Improvements in Electrical Tumbler Bwitches.
Year: 1897

page_text: Improvements in Electrical Tumbler Bwitches.
I, ALFRED WATSON, of Hockley Street, in the City of Birmingham, Electrical
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to detail improvements in tumbler switches for switching
on and off electrical currents for various purposes, and consists principally in fixing
the insulation or insulating material upon the back of the contact closer; also in
improvements in the construction and arrangement of the switch to obviate any
liability to short circuiting; and also in forming a sinking, or well in the base of
the switch for receiving the terminals and contacts of the switch, which thus
come below the level of the top edge of the said base, which is enclosed by the
usual cover.
In carrying out my invention, the tumbler lever, which may consist of an
inclined upper arm and a toe directed at an obtuse angle thereto and having a
ball joint at the middle part which may turn upon a crossing pin carried by the
seating of an elevated bracket wherein the said hall works so that when the said
tumbler is turned in one direction for making contact, its toe comes nearly into
a vertical position and impinges against the turned-up front stop of a heel piece
carried проп the top
of an insulating block of some non-electrical conductor such
as pressed fibre, ohina or the like, mounted upon the upper side of the hinged
contact closer, but when pushed or turned in the other direction, it impinges
against an erect front stop formed by the bending of the metal of the back end of
the heel piece, which with its back and front stops, is made from a strip of metal
having a single branch and two side ears at one end and two branches at the other
end the branches of both ends being embedded into the insulation material and
then clonched for affixing, whilst the ears are turned upwards to form the back
slop, the front stop being made, as described, by folding together the metal at the
shanks of the two end branches.
The contact closer consists of a lever, preferably made from sheet metal, and
having turned-down bracket ears at one end to form the bearing of the joint,
whilst the contact end is cranked downwards and has turned up wings at its sides,
which come against slightly yielding and opposed contact plates of the terminala
which have lead-binding screws as usual, and are fitted to the bottom of a central
well or sinking of the base. The said contact plates are formed by turning the
ends of the metal of the terminals upon themselves, so that they thus slightly yield
on the wings of the contact maker being forced between them.
The metal at the opposite edges of the body part of the contact closer is turned
up into dovetail or equivalent overhanging sides, whilst parts of the metal of the
body are pierced and turned upwards into ears or lips, one of which, before the
introduction of the insulation lies down flat, and then after the said insulation
has been slid into position between the overhanging edges of the contact closer
(between the top of which and the underside of the insulation a piece of tale may

page_text: be interposed) the said ear is then turned up and completes the boxing in of the
base of the insulation. The axis of the closer passes through the bearing ears of
the joint and also through the metal of the tumbler supporting bracket, and may
have threaded upon it, a coiled spring whose terminal ends constitute arms, one
pressing upon the bottom of the well of the base, and the other upon the under-
side of the contact closer, so that when the tumbler lever is turned from left to
right, or from one side to the other, the contact maker is automatically lifted out
of contact by the spring, which is compressed when the closer is turned in the
other direction for making contact by the toe of the tumbler lever wiping along the
plain part of the heel piece.
The whole of the terminals and contacts, and the contact closer lie within the
sunken middle or well of the base, thus practically enclosing or boxing in the
elements of the switch, as the only part coming above the said well is the tumbler
lever.
I wish it to be understood that I do not confine myself to the dovetail arrange-
ment for securing the insulation to the contact closer, as it may be secured thereto
by overhanging edges or equivalent means.
As a modification of the tumbler-insulating part of the invention, the middle
part of the closer is partially wrapped or covered with a strip of insulating fibre.
Becured thereto by a brass or other metal clin, a part of which is longitudinal slotted
and through which the toe of the tumbler lever takes and bears upon an exposed
strip of steel located between the clip and the fibre, to form a bearing or running
piece for the said tumbler toe to work along. The ends of the opening er guiding
slot on the surface of the fibre binding clip are turned up into ears, one of which
forms the stop and the other the heel piece. If required, the steel bearing plate
may be dispensed with.
Improvements in Electrical E
I, ALFRED WATSON, of Hockley Street, in the City of Birmingham, 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:-
This invention relates to detail improvements in tumbler switches for switching
on and off electrical currents for various purposes, and consists principally in pro-
viding the back of the contact closer with a block or strip of insulating material,
intervening between it and the acting end of the tumbler or operating lever, also
in improvements in the construction and arrangement of the switch whereby any
liability to short circuiting is obviated; and also in forming a sinking or well in
the base of the switch for receiving the terminals and contacts of the switch,
which thus come below the level of the top edge of the said base, the whole being
enclosed by the usual cover.
Figure 1 of the accompanying drawings represents a topside plan of a tumbler
switch (with the cover removed) constructed, arranged and provided with means
for insulating the tumbler lever from the contact closer arm and for preventing

page_text: Bhort circuiting between (Lfferent parts of the switch in accordance with one form
of my invention.
Figure 2 shows a cross section of the said switch (but including the cover) upon
the dotted liner, Figure 1. These said views Figures 1 and 2 represent the con-
tact closer in its "closed" position for making or completing the circuit.
Figure 3 is a like plan view of the switch as in Figure 1, but showing the closer
open for breaking the circuit.
Figure 4 is a cross section of Figure 3 upon the dotted line ³.
Figure 5 is a side elevation of Figure 1.
Figure 6 is a cross section of Figure 1 upon the dotted line, showing more
clearly the arrangement of the spring contacting parts of the circuit closing arm
and the contact plates or terminals of the circuit lead wires.
Figures 7, 8 and 9 respectively represent a longitudinal vertical section, a top-
side plan and a side elevation of the metallic part of the contact closer arm, the
insulating block upon its upper side being removed. The section Figure 7 also
shows the sleeve of insulating material which surrounds the joint pin of the said
arm.
Figure 10 is a partial cross section of Figure 1 upon the dotted line r', showing
more clearly the means employed for insulating the contact arm from its joint pin.
Figures 11, 12 and 13 represent a longitudinal vertical section, a side elevation
and a topside plan of the insulating block of the contact arm, also representing
the wearing or running plate on its topside upon which the acting end of the
tumbler lever runs and the heel and front stop against which the said end of the
tumbler lever impinges as hereinafter described.
Figure 14 is a cross section of Figure 11 upon the dotted line ☞³, looking towards
the heel.
The same letters of reference indicate corresponding parts in the said Figures 1
to 14 of the drawings.
In this arrangement of switch, a is the tumbler lever, consisting of an inclined
upper arm or operating end a¹, and an acting end or toe a², and having a ball
joint such as a, at the middle part which may turn upon a crossing pin b', carried
by the seating 6, of an elevated bracket b, wherein the said ball works so that when
the operating end of the said tumbler is turned in the direction
indicated by the full arrow in Figure 2 for making contact, the
toe a, comes nearly into a vertical position (see Figure 2) and impinges against
a front stop e, carried upon the top of an insulating block d, of some non-electrical
conductor, such as pressed fibre, china or the like, mounted upon the upper side e¹,
of the hinged contact closer e, but when the said lever is pushed or turned in the
other direction it impinges against an erect rear stop or heel f, also carried by the
eaid insulating block d, which thus intervenes between the tumbler lever and the
rocking contact arm and effectually insulates the one from the other.
The contact closer , consists of an arm, preferably made from sheet metal as
represented in Figures 7, 8 and 9, and having a pair of turned-down bracket ears e10,
at one end to form the bearing for the joint pin g', which is directed between the
legs b, of the elevated bracket b, whilst the contact end is preferably cranked
downwards at , and has turned up wings, at its sides, which come against
slightly yielding and opposed contact plates h', of the terminals h, which have lead-
binding screws h, as usual, and are fitted to the bottom of a central well or sink-
ing, of the base . The said contact plates formed by turning the ends of the
metal of the terminals upon themselves, so that they thus slightly yield on the
wings of the contact maker being forced between them.
The metal at the opposite edges of the body part of the contact closer is turned
un into dovetail or equivalent overhanging sides et. whilst parts e³, 6, of the metal
of the body are cut out and turned upwards into ears or lips, one of which, before
the introduction of the insulation d, lies down flat, and then after the said insula-
tion has been slid into position between the overhanging edges or dovetail sides et.
which preferably take into to corresponding grooves, in the sides of the said

page_text: block, the said ear is then turned up and completes the boxing in of the base of
the insulation between the back and front ears es, e, and the sides e'. The axis
of the closer, which, as aforesaid, passes through the bearing ears of the joint and
also through the sides of the tumbler supporting bracket, has threaded upon it,
a coiled spring j, whose free ends are formed into arms j', , the former of which 6
presses upon the bottom of the well of the base, whilst the latter bears upon the
underside of the contact closer, so that when the tumbler lever is turned in the
direction indicated by the dotted arrow in Figure 2, the contact maker is auto-
matically lifted out of contact and given a fly action by the spring, which is com-
pressed when the closer is turned in the other direction for making contact by the
toe of the tumbler lever wiping along the plain part of the heel piece.
The whole of the terminals and contacts, and the contact closer lie within the
sunken middle or well of the base, thus practically enclosing or boxing in the
elements of the switch, as the only part coming above the said well is the tumbler
lever.
The axis or joint pin g', of the contact arm is preferably surrounded nearly
throughout its length by a sleeve 9, of insulating material and washers 9, of
similar substance are fitted onto the ends of the said sleeve, so that the contact arm
is thereby completely insulated from the joint pin and the sides of the elevated
seating of the tumbler lever. The top side of the insulator block d, may be pro-
vided with a wearing strip of steel or other metal k, along which the acting end of
the tumbler lever runs to and fro, whilst to prevent current passing from the
tumbler lever to the embedded parts of the stops c, and f, a strip A, of mica, tale
or the like is interposed between the topside of the contact arm and the base of
the insulating block d.
Instead of making the back and front stops and f, in the form of separate
studs embedded into the material of the insulating block, the said stops together
with the wearing strip may be formed integrally from a single piece of metal.
Figure 15 represents a section of a tumbler switch so fitted. The front stop c, is
nade from an ear formed from a part of a sheet metal blank, of which the middle
part c', forins the wear or running plate, whilst the rear stop f, is formed from the
other end of the said blank and from it the metal is continued downwards and
into an attachment ear f, and is embedded within the fibre or other non-conduct-
ing material of the block d. The other attachment piece c³, is cut out of the
middle of the blank passed through the block and preferably clenched on the
underside.
As a modified method of insulating the contact arm, the insulating material may
be in the form of a length or strip of suitable dimensions, which is wrapped around
the body part of the said arm and is secured there by a clip or like device.
Figure 16 is a perspective view showing the contact arm with the length or strip
of insulating material being applied or wrapped around the same.
Figure 17 is a plan and Figure 18 a section of the clip applied for securing
the insulating wrapping to the contact arm.
Figure 19 represents a plan and a section of the running strip which is placed
upon the top of the insulation and below the longitudinal slot in the clip.
Figure 20 is a cross section of the insulated contact arm completed.
Thus, in the said Figure 16, el is the middle part of the closer which is partially
wrapped or covered with a strip of insulating fibre d, secured in position by a brass
or other metal clip m, the arms m', of which are folded round the material d,
whilst the middle part is longitudinally slotted at m³, and through which the lor of
the tumbler lever takes and bears upon an exposed strip of steel located between
the clip and the fibre, and forming a bearing or running piece for the said tumbler
toe to work along. The metal at the ends of the opening or guiding slot in the
surface of the fibre binding clip is turned up into ears e, f, one of which forms the
stop and the other the heel piece. If required, the steel bearing plate may be
dispensed with.

page_text: Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
First In tumbler switches provided with a block or strip of insulating
material intervening between the contact arm and the acting end of the tumbler
lever-affixing the said insulating material to the contact arm by means of cars
and turned up dovetail or equivalent edges, integrally formed out of the metal of
the contact arm, substantially as herein described and set forth.
Secondlyn tumbler switches provided with a strip of insulating material
intervening between the contact arm and the acting end of the tumbler lever, the
employment of end stops against which the said tumbler comes with or without a
strip of mica or tale located between the insulation and the said arm, substantially
as and for the purpose herein described and set forth.
Thirdly-The modified method of insulating the contact arm of a tumbler
switch from the tumbler lever, consisting in wrapping the said arm in a length
of insulating material secured in position by a clip or equivalent fitting, with or
without a wearing or running strip, substantially as described and set forth in
Figures 16 to 20.
Dated tms nauy
1030
ALFRED WATSON,
By Henry Skerrett,
24, Temple Row, Birmingham, Agent for Applicant.