Improvements in Switches for Altering the Speed and Direction of Revolution of Electric Motors.
Year: 1898

page_text: Date of Application, 17th Feb., 1898
Complete Specification Left, 17th Nov., 1898-Accepted, 17th Feb., 1899
PROVISIONAL SPECIFICATION.
PROVIDIUNAL DIECIFICATION.
Improvements in Switches for Altering the Speed and Direction of
Revolution of Electric Motors.
We, WILLIAM ROWLAND EDWARDS and SEPTIMUS FELIX BEEVOR, both of The
Thames Valley Launch Co., Ld., of Riverside Works, Weybridge, in the County of
Surrey, Electrical Engineers, do hereby declare the nature of this invention to be as
follows:-
Our invention relates more especially to electric motors used for propelling boats
or for other purposes, in which the current is supplied from electric storage or other
batteries, and in which it is required to drive the motor at different speeds and in
either direction, as, for instance, (in the case of a boat) at full speed or half speed
ahead, or at full speed or half speed astern, or to stop the motor altogether.
It has for its objects novel methods of construction and of connection of the
different parts, so that the different speeds and the direction of motion can be very
quickly and easily varied as desired, and the motor stopped and started, the apparatus
being simple, and easily applied, whilst injurious sparking of the parts by the contact
of which the several changes are effected can be avoided, and the apparatus is not
likely to get out of order.
In electromotors of the kind described, the speed of the motor is altered as required
by grouping the cells of the batteries in different ways. The direction of revolution
of the motor is altered by reversing the electrical connection of the conducting wire
round either the armature or the field magnet, but preferably the former.
Supposing, for example, that two speeds (half speed and full speed) in both direc-
tions are required, the arrangement and connections may be as follows:-
-
The battery is divided into two separate halves, which may be called B1 and B2,
the positive and negative terminals of B being called + 1 and 1 respectively, and
those of B being called + 2 and 2 respectively.
The brushes connected with the armature of the motor may be called A¹ and A2
respectively, the terminals of the coils surrounding the field magnet being called FI
and F2 respectively.
For the different purposes required, the various corresponding connections have to
be made, (by means of the switch), as follows :-

page_text: A2 to F2
The novel construction of the switch by which these different connections can be
rapidly and easily made as required, is as follows
Assuming that the switch board or case is viewed from above, a centre line passing
through the centres of the switches being parallel with the side nearest to the
observer, and the cover being removed ;-the centre upon which the switch arm
(which carries the brushes or equivalents by which the several contacts are made,) is
somewhat nearer the right hand of the board than the centre, and the several contact
pieces upon which the brushes upon the lower side of the switch arm press, are
arranged, with their connections, upon the lower board or base in the following
manner.
The several contact pieces are all curved concentric with the centre of the switch
arm, but at different distances from the centre, so as to form six semicircular
paths, each of which is not continuous but is formed as follows:-(it being under-
stood, in this description, that if a horizontal line be drawn from left to right
through the centre of the switch arm, the curved contact plates above this line are
those used for the connections to drive the motor ahead, and those below it are those
used for driving it astern).
The whole of the contact pieces are divided into two groups, those above the
centre-line occupying about one-third of the semicircle through which the switch
arın travels, those below the line also occupying about one-third, and the central
space between the two groups being left vacant, so that when the switch arm is placed
above this space, corresponding with the horizontal line just described, the motor is
at rest.
-
Taking the upper half first,-the first contact plate, adjoining or nearest the centre
upon which the switch arin turns, is in electrical connection with Fe (one terminal of
the field magnet coil). The next (second) curved concentric contact piece, at a
sufficient radial distance from the central one, occupies about one-third of the semi-
circle and is in electrical connection with A¹ (one of the armature brushes). The next
(third) contact piece also occupies the same angular space (one-third of the semi-
circle), and is in connection with A2 (the other armature brush). The next (fourth)
contact piece occupies a similar angular space, and is in connection with the
2 pole
of the second half, B2, of the battery. The next (fifth) outer contact piece has its
end adjoining the central vacant part of the semicircle in the same radial line as the
other contact pieces, but its other end extends to only about one-third of the cir-
cumferential length of the others. The next (sixth) outer contact piece has about
one-third removed at the centre, only its two ends remaining, and its inner or higher
end is in metallic connection with the fifth or adjoining inner contact piece last
described, both being in connection with the 1 pole of the first half, B¹, of the
battery. The outer (seventh) contact piece also has about one-third removed at its
-

page_text: centre, and its inner or higher end is in connection with the outer part of the sixth
or adjoining inner contact piece last described, both being in connection with the
+2 pole of the second half, B2, of the battery; and finally, the outer or right-hand
part of the seventh or outer contact piece is in connection with the + 1 pole of the
first half, B¹, of the battery.
The lower half of the semicircular set of contact pieces, or that relating to the
changes of current necessary for reversing the direction of revolution of the motor,
is similar to the upper one as far as regards the angular length and position of the
contact pieces, but the connections are different, as follows:-The second contact
piece is connected with the third on the outer or upper half, and therefore with the
armature brush A2. The third contact piece is connected with the second on the
other side, and therefore with the other armature brush A¹. The fourth is con-
2 pole of the B2 half of
nected with the fourth on the other side, and with the
the battery. The fifth contact piece is connected with the fifth on the other side,
1 pole of the B¹ half of the
and also with the inner end of the sixth, and with the
battery.
―
-
The outer end of the sixth contact piece is connected with the corresponding outer
end of the sixth on the other side, and also with the inner end of the outermost (or
seventh) contact piece, while both are connected with the + 2 pole of the B2 half of
the battery.
Finally, the outer end of the seventh contact piece is connected with the outer
end of the corresponding seventh contact piece on the other side, and also (in
the manner hereinafter described) with the F1 terminal of the field magnet
coils, so that both are connected with both this terminal F1 and the battery
pole +1.
The contact pieces or brushes on the lower side of the switch arm are three in
number, and of suitable length. They may be built up, or laminated, or solid, and
are so arranged that, as the arm is moved to its different positions, the brushes con-
nect the different contact pieces in the required way as described, the inner brush
always pressing upon the inner contact piece adjoining the central spindle of the
arm.
Of course the brushes are insulated from each other, and they are preferably
formed or provided with springs which press them into sufficiently good electrical
contact with the several contact pieces below them. As, however, "sparking" may
occur on the contact pieces when the brushes come in contact with, or leave, them,
we prefer to entirely cut off electrical current through them except when the brushes
are properly pressing upon the contact pieces. This we do by means of a separate
switch arm which works in proper relation with that already described, but which
gradually completes the circuit (between + 1 and F) when the switch brushes have
reached their proper position upon the contact pieces below, and gradually breaks the
circuit before the brushes have left the contact pieces.
For this purpose, we arrange on the left-hand side of the apparatus, viewed from
above as described, a second switch consisting of an arm turning upon a centre near
one of its ends, which end is provided with a brush or contact in metallic contact
with a curved contact plate below, which is connected with the terminal F1 of the
field magnet coil. The other or longer arm of this switch arm is also provided with
a brush or contact piece which presses in succession upon a series of separate fixed
contact pieces as the switch arm is moved through about a quarter of a circle.
When the switch arm described is in a central position (pointing, that is to say,
directly to the centre of the main switch arm first described), the contact or brush
upon its longer arm rests upon a central fixed contact piece which is in connection
with a conducting wire leading to and connected with the outer or seventh fixed
contact pieces of the apparatus first described, which contact pieces are therefore
connected, through the second switch arm (which forms an insulated conducting
bridge), with the terminal F¹ of the field magnet coil.
Assuming that a series of (say) three separate fixed contact pieces are used, against
which the longer arm of the second switch presses in succession as described, suitable
"resistances" of the well-known kinds are arranged between each, and between the

page_text: central one which is connected with F as described. If, therefore, the second switch
is in a position across the apparatus, with its longer arm resting upon the first of the
contact pieces, the current through the bridge has to pass through the whole of the
resistances, and as the switch is moved round, its longer arm passes in succession
over the other contact pieces, the resistance being gradually reduced until in its final
position the resistances have all been cut out and the current passes directly through
the bridge and through the contact under the shorter arm. The current is therefore
gradually (instead of suddenly), admitted to the circuit. A similar set of fixed
contact pieces and resistances (or the same resistances may be made use of) is
arranged on the opposite side of the apparatus, so that if the movement of the switch
arm or bridge is continued through another quarter of a circle the current is gradually
cut off from (instead of being gradually supplied to) the circuit.
During the other half of the revolution of the switch or bridge, (if it is turned
through a complete circle) its longer arın is free from any contact.
It only remains, therefore, to make an arrangement by which, whilst the current
is thus entirely cut off from the bridge-the other switch arm is adjusted into the
proper position (according to the requirements of full speed ahead, half speed ahead,
full speed astern, and half speed astern), and the continued movement of the second
switch or bridge then admits the current through the proper connections to obtain
the required result. In the same way, when a modified result is required, the
current is first gradually cut off, and the main switch is then moved into its
new position, and the current gradually re-admitted through the newly selected
eircuit.
In order to effect, this, we fix upon the spindle which carries the main switch a disc
of considerable diameter having a series of radial slots or noteles in its circumference,
and upon the spindle which carries the second switch or bridge we fix a second disc or
arm carrying a pin which engages with one or other of the slots, and (as the bridge
is turned round by a handle) at each complete revolution moves the larger disc and
main switch arm through a sufficient space to change the connections from one
position to the next.
The pin is so arranged that when it is acting upon one of the slots and turning the
main switch arm, the current through the bridge is cut off, whilst after the pin has
left the slot the continued revolution of the handle gradually admits the current
through the bridge and the main switch arm in the way already described. When
further alteration is required the handle is again turned, and the current is first
gradually cut off, and the pin then engages with one of the notches and brings the
inain switch into a fresh position, and after this is done the current is re-admitted.
Instead of the notched disc operated by a pin, equivalent devices may be made use
of. For instance, a toothed wheel may be fixed upon the spindle of the main switch
arm, gearing with a pinion upon the spindle of the conducting bridge. The pinion
is provided with teeth upon only a part of its circumference, so that it only causes
the revolution of the main switch arm at the time when the current has been cut off,
the remainder of the revolution of the handle leaving the larger toothed wheel
stationary, whilst the current is being gradually admitted or cut off.
A hand or pointer is carried by the spindle of the main switch arm, and shows the
exact position of the latter. By the use of suitable gear the necessary movements of
the second switch or bridge may be produced without a complete revolution of the
handle. A spring detent may be arranged, pressing against the notches in the disc,
or against other notches suitably arranged for the purpose, so that the position of
the main switch' arm is prevented from being accidentally altered, but without pre-
venting its revolution when required.
We preferably arrange a moveable contact plug in a suitable part of the conducting
wire circuit, which can be readily removed when desired, so as to prevent any
tampering with the apparatus.
We do not confine ourselves to the details of the apparatus, which may be varied
more or less as may be desired. For instance, the sets of contact pieces may be

page_text: arranged in complete circles, instead of semicircles, the movement of the handles
being through proportionately greater arcs.
The number of different effective positions of the main switch arm may be
increased to any desired extent, the necessary connections for the circuit of the
current being arranged accordingly.
Dated this 17th day of Walory 1809
EDWARDS and Co.,
65 and 66, Chancery Lane, London, Agents for the Applicants.
Improvements in Switches for Altering the Speed and Direction of
Revolution of Electric Motors.
We, WILLIAM ROWLAND EDWARDS and SEPTIMUS FELIX BEEVOR, both of The
Thames Valley Launch Co., Ld., of Riverside Works, Weybridge, in the County of
Surrey, 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 ascer-
tained in and by the following statement :-
Our invention relates more especially to electric motors used for propelling boats
or for other purposes, in which the current is supplied from electric storage or other
batteries, and in which it is required to drive the motor at different speeds and in
either direction, as, for instance, (in the case of a boat) at full speed or half speed
ahead, or at full speed or half speed astern, or to stop the motor altogether.
It has for its objects novel methods of construction and of connection of the
different parts, so that the different speeds and the direction of motion can be very
quickly and easily varied as desired, and the motor stopped and started, the apparatus
being simple, and easily applied, whilst injurious sparking of the parts by the contact
of which the several changes are effected can be avoided, and the apparatus is not
likely to get out of order.
The accompanying drawings are in illustration of our invention.
Figure 1 is a plan, partly in section, showing the several contact pieces and
connections;
Figure 2 is a transverse vertical section through the centre of the apparatus;
Figure 3 is an end view;
Figure 4 is a diagrammatic plan, illustrating the different contact-pieces, connections,
electro-motor, and batteries;
Figure 5 is a plan, and
Figure 6 a side view, shown partly broken off, of a modified method of operating
the switch.
Similar letters refer to similar parts throughout the several figures.
In electromotors of the kind described, the speed of the motor is altered as required
by grouping the cells of the batteries in different ways. The direction of revolution
of the motor is altered by reversing the electrical connection of the conducting wire
round either the armature or the field magnet, but preferably the former.
Supposing, for example, that two speeds (half speed and full speed) in both
directions are required, the arrangement and connections may be as follows-as
illustrated in diagram in Figure 4 :-
The battery is divided into two separate halves, which may be called B and B²,
the positive and negative terminals of B¹ being called ÷ 1 and 1 respectively, and
those of B2 being called ÷ 2 and 2 respectively.
The brushes connected with the armature of the motor M may be called A¹ and A²

page_text: respectively, the terminals of the coils surrounding the field magnet N being
called F1 and F2 respectively.
For the different purposes required, the various corresponding connections have to
be made (by means of the switch), as follows:-
For full speed astern :-
-
1 to 2
-
2 to A¹
A² to F2
F1 to 1.
For half speed astern :--
1 and F¹, to ÷ 2
2 and 1, to A¹
A
to F2.
The novel construction of the switch by which these different connections can be
rapidly and easily made as required is as follows:-
Assuming that the switch board or case is viewed from above as shown in Figure 1,
a centre line x-y passing through the centre of the switches being parallel with the
side nearest to the observer, and the cover a being removed;-the centre or spindle
upon which the switch arm b (which carries by screws H the brushes or
equivalents c, c, c, by which the several contacts are made), is shown at d, somewhat
nearer the right hand of the board than the centre, and the several contact
pieces e¹,... e³, & e¹x. . . . ex, upon which the brushes c upon the lower side of the
switch arm 6 press, are arranged, with their connections, upon the lower board or
base g in the following manner.
The several contact pieces el, e², . e7, and elx, e2x. ex, are all curved concentric
with the centre d of the switch arm, but at different distances from the centre, so as
to form six semicircular paths, each of which is not continuous but is formed as
follows: (it being understood, in this description, that the curved contact plates
above the line x-y in the drawing are those used for the connections to drive the
motor ahead, and those below it are those used for driving it astern).
The whole of the contact pieces e are divided into two groups, those above
the centre line -y occupying about one-third of the semicircle through which the
switch-arm b travels, those below the line also occupying about one-third, and the
central space between the two groups being left vacant, so that when the switch
arm is placed (as shown at 61, in Figure 1). above this space, corresponding with
the horizontal line x-y, the motor is at rest.
Taking the upper half first,-the first contact plate e adjoining or nearest to the
centre upon which the switch arm turns, is in electrical connection with F2 (one
terminal of the field magnet coil, Figure 4). The next (second) curved concentric

page_text: contact piece e2, at a sufficient radial distance from the central one, occupies about
one-third of the semi-circle, and is in electrical connection, through the conductor k²
and the lower contact piece ex, with A¹ (one of the armature brushes, see Figure 4).
The next (third) contact piece e also occupies the same angular space (one-third of
the semi-circle), and is in connection with the terminal h¹, Figure 1, and through it
with A2, (the other armature brush, see Figure 4). The next (fourth) contact piece e*
occupies a similar angular space, and is in connection, directly, or through the
conductor, with the -2 pole of the second half, B2, of the battery (see Figure 4).
The next (fifth) outer contact piece e5 has its end adjoining the central vacant part
of the semicircle in the same radial line as the other contact pieces, but its other end
extends to only about one-third of the circumferential length of the others. The
next (sixth) outer contact piece e has about one-third removed at the centre, only
its two ends remaining, and its higher end (or that nearest the top of the drawing) is
in metallic connection, through the conductor with the fifth or adjoining inner
contact piece e last described, both being in connection, through the conductors
and 6, and the terminal 3,(Figure 1) with the 1 pole of the first half, B',of the battery
(Figure 4). The outer (seventh) contact piece e also has about one-third removed
at its centre, and its inner or higher end is in connection, through the conductor 10,
with the outer part of the sixth or adjoining inner contact piece e last described, both
being in connection, through the terminal ht, with the 2 pole of the second half, B2,
of the battery (Figure 4); and finally, the outer or right-hand part of the seventh
or outer contact piece e is in connection, through the terminal, with the +1 pole
of the first half, B', of the battery (Figure 4). It will be understood that the
concentric segments shown in Figure 4, and the shaded segments in Figure 1
represent the conducting contact pieces over which the brushes of the switch
pass to make contact, and the parts between them are of non-conducting material
over which the brushes (c, Figures 2 and 3) pass between the contact pieces.
The metallic connections between the different conducting seginents e are shown
in dotted lines in Figures 1 and 4. They are arranged below the base g of
the instruments, as seen in Figures 2 and 3.
-
The lower half of the semicircular set of contact pieces, or that relating to the
changes of current necessary for reversing the direction of revolution of the motor,
is similar to the upper one as far as regards the angular length and position of the
contact pieces, but the connections are different, as follows:-The second contact
piece ex is connected, through the conductor with the third on the upper half,
The third
and therefore, through the terminal h¹, with the armature brush A².
contact piece ex is connected through the conductor with the second, e, on the
other side, and, through the terminal h, with the other armature brush A¹. The
fourth, ex, is connected, by the conductor 4, with the fourth et on the other side,
and, through the terminal 2, with the -2 pole of the B half of the battery,
(Figure 4). The fifth contact piece ex, is connected, by the conductor, with the
fifth, e on the other side, and also, through the conductor, with the inner end of
the sixth, ex, and, through the terminal ³, with the 1 pole of the B1 half of the
battery.
The outer or right-hand end of the sixth contact piece ex is connected, throngb
the conductor 8, with the corresponding outer end of the sixth, e", on the other side,
and also, through the conductor, with the inner end of the outermost (or seventh)
contact piece ex, while both are connected, through the conductor 10 and the
terminal, with the 2 pole of the B2 half of the battery.
Finally, the outer end of the seventh contact piece ex is connected, through the
conductor 2, with the outer end of the corresponding seventh contact piece e7 on
the other side, and also, through the conducting wire (in the manner hereinafter
described) with the terminal to the terminal of the field magnet coils, so that
both contact pieces e and ex are connected with both this field magnet terminal F,
and, through the terminal h", with the battery pole ÷ 1.
The contact pieces or brushes c¹, c², c³, c², c³, c, on the lower side of the switch
arm bare six in number, and of suitable length. The inner one c¹ presses upon the

page_text: contact pieces e² and e²x, as the switch b is turned. It is also in constant connection
with the inner contact ring e¹, through the metal arm b. The brushes c², c³, c, press upon
the contact pieces e³, ex, et, ex, and e, ex, respectively, as the switch is turned. They
are in metallic connection with each other, but are insulated, by insulating material o
from the switch arın band the other brushes. The brushes e and c press upon the
contact pieces e", ex, and e7, ex, respectively. They are in metallic connection with
each other, but are also insulated from the switch arm b and the other brushes.
In this way, as the arm is moved to its different positions, the brushes connect the
different contact pieces in the required way as already described, the inner brush
being always in metallic connection with the inner contact piece el adjoining the
central spindle of the arm b. The brushes c may be solid or built-up, or
"laminated," and fit into recesses in metal blocks p, p, insulated from but attached
to the switch arm b, and they are formed or provided with springs which press
them into sufficiently good electrical contact with the several contact pieces e below
them.
**
As, however, sparking" may occur on the contact pieces when the brushes come
in contact with, or leave them, we prefer to entirely cut off electrical current through
them except when the brushes are properly pressing upon the contact pieces. This
we do by means of a separate metal switch m, which works in proper relation with
that already described, but which gradually completes the circuit (between ÷1
and F) when the switch brushes c have reached their proper position upon the contact
pieces e below, and gradually breaks the circuit before the brushes have left the
contact pieces.
For this purpose, we arrange on the left-hand side of the apparatus, viewed from
above as described, a second switch consisting of an arm m turning upon (but
insulated from) a centre n near one of its ends, which end is provided with a brush
or contact piece s in metallic contact with a curved contact plate t below, which is
connected with the terminal F1 of the field magnet coil, (see Figure 4). The other
or longer arm of this switch arm m is also provided with a brush or contact
piece which presses in succession upon a series of separate fixed contact
pieces 1, 2, 3, as the switch arm m is moved through about a quarter of a
circle.
When the switch arm described is in a central position (pointing, that is to say,
directly to the centred of the main switch arm first described), the contact or brush v
upon its longer armrests upon a central fixed contact piece which is in connection
with a conducting wire leading to and connected with the outer or seventh fixed
contact pieces e (and ex to which it is connected) of the apparatus first described, (see
Figure 4), which contact pieces are, therefore, connected, through the second
switch arm (which forms an insulated conducting bridge), with the terminal F¹ of
the field magnet coil.
*
Assuming that a series of (say) three separate fixed contact pieces w¹, w², 20³,
shown, are used, against which the brush upon the longer arm 26 of
the second switch presses in succession as described, suitable "resistances" y¹, y², y³,
of the well-known kinds are arranged between w¹ and w², w² and w, and
between 3 and the central one which is connected with 1 of the field
magnet as described. If, therefore, the second switch m is in a position across
the apparatus, with the brush on its longer arm resting upon the first 21 of the
contact pieces, the current through the bridge has to pass through the whole of the
resistances y', y², y³, on its way to x, and as the switch m is moved round, its longer
arm u passes in succession over the other contact pieces 2 and 3, the resistance
being gradually reduced until in its final position the resistances have all been cut
out and the current passes through a, directly through the bridge, and through the
contact t under the shorter arm. The current is therefore gradually (instead of sud-
denly), admitted to the circuit. A similar set of fixed contact pieces wx, 202x,
and x, and resistances y¹x, y2x, and y³, (or the same resistances may be made use
of) is arranged on the opposite side of the apparatus, so that if the movement of the

page_text: switch arni or bridge m is continued through another quarter of a circle the current is
gradually cut off from (instead of being gradually supplied to) the circuit.
During the other half of the revolution of the switch or bridge (over the part
marked, Figure 1), (if it is turned through a complete circle) its longer arm is free
from any contact.
It only remains, therefore, to make an arrangement by which,-during the time
that the current is thus entirely cut off from the bridge m- -the other switch arm b
is adjusted into the proper position (according to the requirements of full speed ahead,
half speed ahead, full speed astern, and half speed astern), and when this has been
done the continued movement of the second switch or bridge m then admits the
current through the proper connections to obtain the required result.
In the same
way, when a modified result is required, the current is first gradually cut off, and the
main switch is then moved into its new position, and the current gradually re-admitted
through the newly selected circuit.
In order to effect this, we fix upon the spindle & which carries the main switch (as
shown in Figures 2 and 3, and in Figure 5) a disc 1 of considerable diameter,
insulated from the spindle d, and having a series of radial slots or notches 2, 3, 4, and 5,
in its circumference, and upon the spindle which carries the second switch
or bridge m we fix a second disc or arm 6 carrying a pin 7 which engages with
one or other of the slots 2, 3, 4, and 5, and (as the bridge m is turned round by a
handle 8) at each complete revolution moves the larger disc I and main switch
arm through a sufficient space to change the connections from oue position to
the next.
The pin 7 is so arranged that when it is acting upon one of the slots and turning
the main switch arm b, the current through the bridge m is cut off, whilst after the
pin 7 has left the slot the continued revolution of the handle 8 gradually admits the
current through the bridge and the main switch arm b in the way already described.
When further alteration is required the handle 8 is again turned, and the current is
first gradually cut off, and the pin 7 then engages with one of the notches and
brings the main switch b into a fresh position, and after this is done the current is
automatically re-admitted.
Instead of the notched disc operated by a pin, well-known equivalent devices
may be made use of. For instance, a toothed wheel may be fixed upon the
spindle of the main switch arm, gearing with a pinion upon the spindle of the
conducting bridge. The pinion is provided with teeth upon only a part of its
circumference, so that it only causes the revolution of the main switch arm at the
time when the current has been cut off, the remainder of the revolution of the handle
leaving the larger toothed wheel stationary, whilst the current is being gradually
admitted or cut off.
A handle or pointer 9 is carried by the spindle d of the main switch arm b, and
shows the exact position of the latter. By the use of suitable gear the necessary
movements of the second switch or bridge may be produced without a complete
revolution of the handle. For this purpose the arrangement illustrated in Figures 5
and may be used. The handle 8 is carried upon a third spindle 10, which has
fixed upon it a toothed wheel 11, gearing with a smaller pinion 12 upon the spindle n,
of the smaller switch. By this means the requisite number of revolutions of the
wheel 6, and pin 7, to move the main switch through the required number of degrees
of a circle, can be effected by a single revolution, or by part of a revolution, of the
handle 8.
A spring detent may be arranged, pressing against the notches in the disc, or
against other notches suitably arranged for the purpose, so that the position of the
main switch arm is prevented from being accidentally altered, but without preventing
its revolution when required. This arrangement, which is not essential, is so obvious
that it has not been illustrated.
We arrange a moveable contact plug in a suitable part of the conducting wire
circuit (for instance at 13, Figures 1 and 4), which can be readily removed when
desired, so as to prevent any tampering with the apparatus.

page_text: The number of different effective positions of the main switch arm may be increased
to any desired extent, the necessary connections for the corresponding circuits of the
current being arranged accordingly.
The insulated cases containing the spring brushes can be readily removed when
necessary, to substitute fresh brushes.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what we
claim is
1.The combination, in a switch for altering the speed and direction of revolution
of electric motors, of a spindle & turning in bearings in the frame a, g, switch arm b,
carrying spring brushes c², c², c³, c, c, c, insulated from the switch arm b, concentric
insulated contact pieces e¹, e², c³, et, e³, e, e7, below the spring brushes c, on the side
of the central line x-y, concentric insulated contact pieces ex, ex, eix, eix, ex, e7x,
below the spring brushes c, but on the other side of the central line x--y, insulated
conductors, k³, k³, k³, ko, k³, 19, 10, 11, 12, connecting the different concentric
contact pieces e¹
ex, and conducting wires and terminals h, h¹,
h2, h3, h, and 6, with the poles ÷ 1,
2,2 and 2 of the two halves of the
batteries B1, B2, with the coils of the field magnets at F1, F2, and with the commutator
brushes A1, A2, substantially as described.
e³,
e2x
-
spring
e7x,
hº, of
2. The combination with the spindle d, switch arm b, insulated
brushes c¹ co, concentric insulated contact pieces e¹
e', and ex
insulated conductors
, and conducting wires and terminals h.
the handle 8 on the second spindle n carrying insulated bridge m, spring brushes s
and v, insulated concentric contact pieces t, w¹, w³, w³, x, w1x, w²x, w³, resistances y¹,
y², y³, y¹, y**, y3x, conductor & between the contact pieces x and ex, and conductor
from the contact piece t to the terminal and terminal F of the field magnet coil,
substantially as described.
3. In a switch for altering the speed and direction of revolution of electric motors,
in combination with the spindle d which carries the switch arm p by which the
distribution of the electric current is effected, and the spindle n which carries the
switch arm m and the handle 8 by which the electric current is switched "on" and
"off," the dise fixed upon the spindle d and having at its circumference notches 2,
3, 4 and 5, into one or other of which notches a pin 7 upon a disc or arm 6 fixed upon
the spindle n engages, so that at every complete revolution of the handle 8 the pin 7
turns the disc 1 partly round at the time when the current through the switch mis
"off," the disc I being free to revolve when the pin 7 is not engaged with one of the
notches, substantially as described.
4. In a switch for altering the speed and direction of revolution of electric motors,
the combination of the spindle d which carries the switch arm by which the distribution
of the electric current is effected, and the spindle n which carries the switch arm m
by which the electric current is switched "on" and "off," and the disc 1 fixed upon
the spindle and having at its circumference notches 2, 3, 4 and 5 into one or other of
which notches a pin 7 upon a disc or arm 6 fixed upon the spindle n engages, so that
at every complete revolution of the spindle n the pin 7 turns the disc partly round at
the time when the current through the switch m is "off," the disc 1 being free to
revolve when the pin 7 is not engaged with one of the notches, and the third
spindle 10, carrying the handle 8 and having fixed upon it, a toothed wheel 11,
gearing with a smaller toothed pinion 12 fixed upon the spindle n, substantially as
described.
Bated Cins 17th day of November, love.
EDWARDS AND CO.,
Chartered Patent Agents, 65 and 66, Chancery Lane, London,
Agents for the Applicants.