Improvements in or connected with Electric Cranes.
Year: 1899

page_text: Date of Application, 29th June,
Complete Specification Left, 28th Apr., 1900-Accepted, 23rd June, 1900
Improvements in or connected with Electric Cranes.
I, JAMES GEORGE WILLCOX ALDRIDGE, Engineer, of 9, Victoria Street, in the
County of London, England, do hereby declare the nature of this invention to be
as follows:-
1
This invention for improvements in or connected with electric cranes has for
its object to improve the controlling devices and consists in arranging the con-
trolling lever of the electric motor driving the hoisting drum to also actuate the
clutch that connects the drum to the motor so that at the first operation of the
lever the clutch is put into gear and then the starting resistances are successively
cut out. On the return motion of the lever the drum is entirely disconnected so
that it is free for descending loads and is controlled by a hand, foot, or other
'
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C.,
Agents.
Improvements in or connecto
I, JAMES GEORGE WILLCOX ALDRIDGE, Engineer, of 9, Victoria Street, 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-
This invention for improvements in or connected with electric cranes has for
its object to improve the controlling devices and consists in arranging the con-
trolling lever of the electric motor driving the hoisting barrel to also actuate the
clutch that connects the barrel to the motor so that at the first operation of the
lever the motor and resistances are put into circuit and the clutch is put into
gear and the starting resistances are successively cut out. In the initial position
of the lever the barrel is entirely disconnected so that it is free for descending
trolled by a hand,, foot, or other brake,

page_text: In the accompanying two sheets of illustrative drawings, Fig. 1 is a sectional
elevation of a controlling device constructed according to this invention, showing
the device applied to the barrel of a crane, and Fig. 2 is a sectional plan of the
same. Fig. 3 is a diagram showing the electrical connections.
The barrel a is mounted loosely on the main shaft b. A projection d¹ on one
end of a volute spring or coil works between stops c on the barrel and the
other end of the coil is engaged by a lever fulcrumed on the drum at c¹.
The volute or coil spring d surrounds a friction block or drum f keyed on the
shaft band when the lever e is operated it grips the drum f and so locks the
barrel a to the drum f and thus to the main shaft b. The spring 9 tends to
loosen the coil d from off the drum f. The main shaft bis driven by worm
or other suitable gearing from the electric motor. The lever e is operated by
the disc that slides axially on the shaft and rotates with it. The sliding
disch is connected to the operating handle through the shaft 1, arm 2, link 3,
lever 4 and spring link 5 connected to the arm 60 on the fork shaft 6 provided
with two prongs 7 that engage in the groove in the disc h.
The operating handle is also connected to the electric switch through the
shaft 1, arm 2, link 8, arm 9, shaft 10, arm 11, spring link 12, arm 13, shaft 14
bevel sector 15 and bevel wheel 16 fixed on the switch shaft m. The switch /
is connected to suitable resistances R1 R2 R3 R4 R5, to the motor armature m
and field magnets n and to the spark extinguisher O. The diagram Fig. 3 show-
ing clearly the arrangement for representing the brushes and B the development
of the contact strips in the circular switch.
The barrel a is also provided with a brake band acting on the brake surface a¹
and operated through the lever link 17, arm 18 shaft 19 and foot lever 20
fixed on the shaft 19.
If the lever is in the zero position, the contact hammers bear on the con-
troller on the line marked 0 (zero) in the diagram and no current whatever can
pass. In this zero position the field magnets M are short circuited. If the lever is
moved to position notch 1, the armature A magnets M and resistances R' R² R³ R* R³
are all in series and the minimum current passes and so the motor runs at its
minimum speed.
As the lever is successively moved to notches 2, 3, 4, 5 and 6 the resist-
ances R R R R2 and R¹ are in turn all cut out, and at notch 6 the armature A
and the magnet M are directly in series across the mains. In the notch 7
position the resistances R¹ R2 and R3 are in parallel with the magnets and in
the position notch 8, only the resistance R is in parallel with the magnets and
the motor runs at its maximum speed. Moving back the lever to notch 00
shortcircuits the armature, magnets and resistances which are all in series, hence
no current from the supply can pass through the motor; the latter being thus
abruptly shorcircuited comes to a stop at once and thus prevents the load or the
empty hook from rising too far.
It will readily be seen that the spring link 5 allows of the continued motion
of the lever i even when the clutch is tight.
The electric motor controller, the barrel clutch and the brake shown on the
drawings are wellknown contrivances and may be replaced by other similar
known contrivances without departing from the nature of this invention.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. The improved controlling device for electric cranes consisting of a clutch
connecting the motor to the crane barrel, an electric controller for regulating the
motor and a lever operating both the clutch and the electric controller.
2. The improved controlling device for electric cranes consisting of a clutch
connecting the motor to the crane barrel, an electric controller for regulating the

page_text: motor, a lever operating both the clutch and the electric
brake acting on the barrel.
3. The improved controlling device for electric cranes substantially as described
with reference to the drawings.
AD
000
WHEATLEY & MACK
40, Chancery Lane, London, W.C.,
Agents.