Year: 1888

page_text: We, ROOKES EVELYN BELL CROMPTON, JOHN FRANCIS ALBRIGHT, & JORGEN
HEINRICH FFRDINAND SOLL, of Arc Works, ('helmsford, in the county of Essex,
Electrical Engineers, do hereby declare the nature of this invention to be as
follows.-
-
Our invention has reference to the application of electrical power to cranes & hoist,
of various kinds, such as stationery or locomotive jib cranes, travelling cranes of
various sorts and to hoists & lifts
Hitherto it has been the custom to work such cranes by means of electric motors
of high speed geared to the hoisting birrel by the usual train of gear wheels the
movement of the crane being effected by the motor being started, stopped or reversed
This introduces considerable
according as the load is to be raised, held or lowered
trouble with the commutator of the electric motor, it is also difficult to control tho
speed of the actuating motor as in the case where the motor has to be frequently
started and stopped it is usually wound with the field magnets in series circuit to the
armature To obviate these difficulties in our improvements we arrange that our
It can therefore be shunt wound and con-
motor runs continuously in one direction
sequently can be easily arranged to hoist at a continuous speed even with a widely
varying load
In one form of our invention we use a motor with a friction pulley
and the fly wheel mounted on its spindle In order to actuate the first wheel of the
train of gearing the motor itself is moved through a small distance so as to bring
the friction pulley into more or less close contact with the smooth surface of
this first wheel We can employ various modes of doing this, either the motor can be
mounted on a pivot so as to be hinged on a spindle parallel to its axis or the motor
can be traversed through a horizontal angle through a plane at right angles to the
plane of its spindle In either case the movement can be effected by a hand wheel
or lever or other convenient mechanism or weight or spring can be so attached
so that the gear can be locked on the core in position by a simple movement of one
lover or core In some cases the usual mechanical brake can be dispensed with and
the matter arranged electrically so that by alterations of the electrical connections

page_text: some of the power given out during the lowering of the lond may be returned usefully
to the generating source This can be done in the case of a shunt motor by making the
motor large for its work ind weakening the magnetic field at the time it is ordinarily
used as motor & by strengthening it (by taking out resistance) at the time it nets
as generator returning power to the line
Dated this 98th day of May 1980
Improvements Connected with Electrical Hoists or Cranes
We ROOKES EVELYN BALL CROMPTON JOHN FRANCIS ALBRIGHT & JORGFN
HEINRICH FERDINAND SOLL of Arc Works Chelmsford 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 to the application of electrical power to cranes &
hoists of various kinds such as stationary or locomotive jib cranes travelling cianes of
various sorts and to hoists & lifts
Hitherto it has been the custom to work such cranes by means of electric motors
of high speed geared to the hoisting barrel by the nsual train of gearing wheels the
movement of the cine being effected by the motor being started stopped or reversed
according as the load is to be raised held or lowered This introducts considerable
trouble with the commutator of the electric motor It is also difficult to control the
speed of the clectric motor is in the case where the motor has to be frequently started
ind stopped, it is usual to wind the field magnets on the series system
To obviate
these difficultics, in our system we arrange that the motor runs continuously in one
direction, the motor can therefore be shunt wound, and will run at an approximately
const int speed with a widely varying load The drawings show one method of
carrying this out The motor M has a function wheel P mounted on its spindle, in
order to actuate the train of gearing, the motor itself is moved through a small
distance so is to bring the friction wheel P into more or less close contact with W
the hrst wheel of the trun of geiring We can employ various modes of do ng this,
either the motor may be mounted on pivots A so that it swings about
to its own spindle, or it may be moved through horizont il ingle m
right angles to its own spindle In either case the movement may be
line parallel
direction at
effected by a

page_text: hand wheel or lever L, or other convenient means, and a weight or spring may be so
attached that the gear can be locked in position by a single movement of the lever
or hand wheel The usual mechanical brake may be dispensed with, and the motor
itself made to act as a brake, by making it work as a dynamo, instead of a motor,
thus returning to the generating source some of the power given out by lowering the
load This can easily be done in the case of a shunt motor, if the motor is large for
its work, by weakening the field, when it is running as a motor by inserting resistance
in the shunt circuit, and strengthening the field when it is required to run as a
dynamo
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 In electrical cranes & hoists & lifts A combination of a shunt wound motor
arranged to run at an approximately constant speed, with widely varying loads,
driving by means of friction gear, operated and arranged substantially as herein
described
2 In electrical cranes hoists & lifts The mode of operating the friction gear by
moving the motor itself through a small horizontal or vertical angle by means of
screw or lever gear substantially as herein described
3 In electrical cranes hoists & lifts The arrangement of utilising the power given
out at the time of lowering the load by means of strengthening the field magnets of
the motor substantially as herein described