Improvements in Tumbler Switches for Electrical purposes.
Year: 1899

page_text: Date of Application, 11th Mar., 1899
Complete Specification Left, 31st May, 1899-Accepted, 8th July, 1899
PROVISIONAL SPECIFICATION.
Improvements in Tumbler Switches for Electrical purposes.
İ, ALFRED WATSON, trading as A. Watson and Company, 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 tumbler switches for electrical purposes, and has for one
of its objects, to provide in connection with such devices, a sliding shutter of
insulating material, adapted to be brought in between the terminals (on connection
being broken) for the purpose of obviating sparking between the poles as is apt to
occur with the high voltage currents now in common use, whilst another object is to
simplify the construction of the switch operating mechanism.
In carrying out one form of my invention, I take a base of insulating material,
such as china, with the pole terminals passing through the bottom of the same,
adapted to be bridged for making. circuit by a spring sided or other contact maker
mounted upon an arm which turns at the rear upon a pivot mounted in an upright
bracket, upon the summit of which is the seating or bearing of a ball centred tumbler
lever, with its end preferably cleft with a small roller running within the cleft and
wiping over the edge of a feather plate or rib, which is V-shaped or provided with
two meeting inclined surfaces forming arms or stops against one or other of which
the tumbler impinges for rocking the contact piece, and the parts are in their "make
positions the contact piece is locked between the terminals by the tumbler lever
coming behind the forward end stop.
The rear end of the contact piece arm is provided with a depending limb or spur
which engages in a hole formed within or made through a traversing insulator shutter
having a to and fro movement within a groove formed within the base of the switch
and in such a direction that it will cover up or come between the terminals when the
switch is in its break position, but will be automatically removed therefrom when
the switch is in the "make" position.
The said shutter, which is thus traversed by the rocking of the contact piece arm,
preferably has inclined edges coming underneath like inclined edges of the groove
whereby it is prevented from rising off the bed in which it moves.
A spring is arranged to come behind the sliding shutter and has the double
function of taking the said insulating slide between the terminals and imparting a
Hy or quick break action to the contact piece through the depending limb connected
with the said slide or shutter, whilst the wiper rib or comb plate is preferably
embedded in insulated material carried between the box-like sides of the arm of the
contact piece.
ሰለለ

page_text: Improvements in Tumbler Switches for Electrical purposes.
I, ALFRED WATSON, trading as A. Watson and Company, 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 tumbler switches for electrical purposes, and has for one of
its objects, to provide in connection with such devices, a sliding shutter of insulating
material, adapted to be brought (on the circuit being broken) between the poles or
terminals and the contact maker for the purpose of obviating arcing between the said
poles pieces and the contact maker as is apt to occur with the high voltage currents
now in common use, whilst another object is to simplify the construction of the switch
operating mechanism.
In order to prevent arcing in electrical switches for use with high voltage currents, it
has heretofore been proposed to insert a piece of insulating material between the
poles, such as in the case where a china or like projection forming a part of, or attached
to, the base is left between the terminals, but such an arrangement, especially in
damp or dusty situations, lends itself to conductivity and does not prevent the arc (on
the circuit being broken) following the contact maker. Such arcing I propose to
prevent by the employment of an insulating shutter, which, by the act of operating
the switch lever for breaking the circuit, thrust or brought over the terminals and
interposed between them and the contact maker.
Figure of the accompanying drawings represents a tumbler switch (with the
cover removed) provided with an arcing-prevention shutter and improved operating
mechanism in accordance with my invention. This view is shown partly in elevation
and partly in longitudinal vertical section upon the dotted line x Figure 2, which
shows the said switch in plan. In both these views, the parts are shown in their
break positions and with the shutter intervening between the terminals and the raised
contact maker.
Figure 3 represents another longitudinal section of the switch but with the parts
in their circuit-making positions with the contact making bridging the terminals and
the insulating shutter withdrawn. This section is taken upon the dotted line x¹
Figure 4, which latter represents a plan of Figure 3.
Figure 5 is a cross section of Figure 4 upon the dotted line x², showing the contact
made and the shutter withdrawn.
Figure 6 shows a cross section of Figure 2 upon the dotted line 3 showing the
contact broken and the shutter intervening between the poles and the contact maker.
Figure 7 represents a plan of the base of the switch and the insulating slide
shutter, the latter being shown in the position into which it is thrust on the contact
maker being lifted from between the terminals, whilst
Figure 8 shows a similar view as Figure 7 but with the shutter withdrawn.
Figure 9 represents a plan, an edge view and a longitudinal section of the insulat-
ing slide or shutter separately.
Figure 10 is a side elevation and Figure 11 a plan of the contact maker, which is
operated by the tumbler lever of the switch and in turn, imparts movement to the
shutter for withdrawing it from over the terminals, it being understood that the for-
ward movement of the said shutter is effected, when the contact maker is lifted for
breaking the circuit, by a suitably disposed spring.
The same letters of reference indicate corresponding parts in Figures 1 to 11.
In constructing an improved tumbler switch according to my invention, I take a
base a, of insulating material, such as china, with the separated pole terminals b,

page_text: passing through the bottom of the same, adapted to be bridged for making circuit by
a spring-sided or other contact maker such as c, mounted upon an arm c¹, which is
suitably insulated from, and turns at the rear upon, a pivot c², carried in an upright
bracket d, upon the summit of which is the seating or bearing d', of a ball centred
tumbler lever e, the lower end e¹, of which may be forked or cleft at e², with a small
roller e³, running within the cleft and wiping over the edge of a feather plate or rib c³,
provided along the top of the contact maker. This rib is V-shaped or provided with
two meeting inclined surfaces c, c, forming arins or stops against one or other of
which the rollered end of the tumbler impinges for rocking the said contact maker
into and out of its circuit-making positions. Thus, assuming the contact maker to
be in the break position shown in Figure 2, the operation of the tumbler lever causes
its rollered end to impinge against the forward arm or stop et, and so rock the contact
maker downwardly so as to bring its contact end between the terminals b, after which
the turning of the said lever in the reverse direction causes it to bear against the
other and rearward stop c', and rock the contact maker in the reverse direction to
break the circuit. This wiper rib or double-armed comb plate is preferably embedded
in a block of insulating material e disposed between the box-like sides c, of the
contact maker.
f is a traversing slide or shutter, made of insulating material and adapted to make
a to and fro movement within a guide race or clearance a¹, formed within the base of
the switch, and in such a direction that when traversed forwardly on the parts of the
switch being made to assume their "break" positions, it covers up or comes over the
terminals b, which lie within the said guide race a', and intervenes between them
and the lifted contact maker, thus interposing an insulating medium which efficiently
prevents the passage an arc from the one part to the other, whilst when the contact
maker is turned down to come between, and connect the terminals for again complet-
ing circuit, the said shutter is simultaneously and automatically withdrawn from over
the said terminals and permits of contact being made.
The forward movement of the insulating shutter is effected by means of a spring g
arranged to come between it and the opposite end a², of the guide race a', and to
have the double function of taking the said insulating slide over the terminals and
imparting a fly or quick break action to the contact piece through the medium of a
depending limb, connected with the contact inaker and engaging in a slot f¹, in
the slide and by which said limb or spur, the slide or shutter is withdrawn from over
the poles on a downward movement being imparted to the contact maker to take it
between the terminals.
The said shutter, whose movement, in one direction, is thus effected by a spring
and in the other, through the medium of the contact maker, may have inclined edges
coming underneath like inclined sides of its guide race, whereby it is prevented from
rising off the race along which it moves, and I wish it to be understood that I do not
confine myself to the particular mechanism herein described for communicating
motion to the shutter from the contact maker, as any suitable mechanical means
may be employed for the purpose, or the movement may be imparted from the
operating lever in either one or both directions.
In order to prevent the passage of an are direct from one terminal to the other a
block of insulating material at, formed integral with, or attached to the base, may be
arranged between them, but leaving sufficient space on each side for the wings of the
contact maker to come into.
Figure 12 represents, partly in elevation and partly in section, a modified form of
switch constructed according to my improvements, in which the shutterf, is made to
both insulate the poles b, from the contact maker c, and also from one another when
the circuit is broken, by making the said shutter of a T shape in section, with the
vertical web f1, (which may be guided in a groove a', in the bottom of the guide
race a) providing an interposed medium for preventing arcing between the two
terminals, as distinct from arcing between the poles and the contact maker, which is
obviated, as before, by the shutter f.

page_text: 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
First: In electrical switches, insulating the contact maker, when in its "break"
position, from the terminals or poles, by a slide or shutter of non-conducting
material, which is interposed, or made to intervene, between the said parts when the
switch is opèrated to break the circuit and withdrawn prior to the circuit being again
made, for the purpose herein set forth.
Secondly: In electrical switches insulating the contact maker, when in its "break"
position, from the terminals or poles, by a slide or shutter of non-conducting
material, which is interposed, or made to intervene, between the said parts when the
switch is operated to break the circuit, and withdrawn prior to the circuit being
again made, with the said shutter being moved in the one direction by a spring and
in the other through the medium of a tumbler or lever, substantially as and .for the
purpose herein described and set forth.
Thirdly-In electrical tumbler switches, the combination with a sliding shutter for
insulating the contact maker from the poles or terminals when the former is in
"break" position, of the means for operating the said contact maker consisting of a
comb plate or rib having inclines or projections such as c, c, against one or other of
which the lower end of the tumbler operates, substantially as herein described and
set forth.
Dated this 30th day of May 1899.
ALFRED WATSON...
By Henry Skerrett,
23, Temple Row, Birminghain, Agent for Applicant.