Improvements in Brakes for Hoisting or Lifting Apparatus.
Year: 1894

page_text: Date of Application, 30th May, 1894-Accepted, 30th June, 1894
COMPLETE SPECIFICATION.
Improvements in Brakes for Hoisting or Lifting Apparatus.
I, ANTON BOLZANI of 118 Invalidenstrasse, Berlin in the Empire of Germany,
Manufacturer, 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 has for its object an arrangement in hoisting or lifting apparatus
whereby the automatic slipping down of the load which has been raised is prevented
and the load can only descend when the friction of the brake is overcome by means
of the operating mechanism (handwheel, chain wheel, crank wheel). This arrange-
ment is different from all the devices hitherto employed which have a similar
object, as these latter almost exclusively require the brake to be released when the
load is being lowered, and thereby a jerky movement is caused during the descent
of the load.
This improved arrangement is shown in various forms of application of the
accompanying drawings. The main principle consists in a part of the apparatus
(crank, handwheel, chain wheel, gear wheel, chain pulley or chain drum) which is
placed on any one of the axles of the lifting apparatus (gearing axle or load axle)
and which communicates to or receives power from this axle, being arranged by
means of a threaded part on such axle in such a way that, on the axle and this
part of the apparatus being rotated in opposite directions, an axial adjustment to
one another also takes place. If, therefore, the axle be provided with a fixed stop
against which rests a loosely revolving brake disc provided with teeth on its
periphery, and if a second disc, immovably or unadjustably connected with the
axle, be arranged between the first disc and the part of the apparatus which
imparts or receives the power, a compression of the brake disc between the fixed
stop and the adjustable disc will take place when the part which imparts or receives
the power is rotated on the axle in a suitable direction of rotation corresponding
to the direction of the thread. If, further, the brake disc be prevented by means
of a pawl from revolving in the direction of the descending load, and the pressure
on the brake disc correspond to the lifting of the load, the load can only descend
by overcoming the friction which the brake disc experiences on its side surfaces,
that is to say, when the proportions are suitably selected, it may be kept hanging
with safety and the lowering of the load can only take place by overcoming the
friction of the brake by means of the driving mechanism or parts of the lifting
apparatus (such as the crank, hand wheel, chain' wheel or the like).
Figure 1 shows such an arrangement in its simplest form for a crank axle.
Here a is the crank axle: b, the frame: h, the crank which is screwed on the
threaded part a¹ of the axle, and, by its rotation, approaches to or recedes from the
fixed stop o.
The direction of the thread is formed in such a way that the crank
approaches the stop o when the load is wound up. i is the brake disc provided
with ratchet teeth, which disc is stopped by means of a pawl l, so that it can only
revolve when the load is being raised, and is the intermediate disc which is
adjustably arranged between the crank and the brake disc, but which is prevented,
by means of a spring wedge a², from revolving on the axle a so that it must rotate
with the latter. When the load is raised, the disc i is pressed and gripped between
the stop o and the disc f, and consequently the load is prevented from descending
owing to the action of the pawl. In order, however, to cause the load to descend
by means of the action of the crank without the resistance of the brake ceasing, that
is to say, to allow of the crank being revolved in the descending direction without
removing the brake pressure, the disc f is provided with a ring of side teeth, which
latter are so arranged that a catch or bolt m, which is pressed into the teeth by

page_text: means of a spring, only allows the crank to rotate against the disc f in the
direction of the lifting of the load, whilst it prevents the crank being turned
backwards. If, therefore, the crank be turned in the direction of the descent of
the load, the disc f, and (as the latter is immovably fixed on the axle a) the axle
also is revolved, but only by overcoming the frictional resistance of the brake
disc i.
In order to allow of the brake being again released, the catch or bolt is provided
with a knob which allows the brake to be released by hand, so that the crank may
be turned back on its thread. The nut d is intended to prevent the crank from
being screwed off the axle.
The same arrangement is shown in Figure 2 applied to a part of an apparatus,
which part receives power from the axle. In this case, the chain pulley cis
arranged on the axle by means of a thread a', and, owing to the thread, acts on the
brake parts fand i, which bear against the stop o of the axle a in exactly the same way
as the crank in the arrangement hereinbefore described. In this case also the brake
disc i is, by means of a pawl, prevented revolving in the direction of the descending
load, and the lowering can only be effected by revolving the crank h. Any
stopping between c and fis, in this case, not necessary, as the load, even when the
handle is turned backwards, does not allow the weight on the pressure surfaces to
cease; rather on the other hand, on the crank being turned backwards, the chain
pulley of the wheel e will always revolve simultaneously with the action of the
load, so that the pressure between the pulley c and disc f, and therefore also the
pressure under which the brake disc i stands, are never altered.
If it be desired to use the arrangement shown in Figure 2 for lifting or hoisting
apparatus which allows of the load being raised in both directions of rotation, in
other words, which has either load hooks at each end of the chain, or has two
load chains, one of which is wound up and the other unwound, the arrangement
shown in Figure 3 must be employed. Here, the chain pulley c is arranged on the
crank-axle a in such a way, by means of a thread a', that, in each direction of
rotation of the crank-axle, in which a resistance owing to the load takes place, it
bears against the brake parts i, f, o, or i¹, f', o', which are symmetrically arranged
on both sides of the axle, and therefore one of the two brake discs i or i¹ always
stands under pressure.
Of course, the ratchet teeth of these brake discs must be
opposed to one another, and so arranged that the brake disc which is under the
braking pressure cannot be turned in the direction of the descending load. The
load may thus always be raised without friction whether it bears on the parts of
the lifting apparatus which turn to the right or left, and the load can only descend
by overcoming the resistance of one of the two brakes.
Figures 4 and 5 show the employment of the brake device, not on the gear
axle of the lifting or hoisting apparatus, but on the load axle on which the chain-
pulley or the chain or belt drum is placed. The arrangement is, in this case,
applied to a hoisting block with chain-pulley having a load chain with hooks at
both ends. The chain-pulley c² is arranged on the load axle a by means of a
thread a', and, under the action of the raised load, bears against one of the discs f
or, which thereby causes the brake discs i or to be pressed against one of the
fixed stops o or o' and retain, by means of the pawls, the raised load.
In the arrangements shown in Figures 2 to 5 in which the part which receives
power from the axle and not the one which communicates power to the axle, is
utilised for producing the axial pressure, it is not absolutely necessary that
intermediate discs ff be inserted, as the part of the apparatus which receives the
power may also act by means of a suitable surface directly agains the brake discs i
and . The same action is thus produced.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a braking device for hoisting or lifting apparatus, the combination of a

page_text: brake disc mounted on one of the axles of the apparatus and having ratchet teeth
and a pawl which prevent it rotating except in the direction of the rising load, a
fixed stop on said axle, a disc connected with this axle so that it must revolve
therewith but having an axial adjustment and a screw thread on the end of said
axle on which is screwed the part of the apparatus which receives from or imparts
to the axle the operating power, whereby the action of the load when being raised
produces, by means of the screw thread, an axial pressure which causes a gripping
or compressing of the brake disc between the fixed stop and the axially adjustable
disc, and the raised load is only allowed to descend when the friction of the brake
has been overcome.
2. In a braking device such as described, a bolt or catch on the part of the
lifting apparatus which receives from or imparts to the axle the operating power,
in combination with a disc on said axle, which disc is adjustable axially and is
provided with ratchet teeth on its side into which engages the said catch or bolt
whereby the said part of the lifting apparatus may only be turned relatively to the
adjustable disc in a direction which corresponds to the pressing or gripping of the
brake parts, the said catch or bolt being provided with a knob or the like with
the object of allowing the adjustable disc to be disengaged from the said part.
3. A braking device for hoisting or lifting apparatus such as described in
Claim 1 but having the part of the apparatus which receives the power arranged.
to act directly on the brake disc without the intervention of an intermediate
axially adjustable disc substantially as described and shown.
4. A braking device for hoisting or lifting apparatus such as described in
Claim 1, consisting in the braking taking place by the action of the load, not
merely in one direction of rotation but also in both directions of rotation, by the
part of the apparatus which receives or conveys the power being held on the axle
by means of a screw thread, between two braking devices arranged symmetrically to
it, the brake discs of this brake arrangement being stopped opposite directions,
so that, under the action of the load, one of the two brakes comes into action.
5. A braking device for hoisting or lifting apparatus such as described in
Claim 1, in which a crank is employed as the part for initiating the power.
6. A braking device for hoisting or lifting apparatus such as described in
Claims 1 to 6, in which a gear wheel is employed as the part which receives the
power.
7. A braking device for hoisting or lifting apparatus such as described in
Claims 1 to 6, in which a chain or belt drum or chain pulley is employed as the
part which receives the power.
Dated this 29th day of May 1894
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.