Year: 1897

page_text: Date of Application, 14th June, 1897
Complete Specification Left. 12th Mar.. 1898-Accepted, 16th Apr., 1898
I, RICHARD WOLFF, of Heilbronn on the Neckar, Germany, Engineer, do hereby
declare the nature of this invention to be as follows:
:-
The present invention has for its object a safety crank for hoisting cranes, which
permits of the load to be lowered in two different ways; firstly by uncoupling the
device by a short jerk on the crank, 'when the load will sink under a certain
amount of friction, but without any further work on the part of the attendant,
and secondly by following the sinking of the load by turning the crank
backwardly.
In the accompanying drawing
Fig. 1 represents the device in longitudinal section and
Fig. 2 shows a side view of same.
A
of
The socket c, carrying the driving-wheel b, fits loosely over the crank axle a.
disk d fits loosely over the projecting portion c¹ of the socket c and carries ratchet
teeth f on its outer circumference. A second disk k, having no teeth, is attached
The nut h, being
by groove and tongue to the projecting portion c¹ of socket c.
thread 9
provided on its outer circumference with teeth i, engages the square
the crank-axle a. Suppose the crank-axle a is turned in the direction of the arrow
(Fig. 1), the nut h will then press against the disks k and d, and the latter in its part
against the socket c, which by the resulting friction is rotated in the sense of the
crank-axle. The pawls n and o jump the teeth f and i respectively during the
forward motion of the disk d and the nut h. If the crank accidentally or inten-
tionally is let go, these pawls n and o engage the teeth f and i and the load stops.
If it is desired to let the load sink by applying braking down pressure, the crank
is given a short backward jerk, whereby the nut is loosened somewhat. The
stop 7 prevents a too far backward motion of the nut h. The load now overcomes
part of the still existing friction between h, k, d, c, and sinks. A recoiling of
the crank of course, cannot ensue, as the nut h is securely locked by the pawl o
In case the load is to be let down by following the sinking of it with the crank,
the pawl o is to be thrown out, the crank is turned backward and the nut h
loosened. The sinking load, and with it the driving wheel b and socket c, very
soon attain a velocity, which is greater than the crank motion. The nut h con-
sequently is pressed against the disk k again and a further sinking of the load
would thus be prevented, if not, by turning the crank backward, the load would
get a chance again to sink. Practically these backward motions of the crank and
the sinking of the load follow each other in so quick successions, that they are
felt as one continuous motion. If the crank is let go, the load will stop.
The present invention has the great advantage over all similar arrangements,
that the load can be gotten down either by a continuous backward motion of the
crank, or by giving the crank one sudden backward jerk, when the load can be
let down by braking it down. The device can be worked in conjunction with a
centrifugal brake of any well known construction. In order to prevent the

page_text: rattling of the pawl o, while skipping the teeth i of the nut h, a pin o' is pivotally
secured at 03 on the pawl o, the lower, roughened end of which glides upon the
outer circumference of the ring o. The nut h being turned forward, the pin o¹
is taken along by friction on the ring o², until it is stopped by the stop o, when it
will lift the pawl o in the dotted line position (Fig. 2). By turning nuth backward
the pin o¹ is moved back and the pawl o engages the teeth i.
I, RICHARD WOLFF, of Heilbronn on the Neckar, Germany, Mechanical
Engineer, 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:-
-
The present invention has for its object a safety crank for hoisting cranes, which
permits of the load to be lowered in two different ways; firstly by uncoupling the
device by a short jerk on the crank, when the load will sink under a certain
amount of friction, but without any further work on the part of the attendant,
and secondly by following the sinking of the load by turning the crank
backwardly.
In the accompanying drawing, left with the Provisional Specification
Fig. 1 represents the device in longitudinal section and
Fig. 2 shows a side view of same.
of
The socket c, carrying the driving-wheel b, fits loosely over the crank axle a. A
disk d fits loosely over the flange c¹ of the socket c and carries ratchet
teeth on its outer circumference. A second disk k having no teeth is attached
to the projecting portion c¹ of socket c by groove and tongue. The nut h, being
provided on its outer circumference with teeth i, engages the square thread
the crank axle a. Suppose the crank axle a is turned in the direction of the arrow
(Fig. 1), the nut h will then press against the disks k and d, and the latter in its part
against the socket c, which by the resulting friction is rotated in the sense of the
crank axle. The pawls n and o jump the teeth f and i respectively during the
forward motion of the disk d and the nut h. If the crank accidentally or inten-
tionally is let go, these pawls n and o engage the teeth f and i and the load stops.
If it is desired to let the load sink by applying braking down pressure, the crank
is given a short backward jerk, whereby the nut h is loosened somewhat. The
stop 2 prevents a too far backward motion of the nut h. The load now overcomes
part of the still existing friction between h, k, d and c, and sinks. A recoiling of
the crank of course, cannot ensue, as the nut h is securely locked by the pawl o.
In case the load is to be let down by following the sinking of it with the crank,
the pawl o is to be thrown out, the crank is turned backward and the nut h
loosened. The sinking load and with it the driving wheel b and socket c very
soon attain a velocity, which is greater than the crank motion. The nut h con-
sequently is pressed against the disk k again and a further sinking of the load
would thus be prevented, if not, by turning the crank backwards, the load would
get a chance again to sink. Practically these backward motions of the crank and
the sinking of the load follow each other in so quick successions, that they are
felt as one continuous motion. If the crank is let go, the load will stop.
The present invention has the great advantage over all similar arrangements
that the load can be gotten down either by a continuous backward motion of the

page_text: crank, or by giving the crank a sudden backward jerk, when the load can be
let down by braking it down. The device can be worked in conjunction with a
centrifugal brake of any known construction. In order to prevent the
rattling of the pawl o, while skipping the teeth i of the nut h, a pin o¹ is pivotally
secured at on the pawl o, the lower, roughened end of which glides upon the
outer circumference of the ring 02. The nut h being turned forward, the pin o¹
is taken along by friction on the ring o², until it is stopped by the stop o*, when it
will lift the pawl o in the dotted line position (Fig. 2). By turning nut h backwards,
the pin o¹ is moved back and the pawl o engages the teeth i.
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. In a hoisting crane in combination with the threaded crank axle a, the
toothed nut h, engaging the thread of said axle, the loose clutch socket c, carrying
the driving wheel 6, and having the flange c', the loose toothed disk d and the
disk k, the pawl n, engaging the teeth f of disk d and the pawl o engaging the
teeth of the nut h, as and for the purpose specified.
2. In a hoisting crane in combination with the toothed nut h, the pawl o
engaging the teeth i of said nut, the pin of being pivotally fastened on the pawl o,
the stop of and the ring o², as and for the purpose specified.
3. The whole safety crank for hoisting cranes as described and shown by the
drawing.
יד
1
1
1. 1000