CUMIIE DI DUIFICATION
Year: 1899

page_text: Date of Application, 10th Mar., 1899-Accepted, 15th Apr., 1899
CUMI LEIE DI DUIFICATION
Improvements in Electrical Switches.
I, ROBERT FREDERICK HALL, of Ferndale, Church Road, Moseley, near the
City of Birmingham, 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:
In electrical switches of the tumbler type, faults frequently occur through bad
contacts and insufficient air break between the terminals, and in consequence of the
high voltage currents now in general use such faults are much accentuated.
The objects of the present invention are to overcome the above objections by
securing good contacts and greatly increasing the air break, and to prevent arcing
between the terminals or pole pieces, which latter object I propose to obtain by
introducing between the said pole pieces, a wall of insulation simultaneously with
the switching off of the current.
I will describe the application of my invention to a tumbler switch, although
I wish it to be understood that I do not confine myself to such an application as in
switches where very heavy currents are carried, I may arrange the handle for
making and breaking the contact in such a manner that the same forms a part of
the contact maker, but in such a manner as to secure a quick break action.
Figure 1 of the accompanying drawing represents a longitudinal vertical section
of a tumbler switch embodying my improvements, with the parts in their "make"
position.
Figure 2 represents a like section as Figure 1, but showing the parts in the
positions they assume when contact is broken with a wall of insulating material
intervening between the terminals, thereby preventing arcing.
Figure 3 is a cross section of Figure 1 upon the dotted line ; showing the
contact piece making connection between the poles.
Figure 4 is a further section of Figure 1 upon the dotted line r¹, with the parts
in the same position as in Figure 3.
Figure 5 represents, upon a somewhat reduced scale, the frame of the switch in
elevation and plan.
Figure 6 represents a plan and an elevation of one of the terminals.
Figure 7 represents an elevation and a plan of one of the connections by which
the lead wire is attached to the terminal.
Figure 8 represents two different views of the tumbler lever.
Figure 9 represents an elevation and a top edge view of the rocking arm,
which is made of fibre or other insulating material and carries the contact
maker.
Figure 10 represents an edge view and a plan of the plate on which the foot end
of the tumbler works.
Figure 11 represents an elevation of the china or like non-conducting base of
the switch, showing the pair of separated walls, into opposite holes in which the
ends of the terminals or pole pieces extend and between which the rocking carrier
of the contact maker works.

page_text: Figure 12 represents another view of the switch base, looking at the same from a
position at right angles to the point of view of Figure 11. The insulating cover is
shown in section and fitted in place in this view.
The same letters of reference indicate corresponding parts in the several figures
of the drawing.
a is the china or like base, having formed diametrally across the middle of it, a
gap or sinking a', within which the carrier b, of the contact piece c, works.
Directed along the opposite sides of the said gap, are a pair of separated walls or
ribs a², having coincident holes a³, at or near their ends; and through or into which
the end parts d', of the pole pieces d, take, with their inner sides d², preferably
extending slightly through the said holes and into the space between the walls a³.
The said pole pieces, which are-preferably of a laminated construction or made up of
a series of assembled plates as clearly shown in Figures 4 and 6, are made fast to
the base at d³, by connections e, into which the circuit wires take and are secured
by binding screws e¹, and the body parts d, of them come respectively on the outer
sides of the said ribs a² and are thereby insulated from one another. The contact
maker e, is in the form of a solid piece of metal passed through one end of the
rocking carrier b, and so arranged that when the parts are in their "make"
positions, its outer and naked ends c¹, which are the only parts of it not embedded
within or enclosed by the insulating material of its carrier, come against, and make
electrical connection with the presented parts, of the contacts or poles, which are
thereby bridged and current passes, but when the current is switched off by
operating the tumbler lever f, and thereby rocking the contact carrier b, upon its
joint pin or fulcrum 61, which is mounted in the framing g, of the switch, the parts
assume the positions shown in Figure 2, with the metal contact piece taken away or
clear of the poles, and with the lower parts 62, of the said carrier, which now forms
an insulating diaphragm, intervening between the said poles, so that by thus
partitioning off the said poles or terminals during the time that the switch is in
the break position, arcing is efficiently obviated.
in
The tumbler lever f; one arm of which extends as usual through the cover h,
is fulcrumed at f¹, to the framing and its lower and f², which may be rollered,
preferably works upon a small metal plate i, attached to the top arm of the
rocking contact carrier and having at the end nearest the joint of the said carrier,
a small heel or extension ¹, against which the toe of the tumbler impinges or
comes for rocking the carrier into a break position in the event of the spring j
not immediately operating to give a fly or quick break action.
The said spring j, is shown disposed between the underside of the insulating
carrier and the bottom of the gap within which it works and may be confined
between wings or sides formed by channelling the underside of the said arm to
receive the spring, but I wish it to be understood that I do not not confine myself to
this particular method of arranging the spring, as the same may be disposed to act
in any other manner which will provide a quick break action.
kare the holes in the base to receive the screws by which the switch is secured
in position.
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 electrical switches, interposing between the poles or terminals,
simultaneous with the breaking of the circuit, a diaphragm or partition of insulat-
ing or non-conducting material, whereby arcing between the poles is prevented,
which said insulating partition is automatically removed on the circuit being again
made.
Secondly: In electrical switches, the employment of a swinging or advancing
and retiring partition or diaphragm of. insulating material, adapted to work between
the poles or terminals of the switch and to be interposed between the same,
simultaneous with the circuit being broken and to be removed therefrom by the

page_text: act of operating the switch to again make the circuit, substantially as and for the
purpose set forth.
Thirdly: In electrical switches, the employment of a movable arm or carrier,
made of insulating material and provided with a metal contact piece, the arrange-
ment being such that when the switch is in its " make" position the said contact
piece is in electrical connection with the poles or terminals, but when the parts are
in their "break" positions, a portion of the insulating material of the said carrier is
interposed between the said poles.
Fourthly: An electrical tumbler switch as represented in the drawings, com-
prising a swinging contact piece carrier, made of insulating material with the
ends of contact piece being exposed on the opposite sides thereof, and a pair of poles
or terminals, with parts extending through holes or gaps in a pair of separated
and insulating walls and coming into the path of the contact piece, whose insulating
carrier works between the said walls and is so arranged that a non-conducting part
of it is interposed between the terminals when the switch is in its break position,
substantially as and for the purpose as described and set forth.
Dated this 9th day of March 1899.
ROBERT FREDERICK HALL,
By Henry Skerrett,
24, Temple Row, Birmingham, Agent for Applicant.