Improvements connected with Electric Elevators and Motors.
Year: 1892

page_text: Date of Application, 20th Jan., 1892-Accepted, 20th Feb., 1892
COMPLETE SPECIFICATION.
Improvements connected with Electric Elevators and Motors.
A communication from abroad by OTIS BROTHERS & Co., of 38, Park Row,
New York, in the United States of America, Manufacturers.
We, AMERICAN ELEVATOR Co. (Incorporated) of 4, Queen Victoria Street,
in the City of London, Manufacturers, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
This invention relates to electric elevators, and more especially to means whereby
an electric elevator may be readily and safely operated to run at varying speeds
in connection with ordinary systems of distribution of electric current.
It is well known that in operating electric elevators, it is necessary to provide
means whereby the speed of the elevator may be regulated, so as to run properly
under varying londs and to be stopped and started without sudden jars or jolts, and
without danger of burning, or otherwise injuring the electrical apparatus. It is
also desirable to regulate the speed of the elevator for the purpose of inspection.
In order to effectually operate an electric elevator, it is necessary to have a
switch for controlling the current in stopping and starting and for reversing the
current of the motor, and heretofore it has been customary in practice to put the
switch in some stationary position near the motor, although it has been proposed
to place the controlling switch on the moving car. This, however, has been
open to objections for the reason that the circuit wires leading from the motor to
the travelling car are usually made flexible, and enclosed in a flexible tube, and
when the current of great quantity is passed through the motor, and through
these connecting wires there is a liability of burning or injuring the conductors or
of the insulation being impaired, which would result in short circuit. Furthermore,
having a current of considerable quantity controlled by a switch board on the car,
there is liable to be considerable sparking, which is annoying and perhaps dangerous
to the passengers in the car.
One of the objects of the present invention is to overcome these objections, and
to provide means whereby the switch may be mounted on the car and travel there-
with, and be operated without danger of sparking, burning or otherwise interfering
with the circuits. In order to accomplish this the circuits are so arranged that
only the wires leading to the field magnets are connected positively with the switch
device on the car, while the armature circuit over which a varying quantity current
is passed according to the work to be done is entirely independent of the car and
the switch thereon.
In connection with this object of the invention further results are accomplished
in the way of automatic regulation of the current through the armature, which
will be more particularly pointed out hereinafter, and further the resistance of the
fiid magnet circuit is controlled in the manner hereinafter set forth.
in order that the invention may be more clearly understood reference is made to
the accompanying drawing, in Figure 1 of which is shown diagrammatically one
embodiment of the invention, sufficient to explain the principles thereof, and enable
those skilled in the art to readily apply it in practice.
In the drawing A, represents the ordinary winding drum around which passes
the elevating rope B, which is attached to the car B', passing over the suitable
sheaves B2, in the usual manner. Mounted on the car B1 is a switch device S, the
circuits leading therefrom being as usual enclosed in a flexible tubing, so that the
connection will be properly maintained as the car moves up and down. This
switch device may be of any suitable construction, but the preferred form is shown
which consists essentially of a pivoted arm S¹, mounted to be operated by any

page_text: suitable device, as a crank or handles, and so arranged that in its normal position
no current passes through the switch. Arranged on either side of this switch arm
are a series of contacts suitably connected, so that the direction of the current
through the switch will be controlled by moving the switch arm either to the right
or to the left in the manner well understood. As before stated, the circuits of the
motor and switch are so arranged that only the current which passes through the
field of the motor is led to the switch device, the current passing through
the armature being either mechanically or preferably automatically controlled on
moving the switch controlling the circuit through the field.
To more particularly describe the circuits let 1, represent the plus binding post
which is connected with the feeding wire of any ordinary system of distribution.
From this post a wire 2, leads to the pivot point of a switch m, which is a properly
insulated, and the handle m', of which is connected electrically with the solenoid b,
from whence the current passes by the conductor 3, to the plate or sector 4, of the
switch. Arranged around this sector and the corresponding sector 5, of the
opposite side of the switch are a series of contact blocks 7, 8, 9, the blocks being
connected by suitable resistances 10 and 11. These contact blocks on either side
of the switch arm are suitably connected, so that the resistances will be properly
included in the circuit, regardless of which way it is moved, only the direction
through the resistances will be varied. The arrangement is such that when the
switch arm is moved to the right or to the left over the first contact block no
resistance is in the circuit, but as it reaches the second contact block, a resistance
of a predetermined amount is included in the circuit, and so on to the other contact
block, there being as many as may be desired, according to the specific requirement
of any particular case, it being understood that as the switch is moved further
from its normal position more resistance is included in the circuit at each contact
block, as the arm is moved to the right or left to change the direction of the current.
For instance assuming the switch arm S', to be moved onto the contact 7, the con-
ducting portion of the switch arm will complete the circuit between the sector 4,
and the contact plate 7, and thence it will pass by the wire 12, directly to the field
magnet coils, of the motor, and then by the wire 13, back to the sector plate 14,
and by the conducting portions, of the switch arm to the sector 5, and by the
conductor 15, to the minus binding post, 16. It will thus be seen that as soon as
the switch arm S', is moved, the circuit of the field magnet is completed, and the
full potential of the current passes through the field, and this is supposed to be a
constant potential current having a uniform voltage. When, however, the switch
is moved to the contact 8, the resistance 10, is included in the field magnet circuit,
and the voltage of the current through the field coils of the motor is reduced and
so on through the other resistance devices at the switch.
The switch m controls the armature circuit of the motor, and the arm m³, of the
switch is preferably weighted as at m², or provided with a spring m³, or possibly
both, which has a tendency to maintain the switch m, open. When, however, the
circuit is completed by the switch on the car, the coils of the solenoid b, are
energized, and this solenoid operates to close the switch m, and complete the
armature circuit. From the switch m, passes a conductor 17, leading to a solenoid c
from whence it passes to the brush g, of the armature, through the coils thereof to
the brush g', and in the present instance to the coil of the solenoid i, and to the
brush of the safety resistance device, and thence to the binding post 16. It is
to be remarked that the current through the armature is always maintained in the
same direction, the motor being reversed by reversing the current through the field
magnet coils.
The solenoid c, is arranged to operate a brake device for stopping and holding
the motor, which is diagrammatically indicated in the drawings, in which d,
represents a lever pivotally mounted at d', and provided with a suitable weight or
spring, which normally holds the brake against some moving part of the motor
or its connected mechanism, as for instance on the armature shaft. When, how-
ever, the coils of the solenoid c, are energized by the current passing therethrough,

page_text: the core of the solenoid is raised, releasing the brake device, and maintaining it
out of operative position as long as the current flows through the armature circuit
in proper quantities. While it is preferred to use the solenoid c. the brake device
can be mechanically connected to the switch arm m, to be operated by the
solenoid b, as indicated by the dotted lines, and the spring or weight attached to
said switch m, would operate to apply the brake as soon as the current is cut off.
The safety resistance device k, is arranged in the armature circuit, and its
brush j, is normally in position to include this resistance in the armature circuit, and
in order to insure this normal position of the brush j, mechanical means are provided
which in the present instance are shown as being operated by the brake lever d.
Thus lever e, is shown preferably provided with a weight e', which will normally
rest upon the brake lever d, or in preference to this it may be a mechanical
connection, and further provided with a bifurcated end e², arranged to operate the
brush j. This brush j, is provided with means which tend normally to move it in
a position to cut out the resistance k, and lever is shown having a weight or
spring, which will move the brush when free to cut out the resistance k. To
further control this, however, the solenoid is provided, the coils of which are
so arranged that its core, is also connected to the brush and controls its
movement.
.
Such being the preferred arrangement of the devices, its mode of operation will
now be described. The switch arin S', is shown in full lines in its normal position
with no circuit through the field, but for convenience of explanation, the current
through the armature is shown completed, it being supposed that the switch
arm S, is moved to one or the other of the contacts, it being indicated in dotted
lines as bearing on contact 9. As soon as the circuit is completed at the switch
between the segment 14, and contact 7, the field is energized with the full current
from the line and the solenoid is also energized, instantly closing the switch m, of
the armature circuit. This closing of the armature circuit, will release the brake
device by the mechanical connections shown in dotted lines, or by energizing the
coils of the solenoid c, and the brake will be moved away from its bearing surface.
The lever e, either by its mechanical connections, or the weight el will be tilted to
raise its bifurcated end e', in a manner to release the brush j, and allow it to be
operated by its weighted lever 1, to cut out the safety resistance k, if it were not
otherwise controlled. The current of the solenoid i, however, under these conditions,
is sufficiently strong with the safety resistance k, in the circuit to hold the brush
with its weighted lever at the point indicated to include said resistance, and the
motor starts under a limited quantity of current. As soon, however, as the
armature commences to rotate, producing counter-electro motive force, the speed
of the current passing through the coils of the solenoid, is decreased proportionately
or relatively, and the weighted lever 1, operates to move the brush to cut out more
or less of the safety resistance coils k, and when the armature attains its normal
speed, the adjustments are such that the whole of the safety resistance is supposed
to be cut out. If, however, the current through the armature is increased above
its norinal, the solenoid i will operate to cut in more or less of the safety resistance,
and it thus becomes a safety device to regulate the quantity of current and prevent
injury to the motor.
When the motor is to be stopped, the switch arm S', is moved to its normal
position, breaking the circuit through the field magnet coils of the motor, and of
course releasing the switch arm m, which is immediately operated to break the
circuit of the armature by the weight or spring. At the same time, the brake
lever d, is operated to apply the brake to the motor by its weight or spring, and
this in turn operates the lever e, causing its bifurcated portion e, to mechanically
draw the brush j, to the position shown in the drawing, where it is held as long as
the brake is applied, the safety resistance k, being in the circuit, and thus the parts
remain until the field magnet circuit is again closed.
Of course it will be understood that if the switch arm were moved to the right
instead of to the left as shown in the dotted lines, the same operations would occur,

page_text: the only difference being that the current through the field magnet coils would be
in a reverse direction, causing the motor to rotate accordingly.
It is well known that a motor runs slower when the field is fully saturated (other
things being equal) than when a less current is Howing through the coils of the
field, and in order to increase the speed of the motor under the conditions shown
in the drawings, means controlled by the switch in the car are provided whereby
the current flowing through the field magnet coils can be varied. Thus it will be
seen in the arrangement described that when the switch arm S, is moved to the
first contact, right or left, the full current from the main line passes through the
field magnet coils in one or the other direction, and the motor is started. When,
however, the switch arm passes to the next or other succeeding contact of the
switch, more or less of the resistance coils 10, 11, are included in the field magnet
circuit, and as a consequence, less current flows through the coils of the field
magnet, and the speed of the motor will be increased, and this is done without in
any way affecting the current passing through the armature.
While the preferred embodiment of the invention has been thus described and
illustrated, it is evident to those skilled in the art that the principles thereof may
be applied in various ways to suit the exigencies of any particular case, and the
invention is therefore not limited to the precise construction and arrangement of
parts set forth.
In some instances to operate the switch m, controlling the armature circuit, from
the car there may be arranged an ordinary travelling rope (indicated by dotted
lines) connected to the car and the switch m, and adapted to be operated in the car
by the lever, in a manner well understood.
It is evident that by the use of this invention a practical way is provided of
utilizing a controlling switch for the motor when mounted on the car thus avoiding
the danger of passing the armature current through the switch, and its connecting
wires, it being understood that there is little variation in the strength of the current
of the field magnet coils, the amperage of which is always low, for instance in
some conditions not more than one ampere, and when the resistance is included, of
course even this amperage is reduced, the potential remaining the same; while in
the armature circuits a relatively considerable amperage is used, according to the
circuit to be done, and the dangers of passing this quantity of current through the
switch and its connections are avoided.
When the apparatus is fully in motion as a general thing only a portion of the
whole current is required to maintain it in operation, and therefore the switch in
such cases need only occupy a position so as to keep in a portion of the resistance;
but when the apparatus is started the surplus of power necessary to overcome the
friction of rest and inertia of the mass demands that all or a greater portion of the
resistance be cut out, after which the normal running condition of the engine can
be maintained with a current of less power.
Different means may be employed for securing such a movement of the switch
or stopping and starting device as will insure the surplus of power necessary in
starting and bring the automatic switch or device to a position to cut off or out a
portion of the current and reduce the power for normal running. Thus in Figs. 5
& 2 the switch is connected through the medium of a pinion 16, on the switch shaft
and a sector toothed lever 17, pivoted to the frame, with a shifting bar 18, sliding
in bearings on the frame and said shifting bars are connected by rack lever 19, and
pinion 20, with a pulley 21, turning on a shaft 12. Around this pulley passes a
cable 23, leading to the cage of the elevator and the adjustment of which shifts the
bar 18, and the switch 14.
Below the bar 18, are pivoted two bell crank levers b,, each having a short
arm 25, projecting upward and a long arm 26, projecting horizontally and forked
or recessed for the passage of a rod 27, extending from a weight 28, that normally
occupies a position upon the base. To the bar 18 are secured two tappets or
contacts 30, 30, so arranged that when the bar and switch are in a mid-position
the said tappets will be between the two upright arms 25 and out of contact

page_text: therewith so that when the operating rope is moved the bar 18, will be shifted
to one side or the other to carry the switch to its extreme position to either
side thereby throwing the entire current into the motor and giving the surplus
power necessary to start the engine. As the bar 18, approaches its extreme
position, however, one of the contacts 30, meets one of the arms 25 and thereby
tilts the lever, so as to lift the weight 28, and when the operating cord is
released the weight will restore the lever to its original position and carry
the bar 18 back to a slight extent from the extreme position from which it was
moved thereby cutting in a portion of the resistance and reducing the current to
the extent required for normal operations.
In the construction shown in Fig. 3, the return movement of the shifter bar is
effected by means of a spring 31, connecting two blocks 32, 32, mounted upon a
bracket 33, in position to be struck by the lugs 30, 30. In the construction shown
in Fig. 4, the return movement of the shifter bar is effected through the medium of
two pivoted arms 35, 35, connected by the spring 31, which brings both against
bearings, 36, 46, and the contacts 30, are brought against the ends of the same by
the movements of the shifter bar.
A weight, springs or other motor means may act upon a shifter bar to carry the
switch back to a certain extent from its extreme position, and such means may be
arranged to act upon any part of the apparatus that is moved with the switch
or other stopping and starting device. For instance the said motor means may
act upon the operating lever 40, in the cage. In another construction shown in
Fig. 2, there are in the cage two pivoted arms 41, 41, connected by a spring 42,
which holds each in contact with a stop 43, and when the lever 40, is carried
towards its extreme position, it strikes a stud 44, on one er other of the arms and
swings the latter so as to extend the spring, and when the lever is released the
spring carries it back part way towards its central position thereby shifting the rope
or cable and the switch connected therewith.
While the above described improvement has been illustrated and referred to in
connection with an elevator apparatus it will be evident that it may be employed
with various electro-motors where it is necessary to temporarily use a maximum
power to start the motor and thereafter decrease the power to maintain the motor
in
its normal running condition.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to us by
our foreign correspondents, we declare that what we claim is:-
1. In an electric elevator, the combination with the motor and car operated
thereby, a switch located on the car, of circuit connections between the field
magnet coils of the motor and the switch on the car, substantially as described.
2. In an electric elevator, the combination of the motor connected to operate
the car, of a switch mounted on the car, the field magnet coils of the motor being
connected to the switch and controlled thereby, while the armature. circuit is
automatically controlled, substantially as described.
3. In an electric elevator, the combination with the motor and car operated
thereby, of a switch carried by the car and circuits and connections substantially
as described, whereby the field magnet circuit only travels with the car, as and for
the purposes set forth.
4. In an electric elevator, the combination with the motor and car operated
thereby, of a switch mounted on and travelling with the car, circuit connections
between the field magnet coils of the motor, and the car, and means substantially
as described outside of said switch for controlling the armature circuit, as and for
the purpose set forth.
5. In an electric elevator, the combination with the motor and car operated
thereby, of a switch travelling with the car, circuit connections between the field
magnet coils of the motor, and the switch and armature connections controlled
by said field magnet circuit, substantially as described,

page_text: 6. In an electric elevator, the combination with the motor and car operated
thereby, of a switch mounted on the car field magnet circuits between the motor
and the car, and electrical devices controlling the armature eircuit and controlled
by the field magnet circuits, substantially as described.
7: In an electric elevator, the combination with the motor and car operated
thereby, of a switch mounted on the car, the field maguet coils of which are
connected to the travelling switch, and a magnet in said field magnet coils
controlling the circuit of the armature of the motor, substantially as described.
8. In an electric elevator, the combination with the motor and car operated
thereby, of a switch mounted on the car connections between the switch and the
field magnet coils of the elevator, a switch controlling the armature circuit and
controlled by the field magnet circuit, and an automatic brake device also controlled
by the field magnet circuit, substantially as described.
9. In an electric elevator, the combination with the motor and car operated
thereby, of a switch on the car controlling the field magnet coils of the motor, a
switch controlling the armature circuit of the motor, a brake for the motor, a
safety resistance device, and connections between the safety resistance device and
the brake whereby the brake is applied and the safety resistance is positively
included in the circuit of the armature, substantially as described.
10. In an electric elevator, the combination with the motor and car operated
thereby, of a safety resistance in the armature circuit, a brake for the motor and
connections between the safety resistance and brake for controlling said resistance,
substantially as described.
11. In an electric elevator, the combination with the motor, of an armature
eircuit including a safety resistance, a brake for the motor, connections between
the safety resistance and brake, and a solenoid also in the armature circuit for
controlling the safety resistance, substantially as described.
12. In an electric elevator, the combination with the motor and car operated
thereby, of an armature circuit, a brake for the motor, a solenoid in the armature
circuit controlling the brake, a safety resistance in the armature circuit, connections
with the brake for operating the safety resistance, and a solenoid in the armature
circuit controlling the operations of the safety resistance, substantially as described.
13. In an electric elevator, the combination with the motor and car operated
thereby, of a switch mounted on the car connections between the field magnet coils
and the switch, an armature circuit controlled by the circuit of the field magnet
coils, and a brake and safety resistance controlled by the armature circuit
substantially as described.
14. In an electric elevator, the combination with the motor and car operated
thereby of a switch device mounted on the car, connections between the field
magnet coils and the switch device, and resistances in said switch device arranged
to be included in said field magnet coils, substantially as described.
15. In an electric elevator, the combination with the motor and car operated
thereby, of a switch device mounted on the car, and connections with the field
magnet coils of the motor, the switch being provided with contact resistance
devices arranged substantially as described, so that when the circuit is closed the
full current passes through the field magnet coils and when the switch is moved
further, the resistance is included in the field magnet circuit to increase the speed of
the motor, as and for the purpose set forth.
16. In an electric elevator, the combination with the motor and car operated
thereby, of a switch mounted on the car, a circuit between the switch and field
magnet coils, a solenoid in said circuit, a switch operated thereby and controlling
the armature circuit, and resistance devices on the switch arranged to be included
in the field magnet coils to vary the speed of the motor, substantially as described.
17. The combination with an electric-motor and with the controlling device
thereof, of means, substantially as described, for automatically moving said device
from the extreme position in which it is set in throwing the full current into
the motor.

page_text: 18. The combination with an electric-motor, controlling device thereof constructed
to regulate by its position the current passing through the motor, a weight or spring
and connections between the same and movable parts arranged in position to be
struck by contacts connected with the controlling device, substantially as set
forth.
19. The combination with an electric motor and controlling device of a shifting
bar connected with said controlling device and provided with contact pieces and
moveable pieces in position to be struck by said contact pieces as the bar approaches
the limit of its movement in each direction and a weight or spring connected to
restore the parts to their normal position, substantially as set forth.
20. The combination of the electric motor and its switch the bar 18 connected to
turn the switch and provided with contacts and two movable arms arranged to be
struck by said contact and connected with a weight or spring, substantially as
described.
Dated the 20th day of January 1892.
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London, Agent for the Applicants.