Improvements in Simple and Compound Switches for Electrical Currents.
Year: 1886

page_text: Date of Application, 14th May, 1886.
Complete Left, 14th Feb., 1887.
Complete Accepted, 15th Mar., 1887.
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 my invention for IMPROVE
IN SIMPLE AND COMPOUND SWITCHES FOR ELECTRICAL CURRENTS, to be as
MENTS
follows:-
In switches for electrical currents the surfaces through which the current passes
must be in good contact to prevent "sparking "-otherwise injury or destruction of
the switch follows.
In ordinary switches with rigid surfaces-especially for heavy currents-it is
sought to obviate this danger by large areas of apparent contact, massive construction,
and good and expensive workmanship: but in spite of this they get out of order too
easily, by the springing out of line of the insulating supports, by wear and tear, and
by grit and dirt getting between the surfaces.
Where there are more than two pairs of surfaces the difficulty and expense of
making a good compound switch is so increased that independent switches are
preferred.
In my improved switches one of the surfaces 's formed by the ends of a metallic
brush, or bundle of thin plates, by preference solu ored together at the further end-
projecting sufficiently beyond its support to leave it elastic. This brush is placed
obliquely, say at an angle of 45°, to the other surface of contact, which latter is rigid
(or at any rate need not be elastic), and on being moved past the brush it springs
each plate sufficiently to cause them to severally press against the rigid surface-
A good contact is thus made over almost the entire area, and this notwithstanding
any irregularities of surface or position, or the presence of any ordinary grit or dust.
These brushes are so fixed (preferably by a screw or wedge in a suitable terminal
or support) that they may be not only easily withdrawn for examination and prompt
repairs, but also pushed forward to take up wear. A comparatively small brush will
carry a large current. The rigid surface, (so called) which is moved past the brushes
may be curved-moving round a centre, or straight-moving in a right line-or

page_text: radially. A large number of brushes may be placed in a comparatively small space,
above, below, or around the rigid surface-in any way found convenient.
This simplicity of construction combined with its trustworthiness of action is
specially useful for main switch boards where several switching operations have to be
done in a certain order, or where certain combinations are to be thrown off and on
under conditions where errors in proceedure may cause failure or accident. In such
cases the usual system of separate switches necessitates skilled and experienced
attendance, but with my arrangements of compound switches these operations or
combinations cannot be carried out otherwise than correctly.
A few examples will best explain my switch and method of compound arrange-
ments: In an ordinary switch-board, say, with several independent circuits, each
arranged to be switched off and on, both on the positive and negative wires, I make
each switch consist of a spindle, or bar, carrying two metal bridge-pieces, insulated
from each other, arranged with terminals, carrying the obliquely mounted brushes,
on either or any side of each bridge-piece; thus, when a spindle is thrust forward the
bridge-pieces connect up the respective pairs of brush-terminals, and when withdrawn
both circuits are broken. If a current measuring arrangement is required a fifth
brush-terminal is added, say, near the positive brush-terminal which is connected to
the dynamo. Such a position is given to these two brushes that upon moving the
spindle a little further forward the neighbouring bridge-piece first touches the
measuring brush and then breaks contact with the former positive-brush, but without
breaking contact with any of the other brushes. Such a switch-board may contain
a large number of brush-terminals, all of which may be absolutely relied upon, and
they may be arranged in any desired clusters round any desired number of switch
spindles for example--in groups of five, as above described.
For an example of a switch-board illustrating several pre-arranged combinations of
switching operations, I now take one for working an installation with a dynamo and
storage battery. The several requirements might necessitate five different com-
binations of three switches, of which combinations any may he 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) must have three (to meet the case in point)
bridge-pieces, circular or polygonal in form, insulated from each other, and three pairs
of brush-terminals. Provision is made for securing the spindle in five (to meet the
case in point) different positions, of a revolution apart, leaving it free to move
longitudinally. Each position corresponds to one of the required combinations. The
bridge-pieces, of suitable diameter or size, must be cut away opposite the pairs of
brush-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 brush-terminals (and
those only) will be simultaneously bridged. Any other number of combinations can
be arranged for in like manner, the diameter, and sizes, or number of the polygonal
faces of the bridge-picces, being arranged to suit the number of combinations.
The first described switch board may readily be arranged for two or more inde-
pendent dynamos-(as sometimes used for ship lighting and other purposes) which
are each to be capable of working any circuit without the chance of being coupled to
each other. For this purpose the switch spindles are made sufficiently long and the
bridge-pieces are traversed forward to fresh pairs of brush-terminals connected to the
second dynamos, or vice versa.
Many other combinations may be conveniently made on this spindle-switch
principle such as a switch to throw off and on cells of a storage battery. This latter
is perhaps more conveniently made by grouping the brush-terminals in an are of a
circle and using a straight bridge-piece with a radial movement to couple them up
successively to its central terminal.
Where a number of circuits have to be opened and closed in certain succession, a
series of brush-terminals grouped in an are of a circle may come in successive contact
with a quadrant arm forming the (so called) rigid conducting surface.
In this case

page_text: each independent circuit has its own brush-terminal placed in the order required. Or
where it is desired to successively remove or introduce certain resistance coils into any
circuit the same arrangement is available. The successive resistances are coupled in
the order required between adjacent brush-terminals and are therefore cut out of circuit
as the quadrant arm couples their brushes, or vice versa. Both these last operations
may be carried out in this form of switch by providing a sufficient number of brush-
terminals.
In coupling up dynamos in parallel a quadrant switch for each dynamo may be
used as last described, insuring switching off or on of either dynamo to the circuit
by one switch movement. By cutting a recess in the quadrant, near the positive
brush-terminal connected to the dynamo, it may be arranged that when this recess is
moved and brought under this brush-terminal, another brush-terminal connected with
a measuring instrument is brought into contact. Thus a series of successive operations
can be performed with ease and safety at one operation whereas with separate
switches and unskilled attendance errors might arise which would cause great damage.
Obviously many other combinations might be arranged beyond such as I have
enumerated but the principle underlying the whole will be understood.
The spindle arrangement may be replaced by a sliding bar: thus a wooden slide
with suitable metal facings and brush-terminals would form a convenient switch for
measuring the poniential from several different places-or for measuring the current
through several independent circuits which must be incapable of accidental connection.
Although the great advantage of this form of switch, with elastic brush-terminals,
appears to be for large currents, yet the construction may be applied to switches of
small size for single currents.
In order to break contact quickly I introduce, wherever possible, a mechanical
means for rapidly withdrawing the bridge-piece. This may be accomplished by a
spring and trigger thus-a sliding handle slips over the trigger when the latter falls
into the place prepared for it when holding the handle against the spring; afterwards
when withdrawing the handle, the trigger is released and the spring shoots the
bridge-piece rapidly out of contact. The whole arrangement is such that should the
spring fail to act the ordinary hand pressure for withdrawing the bridge-piece
accomplishes the purpose, though not so rapidly.
•
In like manner I introduce in the quadrant and other arrangements corresponding
means for shooting the bridge-piece rapidly out of contact-when moving from one
position to another.
WILLIAM SNOWDON,
9, Beckett's Bank Chambers,
Leeds, Yorkshire,
Agent for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in Simple and Compound Switches for Electrical
Currents.
WILSON HARTNELL, of Benson's Buildings, Park Row, Leeds, in the County of
York, 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 :-
In switches for electrical currents the surfaces through which the current passes
must be in good contact to prevent "sparking"
"-otherwise injury or destruction of
the switch follows.
In ordinary switches with rigid surfaces-especially for heavy currents-it is
sought to obviate this danger by farge areas of apparent contact, massive construction,
and good and expensive workmanship: but in spite of this they get out of order too
easily, by the springing out of line of the insulating supports, by wear and tear, and
by grit and dirt getting between the surfaces.
Where there are more than two pairs of surfaces the difficulty and expense of
making a good compound switch is so increased that independent switches are
preferred.
In my improved switches one of the surfaces is formed by the ends of a metallic
brush, or bundle of thin plates, by preference soldered together at the farther end-
projecting sufficiently beyond its support to leave it elastic. In some cases, however,
it may prove better to leave some or all of the plates loose, for the purpose of
adjustment. This brush is placed obliquely, say at an angle of 45°, to the other
surface of contact, which latter is rigid (or at any rate need not be elastic) and on
being moved past the brush it springs each plate sufficiently to cause them. to severally
press against the rigid surface-a good contact is thus made over almost the entire
area, and this notwithstanding any irregularities of surface or position, or the presence
of any ordinary grit or dust. Of course brushes might be arranged to make contact
with other brushes.
These brushes are so fixed (preferably by a screw or wedge-in a suitable terminal
or support) that they may be not only easily withdrawn for examination and prompt
repairs, but also pushed forward to take up wear. A comparatively small brush will
carry a large current. The rigid surface (so called) which is moved past the brushes
may be curved-moving round a centre, or straight--moving in a right line-or
radially. A large number of brushes may be placed in a comparatively small space,
above, below, or around the rigid surface-in any way found convenient.
The simplicity of construction combined with its trustworthiness of action is
specially useful for main switch boards where several switching operations have to be
done in a certain order, or where certain combinations are to be thrown off and on
under conditions where errors in proceedure may cause failure or accident. In such
cases the usual system of separate switches necessitates skilled and experienced

page_text: attendance but with my arrangements of compound switches these operations or
combinations cannot be carried out otherwise than correctly.
A few examples will best explain my switch and method of compound arrange-
ments, and to this end I have annexed seven sheets of drawings. The same letters
refer to the same parts in all the figures as far as possible: In an ordinary switch-
board, say, with several independent circuits, each arranged to be switched off and on,
both on the positive and negative wires, as shown on Figs. 1 & 2, I make each switch
consist of a spindle, or bar A, carrying two metal bridge-pieces B1 and B2, insulated
from each other, arranged with terminals, carrying the obliquely mounted brushes
C2, C3, C³, and C, on either or any side of each bridge-piece; thus, when a spindle is
thrust forward the bridge-pieces connect up the respective pairs of brush-terminals,
see Fig. 1, and when withdrawn both circuits are broken, see Fig. 2. If a current
measuring arrangement is required a fifth brush-terminal C³ is added, say,
near the
incoming positive brush-terminal which is connected to the dynamo. Such a position
is given to these two brushes and that upon moving the spindle a little further
forward the neighbouring bridge-piece B' first touches the measuring brush and then
breaks contact with the former incoming positive-brush, but without breaking contact
with any of the other brushes so as not to shut off the lights. Such a switch-board
may contain a large number of brush-terminals, all of which may be absolutely relied
upon, and they may be arranged in any desired clusters, in any positions, and in any
number round any desired number of switch-spindles-for example-in groups of five,
as above described, taking care not to place them too near one another.
For an example of a switch-board illustrating several pre-arranged combinations of
switching operations, I now take one for working an installation with a dynamo and
storage battery, see Fig. 3. 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) bridge-pieces B'. B², & B³, circular or polygonal in form, insulated from
each other, and three pairs of brush terminals C₁ C², C³C, C³ Cª. Provision is made
for securing the spindle in five (to meet the case in point) different positions, see
Fig. 7. 1 of a revolution apart, leaving it free to move longitudinally. Each position
corresponds to one of the required combinations. The bridge-pieces, of suitable
diameter or size, must be cut away opposite the pairs of brush-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 herementioned positions. On
turning the spindle round to the position already prepared for a given combination,
and pushing it forward, the proper brush-terminals (and those only) will be simul-
taneously bridged. Suppose the bridge-piece B¹ to couple the dynamo to the battery,
the bridge-piece B2 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 the 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. 4, 5, & 6 are sections
through the bridge-pieces B1, B2, & B3, and the small figures correspond with the
Figures in Fig. 7. In Fig. 3. the switch-spindle is shown in position No. 2. F is a
fixed guide and F the changing stop. In all the spindle switches 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.
This arrangement may be modified to suit the case of a circuit which is required to
be coupled to either of three dynamos without the possibility of connecting the
dynamos.
The first described switch board may also readily be arranged for two or more
independent dynamos (as sometimes used for ship lighting and other purposes) which

page_text: are each to be capable of working any circuit without the chance of being coupled to
each other. For this purpose the switch spindles are made sufficiently long and the
bridge-pieces are traversed forward to fresh pairs of brush-terminals connected to the
second dynamos, or vice versa. Fig. 9. shows such an arrangement by which either
of several dynamos (here taken as three) may be coupled to a circuit, and the current
measured if desired. The three brush-terminals C, O, and C3 are connected to three
independent dynamos, say at their positive terminal, whilst the brush-terminals C4, C³,
and are attached to the lamp circuit. The negative of the circuit is attached to the
brush terminal C; whilst the negative terminals of all the dynamos may be connected
and joined to the brush terminals C. The brush C is for measuring the current.
The bridge B can be unlocked and moved into different places on the spindle to suit
brushes and C³, and C3 and C. The other bridge B2 is here shown fixed to the
spindle, which must be insulated from B. When the spindle is drawn down the
negative is broken and then the movable bridge B₁ may be altered to suit the next
requirements.
Many other combinations may be conveniently made on this spindle-switch
principle such as a switch to throw off and on cells of a storage battery as shown in
Fig. 8.
Here the brush-terminals to C represent so many cells of a storage.
battery. The bridge B is moved to the position required and is there fixed by any
suitable locking catch as shown at E¹. The terminal C leads the current forward.
This latter is perhaps more conveniently made by grouping the brush-terminals in an
are of a circle and using a straight bridge-piece B with a radial movement to couple
them up successively to its central terminal, as shown on Fig. 12. The current is led
led off from the axis of B₁, and the brush-terminals C to C (and others if required)
are connected with the cells which are to be coupled up.
"
Fig. 10 shows a group of current measuring brush-terminals arranged-in this
case in diametrically opposite pairs, round a central bridge which may be swivelled
so as to connect any of these pairs. The central swivelling bridge has its terminal 131
insulated from B2 thus the current may be passed through a measuring instrument in
passing from one to the other.
Fig. 11 shows an arrangement of a Battery Charging switch. All the brushes are
concentrically arranged round a swivelling central bridge carrying the two insulated
bridges B and B. The brush-terminal is here supposed to be connected to the
positive of the dynamo, whilst the axis of B2 is connected to the negative. When the
bridge connects the pair of brushes C and C³, the first half of a battery is supposed
to require charging; when C and are connected the latter half of the battery is
charged; and when moved to connect C & C², the whole battery is coupled up for
charging.
Fig. 13. is a Lighting switch, arranged in a somewhat similar way to the last.
Here the brush terminal C is supposed to be coupled with the positive of the dynamo,
and with the negative: 03 with the positive of the battery, and C with the
negative. The bridge B couples up with the brush C5 which leads to the lamps,
whilst the axis of B couples the negative of the lamps to either of the terminals C
and C.
Where a number of circuits have to be opened and closed in certain succession, a
series of brush-terminals grouped in an arc of a circle may come in successive contact
with a quadrant arm forming the (so called) rigid conducting surface, see Fig. 14.
In this case each independent circuit has its own brush-terminal placed in the order
required. Or where it is desired to successively remove or introduce certain resistance
coils into any circuit the same arrangement is available. The successive resistances
are coupled in the order required between adjacent brush-terminals and are therefore
cut out of circuit as the quadrant arm couples their brushes, or vice versa.
these last operations may be carried out in this form of switch by providing a sufficient
number of brush-terminals.
Both
In coupling up dynamos in parallel a quadrant switch for each dynamo may be
used as last described, insuring switching off and on of either dynamo to the circuit
by one switch movement, see Figs. 14 and 15. By cutting a recess in each quadrant,

page_text: near the positive brush-terminal, connected to the dynamo, it may be arranged that
when this recess is moved and brought under this brush-terminal, another brush-
terminal connected with a measuring instrument is brought into contact.
Figs. 14 & 15 show the two quadrants A. A for coupling up two dynamos in
parallel. In each figure the brush CS is coupled to its own dynamo ; C is coupled
to the positive ends of the shunt wire is connected to the positive main cable:
Cis the measuring brush in each case. The intermediate brush-terminals are
coupled to each other through resistances so as to prevent damage to the dynamos if
the switch be turned off with the full load on. On turning off the switch, when the
quadrant leaves the eighth brush the current is shunted through say about an ohm: on
leaving the seventh brush the current is shunted through say an additional two ohms;
on leaving the sixth brush the main current, now reduced, say, to 30 amperes,
is broken. When the quadrant leaves the fifth brush the dynamo shunt current is
shunted say through 30 ohms and on leaving the fourth brush it is shunted through
say an additional 30 ohms and on leaving the third brush the dynamo shunt current
is broken. To start the first or either dynamo, its switch must be placed in the
upright position shown, thus connecting its shunt wire with its positive pole. The
second dynamo started becomes fully excited when its quadrant switch has reached
the fifth brush, which connects its shunt to the already positively excited cable.
Thus a series of successive operations can be performed with ease and safety by one
movement whereas with separate switches and unskilled attendance errors might arise
which would cause great damage.
A modification of Fig. 8 with a solid plunger instead of the narrow bridge B' could
be made to do similar work to this quadrant arrangement.
Obviously many other combinations might be arranged beyond such as I have
enumerated but the principle underlying the whole will be understood.
:
An example of a resistance introduced by sliding a bridge, quadrant, or bar forward
from brush to brush is shown in Fig. 15, where C, C, C³, are brush-terminals
connected through resistance coils to the intermediate terminals c¹, c², c³ respec-
tively. If C, C, C &c. be connected to the successive cells of a battery then the
Bridge B. may be moved along without short-circuiting any of the cells.
The spindle arrangement may be replaced by a sliding bar: thus a wooden slide
with suitable metal facings and brush-terminals would form a convenient switch for
measuring the potential from several different places or for measuring the current
through several independent circuits which must be incapable of accidental
connection.
The terminals to hold and guide the brushes may be conveniently made cylindrical,
see Fig. 17, with a slot for inserting the brush; the brush may be fixed by means of
a set screw or by a key, see Fig. 22, or the terminal may be split and the brush
clipped by a nut on a taper thread, see Fig. 18, or by a pinching screw, Fig. 19; this
latter is not a cylindrical terminal. When required the brush may stand in any
position or relation to its support, for instance transversely, see Fig. 20. or it may be
clipped or bolted to a flat surface, see Fig. 21.
For some purposes brushes may be grouped together side by side as in Fig. 24, or
in sets adjacent to each other as in Fig. 23; and the brushes independently fixed
so as not only to be capable of independent adjustment but of replacement or refitting
without disturbing the current that may then be passing through such a group.
The effect of sparking may be localized by projections at any arranged part on the
outer plate of the brush Fig. 22 by setting the brush obliquely, fig. 25; or by using
a separate sparking brush placed in advance. Any destruction of the brushes from
sparking may be remedied by making the outer plate or plates independently
adjustable, thus saving the refitting of the whole.
In Fig. 9. if it were deemed desirable to switch off the negative and yet keep them
separate, the arrangement on the positive side might be duplicated on the negative
and the sliding bridges connected-though insulated from each other.
The class of switch shown in Fig. 3. might have all its brushes placed in one

page_text: transverse plane, for certain purposes, and the one bridge might be twisted round to
suit the desired connection-this twisting could only be done when drawn back off the
fixed slide F.
In order to break contact quickly I introduce, wherever possible, a mechanical
means for rapidly withdrawing the bridge-piece. This may be accomplished by a
spring and trigger thus, see Figs. 1, 2, 3 and 9-A sliding handle H slips over the
trigger J, when the latter falls into the place prepared for it for holding the handle
against the spring K; afterwards, on withdrawing the handle, the trigger is released,
and the spring shoots the bridge-piece rapidly out of contact. The whole arrange-
ment is such that, should the spring fail to act, the ordinary hand pressure for with-
drawing the bridge-piece accomplishes the purpose, though not so rapidly-Fig. 9.
has the trigger Jin a modified form. An india-rubber Washer I is introduced to act
as a buffer against the fixed bearing E.
For rapid switching off a quadrant switch can be provided with a sector plate S,
having waved notches or depressions corresponding with the number of brushes, into
which depressions a spring K, secured to the switchboard presses a roller.-Before
the contact is broken the roller reaches the highest part of its path and then quickly
descends and switches off, as shown at Fig. 26.
Another method of compelling the movement to be quickly made step by step is by
a stop piece S¹, which traverses a zigzag, or preferably, a stepped path-see Fig. 27,
wherein the stepped path is shown in the guide S2, secured to the switch board. The
stop piece S¹ is here shown acting as the handle. In order to move the switch from
step to step it is necessary to alternately push in or pull out the stop piece transversely
to the path of the quadrant. The stop S¹ is mounted on a steel spring K², which
holds itself in the central line shown in Fig. 27 but it is so proportioned as to yield to
one side or the other when pushed or pulled. As the spring K' acts in one direction
only it must be arranged to do the switching off as being the most important
movement.
A single-acting contact breaker may be applied to any fair sized spindle switch by
turning a series of grooves and connecting them by longitudinal ones which may he
conveniently arranged to form steps preferably spiral as in Fig. 28. Such a spindle
is provided with a spring having a range enabling it to traverse the spindle from the
first to the last groove. By compressing the spring by the handle and then fixing it
by engaging a stop piece S in one of the desired grooves S2 the spindle is put into
action. A series of twists will then make it break contact, in the rapid manner
required, with such brushes as are arranged.
Where a rapid movement is required in both directions a handle H must be made
free to slide on the spindle longitudinally, a spring being fixed therein so that a
movement of the handle in either direction compresses the spring. On pressing the
handle forward (keeping on the pressure) and turning it until a longitudinal recess
comes in line with the stop piece S¹ the spindle will be shot forward by the spring to
the next recess and so on.
The reverse movement is brought about by drawing back the spring handle.
This principle may obviously be modified to suit the quadrant switch. It is
immaterial whether the stop piece be attached to the moving part or to its fixed
support.
For some purposes several spindle or sliding switches may be coupled together;
and that in such a manner that some are free to move certain distances before moving
the others. In like manner several quadrants may be coupled or superimposed.
In some cases a spindle arrangement may be as it were locked fast until certain
other switches which require a prior movement have released such catch or lock.
Switches for small circuits may be made on the same principle as those for main
switch boards, with single or double poles, except that by preference they are placed in
cases of incombustible non-conducting material. In some cases where it is convenient
to push the bridge on or off by traversing the spindle from either end, as in fig. 29
the handle H is fixed to the spindle. On pushing the spindle forward the trigger J

page_text: (which may be modified in several ways) locks a sliding piece T against which the
spring K presses. On pushing back the spindle the trigger J withdraws and the
spring K is then free to shoot out the spindle and its bridge-piece B.
A switch with a removable bridge intended to break a circuit and shunt the current
thro a new circuit is shown in fig. 30. The removable insulated bridge-piece B' & B²
are inserted between the brushes C & C to divert the current say thro an arc lamp
a current meter, or a resistance &c.-On withdrawing the bridge-piece the brushes
spring into contact again and the current flows on as before.
A switch with a removable bridge is shown in fig. 31 where the positive & negative
brushes C&C are in contact with the removable positive and negative insulated
bridge piece B¹, B². These latter being connected to flexible wire to form a circuit
thro' glow lamps, a volt meter, or other such purpose.
For many of the switching arrangements shown different uses might be found, and
the positives & negatives may be reversed-my illustrations are intended to show one
definite purpose-The arrows shown the explanatory direction of the current.
The combinations already illustrated shew the manner in which (any successions or
combinations of switching operations that circumstances may require may be pre-
arranged on my principle so that mistakes in working are almost impossible even with
unskilled attendance.
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―
1. The use of clastic brushes for electrical switches, mounted in guides so as to be
easily adjustable and renewable substantially as described and shown, with the object
and for the purpose set forth.
2. The construction of the said brushes with their guiding holders or terminals
substantially as described and shown in figs. 17 to 23 with the object and for the
purpose set forth.
3. The arrangement and grouping of the said brushes to form a series of contacts
for multiple or compound switches, substantially as described and shown with the
object & for the purpose set forth.
4. The construction of electrical switches composed of the said brushes in com-
bination with movable or sliding bridge-pieces or their equivalents, substantially as
described and shown, with the object & for the purpose set forth.
5. The construction and arrangement of switches fitted with the said brushes in
combination with circular or polygonal bridge-pieces, substantially as described and
shown with the object & for the purpose set forth.
6. The construction and arrangement of switches fitted with the said brushes in
combination with a movable quadrant or sector, substantially as described and shown,
with the object and for the purpose set forth.
7. The construction of switches or their equivalents having the said brushes fitted
with removable bridge-pieces as in figs. 30 & 31, with the object and for the purpose
described.
S. The particular combinations shown on sheets 1, 2, 3, 4 and 5 substantially as
described.
9. The particular means shown and described of giving a quick cut off movement
to the various forms of switches-and the locking arrangements connected with
the same.
WILLIAM SNOWDON,
9, Beckett's Bank Chambers,
Leeds, Yorks.,
Agent for the Applicant.