provements in Controlling Apparatus for Electric Lifts and other Electric Machines.
Year: 1899

page_text: Date of Application, 11th Dec., 1899
Complete Specification Left, 25th Aug., 1900-Accepted, 24th Nov., 1900
PROVISIONAL SPECIFICATION
Improvements in Controlling Apparatus for Electric Lifts and other
Electric Machines.
JOHN SANDERS STEVENS, CHARLES GEORGE MAJOR, EDWIN CHARLES STEVENS,
& PERCY HERBERT STEVENS, Engineers, of Janus Works, Queens Road,
Battersea, in the County of London, do hereby declare the nature of this inven-
tion to be as follows:-
Our invention has reference primarily to direct coupled electric lifts, work-
ing with continuous current, & has for its objects an improved method of con-
trolling the starting resistances, and an improved construction of starting &
reversing switches.
Our method of working combines the following conditions:-
(1) The act of stopping the machine inserts the whole resistance ready for
the next start.
(2) Once the resistances are inserted they cannot be withdrawn except by
the actual starting & continued running of the motor.
(3) The rate of automatic withdrawal may be as slow as may be desired.
(4) The resistances may be reinserted by the operator, either rapidly or
gradually at his discretion; in the latter case acting as a speed controller.
(5) The armature circuit is opened or closed by the reversing switch simul-
taneously at a considerable number of points arranged in series.
We effect our objects thus:-Taking the case of a lift actuated by a winding
drum coupled to the motor by any form of gearing, we fix on the winding
drum shaft a small wheel or cam with waved periphery, giving an oscillatory
motion to one end of a lever. To any convenient part of this lever we attach
a link to work a ratchet feed wheel always turning in the same direction; the
ratchet wheel is connected with the switch arm of the rheostat by any form of
frictional coupling, adjusted to grip sufficiently to work the switch, but free to
slip on encountering a greater resistance; the motion of the switch we usually
limit to an angle not exceeding 90 degrees.
Assume that the resistances have been inserted, the switch arm being at the
topmost limit of its travel, & that the motor is started in either direction. The
wave wheel will then, irrespective of its direction of revolution, give motion to the
ratchet wheel, & through the medium of the friction coupling to the switch
arm of the rheostat, till the requisite movement has been obtained to cut out the
resistance, when the switch arm coming into contact with a projecting stop is
held in the required position, while the continued motion of the lift only causes
the friction coupling to slip.
It will be noted in passing that by varying the proportions of the parts the
time of cutting out the resistances may be made to correspond accurately to
any desired number of revolutions of the motor.
It will also be noted that by adding one or two contact points to the rheostat
switch, the series coils of a compound wound motor may also be cut out auto-

page_text: :
matically immediately after the resistances; but this forms no part of our
invention.
When it is desired to reinsert the series coils & the resistances, (or the resist-
ances only as the case may be) preparatory to stopping the machine, the neces-
sary motion is derived from the starting apparatus which actuates the reversing
switch & brake. Should this apparatus be of the revolving or oscillating shaft
& drum type, we fit a double acting cam on this shaft, formed to impart to a
lever connected to it, one & the same motion, whether the shaft be turned to
the right or to the left; that is to say whether the lift be started up or down.
This lever gives a simple pushing motion to the rheostat lever, but has no
power to pull it.
When the ratchet wheel motion already described has carried the rheostat
lever forward till it is in contact with its stop, this lever is also in contact with
the cam lever, & if now the reversing shaft is turned by the operator into the
centre position for stopping the machine, the cam lever "pushes the rheostat
lever back to the original full resistance position, this backward movement
being rendered possible by the slipping coupling.
But we so design & time the motions of the controlling gear, that the whole,
or nearly the whole of the resistance is reinserted before the brake is put on,
or the main reversing switch opened. Under these conditions a partial move-
ment of the reversing shaft will insert a portion only more or less of the resist-
ance, & the speed of the motor can thus be gradually reduced, rendering the
final stop less abrupt & unpleasant than when all resistances are inserted at
once, or when they are rendered inoperative by the simultaneous reversal of
the rheostat switch, & opening of the starting switch, in which case the stop
has to be made from full speed entirely on the brake.
On restarting the machine in either direction, the cam on reversing shaft
will carry its lever clear out of the way of the rheostat lever, leaving the latter
behind, with a sufficient clear path within which to make its gradual return; &
should the operator fail to pull the reversing gear entirely over, & thus allow
the cam lever to stand prematurely in the way of the rheostat lever, cutting
short the course of the latter, the only effect will be a slower motion of the lift,
which will at once indicate the fault to the operator.
In the form of slipping coupling we prefer to employ, a small spring presses
altogether, the ratchet wheel, a disc of leather or other yielding material, &
a metal disc attached to the rheostat switch arm, & thus the ratchet wheel
drives the switch arm by frictional contact. When the switch arm has com-
pleted its travel, the ratchet wheel slips on the leather disc during the remainder
of the journey of the lift. The contact surfaces are mounted upon a backing of
slate.
We sometimes employ a different method of imparting the slow cutting out
motion to the rheostat switch arm, the reinserting devices remaining as already
described. We then mount upon the winding drum shaft, in place of the wave
wheel, a pair of similar toothed pinions running loosely on the shaft. & driven
only by frictional contact in any known manner: as for instance by placing
a leather disc between each pinion & a driving disc keyed on to the shaft, all
being held in contact by spring pressure. Each pinion gears into a rack, one
rack being placed on the right of one pinion, while the other rack is placed
on the left of the second pinion, & the racks are therefore driven in opposite
directions. Each rack is continued in the form of a connecting link, & both
are coupled to a lever fixed to, or forming part of, the rheostat arm. The
actual connection is in the form of a longitudinal slot in the end of the rack
link, sliding on a pin in the lever end, so that the links can pull the lever but
cannot push it.
The action is as follows:-When the drum shaft commences to revolve in
either direction, the two racks commence to travel in opposite directions; the
one which travels toward the rheostat arm is idle by reason of its slot; the other

page_text: ance.
rack travelling away pulls the rheostat arm with it, & thus cuts out the resisi-
When this is completed the link comes into contact with a stop preventing
farther movement, & the pinion thenceforward slips on the friction driver
during the farther travel of the lift. The action of stopping the machine
replaces the rheostat arm in the original position in the manner previously
described, & in doing so pulls back the rack which had last been actuating it,
the slipping pinion rendering this possible. If the lift is to be restarted in
the same direction as before the same actuating rack is now in position for
repeating its duty; while if the opposite direction given to the lift, the other
rack is in position to take up the pulling motion.
In some cases the rheostat arm is required to move through a greater angle
than 90°. We then employ another device for returning it to the starting
position. The arm has attached to its centre a pinion embraced by a looped
toothed rack, secured to one end of the returning cam lever. The cam in this
Assume as before that all
case gives downward motion only to the lever.
resistance is in & the motor standing. To start in either direction the returning
cam is turned out of the way of its own lever, & the course is then clear for
the pinion to revolve, giving motion to the looped rack linked to the cam lever,
which is stopped at the desired point by again coming into contact with its
cam. The resistances are now all out, & thenceforward the coupling slips as
before. To reinsert resistances, the returning cam is again placed in the reverse
position. With this device a complete circle may be described by the rheostat
arm if desired.
In some cases it might be objectionable to cut out the resistances with the
We then duplicate the actuating
intermittent motion of a simple ratchet.
wave wheel on the winding drum shaft, its lever, & accompanying ratchet
wheel, & by arranging the wave wheel prominences to alternate we obtain a
continuous motion of the rheostat arm.
In cases where there is no drum shaft in the controlling or reversing gear,
there will certainly be some oscillating lever gear to which a mechanical equiva-
lent of the double acting returning cam can be attached, by which the same
reinserting movement may be produced.
Still considering the case of winding drum machines, we find it convenient
in some instances to mount the wave wheel or cam on an independent spindle
of its own, receiving motion from any revolving portion of the machine by
means of spur or worm gearing, pitch chains or belts; in the latter case the
belt may be adjusted to slip & the slipping coupling dispensed with.
In some cases we dispense with the wave wheel & use in its place a crank
pin, or eccentric with connecting rod to reciprocate the ratchet.
In the case of screw machines the wave wheel or its equivalent is attached
to any of the non-travelling rope wheels; or we dispense with it entirely, &
ause a waved rack or rod of the same length & travel as the screw;
other cases we drive the wave wheel by means of an endless band or chain,
attached to the travelling crosshead on the screw.
or in
In some cases we avoid the use of slipping coupling in the following manner.
Instead of using a complete ratchet wheel with continuous motion, we employ
a toothed arc of a wheel, or a straight rack, the toothed length being only that
necessary to give the requisite movement to the switch. Beyond the last tooth
the surface of the rack rises in a short inclined plane up which the tip of the
pawl slides on arriving at that point. The pawl is in this case provided with
a pivotted bob in unstable equilibrium, so that the sliding of the point up the
incline tips the bob over & out of gear, & once in this position the switch &
rack attached may be pushed back for slowing speed, "while the pawl siill
reciprocates clear of it. But the ratchet rack carries at the other end a reverse
incline which when brought back to the stopping or full resistance position,
trips the pawl bob the other way, throws it again into gear, & immediately
the machine restarts, the pawl again proceeds to work the rack over & cut out

page_text: resistance. The reciprocation of the pawl & reinsertion of resistance are pro-
duced in the manner previously described.
We carry out that portion of our invention relating to the reversing switch
in the following manner. We arrange along a slate or other insulating founda-
tion four parallel rows of contact pieces, each row having any desired number
of contacts not less than four. For illustration we assume each row consists
of six. Let the rows be distinguished by letters a, b, c, & d; & the contact
pieces by numbers 1 to 6 in each row; the individual contacts may then be
designated a, b, d, etc. In each row the distances between contacts 1 & 2,
3 & 4, 4 & 5, 5 & 6 are all equal; but the distance between 2 & 3 in each row
is one half greater. The distance from row to row is immaterial except for con-
siderations of insulation. Contacts a¹, a², & a³, are electrically connected; a
& as are also coupled. Contact, is connected to the main; b² to
the+main; 63 & 6 are coupled; 65 & 66 are coupled, & 66 is also connected
to one of the motor brushes. Contact c¹ is connected with the + main;
² to the main; & are coupled; & care coupled, & 6 is also
connected with the opposite brush of motor. Contacts in row d are coupled
exactly as in row a.
-
A metal bar sliding endwise in suitable guides, lies along the centre between
rows & parallel with them, & a similar bar lies between rows c & d. These
bars are rigidly coupled together so as to move simultaneously. Each bar
carries five insulated bridges, placed in such positions that they will as regards
the first bar connect a² to 63, a³ to b³, a to b, a³ to b³, & a to 66; & as regards
the second bar connect to, c³ to d³, c to d, to d³, & 6 to do. Under these
conditions the circuit is from + main through 6², a², a³, b³, b, as, a³, 65, 66, to first
commutator brush, through armature to second brush, thence through 6, 5, d³,
d', c, c, d, d³, c²; & thence to - main. Contacts a & d are idle being merely
supports for the ends of the last bridges when in this position. Contacts a¹, b¹,
c¹, & dare also idle in this position.
If now the pair of sliding bars are moved endwise sufficiently to break contact
between the various bridges & the contact plates, the circuit will have been
broken simultaneously at nine points along each main, or eighteen in all.
Farther, assuming that the bridges have moved away from pairs of contacts
on their left, & that the motion is continued they will reclose the circuit by
making contact between the pairs of contacts on their right; & the
direction of the circuit will now be reversed, for it enters from + main
at c', passes through d', d², d³, c³, c², d², d³, c³, c to what was previously the
brush, but 18 now the +,
through motor to opposite brush,
to 66, 65, a, a, 64, b³, a³, a², a¹, b¹, & thence to minus main.
In this circuit, contacts a, 2, c², & 66 are idle, as are the two bridges lying
between the four No. 2 contacts, & the four No. 3 contacts.
When this circuit is opened, it is broken at eight points in each main, or
sixteen in all. It is obvious that the system may be extended indefinitely, the
addition of a pair of contacts and one bridge on one line adding two extra
breaks, with a similar result from a similar addition on the other line. Con-
versely the system may be reduced by the omission of similar sets, till the
minimum complete system is reached. This consists of rows of four plates each,
with three bridges in each line.
In cases where this elementary system is found sufficient, we simplify the
arrangement in the following manner, premising that this modification does
not lend itself so well to indefinite extension as does the system first described.
The contact plates are arranged in four rows, which may still be designated a,
b, c, & d, each row having four plates numbered 1 to 4. All the plates in row a
are connected together. Plate 61 is connected with the main; with the
main; 3 & 4 are coupled, & 64 is connected with one commutator brush.
Plate is connected with the main with the + main; & care coupled.
& c is connected with the other commutator brush. Plates in row d are all
-

page_text: coupled together. A sliding bar for carrying bridges lies as before between
rows a &, & another bar between rows c & d; each bar carries two bridges.
In the position first to be considered, the bridges will couple a¹ & a³ respectively
to b&b, & also ¹. & respectively to d¹ & B.
The circuit thus made will be from + main through b', across bridge to a¹,
thence to a², & a³, by bridge to 63, & 4, through armature to c & ³, by bridge
main terminal,
to d, thence to d² & d', by bridge to which is
-
If now the bridges be moved so that they lie midway between plates 1 & 2 &
between 3 & 4, the circuit will have been broken at eight points simultaneously.
If the bridges be moved still farther so that they lie on all the plates numbered
2 & the circuit will be reclosed, but in the opposite direction; for it now
enters from main at 2, & proceeds by d³, 3, &, through armature to b',
& on by a, a³, a², & 62 to
A return of the bridges to the mean position,
opens this circuit also at eight points simultaneously.
In this arrangement four coupling bridges suffice instead of six..
-
main.
Improvements in Controlling Apparatus for Electric Lifts and other
Electric Machines.
JOHN SANDERS STEVENS, CHARLES GEORGE MAJOR, EDWIN CHARLES STEVENS,
& PERCY HERBERT STEVENS, Engineers, of Janus Works, Queens Road,
Battersea, S.W., in the County of London, 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:-
Our invention has reference primarily to direct coupled electric lifts, work-
ing with continuous current, & has for its objects an improved method of con-
trolling the starting resistances, and an improved construction of starting &
reversing switches.
Our method of working combines the following conditions:-
(1). The act of stopping the machine inserts the whole resistance ready for
the next start.
(2). Once the resistances are inserted they cannot be withdrawn except by
the actual starting & continued running of the motor.
(3). The rate of automatic withdrawal may be as slow as may be desired.
(4). The resistances may be re-inserted by the operator, either rapidly or
gradually at his discretion; in the latter case acting as a speed controller.
(5). The armature circuit is opened or closed by the reversing switch simul-
taneously at a considerable number of points arranged in series.
In the following description, the same reference letters apply to similar or
equivalent parts in all the figures.
We effect our objects thus:--Taking the case of a lift actuated by a winding
drum coupled to the motor by any form of gearing, we fix on the winding
drum shaft A Fig. 1 a small wheel or cam B, with waved periphery, giving an.
oscillatory motion to one end of a lever, C. To any convenient part of this
lever we attach a link D to work a ratchet feed wheel E always turning in the
same direction; the ratchet wheel E is connected with the switch arm F of

page_text: the rheostat G by any form of frictional coupling H, adjusted to grip sufficiently
to work the switch, but free to slip on encountering a greater resistance; the
motion of the switch we usually limit to an angle not exceeding 90 degrees.
Assume that the resistances have been inserted, the switch arm being at the
topmost limit of its travel as in Fig. 1, and that the motor is started in either
direction. The wave wheel B will then, irrespective of its direction of revolu-
tion, give motion to the ratchet wheel E, & through the medium of the friction
coupling H to the switch arm F of the rheostat, till the requisite movement
has been obtained to cut out the resistance, when the switch arm coming into
contact with a projecting stop I is held in the required position, while the
continued motion of the lift only causes the friction coupling H to slip.
It will be noted in passing that by varying the proportions of the parts the
time of cutting out the resistances may be made to correspond accurately to
any desired number of revolutions of the motor.
It will also be noted that by adding one or two contact points to the rheostat
switch, the series coils of a compound wound motor may also be cut out auto-
matically immediately after the resistances; but this forms no part of our
invention.
When it is desired to re-insert the series coils. & the resistances, (or the resist-
ances only as the case may be) preparatory to stopping the machine, the neces-
sary motion is derived from the starting apparatus which actuates the reversing
switch & brake. Should this apparatus be of the revolving or oscillating shaft
& drum type, we fit a double acting cam J on this shaft K, formed to impart
to a lever L connected to it, one and the same motion, whether the shaft be
turned to the right or to the left; that is to say whether the lift be started
up or down. This lever L gives a simple pushing motion to the rheostat
lever F, but has no power to pull it.
When the ratchet wheel motion already described has carried the rheostat
lever F forward till it is in contact with its stop I, this lever is also in contact
with the cam lever L, and if now the reversing shaft K is turned by the operator
into the centre or midway position for stopping the machine, the cam lever L
pushes the rheostat lever back to the original full resistance position as in
Fig. 2, this backward movement being rendered possible by the slipping
coupling H.
But we so design & time the motions of the controlling gear, that a large
proportion of the resistance is re-inserted before the brake is put on, or the main
reversing switch opened. Under these conditions a partial movement of the
reversing shaft K will insert a portion only more or less of the resistance, and
the speed of the motor can thus be gradually reduced rendering the final stop
less abrupt & unpleasant than when all resistances are inserted at once, or when
they are rendered inoperative by the simultaneous reversal of the rheostat
switch, & opening of the starting switch, in which case the stop has to be made
from full speed entirely on the brake.
On restarting the machine in either direction, the cam J on reversing shaft
will carry its lever L clear out of the way of the rheostat lever F, leaving the
latter behind as in Fig. 1, with a sufficient clear path within which to make
its gradual return; and should the operator fail to pull the reversing gear
entirely over, & thus allow the cam lever L to stand prematurely in the way
of the rheostat lever F, cutting short the course of the latter, the only effect
will be a slower motion of the lift, which will at once indicate the fault to the
operator.
In the form of slipping coupling we prefer to employ, a small spring M Fig. 3
presses altogether, the following parts viz. the ratchet wheel E, a disc of leather
or other yielding material N, and a metal disc H attached to the rheostat switch
arm F, and thus the ratchet wheel E drives the switch arm F by frictional
contact. When the switch arm F has completed its travel, the ratchet wheel E
slips on the leather dise N during the remainder of the journey of the lift.

page_text: The contact surfaces are mounted upon a backing of slate, or other insulating
material P.
We sometimes employ a different method of imparting the slow cutting out
motion to the rheostat switch arm, the re-inserting devices remaining as already
described. We then mount upon the winding drum shaft A Figs. 4, 5, & 6,
in place of the wave wheel, a pair of similar toothed pinions QQ¹ running
loosely on the shaft A, & driven only by frictional contact in any known
manner; as for instance by placing a leather disc N N between each pinion and
a driving disc R keyed by loose feathers on to the shaft A, all being held in
contact by the pressure of spring T. Each pinion Q Q¹ gears into a rack U U!,
one rack being placed on the right of one pinion Fig. 5, while the other rack
is placed on the left of the second pinion Fig. 4, and the racks are therefore
driven in opposite directions. Each rack is continued in the form of a connect-
ing link, & both are coupled to a lever V fixed to, or forming part of, the
rheostat arm F. The actual connection is in the form of a longitudinal slot W
in the end of the rack link, sliding on a pin in the end of lever V, so that the
rack links can pull the lever V but cannot push it. Fig. 4 shews one of these
pinions & racks, and Fig. 5 the other. Fig. 6 shews the pinions and driving
disc mounted on the driving shaft.
The action is as follows:-When the drum shaft A commences to revolve in
either direction, the two racks U U endeavour to travel in opposite directions ;
but the pinion of the one which should move downwards in the fig. slips and
is idle; while the other rack travelling upwards pulls the rheostat arm VF
with it, & thus cuts out the resistance. When this is completed the rack comes
into contact with a stop preventing farther movement, & both pinions thence-
forward slip on the friction driver R during the farther travel of the lift. The
action of stopping the machine replaces the rheostat arm in the original
position in the manner previously described, and in doing so pulls back the
rack which had last been actuating it, the slipping pinion device rendering
this possible. If the lift is to be restarted in the same direction as before the
same actuating rack is now in position for repeating its duty; while if the
opposite direction is given to the lift, the other rack is in position to take up
the pulling motion.
In some cases the rheostat arm F is required to move through a greater angle
than 90 degrees. We then employ another device for returning it to the start-
ing position. The arm F Fig. 7 has attached to its centre a pinion X embraced
by a looped toothed rack. Y, secured to one end of the returning cam lever L.
Assume
The cam J in this case gives downward motion only to the lever L.
as before that all resistance is in & the motor standing. To start in either
direction the returning cam J is turned out of the way of its own lever L, as
shewn by dotted lines & the course is then clear for the pinion X to revolve,
giving motion to the looped rack Y linked to the cam lever L, which is stopped.
at the desired point by again coming into contact with its cam J. The resist-
ances are now all out, & thence-forward the coupling of the form shewn in
Fig. 3 slips as before. To re-insert resistances, the returning cam J is again
placed in the reverse position. With this device a complete circle may be
described by the rheostat Farm if desired.
In some cases it might be objectionable to cut out the resistances with the
intermittent motion of a simple ratchet. We then duplicate the actuating wave
Owheel B Fig. 1 on the winding drum shaft A, its lever C, & accompanying
ratchet wheel E, & by arranging the wave wheel prominences to alternate we
obtain a continuous motion of the rheostat arm F.
In cases where there is no drum shaft K in the controlling or reversing gear,
there will certainly be some oscillating lever gear to which a mechanical equiva-
5 lent of the double acting returning cam J can be attached, by which the same
re-inserting movement may be produced.
Still considering the case of winding drum machines, we find it convenient

page_text: .
in some instances to mount the wave wheel or cam on an independent spindle
of its own, receiving motion from any revolving portion of the machine, by
means of spur or worm gearing, pitch chains or belts; in the latter case the
belt may be adjusted to slip & the slipping coupling dispensed with.
In some cases we dispense with the wave wheel & use in its place a crank
pin, or eccentric with connecting rod to reciprocate the ratchet.
In the case of screw machines the wave wheel or its equivalent is attached
to any of the non-travelling rope wheels; or we dispense with it entirely, &
use a waved rack or rod B Fig. 8 of the same length & travel as the screw; or in
other cases we drive the wave wheel by means of an endless band or chain,
attached to the travelling crosshead on the screw.
In some cases we avoid the use of slipping coupling in the following manner.
Instead of using a complete ratchet wheel with continuous motion, we employ
a toothed are of a wheel as Fig. 9, or a straight rack, the toothed length 6 b¹
being only that necessary to give the requisite movement to the switch. Beyond
the last tooth 61 the surface of the rack rises in a short inclined plane c up which
the tip of the pawl d slides on arriving at that point Fig. 10. The pawl d is in
this case provided with a pivotted bob in unstable equilibrium, so that the
sliding of the point up the incline e tips the bob over & out of gear as in
Fig. 10, & once in this position the switch arm F & ratchet wheel a attached
may be pushed back for slowing speed or stopping, while the pawl d still recipro-
cates clear of it. But the ratchet wheel segment carries at the other end a
reverse incline e, which when brought back to the stopping or full resistance
position, trips the pawl bob the other way Fig. 11, throws it again into gear,
& immediately the machine restarts, the pawl again proceeds to work the rack
over & cut out resistance. The toothed segment of ratchet wheel, Figs. 9, 10
& 11 can obviously be replaced by a toothed rack similarly arranged. The
reciprocation of the pawl & re-insertion of resistance are produced in the manner
previously described.
We carry out that portion of our invention relating to the reversing switch
in the following manner. We arrange along a slate or other insulating founda-
tion four parallel rows of contact pieces Fig. 12, each row having any desired
number of contacts not less than four. For illustration we assume each row consists
of six. Let the rows be distinguished by letters a, b, c, & d; & the contact
pieces by numbers 1 to 6 in each row; the individual contacts may then be
designated a, b, do, etc. In each row the distances between contacts 1 & 2,
3 & 4, 4 & 5, 5 & 6, are all equal; but the distance between 2 & 3 in each row
is one half greater. The distance from row to row is immaterial except for con-
siderations of insulation. Contacts a¹, a², & a³, are electrically connected; a
& a are also coupled. Contact ¹, is connected to the negative main; 62 to
the positive main; 63 and 64 are coupled; 65 & 66 are coupled, & 66 is also connected
to one of the motor brushes. Contact c¹ is connected with the positive main;
to the negative main; & care coupled; & care coupled, & c is also
connected with the opposite brush of motor. Contacts in row d are coupled
exactly as in row a.
A carrier bar f sliding endwise in suitable guides, lies along the centre between
rows a and b parallel with them, and a similar bar fi lies between rows c and d.
These bars are rigidly coupled together so as to move simultaneously. Each bar
carries five insulated bridges gg etc., placed in such positions that they will as
regards the first bar connect a² to b², a³ to b³, a to b*, as to b³, and a6 to 66; and
as regards the second bar connect to d², c³ to d³, to d, to d³, & co to do.
Under these conditions the circuit is from positive main through b², a², a³, b³,
b, a, a, b, b6, to first commutator brush, through armature to second brush,
thence through cº, c³, d³, d³, c¹, c³, d³, d², c² & thence to negative main. Con-
tacts and are idle being merely supports for the ends of the last bridges
when in this position. Contacts a¹, b, c¹ & dare also idle in this position.

page_text: If now the pair of sliding bars are moved endwise sufficiently to break contact
etween the various bridges & the contact plates, the circuit will have been
roken simultaneously at nine points along each main, or eighteen in all,
s in Fig. 13.
Farther, assuming that the bridges have moved away from pairs of contacts
on their left, & that the motion is continued they will reclose the circuit by
making contact between the pairs of contacts on their right as in Fig. 14; and
the direction of the circuit will now be reversed, for it enters from positive main
at el, passes through d¹, d², ³, c³, c³, d², d³, c, to what. was previously the
negative brush but is now the positive, through motor to opposite brush,
to b6, 15, a, a, 14, b³, a², a², a, b, and thence to negative main. In this cir-
cuit, contacts a6, 12, 2, & 6 are idle, as are the two bridges lying near the four
No. 2 contacts.
When this circuit is opened, it is broken at eight points in each main, or
sixteen in all.
It is obvious that the system may be extended indefinitely, the addition of a
pair of contacts and one bridge on one line adding two extra breaks, with a
similar result from a similar addition on the other line. Conversely the system
may be reduced by the omission of similar sets, till the minimum complete
system is reached. This consists of rows of four plates each, with three bridges
in each line.
In cases where this elementary system is found sufficient, we simplify the
arrangement in the following manner, premising that this modification does not
lend itself so well to indefinite extension as does the arrangement first described.
The contact plates are arranged in four rows Fig. 15, which may still be
designated a, b, c, & d, each row having four plates numbered 1 to 4. All the
plates in row a are connected together. Plate 6' is connected with the positive
main 2 with the negative main; 63 & 4 are coupled, and 6 is connected with
one commutator brush. Plate c¹ is connected with the negative main; c² with
the positive main; & care coupled, and c is connected with the other com-
mutator brush. Plates in row dare all coupled together. A sliding bar f
for carrying bridges g g lies as before between rows a & b, and another bar fi
between rows c & d; each bar carries two bridges. In the position first to be
considered, the bridges will couple a¹ & a respectively to b¹ & b³, & also c¹ & c³
respectively to d¹ & d³.
The circuit thus made will be from positive main through b', across bridge
to a¹, thence to a², & a, by bridge to 63, & 4, through armature to c & c³, by
bridge to 3, thence to d & d¹, by bridge to c¹ which is negative main terminal.
If now the bridges be moved as in Fig. 16 so that they lie midway between
O plates 1 & 2 & between 3 & 4, the circuit will have been broken at eight points
simultaneously.
If the bridges be moved still farther as Fig. 17 so that they lie on all the
plates numbered 2 & 4 the circuit will be reclosed, but in the opposite direction:
for it now enters from positive main, at 2, & proceeds by d², d³, d* & c, through
5 armature to 64, & on by as, a³, a², & b² to negative main. A return of the
bridges to the mean position, opens this circuit also at eight points simul-
taneously.
In this arrangement four coupling bridges suffice instead of six.
Having now particularly described & ascertained the nature of our said inven-
50 tion, & in what manner the same is to be performed, we declare that what we
claim is:-
(1). In an electric lift, hoist, or crane, driven by direct coupled motor &
hauling drum, the automatic device for cutting out & re-inserting resistance
as described & illustrated in Figures 1, 2 & 3, and using one or more wave
55 wheels.
(2). In an electric lift, hoist, or crane, driven by direct coupled motor &

page_text: hauling drum, the automatic device for cutting out resistance as described &
illustrated in Figures 4, 5 & 6.
(3). In an electric lift, hoist, or crane, the combination of the automatic
cutting out device illustrated in Figs. 4, 5 & 6 with the re-inserting device
illustrated in Figures 1, 2, & 3.
(4). In an electric lift, hoist, or crane, driven by direct coupled motor &
hauling drum, the automatic device for cutting out & re-inserting the resist-
ance as described & illustrated in Fig. 7, combined with ratchet gear as illus-
trated in Figs. and 2.
(5). In an electric lift, hoist, or crane, driven by direct coupled motor and
screw hauling gear, the combination of a waved rack or bar for cutting out
resistance as described & illustrated in Figure 8, with the re-inserting devices
illustrated in Figs. 1, 2, 3, & 7.
(6). In an electric lift, hoist, or crane, with direct coupled motor and screw
hauling gear, the combination of cutting out and re-inserting devices as illus-
trated in Figs. 1, 2, 3, 4, 5, & 6 with a belt, rope, chain or other equivalent
driving device to give rotatory motion to the wave wheel, or pinions, as described.
(7). In an electric lift, hoist, or crane, with direct coupled motor and hauling
drum, the automatic devices for cutting out & re-inserting resistance described
& illustrated in Figures 1, 2, 3, 4, 6, & 7, the wave wheel or pinions being
mounted on an independent spindle or arbor, and driven by belt, rope, or chain
from any revolving portion of the machine, as described.
(8). In an electric lift, hoist, or crane, with direct coupled motor, the auto-
matic ratchet or rack device for cutting out resistance as described & illustrated
in Figs. 9, 10, & 11.
(9). In any machine driven by a direct coupled reversing electric motor,
the application of any of the automatic devices for cutting out & re-inserting
resistance described & illustrated in Figures 1 to 11.
(10). Multiple break reversing switches as described and
Figures 12, 13, & 14.
illustrated in
(11). Multiple break reversing switches as described and illustrated in
Figures 15, 16, & 17.
(12). In any reversing electrical machine the combination of the resistance
controlling devices as described & illustrated in Figs. 1 to 11, with the reversing
switches as described & illustrated in Figs. 12 to 17.
TAIL
CA
JOHN S. STEVENS,
CHARLES GEORGE MAJOR,
EDWIN CHARLES STEVENS,
PERCY HERBERT STEVENS.