Improvements in Simple and Compound Switches for Electrical .Currents.
Year: 1888

page_text: Date of Application, 12th Dec., 1888
Complete Specification Left, 11th Sept., 1889-Accepted, 9th Nov., 1839.
I
PROVISIONAL SPECIFICATION.
Improvements in Simple and Compound Switches for Electrical
.Currents.
I, WILSON HARTNELL, of Benson's Buildings, Park Row, Leeds, in the County of
York; Electrical Engineer, do hereby declare the nature of this invention to be as
follows
This invention has reference to an improved mode of building up and working,
simple and compound switches, generally similar to those referred to in my former
patent on this subject, No. 6,487, A.D. 1886.
A good compound switch cannot be satisfactorily arranged unless some yielding
connections are introduced at the terminals of the circuits which are to be briged or
unbridged.
In my former patent, elastic brush-terminals served this purpose, and such have
proved very satisfactory..
Where however heavy currents have to be dealt with, and where the brush-
terminals are numerous, as they are in many of my compound switches, the cost'
is unduly increased by the magnitude of the brushes and by the great care that has to
be taken in bedding them not only to the surface of the bridges but also to that of
their holders or guides.
Moreover in switches for heavy currents the rise of temperature, which takes place,
even in the solid conductors, but more especially at the areas of contact, is higher than
with small currents, because the available cooling-surface is in general proportionately
smaller.
The object of my present invention is to reduce the cost of my compound switch
boards and keep down the temperature with heavy currents by reducing to a minimum
the number of brushes, or their equivalents, and the number of the adjustable surfaces
of contact; and also to adopt such a form as shall enable me to use high conductivity
copper bars, or simple copper forgings, for my terminals; in place of the cast brass
work at present used by me.
I carry out my invention as follows: Instead of using a solid bridge in connection
with elastic brush-terminals, I use an elastic brush-bridge (or its equivalent) with solid"
terminals.
"
By this means I simplify the terminal and abolish the adjustable contact surface
necessary in the,old arrangement of brush-holder.
The elastic plates (or wires). of the brush bridge may in almost every case be
continued right across, from terminal to terminal, without break of continuity.
Hence the cost of construction is reduced and the terminal contact faces which require
expensive workmanship are reduced to a minimum.
The terminals may be grouped as required to form the particular compound switch.
desired and their working faces may be, of different widths and lengths-i.e., certain
faces may be prolonged as required. The working faces may be plain, or curved, to.
suit the motion and action. of the bridge. In some cases the terminals may be in the
form of short cylinders, or poligons, with contact surfaces all round the circumference,
or round only a certain portion, as required.
:
The bridge (there may be any number) may be mounted on a slide, or on a spindle,
or an axis. In the latter cases it may be traverse lineally, or twisted into position,
or both, as in certain of my previous combinations.
The bridge, may consist of rectangular (more or less) plates bent so as to form the
equivalent of a pair of.brushes joined at the centre, and such a brush may be traversed
or twisted, between or against flat or cylindrical terminal faces.
"

page_text: The object of my present invention is to reduce the cost of my compound switch
boards and keep down the temperature with heavy currents by reducing to a minimum
the number of brushes, or their equivalents, and the number of adjustable surfaces of
contact; and also to adopt such a form as shall enable me to use high conductivity
copper-bars, or simple copper forgings, for my terminals, in place of the cast brass
work at present in use by me..
In order to fully explain my meaning I have annexed five sheets of drawings for
reference purposes.
"
I carry out my invention as follows:-Instead of using a solid bridge in connection
with elastic brush terminals, I use an elastic brush-bridge (or its equivalent) with
solid terminals.
By this means I simplify the terminal and abolish the adjustable contact surface
necessary in the old arrangement of brush-holder.
The elastic plates, or wires, of the brush-bridge may in almost every case be
continued right across, from terminal to terminal, without brake of continuity-as
shown on the drawings. Hence, the cost of construction is reduced and the terininal
contact faces which require expensive workmanship are reduced to a minimum.
I group my terminals as required to form the particular compound switch
desired for instance as in fig. 1 which shows in elevation, a pair of Compound
Spindle Switches, with lineal motion, arranged to suit a pair of dynamos working two
circuits on the three wire system. Here the bush bridges A¹ &c. are mounted on the
spindles B & B2 which work in guides at C. C. C. C. Each switch couples up both
at its positive and negative terminals-the two bridges being insulated one from the
.other. In case both dynamos were required to work, then both switches would be at
the top but in case either dynamo were sufficient to work both circuits then the
three wires must still remain in circuit although the switch of the second dynamo is
shut off. In the case illustrated the dynamo of the left hand switch is at work;
that of the right hand being shut off; the three wires being nevertheless in action.
The first dynamo is coupled to the terminal D₁ and the second dynamo to D²; from D¹
the current passes across the bridge A to the terminal D³ from whence it may be
led to a measuring instrument (not shown) and thence to the first circuit. It will be
seen that the current can also cross over the plug D³, travel to the terminal D where
it can cross the bridge As, from thence find its way to the connection D', and from
thence through a measuring instrument (not shown) to the other-the second
circuit.
The third wire carrying the return current common to the two circuits is coupled
at E, from whence the current can cross the bridge A' to the terminal E' and thence
back to the dynamo.
::
If both switches are lowered, both dynamos are entirely cut off. Suppose the right
hand switch to be raised, into action, with the left hand one remaining down (shut
off) then the current entering at D² would cross the bridge A to D and thence out
at D'; a portion would also travel up to 18 cross the bridge A¹ to D' and crossing
the plug D leave at the connection at D³. The return current would as before
enter at E, and afterwards pass over bridge A³ to E3 and thence to the dynamo. If
the plug Do be taken out then both switches are entirely separated. No contact must
take place where the connections pass one another above the plug. . As the friction of
the brushes may be heavy a lever is shown attached to each spindle and a suitable
catch may be arranged to fix the switches in any special position. I fit each bridge
with a sparking plate as shown at A', on the other bridges these are omitted on the
drawings in order to show the brushes clearly. This arrangement permits alterations
to be made without any possibility of error and without disturbing the lights.
Another example of a compound switch is given in fig. 2 which shows an elevation
of a switch board for a Compound Double-pole Spindle Switch together with a Cell-
regulating Brush Bridge arrangement for supplying two lamps circuits at different
distances those on the far circuit requiring a higher potential.
The dynamo is connected. to the terminal F which is shown bridged by the
brush A; the current passing forward through F to F³. This latter is connected with

page_text: the long terminal bar. F whereon slides a Brush-bridge, G₁ cominunicating with
the series of Cell-terminals numbered 58 to 49 thus by sliding this bridge along.
the terminal bar F4, the dynamo may be coupled up at any desired cell. The
wires F F &c. &c. shown running from each cell-terminal are supposed to lead
away to the respective cells. Brush-bridges are also arranged to slide along to other
terminal-bars F & F, the former communicating through its end terminal F with
the far circuit, whilst the latter, through its end terminal F, communicates with the
near circuit. It will be seen that the cell terminals 8 to 49 have each three faces
-numbered: (1) (2) & (3); on terminal 58-against which the three brush-bridges
may make contact, each brush being capable of being placed in any desired position.
On the cell terminals 48 & 46 the upper, terminals (1) have been omitted as not being
required, but terminal 47 has a special arrangement as follows:-Supposing.
something to be matter with the battery and it be desired to run the circuits direct
from the dynamo ;, then it is necessary to break the connection of cell-terminal 47
by uncoupling the link H, (its cell wire being thus broken) after which the dynamo
Bridge Gmust be brought against the end of 47, and the. lamp bridges G & G³
arranged to take the current direct from this terminal-(ie. not through the battery).
In the Bridges G, G & G³ by the side of the main brush is arranged a secondary
one g which is coupled one to the other through a résistance coil at g² to avoid
short-circuiting any of the cells. In fig. 3, which is a Sectional elevation-through. a
Bridge G, A is the brush bridge which has its plates arranged to travel sideways.
It couples up the terminal, (say (1).) direct across to the terminal bar F which is
supported by the bearer f. The brush-holding bracket 93 clasps the bar F, along
"which it is moved by the insulated handle g without coming in contact with the bar
.support f.
Reverting to the Spindle Switch --the negative current returns through the
terminal F and across the bridge A to the terminal F" and thence to the dynamo.
This Switch is so arranged that if it be pushed higher the bridge A will break
'contact with F10 and connect the terminal F2 to F thus permitting a measuring
instrument to be introduced. Both bridges A5 and A have an extra length of plates
for this purpose, the lower left hand corner of A being cut away so that the contact is
broken there when the spindle is raised for measuring purposes. To shut off the dynamo
the Spindle which is provided with a feather to prevent its turning round is lowered
until both bridges are withdrawn. The bridges, which are insulated one from the
other, here shown, are composed of plates arranged in the plane of motion, i.e.-they
move edgewise on: such a bridge is shown in transverse section in fig. 30, S being
the sparking plate.
In connection with the spindle switch-to prevent too strong a pressure being put
on the lamps are two safety catches J. J, which are thrust by light springs against
-the Spindle B³ so that the detents J1, in either case; when below the catches, holds
the spindle shown & prevents the bridging of the terminals. If however the Cell
Regulating Bridges G2 and G³ are brought towards zero, to terminal 46, the catches
being thus removed-then the spindle can be pushed up and the attendant can
afterwards move his cell regulating bridges back to such positions
-requisite..
as he find
Again another example for a compound switch is shown in figs. 4, 5, 6, 7, 8: the
first being an elevation, whilst the latter four are all transverse sections.
As figs. 1, 16, 17, 18, represent this same switch in another form-fig. 15,
being the elevation-the description of these may be taken together:
This class of switch is the same as that shown in elevation in fig. 3 of my former
patent No. 6487 of 1886. It here forms an example of my mode of coupling up by
elastic bridges any pre-arranged solid terminals, and has reference to the working of
an installation with a dynamo and a storage battery. The several requirements might
necessitate five different combinations of three switches, of which combinations any
may be required according to the object in view. The switch spindle (here for
simplicity's sake supposed to switch off and on at the positive end only of the circuit)
must have three. (to meet the case in point) bridges B¹; B & B³; circular (or

page_text: polygonal) in form, insulated from each other, and three pairs of terminals CC, C³
C, CC. Provision. is made for securing the spindle in five (to meet the case in
point) different positions (see fig. 8) 15 of a revolution apart, leaving it free to move
longitudinally. Each position corresponds to one of the required combinations.
The bridges, of suitable diameter, or size, must be cut away opposite the pairs of
terminals of the particular wire or wires which are not to be bridged across in that
given position. The cutting away has to be done to suit each of the five here-
mentioned positions: On turning the spindle round to the position already prepared
for a given combination, and pushing it forward, the proper terminals (and those
only) will be simultaneously bridged. Suppose the bridge-piece B' to couple the
dynamo to the battery, the bridge-piece B the dynamo to the lamps, and the bridge-
piece B³ the Cell Regulator to the lamps; then position 1 will allow the dynamo to
charge the Battery Position 2 will allow the dynamo to supply the lamps in
conjunction with the battery; Position 3 allows the battery alone to supply ithe
lamps; Position 4. allows the dynamo alone to supply the lamps; and position 5.
allows the dynamo to supply the lamps using the battery as a Regulator. Figs. 5, 6, & 7
are sections through the bridge pieces B₁ B2 & B3, and the small figures correspond
with the Figures in fig. 8. In fig. 4. the switch spindle is shown in position No. 2;
F is a fixed guide and F the changing stop. The spindles may be pushed up and
down by any suitable.means, E, E are the guides in which they work. Any other
number of combinations can be arranged for in like manner, the diameter, and sizes,
or number of polygonal faces of the bridge-pieces, being arranged to suit the number
of combinations. The negative ends may be similarly treated by doubling this
arrangement if both circuits are to be broken.
In applying the above description to figs. 15, 16, 17, & 18 it must be borne in mind
that a modification. is there introduced consisting of cutting away portions of the
solid terminals; the bridge, which is twisted, as before, to suit the requirements,
being a simple brush of any suitable class. An ordinary brush-bridge, as in fig. 31,
could be pushed between such prepared terminals.
Figs. 9, 10, and 11 are transverse sections of different brush-bridges (and their
terminals) all of which are shown as being able to be twisted off from between their
terminals, as well as being suitable for pushing between them..
Fig. 12 is a longitudinal view showing how, say for measuring purposes, a brush-
bridge may continue in contact with one terminal whilst passing across to another on
the opposite side.
Fig. 13 shows how a centrally mounted brush-bridge may be twisted so as to make
contact with any number of terminals arranged round it; and fig. 14 shows the same
in cross section.
"
Fig. 19 is an edge view of an " umbrella-like arrangement of dished plates,
preferably slit at the edges for greater elasticity:-a circle or a polygon could be
equally bad.
Fig. 20 is a transverse view of a circular brush with the plates arranged
tangentially.
Fig. 21 is a side view of the brush-bridge with straight plates resting on bevelled
edge terminals. Such may be raised out of contact, or twisted if the faces be coned,
or it may move lineally in a side direction.
[
Fig. 22 is a transverse view of a double bridge grasping terminals on either side.
Where circumstances permit it, this might be drawn out of circuit (end wise) on to
insulated guides of the same shape as the terminals and would then be self supporting
by its own gripping power. Any double gripping bridge could be arranged in the
same way. It will also twist off between its terminals if so arranged.
Fig. 23 is a transverse view of a circular terminal with a double brush-bridge
thrust therein.
Fig. 24 shows how a Wire-bridge can be wrapped round a spindle, and how one
terminal can be in one plane, and one in another. Such a bridge could be moved
lineally or twisted into different positions...

page_text: -
.
Figs. 25, 26 & 27 are respectively a transverse elevation; a plan, and a side
elevation of a small single switch of special arrangement with double.brush bridges.
K, K are the bridges, L, L, are the terminals, Mis the case, and N the spindle.
The spring, O, is arranged to thrust the spindle back and unbridge the switch as soon
as it is, released, but it will be seen to be held in check by a flat spring P which bears
against the washer O' against which 0-presses:
As soon however as the Spindle N is thrust forward, an incline N' thereon, which
works in in indentation in the spring, depresses the same, and in doing so thrusts it
out of the way of the washer, enabling the spring to throw the bridge out. The rest
of the switch calls for no special comment...
Fig. 28 is a transverse view..showing how the terminals may be inade to embrace
a double bridge.
Fig. 29 shows how a terminal which may be called solid is yet capable of being
adjusted.
on.
:
Fig. 30 shows a transverse view of a brush-bridge arranged to travel edgewise
Fig. 31 shows how, when required arrangements may be made to expand a brush-
bridge, such, say, as has become a slack fit. through wear & tear.
Where not specially. lettered the 'brushes are marked the terminals R, and the
sparking plates S. Where possible the sparking plate works on a separate face.
The working faces may be of different widths and lengths-.e. certain faces either
of the terminals or the bridges may be prolonged as required as shown in fig. 2 where
the terminal bars F, F & F may be of any length. Again in fig. 2 one face of the
bridge A is curtailed, whilst in fig. 12 the terminal is prolonged-the result being
the same.
The working faces may be plain,-i.e. flat as in fig. 1. or curved, as in
figs. 5 & 9 &c. to suit the shape, motion, and action of the bridge. In some cases the
terminals and bridges may be in the form of short cylinders, or polygons, or portions
thereof, with contact surfaces all round the circumference, as in the case of a brush
plug, such as in fig. 19 or 20, or round only a certain portion as in figs. 5, 6 and 7. &c.
as required.
The bridge (there may be any number) may be mounted on a slide-which slide
may form one long terminal as in fig. 2-or on a spindle as in fig. 1, or an axis, as
in fig. 13.
In the latter cases it may be traversed lineally, as in fig. 1, or, twisted into position
as in fig. 13, or both, as in certain of my previous combinations and as shown in
figs. 4, 15, &c.
The bridge may consist of a bundle of wires, as shown for example, in fig. 24-
although almost all could be formed of wires-or of plates, tuore or less rectangular,
.bent so as to form the equivalent of a pair of brushes joined at the centre, as in
fig. 31 &c. &c., and such a brush may be traversed as in fig. 2, along a bar, or
between terminals as in fig. 1, or twisted as in figs. 9, 10, 11, and 13,. between or
against flat or cylindrical terminal faces, as the case requires.
The brushes may be arranged with the plates traversing flatway or edgeway on, in
either direction, as shown in figs. 1, 2, & 30 &c.
The cylindrical bridge, see figs. 19 & 20, admits of being used as an elastic plug and
makes a contact in the manner. In fig. 4 the bridges shown are. of fig. 19 class cut
away to suit. A circular terminal and a brush are also shown in fig. 23.
A compound switch may be formed by placing several elastic bridges on a spindle
and then twisting them into position, as shown in figs. 4 & 15. When such bridges
are to make contact between or against the ends of the terminals both a twisting and
an end movement may be given, as in fig. 4.
2
In certain cases where contact is made against the ends of the terminals and when
both a longitudinal and twisting motion is used, one may be used to give a greater
pressure on the surface of contact after the bridge has been brought into position.
In fig. 15. the lever is used to draw down & fix the bridge, after which the screw at
the foot may be used to increase the pressure..

page_text: In some cases increased surface of contact may be obtained by making the bridge
grip the terminals on the opposite surfaces also see fig. 25, either 'longitudinally or
axially.
6.
Or the bridge-brushes may be embraced by the terminals, as in fig. 28. It must
be understood that mounting a series of brush-bridges on, say, for instance, a spindle
(even if the particular brush used were not new for a simple switch) would be an
effective way of building up one of my compound switches, an example of which is
given in fig. 15 the simple bridge of which is not new-neither is the simple bridge"
in fig: 11.
Sparking arrangements may be added by which the working contact faces may be
protected, more especially when the sparking plate is arranged to work on a separate,
face. In all the figs. S is the sparking plate in many cases shown in dotted lines.
.It cases where it may be undesirable to withdraw a brush backwards way, against
the teeth of the plates as it were, such a brush may be pushed forward out of action:
It can then be twisted narrow way on, and thus be drawn back; it will then only
want twisting. back once more and pushing forward. when next wanted for bridging
purposes.
15.
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. The Simplo Switch. formed of an elastic- Brush-bridge with adjacent solid
terminals, with or without Sparking-plates, substantially as described herein and
shown in fig. 1.
2. The construction and arrangement of Compound-switches, suited to the require-
ments of the three-wire system, with their terminals arranged after the manner
described & shown in fig. 1.
3. The construction and arrangement of Compound-switches with elastic brush
bridges in combination with an arrangement of solid terminals suited to the require-
ments of a Cell-regulating and Distributing Switch-board after the manner described
herein and shown in fig. 2.
4. An Elastic brush-bridge sliding on its own terminal bar after the manner
described and shown at G¹ in fig. 2.
5. Elastic brush bridges with the plates arranged to travel edgewise on, with or
without sparking plates, after the manner shown at A & A in figs. 2 & 30.
6. The safety arrangement connected with the detents J, J', substantially as
described and shown in fig. 2.
•
7. The construction and arrangement of compound switches consisting of elastic
brush bridges, specially shaped to meet certain pre-arranged positions, in combina-
tion with a series of solid terminals, after the manner described and shown in fig. 4.
8. Elastic brush bridges swivelling between solid terminals, with faces curved to
suit the movement, with or without sparking plates working on surfaces of their
own, substantially as shown in figs. 9 & 10.
9. Elastic Brush Bridges and solid terminals such as could be easily prepared in
a turning lathe, pushed, or pulled, in and out, endwise substantially as in
figs. 9, 10, & 11.
10. The arrangement of an elastic brush bridge working between terminals of
different lengths, which may be flat or curved, substantially as, shown in fig. 12.
11. The arrangement of an elastic brush bridge with flat plates, arranged as shown,
mounted on a central axis whether the brush runs across or uses the axis as a terminal,
in combination with solid terminals presenting their turned up ends to the said brush,
substantially as shown in figs. 13 & 14.
12. The construction and arrangement of compound switches after the manner set
out in fig. 15 consisting of a series of elastic brush bridges (of any suitable type)
mounted on a spindle in different planes, and brought into contact between, or
against, special solid terminals shaped to suit the given requirements.

page_text: 13. The umbrella,shaped circular. or polygonal elastic bridge or, plug-in whole or
in part substantially as described, and shown in fig. 19.
14. The circular bridge or plug-in whole or in part-substantially as described
and shown in fig. 20.
15. The elastic brush bridge and terminals substantially as described & shown in
fig. 21, whether raised, or twisted, off or on, with or without the sparking piece.
16. The elastic brush bridge and terminals substantially as shown in fig. 22 with.
or without the sparking piece, whether twisted; or moved lineally.
ส
17. The circular solid terminal and internal elastic brush bridge or plug,
substantially as shown in fig. 23.
18. The double-armed Gripping Switch shown in figs. 25, 26, & 27,
the trigger gear, substantially as described and shown.
with or without.,
19. The arrangement of double bridge embraced by solid terminals, substantially as
described & shown in fig. 28.
20. The mode of adjusting a terminal otherwise "solid" as shown in fig. 29.
21. The mode of adjusting a brush bridge, substantially as described and shown in
fig. 31.
ני
"
WM. SNOWDON,
9, Beckett's Bank Chambers, Leeds, Yorks., Agent for the Applicant. .