 2. Thus, when in position the
spring is closely confined to the grooves of the pin.
The connecting movable bar, c, is bored to turn loosely on the pin. When the
switch is turned "on," the bar being in the position shewn in Fig. 1., the Ū spring
is compressed, and sinks into the grooves as at b, b, allowing the bar to be turned,
with a certain amount of friction; the grooves being of such depth that at this.
portion of the pin the spring can be compressed within the diameter of the pin
as shewn.
It will be evident that the spring in such position exerts a strong outward
pressure against the sides of the hole in the bar, c. Now this, central hole in the
movable bar is recessed slightly out as shewn by the dotted lines in Fig. 1. Two
small angular recesses, being cut into the bar, diametrically opposite. The recesses
are placed at such an angle, relatively to the position of the spring and the center
line of the bar, that as the switch is being turned to the "off" position, just before
the bar leaves the terminals, the spring commences to expand into the recesses, and
thereby suddenly forces the bar off, until the spring reaches the bottom of the
recesses. The centre line of the bar being then in the position shewn by the
line, s. s.
As the spring is still somewhat compressed the bar is firmly held "off,"
but is unable to turn any further, as the spring is against the shoulder of the
recess, the spring itself being held by the slot in the bottom of the pin, and its
ends by the slots in the head or flange, it's position being shewn in Fig. 2. which is
an elevation, of the switch when turned "off." Both the base and washer, d, are
slotted to clear the spring and allow it a free movement. Fig. 2 is a section of
base, g, through these slots, which are shown at el, e', on Fig. 3. The recesses in
bar, c, being marked e, e, on Figs. 1 and 2. By this arrangement, the spring, centre
pin and connecting bar are self contained and one hole in the base suffices for fixing
them all.
:
The bar is perfectly free to make a good contact, it being allowed an amount of

page_text: play as shewn Fig. 2. so that it may move, or rock a little on the pin a. and thus.
find an even seat or contact in the terminals.
The action of the spring is centrifugal and balanced, and so applied to the bar
that it does not hold the latter rigid or cant it on either side, which would prevent
the bar making a good easy contact. In Fig. 4. is shewn the handle which in this.
instance is like a claw or box spanner, fitting over the bar, c. The handle is pivoted
upon the centre pin, a centre hole being drilled at n, through which the pin passes..
The handle being hollowed out to receive the bar, slides down on to the upper
face of the flange or head of the pin, and when attached to the switch can be
held by a washer fitted to the shoulder and screwed down by a nut on the top,.
threaded end of the pin shewn in Fig. 2. The handle is recessed out so as to
clear the centre boss of the bar c. and is of course held off it by the flange or
centre pin head. The position shewn in Fig. 4. is exactly that in which the
handle would be if placed on Fig. 1. and the dotted lines shew the shape of the
claws on each side of the bar, Fig. 5. being the side view.
" on
"
In Fig. 4. it will be noticed the spaces for the bar between h and m on each
side of the end of handle are much wider than the bar, c. This allows the
bar to make a free quick break. In turning the switch from the position
shewn in Figs. 1 and 4. to the "off" position indicated by the
line s. s, the shoulders of the claws at h, h, are brought in contact with the adjacent
edges of the bar, forcing it round. When, however the spring comes into action,
the bar which is free to move independently of the handle is forced quickly round
to the position s. s. it's opposite edges at the same time striking the respective
shoulders of the claws at m. m. The insulated portion of the handle is shewn at p.
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. In an electric switch, the combination of a fixed pin or pivot having a groove
or grooves, an expanding spring fitted in the same, and a loose bar or connecting
arm turning on said pin with an angular recess or recesses in which the spring
expanding operates the bar, substantially for the purpose and in the manner herein
described.
2. In an electric switch, the lugs in Fig. 2. keying the centre pin, washer and
base together, substantially as described.
3. In an electric switch, the construction and arrangement of centre pin, washer,
and movable bar, substantially as herein described and illustrated in Figs. 1, 2,
and 3.
Dated this 3rd day of March 1893
•
C. T. B. BRAIN.