Improvements in Multiple Point Switches suitable for use in Electric Lighting.
Year: 1893

page_text: Date of Application, 27th July, 1893—Accepted, 23rd Sept., 1893.
COMPLETE SPECIFICATION.
Improvements in Multiple Point Switches suitable for use in
Electric Lighting.
We, FRANCIS HENRY NALDER, HERBERT NALDER, CHARLES WILLIAM
SCOTT CRAWLEY, and ALFRED SOAMES, all of 16 Red Lion Street, Clerkenwell,
in the County of Middlesex, Electrical Engineers, 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 is more especially applicable to double circuit multiple contact
regulating switches such as are employed in electric lighting to regulate the
charging and discharging of secondary battery cells and simultaneously to regulate
the supply of current to an external circuit in which the current is expended and
utilised.
Such switches have two hand levers and a series of insulated contact blocks so
arranged between the levers that either lever may be caused to make contact with
any one of the several contact blocks.
As these instruments have been heretofore constructed the two levers have been
mounted on separate axes placed widely apart so that the levers although in
the same plane may pass each other without interference. Thus arranged these
switches necessarily occupy much space, they are costly to construct, and the
handles of the levers are not so convenient for working and locking as they
might be.
To obviate these objections we mount the two switch levers on the same axis so
that they move in parallel planes at only a short distance apart but sufficiently far
to admit the contact blocks between them.
The contact blocks radiate from the centre or axis and the contacts are made by
the two switch levers on the opposite sides of the blocks.
The improved construction admits of all the contact blocks being of the same
pattern which reduces the cost of construction.
In order that our invention may be fully understood and readily carried into
effect we will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a transverse vertical section of a double circuit multiple contact
switch in accordance with our invention.
Figure 2 is a longitudinal and vertical section with parts removed.
Figure 3 is a plan also with parts removed, and
Figure 4 is a side elevation of one of the lever handles.
Figure 5 is a diagram illustrating the arrangement of the circuit connections.
aa is a slab preferably of slate serving as a foundation; this slab will usually be
fixed in a vertical position, but in some cases a horizontal position may be more
convenient. is a cast iron frame bolted to the slab a by bolts. The fraine
carries an inner frame having four radial arms which support the pin or
axis c on this the hand levers d d are mounted and are able to turn freely.
Each pair of arms 662 also carries two concentric arcs and which are all
part of the inner frame or casting. The larger arcs ³ ³ carry between them the
insulating arc e of vulcanised fibre. are clamping bolts by which the
insulating arc e is held securely in its place. fff are a series of gun metal contact.
blocks, all of the same form; they are fixed by the bolts to the are of
vulcanised fibre e. gg are connectors which when the apparatus is used in the

page_text: manner already referred to, as a regulating switch, are connected each with one
of the cells of a secondary battery; say for example the 51, 52, 53 and so on to the
58 cell. We need not explain the connections in detail for these are already well
understood. hh are two arcs of vulcanised fibre and ii are similar gun metal
arcs; they are fixed upon the arcs of the frame by bolts which pass
through vulcanite ferrules h h so that in each case the metal arcs ii are insulated
from the frame. One of the arcs i is connected by a conductor with the dynamo,
the other by a conductor with the external circuit which directly or indirectly
supplies the lamps.
Each lever d carries a "brush" & composed of curved plates of sheet copper
superposed the one on the other. The brush is insulated from the lever by a
sufficient thickness of vulcanized fibre and the parts are clamped together by
bolts which pass through vulcanite ferrules let into recesses in the
lever. One extremity of each brush rests as will be seen on the gun metal arc i
and the other extremity upon one or other of the contact blocks ff in each case
completing a circuit. Each of the hand levers d is provided with a locking bolt d'
which when the hand lever is grasped is lifted and then the lever is free to be
moved to shift the brush & from one contact block to another. When the lever is
properly placed and the handle is released the spring a forces the nose of the bolt
into one or other of a series of holes formed on the peripheries of the
arcs to receive the bolts d'; thus the same ares of the frame which support
the contact blocks serve also for the locking of the hand levers. The placing of
the lever in a proper position and its secure retention when there are thereby
ensured.
Sometimes with a view to prevent sparking it may be advantageous to provide
each handle with two brushes connected through a resistance in such manner that
the circuit is never opened; this is a well known device which we need not fully
describe.
In the term "brushes" we include any conductor attached to the lever handle
and serving to carry the current between fand-i
Other insulating materials may be substituted for those herein named and other
variations in the details of construction may be made without departing from our
invention. The double multiple contact switch herein described is obviously
suitable for varying the resistances in the circuits; if this be required.
The arrangement above described may (but not advantageously) be varied by
arranging the hand levers d d to move in planes inclined somewhat the one to the
other, in place of in parallel planes; or again the hand levers may be arranged to
rotate about centres at a short distance apart. These modifications we desire to
embrace within our Patent.
The diagram Figure 5 illustrates circuit connections which are appropriate for
use in connection with a lighting circuit, a secondary battery and a dynamo. The
switch indicated in this diagram is not one of our improved construction for this
owing to its compactness does not readily admit of the connections being diagram-
matically represented.
The parts marked C. D. F and I in the diagram are the representatives of
those marked with the corresponding small letters in the other figures of the
drawing. X represents the dynamo. Y the secondary battery and Z the lighting
circuit.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is-
1. A multiple contact switch substantially as described having two hand levers
moving concentrically in parallel planes and by "brushes" making contact with
one or other of a series of contact blocks situate between the hand levers.
2. A multiple contact switch substantially as described having two hand levers

page_text: moving in different planes and by brushes making contact with the opposite faces
of a series of like contact blocks situate between the hand levers.
3. A multiple contact switch substantially as described.
Dated this 27th day of July 1893.
CARPMAEL & Co.,
Agents for the Applicants.