Improvements in Switches for Electrical Circuits
Year: 1888

page_text: 1, THOMAS PARKER of Elwell-Parker Limited, Commercial Road Wolverhampton
in the County of Stafford Electrical Engineer, do hereby declare the nature of this
invention to be as follows:-
-
This Invention relates to Improvements in Switches for Electrical Circuits and more
particularly for the circuits of tramcar motors deriving their supply of Electricity
from secondary batteries.
The Switch is intended by its operation to enable the whole of the cells of the
battery to be joined up in series; a portion of the cells to be included in the circuit
in series; the cells to be joined up in parallel series in differing sets of cells, and in
other desired combinations, and to enable the circuit to be opened or to be closed with
any desired combination of the cells of the battery.
A polygonal cylinder is mounted upon an axis with a cam having as many swells
as there are sides to the cylinder, and is provided with a handwheel or crank handle
for its rotation. One of the sides of the cylinder is left blank upon the other sides
there are fixed permanent metallic plates arranged and connected as required for the
various combinations or arrangements of the cells. Upon the permanent metallic
plates there are screwed radial metallic contacts or projections which may be removed
and renewed from time to time as required. The radial contacts close their circuits
or their portions of the circuits by passage in rubbing contact, between sets of double
brush contacts arranged parallel with the axis of the cylinder.
At the cam end of the cylinder there is a lever transverse to the axis of the cylinder
and provided with a finger or friction bowl engaging with the cam. This lever is
pivotted on one side of the axis of the cylinder and on the other side it normally closes
the motor circuit by a double brush contact. Upon the rotation of the cylinder
however, one of the swells of the cam acts upon the lever and moves it so as to open the
double brush contact in the motor circuit before the radial contacts on the cylinder
(which are in the same circuit) leave contact with their brushes. By this means

page_text: sparking at the radial contacts is prevented. The lever is connected by a rod to the
brake in such a manner that when the brake is put into action the lever is simul-
taneously moved and the motor circuit is opened.
One of the sides of the cylinder is left blank so that the circuits are all opened when
this side is turned into proximity with the set of fixed double brushes.
The recesses between the swells on the cam in combination with the finger or friction
bowl on the lever and the lover itself form a locking device to prevent the accidental
rotation of the cylinder.
The lover may be kept in position by means of a spring.

page_text: 1, THOMAS PARKER of Elwell-Parker Limited Commercial Road, Wolverhampton
in the County of Stafford, 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 switches for electrical circuits, and more particularly to
Switches for the circuits of Tram-car motors deriving their supply of electricity from
secondary batteries.
The object of these Improvements is to enable the whole of the cells of the battery
to be joined up in series, a portion of the cells to be included in the circuit in series,
the cells to be joined up in parallel series in differing sets of cells, and in other desired
combinations; and to enable the motor circuit to be opened or closed with any required
combination and arrangement of the cells of the battery.
The appended sheets of Drawings will enable my Invention to be more readily
understood and are hereinafter referred to.
Fig. 1 is a plan of a switch constructed according to these Improvements; Fig. 2
is a detail of the contacts for opening and closing the main circuit; Fig. 3 is an end
view; Fig. 4 is a side view of the cylinder; and Fig. 5 represents various arrange-
ments for connecting the battery circuits.
A polygonal cylinder A is mounted upon a spindle B together with a cam having
as many swells as there are sides to the cylinder. The rotation of the cylinder is
effected by means of a hand-wheel or crank which is not represented on the drawings.
One of the sides D of the cylinder is left blank; upon each of the other sides there
are fixed permanent metallic plates E E, arranged and connected as required for the
various combinations and arrangements of the cells which will be employed in practical
work or which may be desired. As represented in the Drawings, the cylinder has
six sides and the arrangements of the permanent metallic plates are shown in
Fig. 5 a, b, c, d, and e. The battery diagrams to the right of these Figures indicate
the resulting connections of the cells. Upon the permanent metallic plates there are
screwed or otherwise secured radial metallic contacts or projections F F, in such a
manner that they may be removed and renewed from time to time as required. These
radial contacts close their circuits or their portions of the circuits by rubbing contact
between sets of double contact brushes G G, arranged parallel with the axis of the
cylinder. At the cam end of the cylinder there is an arm H below the spindle and at
a right angle thereto. This arm is provided with a finger or bowl capable of
engaging with the cam, and is pivoted to one side of the spindle. The opposite end
of the arm is connected to the brake rod K, so that when the brake is put into
action, the arm is moved into the position indicated by dotted lines. At a right angle
to the arm there is fixed a double brush contact L Figs. 1 and 2, the two brushes of
which are parts of the motor circuit, so that when they are in metallic connection the
motor circuit is closed. and the reverse. Upon the arm there is fixed a metallic

page_text: contact block M in such a position that when the arm is in the position indicated by
full lines, the block makes metallic connection between the brushes L, and the motor
circuit is closed; while the motor circuit is consequently open when the arm is in the
position indicated by the dotted lines.
The motor circuit may be opened by the motion of the brake rod or by the rotation
of the cylinder.
When it is desired to alter the combination or arrangement of the cells then in
circuit, for some other combination or arrangement, the cylinder is rotated until the
radial contacts of the desired arrangement come into contact with the contact
brushes G G. By this rotation of the cylinder one of the swells of the cam acts
upon the arm H and pushes it into the position indicated by the dotted outline, thus
opening the motor circuit before the radial contacts F F (which are in the same
circuit) leave contact with their brushes. By this arrangement sparking at the radial
contacts is prevented.
One of the sides D of the cylinder being left blank, all the circuits are opened when
this side of the cylinder is turned into proximity to the brushes G G..
The recesses between the swells of the cam, in combination with the finger or friction
bowl on the arm and the arm itself form a locking device which prevents the accidental
rotation of the cylinder.
The arm may if desired be supported by a spring R tending to maintain it in the
closed position shown in full lines.
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.) A Switch for the circuit of a motor deriving its supply of electricity from a
secondary battery, constructed, arranged and operated substantially as and for the
purpose hereinbefore described.
(2.) In a Switch for the circuit of a motor deriving its current from a secondary
battery, the combination and arrangement of the brake rod K with the arm H,
the contacts L and M, and the cam C and the finger or bowl on the arm F; sub-
stantially as and for the purposes herein before described with reference to the
accompanying Drawings.
(3.) In an Electrical Switch, the combination and arrangement of a polygonal
cylinder with permanent metallic contact plates E E, removable radial contacts FF,
and double brush contacts G G substantially as hereinbefore described with reference
to the accompanying Drawings.
Dated this 5th day of October A.D. 1888.
WILLIAM E. HEYS,
Agent for the Applicant.